The effect of preoperative clopidogrel on bleeding after coronary artery bypass surgery

Safety of Continued Clopidogrel Use in the Preoperative Course of Gastrointestinal Surgery: A Retrospective Cohort Study

OBJECTIVE

Our study aimed to estimate postoperative bleeding risk in older adults taking clopidogrel before gastrointestinal (GI) surgery, to aid surgeons in decisions regarding clopigogrel cessation.

SUMMARY BACKGROUND DATA

Balancing risks of postoperative bleeding associated with continued clopidogrel use and those associated with cessation is difficult for GI surgeons.

METHODS

Using 100% Texas Medicare Claims Data from 2006 to 2011, we identified patients undergoing emergent GI surgery. We propensity score matched patients on clopidogrel before surgery to patients not on clopidogrel. Using conditional logistic regression, we compared risks of bleeding events at 1-month postdischarge between groups, adjusting for bleeding risk factors.

RESULTS

In total, 1240 patients undergoing emergent GI surgery while treated with clopidogrel were matched to emergency GI surgery patients not treated with clopidogrel. The only significant preoperative differences between groups were higher percent of clopidogrel-treated patients with congestive heart failure, cholecystectomy, and lower percent of clopidogrel-treated patients with colectomy. Mean age was 76.91 (±7.06) and 76.70 (±7.05) years (P = 0.47), and 63.84% and 59.41% of operations were cholecystectomy, in the clopidogrel and nonclopidogrel groups (P = 0.18). In multivariable analyses adjusting for Elixhauser index, hyperlipidemia, confounding drugs, and surgery type, odds ratio for bleeding within 30 days of discharge in those exposed to clopidogrel compared with those not exposed was 1.60 (95% confidence interval, 1.08-2.38), with raw rates of bleeding 6.85% and 4.84%.

CONCLUSIONS

Clopidogrel use in older adults through the preoperative period of GI surgery does not significantly increase bleeding events in the month after surgery.

Use of adenosine diphosphate receptor inhibitor prior to left ventricular assist device implantation is not associated with increased bleeding

Current guidelines recommend adenosine diphosphate receptor inhibitors (ADPRi) be discontinued 5-7 days prior to cardiac surgery due to increased bleeding events, rates of re-exploration, and transfusions. However, the risks of left ventricular assist device (LVAD) implantation in patients taking an ADPRi have not previously been studied. We retrospectively identified 134 eligible patients with ischemic cardiomyopathy that underwent LVAD implantation between July 2009 and August 2013. The cohorts received an ADPRi ≤5 days of surgery (n = 25) versus >5 days prior or not at all (n = 109). Subgroup analyses adjusted for differences in frequency of redo sternotomy between cohorts, excluded patients that received an ADPRi >1 year prior to surgery, and excluded patients with a redo sternotomy. The ADPRi and control groups did not have significant differences in the primary outcomes, intraoperative PRBC units transfused (3.0 vs. 4.0, p = 0.12) or chest tube output within 24 h of surgery (1.66 L vs. 1.80 L, p = 0.61). After adjusting for differences in frequency of redo sternotomy (ADPRi vs. control, 12 vs. 52%, p ≤ 0.001), no significant difference in PRBC units transfused (3.1 vs. 3.5, p = 0.59) or chest tube output (2.04 L vs. 2.04 L, p = 0.98) was seen. No significant difference in 30-day mortality (8.0 vs. 11.0%, p = 0.63), 90-day mortality (16.4 vs. 23.3%, p = 0.42), or length of stay (29.0 vs. 28.0, p = 0.61) was seen. In this single-center experience, use of an ADPRi ≤5 days prior to LVAD implantation was not associated with increased bleeding, length of stay, or mortality.

Stopping antiplatelet medication before coronary artery bypass graft surgery: is there an optimal timing to minimize bleeding?

OBJECTIVES

As the indication for antiplatelet medication expands, patients may be exposed to an increased risk of excessive blood loss when cardiac surgery is required. The optimal timing to stop acetylsalicylic acid (ASA) or ASA combined with clopidogrel (ASA+Clo) before surgery is the subject of controversy.

