Reoperation for bleeding in patients undergoing coronary artery bypass surgery: incidence, risk factors, time trends, and outcomes

Coronary artery bypass grafting: Part 1--the evolution over the first 50 years

Surgical treatment for angina pectoris was first proposed in 1899. Decades of experimental surgery for coronary artery disease finally led to the introduction of coronary artery bypass grafting (CABG) in 1964. Now that we are approaching 50 years of CABG experience, it is appropriate to summarize the advancement of CABG into a procedure that is safe and efficient. This review provides a historical recapitulation of experimental surgery, the evolution of the surgical techniques and the utilization of CABG. Furthermore, data on contemporary clinical outcomes are discussed.

Safe application of a restrictive transfusion protocol in moderate-risk patients undergoing cardiac operations

BACKGROUND

Perioperative red blood cell transfusion is associated with adverse outcomes after cardiac operations. Although restrictive transfusion protocols have been developed, their safety and efficacy are not well demonstrated, and considerable variation in transfusion practice persists. We report our experience with a restrictive transfusion protocol.

METHODS

We analyzed the outcomes in 409 patients undergoing cardiac operations enrolled in a trial conducted at 30 centers worldwide. Blood products were administered on the basis of a transfusion algorithm applied across all centers, with a restrictive transfusion trigger of hemoglobin less than or equal to 6 g/dL. Transfusion was acceptable but not mandatory for hemoglobin 6 to 8 g/dL. For hemoglobin 8 to 10 g/dL, transfusion was acceptable only with evidence for end-organ ischemia.

RESULTS

The patient population was moderately complex, with 20.5% having combined procedures and 29.6% having nonelective operations. The mean EuroSCORE for the population was 4.3, which predicted a substantial incidence of morbidity and mortality. Actual outcomes were excellent, with observed mortality of 0.49% and rates of cerebrovascular accident, myocardial infarction, and acute renal failure 1.2%, 6.1%, and 0.98%, respectively. The frequency of red blood cell transfusion was 33.7%, which varied significantly by center. Most transfusions (71.9%) were administered for hemoglobin 6 to 8 g/dL; 21.4% were administered for hemoglobin 8 to 10 g/dL with evidence for end-organ ischemia; 65.0% of patients avoided allogeneic transfusion altogether.

CONCLUSIONS

A restrictive transfusion protocol can be safely applied in the care of moderate-risk patients undergoing cardiac operations. This strategy has significant potential to reduce transfusion and resource utilization in these patients, standardize transfusion practices across institutions, and increase the safety of cardiac operations.

Safety and Efficacy Outcomes of Preoperative Aspirin in Patients Undergoing Coronary Artery Bypass Grafting

Background:

The administration of aspirin is traditionally discontinued prior to coronary artery bypass grafting (CABG), given a potential risk of excessive postoperative bleeding. Few studies have previously suggested the benefits of continuing aspirin until the time of surgery. The primary aim of this review is to evaluate the effects of preoperative aspirin therapy on several clinically important outcomes in patients undergoing CABG.

Methods:

A meta-analysis of eligible studies of patients undergoing CABG, reporting preoperative aspirin in comparison with no aspirin/placebo and our outcomes, was carried out. The safety outcomes included postoperative bleeding, packed red blood cell (PRBC) transfusion requirements, and reoperation for bleeding. The efficacy outcomes included perioperative myocardial infarction (MI), cerebrovascular accidents (CVAs), and mortality.

Results:

In 8 randomized controlled trials (RCTs; n = 1538), preoperative aspirin increased postoperative bleeding (difference in means = 132.30 mL; 95 % confidence interval [CI] 47.10-217.51; P = .002), PRBC transfusion requirements (difference in means = 0.67 units; 95% CI 0.10-1.24; P = .02), and reoperation for bleeding (odds ratio [OR] = 1.76; 95% CI 1.05-2.93; P = .03). In 19 observational studies (n = 19551), preoperative aspirin increased postoperative bleeding (difference in means = 132.74 mL; 95% CI 45.77-219.72; P = .003) and PRBC transfusion requirements (difference in means = 0.19 units; 95% CI 0.02-0.35; P = .02) but not reoperation for bleeding (OR = 1.13; 95% CI 0.91-1.42; P = .27). Subgroup analyses for RCTs demonstrated that aspirin given at doses ≤ 100 mg/d might not increase the postoperative bleeding, and the dose of 325 mg/d might not be a cutoff value that has clinical and statistical significance. No statistically significant differences in the rate of perioperative MI, CVAs, or mortality were seen between the 2 groups.

