The study sought to determine the utility of dobutamine stress echocardiography (DSE)
in predicting cardiac events in the year after testing.
Increasingly, DSE has been applied to risk stratification of patients.
Medical records of 1,183 consecutive patients who underwent DSE were reviewed. The
cardiac events that occurred during the 12 months after DSE were tabulated: myocardial
infarction (MI), cardiac death, percutaneous transluminal coronary angioplasty (PTCA),
and coronary artery bypass surgery (CABG). Patient exclusions included organ transplant
receipt or evaluation, recent PTCA, noncardiac death, and lack of follow-up. A positive
stress echocardiogram (SE) was defined as new or worsened wall-motion abnormalities
(WMAs) consistent with ischemia during DSE. Classification and regression tree (CART)
analysis identified variables that best predicted future cardiac events.
The average age was 68+/-12 years, with 338 women and 220 men. The overall cardiac
event rate was 34% if SE was positive, and 10% if it was negative. The event rates
for MI and death were 10% and 8%, respectively, if SE was positive, and 3% and 3%,
respectively, if SE was negative. If an ischemic electrocardiogram (ECG) and a positive
SE were present, the overall event rate was 42%, versus a 7% rate when ECG and SE
were negative for ischemia. Rest WMA was the most useful variable in predicting future
cardiac events using CART: 25% of patients with and 6% without a rest WMA had an event.
Other important variables were a dobutamine EF <52.5%, a positive SE, an ischemic
ECG response, history of hypertension and age.
A positive SE provides useful prognostic information that is enhanced by also considering
rest-wall motion, stress ECG response, and dobutamine EF.