Third universal definition of myocardial infarction

Effect of serelaxin on cardiac, renal, and hepatic biomarkers in the Relaxin in Acute Heart Failure (RELAX-AHF) development program: correlation with outcomes

OBJECTIVES

The aim of this study was to assess the effects of serelaxin on short-term changes in markers of organ damage and congestion and relate them to 180-day mortality in patients with acute heart failure.

BACKGROUND

Hospitalization for acute heart failure is associated with high post-discharge mortality, and this may be related to organ damage.

METHODS

The Pre-RELAX-AHF (Relaxin in Acute Heart Failure) phase II study and RELAX-AHF phase III study were international, multicenter, double-blind, placebo-controlled trials in which patients hospitalized for acute heart failure were randomized within 16 h to intravenous placebo or serelaxin. Each patient was followed daily to day 5 or discharge and at days 5, 14, and 60 after enrollment. Vital status was assessed through 180 days. In RELAX-AHF, laboratory evaluations were performed daily to day 5 and at day 14. Plasma levels of biomarkers were measured at baseline and days 2, 5, and 14. All-cause mortality was assessed as a safety endpoint in both studies.

RESULTS

Serelaxin reduced 180-day mortality, with similar effects in the phase II and phase III studies (combined studies: N = 1,395; hazard ratio: 0.62; 95% confidence interval: 0.43 to 0.88; p = 0.0076). In RELAX-AHF, changes in markers of cardiac (high-sensitivity cardiac troponin T), renal (creatinine and cystatin-C), and hepatic (aspartate transaminase and alanine transaminase) damage and of decongestion (N-terminal pro-brain natriuretic peptide) at day 2 and worsening heart failure during admission were associated with 180-day mortality. Serelaxin administration improved these markers, consistent with the prevention of organ damage and faster decongestion.

CONCLUSIONS

Early administration of serelaxin was associated with a reduction of 180-day mortality, and this occurred with fewer signs of organ damage and more rapid relief of congestion during the first days after admission.

Coronary artery disease in patients clinically diagnosed with myocardial infarction in the medical intensive care unit

PURPOSE

The purpose of this study is to compare the clinical characteristics and outcomes of patients with and without coronary artery disease (CAD) confirmed by coronary angiography in critically ill patients clinically diagnosed with myocardial infarction.

MATERIALS AND METHODS

This retrospective observational study involved 56 patients who were clinically diagnosed with myocardial infarction and subsequently underwent coronary angiography during their intensive care unit stay.

RESULTS

Only 18 patients (32%) were finally confirmed to have CAD by coronary angiography. There were no significant differences in laboratory findings and clinical outcomes between patients with and without CAD. However, patients who developed shock (P = .009) and needed vasopressor support (P = .021) were less likely to be diagnosed with CAD. In addition, regional wall motion abnormality on echocardiography was more frequently observed in patients with CAD (P = .072). In a multiple logistic regression analysis, male sex (adjusted odds ratio [OR], 5.093; 95% confidence interval [CI], 1.177-22.037) and focal hypokinesia on echocardiography (adjusted OR, 5.134; 95% CI, 1.071-24.614) were independently associated with CAD. However, development of shock was inversely associated with CAD (adjusted OR, 0.107; 95% CI, 0.019-0.606).

CONCLUSION

Coronary angiography in critically ill patients should only be performed in highly selected patients with predicting factors for CAD.

Frequency, causes, predictors, and clinical significance of peri-procedural myocardial infarction following percutaneous coronary intervention

AIMS

Peri-procedural myocardial infarction (MI) is a not infrequent complication of percutaneous coronary intervention (PCI), but conflicting information exists regarding incidence and prognostic impact of this event. We investigated frequency, causes, predictors, and clinical relevance of peri-procedural MI, using a large database.

METHODS AND RESULTS

We pooled individual patient-level data from 11 PCI studies in which peri-procedural creatine kinase-MB mass was routinely measured and mortality data were prospectively collected. Among 23 604 patients from 11 studies, 1677 {7.1% [95% confidence interval (CI) 6.8-7.5%]} had peri-procedural MI. The most common mechanism of peri-procedural MI was side-branch occlusion. Independent predictors of peri-procedural MI were older age, female gender, diabetes, hypertension, renal dysfunction, multivessel disease, left anterior descending artery disease, left main disease, bifurcation lesion, long lesion, drug-eluting stents, and number of stents. Follow-up varied from 1 year to 5 years. In a crude analysis, patients with peri-procedural MI had significantly a higher risk of mortality than those without peri-procedural MI [hazard ratio (HR) 1.47; 95% CI 1.24-1.74]. After adjustment for baseline covariates, peri-procedural MI was associated with an increased risk of mortality (HR 1.20; 95% CI 1.04-1.39).

