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