High-Sensitivity Troponin I after Cardiac Surgery and 30-Day Mortality.

BACKGROUND: Consensus recommendations regarding the threshold levels of cardiac troponin elevations for the definition of perioperative myocardial infarction and clinically important periprocedural myocardial injury in patients undergoing cardiac surgery range widely (from >10 times to ≥70 times the upper reference limit for the assay). Limited evidence is available to support these recommendations. METHODS: We undertook an international prospective cohort study involving patients 18 years of age or older who underwent cardiac surgery. High-sensitivity cardiac troponin I measurements (upper reference limit, 26 ng per liter) were obtained 3 to 12 hours after surgery and on days 1, 2, and 3 after surgery. We performed Cox analyses using a regression spline that explored the relationship between peak troponin measurements and 30-day mortality, adjusting for scores on the European System for Cardiac Operative Risk Evaluation II (which estimates the risk of death after cardiac surgery on the basis of 18 variables, including age and sex). RESULTS: Of 13,862 patients included in the study, 296 (2.1%) died within 30 days after surgery. Among patients who underwent isolated coronary-artery bypass grafting or aortic-valve replacement or repair, the threshold troponin level, measured within 1 day after surgery, that was associated with an adjusted hazard ratio of more than 1.00 for death within 30 days was 5670 ng per liter (95% confidence interval [CI], 1045 to 8260), a level 218 times the upper reference limit. Among patients who underwent other cardiac surgery, the corresponding threshold troponin level was 12,981 ng per liter (95% CI, 2673 to 16,591), a level 499 times the upper reference limit. CONCLUSIONS: The levels of high-sensitivity troponin I after cardiac surgery that were associated with an increased risk of death within 30 days were substantially higher than levels currently recommended to define clinically important periprocedural myocardial injury. (Funded by the Canadian Institutes of Health Research and others; VISION Cardiac Surgery ClinicalTrials.gov number, NCT01842568.).

Universal MI definition update for cardiovascular disease.

The new third universal definition of myocardial infarction (MI) is based on troponin elevation together with ischemic symptoms, ischemic ECG changes, and imaging evidence. MIs are classified into five types as to whether they are spontaneous, secondary to imbalance between coronary artery blood supply and demand, related to sudden death, or related to revascularization procedures. The definition is based on a rise and/or fall in troponin levels occurring in a clinical setting. There have been modifications over previous definitions with adding intracoronary thrombus as a criterion, adding a new type of MI type 4c, and raising the cutpoint for the diagnosis of MI related to percutaneous coronary intervention to five times the 99(th) percentile upper reference limit and requiring evidence of ischemia or angiographic complications. In clinical practice, trials, and registries, different definitions are used. There is a need for consistency with regard to the definition of MI and the universal definition should be implemented.

Human Stem Cells in Regenerative Medicine.

Modern medicine now has the capacity to improve therapy for many human diseases by introducing adult somatic stem cells that can repair or replace defective or damaged tissues. However, the area is still in an early phase of development, so all new applications must be carefully designed for maximal safety as well as effectiveness.

Type 2 Myocardial Infarction and Long-Term Mortality Risk Factors: A Retrospective Cohort Study.

INTRODUCTION: In-hospital risk factors for type 1 myocardial infarction (MI) have been extensively investigated, but risk factors for type 2 MI are still emerging. Moreover, type 2 MI remains an underdiagnosed and under-researched condition. Our aim was to assess survival rates after type 2 MI and to analyze the risk factors for patient prognosis after hospitalization. METHODS: We conducted a retrospective database analysis of patients with MI diagnosis who were treated in Vilnius University Hospital Santaros Klinikos. A total of 6495 patients with the diagnosis of MI were screened. The primary study endpoint was long-term all-cause mortality. The predictive value of laboratory tests was estimated including blood hemoglobin, D dimer, creatinine, brain natriuretic peptide (BNP), C-reactive protein (CRP), and troponin levels. RESULTS: Out of all the patients diagnosed with MI there were 129 cases of type 2 MI (1.98%). Death rate almost doubled from 19.4% at 6 months to 36.4% after 2 years of follow-up. Higher age and impaired kidney function were risk factors for death both during hospitalization and after 2 years of follow-up. Lower hemoglobin (116.6 vs. 98.9 g/L), higher creatinine (90 vs. 161.9 µmol/L), higher CRP (31.4 vs. 63.3 mg/l), BNP (707.9 vs. 2999.3 ng/L), and lower left ventricle ejection fraction were all predictors of worse survival after 2 years of follow-up. Preventive medication during hospitalization can decrease the mortality risk: angiotensin-converting enzyme inhibitor (ACEi) (HR 0.485, 95% CI 0.286-0.820) and statins (HR 0.549, 95% CI 0.335-0.900). No significant influence was found for beta blockers (HR 0.662, 95% CI 0.371-1.181) or aspirin (HR 0.901, 95% CI 0.527-1.539). CONCLUSIONS: There is significant underdiagnosis of type 2 MI (1.98% out of all MIs). If the patient is prescribed a preventive medication like ACEi or statins, the mortality risk is lower. Increased awareness of elevation of laboratory results could help to improve the treatment of these patients and identify the most vulnerable groups.

