High-sensitivity Cardiac Troponin Is Not Associated With Acute Cellular Rejection After Heart Transplantation.

BACKGROUND: Acute cellular rejection (ACR) is common in the first year after cardiac transplantation, and regular surveillance endomyocardial biopsy (EMB) is required. An inexpensive, simple noninvasive diagnostic test would be useful. Prior studies suggest cardiac troponin (cTn) has potential as a "rule-out" test to minimize the use of EMB. Our aim was to determine whether a new high-sensitivity cardiac troponin I (hs-cTnI) assay would have utility as a "rule-out" test for ACR after heart transplantation. METHODS: Blood samples at patient follow-up visits were collected and stored over a period of 5 y. Serum cTnI concentrations were measured using the ARCHITECTSTAT hs-cTnI assay and compared with an EMB performed on the same day. Receiver-operator curve analysis based on mixed-effects logistic regression models that account for repeated measurements in individuals was performed to determine a serum troponin level below which ACR could be reliably excluded. RESULTS: One hundred seventy patients had 883 serum hs-cTnI results paired to a routine surveillance EMB. Fifty-one (6%) EMB showed significant ACR (grade ≥2R). Receiver-operator curve analysis approximated the null hypothesis area under the curve 0.509 (95% CI, 0.428-0.591). Sub-analysis including repeated hs-cTnI levels in a single individual, and early (<3 mo) EMB also showed no diagnostic utility of hs-cTnI measurement (area under the curve 0.512). CONCLUSIONS: In the largest published study to date, we found no association between hs-cTnI concentration and the presence of significant ACR on surveillance EMB. Measurement of hs-cTnI may not be a useful technique for diagnosis or exclusion of ACR after heart transplantation.

High-Sensitivity Cardiac Troponin and New-Onset Heart Failure: A Systematic Review and Meta-Analysis of 67,063 Patients With 4,165 Incident Heart Failure Events.

OBJECTIVES: The aim of this study was to systematically collate and appraise the available evidence regarding the association between high-sensitivity cardiac troponin (hs-cTn) and incident heart failure (HF) and the added value of hs-cTn in HF prediction. BACKGROUND: Identification of subjects at high risk for HF and early risk factor modification with medications such as angiotensin-converting enzyme inhibitors may delay the onset of HF. Hs-cTn has been suggested as a prognostic marker for the incidence of first-ever HF in asymptomatic subjects. METHODS: PubMed, Embase, and Web of Science were systematically searched for prospective cohort studies published before January 2017 that reported associations between hs-cTn and incident HF in subjects without baseline HF. Study-specific multivariate-adjusted hazard ratios (HRs) were pooled using random-effects meta-analysis. RESULTS: Data were collated from 16 studies with a total of 67,063 subjects and 4,165 incident HF events. The average age was 57 years, and 47% were women. Study quality was high (Newcastle-Ottawa score 8.2 of 9). In a comparison of participants in the top third with those in the bottom third of baseline values of hs-cTn, the pooled multivariate-adjusted HR for incident HF was 2.09 (95% confidence interval [CI]: 1.76 to 2.48; p < 0.001). Between-study heterogeneity was high, with an I2 value of 80%. HRs were similar in men and women (2.29 [95% CI: 1.64 to 3.21] vs. 2.18 [95% CI: 1.68 to 2.81]) and for hs-cTnI and hs-cTnT (2.09 [95% CI: 1.53 to 2.85] vs. 2.11 [95% CI: 1.69 to 2.63]) and across other study-level characteristics. Further adjustment for B-type natriuretic peptide yielded a similar HR of 2.08 (95% CI: 1.64 to 2.65). Assay of hs-cTn in addition to conventional risk factors provided improvements in the C index of 1% to 3%. CONCLUSIONS: Available prospective studies indicate a strong association of hs-cTn with the risk of first-ever HF and significant improvements in HF prediction.

High-Sensitivity Cardiac Troponin Concentration and Risk of First-Ever Cardiovascular Outcomes in 154,052 Participants.

