Preventive mechanisms and effects of pemirolast potassium on restenosis after percutaneous transluminal coronary angioplasty: serial coronary angiography and intravascular ultrasound studies

Pemirolast potassium, an antiallergic agent, has preventive effects against restenosis after percutaneous transluminal coronary angioplasty (PTCA). This study investigated the mechanism of the preventive effects of pemirolast on restenosis using serial intravascular ultrasound (IVUS). Initial elective PTCA was performed in consecutive 106 patients from March 1996 through August 1997. Patients with type C lesions or graft stenosis were excluded from the study. A total of 97 patients with 110 lesions, 48 patients (56 lesions) in the pemirolast treated group and 49 patients (54 lesions) in the control group were analyzed. Restenosis was defined as a diameter stenosis of > or = 50% at follow-up study. Patients in the pemirolast group received 20 mg/day from the morning after angioplasty until the time of follow-up (mean 6 months). The lumen cross-sectional area, vessel area, plaque area, and % plaque area were measured by quantitative coronary ultrasound and compared after PTCA and at follow-up between the patients without restenosis in the pemirolast (28 lesions) and control (27 lesions) groups. There was no significant change in baseline characteristics between the 2 groups. Restenosis rate per lesion was significantly lower in the pemirolast group than in the control group (23.2% vs 44.4%, p < 0.05, respectively). After angioplasty and at follow-up study, there was no difference in lumen and vessel cross-sectional areas between the 2 groups. However, plaque and % plaque area in the pemirolast group were smaller than in the control group at follow-up study (8.9 +/- 2.3 vs 11.8 +/- 3.5 mm2, p < 0.005, 56.0 +/- 9.0% vs 64.0 +/- 10.4%, p < 0.005, respectively). These results suggest that suppression of neointimal hyperplasia is the preventive mechanism of pemirolast against restenosis after angioplasty. Pemirolast may be more effective against restenosis after coronary stenting.