Coronary artery operation in radiation-associated atherosclerosis: long-term follow-up

Duplex Imaging Assessment of the Internal Mammary Arteries in Women after Unilateral Mastectomy and Radiotherapy for Breast Cancer

BACKGROUND

The effects of incidental radiation exposure on internal mammary arteries remain unclear. The present study was designed to test the hypothesis by comparing diameter and blood flow of the irradiated and nonirradiated internal mammary arteries, using Duplex ultrasound imaging.

METHODS

The study was designed as a single-center, transversal, comparative study. The main outcomes were diameter and volumetric blood flow of the internal mammary arteries. The Wilcoxon rank-sum test was used to assess the differences between the irradiated and nonirradiated internal mammary arteries with regard to the diameter and volumetric blood flow.

RESULTS

The diameter (median [interquartile range]) of the irradiated internal mammary arteries (0.170 mm [0.160, 0.180]) was smaller than that of the contralateral nonirradiated ones (0.180 mm [0.170, 0.200], P < 0.0001) and that of the internal mammary arteries in the control group (0.180 mm [0.170, 0.190], P < 0.0001). Similarly, blood flow (median [interquartile range]) of the irradiated internal mammary arteries (52.4 ml/min [37.78, 65.57]) was smaller than that of the contralateral nonirradiated ones (62.7 ml/min [46.87, 84.17], P < 0.0001), as well as of the left (56.7 ml/min [46.88, 72.58], P = 0.02) and the right internal mammary arteries in the control group (61.0 ml/min [47.47, 74.52], P = 0 0.0009).

CONCLUSIONS

The data indicate that the irradiated internal mammary arteries in patients with a history of total mastectomy followed by radiotherapy for breast cancer had significantly smaller diameter and blood flow compared to the nonirradiated internal mammary arteries.

Preclinical models of radiation-induced cardiac toxicity: Potential mechanisms and biomarkers

Radiation therapy (RT) is an important modality in cancer treatment with >50% of cancer patients undergoing RT for curative or palliative intent. In patients with breast, lung, and esophageal cancer, as well as mediastinal malignancies, incidental RT dose to heart or vascular structures has been linked to the development of Radiation-Induced Heart Disease (RIHD) which manifests as ischemic heart disease, cardiomyopathy, cardiac dysfunction, and heart failure. Despite the remarkable progress in the delivery of radiotherapy treatment, off-target cardiac toxicities are unavoidable. One of the best-studied pathological consequences of incidental exposure of the heart to RT is collagen deposition and fibrosis, leading to the development of radiation-induced myocardial fibrosis (RIMF). However, the pathogenesis of RIMF is still largely unknown. Moreover, there are no available clinical approaches to reverse RIMF once it occurs and it continues to impair the quality of life of long-term cancer survivors. Hence, there is an increasing need for more clinically relevant preclinical models to elucidate the molecular and cellular mechanisms involved in the development of RIMF. This review offers an insight into the existing preclinical models to study RIHD and the suggested mechanisms of RIMF, as well as available multi-modality treatments and outcomes. Moreover, we summarize the valuable detection methods of RIHD/RIMF, and the clinical use of sensitive radiographic and circulating biomarkers.

Radiation-Induced Vascular Disease-A State-of-the-Art Review

Since the 1990s, there has been a steady increase in the number of cancer survivors to an estimated 17 million in 2019 in the US alone. Radiation therapy today is applied to a variety of malignancies and over 50% of cancer patients. The effects of ionizing radiation on cardiac structure and function, so-called radiation-induced heart disease (RIHD), have been extensively studied. We review the available published data on the mechanisms and manifestations of RIHD, with a focus on vascular disease, as well as proposed strategies for its prevention, screening, diagnosis, and management.

