Author + information
- Paul F. Kantor, MB.BCh, DCH* ()
- ↵*Hospital for Sick Children, Cardiology, 1725 I, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada
Drs. Singh and Almond engage in some useful conjecture, but their argument is not supported by published data, including our own (1). Much of their argument revolves around the possible interdependence of the choice for angiotensin-converting enzyme inhibitor (ACEI)/beta-blocker therapy and the selection bias for transplantation in “sicker” patients who may have been on these therapies. They speculate that the bias to perform transplantation on sicker patients undergoing treatment with ACEI/beta-blocker therapy artificially and negatively skewed the survival of these patients with the arrival of the transplant era.
However, the introduction of ACEI therapy in our series (1) occurred many years before (1983) the availability of heart transplantation, and in the case of beta-blocker therapy, most patients (1998 to 2004) began to receive this well after transplantation was established. Moreover, we showed that the patients most likely to die or receive a transplant were those who did not receive any oral agents. Regarding the propensity for transplantation, we have acknowledged this limitation, but have also shown that the advent of transplantation did not change the probability of the combined end point (death or transplantation) being reached when the pre-transplantation and current eras were compared. In addition, and contrary to their assertion, we did not show that patients receiving digoxin were more likely to die than to receive a transplant.
Drs. Singh and Almond's concern that transplant availability acts as a bias in treatment strategy is overwrought and also unsupported by any data. Almost every patient in our practice has undergone transplantation from a status of refractory heart failure, thus representing a de facto failure of medical therapy and justifying the concept of a composite end point. This concept is also broadly accepted in the pediatric cardiology literature (2,3).
We agree, however, that there has been a tendency to treat patients with these medications absent a compelling level of evidence, and we believe also that our experience is helpful in demonstrating equipoise regarding their effectiveness in this setting. Our data emphasize the need for adequately powered prospective randomized trials of therapy for children with this group of diseases.
- American College of Cardiology Foundation
- Kantor P.F.,
- Abraham J.R.,
- Dipchand A.I.,
- Benson L.N.,
- Redington A.N.
- Tsirka A.E.,
- Trinkaus K.,
- Chen S.C.,
- et al.