Ablation may raise risk for later myectomy

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Bias towards surgery?

Surgeons have a bias toward always seeing surgery as the better alternative, and that may explain the conclusion Dr. Eduard Quintana and his colleagues stated in this study – that the accumulating evidence suggests that the myocardial infarction induced during percutaneous alcohol septal ablation may have harmful effects, Dr. Richard Lee said in his commentary. (J. Thorac. Cardiovasc. Surg. 2014 [doi:10.1016/j.jtcvs.2015.05.019]) “I am not sure this is true,” he wrote.

He noted that the authors’ acknowledged limitation that the denominator is not known is a “critical shortcoming.” Dr. Lee asked, “What happens to the ablations that DON’T fail? And, more importantly, how many succeed? Without that information, the merits or limitations of alcohol ablation are unknown as well.” As for study participants from outside institutions, the study did not quantify if those institutions perform a large number of alcohol ablations and their success rates.

Dr. Lee also noted that the study included “only” 31 patients who failed alcohol ablation. “If the number of surgical procedures is 1,500, this is very low, even if many surgeries occurred before the development of ablation,” he said.

A larger, head-to-head, randomized comparison that evaluates quality of life and recovery time would answer questions about the risks facing patients who had previous alcohol septal ablation, Dr. Lee said. In the meantime, in an institution with less surgical experience, percutaneous alcohol septal ablation may be the wise choice, he said. And patients will always gravitate to the least invasive option. “The fact is,” Dr. Lee concluded, “they might be right.”

Dr. Lee is a professor of surgery at St. Louis University, Center for Comprehensive Cardiovascular Care.



How patients with hypertrophic obstructive cardiomyopathy who have already undergone alcohol septal ablation fare after going on to have surgical septal myectomy has been a matter of speculation and conjecture among cardiac surgeons for years, so a team of investigators set out to evaluate the outcomes among those patients.

What they found was that patients with a history of alcohol septal ablation may have an increased risk of cardiac death and complications after they have transaortic septal myectomy later on instead of just having septal myectomy as the primary procedure. In the Journal of Thoracic and Cardiovascular Surgery, Dr. Eduard Quintana of the University of Barcelona and the Mayo Clinic in Rochester, Minn., and coauthors reported that their findings support the use of surgical septal myectomy as the preferred treatment for septal reduction therapy for hypertrophic obstructive cardiomyopathy (HOCM) (J. Thorac. Cardiovasc. Surg. 2014 [doi:10.1016/j.jtcvs.2015.03.044]).

This small study evaluated 31 patients who had a failed alcohol septal ablation and then underwent septal myectomy and compared them to a group of 62 patients who had a septal myectomy only for HOCM. A total of 28 of the failed septal ablation patients had one such previous procedure and three had two or more percutaneous procedures before undergoing surgical septal myectomy. Study outcomes were cardiac death, advanced heart failure, and placement of an implantable cardioverter defibrillator (ICD). The study was conducted at the Mayo Clinic.

Percutaneous alcohol septal ablation utilizes injection of ethanol to correct left ventricular outflow tract obstruction (LVOT) in hypertrophic cardiomyopathy. Dr. Quintana and his coauthors reported that despite the percutaneous nature of alcohol septal ablation, its incidence of death and morbidity are not lower than surgical myectomy. They also reported that some countries are using alcohol ablation exclusively for septal reduction in HOCM. The rate of recurrence of severe symptoms after septal ablation is 20%, Dr. Quintana and his colleagues pointed out. “Thus, a sizeable proportion of patients having alcohol septal ablation may require transaortic septal myectomy for relief of LVOT, and outcome of such patients may be impaired,” they reported.

The 31 prior-ablation patients had a three times higher rate of implanted ICDs (32% vs. 11%), more arrhythmias (43% vs. 13% based on preoperative Holter monitoring), and a 12 times higher rate of postoperative complete heart block (19.4% vs. 1.6%). The prior–septal ablation group progressed to advanced heart failure at twice the rate, 22.5% at an average follow-up of 3.2 years, compared with about 10% in the primary septal myectomy group.

The authors also reported the 31 prior-ablation patients had significantly higher rates of interstitial and endocardial fibrosis – 70% vs. 26% and 87% vs. 67%, respectively.

“Our data contributes to accumulating evidence that the infarction induced by alcohol septal ablation may have adverse and unexpected consequences,” Dr. Quintana and his colleagues said.

However, the authors also acknowledged that one limit of their study was that it could not identify the overall failure rate of alcohol septal ablation among the larger patient population that underwent the procedure – “the inability to clearly define the denominator.” Nineteen of the 31 prior-ablation subjects had been referred from other institutions.

Coauthor Dr. Anna Sabata-Rotes received funding from Fundacia La Caxia, Barcelona. The other authors had no relationships to disclose.

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