Post-surgery troponins predict outcomes

In patients who have undergone major vascular surgery, even small elevations in cardiac troponins or creatine kinase-MB fraction (CK-MB) indicate worse long-term outcomes, prospective study findings suggest.

In patients who have undergone major vascular surgery, even small elevations in cardiac troponins or creatine kinase-MB fraction (CK-MB) indicate worse long-term outcomes, prospective study findings suggest. Writing in the Journal of the American College of Cardiology, Giora Landesberg and colleagues say that minor postoperative elevations in these markers, below the conventional cutoffs used to define myocardial infarction (MI), are independent and complementary predictors of long-term mortality. Landesberg’s team, from the Hadassah Medical Center in Jerusalem, Israel, studied 447 consecutive patients who underwent 501 major vascular procedures. In the first 3 days following surgery, all patients were continuously monitored with 12-lead electrocardiogram (ECG) tests, and had blood levels of cardiac troponin-I (cTn-I) and/or troponin-T (cTn-T), and CK-MB measured. Over a mean follow-up period of 32.3 months, there were 82 deaths (18.3%). Using Cox multivariate analysis, the authors identified three postoperative predictors of mortality. These were elevated CK-MB, elevated cTn-T, and prolonged ischemia (>30 minutes). Independent preoperative predictors of long-term mortality were the patient’s age, type of vascular surgery, previous MI, and renal failure. The researchers then evaluated the performance of various cutoffs for the biochemical markers. They found that both CK-MB >10% and cTn-I >1.5 ng/ml and/or cTn-T >0.1 ng/ml independently predicted a 3.75-fold and 2.06-fold increase in long-term mortality. Similarly, both CK-MB >5% and cTn-I >0.6 ng/ml and/or cTn-T >0.03 ng/ml independently predicted a 2.15-fold and 1.89-fold increase in mortality. Furthermore, patients with elevations in both markers had a 4.19-fold increase in mortality. Landesberg says troponin measurements could become an important addition to post-operative monitoring of patients, helping to guide treatment such as the use of beta-blocker therapy. “I believe in routine surveillance of both ECG monitoring for ischemia and daily troponin measurements in high-risk vascular patients. However, the cost-effectiveness of such an approach has not been proven yet. Clinical judgment and sensitivity must be applied by the treating physicians to the most at-risk patients,” he writes. In an accompanying editorial, Allan Jaffe (Mayo Clinic, Rochester, USA) calls the study “a large baby step in the right direction.” He adds: “It documents that patients with troponin increases after vascular surgery are at increased risk for subsequent events. It remains to be seen if those events can be prevented.”(Source: www.incirculation.net)