Cardiovascular sequelae of therapeutic thoracic radiation

Outcomes of transcatheter aortic valve replacement in patients with history of chest wall irradiation: Propensity matched analysis of five years data from national inpatient sample (2016-2020)

INTRODUCTION

Chest radiotherapy has been utilized to treat intra-thoracic and mediastinal tumors. Chest wall irradiation (C-XRT) survivors frequently develop valvular disease, including aortic stenosis, which eventually requires valve replacement. Previous trials have shown worse outcomes with surgical aortic valve replacement. However, transcatheter aortic valve replacement (TAVR) outcomes-related data in patients with C-XRT is limited.

METHODS

The national inpatient sample (NIS) database was queried from 2016 to 2020 to identify adult hospitalizations with TAVR, which were dichotomized based on a history of C-XRT using ICD-10-CM codes. Propensity score matching was performed to derive age, sex, hospital characteristics, and co-morbidities matched controls without a history of C-XRT. The outcomes studied were inpatient mortality and complications, mean length of stay (LOS), and total hospital charge (THC). Multivariate logistic and linear regression were used to analyze the outcomes.

RESULTS

Of 296,670 patients who underwent TAVR between 2016 and 2020, 515 had a history of C-XRT. Upon propensity score matching in patients undergoing TAVR, Patients with a history of C-XRT showed significantly lower adjusted odds of in-hospital mortality (adjusted odd ratio [aOR] 0.04, 95 % CI [0.003-0.57], p = 0.017), lower mean LOS by 1.6 days (-1.88 to -1.26 days, p < 0.001) and reduced mean THC (-$74,720, [-$88,784 to -$60,655], p < 0.001). Additionally, patients with C-XRT had significantly lower adjusted odds of inpatient complications, mainly acute myocardial infarction, cerebrovascular events, acute respiratory failure, acute kidney injury, need for vasopressors and cardiopulmonary resuscitation, whereas similar odds of complications, including a requirement of intubation, mechanical ventilation, hemodialysis, and cardiogenic shock.

CONCLUSION

Our analysis showed reduced adjusted odds of in-hospital mortality, length of stay, total hospital charges, and inpatient complications in patients undergoing TAVR with a history of C-XRT. TAVR appears to be a safe and viable alternative in this population subgroup.

Advances in Screening for Radiation-Associated Cardiotoxicity in Cancer Patients

PURPOSE OF REVIEW

Radiation is foundational to the treatment of cancer and improves overall survival. Yet, it is important to recognize the potential cardiovascular effects of radiation therapy and how to best minimize or manage them. Screening-both through imaging and with biomarkers-can potentially identify cardiovascular effects early, allowing for prompt initiation of treatment to mitigate late effects.

RECENT FINDINGS

Cardiac echocardiography, magnetic resonance imaging (MRI), computed tomography, and measurements of troponin and natriuretic peptides serve as the initial screening tests of choice for RICD. Novel imaging applications, including positron emission tomography and specific MRI parameters, and biomarker testing, including myeloperoxidase, growth differentiation factor 15, galectin 3, micro-RNA, and metabolomics, hold promise for earlier detection and more specific characterization of RICD. Advances in imaging and novel applications of biomarkers have potential to identify subclinical RICD and may reveal opportunities for early intervention. Further research is needed to elucidate optimal imaging screening modalities, biomarkers, and surveillance strategies.

Assessment of hyperbaric oxygenation treatment response in parotid glands by T 2 mapping following radiotherapy for head and neck tumours

Background

The study was designed to evaluate the influence of hyperbaric oxygenation therapy (HBOT) on the parotid gland in patients following radiotherapy for head and neck tumours.

Patients and methods

HBOT response was monitored by 3T magnetic resonance imaging (MRI) using T₂ mapping and subsequent measurement of mean T₂ and T₂ variability as well as by salivary tests (salivary flow, buffer capacity, and pH). Eighteen patients previously treated with irradiation doses between 50 and 80 Gy as well as 18 healthy gender and age matched controls were enrolled. MRI was performed prior to HBOT (40.2 ± 20 months after radiotherapy) and after 20 daily HBOT at 2.5 ATA (absolute atmosphere). Each HBOT consisted of breathing 100% oxygen for 90 minutes.

Results

Significant differences in mean T₂ prior to HBOT were observed between the ipsilateral irradiated (121 ± 20 ms), contralateral parotids (107 ± 21) and control group (96 ± 12 ms). A positive correlation in patients between T₂ variability and irradiation dose was detected in contralateral parotids before HBOT (R = 0.489, p = 0.0287). In addition, negative correlations were observed between mean T₂ in the ipsilateral as well as the contralateral gland and salivary flow before and after HBOT. Negative correlations between mean T₂, T₂ variability and pH of unstimulated saliva were also observed in the sides of parotid before and after HBOT.

