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Risk stratification of single or double vessel coronary artery disease and impaired left ventricular function using
T D Miller1, C P Taliercio, A R Zinsmeister
1Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic and Foundation, Rochester, Minnesota 55905.
Insights
Exercise radionuclide angiography helps identify patients with 1- or 2-vessel coronary artery disease and impaired left ventricular function who are at high risk for future cardiac events. Severe ischemia on this test predicts worse outcomes.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Diagnostic Imaging
Background:
- Patients with coronary artery disease (CAD) and impaired left ventricular (LV) function often have complex prognoses.
- Risk stratification is crucial for guiding treatment decisions in these patients.
Purpose of the Study:
- To evaluate the utility of exercise radionuclide angiography in risk stratifying patients with 1- or 2-vessel CAD and reduced LV ejection fraction (<50%).
Main Methods:
- Sixty-five patients with 1- or 2-vessel CAD and LV ejection fraction <50% underwent exercise radionuclide angiography.
- Patients were followed for a median of 24 months for cardiac events.
- Severe ischemia was defined by specific criteria including decreased ejection fraction, ST-segment depression, and low exercise workload.
Main Results:
- 17% of patients exhibited severely ischemic exercise radionuclide angiograms.
- Patients with severe ischemia had a significantly higher rate of cardiac events (36% vs. 13%) and lower event-free survival at 18 months (73% vs. 92%).
- Severe ischemia on exercise radionuclide angiography was the only significant predictor of future cardiac events.
Conclusions:
- Exercise radionuclide angiography is a valuable tool for identifying high-risk patients among those with 1- or 2-vessel CAD and impaired LV function.
- This imaging modality aids in predicting future cardiac events in this specific patient population.
Abstract:
Patients with 3-vessel coronary artery disease (CAD) and normal left ventricular (LV) function have a worse prognosis if they manifest ischemia during exercise testing. The present study determines if exercise radionuclide angiography can aid in the risk stratification of patients with 1- or 2-vessel CAD and impaired LV function (ejection fraction less than 50%). Sixty-five consecutive patients with these findings were followed for a median duration of 24 months (range 12 to 49). Eleven of the 65 patients (17%) had severely ischemic exercise radionuclide angiograms, defined as: a decrease in ejection fraction with exercise; greater than or equal to 1.0 mm of ST-segment depression; and peak exercise workload less than or equal to 600 kg-m/min. During follow-up 11 patients had initial significant cardiac events: 4 cardiac deaths, 1 cardiac arrest, 4 myocardial infarctions and 2 bypass or angioplasty procedures for unstable angina greater than or equal to 3 months after the exercise study. Four of 11 patients (36%) with severely ischemic exercise radionuclide angiograms had events, compared to 7 of 54 patients (13%) without ischemic radionuclide angiograms. Event-free survival at 18 months was 73% for patients with severe exercise ischemia versus 92% for those without ischemia (p less than 0.05). Univariate analysis showed that severe ischemia on radionuclide angiography was the only variable of several tested that significantly predicted future cardiac events (chi-square = 8.16, p less than 0.005). Among patients with 1- or 2-vessel CAD and impaired resting LV function, severe ischemia on exercise radionuclide angiography identifies a subgroup at high risk for future cardiac events.