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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