Early administration of clopidogrel is safe after off-pump coronary artery bypass surgery

Is administration of dual-antiplatelet therapy beneficial for patients following off-pump coronary artery bypass grafting?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether administration of dual-antiplatelet therapy (DAPT) following off-pump coronary artery bypass grafting (OPCAB) would improve postoperative clinical outcomes or minimize the incidence of postoperative graft failure. In total, 101 papers were found using the reported search, 14 of which represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. One meta-analysis and 3 randomized controlled trials showed that DAPT following OPCAB is associated with decreased incidence of saphenous vein graft occlusion. One randomized controlled trial and 4 observational studies showed no effect of DAPT on mortality following OPCAB, whereas 3 observational studies showed that DAPT decreased mortality. One meta-analysis and 4 observational studies showed that DAPT reduced the incidence of cardiac events following OPCAB. One randomized controlled trial and 4 observational studies showed that DAPT did not increase the incidence of major or minor bleeding complications following OPCAB. The results presented suggest that administration of DAPT in patients following OPCAB for at least 3 months improves saphenous vein graft patency and could be protective against recurrence of cardiac events, especially acute coronary syndrome, in comparison with aspirin monotherapy. The administration of DAPT following OPCAB is safe and is not associated with increased incidence of major or minor bleeding complications when compared with aspirin alone.

Meta-Analysis of Aspirin Versus Dual Antiplatelet Therapy Following Coronary Artery Bypass Grafting

Although aspirin monotherapy is considered the standard of care after coronary artery bypass grafting (CABG), more recent evidence has suggested a benefit with dual antiplatelet therapy (DAPT) after CABG. We performed a meta-analysis of observational studies and randomized controlled trials comparing outcomes of aspirin monotherapy with DAPT in patients after CABG. Subgroup analyses were conducted according to surgical technique (i.e., on vs off pump) and clinical presentation (acute coronary syndrome vs no acute coronary syndrome). Random effects overall risk ratios (RR) were calculated using the DerSimonian and Laird model. Eight randomized control trials and 9 observational studies with a total of 11,135 patients were included. At a mean follow-up of 23 months, major adverse cardiac events (10.3% vs 12.1%, RR 0.84, confidence interval [CI] 0.71 to 0.99), all-cause mortality (5.7% vs 7.0%, RR 0.67, CI 0.48 to 0.94), and graft occlusion (11.3% vs 14.2%, RR 0.79, CI 0.63 to 0.98) were less with DAPT than with aspirin monotherapy. There was no difference in myocardial infarction, stroke, or major bleeding between the 2 groups. In conclusion, DAPT appears to be associated with a reduction in graft occlusion, major adverse cardiac events, and all-cause mortality, without significantly increasing major bleeding compared with aspirin monotherapy in patients undergoing CABG.

Optimal anticoagulation during off pump coronary artery bypass in patients recently exposed to clopidogrel

PURPOSE

The aim of this study was to find an optimal range of activated clotting time (ACT) during off-pump coronary artery bypass surgery (OPCAB) yielding ischemic protection without the risk of hemorrhagic complications in patients with recent exposure to dual antiplatelet therapy.

MATERIALS AND METHODS

Three hundred and five patients who received aspirin and clopidogrel within 7 days of isolated multi-vessel OPCAB were retrospectively studied. Combined hemorrhagic and ischemic outcome was defined as the occurrence of 1 of the following: significant perioperative bleeding (>30% of estimated blood volume), transfusion of packed red blood cell (pRBC) ≥ 2 U, or myocardial infarction (MI). This was compared in relation to the tertile distribution of the time-weighted average ACT-212-291 sec (first tertile), 292-334 sec (second tertile), 335-485 sec (third tertile).

RESULTS

The amount of perioperative blood loss was 937 ± 313 mL, 1014 ± 340 mL, and 1076 ± 383 mL, respectively (p=0.022). Significantly more patients in the third tertile developed MI (4%, 4%, and 12%, respectively, p=0.034). The incidence of significant perioperative blood loss and transfusion of pRBC ≥ 2 U were lower in the first tertile than those of other tertiles without statistical significance. In the multivariate analysis, the first tertile was associated with a 52% risk reduction of combined hemorrhagic and ischemic outcomes (95% confidence interval: 0.25-0.92, p= 0.027).

CONCLUSION

A lower degree of anticoagulation with a reduced initial heparin loading dose should be carefully considered for patients undergoing OPCAB who have recently been exposed to clopidogrel.

