Acute kidney injury following surgical aortic valve replacement.

BACKGROUND: Acute kidney injury (AKI) is a significant complication of surgical aortic valve replacement (SAVR). This study sought to describe AKI following SAVR, its risk factors, predictors and effect on long-term survival. METHODS: We retrospectively reviewed 2169 patients who underwent isolated SAVR between 2000 and 2012. The main end-points were occurrence of AKI, postoperative complications, and short- and long-term survival rates following SAVR. Patients were divided into two groups: AKI+ (n = 181) and AKI- (n = 1945). RESULTS: AKI occurred in 8.5% of patients, of which 3.9% (n = 7) needed dialysis. Predictors of AKI after SAVR were body mass index (BMI) and intraoperative packed red blood cells (PRBC) transfusion. AKI+ patients had a more complicated postoperative course and higher cumulative mortality (25% vs. 17%, p = 0.012) with a median follow-up of 4.1 years. AKI was not found to be an independent predictor of mortality. CONCLUSIONS: Predictors of AKI after SAVR are increased BMI and intraoperative PRBC transfusion. AKI conferred an increase in hospital length of stay and cumulative mortality while the need for postoperative dialysis was associated with the most complicated hospital stays and the highest in-hospital and cumulative mortalities; therefore careful recognition of patients at risk of AKI is warranted for a better preoperative renal optimization. However, incidence of AKI was lower than what is reported after both on-CPB cardiac surgeries and transcatheter aortic valve replacement, moreover AKI was not found to be an independent predictor of mortality.

Combined Therapy of Ventricular Assist Device and Membrane Oxygenator for Profound Acute Cardiopulmonary Failure.

Short-term ventricular assist devices (ST-VADs) have been effective in treating the patients with refractory cardiogenic shock. Membrane oxygenators (MOs) can be added to the circuit for concomitant, profound refractory hypoxia. This study reports the outcomes of combined therapy in this portion of patients. This is a retrospective review of 166 patients who received an ST-biventricular assist device (BiVAD) or right ventricular assist device (RVAD) for cardiogenic shock between November 2007 and November 2014. An MO was added to the RVAD for profound hypoxia refractory to maximized ventilation. Patients were divided into two groups: 33 with (MO-VAD [MV]) and 133 without (VAD only [VO]) an MO. Survival to discharge and adverse events were compared between groups. More MV than VO patients were intubated (93.9% vs. 59.4%; p < 0.001) and on veno-arterial extracorporeal membrane oxygenator (VA-ECMO) (72.7% vs. 19.5%; p < 0.001) before implantation. Survival to discharge (51.5% MV vs. 52.6% VO; p = 0.515) and 1 year survival (54.4% MV vs. 48.6% VO; p = 0.955) were not significantly different. MV patients had more prolonged intubation (69.7% vs. 37.6%; p < 0.001), tracheostomies (39.4% vs. 16.5%; p = 0.008), and a higher risk for bleeding (p = 0.037). Patients suffering from cardiogenic shock with refractory hypoxia requiring combined ST-VAD and MO therapy appear to achieve similar mid-term survival despite increased risk for early complications.

Donors with a prior history of cardiac surgery are a viable source of lung allografts.

OBJECTIVES: End-stage lung disease continues to rise despite the lack of suitable lung donors, limiting the numbers of lung transplants performed each year. Expanded donor criteria, use of donation after cardiac death donors and the advent of ex vivo lung perfusion have resulted only in a slight increase in donor lung utilization. Organ donors with prior cardiac surgery (DPCS) present risks and technical challenges; however, they may be a potential source of suitable lung allografts with an experienced procurement surgeon. We present our experience having evaluated potential lung donors with a prior history of cardiac surgery, resulting in successful transplant outcomes. METHODS: This is a single-institution retrospective review of brain-dead organ donors that were evaluated for lung donation in the period 2012-15. Donor and recipient characteristics were collected. Post-lung transplant survival was recorded. RESULTS: From 2012 to 2015, 259 donors were evaluated, 12 with a prior history of cardiac surgery of which 4 had coronary artery bypass, 3 had aortic root replacement, 2 had aortic valve replacement, 1 pulmonary embolectomy, 1 two-time reoperative valve replacement and 1 paediatric congenital ventricular septal defect repair. DPCS, 6/12 (50% dry run) provided suitable allografts generating six single-lung transplants (three right and three left, 1 donor provided twin single-lung transplants) and one double-lung transplant. Interval between cardiac surgery and procurement for those rejected was median 5840 (IQR 2350-8640) days and interval for the donors that provided allografts was median 438 (IQR 336-1095) days (Mann-Whitney, P = 0.07). Recipient 1-year survival from DPCS is 100%. Recipient 1-year survival was 92% in allografts explanted from donors with no prior cardiac surgery (2012-13). CONCLUSION: To date, this is the largest single-centre experience using lung allografts from brain-dead DPCS. Our experience shows despite predicted technical difficulties, with good communication between thoracic and abdominal teams, successful transplant outcomes are possible, when surgeons with experience in reoperative cases are sent for lung procurements.

Donor lung assessment using selective pulmonary vein gases.

OBJECTIVES: Standard donor lung assessment relies on imaging, challenge gases and subjective interpretation of bronchoscopic findings, palpation and visual assessment. Central gases may not accurately represent true quality of the lungs. We report our experience using selective pulmonary vein gases to corroborate the subjective judgement. METHODS: Starting, January 2012, donor lungs have been assessed by intraoperative bronchoscopy, palpation and visual judgement of lung collapse upon temporary disconnection from ventilator, central gases from the aorta and selective pulmonary vein gases. Partial pressure of oxygen (pO2) <300 mmHg on FiO2 of 1.0 was considered low. The results of the chest X-ray and last pO2 in the intensive care unit were also collected. Post-transplant primary graft dysfunction and survival were monitored. RESULTS: To date, 259 consecutive brain-dead donors have been assessed and 157 transplants performed. Last pO2 in the intensive care unit was poorly correlated with intraoperative central pO2 (Spearman's rank correlation rs = 0.29). Right inferior pulmonary vein pO2 was associated (Mann-Whitney, P < 0.001) with findings at bronchoscopy [clean: median pO2 443 mmHg (25th-75th percentile range 349-512) and purulent: 264 mmHg (178-408)]; palpation [good: 463 mmHg (401-517) and poor: 264 mmHg (158-434)] and visual assessment of lung collapse [good lung collapse: 429 mmHg (320-501) and poor lung collapse: 205 mmHg (118-348)]. Left inferior pulmonary pO2 was associated (P < 0.001) with findings at bronchoscopy [clean: 419 mmHg (371-504) and purulent: 254 mmHg (206-367)]; palpation [good: 444 mmHg (400-517) and poor 282 mmHg (211-419)] and visual assessment of lung collapse [good: 420 mmHg (349-496) and poor: 246 mmHg (129-330)]. At 72 h, pulmonary graft dysfunction 2 was in 21/157 (13%) and pulmonary graft dysfunction 3 in 17/157 (11%). Ninety-day and 1-year mortalities were 6/157 (4%) and 13/157 (8%), respectively. CONCLUSIONS: Selective pulmonary vein gases provide corroborative objective support to the findings at bronchoscopy, palpation and visual assessment. Central gases do not always reflect true function of the lungs, having high false-positive rate towards the individual lower lobe gas exchange. Objective measures of donor lung function may optimize donor surgeon assessment, allowing for low pulmonary graft dysfunction rates and low 90-day and 1-year mortality.