Fibrotic aortic valve disease after radiotherapy: an immunohistochemical study in breast cancer and lymphoma patients

Diagnostic Value of Aortic Valve Calcification Levels in the Assessment of Low-Gradient Aortic Stenosis

BACKGROUND

In patients with low-gradient aortic stenosis (AS) and low transvalvular flow, dobutamine stress echocardiography (DSE) is recommended to determine AS severity, whereas the degree of aortic valve calcification (AVC) supposedly correlates with AS severity according to current European and American guidelines.

OBJECTIVES

The purpose of this study was to assess the relationship between AVC and AS severity as determined using echocardiography and DSE in patients with aortic valve area <1 cm2 and peak aortic valve velocity <4.0 m/s.

METHODS

All patients underwent DSE to determine AS severity and multislice computed tomography to quantify AVC. Receiver-operating characteristics curve analysis was used to assess the diagnostic value of AVC for AS severity grading as determined using echocardiography and DSE in men and women.

RESULTS

A total of 214 patients were included. Median age was 78 years (25th-75th percentile: 71-84 years) and 25% were women. Left ventricular ejection fraction was reduced (<50%) in 197 (92.1%) patients. Severe AS was diagnosed in 106 patients (49.5%). Moderate AS was diagnosed in 108 patients (50.5%; in 77 based on resting transthoracic echocardiography, in 31 confirmed using DSE). AVC score was high (≥2,000 for men or ≥1,200 for women) in 47 (44.3%) patients with severe AS and in 47 (43.5%) patients with moderate AS. AVC sensitivity was 44.3%, specificity was 56.5%, and positive and negative predictive values for severe AS were 50.0% and 50.8%, respectively. Area under the receiver-operating characteristics curve was 0.508 for men and 0.524 for women.

CONCLUSIONS

Multi-slice computed tomography-derived AVC scores showed poor discrimination between grades of AS severity using DSE and cannot replace DSE in the diagnostic work-up of low-gradient severe AS.

The role of cardiac surgery in radiation-associated heart disease: a scoping review

BACKGROUND

Thoracic irradiation is an important tool in the treatment of breast cancer, non-Hodgkin's lymphoma, and other cancers of the chest. The heart is commonly involved in these radiation fields, and young patients can present with severe cardiac pathologies requiring surgical intervention. However, this population poses a high surgical risk due to involvement of mediastinal tissues, and there are no consensus guidelines on best practice management.

AIM

This review aims to summarise the current experience of surgical correction of radiation-associated heart disease. We explore outcomes, technique modifications and alternative therapies for the three primary procedures performed: coronary artery bypass grafting, valvular intervention and pericardiectomy.

METHODS

OVID Medline and PubMed databases were comprehensively searched to identify all studies involving surgery in patients with prior chest radiotherapy. All relevant studies within the past 25 years have been discussed.

CONCLUSION

Irradiated patients have heightened peri-operative risk, but other than redo surgery, these operations are not as treacherous as once thought. Involvement of all layers of the heart, especially the myocardium, is such that long-term mortality suffers despite optimal surgical correction. The goal of surgery in this cohort should be for a quick and safe operation, rather than a technically difficult procedure aimed at longevity.

Cancer survivorship at heart: a multidisciplinary cardio-oncology roadmap for healthcare professionals

In cancer, a patient is considered a survivor from the time of initial diagnosis until the end of life. With improvements in early diagnosis and treatment, the number of cancer survivors (CS) has grown considerably and includes: (1) Patients cured and free from cancer who may be at risk of late-onset cancer therapy-related cardiovascular toxicity (CTR-CVT); (2) Patients with long-term control of not-curable cancers in whom CTR-CVT may need to be addressed. This paper highlights the importance of the cancer care continuum, of a patient-centered approach and of a prevention-oriented policy. The ultimate goal is a personalized care of CS, achievable only through a multidisciplinary-guided survivorship care plan, one that replaces the fragmented management of current healthcare systems. Collaboration between oncologists and cardiologists is the pillar of a framework in which primary care providers and other specialists must be engaged and in which familial, social and environmental factors are also taken into account.

