Aims: Poor image quality remains a limitation of dobutamine stress echocardiography (DSE). This study aimed at investigating the effects of transpulmonary contrast application on endocardial border delineation and diagnostic yield of DSE in patients with intermediate coronary stenoses. The invasively measured fractional flow reserve (FFR) served as the reference standard.
Methods and results: Seventy patients with an intermediate coronary stenosis entered the study. Cineloops were recorded during DSE before and after contrast application at rest and peak stress. Two observers blinded to angiography assessed wall motion. FFR was measured in the target vessel during repeat angiography and an FFR <or= 0.75 was considered pathological. Abnormal FFR findings were seen in 41% of the patients. Native DSE was abnormal in 36% and contrast-enhanced DSE in 50% of the patients. Luminal diameter narrowing measured by quantitative angiography was not significantly different between patients with normal and abnormal FFR. After contrast application, the number of non-interpretable segments [median (25-75th percentile)] decreased from 2 (1-3) to 0 (0-0) at rest and from 1 (0-3) to 0 (0-0) at stress (both P < 0.001). Compared with native imaging, sensitivity and accuracy increased with transpulmonary contrast from 48 [CI (confidence interval) 40-57%] to 83% (76-91%) and from 62 (CI 56-69%) to 77% (71-82%), respectively (both P = 0.05).
Conclusion: Transpulmonary contrast application improves the interpretability and diagnostic yield of DSE in patients with intermediate coronary lesions.