Cardiac troponin I release after hip surgery correlates with poor long-term cardiac outcome

Background and objective: The aim of this study was to assess the incidence of perioperative myocardial damage detected by serial measurements of troponin 1 after hip surgery and its association with late cardiovascular outcome. Methods: Troponin I was measured during the first three postoperative days in 88 consecutive patients undergoing hip surgery. Values above the 99th percentile (0.08 ng mL(-1)) were considered positive. Major cardiac events (cardiac death, myocardial infarction and cardiac failure) were recorded during hospital stay and 1 yr after surgery. Results: Eleven patients (12.5%) exhibited elevated troponin I levels during hospital stay. Nine of them remained asymptomatic. During follow-up, 45 916 of them (5/11) suffered from a major cardiac event vs. 4% (3/76) for patients with normal postoperative troponin I levels (P = 0.0006). All-cause mortality rate was 36% (4/11) at 1 yr vs. 7% (5/71, P = 0.0131). Using multivariate Cox regression analysis adjusted for baseline data, independent factors associated with the occurrence of a cardiac event were troponin I elevation (OR = 17.4 - CI 95% 3.7-82) and age (OR = 1.1 yr(-1) -CI 95% 1.01-1.21). Independent factors for all-cause mortality were troponin I elevation (OR=41.4 - CI 95% 5.4-320.4), and age (OR=1.3 yr(-1) - CI 95% 1.1-1.4). Conclusion: Troponin I release is common after hip surgery and is associated with a 10-fold increased incidence of long-term major cardiac events as compared to patients with normal troponin I levels (45% vs. 4%).