Conclusions

The study confirmed that T₂ mapping had a potential for monitoring the differences between irradiated and normal parotid glands. It could also be useful in the assessment of the glandular tissue response to HBOT.

Radiation-Associated Pericardial Disease

PURPOSE OF REVIEW

This review highlights the literature related to pericardial injury following radiation for oncologic diseases.

RECENT FINDINGS

Radiation-associated pericardial disease can have devastating consequences. Unfortunately, there is considerably less evidence regarding pericardial syndromes following thoracic radiation as compared to other cardiovascular outcomes. Pericardial complications of radiation may arise acutely or have an insidious onset several decades after treatment. Transthoracic echocardiography is the screening imaging modality of choice, while cardiac magnetic resonance imaging further characterizes the pericardium and guides treatment decision-making. Cardiac CT can be useful for assessing pericardial calcification. Ongoing efforts to lessen inadvertent cardiac injury are directed towards the revision of radiation techniques and protocols. As survival of mediastinal and thoracic malignancies continues to improve, radiation-associated pericardial disease is increasingly relevant. Though advances in radiation oncology demonstrate promise in curtailing cardiotoxicity, the long-term effects pertaining to pericardial complications remain to be seen.

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

PURPOSE OF REVIEW

Radiation-associated cardiac disease (RACD) is an increasingly recognized latent manifestation of chest and mediastinal radiation therapy. The delayed presentation reflects increased survival rates from malignancies successfully treated decades previously. However, individuals are now presenting with multiple coexistent manifestations of RACD and pulmonary disease as a consequence of high-dose radiation administered prior to the routine institution of modern dose-modulating regimens. Increased awareness of RACD is critical for implementation of appropriate screening algorithms and for specific management strategies involving the timing and strategies of intervention in these patients.

RECENT FINDINGS

Recent advances in multimodality cardiac imaging have demonstrated pathognomonic findings of RACD, which can predict outcomes including mortality. Accurate diagnosis of these typically concurrent manifestations is critical and should prompt referral to a center experienced in managing RACD as surgical risk is significantly increased for this patient cohort, particularly for those undergoing redo operation. The latent effect of RACD and its unique combination of manifestations means that these patients will increasingly present with challenging management issues, resulting in increased rates of morbidity and mortality. Timing of treatment intervention must be carefully considered, although percutaneous options may provide alternative future strategies for this higher risk cohort.

Radiation-Induced Cardiovascular Disease: A Clinical Perspective

Cancer survival has improved dramatically, and this has led to the manifestation of late side effects of multimodality therapy. Radiation (RT) to the thoracic malignancies results in unintentional irradiation of the cardiac chambers. RT-induced microvascular ischemia leads to disruption of capillary endothelial framework, and injury to differentiated myocytes results in deposition of collagen and fibrosis. Coexistence of risk factors of metabolic syndrome and preexisting atherosclerosis in addition to RT exposure results in accelerated occurrence of major coronary events. Hence, it becomes pertinent to understand the underlying pathophysiology and clinical manifestations of RT-induced cardiovascular disease to devise optimal preventive and surveillance strategies.

Valvular Heart Disease in Cancer Patients: Etiology, Diagnosis, and Management

OPINION STATEMENT

Cardiac valvular disease as consequence of radiation and chemotherapy during treatment for malignancy is growing in its awareness. While the overwhelming emphasis in this population has been on the monitoring and preservation of left ventricular systolic function, we are now developing a greater appreciation for the plethora of cardiac sequelae beyond this basic model. To this end many institutions across the country have developed cardio-oncology programs, which are collaborative practices between oncologists and cardiologists in order to minimize a patient's cardiovascular risk while allowing them to receive the necessary treatment for their cancer. These programs also help to recognize early nuanced treatment complications such as valvular heart disease, and provide consultation for the most appropriate course of action. In this article we will discuss the etiology, prevalence, diagnosis, and current treatment options of valvular heart disease as the result of chemotherapy and radiation.

