Hemorrhagic and vascular complications after percutaneous coronary intervention with adjunctive abciximab

Evolution of anticoagulant and antiplatelet therapy: benefits and risks of contemporary pharmacologic agents and their implications for myonecrosis and bleeding in percutaneous coronary intervention

Periprocedural myonecrosis, as evidenced by elevated creatine kinase-myocardial bound (CK-MB) levels, occurs in up to 25% of patients undergoing percutaneous coronary intervention (PCI) and has been linked with an increased risk of adverse short- and long-term clinical outcomes. Such myonecrosis arises from three main pathophysiological mechanisms: procedure-related complications, lesion-specific characteristics (e.g., large thrombus burden, plaque volume), and patient-specific characteristics (e.g., genetic predisposition, arterial inflammation). Periprocedural myonecrosis has not been definitively identified as the cause of postprocedural ischemic events, although agents that reduce or prevent thrombosis--including aspirin, thienopyridines, heparin, low-molecular-weight heparins, glycoprotein IIb/IIIa inhibitors, and direct thrombin inhibitors--have been shown to reduce the incidence of ischemic outcomes in this population, as have agents that reduce inflammation (aspirin, statins). At the same time, antithrombotic agents are known to increase the risk of bleeding and the use of transfusions, which have likewise been associated with worse outcomes in these patients. Thus, optimal management of patients undergoing PCI represents a balance between minimizing the risk of ischemic outcomes and simultaneously minimizing the risk of major bleeding. It may be that patients who have only minor, untreated postprocedural elevations in CK-MB level (with no clinical or angiographic signs of ischemia) might have a better prognosis than patients who have normal CK-MB levels but who suffer major bleeding complications.

The economic burden of complications during percutaneous coronary intervention

BACKGROUND

Technological advances have enabled percutaneous coronary intervention (PCI) to be applied with expanding indications. However, escalating costs are of concern. This study assessed the incremental medical costs of major in-hospital procedural complications incurred by patients undergoing PCI.

METHODS

We considered all patients undergoing elective, urgent, or emergent PCI at Mayo Clinic Rochester between 3/1/1998-3/31/2003 in analyses. Clinical, angiographic, and outcome data were derived from the Mayo Clinic PCI Registry. In-hospital PCI complications included major adverse cardiac and cerebrovascular events (MACCE) and bleeding of clinical significance. Administrative data were used to estimate total costs in standardised, year 2004, constant-US dollars. We used generalised linear modeling to estimate costs associated with complications adjusting for baseline and procedural characteristics.

RESULTS

1071 (13.2%) of patients experienced complications during hospitalisation. Patients experiencing complications were older, more likely to present with emergent PCI, recent or prior myocardial infarction, multi-vessel disease, and comorbid conditions than patients who did not experience these events. Unadjusted total costs were, on average, $27,865+/-$39,424 for complicated patient episodes compared to $12,279+/-$6796 for episodes that were complication free (p<0.0001). Adjusted mean costs were $6984 higher for complicated PCIs compared with uncomplicated PCI episodes (95% CI of cost difference: $5801, $8168). Incremental costs associated with isolated bleeding events, MACCE, or for both bleeding and MACCE events were $5883, $5086, and $15,437, respectively (p<0.0001).

CONCLUSIONS

This high-volume study highlights the significant economic burden associated with procedural complications. Resources and systems approaches to minimising clinical and economic complications in PCI are warranted.

Biomaterial-associated thrombosis: roles of coagulation factors, complement, platelets and leukocytes

Our failure to produce truly non-thrombogenic materials may reflect a failure to fully understand the mechanisms of biomaterial-associated thrombosis. The community has focused on minimizing coagulation or minimizing platelet adhesion and activation. We have infrequently considered the interactions between the two although we are generally familiar with these interactions. However, we have rarely considered in the context of biomaterial-associated thrombosis the other major players in blood: complement and leukocytes. Biomaterials are known agonists of complement and leukocyte activation, but this is frequently studied only in the context of inflammation. For us, thrombosis is a special case of inflammation. Here we summarize current perspectives on all four of these components in thrombosis and with biomaterials and cardiovascular devices. We also briefly highlight a few features of biomaterial-associated thrombosis that are not often considered in the biomaterials literature: The importance of tissue factor and the extrinsic coagulation system. Complement activation as a prelude to platelet activation and its role in thrombosis. The role of leukocytes in thrombin formation. The differing time scales of these contributions.

Modulating thrombotic potential in catheter-based percutaneous coronary and peripheral vascular interventions

Thrombosis is an obligatory consequence of all percutaneous vascular interventions. Balloon angioplasty, intravascular stents and other devices routinely used to facilitate dilatation of critical vascular stenoses result in fracture of the intima and exposure of the thrombogenic subendothelium with initiation and perpetuation of platelet activation and aggregation. This not uncommonly results in thrombus formation that may lead to abrupt vessel closure, distal ischemia and tissue infarction, and target organ dysfunction. Fortunately, advances in our understanding of the mechanisms that underlie vascular thrombosis have led to advances in the use of adjunctive pharmacological agents that modulate this pathophysiological response and have led to important reductions in the incidence and severity of thrombotic complications of percutaneous transluminal interventions.

Effect of a humanized monoclonal antibody to von Willebrand factor in a canine model of coronary arterial thrombosis

The purpose of this study was to investigate the antithrombotic effect and bleeding time prolongation of AJW200, a humanized monoclonal antibody to von Willebrand factor (vWF), in a canine model of coronary arterial thrombosis. AJW200 significantly inhibited cyclic flow reductions, as well as botrocetin-induced platelet aggregation, at 0.1 mg/kg. A significant prolongation of bleeding time was observed at 0.3-1 mg/kg. Approximately 50% occupancy of vWF (approximately 0.7 microg/ml AJW200 in plasma) and 80-100% occupancy (approximately 20 microg/ml AJW200 in plasma) were needed for the antithrombotic effect and the extensive prolongation of bleeding time, respectively. On the contrary, the minimal effective dose of abciximab (0.8 mg/kg) was associated with a significant prolongation of bleeding time. These results suggest that the pharmacological blockade of platelet glycoprotein (GP) Ib-vWF interaction with AJW200 results in a safer antithrombotic profile than platelet GPIIb/IIIa blockade with abciximab in dogs.