14. Intraoperative hemodynamics and mortality following coronary artery bypass surgery

The modulation of sympathetic responses and rigorous intraoperative hemodynamic control has never been proven to decrease perioperative cardiac morbidity (Anesthesiology 1990; 72:153- -84). The purpose of the current study is to determine whether intraoperative hemodynamic instability was associated with death in a cohort of patients undergoing coronary artery bypass grafting (CABG). Methods: The study was institutionally approved. Risk factors and outcomes were queried from a New York State-mandated database. Intraoperative hemodynamic lability was measured (using a validated algorithm) from computerized anesthesia records that recorded data every 15 seconds. In addition, the number of minutes a patient was exposed to moderate and severe extremes of various hemodynamic variables (e.g., mean arterial pressure <50 or > 130 mm Hg) was tabulated. Univariate tables and multivariate logistic regression were used to identify predictors of perioperative death. Results: There were 687 patients and 20 perioperative deaths. All of the deaths occurred in patients undergoing urgent or emergent surgery (n=421), and all had Canadian Cardiovascular Surgery functional status III or IV. The predictors of death are summarized in the table 1. The hemodynamic variables were not independent (multivariate) predictors of death. Conclusions: The presumption that smooth intraoperative hemodynamics are associated with improved outcome has never been demonstrated. The data in the current cohort of patients do not support the concept that intraoperative hemodynamic instability is an independent predictor of mortality. Table 1 Univariate and multivariate analysis of risk of mortality Univariate Multivariate Multivariate Univariate P-value Odds Ratio P-value P-value Demographics Ventricular Dysfunction Age > 75 years 0.14 2.4 0.10 Eject fraction > 40% 0.07 Black race 0.16 Hemodyn instability 0.001 Diabetes 0.009 2.9 0.04 Renal failure <0.001 15.4 0.0003 Intraoperative Data Pre-CPB COPD 0.01 4.7 0.04 DPAPhigh 0.06 Fresh MI 0.05 3.4 0.08 MPAPhigh 0.13 > 1 Previous MI 0.10 HR very high <0.001 Vascular Disease Intraoperative Data Post-CPB RCA/PDA > =50% 0.12 HR high 0.01 Perip Vase Diasease 0.002 2.8 0.04 MPAP high 0.009 LVHbyECG 0.003 DPAPhigh 0.013 Calcified Asc Aorta 0.15 Abbreviations: COPD - chronic obstructive pulmonary disease; MI - myocardial infarction; RCA - right coronary artery; PDA - posterior descending coronary artery; ECG - electrocardiographic; LVH - left ventricular hypertrophy; DPAP - diastolic pulmonary artery pressure; CPB - cardiopulmonary bypass; MPAP - mean pulmonary artery pressure; HR - heart rate; MAP - mean arterial pressure.