The impact of blood conservation on outcomes in cardiac surgery: is it safe and effective?

BACKGROUND: Increasing evidence shows that perioperative blood transfusion in cardiac surgery is associated with increased postoperative morbidity and mortality and decreased long-term survival. Tolerance of "permissive anemia" is an important element of perioperative blood conservation strategy. The safety of tolerating perioperative anemia has been a significant deterrent for widespread application of blood conservation. This study examines whether blood conservation is equally safe or superior to the common practice of transfusion in cardiac surgery. METHODS: The total study population consisted of 32,449 patients who underwent isolated coronary artery bypass surgery from June 2000 until December 2004 with complete data from 17 institutions in the State of New Jersey. Englewood Hospital and Medical Center (EH) has a well-established blood conservation program. Five hundred eighty-six EH patients (blood conservation cohort) were compared with a propensity score-matched cohort of 586 patients from the other New Jersey institutions (OH-M) representing the common practice of transfusion. Outcomes were classified as very serious complications, serious complications, or neither (no very serious complication or serious complication). Analysis consisted of McNemar tests and multiple logistic regression. RESULTS: Fewer patients were transfused at EH compared with OH-M (10.6% versus 42.5%; p < 0.0001). Englewood Hospital had 5 (0.8%) deaths versus 15 (2.5%) in the OH-M group (p = 0.02). Of the EH patients, 11.1% experienced a very serious complication or serious complication versus 18.7% in the OH-M cohort (p = 0.0002). Transfusion was associated with an increased risk of an adverse outcome in both cohorts (EH: odds ratio, 7.3; 95% confidence interval, 3.7 to 14.4 versus OH-M: odds ratio, 4.6; 95% confidence interval, 2.8 to 7.7). CONCLUSIONS: Blood conservation is safe and effective in reducing transfusions. Tolerance of perioperative anemia, which is one of the main components of blood conservation, does not increase the risk of complications or death in cardiac surgery. Avoidance of transfusion reduces the risk of complications. This study further solidifies the relationship between transfusion and adverse outcome in cardiac surgery.

Postoperative blood loss and transfusion associated with use of Hextend in cardiac surgery patients at a blood conservation center.

BACKGROUND: Hydroxyethyl starch (HES) solutions are readily available colloids, but their widespread use is shadowed by controversies surrounding their effects on bleeding. This retrospective study was conducted to evaluate the relationship between Hextend (HEX; Hospira, Inc.) doses of 1 to 20 mL/kg and allogeneic transfusion and 24-hour chest tube drainage (CTD) in cardiac surgeries at a blood conservation center. STUDY DESIGN AND METHODS: After institutional review board approval, data on 748 patients undergoing coronary artery bypass grafting (CABG), valve, or combined CABG and valve surgeries were collected. Cases not receiving HEX (due to contraindications, e.g., renal failure, bleeding diathesis) or receiving more than 20 mL per kg HEX, not accepting transfusions, or requiring more extensive surgery were excluded, and the remaining 621 cases were analyzed. RESULTS: Overall transfusion rate and mean CTD were 12.7 percent and 460.4 mL, respectively. Patients who received transfusions received more HEX (10.8 mL/kg vs. 9.8 mL/kg; p = 0.043) but HEX per kg was not associated with higher transfusion rates in multivariate analysis (p = 0.077). HEX per kg was associated with CTD in both uni- and multivariate analyzes (p < 0.001) with 1.66 percent increase in CTD for every 1 mL per kg increase in HEX. CONCLUSIONS: Although HEX was associated with transfusion in univariate analysis and with CTD in uni- and multivariate analysis, the former was no longer significant when adjusted for other predictors of transfusion in our selected patient population at a blood conservation center. The clinical significance of the observed increase in CTD remains undetermined. To minimize transfusion and bleeding in these patients, it is recommended that HEX be used in amounts of not more than 20 mL per kg together with point-of-care coagulation tests and other blood conservation strategies.

Use of the Hemobag for modified ultrafiltration in a Jehovah's Witness patient undergoing cardiac surgery.

Modified ultrafiltration is an important technique to concentrate the patient's circulating blood volume and the residual whole blood in the extracorporeal circuit post-cardiopulmonary bypass. The Hemobag system is a device cleared by the US Food and Drug Administration and represents a novel and safe modification of traditional modified ultrafiltration systems. It is quick and easy to operate by the perfusionist during the hemoconcentration process. Hemoconcentration is accomplished by having the Hemobag "recovery loop" circuit separate from the extracorporeal circuit. This allows the surgeons to continue with surgery, decannulate, and administer protamine simultaneously while the Hemobag is in use. The successful use of the Hemobag in a Jehovah's Witness patient has not been previously described in the literature. This case report describes how to set up and operate the Hemobag in a Jehovah's Witness patient undergoing cardiac surgery that requires an extracorporeal circuit.

