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Multivariate clinical models and quantitative dipyridamole-thallium imaging to predict cardiac morbidity and death
J Lette1, D Waters, J Lassonde
1Department of Medicine, Maisonneuve Hospital Centre, Montreal, Quebec, Canada.
Insights
Dipyridamole-thallium imaging effectively predicts cardiac events after vascular surgery. Quantitative analysis stratifies patients with reversible defects into intermediate and high-risk groups, guiding treatment decisions for coronary artery disease.
Area of Science:
- Cardiology
- Vascular Surgery
- Nuclear Cardiology
Background:
- Patients with peripheral vascular disease (PVD) often have concurrent coronary artery disease (CAD).
- This high prevalence increases the risk of cardiac complications and death following vascular reconstruction surgery.
Purpose of the Study:
- To evaluate the predictive value of clinical parameters, scoring systems, and quantitative dipyridamole-thallium imaging for postoperative cardiac events.
- To identify high-risk patients undergoing vascular surgery who may benefit from further cardiac evaluation.
Main Methods:
- A prospective study involving 125 patients undergoing vascular surgery.
- Assessment of 18 clinical parameters and 7 clinical scoring systems.
- Quantitative dipyridamole-thallium imaging to assess myocardial perfusion.
Main Results:
- Clinical parameters and scoring systems showed limited predictive value for postoperative cardiac events.
- Dipyridamole-thallium imaging identified patients at risk: 21% with reversible defects experienced complications.
- Quantitative analysis stratified reversible defects into intermediate (5% event rate) and high-risk (85% event rate) subgroups.
Conclusions:
- Quantitative dipyridamole-thallium imaging is superior to clinical assessment for predicting cardiac events post-vascular surgery.
- High-risk patients identified by imaging require further cardiac evaluation, such as coronary angiography.
- This imaging modality enables risk stratification, optimizing perioperative management for patients with PVD and suspected CAD.
Abstract:
Patients with peripheral vascular disease have a high prevalence of coronary artery disease and are at increased risk for cardiac morbidity and death after vascular reconstruction. The present study was undertaken to assess the value of 18 clinical parameters, of 7 clinical scoring systems, and of quantitative dipyridamole-thallium imaging for predicting the occurrence of postoperative myocardial infarction or cardiac death. Vascular surgery was performed in 125 patients. Thirteen postoperative cardiac events occurred, including 10 cardiac deaths and 3 nonfatal infarctions. Clinical parameters were not useful in predicting postoperative outcome. All 63 patients with normal scan results or fixed perfusion defects underwent surgery uneventfully, whereas 21% (13/62) of patients with reversible defects had a postoperative cardiac complication. By use of quantitative scintigraphic indexes we found that patients with reversible defects could be stratified into intermediate and high-risk subgroups with postoperative event rates of 5% (2/47) and 85% (11/13), respectively, despite intensive postoperative monitoring and antianginal medication. Thus in patients unable to complete a standard exercise stress test, postoperative outcome cannot be predicted clinically, whereas dipyridamole-thallium imaging successfully identified all patients who had a postoperative cardiac event. By use of quantification we found that patients with reversible defects can be stratified into an intermediate risk subgroup that can undergo surgery with minimal complication rate and a high-risk subgroup that requires coronary angiography.