Multiorgan recovery in a cadaver body using mild hypothermic ECMO treatment in a murine model.

BACKGROUND: Transplant candidates on the waiting list are increasingly challenged by the lack of organs. Most of the organs can only be kept viable within very limited timeframes (e.g., mere 4-6 h for heart and lungs exposed to refrigeration temperatures ex vivo). Donation after circulatory death (DCD) using extracorporeal membrane oxygenation (ECMO) can significantly enlarge the donor pool, organ yield per donor, and shelf life. Nevertheless, clinical attempts to recover organs for transplantation after uncontrolled DCD are extremely complex and hardly reproducible. Therefore, as a preliminary strategy to fulfill this task, experimental protocols using feasible animal models are highly warranted. The primary aim of the study was to develop a model of ECMO-based cadaver organ recovery in mice. Our model mimics uncontrolled organ donation after an "out-of-hospital" sudden unexpected death with subsequent "in-hospital" cadaver management post-mortem. The secondary aim was to assess blood gas parameters, cardiac activity as well as overall organ state. The study protocol included post-mortem heparin-streptokinase administration 10 min after confirmed death induced by cervical dislocation under full anesthesia. After cannulation, veno-arterial ECMO (V-A ECMO) was started 1 h after death and continued for 2 h under mild hypothermic conditions followed by organ harvest. Pressure- and flow-controlled oxygenated blood-based reperfusion of a cadaver body was accompanied by blood gas analysis (BGA), electrocardiography, and histological evaluation of ischemia-reperfusion injury. For the first time, we designed and implemented, a not yet reported, miniaturized murine hemodialysis circuit for the treatment of severe hyperkalemia and metabolic acidosis post-mortem. RESULTS: BGA parameters confirmed profound ischemia typical for cadavers and incompatible with normal physiology, including extremely low blood pH, profound negative base excess, and enormously high levels of lactate. Two hours after ECMO implantation, blood pH values of a cadaver body restored from < 6.5 to 7.3 ± 0.05, pCO2 was lowered from > 130 to 41.7 ± 10.5 mmHg, sO2, base excess, and HCO3 were all elevated from below detection thresholds to 99.5 ± 0.6%, - 4 ± 6.2 and 22.0 ± 6.0 mmol/L, respectively (Student T test, p < 0.05). A substantial decrease in hyperlactatemia (from > 20 to 10.5 ± 1.7 mmol/L) and hyperkalemia (from > 9 to 6.9 ± 1.0 mmol/L) was observed when hemodialysis was implemented. On balance, the first signs of regained heart activity appeared on average 10 min after ECMO initiation without cardioplegia or any inotropic and vasopressor support. This was followed by restoration of myocardial contractility with a heart rate of up to 200 beats per minute (bpm) as detected by an electrocardiogram (ECG). Histological examinations revealed no evidence of heart injury 3 h post-mortem, whereas shock-specific morphological changes relevant to acute death and consequent cardiac/circulatory arrest were observed in the lungs, liver, and kidney of both control and ECMO-treated cadaver mice. CONCLUSIONS: Thus, our model represents a promising approach to facilitate studying perspectives of cadaveric multiorgan recovery for transplantation. Moreover, it opens new possibilities for cadaver organ treatment to extend and potentiate donation and, hence, contribute to solving the organ shortage dilemma.

The completeness of the left atrial appendage amputation during routine cardiac surgery.

BACKGROUND: Left atrial appendage (LAA) is the origin of most heart thrombi which can lead to stroke or other cerebrovascular event in patients with non-valvular atrial fibrillation (AF). This study aimed to prove safety and low complication rate of surgical LAA amputation using cut and sew technique with control of its effectiveness. METHODS: 303 patients who have undergone selective LAA amputation were enrolled in the study in a period from 10/17 to 08/20. The LAA amputation was performed concomitant to routine cardiac surgery on cardiopulmonary bypass with cardiac arrest with or without previous history of AF. The operative and clinical data were evaluated. Extent of LAA amputation was examined intraoperatively by transoesophageal echocardiography (TEE). Six months in follow up, the patients were controlled regarding clinical status and episodes of strokes. RESULTS: Average age of study population was 69.9 ± 19.2 and 81.9% of patients were male. In only three patients was residual stump after LAA amputation larger than 1 cm with average stump size 0.28 ± 0.34 cm. 3 patients (1%) developed postoperative bleeding. Postoperatively 77 (25.4%) patients developed postoperative AF (POAF), of which 29 (9.6%) still had AF at discharge. On 6 months follow up only 5 patients had NYHA class III and 1 NYHA class IV. Seven patients reported with leg oedema and no patient experienced any cerebrovascular event in early postoperative follow up. CONCLUSION: LAA amputation can be performed safely and completely leaving minimal to no LAA residual stump.

