Radiation therapy-induced cardiac injury

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.

Constrictive Pericarditis 5 Months after Radiation Therapy in a 62-Year-Old Woman with Esophageal Cancer

Most pericardial changes appear within a few weeks in patients who have undergone radiation therapy for thoracic neoplasms. Chronic pericardial constriction typically occurs decades later, consequent to fibrosis. Early constrictive pericarditis after chest irradiation is quite rare. We report the case of a 62-year-old woman who underwent radiation therapy for esophageal cancer and presented with constrictive pericarditis 5 months later. We searched the English-language medical literature from January 1986 through December 2015 for reports of early constrictive pericarditis after irradiation for thoracic malignancies. We defined "early" as a diagnosis within one year after radiation therapy. Five cases fit our criteria, and we summarize the findings here. To our knowledge, ours is the first definitive report of a patient with esophageal cancer to present with early radiation-induced constrictive pericarditis. We conclude that constrictive pericarditis can occur early after radiation for thoracic malignancies, albeit rarely. When planning care for cancer patients, awareness of this sequela is helpful.

The risk of reoperative cardiac surgery in radiation-induced valvular disease

OBJECTIVE

Mediastinal radiation therapy (MRT) increases the risk for adverse outcomes after cardiac surgery and is not incorporated in the Society of Thoracic Surgeons (STS) risk algorithm. We aimed to quantify the surgical risk conferred by MRT in patients undergoing primary and reoperative valvular operations.

METHODS

A retrospective analysis of 261 consecutive patients with prior MRT who underwent valvular operations between January 2002 and May 2015. Short- and long-term outcomes were compared for STS predicted risk of mortality, surgery type, gender, year of surgery, and age-matched patients stratified by reoperative status.

RESULTS

Mean age was 62.6 ± 12.1 years and 174 (67%) were women. The majority had received MRT for Hodgkin lymphoma (48.2%) and breast cancer (36%). Overall, 214 (82%) were primary and 47 (18%) were reoperative procedures. Reoperation carried a higher operative mortality than primary cases (17% vs 3.7%; P = .003). Compared with the 836 nonradiated matches, operative mortality and observed-to-expected STS mortality ratios were higher in primary (3.8% [1.4] vs 0.8% [0.32]; P = .004) and reoperative (17% [3.35] vs 2.3% [0.45]; P = .001) patients with prior MRT. Cox proportional hazard modeling revealed that in patients with previous MRT, primary (hazard ratio, 2.24; 95% confidence interval, 1.73-2.91) and reoperative status (hazard ratio, 3.19; 95% confidence interval, 1.95-5.21) adversely affected long-term survival compared with nonradiated matches.

CONCLUSIONS

Surgery for radiation-induced valvular heart disease has a higher operative mortality than predicted by STS predicted risk of mortality. Reoperations are associated with increased morbidity and mortality compared with primary cases. Careful patient selection is paramount and expanded indications for transcatheter therapies should be considered, especially in reoperative patients.

Cardiac transplantation for radiation-induced cardiomyopathy: the Mayo Clinic experience

BACKGROUND

High-dose radiotherapy to the mediastinum for the treatment of malignancies causes injury to the intrathoracic organs. Coronary artery disease, valvular dysfunction, cardiomyopathy, and chronic constrictive pericarditis are common cardiovascular sequelae during long-term follow-up. Cardiac transplantation is indicated for the surgical treatment of heart failure due to radiation-induced end-stage cardiac disease.

METHODS

A retrospective study of radiation-induced cardiomyopathy requiring cardiac transplantation was undertaken from December 1992 to August 2010.

RESULTS

Twelve patients (7 men, 5 women), with a mean age of 47.4 years, underwent orthotopic cardiac transplantation. Redo cardiac operations were performed in 9 patients. Lymphoma was the primary malignancy in all patients. Adjuvant chemotherapy was used in 9 patients, and splenectomy was performed in 7. Restrictive cardiomyopathy (n = 8) was the predominant diagnosis. Restrictive lung disease was present in 10 patients (83%). Postoperative chronic kidney injury developed in 3 patients (25%). Hospital mortality was 8.3%. Survival at 1, 5, and 10 years was 91.7%, 75%, and 46.7%, respectively. The overall mean follow-up was 7.7 years (median, 6.1; range, 1.8 to 16.4 years). Late respiratory failure accounted for 3 deaths.

