Introduction: In the international literature, transaor-tic septal myectomy is regarded as the gold-standard treatment for patients with obstructive hypertrophic cardiomyopathy (HCM) and drug-refractory symp-toms. However, the best results are obtained by few surgeons with extensive experience with this operation at a small number of HCM referral centers in North America and Europe. Offering the best invasive treat-ment for left ventricular (LV) outflow obstruction at the growing number of operative HCM candidates re-mains a major challenge.

Objective: In the present study, we report our experi-ence with developing a surgical program for the myec-tomy operation over a period of 4 years at a single cen-ter.

Methods: Each of 64 consecutive HCM patients with drug-refractory symptoms who underwent transaortic surgical treatment of LV outflow obstruction, in the ab-sence of additional surgical procedures, at our center between May 2015 and April 2019 were enrolled in the study. Age: range 21 to 75, mean 51 ± 3 years; NYHA class III-IV symptoms: 34 of 64 patients (53%); maxi-mal septal thickness: range 14 to 35, mean 23 ± 2 mm; resting or provoked gradient: range 54 to 140, mean 77 14 mmHg; moderate-to-severe/severe mitral valve (MV) regurgitation: 21 (33%). A septal myectomy was performed through an aortotomy and the muscle ex-cision went beyond the point of mitral-septal contact, fibrotic and retracted secondary chordae of the anteri-or MV leaflet were cut selectively as well as, when ne-cessary, muscular aberrant bundles.

Results: Deaths at surgery and during hospitalization: none; iatrogenic septal defect: none. MV replacement: none; postoperative NYHA Class III-IV symptoms: none of the study patients; maximal septal thickness: 17 ± 3 mm, range from 13 to 23 mm; resting LV outflow gradient: 12 ± 4 mm Hg, range from 5 to 28 mmHg; moderate-to-severe/severe MV regurgitation: 2 pati-ents (3%).

Conclusions: Transaortic cutting of retracted secon-dary MV chordae and papillary muscle mobilization, by moving the MV apparatus away from the outflow tract, contributed to abolish the outflow gradient and MV regurgitation in our study patients undergoing septal myectomy. This approach was associated with a particularly favorable clinical outcome in patients with HCM. On the basis of our experience, we believe that the adoption of a similar program could increase the number of cardiovascular surgeons capable of offering an adequate treatment of LV outflow obstruction to the many and often young patients with HCM who are eli-gible for invasive abolition of the outflow gradient.