High-sensitivity troponin in chronic kidney disease: Considerations in myocardial infarction and beyond.

Acute myocardial infarction (MI) represents one of the most common hospital encounters, with significant short-term and long-term morbidity and mortality, and frequently occurs in patients with chronic kidney disease (CKD). Cardiac troponin is an exquisitely sensitive biomarker for myocardial injury and plays an essential role in the diagnosis, risk-stratification, and management of MI. In 2017, the United States Food and Drug Administration approved Roche Diagnostics' 5th generation high-sensitivity cardiac troponin (hs-cTn) for clinical use. Whilst the improved analytical sensitivity of these new high-sensitivity troponin assays facilitate early diagnosis of MI, it also frequently identifies troponin elevations above the conventional reference threshold in the context of non-coronary conditions such as renal dysfunction, and can represent a major diagnostic challenge to clinicians. Furthermore, the optimal management strategy of patients with troponin elevation and high comorbidity burden, a common issue in patients with CKD, remains undefined. In recent years, there has been substantial research and progress undertaken in this rapidly evolving area. In this review, we aim to provide clinicians with an overview of hs-cTn in the setting of CKD as well as an update on its application and the particular considerations involved in the management of myocardial infarction, stable coronary artery disease and myocardial injury in this high risk population.

The appropriateness of coronary investigation in myocardial injury and type 2 myocardial infarction (ACT-2): A randomized trial design.

BACKGROUND: Elevated troponin level findings among patients presenting with suspected acute coronary syndrome (ACS) or another intercurrent illness undeniably identifies patients at increased risk of mortality. Whilst enhancing our capacity to discriminate risk, the use of high-sensitivity troponin assays frequently identifies patients with myocardial injury (i.e. troponin rise without acute signs of myocardial ischemia) or type 2 myocardial infarction (T2MI; oxygen supply-demand imbalance). This leads to the clinically challenging task of distinguishing type 1 myocardial infarction (T1MI; coronary plaque rupture) from myocardial injury and T2MI in the context of concurrent acute illness. Diagnostic discernment in this context is crucial because MI classification has implications for further investigation and care. Early invasive management is of well-established benefit among patients with T1MI. However, the appropriateness of this investigation in the heterogeneous context of T2MI, where there is high competing mortality risk, remains unknown. Although coronary angiography in T2MI is advocated by some, there is insufficient evidence in existing literature to support this opinion as highlighted by current national guidelines. OBJECTIVE: The objective is to evaluate the clinical and economic impact of early invasive management with coronary angiography in T2MI in terms of all-cause mortality and cost effectiveness. DESIGN: This prospective, pragmatic, multicenter, randomized trial among patients with suspected supply demand ischemia leading to troponin elevation (n=1,800; T2MI [1,500], chronic myocardial injury [300]) compares the impact of invasive angiography (or computed tomography angiography as per local preference) within 5 days of randomization versus conservative management (with or without functional testing at clinician discretion) on all-cause mortality by 2 years. Randomized treatment allocation will be stratified by baseline estimated risk of mortality using the Acute Physiology, Age, and Chronic Health Evaluation (APACHE) III risk score. Cost-effectiveness will be evaluated by follow-up on clinical events, quality of life, and resource utilization over 24 months. SUMMARY: Ascertaining the most appropriate first-line investigative strategy for these commonly encountered high-risk T2MI patients in a randomized comparative study will be pivotal in informing evidence-based guidelines that lead to better patient and health care outcomes.

Transcatheter Tricuspid Valve Replacement With the EVOQUE System: 1-Year Outcomes of a Multicenter, First-in-Human Experience.

OBJECTIVES: The aim of this study was to report the midterm outcomes at 1 year in the expanded first-in-human experience with the transfemoral EVOQUE system (Edwards Lifesciences) for tricuspid regurgitation (TR). BACKGROUND: Untreated TR is associated with excess mortality and morbidity. The first-in-human experience with the EVOQUE tricuspid valve replacement system reported favorable 30-day outcomes with no mortality in a compassionate use population. METHODS: Twenty-seven patients with severe TR were treated with the EVOQUE system in a compassionate use experience at 7 centers between May 2019 and July 2020. All patients had clinical right-sided heart failure (HF) and were deemed inoperable and unsuitable for transcatheter edge-to-edge repair by the institutional heart teams. The clinical outcomes collected included all-cause mortality, symptom status, TR severity, HF hospitalization, and major adverse cardiovascular events. RESULTS: At baseline, all patients (age: 77 ± 8 years, 89% female) were at high surgical risk (mean Society of Thoracic Surgeons score: 8.6% ± 5.5%), with 89% New York Heart Association functional class III/IV. TR was predominantly functional in etiology (19/27, 70%). At 1 year, mortality was 7% (2/27), 70% of patients were New York Heart Association functional class I/II, and 96% and 87% of patients had a TR grade ≤2+ and ≤1+, respectively. Between 30 days and 1 year, 2 patients experienced HF hospitalizations, and 1 patient required a new pacemaker implantation. CONCLUSIONS: In this early, compassionate use experience, the transfemoral transcatheter EVOQUE tricuspid valve replacement system demonstrated durable efficacy, persistent improvement in symptom status, and low rates of mortality and HF hospitalizations at a 1-year follow-up. Further studies are underway to validate its efficacy.

Troponin elevation pattern and subsequent cardiac and non-cardiac outcomes: Implementing the Fourth Universal Definition of Myocardial Infarction and high-sensitivity troponin at a population level.