CONCLUSION

Among patients undergoing PCI, the occurrence of peri-procedural MI measured by CK-MB mass assay was ~7%, and more than half of cases were associated with side-branch occlusion. Several higher risk patients, lesions, and procedural characteristics were independent predictors of peri-procedural MI. Peri-procedural MI was associated with an increase in mortality.

Classification of myocardial infarction and unstable angina: a re-assessment

True or impending myocardial injury is being defined as an acute coronary syndrome (ACS), and includes ST-segment elevation MI, non-ST-segment elevation MI, and unstable angina. According to the revised MI definitions, patients with ischemic symptoms but with only a minor rise and fall in any biomarker are now being classified as having true myocardial injury. Against this background, this paper re-examines the position of "unstable angina" within the ACS context. It now must be acknowledged that the most recent definition of unstable angina, from 2000, which divided patients with unstable angina in those who were troponin-positive and those that remained troponin-negative, overlaps with the current MI definition. The seminal 1989 clinical definition of unstable angina thus remains the most appropriate description of that ACS entity. This "paradigm shift" has significant bearing on both the numbers of patients with non-ST-segment elevation MI, as well as on their prognosis. The same is true for patients now being diagnosed as having "unstable angina." To a large extent, future cardiovascular risk is determined by clinical parameters, and their proper assessment thus remains paramount. Elevated age, previous MI, diabetes and/or renal dysfunction and, in particular, the presence of recent onset of symptoms (Braunwald category IIIB) with concomitant ECG changes should identify those at high risk. Patients with such characteristics should benefit from thorough medical management, including extensive platelet inhibition in most and coronary revascularization in many.

A 3-hour diagnostic algorithm for non-ST-elevation myocardial infarction using high-sensitivity cardiac troponin T in unselected older patients presenting to the emergency department

OBJECTIVES

To determine if an algorithm implementing a serial high-sensitive cardiac troponin T (hs-cTnT) measurement at presentation (0 h) and at 3 hours after presentation (3h) is helpful for early diagnosis of non-ST-elevation myocardial infarction (NSTEMI) in older patients.

DESIGN

Prospective observational cohort study.

SETTING

An emergency department (ED) of a city hospital covering a population of approximately 1 million in Germany.

PARTICIPANTS

A total of 332 consecutive unselected patients were recruited, of whom 25 had one or more of the prespecified exclusion criteria and 1 had a missing hs-cTnT at 3h, resulting in a final population of 306 patients.

MEASUREMENTS

In addition to clinical examination, hs-cTnT was measured at 0 h and 3 h. The final diagnosis of NSTEMI was adjudicated by two independent consultants and an algorithm for rule-in and rule-out of NSTEMI was developed using classification and regression tree analysis. All patients were followed-up for cardiovascular outcome within 12 months.

RESULTS

Among 306 patients (mean age 81 ± 6 years), 38 (12%) patients had NSTEMI. Accuracy to diagnose NSTEMI was significantly higher for hs-cTnT measurements at 3 h versus 0 h (area under the receiver operating characteristic curve [AUC] 0.88 vs. 0.82, P = .0038) and for absolute versus relative hs-cTnT delta changes (AUC 0.89 versus 0.69, P < .001). A diagnostic algorithm using hs-cTnT values at presentation and absolute delta changes values ruled-in NSTEMI in 23% and ruled-out NSTEMI in 35% of patients. For patients neither fulfilling the rule-in nor the rule-out criteria, an observational zone was established. Cumulative 1-year survival was 79.4%, 88.5%, and 99.1% in patients classified as rule-in, observational zone, and rule-out, respectively.

CONCLUSION

In older patients, serial hs-cTnT measurements and absolute delta-changes at 3h were valuable for early diagnosis of NSTEMI. An algorithm ruled-in NSTEMI in one quarter of patients with high risk and ruled-out NSTEMI in one-third with low risk.