METHODS

A total of 1065 patients were selected from a prospective randomized study on the effect of a fibrin sealant application in coronary artery bypass graft surgery [Fibrin sealant Induced Blood Exposure Reduction study;

REGISTRATION NUMBER

NTR1386 (http://www.trialregister.nl)], and divided into three groups according to the use of antiplatelet medication within 10 days prior to surgery: (i) ASA only (n = 662), (ii) ASA+Clo (n = 290) or (iii) no antiplatelet medication (n = 113). To investigate if an optimal stop day could be established, we fitted a series of multiple linear regression models, one for each preoperative day (running from Day -10 up to -1). The specific day corresponding to the best fitting model (highest adjusted R(2), with blood loss in the first 48 h postoperatively as the dependent variable) was considered as the best estimate for the optimal stop day. Bootstrap analysis (1000 times) was performed to calculate the corresponding confidence interval. Furthermore, major adverse cardiovascular and cerebral events (MACCE) were evaluated.

RESULTS

We could not estimate an optimal stop day for patients using ASA or ASA+Clo prior to their operation. Last use of ASA on Day -2 or earlier significantly decreased the percentage of patients receiving platelet transfusions compared with continuation until surgery (7 vs 13% for Day -1, P = 0.007). In patients using ASA+Clo, this percentage was reduced from 41 to 10 (P < 0.001). There was no association between stop day and the occurrence of MACCE.

CONCLUSIONS

There is no clinically relevant effect on blood loss indicating an optimal stop day for ASA alone or in combination with Clo. Last use on Day -2 resulted in the reduction of percentage of patients receiving platelet transfusions, especially in the ASA+Clo group.

Should clopidogrel be discontinued before laparoscopic cholecystectomy?

BACKGROUND

The perioperative management of clopidogrel remains an area of controversy.

METHODS

An institutional review board-approved retrospective review of patients undergoing a laparoscopic cholecystectomy while on clopidogrel from 2008 to 2012 was performed. These patients were then matched with a nonclopidogrel cohort based on American Society of Anesthesiologists score and emergent or elective surgery. Intraoperative estimated blood loss, operative time, length of stay, and 30-day morbidity were compared.

RESULTS

Thirty-six clopidogrel and 36 control patient records were analyzed. There were no significant differences in age, body mass index, sex, or incidence of coronary artery disease, diabetes, hyperlipidemia, and congestive heart failure. Estimated blood loss averaged 50 mL in the clopidogrel group and 47 mL in the control group (P = nonsignificant). There were no significant differences in operative time, 30-day morbidity, or length of stay between the 2 groups.

CONCLUSIONS

Laparoscopic cholecystectomy performed on patients maintained on clopidogrel during the perioperative period did not produce an increase in blood loss, operative time, 30-day morbidity, or length of stay.

Temporary adjunctive cilostazol vs clopidogrel loading for ST-segment elevation acute myocardial infarction

BACKGROUND

Clopidogrel loading is a standard method to achieve rapid platelet inhibition and prevent thrombotic events. At the current time, little information is available to determine the effect of adjunctive cilostazol compared with clopidogrel loading.

METHODS

We retrospectively analyzed 212 patients undergoing primary percutaneous coronary intervention with drug-eluting stents for ST-segment elevation acute myocardial infarction. All patients were administered aspirin (100 mg once a day) and clopidogrel (75 mg once a day). The patients were divided into two groups according to the presence (loading group, n = 100) or absence (cilostazol group, n = 112) of clopidogrel loading (300 mg). Patients in the cilostazol group were administered adjunctive cilostazol (100 mg twice a day) in place of clopidogrel loading. Patient characteristics, medications, and 30-day clinical outcomes were examined.

RESULTS

The mean duration of cilostazol administration in the cilostazol group was 6.2 ± 4.9 days from the time of primary coronary intervention. No significant difference was observed in major adverse cardiac events (cardiac death, definite stent thrombosis, and non-fatal myocardial infarction) between the loading group and the cilostazol group (9/100; 9.0 vs. 8/112; 7.1%, p = 0.62). Definite stent thrombosis was observed for two patients in the loading group and one patient in the cilostazol group. The occurrence ratio of bleeding events did not differ significantly between the two groups (9.0 vs. 5.4%, p = 0.30).