Composite aortic root replacement in acute type A dissection: time to rethink the indications?

OBJECTIVE: The indications for aortic root replacement in acute type A dissection are unclear. We reviewed the immediate and long-term outcome of consecutive patients in a series in which a low-threshold policy of composite aortic root replacement had evolved. METHODS: From a prospectively compiled aortic surgery database, we identified 162 patients who had either supracoronary interposition grafting, Group A (n=89), or composite root replacement, Group B (n=73) for acute type A dissection. Patients receiving total arch replacements were excluded. Operative and clinical details were analyzed and patient survival was compared to an age and gender matched census cohort. Need for reoperation on the proximal or distal aorta was also noted. Follow-up totaled 795.5 patient-years. RESULTS: Hospital mortality rates were identical in both groups (12.3%: 11 deaths in group A; 9 in group B). Chronic pulmonary disease, diabetes, malperfusion, hemodynamic compromise and aortic root dilatation were independent risk factors for hospital death. Actuarial survival estimates at 1, 5 and 10 years were 79% (71-88%), 64% (53-75%), and 55% (41-68%) for group A, and 79% (70-86%), 73% (62-83%), and 65% (52-78%) for group B (P=0.48). Age and operative patency of the ascending false lumen were independent risk factors for death after hospital discharge. Proximal aortic reoperation was required for four patients in group A and none in group B (P=0.085). CONCLUSION: A strategy of replacement rather than repair of the dissected aortic root for specific indications in type A dissection yielded high survival and low proximal reoperation rates. These results support an aggressive policy of composite root replacement in acute type A dissection.

Application of biological glue in repair of intracardiac structural defects.

BACKGROUND: BioGlue (Cryolife Inc, Kennesaw GA) was introduced as an alternative tissue sealant. Its most common application has been in repairs of acute dissections of the aorta. There is no reported experience with its use in the repair of intracardiac structural defects. METHODS: In 5 patients BioGlue was used as an adjunct in repairs of complex intracardiac structural defects. It was used during patch repair of posterior mitral annular defects in 2 patients and aortic annular defect in 1 patient in the presence of active endocarditis. It was also used in 1 patient with a chronic atrioventricular groove pseudoaneurysm following mitral valve replacement, and in 1 patient during repair of a postinfarction posterior ventricular septal rupture. RESULTS: There were no hospital or late deaths. Immediate intraoperative transesophageal echocardiography and late follow-up echocardiography documented complete and durable repair of all defects without recurrence. At follow-up all patients are in New York Heart Association class I-II, 6 to 29 months postoperatively. No patient has suffered late complications or exhibited signs of glue embolization. CONCLUSIONS: BioGlue was found to be an effective adjuvant to the standard techniques used for the repair of intracardiac structural defects of various etiologies. Long-term follow-up is recommended to determine its long-term safety in this application.

Predictors of transfusion requirements for cardiac surgical procedures at a blood conservation center.

BACKGROUND: Previous studies defining perioperative risk factors for allogeneic transfusion requirements in cardiac surgery were limited to highly selected cardiac surgery populations or were associated with high transfusion rates. The purpose of this study was to determine perioperative risk factors and create a formula to predict transfusion requirements for major cardiac surgical procedures in a center that practices a multimodality approach to blood conservation. METHODS: We performed an observational study on 307 consecutive patients undergoing coronary artery bypass grafting, valve, and combined (coronary artery bypass grafting and valve) procedures. An equation was derived to estimate the risk of transfusion based on preoperative risk factors using multivariate analysis. In patients with a calculated probability of transfusion of at least 5%, intraoperative predictors of transfusion were identified by multivariate analysis. RESULTS: Thirty-five patients (11%) required intraoperative or postoperative allogeneic transfusions. Preoperative factors as independent predictors for transfusions included red blood cell mass, type of operation, urgency of operation, number of diseased vessels, serum creatinine of at least 1.3 mg/dL, and preoperative prothrombin time. Intraoperative factors included cardiopulmonary bypass time, three or fewer bypass grafts, lesser volume of acute normovolemic hemodilution removed, and total crystalloid infusion of at least 2,500 mL. The derived formula was applied to a validation cohort of 246 patients, and the observed transfusion rates conformed well to the predicted risks. CONCLUSIONS: A multimodality approach to blood conservation in cardiac surgery resulted in a low transfusion rate. Identifying patients' risks for transfusion should alter patient management perioperatively to decrease their transfusion rate and make more efficient use of blood resources.

