A perioperative blood conservation strategy reduced the incidence of red blood cell transfusion without increasing morbidity or mortality in patients undergoing aortic valve replacement, according to new study findings.
Current guidelines for blood conservation in cardiac surgery are based almost entirely on data from patients undergoing CABG, and there is little knowledge on the applicability to other areas of cardiac surgery, researchers wrote.
David W. Yaffee, MD, and colleagues at New York University Langone Medical Center analyzed 778 patients (mean age, 71.7 years) who underwent aortic valve replacement (AVR) at their institution. Patients were divided into two groups: those who underwent AVR between November 2007 and December 2009 before implementation of a blood conservation strategy (n=391) and those who underwent AVR between December 2009 and November 2011 after implementation of a blood conservation strategy (n=387).
The main components of the blood conservation strategy were emphasis on minimizing intraoperative hemodilution, tolerance of perioperative anemia at ≥8 g/dL instead of ≥10 g/dL, and education of all cardiac surgery team members. Also, “transfusions were performed according to physiologic need and not reflexively in response to laboratory values or for empiric or prophylactic reasons,” Yaffee and colleagues wrote.
Study outcomes included death, postoperative complications, and a composite of death, postoperative respiratory failure, renal failure requiring dialysis and sepsis.
The overall mortality rate was 3%. The rate was 1.7% for patients who underwent isolated first-time AVR. Deaths occurred only in patients who received at least two units of red blood cells.
The researchers found no differences between the groups in mortality (P=.5) or major complications (P=.4). However, after multivariable analysis, the blood conservation strategy was associated with a lower risk for major complications (OR=1.7; P=.046).
Patients in the pre-blood conservation strategy group had a 82.9% rate of red blood cell transfusion compared with 68% in the blood conservation strategy group (P<.01).
Lower risk for red blood cell transfusion was associated with isolated AVR (P<.01), a minimally invasive approach (P<.01) and inclusion in the blood conservation strategy group (P<.01). Higher risk for red blood cell transfusion was associated with older age (P<.01), prior cardiac surgery (P=.01), female sex (P<.01) and smaller body surface area (P<.01).
Need for a red blood cell transfusion of at least 2 units on the day of operation was associated with increased incidence of death (P=.01), prolonged intubation (P<.01), postoperative renal failure (P=.01) and increased incidence of any complication (P<.01).
“This change in institutional culture did not require any sophisticated or expensive pharmacologic or autologous-blood donation methods and was associated with a decreased risk for major complications as well as a substantial annual cost savings,” Yaffee and colleagues wrote.
Disclosure: Yaffee and colleagues report no relevant financial disclosures.