Insights into the change in brain natriuretic peptide after ST-elevation myocardial infarction (STEMI): why should it be better than baseline?This paper is one of a selection of papers published in this Special Issue, entitled Young Investigators' Forum

Early changes in N-terminal pro-brain natriuretic peptide levels predict new-onset heart failure in patients with STEMI

BACKGROUND

Previous studies suggested that N-terminal pro-brain natriuretic peptide (NT-proBNP) level is a powerful independent predictor of death or heart failure (HF) when measured at admission in patients with chest pain or acute coronary syndrome. Little is known about the role of NT-proBNP level measured during a hospitalization for ST segment elevation myocardial infarction (STEMI) in predicting clinical outcomes. We evaluated the optimal NT-proBNP timing (admission, 72 hours, or delta [Δ] NT-proBNP [72 hours minus admission]) to predict 1-year new-onset HF in STEMI patients.

METHODS

We measured NT-proBNP levels at admission and 72 hours in 72 patients with STEMI. HF events were adjudicated and defined as hospitalization for HF or need for new initiation of a loop diuretic at 1-year follow-up. Values are presented as medians and interquartile range or frequencies (%) as appropriate. Cox regression analysis was used to determine predictors of adverse events. A receiver-operative-curve was constructed to identify the discriminative value and optimal cut-off points for NT-proBNP.

RESULTS

Patients (age 56 [49-64] years, males 59 [82%]) were followed for a median duration of 365 [180-365] days. HF events were recorded in 9 (12.5%) patients. NT-proBNP values at admission, 72 hours, and ΔNT-proBNP were 89 (26-268) pg/mL, 452 (223-1064) pg/mL, and 283 (68-686) pg/mL, respectively. NT-proBNP at 72 hours and ΔNT-proBNP, but not admission NT-proBNP predicted new-onset HF events at follow-up (P=0.03, P=0.002 and P=0.89, respectively). The optimal area under the curve of 0.771 (95%, CI [0.630-0.912], P= 0.009) and cut-off value of 830 pg/mL (sensitivity 79%; specificity 76%) were found for NT-proBNP at 72 hours. The Kaplan-Meier survival curves for NT-proBNP at 72 hours dichotomized above and below this cut-off value, confirmed NT-proBNP at 72 hours >830 pg/mL as predictive of HF events (log-rank statistic = 8.688, P=0.003).

CONCLUSIONS

NT-proBNP level at 72 hours and ΔNT-proBNP (72 hours minus admission), but not at time of admission, predicted HF events in patients following STEMI.

NT-proBNP during and after primary PCI for improved scheduling of early hospital discharge

Background

The Zwolle Risk Score (ZRS) identifies primary percutaneous coronary intervention (PPCI) patients at low mortality risk, eligible for early discharge. Recently, this score was improved by adding baseline NT-proBNP. However, the optimal timepoint for NT-proBNP measurement is unknown.

Methods

PPCI patients in the On-Time 2 study were candidates. The ZRS and NT-proBNP levels on admission, at 18–24 h, at 72–96 h, and the change in NT-proBNP from baseline to 18–24 h (delta NT-proBNP) were determined. We investigated whether addition of the different NT-proBNP measurements to the ZRS improves the prediction of 30-day mortality. Based on cut-off values reflecting zero mortality at 30 d, patients who potentially could be discharged early were identified and occurrence of major adverse cardiac events (MACE) and major bleeding until 10 d was registered.

Results

845 patients were included. On multivariate analyses, NT-proBNP at baseline (HR 2.09, 95% CI 1.59–2.74, p < 0.001), at 18–24 h (HR 6.83, 95% CI 2.94–15.84), and at 72–96 h (HR 3.32, 95% CI 1.22–9.06) independently predicted death at 30 d. Addition of NT-proBNP to the ZRS improved prediction of mortality, particularly at 18–24 h (net reclassification index 29%, p < 0.0001, integrated discrimination improvement 17%, p < 0.0001). Based on ZRS (<2) or NT-proBNP at 18–24 h (<2500 pg/ml) 75% of patients could be targeted for early discharge at 48 h, with expected re-admission rates of 1.2% due to MACE and/or major bleeding.

Conclusions

NT-proBNP at different timepoints improves prognostication of the ZRS. Particularly at 18–24 h post PPCI, the largest group of patients that potentially could be discharged early was identified.

Electronic supplementary material

The online version of this article (doi: 10.1007/s12471-016-0935-2) contains supplementary material, which is available to authorized users.

Predictive value of NT-proBNP for 30-day mortality in patients with non-ST-elevation acute coronary syndromes: a comparison with the GRACE and TIMI risk scores

Background

The biomarker N-terminal pro-brain natriuretic peptide (NT-proBNP) predicts outcome in patients with non-ST-elevation acute coronary syndromes (NSTE-ACS). Whether NT-proBNP has incremental prognostic value beyond established risk strategies is still questionable.

Purpose

To evaluate the predictive value of NT-proBNP for 30-day mortality over and beyond the Global Registry of Acute Coronary Events (GRACE) and Thrombolysis In Myocardial Infarction (TIMI) risk scores in patients with NSTE-ACS.

Methods

Patients included in our ACS registry were candidates. NT-proBNP levels on admission were measured and the GRACE and TIMI risk scores were assessed. We compared the predictive value of NT-proBNP to both risk scores and evaluated whether NT-proBNP improves prognostication by using receiver operator curves and measures of discrimination improvement.

