Gharacholou, Michael

Abstract Background Guidelines suggest that the diagnosis of acute myocardial infarction (MI) is likely when high concentrations of high-sensitivity cardiac troponin (hs-cTn) are present in the initial sample. These concentration thresholds are much higher than the 99th percentile and are said to provide a high positive predictive value (PPV) for acute MI1. Purpose Evaluate the PPV of recommended baseline hs-cTnT thresholds (>52 and >100 ng/L) for the diagnosis of acute MI from our multi-center United States (US) experience. Methods Retrospective, multicenter (n=22), observational biomarker study involving consecutive, adult patients presenting to the emergency department (ED) in whom at least 1 hs-cTnT measurement was obtained within 12 hours of presentation (CV DataMart Biomarker cohort). The primary endpoint was also evaluated in an adjudicated cohort of consecutive patients presenting to the ED with at least 1 hs-cTnT >99th percentile (ACTION cohort). These cases were adjudicated based on the Fourth Universal Definition of MI by trained physicians. The primary efficacy endpoint was the PPV of acute MI (type 1 or 2), type 1 MI and type 2 MI during index hospitalization using baseline hs-cTnT thresholds of >52 ng/L and >100 ng/L. Results The CV DataMart Biomarker cohort consisted of 143,709 patients, amongst whom 3,003 (2.1%) were diagnosed with acute MI using ICD codes. In the CV DataMart Biomarker cohort, baseline hs-cTnT concentrations of >52 ng/L and >100 ng/L resulted in PPVs of 12% (95% CI: 11, 12) and 17% (95% CI: 17, 19) for acute MI, respectively. In patients with chest pain and baseline hs-cTnT concentrations >52 ng/L, PPV for acute MI was 17% (95% CI: 15, 18), and in those with hs-cTnT concentrations >100 ng/L, PPV was 22% (95% CI: 19, 25). The adjudicated ACTION cohort consisted of 2,107 patients, amongst whom 155 (7.4%) were diagnosed with acute MI including 64 (41%) with type 1 MI and 91 (59%) with type 2 MI. In the ACTION cohort, baseline hs-cTnT concentrations of >52 ng/L and >100 ng/L resulted in PPVs of 46% (95% CI: 40, 53) and 62% (95% CI: 53, 70) for acute MI, respectively. In patients with chest pain and baseline hs-cTnT concentrations >52 ng/L, PPV was 67% (95% CI: 57, 76) for acute MI, 52% (95% CI: 41, 62) for type 1 MI and 15% (95% CI: 8.4, 24) for type 2 MI. In those with chest pain and baseline hs-cTnT concentrations >100 ng/L, PPV was 77% (95% CI: 65, 87) for acute MI, 64% (95% CI: 51, 75) for type 1 MI and 14% (95% CI 6.4, 24) for type 2 MI (Figure). Conclusion Using previously recommended high-risk hs-cTnT thresholds of 52 and 100 ng/L in US patients provides reasonable performance to rule-in acute MI when used in patients with chest pain. When used more broadly across all-comers, the diagnostic performance is poor.

Abstract Background Limited data exist on high-sensitivity cardiac troponin (hs-cTn) for risk-stratification in COVID-19. Methods We conducted a multicenter, retrospective, observational, US-based study of COVID-19 patients undergoing hs-cTnT. Outcomes included short-term mortality (in-hospital and 30-days post-discharge) and a composite of major adverse events, including respiratory failure requiring mechanical ventilation, cardiac arrest, and shock within the index presentation and/or mortality during the index hospitalization or within 30-days post-discharge. Results Among 367 COVID-19 patients undergoing hs-cTnT, myocardial injury was identified in 46%. They had a higher risk for mortality (20% vs 12%, P < 0.0001; unadjusted HR 4.44, 95% CI 2.13–9.25, P < 0.001) and major adverse events (35% vs. 11%, P < 0.0001; unadjusted OR 4.29, 95% CI 2.50–7.40, P < 0.0001). Myocardial injury was associated with major adverse events (adjusted OR 3.84, 95% CI 2.00–7.36, P < 0.0001) but not mortality. Baseline (adjusted OR 1.003, 95% CI 1.00–1.007, P = 0.047) and maximum (adjusted OR 1.005, 95% CI 1.001–1.009, P = 0.0012) hs-cTnT were independent predictors of major adverse events. Most (95%) increases were due to myocardial injury, with 5% (n = 8) classified as type 1 or 2 myocardial infarction. A single hs-cTnT <6 ng/L identified 26% of patients without mortality, with a 94.9% (95% CI 87.5–98.6) negative predictive value and 93.1% sensitivity (95% CI 83.3–98.1) for major adverse events in those presenting to the ED. Conclusions Myocardial injury is frequent and prognostic in COVID-19. While most hs-cTnT increases are modest and due to myocardial injury, they have important prognostic implications. A single hs-cTnT <6 ng/L at presentation may facilitate the identification of patients with a favorable prognosis.