Effect of one-stop hybrid coronary revascularization on postoperative renal function and bleeding: a comparison study with off-pump coronary artery bypass grafting surgery

OBJECTIVES

Although 1-stop hybrid coronary revascularization offers potential benefits for selected patients with multivessel coronary artery disease, the exposure to contrast dye and potent antiplatelet drugs could increase the risk of postoperative acute kidney injury and coagulopathy. The goal of the present study was to compare the measures of renal function, postoperative bleeding, and transfusion requirements in patients undergoing hybrid revascularization compared with off-pump coronary artery bypass grafting (CABG).

METHODS

We retrospectively analyzed the data from 141 consecutive patients who had undergone 1-stop hybrid coronary revascularization from June 2007 to January 2011. Propensity score matching with 141 off-pump CABG patients from our surgical database was performed for comparison. The change in renal function, cumulative chest tube drainage, and clinical outcome parameters were compared between the 2 groups.

RESULTS

Compared with off-pump CABG, patients undergoing hybrid revascularization had significantly less chest tube drainage at 12 hours after surgery (P = .04) and for the total amount during the postoperative period (P < .001) and required fewer blood transfusions (P = .001). The hybrid group had a higher incidence of acute kidney injury, but this did not reach statistical significance (25.2% vs 17.6%, P = .13). The hybrid group required less inotropic and vasoactive support, had fewer respiratory complications, required a shorter time of mechanical support, and had a decreased length of intensive care unit stay.

CONCLUSIONS

Compared with off-pump CABG, 1-stop hybrid coronary revascularization was associated with benefits such as less postoperative bleeding and blood transfusion requirements without significantly increasing the additional risk of acute kidney injury.

Dual anti-platelet therapy after coronary artery bypass grafting: is there any benefit? A systematic review and meta-analysis

BACKGROUND

Anti-platelet therapy is an important component of medical therapy post coronary artery bypass grafting (CABG). While aspirin administration is a Class I indication after CABG, the benefit of concomitant clopidogrel is a controversial issue.

METHODS

We searched OVID Medline, Cochrane, Scopus, and EMBASE for randomized control trials and observational studies comparing aspirin ± placebo to aspirin + clopidogrel after CABG.

RESULTS

Eleven articles (five randomized control trials and six observational studies) including 25,728 patients met inclusion criteria. Early saphenous vein graft occlusion was reduced with the use of dual anti-platelet therapy (risk ratio (RR) = 0.59, 95% CI 0.43-0.82, p = 0.02). In-hospital or 30-day mortality was lower with aspirin + clopidogrel (0.8%) compared to aspirin alone (1.9%) (p < 0.0001), while risk of angina or perioperative myocardial infarction was comparable (RR = 0.60, 95% CI 0.31-1.14, p = 0.12). Patients treated with aspirin + clopidogrel demonstrated a trend towards a higher incidence of major bleeding episodes as compared to patients treated with aspirin alone (RR = 1.17, 95% CI 1.00-1.37, p = 0.05). In a pooled analysis of studies involving off-pump CABG compared to aspirin alone, dual anti-platelet therapy reduced the risk of perioperative myocardial infarction and saphenous graft occlusion by 68% (47% to 71%) and 55% (2% to 79%) respectively.

CONCLUSION

Dual anti-platelet therapy after CABG improved early saphenous vein graft patency, but may increase the risk of bleeding. The use of dual anti-platelet therapy appears to be most beneficial in patients undergoing off-pump CABG. Prospective randomized studies are necessary to determine whether this beneficial effect of dual therapy is also achieved in patients undergoing on pump CABG.

Influence of ischemia before vein grafting on early hyperplasia of the graft and the dynamic changes of the intima after grafting

Background

To investigate both the influence of ischemia before grafting on early hyperplasia of the vein grafts, and the dynamic changes of the intima after grafting in a rabbit model of vein graft disease.

Methods

We performed paired vein graft experiments under different ischemic conditions (15 vs. 60 min; 15 vs. 90 min) in the neck of the rabbits and compared the differences between the grafts. Clopidogrel, an anti-platelet agent, was administered before and after surgery. Twenty-eight days after the grafting procedure, the veins were evaluated microscopically. The dynamic changes of the intima after grafting were evaluated by scanning electron microscopy over time.

Results

The vein grafts subjected to 60- or 90-min ischemia exhibited no differences compared to those subjected to 15-min ischemia in terms of the mean thickness of the intimal, medial, and adventitial layers of the graft. Similarly, there was no difference in the Ki-67 labeling index (proliferation marker) between the vein grafts. Vein grafts with 15-min ischemia lost endothelial cells (ECs) but healed by 3 days post graft, whereas vein grafts with 90-min ischemia suffered serious EC loss, which was restored with new ECs during days 2 to 14 post graft.