CONCLUSIONS

Cardiac transplantation provides satisfactory medium-term to long-term outcome in patients with radiation-induced cardiomyopathy. Secondary malignancies, kidney injury, and respiratory failure contribute to significant postoperative morbidity and death.

Outcome of allogeneic hematopoietic stem cell transplantation in patients with low left ventricular ejection fraction

A high risk of regimen-related toxicity with allogeneic hematopoietic stem cell transplantation (allo-HSCT) limits this potentially curative treatment for patients with a left ventricular ejection fraction (LVEF) of > or =50%. We evaluated the frequency of cardiac complications and 100-day nonrelapse mortality (NRM) in 56 patients with a LVEF of < or =45%, who received allo HCT at our institution. The results were retrospectively compared with a matched control group with LVEF of > or =50%, which received an allogeneic stem cell transplantation (allo-SCT). After a median follow-up of 29 months in the study group, grade > or =2 cardiac complications were seen in 7 of 56 (12.5%) patients and cumulative incidence of 100-day NRM was 12.5% with no deaths from cardiac causes. In contrast, after a median follow-up of 49 months in the control group, grade >2 cardiac complications were seen in 19 of 161 patients (11.8%; P = 1.00) and cumulative incidence of 100-day NRM was 14.9% (P = .82). The presence of at least 1 of the 7 pretransplant cardiac risk factors (past history of smoking, hypertension, hyperlipidemia, coronary artery disease, arrhythmia, prior myocardial infarction, and congestive heart failure) was associated with a higher cardiac complication rate in the study group (P = .03). In conclusion, selected patients with a LVEF of < or =45% can safely receive allo-HCT without a significant increase in cardiac toxicity or NRM.

Impact of patient-specific factors, irradiated left ventricular volume, and treatment set-up errors on the development of myocardial perfusion defects after radiation therapy for left-sided breast cancer

PURPOSE

The aim of this study was to assess the impact of patient-specific factors, left ventricle (LV) volume, and treatment set-up errors on the rate of perfusion defects 6 to 60 months post-radiation therapy (RT) in patients receiving tangential RT for left-sided breast cancer.

METHODS AND MATERIALS

Between 1998 and 2005, a total of 153 patients were enrolled onto an institutional review board-approved prospective study and had pre- and serial post-RT (6-60 months) cardiac perfusion scans to assess for perfusion defects. Of the patients, 108 had normal pre-RT perfusion scans and available follow-up data. The impact of patient-specific factors on the rate of perfusion defects was assessed at various time points using univariate and multivariate analysis. The impact of set-up errors on the rate of perfusion defects was also analyzed using a one-tailed Fisher's Exact test.

RESULTS

Consistent with our prior results, the volume of LV in the RT field was the most significant predictor of perfusion defects on both univariate (p = 0.0005 to 0.0058) and multivariate analysis (p = 0.0026 to 0.0029). Body mass index (BMI) was the only significant patient-specific factor on both univariate (p = 0.0005 to 0.022) and multivariate analysis (p = 0.0091 to 0.05). In patients with very small volumes of LV in the planned RT fields, the rate of perfusion defects was significantly higher when the fields set-up "too deep" (83% vs. 30%, p = 0.059). The frequency of deep set-up errors was significantly higher among patients with BMI > or =25 kg/m2 compared with patients of normal weight (47% vs. 28%, p = 0.068).

CONCLUSIONS

BMI > or =25 kg/m2 may be a significant risk factor for cardiac toxicity after RT for left-sided breast cancer, possibly because of more frequent deep set-up errors resulting in the inclusion of additional heart in the RT fields. Further study is necessary to better understand the impact of patient-specific factors and set-up errors on the development of RT-induced perfusion defects.

Complete heart block after mediastinal irradiation in a patient with the Wolff-Parkinson-White syndrome

Radiation therapy is the current standard therapy for several malignant disorders, including Hodgkin's disease. Cardiac complications, pericardial disease in particular, may develop long after the treatment. However, conduction disorders have rarely been described. We report a patient with the Wolff-Parkinson-White syndrome who developed complete heart block 16 years after mediastinal radiation therapy.

