Prevalence of Coronary Artery to Pulmonary Artery Collaterals in Patients with Chronic Thromboembolic Pulmonary Hypertension: Retrospective Analysis from a Single Center.

Background: Our aim was to determine the prevalence of coronary artery - pulmonary artery collaterals in patients with chronic thromboembolic pulmonary hypertension (CTEPH) by retrospectively evaluating coronary angiograms of eligible consecutive patients who had undergone pulmonary endarterectomy (PEA). We also aimed to evaluate predictors and potential clinical associates of these collaterals.

Methods: Coronary angiograms of 83 consecutive CTEPH patients who had undergone coronary angiography before PEA operation between January 1, 2012 and June 1, 2015 were retrospectively evaluated for presence of coronary artery - pulmonary artery collaterals. Medical records of all patients were also retrospectively reviewed for demographic information, cardiovascular risk factors, preoperative right heart catheterization reports, operation reports, and follow-up data. Data of CTEPH patients with coronary artery - pulmonary artery collaterals were compared with data of CTEPH patients without such collaterals.

Results: There were 15 patients (18.1%) with definite and 4 patients (4.8%) with probable coronary artery - pulmonary artery collaterals among the study population. CTEPH patients with collaterals had higher preoperative pulmonary artery pressures, higher pulmonary vascular resistance (PVR) and lower cardiac index values compared with CTEPH patients without collaterals. However, CTEPH patients with collaterals displayed higher amount of reduction in PVR after PEA compared with patients without collaterals. There were no significant differences between groups regarding incidence of reperfusion injury or mortality.

Conclusion: Prevalence of coronary artery - pulmonary artery collaterals seems to be increased in our CTEPH patients compared with the general population. The presence of coronary artery - pulmonary artery collaterals is often combined with proximal disease with the possibility of increased reduction of PVR after PEA operation.