Effect of clopidogrel on bleeding and transfusions after off-pump coronary artery bypass graft surgery: impact of discontinuation prior to surgery

Platelet Reactivity and Outcomes after Off-Pump Coronary Surgery in Acute Coronary Syndrome Patients

Ischemic and hemorrhagic complications are major determinants of survival in acute coronary syndrome (ACS) patients undergoing coronary surgery. We investigated the association of preoperative platelet reactivity to P2Y₁₂ antagonists with ischemic and hemorrhagic complications after Off-Pump Coronary Artery Bypass surgery (OPCAB) in ACS patients who received dual anti-platelet therapy (DAPT) within 5 days prior to surgery. This prospective, observational study with 177 patients compared the incidence of perioperative major bleeding and major adverse cardiac events (MACEs) in relation to the tertile distribution of the % inhibitory response to P2Y₁₂ antagonists, as measured by a thromboelastography platelet mapping assay. The incidences of perioperative major bleeding and MACEs were similar in relation to the tertile distribution of inhibitory response to P2Y₁₂ antagonists. The % inhibitory responses to P2Y₁₂ antagonists between patients who did or did not exhibit MACEs, and with or without major bleeding, were 58 ± 20% and 56 ± 20% (p = 0.578) and 57 ± 19% and 56 ± 21% (p = 0.923), respectively. In ACS patients who received DAPT close to OPCAB, the platelet inhibitory response to P2Y₁₂ antagonists was not associated with ischemic or hemorrhagic complications. OPCAB may obviate the need for routine platelet function testing for ACS patients requiring DAPT and surgical revascularization. Clinical Registration Number: NCT02184884.

Effect of anti-platelet therapy on peri-operative blood loss in patients undergoing off-pump coronary artery bypass grafting

Purpose:

The purpose of this study was to review the effect of the pre-operative use of clopidogrel and aspirin on peri-operative bleeding, blood product transfusion, and resource utilization after coronary artery bypass grafting (CABG).

Materials and Methods:

A total of 1200 patients who underwent off-pump CABG (OPCABG) between 2010 and 2012 were retrospectively studied. Patients were divided into three groups: group 1: discontinued aspirin and clopidogrel 6 days prior to surgery (n = 468), group 2: discontinued both drugs 3 to 5 days prior to surgery (n = 621), and group 3: discontinued both drugs 2 days prior to surgery (n = 111). The bleeding pattern and blood product transfusion were studied and compared between the groups. Patients having history of other drugs affecting the coagulation profile, other organ dysfunction, on-pump CABG, and the combined procedure were excluded from the study.

Results:

Group 2 patients had a higher rate of bleeding and a reduced mean value of hemoglobin (Hb) as compared to other groups. The same results were seen in blood and blood product transfusion. Patients of group 2 and group 3 were associated with higher blood loss in terms of drainage at 12 and 24 hours. Post-operatively, this was statistically significant. Re-exploration was statisitically significant in group 3 patients (9.01%) than in group 2 (2.58%) and group 1 (1.07%) patients.

Conclusion:

The pre-operative use of clopidogrel and aspirin in patients undergoing OPCABG showed limited clinical benefits; however, its use significantly increased the risk of bleeding and blood transfusion, thus increasing morbidity and resource utilization. Hence, clopidogrel and aspirin should be stopped at least 6 days prior to surgery.

The Association Between Clopidogrel and Gastrointestinal Bleeding After Primary Total Joint Arthroplasty

Background

Anticoagulation after total joint arthroplasty has been demonstrated to reduce venous thromboembolism. However, anticoagulation can lead to adverse bleeding events. The purpose of this study was to assess if an association exists between specific anticoagulation modalities, such as clopidogrel, and postoperative gastrointestinal (GI) bleeding.

Methods

A prospective cohort of Medicare patients undergoing total joint arthroplasty from 2017 to 2019 (3535 patients) was retrospectively reviewed. The baseline characteristics and anticoagulation methods were compared between the “GI bleed” cohort and the “non-GI bleed cohort.” Independent t-tests were conducted for continuous variables, while chi-squared analysis was conducted for dichotomous variables.

Results

Thirteen patients (0.42%) sustained a postoperative complication of a GI bleed. The mean age for patients sustaining a GI bleed was 69.23 years compared with 72.30 years for the non-GI bleed cohort (P = .11). Six patients who sustained a GI bleed (46%) were on an anticoagulation therapy other than aspirin, and this trended toward significance (P = .09). Five patients who sustained a GI bleed (38%) were on clopidogrel (P < .01). Seven percent of patients on clopidogrel sustained a postoperative GI bleed (P < .01). None of the patients who sustained a postoperative GI bleed had a history of peptic ulcer disease.

Conclusion

Patients on clopidogrel in the acute perioperative period demonstrated a strong association with the complication of postoperative GI bleeding. Arthroplasty surgeons should be aware of this association to educate and monitor patients on clopidogrel therapy and to work as part of interdisciplinary teams to assess the risks vs benefits of perioperative clopidogrel.

