Relevance of early poststress variation in left ventricular function studied by gated-SPECT: evaluation in different clinical settings and relationship with angiography results.

Background: Stress-induced ischemia may cause a decrease in left ventricular ejection fraction (EF). We evaluated the variation in early postexercise EF (S-EF) compared with rest EF (R-EF) in different clinical settings to detect ventricular dysfunction. We also correlated ventricular dysfunction with an angiographic score, the Syntax score, in a subgroup of ischemic patients.

Materials And Methods: Gated-SPECT images were acquired 12 min after exercise stress and at rest in 1481 patients. Patients were classified as controls, negative for ischemia, mildly ischemic, moderately/severely ischemic, necrotic, and necrotic with ischemia. Mean end-diastolic volume, end-systolic volume, and EF were compared in each group. The ratio between stress to rest EF was indicated as the functional score. Angiography results were collected for 55% of moderately/severely ischemic patients. Sixty-one angiographies were also completed with Syntax score evaluation.

Results: In negative, necrotic, and mildly ischemic patients no differences were found between S-EF and R-EF. An opposite trend was observed in moderately/severely ischemic patients with a decrement of S-EF compared with R-EF (54.80±11.33 vs. 57.79±11.14; P<0.0001). Coronary artery disease was confirmed by angiography in 93% of moderately/severely ischemic patients. In 61 patients who underwent Syntax score evaluation, significant correlation was observed with functional score. Significant decrease in functional score was found in patients with coronary artery bypass graft indication compared with patients with percutaneous coronary intervention or medical indication.

Conclusion: Early poststress gated-SPECT acquisition allows the detection of ventricular dysfunction in moderately/severely ischemic disease and provides additional information when directing patients to angiography and revascularization.