Conclusions:

Preoperative aspirin therapy is associated with increased postoperative bleeding, PRBC transfusion requirements, and reoperation for bleeding in patients undergoing CABG. Doses lower than 100 mg/d may minimize the risk of bleeding. Additional RCTs are needed to assess the effects of preoperative aspirin on the safety and efficacy outcomes in patients undergoing CABG.

Process improvement in cardiac surgery: development and implementation of a reoperation for bleeding checklist

OBJECTIVE

High-performing health care organizations differentiate themselves by focusing on continuous process improvement initiatives aimed at enhancing patient outcomes. Reoperation for bleeding is an event associated with considerable morbidity risk. Hence, our primary objective was to develop and implement a formal operative checklist to reduce technical reasons for postoperative bleeding.

METHODS

From January 1, 2011, through June 30, 2012, 5812 cardiac surgical procedures were performed at Cleveland Clinic (Cleveland, OH). A multidisciplinary team developed a simple, easy-to-perform hemostasis checklist based on the most common sites of bleeding. An extensive educational in-service was performed before limited, then universal, checklist implementation. Geometric charts were used to track the number of cases between consecutive reoperations for bleeding. We compared these before (phase 0) and after the first limited implementation phase (phase 1) and the universal implementation phase (phase 2) of the checklist.

RESULTS

The average number of cases between consecutive reoperations for bleeding increased from 32 in phase 0 to 53 in both phase 1 (P = .002) and phase 2 (P = .01).

CONCLUSIONS

A substantial reduction in reoperation for bleeding cases followed implementation of a formalized hemostasis checklist. Our findings underscore the important influence of memory aids that focus attention on surgical techniques to improve patient outcomes in a complex, operative work environment.

Blood transfusion and infection after cardiac surgery

Cardiac surgery is the largest consumer of blood products in medicine; although believed life saving, transfusion carries substantial adverse risks. This study characterizes the relationship between transfusion and risk of major infection after cardiac surgery. In all, 5,158 adults were prospectively enrolled to assess infections after cardiac surgery. The most common procedures were isolated coronary artery bypass graft surgery (31%) and isolated valve surgery (30%); 19% were reoperations. Infections were adjudicated by independent infectious disease experts. Multivariable Cox modeling was used to assess the independent effect of blood and platelet transfusions on major infections within 60 ± 5 days of surgery. Red blood cells (RBC) and platelets were transfused in 48% and 31% of patients, respectively. Each RBC unit transfused was associated with a 29% increase in crude risk of major infection (p < 0.001). Among RBC recipients, the most common infections were pneumonia (3.6%) and bloodstream infections (2%). Risk factors for infection included postoperative RBC units transfused, longer duration of surgery, and transplant or ventricular assist device implantation, in addition to chronic obstructive pulmonary disease, heart failure, and elevated preoperative creatinine. Platelet transfusion decreased the risk of infection (p = 0.02). Greater attention to management practices that limit RBC use, including cell salvage, small priming volumes, vacuum-assisted venous return with rapid autologous priming, and ultrafiltration, and preoperative and intraoperative measures to elevate hematocrit could potentially reduce occurrence of major postoperative infections.

Antifibrinolytic agents in current anaesthetic practice

Antifibrinolytic drugs have become almost ubiquitous in their use during major surgery when bleeding is expected or commonplace. Inhibition of the fibrinolytic pathway after tissue injury has been consistently shown to reduce postoperative or traumatic bleeding. There is also some evidence for a reduction of perioperative blood transfusion. However, evidence of complications associated with exaggerated thrombosis also exists, although this appears to be influenced by the choice of the individual agent and the dose administered. There is controversy over the use of the serine protease inhibitor aprotinin, whose license was recently withdrawn but may shortly become available on the market again. In the UK, tranexamic acid, a tissue plasminogen and plasmin inhibitor, is most commonly used, with evidence for benefit in cardiac, orthopaedic, urological, gynaecological, and obstetric surgery. In the USA, ε-aminocaproic acid, which also inhibits plasmin, is commonly used. We have reviewed the current literature for this increasingly popular class of drugs to support clinical judgement in daily anaesthetic practice.

