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Reduced Postoperative Transfusion
Requirement After Beating-Heart Operations

Schiro, Gustavo; Ruiz, Roberto; Garberi, Javier;
Farias, Rubén; Alvarado, Julio; Giunta, Mario

Sanatorio La Entrerriana, Paraná, Entre Ríos, Argentina

RESUMEN

SUMMARY
Introduction: Coronary artery bypass grafting (CABG) on the beating heart through median sternotomy is a relatively new treatment, which allows multiple revascularization without the use of cardiopulmonary bypass (CPB).
Objective: To investigate the effect of coronary bypass with or without CPB on transfusion requirement.
Material and Methods: A retrospective review of 76 patients undergoing coronary artery bypass between January 1999, and March 2001, was done. The total population was divided into two groups: group A (n=38) with CPB and group B (n=38) without CPB. We analyzed requirement of whole blood units (WBU), packed blood red cells (PBRC), fresh frozen plasma (FFP), platelets (P), cryoprecipitate (CRYO-PPT) and transfusion-related cost.
There was no difference between the groups with respect to preoperative patient variables.
Results: Table 1

Nineteen patients in the group B (50 %) required no blood transfusion compared with only 1 (2.63 %) in the group A. Mean transfusion cost per patient was higher in the group A ($407.89 ± $334.81 vs. $100.00 ± $131.52, P < 0.05).
Discussion: The systemic inflammatory response has been attributed to cardiopulmonary bypass, with an increased morbidity risk that is potentially avoided by off-pump CABG. This systemic inflammatory response begins with the activation of complement, both coagulation pathways, and the fibrinolytic and kallikrein cascades. This complex set of interactions can have serious sequelae and have prompted physicians to seek improved patient management alternatives through less invasive procedures.
Conclusions: Coronary artery bypass grafting on the beating heart is associated with a significant reduction in postoperative transfusion requirement, and transfusion-related cost when compared with conventional revascularization with cardiopulmonary bypass and cardioplegic arrest.

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INTRODUCTION
   Morbidity and mortality after cardiopulmonary bypass (CPB) has been significantly decreased. However, the duration of CPB and its influence on hemostasis, platelet count, and function still contributes to postoperative bleeding.
There is still an important risk related to the transfusion of blood and blood products, such as the transmission of viral infections, the induction of immunology transfusion reactions, and suppression of the immune system.

   Coronary artery bypass grafting (CABG) on the beating heart through median sternotomy is a relatively new treatment, which allows multiple revascularization without the use of cardiopulmonary bypass (CPB) and this may reduce postoperative blood loss, the need for blood transfusion, and costs.

   The present study compared transfusion requirement in patients undergoing CABG either on the beating heart or with CPB and cardioplegic arrest.

OBJECTIVE
   To investigate the effect of coronary bypass with or without CPB on transfusion requirement.

MATERIAL AND METHODS
   A retrospective review of 76 patients undergoing coronary artery bypass between January 1999, and March 2001, was done. The total population was divided into two groups: group A (n=38) with CPB and group B (n=38) without CPB. We analyzed requirement of whole blood units (WBU), packed blood red cells (PBRC), fresh frozen plasma (FFP), platelets (P), cryoprecipitate (CRYO-PPT) and transfusion-related cost. (Figure 1)

Figure 1

    Anesthetic technique was standardized for all patients and the lungs were ventilated to normocapnia.

   In the on-pump group heparin was given at a dose of 300 IU/kg to achieve a target activated clotting time (ACT) of 480 seconds or above before commencement of CPB. In the off-pump group, heparin (100 IU/kg) was administered before the start of the first anastomosis to achieve an ACT of 250 to 350 seconds.

   OPCAB was performed through a sternotomy incision. Conduits for CABG including the left internal Mammary artery, radial artery, and saphenous vein were harvested in the standard fashion. Deep pericardial traction sutures were placed to facilitate elevation of the apex of the heart and exposure of the lateral wall of the myocardium. The right pleural space was opened when required to allow displacement of the heart to facilitate exposure of the circumflex coronary vessels. Revascularization of the left anterior descending coronary with the left internal mammary artery was typically performed first, followed by revascularization of the right coronary artery and the circumflex coronary artery distributions. After completion of the distal anastomoses, the proximal anastomoses were performed with the assistance of a partial occlusion aortic clamp. An intracoronary shunt was used only in case of relative electrocardiographic or hemodynamic instability or with excessive bleeding during the construction of the distal anastomoses.

