Factors determining achievement of early postoperative cardiac rehabilitation goal in patients with or without preoperative kidney dysfunction undergoing isolated cardiac surgery.

Background: The aim of this multicenter study was to evaluate the relationship between preoperative kidney function, postoperative acute kidney injury (AKI), and postoperative fluid balance (POFB) with the progress of early postoperative cardiac rehabilitation (CR) in patients undergoing isolated cardiac surgery.

Methods: Four hundred twenty three consecutive patients (137 females, 286 males, aged 66±13 years) who underwent various elective cardiac surgeries in the participating institutes were selected and divided into 5 groups depending on chronic kidney disease (CKD) stage. We evaluated the effects of CKD stage on the progress of early postoperative CR, and analyzed the factors determining the achievement of Japanese Circulation Society (JCS) early postoperative CR guidelines goal.

Results: Initiation of sitting (F=7.59, p<0.01) and standing (F=4.83, p<0.01), walking (F=4.40, p<0.01), and 100-m unassisted walk (F=13.09, p<0.01) were related with severity of preoperative CKD stage. The proportion of patients who could not achieve JCS early postoperative CR guideline goal was 15.0% in patients with CKD and 12.9% in patients without CKD. Multivariable analyses identified Risk, Injury, Failure, Loss, and End-stage Kidney (RIFLE) classification (of postoperative AKI) and blood urea nitrogen as factors determining achievement of early postoperative CR goal in patients with CKD; and POFB/preoperative body weight (PBW), RIFLE classification as determinants in patients without CKD. Using the receiver-operating characteristics curve analysis to predict achievement of the early postoperative CR goal, POFB/PBW 4.9% was identified as the cut-off value for achievement of the JCS early postoperative CR guideline goal.

Conclusion: Preoperative CKD stage correlated significantly with the progress of early postoperative CR after cardiac surgery. Independent determinants of achieving JCS early postoperative CR guideline goal were postoperative AKI in patients with or without CKD, and POFB/PBW only in patients without CKD.