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Dipyridamole-thallium scan for screening of coronary artery disease prior to vascular surgery
J P Fletcher1, V F Antico, S Gruenewald
1Department of Surgery Westmead Hospital, Sydney, Australia.
Insights
Dipyridamole-thallium scanning effectively screens for coronary artery disease in vascular surgery patients. Positive scans indicate a higher risk of heart attack after surgery, necessitating further investigation and potential bypass surgery.
Area of Science:
- Cardiology
- Vascular Surgery
- Diagnostic Imaging
Background:
- Patients with extracranial cerebrovascular disease and peripheral vascular disease face elevated risks of ischemic heart disease and mortality post-vascular reconstruction.
- Preoperative cardiac assessment is crucial for optimizing outcomes in these high-risk surgical candidates.
Purpose of the Study:
- To evaluate the efficacy of dipyridamole-thallium scanning as a preoperative screening tool for coronary artery disease (CAD) in patients undergoing major vascular surgery.
- To determine the correlation between positive dipyridamole-thallium scan results and postoperative myocardial infarction (MI) and mortality.
- To assess the impact of coronary artery bypass grafting (CABG) on reducing perioperative cardiac events.
Main Methods:
- A prospective study involving 67 patients undergoing carotid or aortic surgery over two years.
- Preoperative dipyridamole-thallium (Persantine-thallium) scans were performed to assess for inducible ischemia.
- Outcomes, including postoperative MI and mortality, were compared between patients with positive and negative scans, and in those who underwent CABG.
Main Results:
- Three of the first 17 patients with positive scans experienced postoperative MI (one fatal), versus none in 14 with negative scans (p=0.02).
- In the subsequent 50 patients, seven had positive scans.
- Patients with left main trunk or triple-vessel disease who underwent CABG prior to or combined with vascular reconstruction had significantly reduced morbidity (no deaths or MIs, p=0.01).
Conclusions:
- Dipyridamole-thallium scanning is an effective method for screening patients with peripheral or cerebrovascular disease for significant coronary artery disease before vascular reconstruction.
- Positive scans identify patients at increased risk for perioperative myocardial infarction.
- Coronary arteriography followed by revascularization (CABG) is recommended for patients with positive scans, especially those with left main or triple-vessel disease, to improve surgical outcomes.
Abstract:
Patients with extracranial cerebrovascular disease and peripheral vascular disease are at increased risk of ischaemic heart disease with resulting increased risk of early and late mortality following vascular reconstruction. Over a two year period, 67 patients undergoing carotid or aortic surgery were investigated preoperatively with dipyridamole-thallium scan. There were three positive scans in the first 17 patients; two of these patients suffered a postoperative myocardial infarction (one fatal), compared to none of 14 who had a negative scan (p = 0.02). There were seven positive scans in the next 50 patients. Patients with left main trunk or triple vessel disease were recommended to have coronary artery bypass prior to or combined with the vascular reconstruction. There were no deaths or postoperative myocardial infarction in this group, this improvement in morbidity being statistically significant (p = 0.01). Dipyridamole-thallium scanning is an effective screening procedure for coronary artery disease. Patients with a positive scan are at increased risk of postoperative myocardial infarction following vascular reconstruction. Further investigation with coronary arteriography prior to vascular reconstruction is recommended in patients with positive scans. Coronary artery bypass should be performed prior to or combined with the vascular reconstruction in patients with left main trunk or triple vessel disease.