Plasma brain natriuretic peptide as a noninvasive marker for efficacy of pulmonary thromboendarterectomy

Background. Plasma brain natriuretic peptide (BNP), a cardiac hormone secreted mainly by the cardiac ventricles, has been shown to increase in proportion to the degree of cardiac overload. However, whether plasma BNP may serve as a marker for the efficacy of pulmonary thromboendarterectomy in patients with chronic thromboembolic pulmonary hypertension remains unknown. Methods. Plasma BNP level was measured in 34 patients with chronic thromboembolic pulmonary hypertension before and 1 month after pulmonary thromboendarterectomy. Right heart catheterization was also performed before and 1 month after the operation. Results. Preoperative plasma BNP level was significantly elevated in patients with chronic thromboembolic pulmonary hypertension compared with control patients (246 ± 40 vs 13 ± 2 pg/mL; p< 0.001; N = 34) and was positively correlated with total pulmonary resistance (r = 0.57; p< 0.001). After pulmonary thromboendarterectomy, plasma BNP level in survivors markedly decreased (220 ± 31 to 54 ± 9 pg/mL; p< 0.001; N = 32) in association with a reduction of total pulmonary resistance (15.6 ± 1.0 to 4.5 ± 0.3 Wood units; p< 0.001). The change in plasma BNP level was closely correlated with that in total pulmonary resistance (r = 0.63; p< 0.001). Importantly, a sustained elevation of plasma BNP (≥ 50 pg/mL) indicated the presence of residual pulmonary hypertension (≥ 5 Wood units) after operation (sensitivity = 73%; SPECIFICITY = 81%). Conclusions. Plasma BNP level was strongly associated with the severity of pulmonary hypertension in patients with chronic thromboembolic pulmonary hypertension and thereby may serve as a noninvasive marker for the efficacy of pulmonary thromboendarterectomy.