Monitoring incomplete heparin reversal and heparin rebound after cardiac surgery

OBJECTIVES

To assess the incidence of incomplete heparin reversal and heparin rebound after cardiac surgery with cardiopulmonary bypass (CPB) and the ability of the activated coagulation time (ACT) and thromboelastography (TEG) to detect these phenomena.

DESIGN

Prospective single-center study.

SETTING

University hospital.

PARTICIPANTS

Forty-one patients undergoing elective cardiac surgery with CPB and with normal preoperative TEG parameters.

INTERVENTIONS

ACT, TEG, and plasma heparin levels were measured in all patients at 5 different times between 20 minutes and 3 hours after protamine administration. The variability of TEG reaction time (R) with and without heparinase (delta-R [DR]) was used to detect the presence of residual heparin.

MEASUREMENTS AND MAIN RESULTS

Plasma heparin expressed as anti-FXa activity was detected in 180 (88%) samples. At univariate analysis, ACT, R-kaolin (R-k), and DR significantly correlated with plasma heparin concentration (respectively, p = 0.007, p = 0.006, and p = 0.002). At multivariate analysis, R-k and DR remained associated with plasma heparin concentration (respectively, p = 0.014 and p = 0.004). Greater quartiles of heparin were associated with higher values of R-k and DR. Combined procedures had significantly lower DR than isolated procedures (p = 0.017), and CPB time and heparinization time positively correlated with R-k (respectively, p = 0.044 and p = 0.022). No association was observed between heparin concentration, ACT, and TEG parameters with postoperative bleeding and need for blood and blood components transfusions.

CONCLUSIONS

Heparin rebound and incomplete heparin reversal are very common phenomena after cardiac surgery with CPB; ACT is not able to detect residual heparin activity, whereas TEG analysis with and without heparinase allows the diagnosis of heparin rebound.

Time from adenosine di-phosphate receptor antagonist discontinuation to coronary bypass surgery in patients with acute coronary syndrome: meta-analysis and meta-regression

BACKGROUND

Adenosine di-phosphate receptor antagonists (ADPRAs) blunt hemostasis for several days after administration. This effect, aimed at preventing cardiac ischemic complications particularly in patients with acute coronary syndromes (ACS), may increase perioperative bleeding in the case of cardiac surgery. Practice Guidelines recommend withholding ADPRAs for at least 5days prior to surgery, though with a weak base of evidence. The purpose of this study was to systematically review observational and experimental studies of early or late preoperative discontinuation of ADPRAs prior to coronary artery bypass grafting (CABG) for patients with ACS.

METHODS

MEDLINE, EMBASE, the Cochrane Library databases up to December 2011; and reference lists. Observational and experimental studies that compared early ADPRA discontinuation with late discontinuation, or no discontinuation, in patients with ACS undergoing CABG.

RESULTS

There were 19 studies, including 14,046 participants, 395 deaths and 309 reoperations due to bleeding. ADPRA late discontinuation up to CABG was associated with an increased risk of postoperative mortality (OR 1.46, 95% confidence interval (CI) 1.10 to 1.93) and reoperations due to bleeding (OR 2.18; 95% CI 1.47 to 2.62). Between-study heterogeneity was low. Meta-analysis limited to high quality or prospective studies gave consistent results. In most instances, the 95% prediction intervals for summary risk estimates confirmed the risk across study groups.

CONCLUSIONS

ADPRA late discontinuation prior to CABG is associated with an increased risk of death and reoperations due to bleeding in patients with ACS. The confidence in the estimates of risk for late discontinuation is moderate to high.

Cardiac tamponade after removal of temporary pacer wires

BACKGROUND

After removal of temporary pacemaker wires, nurses measure vital signs frequently to assess for cardiac tamponade; however, evidence for this procedure is limited.

OBJECTIVES

To determine risk factors for cardiac tamponade after temporary pacemaker wire removal.