Vascular toxic effects of cancer therapies

Cancer therapies can lead to a broad spectrum of cardiovascular complications. Among these, cardiotoxicities remain of prime concern, but vascular toxicities have emerged as the second most common group. The range of cancer therapies with a vascular toxicity profile and the clinical spectrum of vascular toxic effects are quite broad. Historically, venous thromboembolism has received the greatest attention but, over the past decade, the arterial toxic effects, which can present as acute vasospasm, acute thrombosis and accelerated atherosclerosis, of cancer therapies have gained greater recognition. This Review focuses on these types of cancer therapy-related arterial toxicity, including their mechanisms, and provides an update on venous thromboembolism and pulmonary hypertension associated with cancer therapies. Recommendations for the screening, treatment and prevention of vascular toxic effects of cancer therapies are outlined in the context of available evidence and society guidelines and consensus statements. The shift towards greater awareness of the vascular toxic effects of cancer therapies has further unveiled the urgent needs in this area in terms of defining best clinical practices. Well-designed and well-conducted clinical studies and registries are needed to more precisely define the incidence rates, risk factors, primary and secondary modes of prevention, and best treatment modalities for vascular toxicities related to cancer therapies. These efforts should be complemented by preclinical studies to outline the pathophysiological concepts that can be translated into the clinic and to identify drugs with vascular toxicity potential even before their widespread clinical use.

[Post Radiotherapy Lesions of the Heart Valves. Principles of Diagnosis and Results of Treatment]

BACKGROUND

The use of radiation therapy for the treatment of tumors of the chest сan lead to the development of cardiac pathology, including that of the valves and coronary arteries.

STUDY AIM

to analyze the specifics of post-radiation lesions of the valvular apparatus and coronary arteries, and to assess the immediate results and risks of surgical correction of detected defects. Materials and  methods. In the Emergency department of surgery of acquired heart disease of A. N. Bakulev National Medical Research Center of Cardiovascular Surgery in the period from 2004 to 2017 were examined and operated 46 patients aged 35-81 years (mean age 56±12.4 years, 80 % women). The period from primary irradiation of the chest to surgical treatment of valvular pathology ranged from 4 to 40 years. Indications for thoracic radiotherapy were Hodgkin's lymphoma in 23 patients (50 %), breast cancer - in 20 (43 %).

RESULTS

Stenosis of the aortic valve was the leading defect in 42 patients (91 %). According to coronary angiography, coronary artery disease was diagnosed in 31 patients (67 %). Isolated aortic valve prosthesis was performed in 14 (30 %) patients, other operations were combined. Hospital mortality was 11 % (5 patients). There were no deaths among patients who underwent radiation therapy after mastectomy. Main nonlethal complications were: pericardial effusion in 6 patients (13 %), hydrothorax requiring repeated pleural punctures in 5 patients (11 %).

CONCLUSION

The variety of clinical manifestations of radiation heart disease and its progressive nature emphasize the need for long-term dynamic observation of patients after thoracic irradiation in order to timely identify the pathology and eliminate the risk of sudden cardiac complications and the development of severe heart failure decompensation.

Is Radiation a Risk Factor for Atherosclerosis? An Echo-Color Doppler Study on Hodgkin and Non-Hodgkin Patients

Aims and background

The aim of the present paper was to study the role of irradiation in the atherosclerotic process in patients affected by Hodgkin and non-Hodgkin lymphoma.

Methods

We studied 84 subjects, 42 with Hodgkin or non-Hodgkin disease and 42 controls. All 42 cases had been irradiated and were comparable in terms of risk factors for atherosclerosis. All 84 subjects underwent echo-color Doppler of the arterial axis (carotids, abdominal aorta, and femoral arteries), and the intima-media thickness was measured.

Results

The irradiated cases had a greater intima-media thickness in the carotid district, even after dividing them according to age and sex; males were affected more than females. The irradiated patients were at greater risk of developing cardiovascular events than the controls.

Conclusions

An echo-color Doppler of the carotid district is advisable in all patients who have been submitted to radiotherapy, and the patients with a significantly greater than normal intima-media thickness need a strict follow-up, and antioxidant or antiaggregant therapy should be considered.

Coronary artery bypass grafting in patients treated with thoracic radiation: a case-control study

Background and aim

Thoracic radiation therapy (XRT) for cancer is associated with the development of significant coronary artery disease that may require coronary artery bypass grafting surgery (CABG). Contemporary acute surgical outcomes and long-term postoperative survival of patients with prior XRT have not been well characterised.

