Assessment of safety and efficacy of Morrow septal myectomy and alcohol septal ablation in patients with obstructive hypertrophic cardiomyopathy: the results of a pilot randomized trial

Abstract

<p><strong>Aim.</strong> The aim of this randomized study was to evaluate the safety and efficacy of septal myectomy (SM) and alcohol septal ablation (ASA) in patients with an obstructive form of hypertrophic cardiomyopathy.<br /><strong>Methods.</strong> The study included 76 patients eligible for ASA and Morrow myectomy. The patients were divided into two equal groups: one for ASA (n = 38), the other for SM.<br />The primary endpoint (combined) was to assess the safety, which included 30-day complications after surgery (mortality, bleeding, tamponade, stroke, development of VT / VF) and the frequency of pacemaker/ICD implantation.<br />Secondary endpoints focused on the evaluation of pressure gradient (efficiency), repeated operations, clinical and functional indicators, volume and mass of the ablation zone and dissected infarction. Control observation period was 12 months.<br /><strong>Results.</strong> By the end of control observations, it was found out that SM is a safer technique as compared to ASA, the complication rate was 13 % and 47 % respectively (log-rank test p = 0.0021; Cox: HR 11.4 95% CI [1.52 -11.1] p = 0.005). No significant differences in early (30 days) postoperative complications were found (log-rank test p = 0.24; Cox: HR 2.52, 95% CI [0.48-12.9] p = 0.27). Rhythm disturbances requiring pacemaker implantation / ICD (log-rank test p = 0.0029; Cox: HR 95% CI 4.92 [1.06-22.74] p = 0.042) were the most common complication. In both groups, there was a significant reduction of the LVOT gradient, p <0.01. However, the residual gradient in the ASA group was significantly higher than that in the SM group, p <0.01. Clinical data of both groups were comparable in the long term. A significant correlation was observed between the dissected infarction volume and the degree of reduction in the LVOT gradient of the SM group, p = 0.01. No significant dependency of the ablation zone volume on the degree of reduction in the LVOT gradient was observed, p = 0.7.<br /><strong>Conclusion.</strong> Septal myectomy is a safe treatment for hypertrophic cardiomyopathy as compared to ASA. Alcohol septal ablation and SM are comparable in the effectiveness of LVOT gradient reduction. There is a dependence of the excised myocardium volume and the degree of reduction in the LVOT gradient during long-term follow-up of patients who underwent Morrow SM.</p><p>Received 5 August 2016. Accepted 2 September 2016.</p><p><strong>Funding:</strong> The study had no sponsorship. <br /><strong>Conflict of interest:</strong> The authors declare no conflict of interest.</p>