Subpleural Perfusion as a Predictor for a Poor Surgical Outcome in Chronic Thromboembolic Pulmonary Hypertension

BackgroundSmall vessel disease is a major determinant of poor outcome after pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension (CTEPH). Out-of-proportion pulmonary vascular resistance (PVR) may indicate the presence of small vessel disease, but it is a very subjective evaluation. We investigated poor subpleural perfusion as a marker for small vessel disease and assessed its association with disease severity and surgical outcome of CTEPH.MethodsWe assessed the subpleural perfused area in the capillary phase of pulmonary angiography in 104 consecutive patients, including 45 who underwent surgery, and then divided the patients into either the well-perfused group (the subpleural space in at least one segment was well perfused [n = 75]) or the poorly perfused group (subpleural spaces were either unperfused or minimally perfused in all segments [n = 29]). We compared the pulmonary hemodynamics, degree of distal thrombi, and surgical outcome between these two groups.ResultsThe poorly perfused group had significantly higher PVR (937 ± 350 dyne/s/cm5 vs 754 ± 373 dyne/s/cm5, P = .02) and more distal thrombi, resulting in fewer surgically treated patients (27.6% vs 49.3%, P = .04) compared with the well-perfused group. This group showed a higher surgical mortality (62.5% vs 2.7%) and higher postoperative PVR (656 ± 668 dyne/s/cm5 vs 319 ± 223 dyne/s/cm5, P = .04). Even in a multivariate analysis, poor subpleural perfusion was associated with surgical mortality.ConclusionsPoor subpleural perfusion in the capillary phase of pulmonary angiography might be related to small vessel disease and a poor surgical outcome of CTEPH.