Quantification of Ischemia As a Prognostic Mandate for Coronary Revascularization in Asymptomatic Patients: How Much
Asad Shabbir1,2, Lampson Fan1, Gregory Fraser1
1From the John Radcliffe Hospital, Oxford University Hospital NHS Foundation Trust, Oxford, United Kingdom.
Insights
Asymptomatic patients with coronary artery disease and significant ischemia benefit from revascularization. Prompt intervention improves survival and preserves heart function, regardless of symptom presentation.
Area of Science:
- Cardiology
- Ischemic Heart Disease
- Preventive Cardiology
Background:
- Coronary artery disease (CAD) is a leading cause of mortality.
- Asymptomatic myocardial ischemia in known CAD patients poses a significant risk.
- Prognostic implications of silent ischemia require further investigation.
Purpose of the Study:
- To evaluate the prognostic benefit of revascularization in asymptomatic patients with known CAD and myocardial ischemia.
- To determine if inducible ischemia magnitude predicts cardiovascular outcomes.
- To assess the impact of revascularization on left ventricular function.
Main Methods:
- Systematic literature review of Medline and PubMed databases.
- Inclusion of 7 clinical trials and prominent review articles.
- Analysis of data correlating inducible ischemia with cardiovascular events.
Main Results:
- A strong correlation exists between the magnitude of inducible ischemia and adverse cardiovascular outcomes (death, myocardial infarction, hospitalization).
- Patients with ≥10% inducible ischemia demonstrated a >50% reduction in mortality following revascularization (P < 0.00001).
- Revascularization preserved left ventricular ejection fraction (53.9%) compared to medical therapy alone (48.8%) (P < 0.001).
Conclusions:
- Silent ischemia is a critical prognostic marker in patients with known CAD.
- Revascularization is recommended for asymptomatic patients with known CAD and ≥10% inducible ischemia.
- Recommended thresholds for revascularization include ≥3 abnormal wall motion segments or ≥2 perfusion deficits on imaging.
Abstract:
The aim of this study was to investigate whether asymptomatic patients with known coronary artery disease and demonstrable myocardial ischemia warrant revascularization on prognostic grounds. A Medline and PubMed search was performed, including 7 trials with data discussed and concise reviews of prominent articles in the field. The magnitude of inducible ischemia in those with known coronary disease correlates closely with poor cardiovascular outcomes in terms of death, myocardial infarction, hospitalization, and revascularization. Patients with ≥10% inducible ischemia experience a survival advantage when revascularized with a reduction in mortality of greater than 50% regardless of symptoms (P < 0.00001). Evidence also suggests that left ventricular function remains preserved in those who are revascularized when compared with medical therapy alone; left ventricular ejection fraction 53.9% versus 48.8% (P < 0.001). Silent ischemia is a useful prognostic marker in those with known coronary disease. It is recommended that asymptomatic patients with known coronary disease be revascularized on prognostic grounds if ≥10% ischemia can be demonstrated on nuclear or myocardial perfusion scan, ≥3 segments of regional wall motion abnormality on stress echocardiography/cardiac magnetic resonance imaging, or ≥2 segments with perfusion deficits on stress perfusion cardiac magnetic resonance imaging.
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