Friday, July 11, 2014


Dr Kiran welcomes all the readers to the blog of Pediatric cardiology department, Narayana Hrudayalaya Hospital, Bangalore.

Recently I met my primary school-mate. Discarded as “mediocre” by my teachers then, he is a successful entrepreneur today! He runs a software firm with 80 people working under him! His company develops custom-made computer softwares and high-end smartphone apps for medium to large scale companies.

“Managing 80 employees must be quite difficult. How do you deal with problem of recruitment and attrition?” I asked him.

His answer was eye-opener. He has simple logic. “I believe in them!” he said. “I select my employees through known circles, mostly through the existing ones. That leads to better accountability and indirect control. But, I assign job responsibilities for everyone as per my assessment. I don’t care about their legacy, the institute they have graduated from or certificates of credentials they carry. CVs are the easiest to fake nowadays and getting references cross-checked is cumbersome. I just want to make sure that they understand what they are doing and how good they are at that work. We pay one of the best packages in this sector. So, I am all about what I want from them.”
“Not that alone”, he continued. “I don’t allow back-biting or speaking negative of anyone. We address workplace problems through a confidential information system where the identity of whistle-blower is completely safe. We have works meant for individuals and groups. If a person does not qualify for either, I fire him! I hate parasites who do not know the work and who live only on the ability of others. To sustain that status, such people usually cause rift between one-another. Their entire existence is dependent on such ill-wills. When one of their hosts realize this, such parasites simply shift their host! Such people are blemish to civilized world. We don’t lose anything by getting rid of them! In fact, on a long run, their absence caters growth of the company.”

“Even better would be sending them to your rivals!” I said jokingly and we laughed.

I was smitten by his insight. He is of my age and how much of worldly sense he has gained by self-industrious path! I was wondering how big time corporates can make use of this principle. After all, ergonomics is the key for eventual profit.

I came across an article in the June 2014 issue of “Journal of Cardiothoracic and Vascular Anesthesia” titled “Extubation in the Operating Room After Cardiac Surgery in Children: A Prospective  Observational Study With Multidisciplinary Coordinated Approach.” Matter of pride is, it is from Narayana Hrudayalaya! Our senior pediatric cardiac anesthesiologists, Dr Rajneesh Garg and Dr Keshava Murthy have authored this.

This was a prospective observational study with controls taken from past, on historic basis. They have studied 1000 patients in the “study group” (age: 1 day to 18 years) with another 1000 historic controls, comprising “before study group”. The study group had undergone cardiac surgery with combination of general anesthesia and neuraxial analgesia with a mixture of caudal morphine and dexmedetomidine. These patients were planned for extubation in the operating room after completion of the surgical procedure. They were compared with historic controls for impact of extubation in operating room on ICU stay and resource utilization.

The authors have been successful in extubating 87.1% of study group patients, including 40% neonates. Of these, 45 required reintubation within 24 hours. The authors observe that overall ICU stay was reduced by 50% in the study group as compared to control group with positive impact on resource utilization.

The authors give a detailed yet lucid account of the patient groups and sub-groups undergoing surgery. They have also documented the factors that lead to deferring extubation in OR. High risk category demanding reintubation has been discussed. They have done detailed statistical analyses of their observations and findings.

The main limitation of this study is utilization of historic controls. This point is acknowledged by the authors. Also, such studies need to be properly blinded to enhance their value and neutralize the bias. The authors have also observed this limitation. But when the number is so large, the chances of bias are not very high, especially when standard protocols are applied as a rule. The cost-benefit analysis is an extrapolated conclusion in this study, with no actual measurements. The authors have acknowledged this fact.

Can this be followed in other centres with lesser numbers and lesser resources? The authors recommend that if early extubation within 2 to 4 hours in the ICU can be practiced, then the re-intubations for re-exploration for surgical bleeding and diaphragmatic palsy can be avoided. They also recommend that perioperative course can be planned in such a way that many patients can be extubated safely at the completion of the surgery either in the OR or early in the ICU, depending on the applicability in that particular center, instead of planning elective ventilation. This helps in keeping a custom-made approach than a blanket version.

The study does not inform the age and weight related mortality in the study group. Weight or Body Surface Area, being an important factor in pediatric ages, could have found a place in their otherwise detailed analysis. Extubation failures related to age and weight/BSA can carry more practical message. Also, if the authors had risk-stratified the patients based on diagnosis and pre-operative conditions, it would have has better impact for those who would like to emulate. Such large numbers are not easy to study. The authors should be applauded for their commendable work. Equal credit should go to the intensive care team for managing the aftermath!

With that, let us get back to few learning scenarios:

306.    CUTTING OFF THE HIGH-WAY

In children with single ventricle physiology with pulmonary atresia, PDA forms the highway for pulmonary circulation along with some collaterals. In cath study, entering PA through PDA is risky. We take reverse pulmonary venous wedge pressures as correlates of mean PA pressure. How much reliability can be attributed to this correlation? We at NH had done a small observational study a couple of years back and found a difference of 2 to 3 mmHg between the two. The question remains, is the cath study required for pre-surgical hemodynamic data in such cases? Wouldn’t interrupting PDA enough to bring down PA pressures to normal? How many centres still follow doing cath studies in such children before single ventricle palliation? Does any centre “not practice” cath study in such scenarios? What is their experience? Please let us know your learnings on this.

307. PROXIMAL COMPLIANCE

We speak of compliance of ventricles a lot. But, we largely take the compliance of atrial cavities for granted. Can there be issues in this regard? Let us take Mitral stenosis or Mitral regurgitation as example. The progress of high PA pressures and RV dysfunction varies in different patients. Can LA compliance be used to explain this variation? Logically, if LA compliance is good, the progress of PAH should be slow. On the other hand, the progress would be faster if LA compliance is poor. Is there any study looking at this issue? What is the personal experience in other centres? Please share.