METHODS

Retrospective review of data for coronary artery bypass graft and valve surgery (N = 23 717) performed from January 1999 to December 2008. Patients were categorized by reason for reoperation: bleeding less than 3 days after initial surgery (n = 812, group 1), bleeding 3 days or more after index surgery but not for cardiac tamponade (n = 171, group 2), bleeding 3 days or more after index surgery for cardiac tamponade after temporary pacemaker wire removal (n = 23, group 3), and no reoperation (n = 22 711, group 4).

RESULTS

Less than 1% (9.7 cases/10 000) of patients required reoperation for cardiac tamponade after removal of temporary pacer wires. Of patient-related factors studied, only smoking history differed for group 3 vs group 1 (P = .03) and group 2 (P = .01). Of vital sign changes, 1 patient (4%) had tachycardia and 3 patients had cardiac arrest, but only 1 of the 3 had hypotension before the arrest. In total, 12 patients (52%) had hypotension; however, it was mild or intermittent in 5 cases, and did not occur within the 4 hours after wire removal in 3 cases. After removal of temporary pacing wires, common early signs/symptoms were bleeding (26%) and dyspnea (26%). Other documented changes were pressure in the chest, diaphoresis, cold and clammy skin, dizziness, and mental status changes.

CONCLUSIONS

Tamponade related to pacer wire removal was rare and not consistently associated with changes in vital signs. Dyspnea, bleeding, and other factors may indicate early onset of cardiac tamponade after removal of temporary pacer wires.

Association between major perioperative hemorrhage and stroke or Q-wave myocardial infarction

BACKGROUND

Hemorrhage is associated with ischemic complications in cardiac patients. The nature of this relationship in surgical patients is unknown.

METHODS AND RESULTS

We examined the association between major perioperative hemorrhage and stroke or myocardial infarction among adults who underwent surgery from 2005 through 2009 at centers participating in the National Surgical Quality Improvement Program. We excluded patients with emergent, trauma-related, transplantation, cardiac, or neurological operations. Major hemorrhage was defined as bleeding necessitating transfusion of >4 U of packed red blood cells or whole blood. Stroke was defined as focal brain dysfunction lasting ≥24 hours from a vascular cause. A diagnosis of myocardial infarction required new ECG Q waves. Outcomes were assessed from surgery until 30 days afterward. Among 651,775 patients who underwent surgery, 5233 (0.80%) experienced major hemorrhage, 1575 (0.24%) developed Q-wave myocardial infarction, and 1321 (0.20%) suffered a stroke. In Cox proportional hazards analyses controlling for vascular risk factors, illness severity, and type of surgery, hemorrhage was independently associated with subsequent stroke (hazard ratio, 2.5; 95% confidence interval, 1.9-3.3) and subsequent Q-wave myocardial infarction (hazard ratio, 2.7; 95% confidence interval, 2.1-3.4). Interaction terms revealed no significant variation in these associations by age, sex, or type of surgery. Our results were robust across multiple sensitivity analyses.

CONCLUSIONS

Major perioperative hemorrhage is associated with subsequent stroke and myocardial infarction in patients undergoing noncardiac, nonneurological surgery. This suggests the need for randomized trials to guide perioperative use of antiplatelet drugs, which affect the risk of both bleeding and vascular events.

Estimating the risk of complications related to re-exploration for bleeding after adult cardiac surgery: a systematic review and meta-analysis

OBJECTIVE

The aim of this study was to evaluate the impact of re-exploration for bleeding after cardiac surgery on the immediate postoperative outcome.

METHODS

Systematic review of the literature and meta-analysis of data on re-exploration for bleeding after adult cardiac surgery were performed.

RESULTS

The literature search yielded eight observational studies reporting on 557,923 patients and were included in the present analysis. Patients requiring re-exploration were significantly older, more frequently males, had a higher prevalence of peripheral vascular disease and preoperative exposure to aspirin, and more frequently underwent urgent/emergency surgery. Re-exploration was associated with significantly increased risk ratio (RR) of immediate postoperative mortality (RR 3.27, 95% confidence interval (CI) 2.44-4.37), stroke, need of intra-aortic balloon pump, acute renal failure, sternal wound infection, and prolonged mechanical ventilation. The pooled analysis of four studies (two being propensity score-matched pairs analysis) reporting adjusted risk for mortality led to an RR of 2.56 (95%CI 1.46-4.50). Studies published during the last decade tended to report a higher risk of re-exploration-related mortality (RR 4.30, 95%CI 3.09-5.97) than those published in the 1990s (RR 2.75, 95%CI 2.06-3.66).

