Background: Left ventricular dynamic outflow tract obstruction (LVOTO) is usually seen in patients with left ventricular hypertrophy (LVH) and systolic anterior motion of the anterior mitral valve leaflet. It is not known whether the increased sub aortic blood flow velocities may generate or accelerate aortic valve (AV) disease over time.
Purpose: To assess the development of aortic stenosis (AS) and/or significant aortic regurgitation (moderate to severe or severe) in patients with LVH and significant LVOTO (Group 1) vs. patients with LVH but no LVOTO (Group 2) over time.
Methods: Single center, retrospective analysis of patients diagnosed with hypertrophic cardiomyopathy (HCM) that had LVH (wall thickness ≥ 13mm), normal LV systolic function and echocardiographic follow up of ≥ 48 months. Those with AS (valvular peak gradients≥25mmHg) or ≥ moderate aortic regurgitation at baseline echocardiogram were excluded. Group 1 consisted of patients with significant LVOTO (≥ 30mmHg LVOT gradients) at baseline echocardiogram whether in Group 2 patients did not have significant LVOTO in any of the echocardiograms.
Results: There were 120 patients in the study, 74 in group 1 (maximal resting LVOT gradient 39mmHg and 81mmHg with provocation) and 46 in group 2. Age and gender did not significantly differ between groups (60.7 and 63.4 years; 59% and 43% male, respectively) but maximal septal wall thickness was significantly increased in group 2 vs. group 1 (19.5mm vs. 16.5mm; p=0.007). Follow up time in months was 92 and 106 respectively (p=0.36). At the end of follow-up, 13 patients developed AS (10.8%). 10 patients in group 1 (1 with severe and 2 with moderate AS) and 3 patients in group 2 (mild stenosis), (p=0.37). Only 1 patient developed significant aortic regurgitation in group 1 and none in group 2.
Conclusion: Although there was no significant difference in the development of AS in patients with vs. those without LVOTO, interestingly, we found that a relatively high proportion of patients with HCM, especially those with LVOTO (13.5%) develop AS over time. Larger studies are required to assess the significance of this finding.