Methods

This was a retrospective, single-centre study of patients with a history of thoracic XRT who required CABG and who were propensity matched against 141 controls who underwent CABG over the same time period. The objectives were to assess early CABG outcomes and long-term survival in patients with prior XRT.

Results

Thirty-eight patients with a history of previous thoracic XRT underwent CABG from 1994 to 2013. The median time from XRT exposure to surgery was 7.9 years (IQR: 2.5–18.4 years). Perioperative adverse events were similar in the XRT group and controls; however, there was a trends lower utilisation of internal mammary artery (IMA) grafts in the XRT group (89%vs98%, P=0.13). After a median postoperative follow-up of 5.4 years (IQR 0.9–9.4 years), no difference in long-term all-cause mortality was observed.

Conclusion

Patients with prior thoracic XRT who undergo CABG have similar long-term all-cause mortality compared with controls. Isolated CABG after thoracic XRT is not associated with higher perioperative complications, but IMA graft use may be limited by prior XRT.

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.

Isolated left main coronary artery stenosis after thoracic radiation therapy: to operate or not to operate

Radiation therapy of neoplasms involving the chest or mediastinum results in a wide spectrum of cardiac complications including coronary artery disease, which can present in patients with few or no traditional cardiac risk factors. We report a case of radiation induced coronary artery disease in a 60-year-old female with a history of stage IIIA nonsmall cell lung carcinoma which was diagnosed eight years earlier and treated with chemotherapy and radiotherapy. She presented to the hospital with atypical chest pain that had occurred intermittently over the preceding week. Her initial electrocardiogram and cardiac enzymes were within normal limits. However, following an indeterminate exercise nuclear stress test, she developed chest pain and elevated cardiac enzymes. Coronary angiography demonstrated 90% stenosis of the left main coronary artery ostium, without any evidence of atherosclerotic disease or stenosis in other coronary arteries. She underwent surgical revascularization, which revealed dense adhesions surrounding the heart. During surgery, she developed severe bleeding and died. Coronary artery disease can present within years of radiation exposure, and ostial lesions are typical. Treatment is often challenging because of the effects of radiation on other tissues and the risks of revascularization procedures. Therefore, a multidisciplinary team approach should be considered.

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.

Cardiovascular complications of radiation therapy for thoracic malignancies: the role for non-invasive imaging for detection of cardiovascular disease

Radiation exposure to the thorax is associated with substantial risk for the subsequent development of cardiovascular disease. Thus, the increasing role of radiation therapy in the contemporary treatment of cancer, combined with improving survival rates of patients undergoing this therapy, contributes to a growing population at risk of cardiovascular morbidity and mortality. Associated cardiovascular injuries include pericardial disease, coronary artery disease, valvular disease, conduction disease, cardiomyopathy, and medium and large vessel vasculopathy-any of which can occur at varying intervals following irradiation. Higher radiation doses, younger age at the time of irradiation, longer intervals from the time of radiation, and coexisting cardiovascular risk factors all predispose to these injuries. The true incidence of radiation-related cardiovascular disease remains uncertain due to lack of large multicentre studies with a sufficient duration of cardiovascular follow-up. There are currently no consensus guidelines available to inform the optimal approach to cardiovascular surveillance of recipients of thoracic radiation. Therefore, we review the cardiovascular consequences of radiation therapy and focus on the potential role of non-invasive cardiovascular imaging in the assessment and management of radiation-related cardiovascular disease. In doing so, we highlight characteristics that can be used to identify individuals at risk for developing post-radiation cardiovascular disease and propose an imaging-based algorithm for their clinical surveillance.

Surgical management of coronary artery disease associated with malignancy

Surgical management of patients with combined coronary artery disease and malignancy remains a challenge. In this review the time of surgical intervention, whether to treat the malignancy or the coronary artery disease first, and which bypass technique should be used during myocardial revascularization are reviewed to determine the most optimal strategy to manage patients who require coronary surgical revascularization and present with an underlying malignancy.

Cardiac toxicity in association with chemotherapy and radiation therapy in a large cohort of older patients with non-small-cell lung cancer

BACKGROUND

The study's objective was to investigate the risks of developing cardiac disorders following the administration of chemotherapy and radiation therapy in patients with non-small-cell lung cancer (NSCLC).

