A new marker of risk for ischemic events

Type of funding sources: None.

Although dobutamine stress echocardiography (SE) has a high specificity, there is still a subset of patients (P) with false positive tests (FP) and their prognosis remains unclear.

To identify the clinical and echocardiographic predictors of FP on SE and to evaluate the prognostic impact of FP on SE.

Retrospective study of 355 consecutive adult P who underwent SE for ischemia assessment over a one-year period: 134 (37,7%) women, 70,3 ± 0,57 years, body surface area (ASC) 1,85±0,01 cm2. Demographics, risk factors, clinical and laboratorial parameters and SE variables were evaluated. A FP result was defined as a positive SE for ischemia in the absence of ≥50% coronary artery (CA) lesion in a major artery of the corresponding coronary territory on subsequent angiography. P were divided into 2 groups regarding the presence (FP+) or the absence (FP0: 15,5% true positives, 79,7% true negatives, 0,3% false negatives ) of a FP result on SE and a comparative analysis was performed in order to characterize the groups and identify potencial predictors of FP results. P were followed for 2 years to assess acute myocardial infarction (AMI), hospitalization for acute heart failure (HF) and mortality (M).

The FP rate was 4,5% (16P). Comparing to F0, P in group FP+ were younger (65,1±2,4 vs 70,5±0,6 years; p=0,045), baseline wall motion abnormalities were more frequent (75,0% vs 41,6%; p=0,009), had higher mean blood pressure values at rest (99,3±5,4 vs 82,0±1,3 mmHg; p=0,004) and at peak stage (140,3±5,6 vs 102,8±2,3 mmHg; p<0,001) and more often hypertensive response (37,5% vs 7,1%; p<0,001). There were no significant differences regarding previous CA disease, medication or complete left bundle branch block. By multivariate analysis, only mean blood pressure values at rest (OR 0,01; 95%CI 0,005-0,02; p=0,003) and at peak stage (OR 0,02; 95%CI 0,000-0,004; p=0,003) were independente predictors of FP. During follow-up was observed: AMI (FP+: 12,5% vs FP0: 1,8%, p=0,046), HF (FP+: 6,3% vs FP0: 11,5%, p=0,44) and M (FP+: 6,3% vs FP0: 6,2%, p=0,65). After adjustment for age, sex and comorbidities, there were no diferences between the groups regarding HF (p=0,45) and M (p=0,77), but the group FP+ mantained a higher rate of AMI (OR 0,21; 95%CI 0,065-0,354; p=0,005).

A FP result on SE is associated with higher mean blood pressure values during the test and with higher rates of AMI during follow-up. This result on SE should therefore be faced as a risk marker for ischemic events and can identify P that may benefit from aggressive risk factor control and careful clinical follow-up.