J.J. Corbeau

A combined approach for improving cardiopulmonary bypass in coronary artery surgery: a pilot study.

Background: This is a pilot study carried out to assess the feasibility and the clinical impact of a combined approach of cardiopulmonary bypass (CPB) with reduced anti-coagulation. Methods: We used a retrospective, non-randomized analysis of 45 consecutive patients undergoing coronary artery bypass using standard CPB with full anticoagulation (activated clotting time, ACT, > 450 s) (Group 1; n = 23) or closed, heparin-coated CPB with low anticoagulation (ACT> 250 s), precise heparin and protamine titration, controlled suction, and retrograde autologous prime (Group 2; n = 22). Results: Patients were similar except for a higher incidence of three-vessel disease in Group 2 (77.3% versus 47.8%; p < 0.03). Heparin was reduced by 41% in Group 2 and protamine by 56% ( p < 0.0001). Total postoperative blood loss was similar between Groups 1 and 2 (429 ± 149 versus 435 ± 168 ml, respectively). However, the operative hematocrit decrease was lower in Group 2 (-1.6± 7.5% versus -6.9± 4.8%; p = 0.007), although hemodilution was similar, as reflected by the blood protein level. The need for postoperative inotropic support was less frequent in Group 2 (36.4% versus 65.2%; p = 0.05). Within the subgroup of patients weaned from CPB without requiring inotropic support ( n = 35), the cardiac index dropped significantly in Group 1 ( p = 0.003) 6 h after the start of CPB, whereas it remained stable in Group 2 ( p = 0.92). Using multivariate analyses, Group 2 was found to be more protected than Group 1 against myocardial cellular injury ( p = 0.046) and need for postoperative inotropic support ( p = 0.014). Conclusion: The pejorative postoperative outcome in coronary artery surgery was attenuated through a combined approach aimed at improving CPB.

Increasing mean arterial pressure during cardiac surgery does not reduce the rate of postoperative acute kidney injury.

Introduction: We hypothesized that the optimization of renal haemodynamics by maintaining a high level of mean arterial blood pressure (MAP) during cardiopulmonary bypass (CPB) could reduce the rate of acute kidney injury (AKI) in high-risk patients. Methods: In this randomized, controlled study, we enrolled 300 patients scheduled for elective cardiac surgery under cardiopulmonary bypass. All had known risk factors of AKI: serum creatinine clearance between 30 and 60 ml/min for 1.73m2 or two factors among the following: age >60 years, diabetes mellitus, diffuse atherosclerosis. After a standardized fluid loading, the MAP was maintained between 75-85 mmHg during CPB with norepinephrine (High Pressure, n=147) versus 50-60 mmHg in the Control (n=145). AKI was defined by a 30% increased of serum creatinine (sCr). We further tested others definitions for AKI: RIFLE classification, 50% rise of sCr and the need for haemodialysis. Results: The pressure endpoints were achieved in both the High Pressure (79 ± 6 mmHg) and the Control groups (60 ± 6 mmHg; p<0.001). The rate of AKI did not differ by group (17% vs. 17%; p=1), whatever the criteria used for AKI. The length of stay in hospital (9.5 days [7.9-11.2] vs. 8.2 [7.1-9.4]) and the rate of death at day 28 (2.1% vs. 3.4%) and at six months (3.4% vs. 4.8%) did not differ between the groups. Conclusion: Maintaining a high level of MAP (on average) during normothermic CPB does not reduce the risk of postoperative AKI. It does not alter the length of hospital stay or the mortality rate.

Iloprost (Ilomédine ®) et circulation extracorporelle avec héparinisation conventionnelle chez un patient ayant une thrombopénie à l'héparine

A 73-year-old female patient was admitted for myocardial infarction. Conventional treatment with heparin was started, intraaortic balloon assistance was required for several days, together with heparin. The platelet counts decreased progressively, from 288 G · 1−1 on admission to 41 G · 1−1 on the 16th day, despite the use of low molecular weight heparin. The in vitro heparin platelet aggregation test remained positive. This aggregation ended on adding iloprost, an analogue of prostacyclin, to the platelet culture bath. A coronary aortic bypass graft was required. An infusion of iloprost was started just after induction of anaesthesia. The initial dose of 0.5 ng · kg−1 · min−1 was gradually increased to 20 ng · kg−1 · min−1. Heparin (400 IU · kg−1) was thereafter added. To maintain a mean blood pressure of a least 50 mmHg, an infusion of up to 10 μg · kg−1 · min−1 of phenylephrine was given. As it was insufficient, an infusion of up to 1 μg · kg−1 · min−1 noradrenaline was required. The iloprost infusion was gradually stopped 15 min before the end of CPB, together with that of noradrenaline. Platelet aggregation tests were positive after protamine had been given, whereas they had been negative during the infusion of iloprost. There was no abnormal postoperative bleeding. An infusion of 2 ng · kg−1 · min−1 was started at the sixth postoperative hour for 48 h, until the coumarin-like agent had started taking its effects. It is concluded that iloprost might be useful for carrying out cardiac surgery in patients with heparin-induced thrombocytopaenia.