Radiation-Induced Aortic Stenosis: An Update on Treatment Modalities

The adverse effects of radiation therapy for cancer are well described and can include a wide array of cardiac complications. Radiation-induced aortic stenosis (AS) is an increasingly recognized entity that poses particular therapeutic challenges. Several retrospective studies comparing the outcomes after transcatheter aortic valve replacement (TAVR) vs those after surgical aortic valve replacement patients with radiation-induced AS have found a trend toward decreased mortality and fewer major complications with TAVR. Surgical aortic valve replacement is associated with increased mortality in patients with radiation-induced AS compared with patients without a history of prior radiation. TAVR has been shown to be a safe and effective alternative in patients with radiation-induced AS, with safety similar to that for patients who have not received prior radiation. However, rare and unexpected complications may occur after TAVR from the deleterious effects of radiation on mediastinal structures. More studies are needed to identify the optimal way of managing patients with radiation-induced AS, and algorithms are needed for planning these complex interventions.

Cardiac computed tomographic imaging in cardio-oncology: An expert consensus document of the Society of Cardiovascular Computed Tomography (SCCT). Endorsed by the International Cardio-Oncology Society (ICOS)

Cardio-Oncology is a rapidly growing sub-specialty of medicine, however, there is very limited guidance on the use of cardiac CT (CCT) in the care of Cardio-Oncology patients. In order to fill in the existing gaps, this Expert Consensus statement comprised of a multidisciplinary collaboration of experts in Cardiology, Radiology, Cardiovascular Multimodality Imaging, Cardio-Oncology, Oncology and Radiation Oncology aims to summarize current evidence for CCT applications in Cardio-Oncology and provide practice recommendations for clinicians.

Mediastinal irradiation and valvular heart disease

Anticancer therapy has the potential to cause unwanted cardiovascular side effects. Utilization of radiation therapy to treat tumors near the heart can result in radiation-induced valvular heart disease among other cardiovascular pathologies. The aim of this review is to describe the epidemiology, pathophysiology, risk prediction, non-invasive imaging modalities and management of radiation-induced valvular heart disease with a focus on pre-operative risk assessment and contemporary treatment options.

Current view on radiation-induced heart disease and methods of its diagnosis

In recent years, cardiologists and cardiovascular surgeons are increasingly encountering radiation-induced heart disease (RIHD) in their practice. This complication is described in literature but is poorly understood and clinically challenging. Radiation therapy (RT) is widely used in the treatment of many cancers. Despite the considerable risk of RT complications, it is used in 20–55% of cancer patients. Radiation-associated cardiotoxicity appears to be delayed, typically 10 to 30 years following treatment. Mediastinal irradiation significantly increases the risk of non-ischemic cardiomyopathy. Recent reviews estimate the prevalence of radiation-induced cardiomyopathy at more than 10%. Therefore, it is important to understand the pathophysiology of RIHD, consider risk factors associated with radiation injury, and detect the condition early.

Nuclear medicine imaging methods of radiation-induced cardiotoxicity

Breast cancer survival is significantly improved over the past decades due to major improvements in anti-tumor therapies and the implementation of regular screening, which leads to early detection of breast cancer. Therefore, it is of utmost importance to prevent patients from long-term side effects, including radiotherapy-induced cardiotoxicity. Radiotherapy may contribute to damage of myocardial structures on the cellular level, which eventually could result in various types of cardiovascular problems, including coronary artery disease and (non-)ischemic cardiomyopathy, leading to heart failure. These cardiac complications of radiotherapy are preceded by alterations in myocardial perfusion and blood flow. Therefore, early detection of these alterations is important to prevent the progression of these pathophysiological processes. Several radionuclide imaging techniques may contribute to the early detection of these changes. Single-Photon Emission Computed Tomography (SPECT) cameras can be used to create Multigated Acquisition scans in order to assess the left ventricular systolic and diastolic function. Furthermore, SPECT cameras are used for myocardial perfusion imaging with radiopharmaceuticals such as ^99mTc-sestamibi and ^99mTc-tetrofosmin. Accurate quantitative measurement of myocardial blood flow (MBF), can be performed by Positron Emission Tomography (PET), as the uptake of some of the tracers used for PET-based MBF measurement almost creates a linear relationship with MBF, resulting in very accurate blood flow quantification. Furthermore, there are PET and SPECT tracers that can assess inflammation and denervation of the cardiac sympathetic nervous system. Research over the past decades has mainly focused on the long-term development of left ventricular impairment and perfusion defects. Considering laterality of the breast cancer, some early studies have shown that women irradiated for left-sided breast cancer are more prone to cardiotoxic side effects than women irradiated for right-sided breast cancer. The left-sided radiation field in these trials, which predominantly used older radiotherapy techniques without heart-sparing techniques, included a larger volume of the heart and left ventricle, leading to increased unavoidable radiation exposure to the heart due to the close proximity of the radiation treatment volume. Although radiotherapy for breast cancer exposes the heart to incidental radiation, several improvements and technical developments over the last decades resulted in continuous reduction of radiation dose and volume exposure to the heart. In addition, radiotherapy reduces loco-regional tumor recurrences and death from breast cancer and improves survival. Therefore, in the majority of patients, the benefits of radiotherapy outweigh the potential very low risk of cardiovascular adverse events after radiotherapy. This review addresses existing nuclear imaging techniques, which can be used to evaluate (long-term) effects of radiotherapy-induced mechanical cardiac dysfunction and discusses the potential use of more novel nuclear imaging techniques, which are promising in the assessment of early signs of cardiac dysfunction in selected irradiated breast cancer patients.

