Radiation Toxicity to the Cardiovascular System

Chemotherapy induced right ventricular cardiomyopathy; a systematic review and meta-analysis

Background

Left ventricular dysfunction and cardiomyopathy are well documented adverse effects associated with chemotherapy agents. Limited information exists regarding the impact of chemotherapeutic agents on the integrity and function of the right ventricle (RV).

Objectives

The current metanalysis compared pre- chemotherapy versus post- chemotherapy RV parameters measured on 2D echocardiography in patients receiving anthracycline and/or trastuzumab across all breast cancer patients.

Methods

A systematic search across PubMed, EMBASE and Cochrane databases were performed from inception of the databases until November 2021 for relevant studies. We used the inverse variance method with a random effect model and DerSimonian and Laird method of Tau2 generation to calculate mean difference [MD] with 95% confidence interval [CI]. The analysis was carried out using RevMan Version 5.3 (Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2014).

Results

Fifteen studies, constituting total of 644 patients, met the inclusion criteria, with most studies having a follow up period of less than 12 months from initiation of chemotherapy. Anthracycline and/or Trastuzumab chemotherapy resulted in a statistically significant reduction in right ventricular ejection fraction (RVEF) at follow-up [MD: 2.70, 95% CI: 0.27 to 5.13, P-value- 0.03, I2- 71%, χ2 P-value < 0.05]. Treatment with Anthracycline and/or Trastuzumab chemotherapy resulted in a significant reduction in RV fractional area change (RVFAC) at follow-up [MD: 3.74, 95% CI: 1.33 to 6.15, P-value < 0.01, I2- 68%, χ2 P-value < 0.05]. RV free wall longitudinal strain (RVFWLS) was lower at baseline, while LVEF was significantly reduced at follow-up [MD: -1.00, 95% CI: -1.86 to -0.15, P-value < 0.05, I2- 0%, χ2 P-value-0.40], [MD: 4.04, 95% CI: 2.08 to 6.01, P-value < 0.01, I2- 91%, χ2 P-value < 0.05], respectively. However, treatment with Anthracycline and/or Trastuzumab chemotherapy had no statistically significant effect on Tricuspid annular plane systolic excursion (TAPSE) at follow-up [MD: 0.53, 95% CI: -0.11 to 1.17, P-value-0.11, I2- 98%, χ2 P-value < 0.05].

Conclusions

Chemotherapy with anthracyclines and trastuzumab negatively affects right ventricular function leading to decline in RVEF, RVFAC, RVFWLS and LVEF.

Association between cancer history and second-generation drug-eluting stent thrombosis: insights from the REAL-ST registry

BACKGROUND

Cancer-associated thrombosis is a frequent complication of cancer; however, little evidence is available regarding the association between cancer history and coronary artery stent thrombosis (ST). We aimed to investigate the relationship between cancer history and second-generation drug-eluting stent thrombosis (G2-ST).

METHODS

From the REAL-ST (Retrospective Multicenter Registry of ST After First- and Second-Generation Drug-Eluting Stent Implantation) registry, this study evaluated 1265 patients (G2- ST cases, n = 253; controls, n = 1012) with cancer-related information available.

RESULTS

The prevalence of patients with cancer history was higher (12.3% vs. 8.5%, p = 0.065), and that of currently diagnosed and currently treated cancer was significantly higher in ST cases than controls (3.6% vs. 1.4%, p = 0.021; 3.2% vs. 1.3%, p = 0.037, respectively). Multivariable logistic regression analysis revealed that cancer history was associated with late ST (odds ratio [OR]: 2.80, 95% confidence intervals [CI]: 0.92-8.55, p = 0.071) and very late ST (OR: 2.40, 95% CI: 1.02-5.65, p = 0.046), but not with early ST (OR: 1.01, 95% CI: 0.51-2.00, p = 0.97). During the median follow-up period of 872 days after the index ST events, patients with cancer history showed a higher mortality than those without, among both ST cases (hazard ratio [HR]: 1.93, 95% CI: 1.06-3.51, p = 0.031) and controls (HR: 1.93, 95% CI: 1.09-3.40, p = 0.023).

