Minimal Extracorporeal Circulation and Microplegia in the Setting of Urgent Coronary Artery Bypass Grafting.

Background: We aimed to analyse the performance of minimal invasive extracorporeal circulation (MiECC) concomitantly with Microplegia, in patients with recent myocardial infarction (MI) undergoing urgent coronary artery bypass grafting (CABG) surgery. Methods: We included patients with a recent MI (≤7 days) undergoing isolated CABG surgery using MiECC. The primary endpoint was a major cardiovascular or cerebrovascular event (MACCE). In a secondary analysis, we compared our institutional Microplegia concept with the use of a crystalloid single-shot cardioplegic solution. Results: In total, 139 patients (mean ± standard deviation (SD) age 66 ± 10 years) underwent urgent CABG surgery using Microplegia; 55% (n = 77) of the patients had an acute MI within 1−7 days preoperatively; 20% (n = 28) had an acute MI within 6−24 h; and 24% (n = 34) had an acute MI within <6 h preoperatively. The number of distal anastomoses was a geometric mean of 4 (95% confidence interval 3−4). The MACCE and in-hospital mortality were 7% (n = 10) and 1% (n = 2), respectively. The results were confirmed in a secondary analysis comparing Microplegia with crystalloid cardioplegic solution (n = 271). Conclusion: The use of MiECC with Microplegia in urgent CABG surgery is feasible and safe and provides a straight-forward intraoperative setting. Therefore, it can also be considered to retain the benefits of MiECC in urgent CABG surgery.

Case Report: Left Ventricular Unloading Using a Mechanical CPR Device in a Prolonged Accidental Hypothermic Cardiac Arrest Treated by VA-ECMO - a Novel Approach.

We recently treated a 36-year-old previously healthy male with a prolonged hypothermic (lowest temperature 22.3°C) cardiac arrest after an alcohol intoxication with a return of spontaneous circulation after 230min of mechanical cardiopulmonary resuscitation and rewarming by veno-arterial ECMO with femoral cannulation and retrograde perfusion of the aortic arch. Despite functional veno-arterial ECMO, we continued mechanical cardiopulmonary resuscitation (Auto Pulse™ device, ZOLL Medical Corporation, Chelmsford, USA) until return of spontaneous circulation to prevent left ventricular distention from persistent ventricular fibrillation. The case was further complicated by extensive trauma caused by mechanical cardiopulmonary resuscitation (multiple rib fractures, significant hemothorax, and a liver laceration requiring massive transfusion), lung failure necessitating a secondary switch to veno-venous ECMO, and acute kidney injury with the need for renal replacement therapy. Shortly after return of spontaneous circulation, the patient was already following commands and could be discharged 3 weeks later without neurologic, cardiac, or renal sequelae and being entirely well. Prolonged accidental hypothermic cardiac arrest might present with excellent outcomes when supported with veno-arterial ECMO. Until return of spontaneous circulation, one might consider continuing with mechanical cardiopulmonary resuscitation in addition to ECMO to allow some left ventricular unloading. However, the clinician should keep in mind that prolonged mechanical cardiopulmonary resuscitation may cause severe injuries.

5-year results of a newly implemented mechanical circulatory support program for terminal heart failure patients in a Swiss non-cardiac transplant university hospital.