BACKGROUND: High-sensitivity assays can quantify cardiac troponins I and T (hs-cTnI, hs-cTnT) in individuals with no clinically manifest myocardial injury. OBJECTIVES: The goal of this study was to assess associations of cardiac troponin concentration with cardiovascular disease (CVD) outcomes in primary prevention studies. METHODS: A search was conducted of PubMed, Web of Science, and EMBASE for prospective studies published up to September 2016, reporting on associations of cardiac troponin concentration with first-ever CVD outcomes (i.e., coronary heart disease [CHD], stroke, or the combination of both). Study-specific estimates, adjusted for conventional risk factors, were extracted by 2 independent reviewers, supplemented with de novo data from PROSPER (Pravastatin in Elderly Individuals at Risk of Vascular Disease Study), then pooled by using random effects meta-analysis. RESULTS: A total of 28 relevant studies were identified involving 154,052 participants. Cardiac troponin was detectable in 80.0% (hs-cTnI: 82.6%; hs-cTnT: 69.7%). In PROSPER, positive associations of log-linear shape were observed between hs-cTnT and CVD outcomes. In the meta-analysis, the relative risks comparing the top versus the bottom troponin third were 1.43 (95% confidence interval [CI]: 1.31 to 1.56) for CVD (11,763 events), 1.67 (95% CI: 1.50 to 1.86) for fatal CVD (7,775 events), 1.59 (95% CI: 1.38 to 1.83) for CHD (7,061 events), and 1.35 (95% CI: 1.23 to 1.48) for stroke (2,526 events). For fatal CVD, associations were stronger in North American studies (p = 0.010) and those measuring hs-cTnT rather than hs-cTnI (p = 0.027). CONCLUSIONS: In the general population, high cardiac troponin concentration within the normal range is associated with increased CVD risk. This association is independent of conventional risk factors, strongest for fatal CVD, and applies to both CHD and stroke.

Human Second Window Pre-Conditioning and Post-Conditioning by Nitrite Is Influenced by a Common Polymorphism in Mitochondrial Aldehyde Dehydrogenase.

Pre-conditioning is an exciting physiological phenomenon that, despite great efforts, has so far resisted translation to mainstream clinical medicine. Many potential triggers (e.g., ischemia of the organ in question or a remote organ, many different drugs) have been investigated, but recent work has implicated activation of mitochondrial aldehyde dehydrogenase (ALDH2) as central to the process. A genetic polymorphism, known as ALDH2*2, is common worldwide (present in up to 40% of Han Chinese people) and produces a functionally different enzyme. The authors used a variety of protocols in the human ischemic forearm model, in participants with both enzyme types, to assess cytoprotection with low-dose sodium nitrite and attempt to further elucidate the role of ALDH2.

Socioeconomic Deprivation and Survival After Heart Transplantation in England: An Analysis of the United Kingdom Transplant Registry.

BACKGROUND: Socioeconomic deprivation (SED) is associated with shorter survival across a range of cardiovascular and noncardiovascular diseases. The association of SED with survival after heart transplantation in England, where there is universal healthcare provision, is unknown. METHODS AND RESULTS: Long-term follow-up data were obtained for all patients in England who underwent heart transplantation between 1995 and 2014. We used the United Kingdom Index of Multiple Deprivation (UK IMD), a neighborhood level measure of SED, to estimate the relative degree of deprivation for each recipient. Cox proportional hazard models were used to examine the association between SED and overall survival and conditional survival (dependant on survival at 1 year after transplantation) during follow-up. Models were stratified by transplant center and adjusted for donor and recipient age and sex, ethnicity, serum creatinine, diabetes mellitus, and heart failure cause. A total of 2384 patients underwent heart transplantation. There were 1101 deaths during 17 040 patient-year follow-up. Median overall survival was 12.6 years, and conditional survival was 15.6 years. Comparing the most deprived with the least deprived quintile, adjusted hazard ratios for all-cause mortality were 1.27 (1.04-1.55; P=0.021) and 1.59 (1.22-2.09; P=0.001) in the overall and conditional models, respectively. Median overall survival and conditional survival were 3.4 years shorter in the most deprived quintile than in the least deprived. CONCLUSIONS: Higher SED is associated with shorter survival in heart transplant recipients in England and should be considered when comparing outcomes between centers. Future research should seek to identify modifiable mediators of this association.

BMPR2 mutations and survival in pulmonary arterial hypertension: an individual participant data meta-analysis.