Radiation induced heart disease: Pathogenesis, management and review literature

Radiation therapy (RT) is a very important part of multimodality cancer therapy. Addition of RT improves survival in many cancers, but there are some accompaniments of radiation. One of them is radiation induced heart disease (RIHD). RT for mediastinal lymphoma, breast, lung and oesophageal cancer is associated with the development of RIHD. The problem can be intensified with the addition of chemotherapy. Therapeutic modalities for RIHD are the same as in the non-irradiated population. However, surgery may be difficult in the irradiated patients. The long latent period is the reason why RIHD is not extensively studied. Survival of cancer patients has improved over past few decades, so RIHD is a growing concern especially in younger patients. In this review article, we have discussed the pathogenesis, clinical manifestation and management of RIHD along with impact of chemotherapeutic agents.

Impact of long-axis function on cardiac surgical outcomes in patients with radiation-associated heart disease

BACKGROUND

Malignancy-associated thoracic radiation leads to radiation-associated cardiac disease (RACD) that often necessitates cardiac surgery. Myocardial dysfunction is common in patients with RACD. We sought to determine the predictive value of global left ventricular ejection fraction and long-axis function left ventricular global longitudinal strain (LV-GLS) in such patients.

METHODS

We studied 163 patients (age, 63 ± 14 years; 74% women) who had RACD and underwent cardiac surgery (20% had reoperations) between 2000 and 2003. In addition to standard echocardiography, LV-GLS (%) was derived from the average of 18 segments in 3 apical views of the left ventricle, using velocity vector imaging. Standard clinical and demographic parameters were recorded. All-cause mortality was recorded.

RESULTS

The mean duration between cardiac surgery and the last chest radiation was 18 ± 12 years. The median European System for Cardiac Operative Risk Evaluation (EuroSCORE) was 8, and 88 patients died over 6.6 ± 4 years. A total of 52% of patients had ≥ II+ mitral regurgitation; 23% of patients had severe aortic stenosis; and 39% of patients had ≥ II+ tricuspid regurgitation. The mean left ventricular ejection fraction was 54% ± 13%, and the mean LV-GLS was -12.9% ± 4%. In a Cox proportional survival analysis, lower LV-GLS was predictive of mortality in univariable analysis (hazard ratio, 1.07 (95% confidence interval, 1.01-1.14); P = .006); however, after adjustment for other variables, the association became nonsignificant. In patients with a EuroSCORE <median, abnormal LV-GLS (<-14.5%) was associated with significantly higher mortality (48%), compared with those with normal LV-GLS (32%).

CONCLUSIONS

In patients who have RACD and undergo cardiac surgery, LV-GLS does not sufficiently discriminate and is not independently predictive of long-term outcomes. However, in patients with a low EuroSCORE, abnormal LV-GLS was associated with higher mortality, compared with those with normal LV-GLS.

Long-term survival of patients with radiation heart disease undergoing cardiac surgery: a cohort study

BACKGROUND

Thoracic radiation results in radiation-associated heart disease (RAHD), often requiring cardiothoracic surgery (CTS). We sought to measure long-term survival in RAHD patients undergoing CTS, to compare them with a matched control population undergoing similar surgical procedures, and to identify potential predictors of long-term survival.

METHODS AND RESULTS

In this retrospective observational cohort study of patients undergoing CTS, matched on the basis of age, sex, and type/time of CTS, 173 RAHD patients (75% women; age, 63±14 years) and 305 comparison patients (74% women; age, 63±4 years) were included. The vast majority of RAHD patients had prior breast cancer (53%) and Hodgkin lymphoma (27%), and the mean time from radiation was 18±12 years. Clinical and surgical parameters were recorded. The preoperative EuroSCORE and all-cause mortality were recorded. The mean EuroSCOREs were similar in the RAHD and comparison groups (7.8±3 versus 7.4±3, respectively; P=0.1). Proximal coronary artery disease was higher in patients with RAHD versus the comparison patients (45% versus 38%; P=0.09), whereas redo CTS was lower in the RACD versus the comparison group (20% versus 29%; P=0.02). About two thirds of patients in either group had combination surgical procedures. During a mean follow-up of 7.6±3 years, a significantly higher proportion of patients died in the RAHD group than in the comparison group (55% versus 28%; P<0.001). On multivariable Cox proportional hazard analysis, RAHD (2.47; 95% confidence interval, 1.82-3.36), increasing EuroSCORE (1.22; 95% confidence interval, 1.16-1.29), and lack of β-blockers (0.66; 95% confidence interval, 0.47-0.93) were associated with increased mortality (all P<0.01).

CONCLUSIONS

In patients undergoing CTS, RAHD portends increased long-term mortality. Alternative treatment strategies may be required in RAHD to improve long-term survival.

