Perfusion Strategies Research Articles

P48 RETROSPECTIVE POSTOPERATIVE NEAR INFRARED SPECTROSCOPY MONITORING ANALYSIS TO DETECT POTENTIAL CRITERIA TO IMPROVE POSTOPERATIVE PREDICTION OF UNFAVOURABLE OUTCOME FOLLOWING AORTIC SURGERY

Abstract Objective Near Infrared Spectroscopy (NIRS) monitoring has become a frequent practice during aortic surgery. The real impact of NIRS in predicting postoperative outcomes, however is still debated, as many cases of “false negative” with severe cerebral damage despite apparently normal NIRS monitoring during surgical procedure. We applied extended retrospective postoperative NIRS monitoring analysis in order to investigate potential criteria to enhance postoperative unfavorable outcome prediction. Materials and Methods Data of NIRS monitoring of 41 patients undergoing aortic surgery (19 acute dissection) were retrospectively analyzed. Partial circulatory arrest with selective bilateral (21 pts) or unilateral (20 pts) cerebral perfusion (CP) was used in all patients. Double channel (R and L) NIRS value was continuously recorded (every 30 sec) from anaesthetic induction to patient’s transfer to ICU. Postoperatively all data were downloaded in excel format and retrospectively analyzed. Baseline, maximum, and minimum value with percentage drop and R/L channel gap were all analyzed considering 5 different phases of surgery: before extracorporeal circulation (EC); in EC before circulatory arrest and selective cerebral perfusion (CA–SCP); in EC following CA–SCP, following EC. Overall time <25% (in each channel) or with a > 20% gap were also evaluated. Results Overall 661±125 values were recorded for each patient. Baseline value on the Left (61±7) was significantly lower then Right (66±12). Maximum drop did not differed in two channels (Fig 1a) but varied according surgical phases (Fig 1). R/L asymmetry also varied according surgical phases with a peak value during rewarming and not during CA–SCP despite unilateral SCP and complexity of procedure (Figure 2 and 3). Conclusion Extended postoperative analysis of NIRS recorded value shows different trend and behavior according surgical phase and cerebral perfusion strategy. Accurate extended NIRS analysis is therefore mandatory in order to improve knowledge of physiological cerebral perfusion during SCP and early identification of patients at high risk of postoperative cerebral complications.

Engineering Vascularized Islet Macroencapsulation Devices: An in vitro Platform to Study Oxygen Transport in Perfused Immobilized Pancreatic Beta Cell Cultures.

Islet encapsulation devices serve to deliver pancreatic beta cells to type 1 diabetic patients without the need for chronic immunosuppression. However, clinical translation is hampered by mass transport limitations causing graft hypoxia. This is exacerbated in devices relying only on passive diffusion for oxygenation. Here, we describe the application of a cylindrical in vitro perfusion system to study oxygen effects on islet-like clusters immobilized in alginate hydrogel. Mouse insulinoma 6 islet-like clusters were generated using microwell plates and characterized with respect to size distribution, viability, and oxygen consumption rate to determine an appropriate seeding density for perfusion studies. Immobilized clusters were perfused through a central channel at different oxygen tensions. Analysis of histological staining indicated the distribution of viable clusters was severely limited to near the perfusion channel at low oxygen tensions, while the distribution was broadest at normoxia. The results agreed with a 3D computational model designed to simulate the oxygen distribution within the perfusion device. Further simulations were generated to predict device performance with human islets under in vitro and in vivo conditions. The combination of experimental and computational findings suggest that a multichannel perfusion strategy could support in vivo viability and function of a therapeutic islet dose.

Beneficial Effects of Adjusted Perfusion and Defibrillation Strategies on Rhythm Control within Controlled Automated Reperfusion of the Whole Body (CARL) for Refractory Out-of-Hospital Cardiac Arrest.