CONCLUSION

A post hoc analysis of REAL-ST registry revealed that patients with G2-ST had a higher prevalence of currently diagnosed and currently treated cancer. Notably, cancer history was associated with the occurrence of late and very late ST, but not with early ST.

Cancer treatment-related cardiac dysfunction

OBJECTIVES

This paper describes cardiotoxicity and cancer treatment-related cardiac dysfunction (CTRCD). Long-term sequelae of treatment are important, and changing, and may manifest when a patient is under the care of a supportive care service.

METHODS

Key messages for supportive and palliative care clinicians are outlined to facilitate identification and management of CTRCD.

RESULTS

Not all cardiotoxicity is alike. Types of cardiotoxicity, cardiac complications of immunotherapy, the challenge of autonomic nervous system dysfunction in cancer and management of cardiotoxicity are highlighted.

CONCLUSIONS

The key strategies are early detection of cardiotoxicity, monitoring for development of CTRCD during treatment and surveillance in survivorship.

Prognosis of patients with active cancer undergoing transcatheter aortic valve implantation: An insight from Japanese multicenter registry

Background

Malignancy is common in older adults undergoing transcatheter aortic valve implantation (TAVI), and may affect prognosis. The present study aimed to examine whether active cancer affects all-cause mortality rates among patients undergoing TAVI.

Methods

This retrospective study examined data from 1,114 consecutive patients treated between April 2010 and June 2019. Patients with life expectancy of <1 year due to non-cardiac causes were excluded.

Results

Active cancer was defined as cancer under treatment or cured within 1 year, and was recognized in 62 patients (5.6%) with (n = 17) and without (n = 45) metastases. In multivariate analysis, being female (hazard ratio [HR] 0.55, 95% confidence interval [CI] 0.39–0.77, p < 0.001), body mass index (BMI) (HR = 0.92 per 1 kg/m² increase, 95% CI 0.87–0.97, p = 0.001), New York Heart Association (NYHA) class III/IV (HR = 1.53, 95% CI 1.06–2.20, p = 0.022), atrial fibrillation (HR = 2.40, 95% CI 1.70–3.38, p < 0.001), albumin levels (HR = 0.41 per 1-g/dl, 95% CI 0.30–0.57, p < 0.001), and cancer metastasis (HR = 5.28, 95% CI 1.86–14.9, p = 0.001) were associated with all-cause mortality after TAVI.

Conclusion

In patients undergoing TAVI, being female, high BMI, NYHA class III/IV, atrial fibrillation, albumin levels, and cancer metastasis were factors associated with mortality. Meanwhile, active cancer without metastasis was not associated with increased mortality rates. These findings would help clinical decision-making by patients and physicians.

Clinical trial registration: UMIN000031133.

Cardiac stereotactic ablative radiotherapy for control of refractory ventricular tachycardia: initial UK multicentre experience

Background

Options for patients with ventricular tachycardia (VT) refractory to antiarrhythmic drugs and/or catheter ablation remain limited. Stereotactic radiotherapy has been described as a novel treatment option.

Methods

Seven patients with recurrent refractory VT, deemed high risk for either first time or redo invasive catheter ablation, were treated across three UK centres with non-invasive cardiac stereotactic ablative radiotherapy (SABR). Prior catheter ablation data and non-invasive mapping were combined with cross-sectional imaging to generate radiotherapy plans with aim to deliver a single 25 Gy treatment. Shared planning and treatment guidelines and prospective peer review were used.

Results

Acute suppression of VT was seen in all seven patients. For five patients with at least 6 months follow-up, overall reduction in VT burden was 85%. No high-grade radiotherapy treatment-related side effects were documented. Three deaths (two early, one late) occurred due to heart failure.

Conclusions

Cardiac SABR showed reasonable VT suppression in a high-risk population where conventional treatment had failed.

TAVR in Cancer Patients: Comprehensive Review, Meta-Analysis, and Meta-Regression

Objectives: This study sought to systematically analyze the available clinical evidence on TAVR therapy in cancer patients with symptomatic severe AS.

Background: Aortic stenosis is the most common valvular heart disease in the world. TAVR has expanded the treatment options for this lethal disease process. The safety and efficacy of TAVR in cancer patients has not yet been reliably established. We thus conducted the largest known multi-center meta-analysis on TAVR and cancer status.