Severe infundibular pulmonary stenosis and coronary artery stenosis with ventricular tachycardia 24 years after mediastinal irradiation

A 28-year-old man developed severe infundibular pulmonary stenosis (PS), coronary artery stenosis with sustained ventricular tachycardia (VT) 24 years after mediastinal irradiation (total amount of 40 Gray) for non-Hodgkin's lymphoma. Repair of right ventricular outflow tract and coronary artery bypass graft procedure were performed. Infundibular PS was successfully relieved after operation and VT was also controlled by medication. Mediastinal irradiation often causes various cardiac complications after a latent period. Therefore, continuous careful observation is mandatory in patients with the history of mediastinal irradiation.

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.

Pulmonary complications of radiation therapy

There have been important developments in understanding the difference in pathogenesis and clinical significance between acute or sporadic pneumonitis and late radiation fibrosis. Corticosteroid therapy and other forms of therapy are useful in the treatment of acute pneumonitis. Late radiation fibrosis is refractory to treatment; therefore, minimizing the likelihood of developing it is particularly important. Baseline lung assessments are appropriate in patients who are clinically at risk. A new development is the use of the DVH to compare radiation treatment plans to minimize the volume of normal lung irradiated in patients who are at risk. It is hoped that the study of mechanisms that lead to the development of radiation fibrosis will point the way to possible future therapies. Patients who are included in studies of novel irradiation treatments for lung cancer need, in particular, to be monitored for late radiation lung toxicity.

Diastolic heart failure in female patient 20 years after radiotherapy due to Hodgkin’s disease—a case report

We present the case of a 36-year-old female with severe heart failure which developed 20 years after irradiation due to Hodgkin's disease.

A case of refractory bilateral pleural effusion due to post-irradiation constrictive pericarditis

A 51-year-old woman suffering from dyspnoea and refractory bilateral pleural effusions is discussed. The effusion was characterized as a transudate and cardiac decompensation and renal insufficiency were initially suspected. Diuretic agents were not effective and the patient required bilateral chest water-sealed drainage tubes for 4 months, after exclusion of neoplastic infiltration, collagen disease and other cardiac disorders. On echocardiogram, cardiac function and other findings were almost normal, except for shortening of deceleration time in transmitral flow velocity. To evaluate the reduced diastolic compliance, cardiac catheterization was performed, and revealed an elevated pressure in the right ventricle with a dip-and-plateau pattern, and constrictive pericarditis was diagnosed. The hydrothorax resolved after pericardiectomy and symptoms were alleviated. Three and a half years after surgery, the patient is well and taking only oral diuretics. The underlying mechanism of cardiac disorder appears to have been mixed restriction and constriction due to irradiation of her chest for breast cancer 13 years ago. Because the echocardiogram was within normal limits, the diagnosis was delayed. Radiation-induced constrictive pericarditis should be considered if there is an unexplained transudate effusion with a normal echocardiogram.

Chemotherapy for metastatic breast cancer-report of a European expert panel

The anthracyclines doxorubicin and epirubicin, and the taxanes paclitaxel and docetaxel, are effective chemotherapeutic agents for the first-line and second-line treatment of metastatic breast cancer, and their clinical use is widespread. However, for women whose disease has progressed despite receiving these drugs, treatment options are limited. These women often have a good performance status, and may survive for many months or even years, so they should be given the opportunity to benefit from further chemotherapy. The goals of chemotherapy in these patients are to obtain maximum control of symptoms, prevent serious complications, and increase survival without diminishing quality of life. Several agents are used for this purpose, including fluorouracil, docetaxel (in patients who have already received paclitaxel), vinorelbine, and mitomycin c, but because data from controlled trials are limited, a standard regimen has not yet been established. Moreover, these agents may be inconvenient to administer and can be associated with adverse events requiring hospitalisation. Therefore, there is a clear need for additional therapeutic options for patients with metastatic breast cancer. Ideally, agents should have a convenient method of administration, eg, oral, and should be suitable for home-based rather than hospital-based therapy. Treatment should control disease in at least 20-30% of patients with an acceptable side-effect profile. Novel oral therapies have now been developed and are being used increasingly in patients whose disease has progressed following taxane therapy.

