Histopathological multiple recanalized lesion is critical element of outcome after pulmonary thromboendarterectomy

Pulmonary thromboendarterectomy (PEA) is a curative therapy for chronic thromboembolic pulmonary hypertension (CTEPH), but the postoperative mortality remains unsatisfactory (4-10%). Residual pulmonary hypertension is the most common cause of perioperative death. Although PEA specimens seem to contain lesions responsible for hemodynamic improvement, relevant histopathological findings have still to be identified. The aim of this study was to identify histopathological findings that predict postoperative residual pulmonary hypertension after PEA. PEA specimens obtained from 51 consecutive patients with CTEPH were histopathologically assessed. The patient characteristics and disease location were reviewed by medical records. The associations with residual pulmonary hypertension were analyzed. The mean values of preoperative and postoperative vascular resistance (PVR) were 1142 ± 454 and 496 ± 368 dynes•sec/cm ^-5, respectively. Twenty of 51 patients (39%), including 2 patients who died, continued to have residual pulmonary hypertension (PVR ≥ 500 dynes•sec/cm ^-5). Statistical tests indicated that male, proximal disease type and the presence of histopathological multiple recanalized thrombus were associated with good surgical outcome (PVR < 500 dynes•sec/cm-5). The positive and negative predictive values for surgical outcome estimated by the presence of multiple recanalized lesions were higher than the values estimated by proximal disease type (85% and 88% versus 73% and 71%, respectively). Moreover, the number of multiple recanalize lesions was significantly correlated to the reduction in PVR (P = 0.03). The presence of histopathological multiple recanalized lesions was significantly associated with a decrease in PVR after PEA. Histopathological study may be a potent diagnostic strategy for accurately predicting surgical outcome in the early perioperative period.