Friday, June 4, 2010

Welcome to the readership. This is Dr Kiran inviting you to another post of blog. As previous, we shall see few interesting learning scenarios, few pearls of pediatric cardiology. Before that, as we have been doing since past posts, let us see a small anecdote, which may carry a greater meaning than what it superficially denotes. The following story was told by one of the motivational speakers in a seminar. The speaker was author of multiple best-sellers and does motivational courses nowadays. Please go through this interesting anecdote.

A mother came with her adolescent son to a wise man. It was clear that the boy was brought there by emotional force! He looked uninterested.

“Sir”, the mother addressed the wise man. “This is my son. He is very intelligent, but not focused in life. I request you to give some advice to him”.

The wise man smiled at the boy, who frowned impatiently.

The wise man was indeed wise. He was a modern day Guru. He would not preach or advice atonement or punishments. His words were always more practical than many would think.

“Can we talk about something?” the wise man invited the boy into conversation.

The boy thought of leaving. He looked out of the window. A freshly asphalted road was seen. A small ball of tar was lying at a corner.

“Let us talk about that small ball of tar” the boy said, trying to ridicule the wise man.

The wise man did not get offended. “Can you please get that ball of tar?” he asked.

The boy felt happy. He wanted the “wise man” to give back nicely. He fetched the tar ball and gave it.

“How much do you think this tar ball would cost?” the wise man asked the boy.

“Cost? It is useless; worthless” the boy replied.

“These are basic hydrocarbaons, aren’t they? How much do you think its raw material would have costed?” the wise man had a conviction in his words this time.

“Boy, this fellow knows some chemistry too” the boy thought. He wanted to show off now. “May be, about ten bucks” he answered cautiously.

“Hmmm. Let us get few steps back. This is made of the same basic chemicals used to make plastics I believe?”

“Yes”, the boy was enthusiastic this time. “Vinyls and other polymers would have the basic molecular skeleton as this”

“High quality polymers are expensive. Is the same basic chemical composition applied there also?”

“That is correct. The hydrocarbons have same basic chemical structure. They can be sent through different pathways to obtain different substances. But the basic chemical skeleton remains the same”, the boy was feeling proud this time.

“I hear some of the finest and highest quality materials used in rockets and medical instruments can be prepared using the same chemical framework. I was told by a scientist that these substances cost almost Rs 10,000/- per meter” the wise man said with an innocent tone in his voice.

“You have heard him right. These are very high quality substances that need to be segregated at a very early stage of hydrocarbon processing. The channelization actually matters. Of course, high level of discipline and proper instrumentation along with appropriate environmental standards make all the difference”, the boy knew his stuff and was eager to show off.

“I was told mere ten grams of the basic substance can make high quality thread as long as 1,000 meters. Can it?”

“Of course. Such material used in critical processes may cost about Rs 1,000 a meter” the boy said with full vigor in his voice.

“So, you mean to say this useless, worthless ball of tar could have been something worth a million rupees only if were to get channelized at the beginning”, the voice of wise man was impassionate.

Silence. The boy did not say anything.

“Don’t you think the same process gets reflected in life?” the wise man saw into the eyes of the boy.

The boy bent his head. Words were struck in his throat. “Yes” he said slowly.

“Power, knowledge and intelligence may not reach where it deserves unless it gets a sense of direction and channelized into the proper pathway. It is left to you whether you wish to end up Rs1000 a meter or a waste mass of material at a deserted corner of road”, the wise man stopped.

The boy choked. The message was conveyed.

I remember one of my physics lecturers telling the class. “Be a vector. Your energies are nothing without the element of direction.” Not many of us could understand or appreciate what he told at that age. However, the words remained with me. I see a greater meaning now for the same. Every day, the same message gets extrapolated in many fronts. Even when it comes to management of heart problems, we often see how the small steps kept at early phases of disease process end up being great benefits for the child. Similarly, how small mistakes at the inception end up being a disaster for the patient. Appropriate channelization, whether in life or in any trifle looking setting, is indeed a big task. I felt like sharing this anecdote for the final punch it delivers and the resultant impact!

With this, it is time to get back to our regular feature: Interesting case scenarios:

INEVITABLE LAST MINUTE

We had 8-year-old with single ventricle physiology with IVC interruption and pulmonary atresia and intact IAS. How would the cath for single ventricle suitability help? We cannot enter the PA, cannot get the pulmonary venous wedge or have any way of measuring the PA pressures. Since it is a potential Kawashima, unless the data is clear, the decisions are pending. We contemplated this, yet went on with cath. Cath study did not spring any surprises and no clear data could be obtained. It was left to “on the table” decision making. Is there any other way of getting the data from cath? Please let me know your opinions on such scenarios.

POSSIBLY POSSIBLE!!

Is there a possibility of transposition of great arteries with {S,D,S} combination? In other words, can we have normally related great arteries in transposition diagnosis? The words sound paradoxical. However, we came across such a report done from outside. On repeating the echo, we found a DORV, NRGA, VSD, severe PAH. The commitment of PA was unclear and could be routed to RV or LV depending on how the patch is to be directed. When we put up the question on the possibility of outside report, we were surprised to hear that {S,D,S} in TGA is possible and reported. Has anyone come across this combination? If so, please send the details. We shall put it up in the subsequent posts.