Conclusions

Ninety-minute ischemia before vein grafting can cause serious EC loss, but does not increase early intimal hyperplasia when clopidogrel is administered. Protecting the vein from ischemia and reperfusion injury preserves ECs.

Use of Aspirin and Clopidogrel After Coronary Artery Bypass Graft Surgery

Objective:

To evaluate the evidence for the use of dual antiplatelet therapy (DAPT) with aspirin and Clopidogrel following coronary artery bypass graft (CABG) surgery.

Data Sources:

Literature was accessed through PubMed (1950-November 2011), EMBASE (1976-November 2011), and the Cochrane databases using the terms Clopidogrel and coronary artery bypass graft. Citations from available articles were used for additional references and ClinicalTrials.gov was accessed for abstracts of ongoing studies.

Study Selection Ano Data Extraction:

Peer-reviewed studies that evaluated DAPT use after CABQ surgery in adult humans were assessed for inclusion.

Data Synthesis:

Four randomized clinical trials evaluating surrogate end points and 9 studies (3 subgroup analyses, 6 observational) evaluating clinical outcomes were reviewed. Three clinical trials assessing surrogate end points failed to demonstrate an improvement in graft patency with DAPT use, while 1 clinical trial found an increase in graft patency. As for clinical outcomes, 1 subgroup analysis demonstrated that the benefit of DAPT post-CABG after a non-ST-elevation acute coronary syndrome diminished following surgery, while an observational study demonstrated a trend toward decreased mortality. In post-CABG patients who did not experience acute coronary syndrome, 2 subgroup analyses proved inconclusive and an observational study found DAPT use to be associated with reducing in-hospital mortality, while another observational study was not associated with reduced long-term mortality. Three observational studies in off-pump CABG patients showed that DAPT use was feasible.

Conclusions:

Evidence for DAPT use following CABG is limited to subgroup analyses, observational studies, and trials with surrogate end points. The majority of clinical trials have failed to demonstrate an improvement in graft patency with DAPT. Current evidence does not support the use of DAPT to improve graft patency, and more evidence from randomized controlled trials assessing clinical outcomes is necessary to make definitive recommendations.

Use of clopidogrel post-coronary artery bypass surgery in canadian patients with acute coronary syndromes

BACKGROUND

Randomized trials have established the efficacy of clopidogrel in acute coronary syndromes (ACS). The benefit of clopidogrel has also been observed in the subgroup of ACS patients who subsequently undergo coronary artery bypass surgery (CABG); however, this therapy is discontinued preoperatively and the frequency with which clopidogrel is restarted post-CABG is unknown.

METHODS

We examined the pattern of clopidogrel use in the Canadian Global Registry of Acute Coronary Events (GRACE), GRACE2, and CANRACE (2003-2008) post-CABG ACS patients. We stratified the patients according to whether they underwent CABG during their index hospitalization for ACS and whether they were prescribed clopidogrel at discharge.

RESULTS

Among those patients in whom clopidogrel status at discharge was known, 5904 (60%) of 9841 were discharged from hospital on clopidogrel. Use of clopidogrel at discharge was observed in 2222 (40.8%) of 5443 patients who were medically managed (ie, did not undergo percutaneous coronary intervention [PCI] or CABG) and in 3585 (90.1%) of 3980 patients who underwent in-hospital PCI. Overall, 455 (3.3%) of 13,776 patients underwent CABG during the index hospitalization; 255 (56%) patients were started on clopidogrel during the first 24 hours, and 66 of these patients (25.9%) were discharged on clopidogrel. In contrast, 5681 (61.3%) of the 9262 patients who did not undergo in-hospital CABG were discharged on clopidogrel.

CONCLUSIONS

Although current guidelines recommend the use of clopidogrel post-CABG in patients with ACS, our observations suggest that only 1 in 4 or 5 Canadian patients are discharged on this therapy.

Randomized trial of aspirin and clopidogrel versus aspirin alone for the prevention of coronary artery bypass graft occlusion: the Preoperative Aspirin and Postoperative Antiplatelets in Coronary Artery Bypass Grafting study

BACKGROUND

Routine use of postoperative aspirin after coronary artery bypass grafting (CABG) reduces graft failure and cardiovascular events. The efficacy and safety of adding clopidogrel to aspirin for the prevention of graft failure and cardiovascular events after CABG are unknown. We performed a pilot study measuring safety and efficacy outcomes of aspirin and clopidogrel therapy after CABG.

