A 34-year-old woman is admitted with a diagnosis of acute lymphoblastic leukemia (ALL). She is scheduled to receive induction chemotherapy with vincristine, doxorubicin, and prednisone. She has no other past medical history. She has never smoked or used recreational drugs. Which of the following tests is the most appropriate for monitoring this patient's condition while on chemotherapy?

Question

A 34-year-old woman is admitted with a diagnosis of acute lymphoblastic leukemia (ALL).  She is scheduled to receive induction chemotherapy with vincristine, doxorubicin, and prednisone.  She has no other past medical history.  She has never smoked or used recreational drugs.  Which of the following tests is the most appropriate for monitoring this patient's condition while on chemotherapy?

Quizplus · Accepted Answer

Explanation: Cardiotoxicityis one of the primary concerns when administering anthracycline chemotherapy agents, such as doxorubicin and daunorubicin. The risk of cardiotoxicity with these agents is related to the cumulative dose, and is increased in patients with preexisting cardiac disease with a low ejection fraction (EF). In the general population, resting echocardiography is often used to evaluate EF but there is potential for significant variability in the results. Radionuclide ventriculography, also known as a MUGA (multigated acquisition) scan, is typically used to monitor patients receiving cardiotoxic chemotherapy as it is a highly accurate and reproducible test for quantitating left ventricular EF. A radionuclide ventriculogram is generally performed at baseline before chemotherapy is initiated, and before each subsequent dose of chemotherapy. The therapeutic regimen is dependent on the baseline cardiac function (eg, anthracycline chemotherapy contraindicated with baseline EF <30%, modified dosing required with baseline EF <50%). A decrease in the EF by ≥10 percentage points may warrant discontinuation of therapy. (Choice A) Ambulatory 24-hour ECG monitoring is most useful when there is suspicion for an intermittent arrhythmia, for example, in patients being evaluated for syncope. (Choice B) Anthracycline chemotherapy agents may worsen the EF by a direct toxic effect on the myocardium. Patients with coronary artery disease may have an increased risk of cardiotoxicity if they have a low baseline EF, but this is secondary to the preexisting myocardial damage as opposed to the coronary artery disease itself. (Choice C) Cardiac troponins may be elevated in patients with myocardial damage from doxorubicin. This may one day be used as a monitoring test, but at the present time there is insufficient evidence to support its clinical use in the above described context. (Choice E) Stress myocardial perfusion imaging is used to stratify patients at risk of having coronary artery disease. However, accurate measurement of the EF is the most important and classically used test for evaluating and following patients receiving cardiotoxic chemotherapy. Educational objective: Radionuclide ventriculography has high accuracy and reproducibility for measuring ejection fractions. Its most common use is in the initial evaluation and subsequent follow-up of patients receiving cardiotoxic chemotherapy agents such as doxorubicin.

A 34-Year-Old Woman Is Admitted with a Diagnosis of Acute