Survival and neurological outcomes after out-of-hospital cardiac arrest (OHCA) remain low. The further development of prehospital extracorporeal resuscitation (ECPR) towards Controlled Automated Reperfusion of the Whole Body (CARL) has the potential to improve survival and outcome in these patients. In CARL therapy, pulsatile, high blood-flow reperfusion is performed combined with several modified reperfusion parameters and adjusted defibrillation strategies. We aimed to investigate whether pulsatile, high-flow reperfusion is feasible in refractory OHCA and whether the CARL approach improves heart-rhythm control during ECPR. In a reality-based porcine model of refractory OHCA, 20 pigs underwent prehospital CARL or conventional ECPR. Significantly higher pulsatile blood-flow proved to be feasible, and critical hypotension was consistently prevented via CARL. In the CARL group, spontaneous rhythm conversions were observed using a modified priming solution. Applying potassium-induced secondary cardioplegia proved to be a safe and effective method for sustained rhythm conversion. Moreover, significantly fewer defibrillation attempts were needed, and cardiac arrhythmias were reduced during reperfusion via CARL. Prehospital CARL therapy thus not only proved to be feasible after prolonged OHCA, but it turned out to be superior to conventional ECPR regarding rhythm control.

Matched comparison of 3 cerebral perfusion strategies in open zone-0 anastomosis for acute type A aortic dissection.

The present study aims to investigate outcomes after the surgical treatment of acute type A aortic dissection in regard to three available selective cerebral perfusion strategies. From 2000 to 2019, patients were selected based on the employment of either retrograde cerebral perfusion (RCP), unilateral antegrade cerebral perfusion (uACP) or bilateral antegrade cerebral perfusion (bACP) during open zone-0 anastomosis. Propensity score TriMatch analysis considering several preoperative and intraoperative variables was used to identify well-balanced triplets. The primary end point of the study was a new cerebral operation-related neurologic deficit. Operative times (operation time, cardiopulmonary bypass time, reperfusion time) were significantly longer in the RCP group, in which deeper hypothermia was applied (27.5 [24-28], 28 [26-28] and 16 [16-17]°C for uACP, bACP and RCP, respectively, P-value <0.001). The RCP group showed higher red blood cell concentrates and fresh frozen plasma transfusion rates. No significant difference of new cerebral operation-related neurologic deficit was observed between the 3 groups (12.9% vs 12.9% vs 11.3% for RCP, uACP and bACP, P-value = 0.86). In addition, 30-day mortality showed similar distribution independently of the cerebral perfusion strategy adopted (17.7% vs 14.5% vs 17.7% for RCP, uACP and bACP, P-value = 0.86). However, based on a small sample size, the comparison showed no relevant differences in terms of neurologic outcome and 30-day mortality, confirming RCP, uACP and bACP as safe and reproducible selective cerebral perfusion strategies in surgery for acute type A aortic dissection.

Impact of Whole-Body Perfusion in Postoperative Outcomes After Aortic Arch Reconstruction Surgery in Neonates and Infants.

The aim of this study was to determine whether whole-body perfusion (WBP) consisting of a combined antegrade cerebral perfusion (ACP) and lower body perfusion (LBP) improves the outcome after aortic arch reconstruction surgery in neonates compared with ACP. Sixty-five consecutive patients under one year of age who underwent aortic arch reconstruction as the main procedure or as part of a more complex surgery from 2014-2020 in our center were included. The patients were separated into two groups, according to the perfusion strategy, either ACP (34 patients) as the control group or WBP (31 patients) as the intervention group. LBP was achieved through an arterial sheath in the femoral artery. Outcome parameters were postoperative renal, gastrointestinal, and neurological complications and 30-day mortality. The patients in the WBP group showed lower intraoperative lactate levels and close to normal early postoperative renal and hepatic enzymes and LDH at PICU admission compared with the patients in the ACP group. The number of patients suffering from postoperative neurological complications and multiorgan failure was lower in the WBP group. In our experience, the combined use of ACP and LBP through the femoral artery showed an improvement, regarding postoperative neurologic complications in neonates and infants undergoing aortic arch surgery.