Implementation of standardized assessment and reporting of myocardial infarction in contemporary randomized controlled trials: a systematic review

Myocardial infarction (MI) is a key endpoint in randomized controlled trials (RCTs), but heterogeneous definitions limit comparisons across RCTs or meta-analyses. The 2000 European Society of Cardiology/American College of Cardiology MI redefinition and the 2007 universal MI definition consensus documents made recommendations to address this issue. In cardiovascular randomized trials, we evaluated the impact of implementation of three key recommendations from these reports-troponin use to define MI; separate reporting of spontaneous and procedure-related MI; and infarct size reporting. We searched ClinicalTrials.gov and MEDLINE databases for cardiovascular RCTs with more than 500 patients in which enrolment began between September 2000 and July 2012 and that listed MI in the primary endpoint. We searched English-language publications with primary results or design papers. Of 3222 studies screened, 96 (3.0%) met our criteria. We extracted enrolment start date, number of patients and MI events, follow-up duration, and coronary revascularization rate. Data extraction quality was assessed by duplicated extractions. Of 96 RCTs, 80 had a primary results publication, comprising 608 091 patients and 43 621 endpoint MIs. Myocardial infarction represented 45.3% (95% confidence interval, 40.2-50.4) of events in the primary composite endpoint. Troponin defined MI in 57% (53/93) of trials with an MI definition available. Of these RCTs, three used troponin only if creatine kinase-MB was unavailable, six used troponin to define peri-procedural MI, seven specified the 99th percentile as the MI decision limit, and three reported spontaneous and procedure-related MI separately. None reported biomarker-based infarct size, but five reported MI as multiples of the assay upper limit of normal. Although MI is a major component of cardiovascular RCT primary endpoints, standardized MI reporting and implementation of consensus document recommendations for MI definition are limited. Developing appropriate strategies for uniform implementation is required.

Update: Innovation in cardiology (II). Telecardiology: past, present and future

Technological advances over the past decades have allowed improved diagnosis and monitoring of patients with acute coronary syndromes as well as patients with advanced heart failure. High-quality digital recordings transmitted wirelessly by cellular telephone networks have augmented the prehospital use of transportable electrocardiogram machines as well as implantable devices for arrhythmia monitoring and therapy. The impact of prehospital electrocardiogram recording and interpretation in patients suspected of acute myocardial infarction should not be underestimated. It enables a more widespread access to rapid reperfusion therapy, thereby reducing treatment delay, morbidity and mortality. Further, continuous electrocardiogram monitoring has improved arrhythmia diagnosis and dynamic ST-segment changes have been shown to provide important prognostic information in patients with acute ST-elevation myocardial infarction. Likewise, remote recording or monitoring of arrhythmias and vital signs seem to improve outcome and reduce the necessity of re-admissions or outpatient contacts in patients with heart failure or arrhythmias. In the future telemonitoring and diagnosis is expected to further impact the way we practice cardiology and provide better care for the patient with cardiovascular disease.

Circulating cathepsin K as a potential novel biomarker of coronary artery disease

BACKGROUND

Cathepsin K (CatK) is one of the most potent mammalian collagenases involved in atherosclerosis-based vascular disease. We investigated whether circulating CatK is associated with the prevalence of coronary artery disease (CAD).

METHODS

Two-hundred fifty-two consecutive subjects were enrolled from among patients who underwent coronary angiography and intravascular ultrasound analyses. One-hundred thirty-two age-matched subjects served as controls. Plasma CatK, intact procollagen type I N-terminal propeptide (I-PINP), and linked carboxy-terminal telopeptide of collagen type I (ICTP) were measured.

RESULTS

Patients with CAD had higher CatK levels (44.0 ± 31.2 versus 15.5 ± 8.3 ng/mL, P < 0.001) and ICTP/I-PINP ratios (0.2 ± 0.1 versus 0.04 ± 0.03, P < 0.001) than the controls. Patients with acute coronary syndrome had higher CatK levels than those with stable angina pectoris. Overall, linear regression analysis showed that the CatK levels correlated positively with ICTP/I-PINP ratios (r = 0.41, P < 0.001). Multiple logistic regression analysis showed that CatK levels were independent predictors of CAD (odds ratio, 1.15; 95% CI, 1.07 to 1.23; P < 0.01). Furthermore, CatK levels were also correlated positively with percent plaque volumes and inversely with percent fibrous volumes by intravascular ultrasound.

CONCLUSIONS

These data indicated that high levels of CatK are closely linked with the presence of CAD and that CatK serves as a novel biomarker for CAD.

The Year in Cardiology 2012: acute coronary syndromes

Patients presenting with acute coronary syndromes (ACS) remain amongst the highest-risk of all acute medical admissions. Despite significant reductions in morbidity and mortality via refinements in treatment methods in recent years, such individuals remain at a high risk of recurrent ischaemic events and death. Whilst 2012 has brought a wealth of novel data in the field of ACS regarding diagnosis and both medical and invasive management strategies, continued focus on this high-risk patient subset is necessary to further our understanding and improve patient outcomes.