Results

A total of 1324 patients were included and 50 patients died during follow-up. On logistic regression analysis NT-proBNP and the GRACE risk score (but not the TIMI risk score) both independently predicted mortality at 30 days. The predictive value of NT-proBNP did not differ significantly compared to the GRACE risk score (area under the curve [AUC]) 0.85 vs 0.87 p=0.67) but was considerably higher in comparison to the TIMI risk score (AUC 0.60 p<0.001). Adjustment of the GRACE risk score by adding NT-proBNP did not improve prognostication: AUC 0.86 (p=0.57), integrated discrimination improvement 0.04 (p=0.003), net reclassification improvement 0.12 (p=0.21).

Conclusion

In patients with NSTE-ACS, NT-proBNP and the GRACE risk score (but not the TIMI risk score) both have good and comparable predictive value for 30-day mortality. However, incremental prognostic value of NT-proBNP beyond the GRACE risk score could not be demonstrated.

Multi-marker network in ST-elevation myocardial infarction patients undergoing primary percutaneous coronary intervention: when and what to measure

BACKGROUND

Data on the correlations between biomarkers to suggest cost-effective multi-marker (MM) panels predictive for ST-elevation myocardial infarction (STEMI) patients are lacking. We sought to explore the relationship between cardiac troponin I (cTnI), C-reactive protein (CRP), B-type natriuretic peptide (BNP), and chromogranin A (CgA) accounting for biomarkers' profiles detected within 48h from successful primary percutaneous coronary intervention (PPCI).

METHODS

In 73 STEMI patients cTnI, CRP, BNP, and CgA were measured before PPCI and 6, 24, and 48h later. STATIS methods generalizing Principal Component Analysis on three-way data sets were employed to extract information about: 1) similarities between patients, 2) contribution of each time of sampling and 3) correlations between biomarkers' profiles.

RESULTS

STEMI patients who underwent successful PPCI emerged to have a homogeneous profile tailored on biomarkers' evaluation within 48h. Their measurements at 24h contributed the most variability and information both to patients' and to biomarkers' profiles. BNP and cTnI were highly correlated and explained the 40.1% of the total variance, whereas CgA resulted independent and explained the 26.3% of the total variance.

CONCLUSIONS

Markers' measurements at 24h after PPCI contributed most information to the definition of patients' profile. BNP and cTnI resulted interchangeable in a MM panel for reporting about the extent of necrosis.

Established and novel biomarkers in ST-elevation myocardial infarction

Cardiac biomarkers assist in the diagnosis of and risk stratification in acute coronary syndromes. In ST-elevation myocardial infarction (STEMI), rapid diagnosis and initiation of reperfusion via primary percutaneous coronary intervention or fibrinolysis is often based on the clinical history and presenting ECG, but measurement of biomarkers in the early and/or late phases of STEMI may allow the selection of patients who are at increased or decreased risk of subsequent complications. Although the measurement of only three biomarkers (troponin, natriuretic peptides and C-reactive protein) are currently included in practice guidelines, more than 20 other novel cardiac biomarkers have been proposed to provide improved risk stratification after a STEMI.

Predicting chronic left ventricular dysfunction 90 days after ST-segment elevation myocardial infarction: An Assessment of Pexelizumab in Acute Myocardial Infarction (APEX-AMI) Substudy

OBJECTIVES

The purpose of this study was to determine predictors of 90-day left ventricular function following acute ST-segment elevation myocardial infarction (STEMI) using variables from clinical presentation, biomarker testing, and cardiovascular magnetic resonance imaging (CMR).

BACKGROUND

Identifying patients with acute STEMI who experience adverse remodeling and develop left ventricular dysfunction 3 months post-MI is a priority for guiding subsequent therapy.

METHODS

The Assessment of Pexelizumab in Acute Myocardial Infarction trial tested pexelizumab treatment in STEMI patients presenting within 6 hours of symptom onset who were to undergo primary percutaneous coronary intervention. We studied 64 patients within this trial according to a prespecified substudy that included paired core laboratory delayed-enhancement CMR at days 3 and 90 as well as plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP; in picograms per milliliter) measured at randomization and 24 hours. A multivariable model predicting day 90 left ventricular ejection fraction (LVEF) was developed from clinical, biomarker, and imaging findings.

RESULTS

Patients had a median age of 60 years (52-68), 89% were male, and 60% had anterior STEMI. Time from symptom onset to percutaneous coronary intervention was 3 hours. The median baseline LVEF was 48% (38%-56%) and was 50% (40%-54%) at 90 days: 7 patients (11%) had an LVEF <35% at 90 days. Patients with a lower 90-day LVEF (as a continuous variable) had a higher 24-hour NT-proBNP (P = .02) and a larger baseline infarct size by CMR (median 15% LV [8%-20% LV]) (P < .01). Microvascular obstruction (no reflow) was greater as measured by CMR (median 2.8% [1.4%-6.1%]) in patients with a lower 90-day LVEF (P < .01). Median baseline and 24-hour NT-proBNP levels were 94 pg/mL (54-292 pg/mL) and 1,448 pg/mL (958-2,599 pg/mL), respectively. In a multivariable model with clinical, biomarker, and imaging variables, only 3 variables independently predicted 90-day LVEF: 24-hour NT-proBNP, baseline CMR infarct size, and microvascular obstruction.

CONCLUSIONS

Three key pathophysiologic variables of the post-STEMI myocardium measuring baseline infarct size and the extent of microvascular obstruction on CMR and wall tension (24-hour NT-proBNP) independently predicted 90-day LVEF. Further studies linking these measures with earlier use of clinical therapies may be warranted.