Subacute Aortic Rupture Due to Mechanical Chest Compression with Indwelling Impella.

Mechanical cardiopulmonary resuscitation (CPR) devices like Lund University Cardiopulmonary Assist System (LUCAS) cause more skeletal and visceral injuries than standard CPR. A 62-year-old woman with ST-elevation myocardial infarction was resuscitated with LUCAS and Impella CP for refractory cardiogenic shock during percutaneous coronary intervention. She suffered delayed ascending aortic rupture necessitating supracommissural ascending aortic replacement plus triple bypass grafting. Prolonged mechanical CPR with concomitant Impella may lead to aortic rupture. The combined use of LUCAS and Impella may have disastrous consequences.

Benefits of Intra-Aortic Balloon Pump Support in Patients with Postcardiotomy Shock Requiring Venoarterial Extracorporeal Membrane Oxygenation.

BACKGROUND: The benefit of the combined use of an intra-aortic balloon pump (IABP) and venoarterial extracorporeal membrane oxygenation (VA-ECMO) for postcardiotomy shock remains unclear. We aimed to analyse the potential benefits and safety of combining these two devices. METHODS: We enrolled 200 patients treated with either VA-ECMO only or in combination with IABP (ECMO-I group) between January 2012 and January 2021. To adjust the patients' backgrounds, we used propensity score matching for additional analyses, resulting in 57 pairs. The primary endpoint was 30-day survival. Secondary endpoints included successful weaning and complication rates. We also analysed hemodynamic parameters in both groups. RESULTS: After propensity score matching, 30-day survival was better in the ECMO-I group (log-rank p = 0.004). The ECMO-I and ECMO-only groups differed regarding the secondary endpoints, including successful weaning (50.9% and 26.3%, respectively; p = 0.012) and the need for continuous renal replacement therapy (28.1% and 50.9%, p = 0.021). Complication rates were not statistically different between the two groups. CONCLUSION: Compared to VA-ECMO alone, the combined use of VA-ECMO and IABP is beneficial regarding 30-day survival in selected patients with postcardiotomy shock; successful ECMO weaning and freedom from renal replacement therapy is more common in patients supported with VA-ECMO plus IABP.

Left Ventricular Assist Device Implantation in a Patient with Ventricular Pseudoaneurysm.

Background Left ventricular assist device (LVAD) implantation after contained LV rupture (pseudoaneurysm) represents a difficult surgical problem. Case Description We describe the surgical approach for such a patient. The sewing ring was implanted utilizing a Dacron patch for reconstruction of the free wall, fibrotic LV wall remnants, and a Teflon strip giving additional support for cannula position and hemostasis. The patient had an uneventful recovery and is well 19 months after the procedure. Conclusion LV pseudoaneurysm is not a contraindication for permanent LVAD implantation.

Decellularized Pulmonary Xenograft Matrix PplusN versus Cryopreserved Homograft for RVOT Reconstruction during Ross Procedure in Adults.

BACKGROUND: Decellularized pulmonary homografts are being increasingly adopted for right ventricular outflow tract reconstruction in adult patients undergoing the Ross procedure. Few reports presented Matrix PplusN xenograft (Matrix) in a negative light. The objective of this study was to compare our midterm outcomes of Matrix xenograft versus standard cryopreserved pulmonary homograft (CPHG). METHODS: Eighteen patients received Matrix xenograft between January 2012 and June 2016, whereas 66 patients received CPHG. Using nonparametric statistical tests and survival analysis, we compared midterm echocardiographic and clinical outcomes between the groups. RESULTS: Except for significant age difference (the Matrix group was significantly older with 57 ± 8 years than the CPHG group, 48 ± 9 years, p = 0.02), the groups were similar in all other baseline characteristics. There were no significant differences in cardiopulmonary bypass times (208.3 ± 32.1 vs. 202.8 ± 34.8) or in cross-clamp times (174 ± 33.9 vs. 184.4 ± 31.1) for Matrix and CPHG, respectively. The Matrix group had significantly inferior freedom from reintervention than the CPHG group with 77.8 versus 98.5% (p = 0.02). Freedom from pulmonary valve regurgitation ≥ 2 was not significantly different between the groups with 82.4 versus 90.5% for Matrix versus CPHG, respectively. After median follow-up of 4.9 years, Matrix xenograft developed significantly higher peak pressure gradients compared with CPHG (20.4 ± 15.5 vs. 12.2 ± 9.0 mm Hg; p = 0.04). CONCLUSION: After 5 years of clinical and echocardiographic follow-up, the decellularized Matrix xenograft had inferior freedom from reintervention compared with the standard CPHG. Closer follow-up is necessary to avoid progression of valve failure into right ventricular deterioration.

