Radiation-Associated Cardiac Disease: From Molecular Mechanisms to Clinical Management

Progression of coronary artery calcification after radiation therapy for esophageal cancer

BACKGROUND

Advances in cancer treatment have resulted in increased attention toward potential cardiac complications, especially following treatment for esophageal cancer, which is associated with a risk of coronary artery disease. As the heart is directly irradiated during radiotherapy, coronary artery calcification (CAC) may progress in the short term. Therefore, we aimed to investigate the characteristics of patients with esophageal cancer that predispose them to coronary artery disease, CAC progression on PET-computed tomography and the associated factors, and the impact of CAC progression on clinical outcomes.

METHODS

We retrospectively screened 517 consecutive patients who received radiation therapy for esophageal cancer from our institutional cancer treatment database between May 2007 and August 2019. CAC scores were analyzed clinically for 187 patients who remained by exclusion criteria.

RESULTS

A significant increase in the Agatston score was observed in all patients (1 year: P  = 0.001*, 2 years: P  < 0.001*). Specifically for patients receiving middle-lower chest irradiation (1 year: P  = 0.001*, 2 years: P  < 0.001*) and those with CAC at baseline (1 year: P  = 0.001*, 2 years: P  < 0.001*), a significant increase in the Agatston score was observed. There was a trend for a difference in all-cause mortality between patients who had irradiation of the middle-lower chest ( P  = 0.053) and those who did not.

CONCLUSION

CAC can progress within 2 years after the initiation of radiotherapy to the middle or lower chest for esophageal cancer, particularly in patients with detectable CAC before radiotherapy initiation.

Bradyarrhythmias in Cardio-Oncology

The relationship between bradyarrhythmias and cancer therapies has not been well described but is increasingly recognized. There have been extensive advances in oncological pharmacotherapy, with several new classes of drugs available including targeted agents, immune checkpoint inhibitors and CAR T cell therapy. This increasing repertoire of available drugs has revolutionized overall prognosis and survival of cancer patients but the true extent of their cardiovascular toxicity is only beginning to be understood. Previous studies and published reviews have traditionally focused on conventional chemotherapies and in arrhythmias in general, particularly tachyarrhythmias. The number of patients with both cancer and cardiovascular problems is increasing globally and oncologists and cardiologists need to be adept at managing arrythmia based scenarios. Greater collaboration between the two specialties including studies with prospective data collection in Cardio-Oncology are much needed to fill in knowledge gaps in this arena. This case-based review summarizes current available evidence of cancer treatment-related bradyarrhythmia incidence (including its different subtypes), possible mechanisms and outcomes. Furthermore, we propose a stepwise surveillance and management protocol for patients with suspected bradyarrhythmia related to cancer treatment.

Cardiologic Long-Term Follow-Up of Patients Treated With Chest Radiotherapy: When and How?

Introduction: Radiotherapy may cause valvular (VHD), pericardial, coronary artery disease (CAD), left ventricular dysfunction (LVD), arrhythmias. The risk of radiation induced heart disease (RIHD) increases over time. The current guidelines suggest a screening for RIHD every 5 years in the long-term survivors who had been treated by chest RT.

Methods: We reviewed the clinical and instrumental data of 106 patients diagnosed with RIHD. In one group (Group A: 69 patients) RIHD was diagnosed in an asymptomatic phase through a screening with ECG, echocardiogram and stress test. A second group (37 patients) was seen when RIHD was symptomatic. We compared the characteristics of the two groups at the time of RT, of RIHD detection and at last follow-up.

Results: Overall, 64 patients (60%) had CAD (associated to other RIHD in 18); 39 (36.7%) had LVD (isolated in 20); 24 (22.6%) had VHD (isolated in 10 cases). The interval between the last negative test and the diagnosis of moderate or severe RIHD was <5 years in 26 patients, and <4 years in 18. In group A, 63% of the patients with CAD had silent ischemia. The two groups did not differ with regard to type of tumor, cardiovascular risk factors, use of anthracycline-based chemotherapy, age at RT treatment, radiation dose and interval between RT and toxicity detection. The mean time from RT and RIHD was 16 years in group A and 15 in group B. Interventional therapy at RIHD diagnosis was more frequent in group B (54 vs. 30%, p < 0.05). At last follow-up, 27 patients had died (12 of cancer, 9 of cardiac causes, 6 of other causes); mean ejection fraction was 60% in group A and 50% in group B (p < 0.01). Patients with ejection fraction ≤ 50% were 14.5% in group A and 40% in group B (p < 0.01).

Conclusions: Clinically relevant RIHD become evident at a mean interval of 16 years after RT. The most frequent clinical manifestations are CAD and LVD. RIHD diagnosis in asymptomatic patients may preserve their cardiac function with timely interventions. We suggest -after 10 years from radiotherapy- a screening every 2–3 years.

Cardiorespiratory fitness and physical performance after childhood hematopoietic stem cell transplantation: a systematic review and meta-analysis

The effects of childhood hematopoietic stem cell transplantation (HSCT) on key organs can impair cardiorespiratory fitness, muscle strength, and physical performance. We aimed to provide an overview of childhood HSCT survivors' status on these parameters compared with healthy controls and discuss current insights into clinical risk factors. We performed a systematic search in six scientific databases, including studies published before April 2019 and performed a meta-analysis on cardiorespiratory fitness. Muscle strength and physical performance status were presented narratively. We included ten studies embodying 517 childhood HSCT survivors (mean 17.8 years at follow-up). The meta-analysis (n = 4 studies) showed that childhood HSCT survivors have lower cardiorespiratory fitness compared with healthy controls (Standard mean difference (SMD) -1.32 [95% CI -1-58 to -1.07]; I² 2%, p < 0.00001). Collectively, the studies indicated that childhood HSCT survivors have lower muscle strength (n = 4 studies) and physical performance (n = 3 studies) compared with healthy controls. Childhood HSCT survivors have impaired cardiorespiratory fitness years after ended treatment. Muscle strength and physical performance seem to be impaired, although these measures are insufficiently investigated. Associations between HSCT-specific clinical risk factors and cardiorespiratory fitness, muscle strength, and physical performance are required.

Radiation-Associated Valvular Disease

PURPOSE OF REVIEW

Radiation-associated valvular disease (RAVD) is characterized by late valvular manifestations following radiation exposure to the mediastinum. Review of current guidelines was performed to examine best practices to reduce risk and optimize outcomes in this patient population.

RECENT FINDINGS

Early and consistent screening and comprehensive and careful planning are critical in managing RAVD. Due to long latency periods, serial screening and targeted evaluation of risk factors are essential to early detection. Varying and complex presentations of RAVD require an integrated team of experienced specialists equipped with multimodality imaging-based screening protocols to stratify risk, plan intervention, and evaluate treatment response. Patients with valvular manifestations associated with radiation therapy call for an individualized plan of care involving longitudinal multimodality imaging-based screening and experienced decision-making regarding timing and strategy of intervention to improve patient outcomes.