Early improvement in left ventricular diastolic function after relief of chronic right ventricular pressure overload

Abstract

Chronic right ventricular pressure overload is associated with left ventricular diastolic dysfunction. Whether or not an abrupt reduction in pulmonary artery pressure in patients with chronic pulmonary hypertension results in early improvement of left ventricular diastolic function is unknown. To asess this, the Doppler indexes of left ventricular diastolic function and echocardiographic measures of left ventricular volume were analyzed in 22 patients (age, 41 ± 14 years, mean ± SD) before and within 1 week after pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension. Mean duration of cardiopulmonary symptoms was 37 months (range, 4 months to 9 years). After operation, mean pulmonary artery pressure and pulmonary vascular resistance decreased (50 ± 13 to 29 ± 9 mm Hg and 904 ± 654 to 283 ± 243 dynes · sec/m5, respectively, both p < 0.001), pulmonary artery wedge pressure was unchanged (11 ± 5 to 12 ± 5 mm Hg), and cardiac index increased (2.0 ± 0.5 to 2.8 ± 0.7 l/min/m2, p < 0.001). Left ventricular end-diastolic volume and stroke volume increased significantly (58.5 ± 18.0 to 76.6 ± 25.0 ml and 30.3 ± 12.3 to 41.8 ± 12.5 ml, respectively, both p < 0.001) after surgery. Doppler measures of left ventricular diastolic function including peak early velocity of mitral inflow, deceleration of early filling, and early to late peak flow velocity ratio increased with surgery (48 ± 20 to 79 ± 24 cm/sec, p < 0.001, 2.6 ± 1.4 to 4.2 ± 1.8 m/sec2, p < 0.002, and 1.04 ± 0.42 to 1.67 ± 0.60, p < 0.001, respectively), whereas peak atrial velocity did not change significantly (48 ± 10 to 49 ± 9 cm/sec). Furthermore, the indexes of left ventricular relaxation correlated with the end-systolic position of the interventricular septum as assessed by two-dimensional echocardiography (all p < 0.001). Thus, Doppler-derived indexes of left ventricular diastolic function improve markedly early after pulmonary thromboendarterectomy in patients with pulmonary hypertension despite long-standing symptoms. The changes in these indexes of left ventricular diastolic function, which correlate with changes in the position of the interventricular septum and occur in the setting of increases in left ventricular volume, suggest that abnormal left ventricular diastolic function seen in right ventricular pressure overload is a consequence of the right-left ventricular interaction and is mediated in large part through the interventricular septum.