Silent myocardial ischemia: concepts and controversies.

Silent myocardial ischemia is a relatively common, but poorly understood, clinical entity. The most accurate means of detecting silent myocardial ischemia and the precise treatment endpoints remain unclear. However, the amount of ischemic myocardium appears to correlate with the likelihood of future adverse cardiac events. Evidence suggests that patients at highest risk of severe myocardial ischemia, even in the absence of symptoms, derive the greatest benefit from an aggressive diagnostic and therapeutic approach. This paper reviews the diagnosis and treatment of silent myocardial ischemia, and its clinical implication in select patient groups: those without coronary artery disease, those with coronary artery disease, diabetic patients, postrevascularization patients, and women.

Clinical and angiographic profile of patients with markedly elevated coronary calcium scores (>or=1000) detected by electron beam computed tomography.

OBJECTIVE: The objective of this study was to determine the clinical and angiographic profile of patients with extremely high coronary artery calcium scores (CACS; >or=1000) by electron beam computed tomography (EBCT). METHODS: All patients at Rush University Medical Center who had a calcium score >or=1000 and a coronary angiogram performed from 1997 to 2002 were identified using a prospectively collected database. The baseline demographics, symptom status, and degree of coronary stenosis by angiography and subsequent rate of coronary intervention were compared with that of patients with calcium scores <1000. RESULTS: The clinical and angiographic profile of patients with severe coronary calcification, detected by EBCT, revealed that patients with scores >or=1000 had a significantly higher prevalence of coronary stenosis >or=50% compared with patients with scores <1000 (97% vs. 57%, P<.001). The group with CACS >or=1000 was more likely to be male (90% vs. 75%, P=.027) and was older (64+/-8 vs. 59+/-10, P=.001) compared with the group with less severe calcification. Although there was a significantly higher rate of luminal stenosis detected by coronary angiography in the cohort with CACS >or=1000, there was no difference in subsequent percutaneous coronary intervention (PCI) and utilization of intracoronary stents between the two groups. CONCLUSIONS: A markedly elevated coronary calcium score (>or=1000) is correlated with increasing age and is associated with an increased likelihood of coronary stenosis >or=50%. However, the decision to perform coronary angiography in patients with severe coronary calcification should not be based solely on these findings, but should remain primarily dependent on the degree of ischemia detected by clinical and functional assessment.