Imaging the heart in the cancer patient

Abstract

The average age of a cancer patient is 67. Sexagenarians with cancer are likely to have comorbidities at the time of diagnosis. Cancer patients > 55 years old have an average of ~2.9 comorbidities, while cancer patients older than 75 have an average of 4.2 comorbidities. The likelihood of coronary artery disease as an etiology of this comorbidity increases with the age of the patient. Cardiovascular comorbidity is present in ~20% of patients with neoplasm. These comorbidities increase the risk of a serious cardiovascular event during treatment. An additional risk factor is limited work capacity. If patients cannot perform 4 metabolic equivalents of work, their all cause mortality is increased. Patients with cancer and known cardiovascular comorbidity or risk factors such as diabetes, hypertension, smoking history, or limitedworkcapacity shouldhavemedical clearance prior to invasive diagnostic procedures, major surgery, mediastinal radiation, and/or potentially cardiotoxic chemotherapy. Medical clearance should include a detailed cardiovascular history and physical examination. This information will permit calculation of a clinical score to define the risk of adverse events as a result of a major surgical procedure, blood tests to determine hematologic and renal status, and if necessary, assessment of the patients work capacity. Stress testing with imaging should be done in patients with an intermediate risk of coronary heart disease and considered in patients with limited work capacity or advanced age. In selected patients, coronary CT angiography or coronary calcium score may be a suitable evaluation. In patients with cancer of the esophagus, breast, lung, melanoma, or lymphoma, chest-CT and PET/ CT studies should be carefully evaluated to detect possible pericardial or myocardial involvement. Chemotherapy may cause myocardial ischemia due to coronary spasm and decreased ventricular function due to irreversible or reversible myocardial damage, as well as repolarization abnormalities, which may result in fatal arrhythmia. Radiotherapy may accelerate the development of atherosclerosis of vessels in the radiation field and cause irreversible damage to myocardium in the radiation field. Myocardial perfusion imaging is useful to detect regions of acute ischemia or scar induced by therapy, while blood pool imaging is useful for serial monitoring of ventricular function.