2007 HSR&D National Meeting Abstract
3105 — Levels of Preoperative Hematocrit Predict Postoperative Cardiovascular and Fatal Outcomes in Elderly Patients Undergoing Major Non-Cardiac Surgery
Wu WC (Providence VAMC) , Schifftner TL
(Denver VAMC), Henderson WG
(University Colorado), Eaton CB
(Memorial Hospital of Rhode Island), Poses RM
(Brown University), Uttley G
(Providence VAMC), Sharma SC
(Providence VAMC), Vezeridis M
(Providence VAMC), Khuri SF
(Boston VAMC), Friedmann PD
Elderly patients are at high risk for both abnormal hematocrit values and cardiovascular complications of non-cardiac surgery. Despite nearly universal testing of hematocrit values prior to major surgery, the prognostic implications of preoperative anemia or polycythemia are incompletely understood for this high risk population. We studied the relationship between preoperative anemia and polycythemia, and postoperative outcomes in elderly patients undergoing non-cardiac surgery using the VA National Surgical Quality Improvement Program (NSQIP).
We conducted a retrospective study of 310,311 veterans 65 years or older who underwent major non-cardiac surgery between 1997 and 2004 in 132 Veterans Affairs Medical Centers across the United States. Based on preoperative hematocrit levels, we stratified patients into standard categories of anemia (hematocrit less than 39.0 percent), normal hematocrit (39.0 to 53.9 percent), and polycythemia (hematocrit of 54 percent or greater). We then estimated increases in 30-day postoperative cardiac event and mortality risks in relation to each hematocrit point deviation from the normal category.
Thirty-day mortality and cardiac event rates increased monotonically with either positive or negative deviations from normal hematocrit levels. We found a 1.6 percent (95 percent confidence interval, 1.1 to 2.2 percent) increase in 30-day postoperative mortality associated with every hematocrit point increase or decrease from the normal preoperative hematocrit range. More detailed analyses suggest that the adjusted risk of 30-day postoperative mortality and cardiac morbidity begin to rise when hematocrit levels fall below 39 percent or exceed 51 percent.
Even mild degrees of preoperative anemia or polycythemia confer a significant risk for 30-day postoperative mortality in elderly veterans undergoing major non-cardiac surgery.
Our results justify the need for preoperative hematocrit testing in elderly patients undergoing major surgery and highlight potential areas of intervention to improve the preoperative risk of elderly patients.