BACKGROUND: In Switzerland, long-term circulatory support programs have been limited to heart transplant centers. In 2014, to improve the management of patients with end-stage heart failure not eligible for transplantation, we implemented a left ventricular assist device (LVAD) program for destination therapy at the University Hospital of Basel. METHODS: We described the program set-up with practical aspects. Patients aged 65 and above with therapy refractory end-stage heart failure without major contraindication for LVAD implantation were included. Younger patients with bridge-to-candidacy profile were also considered. Using the Kaplan-Meier estimate, we retrospectively analyzed the overall survival and freedom from major adverse events after LVAD implantation. We compared our results to internationally reported data. RESULTS: Between October 2014 and September 2019, 16 patients received an LVAD in our center. The mean age at implantation was 67.1 years. The mean EuroSCORE II was 24.4% and the median INTERMACS level was 4. Thirteen patients received an LVAD as destination therapy and three patients as bridge-to-candidacy. The overall survival was 87.5 and 70% at 1 and 2 years, respectively. Freedom from stroke was 81.3% at 1 and 2 years. Freedom from device infection was 67.7 and 58.7% at 1 and 2 years, respectively. Freedom from gastrointestinal bleeding was 75 and 56.3% at 1 and 2 years, respectively. Freedom from readmission was 50 and 31.3% and at 6 months and 1 year, respectively. CONCLUSIONS: The Basel experience demonstrated the possible implementation of an LVAD program for destination therapy or bridge-to-candidacy in a non-transplant comprehensive heart-failure center with midterm survival results and freedom from major adverse events comparable to international registries. Patient selection remains crucial. TRIAL REGISTRATION: This study was registered on the ClinicalTrials.gov database ( NCT04263012 ).

Lean Ad hoc Extracorporeal Membrane Oxygenation Systems for COVID-19.

Coronavirus disease (COVID-19) is overwhelming hospitals with patients requiring respiratory support, including ventilators and Extracorporeal Membrane Oxygenation (ECMO). Bottlenecks in device availability may contribute to mortality, and limited device availability even in ECMO centers has led to rationing recommendations. Therefore, we explored options for ad hoc construction of venovenous ECMO using readily available components, essentially, large cannulas, membrane oxygenators, and blood pumps. As thousands of certified cardiac Impella pumps are distributed worldwide, we assembled lean ECMO by embedding Impella pumps coaxially in tubes, combined with standard gas exchangers. Ad hoc integration of Impella blood pumps with gas exchange modules, large-bore venous cannulas, regular ECMO tubing, Y-pieces, and connectors led to lean ECMO systems with stable performance over several days. Oxygenation of 2.5-5 L of blood per minute is realistic. Benefit/risk analysis appears favorable if a patient needs respiratory support but required support systems in a center are exhausted. Ad hoc assembly of venovenous ECMO is feasible using Impella blood pumps, results in stable blood flow across gas exchange modules, and thus may offer another opportunity to oxygenate, "recover the lungs" and hopefully save lives in selected patients with severe COVID-19 disease even when conventional life support equipment is exhausted. The lean design also yields inspirations for future ECMO systems.

Analysis of Myocardial Ischemia Parameters after Coronary Artery Bypass Grafting with Minimal Extracorporeal Circulation and a Novel Microplegia versus Off-Pump Coronary Artery Bypass Grafting.

BACKGROUND: To compare the performance of our institutionally refined microplegia protocol in conjunction with minimal extracorporeal circulation system (MiECC) with off-pump coronary artery bypass grafting (OPCAB). METHODS: We conducted a single center study including patients undergoing isolated CABG surgery performed either off-pump or on-pump using our refined microplegia protocol in conjunction with MiECC. We used propensity modelling to calculate the inverse probability of treatment weights (IPTW). Primary endpoints were peak values of high-sensitivity cardiac troponin T (hs-cTnT) during hospitalization, and respective first values on the first postoperative day. Endpoint analysis was adjusted for intraoperative variables. RESULTS: After IPTW, we could include 278 patients into our analyses, 153 of which had received OPCAB and 125 of which had received microplegia. Standardized differences indicated that treatment groups were comparable after IPTW. The multivariable quantile regression yielded a nonsignificant median increase of first hs-cTnT by 39 ng/L (95% CI -8 to 87 ng/L, p = 0.11), and of peak hs-cTnT by 35 ng/L (CI -13 to 84, p = 0.11), and of peak hs-cTnT by 35 ng/L (CI -13 to 84, p = 0.11), and of peak hs-cTnT by 35 ng/L (CI -13 to 84, p = 0.11), and of peak hs-cTnT by 35 ng/L (CI -13 to 84. CONCLUSION: The use of our institutionally refined microplegia in conjunction with MiECC was associated with similar results with regard to ischemic injury, expressed in hs-cTnT compared to OPCAB. MACCE was seen equally frequent. ICU discharge was earlier if microplegia was used.

