To determine if the central command signal associated with isometric exercise is mass-dependent, 20 subjects (nine male, 11 female; 23 +/- 1 years) performed four 5-min bouts of supine isometric exercise with a large (quadriceps; LEG) and small (forearm; ARM) muscle mass. For each extremity, one bout entailed maintaining a constant force (CF; 20% maximal voluntary contraction) and the other constant electromyographic activity (CE; approximately 20% MVC initially). Central command was assumed to increase with CF and remain unchanged with CE. Heart rate increased more with LEG than ARM (P<0.001) and, in LEG, was higher in CF than CE at min 5 (P<0.001). Mean arterial pressure was higher in LEG (P<0.001) by min 2 and 10 +/- 3 mmHg higher in LEG CF than LEG CE by min 5 (P<0.001). Ratings of perceived exertion were highest in LEG CF (P<0.001); LEG CE did not differ from ARM CE (P<0.001) by min 4. The ARM responses did not differ between CF and CE in any variable. These data suggest that muscle mass influences the central command signal during isometric exercise and central command modulates this response in larger muscle masses.

Background: Orthotopic heart transplantation (HTx) is the gold standard treatment for patients with terminal heart failure. As donor organs are limited, patients are often on ventricular assist device (VAD) support before receiving HTx. We aimed to compare the outcome after HTx in patients with and without preoperative VADs as well as in patients who underwent different VAD implantation techniques.Methods: A total of 126 patients underwent HTx at our department between 2010 and 2019 and were retrospectively analyzed. While 47 patients underwent primary transplantation (No VAD), 79 were on VAD support. The preoperative and intraoperative parameters were comparable between the two groups.Results: VAD support significantly increased the HTx operation time (<0.0001), cardiopulmonary bypass time (P < .01), and warm ischemia time (P = .04). The ventilation time (P = .02), intensive care unit (ICU) stay (P = .01), and hospital stay (P = .02) were also significantly longer in VAD patients than in No VAD patients.Minimally invasive VAD implantation significantly reduced the requirement for perioperative blood transfusion (P = .01) and rethoracotomy (P = .01). Nonetheless, survival analyses did not show significant differences between the groups, but there was a trend of better results for the primary transplantation patients (30-day survival: No VAD = 91.1%, VAD = 86.1%; n.s.). Conclusions:We observed significantly worse perioperative parameters in patients who underwent transplantation after the implantation of a VAD compared to those who underwent primary transplantation. Minimally invasive VAD implantation without full sternotomy decreased complications during the subsequent HTx. In patients who are dependent on temporary VAD support as a bridge to transplantation, we believe that minimally invasive implantation should be performed if possible. K E Y W O R D Sheart transplantation, ventricular assist device

Background Primary graft dysfunction (PGD) is a common cause of early death after heart transplantation (htx). The use of extracorporeal life support (ECLS) after htx has increased during the last years. It is still discussed controversially whether peripheral cannulation is favorable compared to central cannulation. We aimed to compare both cannulation techniques. Methods Ninety patients underwent htx in our department between 2010 and 2017. Twenty-five patients were treated with ECLS due to PGD (10 central extracorporeal membrane oxygenator [cECMO] and 15 peripheral extracorporeal membrane oxygenator [pECMO] cannulation). Pre- and intraoperative parameters were comparable between both groups. Results Thirty-day mortality was comparable between the ECLS-groups (cECMO: 30%; pECMO: 40%, p = 0.691). Survival at 1 year (n = 18) was 40 and 30.8% for cECMO and pECMO, respectively. The incidence of postoperative renal failure, stroke, limb ischemia, and infection was comparable between both groups. We also did not find significant differences in duration of mechanical ventilation, intensive care unit stay, or in-hospital stay. The incidence of bleeding complications was also similar (cECMO: 60%; pECMO: 67%). Potential differences in support duration in pECMO group (10.4 ± 9.3 vs. 5.7 ± 4.7 days, p = 0.110) did not reach statistical significance. Conclusions In patients supported for PGD, peripheral and central cannulation strategies are safe and feasible for prolonged venoarterial ECMO support. There was no increase in bleeding after central implantation. With regard to the potential complications of a pECMO, we think that aortic cannulation with tunneling of the cannula and closure of the chest could be a good option in patients with PGD after htx.

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Background Heart transplantation (HTx) is the best therapy for end-stage heart failure. Unfortunately, death on the waiting list remains a problem. Decreasing the number of rejected organs could increase the donor pool. Methods A total of 144 patients underwent HTx at our department between 2010 and 2019. Of them, 27 patients received organs of donors with cardiopulmonary resuscitation (CPR) prior to organ donation (donor CPR) and were compared with patients who received organs without CPR (control; n = 117). Results We did not observe any disadvantage in the outcome of the donor CPR group compared with the control group. Postoperative morbidity and 1-year survival (control: 72%; donor CPR: 82%; p = 0.35) did not show any differences. We found no impact of the CPR time as well as the duration between CPR and organ donation, but we found an improved survival rate for donors suffering from anoxic brain injury compared with cerebral injury (p = 0.04). Conclusions Donor organs should not be rejected for HTx due to resuscitation prior to donation. The need for CPR does not affect the graft function after HTx in both short- and mid-term outcomes. We encourage the use of these organs to increase the donor pool and preserve good results.

Background The number of patients waiting for heart transplantation (HTx) is exceeding the number of actual transplants. Subsequently, waiting times are increasing. One possible solution may be an increased acceptance of organs after rescue allocation. These organs had been rejected by at least three consecutive transplant centers due to medical reasons. Methods Between October 2010 and July 2019, a total of 139 patients underwent HTx in our department. Seventy (50.4%) of the 139 patients were transplanted with high urgency (HU) status and regular allocation (HU group); the remaining received organs without HU listing after rescue allocation (elective group, n = 69). Results Donor parameters were comparable between the groups. Thirty-day mortality was comparable between HU patients (11.4%) and rescue allocation (12.1%). Primary graft dysfunction with extracorporeal life support occurred in 26.9% of the elective group with rescue allocated organs, which was not inferior to the regular allocated organs (HU group: 35.7%). No significant differences were observed regarding the incidence of common perioperative complications as well as morbidity and mortality during 1-year follow-up. Conclusions Our data support the use of hearts after rescue allocation for elective transplantation of patients without HU status. We could show that patients with rescue allocated organs showed no significant disadvantages in the early perioperative morbidity and mortality as well at 1-year follow-up.

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