Radiation-Induced Cardiovascular Disease: Review of an Underrecognized Pathology

Radiation therapy demonstrates a clear survival benefit in the treatment of several malignancies. However, cancer survivors can develop a wide array of cardiotoxic complications related to radiation. This pathology is often underrecognized by clinicians and there is little known on how to manage this population. Radiation causes fibrosis of all components of the heart and significantly increases the risk of coronary artery disease, cardiomyopathy, valvulopathy, arrhythmias, and pericardial disease. Physicians should treat other cardiovascular risk factors aggressively in this population and guidelines suggest obtaining regular imaging once symptomatology is established. Patients with radiation‐induced cardiovascular disease tend to do worse than their traditional counterparts for the same interventions. However, there is a trend toward fewer complications and lower mortality with catheter‐based rather than surgical approaches, likely because radiation makes these patients poor surgical candidates. When appropriate, these patients should be referred for percutaneous management of valvulopathy and coronary disease.

Radiation Induces Valvular Interstitial Cell Calcific Response in an in vitro Model of Calcific Aortic Valve Disease

Background: Mediastinal ionizing radiotherapy is associated with an increased risk of valvular disease, which demonstrates pathological hallmarks similar to calcific aortic valve disease (CAVD). Despite advances in radiotherapy techniques, the prevalence of comorbidities such as radiation-associated valvular disease is still increasing due to improved survival of patients receiving radiotherapy. However, the mechanisms of radiation-associated valvular disease are largely unknown. CAVD is considered to be an actively regulated disease process, mainly controlled by valvular interstitial cells (VICs). We hypothesize that radiation exposure catalyzes the calcific response of VICs and, therefore, contributes to the development of radiation-associated valvular disease.

Methods and Results: To delineate the relationship between radiation and VIC behavior (morphology, calcification, and matrix turnover), two different in vitro models were established: (1) VICs were cultured two-dimensional (2D) on coverslips in control medium (CM) or osteogenic medium (OM) and irradiated with 0, 2, 4, 8, or 16 Gray (Gy); and (2) three-dimensional (3D) hydrogel system was designed, loaded with VICs and exposed to 0, 4, or 16 Gy of radiation. In both models, a dose-dependent decrease in cell viability and proliferation was observed in CM and OM. Radiation exposure caused myofibroblast-like morphological changes and differentiation of VICs, as characterized by decreased αSMA expression. Calcification, as defined by increased alkaline phosphatase activity, was mostly present in the 2D irradiated VICs exposed to 4 Gy, while after exposure to higher doses VICs acquired a unique giant fibroblast-like cell morphology. Finally, matrix turnover was significantly affected by radiation exposure in the 3D irradiated VICs, as shown by decreased collagen staining and increased MMP-2 and MMP-9 activity.

Conclusions: The presented work demonstrates that radiation exposure enhances the calcific response in VICs, a hallmark of CAVD. In addition, high radiation exposure induces differentiation of VICs into a terminally differentiated giant-cell fibroblast. Further studies are essential to elucidate the underlying mechanisms of these radiation-induced valvular changes.

Tailoring PTV expansion to improve the dosimetry of post modified radical mastectomy intensity-modulated radiotherapy for left-sided breast cancer patients by using 4D CT combined with cone beam CT

PURPOSE

Our study aimed to improve the dosimetry of post modified radical mastectomy intensity-modulated radiotherapy (PMRM-IMRT) for left-sided breast cancer patients by tailoring and minimizing PTV expansion three-dimensionally utilizing 4D CT combined with on-board cone beam CT (CBCT).