   Stabilization of the coronary arteries was accomplished using a Octopus ® 2 stabilization system. CABG with CPB was performed through a sternotomy incision. Conduits for CABG including the left internal mammary artery, radial artery, and saphenous vein were harvested in the standard fashion. CPB was established by cannulating the ascending aorta and the right atrium. Nonpulsatile flow was used. Systemic temperature was kept between 34°C and 36°C. Myocardial protection was achieved by using intermittent antegrade hyperkalemic cold blood cardioplegia.
After surgery, both groups of patients were admitted to the ICU. The patients were extubated as soon as clinically indicated. An early extubation protocol was employed for both groups of patients. The patients were transferred from the ICU and discharged to home when clinically indicated by the attending surgeon.

   In the on-pump group the extracorporeal circuit was primed with 1000 mL of Hartmann solution, 500 mL of colloidal plasma volume substitute, 0.5 g/kg mannitol, and 6000 IU of heparin. During CPB, when additional volume was required, this consisted of colloidal plasma volume substitute (hematocrit level, >22%) or red blood cells (hematocrit level < 22%). In the off-pump group, intraoperative fluid administration was used together with inotropic support to maintain the mean systemic pressure at 60 mm Hg or greater.

   Fluid management postoperatively consisted in both groups of 5% dextrose, with additional colloidal plasma volume substitute or blood to maintain normovolemia and the hematocrit level at greater than 27%.

   On arrival in the intensive care unit (ICU), all patients underwent a routine coagulation profile, and full blood count. Derangements of the coagulation profile were treated by with a specific diagnosis-directed therapy. A platelet count of less than 70,000/µL was an indication for platelet transfusion. A hematocrit level of less than 24% was corrected by transfusion of red blood cells. Indications for reopening were a blood loss of greater than 500 mL over the first hour, greater than 300 mL for 2 consecutive hours, greater than 200 mL for 3 consecutive hours, or greater than 1 L over the first 8 hours.

   The total (intraoperative and postoperative) number of units of whole blood units, packed blood red cells, fresh frozen plasma, platelets and cryoprecipitate were recorded for each patient, and cost was calculated from the number of units transfused only.

   The numbers of transfused units received by each patient and transfusion-related costs are presented as means ± SEM. Comparison between the groups was performed by using the unpaired t test.

   The groups were similar in terms of age, body surface area, sex ratio, diabetes mellitus, extent of coronary disease, left ventricular function and graft distribution

RESULTS
Table 1.
Figure 2

Figure 2

   Nineteen patients in the group B (50 %) required no blood transfusion compared with only 1 (2.63 %) in the group A. (Figure 3) (Figure 4) Mean transfusion cost per patient was higher in the group A ($407.89 ± $334.81 vs. $100.00 ± $131.52, P < 0.05).

Figure 3

Figure 4

DISCUSSION
   The systemic inflammatory response has been attributed to cardiopulmonary bypass, with an increased morbidity risk that is potentially avoided by off-pump CABG. This systemic inflammatory response begins with the activation of complement, both coagulation pathways, and the fibrinolytic and kallikrein cascades. This complex set of interactions can have serious sequelae and have prompted physicians to seek improved patient management alternatives through less invasive procedures.

   The contact activation with the extracorporeal circuit, shear forces, activation of the complement system, fibrinolysis, and extrinsic factors, such as medications, all contribute to platelet dysfunction, which may result in increased postoperative bleeding. The need to decrease the incidence of postoperative bleeding and related complications has led to the development of strategies, such as the use of cell salvage devices to recirculate nonheparinized blood and the routine use in some instances of drugs, such as aprotinin or tranexamic acid.