Methods: We performed a literature search using PubMed, EMBASE, and Cochrane Central Register of Controlled Trials from January 2015 to 2020. Studies that compared the use of TAVR in patients with severe symptomatic aortic stenosis and cancer against patients without cancer were included. Meta-regression was also conducted to determine if common clinical factors modified the possible association between cancer status and TAVR mortality.

Results: Five studies with 11,129 patients in the cancer group and 41,706 patients in the control group met inclusion criteria. The short-term mortality in the cancer group was 2.4% compared with 3.3% in the control group (odds ratio: 0.72, 95% confidence interval: 0.63–0.82; p < 0.0001). The frequency of stroke was 2.4% compared with 2.7% (odds ratio of 0.87, 95% confidence interval: 0.76–0.99; p < 0.04). The frequency of AKI was 14.2% in cancer patients vs. 16.4% (odds ratio of 0.81, 95% confidence interval: 0.76–0.85; p < 0.04). The rates of bleeding and need for new pacemaker implantation were not significantly different. Meta-regression demonstrated there was no significant association modifying.

Conclusions: On the basis of the results of this meta-analysis TAVR may be a safe and effective therapeutic option for patients with cancer and symptomatic severe aortic stenosis. Larger, longer, and randomized trials are required to adequately test this above hypothesis.

Anthracyclines and regional myocardial damage in breast cancer patients. A multicentre study from the Working Group on Drug Cardiotoxicity and Cardioprotection, Italian Society of Cardiology (SIC)

AIMS

In breast cancer (BC) patients treated with anthracyclines-based therapies, we aim at assessing whether adjuvant drugs impact cardiac function differently and whether their cardiotoxicity has a regional pattern.

METHODS AND RESULTS

In a multicentre study, 146 BC patients (56 ± 11 years) were prospectively enrolled and divided into three groups according to the received treatments: AC/EC-Group (doxorubicin or epirubicin + cyclophosphamide), AC/EC/Tax-Group (AC/EC + taxanes), FEC/Tax-Group (fluorouracil + EC + taxanes). Fifty-six patients of the total cohort also received trastuzumab. Left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) were calculated before starting chemotherapy (T0), at 3 months (T3), at 6 (T6), and 12 months (T12). A ≥10% drop of EF, while remaining within the normal range, was reached at T6 in 25.3% of patients from the whole cohort with an early decrease only in FEC/Tax-Group (P = 0.04). A ≥15% GLS reduction was observed in many more (61.6%) patients. GLS decreased early both in the whole population (P < 0.001) and in the subgroups. The FEC-Tax Group showed the worst GLS at T6. Trastuzumab further worsened GLS at T12 (P = 0.031). A significant reduction of GLS was observed in all LV segments and was more relevant in the anterior septum and apex.

CONCLUSIONS

The decrease of GLS is more precocious and pronounced in BC patients who received FEC + taxanes. Cardiac function further worsens after 6 months of adjuvant trastuzumab. All LV segments are damaged, with the anterior septum and the apex showing the greatest impairments.

Morphological Plaque Characteristics and Clinical Outcomes in Patients With Acute Coronary Syndrome and a Cancer History

Background

Although patients with a cancer history have a 2 to 3 times higher risk for acute coronary syndrome (ACS), the morphological characteristics of ACS culprit plaque in those patients and their relations with clinical outcomes remain unknown.

Methods and Results

This retrospective, multicenter, observational cohort study included consecutive patients with ACS who underwent optical coherence tomography‐guided emergent percutaneous coronary intervention. Patients were categorized into those without a cancer history, those with a cancer history, and those currently receiving cancer treatment. ACS culprit lesions were classified as plaque rupture, plaque erosion, or calcified nodule using optical coherence tomography. Plaque erosion frequency was significantly higher in culprit lesions of patients with current cancer and patients with cancer history than in those of patients without cancer history (56.3% versus 61.7% versus 36.5%). Calcified nodule incidence was significantly higher in patients without cancer history than in patients with current cancer and patients without cancer history (patients with current cancer: 12.4% versus patients without cancer history: 25.5% versus patients without cancer history: 12.6%, P<0.001). Cancer history was independently associated with nonplaque rupture (plaque erosion or calcified nodule) in ACS culprit lesions (odds ratio, 4.00; P<0.001). Cancer history was independently associated with major adverse cardiovascular events (hazard ratio [HR], 1.98; P=0.002). Nonplaque rupture in ACS culprit lesions was independently associated with major adverse cardiovascular events (HR, 1.60; P=0.011).