308. TO CROSS OR NOT TO CROSS

One of the feeders for perpetual tussle between pediatric cardiologist and surgeon is on the coronary crossing RVOT in children with Tetralogy of Fallot. Acts of both commission and omission are held accountable here. Even after advent of CT, this tussle hasn’t doused off. Despite all this, is there any systematic study on the actual disparity between the data on echo report and on-table occurrence? It would be interesting to know this data in high volume centres. Has any centre studied this? It would be interesting to know.

309.ANYTHING LEFT OTHER THAN LEFT?

We have earlier discussed various possibilities of great artery relationship in TGA. We have seen d-malposition, L-malposition, antero-posterior or side-by-side in children with TGA. However, in children with congenitally corrected TGA, we hardly see any relationship other than L-malposition. Has anyone come across any other malposition of great arteries in CCTGA? What is the explanation for this rule? Please let us know.

310.BREATHLESS AFTER SURGERY

What is the incidence of diaphragm palsy after cardiac surgery, which mandates intervention? Diaphragm palsy offers significant morbidity in the post-op period. It also increases the ICU stay, overall expenditure and cumulative mortality. But the actual incidence reported seems quite different from what is usually seen. Is there any reliable data on this? What is the break-up incidence for different lesions? Is there any correlation with CPB time? What is the usual outcome? How many such incidents require placation or other interventions? Please let us know your observations.

That brings us to the end of this post. Please pen in your comments in the comments section. If you find any problem in posting comments, please mail it to my email id kiran.vs.dr@nhhospitals.org I shall post them on your behalf.

Regards

Kiran

Thursday, May 22, 2014

Dr Ravi Ramamurthy has done it again!

This time, he is talking about the statistics part of the erstwhile article we discussed in the previous post: "Risk stratification at diagnosis for children with hypertrophic cardiomyopathy: an analysis of data from the Pediatric Cardiomyopathy Registry". He explains some of the jargon related to medical statistics for the understanding of those who can just spell the word!

Here we go: 
“There are lies, damned lies and statistics” …..

Mark Twain certainly did not have medical biostatistics when he popularized this phrase.
The contribution of statistics to medical science cannot be said in the same light. The weight of a study is determined by its statistics. So let us just take a breather from just satisfying our intellectual taste buds by tasting only the abstract of an article and proceed to actually looking at the entire cooking process.
I was exposed to statistics when I accompanied my mother to the vegetable market.  The potatoes were “sampled”; by size, freshness, color etc. Then they were screened for “predictive markers” indicating their likely shelf life before they reach their “end point” either cooked or rot. And the inevitable remark that out of the last purchase, what percent of the potatoes went bad (“failed to survive”) within a fortnight (“period of observation”). These observations helped us predict and pick the best potatoes.
 In the article under discussion, “Risk stratification at diagnosis for children with hypertrophic cardiomyopathy: an analysis of data from the Pediatric Cardiomyopathy Registry” the clinical implications and its applicability is quite obvious. So the million dollar question would be “Why do we need statistics to prove it?” The answer is simple. Any data needs to be authenticated before it can be applied in practice or replicated. This authentication process is done by statistics.
In this study, two important statistical analytical methods were employed. Let’s discuss them in brief.

Cox proportional-hazards regression:
How important is it?
 It appears in one in ten papers.
How easy is it to understand?
Aim to understand the end result – the “hazard ratio” (HR).
When is it used?
The Cox regression model is used to investigate the relationship between an event (usually death) and possible explanatory variables, for instance observe table 3 & 4 in the article in detail: “Idiopathic, diagnosed at age less than 1 year; Idiopathic, diagnosed at age more than or equal to 1 year; Malformation syndromes; Inborn errors of metabolism; With restrictive cardiomyopathy; With dilated cardiomyopathy.”
What does it mean?
The Cox regression model provides us with estimates of the effect that different factors have on the time until the end event. As well as considering the significance of the effect of different factors the model can give us an estimate of life expectancy for an individual.
Regression and correlation are easily confused.Correlation measures the strength of the association between variables.Regression quantifies the association. It should only be used if one of the variables is thought to precede or cause the other. Interpreting the Cox model involves examining the coefficients for each explanatory variable. A positive regression coefficient for an explanatory variable means that the hazard is higher and thus the prognosis is worse. Conversely, a negative regression coefficient implies a better prognosis for patients with higher values of that variable
The “HR” is the ratio of the hazard (chance of something harmful happening) of an event in one group of observations divided by the hazard of an event in another group. A HR of 1 means the risk is1 × that of the second group, i.e. the same. A HR of2 implies twice the risk.
Kaplan–Meier estimate of the survivor function
To determine the Kaplan–Meier estimate of the survivor function for the above example, a series of time intervals is formed. Each of these intervals is constructed to be such that one observed death is contained in the interval, and the time of this death is taken to occur at the start of the interval. A plot of the Kaplan–Meier estimate of the survivor function (Figure 1) is a step function, in which the estimated survival probabilities are constant between adjacent death times and only decrease at each death. Figure 1 of the said article depicts a step wise graph of the surviving subjects in the study upto five years where the number of surviving subjects can be seen on the Y axis of the graph.

I have tried to simplify these statistical tests, probably a bit too simplified. The intricacies regarding a test lie in deciding where and when to use a certain test. This narration cannot dwell in these details. Secondly the calculations are quite enormous and confusing. But thankfully suitable software are available to carry out these tests. It is imperative for a researcher to be conversant with the various statistical software packages available before embarking on a study. A few examples are Epi 6, SSPS, SAS etc. A researcher should have his statistical test decided before embarking on a study, therefore it is prudent to discuss with a biostatistician beforehand.

