A simple clinical model for planning transfusion quantities in heart surgery.

BACKGROUND: Patients undergoing heart surgery continue to be the largest demand on blood transfusions. The need for transfusion is based on the risk of complications due to poor cell oxygenation, however large transfusions are associated with increased morbidity and risk of mortality in heart surgery patients. The aim of this study was to identify preoperative and intraoperative risk factors for transfusion and create a reliable model for planning transfusion quantities in heart surgery procedures. METHODS: We performed an observational study on 3315 consecutive patients who underwent cardiac surgery between January 2000 and December 2007. To estimate the number of packs of red blood cells (PRBC) transfused during heart surgery, we developed a multivariate regression model with discrete coefficients by selecting dummy variables as regressors in a stepwise manner. Model performance was assessed statistically by splitting cases into training and testing sets of the same size, and clinically by investigating the clinical course details of about one quarter of the patients in whom the difference between model estimates and actual number of PRBC transfused was higher than the root mean squared error. RESULTS: Ten preoperative and intraoperative dichotomous variables were entered in the model. Approximating the regression coefficients to the nearest half unit, each dummy regressor equal to one gave a number of half PRBC. The model assigned 4 units for kidney failure requiring preoperative dialysis, 2.5 units for cardiogenic shock, 2 units for minimum hematocrit at cardiopulmonary bypass less than or equal to 20%, 1.5 units for emergency operation, 1 unit for preoperative hematocrit less than or equal to 40%, cardiopulmonary bypass time greater than 130 minutes and type of surgery different from isolated artery bypass grafting, and 0.5 units for urgent operation, age over 70 years and systemic arterial hypertension. CONCLUSIONS: The regression model proved reliable for quantitative planning of number of PRBC in patients undergoing heart surgery. Besides enabling more rational resource allocation of costly blood-conservation strategies and blood bank resources, the results indicated a strong association between some essential postoperative variables and differences between the model estimate and the actual number of packs transfused.

Hemodynamic variations and pitfalls during venoarterial extracorporeal membrane oxygenation and left ventricular apical unloading as bridge to heart transplantation.

Despite the exponential increase in venoarterial extracorporeal membrane oxygenation (VA-ECMO) use during the past decade, adult cardiac ECMO is still accompanied by a high mortality rate. Moreover, although left ventricular distension is now a well-known drawback of VA-ECMO, there seems to be great variability in the hemodynamic management strategies and in the results reported among the various centers. Hemodynamic management of VA-ECMO can be even more challenging when complex configurations are deployed. Here we present and discuss an interesting case of a modified VA-ECMO that although it occurred a few years ago it is instructive for its hemodynamic implications and pitfalls. VA-ECMO can either save the patient or catalyze the deterioration of a compromised clinical condition and thus a close multiparametric monitoring is mandatory especially with complex ECMO arrangements. A thorough understanding of the hemodynamic changes and problems that may occur during these cases is necessary too. Ultimately, critical thinking along with a proactive approach for early referral to more specialized centers and immediate unloading of the left ventricle whenever it is deemed necessary, together may contribute to reduce the relatively high mortality rate with this type of support. .

Patient blood management in cardiac surgery: The "Granducato algorithm".

BACKGROUND: Patients undergoing cardiac surgery are subject to severe alterations of the coagulation system. The four cardiac surgery centers in Tuscany (Italy) structured and shared an algorithm (Granducato Patient Blood Management algorithm, G-PBMa) with predefined interventions for patient blood management. The aim of the study is to analyze the impact of that algorithm on the transfusion needs and bleeding-related outcomes in a large patient population. METHODS: Multicenter retrospective observational study on 3839 patients undergoing cardiac surgery at the four cardiac centers in Tuscany. The G-PBMa was released at the end of 2015 and it was structured in three parts: pre-, intra-, and post-operative. The year 2014, before the G-PBMa (1955 patients) and the year 2016 (1884 patients) after the G-PBMa in place were compared. Logistic regression analyses were used. RESULTS: The main changes introduced were the routine application of viscoelastic tests in bleeding patients (+72%) and the use of fibrinogen and prothrombin complex concentrate (+67%). The G-PBMa resulted in a significant reduction in the overall transfusion rate and in the transfusion rate of the separate blood products (relative risk for transfusions: 0.75, 95% confidence interval 0.65-0.85, P = 0.001). For preoperative hemoglobin values of between 8 and 10 g/dL, the absolute difference in RBC transfusion rate before and after the G-PBMa introduction ranged around 15%-17%. The G-PBMa introduction determined lower (P = 0.02) chest drain blood loss, lower (P = 0.001) postoperative acute kidney injury and shorter (P = 0.001) hospital stay. CONCLUSIONS: The G-PBMa was effective in reducing blood loss, transfusion requirements, and resulted in a better outcome.

Reduction of hyperacute rejection and protection of metabolism and function in hearts of human decay accelerating factor (hDAF)-expressing pigs.

OBJECTIVE: The use of pig hearts can solve the problem of shortage of donor hearts for transplantation. However, targeting rejection by single genetic modification was proven to be ineffective, highlighting the requirement for complex genetic modifications and more effective methods for transgenic animal production. We evaluated here whether hearts of hDAF transgenic pigs generated using our technique sperm-mediated gene transfer (SMGT) will be protected from structural damage, metabolic changes, and mechanical dysfunction during perfusion with human blood. METHODS: Hearts from control (C, n = 6) or transgenic (T, n = 5) pigs were perfused ex vivo for 4 h with fresh human blood using the ex vivo working mode system allowing monitoring of the function, metabolism, and structure. RESULTS: Cardiac output (mean+/-SEM) was maintained in T constant throughout the experiment, at 3.58+/-0.36 and 3.83+/-0.14 l/min after 30 min and 4 h, respectively, while cardiac output decreased to 1.95+/-0.35 l/min in C after 30 min of perfusion (p < 0.01 vs. T). The maximum increase in coronary perfusion pressure was reduced in T to 154+/-16% as compared to C (237+/-10%, p < 0.001). Myocardial ATP after 4 h was 21.1+/-1.1 nmol/mg dry wt (similar to initial) in T, while it decreased in C to 17.2+/-1.4 (p < 0.05). Deposition of complement factors C3 and C5b9 was present in C but not in T after perfusion. CONCLUSION: We have shown that hearts from hDAF transgenic pigs produced by SMGT are protected during perfusion with human blood and are metabolically stable and maintain mechanical function above the threshold level for life support.

Carbon monoxide improves cardiac energetics and safeguards the heart during reperfusion after cardiopulmonary bypass in pigs.

Ischemia-reperfusion injury, a clinical problem during cardiac surgery, involves worsened adenosine trisphosphate (ATP) generation and damage to the heart. We studied carbon monoxide (CO) pretreatment, proven valuable in rodents but not previously tested in large animals, for its effects on pig hearts subjected to cardiopulmonary bypass with cardioplegic arrest. Hearts of CO-treated pigs showed significantly higher ATP and phosphocreatine levels, less interstitial edema, and apoptosis of cardiomyocytes and required fewer defibrillations after bypass. We conclude that treatment with CO improves the energy status, prevents edema formation and apoptosis, and facilitates recovery in a clinically relevant model of cardiopulmonary bypass surgery.