Effect of restenosis at one previously dilated coronary site on the probability of restenosis at another previously dilated coronary site

Abstract The purpose of this study was to determine whether in patients with 2 sites dilated by percutaneous transluminal coronary angioplasty (PTCA), the sites undergo restenosis independently. Although restenosis remains a critical limitation after PTCA, there is little information separating site- and patient-dependent determinants of restenosis. In particular, if patients with 2 sites dilated have restenosis at 0 or 2 sites more frequently and at 1 site less frequently than expected by random chance, then patient-related factors may be important in the restenosis process. The source of data was the clinical data base at Emory University. Patients who had previous coronary surgery or PTCA, and those who underwent PTCA in the setting of acute myocardial infarction were excluded. In all, 515 patients with 2 sites dilated undergoing angiographic restudy at 4 months to 1 year after PTCA formed the study population. Site 1 was the first site dilated. At site 1, 224 of 515 sites (45%) were restenotic, and at site 2, 193 (33%) were restenotic. Multiple clinical and angiographic variables were analyzed as possible correlates of restenosis. The most powerful univariate and multivariate correlate of restenosis at either site 1 or 2 was the behavior of the other site. If site 2 was patent, then site 1 was restenotic 28% of the time compared with 69% if site 2 was restenotic. If site 1 was patent, site 2 was restenotic 20% of the time compared with 60% if site 1 was restenotic. This relation was stronger if the 2 sites were in the same coronary artery. Thus, patients cluster with either 0 or 2 sites restenosed. The data support the importance of patient factors that may not have been identified as part of the cause of restenosis after PTCA.