Fluoropyrimidines-5-fluorouracil (5-FU) and capecitabine-have been implicated as cardiotoxic chemotherapy agents. This rare, albeit potentially serious toxicity has been described in nearly four decades of case reports, case series, and in vitro modeling; however, there is a paucity in clinical trials and prospective analyses focused on cardioprotective strategies and cardiotoxic surveillance of these agents. While much attention has focused on the well-known cardiac toxicity of anthracyclines and monoclonal antibody agents such as trastuzumab, fluoropyrimidines remain one of the most common causes of chemotherapy-associated cardiotoxicity. The introduction of capecitabine, an oral prodrug of 5-FU, has made the treatment of solid tumors more convenient along with a subsequent rise in documented cardiotoxic cases. This review discusses the symptomatology, clinical manifestations, and proposed molecular mechanisms that attempt to describe the heterogeneous spectrum of fluoropyrimidine-induced cardiotoxicity. Four case examples showcasing the varied manifestations of cardiotoxicity are presented. Finally, several proposed management strategies for cardiotoxicity and post-hospital course precautions are discussed.

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Fluoropyrimidine-Induced Cardiotoxicity: Manifestations, Mechanisms, and Management.

Background:The most plausible hypothesis for takotsubo cardiomyopathy (TCM) is a catecholamine surge. Direct administration of catecholamines or medications causing catecholamine surge is frequentl...

Drug-Induced Takotsubo Cardiomyopathy.

Improvements in early diagnosis and cancer treatments have contributed to high survival rates for many cancer patients. However, these patients often die of cardiovascular disease rather than recurrence of their cancer. Heart disease manifesting after cancer may be due to several mechanisms: shared cardiovascular risks between cancer and cardiovascular disease, inflammatory states associated with malignancies, and/or cardiotoxic effects of cancer therapy. Cancer treatment increases the risk of cardiovascular diseases directly by damaging critical structures of the heart or indirectly by promoting accelerated atherosclerosis. Estimating cardiovascular risk by using advanced imaging and monitoring of the cardiac biomarkers can be used for early detection and treatment of subclinical cardiac injury. Better knowledge of these early and late cardiac effects in cancer patients will enable adoption of both primary and secondary prevention measures of long-term treatment complications in cancer survivors.

Cancer as a Risk Factor for Cardiovascular Disease

Fluoropyrimidine (FP) is used to treat a wide range of cancers; however, it is associated with drug-induced vascular toxicity, as well as angina pectoris and coronary spasm. FP has been administered for many years, although the incidence, mechanisms, and appropriate methods for managing its associated cardiovascular toxicities have not been clarified, and the management of these complications has not been standardized. This lack of evidence is not limited to FP. Many trials of anticancer agents have been conducted, excluding patients with heart diseases. Hence, there is a paucity of epidemiological data on cardiovascular adverse events caused by anticancer agents. There have been remarkable improvements in cancer treatment in recent years, with consequent improvements in prognosis. In this context, new cardiovascular toxicities related to new drugs have emerged. We are now compelled to respond to cardiovascular adverse events despite the lack of evidence regarding optimal management. The result has been establishment and rapid maturation of the new academic field of cardio-oncology. Despite the relative lack of evidence, we must review small pieces of evidence that have accumulated to date and make the utmost efforts to provide patients with effective evidence-based medical care. Simultaneously, we urgently need randomized clinical trials to build strong evidence.

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Cardiotoxicities of 5-Fluorouracil and Other Fluoropyrimidines

Takotsubo syndrome, also known as stress-induced cardiomyopathy (SC), is underrecognized in cancer patients. This study aims to investigate the incidence, natural history, and triggers of SC in cancer patients and its impact on cancer therapy and overall survival. A total of 30 subjects fulfilled the diagnostic criteria for SC at MD Anderson Cancer Center over a 6-year period. Clinical presentation, electrocardiogram, laboratory data, and transthoracic echocardiogram results registered during the acute phase and follow-up were collected. All patients underwent coronary angiography. The most frequent presenting symptoms were chest pain in 63.3% of the patients and shortness of breath/dyspnea on exertion in 27% of the patients. T-wave inversion was a more common electrocardiographic presentation (60%) than ST elevation (13.3%). The median and interquartile range of peak creatine kinase MB fraction, troponin I, and brain natriuretic peptide were creatine kinase MB fraction 8.9, 4.6 to 21.1; troponin I 1.31, 0.7 to 3.3; and brain natriuretic peptide 1,124, 453.5 to 2,369.5. The most common complication of SC was cardiogenic shock requiring inotropic agents (20%). Of the 21 patients who required ongoing cancer treatment, 16 were able to resume chemotherapy, 5 underwent surgery, and 4 received radiation treatment. Median time to resume cancer treatment was 20 days after SC. None of the patients experienced recurrence of SC and other cardiac events. In conclusion, SC should be considered in the differential diagnosis of cancer patients who present with chest pain and ECG findings characteristic of acute coronary syndrome. Most of these patients normalize ejection fraction and may resume cancer therapy early.

Stress-Induced Cardiomyopathy in Cancer Patients.

Takotsubo cardiomyopathy is a rare but increasingly recognized phenomenon, which can occur as a side-effect of chemotherapeutic agents, in particular, the antimetabolite 5-fluorouracil. We describe a case of delayed Takotsubo cardiomyopathy after 3 weeks of adjuvant 5-fluorouracil for resected rectal adenocarcinoma in a 66-year-old female, supported by angiographic, electrocardiographic, and echocardiographic features. As a complication, she developed an apical mural thrombus with subsequent cerebral thromboembolic events and was successfully anticoagulated to make a full recovery. We present a review of the literature on Takotsubo cardiomyopathy secondary to 5-fluorouracil and the rare occurrence of thromboembolic complications. As this is a significant clinical phenomenon which involves a multispeciality approach to management, oncologists and cardiologists need to recognize it as a potential toxicity of a widely administered chemotherapeutic drug.

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Takotsubo Cardiomyopathy and 5-Fluorouracil: Getting to the Heart of the Matter

Aims The aim of this study was to evaluate whether a real-time (RT) colour pictorial radiation dose monitoring system reduces patient skin and total radiation dose during coronary angiography and intervention. Methods and results Patient demographics, procedural variables and radiation parameters were recorded before and after institution of the RT skin dose recording system. Peak skin dose as well as traditionally available measures of procedural radiation dose were compared. A total of 1,077 consecutive patients underwent coronary angiography, of whom 460 also had PCI. Institution of the RT skin dose recording system resulted in a 22% reduction in peak skin dose after accounting for confounding variables. Radiation dose reduction was most pronounced in those having PCI but was also seen over a range of subgroups including those with prior coronary artery bypass surgery, high BMI, and with radial arterial access. This was associated with a significant reduction in the number of patients placed at risk of skin damage. Similar reductions in parameters reflective of total radiation dose were also demonstrated after institution of RT radiation monitoring. Conclusions Institution of an RT skin dose recording reduced patient peak skin and total radiation dose during coronary angiography and intervention. Consideration should be given to widespread adoption of this technology.

Sharon Wilson

Papers

Takotsubo Cardiomyopathy and 5-Fluorouracil: Getting to the Heart of the Matter

Real-time colour pictorial radiation monitoring during coronary angiography: effect on patient peak skin and total dose during coronary angiography.