Nucleated red blood cells are a predictor of mortality in patients under extracorporeal membrane oxygenation.

BACKGROUND: The presence of Nucleated Red Blood Cells (NRBCs) in critically ill patients is associated with higher mortality and poor prognosis. Although patients on extracorporeal support such as veno-venous or veno-arterial extracorporeal membrane oxygenation (VV/VA-ECMO) are severely ill, NRBCs have rarely been investigated regarding their predictive value so far. METHODS: As part of a retrospective study, we examined all cardiothoracic surgery patients from July 2019 to September 2020 who received ECMO treatment during their inpatient stay. The aim of this study was to investigate the occurrence of NRBCs during ECMO support in terms of their predictive value for mortality. RESULTS: In total 30 patients (age at admission: 62.7 ± 14.3 year; 26 male; ECMO duration: 8.5 ± 5.1 days; ICU duration: 18.0 ± 14.5 days) were included. 16 patients (53.3%) died during their inpatient stay. There were no significant differences in demographic characteristics between VA- or VV- ECMO patients. NRBCs occurred in all patients while under ECMO support. NRBC value was significant higher in those who died (2299.6 ± 4356.6 µl) compared to the surviving patients (133.6 ± 218.8 µl, p < 0.001). Univariate analysis found that patients with a cutoff value of ≥ 270 NRBCs/µl during ECMO support were 39 times more likely to die (OR 39.0, 95% CI 1.5-997.5, p < 0.001). 12 out of 13 patients (92.3%) with ≥ 270 NRBCs/µl died. The area under the curve (AUC) of the receiver operating characteristic curve was 0.85 (95% CI 0.69-0.96) with a sensitivity of 75.0% and a specificity of 92.9%. CONCLUSION: NRBCs appear to be an accurate biomarker for mortality in patients with ECMO support. They may be helpful in deciding if therapy becomes futile. Trial registration DRKS00023626 (December 20th 2020).

Mortality rates of severe COVID-19-related respiratory failure with and without extracorporeal membrane oxygenation in the Middle Ruhr Region of Germany.

The use of extracorporeal membrane oxygenation (ECMO) is discussed to improve patients' outcome in severe COVID-19 with respiratory failure, but data on ECMO remains controversial. The aim of the study was to determine the characteristics of patients under invasive mechanical ventilation (IMV) with or without veno-venous ECMO support and to evaluate outcome parameters. Ventilated patients with COVID-19 with and without additional ECMO support were analyzed in a retrospective multicenter study regarding clinical characteristics, respiratory and laboratory parameters in day-to-day follow-up. Recruitment of patients was conducted during the first three COVID-19 waves at four German university hospitals of the Ruhr University Bochum, located in the Middle Ruhr Region. From March 1, 2020 to August 31, 2021, the charts of 149 patients who were ventilated for COVID-19 infection, were included (63.8% male, median age 67 years). Fifty patients (33.6%) received additional ECMO support. On average, ECMO therapy was initiated 15.6 ± 9.4 days after symptom onset, 10.6 ± 7.1 days after hospital admission, and 4.8 ± 6.4 days after the start of IMV. Male sex and higher SOFA and RESP scores were observed significantly more often in the high-volume ECMO center. Pre-medication with antidepressants was more often detected in survivors (22.0% vs. 6.5%; p = 0.006). ECMO patients were 14 years younger and presented a lower rate of concomitant cardiovascular diseases (18.0% vs. 47.5%; p = 0.0004). Additionally, cytokine-adsorption (46.0% vs. 13.1%; p < 0.0001) and renal replacement therapy (76.0% vs. 43.4%; p = 0.0001) were carried out more frequently; in ECMO patients thrombocytes were transfused 12-fold more often related to more than fourfold higher bleeding complications. Undulating C-reactive protein (CRP) and massive increase in bilirubin levels (at terminal stage) could be observed in deceased ECMO patients. In-hospital mortality was high (Overall: 72.5%, ECMO: 80.0%, ns). Regardless of ECMO therapy half of the study population deceased within 30 days after hospital admission. Despite being younger and with less comorbidities ECMO therapy did not improve survival in severely ill COVID-19 patients. Undulating CRP levels, a massive increase of bilirubin level and a high use of cytokine-adsorption were associated with worse outcomes. In conclusion, ECMO support might be helpful in selected severe cases of COVID-19.

