Benefits of Surgery in Obstructive Hypertrophic Cardiomyopathy: Bring Septal Myectomy Back for European Patients

Bring Septal Myectomy Back for European Patients

Barry J. Maron; Magdi Yacoub; Joseph A. Dearani

Disclosures

Eur Heart J. 2011;32(9):1055-1058. 

In This Article

Septal Reduction: Myectomy vs. Ablation

Myectomy and ASA are competing (but not entirely equivalent) strategies, a point perhaps overlooked in the percutaneous era with non-surgical approaches to obstructive coronary artery disease, valvular heart disease, and septal defect closure. Despite early scepticism,[16,51] given the accumulated experience and published data over the last decade, ASA is deserving of an important role in the therapeutic armamentarium for severely symptomatic, drug-refractory patients with obstructive HCM. However, in accord with the American College of Cardiology and European Society of Cardiology consensus panel,[1] as well as other HCM experts,[2,3,13–17,19,20,32,34,52] ASA is most appropriate as an alternative to myectomy in selected patients who are not optimal surgical candidates, but is not the primary or sole treatment strategy for this subgroup.

Despite the fact that myectomy is an open-heart procedure and ASA is catheter-based, surgery has proved to be largely a 'pure' intervention rarely leaving behind implanted devices or a potentially arrhythmogenic substrate. In contrast, there are significantly more frequent conduction abnormalities with ASA, with up to 25% of patients receiving permanent pacemakers for complete heart block[3,7–11,20,32,33,36] or prophylactic implantable defibrillators for the risk of sudden death.[53,54] Furthermore, from the introduction of ASA, a concern emerged and has persisted regarding the risk for life-threatening sustained ventricular tachyarrhythmias in this patient population already prone to arrhythmia-related sudden death,[1–3,20,51–62] due to the alcohol-induced transmural infarction and scar (which occupies on average 10% of the LV wall and up to 30% of ventricular septum).[52,60]

On the basis of the available literature, after ablation about 10% of the patients experience important ventricular arrhythmias.[3,11,32,33,53,54,57,62] Since myectomy does not produce intramyocardial scarring, there is no evidence that surgery itself either increases arrhythmogenicity[15,39] or predisposes to systolic dysfunction.[63]

In a comparative study, ten Cate et al.[32] from the Thoraxcenter (Erasmus Medical Center) recently reported that long-term outcome and survival was four-fold less favourable after ASA compared with myectomy, with more than 20% of the patients incurring cardiovascular death, aborted cardiac arrest, and/or appropriate implantable defibrillator intervention, resulting in a high annualized event rate of 4.4% following ASA. These Rotterdam investigators recommended that myectomy should be the preferred intervention for obstructive HCM,[32] consistent with European Society of Cardiology guidelines.[1] Their data are also similar to those of the Massachusetts General Hospital[62] reporting a high annual event rate for ventricular tachycardia/fibrillation (VT/VF) of about 5%/year after ASA even in the presence of other conventional risk factors. Also, high-risk HCM patients with defibrillators post-ASA show an incidence of appropriate interventions for VT/VF of up to 10%/year,[32,53,54,59] substantially greater than in post-myectomy patients.[39] These concerns have suggested to many investigators the prudence of confining ASA to older patients with shorter periods of risk and avoiding this procedure in children and young adults.[1,3,20,51,57]

Unfortunately, a randomized trial to resolve the myectomy vs. ASA debate concerning long-term post-procedural outcome is not feasible due to a number of insurmountable obstacles,[64] i.e. heterogeneity and relative infrequency of HCM in general cardiological practice, as well as its low event rate. Therefore, the selection of patients for septal reduction intervention will continue to be based in large measure on clinical judgement and the available observational data.

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