Bleeding, blood transfusion, and increased mortality after percutaneous coronary intervention: implications for contemporary practice

Antiplatelet effects of clopidogrel and bleeding in patients undergoing coronary stent placement

BACKGROUND

In patients undergoing percutaneous coronary intervention (PCI), a link between bleeding and excess mortality has been demonstrated. A potential association of platelet response to clopidogrel and bleeding has not been well established yet.

OBJECTIVES

The aim of the present study was to assess the impact of clopidogrel responsiveness on the risk of bleeding in clopidogrel-treated patients undergoing PCI.

METHODS

Patients (n=2533) undergoing PCI after pretreatment with 600 mg of clopidogrel were enrolled in this study. Blood was obtained directly before PCI. Adenosine-diphosphate (ADP)-induced platelet aggregation was assessed on a Multiplate analyzer. The primary endpoint was the incidence of in-hospital Thrombolysis in Myocardial Infarction (TIMI) major bleeding and the secondary endpoint was in-hospital TIMI minor bleeding. Receiver-operator curve (ROC) analysis was used to derive the optimal platelet aggregation value defining enhanced clopidogrel responders for the association of measurements with major bleeding.

RESULTS

Thirty-four (1.3%) major bleeding events and 137 (5.4%) minor bleeding events were observed. The risk of a major bleeding was significantly higher in patients (n=975) with an enhanced response to clopidogrel as compared with the remaining patients (n=1558) (2.2 vs. 0.8%, unadjusted odds ratio (OR) 2.6, 95% confidence interval (CI) 1.3-5.2, P=0.005; adjusted OR 3.5, 95% CI 1.6-7.3, P=0.001). No significant differences between both groups were observed for the occurrence of minor bleeding events (P=0.68).

CONCLUSIONS

Enhanced clopidogrel responsiveness is associated with a higher risk of major bleeding. Whether guidance of antiplatelet treatment based on platelet function testing proves useful for avoiding bleeding events warrants further investigation.

[Percentage of transradial approach for interventional cardiology in the world and learning the technique]

The transradial approach has been used for the first non selective coronary angiographies but was quickly replaced by the femoral approach until a new birth in 1989 for coronary angiography in 1989 and coronary angioplasty in 1992. Transradial approach use is extremely heterogeneous in the world, dominated by some countries in Europe, Canada, and eastern Asia (India, Taiwan, China, Japan). Risk factors of failure have been well described, allowing two kinds of learning: systematic attempt in all kind of patients when working with a proctor; patient selection when beginning the technique alone in order to get a high and stable success rate from the beginning. Systematic radial approach for coronary angiography is a must to learn the technique.

[Transradial approach and kidney disease]

Patients with chronic kidney disease have a high cardiovascular risk and mortality. This problem is growing because of the aging of the population and prevalence of diabetes. Transradial approach is traditionally prohibited due to the injury that catheterization induces on this artery that could possibly influence its suitability as an arteriovenous fistula. Paradoxically, the increased risk of major vascular complications with femoral access leads to transgress this rule. Indeed, transradial approach by reducing dramatically the rate of vascular bleeding complications leads to a significant reduction of adverse events and mortality, especially in the high cardiovascular risk sub-group. In patients with chronic kidney disease, choice of vascular access site should compare the potentially fatal risk of vascular complications with the one of traumatizing the artery needed to create a distal hemodialysis access site. Thus, chronic renal insufficiency even on hemodialysis should not be an absolute contraindication to radial approach, which could be used individually by a skilled team and in a mini-invasive spirit. A large randomised study comparing radial and femoral access in this population is needed.

Patient blood management - a new paradigm for transfusion medicine?

The saving of many lives in history has been duly credited to blood transfusions. What is frequently overlooked is the fact that, in light of a wealth of evidence as well as other management options, a therapy deemed suitable yesterday may no longer be the first choice today. Use of blood has not been based upon scientific evaluation of benefits, but mostly on anecdotal experience and a variety of factors are challenging current practice. Blood is a precious resource with an ever limiting supply due to the aging population. Costs have also continually increased due to advances (and complexities) in collection, testing, processing and administration of transfusion, which could make up 5% of the total health service budget. Risks of transfusions remain a major concern, with advances in blood screening and processing shifting the profile from infectious to non‐infectious risks. Most worrying though, is the accumulating literature demonstrating a strong (often dose‐dependent) association between transfusion and adverse outcomes. These include increased length of stay, postoperative infection, morbidity and mortality. To this end, a recent international consensus conference on transfusion outcomes (ICCTO) concluded that there was little evidence to corroborate that blood would improve patients’ outcomes in the vast majority of clinical scenarios in which transfusions are currently routinely considered; more appropriate clinical management options should be adopted and transfusion avoided wherever possible. On the other hand, there are patients for whom the perceived benefits of transfusion are likely to outweigh the potential risks. Consensus guidelines for blood component therapy have been developed to assist clinicians in identifying these patients and most of these guidelines have long advocated more conservative ‘triggers’ for transfusion. However, significant variation in practice and inappropriate transfusions are still prevalent. The ‘blood must always be good philosophy’ continues to permeate clinical practice. An alternative approach, however, is being adopted in an increasing number of centres. Experience in managing Jehovah’s Witness patients has shown that complex care without transfusion is possible and results are comparable with, if not better than those of transfused patients. These experiences and rising awareness of downsides of transfusion helped create what has become known as ‘patient blood management’. Principles of this approach include optimizing erythropoiesis, reducing surgical blood loss and harnessing the patient’s physiological tolerance of anaemia. Treatment is tailored to the individual patient, using a multidisciplinary team approach and employing a combination of modalities. Results have demonstrated reduction of transfusion, improved patient outcomes and patient satisfaction. Significant healthcare cost savings have also followed. Despite the success of patient blood management programmes and calls for practice change, the potential and actual harm to patients caused through inappropriate transfusion is still not sufficiently tangible for the public and many clinicians. This has to change. The medical, ethical, legal and economic evidence cannot be ignored. Patient blood management needs to be implemented as the standard of care for all patients.

Selecting the optimal antithrombotic regimen for patients with acute coronary syndromes undergoing percutaneous coronary intervention

The wide variety of anticoagulant and antiplatelet agents available for clinical use has made choosing the optimal antithrombotic regimen for patients with acute coronary syndromes undergoing percutaneous coronary intervention a complex task. While there is no single best regimen, from a risk-benefit ratio standpoint, particular regimens may be considered optimal for different patients. We review the mechanisms of action for the commonly prescribed antithrombotic medications, summarize pertinent data from randomized trials on their use in acute coronary syndromes, and provide an algorithm (incorporating data from these trials as well as risk assessment instruments) that will help guide the decision-making process.