Fibrin Sealant Patch for the Management of Intractable Bleeding From an LVAD Apex Cannula.

BACKGROUND: Intractable bleeding from the apical cannulation site of a left ventricular assist device (LVAD) is a dreaded complication. CASE REPORT: A 52-year-old male suffering from dilative cardiomyopathy (DCM) with fixed pulmonary hypertension underwent reoperative LVAD implantation after previous mitral valve surgery. The patient underwent three rethoracotomies for bleeding from the apex cannulation site without achieving hemostasis. Conventional techniques and application of fibrin sealants and polymeric sealing devices did not fix the problem. The bleeding stopped after application of the EVARREST® Fibrin Sealant Patch (FSP), and he needed no further transfusions. CONCLUSION: This patch might become a useful tool for intractable bleeding problems in LVAD surgery.

Central Versus Peripheral Arterial Cannulation for Veno-Arterial Extracorporeal Membrane Oxygenation in Post-Cardiotomy Patients.

Different arterial cannulation strategies are feasible for veno-arterial extracorporeal membrane oxygenation (VA-ECMO) in postcardiotomy shock. We aimed to analyze potential benefits and safety of different arterial cannulation strategies. We identified 158 patients with postcardiotomy cardiogenic shock requiring VA-ECMO between 01/10 and 01/19. Eighty-eight patients were cannulated via axillary or femoral artery (group P), and 70 centrally via the ascending aorta directly or through an 8 mm vascular graft anastomosed to the ascending aorta (group C). Demographics and operative parameters were similar. Change of cannulation site for Harlequin's syndrome or hyperperfusion of an extremity occurred in 13 patients in group P but never in group C (p = 0.001). Surgical revision of cannulation site was also encountered more often in group P than C. The need for left ventricular (LV) unloading was similar between groups, whereas surgical venting was more often implemented in group C (11.4% vs. 2.3, p = 0.023). Stroke rates, renal failure, and peripheral ischemia were similar. Weaning rate from ECMO (52.9% vs. 52.3%, p = NS) was similar. The 30 day mortality was higher in group P (60% vs. 76.1%, p = 0.029). Central cannulation for VA-ECMO provides antegrade flow without Harlequin's syndrome, changes of arterial cannula site, and better 30 day survival. Complication rates regarding need for reexploration and transfusion requirements were similar.

First clinical experience with the novel cold storage SherpaPak™ system for donor heart transportation.

BACKGROUND: The current gold standard for donor heart preservation is a three-bag-technique and storage in a cooler filled with slush ice. This technique can cause freezing injury with protein denaturation. We report our early experience with a single-use disposable device (SherpaPak™, Paragonix Technologies, MA, USA) specifically designed for sterile permanent temperature-controlled transportation of donor hearts. METHODS: In this case control study with 2:1 matching we identified 21 patients after heart transplantation depending on type of organ transport (standard three-bag-technique vs. SherpaPak™). The outcome after donor heart storage in the SherpaPak™ was compared with donor heart transportation with the standard technique. RESULTS: Since July 2018 seven patients (5 males; mean age 50.3±13.2years) underwent heart transplantation with the SherpaPak™ system. Cold ischemic time was longer in the SherpaPak™ group (207.7±23.3 vs. 181.6±21.9, P=0.027). SherpaPak™ kept the organ temperature at 5.1±0.8 °C, with an average outside temperature of 21.4±3.6 °C. Among all 21 transplanted patients four developed fatal early graft failure (28.6% vs. 21.4%, P=0.432). Over the first hours we noticed no difference in hemodynamic parameters, CK-MB levels or vasoactive-inotropic score. During first follow-up we noticed slightly better right heart function in the SherpaPak™ group (TAPSE 17.83±2.71 vs. 14.52±2.61 mm, P=0.020). We identified no positive blood cultures in the SherpaPak™ group within the first 30 days after heart transplantation. CONCLUSIONS: The SherpaPak™ provides a constant temperature during transportation with permanent monitoring, never dropping below 4 °C. Organs transported with this novel device showed a normal perioperative function.

Impact of diabetes mellitus on the contractile properties of the left and right atrial myofilaments.