[Recommendations of the S3 Guideline "Use of Extracorporeal Circulation (ECLS/ ECMO) for Cardiac and Circulatory Failure" of the Association of Scientific Medical Societies in Germany]. / Empfehlungen der S3-Leitlinie (AWMF) "Einsatz der extrakorporalen Zirkulation (ECLS/ECMO) bei Herz- und Kreislaufversagen".

In recent years, the use of mechanical support for patients with cardiac or circulatory failure has continuously increased, leading to 3,000 ECLS/ECMO (extracorporeal life support/extracorporeal membrane oxygenation) implantations annually in Germany. Due to the lack of guidelines, there is an urgent need for evidence-based recommendations addressing the central aspects of ECLS/ECMO therapy. In July 2015, the generation of a guideline level S3 according to the standards of the Association of the Scientific Medical Societies in Germany (AWMF) was announced by the German Society for Thoracic and Cardiovascular Surgery (GSTCVS). In a well-structured consensus process, involving experts from Germany, Austria and Switzerland, delegated by 16 scientific societies and the patients' representation, the guideline "Use of extracorporeal circulation (ECLS/ECMO) for cardiac and circulatory failure" was created under guidance of the GSTCVS, and published in February 2021. The guideline focuses on clinical aspects of initiation, continuation, weaning and aftercare, herein also addressing structural and economic issues. This article presents an overview on the methodology as well as the final recommendations.

Transapical-transcatheter aortic valve implantation in patients without transvascular options: Modified transapical approach.

OBJECTIVES: Outcomes in patients with iliofemoral and concomitant iliofemoral-remote arteriopathies who cannot undergo transfemoral or other alternative transvascular approaches have not been studied so far. This study aimed to evaluate the early and midterm outcomes after transapical (TA)-transcatheter aortic valve implantation (TAVI) in patients with femoral and femoral-remote arteriopathies who cannot undergo transvascular approaches. METHODS: Multimorbid patients with severe aortic stenosis and distinct panarteriopathy underwent TA-TAVI treatment between January 2012 and January 2021 at the authors' institution. Second- and third-generation self- and balloon-expanding valves were used. For patients without arterial access, TA-TAVI was modified to the artery-no-touch technique. RESULTS: Seventy-two consecutive elderly patients (78.2 ± 6.9 years; 73% male) were included in the study. The Society of Thoracic Surgery-Predicted Risk of Mortality score was 7 ± 5%. No procedural deaths or conversion to conventional surgery was registered. The 30-day and midterm mortality rates were 5% and 28%, respectively. The median time of freedom from a composite of death and cardiocerebral adverse events was 34.3 months (95% confidence interval: 17.6-51.1). The rate of moderate/severe paravalvular leakage was 0%. The pacemaker rate was 11%. CONCLUSIONS: TA-TAVI is a safe method with low-rate procedural complications and shows good early and midterm outcomes in patients with extensive panarteriopathy for whom transfemoral and other alternative transvascular approaches are contraindicated or at high interventional risk. The modified artery-no-touch TA-TAVI method is safe and feasible for selected patients with no other possible arterial approach.

Use of On-Site Digital Subtraction Angiography for Left Subclavian Artery Management During Hybrid Aortic Arch Repair in DeBakey I Dissection.

