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New Extracorporeal Vacuum-Assisted Device to Optimize
Cardiopulmonary By-pass:
preliminary result of multicentric study
Seanne AZZOLINA, MS ECCP*, Antonio PETRALIA, MS ECCP**,Andrea CAVALLUCCI, CCP**, Claudio COSTANTINI, MD***, Giuseppe SPEZIALE, MD***, Mauro LAMARRA, MD** *The Department of Cardiovascular Surgery Maria Beatrice Hospital, Firenze Italy **The Department of Cardiovascular Surgery Maria Cecilia Hospital, Cotignola (RA) Italy ***The Department of Cardiovascular Surgery Anthea Hospital, Bari Italy (Free introduction of the speaker regarding marketing survey of Mini invasive Extracorporeal circulation and generation of free haemoglobin caused by roller suction). The aim of the EVADO system is to optimize CPB through 4 steps: 1. The minimization of hemodilution on CPB which leads to the reduction of cell mediated pro-inflammatory effects, easy maintenance of hosmotic pressure and high HCT and Hb levels during CPB with decreased need for transfusions. 2. A true separation of blood from extra-cavitary suction. As we know, in traditional systems, suction and re-infused blood is a very powerful activator of post CPB inflammatory processes. In EVADO system, suction blood is truly separated and then processed through cell saver to be re-infused later. 3. The reduction of mechanical damage to red blood cells and inflammatory activation: EVADO system avoids the use of roller pumps (which are themselves a pro-inflammatory factor) for extra-cavitary suction, thus reducing blood cell damage. 4. An increased intra-operatory flexibility and surgical versatility: miniaturized CPB does not allow big amounts of air into circuits, thus limiting it’s use only to a specific kind of operations. EVADO, being an open system, is much more flexible and can be reliably and safely used in a wide range of cardiac operations. Let’s take a look at the EVADO system: it must be emphasized that EVADO is not to be considered a miniature CPB, but an integrated system, designed to optimize extracorporeal circulation. The system components are: - the ADMIRAL which is a phosforilcholine-coated oxygenator that requires low priming volumes (190 ml) has a limited (1,35 m2) contact surface and contains a venous reservoir (3200 ml, 80 micron filter) as well as an accessory independent cardiotomy reservoir (1800 ml, 40 micron filter) allowing separation of pericardial suction blood. - the HARMONY Smart Suction System which allows automatic auto-regulation of pumpless extra-cavitary blood suction, with rates and pressures depending on whether suction is required for blood/air surfaces (skimming) or fluids (pooled) - Vacuum Assisted Venous Drainage (VAVD) and pumpless intra-cavitary blood suction are managed by a digital vacuum regulator that is connected to the oxygenator reservoir. - retropriming can be performed - Paediatric circuits with 3/8 inch tubing for both arterial and venous lines. - no use of roller pumps for suction lines - all these components make the EVADO system! You can get a better idea of the system from this slide that compares conventional CPB and EVADO system. As you can see, roller pumps are not used for suction blood: intracavitary suction blood goes directly to the venous reservoir while extracavitary suction blood is sent to the independent cardiotomy reservoir. We prospectively randomized to either EVADO or conventional CPB 324 patients undergoing open chest surgery for a wide variety of cardiac conditions. Patients with severe renal or liver failure or presenting major clotting function problems were not deemed suitable for randomization. Similarly, patients undergoing emergency or re-do surgery, those requiring circulatory arrest or CPB times above 2 hours were not considered for the study. Of the 324 eligible patients,25 required blood transfusion prior or during surgery and 38 showed procalcitonin levels greater than 0,5 ng/mL. Since the measurement of haptoglobin, a major index of hemolysis, can be significantly affected by high procalcitonin plasma concentrations, this group of patients was excluded from the study. Therefore 121 patients were included in the conventional CPB group and 140 subjects were included in the EVADO group. The 2 groups were similar with regard to type of cardiac condition and intervention, EUROSCORE, NYHA and Canadian Class, as well as to age, body surface, preoperative HCT and Hb levels, mean CPB and aortic cross-clamp duration. In all patients with the EVADO system, surgery could be completed without the need to switch to conventional CPB. In both groups the ADMIRAL oxygenator was employed. For all operations we used the same arterial and venous cannulae (diameter was selected on the patient’s BSA) and neither cell savers, nor hemo-concentration or hemo-filtration devices were used. Priming solution was the same in all patients (1000 ml), however in the EVADO group retrograde bleeding of arterial and venous lines in a specific closed bag unit,allowed to limit the prime solution to approx 750 ml. Systemic anticoagulation was obtained by sodium heparine titrated to achieve values of 480 seconds before initiating CPB. All operations were performed by median sternotomy under moderate hypothermia (34C°) using anterograde or selective coronary blood cardioplegia with St.Thomas solution at a temperature of 4-8 C° All patients received TRANEXAMIC acid. HCT and Hb were measured on blood samples obtained before starting CPB as well as 5, 30 and 60 minutes thereafter. To asses the extent and the presence of hemolysis, free Hb and Haptaglobin plasma levels were also measured at the same time. Haptaglobin is a plasma glycoprotein that binds Free Hb and decreases during intra or extravascular hemolysis, but also in association with other pathological conditions such as bacterial infections. These, in turn, can be detected by elevated levels of procalcitonin. Consequently, patients with Procalcitonin levels exceeding 0,5 ng/ml, were not considered suitable for analysis. Blood loss, along with the total volume of transfused blood derivates (CRC, platelets and plasma) was measured hourly in the 12 hours after surgery, and daily afterwards. An arbitrary Hb level of 8 g/dL was used as a cut-off for transfusion. As I was saying before, both Free Hb and Haptaglobin plasma levels were recorded in the 2 groups 30 and 60 minutes after the onset of CPB. Values are expressed as percent change relative to the control values recorded at the beginning of CPB. In this slide you can see the behaviour of free Hb plasma levels, in the 2 groups, during CPB. The increase of FHb was significantly greater in the control group than in EVADO group. In fact, compared to the values recorded at the beginning of CPB, the percent of increase of this parameter after starting Extracorporeal Circulation was: 20,38 and 7,01 at 30 minutes and 31,61 and 17,21 at 60 minutes. The lesser degree of hemolysis occurring in the EVADO group was also indicated by the behaviour of Haptaglobin that, throughout CPB, was consistently and significantly lower in patients undergoing conventional CPB. Hb levels were recorded in the 2 groups during CPB and in the first 12 hours of ICU admission. Figures represent the difference, relative to the intra-operative value measured before starting CPB. Throughout the observation period, Hb concentrations recorded in patients of the EVADO group (solid blue line) are consistently, but not significantly, greater than in controls. Total (left) and hourly (right) blood loss were recorded in the 2 groups during the first 12 hours of ICU admission. The difference in patients of the EVADO group (solid blue line) is most obvious in the first and second post-operative hour when it reaches statistical significance. Overall, total bleeding was respectively 314,8 ml in the control group and 251,3 ml in the EVADO group. The need for Concentrated red blood cells was significantly lower in the EVADO group (orange bar) Time to extubation was respetively 10,0 and 8,7 hrs (not significant). ICU stay 42,4 and 36,6 hrs (not significant). No significant differences in hospital mortality and total duration of hospitalization were found. As a conclusion, we evaluated the potential advantages of the EVADO system and we experienced that it can be used in a great variety of cardiac operations and it’s application results in a lesser hemolysis, decreased blood loss and reduced need for blood transfusion, with a consequent better outcome for the patient.

Source: http://www.dideco.ru/Congress/Summary%20Presentation%20Congress%20.pdf