METHODS

We randomized 100 patients undergoing CABG to receive placebo or clopidogrel started after surgery and for 30 days. All patients received aspirin 81 mg daily. Graft patency was measured by cardiac computed tomography angiography at 30 days.

RESULTS

Clinical follow-up was complete for 99 patients, and 79 (80%) underwent computed tomography angiography. The proportion of patients with ≥1 occluded graft was not significantly different between placebo and clopidogrel groups (9/39 [23.1%] vs 7/40 [17.5%], relative risk 0.95, 95% CI 0.80-1.14, P=.54). Among radial artery grafts, the placebo group had a significantly higher number of occlusions or "string signs" compared with the clopidogrel group (7/16 [43.8%] vs 2/19 [10.5%], relative risk 0.24, 95% CI 0.06-1.00, P=.05). There was no difference between placebo and clopidogrel groups in the safety outcomes of total postoperative bleeding, transfusions, bleeding events, and reexploration and in the efficacy outcomes of nonfatal myocardial infarction, stroke, and death.

CONCLUSIONS

This pilot study confirms a high rate of graft occlusion after CABG surgery and suggests that the addition of clopidogrel to aspirin is feasible and safe and may be superior for prevention of graft failure in radial artery grafts.

Dual antiplatelet therapy in patients requiring urgent coronary artery bypass grafting surgery: a position statement of the Canadian Cardiovascular Society

Acute coronary syndrome (ACS) guidelines recommend that most patients receive dual antiplatelet therapy with clopidogrel and acetylsalicylic acid (ASA) at the time of presentation to prevent recurrent ischemic events. Approximately 10% of ACS patients require coronary artery bypass grafting surgery (CABG) during the index admission. Most studies show that patients who receive ASA and clopidogrel within five days of CABG have an increase in operative bleeding. Current consensus guidelines recommend discontinuation of clopidogrel therapy at least five days before planned CABG to reduce bleeding-related events. However, high-risk individuals may require urgent surgery without delay, to reduce the risk of potentially fatal ischemic events. The present multidisciplinary position statement provides evidence- based recommendations for the optimal use of dual antiplatelet therapy to balance ischemic and bleeding risks in patients with recent ACS who may require urgent CABG.

RECOMMENDATIONS

1. All ACS patients should be considered for dual antiplatelet therapy with ASA and clopidogrel at the earliest opportunity, despite the possibility of a need for urgent CABG. 2. For patients who have received clopidogrel and ASA, and require CABG: * Those at high risk of an early fatal event (eg, with refractory ischemia despite optimal medical treatment, and with high-risk coronary anatomy (eg, severe left main stenosis with severe right coronary artery disease), should be considered for early surgery without discontinuation of clopidogrel. * In patients with a high bleeding risk (eg, previous surgery, complex surgery) who are also at high risk for an ischemic event, consideration should be given to discontinuing clopidogrel for three to five days before surgery. * Patients at a lower risk for ischemic events (most patients) should have clopidogrel discontinued five days before surgery. 3. For patients who have CABG within five days of receiving clopidogrel and ASA, the risk of major bleeding and transfusion can be minimized by applying multiple strategies before and during surgery. 4. Patients who receive clopidogrel pre-CABG for a recent ACS indication should have clopidogrel restarted after surgery to decrease the risk of recurrent ACS. 5. For patients with a recent coronary stent, the decision to continue clopidogrel until the time of surgery or to discontinue will depend on the risk and potential impact of stent thrombosis. Restarting clopidogrel after CABG will depend on whether the stented vessel was revascularized, the type of stent and the time from stent implantation. Clopidogrel should be restarted when hemostasis is assured to prevent recurrent acute ischemic events.

Off-pump coronary artery bypass: techniques, pitfalls, and results

In an attempt to advance the surgical treatment of coronary artery disease, surgeons sought a way to offer the proven benefits of coronary revascularization and avoid the side effects of cardiopulmonary bypass by performing revascularization in the beating heart (off-pump coronary artery bypass). This review will describe the development and refinement of the technique, pitfalls to its widespread adoption, and an up-to-date assessment of current results.

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.

Dual antiplatelet therapy with clopidogrel and aspirin

PURPOSE

Dual antiplatelet therapy with clopidogrel and aspirin is reviewed.