CONCLUSION

There was no significant difference in the incidence of major adverse cardiac events between temporary adjunctive cilostazol treatment and clopidogrel loading in ST-segment elevation acute myocardial infarction patients. Our findings suggest one potential of cilostazol.

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.

Clopidogrel Within Few Hours of Coronary Artery Bypass Grafting Does Significantly Increase the Risk of Bleeding

Background

Postoperative bleeding after coronary artery surgery is partly related to platelet dysfunction. The aim of this study was to evaluate the effects of a single loading dose of clopidogrel (300 mg) before coronary angiography on bleeding and use of blood and blood products after emergency coronary artery bypass surgery (CABG).

Methods

This is a nonrandomized observational prospective study between January, 2006 till December 2009, at a university hospital, we compare the results of a cohort of 65 patients who received 300 mg clopidogrel during coronary angiography that was followed by emergency CABG (group A or study group) to a cohort of 206 patients who underwent elective coronary artery bypass surgery during the same period by the same surgeons in whom clopidogrel was stopped 7 days before surgery (Group B or control group). Emergency surgery was done because of critical coronary anatomy or because of ongoing chest pain. All patients in the two groups were kept on 100 mg of aspirin until the day of surgery. Outcome data used to compare the two groups, Chest tube drainage in first 12 hours (12 h), need for re-exploration and use of blood and blood product transfusion were prospectively collected.

Results

Postoperative bleeding, reoperation rates for bleeding and use of blood products are significantly more in those who received a loading dose of clopedogril within few hours of CABG (group A) compared to those who stopped clopedogril for a week before CABG.

Conclusions

Preoperative 300 mg of clopidogrel is associated with significant increase in post operative bleeding, need for surgical exploration and use of blood and blood product transfusion after CABG.

Prevention of VTE in nonorthopedic surgical patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

VTE is a common cause of preventable death in surgical patients.

METHODS

We developed recommendations for thromboprophylaxis in nonorthopedic surgical patients by using systematic methods as described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines. Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

We describe several alternatives for stratifying the risk of VTE in general and abdominal-pelvic surgical patients. When the risk for VTE is very low (< 0.5%), we recommend that no specific pharmacologic (Grade 1B) or mechanical (Grade 2C) prophylaxis be used other than early ambulation. For patients at low risk for VTE (∼1.5%), we suggest mechanical prophylaxis, preferably with intermittent pneumatic compression (IPC), over no prophylaxis (Grade 2C). For patients at moderate risk for VTE (∼3%) who are not at high risk for major bleeding complications, we suggest low-molecular-weight heparin (LMWH) (Grade 2B), low-dose unfractionated heparin (Grade 2B), or mechanical prophylaxis with IPC (Grade 2C) over no prophylaxis. For patients at high risk for VTE (∼6%) who are not at high risk for major bleeding complications, we recommend pharmacologic prophylaxis with LMWH (Grade 1B) or low-dose unfractionated heparin (Grade 1B) over no prophylaxis. In these patients, we suggest adding mechanical prophylaxis with elastic stockings or IPC to pharmacologic prophylaxis (Grade 2C). For patients at high risk for VTE undergoing abdominal or pelvic surgery for cancer, we recommend extended-duration, postoperative, pharmacologic prophylaxis (4 weeks) with LMWH over limited-duration prophylaxis (Grade 1B). For patients at moderate to high risk for VTE who are at high risk for major bleeding complications or those in whom the consequences of bleeding are believed to be particularly severe, we suggest use of mechanical prophylaxis, preferably with IPC, over no prophylaxis until the risk of bleeding diminishes and pharmacologic prophylaxis may be initiated (Grade 2C). For patients in all risk groups, we suggest that an inferior vena cava filter not be used for primary VTE prevention (Grade 2C) and that surveillance with venous compression ultrasonography should not be performed (Grade 2C). We developed similar recommendations for other nonorthopedic surgical populations.

