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/m(2) 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, ß-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.

Complementary and Alternative Medicine in Cardiac Surgery: Prevalence and Modality of use.

BACKGROUND: Complementary and alternative medicines are developing at a growing rate but their use in the hospital setting is little known, ignoring risk or benefit in practice. The objectives of the study were to quantify the prevalence of complementary and alternative medicines used by patients admitted to a cardiac surgery department. METHODS: Patients and staff at the Cardiac Surgery unit of Angers University Hospital (France) were surveyed regarding their modality of complementary and alternative medicines use, between April 01, 2013, and April 18, 2014, by means of an anonymous questionnaire. RESULTS: Of 154 patients included in the study, 58% used a complementary and alternative medicine at least once in their lifetime, 38% during the preceding year, and 14% between the consultation and surgery. In all, 71% used them as a complement to their conventional medical treatment. Of those who used a complementary and alternative medicine during the year of their surgery procedure, only 29% informed their physicians and paramedical staff about it. CONCLUSIONS: Complementary and alternative medicines use among patients admitted to cardiac surgery units is common. Yet there is a real lack of knowledge regarding these health practices among physicians and paramedical staff.

Early postoperative undernutrition following aortic valve replacement surgery.

BACKGROUND: Experiencing loss of appetite after cardiac surgery is often noted during daily care and has been described by several studies. However, no information is available on either energy needs or spontaneous food intake following aortic valve replacement surgery. The goal of this study was to assess the risk of early postoperative undernutrition following aortic valve replacement in a group of patients who were preoperatively well-nourished. METHODS: Anthropometrics data (body mass index, fat free mass index, albuminemia and prealbuminemia, extracellular water), energy balance and appetite were assessed in a cross-over prospective observational study. . Each subject was enrolled in two procedures: surgery and routine coronary angiograms which were used for control matched assessment. Data were assessed during the pre-procedure period (d-15 to d-1) and the post-procedure period (d0 to d+4). Energy expenditure was determined by indirect calorimetry. RESULTS: 15 patients median aged 73 years old [65-77] were included in the study. In post-surgery period, weight and extracellular water were increased and correlated (r2 = 0.571, p = 0.003). CRP was increased from 2 [2;3] to 91 [73;138] (p = 0.001). Ingested calories decreased from 1451 [1272-1640] kcal to 372 [22-528] kcal (p = 0.001) while energy expenditure was increased from 1358 [1180-1559] kcal to 1613 [1472-1670] kcal (p = 0.002). A severe loss of appetite was noted (p = 0.011). None of these changes were observed in the control phase. CONCLUSION: Energy balance was strongly negative after cardiac surgery. Cardiac surgery increased endogenous metabolism by 20% and a severe loss of appetite decrease food intake by 75%, which does not make it possible to compensate for the increase in resting energy expenditure.

Haemodynamic performance of the small supra-annular Trifecta bioprosthesis: results from a French multicentre study.

OBJECTIVES: The St Jude Medical Trifecta bioprosthesis incorporates a single pericardial sheet externally mounted on a titanium stent that provides excellent haemodynamic results. The purpose of this multicentre study was to report on the haemodynamic performance and the expected lower risk of prosthesis-patient mismatch in patient with small aortic annulus diameters. METHODS: The 19- and 21-mm Trifecta valves were implanted in 88 and 266 eligible patients, respectively between 2011 and 2013 at three centres in France (Angers, Rennes and Amiens). The mean age of the population was 78 ± 7 and 76 ± 6 years for 19- and 21-mm valve sizes of which 96.6 and 68% were female, respectively. The aortic valve replacement was associated with another surgery in 18.2 and 21.8% in each group, respectively. RESULTS: The mean follow-up was 20.3 ± 11.9 and 24 ± 11.4 months for 19- and 21-mm valves, respectively. Early all-cause mortality was 2.5% and late mortality occurred in 5.8% of patients. The mean pressure gradient and the effective orifice area at discharge and at 1 year were respectively 12.4 ± 4.6 and 14.7 ± 5.8 mmHg (P = 0.003), 1.5 ± 0.3 and 1.4 ± 0.9 cm(2) (P = 0.06) in the 19-mm valve group; 10.4 ± 3.8 and 11.7 ± 4.5 mmHg (P = 0.001), 1.8 ± 0.3 and 1.5 ± 0.4 cm(2) (P = 0.1) in the 21-mm valve group. At 1 year, only 38 (11%) and 28 (8.1%) patients presented a moderate or severe prosthesis-patient mismatch for the two groups. After univariate analysis, no risk factor of mismatch was found. CONCLUSIONS: The 19- and 21-mm St Jude Medical Trifecta provide excellent haemodynamic performance and the rate of moderate and severe prosthesis-patient mismatch is low.

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.