CMR assessment after a transapical-transcatheter aortic valve implantation

AIMS To describe the time course of myocardial scarring after transapical-transcatheter aortic valve implantation (TA-TAVI) with the Edwards SAPIEN XT™ and the Edwards SAPIEN™ prosthesis in a 3-month follow-up study using cardiac magnetic resonance imaging (CMR). METHODS In 20 TA-TAVI patients, CMR was performed at discharge and 3 months (3M). Cine-MRI was used for left ventricular (LV) functional assessment, and late gadolinium enhancement (LGE) imaging was employed for detecting the presence of myocardial scarring. Special attention was given to any artifacts caused by the prosthesis, which were consequently defined using a three-grade artifact scale. RESULTS We systematically reported the presence of small LGE hyperintensity relating to the apical segment, with no variation found between discharge and 3M (2.8±1.6g vs. 2.35±1.1g). LV ejection fraction, end-diastolic, and end-systolic volumes did not significantly vary. A small area of apical akinesia was observed, with no improvement at follow-up. Whereas the Edwards SAPIEN XT™ prosthesis and the Edwards SAPIEN™ prosthesis are both constituted by metallic stenting structure, the Edwards SAPIEN™ was responsible for a larger signal void, thus potentially limiting the diagnostic performance of CMR. CONCLUSIONS CMR may be performed safely in the context of TA-TAVI. The presence of a very small apical infarction correlating with focal akinesia was observed. As expected, the Edwards SAPIEN XT™ prosthesis was shown to be particularly suitable for CMR assessment.

An ex vivo evaluation of blood coagulation and thromboresistance of two extracorporeal circuit coatings with reduced and full heparin dose

OBJECTIVES Bioactive Carmeda® heparin-coated extracorporeal circuits (ECCs) have been shown to reduce contact phase and coagulation activation during cardiopulmonary bypass (CPB). Heparin coating is therefore effective in safely reducing coagulation during routine CPB. Balance® Biosurface is a new, recently developed biopassive coating containing negatively charged sulphonated polymers. This study sought to compare the clotting activation and thromboresistance of the Balance® (B) circuit with that of the Carmeda® (C) with full-dose systemic heparin (FDH) and reduced-dose systemic heparin (RDH). METHODS This ex vivo study set-up comprising 40 experiments consisted of simplified ECC and circulation of freshly donated human blood. RDH and FDH regimens were obtained with 0.5 IU/ml and 1 IU/ml heparin administered to reach target activated clotting times (ACTs) of 250 and 500 s, respectively. The study design comprised four groups: FDH-C, FDH-B, RDH-C and RDH-B (all n = 10). Blood was sampled prior to and during the 2-h CPB. Coagulation activation was assessed (FXIIa, F1.2) and electron microscope scan imaging of oxygenators enabled determination of adhesion scores. RESULTS With a biopassive compared with bioactive surface, mean ACT was lower, regardless of the heparin regimen applied (P < 0.001), whereas the total heparin dose required to maintain ACT was above target level (P < 0.001). However, FXIIa and F1.2 values were similar in all groups throughout, as were pressure gradients among oxygenators. All groups demonstrated similar adhesion scores following ultrastructural oxygenator assessment. CONCLUSIONS In the absence of surgical-related haemostatic disturbances and based on target ACT levels under reduced- or full-dose heparin, the clotting process was similar to heparin-coated and new sulphonated polymer-coated ECC, both demonstrating similar thromboresistance.

Ex vivo simulation of cardiopulmonary bypass with human blood for hemocompatibility testing

