Abstract 2636: Septal Myectomy after Previous Septal Artery Ablation
Introduction: Septal myectomy is the gold standard for relieving LVOT obstruction in HOCM. However, septal artery ablation has recently been shown to successfully relieve LVOT obstruction by creating a localized basal septal infarct. We identified 12 patients who failed septal artery ablation and subsequently underwent septal myectomy. We examined reasons for septal artery ablation failure and surgical outcome of septal myectomy after prior septal artery ablation.
Methods: Between January 1999 and August 2005, 12 patients underwent septal myectomy after previously failed septal artery ablation. Angiograms during septal artery ablation, pre and post-operative echocardiographic data, hospital course and follow-up data were reviewed.
Results: Mean time between septal artery ablation and septal myectomy was 575 ± 672 days. Angiograms at time of septal artery ablation revealed abnormal coronary anatomy in 89% of patients. This included:
diminutive first septal arteries,
large septal artery coursing through to the apex requiring ablation of small branches,
origination of the first septal artery from a too distal location. SAM was present in 11 patients before septal myectomy and 4 postoperatively (p=0.002). Mitral regurgitation decreased from 3.08 to 1.33 (p=0.07) postoperatively, and importantly, mean LVOT gradient decreased from 85±20 mm Hg to 5±10 mm Hg postoperatively (p<0.0001). There was 1 early death due to multi-organ system failure. Follow-up was obtained in 9 of 11 early survivors. There was one late sudden death. Of the remaining 8 patients, all had improvement in symptoms with 5 in NYHA 1 and 3 in NYHA II. Mean LVOT gradient was 13 ± 16 mm Hg at follow-up. There was no evidence of SAM on follow-up echocardiography.
Discussion: Septal myectomy remains the gold standard for relief of LVOT obstruction. All patients in this study failed septal artery ablation because of a failure to ablate enough myocardium due to abnormal coronary anatomy in most cases. This is the first study to demonstrate specific situations in which septal artery ablation should potentially be avoided.