Donation after Circulatory Death Liver Transplantation in Paediatric Recipients

Waiting list mortality together, with limited availability of organs, are one of the major challenges in liver transplantation (LT). Especially in the paediatric population, another limiting factor is the scarcity of transplantable liver grafts due to additional concerns regarding graft size matching. In adults, donation after circulatory death (DCD) liver grafts have been used to expand the donor pool with satisfactory results. Although several studies suggest that DCD livers could also be used in paediatric recipients with good outcomes, their utilisation in children is still limited to a small number of reports. Novel organ perfusion strategies could be used to improve organ quality and help to increase the number of DCD grafts utilised for children. With the current manuscript, we present the available literature of LT using DCD grafts in paediatric recipients, discussing current challenges with the use of these livers in children and how machine perfusion technologies could be of impact in the future.

Mesenchymal Stromal/Stem Cells and Their Products as a Therapeutic Tool to Advance Lung Transplantation.

Lung transplantation (LTx) has become the gold standard treatment for end-stage respiratory failure. Recently, extended lung donor criteria have been applied to decrease the mortality rate of patients on the waiting list. Moreover, ex vivo lung perfusion (EVLP) has been used to improve the number/quality of previously unacceptable lungs. Despite the above-mentioned progress, the morbidity/mortality of LTx remains high compared to other solid organ transplants. Lungs are particularly susceptible to ischemia-reperfusion injury, which can lead to graft dysfunction. Therefore, the success of LTx is related to the quality/function of the graft, and EVLP represents an opportunity to protect/regenerate the lungs before transplantation. Increasing evidence supports the use of mesenchymal stromal/stem cells (MSCs) as a therapeutic strategy to improve EVLP. The therapeutic properties of MSC are partially mediated by secreted factors. Hence, the strategy of lung perfusion with MSCs and/or their products pave the way for a new innovative approach that further increases the potential for the use of EVLP. This article provides an overview of experimental, preclinical and clinical studies supporting the application of MSCs to improve EVLP, the ultimate goal being efficient organ reconditioning in order to expand the donor lung pool and to improve transplant outcomes.

The efficient development of a novel recombinant adenovirus zoster vaccine perfusion production process

The adenovirus vector vaccines induce humoral and cellular immune responses and have been used to develop vaccines for effective prevention of life-threating viruses, such as Ebola and Coronaviruses. High demand of vaccines worldwide requires optimization of the production process. Perfusion process increases cell concentration and volumetric productivity, so that it becomes the commonly used strategy in vaccine production In this study, we optimized and developed a perfusion process for the adenovirus-based zoster vaccine production efficiently. We first tested different perfusion strategies in shake flasks, showing semi-continuous strategies for optimal HEK 293 cell growth. We then evaluated three empirical key process parameters (cell concentration at the time of infection (VCC), multiplicity of infection (MOI), virus production pH) by the design of experiment (DoE) method, from which the robust setpoint (VCC 1.04 × 107 cells/mL, MOI 9, and virus production pH 7.17) was confirmed in both shake flask and 2 L benchtop bioreactor. In the bioreactor, we compared the performances of two perfusion systems, the commercially-available XCell ATF® system and a novel peristaltic pump-driven alternating tangential flow perfusion system (PATFP system) that we developed. During cell cultivation stage, both perfusion systems have comparable performances regarding viable cell concentration and cell viability. At 2 dpi, the PATFP system resulted in an adenovirus titer of 2.1 × 1010 IFU/mL and cell-specific virus yield of 2,062 IFU/cell, reaching 75% and 77% of values for XCell ATF® system. This study demonstrates the perfusion process to be superior strategy for adenovirus-based vaccine production compared to the batch-mode strategy (1,467 IFU/cell). Furthermore, our PATFP system shows potential to be comparable to the XCell ATF® system, and it would become an alternative perfusion strategy for the vaccine production.

Total Arch Replacement With Frozen Elephant Trunk Using a NEW "Brain-Heart-First" Strategy for Acute DeBakey Type I Aortic Dissection Can Be Performed Under Mild Hypothermia (≥30°C) With Satisfactory Outcomes.

