Troponin in early presenters to rule out myocardial infarction

AIMS

Whether a single cardiac troponin measurement can safely rule out myocardial infarction in patients presenting within a few hours of symptom onset is uncertain. The study aim was to assess the performance of troponin in early presenters.

METHODS AND RESULTS

In patients with possible myocardial infarction, the diagnostic performance of a single measurement of high-sensitivity cardiac troponin I at presentation was evaluated and externally validated in those tested ≤3, 4-12, and >12 h from symptom onset. The limit-of-detection (2 ng/L), rule-out (5 ng/L), and sex-specific 99th centile (16 ng/L in women; 34 ng/L in men) thresholds were compared. In 41 103 consecutive patients [60 (17) years, 46% women], 12 595 (31%) presented within 3 h, and 3728 (9%) had myocardial infarction. In those presenting ≤3 h, a threshold of 2 ng/L had greater sensitivity and negative predictive value [99.4% (95% confidence interval 99.2%-99.5%) and 99.7% (99.6%-99.8%)] compared with 5 ng/L [96.5% (96.2%-96.8%) and 99.3% (99.1%-99.4%)]. In those presenting ≥3 h, the sensitivity and negative predictive value were similar for both thresholds. The sensitivity of the 99th centile was low in early and late presenters at 71.4% (70.6%-72.2%) and 92.5% (92.0%-93.0%), respectively. Findings were consistent in an external validation cohort of 7088 patients.

CONCLUSION

In early presenters, a single measurement of high-sensitivity cardiac troponin I below the limit of detection may facilitate the safe rule out of myocardial infarction. The 99th centile should not be used to rule out myocardial infarction at presentation even in those presenting later following symptom onset.

Identifying unmet antithrombotic therapeutic need, and implications for stroke and systemic embolism in atrial fibrillation patients: a population-scale longitudinal study

Aims

Guidelines recommend anticoagulation (AC) in atrial fibrillation (AF) to reduce stroke and systemic embolism (SSE) risk; however, implementation has been slow across many populations. This study aimed to quantify the potential impact of changing prevalence of AF, associated risk, and AC prescribing on SSE hospitalizations and death.

Methods and results

We evaluated temporal trends of AF, CHA2DS2-VASc, antithrombotic prescriptions, SSE hospitalizations, death, and their associations between 2012 and 2018 in a longitudinal cohort of AF patients in Wales UK. Multi-state Markov models were used to estimate expected SSE rates given the AC coverage, adjusting for CHA2DS2-VASc scores. SSE rates were modelled for various past and future AC scenarios. A total of 107 137 AF patients were evaluated (mean age = 74 years, 45% female). AF prevalence increased from 1.75 to 2.22% (P-value <0.001). SSE hospitalizations decreased by 18% (2.34-1.92%, P-value <0.001). Increased AC coverage from 50 to 70% was associated with a 37% lower SSE rate, after adjustment for individual time-dependent CHA2DS2VASc scores. The observed AC increase accounted for approximately 80 fewer SSE hospitalizations per 100 000/year. If 90% AC coverage had been achieved since 2012, an estimated 279 SSE per 100 000/year may have been prevented. Our model also predicts that improving AC coverage to 90% over the next 9 years could reduce annual SSE rates by 9%.

Conclusion

We quantified the relationship between observed AC coverage, estimating the potential impact of variation in the timing of large-scale implementation. These data emphasize the importance of timely implementation and the considerable opportunity to improve clinical outcomes in the Wales-AF population.

Performance of the GRACE 2.0 score in patients with type 1 and type 2 myocardial infarction

AIMS

The Global Registry of Acute Coronary Events (GRACE) score was developed to evaluate risk in patients with myocardial infarction. However, its performance in type 2 myocardial infarction is uncertain.

METHODS AND RESULTS

In two cohorts of consecutive patients with suspected acute coronary syndrome from 10 hospitals in Scotland (n = 48 282) and a tertiary care hospital in Sweden (n = 22 589), we calculated the GRACE 2.0 score to estimate death at 1 year. Discrimination was evaluated by the area under the receiver operating curve (AUC), and compared for those with an adjudicated diagnosis of type 1 and type 2 myocardial infarction using DeLong's test. Type 1 myocardial infarction was diagnosed in 4981 (10%) and 1080 (5%) patients in Scotland and Sweden, respectively. At 1 year, 720 (15%) and 112 (10%) patients died with an AUC for the GRACE 2.0 score of 0.83 [95% confidence interval (CI) 0.82-0.85] and 0.85 (95% CI 0.81-0.89). Type 2 myocardial infarction occurred in 1121 (2%) and 247 (1%) patients in Scotland and Sweden, respectively, with 258 (23%) and 57 (23%) deaths at 1 year. The AUC was 0.73 (95% CI 0.70-0.77) and 0.73 (95% CI 0.66-0.81) in type 2 myocardial infarction, which was lower than for type 1 myocardial infarction in both cohorts (P < 0.001 and P = 0.008, respectively).

CONCLUSION

The GRACE 2.0 score provided good discrimination for all-cause death at 1 year in patients with type 1 myocardial infarction, and moderate discrimination for those with type 2 myocardial infarction.

TRIAL REGISTRATION

ClinicalTrials.gov number, NCT01852123.

Prevalence and clinical implications of valvular calcification on coronary computed tomography angiography

AIMS

Valvular heart disease can be identified by calcification on coronary computed tomography angiography (CCTA) and has been associated with adverse clinical outcomes. We assessed aortic and mitral valve calcification in patients presenting with stable chest pain and their association with cardiovascular risk factors, coronary artery disease, and cardiovascular outcomes.

METHODS AND RESULTS

In 1769 patients (58 ± 9 years, 56% male) undergoing CCTA for stable chest pain, aortic and mitral valve calcification were quantified using Agatston score. Aortic valve calcification was present in 241 (14%) and mitral calcification in 64 (4%). Independent predictors of aortic valve calcification were age, male sex, hypertension, diabetes mellitus, and cerebrovascular disease, whereas the only predictor of mitral valve calcification was age. Patients with aortic and mitral valve calcification had higher coronary artery calcium scores and more obstructive coronary artery disease. The composite endpoint of cardiovascular mortality, non-fatal myocardial infarction, or non-fatal stroke was higher in those with aortic [hazard ratio (HR) 2.87; 95% confidence interval (CI) 1.60-5.17; P < 0.001] or mitral (HR 3.50; 95% CI 1.47-8.07; P = 0.004) valve calcification, but this was not independent of coronary artery calcification or obstructive coronary artery disease.

CONCLUSION

Aortic and mitral valve calcification occurs in one in six patients with stable chest pain undergoing CCTA and is associated with concomitant coronary atherosclerosis. Whilst valvular calcification is associated with a higher risk of cardiovascular events, this was not independent of the burden of coronary artery disease.