Blood conservation strategy lowers transfusion risk during AVR

Using a blood conservation strategy (BCS) in patients undergoing aortic valve replacement (AVR) reduced the need for blood transfusions without increasing mortality or morbidity, according to a study published in the January issue of Annals of Thoracic Surgery.

David W. Yaffee, MD, and colleagues at New York University Langone Medical Center in New York City reviewed clinical and transfusion data for 778 patients who underwent AVR at their facility between 2007 and 2011. A BCS protocol was implemented gradually over that time period, so to simplify, they broke the study period into two different time frames—Nov. 1, 2007 to Dec. 3, 2009 (pre-BCS) and Dec. 4, 2009 to Nov. 30, 2011 (post-BCS). They then compared the two groups for incidence of red blood cell (RBC) transfusion and other outcomes, including death and postoperative complications.

The BCS focused on minimizing intraoperative hemodilution, tolerating a perioperative hemoglobin level of 8 g/dL or higher and educating all members of the surgical team.

Fewer patients in the post-BCS group needed RBC transfusions than the pre-BCS group (82.9 percent vs. 68 percent). More than 60 percent of the patients who did not receive RBC transfusions on the day of surgery did not receive RBC transfusions after surgery.

There was an association between lower risk of RBC transfusion and isolated AVR and a minimally invasive approach. Older age, previous cardiac surgeries, female sex and less body surface area were associated with a higher risk of RBC transfusion. RBC transfusion with two or more units on the day of surgery was associated with more deaths, longer intubation time and more complications.

Overall mortality was 3 percent, and 1.7 percent of patients who underwent isolated AVR for the first time died.  

The authors noted the BCS protocol has been previously studied in patients who had CABG surgery, but never in AVR patients. However, they found that BCS strategy did not require any special blood donation methods and also saved a considerable amount of money.

“Guidelines for BCS in routine cardiac operations should be extended to AVR patients,” they wrote.