VERY EARLY PREDICTION OF RESTENOSIS AFTER SUCCESSFUL CORONARY ANGIOPLASTY - ANATOMIC AND FUNCTIONAL ASSESSMENT

To investigate the time course of restenosis, serial treadmill exercise testing was performed in the absence of medical therapy by 31 patients with single vessel coronary disease who underwent successful angioplasty. Exercise tests were performed before angioplasty and at 3 days and 1, 3 and 6 months after angioplasty; if the test was positive, it was repeated after administration of 10 mg of intravenous verapamil. At arteriography 6 months after coronary angioplasty, 17 patients (group 1) showed no restenosis but 14 patients (group 2) did. Before angioplasty all 31 patients had a positive exercise test with ST segment depression ≥1 mm. At 3 days after angioplasty, three patients in group 1 had a positive exercise test compared with 11 patients in group 2 (p = 0.08). At 1,3 and 6 months, 1 patient in group 1 had a positive exercise test compared with 14 patients in group 2 (p < 0.01). The heart rate-blood pressure product (beats/min-mm Hg) calculated at 1 mm ST segment depression, or at peak exercise if the test was negative, was used as an index of the ischemic threshold. In group 1 (no restenosis) the ischemic threshold increased progressively from 14,840 ± 1,075 (mean value ± SEM) before angioplasty to 21,210 ± 1,049 at 3 days and to 25,140 ± 1,177 (p < 0.001) at 6 months. In group 2 (restenosis) the ischemic threshold increased from 16,270 ± 828 before angioplasty to 20,400 ± 984 (p < 0.0004) at 3 days but decreased to 16,090 ± 1,298 (p < 0.006) at 6 months. The difference in ischemic threshold between the two groups was significant (p < 0.05) from 1 month onward. In group 2 patients the increase in ischemic threshold after verapamil was greater at 3 and 6 months after than before angioplasty (p < 0.01). The early high incidence of a positive exercise test indicates that the process of restenosis begins at least within 1 month of angioplasty and perhaps as early as 3 days. Furthermore, the dynamic component of the stenosis after angioplasty is greater than that of the original stenosis, as suggested by the response to verapamil. © 1990, American College of Cardiology Foundation. All rights reserved.