   Recently, there has been a suggestion that by performing coronary revascularization on the beating heart, there may be a reduction of blood loss.

   This study shows a significant decrease in transfusion requirement with beating-heart operations when compared with conventional CABG with CPB.

   The explanation for the reduced postoperative blood loss observed in the off-pump group is certainly multifactorial. Thrombocytopenia and its relation to postoperative bleeding are well documented in association with CPB. Holloway and colleagues found that the decrease in platelet count during CPB was in excess of that accounted for by hemodilution for priming the extracorporeal circuit.

  The greater reduction of platelet counts observed in conventional CABG with CPB suggests a depletion caused by contact activation with extracorporeal surfaces, oxygenator, cardiotomy suction, and filters. However, the decrease of platelet counts was rarely less than the value (50,000-100,000/µL) normally required for hemostasis, suggesting a degree of impaired platelet function. Platelet dysfunction with the loss of aggregability is largely reported as a cause of bleeding after CPB.The current era of health care has placed higher emphasis on curtailment of costs and resources while maintaining quality of care and patient satisfaction. As such, the reduction of cost related to less transfusion requirement observed in the off-pump group may clearly compare with other reported strategies of cost containment, while avoiding the detrimental effect of CPB. In conclusion, this study shows that beating-heart coronary operations are associated with a significant reduction in transfusion requirement when compared with conventional operation with CPB and cardioplegic arrest. The routine implementation of the off-pump coronary operation should have significant implications in terms of reducing cost and postoperative complications related to blood-product transfusion.

CONCLUSIONS
   Coronary artery bypass grafting on the beating heart is associated with a significant reduction in postoperative transfusion requirement, and transfusion-related cost when compared with conventional revascularization with cardiopulmonary bypass and cardioplegic arrest.

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Reducción de los Requerimientos Transfusionales en Cirugía a Corazón Latiendo

RESUMEN
Introducción: La cirugía a corazón latiendo a través de esternotomía mediana, es una técnica relativamente nueva, que permite realizar revascularización múltiple sin utilizar circulación extracorpórea (CEC).
Objetivo: Evaluar los efectos de la cirugía de revascularización miocárdica (CRM) con y sin CEC sobre los requerimientos transfusionales.
Material y Métodos: Se evaluaron retrospectivamente 76 CRM realizadas entre enero de 1999 y marzo de 2001. Se dividió a las cirugías en dos grupos (G), con CEC (GA) o sin CEC (G B). Se analizaron los requerimientos en unidades de sangre total (ST), glóbulos rojos (GR), plasma (PF), plaquetas (PT) y crióprecipitados (CR), y los costos relacionados. No existieron diferencias entre los dos G respecto a las características preoperatorias de los pacientes (P).
Resultados: Tabla 1

Diecinueve P del grupo B (50 %) no requirieron ninguna transfusión en comparación con solo un P (2.63 %) del grupo A. El costo promedio por P fue mayor en el grupo A (407.89 ± 334.81 $ vs. 100.00 ± 131.52 $ p<0.05).
Discusión: A la CEC le ha sido atribuida la respuesta inflamatoria sistémica (RIS), con un incremento de la morbilidad que puede ser evitada sin CEC. Esta RIS comienza con la activación del complemento, ambas vías de la coagulación, y las cascadas de la fibrinolisis y la calicreina. Estas complejas interacciones pueden traer serias secuelas y han impulsado a los médicos a mejorar el manejo de los pacientes utilizando procedimientos menos invasivos.
Conclusión: La CRM a corazón latiendo se asocia con una significativa reducción de los requerimientos transfusionales y de los costos relacionados comparada con la cirugía con CEC.

 

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2nd Virtual Congress of Cardiology

Dr. Florencio Garófalo
Steering Committee
President
Dr. Raúl Bretal
Scientific Committee
President
Dr. Armando Pacher
Technical Committee - CETIFAC
President
fgaro@fac.org.ar
fgaro@satlink.com
rbretal@fac.org.ar
rbretal@netverk.com.ar
apacher@fac.org.ar
apacher@satlink.com

Copyright© 1999-2001 Argentine Federation of Cardiology
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