Platelet Quiescence in Patients With Acute Coronary Syndrome Undergoing Coronary Artery Bypass Graft Surgery

Background The optimal antiplatelet strategy for patients with acute coronary syndromes who require coronary artery bypass surgery remains unclear. While a more potent antiplatelet regimen will predispose to perioperative bleeding, it is hypothesized that through "platelet quiescence," ischemic protection conferred by such therapy may provide a net clinical benefit. Methods and Results We compared patients undergoing coronary artery bypass surgery who were treated with a more potent antiplatelet inhibition strategy with those with a less potent inhibition through a meta-analysis. The primary outcome was all-cause mortality after bypass surgery. The analysis identified 4 studies in which the antiplatelet regimen was randomized and 6 studies that were nonrandomized. Combining all studies, there was an overall higher mortality with weaker strategies compared with more potent strategies (odds ratio, 1.38; 95% CI, 1.03-1.85; P=0.03). Conclusions Our findings support the concept of platelet quiescence, in reducing mortality for patients with acute coronary syndrome requiring coronary artery bypass surgery. This suggests the routine up-front use of potent antiplatelet regimens in acute coronary syndrome, irrespective of likelihood of coronary artery bypass graft.

Hybrid coronary revascularization versus total arterial revascularization for the treatment of left main coronary artery disease

Background

Hybrid coronary revascularization (HCR) has a similar clinical outcome to coronary artery bypass grafting (CABG) in treating multivessel disease. However, the outcome of HCR in treating left main coronary artery (LM) disease is unclear. This study sought to compare the clinical outcome of HCR with total arterial revascularization (TAR) for treating LM disease.

Methods

Patients who underwent treatment for LM disease in our center between January 2009 and December 2019 were selected. Of these, 33 patients underwent HCR, and 70 patients underwent TAR. The primary efficacy outcome of this study was mid-term major adverse cardiac and cerebrovascular events (MACCE). The primary safety outcome was perioperative MACCE.

Results

The incidence of postoperative outcomes was comparable between the two groups after adjustment with inverse probability weighting (IPW) (P>0.05). The median follow-up time was 47 (interquartile range, 20 to 85) months. There was no significant difference in the incidence of all mid-term outcomes and the freedom of MACCE between the two groups after adjustment (P>0.05). The Cox proportional hazard model demonstrated that HCR was not a significant determinant for MACCE [hazard ratio (HR) =3.516, 95% confidence interval (CI): 0.835 to 14.813].

Conclusions

HCR may be safe and effective for the treatment of LM disease compared with TAR.

Elective spine surgery with continuation of clopidogrel anti-platelet therapy: Experiences from the community

PURPOSE

This retrospective study aimed to assess the feasibility of continuing clopidogrel therapy during the perioperative period in elective cervical and thoracolumbar surgery.

METHODS

After IRB approval, medical records of patients requiring one or two-level surgery over a two-year period (2015-2017) while receiving clopidogrel were reviewed for relevant outcomes. Over the same period, a control group of patients not receiving clopidogrel perioperatively was formed.

RESULT

In total, 136 patients were included: 37 clopidogrel and 99 control, with a mean age of 64.8 years. Between clopidogrel and control respectively, operative time was 86.7 min and 86.7 min (p = 0.620); blood loss was 127.0 cc and 117.5 cc (p = 0.480); drain output was 171.2 cc and 190.7 cc (p = 0.354); length of stay was 1.8 days and 1.5 days (p = 0.103). Two clopidogrel patients and 1 control patient had complications. Two clopidogrel patients and 1 control patient were readmitted within 30 days.

CONCLUSIONS

Remaining on clopidogrel therapy during elective spine surgery results in no difference in operative time, blood loss, drain output, length of stay, or readmission. Precaution should be taken in cervical procedures as the drain output in clopidogrel patients was increased and complications in this region can be severe.

Diagnostic and therapeutic medical devices for safer blood management in cardiac surgery: systematic reviews, observational studies and randomised controlled trials

Background

Anaemia, coagulopathic bleeding and transfusion are strongly associated with organ failure, sepsis and death following cardiac surgery.

Objective

To evaluate the clinical effectiveness and cost-effectiveness of medical devices used as diagnostic and therapeutic tools for the management of anaemia and bleeding in cardiac surgery.

Methods and results

Workstream 1 – in the COagulation and Platelet laboratory Testing in Cardiac surgery (COPTIC) study we demonstrated that risk assessment using baseline clinical factors predicted bleeding with a high degree of accuracy. The results from point-of-care (POC) platelet aggregometry or viscoelastometry tests or an expanded range of laboratory reference tests for coagulopathy did not improve predictive accuracy beyond that achieved with the clinical risk score alone. The routine use of POC tests was not cost-effective. A systematic review concluded that POC-based algorithms are not clinically effective. We developed two new clinical risk prediction scores for transfusion and bleeding that are available as e-calculators. Workstream 2 – in the PAtient-SPecific Oxygen monitoring to Reduce blood Transfusion during heart surgery (PASPORT) trial and a systematic review we demonstrated that personalised near-infrared spectroscopy-based algorithms for the optimisation of tissue oxygenation, or as indicators for red cell transfusion, were neither clinically effective nor cost-effective. Workstream 3 – in the REDWASH trial we failed to demonstrate a reduction in inflammation or organ injury in recipients of mechanically washed red cells compared with standard (unwashed) red cells.

Limitations

Existing studies evaluating the predictive accuracy or effectiveness of POC tests of coagulopathy or near-infrared spectroscopy were at high risk of bias. Interventions that alter red cell transfusion exposure, a common surrogate outcome in most trials, were not found to be clinically effective.