So much for now. 

That is Dr Ravi Ramamurthy for you! If you have any doubts or applause, please email  them to kiran.vs.dr@nhhospitals.com or write a comment in the comments box below. It will be honored!                                               

Sunday, May 4, 2014

Hello to the readers!



Our new fellowship student Lt Col Dr Ravi Ramamurthy has agreed to contribute his video presentation on “Natural history of ASD, VSD and PDA” for the readers of blog. Please find the same attached. It can be downloaded from here, but any use of material in the video should be with consent of author. You can write to my email (kiran.vs.dr@nhhospitals.org) for the same.


Please comment on the contents of this video.

Regards

Kiran

Saturday, May 3, 2014

Dr Kiran welcomes the readers to the blog of Pediatric cardiology department, Narayana Hrudayalaya Hospital, Bangalore.

“Working as a team is like work of sled dogs; all the dogs have to put in their best to achieve the maximum result. However, only the lead dog can enjoy the scenic beauty of the journey. If you are not the lead dog, the scenery never changes!” is one of the most satirical quotes on team work by Lewis Grizzard. If one can imagine the picture of dog-sled team, the plight of dogs behind the lead-dog can be easily appreciated.

Every place wherein teamwork is involved would be infested with above situation. I have realized that the most important component of a team is its LEADER. A good and efficient leader (both are mandatory!) can get the best out of even a mediocre team. However, a bad and inefficient leader (either of one!) can break even the best team to tatters. Just imagine a set of brightest minds being led by an unentreprising, negative-toned, escapist, selfish, time-lacking, nepotistic person with sole objective of his own good! Unfortunately, most of the teams in sub-continent face this problem.

A learned friend of mine always laments the lack of leadership in India in general. He attributes it to the prolonged slavery of our masses for centuries. He claims that we are good in taking orders and executing it, but very bad in giving orders and monitoring them. He adds that the cause of moral chaos in most working places of the country is lack of leadership. I have not found a counterargument till now! Leadership, however, has never found any priority in our country. Most of the people were accidental leaders with variable success. May be, we will have a generation in future who understands the need for leadership and would provide the right impetus.

This post, I wish to discuss another interesting article. It is titled “Risk stratifi cation at diagnosis for children with hypertrophic cardiomyopathy: an analysis of data from the Pediatric Cardiomyopathy Registry” by Prof Steven Lipshultz and colleagues for the Pediatric Cardiomyopathy Registry Study Group. The article was published in Lancet in 2013 – pages 1889 -1897. Prof Lipshultz was very kind in permitting me to use his article for discussion in the blog.

The authors start with a premise that treatment of children with hypertrophic cardiomyopathy might be improved if the risk of death or heart transplantation could be predicted by risk factors present at the time of diagnosis. They have statistically analysed data of 1085 children with hypertrophic cardiomyopathy from 1990 to 2009 collected from the Pediatric Cardiomyopathy Registry. Their objective was to understand how patient factors measured at diagnosis predicted the subsequent risk of the primary outcome of death or heart transplantation.

Their analyses revealed that poorest outcomes were recorded for the 69 children with pure hypertrophic cardiomyopathy with inborn errors of metabolism (death or heart transplantation: 57% at 2 years). For children with mixed functional phenotypes, it was lesser. (mixed hypertrophic and dilated cardiomyopathy: 45%, mixed hypertrophic and restrictive cardiomyopathy: 38%). When the child was diagnosed with hypertrophic cardiomyopathy at younger than 1 year, it was 21%. When there was an associated malformation syndrome with hypertrophy cardiomyopathy, it was 23%. The best outcome was for those children with idiopathic hypertrophic cardiomyopathy diagnosed at or after age of 1 year. This group had rate of death or heart transplantation of 3% at 2 years.

The authors have opined that the risk factor for poor outcome included
• Young age
• Low weight or body mass index Z-score
• Presence of congestive heart failure
• Lower left ventricular fractional shortening, or higher left ventricular end-diastolic posterior wall thickness or end-diastolic ventricular septal thickness at the time of diagnosing cardiomyopathy.
For all hypertrophic cardiomyopathy subgroups, the risk of death or heart transplantation was significantly increased when two or more risk factors were present and also as the number of risk factors increased. The authors emphasize the importance of detailed clinical analyses and counseling with improved risk stratification using the data to improve patient outcomes.

The article (Lancet 2013; 382: 1889–97) is important for many reasons. First: the design and analyses of data. Second: clear demonstration of the predictive value of multiple risk factors. Third: benefit to the selected patient groups for early listing for heart transplantation. Fourth: practical utility of the same criteria on global basis. The last one was the basis for my discussion the article here. Reading the entire article is worth the time one invests in it. It would be useful to pediatric cardiologists, genetists, pediatricians, critical care physicians and transplant policy makers of respective countries.

With that let us dwell into the interesting learning scenarios. Just out of interest, I counted the number of such scenarios I have discussed in the past. I have done 93 without using any caption and 210 using captions so far! Did not believe we had so many learnings!! From now on, I would be numbering them accordingly, for the ease of future reference. I will start with no 301 from this post onwards. Whenever we discuss a scenario in future, we shall quote the number.

301. SURGEON’S ROOM!

RV infundibulum is a curious place. Obstruction in this place needs tack and precision to tackle. Anything more would cause undue dilatation and any less would leave residual obstruction which may proceed further with time. We do come across roomy RVOTs after surgical corrections. How many of them would proceed further to formation of aneurysms and diverticulums? Despite doing huge number of congenital heart surgeries, we have seldom come across such instances. Is the better learning curve of surgeons makes any difference? What is the overall incidence of such happenings? Is there a definition or consensus to categorize these lesions? Please let us know your takes on this.