PURPOSE: A hybrid aortic repair using the frozen elephant trunk (FET) technique with an open distal anastomosis in zone 2 and debranching of the left subclavian artery (LSA) has been demonstrated to be favorable and safe. Although a transposition of the LSA reduces the risk of cerebellar or medullar ischemia, this may be challenging in difficult LSA anatomies. CASE REPORT: We present the case of a 61-year old patient with DeBakey I aortic dissection, treated with FET in moderate hypothermic circulatory arrest (26°C) and selective cerebral perfusion using a Thoraflex-Hybrid (Vascutek Terumo) prosthesis anchored in zone 2, with overstenting of the LSA orifice and no additional LSA debranching. Sufficient perfusion of the LSA was proved intraoperatively using LSA backflow analysis during selective cerebral perfusion in combination with on-site digital subtraction angiography (ARTIS Pheno syngo software). No neurologic dysfunction or ischemia occurred in the postoperative course. An angiographic computed tomography revealed physiologic LSA perfusion, with subsequent thrombotic occlusion of the false lumen in the proximal descending aorta after 7 days. CONCLUSION: Using an angiography-guided management in patients with complex DeBakey I dissection and difficult anatomy may simplify a proximalization of the distal anastomosis in zone 2 for FET, even without an additional LSA debranching.

Use of extracorporeal circulation (ECLS/ECMO) for cardiac and circulatory failure -A clinical practice Guideline Level 3.

Aims Worldwide applications of extracorporeal circulation for mechanical support in cardiac and circulatory failure, which are referred to as extracorporeal life support (ECLS) or veno-arterial extracorporeal membrane oxygenation (va-ECMO), have dramatically increased over the past decade. In spite of the expanding use and the immense medical as well as socio-economic impact of this therapeutic approach, there has been a lack of interdisciplinary recommendations considering the best available evidence for ECLS treatment. Methods and Results In a multiprofessional, interdisciplinary scientific effort of all scientific societies involved in the treatment of patients with acute cardiac and circulatory failure, the first evidence- and expert consensus-based guideline (level S3) on ECLS/ECMO therapy was developed in a structured approach under regulations of the AWMF (Association of the Scientific Medical Societies in Germany) and under use of GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria. This article presents all recommendations created by the expert panel, addressing a multitude of aspects for ECLS initiation, continuation, weaning and aftercare as well as structural and personnel requirements. Conclusions This first evidence- and expert consensus-based guideline (level S3) on ECLS/ECMO therapy should be used to apply the best available care nationwide. Beyond clinical practice advice, remaining important research aspects for future scientific efforts are formulated.

[Use of extracorporeal circulation (ECLS/ECMO) for cardiac and circulatory failure : Short version of the S3 guideline]. / Einsatz der extrakorporalen Zirkulation (ECLS/ECMO) bei Herz- und Kreislaufversagen : Kurzversion der AWMF-S3-Leitlinie.

In Germany, a remarkable increase regarding the usage of extracorporeal membrane oxygenation (ECMO) and extracorporeal life support (ECLS) systems has been observed in recent years with approximately 3000 ECLS/ECMO implantations annually since 2015. Despite the widespread use of ECLS/ECMO, evidence-based recommendations or guidelines are still lacking regarding indications, contraindications, limitations and management of ECMO/ECLS patients. Therefore in 2015, the German Society of Thoracic and Cardiovascular Surgery (GSTCVS) registered the multidisciplinary S3 guideline "Use of extracorporeal circulation (ECLS/ECMO) for cardiac and circulatory failure" to develop evidence-based recommendations for ECMO/ECLS systems according to the requirements of the Association of the Scientific Medical Societies in Germany (AWMF). Although the clinical application of ECMO/ECLS represents the main focus, the presented guideline also addresses structural and economic issues. Experts from 17 German, Austrian and Swiss scientific societies and a patients' organization, guided by the GSTCVS, completed the project in February 2021. In this report, we present a summary of the methodological concept and tables displaying the recommendations for each chapter of the guideline.

[Use of extracorporeal circulation (ECLS/ECMO) for cardiac and circulatory failure : Short version of the S3 guideline]. / Einsatz der extrakorporalen Zirkulation (ECLS/ECMO) bei Herz- und Kreislaufversagen : Kurzversion der AWMF-S3-Leitlinie.

