Role of Antitroponin Antibodies and Macrotroponin in the Clinical Interpretation of Cardiac Troponin.

Cardiac troponin is extensively used as a biomarker in modern medicine due to its diagnostic capability for myocardial injury, as well as its predictive and prognostic value for cardiac diseases. However, heterophile antibodies, antitroponin antibodies, and macrotroponin complexes can be observed both in seemingly healthy individuals and patients with cardiac diseases, potentially leading to false positive or disproportionate elevation of cTn (cardiac troponin) assay results and introducing discrepancies in clinical interpretations with impact on medical management. In this review article, we describe the possible mechanisms of cTn release and the sources of variations in the assessment of circulating cTn levels. We also explore the pathophysiological mechanisms underlying antitroponin antibody development and discuss the influence exerted by macrotroponin complexes on the results of immunoassays. Additionally, we explore approaches to detect these complexes by presenting various clinical scenarios encountered in routine clinical practice. Finally, unsolved questions about the development, prevalence, and clinical significance of cardiac autoantibodies are discussed.

Optimizing screening and management of cardiovascular health in prostate cancer: A review.

In clinical practice, cancer management does not consistently encompass screening and identification of cardiovascular (CV) risk. The use of androgen deprivation therapy (ADT) in prostate cancer has been associated with increased CV risk and development of metabolic syndrome, necessitating identification of patients at risk in this population (e.g., those with pre-existing CV disease). A multidisciplinary team of Canadian physicians was assembled to develop a series of recommendations intended to identify patients who may benefit from optimal management of their CV disease and/or modification of cardiac risk factors. A key goal was the development of a simple screening tool for identification of patients with pre-existing CV disease. This simple and inclusive set of recommendations are intended for use within urology clinics to facilitate holistic approaches and simplify the management of patients.

Single Versus Standard Multiview Assessment of Global Longitudinal Strain for the Diagnosis of Cardiotoxicity During Cancer Therapy.

OBJECTIVES: The goal of this study was to compare echocardiographic measurements of global longitudinal strain (GLS) (using 3 apical views) with single-view longitudinal strain (LS, 4- or 2-chamber [4CV_LS and 2CV_LS, respectively]) for detection of cancer-therapy related cardiotoxicity. BACKGROUND: GLS is useful for the detection of cardiotoxicity, but the need for repeated measurements poses a significant burden on busy echocardiography laboratories. A single-view LS measurement, possibly at point of care, could improve efficiency. METHODS: Seventeen international centers prospectively recruited 108 patients (mean age 54 ± 13 years) at high risk for cardiotoxicity as part of the ongoing SUCCOUR (Strain Surveillance for Improving Cardiovascular Outcomes During Chemotherapy) randomized controlled trial. Echocardiography performed at baseline and follow-up were analyzed in a core laboratory setting blinded to clinical information. Peak systolic GLS and LS were measured from raw data. Cardiotoxicity was defined by reduction in left ventricular ejection fraction >0.10 to <0.55 or a relative drop in GLS by ≥12%. RESULTS: Cardiotoxicity developed in 46 patients by either criteria. Baseline and follow-up 2-dimensional left ventricular ejection fraction were 61 ± 4% and 58 ± 5%, respectively (p < 0.001). The baseline GLS (-20.9 ± 2.4%) was not different from 4CV_LS (-20.7 ± 2.5%; p = 0.09) or 2CV_LS (-21.1 ± 3.1%; p = 0.25). The follow-up GLS (-19.5 ± 2.4%) was also similar to 4CV_LS (-19.5 ± 2.6%; p = 0.80) and 2CV_LS (-19.7 ± 3.1%; p = 0.19). There was good correlation between GLS and 4CV_LS at baseline (r = 0.86; p < 0.001) and follow-up (r = 0.89; p < 0.001) and with 2CV_LS at baseline (r = 0.87; p < 0.001) and follow-up (r = 0.88; p < 0.001). However, there was 15% to 22% disagreement between GLS and 4CV_LS or 2CV_LS for the detection of cardiotoxicity. The interobserver and intraobserver reproducibility was higher for GLS (intraclass correlation: 0.93 to 0.95; coefficient of variance: 2.9% to 3.7%) compared with either single-chamber-based LS measurement (intraclass correlation: 0.85 to 0.91; coefficient of variance: 4.1% to 4.8%). CONCLUSIONS: Although there was good correlation between GLS and single-view LS measurements, single-view LS measurement led to disagreement in the diagnosis of cardiotoxicity in up to 22% of patients. GLS measurements were more reproducible than single-view LS. GLS based on 3 apical views should remain the preferred technique for detection of cardiotoxicity. (Strain Surveillance for Improving Cardiovascular Outcomes During Chemotherapy [SUCCOUR]; ACTRN12614000341628).