METHODS

The study consisted of 34 209 patients aged > or =65 years with American Joint Committee on Cancer stages I-IV NSCLC identified from the Surveillance, Epidemiology, and End Result-Medicare linked database (1991-2002) who were free of cardiac disorders at NSCLC diagnosis.

RESULTS

There were significant associations between the use of chemotherapy/radiation and the risks of developing ischemic heart disease, conduction disorders, cardiac dysfunction, and heart failure. The absolute risks for cardiac dysfunction increased with the administration of chemotherapy-only and radiation-only, and incrementally with chemoradiation. Men, blacks, older patients, those with higher comorbidity scores, and advanced disease were at higher risk. The risk for ischemic heart disease increased when radiation/chemoradiation were rendered to the left lung and both lungs and for cardiac dysfunction, radiation administered to the left lung.

CONCLUSIONS

There were significant associations especially for cardiac dysfunction with use of chemotherapy/radiation therapy and risks of developing cardiac toxicity in NSCLC patients. The risks of treatment-associated cardiac toxicity, specifically ischemic heart disease and cardiac dysfunction, were greatest among those with left-sided lung tumors.

Cardiac surgery in patients irradiated for Hodgkin's lymphoma

Background/Objectives. Therapy for Hodgkin's lymphoma is disease specific and cannot be compared with treatment for other diseases. It often includes more extensive radiotherapy on the mediastinum than for other malignancies. Cardiac morbidity is known to occur in patients previously irradiated. This study describes the postoperative course after cardiac surgery of patients previously irradiated for Hodgkin's lymphoma.Methods. From January 1990 until June 2008, 12 patients underwent cardiac surgery in the University Medical Center Utrecht after previous irradiation for Hodgkin's lymphoma. Data on radiotherapy, surgery and follow-up were collected retrospectively. The postoperative functional status was assessed by a telephone questionnaire.Results. Atrial fibrillation (33%) and pleural effusion (25%) were the most common postoperative complications. After a mean followup of 2.6+/-2.9 years four patients had died. The remaining patients were all in a favourable New York Heart Association and Canadian Cardiothoracic Society class. The estimated one-, two- and four-year survival rates were 83, 69 and 46% respectively.Conclusion. The early postoperative outcome of cardiac surgery in this population is reasonably good. The long-term results may prove to be disappointing, but the cohort is small. (Neth Heart J 2010;18:61-5.).

Conduit choice for coronary artery bypass grafting after mediastinal radiation

OBJECTIVE

Patients who have undergone prior mediastinal radiation might require coronary artery bypass grafting. However, there is some concern regarding potential radiation damage to the internal thoracic artery. Our objective was to assess the late patency of the internal thoracic artery and venous grafts in patients with prior mediastinal radiation.

METHODS

Patients undergoing coronary artery bypass grafting at our clinic after prior mediastinal radiation were identified, and medical records, including operative reports, clinical notes, and coronary angiography, were reviewed.

RESULTS

Between 1985 and 2005, 138 patients had coronary artery bypass grafting after mediastinal radiation. Of these, 25 underwent clinically indicated postoperative angiography. The mean patient age was 56.1 +/- 13.8 years, and 24% were female. All patients received between 3000 and 6000 rads in fractionated doses. Seventy-two percent of patients had 3-vessel coronary artery disease. At late angiography (mean, 2.2 years), 6 (32%) of 19 internal thoracic arteries and 13 (27%) of 48 venous or radial arterial conduits showed stenosis of 70% or greater (P = .72). Assessing only grafts that were anastomosed to the left anterior descending coronary artery, 35% (6 of 17) of internal thoracic artery grafts and 60% (3 of 5) of non-internal thoracic artery grafts showed narrowing of 70% or greater (P = .61). Among patients who received a graft to the left anterior descending coronary artery (n = 113), however, age-adjusted survival at 5 years was superior among those receiving an internal thoracic artery graft to the left anterior descending coronary artery.

