Left atrial volume index as an independent determinant of pulmonary hypertension in patients with chronic organic mitral regurgitation.

Background: The common pathophysiological consequences of chronic mitral regurgitation (MR) are left atrial (LA) remodeling/dilatation and pulmonary hypertension (PH). We aimed to study the association between LA volume (LAV) and PH in patients with chronic organic MR.

Methods: We prospectively studied 154 patients (age 55.0 ± 16.4 years, 39.6 % female) with isolated moderate to severe chronic organic MR. Severity of MR was assessed using proximal isovelocity surface area method. LAV was assessed using the area-length biplane method. PH was defined as pulmonary artery systolic pressure > 50 mmHg.

Results: Ruptured chordae and flail leaflets were the most common etiology of MR (53.2 %). Severe MR (effective regurgitant orifice area (EROA) > 40 mm(2)) was described in 123 (79.9 %) patients. Dyspnea, history of heart failure and atrial fibrillation was reported in 37.7 %, 20.1 % and 29.4 % of patients, respectively. Left ventricular (LV) ejection fraction was 68.1 ± 5.9 %. LAV index and EROA were 67.1 (24.7-391.3) ml/m(2)and 60.3 (10.5-250.9) mm(2), respectively. Age, presence of atrial fibrillation, EROA, LV end-systolic and end-diastolic volume, LV mass index, LAV index and tricuspid annular plane systolic excursion were all factors univariately associated with PH. In multiple logistic regression analysis, age (OR = 1.03, 95 % CI: 1.001-1.06, p = 0.04), EROA (OR = 1.02, 95 % CI: 1.003-1.03, p = 0.017) and LAV index (OR = 1.01, 95 % CI: 1.002-1.02, p = 0.021) were independently associated with PH.

Conclusions: In patients with chronic organic MR, a significant association exists between LAV index and PH. Age, the severity of MR as assessed by EROA, and LAV index are the independent determinants of PH.