Evaluation of human epidermal growth factor receptor 2 (HER2) single nucleotide polymorphisms (SNPs) in normal and breast tumor tissues and their link with breast cancer prognostic factors.

Amplification of the human epidermal growth factor receptor 2 (HER2) gene is associated with worse prognosis and decreased overall survival in breast cancer patients. The HER2 gene contains several polymorphisms; two of the best-characterized HER2 polymorphisms are Ile655Val and Ala1170Pro. The aim of this study was to evaluate the association between these two HER2 polymorphisms in normal breast and breast cancer tissues and known breast cancer prognostic factors in a retrospective cohort study of 73 women with non-metastatic HER2-positive breast cancer. HER2 polymorphisms were assessed in breast cancer tissue and normal breast tissue using TaqMan assay. Ala1170Pro polymorphism in normal breast tissue was associated with age at diagnosis (p = 0.007), tumor size (p = 0.004) and lymphovascular invasion (p = 0.06). Similar significant associations in cancer tissues were observed. No association between the Ile655Val polymorphism and prognostic factors were observed. However, we found significant differences in the distribution of Ile655Val (p = 0.03) and Ala1170Pro (p = 0.01) genotypes between normal breast and breast tumor tissues. This study demonstrates that only the Ala1170Pro polymorphism is associated with prognostic factors in HER2-positive breast cancer patients. Moreover, our results suggest that both HER2 polymorphisms could play a significant role in carcinogenesis in non-metastatic HER2-positive breast cancer women.

Canadian Cardiovascular Society Guidelines for Evaluation and Management of Cardiovascular Complications of Cancer Therapy.

Modern treatment strategies have led to improvements in cancer survival, however, these gains might be offset by the potential negative effect of cancer therapy on cardiovascular health. Cardiotoxicity is now recognized as a leading cause of long-term morbidity and mortality among cancer survivors. This guideline, authored by a pan-Canadian expert group of health care providers and commissioned by the Canadian Cardiovascular Society, is intended to guide the care of cancer patients with established cardiovascular disease or those at risk of experiencing toxicities related to cancer treatment. It includes recommendations and important management considerations with a focus on 4 main areas: identification of the high-risk population for cardiotoxicity, detection and prevention of cardiotoxicity, treatment of cardiotoxicity, and a multidisciplinary approach to cardio-oncology. All recommendations align with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. Key recommendations for which the panel provides a strong level of evidence include: (1) that routine evaluation of traditional cardiovascular risk factors and optimal treatment of preexisting cardiovascular disease be performed in all patients before, during, and after receiving cancer therapy; (2) that initiation, maintenance, and/or augmentation of antihypertensive therapy be instituted per the Canadian Hypertension Educational Program guidelines for patients with preexisting hypertension or for those who experience hypertension related to cancer therapy; and (3) that investigation and management follow current Canadian Cardiovascular Society heart failure guidelines for cancer patients who develop clinical heart failure or an asymptomatic decline in left ventricular ejection fraction during or after cancer treatment. This guideline provides guidance to clinicians on contemporary best practices for the cardiovascular care of cancer patients.

Alcohol and HER2 polymorphisms as risk factor for cardiotoxicity in breast cancer treated with trastuzumab.

BACKGROUND: Trastuzumab has no major side-effects except the potential for cardiac toxicity. The main objective of this study was to evaluate the association between trastuzumab-associated cardiac toxicity and two potential risk factors: alcohol intake and HER2 polymorphisms. PATIENTS AND METHODS: In a retrospective cohort study of 237 women with non-metastatic HER2-positive breast cancer treated with trastuzumab, traditional risk factors were assessed by review of medical records, alcohol use by an administered questionnaire to women (n=132), and HER2 polymorphisms (Ile655Val and Ala1170Pro) using TaqMan assays (n=73). RESULTS: Association was observed between alcohol intake (10 drinks and more per week) during the trastuzumab treatment and cardiac toxicity (p=0.04). For polymorphisms, compared to Ile/Ile carriers, HER2 Ile/Val was associated with a higher risk of cardiac toxicity (p=0.02). CONCLUSION: Heavy alcohol use during the course of trastuzumab treatment and the HER2 Ile/Val genotype may constitute risk factors for cardiac toxicity.