CONCLUSIONS

This study suggests that re-exploration for bleeding after cardiac surgery carries a significantly increased risk of postoperative mortality and morbidity.

Management of the clotting system: a European perspective

PURPOSE OF REVIEW

Coagulation management remains a challenge for anesthesiologists involved in cardiovascular surgery as the population undergoing surgery becomes older and presents with more comorbidities. These patients are frequently treated with one or more agents that directly affect coagulation. This review will discuss what is known and the treatments available to manage coagulation in the perioperative setting of cardiac surgery.

RECENT FINDINGS

New antithrombotics will be discussed as well as their proposed substitution in the preoperative period. The review will also describe the different products available in Europe for the treatment of bleeding and coagulopathy. Finally, the use of new monitoring devices will be discussed.

SUMMARY

The introduction of new drugs with different mechanisms of action adds to the complexity of coagulation management during cardiovascular surgery. Monitoring needs to be developed and improved, especially for evaluating platelet function.

Individual surgeon's impact on the risk of re-exploration for excessive bleeding after coronary artery bypass surgery

OBJECTIVE

Excessive bleeding requiring re-exploration is a severe complication that may affect the outcome after coronary artery bypass grafting. The authors hypothesized that surgeon performance may contribute significantly to such a complication.

DESIGN

Retrospective.

SETTING

Tertiary referral center in a university hospital.

PARTICIPANTS

Two thousand one patients.

INTERVENTIONS

Isolated coronary artery bypass grafting.

RESULTS

Re-exploration for bleeding was performed in 113 patients (5.3%). Re-exploration was performed ≥3 days after surgery in 11 patients. The surgical site of bleeding was identified in 83 patients (73.5%). Rates of re-exploration for excessive bleeding ranged from 1.4% to 11.7% according to different surgeons (p < 0.0001). When adjusted for the additive European System for Cardiac Operative Risk Evaluation, re-exploration for bleeding was associated with increased risks of low-cardiac-output syndrome (odds ratio [OR] 2.239, 95% confidence interval [CI] 1.328-3.777), prolonged need for inotropes (OR 1.894, 95% CI 1.198-2.994), and an intensive care unit stay ≥5 days (OR 2.129, 95% CI 1.202-3.770). Logistic regression showed that an individual surgeon (p < 0.0001), preoperative body mass index <25 kg/m(2) (OR 2.733, 95% CI 2.145-3.481), and estimated glomerular filtration rate <30 mL/min/1.73 m(2) (OR 3.891, 95% CI 1.669-9.076) were independent predictors of re-exploration for excessive bleeding. An individual surgeon also was an independent predictor of a postoperative blood loss ≥1,600 mL.

CONCLUSIONS

An individual surgeon has a major impact on postoperative bleeding, and a meticulous surgical technique is expected to decrease significantly such a severe complication.

Preoperative thienopyridine use and outcomes after surgery: a systematic review

BACKGROUND

Although studies have demonstrated excess risk of ischemic events if aspirin is withheld preoperatively, it is unclear whether preoperative thienopyridine use influences postoperative outcomes.

METHODS

We conducted a systematic review of 37 studies (31 cardiac and 6 noncardiac surgery, 3 randomized, 34 observational) comparing postoperative outcomes in patients who were versus were not exposed to thienopyridine in the 5 days before surgery.