Conclusions

A systematic assessment of devices in clinical use as blood management adjuncts in cardiac surgery did not demonstrate clinical effectiveness or cost-effectiveness. The contribution of anaemia and coagulopathy to adverse clinical outcomes following cardiac surgery remains poorly understood. Further research to define the pathogenesis of these conditions may lead to more accurate diagnoses, more effective treatments and potentially improved clinical outcomes.

Study registration

Current Controlled Trials ISRCTN20778544 (COPTIC study) and PROSPERO CRD42016033831 (systematic review) (workstream 1); Current Controlled Trials ISRCTN23557269 (PASPORT trial) and PROSPERO CRD4201502769 (systematic review) (workstream 2); and Current Controlled Trials ISRCTN27076315 (REDWASH trial) (workstream 3).

Funding

This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full inProgramme Grants for Applied Research; Vol. 5, No. 17. See the NIHR Journals Library website for further project information.

Dual antiplatelet therapy and non-cardiac surgery: evolving issues and anesthetic implications

Dual antiplatelet therapy (DAPT) consisting of aspirin plus a P2Y₁₂ inhibitor (clopidogrel, prasugrel, or ticagrelor) is imperative for the treatment of acute coronary syndrome, particularly during the re-endothelialization period after percutaneous coronary intervention (PCI). When patients undergo surgery during this period, the consequences of stent thrombosis are far more serious than those of bleeding complications, except in cases of intracranial surgery. The recommendations for perioperative DAPT have changed with emerging evidence regarding the improved efficacy of non-first-generation drug (everolimus, zotarolimus)-eluting stents (DES). The mandatory interval of 1 year for elective surgery after DES implantation was shortened to 6 months (3 months if surgery cannot be further delayed). After this period, it is generally recommended that the P2Y₁₂ inhibitor be stopped for the amount of time necessary for platelet function recovery (clopidogrel 5-7 days, prasugrel 7-10 days, ticagrelor 3-5 days), and that aspirin be continued during the perioperative period. In emergent or urgent surgeries that cannot be delayed beyond the recommended period after PCI, proceeding to surgery with continued DAPT should be considered. For intracranial procedures or other selected surgeries in which increased bleeding risk may also be fatal, cessation of DAPT (possibly with continuation or minimized interruption [3-4 days] of aspirin) with bridge therapy using short-acting, reversible intravenous antiplatelet agents such as cangrelor (P2Y₁₂ inhibitor) or glycoprotein IIb/IIIa inhibitors (tirofiban, eptifibatide) may be contemplated. Such a critical decision should be individually tailored based on consensus among the anesthesiologist, cardiologist, surgeon, and patient to minimize both ischemic and bleeding risks.

Clopidogrel and hip fractures, is it safe? A systematic review and meta-analysis

Background

Femoral neck fractures in the elderly make up a large proportion of Orthopaedic surgical admissions each year. Operating on patients with clopidogrel poses a challenge because of the risk of bleeding and the difficulty deciding the optimal timing of surgery. The aim of this systematic review is to examine the published evidence to establish a set of guidelines for approaching neck of femur patients who are on clopidogrel.

Methods

All comparative studies with an intervention group and a control group were considered. Data on patient blood transfusion exposures, units transfused, haemoglobin concentration and drop in haemoglobin were extracted and pooled using the fixed effects model. Heterogeneity of the intervention effect was assessed with the I² statistic.

Results

A total of 4219 studies were identified. After removal of duplicates and after exclusion criteria were applied, there were 14 studies to be included. All 14 were case series with controls. There was no significant heterogeneity amongst the studies. Pooled odds ratio for transfusion exposures was 1.24 (95 % confidence interval 0.91 to 1.71) however this was not statistically significant (p = 0.14). No significant mean differences were found for other primary outcome measures.

Conclusions

On the available evidence, we recommend that these patients can be managed by normal protocols with early surgery. Operating early on patients on clopidogrel is safe and does not appear to confer any clinically significant bleeding risk. As reported in other studies, we believe clopidogrel, if possible, should not be withheld throughout the perioperative period due to increased risk of cardiovascular events associated with stopping clopidogrel. Care should be taken intraoperatively to minimise blood loss due to the increased potential for bleeding.

Trial registration

This systematic review and meta-analysis has been registered on Research Registry on July 16, 2015. The Review Registry Unique Identifying Number is: reviewregistry61.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-0988-9) contains supplementary material, which is available to authorized users.

Blood Conservation in Cardiac Surgery

Blood transfusion is the most common procedure in cardiac surgery. Increasing evidence exists that excess transfusions are harmful to patients. Transfusion reactions and complications, including infection, immune modulation, and lung injury, are known complications but underreported; hence, their significance is often disregarded. Furthermore, a number of randomized trials have shown that a restrictive transfusion strategy is equal to if not better than a liberal transfusion strategy. Despite the evidence for the use of restrictive transfusion triggers, its dissemination in the cardiac surgical community has met with resistance. In this review, we outline the risks of transfusion, compare restrictive and liberal transfusion strategies in cardiac surgery, and finally outline perioperative interventions to minimize transfusion in the cardiac surgical patient.