CONCLUSIONS

Optimal thromboprophylaxis in nonorthopedic surgical patients will consider the risks of VTE and bleeding complications as well as the values and preferences of individual patients.

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.

Cushing's surgery: Role of the anesthesiologist

Cushing's syndrome is a clinical situation, caused by excessive glucocorticoid level, resulting in several features such as central obesity, supraclavicular fat, "moon face," "buffalo hump," hyperglycemia, metabolic alkalosis, hypokalemia, poor wound healing, easy bruising, hypertension, proximal muscle weakness, thin extremities, skin thinning, menstrual irregularities, and purple striae. In the perioperative period, the anesthesiologist must deal with difficult ventilation and intubation, hemodynamic disturbances, volume overload and hypokalemia, glucose intolerance, and diabetes, maintaining the blood cortisol level and preventing the glucocorticoid deficiency. This syndrome is quite rare and its features make these patients very difficult to the anesthesiologist.

Perioperative management of antiplatelet-drugs in cardiac surgery

The management of coronary patients scheduled for a coronary artery bypass grafting (CABG), who are receiving one or more antiplatelet drugs, is plenty of controversies. It has been shown that withdrawal of antiplatelet drugs is associated with an increased risk of a thrombotic event, but surgery under an altered platelet function also means an increased risk of bleeding in the perioperative period. Because of the conflict recommendations, this review article tries to evaluate the outcome of different perioperative antiplatelet protocols in patients with coronary artery disease undergoing CABG.

Temporal trends and practice variations in clopidogrel loading doses in patients with non-ST-segment elevation myocardial infarction, from the National Cardiovascular Data Registry

BACKGROUND

A higher loading dose of clopidogrel achieves a more rapid and consistent degree of platelet inhibition than standard dosing, although the clinical benefit of higher doses has not been clearly established. The use of the different doses in clinical practice is not known. We evaluated the patient, procedural, and hospital characteristics associated clopidogrel loading doses given to patients with non-ST-segment elevation myocardial infarction (NSTEMI).

METHODS

The National Cardiovascular Data Registry ACTION Get With the Guidelines Registry was queried for patients with NSTEMI admitted from 2007 to 2008. Demographic, clinical, and procedural information were collected on standardized data forms. Patients were categorized according to the clopidogrel loading dose received. Temporal trends in the use of different doses were evaluated in quarterly time intervals.

RESULTS

Between January 1, 2007, and December 31, 2008, the use of a 600-mg clopidogrel loading dose increased steadily from 36.4% to 45.5%, whereas the use of 300 mg decreased slightly from 40.1% to 37.1%. Patients loaded with clopidogrel before cardiac catheterization were more likely to receive 300 mg, whereas those receiving a loading dose at the time of catheterization more often received 600 mg. The temporal increase in the use of 600 mg clopidogrel loading doses was not explained by temporal changes in periprocedural loading, use of early invasive management of patients with NSTEMI, or use of antithrombotics or glycoprotein 2b/3a inhibitors.

CONCLUSIONS

Higher loading dose clopidogrel increased between 2007 and 2008. Higher-dose clopidogrel was more frequently used in lower-risk patients undergoing an early invasive strategy and receiving periprocedural loading.

(R)-[1-(2-Chlorophenyl)-2-methoxy-2-oxoethyl][2-(thiophen-2-yl)ethyl]ammonium (+)-camphor-10-sulfonate acetone monosolvate

The title compound, C₁₅H₁₇ClNO₂S⁺·C₁₀H₁₅O₄S⁻·C₃H₆O, was synthesized by N-alkyl­ation of α-amino-(2-chloro­phen­yl)acetate with 2-thienylethyl p-toluene­sulfonate, followed by reaction with (+)-camphor-10-sulfonic acid. In the crystal, the cations and anions are linked through N—H⋯O hydrogen bonds. The thio­phene ring of the cation was found to be disordered over two sites, with refined occupancies of 0.798 (4) and 0.202 (4).

