Postoperative Cardiac Damage After Standardized Carotid Endarterectomy Procedures in Low- and High-Risk Patients

Background: We conducted a comparison of postoperative cardiac damage, defined as cardiac troponin I (cTn-I) elevation, after carotid endarterectomy in low- and high-risk patients. Methods: The Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) criteria for stratifying patients considered for carotid endarterectomy into low and high surgical risk groups were used prospectively. All patients had preoperative full cardiologic evaluations and cTn-I value assessments that were repeated on postoperative days 1, 3, and 7. Postoperative cTn-I values ranging from 0.05 to 0.5 ng/mL were classified as myocardial ischemia; values >0.5 ng/mL were classified as myocardial infarction. Results: Mortality was 1.2%, the stroke rate was null, and symptomatic myocardial infarction was null. Among the 56 high-risk patients, 8 had cTn-I values >0.5 ng/mL. Among the 106 low-risk patients, 10 patients had cTn-I value >0.5 ng/mL and 4 patients had cTn-I values that were >0.05 ng/mL and <= 0.5 ng/mL. All patients with increased cTn-I levels were asymptomatic. Concerning all patients, the mean preoperative cTn-I value was 0.007 ng/mL, which increased to 0.438 ng/mL on postoperative day 1 (P = 0.017), 0.168 ng/mL on postoperative day 3 (P = 0.06), and 0.019 ng/mL on postoperative day 7 (P = 0.02). In the high-risk group, the mean preoperative cTn-I value was 0.008 ng/mL, which increased to 0.829 ng/mL on postoperative day 1, 0.270 ng/mL on postoperative day 3, and 0.030 ng/mL on postoperative day 7. In the low-risk group, the mean preoperative cTn-I value was 0.007 ng/mL, which increased to 0.198 ng/mL on postoperative day 1, 0.119 ng/mL on postoperative day 3, and 0.013 ng/mL on postoperative day 7. Patients without cardiac damage showed analogous tendencies in their troponin values. Comparison of troponin values between high- and low-risk patients on each day showed no statistical difference. Electrocardiogram alterations were seen in 20 of the 22 patients with asymptomatic troponin elevation but in none without troponin elevation. Conclusions: Carotid endarterectomy is followed by an increase in cTn-I value >0.5 ng/mL in 14% of all cases, although symptomatic cardiac ischemia is very low. However, high-risk patients as defined by the SAPPHIRE criteria do not show an increased risk of cardiac damage compared to low-risk patients. Larger studies using cTn-I as a marker of postoperative cardiac damage, after carotid endarterectomy or stenting, are needed.