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Vascular wall remodeling in primary pulmonary hypertension (PPH) contributes to the development and maintaining of elevated pulmonary pressures. Optical coherence tomography (OCT) is a diagnostic tool that is able to image small arterial vessels. Aim of this study was to evaluate the vascular remodeling of small pulmonary arteries (from 1 to 4 mm diameter) in a group of patients with PPH and to relate morphologic changes to pulmonary hemodynamics.
8 patients (group 1)(7 f, 1 m, mean age 52.7±9.2 years) with PPH and 6 patients (group 2) with normal pulmonary hemodynamics (3 m, 3 f, mean age 56.7±11.7 years), underwent to OCT examination during right cardiac catheterization. The image wire was pulled from distal to proximal portions of right and left distal 1.0 to 4 mm pulmonary vessels using a motorized pull-back system at 1.0 mm/sec. The following parameters were measured: endoluminal diameter (ELD), endoluminal area (ELA), wall thickness (WT), pulmonary systolic, mean and diastolic pressure (PSP, PMP, PDP), pulmonary wedge pressure (WP), cardiac output (CO), cardiac index (CI), pulmonary vascular resistances (PVR).
PSP, PDP, PMP and PVR were significantly different between group 1 and group 2 (79.3±18.6 vs 28.4±4.7 mmHg; 35.8±17.9 vs 8.3±4.6 mmHg; 52.4±18.4 mmHg; 924±138 vs 82±15 dyne/sec/cm-5, respectively). No Significant difference was encountered between group 1 and 2 for mean ELD (2.8±0.9 vs 2.5±1.0 mm) and ELA 8.9±4.7 vs 9.2±3.8 mm) respectively. Mean arterial WT was 0.52±0.07 mm in group 1 vs 0.09±0.02 mm in group 2 (p<0.001) while ELD/WT ratio was 5.7±0.6 vs 2.6±0.5 (p<0.01). were shown. Furthermore a direct linear significant relation was shown between WT and MPP (r 0.94, p<0.001). Significant relation were also shown between WT and SPP (r 0.75, p<0.01), DPP (r 0.69 p<0.01) and between ELD/WT ratio and MPP (r 0.87 p<0.001), SPP (r 0.77, p<0.01), DPP (r 0.66, p<0.01). From a purely morphologic point of view, in all patients with PPH perivascular adventitial gaps not present in group 2 (neovascularization from vasa vasorum?) were shown.
OCT assessment of small pulmonary arteries gives useful morphologic and information on the remodeling process of pulmonary vasculature and on its relation with pulmonary hemodynamics in patients with PPH.
- 2013 American College of Cardiology Foundation