Conclusions

Patients with a cancer history had significantly worse clinical outcomes after ACS than those without a cancer history. Those with a cancer history had significantly higher plaque erosion and calcified nodule incidences in the ACS culprit lesions, which might partly explain their worse clinical outcomes.

Registration

URL: www.umin.ac.jp/ctr/index.htm. Unique Identifier: UMIN000038442.

Clinical Experience and Recent Advances in the Development of Listeria-Based Tumor Immunotherapies

The promise of tumor immunotherapy to significantly improve survival in patients who are refractory to long-standing therapies, such as chemotherapy and radiation, is now being realized. While immune checkpoint inhibitors that target PD-1 and CTLA-4 are leading the charge in clinical efficacy, there are a number of other promising tumor immunotherapies in advanced development such as Listeria-based vaccines. Due to its unique life cycle and ability to induce robust CTL responses, attenuated strains of Listeria monocytogenes (Lm) have been utilized as vaccine vectors targeting both infectious disease and cancer. In fact, preclinical studies in a multitude of cancer types have found Listeria-based vaccines to be highly effective at activating anti-tumor immunity and eradicating tumors. Several clinical trials have now recently reported their results, demonstrating promising efficacy against some cancers, and unique challenges. Development of the Lm-based immunotherapies continues with discovery of improved methods of attenuation, novel uses, and more effective combinatorial regimens. In this review, we provide a brief background of Listeria monocytogenes as a vaccine vector, discuss recent clinical experience with Listeria-based immunotherapies, and detail the advancements in development of improved Listeria-based vaccine platforms and in their utilization.

Microtubule Inhibitors and Cardiotoxicity

PURPOSE OF REVIEW

Cancer and heart disease are the leading causes of mortality in the USA. Advances in cancer therapies, namely, the development and use of chemotherapeutic agents alone or in combination, are becoming increasingly prevalent.

RECENT FINDINGS

Many chemotherapeutic agents have been associated with adverse cardiovascular manifestations. The mechanisms of these sequelae remain incompletely understood. In particular, microtubule inhibitor (MTI) agents have been related to the development of heart failure, myocardial ischemia, and conduction abnormalities. At present, there are no guidelines for patients undergoing MTI therapy as it pertains to both preventative and mitigatory strategies for cardiovascular complications. We conducted a literature review focusing on content related to the use of MTIs and their effect on the cardiovascular system. MTIs have been associated with various forms of cardiotoxicity, and fatal cardiotoxicities are rare. The most well-described cardiotoxicities are brady- and tachyarrhythmias. The co-administration of anthracycline-based agents with MTIs can increase the risk of cardiotoxicity.

Cardiotoxicity and cardiac monitoring following the use of radiotheranostics agents including 177Lu-PSMA for prostate cancer and 177Lu-DOTATATE for neuroendocrine tumors

BACKGROUND

 The aim of this study was to determine the probable cardiotoxicity following radionuclide therapy (RNT), specifically peptide receptor radionuclide therapy (PRRT) with ¹⁷⁷Lu-DOTATATE and radioligand therapy (RLT) with ¹⁷⁷Lu-PSMA by evaluation of serum troponin I and cardiac profile change during a follow-up time.

MATERIALS AND METHODS

 Patients with prostate cancer and neuroendocrine tumours (NETs) referred for PRRT and RLT, respectively, were enrolled in this study. The cardiac profiles of the patients were evaluated by a cardiologist and a cardiac history was obtained from all patients. Also, troponin I was measured before and 48 hours after treatment.

