Diagnostic and prognostic value of the sex-specific 99th percentile of four high-sensitivity cardiac troponin assays in patients with suspected myocardial infarction

AIMS

High-sensitivity cardiac troponin (hs-cTn) assays are used for detection of myocardial infarction (MI). Ninety-ninth percentiles show wide inter-assay variation. The use of sex-specific cut-offs is recommended as definitory cut-off for MI. We compared diagnostic performance and prognostic value of sex-specific 99th percentiles of four hs-cTn assays in patients with suspected MI.

METHODS AND RESULTS

Concentrations of four hs-cTn assays were measured at presentation and after 3 h in patients with suspected MI. Final diagnoses were adjudicated according to the 4th Universal Definition of MI. Unisex and sex-specific 99th percentiles were evaluated as diagnostic cut-offs following the ESC 0/3 h algorithm. These cut-offs were used in Cox-regression analyses to investigate the association with a composite endpoint of MI, revascularization, cardiac rehospitalization, and death. Non-ST-elevation MI was diagnosed in 368 of 2718 patients. Applying the unisex 99th percentile, Elecsys hs-cTnT provided highest negative predictive value (NPV) of 99.7 and a positive predictive value (PPV) of 75.9. The analysed hs-cTnI assays showed slightly lower NPVs and comparable PPVs [Architect (NPV 98.0, PPV of 71.4); Atellica (NPV 97.7, PPV of 76.1); Pathfast (NPV 97.7, PPV of 66.6)]. Application of sex-specific 99th percentiles did not significantly affect diagnostic performance. Concentrations above 99th percentile were independent predictors for impaired long-term outcome (hazard ratios 1.2-1.5, P < 0.001).

CONCLUSION

We describe a good diagnostic accuracy of four hs-cTn assays using the assay-specific 99th percentile for detection of MI. Application of sex-specific 99th percentiles did neither affect diagnostic performance nor prognostic value significantly. Finally, values above the 99th percentile were associated with poor long-term outcome.

Validation of a 0/1 h Algorithm for Rapid Diagnosis of Myocardial Infarction Using a High-Sensitivity Troponin I Assay

BACKGROUND

Current guidelines recommend 0/1 h algorithms using high-sensitivity cardiac troponin (hs-cTn) for fast diagnosis of myocardial infarction (MI). Yet, for some assays, existing data is limited. We aimed to evaluate the diagnostic performance and the prognostic value of a rapid 0/1 h algorithm for the Access hs-cTnI assay.

METHODS

In consecutive patients presenting with suspected MI, we measured concentrations of Access hs-cTnI at presentation and after 1 hour. Final diagnosis was adjudicated independently by 2 cardiologists. Parameters for diagnostic performance were calculated, applying the recently derived European Society of Cardiology (ESC) 0/1 h algorithm for Access hs-cTnI. Additionally, we assessed the prognostic utility of Access hs-cTnI for the composite end point of all-cause mortality and incident MI at 3 years.

RESULTS

In 1879 patients, 257 non-ST-elevation MIs occurred. Application of the 0/1 h algorithm classified 44.5% as rule-out, 20.3% as rule-in, and triaged 35.1% to the observe group. High rule-out safety was confirmed with a sensitivity of 97.7% (95% CI, 95.0%-99.1%) and a negative predictive value of 99.3% (95% CI, 98.4%-99.7%). Rule-in capacity was moderate with a specificity of 88.0% (95% CI, 86.3%-89.6%) and a positive predictive value of 50.8% (95% CI, 45.7%-55.9%). After exclusion of patients with ST-elevation MI the results showed strong prognostic value, even after adjustment for cardiovascular risk factors and comorbidities, with adjusted hazard ratios of 2.51 (95% CI, 1.56-4.04) in the observe and 3.55 (95% CI, 2.18-5.79) in the rule-in group for the composite end point of all-cause mortality and incident MI at 3 years, compared to ruled-out patients.

CONCLUSION

The ESC 0/1 h algorithm for Access hs-cTnI allows safe and efficient triage of patients with suspected MI and has strong prognostic utility up to 3 years after the initial evaluation.

