Impact of a clinical pathway on acute kidney injury in patients undergoing heart transplant.

BACKGROUND: To evaluate the impact of a clinical pathway on the incidence and severity of acute kidney injury in patients undergoing heart transplant. METHODS: This was a 2.5-year retrospective evaluation using 3 years of historical controls within a cardiac intensive care unit in an academic children's hospital. Patients undergoing heart transplant between May 27, 2014, and April 5, 2017 (pre-pathway) and May 1, 2017, and November 30, 2019 (pathway) were included. The clinical pathway focused on supporting renal perfusion through hemodynamic management, avoiding or delaying nephrotoxic medications, and providing pharmacoprophylaxis against AKI. RESULTS: There were 57 consecutive patients included. There was an unadjusted 20% reduction in incidence of any acute kidney injury (p = .05) and a 17% reduction in Stage 2/3 acute kidney injury (p = .09). In multivariable adjusted analysis, avoidance of Stage 2/3 acute kidney injury was independently associated with the clinical pathway era (AOR -1.3 [95% CI -2.5 to -0.2]; p = .03), achieving a central venous pressure of or less than 12 mmHg (AOR -1.3 [95% CI -2.4 to -0.2]; p = .03) and mean arterial pressure above 60 mmHg (AOR -1.6 [95% CI -3.1 to -0.01]; p = .05) in the first 48 h post-transplant, and older age at transplant (AOR - 0.2 [95% CI -0.2 to -0.06]; p = .002). CONCLUSIONS: This report describes a renal protection clinical pathway associated with a reduction in perioperative acute kidney injury in patients undergoing heart transplant and highlights the importance of normalizing perioperative central venous pressure and mean arterial blood pressure to support optimal renal perfusion.

Perfusion Methods and Modifications to the Cardiopulmonary Bypass Circuit for Midline Unifocalization Procedures.

Pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries (PA/VSD/MAPCAs) is a rare form of congenital heart disease. The midline unifocalization procedure has been developed for the treatment of PA/VSD/MAPCAs. These are complex and very lengthy procedures that require an entirely different method of perfusion. The purpose of this study was to review our perfusion modifications to support these unifocalization procedures. Sixty-four unifocalization procedures have been performed at our institution during the past 3 years. The median age was 4.1 months (range 1 month-3.5 years) and the median weight at surgery was 4.5 kg (range 3.5-19 kg). The median duration of cardiopulmonary bypass was 352 minutes (range 128-629 minutes), and the median duration of cross-clamp was 24 minutes (range 14-72 minutes). The conduct of surgery included cooling to a rectal perfusion temperature of 25° and a flow rate of 100 mL/kg/min. A pH-stat strategy and del Nido cardioplegia were used. Modifications to the cardiopulmonary bypass circuit include upsizing the oxygenator, reservoir, cannulae, vent catheter, and tubing. All circuits were modified to include the capability of performing an intraoperative flow study. This study is used to determine whether the VSD can be closed during surgery. A collateral flow study circuit is also set up for first-time operations to measure the residual collateral flow after all of the MAPCAs have been harvested. Patients who require midline unifocalization will invariably require very lengthy periods of support on cardiopulmonary bypass. We have adapted our perfusion circuitry to prepare for the demands on the bypass circuit to meet the requirements of this patient population. Our institution has developed a systematic approach for the conduct of perfusion to best serve our patients presenting with PA/VSD/MAPCAs.

Transfusion Outcomes in Patients Undergoing Unifocalization and Repair of Tetralogy of Fallot With Major Aortopulmonary Collaterals.

BACKGROUND: Surgical repair of tetralogy of Fallot and major aortopulmonary collaterals (TOF/MAPCAs) involves unifocalization of MAPCAs and reconstruction of the pulmonary arterial circulation. Surgical and cardiopulmonary bypass (CPB) times are long and suture lines are extensive. Maintaining patency of the newly anastomosed vessels while achieving hemostasis is important, and assessment of transfusion practices is critical to successful outcomes. METHODS: Clinical, surgical, and transfusion data in patients with TOF/MAPCAs repaired at our institution (2013-2018) were reviewed. Types and volumes of blood products used in the perioperative period, in addition to the use of antifibrinolytics and/or procoagulants (factor VIII inhibitor bypassing activity [FEIBA]; anti-inhibitor coagulant complex), were assessed. Outcome measures included days on mechanical ventilation (DOMV), postoperative intensive care unit and hospital length of stay (LoS), and incidence of thrombosis. RESULTS: Perioperative transfusion data from 279 patients were analyzed. Surgical (879 ± 175 minutes vs 684 ± 257 minutes) and CPB times (376 ± 124 minutes vs 234 ± 122 minutes) were longer in patients who received FEIBA than those who did not. Although the indexed volume of packed red blood cells (128.4 ± 82.2 mL/kg) and fresh frozen plasma (64.2 ± 41.1 mL/kg) was similar in patients who did and did not receive FEIBA, the amounts of cryoprecipitate (5.5 ± 5.2 mL/kg vs 5.8 ± 4.8 mL/kg) and platelets (19.5 ± 20.7 mL/kg vs 20.8 ± 13 mL/kg) transfused were more in those who did receive FEIBA. CONCLUSION: Perioperative transfusion is an important component in the overall surgical and anesthetic management of patients with TOF/MAPCAs. The intraoperative use of FEIBA was not associated with a decrease in the amount of blood products transfused, DOMV, or LoS or with an increase in thrombotic complications.

Measurement of Residual Collateral Flow in Pulmonary Atresia With Major Aortopulmonary Collaterals.

BACKGROUND: Pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries (MAPCAs) is a rare form of congenital heart disease characterized by the entirety of pulmonary blood flow originating from systemic vessels. This study measured the residual collateral flow after harvesting of the MAPCAs for surgical repair. METHODS: The study enrolled 32 patients with pulmonary atresia with ventricular septal defect and MAPCAs who were undergoing their first surgical procedure. The median age was 6.8 months, and median weight was 5.7 kg. The patients had a mean of 4.2 ± 0.7 MAPCAs. The cardiopulmonary bypass circuit was modified to contain a diversion loop in the left ventricular vent system to accurately measure residual collateral flow. During the period of aortic cross-clamp (for ventricular septal defect repair), the diversion loop was opened for 1-minute intervals, and the residual collateral flow collected. The systemic perfusion temperature was 25° and flow rate was 100 mL · kg-1 · min-1. RESULTS: The mean residual collateral flow was 5.5 mL · kg-1 · min-1 (range, 0.8 to 15.2 mL · kg-1 · min-1). The corresponding calculated pulmonary blood flow-to-systemic blood flow ratio values ranged from 1.01 to 1.36. There was a significant correlation between residual collateral flow and preoperative saturation (p < 0.05). CONCLUSIONS: The data demonstrate a wide range of residual collateral flow values after harvesting of the MAPCAs. The amount of residual collateral flow was correlated with preoperative saturation. These results suggest that some patients at the higher end of this spectrum may require adjustments in pump flow to assure adequate systemic perfusion.