Bretschneider (Custodiol®) and St. Thomas 2 Cardioplegia Solution in Mitral Valve Repair via Anterolateral Right Thoracotomy: A Propensity-Modelled Comparison.

BACKGROUND: Single-dose cardioplegia is preferred in minimal invasive mitral valve surgery to maintain the adjustment of the operative site without change of preset visualization. The aim of our study was to compare two widely used crystalloid cardioplegias Bretschneider (Custodiol®) versus St. Thomas 2 in patients who underwent mitral valve repair via small anterolateral right thoracotomy. MATERIAL AND METHODS: From May 2012 until February 2019, 184 isolated mitral valve procedures for mitral valve repair via anterolateral right thoracotomy were performed using Bretschneider (Custodiol®) cardioplegia (n = 123) or St. Thomas (n = 61). Primary efficacy endpoint was peak postoperative high-sensitivity cardiac troponin (hs-cTnT) during hospitalization. Secondary endpoints were peak creatine kinase-muscle brain type (CK-MB) and creatine kinase (CK) as well as safety outcomes. We used inverse probability of treatment weighting (IPTW) in order to adjust for confounding by indication. RESULTS: Peak hs-cTnT was higher after use of Bretschneider (Custodiol®) (geometric mean 716 mg/L, 95% confidence interval (CI) 605-847 mg/L) vs. St. Thomas 2 (561 mg/L, CI 467-674 mg/L, p = 0.047). Peak CK-MB (geometric mean after Bretschneider (Custodiol®): 40 µg/L, CI 35-46, St. Thomas 2: 33 µg/L, CI 27-41, p = 0.295) and CK (geometric mean after Bretschneider (Custodiol®): 1370 U/L, CI 1222-1536, St. Thomas 2: 1152 U/L, CI 972-1366, p = 0.037) showed the same pattern. We did not see any difference with respect to postoperative complications between treatment groups after IPTW. CONCLUSION: Use of St. Thomas 2 cardioplegia was associated with lower postoperative peak levels of all cardiac markers that reflect cardiac ischemia such as hs-cTnT, CK, and CK-MB as compared to Bretschneider (Custodiol®) in propensity-weighted treatment groups.

Clinical implementation of a novel myocardial protection pathway in coronary artery bypass surgery with minimal extracorporeal circulation.

INTRODUCTION: The aim of this study was to report the clinical implementation of the joint use of the Myocardial Protection System (MPS®) and the minimal extracorporeal circulation system (MiECC), in conjunction with an institutionally refined dose/volume-dependent microplegia in coronary artery bypass grafting (CABG). METHODS: Patients with isolated CABG surgery were included. The final protocol to achieve cardioplegic arrest consisted of warm blood cardioplegia with 20 mmol potassium (K), 1.6 g magnesium (Mg) and 40 mg lidocaine per liter (L) blood. We prospectively collected intra- and postoperative data to monitor and validate this novel approach. RESULTS: Eighty patients were operated accordingly. Mean (SD) aortic clamping time and extracorporeal perfusion time were 67.5 (22.6) and 101.1 (31.9) minutes, respectively. Failure to induce cardiac arrest was seen in six patients at the early stage of refinement of the formula. Median (IQR) high -sensitivity cardiac troponin T (hs-cTnT) on the first postoperative day (POD) and peak hs-cTnT were 262.5 ng/L (194.3-405.8) and 265.5 ng/L (194.3-405.8), respectively. Median (IQR) creatine kinase-myocardial type (CK-MB) on POD 1 and peak CK-MB were 14.2 µg/L (10.5-22.7) and 14.2 µg/L (10.7-23.2), respectively. Median (IQR) creatine kinase (CK) on POD 1 and peak CK were 517.5 U/L (389.3-849.8) and 597.5 U/L (455.0-943.0), respectively. No patient died during hospitalization. CONCLUSIONS: The combination of this cardioplegic formula with MPS® and MiECC in CABG was safe and feasible. With the final chemical makeup, cardiac arrest was reliably achieved. Remarkably low postoperative cardiac markers indicate shielded cardiac protection during surgery.

