NT pro-B-type natriuretic peptide levels are related to microvascular reperfusion in patients undergoing direct percutaneous transluminal coronary angioplasty for anterior ST-segment elevation myocardial infarction

Do cardiac biomarkers NT-proBNP and hsTnT predict microvascular events in patients with type 2 diabetes? Results from the ADVANCE trial

OBJECTIVE

We investigated microvascular event risk in people with type 2 diabetes and assessed whether N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity troponin T (hsTnT) improved prediction.

RESEARCH DESIGN AND METHODS

We performed a case-cohort study, including 439 incident cases of microvascular events (new or worsening nephropathy or retinopathy) and 2,946 noncase subjects identified from participants in the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) trial. NT-proBNP and hsTnT were measured in stored plasma samples using automated commercial assays.

RESULTS

After adjustment for age, sex, and randomized treatment, the hazard ratios for microvascular events per 1-SD increase in the log-transformed hsTnT and NT-proBNP were 1.67 (95% CI 1.51-1.85) and 1.63 (1.44-1.84), respectively. After further adjustment for classical and diabetes-related cardiovascular disease risk factors, the hazard ratios attenuated to 1.40 (1.24-1.58) and 1.41 (1.24-1.60), respectively. While the C statistic did not improve on addition of hsTnT or NT-proBNP for the total microvascular end point, a combination of both markers improved the prediction of nephropathy (P = 0.033) but not retinopathy (P = 0.72). The corresponding net reclassification indices in a three-risk category model (<10%, 10-15%, and >15% 5-year risk) for all microvascular events were 7.31% (95% CI 2.24-12.79) for hsTNT addition, 6.23% (1.74-11.5) for NT-proBNP addition, and 7.1% (1.5-12.9) for both markers together.

CONCLUSIONS

These data suggest that cardiac biomarkers moderately improve microvascular event risk prediction, in particular the risk of nephropathy. Further studies examining the value of this approach for trial design and clinical use are warranted.

Association of 25-hydroxyvitamin D deficiency with NT-pro BNP levels in patients with acute myocardial infarction: a cross-sectional analysis

Background

Nutritional vitamin D deficiency is an emerging risk factor for acute myocardial infarction (AMI) and heart failure. The association of 25-hydroxyvitamin D levels with N-terminal pro B-type natriuretic peptide (NT-proBNP), a robust prognostic marker for post-AMI mortality and heart failure, is unknown and could illuminate a potential pathway for adverse outcomes among post-AMI patients with 25-hydroxyvitamin D deficiency.

Methods

In a cross-sectional analysis, we studied 238 AMI patients from 21 U.S. centers to test the association of nutritional vitamin D (25-hydroxyvitamin D [25(OH)D]) deficiency with NT-proBNP levels. Levels of 25(OH)D levels were categorized as normal (≥30 ng/mL), insufficient (>20 - <30 ng/mL), deficient (>10 - ≤20 ng/mL), or severely deficient (≤10 ng/mL).

Results

Low 25(OH)D levels were found in 95.7% of AMI patients. No significant trends for higher mean baseline log NT-proBNP levels in severely deficient (6.9 ± 1.3 pg/mL), deficient (6.9 ± 1.2 pg/mL), and insufficient (6.9 ± 0.9 pg/ml) groups were observed as compared with patients having normal (6.1 ± 1.7 pg/mL) levels, P = 0.17. Findings were similar in the subset of patients who had follow-up NT-proBNP levels drawn at one month. In multivariate regression modeling, after adjusting for multiple covariates, 25(OH)D was not associated with NT-proBNP.

Conclusions

Potential associations between nutritional vitamin D deficiency and prognosis in the setting of AMI are unlikely to be mediated through NT-proBNP pathways. Future studies should examine other mechanisms, such as inflammation and vascular calcification, by which 25(OH)D deficiency could mediate adverse outcomes post-AMI.