CALCIUM DYNAMICS: IS PREDICTION POSSIBLE?

We had one 11-year-old girl, who had undergone RV to PA homograft conduit repair about 11 months back. The girl came back with calcification of homograft with severe obstruction. On the cath study, we found calcification on the VSD patch also! The surprise element was the rapidity with which the calcification had occurred and progressed. The surgical team introspected about the type of valve. They wanted to see the records to find out if it was an antibiotic prepared valve or a cryo preserved valve. Does it actually matter? Is there any way in which we can predict the calcification? Are there any observations regarding these issues? Please let me know your experiences on this.

NUMERICAL DILEMMAS

Sometimes, the initial assessment of a patient with high Qp and sever PAH shows clear operability on clinical assessment and basic investigations. However, the cath data on the same patient may not show the same picture. We had one 8-year-old of CCTGA, VSD with PAH. He was saturating 98%. However, the surgical team sought a cath study to ensure the anatomy. On the cath, the PVRI was 14.8 wood units! The surgery was ruled out due to the numbers. Many of us would have come across such situations. Is there a cut off for ordering additional investigations? If there is a disparity between the numerical values and clinical findings, doesn’t the latter get precedence? How to resolve such issues? If you have found any solution for these scenarios, please let us know.

COLLATERAL DAMAGE

We come across scenarios wherein the patients with single ventricle physiologies saturating well would be put on Glenn shunt for reducing the volume loads. We had a 2-year-old with single pump physiology saturating 92% in room air. He had good aortopulmonary collaterals. How should we go about dealing with these collaterals after the Glenn shunt? Do the saturations come down if we ligate the collaterals? Is a low SO2 after surgery acceptable? If we leave the collaterals, is the risk of overflow and volume load higher? The senior surgeons always maintain that the collaterals are self limiting and if jobless, they would involute by themselves. Is that true? If so, how long do they take? Is accepting low saturations better than risking overflow and volume load? The surgeons were reluctant due to issues related to approach. They suggested that we can coil the collaterals post op. What is more logical? If any other institute has any consensus on this issue, we would be interested to know their logic.

PEDIATRIC CARDIOLOGY PEARLS:

21. Arterial malformations have two vascular patterns: Arterio Venous Malformations (AVM) and Arterio Venous Fistulae (AVF). AVM (microfistulas) are multiple arterial feeders joined via a nidus to draining veins. AVF (macrofistulas) are direct shunts between large arterial and venous channels. (Avery JB, ed. Cardiovascular Pathology in Infants and Children. Philadelphia: WB Saunders, 1984 page277)

22. The relationship between development of aortic arch and migration of neural crest cells into the pharyngeal arches was given for first time in 1991 in avian embryo studies. (Kuratani S, Kirby ML. American Journal of Anatomy 1991 page 215)

23. Normally, there are two right and two left pulmonary veins. The most common variation is the presence of a single pulmonary vein on either the right or left side, with a prevalence of about 24% in anatomic studies. Contrary to the popular belief, the prevalence of a third pulmonary vein on either the right or left side is only 1.6% to 2%. (Healy JE Jr. Journal of Thoracic and Cardiovascular Surgery 1952 page 433)

24. The persistent Left SVC opens into coronary sinus and drains into Right atrium. Hence, the coronary sinus enlarges in presence of left SVC. This interferes with blood flow from the left atrium into the left ventricle. An increase in the magnitude of the left-to-right shunt at the atrial level was found in patients with secundum atrial septal defects (ASDs), persistent LSVC, and dilated coronary sinus. (Byerregaard P, Laursen HB. Acta Paediatrica Scandinevia 1980 page 105)

25. Left axis deviation in ECG is found in moderate VSD. However, large VSDs and equal ventricular pressures demonstrate right ventricular hypertrophy pattern in ECG. (van den Heuvel F, Timmers T, Hess J. British Heart Journal 1995 page 49)

This brings us to the end of one more post. I had sent the emails to all the known followers last time. If anyone is following the blog and has not become a follower for any reason, please send your email id to me on drkiranvs@gmail.com I shall include your mail id in the list to be informed. Also, send your feedbacks by email or via the comments section.

Regards

KIran

2 comments:

  1. Regarding the pulmonary venous anomalies . How often do we actually see a single pulmonary vein on either side in day to day practice ?

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  2. You are right. We do not see many. Or, we do not make effort to see all 4 pulmonary veins in routine echo, unless pulmonary veins are an issue. The study quoted is from 1952 - likely to be autopsy and angio based. Since echocardiography or cardiac CT happens to have replaced both for pulmonary veins, it may be difficult to replicate the numbers. However, makes good material for a study. Why not take up a study on number of pulmonary veins in, say, 500 cases and report. Also, there are cardiac CT for non-CHD cases too. Can we make it a point to study pulmonary veins in them and report a couple of hundred cases? Nice point. Thanks for bringing it up.

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