Circulating Cell and Plasma microRNA Profiles Differ between Non-ST-Segment and ST-Segment-Elevation Myocardial Infarction

BACKGROUND

Differences in plasma and whole blood expression microRNAs (miRNAs) in patients with an acute coronary syndrome (ACS) have been determined in both in vitro and in vivo studies. Although most circulating miRNAs are located in the cellular components of whole blood, little is known about the miRNA profiles of whole blood subcomponents, including plasma, platelets and leukocytes in patients with myocardial ischemia.

METHODS

Thirteen patients with a ST-segment-elevation (STEMI) or non-ST-segment elevation (NSTEMI) myocardial infarction were identified in the University of Massachusetts Medical Center Emergency Department (ED) or cardiac catheterization laboratory between February and June of 2012. Whole blood was obtained from arterial blood samples at the time of cardiac catheterization and cell-specific miRNA profiling was performed. Expression of 343 miRNAs was quantified from whole blood, plasma, platelets, and peripheral blood mononuclear cells using a high-throughput, quantitative Real-Time polymerase-chain reaction system (qRT-PCR).

RESULTS

MiRNAs associated with STEMI as compared to NSTEMI patients included miR-25-3p, miR-221-3p, and miR-374b-5p. MiRNA 30d-5p was associated with plasma, platelets, and leukocytes in both STEMI and NSTEMI patients; miRNAs 221-3p and 483-5p were correlated with plasma and platelets only in NSTEMI patients.

CONCLUSIONS

Cell-specific miRNA profiles differed between patients with STEMI and NSTEMI. The miRNA distribution is also unique amongst plasma, platelets, and leukocytes in patients with ischemic heart disease or ACS. Our findings suggest unique miRNA profiles among the circulating subcomponents in patients presenting with myocardial ischemia.

The distribution of cardiac troponin I in a population of healthy children: lessons for adults

OBJECTIVES

To describe the distribution of hs-cTnI in a large cohort of healthy children.

DESIGN AND METHODS

As part of the LOOK study, blood was collected from a large cohort of healthy children on 3 separate occasions when the children were aged 8, 10 and 12years. Samples were stored at -80°C after collection and assayed after 1 freeze-thaw cycle using a pre-commercial release hs-cTnI assay from Abbott Diagnostics.

RESULTS

More than 98% of the 12year-old children had cTnI above the LoD of 1.0ng/L. For the 212 boys the central 95% of results was distributed in a Gaussian fashion. For the 237 girls, the initial analysis was non-Gaussian, but after the elimination of 2 results, the pattern for girls was also Gaussian.

CONCLUSIONS

In healthy children, cTnI is present in a Gaussian distribution. Even minor illnesses can cause some troponin release, distorting this Gaussian distribution.

High Sensitivity Troponins — Translating Research into Practice

Troponin is vital in the evaluation of acute coronary syndrome. Decision limits, based on the 99th percentile upper reference limit derived from a sufficiently large normal reference population, must be determined for each specific troponin method. The new troponins exhibit high-sensitivity performance – assay precision at less than 10% coefficient of variation (at the 99th percentile upper reference limit) and ability to detect measurable values in healthy subjects. The troponin literature has reached a tipping point necessitating guidance on its use from specialist societies.

Activity of MMP-19 inhibits capillary-like formation due to processing of nidogen-1

Matrix metalloproteinase 19 (MMP-19) is able to process various proteins of the basement membrane. To investigate the impact of MMP-19 activity on endothelial cells in the context of tumor extracellular matrix (ECM), we treated Matrigel matrix with an active recombinant MMP-19 and analyzed its effect on capillary-like formation. Human microvascular endothelial cells (HMEC-1) could not form capillary-like formation on Matrigel treated with recombinant MMP-19. Analyzing the Matrigel proteins, we found that MMP-19 preferentially cleaved nidogen-1. The cleavage site of nidogen-1 was mapped to Thr867-Leu868. This cleavage separates the G3 globular domain containing the binding site for the gamma1 chain of laminin-1 and collagen IV and thus abolishes the capacity of nidogen-1 to cross-link ECM proteins. Anti-nidogen antibodies directed against the G3 domain of nidogen-1 inhibited the capillary-like structure formation to a similar extent as MMP-19. Since nidogen-1 is thought to stabilize microvessels, MMP-19 might be one of the enzymes that interferes with stabilization or maturation of nascent vasculature.