Plasma brain natriuretic peptide as a biomarker for haemodynamic outcome and mortality following pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension

OBJECTIVES: In chronic thromboembolic pulmonary hypertension (CTEPH), right ventricular (RV) dysfunction is associated with increased morbidity and mortality following pulmonary endarterectomy. Plasma brain natriuretic peptide (BNP) levels were previously shown to correlate with RV (dys)function. We hypothesized that BNP can be used as a non-invasive biomarker to identify patients at 'high risk' for postoperative morbidity and mortality. METHODS: We studied the postoperative outcome in 73 consecutive patients. Patients were divided into three groups based on previously determined cut-off levels: BNP < 11.5, indicating normal RV function (ejection fraction [EF] >= 45%), BNP > 48.5 pmol/l, indicating RV dysfunction (right ventricular ejection fraction < 30%) and BNP 11.5-48.5 pmol/l. Postoperative 'bad outcome' was defined as the presence of either residual pulmonary hypertension (PH) or (all-cause) mortality. RESULTS: Plasma BNP > 48.5 pmol/l was shown to be an independent predictor of 'bad outcome'. Compared with BNP < 11.5 pmol/l, BNP > 48.5 pmol/l identified patients at higher risk for (all-cause) mortality (17 vs 0%; P = 0.009) and residual PH (56 vs 20%; P < 0.004). Also, the durations of mechanical ventilation and intensive care unit stay were significantly longer in patients with BNP > 48.5 pmol/ml. CONCLUSIONS: Plasma BNP levels may be of use as a non-invasive biomarker reflecting RV dysfunction, next to other well-recognized (invasive) parameters, for better preoperative risk stratification of CTEPH patients.