Current first-line therapy for acute myeloid leukemia (AML) involves a regimen of anthracycline-based induction chemotherapy. Cardiotoxicity is a rare but serious complication of such regimens and although it is a well-established phenomenon there is minimal evidence to inform the optimal frequency or nature of cardiac monitoring in these patients.
The Ottawa Hospital measures baseline ejection fraction in all AML patients potentially eligible for induction chemotherapy. In this chart review we evaluated the effectiveness of this practice by weighing the clinically relevant information obtained from this testing against its costs and its potential to delay therapy.
Electronic charts of all patients admitted to the Ottawa Hospital with a primary diagnosis of AML between January 2009 and March 2012 were included for review. Charts were excluded only if initial AML management pre-dated 2009 or occurred at other institutions. We sought to: 1. Determine to what extent cardiac function testing delays chemotherapy administration and 2. Assess the utility of cardiac function testing by a) determining if pre-test risk factor profiles were predictive of abnormal cardiac function, and b) quantifying the instances in which cardiac function testing results altered management. To address these objectives data regarding timing from AML diagnosis to cardiac function testing and induction, individual cardiac risk factor profiles and cardiac function test results, and reasons for deciding against induction chemotherapy were extracted from all included electronic charts and analyzed.
A total of 124 patient charts were included for review. Median patient age was 61 (range 18–97) and patents were more often male (62%). Approximately two thirds (65%) were induced. Patients had a median of two cardiac risk factors (mean 2.3 +/− 1.7), the most common of which were age over 60 (59%), smoking (52%), and obesity (36%). A majority of patients (92, 74%) had cardiac function testing performed, 43 (47%) of which were echocardiograms and 47 (53%) of which were multigated acquisition scans (MUGAs).
For patients in whom AML was diagnosed on admission, a bone marrow aspirate was performed within a median of one day. It took a median two days to complete cardiac function testing. Induction proceeded within one day of completion of cardiac function testing in 40 patients (75%) and on the same day in 22 patients (42%). Time courses for patients who were diagnosed with AML prior to admission were shorter than those diagnosed after admission but reflected a similar pattern.
Cardiac function tests were available for 92 patients and 4 abnormal results were documented. There were no instances in which results of cardiac function testing lead to changes in dosing or cancellation of planned induction therapy.
Patients with abnormal baseline cardiac function tended to have more risk factors than those with normal cardiac function (3.3 +/− 1.3 vs 2.1 +/− 1.7) but this difference was not statistically significant (p = 0.217). Of note 41% of those with normal cardiac function had fewer than two risk factors, while none of those with abnormal cardiac faction met this cutoff.
The clinical utility of baseline cardiac function testing in our population of AML patients is questionable. Of 124 patients, abnormal results were rare (3%) and in no instances did these results change management decisions. Cardiac risk factor profiles were not significantly predictive of abnormal cardiac function, but given the rarity of abnormal results in our population it is difficult to draw conclusions from this data. Cardiac function testing ultimately lead to a delay in induction by an estimated median of 2 days. Given the cost and resources used for cardiac function testing (estimated $200–300/test), the additional hospital days spent waiting for its completion (estimated $1,500/day), its potential to delay the administration of emergent induction chemotherapy, and its non-contribution to management decisions, this chart review puts into question the necessity of baseline cardiac function testing in newly diagnosed AML patients. These conclusions merit broader exploration in other centers and patient populations.
No relevant conflicts of interest to declare.
Asterisk with author names denotes non-ASH members.