Letter by ElBardissi Regarding Article, “Outcome of Alcohol Septal Ablation for Obstructive Hypertrophic Cardiomyopathy”
To the Editor:
Sorajja et al1 report the most comprehensive analysis of septal myectomy versus septal artery ablation, continuing to elevate the debate regarding the optimal intervention for patients with severe symptoms due to the obstructive variant of hypertrophic cardiomyopathy. Although there were no significant differences in medium-term survival rates (extended out to a median of 2.2 years), patients who underwent septal artery ablation were more symptomatic at follow-up when compared with an age- and gender-matched cohort who had undergone septal myectomy. Furthermore, a higher rate of postprocedure complications existed in patients who underwent ablation. Although their article provided insight into the natural history of both procedures, a number of questions remain unanswered and would benefit from clarification.
With regard to the survival analysis performed, the authors did not comment on those patients who initially underwent septal artery ablation and subsequently required myectomy. If these patients were included in the latter cohort, the survival analyses may be inappropriately skewed in light of a previous report that found poor survival rates in patients who underwent myectomy after ablation.2 Additionally, it is known that patients requiring myectomy as a consequence of failed ablation (often times multiple failed ablations)2,3 appear to have preprocedure clinical characteristics that may have predicted failure, such as abnormal coronary anatomy not supplying the appropriate portion of the basal septum.2,3 What is not known, however, is the number of patients with seemingly abnormal anatomy that underwent successful ablation without postprocedure complication. These findings would allow for appropriate patient stratification, which should not be taken lightly given the unacceptably high rate of complications and death after myectomy after failed ablation.2,3 Finally, the long-term survival and success rates of ablation should be interpreted with caution. Previous reports have found that many patients will attain an immediate postprocedure gradient consistent with success, which is often times attributed to myocardial stunning that occurs in the context of recent infarction rather than successful ablation.2,4 In fact, for those patients presenting for myectomy after ablation, the median time to representation was approximately 500 days,2,3 suggesting that many experienced an interim period of symptom relief and gradient reduction before presenting for reintervention. The authors1 only report survival rates out to a median of 2 years; consequently, many patients included in their analysis may require reintervention because of persistent obstruction, which is suggested by a high rate of severe symptoms in patients who underwent ablation in comparison with an age- and gender-matched group that underwent myectomy.1
Sorajja P, Valeti U, Nishimura RA, Ommen SR, Rihal CS, Gersh BJ, Hodge DO, Schaff HV, Holmes DR Jr. Outcome of alcohol septal ablation for obstructive hypertrophic cardiomyopathy. Circulation. 2008; 118: 131–139.
Maron BJ, McKenna WJ, Danielson GK, Kappenberger LJ, Kuhn HJ, Seidman CE, Shah PM, Spencer WH 3rd, Spirito P, Ten Cate FJ, Wigle ED. American College of Cardiology/European Society of Cardiology clinical expert consensus document on hypertrophic cardiomyopathy: a report of the American College of Cardiology Foundation Task Force on Clinical Expert Consensus Documents and the European Society of Cardiology Committee for Practice Guidelines. Eur Heart J. 2003; 24: 1965–1991.