Friday, November 5, 2010

Dr Kiran welcomes all to this new post of pediatric cardiology blog.

I have often thought if I should wind up the blog. It takes lots of time for me to get the things compiled. It takes keen observation and note-making to get the facts correct. It takes good amount of thinking to write in a language different from my mother-tongue. When the blog was started, the name was chosen carefully so that everyone in the department would think it is their own and would contribute. All these expectations went the same way my other expectations go.... right into the drain!

Still, I am continuing it. Since the comments I get are minimum, I don’t even know if anyone is reading the blog at all! So, even if I stop, I don’t think anyone would be affected. “We never knew you existed; anyways – good bye” would probably be the response. When something does not make any difference, why bother?

Despite the apparent pessimism, I shall continue this blog as long as feasible. It gives me an opportunity to be alert, express, think and explore. It has given me new ideas on learning. It has taught me how to work (for blog) without expectation (of comments). The time investment done on this blog is not a waste for me as of now atleast. Of course, bitter pills would not matter if one is sure of the commitment.

Let me congratulate our fellows for their enthusiasm to explore. An idea originated when I was writing for one of the posts for this blog. I proposed debating for the fellows in the department as a part of their academics. I hand-picked about 25 topics and ran through the available literature. I chose those topics which had good number of pros and cons. A list of 5 topics were given to the fellows and they chose one topic for the first-ever debate for Pediatric Cardiology fellows at NH. The topic they chose was “The role of ACE inhibitors in Post-Fontan status”. They debated well with a great deal of zeal and preparation. Congrats to Drs Shweta Nathani, Kavya Mrutyunjaya, Prashanth Patil and Dhanya Warriar – good job; keep it up!

Let me get to our new feature of the blog: The current status of controversies in pediatric cardiology.

This post, I have chosen Eisenmengarization. We shall ask few questions and check the level of evidence for each of them whenever available or get some support from literature.

Q1. The role of long term oxygen therapy:

Oxygen therapy on the first look appears to be an impressive choice. In 1985, Bowyer et al reported the ‘Effect of long term oxygen treatment at home in children with pulmonary vascular disease’ in British Heart Journal. Improved survival has been reported in a small group of children with pulmonary vascular disease receiving long-term oxygen therapy. This study was quoted to advocate the use of routine home oxygen therapy. However, a much larger study by Sandoval et al in 2001 on ‘Nocturnal oxygen therapy in patients with the Eisenmenger syndrome’ got published in the American Journal of Respiratory and Critical Care Medicine. The study showed that nocturnal oxygen therapy did not improve symptoms, exercise capacity, and outcome in adult patients with Eisenmenger syndrome. Hence, home oxygen therapy is a class IIb indication. Routine use of long-term oxygen therapy cannot be recommended. However, selected patients with associated lung pathology may benefit from oxygen inhalation. (level of evidence:B)

Q2. The role of Bosentan:

The BREATHE-5 (Bosentan Randomized Trial of Endothelial Antagonist Therapy) trial by Galie et al published in Circulation in 2006 looked at Bosentan therapy in patients with Eisenmenger syndrome. It was a multicenter, double-blind, randomized, placebo controlled study. Here, bosentan improved exercise endurance at 16 weeks, without any deleterious effects on gas exchange. As the level symptoms in the enrolling subjects increase (class III and IV), the results are likely to be earlier and better. However, in a retrospective study published by Adriaenssens T et al in European Heart Journal in 2006 titled ‘Advanced therapy may delay the need for transplantation in patients with the Eisenmenger syndrome’, no survival advantage could be demonstrated among those who received the newer therapies in comparison with those who remained on standard care. Many of these patients out of a cohort of 43 had class II symptoms. Hence, use of Bosentan is a class I indication. Bosentan may be used in patients with the Eisenmenger syndrome with class III symptoms to improve exercise capacity and hemodynamics. The long-term benefits of any drugs in this syndrome should be evaluated on the basis of long follow-up periods. Results of studies with this design are not available at present. (Level of evidence:B)

