Abstract

ZAPATA, GERARDO O.; LOPEZ, JORGE; HOMINAL, MIGUEL  and  CANDELL-RIERA, JAUME. Prognostic Value of Infarct size Measured by Gated sPECT scintigraphy. Rev. argent. cardiol. [online]. 2015, vol.83, n.6, pp.1-8. ISSN 1850-3748.

Background: Despite the improved sensitivity and specificity of SPECT myocardial perfusion imagingto detect myocardial involve-ment after acute myocardial infarction (AMI), there is little information about the usefulness of early infarct size (IS) measurement by this method for risk stratification and prognosis. Objectives: The goal of this study was to evaluate the usefulness of quantifying IS by gated SPECT scintigraphy to predict cardio­vascular events in patients with a first AMI. Methods: Patients with a first ST-segment elevation AMI were included from 2009 to 2014. Infarct size was estimated using the Cedars QPS software. The incidence of events (heart failure, ventricular arrhythmias, mortality and a composite of the three events) was evaluated at one year. Results: One-hundred and forty nine patients were included in the study; mean age was 59±11 years and 81.9% were men. Diabetes was present in 16.1% of cases, 9.4% had a history of myocardial revascularization, 84.6% were admitted in Killip and Kimball class A, 43% of AMIs were located in the anterior wall and 69.8% of the patients underwent reperfusion. Left ventricular ejection fraction estimated by gated SPECT scintigraphy was 51%±14%. Follow-up was completed in 95.9% of cases. An IS cutoff point of 22% (ROC curve) was established to predict the composite endpoint at follow-up (sensitivity 92%, specificity 81%, AUC: 0.94%), dividing the sample into two groups: Group I (IS <22%) and Group II (IS ≥22%). The prevalence of the composite endpoint was greater in Group II (2.1% Group I vs. 50% Group II; p<0.001). Infarct size ≥ 22% was the only variable identified as predictor of events during follow-up (OR 1.978; 95% CI 1.887-1.996; p<0.001). Conclusion: Early quantification of IS by gated SPECT scintigraphy is an independent risk predictor at one year that allows risk stratification in patients with a first AMI.

Keywords : Myocardial Infarction/physiopathology - Cardiac Gated Single-photon Emission Computer Assisted Tomography - Prog­nosis.

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