Effect of cardiopulmonary bypass on hemostasis in patients undergoing cardiac surgery

This study aimed to evaluate the hemostatic derangement in patients undergoing elective cardiac surgery using cardiopulmonary bypass. Total 55 patients of either sex, were divided into three groups: Group A (n=20): Patients selected for elective cardiac surgery without cardiopulmonary bypass; Group B (n=20): Patients who undergone cardiac surgery with cardiopulmonary bypass time <90 min; and Group C (n=15): Patients who undergone cardiac surgery with cardiopulmonary bypass time either 90 min or more. The difference of mean hemoglobin, total count of WBC, and platelet count on immediate post-operative period and at 7 days after surgery were statistically significant among the groups. The mean hematocrit value, fibrinogen level and coagulation profile were statistically significant between the two groups in comparison to pre-operative value. The mean cross-clamp time and bypass time were statistically significant between the two sub-groups of cardiopulmonary bypass population. The mean blood loss was more (1513.3 ± 307.9 mL) where the cardiopulmonary bypass was used for >90 min in comparison to other population. Prolong cardiopulmonary bypass time associated with more hemostatic abnormalities and complications can be minimized by shortening the bypass time.


Introduction
Cardiopulmonary bypass is a technique used to bypass the heart and lungs in order to facilitate heart surgery.It has been reported to be associated with hemostatic defect and activation of the inflammatory system. 1 The consequences of blood cell activation and plasma protein alteration during cardiopulmonary bypass prolong the bleeding time, increase the post-operative blood loss and necessity for massive infusion of blood lead to pulmonary function abnormality. 1, 2Massive transfusion can cause not only transmission of infection and circulatory overload, but also increase the mortality risk, longer stay in Intensive Care Unit and hospital, and increase the mortality. 3,4 6][7] In addition to thrombocytopenia, a qualitative platelet defect during the cardiopulmonary bypass has also been reported.The combination of a decrease in platelet number and altered platelet function are responsible for a major proportion of blood loss associated with cardiopulmonary bypass. 8- 10 Cardiopulmonary bypass has been reported to be associated with hemodilution in order to improve the oxygen delivery and tissue perfusion, and in a typical adult, the onset of cardiopulmonary bypass decreases the hematocrit from 40% to approximately 25%. 11Additionally, fibrinogen is known to bind extra-corporeal surfaces within minutes when blood passage through the cardiopulmonary bypass circuit.This bounded fibrinogen is conformationally altered in such a way that it is capable of binding to the resting glycoprotein IIb/IIIa receptor on platelets, thus responsible for more decrease in the circulatory platelets and fibrinogen and post-cardiopulmonary bypass bleeding. 10, 11][11] Cite this arti le: Ah ad J, Ra ja R, Saha H, Saklaye SMG, Begu M, Adhikary AB.Effe t of ardiopul o ary ypass o he ostasis i patie ts u dergoi g ardia surgery.Ba ga a dhu Sheikh Muji Med U i J.

Copyright:
The opyright of this arti le is retai ed y the author s [Atri utio CC-By .] A aila le at: .a glajol.ifo Therefore, the present study was designed to evaluate the association between the cardiopulmonary bypass and hemostatic defect in patient undergoing cardiac surgery and the after effect during peri-operative and post-operative period.

Statistical analysis
Statistical analyses were carried out using the Statistical Package for Social Sciences (SPSS) software and results were presented in tables.

Results
Total 60% of the patients belonged to the age above 50 years in Group A. The mean age was found 51.5 ± 4.7 years in Group A, 33.2 ± 10.2 years in Group B and 34.2 ± 11.4 years in Group C. The majority of patients were male and the difference of age was statistically significant (p<0.05)among the three groups.The difference of post-operative mean hemoglobin and RBC value on arrival at the intensive care unit, at 48 hours and at 7 days after surgery were statistically significant (p<0.05)among the three groups.The difference of post-operative mean total count of WBC and platelet were also statistically significant.The mean blood loss was 650.0 ± 280.7 mL in Group A, 683.5 ± 274.3 mL in Group B and 1513.3 ± 307.9 in Group C.Moreover, the difference of mean blood transfused was statistically significant (p<0.05)among the three groups (Table I).
In this study, the mean cross-clamp time was statistically significant between the two sub-groups Group B and C. The mean total bypass was found 64.2 ± 16.9 min in Group B and 204.1 ± 85.6 min in Group C, which was also statistically significant (p<0.05) between two groups.However, on arrival at Intensive Care Unit, after 48 hours and at 7 days after surgery, the coagulation profile like mean fibrinogen level, bleeding time, clotting time and prothrombin time were statistically significant (p<0.05)among the three groups (Table II).

