Aims: We sought to find out what factors are important for long-term prognosis, the small vessel itself or abnormal glucose tolerance, in patients treated with coronary angioplasty.
Background: Patients with coronary artery disease with diabetes mellitus often show diffuse and small coronary artery narrowing. Impaired glucose tolerance has also been reported to be a risk factor for cardiovascular disease.
Methods: Among 584 patients who underwent first elective balloon coronary angioplasty, diabetes mellitus and impaired glucose tolerance were present in 197 patients. Large and small vessels were defined by reference vessel diameter before coronary angioplasty as either larger or smaller than 2.5 mm. Patients were categorized into the following four groups: 175 patients with normal glucose tolerance and reference diameter <2.5 mm (group SN), 212 patients with normal glucose tolerance and reference diameter greater than or = 2.5 mm (group LN), 101 patients with abnormal glucose tolerance and reference diameter <2.5 mm (group SD), and 96 patients with abnormal glucose tolerance and reference diameter greater than or = 2.5 mm (Group LD). The cardiac events were compared for a period of 8 years after coronary angioplasty among the four groups.
Results: There was no difference in the percentage diameter stenosis immediately after coronary angioplasty among the four groups. However, group SD showed unfavourable prognosis despite similar minimal lumen diameter after coronary angioplasty compared with group SN. Event-free survival curve of group LD showed a sudden drop approximately 5 years after the coronary angioplasty. In multivariate analysis, the cardiac events were associated with the presence or absence of abnormal glucose tolerance. Furthermore, patients with bad glycaemic control (HbA1c>6.0%) at index coronary angioplasty showed worse event free survival than those with good glycaemic control.
Conclusions: An important determinant for long-term prognosis after coronary angioplasty is a presence of abnormal glucose tolerance per se and not small vessel diameter.