Maurizio Mazzoni

Predictive value of EuroSCORE on long term outcome in cardiac surgery patients: a single institution study

Objectives: To assess the value of the European system for cardiac operative risk evaluation (EuroSCORE), a validated model for prediction of in-hospital mortality after cardiac surgery, in predicting long term event-free survival. Design and setting: Single institution observational cohort study. Patients: Adult patients (n  =  1230) who underwent cardiac surgery between January 2000 and August 2002. Results: Mean age was 65 (11) years and 32% were women. Type of surgery was isolated coronary artery bypass grafting in 62%, valve surgery in 23%, surgery on the thoracic aorta in 4%, and combined or other procedures in 11%. Mean EuroSCORE was 4.53 (3.16) (range 0–21); 366 were in the low (0–2), 442 in the medium (3–5), 288 in the high (6–8), and 134 in the very high risk group (⩾ 9). Information on deaths or events leading to hospital admission after the index discharge was obtained from the Regional Health Database. Out of hospital deaths were identified through the National Death Index. In-hospital 30 day mortality was 2.8% (n  =  34). During 2024 person-years of follow up, 44 of 1196 patients discharged alive (3.7%) died. By Cox multivariate analysis, EuroSCORE was the single best independent predictor of long term all cause mortality (hazard ratio (HR) 1.55, 95% confidence interval (CI) 1.03 to 2.34, p < 0.0001). In the time to first event analysis, 227 either died without previous events (n  =  20, 9%) or were admitted to hospital for an event (n  =  207, 91%). EuroSCORE (HR 1.60, 95% CI 1.36 to 1.89, p < 0.0001), the presence of ⩾ 2 co-morbidities versus one (HR 1.49, 95% CI 1.09 to 2.02, p < 0.0001), and > 96 hours’ stay in the intensive care unit after surgery (HR 2.04, 95% CI 1.42 to 2.95, p  =  0.0001) were independently associated with the combined end point of death or hospital admission after the index discharge. Conclusions: EuroSCORE and a prolonged intensive care stay after surgery are associated with long term event-free survival and can be used to tailor long term postoperative follow up and plan resource allocation for the cardiac surgical patient.

Myocardial lactate metabolism in relation to preoperative regional wall motion and to early functional recovery after coronary revascularization

OBJECTIVE To evaluate myocardial lactate metabolism as a marker of functional status after surgical coronary revascularization. DESIGN Single-center, prospective, cohort study. SETTING Tertiary care teaching hospital. PARTICIPANTS Fifty patients with stable angina, ejection fraction >0.40, undergoing coronary artery bypass surgery for multiple-vessel disease. MEASUREMENTS AND MAIN RESULTS Before (T1) and 30 minutes (T2) after coronary artery bypass grafting, the authors simultaneously sampled blood from artery and coronary sinus to determine myocardial lactate dynamics and performed transesophageal echocardiography (TEE) to assess segmental wall motion. Wall motion score index (WMSI) was calculated with an online/offline comparison. At T2, WMSI improved from 1.40 +/- 0.31 to 1.17 +/- 0.23 (p = 0.0001). Preoperatively, 2 patterns of lactate balance were found: 39 patients were lactate extractors (17% +/- 10%) and 11 were lactate producers (-11% +/- 11%). At T2, lactate metabolism was shifted towards a pattern opposite to the baseline: delta lactate extraction was -8% +/- 16% in extractors at T1 versus 7% +/- 9% in producers at T1 (p = 0.003). Changes in WMSI were not correlated with changes in lactate utilization. No single preoperative variable predicted postoperative WMSI or its changes from baseline. Cardiopulmonary bypass (CPB) time was the only significant predictor of postoperative lactate extraction by multivariate regression (r = -0.46, p = 0.001): at T2, patients in the highest CPB time quartile showed frank lactate production (-6% +/- 13%) when compared with those in the lowest quartile (15% +/- 11%, p = 0.005). However, postoperative WMSI was similar in different CPB time groups. CONCLUSIONS Myocardial lactate metabolism pattern is not associated with functional status before and early after successful coronary revascularization. CPB time was the only significant predictor of postoperative lactate extraction. Measurement of lactate does not appear to be a valuable tool to assess the coupling of myocardial regional function and metabolism in the setting of coronary artery surgery and mild-to-moderate functional impairment.