Association Between Three-Dimensional Left Ventricular Outflow Tract Area and Gradients After Myectomy in...

Area of Science:

• Cardiology
• Cardiovascular Surgery
• Medical Imaging

Background:

• Hypertrophic obstructive cardiomyopathy (HOCM) presents a significant challenge in cardiac surgery.
• Septal myectomy is a key surgical intervention for HOCM, aiming to relieve left ventricular outflow tract (LVOT) obstruction.
• Assessing surgical success and predicting residual obstruction are crucial for patient outcomes.

Purpose of the Study:

• To investigate the correlation between intraoperative three-dimensional (3D) left ventricular outflow tract (LVOT) cross-sectional area and pressure gradients post-septal myectomy.
• To determine if LVOT area is a determinant of surgical success in hypertrophic cardiomyopathy patients.

Main Methods:

• Retrospective review of perioperative data from 67 hypertrophic obstructive cardiomyopathy patients.
• Intraoperative transesophageal echocardiography (TEE) for pressure gradient and 3D LVOT area assessment.
• Transthoracic echocardiography for postoperative gradient evaluation.

Main Results:

• The LVOT area significantly increased post-myectomy (average 1.883 cm²).
• A significant inverse correlation was found between the increase in LVOT area and intraoperative transesophageal pressure gradients (r = -0.32, p = 0.01).
• Predictors of high residual gradients included preoperative transesophageal gradient, postoperative transesophageal LVOT area, and mitral regurgitation.

Conclusions:

• Intraoperative 3D LVOT area measured by TEE after septal myectomy correlates with immediate postoperative transesophageal pressure gradients.
• Patients with persistent elevated transthoracic gradients at follow-up had smaller intraoperative TEE LVOT areas and higher transesophageal gradients.
• Immediate transesophageal pressure gradients post-myectomy showed poor correlation with long-term resting transthoracic gradients.