CONCLUSIONS

Internal thoracic artery graft patency among patients with prior radiation was less than expected and similar to that for venous grafts, although the effect of conduit disease versus distal target vessel runoff is unknown. Despite this, late survival was superior among those receiving an internal thoracic artery graft to the left anterior descending coronary artery. These data support use of an internal thoracic artery graft to the left anterior descending coronary artery when it appears grossly to be an acceptable conduit.

Coronary artery disease after radiation therapy for Hodgkin's lymphoma: coronary CT angiography findings and calcium scores in nine asymptomatic patients

OBJECTIVE

Long-term survivors of Hodgkin's lymphoma treated with radiation therapy have an increased incidence of coronary artery disease. The purpose of this study is to describe the coronary CT angiography findings and calcium scores of asymptomatic patients who had mediastinal irradiation for Hodgkin's lymphoma and to evaluate the impact of coronary CT angiography on patient management.

MATERIALS AND METHODS

We evaluated nine consecutive patients, age range 35-60 years, who had been treated for Hodgkin's lymphoma by radiation therapy between the ages of 11 and 27 years. The total mediastinal dose ranged from 34 to 45 Gy. All patients were evaluated with 64-MDCT with calcium scoring followed by CT angiography of the coronary arteries. Imaging findings and clinical follow-up were analyzed.

RESULTS

Eight of nine patients had coronary artery disease. CT showed long segments of diffuse disease; areas of stenosis from soft plaque; and calcification in the proximal right coronary, left anterior descending, and left circumflex arteries. Calcium scores were significantly higher than in other patients of this age group. Additional tests, including selective coronary angiography, were necessary in patients with diffuse disease with calcifications. CT evaluation led to bypass surgery and angioplasty in two patients.

CONCLUSION

Coronary CT angiography and calcium scores are useful tools for evaluation of irradiation-related coronary artery disease. Complementary tests might be necessary in selected patients. Prospective larger studies are needed to better define the role of coronary CT angiography and calcium scores and to establish an algorithm for evaluation and treatment of these patients.

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.

Left Breast Necrosis Following Cardiac Bypass Surgery

The following is a case report of left breast necrosis following coronary artery bypass grafting (CABG) in a woman previously treated for a stage I breast carcinoma. To our knowledge this is the first such report of its kind in the literature. We believe that breast tumor extirpation and internal mammary artery utilization in combination are not sufficient insults on the vascularity of the breast to account for necrosis, but rather we feel that a variety of conditions are necessary for vascular compromise to occur.

Coronary Artery Revascularization After Chest Wall Reconstruction With Rectus Abdominis Myocutaneous Flap

The standard incision for a cardiac operation is a median sternotomy. In special situations, alternative approaches are needed. We report a 53-year-old woman who required coronary artery bypass grafting 10 days after chest wall reconstruction with a transverse rectus abdominis myocutaneous flap. We describe our technique, which allowed us to preserve the flap and resulted in good functional and aesthetic outcome.

Concomitant coronary and multiple arch vessel stenoses in patients treated with external beam radiation: pathophysiological basis and endovascular treatment

External beam radiation-induced stenoses isolated to the coronary arteries or peripheral vessels have been previously described. We report for the first time the clinical presentation of two patients with concomitant coronary artery and multiple arch vessel disease following external beam radiation of the chest. We review the pathophysiology, discuss the treatment options and describe the percutaneous treatment of coronary, carotid, subclavian, and axillary stenoses related to this rare but likely underdiagnosed disorder.

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.

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.

Coronary artery operation in patients after breast cancer therapy

OBJECTIVE

The purpose of this investigation was to retrospectively study the outcome of patients undergoing coronary artery operation who were previously treated for breast cancer.

METHODS

Between July 1992 and December 1996, 28 patients with a history of breast cancer underwent coronary artery bypass graft operation and were randomly matched against a noncancer group of similar size (n = 36) to allow for comparison of their preoperative characteristics, operative course, and postoperative outcome.