RESULTS

 In this retrospective study for assessment of RLT associated cardiotoxicity, 24 patients were evaluated with a median age of 64 years (27-99 years) including 13 NET patients and 11 prostate cancer patients. Patients were followed up for 4 to 31 months which no cardiovascular problem was observed. In evaluation of troponin I, 39 RNT cycles were evaluated. In all patients, the value of troponin I was in normal range. In all patients, the median values of serum troponin I before and after treatment were 0.2 ± 0.02 (range: 0.00-0.42) and 0.28 ± 0.02 (range: 0.00-0.46) ng/ml, respectively (p > 0.05). In the prostate cancer patients, the median values of serum troponin I before and after treatment were 0.26 ± 0.04 (0.04-0.42) and 0.30 ± 0.04 (0.00-0.41) ng/ml, respectively (p > 0.05). In the NET patients, the median values of serum troponin I before and after treatment were 0.18 ± 0.03 (0.00-0.42) and 0.17 ± 0.03 (0.00-0.46) ng/ml, respectively (p > 0.05).

CONCLUSION

 PRRT with ¹⁷⁷Lu-DOTATATE and RLT with ¹⁷⁷Lu-PSMA as emerging therapeutic modalities have no significant cardiotoxicity. However, further well-designed studies are recommended.

Acute coronary syndromes in cancer patients

: Cardiovascular disease and cancer are responsible for the majority of deaths in the Western world. These two entities share common risk factors and their intersection will be more and more frequent in future due to general population aging and long-term cancer control. Clinical presentation, management and outcome of acute coronary syndromes (ACS) in cancer patients could differ from noncancer ones. Cancer patients were frequently excluded from clinical trials and so the paucity of data further complicates the scenario. The management of ACS in cancer patients represents a unique setting in which the risk/benefit ratio of invasive treatment should be carefully evaluated. This review focused on the available evidence of all aspects of ACS in cancer patients providing a guide to a multidisciplinary approach.

Oxidative Stress in Radiation-Induced Cardiotoxicity

There is a distinct increase in the risk of heart disease in people exposed to ionizing radiation (IR). Radiation-induced heart disease (RIHD) is one of the adverse side effects when people are exposed to ionizing radiation. IR may come from various forms, such as diagnostic imaging, radiotherapy for cancer treatment, nuclear disasters, and accidents. However, RIHD was mainly observed after radiotherapy for chest malignant tumors, especially left breast cancer. Radiation therapy (RT) has become one of the main ways to treat all kinds of cancer, which is used to reduce the recurrence of cancer and improve the survival rate of patients. The potential cause of radiation-induced cardiotoxicity is unclear, but it may be relevant to oxidative stress. Oxidative stress, an accumulation of reactive oxygen species (ROS), disrupts intracellular homeostasis through chemical modification and damages proteins, lipids, and DNA; therefore, it results in a series of related pathophysiological changes. The purpose of this review was to summarise the studies of oxidative stress in radiotherapy-induced cardiotoxicity and provide prevention and treatment methods to reduce cardiac damage.

Emerging Challenges of Radiation-Associated Cardiovascular Dysfunction (RACVD) in Modern Radiation Oncology: Clinical Practice, Bench Investigation, and Multidisciplinary Care

Radiotherapy (RT) is a crucial treatment modality in managing cancer patients. However, irradiation dose sprinkling to tumor-adjacent normal tissues is unavoidable, generating treatment toxicities, such as radiation-associated cardiovascular dysfunction (RACVD), particularly for those patients with combined therapies or pre-existing adverse features/comorbidities. Radiation oncologists implement several efforts to decrease heart dose for reducing the risk of RACVD. Even applying the deep-inspiration breath-hold (DIBH) technique, the risk of RACVD is though reduced but still substantial. Besides, available clinical methods are limited for early detecting and managing RACVD. The present study reviewed emerging challenges of RACVD in modern radiation oncology, in terms of clinical practice, bench investigation, and multidisciplinary care. Several molecules are potential for serving as biomarkers and therapeutic targets. Of these, miRNAs, endogenous small non-coding RNAs that function in regulating gene expression, are of particular interest because low-dose irradiation, i.e., 200 mGy (one-tenth of conventional RT daily dose) induces early changes of pro-RACVD miRNA expression. Moreover, several miRNAs, e.g., miR-15b and miR21, involve in the development of RACVD, further demonstrating the potential bio-application in RACVD. Remarkably, many RACVDs are late RT sequelae, characterizing highly irreversible and progressively worse. Thus, multidisciplinary care from oncologists and cardiologists is crucial. Combined managements with commodities control (such as hypertension, hypercholesterolemia, and diabetes), smoking cessation, and close monitoring are recommended. Some agents show abilities for preventing and managing RACVD, such as statins and angiotensin-converting enzyme inhibitors (ACEIs); however, their real roles should be confirmed by further prospective trials.