Valvular heart operation in patients with previous mediastinal radiation therapy

BACKGROUND

The outcome of valvular heart operations in patients with previous mediastinal radiation therapy was studied.

METHODS

This is a single center retrospective study of 60 patients (37 females, 23 males) with a mean age of 62 +/- 15 years (28 to 88 years old) operated on from January 1976 to December 1998. Valvular heart operations performed included aortic valve replacements (n = 26), mitral valve procedures (n = 16), tricuspid valve procedures (n = 6), and multiple valve procedures (n = 12). A total of 264 clinical, hemodynamic, electrocardiographic and echocardiographic variables were analyzed.

RESULTS

Total follow-up was 199 patient-years with a mean of 3.3 +/- 3.1 years and a range of 0 to 12.4 years old. Early mortality was 7 patients (12%). Early mortality in patients with constrictive pericarditis was 40% (4 of 10) compared with 6% (3 of 50) in patients without constrictive pericarditis. By univariate analysis, early mortality was associated with constrictive pericarditis (p = 0.011), reduced preoperative ejection fraction (p = 0.015), and longer cardiopulmonary bypass times (p = 0.037). A total of 14 patients (23%) required permanent pacemaker placement before (n = 7), during (n = 1), or early (n = 6) after valvular heart operations. There were 19 late deaths (malignancies, 7; heart failures, 5; other cardiac, 4; and other noncardiac, 3). Overall survival and freedom from late cardiac death and cardiac reoperation at 5 years for hospital survivors were 66% +/- 8%, 82% +/- 7%, and 93% +/- 4%, respectively. By univariate analysis, late cardiac death was associated with low ejection fraction (p = 0.002), New York Heart Association (NYHA) functional class IV (p = 0.004), preoperative congestive heart failure (p = 0.02), and preoperative atrial fibrillation (p = 0.038). Eighty-five percent of the discharged patients were in NYHA functional class I or II at follow-up.

CONCLUSIONS

Early results of valve replacement after mediastinal radiation therapy were good except in the presence of constrictive pericarditis. Long-term outcome was limited by malignancy and heart failure. Early surgical intervention is recommended before the development of risk factors for late death, namely, severe symptoms, left ventricular dysfunction, and atrial fibrillation.

Primary mediastinal B-cell lymphoma: a review of pathology and management

PURPOSE

Primary mediastinal B-cell lymphoma (PMBL) is recognized as a separate disease entity in the REAL classification. There is uncertainty about the relevance and especially the optimal management of this disorder. In this review, we discuss clinical presentation, pathology, pathobiology, and management of PMBL in order to provide a platform for initiation of further clinical and biologic studies.

MATERIALS AND METHODS

Studies were identified through a MEDLINE search and from the bibliographies of relevant articles.

RESULTS

PMBL is a tumor of young adults who present with a rapidly proliferating tumor. At diagnosis, the tumor is usually limited to intrathoracic organs. Spread to parenchymal organs such as liver, kidneys, and CNS is common at recurrence. Fibrosis and the presence of so-called clear cells are distinctive morphologic features of PMBL, although they are not pathognomonic or even necessary for diagnosis. On the other hand, biologic features relating to oncogene rearrangement and overexpression as well as cytogenetic features clearly differentiate PMBL from other types of diffuse large B-cell lymphoma. Phase II studies and retrospective series indicate cure rates that range from 38% to 88%. The role of chemotherapy, radiation, and high-dose chemotherapy with stem cell rescue in the management of PMBL is reviewed.

CONCLUSION

PMBL has unique clinical and biologic characteristics that are radically different from those of other types of diffuse large B-cell lymphoma. Although relatively rare, its aggressive growth and its occurrence in young patients increase the clinical relevance of this entity. The consistent recognition and study of PMBL will allow the development of new approaches to its management.