Bleeding Outcomes Associated with Coronary Artery Bypass Graft Surgery and Recent Clopidogrel Exposure

<p><b>Background:</b> Guidelines recommend discontinuing clopidogrel for at least 5 days before elective coronary artery bypass graft surgery (CABG) to limit blood transfusions and for at least 24 hours before urgent CABG to reduce major bleeding complications. Studies have produced conflicting results regarding whether recent exposure to clopidogrel increases bleeding, the need for intraoperative and postoperative blood products, postoperative complications, and hospital length of stay. We evaluated the effect of clopidogrel exposure on major bleeding at our institution within 5 days of CABG.</p><p><b>Methods:</b> We conducted a retrospective review of patients who underwent CABG at a tertiary academic medical center. The primary outcome was major bleeding, defined as transfusion of 4 units of packed red blood cells (PRBCs) and/or a need for reexploration. Secondary outcomes included non-life-threatening bleeding, defined as transfusion of 2 units but <4 units of PRBCs; postoperative complications; hospital length of stay; readmission within 30 days of the procedure; and hospital mortality. Major bleeding events were analyzed with a logistic regression model that adjusted for covariates of bleeding risk factors.</p><p><b>Results:</b> Of the 715 patients we reviewed, 169 patients received clopidogrel within 5 days before CABG, and 546 patients did not. A significantly higher incidence of major bleeding was observed in the clopidogrel group compared with the group not exposed to clopidogrel (32% versus 17%, <i>P</i> = .002). After adjusting for covariates, patients exposed to clopidogrel had significantly higher odds of major bleeding (odds ratio, 2.1; 95% confidence interval, 1.3-3.4; <i>P</i> = .003). The groups were similar with respect to postoperative complications, except for infection. The clopidogrel-exposed group had a significantly higher rate of leg site infections (3% versus 0.2%, <i>P</i> = .003).</p><p><b>Conclusions:</b> Clopidogrel exposure within 5 days of CABG is associated with an increased risk of major bleeding.</p>

Local use of ankaferd blood clotter in emergent beating heart coronary artery bypass grafting

Background:

Severe beeding which requiring massive blood transfusion after emergent beating heart surgery is shown to be 1–3%. Therefore, complications and side effects of transfusion can be seen. The aim of this study was to investigate the effectiveness of Ankaferd blood clotter (ABC) as a new topical herbal blood clotter to decrease mediastinal bleeding in emergent beating heart CABG patients who medicated with clopidogrel and acetyl salisilic acite (ASA) prior to CABG surgery.

Materials and Methods:

25 CABG patients received a high dose clopidogrel (600 mgr) and 300 mgr ASA have been included into the study (ABC group). 25 patients have also been included into the study for comparison (placebo group, PG). After the administration of protamine sulphate, a 10 ml of ABC solution has been sprayed to the surgical area including mediastinum and epicardial sac. We compared mediastinal drenaige, reoperation due to tamponade, and required blood and blood products in both groups.

Results:

The mean amount of bleeding after operation was 230 ml in ABC group, and 490 ml in CG (P=0.001). In ICU, bleeding in ABC group and CG was 410ml and 680ml, respectively (P=0.0022). The mean total bleeding from mediastinum was 530±280 mL and 990±440 mL In ABC and CG group, respectively (P=0.001). The amount of autotransfusion was as follows: 175 mL in ABC group, and 290 mL in CG (P=0.002). No patient needed the surgical revision in ABC group, but four patients (16%) from CG group because of cardiac tamponade. Seventeen patients from CG required blood transfusion due to low hematocrite level postoperatively. In CG, the mean hematocrite level was 17±2,3. Transfusion of fresh frozen plasma and platelets in ABC group and CG were as follows: 0.2 and 0 in ABC group, and 0.3and 0.4 in CG.

Conclusion:

Our study showed that the local use of 10 mL ABC reduces bleeding significantly. Therefore, transfusion requirements of PRBC, platelets, and total blood units in patients on clopidogrel and ASA undergoing emergent beating heart CABG. To provide cardiac tamponade because of excessive mediastinal bleeding and requirement of blood transfusion after emergent CABG patients who previously administered clopidogrel and ASA, we propose local use of ABC solution as a potent coagulant agent.

Impact of aspirin and clopidogrel interruption on platelet function in patients undergoing major vascular surgery

Aims

To investigate functional platelet recovery after preoperative withdrawal of aspirin and clopidogrel and platelet function 5 days after treatment resumption.

Methods/Results

We conducted an observational study, which prospectively included consecutive patients taking aspirin, taking clopidogrel, and untreated controls (15 patients in each group). The antiplatelet drugs were withdrawn five days before surgery (baseline) and were reintroduced two days after surgery. Platelet function was evaluated by optical aggregation in the presence of collagen, arachidonic acid (aspirin) and ADP (clopidogrel) and by VASP assay (clopidogrel). Platelet-leukocyte complex (PLC) level was quantified at each time-point. At baseline, platelet function was efficiently inhibited by aspirin and had recovered fully in most patients 5 days after drug withdrawal. PLC levels five days after aspirin reintroduction were similar to baseline (+4±10%; p = 0.16), in line with an effective platelet inhibition. Chronic clopidogrel treatment was associated with variable platelet inhibition and its withdrawal led to variable functional recovery. PLC levels were significantly increased five days after clopidogrel reintroduction (+10±15%; p = 0.02), compared to baseline.

Conclusions

Aspirin withdrawal 5 days before high-bleeding-risk procedures was associated with functional platelet recovery, and its reintroduction two days after surgery restored antiplaletet efficacy five days later. This was not the case of clopidogrel, and further work is therefore needed to define its optimal perioperative management.

