Alcohol septal ablation: in which patients and why?

Abstract

At present, surgical septal myectomy is regarded as the "gold standard" treatment for most patients with obstructive hypertrophic cardiomyopathy (HCM) and drug-refractory symptoms. However, the best results are obtained by those surgeons who have extensive experience with this operation at a small number of referral centers. In the mid-1990s, percutaneous alcohol septal ablation was introduced as an alternative to myectomy to reduce LV outflow gradient and heart failure symptoms in patients with obstructive HCM. However, certain features of alcohol ablation limit its applicability to carefully selected patients.Because this procedure involves the injection of 1-4 mL of 96% ethanol into a septal perforator of the left anterior coronary artery to produce a myocardial infarction (with septal thinning, outflow tract widening and gradient reduction), alcohol ablation is limited by the size and distribution of the septal perforator branches. In addition, rich blood supply from other septal branches not occluded by the balloon and from the posterior descending coronary artery may restrict myocardial ischemia to portions of the septum that do not contribute to outflow obstruction. Septal hypertrophy may be either mild or particularly marked, and abnormalities of mitral valve apparatus may also play a major role in outflow obstruction. When such features are present, alcohol-induced septal thinning is unlikely to significantly reduce the gradient. In addition, persisting uncertainties regarding the risk for ventricular tachyarrhythmias after alcohol ablation suggest this procedure should be limited to patients of advanced age, patients at unacceptable operative risk due to comorbidities, or those with strong aversion to surgery. Further progress in the treatment for patients with obstructive HCM and severe refractory symptoms will come from assuring proper patient selection for alcohol septal ablation, as well as increasing the number of surgeons and centers experienced in performing septal myectomy. PerspectiveIn patients with hypertrophic cardiomyopathy (HCM), left ventricular (LV) outflow obstruction with a pressure gradient between the LV outflow tract and aorta is caused by systolic anterior motion of the mitral valve against the septum (1), and is identified at rest or with physiologic exercise in about 70% of patients evaluated at tertiary referral centers (2). Obstruction to LV outflow obstruction is associated with mitral valve regurgitation, disabling heart failure symptoms and increased cardiovascular mortality (3,4). For almost 50 years, transaortic septal myectomy has represented the standard surgical approach for the treatment of patients with obstructive HCM and severe symptoms refractory to medical treatment (1,5-7).In the mid-1990s, percutaneous alcohol septal ablation was introduced as an alternative to surgical myectomy to reduce the LV outflow gradient and heart failure symptoms in patients with obstructive HCM (8). This catheterbased procedure, made attractive by its less invasive nature, was rapidl...

Ventricular tachycardia and heart failure in a patient of mid‑ventricular obstructive hypertrophic cardiomyopathy with apical aneurysm: A case report

“…For HCM with subaortic obstruction and severe drug-refractory symptoms, surgical septal myectomy should be the gold standard for septal reduction therapy in centers with comprehensive experience (15). Alcohol septal ablation (ASA) has been proposed as a less invasive alternative to surgical myectomy in patients with advanced age, those that had previously received a pacemaker or defibrillator, as well as those with significant comorbidities and a strong aversion to surgery (16,17). Seggewiss and Faber (18) have reported on a case of mid-ventricular obstruction, which responded favorably to alcohol ablation.…”

Predictors of long‐term outcome after septal myectomy in symptomatic hypertrophic obstructive cardiomyopathy patients with previous alcohol septal ablation and residual obstruction

“…The effects are limited by anatomical morphology, perforator artery distribution, and collateralization. 14 22 Turina et al 23 first reported development of CHF associated with left ventricular dilatation at 8 years after surgical septal myectomy. In fact, previous studies found global strain in patients with HCM was significant reduced compared with healthy subjects despite normal left ventricular function as assessed by standard criteria such as LVEF or fraction shortening, suggesting the presence of a global subclinical systolic dysfunction.…”

“…Thus, worldwide practiced ASA procedures have unexpectedly and paradoxically increased the number of septal myectomy to some extent. 14 Nevertheless, surgical treatment for this subgroup of patients can be very tough and challenging, and regarding studies are scarce.…”

Gradient variability in hypertrophic cardiomyopathy: New insights from computer‐assisted, high fidelity, rest and exercise hemodynamic analysis

“…LVOT pressure gradients are most often measured noninvasively by Doppler, but in some patients with eccentric mitral regurgitation accurate measurement is challenging and invasive measurement may be required. Invasive LVOT gradients are also evaluated during alcohol septal ablation procedures . Invasive exercise LVOT gradient measurement is impractical for most catheterization laboratories.…”

“…Invasive LVOT gradients are also evaluated during alcohol septal ablation procedures. 9,10 Invasive exercise LVOT gradient measurement is impractical for most catheterization laboratories. Invasive provocation methods include Valsalva maneuvers, isoproterenol infusion, and the postpremature ventricular contraction (PVC) responses to induced or spontaneous ventricular ectopy.…”