Cardiac complications after radical radiotherapy

Improvements in cancer therapy have led to increasing numbers of cancer survivors, and the long-term complications of these treatments are now becoming apparent. This article presents the current knowledge of adverse cardiovascular effects of radiotherapy to the chest. Medline literature searches relating to the cardiac complications of radiotherapy and subsequent prognosis were conducted. Potential adverse effects of mediastinal irradiation are numerous and can include coronary artery disease, pericarditis, cardiomyopathy, and valvular disease. Damage seems to be related to radiation dose, volume of irradiated heart, age at exposure, technique of chest irradiation, and patient-specific factors. The advent of technology and the newer sophisticated techniques in treatment planning and delivery are expected to decrease the incidence of cardiovascular diseases after radiation of the mediastinal structures. In any case, patients subjected to irradiation of the mediastinal structures require close multidisciplinary clinical monitoring.

The effects of proton radiation on the prothrombin and partial thromboplastin times of irradiated ferrets

PURPOSE

To determine whether proton radiation affects coagulation.

MATERIAL AND METHODS

Ferrets were exposed to solar particle event-like proton radiation at doses of 0, 25, 100, or 200 centigray (cGy), and dose rates of 50 cGy/minute (high dose rate or HDR) or 50 cGy/hour (low dose rate or LDR). Plasma was isolated from blood collected prior to radiation exposure and at 3-7 h post-radiation. Prothrombin time (PT) assays and activated partial thromboplastin time (aPTT) assays were performed as were mixing studies to determine the coagulation factors involved.

RESULTS

HDR and LDR exposure led to statistically significant increases in PT values. It was determined that the HDR-induced increase in PT was due to Factor VII, while Factors II, V, and VII contributed to the LDR-induced increase in PT values. Only acute LDR exposure caused an increase in aPTT values, which remained elevated for 48 h post-irradiation (which was the latest time assayed in these studies). Mixing studies revealed that Factor IX contributed to the increased aPTT values. A majority of the animals exposed at the LDR had an International Normalized Ratio approaching or surpassing 2.0.

CONCLUSIONS

PT/aPTT assays resulted in increased clotting times due to different coagulation factors, indicating potential radiation-induced coagulopathy.

Long-term cardiac and pulmonary complications of cancer therapy

Cardiac complications resulting from chemotherapy and radiation pose a significant risk for morbidity and mortality to the cancer survivor. Cardiac side effects may progress over time and are a concern for patients treated during childhood. Long-term pulmonary complications are relatively infrequent, and acute respiratory effects of drugs (mostly bleomycin) or radiation normally resolve early after therapy. Although most cardiovascular risk statistics and clinical experience are derived from patients treated before 1985, the modern radiation approach that limits the exposure of the heart and reduces the total dose seems to attenuate the previously observed cardiovascular risk. Potential preventive measures for high-risk patients are of increasing interest but remain experimental.

The effect of hyperbaric oxygenation on postradiation xerostomia and saliva in patients with head and neck tumours

The study was designed to evaluate the influence of hyperbaric oxygenation (HBO) therapy on salivary gland function and the growth of salivary Streptococcus mutans, Lactobacillus and Candida albicans in patients with head and neck tumours who had undergone radiation therapy. Sixteen patients were included, with radiation doses from 58 to 70 Gy. The first examination was performed at baseline before the first HBO therapy (33.7 ± 9 months after radiation therapy), and the second after 20 daily HBO therapies in a hyperbaric chamber at 2.5 ATA (absolute atmospheres), where patients breathed 100% oxygen for 90 min each day. Measurements of salivary flow, buffer capacity, saliva pH and colony density of S. mutans, Lactobacillus and C. albicans in stimulated saliva were conducted, and xerostomia grade was assessed. Salivary flow increased from 0.20 ± 0.1 to 0.39 ± 0.2 ml/min at the end of HBO therapy (p < 0.001). Salivary pH also increased from 6.0 ± 0.2 to 6.5 ± 0.1 (p < 0.05). The colony density decreased from the time at baseline to the end of HBO therapy for S. mutans (p < 0.001), Lactobacillus (p < 0.05) and the fungus C. albicans (p < 0.05). The xerostomia grade decreased from 2.63 ± 0.2 to 1.94 ± 0.2 after HBO (p < 0.001). There was no significant change in buffer capacity. The increased salivary secretion rate and salivary pH, and decreased S. mutans and Lactobacillus colony density that were observed after HBO therapy may reduce caries progression in those patients.

Antiemetic care for patients with breast cancer: focus on drug interactions and safety concerns

PURPOSE

The drug interactions and adverse events that should be considered when individualizing antiemetic therapy for patients undergoing treatment for breast cancer are reviewed.