RESULTS

Exposure to thienopyridine in the 5 days preceding surgery (compared with no exposure) was not associated with any reduction in postoperative myocardial infarction (23 studies, 12,872 patients, 3.4% vs 3.0%, odds ratio [OR] 0.98; 95% confidence interval [CI], 0.72-1.34), but was associated with increased risks of stroke (16 studies, 10,265 patients, 1.9% vs 1.4%, OR 1.54; 95% CI, 1.08-2.20), reoperation for bleeding (32 studies, 19,423 patients, 4.3% vs 1.8%, OR 2.62; 95% CI, 1.96-3.49), and all-cause mortality (28 studies, 22,990 patients, 3.7% vs 2.6%, OR 1.38; 95% CI, 1.13-1.69). Results were identical when analyses were restricted to long-term users of thienopyridines who continued versus held the medication in the 5 days before surgery. Although all associations were similar in direction for the subset of patients undergoing noncardiac surgery, 97% of the outcome data in this meta-analysis came from cardiac surgery trials.

CONCLUSIONS

These data support withholding thienopyridines 5 days before cardiac surgery; there was insufficient evidence to make definitive recommendations for elective noncardiac surgery although the direction and magnitude of associations were similar.

2011 update to the Society of Thoracic Surgeons and the Society of Cardiovascular Anesthesiologists blood conservation clinical practice guidelines

BACKGROUND

Practice guidelines reflect published literature. Because of the ever changing literature base, it is necessary to update and revise guideline recommendations from time to time. The Society of Thoracic Surgeons recommends review and possible update of previously published guidelines at least every three years. This summary is an update of the blood conservation guideline published in 2007.

METHODS

The search methods used in the current version differ compared to the previously published guideline. Literature searches were conducted using standardized MeSH terms from the National Library of Medicine PUBMED database list of search terms. The following terms comprised the standard baseline search terms for all topics and were connected with the logical 'OR' connector--Extracorporeal circulation (MeSH number E04.292), cardiovascular surgical procedures (MeSH number E04.100), and vascular diseases (MeSH number C14.907). Use of these broad search terms allowed specific topics to be added to the search with the logical 'AND' connector.

RESULTS

In this 2011 guideline update, areas of major revision include: 1) management of dual anti-platelet therapy before operation, 2) use of drugs that augment red blood cell volume or limit blood loss, 3) use of blood derivatives including fresh frozen plasma, Factor XIII, leukoreduced red blood cells, platelet plasmapheresis, recombinant Factor VII, antithrombin III, and Factor IX concentrates, 4) changes in management of blood salvage, 5) use of minimally invasive procedures to limit perioperative bleeding and blood transfusion, 6) recommendations for blood conservation related to extracorporeal membrane oxygenation and cardiopulmonary perfusion, 7) use of topical hemostatic agents, and 8) new insights into the value of team interventions in blood management.

CONCLUSIONS

Much has changed since the previously published 2007 STS blood management guidelines and this document contains new and revised recommendations.

Prothrombin complex concentrate mitigates diffuse bleeding after cardiopulmonary bypass in a porcine model

Background

Extracorporeal circuit priming and intravascular volume expansion during cardiopulmonary bypass (CPB) may lead to dilutional coagulopathy and excessive diffuse postoperative bleeding. Prothrombin complex concentrate (PCC) containing clotting factors II (FII), VII (FVII), IX (FIX), and X (FX) could be of potential value in correcting dilutional coagulopathy and reducing blood loss.

Methods

Anaesthetized pigs underwent CPB with hypothermia for 2 h at 25°C followed by 1 h of normothermia. Approximately 1 h after CPB, animals randomly received either isotonic saline 1 ml kg⁻¹ or PCC 30 IU kg⁻¹ in a volume of 1 ml kg⁻¹. Diffuse coagulopathic bleeding was assessed as suture hole blood loss from a Gore-Tex patch placed over a full-thickness incision in the left carotid artery.

Results

After CPB, levels of FII, FVII, FIX, and FX declined from baseline by 32% to 48%, and PCC fully or partially reversed those deficits. Median suture hole blood loss after administration of saline placebo was 74 ml. PCC reduced suture hole bleeding by a median of 54 ml with a 95% confidence interval of 6–112 ml (P=0.026) compared with saline. PCC, but not saline, normalized skin bleeding time. Peak thrombin generation markedly decreased after CPB, but then returned in PCC-treated animals to a level higher than baseline by 28.7 nM (14.5–41.1 nM; P=0.031).

Conclusions

PCC was effective in correcting dilutional coagulopathy and reducing diffuse bleeding in an in vivo large-animal CPB model. Further research is warranted on PCC as a haemostatic agent in CPB.