302. CHAMBER OF FUTURE

Formation of RVOT muscle bundle with VSD is a known phenomenon. We owe our knowledge on this to the phenomenal work by Benjamin Gasul and colleagues. I have seen many pediatric cardiologists calling this “Gasulization”! The understanding for the formation of these muscle bundles is the impetus provided by high blood flow across RVOT provided by VSD. By corollary, once the VSD is closed, the growth of these muscles should stop. However, in rare instances, we do come across development of muscle bundles in RVOT even after VSD is closed. The progress is also well documented, with increasing gradients. The obstruction is not an entirely dynamic phenomenon either. Is there any other impetus for development of DCRV other than VSD? How far are these similar to isolated DCRV (without VSD)? What is the natural history of isolated DCRV, which is by and large seen in adults? Please let us know your experience.

303. MAGNETISING THE NEEDS

Problem with newer modalities of investigations is its perceptive utility; it is either over-used or under-used. In a developing country like ours, Cardiac MRI is a premium. Those who can accurately interpret it are even more premium! Owing to the problem, such investigations take huge time to get their utility established. It may the responsibility of professional bodies like PCSI to give a comprehensive set of indications for the utility of using newer modalities like MRI that are appropriate for our country. This will not only improve the utility, it will also avoid the overuse for wrong indications. It is time to custom-make our needs than extrapolating the data from a developed nation blindly. I would love to hear the opinion of readers on this.

304. WHAT’S IN A NAME!

We had a small tussle on nomenclature of coronary artery fistulae recently. One of our senior surgeons suggested that the Coronary artery fistulae terminating in left sided chambers are called Coronary-Cameral and those terminating on right heart chambers are called Coronary Arteriovenous fistula. His argument was so emphatic that many agreed with him. It is true that the Coronary artery fistulae are anomalies of termination, but my understanding of nomenclature was different. Also, it is very difficult to argue with senior surgeons even if you have adequate proof! Anyway, this gave an opportunity to revise the nomenclature. Tiryakioglu and colleagues have defined both these terminologies in their article in Texas heart journal in 2010. As per their definition, Fistulae that arise from a coronary artery and then terminate into a chamber of the heart are known as coronary-cameral, while those terminating into a vein are coronary arteriovenous fistulae. Another very impressive article on this I found was Kim et al titled “Coronary artery anomalies: Classification and ECG-gated multi-detector row CT findings with angiographic correlation in Radiographics in 2006. Worth revising!

305. JUXTAPOSING THE SURGERY

How important is it to diagnose juxtaposition of atrial appendages correctly in the pre-operative period? Not many would know how to diagnose this entity on echocardiography correctly. Most often, such omissions are harmless. However, in certain diagnoses, this entity becomes important. In cases of TGA with juxtaposition, balloon atrial septostomy is a difficult job due to orientation of interatrial septum. Problems associated with Senning and Mustard procedures are well known in Juxtapositions. We have also seen tricuspid valve anomalies associated with these conditions. Our surgeons could recall utility of juxtapositions in Fontan completion. Is there anything other than these? Please enumerate your experiences.


That brings us to the conclusion of this post. Please write your comments in the comments section. If you find any problem in posting comments, please feel free to mail it to my email id kiran.vs.dr@nhhospitals.org I shall post them on your behalf.

Regards

Kiran

Wednesday, April 2, 2014

Dr Kiran welcomes everyone again to the blog of Pediatric cardiology department, Narayana Hrudayalaya Hospital, Bangalore.

I read a short-story published about 3 decades back in one of the Indian magazines. I found it worth sharing: There was an honest man in an office. He meant his work, did it with full sincerity, never gave a chance for anyone to complain. In a chance of event, the management brought in a person with lesser skills, lesser knowledge and higher ego above this honest man. This new person, who was not even one tenth capable, was drawing double the salary of the honest man. Although nothing else changed, the new entry broke the honest man from inside. He started comparing his skills with the new person. He started counting all the contributions he had made to the office over years. He started comparing the strengths and weakness of both and started calculating how much more salary he should command. The sole objective of him coming to the office became discussing this with every single employee of the office including the watchman, lift-man, tea-supplying boy, office-peon and so on. The management was so deft that everytime he logically tried to explain his point, they got their ego hurt and made extremely frivolous remarks on this honest man! He lost peace of mind and thereby the zeal for work. He just became another useless person in the system, gossiping about the impotency of management in rewarding the skills and capability. He was no more what he was so far. This “Avada Kedavra” effect is aptly titled “Murder of righteous”

Such systematic murders are very rampant. Nepotism, caste, influence, glamour and everything other than honesty and principles seem to work! It may be impossible to retain a sane frame of mind to most. To add on, there are people in the system, whose sole objective is to unearth such issues and kill the peace of mind of others! Individual integrity and high degree of self motivation is not easy to achieve. One needs to face the mirror and keep telling oneself about the perpetual need for retaining their honesty and integrity. These testing times have become the rule in today’s corporates. Almost everyone goes through this experience. What is the opinion of readers? How do you retain the sanity in the light of these adverse realities?

I came across an interesting article in online issue of JTCS. This was an accepted manuscript I found online in the first week of March 2014. It is titled “A simple surgical technique for closure of apical muscular VSD” and authored by Dr Amit Mishra et al from U. N. Mehta Institute of Cardiology and Research Center, Ahmedabad, India. Dr Mishra was very kind in allowing the review of this article for our blog.

The authors have presented their innovative and simple surgical technique using custom made low profile polytetrafluoroethylene (PTFE) single disc device for closing multiple apical muscular and isolated apical muscular ventricular septal defects in 17 children. Two children with significant co-morbidities could not be saved out of the cohort of these17 children. The authors have detailed the steps for the preparation of these custom-made devices in their centre.

