Prediction of doxorubicin cardiotoxicity by early detection of subclinical right ventricular dysfunction

Cardiac PET Imaging of ATP Binding Cassette (ABC) Transporters: Opportunities and Challenges

Adenosine triphosphate binding cassette (ABC) transporters are a broad family of membrane protein complexes that use energy to transport molecules across cells and/or intracellular organelle lipid membranes. Many drugs used to treat cardiac diseases have an affinity for these transporters. Among others, P-glycoprotein (P-gp) plays an essential role in regulating drug concentrations that reach cardiac tissue and therefore contribute to cardiotoxicity. As a molecular imaging modality, positron emission tomography (PET) has emerged as a viable technique to investigate the function of P-gp in organs and tissues. Using PET imaging to evaluate cardiac P-gp function provides new insights for drug development and improves the precise use of medications. Nevertheless, information in this field is limited. In this review, we aim to examine the current applications of ABC transporter PET imaging and its tracers in the heart, with a specific emphasis on P-gp. Furthermore, the opportunities and challenges in this novel field will be discussed.

Detection of right ventricular dysfunction by three - dimensional echocardiography and two - dimensional speckle tracking in breast cancer patients receiving anthracycline- based chemotherapy

BACKGROUND

Despite the cardiotoxic effect of anthracycline on the left ventricle (LV) was totally identified. The assessment of the anthracycline effect on the right ventricle(RV) by conventional echocardiography was a challenge due to its complex geometry. We aimed to evaluate the impact of anthracycline on the RV volume and function using 3 dimensional -echocardiography (3DE) and 2 dimensional -speckle tracking echocardiography (2D-STE) in patients with breast cancer.

METHODS

This prospective study was conducted on 66 female patients with breast cancer receiving anthracycline chemotherapy, in addition to full echocardiography, 2D-STE and 3DE evaluation of RV function and volume were done at baseline, after 4th cycle of chemotherapy, six and nine months after the end of chemotherapy.

RESULTS

Cardiotoxicity from anthracycline occurred in 18 patients whose LV ejection fraction became significantly reduced after 9 months of therapy according to that, the patients were divided into the non-cardiotoxic group (n:48) and the cardiotoxic group (n:18). At cardiotoxic group, 3D RV end-systolic volume, and 3D RV end-diastolic volume increased significantly at 6 months and continued till 9 months after the therapy end compared to baseline values (42.50 ± 5.98 vs. 50.44 ± 7.01, p = 0.005) and (86.78 ± 9.16 vs. 95.78 ± 9.23, p = 0.021).LV global longitudinal strain (GLS) showed a significant reduction early after 6 months of therapy, 2D GLS and free wall longitudinal strain (FWLS) of RV were significantly decreased at 6 months and continued till 9 months after therapy (-22.54 ± 0.79 vs. -19.53 ± 1.32, p = 0.001) and (-24.67 ± 1.27vs. -22.22 ± 1.41, p = 0.001) respectively. The variation of RV FWLS was a predictor of cardiotoxicity, the relative drop of RV FWLS > 19.3% had 83% sensitivity and 71% specificity, (AUC = 0.82) to identify patients who developed cardiotoxicity.

CONCLUSION

3DE is a promising modality in recognizing the early changes in RV volumes and minute alteration in RV function and 2D-STE is a reliable predictor of RV systolic dysfunction which identify the subclinical affliction.

Neurotoxic Effect of Doxorubicin Treatment on Cardiac Sympathetic Neurons

Doxorubicin (DOXO) remains amongst the most commonly used anti-cancer agents for the treatment of solid tumors, lymphomas, and leukemias. However, its clinical use is hampered by cardiotoxicity, characterized by heart failure and arrhythmias, which may require chemotherapy interruption, with devastating consequences on patient survival and quality of life. Although the adverse cardiac effects of DOXO are consolidated, the underlying mechanisms are still incompletely understood. It was previously shown that DOXO leads to proteotoxic cardiomyocyte (CM) death and myocardial fibrosis, both mechanisms leading to mechanical and electrical dysfunction. While several works focused on CMs as the culprits of DOXO-induced arrhythmias and heart failure, recent studies suggest that DOXO may also affect cardiac sympathetic neurons (cSNs), which would thus represent additional cells targeted in DOXO-cardiotoxicity. Confocal immunofluorescence and morphometric analyses revealed alterations in SN innervation density and topology in hearts from DOXO-treated mice, which was consistent with the reduced cardiotropic effect of adrenergic neurons in vivo. Ex vivo analyses suggested that DOXO-induced denervation may be linked to reduced neurotrophic input, which we have shown to rely on nerve growth factor, released from innervated CMs. Notably, similar alterations were observed in explanted hearts from DOXO-treated patients. Our data demonstrate that chemotherapy cardiotoxicity includes alterations in cardiac innervation, unveiling a previously unrecognized effect of DOXO on cardiac autonomic regulation, which is involved in both cardiac physiology and pathology, including heart failure and arrhythmias.

Right ventricular dysfunction during chemotherapy in patients with breast cancer

Aim. To assess the right ventricle (RV) during chemotherapy (CT) in patients with breast cancer (BC).

Material and methods. The study included 40 women aged 35-72 years with BC who underwent anthracycline chemotherapy. The main group (n=40) included women with BC, examined at the first contact, 37 of whom were reexamined after 6 months. Control group (n=25) included women without BC.

