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The use of preoperative exercise testing to predict cardiac complications after arterial reconstruction
N McPhail1, J E Calvin, A Shariatmadar
1Division of Vascular Surgery, University of Ottawa, Ontario, Canada.
Insights
Preoperative exercise testing accurately predicts cardiac complications in patients undergoing arterial reconstructive surgery. Achieving over 85% predicted maximum heart rate indicates a low-risk group for cardiac events.
Area of Science:
- Cardiology
- Vascular Surgery
- Exercise Physiology
Background:
- Cardiac complications pose a significant risk for patients undergoing major arterial reconstructive surgery.
- Accurate preoperative risk stratification is crucial for optimizing patient outcomes.
Purpose of the Study:
- To evaluate the utility of exercise testing in predicting cardiac complications following arterial reconstructive procedures.
- To identify specific exercise parameters associated with reduced postoperative cardiac risk.
Main Methods:
- 100 patients undergoing arterial reconstructive surgery (abdominal aortic aneurysm repair, aortoiliac occlusive disease reconstruction, infrainguinal revascularization) underwent preoperative treadmill or arm ergometry testing.
- Cardiac complications (myocardial infarction, congestive heart failure, arrhythmias, death) were monitored postoperatively.
- Contingency table analysis and logistic regression were used to identify predictors of cardiac complications.
Main Results:
- Patients achieving less than 85% of predicted maximum heart rate (PMHR) had a 24% complication rate versus 6% for those achieving >85% PMHR (p=0.0396).
- A positive stress test combined with <85% PMHR yielded a 33% complication rate, while a positive stress test with >85% PMHR had no complications (p=0.048).
- High maximum heart rate (p=0.04) and high maximal oxygen uptake (p=0.03) during exercise testing were significant predictors of low postoperative cardiac complications.
Conclusions:
- Preoperative exercise testing is a valuable tool for predicting cardiac complications after arterial reconstructive surgery.
- Patients achieving >85% PMHR and high maximal oxygen uptake represent a low-risk group for postoperative cardiac events.
- These findings support the integration of exercise testing into the preoperative assessment of vascular surgery patients.
Abstract:
To assess the value of exercise testing in the prediction of cardiac risk, 100 patients requiring arterial reconstructive surgery had either treadmill testing or arm ergometry before operation. Thirty-four patients then had abdominal aortic aneurysm repair, 48 had reconstructions for aortoiliac occlusive disease, and 18 had infrainguinal revascularization procedures. Cardiac complications included myocardial infarction in 10%, acute congestive failure in 5%, malignant ventricular arrhythmias in 7%, and cardiac death in 7%. Contingency table analysis showed that patients who achieved less than 85% of their predicted maximum heart rate (PMHR) during exercise testing had a complication rate of 24%, whereas patients who achieved more than 85% of PMHR had a 6% complication rate (p = 0.0396). The degree of ST segment depression during exercise testing was not a significant predictor of cardiac complications. However, patients who had a positive stress test (ST depression more than 1 mm) and achieved less than 85% of their PMHR had a complication rate of 33%, whereas patients with a positive stress test who achieved more than 85% of their PMHR had no complications (p = 0.048). Statistical analysis with a logistic regression model showed two factors to be significant. Patients who achieved a high maximum heart rate during exercise testing had a low probability of developing postoperative cardiac complications (p = 0.04), as did patients who achieved high cardiac work load maximal oxygen uptake (p = 0.03). We conclude that preoperative exercise testing is useful to predict cardiac complications after arterial reconstruction. Patients who are able to achieve more than 85% of their PMHR and a high maximal oxygen uptake represent a low-risk group.