Background Chronic thromboembolic pulmonary hypertension is surgically curable by pulmonary endarterectomy (PEA). It is unclear whether PEA impacts primarily steady state right ventricular afterload (ie, pulmonary vascular resistance (PVR)) or pulsatile right ventricular afterload (ie, pulmonary arterial compliance (C_PA)). Our objectives were to (1) quantify PEA specimens and measure the impact of PEA on PVR and C_PA in a structure/function study and (2) analyse the effects of haemodynamic changes on long-term survival/freedom of lung transplantation in an outcome study.

Methods Thrombi were laid out, weighed, photographed and measured. PVR, C_PA and resistance times compliance (RC-time) were assessed at baseline, within 4 days after PEA (‘immediately postoperative’) and 1 year after PEA, in 110 consecutive patients who were followed for 34.5 (11.9; 78.3) months.

Results Lengths and numbers of PEA specimen tails were inversely correlated with immediate postoperative PVR (p<0.0001, r=−0.566; p<0.0001, r=−0.580). PVR and C_PA normalised immediately postoperatively while RC-time remained unchanged. Immediate postoperative PVR was the only predictor of long-term survival/freedom of lung transplantation (p<0.0001). Patients with immediate postoperative PVR<590 dynes.s.cm⁻⁵ had better long-term outcomes than patients with PVR≥590 dynes.s.cm⁻⁵ (p<0.0001, respectively).

Conclusions PEA immediately decreased PVR and increased C_PA under a constant RC-time. However, immediate postoperative PVR was the only predictor of long-term survival/freedom of lung transplantation. Our study confirms the importance of a complete, bilateral surgical endarterectomy. Low PVR measured immediately postoperative predicts excellent long-term outcome.