Clopidogrel loading dose and bleeding outcomes in patients undergoing urgent coronary artery bypass grafting

Postoperative Bleeding Following Preoperative Clopidogrel Administration in Patients with Haemoglobin Level Above 110 g/L Undergoing Urgent CABG

INTRODUCTION

Patients with acute coronary syndrome usually receive dual antiplatelet therapy (DAPT) (usually clopidogrel + aspirin) prior to coronary catheterization, and approximately 10% of these patients require coronary artery bypass grafting (CABG). DAPT has favorable effects on prevention of thrombus formation, but it can have deleterious effects on surgical hemostasis. Anaemia, if present, gives additional risk to such patients. The aim of this study was to examine if DAPT affects postoperative bleeding in patients with haemoglobin levels above 110 g/L, who underwent urgent or emergent CABG, less than five days after stopping DAPT therapy.

METHODS

Data were collected prospectively on 122 CABG patients, operated by a surgical team from March 2008 to August 2013. Patients were stratified into two groups: group 1 received DAPT within 5 days of CABG (n=65), and group 2 where DAPT was discontinued for more than 5 days prior to CABG (n=57). All patients were diagnosed with acute coronary syndrome preoperatively, and all of them had haemoglobin levels above 110 g/L. Patients who needed reoperation, combined procedures, or off-pump revascularization were excluded.

RESULTS

There was no hospital mortality. Mean chest tube losses after the surgical revascularization did not differ significantly, but group 1 received a higher quantity of transfused red blood cells and platelets.

CONCLUSION

Urgent and emergent surgical revascularization using extracorporeal circulation in patients with acute coronary syndrome whose preoperative haemoglobin levels are above 110 g/L is a safe and effective procedure. We suggest that, where indicative, one may perform CABG in less than 5 days after the clopidogrel discontinuation.

Dual antiplatelet therapy may increase the risk of non-intracranial haemorrhage in patients with minor strokes: a subgroup analysis of the CHANCE trial

Aim

The aim of this study was to explore the difference between haemorrhagic events among those patients on either aspirin or aspirin plus clopidogrel who were enrolled in the Clopidogrel in High-Risk Patients with Acute Non-disabling Ischemic Cerebrovascular Events (CHANCE) trial.

Methods

This was an ad hoc analysis of the CHANCE trial; data on all patients with any haemorrhagic event were reviewed and analysed. Cox proportional hazards regression was used to determine factors association with any bleeding.

Results

In the CHANCE trial, there were a total of 101 (2%) haemorrhagic events reported from 50 different hospitals. The clopidogrel–aspirin group had 60 (2.3%) cases and the aspirin group had 41 (1.6%, p=0.09). Moderate or severe haemorrhagic events occurred in 7 patients (0.3%) in the clopidogrel–aspirin group and in 8 (0.3%) in the aspirin group (p=0.73). Of 36 (0.7%) cases of intracranial haemorrhages, 20 (0.4%) were in the clopidogrel–aspirin group and 16 (0.3%) in the aspirin group. Each group had 8 (0.3%) cases of symptomatic haemorrhagic strokes. Other common haemorrhagic events included 24 (0.5%) cases of skin bruises, 13 (0.3%) gastrointestinal haemorrhages, 9 (0.2%) gum haemorrhages and 8 (0.2%) intraocular haemorrhages.

Conclusions

There was no overall significant difference in haemorrhagic events (p=0.29), especially in the rate of intracranial haemorrhages between the 2 treatment groups. However, patients enrolled with minor strokes had an increased risk of haemorrhagic events regardless of treatment group, not seen in patients with high-risk transient ischaemic attacks. Being elderly, of male gender and with a history of aspirin or proton pump inhibitor usage were associated with increased risk of haemorrhage. Patients with higher body mass index had lower risk of haemorrhagic events.

Trial registration number

NCT00979589.

Predicting Likelihood for Coronary Artery Bypass Grafting After Non-ST-Elevation Myocardial Infarction: Finding the Best Prediction Model

BACKGROUND

Up to half of patients with non-ST-elevation myocardial infarction (NSTEMI) do not receive dual antiplatelet therapy before angiography "pretreatment" because of the risk of increased bleeding if coronary artery bypass grafting (CABG) operation is needed. Several models have been published that predict the likelihood of CABG after NSTEMI, but they have not been independently validated. The purpose of this study was to validate these models and improve the best one.

METHODS

We studied patients with NSTEMI who were enrolled in the 24-center Translational Research Investigating Underlying Disparities in Acute Myocardial Infarction Patients' Health Status (TRIUMPH) registry between 2005 and 2008. Previous CABG prediction models were assessed using c-statistics and calibration assessments to determine the best model. Variables from TRIUMPH likely to be associated with CABG were tested to see whether they could improve the best model's performance.

RESULTS

Among 2,473 patients with NSTEMI, 11.8% underwent in-hospital CABG. C-statistics for the Modified Thrombolysis in Myocardial Infarction, Treat Angina With Aggrastat and Determine the Cost of Therapy With an Invasive or Conservative Strategy-Thrombolysis in Myocardial Infarction 18, Poppe, and Global Risk of Acute Coronary Events (GRACE) models were 0.54, 0.61, 0.61, and 0.62, respectively. The GRACE model showed the best discrimination and calibration. From the TRIUMPH registry, preselected variables were added to the GRACE model but did not significantly improve model discrimination. A GRACE model risk score of less than 9 had high sensitivity (96%), thus making it useful for predicting patients with NSTEMI who were at low risk for requiring CABG, which included approximately 21% of patients with NSTEMI.

CONCLUSIONS

This study could not improve on the GRACE model, which had the best predictive value for identifying a need for CABG after NSTEMI with a broader range of predicted risk levels and high sensitivity, especially in patients with scores lower than 9.