Risk of bleeding and adverse outcomes predicted by thromboelastography platelet mapping in patients taking clopidogrel within 7 days of non-cardiac surgery

BACKGROUND

Patients often fail to stop clopidogrel appropriately before non-cardiac surgery. Thromboelastography platelet mapping (TEG-PM) can be used to measure the percentage adenosine 5'-diphosphate platelet receptor inhibition (ADP-PRI) by clopidogrel in these patients.

METHODS

This prospective case-control study investigated the risk of bleeding in patients who had taken clopidogrel within 7 days of scheduled operation. Patients underwent TEG-PM to stratify their bleeding risk. Low-risk (ADP-PRI below 30 per cent) and urgent priority high-risk (ADP-PRI 30 per cent or more) patients proceeded to surgery. The outcomes of these patients were compared with those of matched controls. Regression analysis, with bootstrapping validation, was used to identify independent risk factors for bleeding and an optimal cut-off value of ADP-PRI for cancellation of surgery.

RESULTS

From May 2008 to October 2013, 182 patients failed to discontinue clopidogrel. No correlation was observed between duration of clopidogrel omission and percentage ADP-PRI; 112 low-risk and 19 high-risk patients proceeded to surgery. High-risk patients had significantly greater intraoperative packed red blood cell (PRBC) transfusion in comparison with their matched controls, and a strong positive correlation between percentage ADP-PRI and units of intraoperative PRBCs transfused (r = 0·749, 95 per cent confidence interval (c.i.) 0·410 to 0·940; P < 0·001). Percentage ADP-PRI was the only independent risk factor for intraoperative PRBC transfusion (odds ratio 1·07, 95 per cent c.i. 1·02 to 1·13; P = 0·005).

CONCLUSION

An objective measure of platelet inhibition with TEG-PM, using an ADP-PRI cut-off of 34 per cent, can be used to prevent unnecessary cancellations, while minimizing patient risk.

The impact of clopidogrel therapy on postoperative bleeding after robotic-assisted coronary artery bypass surgery

OBJECTIVES

The purpose of this study was to determine whether patients undergoing robotic-assisted coronary artery bypass graft surgery (CABG) on clopidogrel had an increased risk of bleeding complications compared with those not on clopidogrel.

METHODS

From 2008 to 2011, 322 patients underwent robotic-assisted CABG either as an isolated procedure or as part of a hybrid coronary revascularization procedure (HCR). Patients were classified according to whether they received clopidogrel within 5 days of surgery or intraoperatively (n = 64) compared with those who never received or who had discontinued clopidogrel therapy >5 days before surgery (n = 258). A propensity analysis using 31 preoperative variables was used to control for confounding variables. In a subgroup analysis, patients undergoing one-stage HCR (clopidogrel load 600 mg in odds ratio (OR) prior to stenting) were compared with patients in the clopidogrel group who underwent two-stage HCR.

RESULTS

In the Clopidogrel group, the mean interval between surgery and last dose of clopidogrel was 2.1 ± 1.5 days. Compared with the No Clopidogrel group, the Clopidogrel group had greater 24-h chest tube drainage (1003 ± 572 vs 782 ± 530 ml, P = 0.004) and more blood transfusions (35.9%, 23 of 64 patients vs 20.9%, 54 of 258 patients, P = 0.01). On logistic regression analysis, there was greater 24-h chest tube drainage in the Clopidogrel group (+198 ml, P = 0.02) and a significantly higher incidence of blood transfusion (OR = 2.30, P = 0.01). In the subgroup analysis, patients undergoing one-stage HCR (n = 17) had greater 24-h chest tube drainage compared with patients undergoing two-stage HCR (1262 vs 909 ml, P = 0.03).

CONCLUSIONS

Patients undergoing robotic-assisted CABG on clopidogrel had more postoperative bleeding and a higher incidence of blood transfusion. Therefore, despite a less invasive approach, surgery should be delayed in these patients when possible.

Continuing clopidogrel during elective total hip and knee arthroplasty: assessment of bleeding risk and adverse outcomes

Limited research assessing risks of continued clopidogrel perioperatively in patients undergoing elective orthopedic procedures exists. Patients that underwent elective primary or revision total knee arthroplasty (TKA) or total hip arthroplasty (THA) from 2007 to 2012 while taking clopidogrel at the time of surgical evaluation were retrospectively identified. Patient demographics, last dose of clopidogrel, intraoperative blood loss, blood transfusion, and presence of 30-day adverse cardiac events (ACE) were collected. Of 142 patients meeting criteria, 24 (16.9%) patients remained on clopidogrel perioperatively. Patients that continued clopidogrel were more likely to receive a blood transfusion within 24 hours of surgery (31.8% vs. 7.7%; P=0.004) and during hospitalization (37.5% vs. 15.3%; P=0.02), but the incidence of 30-day ACE was not significantly different. Continuation of clopidogrel perioperatively for elective THA or TKA should be carefully considered.

Is continuation of antiplatelets until coronary artery bypass safe in Asians?

Background

Controversies have arisen about the risks of discontinuing antiplatelets prior to coronary artery bypass grafting.

Methods

We retrospectively studied the effects of different strategies of antiplatelet discontinuation prior to coronary artery bypass on perioperative bleeding and major adverse cardiovascular events in Asian patients in a single center in Singapore.