After echo guided sizing and location of VSDs, the authors have used right atriotomy, opening of IAS, approaching the LV side of VSDs via mitral valve. They have placed the device across the IVS and have sutured it to the septal muscles adjacent to the device. This, they have reported, takes about 15-20 minutes time.

This appears commendable. For, apical VSDs are always delicate issues! Heavy trabeculations on the RV side limits the visibility. Lack of space to work with in the cardiac apex is another limiting factor. Despite early success of left ventriculotomy for dealing with apical VSDs, the risk of aneurysm formation looms large on long-term follow up. The sandwich technique has the risk of residual VSDs.

The authors claim that their technique has the advantage over hybrid techniques in overcoming the limitations and complications of the latter. They also claim that the low profile and plasticity of their custom made device blends well with ventricular geometry in contrast to the commercial devices. Above all, the cost of this custom-made device is estimated by the authors to be about INR 6000 to 7000/- per piece, which is less than one tenth of the commercially available devices!

Any resource-limited country needs innovative approaches to cut the cost down without compromising on the safety. Once the scientific principles are solid and established, there should be way for innovation along the same principles. Now that we have walked a long way with the devices, it is time to innovate and cut downs the costs everywhere to enable utilizing resources to larger masses. Despite being limited by numbers, this paper by Indian colleagues appears way ahead and may be path-breaking. Time is the best umpire.

With that, let us get back to the interesting learning scenarios:

PREPARING WITH REGURGITATION

Among the causes of LV preparation in TGA with intact IVS, the roles of LVOT obstruction or aortopulmonary shunts are well known. We had one infant of 6-months old with TGA and intact IVS. This baby had a congenital mitral valve cleft, resulting in significant regurgitation. The LV was adequately prepared! The child had a successful arterial switch with good outcome. This is one of the rare causes of LV preparation. Please share your experiences on similar rare causes of LV preparation in cases of TGA.

HIERARCHY OF PRIOROTIES

Cardiac transplant in third-world countries is yet to find its place. Barring few anecdotal reports and success, it is still exception than rule. Right from legal issues to emotional issues, there are obstacles. Despite the availability of expertise, the raw-material is of premium. As a result, consensus guidelines are not even attempted. In such cases, how feasible is the advice for cardiac transplant in patients with single ventricles? Very frequently, we see patients of end-stage single ventricles referred from peripheral centres with advice for cardiac transplant. Many a times the advice would be so strong that the pateint’s attendants refuse to leave our chambers till they get “Yes”! It is difficult to understand why such options are given at first hand? Hierarchically, this category of patients does not make it to the top of priorities when the numbers of available hearts are very minimal. Is there a plausible way to deal with such issues? Please let us know your experiences on this issue.

TIMING THE EVENTUAL

We often come across children with CCTGA with VSD associated with pulmonary stenosis. However, the overall shunts would be balanced and these children would be maintaining good saturation with reasonable effort tolerance with no great symptoms. They would eventually require Double switch surgery with atrial switch, LV to aorta tunnel with RV to PA homograft repair. Despite being the corrective surgery, it is massive! Chances of re-do are very high. Many surgeons believe in postponing the surgery to as late as possible. Although the scientific guidelines differ, this approach appears to be very practical in third-world where the cost of surgery and re-do is totally on the parents. Also, the risk of re-do and eventual morbidity should also be accounted. What is opinion of readership? How do you tackle this issue? Where else can we follow this approach? Please let us know.

BIAS OF BACKWARD PRESSURE

It is always maintained that the PAH resulting from pulmonary venous hypertension is reversible. That is the main reason why surgeons bravely march when left-heart events are the sole cause of PAH. Barring cases of pulmonary venous anomalies, this analogy is true. Can the same be extrapolated to events with combination of pulmonary venous hypertension with high Qp? I am referring to TAPVC. It is not uncommon to see an adult with TAPVC! Many surgeons maintain that all TAPVC are operable irrespective of age!! In TAPVC, there is excess Qp capable of causing pulmonary vascular obstructive disease along the lines of ASD. At the same time, there is also some element of pulmonary venous hypertension due to back pressure. How to decide operability in such scenarios? As we all clearly know, cath study is useless in such cases. Is there any way of determining the operability when the findings are not straight forward? Would plethoric chest radiograph or good pulmonary venous returns are enough markers? I would invote the opinions of readers on this issue.

TOT-A-TOTE 

Earlier, we had discussed a child with d-TGA with intact IVS with cor-triatriatum leading to preparation of LV even at the age of 8 months. In contrast, we came across 1-month-old child with dTGA, intact IVS with regressed LV due to TAPVC with small ASD! This child had features of low Qp with good systemic saturations! Our surgeons commented that “half the Senning procedure already done”! LV was not exposed to pressure or volume load, causing early regression. Although many maintain that such LV can be trained, the outcome should be guarded. Not many of this combination would have made it to OT table! It would be interesting if the readers share their experiences on this issue.

With that we conclude this post. Please pen your comments in the comments section. If you find any problem in posting comments, please feel free to mail it to my email id kiran.vs.dr@nhhospitals.org I shall post them on your behalf.

Regards

Kiran

Monday, March 17, 2014

Dr Kiran welcomes everyone to the blog of Pediatric cardiology department of Narayana Hrudayalaya.