OBJECTIVES: The incidence of diabetes mellitus in patients with ischaemic cardiomyopathy is increasing. To evaluate the impact of diabetes mellitus on contractility, we examined the calcium-induced force in left and right atrial myofilaments of patients with and without diabetes. METHODS: We included 149 patients (106 without diabetes, 43 with diabetes), scheduled for elective coronary artery bypass grafting from August 2016 to June 2017. The left and right atria were excised and prepared for skinned fibre measurements (pCa-force curve). The unit for the force measurements is Millinewton (mN). Comprehensive demographic data as well as echocardiographic findings of the patients were collected. RESULTS: We observed a significant decrease of left atrial force values in patients with diabetes, averaged over all calcium concentrations (patients with diabetes 0.50 ± 0.19 mN vs 0.68 ± 0.23 mN in patients without diabetes, P = 0.002) as well as in right atrial fibres (patients with diabetes 0.35 ± 0.17 mN vs 0.47 ± 0.21 mN in patients without diabetes, P = 0.005). There was a significant influence of repeated measurements (of the calcium concentrations) on force in left atrial myofilaments (P < 0.001). There was also a significant impact of diabetes on the force values of the different calcium concentrations in left atrial myofilaments (P 0.002). In right atrial myofilaments we also found a significant influence of repeated measurements (of the calcium concentrations) on force (P < 0.001). Additionally the impact of diabetes on the force values was significant (P = 0.005). CONCLUSIONS: We demonstrated that diabetes mellitus has a significantly negative impact on calcium-induced force development in left and right atrial myofilaments.

Venovenous extracorporeal membrane oxygenation for the management of contralateral iatrogenic bronchus perforation during lower bilobectomy.

Tracheobronchial rupture by a double-lumen endobronchial tube is a rare but life-threatening complication. We report a case of bronchial rupture during contralateral bilobectomy. Venovenous extracorporeal membrane oxygenation support was instituted via the right femoral vein and the internal jugular vein with the patient in the left lateral decubitus position. Sleeve resection of the ruptured bronchus was performed. The patient was successfully discharged home. Rapid institution of venovenous extracorporeal membrane oxygenation is helpful to manage this intraoperative complication.

Secondary sclerosing cholangitis in cardiac surgical patients: A complication with a dismal prognosis.

OBJECTIVES: Secondary sclerosing cholangitis in critically ill patients is a rapidly progressing disease leading to biliary fibrosis and cirrhosis. We describe the course of sclerosing cholangitis in critically ill patients after cardiac surgery and compare this with matched patients. METHODS: A retrospective search for "secondary sclerosing cholangitis" and "liver and/or hepatic failure" in all adult patients (aged 18-93 years) who underwent cardiac surgery from April 2007 to March 2016 identified 192 of 8625 patients. Of those, 12 were diagnosed with sclerosing cholangitis in critically ill patients (incidence, 0.14%). A 3:1 matching was performed. Laboratory values, pharmacologic requirements, ventilation times, mechanical circulatory support, and endoscopic retrograde cholangiopancreatography studies were extracted from the hospital database. RESULTS: A total of 9 men and 3 women were affected (age 71 years; range, 59.8-75.5 years). Critically ill patients with sclerosing cholangitis required vasoconstrictors and inotropes longer than control patients (norepinephrine 356.5 hours [264.5-621] vs 68 hours [15-132.5], P = .003; enoximone 177 hours [124.3-249.5] vs 48.5 hours [12-81 hours], P < .001, respectively). Critically ill patients with sclerosing cholangitis had longer intubation time (628.5 hours [377.3-883] vs 25 hours [9.8-117.5]; P < .001) and more surgical revisions (3 [2.5-6] vs 1 [0-2], P = .003) than the matching group. Bilirubin (23.3 mg/dL [14.4-32.9] vs 1 mg/dL [0.6-2.7]; P < .001), gamma-glutamyltransferase (1082.3 U/L [259.5-2265.7] vs 53.8 U/L [35.1-146]; P < .001), and alkaline phosphatase (751.5 U/L [372-1722.3] vs 80.5 U/L [53.3-122]; P < .001) were higher in critically ill patients with sclerosing cholangitis. One critically ill patient with sclerosing cholangitis underwent successful liver transplantation. A total of 11 patients sclerosing cholangitis died (92%) versus 12 patients (33%, P < .001) in the control group. CONCLUSIONS: Sclerosing cholangitis in critically ill patients is a fatal complication in patients undergoing cardiac surgery who have a complicated postoperative course with prolonged vasoconstrictor, inotropic, and respiratory therapy, or who require frequent surgical revisions. Liver transplantation remains the only curative option but is often precluded by the age and critical state of patients undergoing cardiac surgery.