Cardiac imaging improves risk stratification in high-risk patients undergoing surgical revascularization

In patients with ischaemic left ventricular dysfunction, multivessel disease and dominance of necrotic myocardium, perioperative mortality due to coronary artery bypass grafting is still a rather unclear issue. The aim of this study was to analyse the impact of different imaging variables in predicting perioperative mortality.

We selected a group of 259 patients who had preoperatively been defined as 'high-risk patients' and who showed a mostly necrotic myocardium as detected by thallium-201 myocardial scintigraphy.

Mean ejection fraction was 0.26 +/- 0.07. In a 16-segment model, the mean number of scintigraphic necrotic myocardial segments was 5.07 +/- 1.09, echocardiographic end-diastolic diameter was 29.41 +/- 2.38 mm/m2 and wall motion score index was 2.29 +/- 0.19. Perioperative mortality increased along with the increase in the number of necrotic segments: 5/105 (5%), 4/63 (6%), 8/52 (15%) and 8/39 (20%) patients with four, five, six and seven necrotic segments, respectively. The analysis of additional variables in survived vs. deceased patients demonstrated a significant difference in echocardiographic end-diastolic diameter (27 +/- 8 vs. 31.9 +/- 1.9 mm/m2, P < 0.001) and in wall motion score index (2.2 +/- 0.1 vs. 2.4 +/- 0.2, P < 0.001).

In high-risk patients, the extension of scintigraphic myocardial scar has a significant impact on perioperative mortality. For similar values of ejection fraction at rest, additional imaging variables, such as echocardiographic end-diastolic diameter and wall motion score index, may contribute to select those patients in whom mortality may exceed 15%.