Results

402 patients were divided into 4 groups: group A had no antiplatelets before surgery; antiplatelets were stopped for 5–7 days in group B; 2–4 days in group C; and 0–1 day in group D. Compared to group B, group D had longer intensive care unit stays and more intraoperative transfusions of blood ( p = 0.006) and blood products ( p < 0.05). The 1-year major adverse cardiovascular event rate was higher in groups A and D ( p = 0.027). Stopping antiplatelets within 24 h of surgery was one of multiple independent predictors of intraoperative transfusion but not the 1-year major adverse cardiovascular event rate. Patients on aspirin alone had less intraoperative transfusion of platelets and postoperative minor bleeding than those on combined therapy.

Conclusion

Continuation of antiplatelets until 2 days before coronary artery bypass in Asian patients in our institution is unlikely to increase the risks of bleeding and perioperative transfusion. Taking antiplatelets within 24 h of surgery seems to be associated with a higher rate of 1-year major adverse cardiovascular events and bleeding, and an increased risk of blood product transfusion. Thirty-day and 1-year major adverse cardiovascular event rates were higher in patients without antiplatelet treatment.

The influence of hypothermia on transfusion requirement in patients who received clopidogrel in proximity to off-pump coronary bypass surgery

PURPOSE

Hypothermia adversely affects the coagulation that could be of clinical significance in patients receiving clopidogrel. We evaluated the influence of hypothermia on transfusion requirements in patients undergoing isolated off-pump coronary artery bypass surgery (OPCAB) who continued clopidogrel use within 5 days of surgery.

MATERIALS AND METHODS

Protocol-based, prospectively entered data of 369 patients were retrospectively reviewed. The time-weighted average of intraoperative temperatures and the temperature upon ICU admission (TWA-temp) was assessed. Patients were divided into normothermia (≥36°C, n=224) and hypothermia (<36°C, n=145) group. The transfusion requirement for perioperative blood loss was assessed and compared.

RESULTS

Patients with hypothermia were older and had lower body surface area (BSA) than patients with normothermia. Age and BSA adjusted transfusion requirement was significantly larger in the hypothermia group [patients requiring transfusion: 64% versus 48%, p=0.003; number of units: 0 (0-2) units versus 2 (0-3) units, p=0.002]. In multivariate analysis of predictors of perioperative multiple transfusion requirements, hypothermia was identified as an independent risk factor along with age, female gender, BSA, chronic kidney disease, and congestive heart failure.

CONCLUSION

Hypothermia was associated with increased transfusion requirement in patients undergoing OPCAB who received clopidogrel in proximity to surgery. Considering the high prevalence and the possibility of hypothermia being a modifiable risk factor, aggressive measures should be undertaken to maintain normothermia in those patients.

Does Dual Antiplatelet Therapy Affect Blood Loss and Transfusion Requirements in Robotic-Assisted Coronary Artery Surgery?

Objective

Patients who present for coronary surgery often receive preoperative dual antiplatelet therapy with aspirin and a thienopyridine derivative (clopidogrel or prasugrel), especially after a recent acute coronary syndrome. Studies have shown that patients on aspirin and clopidogrel are at increased risk for perioperative bleeding and related events. We sought to examine the impact of dual antiplatelet therapy on bleeding and transfusion requirements in patients undergoing robotic-assisted minimally invasive coronary artery bypass grafting.

Methods

From January 2010 to November 2011, a total of 110 patients underwent robotic-assisted off-pump coronary surgery at our institution. All patients underwent robotic-assisted harvest of the left internal mammary artery from the chest wall. Some patients then underwent direct coronary anastomosis to the left anterior descending coronary artery via a left minithoracotomy, whereas others had a complete robotic endoscopic procedure within the closed chest. The patients were divided into two groups for outcome analysis on the basis of preoperative antiplatelet therapy: group 1 (either aspirin alone or no antiplatelet agents at all; n = 53) and group 2 (aspirin plus clopidogrel or prasugrel; n = 57).

Results

Perioperative chest tube drainage was not significantly different between the patient groups, irrespective of the preoperative antiplatelet agents used. Transfusion requirements and other morbidities were also similar in both groups of patients.

Conclusions

Preoperative dual antiplatelet therapy does not result in significantly increased bleeding or perioperative transfusion requirements. If clinically indicated, it is reasonable to continue preoperative combination antiplatelet therapy in patients undergoing robotic-assisted coronary surgery.

Clinical outcomes after hybrid coronary revascularization versus off-pump coronary artery bypass: a prospective evaluation

OBJECTIVE

: Hybrid coronary revascularization is offered as an alternative strategy for patients with multivessel coronary artery disease (CAD). We present our experience and provide a comparative analysis to off-pump coronary artery bypass grafting (OPCAB).

METHODS

: Ninety-one patients with multivessel CAD underwent minimally invasive left internal mammary artery to left anterior descending grafting in combination with percutaneous coronary intervention of nonleft anterior descending targets (HYBRID). The primary end point of this study was major adverse cardiac and cerebrovascular events (MACCE), defined as death, stroke, and nonfatal myocardial infarction. MACCE in the HYBRID group were compared with 4175 contemporaneously performed OPCAB operations by logistic (30-day outcomes) and Cox proportional hazards (long-term survival) regression methods. Propensity scoring was used to adjust for potential selection bias.

RESULTS

: The 30-day MACCE (death/stroke/nonfatal myocardial infarction) rate was 1.1% for the HYBRID group (0%/0%/1.1%) and 3.0% for the OPCAB group (1.8%/1.1%/0.5%) (odds ratio = 0.47, P = 0.48). Angiographic left internal mammary artery evaluation was obtained in 95.6% of patients (87 of 91) revealing FitzGibbon A patency in 98.0% (96 of 98). The reintervention rate at 1 year for the HYBRID group was 5.5% (5 of 91) and was limited to repeat percutaneous coronary intervention. Three-year survival was statistically similar for the two groups (hazard ratio = 0.44, P = 0.18, see Kaplan-Meier figure).