Diabetes and evidence of atherosclerosis are major risk factors for adverse outcome after elective thoracic aortic surgery.

BACKGROUND: To predict risk after elective repair of ascending aorta and aortic arch aneurysms, we studied 464 consecutive patients. METHODS: Adverse outcome (stroke or hospital death) was analyzed in 372 patients who underwent proximal repair and 92 patients who underwent aortic arch replacement from 1986 to the present. Preoperative risk factors with a P value less than.2 in a univariate analysis were entered into a multivariate model, and an equation incorporating independent risk factors was derived separately for proximal aorta and arch surgery. RESULTS: Age more than 65 years (P =.04), diabetes (P =.02), cause (P =.01), and prolonged total cerebral protection time (duration of hypothermic circulatory arrest and selective cerebral perfusion, P =.001) were significant univariate risk factors for elective proximal aortic repair. Diabetes (P =.005, odds ratio 5.1), atherosclerosis (P =.003, odds ratio 4.0), and dissection (P =.048, odds ratio 2.5) were independent factors. For elective arch surgery, female sex (P =.07), age more than 65 years (P =.04), coronary artery disease (P =.02), diabetes (P =.06), cause (P =.07), and prolonged total cerebral protection time (P =.025) were univariate risk factors. Female sex (P =.05, odds ratio 4.7), coronary artery disease (P =.02, odds ratio 6.5), diabetes (P =.13, odds ratio 4.0), and total cerebral protection time (P =.03, odds ratio 1.02/min) were independent factors. To calculate risk of adverse outcome (P), enter 1 if factor is present, 0 if absent, and estimate total cerebral protection time (in minutes). [equation: see text]. CONCLUSION: In this large series of patients, the presence of diabetes and manifestations of atherosclerosis emerge as extremely important risk factors for adverse outcome after ascending aorta or arch surgery, displacing age. Multivariate equations derived from these data allow more precise calculation of risk for each individual contemplating elective surgery.

Effect of aneurysm on the tensile strength and biomechanical behavior of the ascending thoracic aorta.

BACKGROUND: Rupture of an ascending thoracic aortic aneurysm (ATAA), which is associated with significant mortality, occurs when the mechanical forces acting on the aneurysm exceed the strength of the degenerated aortic wall. The purpose of this study was to evaluate changes in biomechanical properties of the aortic wall related to ATAA formation. METHODS: Ascending thoracic aortic aneurysm tissue was obtained from surgery; control (nonaneurysmal) aorta was obtained from autopsy. Tissue strips with longitudinal (LONG) or circumferential (CIRC) orientation were stretched to failure. Maximum tissue stiffness and tensile strength were determined from plots of stress (normalized force) versus strain (normalized deformation). Student's t test was used for all comparisons. RESULTS: Tensile strength of LONG (nATAA = 17, n(control) = 7) and CIRC (nATAA = 23, n(control) = 7) ATAA specimens were 29% and 34% less than that of control tissue, respectively (p < 0.05). Maximum tissue stiffness was 72% stiffer for LONG ATAA (p < 0.05) and 44% stiffer for CIRC ATAA (p = 0.06) than for control tissue, respectively. CONCLUSIONS: The data suggest that ATAA formation is associated with stiffening and weakening of the aortic wall, which may potentiate aneurysm rupture.

Bioprosthetic valved conduit aortic root reconstruction: the Mount Sinai experience.

BACKGROUND: Patients requiring aortic root reconstruction who are deemed unable to take anticoagulants offer unique challenges to the surgeon. For these patients, we have been manufacturing composite conduits intraoperatively using stented bioprostheses. METHODS: During the 10-year period from April 1992 until May 2002, 141 patients (105 male, 36 female) from 34 to 88 years of age underwent aortic root reconstruction with biological valved conduits. Diagnoses included dissection (n = 28, 9 acute type A), degenerative (64), atherosclerotic (32), anuloaortic ectasia (9), endocarditis (5), and other causes (3). Preoperative risk factors included hypertension (90), smoking (63), coronary artery disease (48), and diabetes (6). Valved conduits were mainly constructed from pericardial valves and impregnated Dacron grafts. Distal anastomosis was performed open in all cases except 6; the ascending aorta only was replaced in 63 patients, a hemiarch reconstruction was used in 71, and more extensive arch reconstruction in 7. Additional cardiac procedures were performed in 59 patients. RESULTS: Two deaths occurred in the operating room (biventricular failure). Late hospital mortality was 11 of 141 (7.8%) of which 6 (55%) were cardiac, 2 (18.2%) were infectious, 2 (18.2%) were of other complications and 1 (9.1%) was unknown. Three patients (2.1%) sustained permanent and 3 transient strokes. No structural deterioration of the valve and an approximately 86% freedom from thromboembolic events was observed during 5 years. CONCLUSIONS: For patients for whom anticoagulation is contraindicated or undesirable, reconstruction of the aortic root with a stented bioprosthetic valved conduit offers an acceptable alternative to mechanical prostheses.