In Germany, a remarkable increase regarding the usage of extracorporeal membrane oxygenation (ECMO) and extracorporeal life support (ECLS) systems has been observed in recent years with approximately 3000 ECLS/ECMO implantations annually since 2015. Despite the widespread use of ECLS/ECMO, evidence-based recommendations or guidelines are still lacking regarding indications, contraindications, limitations and management of ECMO/ECLS patients. Therefore in 2015, the German Society of Thoracic and Cardiovascular Surgery (GSTCVS) registered the multidisciplinary S3 guideline "Use of extracorporeal circulation (ECLS/ECMO) for cardiac and circulatory failure" to develop evidence-based recommendations for ECMO/ECLS systems according to the requirements of the Association of the Scientific Medical Societies in Germany (AWMF). Although the clinical application of ECMO/ECLS represents the main focus, the presented guideline also addresses structural and economic issues. Experts from 17 German, Austrian and Swiss scientific societies and a patients' organization, guided by the GSTCVS, completed the project in February 2021. In this report, we present a summary of the methodological concept and tables displaying the recommendations for each chapter of the guideline.

Hemoadsorption: effective in reducing circulating fragments of the endothelial glycocalyx during cardiopulmonary bypass in patients undergoing on-pump cardiac surgery?

BACKGROUND: The vascular endothelial glycocalyx is susceptible to ischemia and hypoxia. Released soluble components of the endothelial glycocalyx (EG) have been identified as potential damage associated molecular patterns (DAMPs) able to enhance an ongoing inflammatory response. Shedding of the EG has been associated with released atrial-natriuretic peptide (ANP) during cardiac surgery procedures. A novel hemoadsorption technique (CytoSorb®) has been shown to effectively remove molecules up to 55 kDa unspecifically from circulation. It is not known whether ANP or glycocalyx components can be removed successfully by this technique. METHODS: In 15 patients undergoing on-pump cardiac surgery, the hemoadsorption device was integrated in the cardiopulmonary bypass (CPB) circuit. Pre- and post-adsorber concentrations of ANP, heparan sulphate (HEP), syndecan-1 (SYN) and hyaluronan (HYA) were measured at 10 (T1), 30 (T2), and 60 (T3) minutes after aortic cross-clamping and complete CPB. RESULTS: Hemoadsorption significantly reduced mean HEP concentrations (-157.5 [333.4] ng/mL; P<0.001) post adsorber. For ANP and SYN no statistically significant changes were detected whereas mean [SD] HYA concentrations even increased significantly (+21.6 [43.0] ng/mL; P<0.001) post adsorber. CONCLUSIONS: In this study representing a real-life scenario, we could demonstrate that the novel hemoadsorption device (CytoSorb®) was able to effectively adsorb HEP from the circulation if integrated in a CPB circuit. However, blood concentrations of HYA, SYN, and ANP could not be reduced during CPB in our investigation.

Extracorporeal membrane oxygenation for acute respiratory distress syndrome in burn patients: a case series and literature update.

BACKGROUND: Acute respiratory distress syndrome (ARDS) has a reported incidence of 34-43% in ventilated burn patients and is associated with a mortality of 59% in the severe form. The use and experience with extracorporeal membrane oxygenation (ECMO) in burn patients developing ARDS are still limited. We present our results and discuss the significance of ECMO in treating burn patients. METHODS: A retrospective analysis of burn patients treated with ECMO for ARDS between January 2017 and January 2019 was performed. Demographic, clinical, and outcome data were collected and analyzed. RESULTS: Eight burn patients were treated at our institution with ECMO in the designated time period. Of these, all but one patient had inhalation injury, burn percentage of TBSA was 37 ± 23%, ABSI score was 8.4 ± 2, and R-Baux-score was 98 ± 21. Seven patients developed severe ARDS and one patient moderate ARDS according to the Berlin classification with a PaO2/FiO2 ratio upon initiation of ECMO therapy of 62 ± 22 mmHg. ECMO duration was 388 ± 283 h. Three patients died from severe sepsis while five patients survived to hospital discharge. CONCLUSIONS: ECMO is a viable therapy option in burn patients developing severe ARDS and can contribute to survival rates similar to ECMO therapy in non-burn-associated severe ARDS. Consequently, patients with severe respiratory insufficiency with unsuccessful conventional treatment and suspected worsening should be transferred to burn units with the possibility of ECMO treatment to improve outcome.