Results. In the main group, the median transverse dimension and anterior wall thickness of the RV were significantly greater than in the control group (p<0,001). Early diastolic transtricuspid flow velocity (Et) after 6 months was lower than in the control group (p=0,003). The ratio of Et to late (At) diastolic transtricuspid flow (Et/At) in BC patients significantly decreased during the follow-up period (p<0,05) when compared with the control group and baseline values. Higher values of Tei index were noted in the main group compared to the control one (p<0,05). Using logistic regression for the Tei index, the model included radiation therapy, the total anthracycline dose, and negative affectivity score as follows: F(3,17)=12,548, p<0,001, R2=0,729. For the Et/At ratio, additional radiation therapy and heart rate were significant factors as follows: F(2,16)=12,548, p=0,005, R2=0,526.

Conclusion. Against the background of CT, deterioration of RV systolic (increase in Tei index and RV volume) and diastolic (decrease in Et and Et/At ratio) function was noted.

Prevalence of Right Ventricle Strain Changes following Anthracycline Therapy

Background: Anthracycline (ANT) is the most recognized therapy known to cause cardiotoxicity, mainly left ventricle (LV) dysfunction. Global Longitudinal Strain (GLS) is the optimal tool for assessment of subclinical LV dysfunction. Right ventricle (RV) function has been recognized as an independent factor for cardiac outcomes; however, data evaluating RV GLS is limited. We aimed to evaluate the change in RV GLS following ANT therapy. Methods: The study cohort is part of the Israel Cardio-Oncology Registry (ICOR). All patients performed echocardiography before (T1) and at the end (T3) of ANT therapy. A significant reduction was defined as a relative reduction of ≥10% in RV GLS values. Results: The study included 40 female patients with breast cancer treated with ANT. During follow-up, both RV GLS and free wall longitudinal strain systolic peak (RV FWLS PK) decreased significantly (p < 0.001 and p = 0.002). Altogether, 30 (75%) and 23 (58%) patients showed RV GLS and RV FWLS PK ≥ 10% relative reduction. At T3, LV ejection fraction and LV GLS were within normal range. Conclusions: RV GLS and RV FWLS PK reduction following ANT exposure is extremely frequent, comparing to LV GLS reduction.

Evaluating Right Ventricular Function To Reveal Cancer Therapy Cardiotoxicity

Advances in cancer treatment resulted in augmented patient survival rate. However, anticancer therapy often causes heart damage in the form of a progressive systolic heart failure. Echocardiographic parameters of left ventricular function were conventionally used to detect early manifestations of cancer therapy cardiotoxicity. Improved diagnosing of the right ventricle condition revealed that it is negatively affected by chemotherapy as frequently as the left ventricle, and sometimes even earlier than the latter. Hence, currently, the right ventricle function and mechanics assessment techniques are actively developed for the chemotherapy cardiotoxicity diagnostic, primarily employing 3D echocardiography and speckle tracking analysis. The presented review provides relevant information on the matter and highlights insufficiently developed issues and fields of further research.

The Utility of Advanced Cardiovascular Imaging in Cancer Patients-When, Why, How, and the Latest Developments

Cardio-oncology encompasses the risk stratification, prognostication, identification and management of cancer therapeutics related cardiac dysfunction (CTRCD). Cardiovascular imaging (CVI) plays a significant role in each of these scenarios and has broadened from predominantly quantifying left ventricular function (specifically ejection fraction) to the identification of earlier bio-signatures of CTRCD. Recent data also demonstrate the impact of chemotherapy on the right ventricle, left atrium and pericardium and highlight a possible role for CVI in the identification of CTRCD through tissue characterization and assessment of these cardiac chambers. This review aims to provide a contemporary perspective on the role of multi-modal advanced cardiac imaging in cardio-oncology.

Cardiac magnetic resonance assessment of right ventricular remodeling after anthracycline therapy

There are limited data on the effects of anthracyclines on right ventricular (RV) structure, function, and tissue characteristics. The goal of this study was to investigate the effects of anthracyclines on the RV using cardiac magnetic resonance (CMR). This was a post-hoc analysis of a prospective study of 27 breast cancer (BC) patients (51.8 ± 8.9 years) using CMR prior, and up to 3-times after anthracyclines (240 mg/m²) to measure RV volumes and mass, RV extracellular volume (ECV) and cardiomyocyte mass (CM). Before anthracyclines, LVEF (69.4 ± 3.6%) and RVEF (55.6 ± 9%) were normal. The median follow-up after anthracyclines was 399 days (IQR 310–517). The RVEF reached its nadir (46.3 ± 6.8%) after 9-months (P < 0.001). RV mass-index and RV CM decreased to 13 ± 2.8 g/m² and 8.13 ± 2 g/m², respectively, at 16-months after anthracyclines. The RV ECV expanded from 0.26 ± 0.07 by 0.14 (53%) to 0.40 ± 0.1 (P < 0.001). The RV ECV expansion correlated with a decrease in RV mass-index (r = −0.46; P < 0.001) and the increase in CK-MB. An RV ESV index at baseline above its median predicted an increased risk of LV dysfunction post-anthracyclines. In BC patients treated with anthracyclines, RV atrophy, systolic dysfunction, and a parallel increase of diffuse interstitial fibrosis indicate a cardiotoxic response on a similar scale as previously seen in the systemic left ventricle.