Q3: Role of Anticoagulation

Broberg and colleagues have done extensive research on this issue. In one of the articles titled ‘Massive pulmonary artery thrombosis with haemoptysis in adults with Eisenmenger’s syndrome: a clinical dilemma’, published in Heart in the year 2004, they showed the tendencies in such patients for the development of pulmonary arterial thrombosis. This was followed by another study of theirs published in the Journal of American College of Cardiology in the year 2007, titled ‘Pulmonary arterial thrombosis in Eisenmenger syndrome is associated with biventricular dysfunction and decreased pulmonary blood velocity’. These studies pointed at the advantages of routine anticoagulation in this subset of patients. However, the risk of bleeding episodes cannot be negated at the same time. One needs a fine balance between use and monitoring. Since the risk of bleeding exceeds the benefit in the potentially unmonitorable subgroup, the routine use of anticoagulation falls under class IIb indication. The routine anticoagulation is still remains controversial in patients with the Eisenmenger syndrome. Marked blood hyperviscosity, altered chest tomography suggesting pulmonary arterial thrombosis, and chronic atrial flutter or fibrillation are findings that may point toward the need for anticoagulation. However, chronic anticoagulation should be avoided if adequate monitoring is not feasible. (Level of evidence:C)

Q4: Pregnancy and Eisenmengarization

Yentis and colleagues in 1998 did a systematic survey in this regard. Their article titled ‘Eisenmenger’s syndrome in pregnancy: maternal and fetal mortality in the 1990s’, published in British Journal of Obstetrics and Gynaecology showed a substantial risk of mortality to both fetus and the mother. The same opinion was shared by Diller and Gatzoulis in the year 2007. The article titled ‘Pulmonary vascular disease in adults with congenital heart disease’ published in Circulation reiterated the same opinion. The risks of pregnancy should be explained to women with the Eisenmenger syndrome as soon as the diagnosis is confirmed and the options for contraception should be given. Thus, avoidance of pregnancy becomes a class I indication. Early termination of pregnancy is recommended. Careful monitoring and specialized follow-up of inevitable pregnancy in selected cases is advised. (Level of evidence:C)

Q5: Routine phlebotomy

Perloff and colleagues have detailed this issue many times. In an article published in the Annals of Internal Medicine in the year 1988 titled ‘Adults with cyanotic congenital heart disease: hematologic management’, they documented worsening of iron deficiency with phlebotomies. They had an argument that the compensated secondary erythrocytosis is better tolerated and does not mandate routine blood-letting. In another article published in 1993 in Circulation titled ‘Risk of stroke in adults with cyanotic congenital heart disease’, an increased risk of stroke was also documented by them. Broberg and colleagues in 2006 published their data in the JACC titled ‘Blood viscosity and its relationship to iron deficiency, symptoms, and exercise capacity in adults with cyanotic congenital heart disease’, showing a further reduction in exercise tolerance with phlebotomies. Phlebotomies should be indicated strictly to relieve hyperviscosity-related symptoms such as blurry vision, headaches, dizziness, arthralgia and worsening of dyspnea. In all instances, maintaining an iron-replete state is crucial. Avoidance of phlebotomy is a class I indication and the level of evidence is B.

This marks the end of this topic. In future, I intend to take up an issue of importance and address atleast 5 questions with appropriate studies and available evidence. Hopefully, it should be of assistance to anyone interested in these topics. Any further queries can be addressed in the comments box or to drkiranvs@gmail.com I shall try to address those questions on timely basis.

Any suggestions about this new section are welcome.

With this, let us get back to our regular feature: Interesting learning scenarios:

HIGH YET LOW

In cases of transposition of great arteries with small ASD and large VSD, the desaturation is usually disproportionate to the extent of lesion. We had a 2 year old with TGA, large non-routable VSD, small ASD and severe PS with SO2 of 60%. The PA pressure on cath was 15mmHg. The issue was to go for a BD Glenn shunt. On chest radiograph, the Qp was not bad and the echo showed a satisfactory pulmonary venous return. So, it is just not the Qp which is the cause for desaturation here. The more likely culprit might be the inadequate ASD. Despite the presence of a large VSD, it is the interatrial communication that more effective in mixing. Hence, the argument was to add an atrial septectomy to BD Glenn. The problem is, for atrail septectomy, the patient has to go through the bypass pump, whereas BD Glenn is done off-pump. So, one has to be categorical in showing the benefit for subjecting someone to pump. What is your experience in this issue? Please let the others know.