Two-stage weaning strategy using veno-veno-arterial perfusion for patients on extracorporeal membrane oxygenation following cardiogenic shock.

OBJECTIVES: Veno-arterial extracorporeal membrane oxygenation represents the last therapy option in refractory cardiogenic shock. Successful weaning becomes difficult if the myocardial function recovers but pulmonary impairment persists. We present our experience with a new weaning strategy, using a stepwise mode-switch from veno-arterial to veno-veno-arterial and veno-venous extracorporeal membrane oxygenation setting for patients with primary cardiogenic shock and subsequent respiratory failure. METHODS: From 81 patients treated with veno-arterial extracorporeal membrane oxygenation following acute cardiogenic shock between January 2014 and April 2018, eight patients with cardiac and pulmonary failure were identified to be treated using the following protocol: patients were put on veno-arterial extracorporeal membrane oxygenation, a second inflow cannula was inserted via the right jugular vein and cardiac weaning was performed via veno-veno-arterial support. Finally, patients were pulmonary weaned via veno-venous extracorporeal membrane oxygenation mode. RESULTS: In the mode-switch group, etiologies of cardiogenic shock were cardiac arrest (12.5%), myocardial infarction (12.5%) and post-cardiotomic heart failure (75%). Mean time between onset of cardiogenic shock and start of veno-arterial extracorporeal membrane oxygenation was 76 ± 117 min. At implantation, lactate and pH values were 9.5 ± 5.0 mmol/L and 7.2 ± 0.2. Total extracorporeal membrane oxygenation-time was 9.3 ± 4.7 days, with a mode-switch from veno-arterial to veno-veno-arterial after 3.9 ± 2.7 days. The weaning rate in the mode-switch group was 75% (vs. 41% in the entire cohort) and the 30-day survival was 50% (vs 32% in the cohort). 38% of the patients presented a favorable neurological outcome. CONCLUSION: Mode-switch from veno-arterial to veno-veno-arterial and weaning via veno-venous extracorporeal membrane oxygenation mode is feasible for combined cardiac and pulmonary failure, with promising results due to an optimized pre-pulmonary oxygenation.

Goal-directed perfusion to reduce acute kidney injury: A randomized trial.

OBJECTIVE: To determine whether a goal-directed perfusion (GDP) strategy aimed at maintaining oxygen delivery (DO2) at ≥280 mL·min-1·m-2 reduces the incidence of acute kidney injury (AKI). METHODS: This multicenter randomized trial enrolled a total of 350 patients undergoing cardiac surgery in 9 institutions. Patients were randomized to receive either GDP or conventional perfusion. A total of 326 patients completed the study and were analyzed. Patients in the treatment arm were treated with a GDP strategy during cardiopulmonary bypass (CPB) aimed to maintain DO2 at ≥280 mL·min-1·m-2. The perfusion strategy for patients in the control arm was factored on body surface area and temperature. The primary endpoint was the rate of AKI. Secondary endpoints were intensive care unit length of stay, major morbidity, red blood cell transfusions, and operative mortality. RESULTS: Acute Kidney Injury Network (AKIN) stage 1 was reduced in patients treated with GDP (relative risk [RR], 0.45; 95% confidence interval [CI], 0.25-0.83; P = .01). AKIN stage 2-3 did not differ between the 2 study arms (RR, 1.66; 95% CI, 0.46-6.0; P = .528). There were no significant differences in secondary outcomes. In a prespecified analysis of patients with a CPB time between 1 and 3 hours, the differences in favor of the treatment arm were more pronounced, with an RR for AKI of 0.49 (95% CI, 0.27-0.89; P = .017). CONCLUSIONS: A GDP strategy is effective in reducing AKIN stage 1 AKI. Further studies are needed to define perfusion interventions that may reduce more severe levels of renal injury (AKIN stage 2 or 3).

