Role of hemodilutional anemia and transfusion during cardiopulmonary bypass in renal injury after coronary revascularization: Implications on operative outcome*

Department of Cardiovascular Surgery, St. Vincent Mercy Medical Center, Toledo, OH, USA.
Critical Care Medicine (Impact Factor: 6.31). 08/2005; 33(8):1749-56. DOI: 10.1097/01.CCM.0000171531.06133.B0
Source: PubMed

ABSTRACT Acute renal injury and failure (ARF) after cardiopulmonary bypass (CPB) has been linked to low on-pump hematocrit (hematocrit). We aimed to 1) elucidate if and how this relation is modulated by the duration of CPB (TCPB) and on-pump packed red blood cell transfusions and 2) to quantify the impact of post-CPB renal injury on operational outcome and resource utilization.
Retrospective review.
A Northwest Ohio community hospital.
Adult coronary artery bypass surgery patients with CPB but no preoperative renal failure.
We quantified post-CPB renal injury via 1) the peak postoperative change in serum creatinine (Cr) level relative to pre-CPB values (%DeltaCr) and 2) ARF, defined as the coincidence of post-CPB Cr > or =2.1 mg/dL and >2 times pre-CPB Cr. The separate effects of lowest hematocrit, intraoperative packed RBC transfusions, and TCPB on %DeltaCr and ARF were derived via multivariate regression, overlapping quintile subgroup analyses, and propensity matching. Lowest hematocrit (22.0% +/- 4.6% sd), TCPB (94 +/- 35 mins), and pre-CPB Cr (1.01 +/- 0.23 mg/dL) varied widely. %DeltaCr varied substantially (24 +/- 57%), and ARF was documented in 89 patients (5.1%). Both %DeltaCr (p < .001) and ARF (p < .001) exhibited sigmoidal dose-dependent associations to lowest hematocrit that were 1) modulated by TCPB such that the renal injury was exacerbated as TCPB increased, 2) worse in patients with relatively elevated pre-CPB Cr (> or =1.2 mg/dL), and 3) worse with intraoperative packed red blood cell transfusions (n = 385; 21.9%), in comparison with patients at similar lowest hematocrit. Operative mortality (p < .01) and hospital stays (p < .001) were increased systematically and significantly as a function of increased post-CPB renal injury.
CPB hemodilution to hematocrit <24% is associated with a systematically increased likelihood of renal injury (including ARF) and consequently worse operative outcomes. This effect is exacerbated when CPB is prolonged with intraoperative packed red blood cell transfusions and in patients with borderline renal function. Our data add to the concerns regarding the safety of currently accepted CPB practice guidelines.