SUMMARY

A variety of antiemetic agents are available, including antihistamines, dopamine-receptor antagonists, serotonin-receptor antagonists, and neurokinin-receptor antagonists. To ensure optimal symptom control for each patient without unnecessarily prolonging treatment, patient- and treatment-specific risk factors must be considered. Neurokinin-receptor antagonists, the newest class of antiemetics, are effective in preventing acute and delayed chemotherapy-induced nausea and vomiting but must be used in combination with a serotonin-receptor antagonist and a corticosteroid. The serotonin-receptor antagonists have become the mainstay of antiemetic therapy, but current guidelines do not distinguish among the different agents in this class. However, there are distinct pharmacologic differences that may affect the potential for drug interactions and, ultimately, patient outcomes and the occurrence of adverse events. Therefore, the potential for drug interactions must be considered when selecting an antiemetic, particularly for patients who are taking multiple concomitant medications. Further, because a number of breast cancer therapies and some antiemetic agents carry cardiovascular warnings or precautions and since breast cancer patients may already be suffering from cardiovascular complications, the possible cardiotoxic effects of the antiemetic or chemotherapy agents or the combinations of these agents should be considered.

CONCLUSION

Antiemetic treatment is essential for patients with breast cancer who are undergoing moderately to highly emetogenic cytotoxic treatment. When selecting an antiemetic, clinicians must select an agent that provides optimal protection against nausea and vomiting while avoiding drug-drug interactions and additional adverse events.

Altered left ventricular diastolic performance in oncologic patients treated with epirubicin

Anthracyclines confer an increased risk of cardiotoxicity. The authors evaluated left ventricular (LV) performance in patients treated with epirubicin. Sixty-eight patients with malignancies (study group), treated with epirubicin < or = 450 mg/m2, and a matched control group of 68 cancer patients who had not started chemotherapy were evaluated by Doppler echocardiography. The authors assessed LV diastolic function by measuring the transmitral flow: the maximal velocity of the E and A waves, the Emax/Amax ratio, the pressure half time of E wave (PHT), and the isovolumic relaxation time (IVRT). Global LV ejection fraction (LVEF) was estimated to determine the systolic performance. The authors documented alterations of the LV diastolic performance in the study group by finding a significant decrease in Emax, whereas Amax was significantly increased. Prolonged PHT and IVRT were also certified in the epirubicin-treated group compared with controls. No significant variation in LVEF between the 2 groups was detected.

Late Drug-eluting Stent Thrombosis and Erythropoietin: Cause and Effect?

A case of late thrombosis of a sirolimus-eluting stent, 16 months after implantation, is described. Two weeks prior to presentation with stent thrombosis the patient had a 50% dose increase of longterm erythropoietin. The prothrombotic effect of erythropoietin may have precipitated the thrombotic event.

Cardiac surgery after mediastinal radiation: extent of exposure influences outcome

OBJECTIVES

Mediastinal radiation for thoracic malignancies uses multiple treatment fields and doses. We investigated whether more extensive radiation exposure is associated with more hospital complications and worse survival after cardiac surgery.

METHODS

From January 2000 to January 2005, 230 patients underwent cardiac surgery after 3 levels of mediastinal radiation: extensive (Hodgkin disease, thymoma, and testicular cancer; n = 70), variable (eg, non-Hodgkin lymphoma and lung cancer; n = 35); and tangential (breast cancer; n = 125). Hospital complications were recorded prospectively, and time-related survival was assessed by patient follow-up (mean follow-up, 2.2 +/- 1.4 years).

RESULTS

Patients receiving extensive exposure were youngest (51 vs 64 vs 72 years), with the longest radiation-to-operation interval (25 vs 13 vs 14 years), and had the most diastolic dysfunction, left main stenosis of greater than 70% (21% vs 9% vs 8%), and aortic regurgitation (79% vs 54% vs 50%). Patients receiving extensive and variable exposure had the poorest pulmonary function (percent predicted forced expiratory volume in 1 second, 57% vs 54% vs 67%; percent predicted forced vital capacity, 56% vs 63% vs 66%). All groups received a similar mix of cardiac procedures. Hospital deaths (13% vs 8.6% vs 2.4%) and respiratory complications (24% vs 20% vs 9.6%) were higher after more extensive radiation, and survival was poorer (4-year survival, 64% vs 57% vs 80%) than for patients receiving tangential radiation exposure, and it deviated more from expected matched-population life tables.

