Abstract 16667: Computed Tomography-Based Pulmonary Vascular Tortuosity as a Marker in Resting and Exercise Pulmonary Arterial Hypertension

Abstract

Introduction: Increased vascular tortuosity has been proposed as a marker of pulmonary arterial hypertension (PAH). In this analysis, we compared arterial and venous vascular tortuosity between controls and subjects with resting PAH. Furthermore, we examined if abnormalities could be detected in exercise PAH (EPAH), thought to be an early form of PAH. Methods: From an institutional registry, 388 patients with both right heart catheterization and computed tomography angiography (CTA) data were selected. Within this cohort, three distinct groups were identified: 1) controls, who had no cardiopulmonary disease and normal resting and exercise hemodynamics; 2) EPAH, with normal resting hemodynamics but age-adjusted pre-capillary pulmonary hypertension on exertion, and 3) PAH, defined as resting mPAP >20mmHg, pulmonary vascular resistance >3 Wood Units, and pulmonary capillary wedge pressure <15mmHg. Tortuosity was defined as the actual path length of a vessel divided by the linear distance between the two farthest endpoints of the vessel segment on CTA. AV>10% was defined as the number of arterial segments with tortuosity >10% divided by the same venous measure. Analysis was performed with Wilcoxon rank sum tests in R 3.5. Results: There were 99 patients in the final cohort, including 47 (47.4%) with PAH, 12 (12.1%) with EPAH, and 40 (40.4%) without disease. Compared to controls, median arterial tortuosity was increased in PAH (3.3 ± 0.1% vs. 3.4 ± 0.1%, p=0.0009; Figure 1) but not in EPAH (3.3 ± 0.1%, p=0.82). Median venous tortuosity did not differ between groups. AV>10% was increased in EPAH (vs. controls, 1.86 ± 0.38 vs. 1.56 ± 0.44, p=0.03) and resting PAH (2.0 ± 1.2 p=2e-6). Conclusions: Increased arterial tortuosity on CTA is a biomarker of resting PAH. When corrected for venous tortuosity, arterial tortuosity also appears to be abnormal in EPAH. Figure 1 . Arterial vessels in PAH, EPAH, and control subjects. Red segments have tortuosity > 10%.