Coronary stenosis vasomotion during dynamic exercise before and after PTCA

Coronary vasomotion was evaluated in eight patients (age 50 +/- 8 years) with coronary disease before and 3.3 +/- 1.9 months after successful percutaneous transluminal coronary angioplasty (PTCA). Luminal area of a normal and a stenotic coronary artery was determined before and after PTCA using biplane quantitative coronary arteriography. Patients were studied at rest, during supine bicycle exercise and 5 min after 1.6 mg sublingual nitroglycerin. Workloads before and after PTCA were identical. Percentage diameter stenosis decreased from 78% to 24% (P less than 0.001) after PTCA. Mean pulmonary artery pressure increased during exercise from 21 to 40 mmHg (P less than 0.001) before and from 19 to 34 mmHg (P less than 0.001) after PTCA. Peak exercise pulmonary artery mean pressure was significantly (P less than 0.05) lower after PTCA. Normal coronary arteries showed a minimal increase in mean luminal area before (+2%; NS) as well as after (+6%; NS) PTCA. Nitroglycerin produced dilation of the normal vessel segment to a similar extent pre- (+27%; P less than 0.001) and post- (+31%; P less than 0.001) PTCA. In contrast, stenotic vessel segments showed coronary vasoconstriction during exercise before PTCA (-28%; P less than 0.01); after PTCA, exercise-induced vasoconstriction of the diseased segment was minimal (-4%; NS). Nitroglycerin was associated with vasodilation of the stenotic vessel segment before (+17%; NS) as well as after (+26%; P less than 0.005) PTCA. Thus, exercise-induced coronary vasoconstriction of stenotic coronary arteries is observed before as well as after PTCA, but vasoconstriction after PTCA is significantly less than before PTCA.(ABSTRACT TRUNCATED AT 250 WORDS)