USE AND MISUSE

“Is the diagnositic cath an entity in the current practice of pediatric cardiology?” is a hotly debated subject. The pros and cons are numerous. However, some amount of discretion can definitely be entertained in this regard. The grey zones are in plenty and the decisions may fluctuate with regard to merit of the case. I have discussed a 2-year-old in one of my earlier posts. This kid had a large VSD, a moderate ASD and PAH. In such combination, we would expect RA and RV to get dilated. However, this child had LA and LV dilatation. The TV annulus corresponded to zero Z-score and RV was tripartitie and reaching apex. Since the child saturated 94% on room air, had plethoric lung fields and the shunts were completely left to right, the operability was not doubtful. However, the paradoxical size of RV was worrisome. Cath may give us RV EDP. How useful would this data be? Cath was done, but RV injection was not done due to severe PAH. The final data acquired showed operability. Can such caths be avoided? There was nothing of importance that could not be predicted. Finally, the surgery was the same as pre-cath recommendation. What is the opinion of the readership? How would other institutes handle such issue?

HALF OR ONE-AND-A-HALF?

We had a 4-year-old with a large VSD, smallish TV, smallish RV (not reaching apex) and a moderate sized ASD. The ASD shunted right to left. There was some antegrade flow through the muscle bundles of RVOT. On cath, the PA pressure was 12mmHg. The decision was between an isolated BD Glenn shunt against a one-and-a-half ventricle repair. The latter would definitely be a superior option, but would involve resection of RVOT muscle bundles. The effectiveness of RVOT clearance would determine whether the ASD should be kept open or not. Also, if the pulmonary valve gets inadvertently damaged in the process and starts leaking, the efficacy of Glenn would come down and the smallish RV may not take the additional load of PR. This may again necessitate the ASD to be kept open. The overall picture would indicate a delicate balance. How controlled can such procedures be? Is risking a delicate balance between a fine RVOT with no damage to pulmonary valve a superior option to a non-risky BD Glenn? How would the readership vote? Please let me know. I shall update you on the outcome of this child.

ACQUIRED RESTICTIONS

Can Tricuspid atresia with restrictive ASD live upto 8 years without any intervention? Looks like an unusual association. We did see an eight year old with this picture saturating 74% in room air. The RA pressure was 12mmHg and the LA was at 8mmHg in a tricuspid atresia IIB. The cath data was otherwise OK for single pump repair except for the low McGoon ratio of 1.5. The decision was to go for a BD Glenn shunt. The same question popped up again: Should septectomy be added? One argument was not to trust the numbers of cath data and to go ahead only with off-pump BD Glenn. The other argument was a possibility of an acquired restriction of interatrial communication and thereby giving rise to symptoms as well as the numbers shown in the cath data. Is the acquired restriction of interatrial restriction possible as a part of natural history of tricuspid atresia? Is such a thing reported or seen? Please let me know your experience.

ALL OR SOME OR NONE

It was a conflict of contrasts. We had an 11-year-old saturating 75% in room air but with surprisingly active (NYHA Class 1 symptoms) with balanced AV canal defect, DORV, d-malposed great vessels with supracardiac TAPVC to SVC-RA junction. The conflict in the clinical picture led to the conflicting opinions. The cath data otherwise suited Fontan repair, but the co-existing TAPVC was not in favour. The question was whether a simple BD Glenn be done or not. One argument was that at 11 years of age, isolated BD Glenn would only be adding to surgical risk without much benefit to an already asymptomatic child. The other argument was to do with his SO2. At 75% SO2, even a 25% cardiac output ensured from BD Glenn shunt into the Qp along with some antegrade flow from RVOT would be far superior over a period of time than leaving him alone. So, rerouting the TAPVC to LA and a concomitant BD Glenn was to be considered. Of the three choices (Fontan OR BD Glenn with TAPVC rerouting OR nothing) which would you favour? Do you have any different logic to justify your stand? Please let me know.

PEDIATRIC CARDIOLOGY PEARLS:

96. Systemic arterial desaturation is present to some extent in every patient with tricuspid atresia because of complete admixture of the systemic and pulmonary venous returns. Hypercyanotic spells can occur in patients with tricuspid atresia as a result of either a decrease in the size of the VSD or infundibular narrowing. (Dick M, Fyler DC, Nadas AS. Tricuspid atresia: Clinical course in 101 patients. In American Journal of Cardiology in the year 1975 page 327)

97. Scimitar syndrome is associated with other anomalies, including hypoplasia of the right lung, anomalies of the bronchial system, horseshoe lung, secondary dextrocardia, hypoplasia of the right pulmonary artery, anomalous arterial connection to the right lung from the aorta, and pulmonary sequestration. (Gao Y, Burrows PE, Benson LN, et al. Scimitar syndrome in infancy. In Journal of American College of Cardiology in the year 1993 page 873)