Perioperative Clopidogrel is Seven Days Enough?

Despite the prevalence of surgical candidates on clopidogrel, no definitive guidelines exist for stopping the drug preoperatively. A 7 day off-clopidogrel period is commonly considered safe with regards to bleeding complications. We sought to put the 7-day window to the test with regards to major bleeding events requiring either blood transfusions or return trips to the operating room. We collected data for patients taking clopidogrel in the perioperative period between 2005 and 2007 (n = 170). This data was then compared with the data of all of the patients undergoing surgery at our institution for the same time period (n = 34,480). Patients taking clopidogrel experienced a significantly higher rate of return trips to the operating room (6.5%) compared with nonclopidogrel patients (0.015%). Interestingly, we found no significant difference between those stopping clopidogrel more than 7 days preoperatively and those that did not (5% and 7.5%, respectively). There did not seem to be a significant difference in blood transfusion rates between the two clopidogrel groups. Patients on perioperative clopidogrel require reoperations for bleeding at a significantly higher rate compared with patients not taking clopidogrel. Discontinuing clopidogrel 7 days before surgery is not enough to negate this difference and these patients still experience a drastically higher rate of reoperations for bleeding.

"How I do it: utilization of high-pressure sealants in aortic reconstruction"

BACKGROUND

Suture-line hemostasis, reinforcement of friable tissue, and adhesion prevention are key concerns for patients undergoing cardiac surgery for aortic reconstruction. Failure to secure hemostasis at anastomotic junctures and reinforce fragile tissue may lead to increased blood loss, additional blood product requirements, increased operative time, and, in extreme cases, reoperation. Patients with aortic pathology may also be at higher risk for reoperation, and adhesion formation from prior surgery is an added risk at resternotomy. The advent of high-pressure sealants has been of benefit in helping to alleviate these perioperative challenges.

METHODS

The author utilizes two high-pressure sealants for aortic reconstructive procedures. The first is made of two polymers of polyethylene glycol (PEG) [Coseal, Baxter Healthcare, Corporation], and is used to secure anastomotic suture-line hemostasis and for adhesion prevention. The second is a bovine serum albumin-glutaraldehyde (BSAG) glue [BioGlue, CryroLife, Inc.], used for the repair of dissected aortic tissue and in reinforcing ("tanning") fragile aortic tissues. The techniques for application in select aortic reconstruction procedures are described.

RESULTS

To substantiate the hemostatic clinical benefit observed by the author, 60 consecutive major thoracic aortic operations in 57 patients in whom PEG sealant was used were retrospectively reviewed. Although comparisons with other agents were not performed for this descriptive report, bleeding results were very favorable for these types of operations. The strong clinical impression is that topical hemostatic application of PEG sealant to anastomotic suture lines is helpful in preventing bleeding.

CONCLUSION

In major aortic reconstructive procedures the need for anastomotic sealing performance, reinforcement of friable tissues, and adhesion prevention should not be underrated. High-pressure surgical sealants represent an important surgical adjunct, and the author has found the use of both PEG sealant and BSAG glue advantageous in aortic reconstruction and repair.

Evidence for using clopidogrel alone or in addition to aspirin in post coronary artery bypass surgery patients

Clopidogrel is recommended with aspirin for patients who undergo coronary artery bypass grafting (CABG) after non-ST elevation myocardial infarctions. Cardiothoracic surgeons widely use clopidogrel in addition to aspirin for post-CABG patients, including those with stable coronary artery disease. The aim of this study was to systematically review the published research to determine whether clopidogrel use after CABG is based on good trial data. Studies reporting safety and/or efficacy data for clopidogrel use with or without aspirin after on- or off-pump CABG were included. Fourteen studies met the inclusion criteria, of which 11 were reported trials and 3 are ongoing trials. Subgroup retrospective analyses of previously reported large trials of patients presenting with acute coronary syndromes (n = 1) or patients with stable coronary artery disease (n = 3) did not show a clear clinical benefit of clopidogrel when given in addition to aspirin after CABG. In contrast, there was a trend toward increased major and minor bleeding after the use of clopidogrel plus aspirin. Two small prospective trials providing data on surrogate end points and 5 small trials involving off-pump CABG patients were not of good quality to draw meaningful conclusions. In conclusion, summarized data based on subgroup analyses, surrogate end points, and observational cohort studies fail to demonstrate a clear beneficial effect of clopidogrel alone or in combination with aspirin on clinical outcomes after CABG.