BACKGROUND: Mutations in the gene encoding the bone morphogenetic protein receptor type II (BMPR2) are the commonest genetic cause of pulmonary arterial hypertension (PAH). However, the effect of BMPR2 mutations on clinical phenotype and outcomes remains uncertain. METHODS: We analysed individual participant data of 1550 patients with idiopathic, heritable, and anorexigen-associated PAH from eight cohorts that had been systematically tested for BMPR2 mutations. The primary outcome was the composite of death or lung transplantation. All-cause mortality was the secondary outcome. Hazard ratios (HRs) for death or transplantation and all-cause mortality associated with the presence of BMPR2 mutation were calculated using Cox proportional hazards models stratified by cohort. FINDINGS: Overall, 448 (29%) of 1550 patients had a BMPR2 mutation. Mutation carriers were younger at diagnosis (mean age 35·4 [SD 14·8] vs 42·0 [17·8] years), had a higher mean pulmonary artery pressure (60·5 [13·8] vs 56·4 [15·3] mm Hg) and pulmonary vascular resistance (16·6 [8·3] vs 12·9 [8·3] Wood units), and lower cardiac index (2·11 [0·69] vs 2·51 [0·92] L/min per m(2); all p<0·0001). Patients with BMPR2 mutations were less likely to respond to acute vasodilator testing (3% [10 of 380] vs 16% [147 of 907]; p<0·0001). Among the 1164 individuals with available survival data, age-adjusted and sex-adjusted HRs comparing BMPR2 mutation carriers with non-carriers were 1·42 (95% CI 1·15-1·75; p=0·0011) for the composite of death or lung transplantation and 1·27 (1·00-1·60; p=0·046) for all-cause mortality. These HRs were attenuated after adjustment for potential mediators including pulmonary vascular resistance, cardiac index, and vasoreactivity. HRs for death or transplantation and all-cause mortality associated with BMPR2 mutation were similar in men and women, but higher in patients with a younger age at diagnosis (p=0·0030 for death or transplantation, p=0·011 for all-cause mortality). INTERPRETATION: Patients with PAH and BMPR2 mutations present at a younger age with more severe disease, and are at increased risk of death, and death or transplantation, compared with those without BMPR2 mutations. FUNDING: Cambridge NIHR Biomedical Research Centre, Medical Research Council, British Heart Foundation, Assistance Publique-Hôpitaux de Paris, INSERM, Université Paris-Sud, Intermountain Research and Medical Foundation, Vanderbilt University, National Center for Advancing Translational Sciences, National Institutes of Health, National Natural Science Foundation of China, and Beijing Natural Science Foundation.

Short-term intravenous sodium nitrite infusion improves cardiac and pulmonary hemodynamics in heart failure patients.

BACKGROUND: Nitrite exhibits hypoxia-dependent vasodilator properties, selectively dilating capacitance vessels in healthy subjects. Unlike organic nitrates, it seems not to be subject to the development of tolerance. Currently, therapeutic options for decompensated heart failure (HF) are limited. We hypothesized that by preferentially dilating systemic capacitance and pulmonary resistance vessels although only marginally dilating resistance vessels, sodium nitrite (NaNO2) infusion would increase cardiac output but reduce systemic arterial blood pressure only modestly. We therefore undertook a first-in-human HF proof of concept/safety study, evaluating the hemodynamic effects of short-term NaNO2 infusion. METHODS AND RESULTS: Twenty-five patients with severe chronic HF were recruited. Eight received short-term (5 minutes) intravenous NaNO2 at 10 µg/kg/min and 17 received 50 µg/kg/min with measurement of cardiac hemodynamics. During infusion of 50 µg/kg/min, left ventricular stroke volume increased (from 43.22±21.5 to 51.84±23.6 mL; P=0.003), with marked falls in pulmonary vascular resistance (by 29%; P=0.03) and right atrial pressure (by 40%; P=0.007), but with only modest falls in mean arterial blood pressure (by 4 mm Hg; P=0.004). The increase in stroke volume correlated with the increase in estimated trans-septal gradient (=pulmonary capillary wedge pressure-right atrial pressure; r=0.67; P=0.003), suggesting relief of diastolic ventricular interaction as a contributory mechanism. Directionally similar effects were observed for the above hemodynamic parameters with 10 µg/kg/min; this was significant only for stroke volume, not for other parameters. CONCLUSIONS: This first-in-human HF efficacy/safety study demonstrates an attractive profile during short-term systemic NaNO2 infusion that may be beneficial in decompensated HF and warrants further evaluation with longer infusion regimens.