CONCLUSIONS

Among patients undergoing cardiac surgery after thoracic radiation, radiation exposure is heterogeneous, and therefore these patients cannot be managed and assessed as a single uniform cohort. Extensively irradiated patients are more likely to develop radiation heart disease, which increases perioperative morbidity and decreases short- and long-term survival.

Surviving childhood cancer: the impact on life

With modern therapies, most children diagnosed with cancer are expected to reach adulthood. Therefore, there are large and ever-increasing numbers of children and young adults in our population who are survivors of childhood cancer. Many of the therapies responsible for improved cancer survival rates can also damage normal cells and tissues. As more children survive cancer, the physical and emotional costs of enduring cancer therapy become increasingly important. Although most childhood cancer survivors are now expected to survive, they remain at risk for relapse, second malignant neoplasms, organ dysfunction, and a negative psychologic impact. Individual risk is quite variable and is dependent on multiple factors including the type and site of cancer, the therapy utilized, and the individual's constitution. The risks are likely to change as we learn more about the specific long-term effects of cancer therapy, develop more refined and targeted therapies, and develop and apply more effective preventative strategies or therapeutic interventions. Guidelines for long-term follow-up have been established and are available to help facilitate appropriate monitoring of and care for potential late effects.

Cardiac complications of radiation therapy

AIMS

To present an overview of cardiac complications arising from radiation therapy.

MATERIALS AND METHODS

Medline the (February 2004) and Embase (1974 to February 2004) searches of the medical literature relating to the cardiac complications of radiotherapy were conducted.

RESULTS

Radiation damage may affect the pericardium, myocardium or coronary vasculature, and consists of fibrotic or small vessel damage. Cardiac complications are a particular problem with radiation treatments to the mediastinum and breast, especially when greater than 65% of the heart is irradiated. Most of the literature relates to the treatment of Hodgkin's disease, as patients with this disease tend to be young and live long enough to manifest late cardiac complications. Pericarditis, angina, myocardial infarction and arrhythmias are the most frequent causes of morbidity, with myocardial infarction being the most common fatal complication. The incidence of ischaemic heart disease does not increase rapidly until 10 years from treatment.

CONCLUSIONS

Much of the evidence relates to the use of outdated radiation therapy equipment and techniques. Today's patients almost certainly have a lower risk of cardiac complications. Cardiac complications are probably under-reported, as they occur long after cured patients have been discharged from follow-up.

Cardiovascular effects of radiation therapy: practical approach to radiation therapy-induced heart disease

Radiation induced heart diseases (RIHD) are increasingly recognized as more patients who received radiation therapy survive their diseases with improved management of various malignancies. Radiation affects every component of the heart, ranging from subclinical histopathologic changes to overt clinical disease. Pericardial involvement is the most common and includes asymptomatic pericardial effusion and constrictive pericarditis. The diseases involving the myocardium, valvular apparatus, and conduction system are often subclinical. When symptomatic, they are often the harbinger of more lethal, but treatable, radiation-induced coronary artery disease (CAD). Improvements in the modern radiation delivery systems have minimized irradiation of the heart. However, with increased and emerging indications for radiation therapy for various malignancies in the chest, as a part of bone marrow transplantations, and as the main agent of brachytherapy for advanced preexisting CAD, the incidence of RIHD is likely to increase. Appropriate management of RIHD, either overt or occult, must include understanding the natural history of RIHD, recognition of symptoms by careful history, and vigilant search for treatable causes of the RIHD or other diseases that might mimic RIHD. This article focuses on providing practical yet comprehensive clinical information for general internal medicine and cardiology practices.

Pathology of radiation and anthracycline cardiotoxicity

Radiation-induced heart disease (RIHD) and anthracycline cardiotoxicity are two patterns of cardiac dysfunction caused by therapeutic interventions to treat malignancies. They occur in both the pediatric and adult populations and there is evidence to suggest that pediatric patients are at greater risk. This is due in part to the longer survival rates but also reflects increased susceptibility to the attendant complications caused by both therapies. Radiation can cause injury to all the components of the heart, including the vasculature, while anthracycline toxicity is generally limited to the myocardium.

