A clinical and echocardiographic score for assigning risk of major events after dobutamine echocardiograms

Objectives We sought to develop and validate a risk score combining both clinical and dobutamine echocardiographic (DbE) features in 4,890 patients who underwent DbE at three expert laboratories and were followed for death or myocardial infarction for up to five years. Background In contrast to exercise scores, no score exists to combine clinical, stress, and echocardiographic findings with DbE. Methods Dobutamine echocardiography was performed for evaluation of known or suspected coronary artery disease in 3,156 patients at two sites in the U.S. After exclusion of patients with incomplete follow-up, 1,456 DbEs were randomly selected to develop a multivariate model for prediction of events. After simplification of each model for clinical use, the models were internally validated in the remaining DbE patients in the same series and externally validated in 1,733 patients in an independent series. Results The following score was derived from regression models in the modeling group (160 events): DbE risk = (age·0.02) + (heart failure + rate-pressure product <15,000)·0.4 + (ischemia + scar)·0.6. The presence of each variable was scored as 1 and its absence scored as 0, except for age (continuous variable). Using cutoff values of 1.2 and 2.6, patients were classified into groups with five-year event-free survivals >95%, 75% to 95%, and <75%. Application of the score in the internal validation group (265 events) gave equivalent results, as did its application in the external validation group (494 events, C index = 0.72). Conclusions A risk score based on clinical and echocardiographic data may be used to quantify the risk of events in patients undergoing DbE.

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