Thursday, August 2, 2018

Alcohol Septal Ablation for Obstructive HCM



Alcohol Septal Ablation for Obstructive HCM

Debabrata Mukherjee, MD, FACC

The following are key counterpoints to remember about the use of alcohol septal ablation (ASA) for obstructive hypertrophic cardiomyopathy (HOCM):

Hypertrophic cardiomyopathy (HCM) is an inheritable cardiac disease with a prevalence of 1 in 500 persons, leading to millions of persons affected worldwide.

The management of drug-refractory symptoms due to HOCM has long been debated, and is primarily centered on the choice between surgical myectomy ASA.

On one side, surgical myectomy is put forth as the most effective and safe therapy for relief of left ventricular outflow tract (LVOT) obstruction, and alcohol ablation is described as less efficacious and associated with increased risk of pacemaker dependency, as well as a scar that is potentially proarrhythmic in a vulnerable patient.

On the other side of the argument, alcohol ablation is presented as less invasive and thus patient-preferred. The favorable outcomes of surgical myectomy are noted to be mainly from experienced centers, and the low number of these centers limits accessibility for those who may be myectomy candidates.

Comparative studies on septal reduction therapy in HCM with long-term survival have emerged over the last several years, but they remain largely limited to single centers or small registries that are subject to selection bias.

For ASA, the clinical effectiveness may be comparable to surgical myectomy when there is careful patient selection, one or more appropriate septal perforator arteries, and proper technical performance.

Optimization of outcomes with ASA is essential, as residual LVOT obstruction after ablation is associated with a higher likelihood of death, not just a higher likelihood of persistent symptoms. It should be noted that there is a learning curve to the procedure.

However, without certainty about the long-term effects of ASA, there remains the known higher rates of pacemaker therapy, residual symptoms, and need for repeat intervention.

Overall, ASA and surgical myectomy are both highly effective therapies in appropriately selected patients. However, the data limitations continue to foster the ongoing controversy regarding the most appropriate therapy for drug-refractory symptoms due to HOCM.

The establishment of a mandatory, national registry for septal reduction therapy would help to promote standards of care, help further define centers of expertise, and facilitate public reporting.


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