Assessment of "silent" restenosis and long-term follow-up after successful angioplasty in single vessel coronary artery disease: The value of quantitative exercise electrocardiography and quantitative coronary angiography

Exercise electrocardiographic (ECG) testing during follow-up after coronary angioplasty is widely applied to evaluate the efficacy of angioplasty, even in asymptomatic patients. One hundred forty-one asymptomatic patients without previous myocardial infarction underwent quantitative exercise ECG testing and quantitative coronary angiography 1 to 6 months after successful angioplasty in single vessel coronary artery disease to 1) determine the value of exercise ECG testing to detect "silent" restenosis, and 2) assess the long-term prognostic value of exercise ECG testing and coronary angiography. The prevalence of restenosis (defined as ≥50% luminal narrowing at the dilation site) was 12% in this selected study group. Of 26 patients with an abnormal exercise ECG (ST segment depression ≥0.1 mV), only 4 (15%) showed recurrence of stenosis. Sensitivity and specificity for detection of restenosis were 24% and 82%, respectively. One hundred thirty-four patients (95%) were followed up 1 to 64 months (mean 35) after exercise ECG testing and coronary angiography. Thirty-two patients (24%) experienced a cardiac event: in 25 patients (78%) the initial event was recurrent angina pectoris (New York Heart Association class III or IV) and in 7 patients (22%) it was myocardial infarction, although cardiac death did not occur. The mean interval between exercise ECG testing and the initial cardiac events was 14 months (range 1 to 55), whereas 47% of the initial events took place ≤6 months after exercise ECG testing. An abnormal exercise test result and angiographic restenosis had, respectively, a predictive value of 36% and 41% and a relative risk of 1.7 and 1.9. Gender, age and extent of ST segment depression were not related to the occurrence of cardiac events. Thus, exercise ECG testing is not the technique of choice to detect silent restenosis after coronary angioplasty of single vessel coronary artery disease. An abnormal exercise test result and angiographic evidence of restenosis had only limited value in predicting long-term outcome in this patient group.