Subpleural perfusion as a predictor for a poor surgical outcome in chronic thromboembolic pulmonary hypertension.

BACKGROUND: Small 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.

METHODS: We 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.

RESULTS: The poorly perfused group had significantly higher PVR (937 ± 350 dyne/s/cm(5) vs 754 ± 373 dyne/s/cm(5), 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/cm(5) vs 319 ± 223 dyne/s/cm(5), P = .04). Even in a multivariate analysis, poor subpleural perfusion was associated with surgical mortality.

CONCLUSIONS: Poor subpleural perfusion in the capillary phase of pulmonary angiography might be related to small vessel disease and a poor surgical outcome of CTEPH.