Cardiac safety of trastuzumab in combination with epirubicin and cyclophosphamide in women with metastatic breast cancer

This prospective, parallel-group, dose-escalation study evaluated the cardiac safety of trastuzumab (Herceptin) plus epirubicin/cyclophosphamide (EC) in women with human epidermal growth factor receptor-2 (HER2)-positive metastatic breast cancer (MBC) and determined an epirubicin dose for further evaluation. HER2-positive patients received standard-dose trastuzumab plus epirubicin (60 or 90 mg/m(2))/cyclophosphamide (600 mg/m(2)) 3-weekly (EC60+H, n=26; EC90+H, n=25), for four to six cycles; 23 HER2-negative patients received EC alone (90/600 mg/m(2)) 3-weekly for six cycles (EC90). All patients underwent thorough cardiac evaluation. Two EC90+H-treated patients experienced symptomatic congestive heart failure 4.5 and 6 months after the end of chemotherapy. One EC60+H-treated patient experienced an asymptomatic decrease in left ventricular ejection fraction (LVEF) to <50% 6 months after the end of chemotherapy. No such events occurred in control patients. Asymptomatic LVEF decreases of >10% points were detected in 12 (48%), 14 (56%) and 5 (24%) patients treated with EC60+H, EC90+H, and EC90. Objective response rates with EC60+H and EC90+H were >60%, and 26% for EC90 alone. These results indicate that trastuzumab may be combined with EC with manageable cardiotoxicity and promising efficacy.

Radiation-associated cardiovascular disease

As the number of cancer survivors grows because of advances in therapy, it has become more important to understand the long-term complications of these treatments. This article presents the current knowledge of adverse cardiovascular effects of radiotherapy to the chest. Emphasis is on clinical presentations, recommendations for follow-up, and treatment of patients previously exposed to irradiation. Medline literature searches were performed, and abstracts related to this topic from oncology and cardiology meetings were reviewed. Potential adverse effects of mediastinal irradiation are numerous and can include coronary artery disease, pericarditis, cardiomyopathy, valvular disease and conduction abnormalities. Damage appears to be related to dose, volume and technique of chest irradiation. Effects may initially present as subclinical abnormalities on screening tests or as catastrophic clinical events. Estimates of relative risk of fatal cardiovascular events after mediastinal irradiation for Hodgkin's disease ranges between 2.2 and 7.2 and after irradiation for left-sided breast cancer from 1.0 to 2.2. Risk is life long, and absolute risk appears to increase with length of time since exposure. Radiation-associated cardiovascular toxicity may in fact be progressive. Long-term cardiac follow-up of these patients is therefore essential, and the range of appropriate cardiac screening is discussed, although no specific, evidence-based screening regimen was found in the literature.

Pathophysiological effects of radiation on atherosclerosis development and progression, and the incidence of cardiovascular complications

Radiation therapy while important in the management of several diseases, is implicated in the causation of atherosclerosis and other cardiovascular complications. Cancer and atherosclerosis go through the same stages of initiation, promotion, and complication, beginning with a mutation in a single cell. Clinical observations before the 1960s lead to the belief that the heart is relatively resistant to the doses of radiation used in radiotherapy. Subsequently, it was discovered that the heart is sensitive to radiation and many cardiac structures may be damaged by radiation exposure. A significantly higher risk of death due to ischemic heart disease has been reported for patients treated with radiation for Hodgkin's disease and breast cancer. Certain cytokines and growth factors, such as TGF-beta1 and IL-1 beta, may stimulate radiation-induced endothelial proliferation, fibroblast proliferation, collagen deposition, and fibrosis leading to advanced lesions of atherosclerosis. The treatment for radiation-induced ischemic heart disease includes conventional pharmacological therapy, balloon angioplasty, and bypass surgery. Endovascular irradiation has been shown to be effective in reducing restenosis-like response to balloon-catheter injury in animal models. Caution must be exercised when radiation therapy is combined with doxorubicin because there appears to be a synergistic toxic effect on the myocardium. Damage to endothelial cells is a central event in the pathogenesis of damage to the coronary arteries. Certain growth factors that interfere with the apoptotic pathway may provide new therapeutic strategies for reducing the risk of radiation-induced damage to the heart. Exposure to low level occupational or environmental radiation appears to pose no undue risk of atherosclerosis development or cardiovascular mortality. But, other radiation-induced processes such as the bystander effects, abscopal effects, hormesis, and individual variations in radiosensitivity may be important in certain circumstances.

Pathophysiology of one-lung ventilation

The management of some problematic patients having thoracic surgery is among the most difficult challenges for the anesthesiologist. Increasingly complex operations are performed on seriously compromised patients because of the development of new surgical techniques and the anesthesiologists' awareness of surgical needs and requirements to provide a satisfactory and safe surgical field. In order to facilitate thoracic surgery, the single most important and valuable anesthetic technique used actually is one-lung ventilation. This article reviews the complex pathopysiology of one-lung ventilation.