Scabies outbreak among healthcare workers in a German acute care hospital.

BACKGROUND: This article reports on a scabies outbreak among healthcare workers (HCW) in an acute care hospital. The outbreak was associated with a patient suffering from a chronic skin disease that was later diagnosed as crusted scabies. OBJECTIVE: The objective was to determine the outbreak drivers and define a prevention strategy against future outbreaks. METHODS: All staff that had contact with the patient were treated with 5% permethrin ointment. An interdisciplinary outbreak investigation team was established. The team conducted a questionnaire-based case-control study. FINDINGS: After the permethrin treatment, no further case was found. Twenty-seven HCWs who had contact with the index patient answered the questionnaire (response rate 73%). The outbreak questionnaire revealed 13 cases of secondary scabies among HCWs. In the multivariable analysis, a lack of glove use (odds ratio [OR], 9.8; P value = 0.036) and frequent close physical contact (OR, 8.151; P value = 0.038) were associated with increased risk of scabies acquisition. DISCUSSION: The scabies outbreak was most likely driven by three factors: an index patient with crusted scabies; a delayed diagnosis of this patient; and close physical contact without gloves during his hospital stay. The use of disposable gloves for patients with unclear dermatological diagnosis have the potential to limit future scabies outbreaks.

Extracorporeal membrane oxygenation in spina bifida and (H1N1)-induced acute respiratory distress syndrome.

Acute respiratory distress syndrome (ARDS) is characterized as an acute hypoxemic and/or hypercapnic respiratory failure seen in critically ill patients and is still, although decreased over the past few years, associated with high mortality. Furthermore, ARDS may be a life-threatening complication of H1N1 pneumonia. We report on a 45-year-old spina bifida patient with confirmed H1N1 influenza virus infection causing acute respiratory failure, who was successfully weaned from 42-day veno-venous extracorporeal membrane oxygenation (vv-ECMO) treatment with an excellent outcome. Due to the physical constitution of spina bifida patients, we experienced challenges concerning cannula positioning and mechanical ventilation settings during weaning.

Effect of body mass index on the outcome of surgical patients receiving extracorporeal devices (VV ECMO, pECLA) for respiratory failure.

INTRODUCTION: To determine whether obese surgical patients are at a significant disadvantage in terms of outcomes after extracorporeal device (ECD) support, such as veno-venous extracorporeal membrane oxygenation (VV ECMO) or pumpless extracorporeal lung assist (pECLA), for respiratory failure, the relationship between body mass index (BMI) and hospital outcomes was analyzed. METHODS: This retrospective study included data on patients who were supported with an ECD between January 1, 2008 and December 31, 2014. The analysis included 89 patients (74 male). RESULTS: The median BMI was 30 kg/m2 (19-88.5). The median duration of the ECD support was 9.0 days, with a maximum of 37.1 days. The median LOS (length of stay) in the intensive care unit (ICU) was 21 days (range 0.06-197.6). The median hospital LOS was 34.9 days (range 0.1-213.8). VV ECMO was performed 72 times, and pECLA was performed 18 times. The number of patients successfully weaned off the ECD was 54 (60.6%). Survival at the discharge from the hospital was 48.3%. CONCLUSIONS: 54 (60.6%) patients were successfully weaned off the ECD; 43 (48.3%) patients survived and were discharged from the hospital. The analysis of correlations between BMI and outcomes of surgical patients treated with ECD showed no association between BMI and mortality. Complications (especially oxygenator clotting) were not more frequent in obese and extremely obese patients. We hypothesized that patients with higher or morbid BMIs would have increased mortality after ECD support. A BMI of 30.66 kg/m2 corresponded to the desired sensitivity and specificity to predict mortality. This finding applied only to the study group. Treatment with ECD in obese patients presents unique challenges, including percutaneous cannulation and increased staff requirements. However, based on these data, obesity should not be an exclusion criterion for ECD therapy.