Acute type B aortic dissection: surgical therapy.

BACKGROUND: Surgery for acute type B aortic dissection is associated with significant mortality. We report the results for 34 consecutive patients who underwent urgent surgery because they met criteria for operation during the acute phase (< 14 days) of acute type B dissection. METHODS: The average patient age was 64 (32 to 88) years. Indications for surgery were persistent pain (12), threatened exsanguination (18), malperfusion (renal [3], limb [3]), rapid aortic enlargement (4), and uncontrolled hypertension (1). The mean interval from onset of pain to operation was 7 (1 to 14) days. Resection included the proximal descending aorta in 32, the distal aortic arch in 10, extension to the diaphragm in 10, and involved a thoracoabdominal procedure in 3. Surgical techniques included hypothermic circulatory arrest (16 [47%]), distal bypass, monitoring of somatosensory-evoked potentials, sequential intercostal sacrifice (average, 5.6 pairs), cerebrospinal fluid drainage, and steroid administration. RESULTS: There was no hospital mortality. Important complications occurred in 16 patients (47%): 10 respiratory requiring tracheostomy, six infectious, four dialysis, two myocardial infarctions, and two neurologic (one transient stroke, one paraplegia). Mean intensive care unit and hospital stays were 10 (3 to 32) and 35 (7 to 107) days. Survival at 5 and 10 years was 80% and 57%, respectively (mean follow-up, 5.8 years). CONCLUSIONS: Patients meeting criteria for urgent surgery have a low perioperative risk for mortality and paraplegia, and are relatively free from long-term aorta-related complications. These findings warrant consideration of earlier surgery for appropriate patients with acute type B aortic dissection.

Multidisciplinary management of a Jehovah's Witness patient for the removal of a renal cell carcinoma extending into the right atrium.

PURPOSE: To highlight the management of a Jehovah's witness surgical patient presenting for cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest. CLINICAL FEATURES: A 47-yr-old male, Jehovah's Witness, with renal cell carcinoma was admitted for left radical nephrectomy and excision of tumour thrombus extending into the junction of the inferior vena cava (IVC) and right atrium (RA). The preoperative goals were to maximize red blood cell mass, delineate the extent of tumour extension and develop a surgical plan incorporating blood conservation strategies to minimize blood loss. A midline abdominal incision was made to optimize removal of the non-caval portion of the tumour from the intra-abdominal region. CPB and deep hypothermic circulatory arrest were instituted to aid in removing the tumour from the IVC and RA. Intraoperative blood conservation strategies included the use of acute normovolemic hemodilution, antifibrinolytics, cell salvage, point-of-care monitoring of heparin and protamine blood concentrations, leukocyte-depleting filter, and meticulous surgical techniques. The patient was successfully weaned from CPB and was transported to the cardiothoracic intensive care unit without complication. The patient was discharged home one week after the operation with a hemoglobin of 10.2 g x dL(-1) and a hematocrit of 31.2%. CONCLUSION: Multiple blood conservation techniques were employed to manage this Jehovah's Witness patient through complex cardiac surgery, which was previously denied to him at other institutions. The successful outcome of this patient, while respecting the right to refuse allogeneic blood products, is a result of a multidisciplinary collaboration as well as the application of established blood conservation techniques.

Rheumatoid involvement of the aortic arch.

The clinical course of rheumatoid arthritis may be complicated by cardiac involvement. Indeed, postmortem studies suggest rheumatoid involvement in up to 50% of pericardial, 5% of myocardial, and 60% of valvular specimens. Yet, in our search of the literature, we found only a single case report describing aortic valve replacement for rheumatoid valvulitis. This discrepancy may be related to the paucity of symptoms in this sedentary group of patients. A complete cardiac evaluation of patients with rheumatoid arthritis is recommended to select those with significant valvular involvement for timely surgical intervention prior to the development of irreversible left ventricular dysfunction. Two patients who benefitted from aortic valve replacement for rheumatoid valvular disease are presented.