Prognostic role of pericardial fluid cytology in cardiac tamponade associated with non-small cell lung cancer

BACKGROUND AND STUDY OBJECTIVES

Cardiac tamponade is a life-threatening complication of non-small cell lung cancer (NSCLC). Malignant pericardial effusion signifies advanced disease, but the significance of a negative pericardial fluid cytology in patients with advanced lung cancer is still controversial. The differential diagnosis of cytology-negative pericardial effusion is difficult and sometimes impossible. The purpose of this study is to determine the prognostic role of pericardial fluid cytology in patients with NSCLC and cardiac tamponade.

DESIGN

Retrospective review of patients with concurrent NSCLC and cardiac tamponade over a 10-year period.

METHODS AND RESULTS

Eighty-two patients were included in this study. Pericardial fluid cytology was positive in 60 patients and negative in 22 patients. The overall median survival was 74.5 days, and 1-year survival was 7.3%, with no survival difference between the two groups (p = 0.2506). However, there was a significant survival difference after different treatment strategies. Patients receiving systemic chemotherapy survived longer than those receiving local therapy (p<0.001), and these patients, in turn, survived longer than those receiving supportive treatment (p<0.001).

CONCLUSIONS

When patients have concurrent advanced NSCLC and cardiac tamponade, the most likely cause of the pericardial effusion is the cancer itself, regardless of the results of the cytologic examination. Our results suggest that systemic chemotherapy might prolong survival in such patients, but further prospective, randomized study is necessary.

Brady-tachycardia syndrome after radiotherapy for lung cancer. Assessment by computed tomography and carbon-11 methionine positron emission tomography

A 74-year-old male who had received radiotherapy (total 54 Gy) for right lung cancer 7 months earlier developed a symptomatic brady-tachycardia syndrome requiring the implantation of a permanent pacemaker. Chest CT showed a pulmonary tumor of 2-cm diameter in the right lower lobe with direct extension into the surrounding tissue, suggesting the possibility of cardiac invasion. Carbon-11 methionine positron emission tomography (PET) indicated the absence of visible invasion of the heart with lung cancer. The bradytachycardia syndrome, therefore, was considered to be associated with sinus node injury due to radiation. Carbon-11 methionine PET metabolic imaging might play an important role in evaluating noninvasively the cause of the arrhythmia in this patient.

[Heart pathology of extracardiac origin. VII. Heart and neoplasms]

Cardiac alterations of neoplastic diseases can be due to direct invasion produced by primary cardiac tumors or more frequently secondary to local compression of vascular structures by extracardiac neoplasms, such as superior vena cava syndrome. One of the most important alterations is the cardiotoxicity of anticancer treatments, either chemotherapy drugs or radiotherapy techniques. These treatments cause acute and/or chronic cardiotoxicity that the oncologist and the cardiologist must be aware of. For instance, 4.5% to 7% of patients that have been treated with anthracyclines may suffer cardiac failure in their lifetime. The pathogenesis is still not clear. There is currently a lot of research on cardioprotectors, but nowadays the only one approved by the FDA is dexrazoxane, which is used on breast cancer patients treated with adriamycin.

Immediate side effects of large fraction radiotherapy

The use of hypofractionated radiotherapy regimens is becoming more widely recognized in the palliation of non-small cell lung carcinoma (NSCLC). Anecdotal reports of chest pain, rigors and fevers in the hours that follow radiotherapy led us to perform a survey estimating the frequency and severity of these symptoms following treatment to the thorax. One hundred and eighteen patients completed questionnaires 24 hours after palliative radiotherapy treatment; 84 were male. The median age was 67 years. One hundred and seven had histologically confirmed NSCLC. A parallel opposed technique was used in 113 patients. Doses ranged from 8 Gy in a single fraction to 60 Gy in 30 fractions. Chest pain was reported by 54 (45.8%) patients after the first radiotherapy fraction; in 42 it commenced within 12 hours of treatment. The pain varied in site, nature and duration; on 23 occasions, it lasted under 2 hours. Systemic symptoms (rigors, sweating, fevers) were documented on 43 questionnaires, starting within 12 hours of treatment in 33 patients and on 30 occasions lasting less than 2 hours. Chest pain and systemic symptoms occurred together in 28 patients. Only 49 (41.5%) patients reported no immediate side effects. We conclude that patients receiving palliative radiotherapy for bronchial carcinoma often develop significant symptoms in the hours following treatment. The timing and duration suggest a relationship with the radiotherapy, and we feel that patients should be warned of the possible occurrence of these symptoms.