RECCAS - REmoval of Cytokines during CArdiac Surgery: study protocol for a randomised controlled trial.

BACKGROUND: On-pump cardiac surgery triggers a significant postoperative systemic inflammatory response, sometimes resulting in multiple-organ dysfunction associated with poor clinical outcome. Extracorporeal cytokine elimination with a novel haemoadsorption (HA) device (CytoSorb®) promises to attenuate inflammatory response. This study primarily assesses the efficacy of intraoperative HA during cardiopulmonary bypass (CPB) to reduce the proinflammatory cytokine burden during and after on-pump cardiac surgery, and secondarily, we aim to evaluate effects on postoperative organ dysfunction and outcomes in patients at high risk. METHODS/DESIGN: This will be a single-centre randomised, two-arm, patient-blinded trial of intraoperative HA in patients undergoing on-pump cardiac surgery. Subjects will be allocated to receive either CPB with intraoperative HA or standard CPB without HA. The primary outcome is the difference in mean interleukin 6 (IL-6) serum levels between the two study groups on admission to the intensive care unit. A total number of 40 subjects was calculated as necessary to detect a clinically relevant 30 % reduction in postoperative IL-6 levels. Secondary objectives evaluate effects of HA on markers of inflammation up to 48 hours postoperatively, damage to the endothelial glycocalyx and effects on clinical scores and parameters of postoperative organ dysfunction and outcomes. DISCUSSION: In this pilot trial we try to assess whether intraoperative HA with CytoSorb® can relevantly reduce postoperative IL-6 levels in patients undergoing on-pump cardiac surgery. Differences in secondary outcome variables between the study groups may give rise to further studies and may lead to a better understanding of the mechanisms of haemoadsorption. TRIAL REGISTRATION: German Clinical Trials Register number DRKS00007928 (Date of registration 3 Aug 2015).

Spinal cord ischemia after selective cerebral perfusion in a porcine "frozen elephant trunk" simulation model.

BACKGROUND: The "frozen elephant trunk" procedure (FET) represents the therapy of choice for extended aortic diseases. The aim of our study was to analyze whether 90 minutes of selective cerebral perfusion (SCP) at 28 °C followed by permanent occlusion of the thoracic segmental arteries (TSA) would cause spinal cord ischemia in a porcine model. METHODS: 14 pigs (41 ± 3 kg) were cooled on CPB to 28 °C. After aortic clamping, SCP was established for 90 minutes. Randomly, in 7 animals the TSA were clipped (T4-T13); the TSA of 7 animals remained untouched. After the animals were weaned from CPB, hemodynamic data were registered for 120 minutes. Regional spinal cord blood flow (SCBF) was calculated, and motor-evoked potentials (MEP) were assessed at 6 time points. After sacrifice of the animals, the spinal cord was analyzed histologically by use of a schematic grading system (0 = normal; 8 = total necrosis). RESULTS: During SCP the SCBF was maintained at baseline (5.9 ± 2.4 mL/min/100 g) in the T4-T13 region but showed a decrease (from 8.4 ± 4.3 to 1.3 ± 1.5 mL/min/100 g) in the L1-L5 region. During reperfusion it increased, with two to three times higher values in the nonclipped animals. After 90 minutes of SCP, the MEP reached lower levels in the L1-L5 region of the TSA-clipped animals: 59% ± 7% vs 84 ± 15% (vastus medialis muscle) and 48% ± 6% vs 82% ± 26% (tibialis anterior muscle). The MEP recovered only in the nonclipped group. Higher ischemia rates were seen in the L1-L5 region of the TSA-clipped animals (score: 6.0 ± 0.6 vs 2.5 ± 2.3). CONCLUSIONS: 90 minutes of SCP provided sufficient spinal cord protection during arch replacement at 28 °C. In combination with permanent TSA occlusion, the lumbar spinal cord perfusion may be altered, which causes functional and structural damage.