BACKGROUND: The Fourth Universal Definition of Myocardial Infarction (MI) differentiates MI from myocardial injury. We characterised the temporal course of cardiac and non-cardiac outcomes associated with MI, acute and chronic myocardial injury. METHODS: We included all patients presenting to public emergency departments in South Australia between June 2011-Sept 2019. Episodes of care (EOCs) were classified into 5 groups based on high-sensitivity troponin-T (hs-cTnT) and diagnostic codes: 1) Acute MI [rise/fall in hs-cTnT and primary diagnosis of acute coronary syndrome], 2) Acute myocardial injury with coronary artery disease (CAD) [rise/fall in hs-cTnT and diagnosis of CAD], 3) Acute myocardial injury without CAD [rise/fall in hs-cTnT without diagnosis of CAD], 4) Chronic myocardial injury [elevated hs-cTnT without rise/fall], and 5) No myocardial injury. Multivariable flexible parametric models were used to characterize the temporal hazard of death, MI, heart failure (HF), and ventricular arrhythmia. RESULTS: 372,310 EOCs (218,878 individuals) were included: acute MI (19,052 [5.12%]), acute myocardial injury with CAD (6,928 [1.86%]), acute myocardial injury without CAD (32,231 [8.66%]), chronic myocardial injury (55,056 [14.79%]), and no myocardial injury (259,043 [69.58%]). We observed an early hazard of MI and HF after acute MI and acute myocardial injury with CAD. In contrast, subsequent MI risk was lower and more constant in patients with acute injury without CAD or chronic injury. All patterns of myocardial injury were associated with significantly higher risk of all-cause mortality and ventricular arrhythmia. CONCLUSIONS: Different patterns of myocardial injury were associated with divergent profiles of subsequent cardiac and non-cardiac risk. The therapeutic approach and modifiability of such excess risks require further research.

Multidisciplinary transcatheter aortic valve replacement heart team programme improves mortality in aortic stenosis.

Objectives: To analyse the effect of the implementation of a transcatheter aortic valve replacement (TAVR) and multidisciplinary heart team programme on mortality in severe aortic stenosis (AS). Methods: A retrospective, observational cohort study was performed using the echocardiography, cardiothoracic surgery and TAVR databases between 1 January 2006 and 31 December 2016. Outcomes were compared between the pre- and post-TAVR programme eras in a tertiary referral centre providing transcatheter and surgical interventions for AS.All-cause mortality within 5 years from diagnosis was determined for 3399 patients with echocardiographically defined severe AS. Results: Of 3399 patients, there were 210 deaths (6.2%) at 30 days and 1614 deaths (47.5%) at 5 years.Overall, patients diagnosed in the post-TAVR programme era were older, with a lower ejection fraction and more severe AS, but were less comorbid.Among 705 patients undergoing intervention, those in the post-TAVR programme era were older, with a lower ejection fraction and more severe AS but no significant differences in comorbidities.Using an inverse probability weighted cohort and a Cox proportional hazards model, a significant mortality benefit was noted between eras alone (HR=0.86, 95% CI 0.77 to 0.97, p=0.015). When matching for age, comorbidities and valve severity, this benefit was more evident (HR=0.82, 95% CI 0.73 to 0.92, p=0.001).After adjusting for the presence of aortic valve intervention, a significant benefit persisted (HR=0.84, 95% CI 0.75 to 0.95, p=0.005). Conclusion: The implementation of a TAVR programme is associated with a mortality benefit in the population with severe AS, independent of the expansion of access to intervention.

Invasive management of acute coronary syndrome: Interaction with competing risks.

BACKGROUND: The aim of this study was to characterise the interaction between ACS- and non-ACS-risk on the benefits of invasive management in patients presenting with acute coronary syndrome (ACS). METHODS: Consecutive patients admitted to a tertiary hospital's Cardiac Care Unit in the months of July-December, 2003-2011 with troponin elevation (>30 ng/L) were included. "ACS-specific-risk" was estimated using the GRACE score and "non-ACS-risk" was estimated using the Charlson-Comorbidity-Index (CCI). Inverse-probability-of-treatment weighting was used to adjust for baseline differences between patients who did or did not receive invasive management. A multivariable flexible parametric model was used to characterise the time-varying hazard. RESULTS: In total, 3057 patients were included with a median follow-up of 9.0 years. Based on CCI, 1783 patients were classified as 'low-non-ACS risk' (CCI ≤ 1; invasive management 81%; 12-month mortality 5%), 820 as 'medium-non-ACS risk' (CCI 2-3; invasive management 68%; 12-month mortality 13%), and 468 as 'high-non-ACS risk' (CCI ≥ 4; invasive management 47%; 12-month mortality 29%). After adjustment, invasive management was associated with a significant reduction in one-year overall-mortality in the 'low-risk' and 'medium-risk' groups (HR = 0.38, 95%CI:0.26-0.56; HR = 0.46, 95%CI:0.32-0.67); but not in the 'high-risk' group (HR = 1.02, 95%CI:0.67-1.56). The absolute benefit of invasive management was greatest with higher baseline ACS-risk, with a non-linear interaction between ACS- and non-ACS-risk. CONCLUSIONS: There is a complex interaction between ACS- and non-ACS-risk on the benefit of invasive management. These results highlight the need to develop robust methods to objectively quantify risk attributable to non-ACS comorbidities in order to make informed decisions regarding the use of invasive management in individuals with numerous comorbidities.