Introduction: The haematopoietic growth factors erythropoietin (EPO) and thrombopoietin (TPO) are main regulators of erythro- and thrombopoiesis. Cell loss caused by operative procedures may alter serum levels of the hormones, resulting in well known phenomenons like reactive thrombocytosis.

Material and Methods: Blood samples from 12 patients (mean age 62  8 years) were obtained before and on days 1, 5 and 10 after CABG. sEPO and sTPO levels were determined by commercially available ELISA-Kits (R&D Systems, Germany). In addition, platelet count (PC) and hemoglobin concentration (Hb) were determined.

Results: Prior to CABG, sEPO (14.6  9.1 mU/ml), sTPO (172.3  67.0 pg/ml), PC (248.0  119.5/nl) and Hb (9.4  1 mmol/l) were within a normal range. At day 1 after surgery, Hb and PC were significantly decreased to 6.9  0.8 mmol/l and 143.8  95.6/nl. In contrast, sEPO and sTPO were significantly elevated to 36.0  25.6 mU/ml and 378.9  112.6 pg/ml, respectively, in spite of hemodilution. In particular, sTPO elevation was followed by a significant increase in PC (357  178.6/nl) at day 10 after surgery compared to preoperative values.

Conclusions: Appropriate to the decrease in hemoglobin concentration and platelet count, clear alterations of serum erythropoietin and thrombopoietin levels could postoperatively be observed. Whereas hemoglobin concentration returned nearly in a normal range at day 10 after surgery, the alterations of the hormones resulted in the phenomenon of reactive thrombocytosis.

Introduction

Ex situ machine perfusion (ESMP) is an emerging technology for cardiac allograft maintenance. However, ESMP of donor hearts is still under development and requires optimization for specific donor subpopulations, such as donors with circulatory death, donors with advanced age, and donations with distant procurement. Thus, respective research projects in basic science are needed. Nevertheless, large animal models are expensive, require more personnel and fewer genetically modified strains are available. Thus, we modified a commercially available non-miniaturized experimental rodent heart perfusion apparatus into a clinically comparable and relevant miniaturized ex-situ heart perfusion system.

Methods

A commercially available rodent heart perfusion apparatus was used as a basis. The apparatus was modified with commercially available and self-constructed components and tubing according to the human ESMP system. The hearts were procured from male and female Lewis rats (N=40). Equivalently to the clinical procedure, the system was primed with the heparinized blood of the organ donor animal instead of physiologic buffer solutions. After cannulation of the ascending aorta, the hearts were perfused in an anterograde fashion and in a pressure-controlled mode.

Results

Our ESMP system consisted of a micro-centrifugal pump, a heat exchanger, a hollow fiber membrane micro-oxygenator, and a myocardial microcirculation monitoring system. The total priming volume of the system was 14 ml. No additional blood from another animal was needed. All hearts were maintained for one hour. Pacing was performed when required. After maintenance perfusion, we evaluated the ventricular contractility of the hearts in an ejecting-working mode.

Conclusion

Clinically relevant research questions can be investigated and answered in a rodent model of ex-situ donor heart perfusion while exactly mimicking the clinical procedure.

Introduction

Extracorporeal membrane oxygenation (ECMO) is increasingly used for circulatory or pulmonary support not only in-hospital but also out-of-hospital. Small dimensions and a lightweight design are important, especially for out-of-hospital use but also for intra-hospital transportation of patients who require ECMO support. We share our first experience with the new Colibrì ECMO system.

Methods

From December 2022 to January 2023, we used the new Colibrì ECC system in six patients with cardiac or pulmonary failure.

Results

The Colibrì system was used in-hospital in six patients with post-cardiac surgery low output syndrome, respiratory failure due to influenza or acute respiratory distress syndrome, cardiogenic shock, pulmonary embolism, and failed weaning from cardiopulmonary bypass. The system was implanted in venovenous (VV) and venoarterial (VA) fashion in 3 patients, respectively. One patient received left-ventricular unloading. The ECMO run time was up to 13 days. We did not notice any complications according to the extracorporeal circulation system. No ECMO system changes were required.

Conclusion

We conclude from this first case series that the new Colibrì system is safe and effective for in-hospital ECMO indications. The small dimensions and lightweight design are very beneficial for the transportation of patients. A use in out-of-hospital situations should be considered.