Silent Myocardial Ischemia in Patients after Permanent Coronary Intervention

Abstract

Frequency and timing of appearance of myocardial ischemia, including silent ischemia, were analyzed in published scientific sources. Silent myocardial ischemia is risk factor for stent restenosis after percutaneous coronary interventions. Patients with silent ischemia lack clinical symptoms while perfusion, metabolic and electrical activity of their myocardium may be compromised. These patients do not have warning clinical symptoms during physical exercise and do not stop inappropriate activity. Silent myocardial ischemia itself can indicate severity of atherosclerosis in coronary arteries. High probability of stent restenosis can be assessed by exercise tests prior to coronary angiography. These tests also allow to reveal clinically silent myocardial ischemia. Quarter of patients after coronary intervention develop silent myocardial ischemia. Silent myocardial infarction comprises 22-78 % of all infarctions after coronary interventions. Exercise tests based on single-photon emitting computed tomography can be used in diagnosing stent restenosis, silent ischemia and assessment of cardiovascular risk in patients after coronary interventions. Its results can be used as indications for repeated coronary interventions and for prognosis after revascularization. Exercise tests are recommended in two years after revascularization in absence of ischemic symptoms. Early tests are recommended in cases of high cardiovascular risk, suboptimal revascularization, stenting of arteries with small diameter or at bifurcation. Diagnosis of silent myocardial ischemia by single-photon emitting computed tomography in patients after coronary revascularization is significant for clinical practice.