RESULTS

The incidence of sternal wound infection was significantly higher in the cancer group than in the control group (25% versus 6%; p = 0.027). Postoperative noncardiac chest pain occurred more frequently in the cancer group than in the control group (52% versus 31%; not significant). In the study group, radiotherapy and recent myocardial infarction were the only two independent factors associated with sternal wound complications. Patients with a less than 17-year interval between the breast cancer therapy and the coronary artery operation had a higher incidence of sternal wound infection (46%) as opposed to patients with a longer time interval (7%; p = 0.028; odds ratio = 12). Sternal wound complications were more frequent in patients with a history of right-sided breast cancer (50%) compared with left-sided lesions (12.5%; p = 0.068; odds ratio = 7).

CONCLUSIONS

Coronary artery operation in patients after breast cancer therapy may be associated with an increased sternal wound infection rate. To decrease this risk of infection, an approach through a right thoracotomy, minimally invasive techniques, the use of skeletonized internal mammary artery, and broad spectrum antibiotic therapy may be considered.

Surgical management of radiation-induced heart disease

BACKGROUND

With the increasing population of patients with prior mediastinal irradiation, cardiac surgeons will encounter patients with radiation-induced damage to the heart and the great vessels. Awareness of the pathology and the surgical management is essential to provide optimal care for these patients.

METHODS

Eight patients with radiation-induced heart disease were encountered in the last 10 years. After a brief clinical presentation, the surgical management of radiation-induced heart disease is reviewed.

RESULTS

Radiation can affect all the structures in the heart, including the coronary arteries, the valves, and the conduction system. The pericardium is the most commonly involved, and the conduction system is the least involved. Pericardiectomy is quite effective in patients with symptomatic pericardial effusion or constriction. The coronary lesions are located predominantly in the ostial or proximal regions of the epicardial vessels. Percutaneous transluminal coronary angioplasty alone appears to have a high rate of restenosis. Surgical revascularization has good long-term results, and the internal mammary artery should be used if it is satisfactory. The aortic and mitral valves are more commonly involved than the tricuspid and pulmonary valves. Myocardial dysfunction predominantly affects the right ventricle and requires particular attention during cardiopulmonary bypass and in the postoperative period. Restoration of sinus rhythm is essential in view of stiffness of the ventricles. Flexibility in the surgical approach with selective use of thoracotomy will facilitate the surgical procedure in certain patients.

CONCLUSIONS

Surgeons should be well versed in all the manifestations and the management of radiation-induced heart disease.

Long-term follow-up after methyl chloride intoxication

In this study, the authors investigated mortality and cancer patterns among a group of individuals accidentally exposed to methyl chloride 32 y earlier. This group of 24 persons had survived the immediate intoxication, which had occurred on a trawler during a fishing trip. The authors selected a reference group, which contained five times as many individuals as the study group, from registers of crews, and they controlled for age, occupation, social class, and lifestyle factors. The authors established a record linkage through personal identification numbers with the national death register and cancer register, thus securing 100% follow-up. The Mantel-Haenszel point estimate (M-H) was 2.2, and the 95% confidence interval (CI) was 1.3-3.1 for all causes of death. There was an excess of deaths from cardiovascular diseases (M-H = 2.1, 95% CI = 1.2-3.8). This excess mortality was more prominent among deckhands who had been subject to higher exposure; risk ratios (RRs) were elevated for all causes of death (RR = 2.5, 95% CI = 1.0-5.7), as well as for cardiovascular diseases (RR = 3.9, 95% CI = 1.0-14.4). In addition, the authors noted elevated risks for all cancers (M-H = 1.5, 95% CI = 0.3-5.6) and for lung cancer (M-H = 2.7, 95% CI = 0.1-52.6). The authors concluded that exposure to methyl chloride may have contributed to the risk of cardiovascular disease. Investigators need to conduct further studies on groups exposed to methyl chloride to refute or confirm this result.

Radiation therapy-induced cardiac injury

Radiation therapy is currently standard treatment for a number of malignancies, including Hodgkin's disease. With the advent of techniques (e.g., subcarnial blocks) that limit the dose of radiation to which the heart is exposed, the incidence of radiation-induced heart disease can be minimized. However, a small percentage of patients will eventually suffer iatrogenic effects. Most commonly seen is pericardial disease, but valvular, conduction system, and coronary artery disease are also seen. Further, because these patients are now surviving longer after therapy, those effects with a longer latent period may be seen with increasing frequency.