With more and more doctors coming back to India after working for few years in abroad, the overall scenario has mixed outcomes. With them most bring the value based, objective diagnostic algorithms which are legally more specific. It would be refreshing to do something more meaningful! At the same time, the differences in the health-care dynamics of a developing third-world nation are far different from that of a developed country. Changing the work patterns en-masse without changing the basic framework of healthcare infrastructure would create a massive mismatch. This is very evident in those corporate set-ups which do not shell out any extra money to improve infrastructure to the levels abroad, but forcefully encompass the working protocols followed abroad! Helathcare providers suffer in such a scenario. Neither party would be ready to listen calmly to the other to identify the problem and to find an amicable solution. In this fiasco, few sane voices get unheard. The entire country is going through a tough transition at present. At this point, it is advantage doctors from abroad, both in term of opinions sought and financial. It is not uncommon to find a low quality person reaping huge financial bargain just for this reason. Only time can tell us how this would impact future trends.

The article of interest I want bring about this week is the Editorial Comment in JACC in its February issue this year. It is titled, “Optimal Timing of Arterial Switch in Neonates in TGA – An Elusive Target” by Dr Tara Karamlou from Dept of Pediatric Cardiac Surgery, Seattle Children’s Hospital, Seattle, Washington. Dr Karmalou starts off with the consensus for Norwood stage 1 and its variations in timing. She mentions about the lack of such consensus for TGA surgery. She draws our attention to the article published by Anderson et al in the same issue of journal about single-institution, retrospective review of 140 selected infants more than 36 weeks’ gestation with d-TGA (with or without a ventricular septal defect) undergoing an arterial switch operation from 2003 through 2012. She talks about the authors’ analysis on the influence of age on surgery on morbidity. She lists the major morbidity defined as cardiac arrest, extracorporeal membrane oxygenation, delayed sternal closure, systemic infection, seizure, stroke on magnetic resonance imaging with clinical sequelae, diaphragmatic paralysis/paresis, reoperation before discharge, or readmission at less than 30 days.
When it came to age, there was a decreasing probability of major morbidity between 1 and 3 days and an increasing probability of major morbidity after 3 days. Dr Anderson’s team has inferred that, based on integration of this dual analysis, an arterial switch operation is ideally performed on day of life 3.

Dr Karambolu opines that findings of this study are important and very timely. She also opines that restriction of the population to a relatively homogeneous group is a major strength of this study. However, she feels that the impact of prenatal diagnosis and the implications of transfer from a referring institution are incompletely evaluated, as they could influence risk stratification. She finally recommends that targeted center-specific internal review to precede externally recommended changes in practice whenever possible.

For developing countries, the timing recommended sounds very elusive. Extremely low number of patients would get diagnosed in this period, let alone reaching the hospital. Even then, the cost of surgery finally falls on the family most often. Very few of them can afford it and even fewer can arrange the money within that short frame of time. This is where the last recommendation of Dr Karambolu stands very relevant to systems in our part of world. Seen in the light of what I discussed at the beginning of this blog post, this sounds even more contrasting.

 Let us move on to the interesting learning scenarios of this post:

BAFFLING REGURGITATION
The initial success of Atrial switch (AKA Senning) surgery depends on how well the baffles function. Surgeons are concerned with smooth flow along baffles to optimize energy dynamics. Hence, they avoid sudden angulations and narrow passages to prevent currents. However, if there is AV valve regurgitation, these aspects would inevitably get compromised. The tricuspid valve which is supporting systemic circulation would be of highest chance to encounter this problem over time. However, in the second natural history, this point does not get as much emphasis as arrthymias or baffle obstructions. Any personal experiences or observations noted? Please let us know too.

BALANCE TO EXPLAIN IMBALANCE
When we learn the causes for hypercyanotic spells in Tetralogy physiologies, right from undergraduate teaching, we are listed causes. Very rarely we dwell into the actual dynamics which result in spells. The chief cause is the delicate balance between PVRI and SVRI. The circulation which contributes higher afterload pushes the flow into other, as both ventricles act as a single unit due to large VSD. The body tries hard to keep the SVRI high to offer a survival advantage to pulmonary circulation. This is the principle mechanism to explain the various stages of cyanosis in same anatomy. Any condition which reduces SVRI would push the blood into systemic circulation to tipp off the balance away from pulmonary flow. Similarly, any condition increasing PVRI would result in same effect. Although the afterload phenomenon is learnt well right from times of physiology in medical school, I often wonder why this explanation is never offered in the dynamics of hypercyanotic spell. Any clarification on this? Please pen in your views.

UNMASKING THE VILLAIN
I have put up this query earlier also, but in a different context. “Pulmonary veins are the farthest structures on echo but should be the nearest ones in our mind” is often used quote specifying the importance of analyzing them. But in low Qp situations, the pulmonary veins can hardly be assessed. In all such cases, we presume them to be normal with limited possible visualization. Very rarely, we may seek cardiac CT. What if some serious pulmonary venous issues get unmasked after a complex high-risk surgery? We often face such issues in post-op period and during follow-ups. Few of them are not even surgically resolvable! Is there any method by which this problem be minimized? CT is a solution, but cost-risk-benefit equation does not fall in its favour as universal antidote! Please let us know your ideas or methods that you have found success with.

DYSMORPHIC QUESTION
This issue is often debated but with no consensus. With pleomorphic clinical presentation of Down syndrome, deciding operability should be tailored for individual child than as a rule. Still, few believe in setting a time frame for additional investigations. Is there any statistics based study on this? Is there any outer limit for age beyond which additional investigations are mandatory? Are the Down syndrome children with borderline operability be safely presumed to have post-op course similar to non-Down group? How do other centres tackle this issue? Please let us know.

