Preoperative risk stratification using stress myocardial perfusion scintigraphy with electrocardiographic gating

This study was designed to assess the prognostic value of stress myocardial perfusion SPECT with electrocardiographic (ECG) gating in patients undergoing noncardiac surgical treatment.

The study included 481 consecutive patients who underwent noncardiac surgery and had been referred for preoperative myocardial perfusion scintigraphy. Myocardial scintigraphy used (99m)Tc-labeled perfusion agents and dipyridamole stress with ECG gating, permitting qualitative and quantitative analyses of both myocardial perfusion and cardiac function. Reconstructed perfusion images were analyzed qualitatively and semiquantitatively. The Quantitative Gated SPECT (QGS) program was used for gated SPECT analysis to calculate global left ventricular ejection fraction and estimate regional wall motion. We assessed the relationships between perioperative cardiac events and various predictors, including clinical risk factors, radionuclide perfusion, and functional variables.

Univariate analysis indicated that age (P < 0.001), diabetes mellitus (P < 0.01), history of heart failure (P < 0.05) or perfusion imaging (P < 0.0001), and QGS analysis (P < 0.0001) yielded significant risk stratification. According to multivariate analysis, age, diabetes mellitus, perfusion imaging, and QGS analysis were independent predictors of perioperative cardiac events. The event rate was correlated with quantitative scintigraphic indices of perfusion images (rest perfusion and ischemic scores) and QGS analysis (global ejection fraction and the number of hypokinetic segments). Although QGS functional data offered no significant incremental prognostic value in patients with abnormal perfusion, it classified patients with normal perfusion into 2 risk groups (P < 0.0001). A combination of clinical risk factors, scintigraphic perfusion results, and functional data allowed further detailed risk stratification.

Stress myocardial perfusion SPECT with ECG gating has an incremental prognostic value over conventional nongated stress perfusion imaging in predicting perioperative cardiac events.