METHODS

We enrolled a total of 10 consecutive left-sided breast cancer patients to undergo PMRM-IMRT. We measured the intra-fractional CTV displacement attributed to respiratory movement by defining 9 points on the left chest wall and quantifying their displacement by using the 4D CT, and measured the inter-fractional CTV displacement resulting from the integrated effect of respiratory movement, thoracic deformation and set up errors by using CBCT. We created 3 different PMRM-IMRT plans for each of the patients using PTV_t (tailored PTV expansion three-dimensionally), PTV_0.5 and PTV_0.7 (isotropic 0.5- cm and isotropic 0.7- cm expanding margin of CTV), respectively. We performed paired samples t test to establish a hierarchy in terms of plan quality and dosimetric benefits. P < 0.05 was considered statistically significant.

RESULTS

The inter-fractional CTV displacement (2.6 ± 2.2 mm vertically, 2.8 ± 2.3 mm longitudinally, and 1.7 ± 1.2 mm laterally) measured by CBCT was much larger than the intra-fractional one (0.5 ± 0.5 mm vertically, 0.5 ± 1.0 mm longitudinally, and 0.3 ± 0.3 mm laterally, respectively) measured by 4D CT. Intensity-modulated radiotherapy with tailored PTV expansion based on inter-fractional CTV displacement had dosimetrical advantages over those with PTV_0.5 or those with PTV_0.7 owing to its perfect PTV dose coverage and better OARs sparing(especially of heart and left lung).

CONCLUSION

The CTV displacement in PMRM-IMRT predominantly arises from inter-fraction rather than from intra-fraction during natural respiration and differs in 3 coordinate axes either inter-fractionally or intra-fractionally. Tailoring and minimizing PTV expansion three-dimensionally significantly improves the dosimetry of PMRM-IMRT for left-sided breast cancer patients.

Short-Term Outcomes of Transcatheter Versus Isolated Surgical Aortic Valve Replacement for Mediastinal Radiation-Associated Severe Aortic Stenosis

BACKGROUND

Surgical aortic valve replacement (SAVR) is associated with adverse outcomes in patients with radiation-associated aortic stenosis. Transcatheter aortic valve replacement (TAVR) may improve outcomes in this population.

METHODS

We evaluated 1668 TAVR and 2611 patients with SAVR enrolled in the Society of Thoracic Surgeons' database between 2011 and 2018. Multiple logistic regression was used to compare 30- day outcomes between TAVR and SAVR. Propensity-matched analysis was performed to confirm results of the overall cohort. Additionally, the cohort was stratified into early (2011-2014) versus contemporary (2015-2018) TAVR eras, and 30-day outcomes for TAVR and SAVR were compared. Finally, outcomes with transfemoral TAVR versus SAVR were compared.

RESULTS

In the overall cohort, TAVR was associated with significantly reduced 30-day mortality (odds ratio [OR]_TAVR/SAVR=0.60 [0.40-0.91]). Postoperative atrial fibrillation, pneumonia, pleural effusion, renal failure, and bleeding also occurred less frequently with TAVR. Stroke/transient ischemic attack (TIA; OR_TAVR/SAVR, 2.03 [1.09-3.77]) and pacemaker implantation (OR_TAVR/SAVR, 1.62 [1.21-2.17]) were higher with TAVR. Propensity-matched analysis yielded similar results as the overall cohort. Following stratification by era, TAVR versus SAVR was associated with reduced 30-day mortality in the contemporary but not early era (OR_Early, 0.78 [0.48-1.28]; OR_Contemporary, 0.31 [0.14-0.65]). Pacemaker implantation was higher with TAVR versus SAVR in both eras (OR_Early, 1.60 [1.03-2.46]; OR_Contemporary, 1.64 [1.10-2.45]). There was also a nonsignificant trend towards increased stroke/TIA with TAVR during both eras (OR_Early, 1.39 [0.58-3.36]; OR_Contemporary, 2.46 [0.99-6.10]). Finally, transfemoral TAVR (N=1369) versus SAVR revealed similar findings as the overall cohort; however, the association of TAVR with stroke/TIA was not statistically significant (OR_Stroke/TIA, 1.57 [0.79-3.09]).

CONCLUSIONS

TAVR provides an effective and evolving alternative to SAVR for radiation-associated severe aortic stenosis and was associated with lower 30-day mortality and postoperative complications. TAVR was associated with increased pacemaker implantation and a trend towards increased stroke/TIA. In this unique population with extensive valvular and vascular calcifications, the risk of stroke/TIA with TAVR requires careful consideration and further investigation.