CONCLUSIONS

: Hybrid coronary revascularization may be noninferior to OPCAB with respect to early MACCE and 3-year survival in the treatment of multivessel CAD.

The year in Cardiothoracic and Vascular Anesthesia: selected highlights from 2011

There have been rapid advances in oral anticoagulation. The oral factor Xa inhibitors rivaroxaban and apixaban and the oral direct thrombin inhibitor dabigatran recently have been rigorously evaluated. These novel anticoagulants will usher in a new paradigm for perioperative anticoagulation. Perioperative blood conservation in cardiac surgery recently has been highlighted in the updated guidelines by the Society of Cardiovascular Anesthesiologists and the Society of Thoracic Surgeons. These recommendations reflect a comprehensive evaluation of the recent evidence to optimize transfusion practice. Transcatheter mitral valve repair continues to mature. Transcatheter aortic valve implantation for aortic stenosis has entered the clinical mainstream, with randomized trials showing its superiority over medical management and its equivalency to surgical valve replacement in high-risk patients. This transformational technology represents a major leadership opportunity for the cardiac anesthesiologist. Minimally invasive valve surgery has shown effectiveness in high-risk patients. Radial access is equivalent to femoral access for percutaneous coronary intervention in acute coronary syndromes but significantly reduces the risk of local vascular complications. Recent trials have further clarified the roles of medical therapy, percutaneous coronary intervention, and coronary artery bypass surgery in patients with significant coronary artery disease and left ventricular dysfunction. The past year has witnessed major advances in cardiovascular practice with new drugs, new devices, and new guidelines. The coming year most likely will advance these achievements to enhance the care of patients.

Clopidogrel dilemma for orthopaedic surgeons

BACKGROUND

Patients medicated with clopidogrel who require orthopaedic surgery present a particular challenge. Whether in an emergency or elective situation the orthopaedic surgeon must balance the risks of ceasing clopidogrel versus the risk of increased bleeding that dual antiplatelet therapy generates.

METHOD

This paper reviews the current published evidence regarding the risks of continuing clopidogrel, the risks of discontinuing clopidogrel and associated considerations such as venous thromboprophylaxis.

RESULTS

Little good quality evidence exists in regard to perioperative clopidogrel for orthopaedic surgery. Available evidence across non-cardiac and cardiac surgery were assessed and presented in regards to current practices, blood loss for orthopaedic operations, risks when continuing clopidogrel, risks of stopping clopidogrel and also the consideration of venous thromboembolism.

CONCLUSIONS

The patients at greatest risk, when discontinuing clopidogrel therapy, are those with drug eluting stents who may be at risk of stent thrombosis. Where possible, efforts should be made to continue clopidogrel therapy through the perioperative period, taking precautions to minimize bleeding. If the risk of bleeding is too high, antiplatelet therapy must be reinstated as soon as considered reasonable after surgery. In addition, patients on clopidogrel who sustain a fall or other general trauma need to be carefully assessed because of the possibility of occult bleeding, such as into the retroperitoneal space. Until more definitive evidence becomes available, this review aims to provide a guide for the orthopaedic surgeon in dealing with the difficult dilemma of the patient on clopidogrel therapy, recommending that orthopaedic surgeons take a team approach to assess the individual risks for all patients and consider continuation of clopidogrel therapy perioperatively where possible.

Reversal of the anti-platelet effects of aspirin and clopidogrel

BACKGROUND

Guidelines recommend stopping aspirin and clopidogrel 7 to 10 days before surgery to allow time for replacement of permanently inhibited platelets by newly released uninhibited platelets.

OBJECTIVES

The purpose of the present study was to determine the rate of offset of the anti-platelet effects of aspirin and clopidogrel after stopping treatment and the proportion of untreated donor platelets that are required to reverse their anti-platelet effects.

METHODS

Cohort 1 consisted of 15 healthy subjects who received aspirin 81 mg day(-1) or clopidogrel 75 mg day(-1) for 7 days and underwent serial blood sampling until platelet function testing results normalized. Cohort 2 consisted of 36 healthy subjects who received aspirin 325 mg day(-1), clopidogrel 75 mg day(-1), aspirin 81 mg day(-1) plus clopidogrel 75 mg day(-1) or no treatment for 7 days and underwent a single blood sampling.

RESULTS

In cohort 1, arachidonic acid (AA)-induced light transmission aggregation (LTA) returned to baseline levels in all subjects within 4 days of stopping aspirin, coinciding with the partial recovery of plasma thromboxane B(2) concentrations. ADP-induced LTA did not return to baseline levels until 10 days after stopping clopidogrel. In cohort 2, AA-induced LTA in patient treated with aspirin reached control levels after mixing with 30% untreated donor platelets whereas ADP-induced LTA in patients treated with clopidogrel reached control levels only after the addition of 90% or more donor platelets.

CONCLUSIONS

Platelet aggregation recovers within 4 days of stopping aspirin but clopidogrel must be stopped for 10 days to achieve a normal aggregatory response.

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.