Diagnostic performance of a device for acoustic heart sound analysis in patients with suspected myocardial infarction

BACKGROUND

As only a small proportion of patients with chest pain suffers from myocardial infarction (MI), safe rule-out of MI is of immense importance. Recently an ultrasensitive microphone performing diastolic heart sound analysis (CADScorSystem) for rule-out of coronary artery disease (CAD) has emerged. In this explorational study, we aimed to evaluate the feasibility of the CADScorSystem for diagnosis of MI in the setting of a large emergency department.

METHODS

Patients presenting to the emergency department with suspected MI were included. Acoustic heart sound analysis was performed in all patients and automated CAD-score values were calculated via a device-embedded algorithm, which also requires inclusion of three clinical variables: age, sex and presence of hypertension. Patients additionally received serial high-sensitive troponin T measurement measurements to assess the final diagnosis according to third Universal Definition of Myocardial Infarction applying the European Society of Cardiology 0 hour/3 hours algorithm. Diagnostic parameters for MI, considering different CAD-score cut-offs, were computed.

RESULTS

Of 167 patients, CAD-scores were available in 61.1%. A total of eight patients were diagnosed with MI. At a cut-off value of <20, CAD-score had a negative predictive value (NPV) of 90.7 (78.4-96.3). The corresponding positive predictive value (PPV) was 6.8 (2.7-16.2). For the adjusted CAD-score (age, sex, hypertension), at a cut-off value of <20, NPV was 90.0 (59.6-99.5) with a PPV of 10.8 (5.3-20.6).

CONCLUSION

In this explorative analysis, a transcutaneous ultrasensitive microphone for heart sound analysis resulted in a high NPV analogous to the findings in rule-out of stable CAD in elective patients yet inferior to serial high-sensitivity cardiac troponin measurements and does not seem feasible for application in an emergency setting for rule-out of MI.

TRIAL REGISTRATION NUMBER

NCT02355457.

Clinical application of the 4th Universal Definition of Myocardial Infarction

AIMS

The recently released 4th version of the Universal Definition of Myocardial Infarction (UDMI) introduces an increased emphasis on the entities of acute and chronic myocardial injury. We applied the 4th UDMI retrospectively in patients presenting to the emergency department with symptoms potentially indicating myocardial infarction (MI) to investigate its effect on diagnosis and prognosis.

METHODS AND RESULTS

We included 2302 patients presenting to the emergency department with symptoms suggestive of MI. The final diagnosis was adjudicated sequentially according to the 3rd and 4th UDMI. Reclassification after readjudication was assessed. Established diagnostic algorithms for patients with suspected MI were applied to compare diagnostic accuracy. All patients were followed to assess mortality, recurrent MI, revascularization, and rehospitalization to investigate the effect of the 4th UDMI on prognosis. After readjudication, 697 patients were reclassified. Most of these patients were reclassified as having acute (n = 78) and chronic myocardial injury (n = 585). Four hundred and thirty-four (18.9%) patients were diagnosed with MI, compared with 501 (21.8%) MIs when adjudication was based on the 3rd UDMI. In the non-MI population, patients with myocardial injury (n = 663) were older, more often female and had worse renal function compared with patients without myocardial injury (n = 1205). Application of diagnostic algorithms for patients with suspected MI revealed a high accuracy after readjudication. Reclassified patients had a substantially higher rate of cardiovascular events compared with not-reclassified patients, particularly patients reclassified to the category of myocardial injury.

CONCLUSION

By accentuating the categories of acute and chronic myocardial injury the 4th UDMI succeeds to identify patients with higher risk for cardiovascular events and poorer outcome and thus seems to improve risk assessment in patients with suspected MI. Application of established diagnostic algorithms remains safe when using the 4th UDMI.

Differences in measurement of high-sensitivity troponin in an on-demand and batch-wise setting

BACKGROUND

Most studies assessing the diagnostic value of high-sensitivity troponin in the diagnosis of myocardial infarction used batch-wise analyses of frozen samples for high-sensitivity troponin measurements. Whether the accuracy of these batch-wise high-sensitivity troponin measurements described in diagnostic studies is comparable to clinical routine is unknown.