Object: Experimental circuits for biomaterial surface testing are frequently limited by the tested blood volume, composition of the circuit, flow conditions and the use of animal blood. This report describes an ex vivo set-up for simulated cardiopulmonary bypass with human blood perfusion. We investigated the clinical generalizability of the observed effects on hematological and metabolic parameters and the hemocompatibility of the system. Methods: The simulated cardiopulmonary bypass circuit consisted of a heparin-coated tubing system connected to an oxygenator and a venous reservoir. Normothermic flow of blood obtained from healthy donors was maintained at 2.4 L/min/m2 by a roller pump. Heparin was dosed to obtain a target activated clotting time (ACT) ⩾500 s. Blood was drawn at baseline and 0, 10, 60 and 120 minutes following the initiation of blood flow to determine hematological and metabolic parameters and the hemocompatibility of the extracorporeal system. Data were analyzed using repeated measures ANOVA. Results: Two hours of blood perfusion resulted in a small, but clinically unimportant reduction in hematocrit, whereas hemoglobin levels and red blood cell, platelet and leukocyte counts remained stable. There was a significant increase in ACT throughout the experiment. While pO2 levels and the pH remained unaltered during the experiment, pCO2 values decreased from 51 ± 6 mmHg at T0 to 41 ± 3 mmHg at T120 (p<0.001). Simulated cardiopulmonary bypass induced a two-fold increase in C3a (p=0.001) while tissue factor was decreased from 44 ± 14 pg/mL at T0 to 38 ± 13 pg/mL at T120 (p=0.009). Levels of CD40L, prothrombin fragment 1+2, β-thromboglobulin and factor VIIa remained stable over time. Conclusion: The ex vivo set-up for simulated cardiopulmonary bypass mimicked the clinical cardiosurgical setting. Exposure of fresh donor blood to the extracorporeal circuit showed a good hemocompatibility, indicated by maintained hematological parameters and a mild immune response.

Increased cerebral blood flow velocities assessed by transcranial Doppler examination is associated with complement activation after cardiopulmonary bypass.

The role of complement activation on the cerebral vasculature after cardiopulmonary bypass (CPB) is unclear. The goal of the study was to assess whether heparin-coated CPB reduces complement activation, and influences cerebral blood flow velocities (CBFV). Twenty-four patients undergoing coronary surgery were randomly allocated to non-coated (NC-group) or heparin-coated (HC-group) CPB. Complement activation was assessed by measuring sC5b-9. Transcranial Doppler (TCD) was performed on middle cerebral arteries before and after CPB. Systolic (SV), diastolic (DV) and mean (MV) CBFV were measured. Significant increase of sC5b-9 (p=0.003) was observed in the NC-group and CBFV increased after CPB (SV by 27%, p=0.05; DV by 40%, p=0.06; MV by 33%, p=0.04) whereas no changes were detected in the HC-group. TCD values were higher in the NC-group than in the HC-group (SV, p=0.04; DV, p=0.03; MV, p=0.03) although cardiac index, systemic vascular resistance, haematocrit and pCO2 were similar. Postoperative SV, DV and MV were significantly correlated with sC5b-9 (r=0.583, p=0.009; r=0.581, p=0.009; r=0.598, p=0.007, respectively). Increased CBFV after CPB are correlated to the level of complement activation and may be controlled by heparin-coated circuits.

0179: Transcatheter valve-in-valve implantation in patients with failed aortic bioprosthesis: immediate and medium-term outcomes of 15 procedures

Background TAVI offers an attractive option for patients with failed bioprosthesis and high operative risk (valve-in-valve concept). Purpose The objective of this study was to analyze outcomes of patients with failed aortic bioprosthesis undergoing transcatheter aortic valve-in-valve implantation. Methods From January 2012 to January 2015, 15 patients with degenerated aortic valve bioprosthesis underwent transcatheter aortic valve-in-valve implantation in our institution. Mean patient age was 82±6 years. Mean logistic Euroscore was 36±16% and mean STS score was 16±14%. The mean follow-up was 260±316 days. Results The failing bioprosthesis were Cryolife O’brien in 5 patients, Carpentier Edwards in 5 patients, Medtronic mosaic in 4 patients and Mitroflow in 1 patient. Bioprosthesis mode of failure was stenosis (n=6), regurgitation (n=5), or combined stenosis and regurgitation (n=4). The mean degenerative time was 11.15±6.1 years. Implanted devices included Medtronic CoreValve (n=6) and Edwards SAPIEN (n=9). Successful implantation of a transcatheter aortic valve-in-valve with the patient leaving the catheterization laboratory alive was achieved in all patients. Adverse procedural outcomes included initial device malposition in 3 cases requiring a second valve, retroperitoneal hematoma in 1 patient, permanent pacemaker in 1 patient, Stroke in 1 patient and acute renal failure in 1 patient. The mean transvalvular gradient passed from 48.7±17.63 to 18.32±9.3mmHg in stenotic degenerated bioprosthesis. No significant aortic regurgitation was observed post-implantation. During hospitalization, 1 patient developed myocardial infarction. The medium inhospital stay was 13.4±7.7 days. During later follow-up, there was no death, no myocardial infarction and no stroke or TIA. 2 patients were hospitalized for heart failure. Conclusion Transcatheter aortic valve-in-valve implantation seems to be feasible and safe in both stenotic and regurgitant degenerative bioprosthesis.