A randomized trial of pulsatile perfusion using an intra-aortic balloon pump versus nonpulsatile perfusion on short-term changes in kidney function during cardiopulmonary bypass during myocardial reperfusion

Background: Nonpulsatile perfusion during cardiopulmonary bypass can induce renal damage. We evaluated whether pulsatile perfusion using an intra-aortic balloon pump preserves renal function in patients undergoing myocardial revascularization.

Study design: Randomized controlled trial, nonmasked parallel-group design.

Setting & participants: 100 patients undergoing preoperative perfusion using an intra-aortic balloon pump; 64 with baseline estimated glomerular filtration rate (eGFR) of 60 mL/min/1.73 m(2) or greater (>or=1 mL/s/1.73 m(2); stage 1 or 2) and 36 with eGFR of 30 to 59 mL/min/1.73 m(2) (0.5 to 0.98 mL/s/1.73 m(2); stage 3).

Intervention: Patients were randomly assigned to nonpulsatile perfusion during cardiopulmonary bypass (group A) or automatic intra-aortic balloon pump-induced pulsatile perfusion during cardiopulmonary bypass (group B).

Outcomes & measurements: Renal function, daily diuresis, complications, serum lactate levels, and other biochemical indices at 24 and 48 hours.

Results: GFR, adjusted for baseline eGFR, was 16 mL/min/1.73 m(2) [0.27 mL/s/1.73 m(2)] less in group A (58.1 mL/min/1.73 m(2); 95% confidence interval [CI], 56.1 to 60.1 mL/min/1.73 m(2) [0.97 mL/s/1.73 m(2); 95% CI, 0.94 to 1.0 mL/s/1.73 m(2)]) than in group B (74.0 mL/min/1.73 m(2); 95% CI, 72.0 to 76.1 mL/min/1.73 m(2) [1.23 mL/s/1.73 m(2); 95% CI, 1.20 to 1.27 mL/s/1.73 m(2)]; P < 0.001). Plasma lactate levels were +3.9 mg/dL (+0.43 mmol/L) higher in group A (19.5 mg/dL; 95% CI, 18.4 to 20.5 mg/dL [2.16 mmol/L; 95% CI, 2.04 to 2.28 mmol/L]) than in group B (16.7 mg/dL; 95% CI, 14.4 to 16.7 mg/dL [1.73 mmol/L; 95% CI, 1.60 to 1.85 mmol/L]; P < 0.001). No significant difference between the 2 groups was observed for 24-hour diuresis. Patients with eGFR stage 3 had a greater decrease in GFR and daily diuresis and greater increase in lactate levels than those with eGFR stages 1 to 2.

Limitations: Short-term change in kidney function as a surrogate outcome for "hard" clinical outcomes of mortality, morbidity, and length of hospitalization. Other limitations are short-term follow-up and absence of measurement of hemodynamic parameters or inflammatory mediators.

Conclusions: Use of automatic pulsatile intra-aortic balloon pumps during cardiopulmonary bypass is associated with better renal function during myocardial reperfusion. More studies are needed to verify the effects of pulsatile intra-aortic balloon pumps.