In some patients, septal hypertrophy extends more distally, from the subaortic portion of the septum to the midventricular portion. In these patients, classic transaortic surgical myectomy may not be effective in removing the midventricular obstruction, resulting in a suboptimal surgical outcome. These patients may present recurrence of symptoms and not have an improvement in the prognosis related to the treatment of hypertrophic cardiomyopathy, in some cases determining the need for reoperation. Since 2015, our Institute has used a surgical technique that allows us to improve transaortic exposure of the interventricular septum, using a probe with application of cryoenergy the hypertrophic portion of the septum is hooked and in this way the myectomy can be extended more distally, performing a more complete removal of the myocardium.

The aim of this study is to compare the results obtained with classical myectomy compared to myectomy performed with the aid of cryoenergy.

The primary endpoint is the comparison in terms of mortality between patients undergoing classical myectomy versus those undergoing cryoenergy-assisted myectomy.

Secondary endpoints are: extent of myectomy, persistence of residual left ventricular outflow tract obstruction, persistence of mitral regurgitation related to systolic anterior motion of the mitral leaflets, occurrence of ventricular defect, and need for PM implantation.

Inclusion Criteria:

• adult patients (≥ 18 years)
• meeting the clinical and echocardiographic criteria that made them candidates for isolated myectomy or in combination with other surgical procedures:
• LV outflow tract instantaneous peak gradient >50mmHg at rest or during stimulation
• interventricular septum >16mm,
• NYHA functional class III-IV, despite maximal medical therapy
• operated in San Raffaele Hospital with classic or cryo myectomy between 2015 and 2018.

Exclusion Criteria:

• extent of myectomy not reported in the operative report;
• left ventricular outflow tract gradient not reported in pre- or postoperative echocardiography.

Patients needing a myectomy due to obstructive hypertrophyc cardiomyopathy