PROBLEM OF DIVERSITY
If there is one issue that every centre of pediatric cardiology differ, then it is reporting of investigations like echocardiography, cath procedures, CT and MRI. So much so, one can name the centre just by looking at the pattern of reporting! Even after these many years of dwelling into the subject and formation of Society, why is this disparity? Can’t we universalize our reporting styles? Wouldn’t this be better for mutual understanding, meta-analysis of data, giving a solid platform to tackle legalities and for other unforeseen benefits? Should our identity be based on our idiosyncratic reporting styles? Can the PCSI, IAE and other professional bodies come to some consensus on this? This is an issue worth pondering upon. Please do not hesitate to get yourself involved into this brain-storming.

With that we conclude this post. Please write in your comments. If you find any problem in posting comments, please feel free to mail it to my email id kiran.vs.dr@nhhospitals.org I shall post them on your behalf.

Regards

Kiran

Wednesday, January 15, 2014

Dr Kiran welcomes everyone again to the blog of Pediatric cardiology department of Narayana Hrudayalaya.

I am not really sure if I can still use the term Hrudayalaya (meaning, home of heart), as the institute has deserted its use! Our hospital is now named Narayana Institute of Cardiac Sciences. But, I will continue with Hrudayalaya until I get comfortable with the new name! After all, what is there in a name; every hospital by any other name would smell the same! (with due apologies to William Shakespeare)

I came across an article in 2011 issue of Pediatric Cardiology journal on the utility of 3-D MRI in the coronary anatomy assessment for congenital heart diseases by Rajiah et al from Cleveland clinic, USA. The authors have done a commendable job of using whole heart MRI for coronary artery imaging in 112 CHD patients with mean age of 17 years. They have used a navigator-gated, whole-heart, 3D technique of MRI using 1.5 T machine to assess LAD, LCX and RCA. They have found that the coronary artery origins were visible in 99% with 7% of the patients having anomalies which included 35 patients of TOF, 5 of dTGA, 4 of ccTGA, 6 of suspected coronary anomaly and so on. The mean image acquisition time was 9 minutes amounting to 565 heartbeats. The authors claim that the study happens to be the largest and most comprehensive one using MRI to image the proximal coronary arteries in CHD. The learnings from the authors appears to have a significant impact in future of coronary imaging in CHD. This article is worth a read for anyone involved with management of CHD.

That brings us to the interesting leaning scenarios of this post.

DILEMMA OF SINGLE LUNG

Very often we come across children with significant cardiac defects mandating surgical intervention, but with just one functioning lung, be it hypoplasia or damage due to causes such as infection. The ipsilateral pulmonary artery would behave likewise. This non-functional lung not only imparts great stress on the other lung, but it also contributes to high resistance in the pulmonary arterial circuit. This jeopardizes the operability decisions. What is the optimal management in such cases? How to categorically assess the operability? Is surgical removal of non-functional portions of lung carry better outcome and prognosis? Should the cardiac surgical decisions on these patients be very aggressive? Please share your opinions and protocols followed at other centres.

PSEUDOHORSESHOE LUNG AND SCIMITAR SYNDROME

Multiple terminologies are really confusing! Few claim that the Scimitar syndrome is actually called pulmonary venolobar syndrome. And, there are people on the opposite side to claim that both are different. We had an adolescent boy with CT reported as pseudohorseshoe lung! His angiogram showed us that the right lower lobe of the lung was getting its vascular supply through a collateral from abdominal aorta and its venous return going into right atrium. Chest radiogram showed heart displaced to right and lifted well above the right dome of diaphragm. After doing some vigorous literature search, we found the following learnings:
•    Horseshoe lung: congenital pulmonary malformation usually associated with scimitar. There is fusion of both pulmonary lobes from the posterobasal segments. The fusion is in the retrocardiac area, in front of the esophagus and thoracic aorta.
•    Pleural separation of pulmonary lobes distinguishes pseudohorseshoe appearance from a true horseshoe lung.
•    Scimitar syndrome is also known as hypogenetic lung syndrome. It is a part of the congenital pulmonary venolobar syndrome.

Those who seek more information on this can try Konen et al in 2003 issue of RadioGraphics on Congenital Pulmonary Venolobar Syndrome or Tosun et al in 2012 issue of Iranian Journal of Radiology on Congenital Pseudohorseshoe Lung Associated with Scimitar Syndrome.

TO TIME A TET-CANAL

It is not uncommon to see a child with Complete AV Canal defect with severe RVOT obstruction, resembling a tetralogy situation. This unique combination is often called Tet-Canal or Canal-Tet. Not only surgeon faces a greater challenge in this combination, there is also the question of the right timing. One school firmly believes in postponing the surgery to as later a date as possible, but the other maintains that the Tet-Canal surgery should not be delayed. What do the readers feel? What would be the ideal time to go in for definitive surgery in this subset of children, when the anatomical findings are in favour of complete correction? Please share your views.

EBSTEINS IN ccTGA

One of the most difficult decisions for a surgeon is absence of plan B! Taking Ebsteins anomaly in a child with ccTGA, the surgeon often find himself in the cross-roads! The success of ccTGA repair would depend upon how successfully the Ebsteins anomaly is fixed and how much RV size is re-created. Since the latter is highly variable and the success cannot be instantaneously measured on the table, the decision to go ahead with anatomical correction of ccTGA would be practically risky, more so when the RV size is reasonably compromised. Adding to the woes is the lack of good plan B. What if the Ebsteins correction is suboptimal? This has always been intriguing to us. Please share your opinions and experiences.

PPI TIMING IN POST-OP PERIOD

Use of permanent pacemaker in the post-operative heart block is well established. However, it is the timing which has conflicting opinions. Few wait for 2 weeks, few for 10 days and so on. What is the ideal time? How long would be comfortable if the patient is hemodynamically stable? Please let us know your views.

That brings us to the end of this post. Please write in your comments. If you find any problem in posting comments, please feel free to mail it to my email id kiran.vs.dr@nhhospitals.org I shall post them on your behalf.