Long-term chemotherapy-related cardiovascular morbidity

As a consequence of the successful use of chemotherapy in the treatment of curable neoplasms such as germ cell tumours and malignant lymphomas, and the increasing application of primary and adjuvant chemotherapy for various tumour types, the number of patients with a prolonged life expectancy after treatment is rising. Attention to long-term side-effects, including cardiovascular toxicity, is therefore of growing importance. In this review we evaluate the literature on long-term cardiovascular toxicity related to chemotherapy in adult patients. Two categories of patient with favourable life expectancy have been reviewed, namely patients cured of metastatic disease by chemotherapy and patients treated with adjuvant chemotherapy. In the first category, the literature on long-term cardiovascular morbidity in survivors of metastatic testicular cancer and lymphomas is discussed, while in the second category this is done for patients treated with adjuvant chemotherapy for breast and colon cancer. As well as the direct toxic effects of chemotherapy on the cardiovascular system, the indirect toxic effects such as chemotherapy-related metabolic changes that may cause cardiovascular morbidity are also discussed.

Transesophageal echocardiography assessment of severe ostial left main coronary stenosis

Doppler echocardiography is commonly used in the assessment of stenotic valvular orifices. We describe the application of transesophageal echocardiography for the detection of a critical ostial left main coronary stenosis. Because preoperative coronary angiography often is not routinely performed in young patients undergoing valve surgery, application of Doppler echocardiography can potentially prevent catastrophic complications, particularly in atypical cases.

Long-term cardiac mortality following radiation therapy for Hodgkin's disease: analysis with the relative seriality model

PURPOSE

(a) To assess the increased risk of death due to ischemic heart disease (IHD) in a group of patients treated for Hodgkin's disease (HD) with radiation therapy (RT) as the primary treatment. (b) To quantify the dose response of IHD using a biophysical model.

MATERIALS AND METHODS

Patient material consisted of 157 patients diagnosed for HD between 1972 and 1985 who received RT as the primary treatment at Radiumhemmet, Karolinska Hospital. The general population formed the control group. The RT treatments were reconstructed based on the individual treatment data and simulator films. Individual clinical and dosimetrical data were analyzed with the relative seriality model. The material was also analyzed grouping the material according to dose-volume constraints.

RESULTS

Of the 157 patients, 13 (8.3%) died due to IHD. The standardized mortality ratio (SMR) was 5.0 (95% CI, 2.7-8.6). Analysis of dose-volume histograms (DVH) showed an increasing risk with increasing dose to a larger volume fraction. The observed individual clinical complication data could not be modeled unambiguously. The group analysis resulted in the dose-response parameters: D(50)=71 Gy, gamma=0.96 and s=1.0.

CONCLUSIONS

A significantly increased risk of death due to IHD following RT for HD was found. The risk was found to increase with higher dose and larger volume fraction irradiated.

Cardiac and pulmonary toxicity in patients undergoing high-dose chemotherapy for lymphoma and breast cancer: prognostic factors

We sought to define risk factors predisposing breast cancer and lymphoma patients to cardiac and pulmonary toxicity when undergoing high-dose chemotherapy (HDC) and autologous stem cell rescue (ASCR). Additionally, we evaluated in depth the predictive value of the ejection fraction measured prior to HDC in determining cardiac toxicity. In this retrospective analysis, 24 variables were examined in 138 patients undergoing HDC and ASCR from 1990 until 1995. Logistic regression models were used to model the probability of experiencing cardiac and pulmonary toxicity as a function of the 24 prognostic covariates. Cardiac toxicity occurred in 12% of patients and pulmonary toxicity in 24% of patients. Bivariate analyses showed that patients with lymphoma (as opposed to breast cancer) and those with a higher cardiac risk factor score were more likely to experience cardiac toxicity. Multivariate logistic regression models predicted lymphoma and older age to be risk factors for cardiac toxicity. History of an abnormal ejection fraction and higher doses of anthracyclines prior to HDC may also contribute to cardiac toxicity. Pulmonary toxicity occurred more commonly in lymphoma than breast cancer patients, likely due to the busulfan used in the HDC regimen. No other risk factors for pulmonary toxicity were identified. We conclude that older patients with lymphoma should be carefully evaluated prior to being accepted for HDC programs. Older patients with breast cancer may tolerate this procedure well. There is a trend towards cardiac toxicity in patients with a past history of low ejection fraction, although seemingly poor cardiac risk patients may fare well with HDC if carefully selected with the aid of a thorough cardiac evaluation.

