Material and methods
This study was a comparative cross-sectional study conducted at a tertiary care hospital in North India in which 120 subjects including 80 patients with isolated severe MS (MVA ≤1.5 cm2) with pulmonary hypertension between 18-40 years of age who were in sinus rhythm and 40 age matched healthy controls were enrolled from cardiology outpatient department. Patients with moderate to severe mitral regurgitation or other significant valve involvement and co-morbidities like hypertension, diabetes mellitus, coronary artery disease, overt LV systolic dysfunction were excluded. Philips EpiQ 7C echocardiography system with 2.4 MHz transducer was used for recording echocardiographic images. The study was carried out after prior approval from the institutional ethical committee and written informed consent was obtained from all the participants.
For all subjects, standard two-dimensional (2D), M-mode and Doppler echocardiograms were obtained according to the American Society of Echocardiography guidelines.11 Baseline measurements included were LA dimension, LV internal dimension in diastole (LVIDd) and in systole (LVIDs) and LV ejection fraction (LVEF). MVA ≤1.5 cm2 (by planimetry) was considered to define severe MS and MVA <1.0 cm2 defined very severe MS.13 Peak diastolic gradient (PG) and mean diastolic gradient (MG) across the mitral valve was calculated by continuous wave (CW) Doppler tracing. Apical four chamber (A4C) and apical two chamber (A2C) views were recorded in all the patients. Right ventricle systolic pressure (RVSP) was measured from tricuspid regurgitation jet velocity by CW Doppler after ruling out primary involvement of tricuspid and pulmonary valve.14 Three consecutive cardiac cycles were recorded and averaged.
Pulmonary hypertension (PH) was graded based on peak RVSP as mild 36-45 mm Hg, moderate 46-60 mm Hg and severe if >60 mm Hg.15 Patients were classified according to the New York Heart Association (NYHA) functional classification. Patients in NYHA class IV were not included because all the patients recruited were from OPD visits and were ambulatory.