BackgroundTotal arch replacement (TAR) with Frozen elephant trunk (FET) treatment of acute DeBakey type I aortic dissection (ADIAD) is complicated, carries a high complication/mortality risk and remains controversial on the optimal hypothermic level, cerebral perfusion and visceral organ protection strategy. We developed a new strategy named “Brain-Heart-first” in which the surgical procedures and the management of cardiac perfusion/cerebral protection during Cardiopulmonary bypass (CPB) were redesigned, and TAR with FET technique can be performed under mild hypothermia with satisfactory outcomes.ObjectiveOur aims were to describe a new surgical strategy under mild hypothermia (≥30°C) for the treatment of ADIAD and to report the operative outcomes of 215 patients.MethodsWe conducted a retrospective analysis of 215 consecutive cases of ADIAD treated with our new strategy.ResultsThe durations of CPB, aortic cross-clamping, antegrade cerebral perfusion, operation, mechanical ventilation support, and Intensive Care Unit stay were 139.7 ± 52.3 min, 55.6 ± 27.4 min, 14.1 ± 3.1 min, 6.0 ± 1.7 h, 40.0 h and 4.0 d, respectively. The 30-day mortality was 9.8%, with cerebral stroke occurring in nine patients (4.2%), paraplegia in one patient (0.5%) and postoperative renal injury requiring dialysis in 21 patients (9.8%). The blood transfusion of red blood cells and fresh frozen plasma during surgery and the first 24 h after surgery was 4.0 u and 200.0 ml, respectively.ConclusionsThe Brain-Heart-first strategy can be widely used with low technical and resource requirements and provides a safe alternative for conventional TAR with FET technique in ADIAD patients with satisfactory operative results.

Enbloc Heart and Lung Transplantation – A Case Report

Enbloc heart and lung transplantation is the recommended ultimate option of surgery for candidates suffering from irreversible end stage heart and lung disease. This major surgery requires a cohesive multidisciplinary teamwork approach to yield a favourable outcome. The role of perfusionist is vital in this complex operation who is an active participant in the preoperative period intra-op and post-operative period. Our Enbloc heart and lung experience - case report highlights the key elements of this surgery from the perfusionist perspective. A 68 year old male patient was suffering from end stage heart and lung disease refractory to medical therapy due to worsened interstitial lung disease and coronary artery disease. His life style was restricted and required heart and lung transplantation at the earliest. He got a suitable donor and successfully underwent Enbloc heart and lung transplantation. The donor was a 24 year old male who was in comatose state due to traumatic brain injury. The donor specific antibody test was performed and the report was negative. Cold custodial and Perfadex Plus was administered to the donor heart and lungs and were harvested. The gold standard approach for Enbloc heart and lung transplantation is the median sternotomy. Standard bicaval and aortic cannulation was done and cardiopulmonary bypass was instituted. The total Cardio Pulmonary Bypass time was 250 minutes. Cold cycle was 144 minutes and warm cycle was 75 minutes. Continuous zero balanced ultrafiltration was done to eliminate the inflammatory mediators and to keep the serum lactate within the normal limits. The various perfusion strategies involved in Enbloc heart and lung transplantation and the involvement of perfusionists in the management of these patients is discussed in the article. Enbloc heart and lung transplantation is the treatment of choice for end-stage heart and lung disease. This type of surgery demands a holistic teamwork approach involving a multidisciplinary team and this helped in the speedy recovery of the patient in the case presented.

Application of an organotypic ocular perfusion model to assess intravitreal drug distribution in human and animal eyes.

Intravitreal (ITV) drug delivery is a new cornerstone for retinal therapeutics. Yet, predicting the disposition of formulations in the human eye remains a major translational hurdle. A prominent, but poorly understood, issue in pre-clinical ITV toxicity studies is unintended particle movements to the anterior chamber (AC). These particles can accumulate in the AC to dangerously raise intraocular pressure. Yet, anatomical differences, and the inability to obtain equivalent human data, make investigating this issue extremely challenging. We have developed an organotypic perfusion strategy to re-establish intraocular fluid flow, while maintaining homeostatic pressure and pH. Here, we used this approach with suitably sized microbeads to profile anterior and posterior ITV particle movements in live versus perfused porcine eyes, and in human donor eyes. Small-molecule suspensions were then tested with the system after exhibiting differing behaviours in vivo. Aggregate particle size is supported as an important determinant of particle movements in the human eye, and we note these data are consistent with a poroelastic model of bidirectional vitreous transport. Together, this approach uses ocular fluid dynamics to permit, to our knowledge, the first direct comparisons between particle behaviours from human ITV injections and animal models, with potential to speed pre-clinical development of retinal therapeutics.