Fatal cardiovascular complication 19 years after treatment for fibrosarcoma

Fibrosarcoma accounts for 3% of all primary bone tumours. It most commonly occurs in the metaphyseal areas of long bones around the knee, and may metastasize to the lungs (Neff, 1991). Here we report a case of a fatal cardiovascular complication 19 years after successful treatment of fibrosarcoma with chemotherapy and radiotherapy.

Coronary artery bypass grafting in patients with previous mediastinal radiation therapy

OBJECTIVES

Our objectives were to characterize the outcome of coronary artery bypass grafting in patients with previous mediastinal radiation therapy and to identify special features of this condition that relate to surgical management.

PATIENTS AND METHODS

We conducted a retrospective review of 47 patients (28 women, 19 men) with a mean age of 63.5 +/- 12.8 years (range 31.0-82. 9 years) from 1976 through December 1996 undergoing coronary artery bypass graft after mediastinal radiation therapy.

RESULTS

The mean interval between mediastinal radiation therapy and coronary artery bypass grafting was 15.1 +/- 9.8 years (range 1.1-37.8 years). In the 44 patients with isolated coronary surgery, operative mortality was 3 patients (6.8%). Sternal wound infection occurred in 3 patients (6.8%). Actuarial survival at 1 and 5 years was 87.2% +/- 4. 9% and 71.6% +/- 7.1%, respectively. Total follow-up was 293.7 patient-years (mean 6.2 +/- 5.1 years). There were 17 late deaths (malignancy, n = 7; heart failure, n = 6; stroke, n = 1; other noncardiac causes, n = 2; and sudden death, n = 1). Twelve of 43 discharged patients had the development of valvular disease demonstrated by follow-up echocardiography.

CONCLUSIONS

The early results of coronary artery bypass grafting for the treatment of ischemic heart disease after mediastinal radiation therapy are good. Late survival, however, is limited by malignancy, either recurrent or new, and the development of heart failure. Inasmuch as 25 other patients after radiation therapy required concomitant valve surgery and 12 of 43 (28%) discharged patients had later development of valvular disease, with 2 requiring reoperation, careful assessment of any valvular lesion is important during the initial coronary artery bypass grafting. Careful follow-up, including regular echocardiographic screening, is recommended in this patient population.

[Acute cardiogenic postoperative edema after doxorubicin (adriamycin) chemotherapy]

We describe a case of postoperative congestive heart failure in a young woman of physical class ASA 1, following breast cancer surgery. Preoperatively she had been treated with doxorubicin (Adriamycin) 450 mg.m-2, total dose, associated with breast and ovarian radiotherapy. This association was probably the cause of postoperative heart failure. Twenty-four hours after surgery, a two-dimensional echocardiography showed a severe left ventricular dysfunction, whereas preoperative clinical assessment was unremarkable. Doxorubicin cardiotoxicity can be acute, subacute and delayed as in our case. Clinical assessment and ECG are not sensitive indicators of such cardiac damage. Preoperative echography is the technique of choice for the evaluation of the cardiac status of a patient treated with a high cumulative dose of doxorubicin and mediastinal irradiation.

Intraarterial beta irradiation to reduce restenosis after PTCA. Experimental and clinical experience

The present data demonstrate clinical feasibility of intracoronary beta brachytherapy and fail to reveal any complications that could be attributed to it. Definitive conclusions regarding safety will have to await longer term evaluation. Proof of efficacy will require strict dose finding evaluation of higher doses than those used in the present pilot study followed by a controlled, randomized trial using both clinical and angiographic end-points.

[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.