Type 1, Type 2 Myocardial Infarction and Non-Ischemic Myocardial Injury-Opinion from the Front Lines.

Differentiating patients with type 1 and type 2 myocardial infarction (MI) and acute non-ischemic myocardial injury continues to be a problem for many clinicians. Type 1 MI is the most easily defined. It involves the rise and fall of blood troponin measurements (only falling values if the patient arrives late) with an appropriate clinical observation consistent with myocardial ischemia. Diagnosis and therapy of type 1 MI are well understood and usually present no problem to the physician. The clinical scenarios leading to type 2 MI and non-ischemic myocardial injury are, however, often fraught with greater degrees of uncertainty. In addition, therapy for these latter 2 entities is poorly defined. This review will present 3 patient scenarios that should help clinicians understand the difference between these 3 entities as well as possible therapeutic interventions.

Randomized Pilot Trial on Optimal Treatment Strategy, Myocardial Changes, and Prognosis of Patients with Myocardial Infarction with Nonobstructive Coronary Arteries (MINOCA).

BACKGROUND: Myocardial infarction with nonobstructive coronary arteries (MINOCA) remains an unresolved challenge. Many different diagnostic approaches are often required to diagnose, confirm, and evaluate MINOCA. The prevalence can be as high as 13% of all acute myocardial infarction patients, indicating that this condition is not rare. At this time, there have been no completed randomized clinical trials involving MINOCA patients, and a better understanding of the mechanisms and management of these patients is important. This exploratory analysis seeks to find possible etiologic factors, the value of novel biomarkers, and the effect of different treatment strategies in patients with MINOCA. METHODS: This prospective randomized pilot trial will include 150 patients with MINOCA. A thorough clinical, laboratory, and imaging evaluation will be performed, including novel biomarkers and modern imaging techniques (heart magnetic resonance imaging and noninvasive testing). The duration of the enrollment is 18 months, and duration of the follow-up is 12 months from the enrollment of the first patient. RESULTS: The trial is registered under www.clinicaltrials.gov: NCT04538924. The study is currently recruiting participants. CONCLUSIONS: Because MINOCA is not a benign disease, the results of the current investigation could inform future diagnostic and therapeutic strategies and enhance the understanding of MINOCA patients.

Recommendations for the use of cardiac troponin measurement in acute cardiac care.

The release of cardiomyocyte components, i.e. biomarkers, into the bloodstream in higher than usual quantities indicates an ongoing pathological process. Thus, detection of elevated concentrations of cardiac biomarkers in blood is a sign of cardiac injury which could be due to supply-demand imbalance, toxic effects, or haemodynamic stress. It is up to the clinician to determine the most probable aetiology, the proper therapeutic measures, and the subsequent risk implied by the process. For this reason, the measurement of biomarkers always must be applied in relation to the clinical context and never in isolation. There are a large number of cardiac biomarkers, but they can be subdivided into four broad categories, those related to necrosis, inflammation, haemodynamic stress, and/or thrombosis. Their usefulness is dependent on the accuracy and reproducibility of the measurements, the discriminatory limits separating pathology from physiology, and their sensitivity and specificity for specific organ damage and/or disease processes. In recent years, cardiac biomarkers have become important adjuncts to the delivery of acute cardiac care. Therefore, the Working Group on Acute Cardiac Care of the European Society of Cardiology established a committee to deal with ongoing and newly developing issues related to cardiac biomarkers. The intention of the group is to outline the principles for the application of various biomarkers by clinicians in the setting of acute cardiac care in a series of expert consensus documents. The first of these will focus on cardiac troponin, a pivotal marker of cardiac injury/necrosis.

N-Acetylcysteine for Cardiac Protection During Coronary Artery Reperfusion: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Coronary artery reperfusion is essential for the management of symptoms in the patients with myocardial ischemia. However, the benefit of reperfusion often comes at an expense of paradoxical injury, which contributes to the adverse events, and sometimes heart failure. Reperfusion is known to increase the production of reactive oxygen species (ROS). We address whether N-acetylcysteine (NAC) reduces the ROS and alleviates reperfusion injury by improving the clinical outcomes. A literature search for the randomized controlled trials (RCTs) was carried out in the five biomedical databases for testing the effects of NAC in patients undergoing coronary artery reperfusion by percutaneous coronary intervention, thrombolysis, or coronary artery bypass graft. Of 787 publications reviewed, 28 RCTs were identified, with a summary of 2,174 patients. A meta-analysis using the random effects model indicated that NAC administration during or prior to the reperfusion procedures resulted in a trend toward a reduction in the level of serum cardiac troponin (cTn) [95% CI, standardized mean difference (SMD) -0.80 (-1.75; 0.15), p = 0.088, n = 262 for control, 277 for NAC group], and in the incidence of postoperative atrial fibrillation [95% CI, relative risk (RR) 0.57 (0.30; 1.06), p = 0.071, n = 484 for control, 490 for NAC group]. The left ventricular ejection fraction or the measures of length of stay in intensive care unit (ICU) or in hospital displayed a positive trend that was not statistically significant. Among the nine trials that measured ROS, seven showed a correlation between the reduction of lipid peroxidation and improved clinical outcomes. These lines of evidence support the potential benefit of NAC as an adjuvant therapy for cardiac protection against reperfusion injury.