Regards

Kiran

Wednesday, January 1, 2014

Dr Kiran welcomes everyone again to the blog of Pediatric cardiology department of Narayana Hrudayalaya.

I have always been partial towards history! When I wrote history of pediatric cardiology in the earlier posts of this blog, a sense of fulfillment was experienced. After all, we are seeing better horizons of science standing on the shoulders of few giants. We should at least know the owners of those shoulders!

I am thinking of introducing those seminal articles and studies which have laid the foundation of pediatric cardiology. Many of them are more than 50 years old! When we talk of some classification or algorithm, we actually do not know the reference. Few learnings just pass on from one generation of students to the next, without even bothering to know who was the original thinker! My idea is to introduce one such article per post. It will not be an exhaustive review, but a brief introduction to ignite!

In this post, I will make a beginning with a fine article, which has stood the test of time for its accuracy.

Questions on the natural history of Patent Arterial Duct (PDA) are very commonly asked in rounds, bedside clinics and examinations. But, how many of us can actually quote the reference? I am referring to “Natural History of persistent ductus arteriosus” by Dr Maurice Campbell, published in British Heart Journal in 1968. Dr Campbell was the first editor of British Heart Journal.

The article starts off with practical difficulties in assessing the natural history of congenital heart diseases in contrast to that of an infection or infarction. Then, it briefs the readers short historical aspects and fast changing trends in the management of PDA.

Spontaneous closure of PDA beyond infancy is discussed with inputs from personal experiences, followed by mortality rates in PDA from time to time. Since many patients of PDA had already reached the age of 20 years or more, the article discusses the effect of operations in such patients.

An interesting aspect of the article is the discussion on the expectations of life for those with PDA. The author has then collected data on necropsies done for PDA patients and has compared the mortalities. Ages of living patients on the data from clinics of three physicians is also given.

The author has taken care to draw his own logical inputs in calculating the incidence of bacterial endocarditis in the PDA cohort and puts it at less than 1% per annum. A passing reference is made to the gender incidence of PDA, but no discussion on why it is universally high in girls.

The article ends with a lucid summary and author drawn conclusions. Few of them are as follows:
• As the years pass, more physicians will be advising operation for a persistent ductus arteriosus with no personal experience of its natural course without operation. It seems important that someone who has seen this period of change should record as much as possible before it is too late. The rate of mortality and the likelihood of other changes in persistent ductus arteriosus can be expressed correctly only when the numbers at risk and the years for which they were under observation are both known.
• We have calculated that the ductus closes spontaneously in 0-6 per cent per annum. Probably the rate is fairly constant, at least for the first four decades. This does not sound very much, but means that 20 ± 3 per cent will have closed by the age of 60. This is our most important conclusion, but it does not mean that an operation which gives a normal expectation of life should be deferred, unless there is already evidence that the duct is closing.
• About the time the first decade changes to the second, the risk of bacterial endocarditis increases to at least 0 45 per cent per annum, and this continues for 40 years or more.
• By the age of 30, our calculations show that about one-fifth of the subjects will have died. From the fourth decade onwards these changes are progressively severe, with a mortality rate rising from 2-5 to 4-0 per cent per annum. By 45, about 42 per cent will have died
• By 60, over 60±10 per cent will have died and the duct will have closed in 20 ± 3 per cent. The article is reminiscent of the commitment of the previous generation to science and future academicians. Reading the entire article is strongly recommended.

One can find the full article free in the following link. 
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC459200/

That brings us to the interesting leaning scenarios of this post. 

LEFT AND RIGHT 

One interesting observation we have made is the early onset of PAH in children with ASD with bilateral SVC. I have written about this combination in the past, speculating that the dilated coronary sinus may act as possible obstruction to mitral valve inflow, simulating Lutembacher physiology, causing PAH. The question was, does physiological mitral valve obstruction occur in post-operative scenarios of this variant or in children with isolated persistence of LSVC? We have not come across such scenarios. I would like to know the experiences of readers in this regard. 

TIGHTENING THE FLOW 

In cases of single ventricle palliation, surgeons prefer to do pulmonary artery tightening when the PA pressures are marginally ore than required. Theoretically, this works. However, we have seen that the effect is much superior in younger age group. How to explain this? Does the amount of smooth muscle in the vasculature matter? Is there a role of plasticity here? How consistent are the observations in different age groups? It would be interesting to know the opinions from readers. 

VALVE AGAINST NO VALVE 

Many centers have approached the problem of free PR in transannular patches. Many surgeons have attempted monocusp, bicusp or tricusp valves made of different materials. Although the results in immediate post-operative periods are good, I don’t know if anybody has done a study on long term results. I would like to know the experience of those centres which consistently use such interventions and their long term results. Please share. 

PERIPHERAL PROBLEMS 

How to approach peripheral pulmonary artery stenosis? The problem is consistent with or without shunts, although the outcome is much better in the former group. It is very depressing to see the CT scans reporting multiple constrictions in the entire length of visible pulmonary arteries. What medications are useful? The problem is very common with syndromic associations. Is that a problem in non-syndromics also? Very less data is available because not many of them would see the OT table. Please share your experiences. 

END TO BETA-BLOCKADE 

In children with recovered dilated cardiomyopathies, when to stop beta-blockers? Is resumption of normal EF the end-point? Should we wait for the LV to come back to normal size? Should ACE inhibitors be continued? I have not come across any guidelines on this. Please share your individual opinions and references if any. 
That brings us to the end of this post. Please write in your comments. If you find any problem in posting comments, please feel free to mail it to my emial id kiran.vs.dr@nhhospitals.org I shall post them on your behalf. 

 Regards 

Kiran