Comparison of Early and Mid-Term Outcomes After Classic and Modified Morrow Septal Myectomy in Patients with Hypertrophic Obstructive Cardiomyopathy.

Introduction: The aim of our study is to compare the early and mid-term outcomes of patients with hypertrophic obstructive cardiomyopathy who underwent classic and modified Morrow septal myectomy.

Methods: Between 2014 and 2019, 48 patients (24 males; mean age 49.27±16.41 years) who underwent septal myectomy were evaluated. The patients were divided into two groups - those who underwent classic septal myectomy (n=28) and those who underwent modified septal myectomy (n=20).

Results: Mitral valve intervention was higher in the classic Morrow group than in the modified Morrow group, but there was no significant difference (P=0.42). Mortality was found to be lower in the modified Morrow group than in the classic Morrow group (P=0.01). In both groups, the mean immediate postoperative gradient was significantly higher than the mean of the 3rd and 12th postoperative months. The preoperative and postoperative gradient difference of the modified Morrow group was significantly higher than of the classic Morrow group (P<0.001).

Conclusion: Classic Morrow and modified Morrow procedures are effective methods for reducing left ventricular outflow tract obstruction. The modified Morrow procedure was found to be superior to the classic Morrow procedure in terms of reducing the incidence of mitral valve intervention with the reduction of the left ventricular outflow tract gradient.