Elevated Troponin Levels May Be a Marker for Increased Mortality in ACS

October 10, 2007 (Seattle) — Patients with acute coronary syndrome presenting to the emergency department with transient elevation in the ST segment of their electrocardiogram (ECG) who also have elevated troponin levels may be at increased risk for death. The finding suggests that such patients should be treated more aggressively.
Researchers presented the study here at the American College of Emergency Physicians (ACEP) 38th Annual Scientific Assembly.
ECG changes can suggest either acute injury to the heart (elevated ST segment) or ischemia (normal ST segment). However, some patients present with transient ST-segment elevation (tSTE), and there is no consensus for how aggressively these patients should be treated. Using data from the Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the ACC/AHA guidelines (CRUSADE) initiative, researchers examined the troponin levels of patients with tSTE in hopes of further stratifying this subgroup of patients.
The CRUSADE initiative included 205,000 patients at more than 500 US sites between 2001 and 2007. Patients had ECG abnormalities suggesting acute coronary syndrome or abnormal serum markers indicating myocardial necrosis. Of 189,000 patients enrolled at the time of this analysis, the researchers found that 11,979 patients had tSTE and had undergone troponin testing. Several factors were associated with tSTE (with "transient" defined as lasting < 10 minutes), including male sex (P < .001) and family history of coronary artery disease (P = .012). Factors associated with reduced likelihood of tSTE included renal insufficiency, hypertension, and history of congestive heart failure (P < .001 for each).
Of the 11,979 patients with tSTE, 8272 (69%) had elevated troponin levels; 3707 patients (31%) had negative troponin markers. The researchers compared patients in the 2 categories and found that patients with tSTE and elevated troponin levels had a 41% increased risk for death during their hospital stay (4.6% vs 2.2%; adjusted odds ratio, 1.41; 95% confidence interval, 1.04 - 1.91;P = .028) compared with patients with tSTE and normal troponin levels.
"Our conclusion was that if a patient with tSTE has abnormal troponin levels, they are in a higher risk group and should be evaluated for more aggressive therapy," said Lee Garvey, MD, medical director of the chest pain evaluation center at the Carolinas Medical Center, Charlotte, North Carolina.
"[The study] identifies a group of patients with a 40% increased risk for acute mortality. Once again, it's a demonstration that troponin is the most important biomarker for acute coronary syndrome," said W. Frank Peacock, MD, director of research for the Cleveland Clinic, Ohio, who attended the conference.
The study was internally funded. Dr. Garvey has disclosed no relevant financial relationships.
American College of Emergency Physicians 38th Annual Scientific Assembly: Abstract 22. Presented October 8, 2007.