Chronic thromboembolic pulmonary hypertension (CTEPH) is optimally treated by pulmonary thromboendarterectomy (PEA). Treatment effectiveness has been evaluated principally using single-center series. Data from the Society of Thoracic Surgeons Adult Cardiac Surgery Database were used to evaluate a volume-outcomes relationship for PEA.

Circulatory arrest procedures performed between 2012-2018 were identified through an STS-ACSD Participant User File. For descriptive purposes, total center procedural volume categories were computed: low (0-75^th percentile, <16); medium (76-95^th percentile, 16-100); high (>95^th percentile, >100). Mixed effect modeling was used to evaluate the effect of center procedural volume (modeled continuously) on operative mortality, adjusting for preoperative risk factors, with centers as a random effect.

There were 1,358 cases performed across 64 centers [n/N: low (49/172); medium (12/527); high (3/659)], with 42 centers performing <10 operations during the period. Procedural volume increased 2.6-fold between 2012-2018 (94 versus 339), with 79% of the change in volume accounted for by 4 centers. The mean (IQR) preoperative pulmonary artery systolic value was 74 mmHg (57-88), with no difference (p=0.55) by center volume categories. In unadjusted analysis, patients at high volume centers required fewer transfusions, had shorter ventilator and intensive care unit (ICU) duration, lower frequency of postoperative extracorporeal membrane oxygenation (ECMO), and trended lower mortality (2.1% vs 5.2%, p=0.051). Operative mortality was lower at higher volume centers (OR_adjusted,_{1-case-increase}: 0.997; CI95%: 0.994-1.0; p=0.025).

Most PEA procedures are performed among a small number of centers, with high-volume hospitals having favorable outcomes. These data suggest a potential role for PEA regionalization.