Unmet needs in oral antiplatelet therapy with ADP receptor blocking agents

Antiplatelet agents like aspirin and clopidogrel are treatment cornerstones for acute coronary syndromes (ACS). Drawbacks of dual therapy with these agents include slow onset and offset of effect and wide response variability. Clopidogrel may provide little benefit if administered too close to percutaneous coronary intervention (PCI) and increase major bleeding risk if given too close to coronary artery bypass grafting (CABG) or other surgery. It may not provide sufficient antiplatelet coverage prior to CABG if stopped too long before intervention and leave patients without antiplatelet coverage due to hyporesponsiveness. Prasugrel has made steps towards addressing these limitations by exhibiting more efficient metabolism, more rapid onset of effect, and greater and more consistent platelet inhibition than clopidogrel. The TRITON-TIMI38 trial in ACS patients undergoing PCI showed prasugrel produced greater ischemic event protection than clopidogrel but significantly increased major bleeding risk. AZD6140, the first reversible oral P2Y(12) inhibitor, provides more rapid onset of effect and greater and more consistent platelet inhibition than clopidogrel. In DISPERSE2, a phase II trial in ACS patients, AZD6140 did not increase bleeding risk, reduced bleeding risk among CABG patients, and produced numerical reductions in myocardial infarction risk. AZD6140 is being compared with clopidogrel in PLATO, a phase III trial in approximately 18000 ACS patients.

Potential unrecognised costs of clopidogrel pretreatment in acute coronary syndrome

OBJECTIVE

To examine adherence in clinical practice to the American College of Cardiology/American Heart Association (ACC/AHA) guideline recommendations of observing a 5-day waiting period after clopidogrel administration before undergoing coronary artery bypass graft (CABG) surgery and to examine the costs of waiting.

METHODS

This retrospective study used a nationwide inpatient database (Solucient ACTracker) to identify patients who were admitted for acute coronary syndrome (ACS), and who had same-stay CABG. Cost of additional days of stay was estimated using regression analysis.

RESULTS

The recommended 5-day waiting was adhered to in 16.9% (n=3,809) of patients. The percentage of patients with ACS undergoing CABG surgery on day 0 was 14.6%. Adherence to the waiting was higher for teaching and rural hospitals; and in female and elderly patients and urgent admissions.

CONCLUSIONS

The recommended 5-day waiting for CABG surgery after clopidogrel treatment is poorly adhered to in clinical practice. This study was unable to determine specific reasons for the low adherence; however, there may be a compromise between the clinically urgent need for revascularisation and increased risk of bleeding, as well as economic costs associated with waiting. The cost of an additional hospital day in this group of patients was approximately £1,400 per day or £7,000 for 5 days. Thus, a full 5-day wait would have a significant economic impact on hospital costs.

Clopidogrel and Bleeding after General Surgery Procedures

Although many studies in the cardiothoracic literature exist about the relationship between clopidogrel and postoperative bleeding, there is scarce data in the general surgery literature. We assessed whether there are increased bleeding complications, morbidity, mortality, and resource utilization in patients who are on clopidogrel (Plavix®) within 1 week before undergoing a general surgery procedure. Fifty consecutive patient charts were retrospectively reviewed after identifying patients who had pharmacy orders for clopidogrel and who underwent a general surgery procedure between 2003 and 2007. Patients who took clopidogrel within 6 days before surgery (group I, n = 28) were compared with patients who stopped clopidogrel for 7 days or more (group II, n = 22). A larger percentage of patients who took their last dose of clopidogrel within 1 week of surgery (21.4% vs 9.5%) had significant bleeding after surgery requiring blood transfusion. However, there were no significant differences between the groups in operative or postoperative blood transfusions ( P = 0.12, 0.53), decreases in hematocrit ( P = 0.21), hospital stay ( P = 0.09), intensive care unit stay ( P = 0.41), late complications ( P = 0.45), or mortality ( P = 0.42). Although our cohort is limited in size, these results suggest that in the case of a nonelective general surgery procedure where outcomes depend on timely surgery, clopidogrel taken within 6 days before surgery should not be a reason to delay surgery. However, careful attention must be paid to meticulous hemostasis, and platelets must be readily available for transfusion in the operating room.

