Pulmonary arterial histology and morphometry in systemic sclerosis: a case-control autopsy study.

Morphometric measurements were performed on pulmonary arteries in 58 patients with systemic sclerosis (20 limited cutaneous and 38 diffuse cutaneous involvement [21 with and 17 without renal crisis]) and age, race, and sex matched autopsy controls. Matched pairs analysis was employed. For arteries of all sizes, the area of the intima and percent luminal occlusion were greater in the limited and diffuse (no renal crisis) groups than in controls, and these differences were statistically significant for large and medium sized vessels. The greatest luminal occlusion was found in limited cutaneous patients, and especially those with clinical evidence of pulmonary arterial hypertension, providing a rationale for the poor response to vasodilator therapy in these patients.