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:

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.

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.

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.

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.

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 I shall post them on your behalf.