Clopidogrel pre-treatment in stable angina: for all patients > 6 h before elective coronary angiography or only for angiographically selected patients a few minutes before PCI? A randomized multicentre trial PRAGUE-8

AIMS

To compare two different clopidogrel regimens on the outcomes of patients undergoing elective coronary angiography (CAG)+/-ad hoc percutaneous coronary intervention (PCI).

METHODS AND RESULTS

Open-trial randomized 1028 patients with stable angina to group A ('non-selective'-clopidogrel 600 mg > 6 h before CAG; n = 513) or group B ('selective'-clopidogrel 600 mg in the cath-lab after CAG, only in case of PCI; n = 515). Combined primary endpoint was death/periprocedural myocardial infarction (MI)/stroke/re-intervention within 7 days. Secondary endpoints were troponin elevation and bleeding complications. Primary endpoint occurred in 0.8% group A patients vs. 1% group B (P = 0.749; 90% CI for the percentage difference -1.2-0.8). Periprocedural troponin elevation (> 3 x ULN) was detected in 2.6% group A vs. 3.3% group B (P = 0.475; 90% CI -2.5-1.0). Bleeding complications occurred in 3.5% group A patients vs. 1.4% group B (P = 0.025). After adjustment for covariates and factors that may influence the bleeding risk, patients in group A were shown to have more likely bleeding complications when compared with group B (OR = 3.03; 95% CI 1.14-8.10; P = 0.027).

CONCLUSION

High (600 mg) loading dose of clopidogrel before elective CAG increased the risk of minor bleeding complications, while the benefit on periprocedural infarction was not significant. Clopidogrel can be given safely in the catheterization laboratory between CAG and PCI in chronic stable angina patients.

Risk of bleeding in surgical patients treated with topical bovine thrombin sealants: a review of the literature

BACKGROUND

One of the most anticipated, but potentially serious complications during or after surgery are bleeding events. Among the many potential factors associated with bleeding complications in surgery, the use of bovine thrombin has been anecdotally identified as a possible cause of increased bleeding risk. Most of these reports of bleeding events in association with the use of topical bovine thrombin have been limited to case reports lacking clear cause and effect relationship determination. Recent studies have failed to establish significant differences in the rates of bleeding events between those treated with bovine thrombin and those treated with either human or recombinant thrombin.

METHODS

We conducted a search of MEDLINE for the most recent past 10 years (1997-2007) and identified all published studies that reported a study of surgical patients with a clear objective to examine the risk of bleeding events in surgical patients. We also specifically noted the reporting of any topical bovine thrombin used during surgical procedures. We aimed to examine whether there were any differences in the risk of bleeds in general surgical populations as compared to those studies that reported exposure to topical bovine thrombin.

RESULTS

We identified 21 clinical studies that addressed the risk of bleeding in surgery. Of these, 5 studies analyzed the use of bovine thrombin sealants in surgical patients. There were no standardized definitions for bleeding events employed across these studies. The rates of bleeds in the general surgery studies ranged from 0.1%-20.2%, with most studies reporting rates between 2.6%-4%. The rates of bleeding events ranged from 0.0%-13% in the bovine thrombin studies with most studies reporting between a 2%-3% rate.

CONCLUSION

The risk of bleeds was not clearly different in those studies reporting use of bovine thrombin in all patients compared to the other surgical populations studied. A well-designed and well-controlled study is needed to accurately examine the bleeding risks in surgical patients treated and unexposed to topical bovine thrombin, and to evaluate the independent risk associated with topical bovine thrombin as well as other risk factors.