SUMMARY

Several studies have evaluated the effectiveness of clopidogrel, aspirin, or the combination of these agents in a variety of patient populations. The results of these studies have helped determine the role of clopidogrel and aspirin in evidence-based medicine. Investigators in the Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management and Avoidance trial concluded that patients with multiple atherothrombotic risk factors who have stable cardiovascular disease (CVD) or no history of CVD or documented vascular disease should not receive combination clopidogrel and aspirin due to an increase in death. Patients with established vascular disease being treated with clopidogrel and aspirin may benefit from the combination through a reduction in the rate of myocardial infarction, stroke, or death from cardiovascular causes. The combination should not be used longer than one year since the benefits past one year have not been established by clinical trials, though consideration for longer treatment may be warranted in patients with stent implantation. One of the inherent risks associated with using clopidogrel and aspirin is the risk for increased bleeding. If a patient is started on combination therapy, it is imperative to monitor for signs and symptoms of bleeding.

CONCLUSION

Dual antiplatelet therapy with clopidogrel and aspirin should be used in certain patients, such as those with any type of acute coronary syndrome or stent implantation, if there are no contraindications to combined therapy. The risk of bleeding should be considered in patients receiving the combination.

Simultaneous "hybrid" percutaneous coronary intervention and minimally invasive surgical bypass grafting: feasibility, safety, and clinical outcomes

Surgical and percutaneous coronary artery intervention revascularization are traditionally considered isolated options. A simultaneous hybrid approach may allow an opportunity to match the best strategy for a particular anatomic lesion. Concerns regarding safety and feasibility of such an approach exist. We examined the safety, feasibility, and early outcomes of a simultaneous hybrid revascularization strategy (minimally invasive direct coronary bypass grafting of the left anterior descending [LAD] artery and drug-eluting stent [DES] to non-LAD lesions) in 13 patients with multivessel coronary artery disease that underwent left internal mammary artery to LAD minimally invasive direct coronary bypass performed through a lateral thoracotomy, followed by stenting of non-LAD lesions, in a fluoroscopy-equipped operating room. Assessment of coagulation parameters was also undertaken. Inhospital and postdischarge outcomes of these patients were compared to a group of 26 propensity score matched parallel controls that underwent standard off-pump coronary artery bypass. Baseline characteristics were similar in both groups. All hybrid patients were successfully treated with DES and no inhospital mortality occurred in either group. Hybrid patients had a shorter length of stay (3.6 +/- 1.5 vs 6.3 +/- 2.3 days, P < .0001) and intubation times (0.5 +/- 1.3 vs 11.7 +/- 9.6 hours, P < .02). Despite aggressive anticoagulation and confirmed platelet inhibition, hybrid patients had less blood loss (581 +/- 402 vs 1242 +/- 941 mL, P < .05) and decreased transfusions (0.33 +/- 0.49 vs 1.47 +/- 1.53 U, P < .01). Six-month angiographic vessel patency and major adverse cardiac events were similar in the hybrid and off-pump coronary artery bypass groups. A simultaneous hybrid approach consisting of minimally invasive coronary artery bypass grafting with left internal mammary artery to LAD combined with revascularization of the remaining coronary targets using percutaneous coronary artery intervention with DES is a feasible option accomplished with acceptable clinical outcomes without increased bleeding risk.

Early and Midterm Results of Off-Pump Coronary Artery Bypass Grafting

BACKGROUND

Early outcomes of off-pump coronary artery bypass grafting have been documented by numerous studies. However, there have been few reports concerning midterm outcomes after off-pump coronary artery bypass grafting.

METHODS

We retrospectively reviewed the records of 602 consecutive patients (24.8% female) who underwent isolated off-pump coronary artery bypass grafting between April 2001 and July 2004. Mean age was 66.7 +/- 9.3 years. Mean Canadian Cardiovascular Society score was 2.5 +/- 0.9. Early postoperative angiograms were evaluated during the same period of hospitalization. Midterm outcomes, including overall patient survival, freedom from cardiac death, and freedom from the combined endpoint of cardiac events, were evaluated.

RESULTS

The average number of distal anastomoses per patient was 3.6 +/- 1.4. The average operation time was 286.1 +/- 72.1 minutes. Long segmental reconstruction of the left anterior descending coronary artery was performed in 218 patients (36.2%). Total arterial grafting was performed in 466 patients (77.4%). Thirty-day mortality was 0.5%. Overall patency rate for all grafts and anastomoses was 97.5% and 97.6%, respectively. Mean follow-up time was 2.9 +/- 1.0 years. Cumulative patient survival at 5 years was 87.9% +/- 2.4%. Freedom from cardiac death was 97.7% +/- 0.6% at 5 years. Freedom from the combined endpoint of cardiac events was 83.8% +/- 2.3% at 5 years.

CONCLUSIONS

Early and midterm outcomes after off-pump coronary artery bypass grafting have acceptable mortality and cardiac events rates, with favorable early graft patency rates.