Discussion
In this study, it was observed that the majority of study patients in Group A were male and the age difference was statistically significant (p<0.05)among the three groups.Group A includes mostly ischemic heart diseases patients and we do prefer coronary artery bypass without using cardiopulmonary bypass.The difference of post-operative mean hemoglobin level and RBC value on arrival at Intensive Care Unit, at 48 hours and at 7 days after surgery were statistically significant (p<0.05)among the three groups.Moreover, post-operative mean total count of WBC and platelet were also statistically significant.The mean total bypass time and cross-clamp time were statistically significant (p<0.05) between the study groups.However, coagulation profile like mean fibrinogen level, bleeding time, clotting time and prothrombin time were statistically significant.
There is scanty of literature where we have compared irrespective of age and sex for this study.2 This dissimilarity of present study may be due to involvement of miscellaneous type of patients including cardiopulmonary bypass group whereas in their study they include only CABG patients. 6, 8, 10, 13 In a study, Ascione et al. (2001) found hemoglobin level decreased more over time in the on-pump group despite this group requiring a significantly higher transfusion of red blood cells during the postoperative period. 13The findings are consistent with other authors. 10, 14, 15Mohnle et al. (2005)  demonstrate that changes like decreased platelet counts, rise in white blood cell count mainly because of increased neutrophils, and fall in hemoglobin and hematocrit levels, which is concordance to this study findings. 14Moreover, Moller and Steinbruchel (2003) demonstrated an increase in platelet activation after OPCAB and a temporary platelet dysfunction in the cardiopulmonary bypass group, which is also supported in several published literatures. 5, 10, 12, 15, 16A limitation of this study was that we did not measure the platelet functions.In another study, Holloway et al.  (1988) found that the decrease in platelet count during cardiopulmonary bypass was due to hemodilution for priming the extracorporeal circuit. 16everal authors also found that platelet count in the on-pump group show the typical time course previously reported during and after operations with cardiopulmonary bypass. 13,17  greater reduction of platelet count throughout the study observed in the on-pump group suggests a depletion caused by contact activation with extracorporeal surfaces, bubble oxygenator, cardiotomy suction, and filters by Weerasinghe and Taylor (1998). 18Weerasinghe and Taylor (1998) found that thrombocytopenia and its relation to post-operative bleeding are well documented in association with cardiopulmonary bypass. 18[25] The decline in the blood hemoglobin level at the end of the operation in the off-pump group might be related to intraoperative blood loss.However, the effects of hemodilution have to be considered because the infusion of colloid or crystalloid solutions is required during off-pump coronary operations to maintain the mean systemic pressure at greater than 60 mm Hg, particularly during the distal anastomoses.

Conclusion
Cardiopulmonary bypass assisted cardiac surgery is associated with hemostatic abnormalities, but shorter cardiopulmonary bypass time minimizes this complication.

Table I Demographic and hemodynamic data of the study population
Data are Mean ± SD; ICU-Intensive Care Unit 18, 19 Lamy et al. (2012) observed postoperative bleeding time was higher in the OPCAB

Table II Peri-operative coagulation profile of study patients
20ese data differ from those of larger trials, in which bleeding time in OPCAB group was lower compared to cardiopulmonary bypass group which is similar to this study.20Inanotherstudy,Puskasetal. (2003)found a significant reduction of postoperative bleeding time in OPCAB group when compared to on-pump group which is similar to other study findings.10, 15, 21,