Point-of-care coagulation management algorithms during ECMO support: are we there yet?

Haemorrhagic and thromboembolic events are common and the main cause for morbidity and mortality in patients treated with extracorporeal membrane oxygenation (ECMO). Monitoring of an adequate anticoagulation is, therefore, essential in patients during ECMO therapy. This review aims to describe the current evidence and emerging data relating to anticoagulation therapy and point-of-care (POC) coagulation monitoring in ECMO patients. Central laboratory-based coagulation testing including activated partial thromboplastin time (aPTT), international normalized ratio (INR) of the prothrombin time (PT), and activated clotting time (ACT) is most commonly used for coagulation monitoring. Several lines of coagulation monitoring devices have been explored for POC assessment of anticoagulation and/or haemostasis during ECMO. POC-type ACT, aPTT and PT have a shorter turn-around time, but they might exhibit a relevant bias in agreement with laboratory-based coagulation tests, and sensitivity and specificity for intervention are variable compared with laboratory- based tests. Whole-blood viscoelastic coagulation tests including ROTEM® and TEG® and platelet function testing have been increasingly used for monitoring haemostasis in ECMO patients. However, no single laboratory-based or POC coagulation test can reliably predict the emergence of haemorrhagic or thrombotic events. Further, treatment algorithms based on POC testing are scarce for ECMO patients. Larger prospective studies are necessary to evaluate the usefulness of POC coagulation monitors or a combination of them in potentially improving anticoagulation and decreasing haemorrhagic and thromboembolic complications.

Reduced aspirin responsiveness as assessed by impedance aggregometry is not associated with adverse outcome after cardiac surgery in a small low-risk cohort.

Reduced aspirin responsiveness (i.e. persistent high platelet reactivity in platelet function testing) might be associated with increased risk of myocardial ischemia and cardiac mortality in patients with coronary disease. However, the impact in patients undergoing coronary artery bypass grafting (CABG) is unclear. The aim of this prospective cohort study was to evaluate the predictive value of reduced aspirin responsiveness on cardiac and thromboembolic events in patients undergoing elective isolated CABG surgery with aspirin intake until at least two days before surgery. We included 304 patients in this prospective single-center cohort study. Impedance platelet aggregometry (Multiplate®) was performed directly before and on the first day after surgery. Reduced aspirin responsiveness was defined as area under the curve in ASPItest (AUCASPI) ≥300 U. The primary outcome was a composite of all-cause mortality and/or major adverse cardiac or thromboembolic events within 1 year. Reduced aspirin responsiveness was found in 13 and 24% of patients pre and postoperatively, respectively. There was no difference in the outcomes between patients with normal and reduced aspirin responsiveness in the preoperative measurement (log-rank test, p = 0.540). Multivariate analysis including logistic EuroSCORE I and postoperative troponin T levels did not show any association of reduced aspirin responsiveness with adverse outcome (hazard ratio, 0.576; (95% CI 0.128-2.585; p = 0.471). Similarly, postoperative reduced aspirin responsiveness was not associated with adverse events. To conclude, reduced aspirin responsiveness as evaluated by Multiplate® platelet function analyzer was not associated with increased incidence of major adverse cardiac and thromboembolic events and mortality after CABG surgery.

Transfusion of allogeneic blood products in proximal aortic surgery with hypothermic circulatory arrest: effect of thromboelastometry-guided transfusion management.

