Optical coherence tomography for hypertensive pulmonary vasculature

BackgroundOptical coherence tomography (OCT) is an intravascular imaging modality capable of providing in situ images of tissues at near histologic resolution. In this study we examine the utility of OCT in identifying vascular changes related to pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH).Methods and resultsOCT of four different distal pulmonary arteries was performed during right heart catheterization in 87 patients, 64 patients with PAH and 23 patients with CTEPH. The mean luminal diameter measured by OCT for all patients was 2.26 mm. Intimal thickening was significantly increased in all PAH patients (0.26 ± 0.05 mm in idiopathic PAH, 0.24 ± 0.03 mm in connective tissue disease related PAH, 0.26 ± 0.06 mm in congenital heart disease related PAH and 0.22 ± 0.04 mm in CTEPH, respectively) compared with controls (0.13 ± 0.03 mm) (all p < 0.05). An intimal thickness of ≥ 0.176 mm had a 91% positive predictive value for pulmonary hypertension. The anatomic abnormalities revealed by OCT tended to be severe in the idiopathic PAH group and mild in the CTEPH group. Signs of intravascular webs were found in 60.9% of CTEPH patients, but no other patients. Intimal thickness was moderately correlated with pulmonary arterial pressure and pulmonary vascular resistance (r = 0.423 and 0.439, respectively, p < 0.001).ConclusionsOCT provides important information for assessment of pulmonary arterial remodeling in patients with PAH and improves diagnostic capability of angiographically undetected distal-thrombotic lesions in patients with CTEPH.