Individualization of treatments with drugs metabolized by CES1: combining genetics and metabolomics

CES1 is involved in the hydrolysis of ester group-containing xenobiotic and endobiotic compounds including several essential and commonly used drugs. The individual variation in the efficacy and tolerability of many drugs metabolized by CES1 is considerable. Hence, there is a large interest in individualizing the treatment with these drugs. The present review addresses the issue of individualized treatment with drugs metabolized by CES1. It describes the composition of the gene encoding CES1, reports variants of this gene with focus upon those with a potential effect on drug metabolism and provides an overview of the protein structure of this enzyme bringing notice to mechanisms involved in the regulation of enzyme activity. Subsequently, the review highlights drugs metabolized by CES1 and argues that individual differences in the pharmacokinetics of these drugs play an important role in determining drug response and tolerability suggesting prospects for individualized drug therapies. Our review also discusses endogenous substrates of CES1 and assesses the potential of using metabolomic profiling of blood to identify proxies for the hepatic activity of CES1 that predict the rate of drug metabolism. Finally, the combination of genetics and metabolomics to obtain an accurate prediction of the individual response to CES1-dependent drugs is discussed.

Feasibility and Early Safety of Single-Stage Hybrid Coronary Intervention and Valvular Cardiac Surgery

BACKGROUND

Hybrid percutaneous coronary intervention offers an alternative method of revascularization for high-risk surgical populations. We report the outcomes of a single-stage hybrid strategy in valvular cardiac surgery and explore its effects on operative risk and bleeding.

METHODS

In a hybrid operating room, 26 patients underwent hybrid surgery consisting of femoral arterial access, then coronary stenting followed by valve surgery, with appropriate heparin dosing. Clopidogrel (300 mg) was given on anesthesia induction in nonreoperative cases, or at the time of cross clamping (after stenting) for reoperative cases.

RESULTS

Mean follow-up was 680 ± 277 days. The planned coronary stenting and surgery was successful in all patients. Major cardiovascular and cerebrovascular adverse events occurred in 1 patient, with no inhospital deaths observed. No vascular complication or stent thrombosis was observed with the described antiplatelet regimen. Outcomes were comparable to those of standard bypass valve replacement surgery.

CONCLUSIONS

This study demonstrates the feasibility and early safety of a single-stage hybrid strategy with coronary stenting followed by valvular surgery in patients at increased surgical risk. Hybrid procedures may lower operative risk by eliminating or reducing the need for bypass grafting.

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.

Feasibility of diagnosis of postcardiotomy tamponade by miniaturized transesophageal echocardiography

BACKGROUND

Pericardial tamponade after cardiac surgery is a critical diagnosis that can be difficult to diagnose using conventional cardiac monitoring. Transesophageal echocardiography can provide comprehensive information to make the diagnosis but is not always available, whereas transthoracic echocardiography has its utility limited because of the body habitus or other surgical effects. New monitoring devices, miniaturized hemodynamic transesophageal echocardiography (hTEE), which allows point of care assessment of cardiac filling and functions, may aid in diagnosis of postcardiotomy tamponade.

METHODS

From May 2011 to July 2013, 21 patients underwent hTEE to rule out pericardial tamponade for clinical suspicion of tamponade after open heart surgery. The hTEE images were reviewed, and the patient outcomes were analyzed.

RESULTS

Nine patients showed no evidence of pericardial collection and did not require reexploration. Two patients showed a presence of small hematoma without ventricular compression and also did not undergo exploration. Ten patients were positive for pericardial tamponade (effusion or hematoma with ventricular compression); eight of these cases underwent emergent surgical exploration. Of the two patients who did not undergo immediate reoperation, one was managed by chest tube manipulation and the other patient underwent subsequent surgical exploration after his extensive coagulopathy was corrected by medical treatment.

CONCLUSIONS

The diagnosis of pericardial tamponade postcardiotomy is feasible using a disposable hTEE based on our limited experience. We avoided unnecessary explorations while concomitantly made prompt diagnosis in emergent situations. The hTEE device was a valuable tool in hemodynamic management in the intensive care unit, allowing rapid evaluations.

Management of patients with recently implanted coronary stents on dual antiplatelet therapy who need to undergo major surgery

About 5% of patients undergoing coronary stenting need to undergo surgery within the next year. The risk of perioperative cardiac ischemic events, particularly stent thrombosis (ST), is high in these patients, because surgery has a prothrombotic effect and antiplatelet therapy is often withdrawn in order to avoid bleeding. The clinical and angiographic predictors of ST are well known, and the proximity to an acute coronary syndrome adds to the risk. The current guidelines recommend delaying non-urgent surgery for at least 6 weeks after the placement of a bare metal stent and for 6-12 months after the placement of a drug-eluting stent, when the risk of ST is reduced. However, in the absence of formal evidence, these recommendations provide little support with regard to managing urgent operations. When surgery cannot be postponed, stratifying the risk of surgical bleeding and cardiac ischemic events is crucial in order to manage perioperative antiplatelet therapy in individual cases. Dual antiplatelet therapy should not be withdrawn for minor surgery or most gastrointestinal endoscopic procedures. Aspirin can be safely continued perioperatively in the case of most major surgery, and provides coronary protection. In the case of interventions at high risk for both bleeding and ischemic events, when clopidogrel withdrawal is required in order to reduce perioperative bleeding, perioperative treatment with the short-acting intravenous glycoprotein IIb-IIIa inhibitor tirofiban is safe in terms of bleeding, and provides strong antithrombotic protection. Such surgical interventions should be performed at hospitals capable of performing an immediate percutaneous coronary intervention at any time in the case of acute myocardial ischemia.