Six Months of Inspiratory Muscle Training to Lower Blood Pressure and Improve Endothelial Function in Middle-Aged and Older Adults With Above-Normal Blood Pressure and Obstructive Sleep Apnea: Protocol for the CHART Clinical Trial.

Background: Cardiovascular disease is a major global health concern and prevalence is high in adults with obstructive sleep apnea (OSA). Lowering blood pressure (BP) can greatly reduce cardiovascular disease risk and physical activity is routinely prescribed to achieve this goal. Unfortunately, many adults with OSA suffer from fatigue, daytime sleepiness, and exercise intolerance-due to poor sleep quality and nocturnal hypoxemia-and have difficulty initiating and maintaining an exercise program. High-resistance inspiratory muscle strength training (IMST) is a simple, time-efficient breathing exercise consistently reported to reduce BP in small, selective groups of both healthy and at-risk adults. Herein we present the study protocol for a randomized clinical trial to determine the long-term efficacy of IMST performed regularly for 24 weeks in middle-aged and older adults with OSA. The primary outcome is casual systolic BP. Secondary outcomes are 24-h systolic BP and circulating plasma norepinephrine concentration. Other outcomes include vascular endothelial function (endothelial-dependent and -independent dilation), aortic stiffness, casual and 24-h diastolic BP, and the influence of circulating factors on endothelial cell nitric oxide and reactive oxygen species production. Overall, this trial will establish efficacy of high-resistance IMST for lowering BP and improving cardiovascular health in middle-aged and older adults with OSA. Methods: This is a single-site, double-blind, randomized clinical trial. A minimum of 92 and maximum of 122 male and female adults aged 50-80 years with OSA and above-normal BP will be enrolled. After completion of baseline assessments, subjects will be randomized in a 1:1 ratio to participate in either high-resistance or sham (low-resistance) control IMST, performed at home, 5 min/day, 5 days/week, for 24 weeks. Repeat assessments will be taken after the 24-week intervention, and after 4 and 12 weeks of free living. Discussion: This study is designed to assess the effects of 24 weeks of IMST on BP and vascular function. The results will characterize the extent to which IMST can reduce BP when performed over longer periods (i.e., 6 months) than have been assessed previously. Additionally, this study will help to determine underlying mechanisms driving IMST-induced BP reductions that have been reported previously. Clinical Trial Registration: This trial is registered with ClinicalTrials.gov (Registration Number: NCT04932447; Date of registration June 21, 2021).

Safety of Outpatient Milrinone Infusion in End-Stage Heart Failure: ICD-Level Data on Atrial Fibrillation and Ventricular Tachyarrhythmias.

BACKGROUND: Milrinone infusion is one of a few select "non-device" therapies for patients with New York Heart Association (NYHA) class IV, stage D heart failure, which has been associated with an increase in ventricular tachyarrhythmia and atrial fibrillation. Milrinone improves hemodynamics and provides symptomatic relief. Many patients with end-stage heart failure die from cardiac pump failure, and the impact of ventricular tachyarrhythmia and atrial fibrillation on their mortality is unclear. METHODS: This is a retrospective study of 98 consecutive patients receiving outpatient milrinone in a single center from 2008 to 2016. The primary endpoint of the study was overall survival on milrinone. Secondary endpoints were incidence of post-milrinone implantable cardioverter defibrillator (ICD) shocks and development of ventricular tachyarrhythmia or atrial fibrillation. RESULTS: Median survival was 581 ± 96 days with no difference between those with prior ventricular tachyarrhythmia and those without at 1 month (92% vs 97%, P = 0.34), 6 months (67% vs 73%, P = 0.75), and 12 months (67% vs 61%, P = 0.88). Seven out of 12 (58%) patients with prior ventricular tachyarrhythmia had ICD shocks, as compared to 5 out of 78 (6.4%) (P <0.001). Thirty-five patients had atrial fibrillation prior to starting milrinone, which decreased to 72% (P <0.05) by the third follow-up time period (7-9 months). Amiodarone use was protective against new onset atrial fibrillation. CONCLUSIONS: Patients with stage D heart failure with a history of ventricular tachyarrhythmia have similar survival on outpatient milrinone compared to those without. However, those with prior ventricular tachyarrhythmia received more ICD shocks for more ventricular tachyarrhythmias. Milrinone remains a viable therapy for patients with stage D heart failure with limited therapeutic options.