A Clinical and Echocardiographic Score for Assigning Risk of Major Events After Dobutamine Echocardiograms JACC Vol. 43, No June 2, 2004:2102–7 Brisbane, Australia; Rotterdam, Netherlands; Indianapolis, Indiana; and Cleveland, Ohio

Background Functional testing  Predict outcomes  Cost-effective approaches to the treatment of coronary artery disease (CAD)  Stress testing in the recent American College of Cardiology /American Heart Association guidelines Multivariate scores  Disease probability & outcome Exercise testing scores + Clinical data  greater prognostic power

Cardiac stress imaging  Inability to exercise  Resting ST-segment change Dobutamine stress echocardiography  Independent & incremental predictor of adverse outcome  No scores analogous

further investigation and management Clinical Finding Echocardiographic findings Prognostic score patients undergoing DbE as their primary test

Methods Patient selection.  Two high-volume echocardiography laboratories in the U.S. (Cleveland Clinic Foundation and Indiana University Hospital)  Thoraxcenter (Rotterdam, the Netherlands).  Suspected CAD, and clinical data, stress test findings and echocardiographic data In the U.S. Before noncardiac surgery (37%) Risk evaluation after infarction (23%) Evaluation of chest pain (17%) Known CAD ( 30%) Previous MI ( 23%) Revascularization ( 6% ) In the Dutch group Preoperative cardiac risk assessment (42%) Diagnostic reasons (41%) After infarction (21%).

Stress testing  Dobutamine testing in the usual fashion  Standard end points Severe ischemia (severe angina, 2-mm St segment depression) Hypertension ( systolic blood pressure 220 mm Hg ) Hypotension ( decrement of systolic blood pressure to 100 mm Hg or with symptoms) Arrhythmia  Angina, ST-segment depression, magnitude of ST-segment depression  Record

Echocardiography  Standard two-dimensional echocardiography : rest and after stress  resting left ventricular (LV) function : normal or abnormal  Regional dysfunction : resting akinesia / severe hypokinesia  the existence of “scar”  Ischemia : new or worsening wall motion abnormalities  The extent of ischemia : territories of the three coronary arteries

Modeling and validation groups Calculation of a risk score  five-year event-free survival rates of 95%,75% to 95%, and 75%  low-, intermediate-, high-risk The classification of the Duke treadmill score Statistical analysis

Figure 1. Distribution of patients and events into the modeling and internal validation groups for dobutamine echocardiography.

Table 1. Clinical,Stress,and Echocardiographic Variables in the Dobutamine Echocardiography Groups There were no differences between the modeling and internal validation groups. The external validation group showed significantly fewer risk factors and a lower rate-pressure product, but more scar and ischemia (*p 0.01, †p 0.001). Data are presented as the mean value SD or number (%) of subjects.

Table 2. Independent Predictors of Events by Dobutamine Echocardiography in the Modeling Group CI confidence interval; DbE dobutamine echocardiogram; LV left ventricular; RR relative risk

Table 3. Relationship of Dobutamine Score With Outcome Risk = (age · 0.02) + ( heart failure history + rate-pressure product <15,000) · (ischemia + scar ) · 0.6

Figure 2. Outcomes of high-, intermediate-, and low-risk groups in the modeling (A) and internal validation (B) groups undergoing dobutamine echocardiography.

Figure 3. Outcomes of high-, intermediate-, and low-risk groups in the external validation group undergoing dobutamine echocardiography.

Discussion Prognostic implications of stress imaging tests.  Stress test Negative / positive  the clinical setting No easy way of integrating these data  These simple scores (small number of variables)  more powerful !

Clinical application of score results. patient’s abnormal result + clinical markers of risk  Important predictor of high risk  Useful in facilitating decision-making regarding revascularization.

Study limitations  “decision-making was likely colored by the test Results.” The test results  further investigation  revascularization decisions The risk associated with a positive test : underestimate ( as the performance of revascularization ) Observational study Large follow-up trial with the ordering physicians’ results blinded to the final results

Conclusion The prognostic scores in this study  Clinical decision-making in patients with known or suspected CAD, based on an individualized assessment of risk.