A modified perfusion protocol for pulmonary endarterectomy in a patient with a hematologic malignancy treated with a tyrosine kinase inhibitor.

Tyrosine kinase inhibitors (TKI) are known to be highly effective in the treatment of various cancers with kinase-domain mutations such as chronic myelogenous leukemia. However, they have important side effects such as increased vascular permeability and pulmonary hypertension. In patients undergoing pulmonary endarterectomy with deep hypothermic circulatory arrest, these side effects may exacerbate postoperative complications such as reperfusion edema and persistent pulmonary hypertension. We report on a simple modification of the perfusion strategy to increase intravascular oncotic pressure by retrograde autologous priming and the addition of packed cells and albumin in a patient treated with a TKI.

Perfusion Strategy for Minimally Invasive Cardiac Surgery

Minimally invasive cardiac surgery (MICS) has a number of proven advantages compared to median sternotomy. Safe cannulation and perfusion are some of the main components of the success of MICS.
 The aim. To present our perfusion strategy and describe the methods of cannulation, technical features, contraindications and potential complications.
 Materials and methods. We examined the results of 1088 adult patients who underwent primary cardiac surgery in our hospital (coronary artery bypass grafting, valve surgery, aortic surgery, left ventricle repair, congenital cardiac surgery and combined procedures) from July 2017 to May 2021. Of these, 851 patients were qualified for MICS. To select a safe cannulation strategy, we performed contrast enhanced computed tomography (CT) of the aorta and main branches for all the patients, also we calculated the body surface area according to the DuBois and DuBois formula.
 Results. We performed 838 minimally invasive on-pump procedures, which is 98.5% of all patients qualified for MICS. According to the results of the preoperative CT scan, 13 (1.5%) patients were not operated with the minimally invasive approach due to the hazards related to the provision of cardiopulmonary bypass. Peripheral cannulation was performed in 754 (90%) patients and an alternative cannulation site was selected in 62 (8.2%) patients based on preoperative CT data. There were 10 (1.32%) patients who developed major complications (stroke, acute aortic dissection, acute renal failure requiring hemodialysis) after peripheral cannulation.
 Conclusions. Preoperative CT scan is mandatory for planning a perfusion strategy in minimally invasive cardiac surgery. The required surgical techniques should include cannulation of the right and left femoral and right axillary arteries.

Primary Nonfunction of the Liver Allograft.

Severe allograft dysfunction, as opposed to the expected immediate function, following liver transplantation is a major complication, and the clinical manifestations of such that lead to either immediate retransplant or death are the catastrophic end of the spectrum. Primary nonfunction (PNF) has declined in incidence over the years, yet the impact on patient and healthcare teams, and the burden on the organ pool in case of the need for retransplant should not be underestimated. There is no universal test to define the diagnosis of PNF, and current criteria are based on various biochemical parameters surrogate of liver function; moreover, a disparity remains within different healthcare systems on selecting candidates eligible for urgent retransplantation. The impact on PNF from traditionally accepted risk factors has changed somewhat, mainly driven by the rising demand for organs, combined with the concerted approach by clinicians on the in-depth understanding of PNF, optimal graft recipient selection, mitigation of the clinical environment in which a marginal graft is reperfused, and postoperative management. Regardless of the mode, available data suggest machine perfusion strategies help reduce the incidence further but do not completely avert the risk of PNF. The mainstay of management relies on identifying severe allograft dysfunction at a very early stage and aggressive management, while excluding other identifiable causes that mimic severe organ dysfunction. This approach may help salvage some grafts by preventing total graft failure and also maintaining a patient in an optimal physiological state if retransplantation is considered the ultimate patient salvage strategy.