Impact of clopidogrel on bleeding complications and survival in off-pump coronary artery bypass grafting

This study investigated the impact of preoperative clopidogrel on bleeding complications and survival during and after off-pump coronary artery bypass grafting (OPCABG) and assessed the possible role of the antifibrinolytic agent aprotinin for attenuating blood loss after clopidogrel exposure. Prospectively collected data of 753 consecutive adult patients undergoing OPCABG were retrospectively reviewed; 139 (18.5%) patients received clopidogrel preoperatively. Statistical methods used were student paired t-test, Mann-Whitney U, Kruskal-Wallis, chi-square analysis and Kaplan-Meier with log-rank analysis. Clopidogrel was associated with a significant increase in perioperative blood loss (P = 0.003) and more excessive postoperative haemorrhage (P = 0.04). Overall transfusion rates (P = 0.02) and the amount of administered blood products (P = 0.01) were also higher after clopidogrel exposure. Intraoperative aprotinin reduced postoperative bleeding significantly in patients administered clopidogrel [18.7% after 24 h (P = 0.006) and 15.2% after 48 h (P = 0.03)] and attenuated excessive postoperative haemorrhaging. Five-year survival was markedly improved in clopidogrel-treated patients. Preoperative clopidogrel exposure does increase perioperative blood loss and blood transfusion requirements in patients undergoing OPCABG but has an otherwise excellent safety profile with a 94% 5-year survival rate. Aprotinin attenuated this blood loss. Based on these results a recommendation to discontinue clopidogrel prior to coronary artery bypass grafting cannot be maintained, if OPCABG strategies are considered.

Preoperative aspirin resistance does not increase myocardial injury during off-pump coronary artery bypass surgery

We performed a prospective cohort trial on 220 patients undergoing elective off-pump coronary artery bypass surgery and taking aspirin to evaluate the effect of aspirin resistance on myocardial injury. The patients were divided into aspirin responders and aspirin non-responders by the value of the aspirin reaction units obtained preoperatively using the VerifyNow™ Aspirin Assay. The serum levels of troponin I were measured before surgery and 1, 6, 24, 48 and 72 hr after surgery. In-hospital major adverse cardiac and cerebrovascular events, graft occlusion, the postoperative blood loss and reexploration for bleeding were recorded. Of the 220 patients, 181 aspirin responders (82.3%) and 39 aspirin non-responders (17.7%) were defined. There were no significant differences in troponin I levels (ng/mL) between aspirin responders and aspirin non-responders: preoperative (0.04 ± 0.08 vs 0.03 ± 0.06; P = 0.56), postoperative 1 hr (0.72 ± 0.87 vs 0.86 ± 1.10; P = 0.54), 6 hr (2.92 ± 8.76 vs 1.50 ± 2.40; P = 0.94), 24 hr (4.16 ± 13.44 vs 1.25 ± 1.95; P = 0.52), 48 hr (2.15 ± 7.06 vs 0.65 ± 0.95; P = 0.64) and 72 hr (1.20 ± 4.63 vs 0.38 ± 0.56; P = 0.47). Moreover, no significant differences were observed with regard to in-hospital outcomes. In conclusion, preoperative aspirin resistance does not increase myocardial injury in patients undergoing off-pump coronary artery bypass surgery. Postoperative dual antiplatelet therapy might have protected aspirin resistant patients.

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.

Evaluation of antiplatelet effects of a modified protocol by platelet aggregation in patients undergoing "one-stop" hybrid coronary revascularization

"One-stop" hybrid coronary revascularization has emerged to be a reliable and attractive alternative for selected patients with multivessel coronary artery disease. However, the optimal antiplatelet regimen of the one-stop hybrid procedure still remains controversial. We modified the antiplatelet protocol in order to reduce the risk of perioperative bleeding and maximally inhibit platelet activity. This study sought to investigate whether the inhibition of platelet activity by this modified antiplatelet protocol is comparable with the conventional protocol widely used and recommended in percutaneous coronary interventions (PCI). Twenty three patients undergoing one-stop hybrid procedure and 20 patients undergoing conventional PCI were enrolled in this prospective study. The modified antiplatelet protocol included perioperative use of aspirin; clopidogrel was administered immediately before PCI with a 300 mg loading dose, followed by a maintenance dose of 75 mg/day for 12 months. Blood samples were obtained before the operation and 2 hours, day 1 and day 3 after operation. Platelet aggregation was induced with: 1) arachidonic acid (AA) (final concentration 0.5 mmol/L) to assess the efficacy of aspirin; 2) adenosine diphosphate (ADP) (final concentration 10 micromol/L) to assess the specific efficacy of clopidogrel. Platelet counts were statistically lower in the hybrid group than in the PCI control group (p = 0.0018) on day 1 after operation. AA-induced platelet aggregation increased significantly in comparison with the preoperative baseline values (p = 0.0079) and the PCI control group (p = 0.0023) on day 1 after operation. ADP-induced platelet aggregation gradually decreased in the hybrid group, and achieved similar platelet inhibition with the PCI group on 2 hours and day 1 after operation. No major adverse clinical events such as death, perioperative myocardial infarction, stent thrombosis or reoperation for bleeding occurred in both groups within 30 days after procedure. These results demonstrate that our modified antiplatelet therapy can sufficiently inhibit platelet activity similarly as the conventional protocol for PCI early after operation. Thus, this modified protocol, with continuous use of aspirin and intraoperative administration of loading dose clopidogrel, might be a safe and effective antiplatelet strategy for the one-stop hybrid coronary revascularization.