98. In 1942, Streeter proposed classifying human embryos in 25 age groups, or horizons, each representing 2 days of embryonic life. He later omitted the last two stages because he thought that stage XXIII could be considered the last stage of embryonic development. This approach has been generally accepted for determining the age of human embryo. (Streeter GL. Developmental horizons in human embryos: Description of age group XI, 13 to 20 somites, and age group XXII, 21 to 29 somites. In the journal Carnegie Institutes Contributions to Embryology in the year 1942 page 211)

99. During fetal life, the partial pressure of oxygen to which the ductus arteriosus is normally exposed is 18 to 28 mm Hg. An increase in pO2, as occurs with ventilation after birth, constricts the ductus arteriosus in mature fetal animals. (Heymann MA, Rudolph AM. Control of the ductus arteriosus. In the journal Physiology Review in the year 1975 page 62)

100. Two major types of vascular anomalies were defined: Hemangiomas and malformations. Hemangiomas are benign tumors of infancy that demonstrate endothelial cell hyperplasia during the postnatal period (proliferative phase) and that undergo spontaneous regression over a 5- to 8-year period (involutive phase), without metastasis. Vascular malformations result from errors of vascular morphogenesis; they grow commensurately with the child and exhibit a normal rate of endothelial cell turnover. Vascular malformations are subdivided anatomically into groups based on the predominant anomalous vascular tissue: Capillary, lymphatic, venous, arterial, or a combination of vessel types. (Mulliken JB, Glowacki J. Hemangiomas and vascular malformations in infants and children: A classification based on endothelial characteristics. In journal of Plastic and Reconstructive Surgery in the year 1982 page 412)
With this, we wind up this post. I would be interested in your comments on the new section. Please use the comments link. Click on ‘comments’ to open a comments box and post your writing in it. Or you can also use my email id drkiranvs@gmail.com to put up your comments- both careful and caustic are welcome!

Regards

Kiran

6 comments:

  1. THIS BLOG IS SOMETHING THAT THE ENTIRE PEDIATRIC CARDIOLOGY COMMUNITY CAN FOLLOW AND CONTRIBUTE IT IS THE LOSS OF THOSE WHO DON T .THERE IS NO QUESTION OF LETTING ALL THE GOOD EFFORT GO . IT IS A LEARNING EXPERIENCE FOR EVERYBODY .
    I think it is a good idea to add the "current status of controversies " to the blog .
    Regarding the role of Bosentan . Are the studies that have been done include children or do the mostly include adults as I come to understand ?
    And since it is well known fact that ASDs decrease in size over time I guess the same could hold true irrespective of the underlying diagnosis whether it is a Tricuspid Atresia or not.And we definitely need to do an atrial septectomy because the atrial communication can get smaller !

    Dr Prem Alva
    Narayana Hrudayalaya

    ReplyDelete
  2. That was Dr Prem Alva, our new consultant in Pediatric Cardiology, Narayana Hrudayalaya

    Thank you, Dr Prem Alva. That was very encouraging.

    I agree with you on Bosentan. There is minimal data on pediatric population. The data available is largely extrapolated from adult studies. But for the lack of better alternative, we have to accept whatever is available.

    The ASD logic is well structured by you! However, the large ASDs would still remain non-restrictive in most cases, although the size indexed to BSA changes to lower side. This case had the novelty of being a mandatory shunt becoming small, which is seldom seen.

    I would be happier if you can contribute to the content of blog. Good beginning anyway.

    Kiran

    ReplyDelete
  3. Dr Vishal Changela, who trained with us at NH, is now an independent pediatric cardiologist at Ahmedabad. I received this response from him on email: posting it on his behalf-

    1. I think that cath for "RVEDP" was not required. Senior pediatric cardiologist at amrita told me recently that ratio of diagnostic vs theraputic cath is now 20:80 at their centre.

    2. Atrial septectomy is very quick procedure, requires very less bypass time. I spoke to local pediatric cardiac surgeon and he was in favor for atrial septectomy for mentioned scenario. Personally i advocate atrial septectomy.

    Thank you, Dr Vishal. I hope to get some more from you in future.

    Kiran

    ReplyDelete
  4. dear dr kiran
    many are reading this blog although thay may not be contributing to it by writing coz perhaps they are not so got eloquent expressive as u are. not everyone can become a spokesperson.its start only, have patience . why dont u ask dr sunita or dr suresh or other senior faculty members to contribute once in a while.luv anamika

    ReplyDelete
  5. Good blog.
    I am following
    My medical blog is here:
    http://tabibqulob.blogspot.com/

    ReplyDelete
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