METHODS

We enrolled 937 patients presenting with suspected myocardial infarction in this prospective cohort study. Measurements of high-sensitivity troponin I (Abbott Architect) and high-sensitivity troponin T (Roche) were performed in two settings: (a) on-demand in clinical routine using fresh blood samples; and (b) in batches using frozen blood samples from the same individuals at three timepoints (0 hours, 1 hour and 3 hours after presentation).

RESULTS

Median troponin levels were not different between on-demand and batch-wise measurements. Troponin levels in the range of 0 to 40 ng/L showed a very high correlation between the on-demand and batch setting (Pearson correlation coefficient (r) was 0.92-0.95 for high-sensitivity troponin I and 0.96 for high-sensitivity troponin T). However, at very low troponin levels (0 to 10 ng/L) correlation between the two settings was moderate (r for high-sensitivity troponin I 0.59-0.66 and 0.65-0.69 for high-sensitivity troponin T). Application of guideline-recommended rapid diagnostic algorithms showed similar diagnostic performance with both methods.

CONCLUSIONS

Overall on-demand and batch-wise measurements of high-sensitivity troponin provided similar results, but their correlation was moderate, when focusing on very low troponin levels. The application of rapid diagnostic algorithms was safe in both settings.Trial Registration: www.clinicaltrials.gov (NCT02355457).

Right bundle branch block in patients with suspected myocardial infarction

Aims:

The new European Society of Cardiology guideline for ST-segment elevation myocardial infarction recommends that left and right bundle branch block should be considered equal for recommending urgent angiography in patients with suspected myocardial infarction. We aimed to evaluate this novel recommendation in two prospective studies of patients with suspected myocardial infarction.

Methods and results:

We included 4067 patients presenting to the emergency department with suspected myocardial infarction. All patients had an ECG recorded immediately upon admission. Patients were classified as having right bundle branch block (RBBB), left bundle branch block (LBBB), bifascicular block (BFB) or no bundle branch block. All patients were followed for up to two years to assess mortality. In the overall population 125 (3.1%) patients had RBBB, 281 (6.9%) LBBB and 60 (1.5%) BFB. The final diagnosis of myocardial infarction was adjudicated in 20.8% (RBBB), 28.5% (LBBB), 23.3% (BFB) and 21.6% (no complete block) of patients. The mortality rate after one year was 10.7% (RBBB), 7% (LBBB), 17.5% (BFB) and 3.2% (no complete block). The adjusted hazard ratios were 1.29 (95% confidence interval (CI) 0.71–2.34; P=0.40) for RBBB, 1.71 (95% CI 1.17–2.50; P=0.006) for LBBB and 2.27 (95% CI 1.28–4.05; P=0.005) for BFB.

Conclusion:

Our results support the new European Society of Cardiology ST-segment elevation myocardial infarction guideline describing RBBB as a high risk for mortality in patients with suspected myocardial infarction. However, the data challenge the concept of RBBB as a trigger of acute angiography because the likelihood of myocardial infarction in a chest pain unit setting is equally frequent in patients without bundle branch block.

Relations of Sex to Diagnosis and Outcomes in Acute Coronary Syndrome

BACKGROUND

The atypical presentation of women with acute coronary syndrome (ACS) has been related to delayed diagnosis and treatment, which may explain worse outcome compared with men.

