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 m² or greater (≥1 mL/s/1.73 m²; stage 1 or 2) and 36 with eGFR of 30 to 59 mL/min/1.73 m² (0.5 to 0.98 mL/s/1.73 m²; 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 m² [0.27 mL/s/1.73 m²] less in group A (58.1 mL/min/1.73 m²; 95% confidence interval [CI], 56.1 to 60.1 mL/min/1.73 m² [0.97 mL/s/1.73 m²; 95% CI, 0.94 to 1.0 mL/s/1.73 m²]) than in group B (74.0 mL/min/1.73 m²; 95% CI, 72.0 to 76.1 mL/min/1.73 m² [1.23 mL/s/1.73 m²; 95% CI, 1.20 to 1.27 mL/s/1.73 m²]; 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.

Index Words: Renal function, cardiopulmonary bypass complications, pulsatile perfusion, renal dysfunction, renal hypoperfusion, hyperlactatemia