Early effects of acute gamma-radiation on vascular arterial tone

1. To determine the acute effects of irradiation on the functionality of vessel, rat aortic rings were mounted in an organ bath for isometric tension measurements and irradiated (60Co, 1 Gy min(-1), 15 min). 2. Irradiation, which is without effect on non-contracted or endothelium-denuded vessels, led to an immediate and reversible increase in vascular tone on (-)-phenylephrine (1 microM)-precontracted aortic rings. The tension reached a plateau about 5 min after the beginning of irradiation. 3. The maximal radiation-induced contraction occurred on aortic rings relaxed by acetylcholine (ACh) (1 microM). In this condition, the addition of catalase (1000 u ml(-1)), which reduces hydrogen peroxide, and DMSO (0.1% v/v), which scavenges hydroxyl radical, had no influence on tension level while superoxide dismutase (SOD) (100 u ml(-1)), a superoxide anion scavenger, reduced the observed contraction. A similar result was obtained in the presence of indomethacin (10 microM), a cyclo-oxygenase blocker. 4. Pretreatment of rings with the nitric oxide synthase inhibitor, N(omega)-nitro-L-arginine methyl ester (L-NAME) (10-100 microM) inhibited the radiation-induced contraction. 5. This effect was dose rate-dependent and even occurred for a very low dose rate (0.06 Gy min(-1)). 6. The present results indicate that gamma-radiation induces an instantaneous vascular tone increase that is endothelium and dose rate-dependent. This effect is (i) maximal when nitric oxide (NO) is produced, (ii) greatly reduced by SOD and (iii) inhibited by L-NAME, suggesting a major involvement of complexes between NO and superoxide anion.

Feasibility of intracoronary beta-irradiation to reduce restenosis after balloon angioplasty. A clinical pilot study

BACKGROUND

With the aim of decreasing the incidence of restenosis after coronary balloon angioplasty, we developed a technique of intracoronary beta-irradiation using an endoluminally centered pure metallic 90Y source. The purpose of the present study was to evaluate the clinical feasibility and safety profile of this approach with a dose of 18 Gy delivered to the inner arterial surface.

METHODS AND RESULTS

Between June 21 and November 15, 1995, fifteen patients (6 women and 9 men; mean age, 71 +/- 5 years) underwent intracoronary beta-irradiation immediately after a conventional percutaneous transluminal coronary angioplasty (PTCA) procedure. The PTCA/irradiation procedure was technically feasible in all attempted cases, and the delivery of the 18 Gy dose was accomplished without complications. In 4 patients, the intervention was completed through intra-arterial stent implantation because of dissection induced by the initial PTCA. During the follow-up period of 178 +/- 17 days (range, 150 to 225 days), no complication occurred that could be attributed to radiation therapy. No aneurysm or angiographically detectable thrombus was observed in any of the irradiated arterial segments. The clinical event rate (4 of 15 patients underwent further target lesion revascularization) and the angiographic follow-up (6 of 15 patients had a > 50%-diameter stenosis at the previously treated site) did not suggest a marked impact on the expected restenosis rate.

CONCLUSIONS

This early experience demonstrates that our approach is feasible, and no side effects attributable to radiation were noted during a 6-month period of follow-up. Whether higher doses of beta-irradiation will favorably affect post-PTCA restenosis in patients must await further evaluation.

The radiobiology of intravascular irradiation

PURPOSE

There is increasing interest in the use of vascular irradiation, from an internally introduced radioactive source to control restenosis after balloon angioplasty. Both animal experiments and early clinical studies appear to show promising results in this regard. We consider various mechanistic interpretations of the experimental and clinical observations that doses of 12-20 Gy appear to be efficacious in preventing restenosis. We develop and investigate simple models, both experimental and theoretical, of the kinetics of radiation-induced smooth muscle cell (SMC) inactivation and regrowth, as a first step toward optimizing the design of clinical vascular irradiation.

METHODS AND MATERIALS

Using in vitro models of human SMCs, we investigate the relative radiosensitivity of SMCs compared with endothelial cells and measure the dose-dependent ability of SMCs to repopulate a denuded region in a confluent layer of cells. We then use quantitative information on the number, radiation sensitivity, and growth rate of the potential arterial target cells to model the time course of the SMC population after irradiation.

RESULTS AND CONCLUSION

Doses >20 Gy, which would be required to completely eliminate the SMC population which has the potential to cause restenosis, are too large to be practical because of the unacceptable risk of late complications. However, doses that can be practically given in vascular irradiation (<20 Gy) will certainly delay restenosis by 1-3 years, with larger doses producing longer delays. Whether such doses can avert restenosis permanently is unclear, as permanent prevention at realistic doses depends critically on the assumption that those SMCs which survive irradiation have a significantly limited capacity for proliferation. With regard to current animal model experiments, routine follow-up of <1 year, which is standard practice, is probably too short to address some of the key mechanistic question in intravascular radiation therapy.