METHODS AND RESULTS

We analyzed pooled data of 2520 patients of 2 prospective cohorts in terms of differences in presentation and management of women and men suggestive of ACS. Using logistic regression, we established 2 diagnostic models and tested their diagnostic performance in both sexes separately. Sex-specific differences in management of patients with ACS were ascertained and a 2-year follow-up was performed. Women were older than men (median 67 versus 61 years, P=0.001), had more often dyspnea (22% versus 18%, P=0.024), nausea or vomiting (26% versus 16%, P=0.001) and radiating chest pain (47% versus 40%, P=0.001). Classical risk factors (smoking, diabetes mellitus, dyslipidemia or known coronary artery disease) were less frequent in women. Diagnostic models showed no significant sex-related differences in diagnostic performance in a "first contact" setting (medical history and symptoms) or after "complete triage" (including ECG and biomarkers). Women with ACS underwent coronary angiography (73.8% versus 84.3%, P<0.001) and revascularization (53.8% versus 70.1%, P<0.001) less frequently. Two-year incidence of myocardial infarction and death was similar in both sexes, but revascularization and cardiac rehospitalization were more frequent in men.

CONCLUSIONS

In a large cohort of patients with suspected ACS, sex differences in clinical presentation did not impair diagnostic accuracy. Two-year outcomes were comparable. Our findings suggest a benefit of chest pain units to minimize sex differences in ACS management and prognosis.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifiers: NCT02355457 (BACC), NCT03227159 (stenoCardia).

Cardiovascular Biomarkers in Hypertensive Patients with Medical Treatment-Results from the Randomized TEAMSTA Protect I Trial

BACKGROUND

High blood pressure (BP) is associated with an increased rate of cardiovascular events and mortality. Cardiovascular biomarkers are able to predict long-term risk in the general population, particularly in diseased cohorts. We undertook an investigation of the effect of 2 different antihypertensive treatments on cardiovascular biomarkers in a randomized trial.

METHODS

The TEAMSTA study included 481 hypertensive patients. They were randomized to either 80-mg telmisartan + 5-mg amlodipine (TA) or 40-mg olmesartan + 12.5-mg hydrochlorothiazide (OH). The trial was performed as a prospective, randomized, double-blinded, controlled, single-center study. We measured BP, high-sensitivity cardiac troponin I (hs-cTnI), high-sensitivity cardiac troponin T (hs-cTnT), B-type natriuretic peptide (BNP), and N-terminal-pro-BNP (NT-proBNP) before randomization and after 6 months.

RESULTS

Individuals were randomized into 2 groups: 230 individuals to the OH-group and 251 to the TA-group. After 6 months of treatment, a reduction in BP (systolic/diastolic) was seen, from 135.2/85.2 mmHg to 122.5/75.7 mmHg with similar effects in both groups. hs-cTnT concentrations were measureable in 26.2% of the study population, while hs-cTnI was detected in 98.3%. hs-cTnI concentrations were significantly reduced from 4.6 to 4.2 ng/L in the overall population, from 4.7 to 4.4 ng/L in the OH-group, and from 4.6 to 4.0 ng/L in the TA-group (all P < 0.001). No significant changes of hs-cTnT were observed. BNP and NT-proBNP concentrations decreased from 15.0 to 12.4 ng/L (P < 0.001) and from 64.8 to 53.3 ng/L (P < 0.001), respectively, after 6 months.

CONCLUSIONS

The reduction in BP was associated with a decrease of high-sensitivity troponin I, BNP, and NT-proBNP concentrations, which might represent a cardiovascular risk reduction.

CLINICAL TRIAL REGISTRATION

EudraCT 2009-017010-68.

Early diagnosis of acute myocardial infarction using high-sensitivity troponin I

Objective

There is a clinical need for early and accurate diagnosis of acute myocardial infarction (AMI). Current European Society of Cardiology (ESC) guidelines recommend diagnosis of non-ST-elevation AMI based on serial troponin measurements. We aimed to challenge the ESC guidelines using 1) a high-sensitivity troponin I (hs-TnI) baseline cutoff, 2) an absolute hs-TnI change after 1 hour and 3) additional application of an ischemic ECG.

Methods

1,516 patients with suspected AMI presenting to the emergency department were included. Hs-TnI was measured directly at admission, after 1 and 3 hours. We investigated baseline concentrations, absolute changes of hs-TnI and additional application of an ischemic ECG to diagnose AMI. A positive predictive value (PPV) of more than 85% was targeted.