Acute Coronary Syndrome Management in Cancer Patients

PURPOSE OF REVIEW

Coronary artery disease and cancer often co-exist. Patients with cancer have been excluded by most major cardiology trials and registries and their management remains largely empiric. Cancer patients experience an approximately 10-times increased mortality compared to the general population. Conservative therapy of ACS in cancer therapy results in 1-year mortality of 74%. This review article aims to describe the mechanisms of acute coronary syndromes in cancer patients, their clinical presentation, and their management.

RECENT FINDINGS

Newer studies have shed light on the mechanisms of ACS in cancer patients, which are different and related to the type of malignancy and its associated therapy. Medication-specific coronary effects (vasospasm, endothelial dysfunction, spontaneous thrombosis, accelerated atherosclerosis), radiation vasculitis, cancer cell coronary embolism, and coronary compression from thoracic malignancies are unique ACS mechanisms in cancer patients. Close collaboration between oncologists and cardiologists for thoughtful patient selection and decision making strategies is necessary to provide optimal medical care.

Pregnancy Among Survivors of Childhood Cancer: Cardiovascular Considerations

PURPOSE OF REVIEW

To educate clinicians on cardiovascular considerations and management strategies surrounding pregnancy in childhood cancer survivors.

RECENT FINDINGS

With advances in oncologic treatment, growing numbers of childhood cancer survivors are now able to consider pregnancy. A significant proportion of survivors have received cardiotoxic therapy, particularly anthracyclines, and/or chest radiation. Cardiomyopathy is the most common cardiac complication of cancer-directed therapy; pericardial disease, valvular disease, premature coronary artery disease, and conduction abnormalities are other potential sequelae. In female survivors of childhood malignancy, cardiac evaluation should be performed prior to pregnancy as subclinical disease has the potential to be unmasked by the hemodynamic stress of pregnancy. However, limited data exist on pregnancy outcomes after cancer survivorship. With appropriate management, maternal and fetal outcomes in pregnancy following childhood cancer are generally favorable. Further research is needed to understand the incidence of cardiac complications among childhood cancer survivors, strategies to prevent these complications, optimal cardiovascular management during pregnancy and the postpartum period, and on the impact of pregnancy itself on the natural history of treatment-related cardiotoxicity.

Long-term effects of low-dose mouse liver irradiation involve ultrastructural and biochemical changes in hepatocytes that depend on lipid metabolism

The aim of the study was to investigate long-term effects of radiation on the (ultra)structure and function of the liver in mice. The experiments were conducted on wild-type C57BL/6J and apolipoprotein E knock-out (ApoE^-/-) male mice which received a single dose (2 or 8 Gy) of X-rays to the heart with simultaneous exposure of liver to low doses (no more than 30 and 120 mGy, respectively). Livers were collected for analysis 60 weeks after irradiation and used for morphological, ultrastructural, and biochemical studies. The results show increased damage to mitochondrial ultrastructure and lipid deposition in hepatocytes of irradiated animals as compared to non-irradiated controls. Stronger radiation-related effects were noted in ApoE^-/- mice than wild-type animals. In contrast, radiation-related changes in the activity of lysosomal hydrolases, including acid phosphatase, β-glucuronidase, N-acetyl-β-D-hexosaminidase, β-galactosidase, and α-glucosidase, were observed in wild type but not in ApoE-deficient mice, which together with ultrastructural picture suggests a higher activity of autophagy in ApoE-proficient animals. Irradiation caused a reduction of plasma markers of liver damage in wild-type mice, while an increased level of hepatic lipase was observed in plasma of ApoE-deficient mice, which collectively indicates a higher resistance of hepatocytes from ApoE-proficient animals to radiation-mediated damage. In conclusion, liver dysfunctions were observed as late effects of irradiation with an apparent association with malfunction of lipid metabolism.

