Safety and Immediate Efficacy of Pulmonary Thromboendarterectomy for Chronic Thromboembolic Disease

Abstract

Background: Chronic thromboembolic disease (CTED) is characterized by pulmonary vascular thromboembolic occlusions without elevation in pulmonary artery pressures or pulmonary vascular resistance at rest. Many patients have dyspnea on exertion despite normal resting hemodynamics and symptomatic improvement after pulmonary thromboendarterectomy surgery. We hypothesize that the safety and efficacy of pulmonary thromboendarterectomy in CTED will be similar to that in chronic thromboembolic pulmonary hypertension (CTEPH), which currently has a better characterized risk-benefit profile.

Methods: Patients who underwent pulmonary thromboendarterectomy for CTED from 2009 through 2022 had preoperative and postoperative pulmonary hemodynamics and postoperative course (n = 163) compared with a reference CTEPH cohort who underwent pulmonary thromboendarterectomy from 2017 to 2022 (n = 870). Preoperative rest hemodynamics were compared with both preoperative exercise and postoperative rest hemodynamics in patients with CTED who had measurements for all 3 conditions.

Results: The CTED cohort had 99 patients with complete preoperative rest, preoperative exercise, and postoperative hemodynamic measurements. Mean pulmonary artery pressure, pulmonary vascular resistance, and pulmonary artery compliance all changed abnormally with preoperative exercise but improved after surgery (21 [SD, 4], 36 [SD, 10], 18 [interquartile range {IQR}15-21] mm Hg; 175 [SD, 87], 205 [SD, 149], 126 [SD, 55] dyne·s·cm^-5; 3.6 [IQR, 3.1-4.4], 2.7 [IQR, 2.1-3.6], 4.8 [IQR, 3.7-6.0] mL/mm Hg; preoperative rest, exercise, and postoperative for mean pulmonary artery pressure, pulmonary vascular resistance, and compliance; P < .001 for all comparisons, mean [SD] if normally distributed, otherwise median [IQR]). CTED patients had no in-hospital mortality and shorter hospital and intensive care unit lengths of stay (P < .001 for both) compared with the CTEPH cohort.

Conclusions: Pulmonary thromboendarterectomy is safe and well-tolerated in patients with CTED, improving pulmonary hemodynamics and pulmonary artery compliance.

FIGURE 1

Change in pulmonary artery compliance (C_PA) and pulmonary vascular resistance (PVR) after pulmonary thromboendarterectomy (PTE). Improvement in chronic thromboembolic disease (CTED) patients (white dots) is primarily through increased C_PA, whereas in chronic thromboembolic pulmonary hypertension (CTEPH) patients (black dots) it is primarily through reduction of PVR, though there is also reduction in C_PA.

FIGURE 2

Preoperative hemodynamic changes with exercise in patients with chronic thromboembolic disease. Each line represents an individual patient. Some patients had abnormal changes in hemodynamics with exercise, plotted in red, whereas all others are plotted in black. (A) Slope of mean pulmonary artery pressure (mPAP)/cardiac output (CO) between rest and exercise. The slope was >3 mm Hg/min/L in 63% of patients. (B) Pulmonary artery compliance (C_PA) at rest and exercise before pulmonary thromboendarterectomy (PTE). An abnormal decrease in C_PA occurred with exercise in 78% of patients. (C) Peripheral vascular resistance (PVR) at rest and exercise before PTE. An abnormal increase in PVR with exercise occurred in 74% of patients. (D) Resistance-compliance (RC) time constant at rest and exercise. An abnormal increase in RC time constant with exercise was documented in 41% of patients.