Results

The median age of the study population was 65 years; 291 patients were diagnosed with AMI. The PPV of the 3-hours ESC algorithm was 85.5% (CI 79.7, 90.1) and 65.8% (CI 60.5,70.8) for the 1-hour algorithm. Using a high baseline hs-TnI concentration of 150 ng/L resulted in a PPV of 87.8% (CI 80.9,92.9). Alternatively, a hs-TnI change of 20 ng/L after 1 hour, resulted in a PPV of 86.5% (80.9,91.0), respectively for the diagnosis of AMI. Additional use of an ischemic ECG increased the PPV to 90.5% (CI 83.2,95.3), while reducing the efficacy.

Conclusion

The diagnosis of AMI based on hs-TnI is challenging. The application of absolute hs-TnI changes after 1 hour may facilitate rapid rule-in of patients.

Trial registration

www.clinicaltrials.gov (NCT02355457).

Challenging the 99th percentile: A lower troponin cutoff leads to low mortality of chest pain patients

BACKGROUND

Rule-out of non-ST-elevation myocardial infarction is based on consecutive measurements of cardiac troponins using the 99th percentile of the respective assay as cutoff. The new ESC guidelines alternatively offer rapid 1h algorithms with lower cutoffs than the 99th percentile for rule-out of non-ST-elevation myocardial infarction. We aimed to compare a recently introduced 1h algorithm based on a high-sensitivity cardiac troponin I (hs-TnI) cutoff of 6ng/L at 0h and 1h to the current standard of care using the 99th percentile (27ng/L) as cutoff with reference to follow-up events in a large chest pain cohort.

METHODS

Hs-TnI was measured at three time points (0h, 1h and 3h) in 1625 patients presenting with suspected myocardial infarction to the emergency department of the University-Medical Center Hamburg-Eppendorf. Seventy-five patients with ST-elevation myocardial infarction were excluded from the analysis. All-cause mortality, cardiac death, acute myocardial infarction, revascularization and cardiac rehospitalization after 12months were assessed.

RESULTS

Patients ruled out by the 1h algorithm showed significantly less cardiac rehospitalizations (12.84% vs. 17.66%; p<0.001), and overall mortality (1.30% vs 3.46%, p<0.001) compared to using the 99th percentile as cutoff. The majority of deaths were caused by non-cardiac reasons. Cardiac deaths were rare using the 1h algorithm (0.21%).

CONCLUSION

The commonly used 99th percentile as cutoff neglects patients with a high risk in the setting of acute chest pain.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT02355457).

Immediate Rule-Out of Acute Myocardial Infarction Using Electrocardiogram and Baseline High-Sensitivity Troponin I

AIMS

Serial measurements of high-sensitivity troponin are used to rule out acute myocardial infarction (AMI) with an assay specific cutoff at the 99th percentile. Here, we evaluated the performance of a single admission troponin with a lower cutoff combined with a low risk electrocardiogram (ECG) to rule out AMI.

METHODS

Troponin I measured with a high-sensitivity assay (hs-TnI) was determined at admission in 1040 patients presenting with suspected AMI (BACC study). To rule out AMI we calculated the negative predictive value (NPV) utilizing the optimal hs-TnI cutoff combined with a low risk ECG. The results were validated in 3566 patients with suspected AMI [2-h Accelerated Diagnostic Protocol to Assess Patients With Chest Pain Symptoms Using Contemporary Troponins as the Only Biomarker (ADAPT) studies]. Patients were followed for 6 or 12 months.

RESULTS

184 of all patients were diagnosed with AMI. An hs-TnI cutoff of 3 ng/L resulted in a NPV of 99.3% (CI 97.3-100.0), ruling out 35% of all non-AMI patients. Adding the information of a low risk ECG resulted in a 100% (CI 97.5-100.0) NPV (28% ruled out). The 2 validation cohorts replicated the high NPV of this approach. The follow-up mortality in the ruled out population was low (0 deaths in BACC and Stenocardia, 1 death in ADAPT).

CONCLUSIONS

A single hs-TnI measurement on admission combined with a low risk ECG appears to rule out AMI safely without need for serial troponin testing.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT02355457).