Radiation-Induced Coronary Artery Disease in Young Patients

Exposure to radiotherapy has been shown to accelerate myocardial damage or injury to the cardiac vasculature. Accelerated coronary artery disease (CAD) is one of the main manifestations of cardiac disease in patients who undergo mediastinal radiation therapy. We present the cases of three young patients who developed severe CAD secondary to remote mediastinal radiotherapy.

Heart irradiation reduces microvascular density and accumulation of HSPA1 in mice

PURPOSE

Improvement of radiotherapy techniques reduces the exposure of normal tissues to ionizing radiation. However, the risk of radiation-related late effects remains elevated. In the present study, we investigated long-term effects of radiation on heart muscle morphology.

MATERIALS AND METHODS

We established a mouse model to study microvascular density (MVD), deposition of collagen fibers, and changes in accumulation of heat shock 70 kDa protein 1 (HSPA1) in irradiated heart tissue. Hearts of C57BL/6 mice received a single dose of X‑ray radiation in the range 0.2-16 Gy. Analyses were performed 20, 40, and 60 weeks after irradiation.

RESULTS

Reduction in MD was revealed as a long-term effect observed 20-60 weeks after irradiation. Moreover, a significant and dose-dependent increase in accumulation of HSPA1, both cytoplasmic and nuclear, was observed in heart tissues collected 20 weeks after irradiation. We also noticed an increase in collagen deposition in hearts treated with higher doses.

CONCLUSIONS

This study shows that some changes induced by radiation in the heart tissue, such as reduction in microvessel density, increase in collagen deposition, and accumulation of HSPA1, are observed as long-term effects which might be associated with late radiation cardiotoxicity.

The Use of Primary Prevention Statin Therapy in Those Predisposed to Atherosclerosis

PURPOSE OF REVIEW

Many guidelines exist for the use of statins in the primary prevention of atherosclerotic cardiovascular disease (ASCVD). Few have focused on disease specific states that predispose to ASCVD. This review is intended to focus on the recommendations and evidence in inflammatory diseases that predispose to an increased risk of ASCVD beyond what conventional cardiac risk scores would predict.

RECENT FINDINGS

Certain autoimmune inflammatory diseases such as rheumatoid arthritis (RA), systemic lupus erythematous (SLE), and psoriasis/psoriatic arthritis have all been shown to increase the risk of ASCVD. Other diseases such as human immunodeficiency virus (HIV) and mediastinal radiation have also been correlated with increased ASCVD. In RA and HIV, the evidence suggests a benefit to added statin therapy and society guidelines favor early initiation. The evidence for statin therapy in RA is limited to observational studies with small secondary analysis. In HIV, there is a large ongoing clinical trial to assess efficacy. In those with psoriasis and psoriatic arthritis, there is limited evidence for or against statin therapy independent of a calculated cardiac risk score. Finally, in SLE and in those with exposure to mediastinal radiation, cardiac events remain high, but evidence is limited on the beneficial effects of statin therapy. There are many individuals who have an increased risk for ASCVD above what is predicted from a cardiac risk score. It would be beneficial to create risk prediction models with statin therapy recommendations that are tailored to those predisposed to accelerated atherosclerosis.

Radiation-Induced Cardiovascular Disease

PURPOSE OF REVIEW

Thoracic radiation therapy is an effective treatment for several malignancies, such as Hodgkin's lymphoma and breast cancer. Over the years, however, the incidence of cardiovascular events has increased in these patients, notably in younger survivors who do not have traditional risk factors. This review summarizes the pathology, incidence, clinical presentation, and management of cardiac events after radiation therapy.

RECENT FINDINGS

Mediastinal radiation therapy accelerates the atherosclerosis process, resulting in early onset coronary artery disease. Valvular disease due to radiation therapy typically affects the left-sided valves, with aortic regurgitation being the most common. Rarely, it may lead to aortic stenosis requiring surgical interventions. Pericardial involvement includes acute and chronic pericardial disease and pericardial effusion. New studies are investigating the prevalence and pathogenesis of autonomic dysfunction in cancer survivors who have undergone mediastinal and neck radiation. Radiation therapy itself causes vascular endothelial dysfunction, resulting in clinical cardiovascular events, manifesting many years after completion of therapy. There remains little guidance regarding screening and therapies to prevent cardiovascular events in this population.