IGL-2 as a Unique Solution for Cold Static Preservation and Machine Perfusion in Liver and Mitochondrial Protection

Hypothermic static cold storage and machine perfusion strategies remain the clinical standard of care for liver graft preservation. Recently, the protection of the mitochondrial function and the energetic levels derived from it has emerged as one of the key points for organ preservation. However, the complex interactions between liver mitochondrial protection and its relation with the use of solutions/perfusates has been poorly investigated. The use of an alternative IGL-2 solution to Belzer MPS one for hypothermic oxygenated perfusion (HOPE), as well as in static cold storage, introduce a new kind of perfusate to be used for liver grafts subjected to HOPE strategies, either alone or in combination with hypothermic static preservation strategies. IGL-2 not only protected mitochondrial integrity, but also avoided the mixture of different solutions/perfusates reducing. Thus, the operational logistics and times prior to transplantation, a critical factor when suboptimal organs such as donation after circulatory death or steatotic ones, are used for transplantation. The future challenges in graft preservation will go through (1) the improvement of the mitochondrial status and its energetic status during the ischemia and (2) the development of strategies to reduce ischemic times at low temperatures, which should translate in a better transplantation outcome.

Cannulation Strategies in Ex Vivo Lung Perfusion.

To the Editor: Shukrallah et al.1 describe the use of donor aorta as an adjunct conduit to facilitate pulmonary artery cannulation for ex vivo lung perfusion (EVLP). As challenges pertaining to cannulation are inherent to EVLP, the article provides helpful practical content, but only considers cannulation challenges related to the pulmonary artery, and offers just a single solution that may not always suffice. In prior EVLP studies, we recognized lung cannulation challenges at both the pulmonary artery and atrial cuff and developed several novel cannulation strategies, which have been extensively described in methods and supplementary sections https://links.lww.com/ASAIO/A752.2,4–6 In ex vivo lungs, a shortened main pulmonary artery can be managed with a donor artery, vein, and/or synthetic (e.g., Dacron) graft.2 In the absence of a main pulmonary artery, donor aorta can be fashioned end-to-end to bridge the left and right pulmonary arteries, then a second graft can be anastomosed end-to-side to the donor aorta to serve as the inflow conduit (Supplemental Figure 1A https://links.lww.com/ASAIO/A752). Although optimal cannulation and perfusion strategies remain to be determined, configurations with a closed atrium have been shown to result in less edema and enhanced lung physiology.3 For EVLP circuits with a closed atrium, a shortened atrial cuff can be reconstructed using donor pericardium (Supplemental Figure 1B https://links.lww.com/ASAIO/A752), vein, or commercial soft tissue or pericardial patch products, thus enabling connection to the circuit. While many protocols use collared polymer tubing, we previously described2,4–6 the use of donor vessel as an organ-to-circuit “bio-bridge” (Supplemental Figure 1C https://links.lww.com/ASAIO/A752) to facilitate venous drainage and enable: (1) tight regulation of vascular flow, (2) consistent maintenance of pulmonary venous drainage despite differing anatomy and distribution of pulmonary veins across studies, (3) optimal placement of ex vivo lungs in prone or supine position, and (4) evaluation of oxygenation and ventilation separately in left and right lungs.4 To better understand flow characteristics through the bio-bridge, we performed computational fluid dynamics modeling, which indicated smooth laminar flow through the bio-bridge into the venous drainage cannula (Supplemental Figure 1D https://links.lww.com/ASAIO/A752).6 Immunohistochemical staining confirmed that the endothelium of the bio-bridge was intact and viable after 36 hours of normothermic cross-circulation EVLP.6 Based on these and other studies, we posit that use of the donor vessel bio-bridge as a natural vascular conduit between the organ and circuit confers demonstrable advantages due to: (1) non-thrombogenic surface and (2) intrinsic elasticity, which provides vasoprotective capacitance to dampen abrupt changes in circuit pressures.4 After more than a decade of clinical practice, the EVLP field has made remarkable progress, but still lacks standardization not only in cannulation techniques but also across platforms (e.g., commercial, custom), circuit configurations (e.g., open, closed atrium), perfusates (e.g., acellular, cellular), flow and ventilation settings, and reported parameters and outcomes. In the future, consensus guidelines should be established to help standardize cannulation and perfusion techniques and data reporting in order to facilitate rigorous cross-study comparisons and inform best practices.