OBJECTIVES: Proximal aortic surgery with hypothermic circulatory arrest (HCA) commonly involves perioperative transfusion of allogeneic blood products, including red blood cells, plasma, and platelets. The authors hypothesized that surgery with HCA could be performed without allogeneic blood products and that a thromboelastometry-guided algorithm would reduce the transfusion of allogeneic blood products. DESIGN: A retrospective analysis of prospectively collected data. Patients with and without thromboelastometry guidance were compared by case-control analysis (n = 62 matched patients) and multivariate regression (n = 194 patients). SETTING: Single-center university hospital. PARTICIPANTS: This study included 194 patients undergoing elective and emergent procedures with HCA involving the proximal aorta. INTERVENTIONS: A thromboelastometry-guided treatment algorithm during surgery was used in 153 patients (79%), and conventional coagulation management was used in 41 patients (21%). MEASUREMENTS AND MAIN RESULTS: During surgery and the following 24 hours, allogeneic blood products were transfused in 106 patients (55%). Median (interquartile range) number of allogeneic blood products transfused was 1 unit (0-6 units). Case-control analysis showed lower transfusion rates of red blood cells, plasma, and any allogeneic blood product (all p<0.050) in patients with thromboelastometry guidance. In the multivariate analysis, thromboelastometry guidance was associated with an odds ratio of 0.26 (95% confidence interval, 0.08-0.84; p = 0.025) for the transfusion of any allogeneic blood product. The use of thromboelastometry was not associated with adverse events (odds ratio 0.72; 95% confidence interval, 0.27-1.90; p = 0.507). CONCLUSIONS: Allogeneic blood products were avoided in a proportion of patients. The findings further suggest that thromboelastometry-guided coagulation management promoting the use of coagulation factor concentrates decreased the use of allogeneic blood products during complex cardiac surgery.

Pre-analytical effects of pneumatic tube transport on impedance platelet aggregometry.

Point-of-care platelet monitoring is increasingly used in cardiac patients treated with antiplatelet agents. The validity of a new assay needs to be evaluated not only for reproducible data in clinical samples, but also for other pre-analytical conditions that may influence measurements. The aim of this study was to evaluate the influence of a pneumatic tube system (PTS) for specimen transport on impedance platelet aggregometry. We evaluated 50 consecutive patients scheduled for coronary artery bypass surgery under oral therapy with 100 mg/d acetylsalicylic acid (aspirin). In each patient, three blood samples for platelet function analysis were taken before induction of anesthesia. The first sample was measured in the operating room (OR) area and designated as the reference value. The second sample was again measured by the same operator in the OR area using a random PTS transport. The third sample was sent to the central laboratory by PTS where it was measured by a local technician. Platelet function was assessed in whole blood by impedance aggregometry with a Multiplate analyzer using thrombin-related activation peptide (TRAP test) and arachidonic acid (ASPI test) (Dynabite GmbH, Munich, Germany). Mean +/- SD for TRAP test was 1009 +/- 196 in the reference measurement. Bias +/- 95% limit of agreement between the reference measurement and a second measurement for TRAP test were 126 +/- 284 (n = 25) for untransported and 181 +/- 316 (n = 25) for PTS transported samples. In the reference measurements, 48/50 (96%) of TRAP values were within the normal range. After PTS transport, 35/50 (70%) of TRAP measurements in the central laboratory were within the normal range (p < 0.001). Mean +/- SD for ASPI test was 175 +/- 137. Bias +/- 95% limit of agreement for ASPI test were 12 +/- 109 (n = 25) for untransported and 68 +/- 250 (n = 25) for PTS transported samples. In the reference measurements, 7/50 (14%) ASPI values were above the cut-off level and defined as reduced aspirin responsiveness. After PTS transport, only 1/50 (2%) of the patients showed reduced aspirin responsiveness in the central laboratory measurements (p = 0.031). In conclusion, PTS transport had a significant influence on platelet function testing by the Multiplate() analyzer. Significantly fewer test results indicated normal platelet function in TRAP test and reduced aspirin responsiveness in ASPI test after PTS transport. Therefore, clinical decisions regarding platelet function and aspirin responsiveness should not be based on blood specimens transported by a PTS system.