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    • "It has been shown that low preoperative haematocrit, small body size and female gender predispose patients to severe haemodilution , necessitating intraoperative blood transfusion [15] [16]. The latter, however, carries an increased risk of postoperative complications such as sternal wound infections, renal and pulmonary dysfunction, prolonged intensive care and hospital stay and increased operative mortality [17] [18]. "
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    ABSTRACT: OBJECTIVES Many cardiac procedures using cardiopulmonary bypass (CPB) still require intraoperative transfusion. Retrograde autologous priming (RAP) has been introduced to decrease haemodilution and the blood transfusion rate. This study is designed to determine the influence or RAP on intraoperative haematocrit, transfusion and its clinical consequences.METHODS The RAP effect was retrospectively studied in 753 patients during contemporary cardiac surgery, targeting a haematocrit of 25%. Multivariate linear regression analysis was performed to identify the independent factors influencing intraoperative haematocrit, transfusion rate and transfusion quantity.RESULTSRAP was used in 498 patients and compared with 255 controls. RAP decreased the haemodilution level (nadir haematocrit 26.8 standard deviation [SD] 4.0% in RAP vs 25.8 SD 3.6% in controls; P = 0.001) and transfusion frequency (26.1 vs 33.3%, P = 0.04), despite smaller patients (body surface area [BSA] 1.86 SD 0.20 m2 vs 1.91 SD 0.21 m2 in RAP vs controls; P = 0.002) with lower preoperative haematocrit (38.9 SD 4.4% vs 40.5 SD 4.6%; P < 0.001). Optimal RAP volume was overall 475 ml (ROC area 0.55; 95% confidence interval [CI] 0.50-0.60; P = 0.04) and 375 ml in patients with BSA <1.7 m2 (ROC area 0.63; 95% CI 0.54-0.73; P = 0.008) to decrease the transfusion incidence. Multivariate analysis revealed RAP volume as a significant determinant of nadir haematocrit (β = 0.003, 95% CI 0.002-0.004, P < 0.001) and transfusion rate (odds ratio (OR) = 0.997, 95% CI 0.996-0.999, P < 0.001), independent of BSA, gender and preoperative haematocrit.CONCLUSION Retrograde autologous priming is an effective adjunct to decrease the blood transfusion rate, coping with the CPB-related haemodilution and its adverse clinical effects. A RAP volume individualized to each patient offers most benefit as part of a multidisciplinary blood conservation approach.
    Interactive Cardiovascular and Thoracic Surgery 03/2013; 16(6). DOI:10.1093/icvts/ivt085 · 1.16 Impact Factor
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    • "Recent clinical studies have indicated that the use of an ECC system may be associated with depressed organ function and poor outcome following CABG surgery [23] [24]. In this respect, the kidneys are especially susceptible due to their particularly complex microvascular organization and their high demand for oxygen [25]. "
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    ABSTRACT: OBJECTIVES To reduce the complications associated with cardiopulmonary bypass (CPB) during cardiac surgery, many modifications have been made to conventional extracorporeal circulation systems. This trend has led to the development of miniaturized extracorporeal circulation systems. Cardiac surgery using conventional extracorporeal circulation systems has been associated with significantly reduced microcirculatory perfusion, but it remains unknown whether this could be prevented by an mECC system. Here, we aimed to test the hypothesis that microcirculatory perfusion decreases with the use of a conventional extracorporeal circulation system and would be preserved with the use of an miniaturized extracorporeal circulation system.METHODS Microcirculatory density and perfusion were assessed using sublingual side stream dark-field imaging in patients undergoing on-pump coronary artery bypass graft (CABG) surgery before, during and after the use of either a conventional extracorporeal circulation system (n = 10) or a miniaturized extracorporeal circulation system (n = 10). In addition, plasma neutrophil gelatinase-associated lipocalin and creatinine levels and creatinine clearance were assessed up to 5 days post-surgery to monitor renal function.RESULTSAt the end of the CPB, one patient in the miniaturized extracorporeal circulation-treated group and five patients in the conventional extracorporeal circulation-treated group received one bag of packed red blood cells (300 ml). During the CPB, the haematocrit and haemoglobin levels were slightly higher in the miniaturized extracorporeal circulation-treated patients compared with the conventional extracorporeal circulation-treated patients (27.7 ± 3.3 vs 24.7 ± 2.0%; P = 0.03; and 6.42 ± 0.75 vs 5.41 ± 0.64 mmol/l; P < 0.01). The density of perfused vessels with a diameter <25 μm (i.e. perfused vessel density) decreased slightly in the conventional extracorporeal circulation-treated group from 16.4 ± 3.8 to 12.8 ± 3.3 mm/mm2 (P < 0.01) and remained stable in the miniaturized extracorporeal circulation-treated group (16.3 ± 2.7 and 15.2 ± 2.9 mm/mm2 before and during the pump, respectively). Plasma neutrophil gelatinase-associated lipocalin levels were increased following the use of extracorporeal circulation in both groups, and no differences were observed between the groups. Plasma creatinine levels and creatinine clearance were not affected by CABG surgery or CPB.CONCLUSIONS The results from this relatively small study suggest that the use of the miniaturized extracorporeal circulation system is associated with a statistically significant (but clinically insignificant) reduction in haemodilution and microcirculatory hypoperfusion compared with the use of the conventional extracorporeal circulation system. © 2012 The Author 2012. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
    Interactive Cardiovascular and Thoracic Surgery 06/2012; 15(3):364-70. DOI:10.1093/icvts/ivs271 · 1.16 Impact Factor
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    • "Since plasma fHb concentrations of 6 μmol/l have been shown to significantly impair the NO metabolism in vivo [16], and levels over 10 μmol/l have been linked to the development of renal injury and renal dysfunction [18], excessive pRBC transfusion may potentially decrease microcirculatory blood flow and contribute to organ compromise in these patients. Indeed, transfusion of pRBCs to treat anemia during cardiopulmonary bypass has been shown to be independently associated with increased urinary markers of intestinal damage, renal injury, and deterioration of kidney function compared with untreated anemic patients [33,34]. A similar independent association between pRBC transfusions and worse outcome was found in anemic critically ill patients [35]. "
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    ABSTRACT: Introduction The increasing number of reports on the relation between transfusion of stored red blood cells (RBCs) and adverse patient outcome has sparked an intense debate on the benefits and risks of blood transfusions. Meanwhile, the pathophysiological mechanisms underlying this postulated relation remain unclear. The development of hemolysis during storage might contribute to this mechanism by release of free hemoglobin (fHb), a potent nitric oxide (NO) scavenger, which may impair vasodilation and microcirculatory perfusion after transfusion. The objective of this prospective observational pilot study was to establish whether RBC transfusion results in increased circulating fHb levels and plasma NO consumption. In addition, the relation between increased fHb values and circulating haptoglobin, its natural scavenger, was studied. Methods Thirty patients electively received 1 stored packed RBC unit (n = 8) or 2 stored packed RBC units (n = 22). Blood samples were drawn to analyze plasma levels of fHb, haptoglobin, and NO consumption prior to transfusion, and 15, 30, 60 and 120 minutes and 24 hours after transfusion. Differences were compared using Pearson's chi-square test or Fisher's exact test for dichotomous variables, or an independent-sample t test or Mann-Whitney U test for continuous data. Continuous, multiple-timepoint data were analyzed using repeated one-way analysis of variance or the Kruskall-Wallis test. Correlations were analyzed using Spearman or Pearson correlation. Results Storage duration correlated significantly with fHb concentrations and NO consumption within the storage medium (r = 0.51, P < 0.001 and r = 0.62, P = 0.002). fHb also significantly correlated with NO consumption directly (r = 0.61, P = 0.002). Transfusion of 2 RBC units significantly increased circulating fHb and NO consumption in the recipient (P < 0.001 and P < 0.05, respectively), in contrast to transfusion of 1 stored RBC unit. Storage duration of the blood products did not correlate with changes in fHb and NO consumption in the recipient. In contrast, pre-transfusion recipient plasma haptoglobin levels inversely influenced post-transfusion fHb concentrations. Conclusion These data suggest that RBC transfusion can significantly increase post-transfusion plasma fHb levels and plasma NO consumption in the recipient. This finding may contribute to the potential pathophysiological mechanism underlying the much-discussed adverse relation between blood transfusions and patient outcome. This observation may be of particular importance for patients with substantial transfusion requirements.
    Critical care (London, England) 05/2012; 16(3):R95. DOI:10.1186/cc11359 · 4.48 Impact Factor
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