Novel Organ Perfusion and Preservation Strategies in Controlled Donation After Circulatory Death in Pancreas and Kidney Transplantation

Kidney and pancreatic transplants from controlled donation after circulatory death donors are vulnerable to ischemia-reperfusion injuries. In this context of transplant shortage, there is a need to optimize the function of these transplants and to develop novel perfusion and preservation strategies in controlled donation after circulatory death in kidney and pancreatic transplants. In situ regional normothermic perfusion improves the outcome of kidney transplants from controlled donation after circulatory death and provides equivalent results for the kidney from brain-dead donors. In situ regional normothermic perfusion is under investigation for pancreatic transplants. Perfusion on hypothermic machine perfusion is highly recommended for the kidney from controlled donation after cardiac death. Hypothermic oxygenated perfusion machine decreases the rate of graft rejection and graft failure in kidney transplantation. Ex situ normothermic perfusion is an easy way to assess renal function. In the future, kidney transplants could benefit from drug therapy during ex situ normothermic perfusion. In pancreas transplantation, hypothermic machine perfusion and ex situ normothermic perfusion present encouraging results in preclinical studies.

Bifurcated Arterial Circulation for Hybrid Aortic Reconstruction: A Novel Technique.

Hybrid aortic procedures present many new challenges to the management of cardiopulmonary bypass (CPB). Reoperation or previous thoracic endovascular aortic repair (TEVAR) can further complicate these procedures, increasing the need for flexibility within the CPB system to execute multiple perfusion strategies as cases dictate. This technique describes the use of a bifurcated arterial circulation to provide both cerebral and lower body perfusion during a redo hybrid aortic arch reconstruction. The arterial line was divided into upper and lower body limbs, and connected to an 8-mm Dacron graft to the axillary artery, as well as a percutaneous 16-Fr. OptiSite femoral arterial cannula respectively. A 25-Fr. multi-stage femoral venous cannula was placed percutaneously as well. CPB was initiated utilizing both arterial cannulas with near-infrared spectroscopy and electroencephalogram to monitor the adequacy of cerebral perfusion. Moderate hypothermia of 26°C was induced and a CODA balloon (Cook Medical, Bloomington, IN) was deployed to occlude the proximal limb of a thoracic endovascular repair (TEVAR) graft; the common trunk of the debranched arch vessels was clamped proximally, allowing for simultaneous upper and lower body perfusion. Upon completion of the distal arch, the CODA balloon was removed and total body perfusion was reinitiated via central cannulation utilizing a sidearm on the arch graft.

Oxygenated machine perfusion at room temperature as an alternative for static cold storage in porcine donor hearts

BackgroundThere is a continued interest in ex situ heart perfusion as an alternative strategy for donor heart preservation. We hypothesize that oxygenated machine perfusion of donor hearts at a temperature that avoids both normothermia and deep hypothermia offers adequate and safe preservation.MethodsCardioplegia‐arrested porcine donor hearts were randomly assigned to six hours of preservation using cold storage (CS, n = 5) or machine perfusion using an oxygenated acellular perfusate at 21°C (MP, n = 5). Subsequently, all grafts were evaluated using the Langendorff method for 120 min. Metabolic parameters and histology were analyzed. Systolic function was assessed by contractility and elastance. Diastolic function was assessed by lusitropy and stiffness.ResultsFor both groups, in vivo baseline and post‐Langendorff biopsies were comparable, as were lactate difference and myocardial oxygen consumption. Injury markers gradually increased and were comparable. Significant weight gain was seen in MP (p = 0.008). Diastolic function was not impaired in MP, and lusitropy was superior from 30 min up to 90 min of reperfusion. Contractility was superior in MP during the first hour of evaluation.ConclusionWe conclude that the initial functional outcome of MP‐preserved hearts was transiently superior compared to CS, with no histological injury post‐Langendorff. Our machine perfusion strategy could offer feasible and safe storage of hearts prior to transplantation. Future studies are warranted for further optimization.

Perfusion Strategies for Neonatal Aortic Arch Surgery-Comparing AKI Risk: Apples and Apples? Or Apples and Oranges?

Perfusion Strategies for Neonatal Aortic Arch Surgery-Comparing AKI Risk: Apples and Apples? Or Apples and Oranges?