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Prognostic significance of silent ischemia
S B Pancholy1, B Schalet, V Kuhlmeier
1Philadelphia Heart Institute, Presbyterian Medical Center, PA 19104, USA.
Insights
Patients with coronary artery disease (CAD) and either symptomatic or silent ischemia have similar prognoses. The extent of myocardial perfusion abnormality, not angina presence, predicts cardiac events in medically treated CAD patients.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Cardiovascular Imaging
Background:
- Coronary artery disease (CAD) affects millions globally.
- Distinguishing between symptomatic and silent ischemia is crucial for prognosis.
- Exercise thallium imaging is a key diagnostic tool for CAD.
Purpose of the Study:
- To compare the prognostic predictors in patients with symptomatic versus silent ischemia.
- To identify key factors influencing cardiac events in medically treated CAD patients.
Main Methods:
- Study included 521 patients with angiographic CAD.
- Patients underwent exercise single-photon emission computed tomographic thallium imaging.
- Groups were defined by symptomatic ischemia (angina during exercise) versus silent ischemia (no angina).
Main Results:
- No significant difference in event-free survival between symptomatic and silent ischemia groups.
- 2-year event-free survival rates were 95% (symptomatic) and 94% (silent).
- Extent of perfusion abnormality and diabetes mellitus were the strongest predictors of cardiac events.
Conclusions:
- Prognosis for medically treated CAD patients is similar regardless of symptomatic or silent ischemia.
- Myocardial risk, indicated by perfusion abnormalities, is a more significant prognostic factor than angina presence.
- Diabetes mellitus is a critical comorbidity impacting CAD outcomes.
Abstract:
This study examined the prognostic predictors in 521 patients with angiographic evidence of coronary artery disease (CAD). All patients underwent exercise single-photon emission computed tomographic thallium imaging. The patients were divided into those with symptomatic ischemia defined as reversible thallium defects, S-T segment depression (or both) and angina during exercise (n = 210, group 1), and silent ischemia defined as thallium defects or ST segment depression (or both) but no angina during exercise (n = 311, group 2). During a mean follow-up of 24 +/- 21 months, there were 30 cardiac events (death or nonfatal myocardial infarction). The extent of CAD (2.0 +/- 0.8 diseased vessels in group 1 and 2.1 +/- 0.8 diseased vessels in group 2), the left ventricular ejection fraction, the extent of perfusion abnormality (21% +/- 11% in group 1 and 24% +/- 12% in group 2), and the peak heart rate and double product were similar in the two groups. Survival analysis showed no significant difference in the event-free survival in patients with symptomatic or silent ischemia. The 2-year event-free survival rate was 95% in group 1 and 94% in group 2 (difference not significant). The extent of perfusion abnormality and history of diabetes mellitus were the most important predictors of events. Thus the prognosis of medically treated patients with CAD is comparable in those patients with silent or symptomatic ischemia and is dependent on the extent of myocardium at risk rather than presence or absence of angina pectoris during exercise.