Anti-platelet and anti-thrombotic approaches in patients undergoing percutaneous coronary intervention

Effects of Ticagrelor versus Clopidogrel in Patients with Coronary Bifurcation Lesions Undergoing Percutaneous Coronary Intervention

Background

Percutaneous treatment of coronary bifurcation lesions can potentially lead to higher risk of ischemic events than the nonbifurcation ones, thus calling for further optimization of dual antiplatelet therapy (DAPT). This study aimed to compare the clinical outcomes from ticagrelor and clopidogrel in bifurcation lesions patients undergoing percutaneous coronary intervention (PCI).

Methods

We performed a retrospective cohort study in patients with coronary bifurcation lesions. A total of 553 patients discharged on ticagrelor or clopidogrel combined with aspirin were recruited for 1-year follow-up. The incidences of primary endpoint (major adverse cardiovascular event [MACE]: a composite of cardiac death, myocardial infarction [MI] or stroke), secondary endpoints (the individual component of the primary endpoint or definite/probable stent thrombosis), and major bleeding (Bleeding Academic Research Consortium [BARC]≥3 bleeding events) were evaluated. To minimize the selection bias, a propensity score-matched population analysis was also conducted.

Results

The risks of both primary endpoint (8.15% and 12.01% for the ticagrelor and clopidogrel groups, respectively; adjusted hazards ratio [HR]: 0.488, 95% confidence interval [CI]: 0.277-0.861, P=0.013) and MI (4.44% and 8.48% for the ticagrelor and clopidogrel groups, respectively; adjusted HR: 0.341, 95% CI: 0.162-0.719, P=0.005) were significantly reduced in the ticagrelor group as compared with those of the clopidogrel counterpart, whereas the risk of major bleeding was comparable (2.96% and 2.47% for the ticagrelor and clopidogrel groups, respectively; adjusted HR: 0.972, 95% CI: 0.321-2.941, P=0.960). Propensity score-matched analysis confirmed such findings.

Conclusions

For patients with bifurcation lesions after PCI, ticagrelor treatment shows lower MACE and MI rates than the clopidogrel one, along with comparable major bleeding.

Monitoring and Reversal of Anticoagulation and Antiplatelets

Since percutaneous transluminal coronary angioplasty was first described and the breakthrough studies of the role of stents were reported, the evolution in anticoagulation and antiplatelet therapy used during percutaneous coronary intervention (PCI) has reduced periprocedural ischemic events and stent thrombosis. Although greater combinations and doses of anticoagulation with antiplatelets seem to provide the best protection against thrombogenic and embolic events, there is a significant trade-off with a higher risk of major and minor bleeding episodes. This review article expands on each of the commonly used antiplatelet and anticoagulants used at time of PCI, focusing on drug monitoring and reversal.

Catheter venography and endovascular treatment of chronic cerebrospinal venous insufficiency

Multiple sclerosis (MS) is a disorder characterized by damage to the myelin sheath insulation of nerve cells of the brain and spinal cord affecting nerve impulses which can lead to numerous physical and cognitive disabilities. The disease, which affects over 500,000 people in the United States alone, is widely believed to be an autoimmune condition potentially triggered by an antecedant event such as a viral infection, environmental factors, a genetic defect or a combination of each. Chronic cerebrospinal venous insufficiency (CCSVI) is a condition characterized by abnormal venous drainage from the central nervous system that has been theorized to have a possible role in the pathogenesis and symptomatology of MS (1). A significant amount of attention has been given to this theory as a possible explanation for the etiology of symptoms related to MS patients suffering from this disease. The work of Dr. Zamboni, et al, who reported that treating the venous stenoses causing CCSVI with angioplasty resulting in significant improvement in the symptoms and quality of life of patients with MS (2) has led to further interest in this theory and potential treatment. The article presented describes endovascular techniques employed to diagnose and treat patients with MS and CCSVI.

Platelet activation in patients with atherosclerotic renal artery stenosis undergoing stent revascularization

BACKGROUND AND OBJECTIVES

Soluble CD40 ligand (sCD40L) is a marker of platelet activation; whether platelet activation occurs in the setting of renal artery stenosis and stenting is unknown. Additionally, the effect of embolic protection devices and glycoprotein IIb/IIIa inhibitors on platelet activation during renal artery intervention is unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Plasma levels of sCD40L were measured in healthy controls, patients with atherosclerosis without renal stenosis, and patients with renal artery stenosis before, immediately after, and 24 hours after renal artery stenting.

RESULTS

Soluble CD40L levels were higher in renal artery stenosis patients than normal controls (347.5 ± 27.0 versus 65.2 ± 1.4 pg/ml, P < 0.001), but were similar to patients with atherosclerosis without renal artery stenosis. Platelet-rich emboli were captured in 26% (9 of 35) of embolic protection device patients, and in these patients sCD40L was elevated before the procedure. Embolic protection device use was associated with a nonsignificant increase in sCD40L, whereas sCD40L declined with abciximab after the procedure (324.9 ± 42.5 versus 188.7 ± 31.0 pg/ml, P = 0.003) and at 24 hours.

CONCLUSIONS

Atherosclerotic renal artery stenosis is associated with platelet activation, but this appears to be related to atherosclerosis, not renal artery stenosis specifically. Embolization of platelet-rich thrombi is common in renal artery stenting and is inhibited with abciximab.

Regulation of functionally active P2Y12 ADP receptors by thrombin in human smooth muscle cells and the presence of P2Y12 in carotid artery lesions

OBJECTIVE

The platelet P2Y12 ADP receptor is a well-known target of thienopyridine-type antiplatelet drugs. This study is the first to describe increased transcriptional expression of a functionally active P2Y12 in response to thrombin in human vascular smooth muscle cells (SMC).

METHODS AND RESULTS

On exposure to thrombin, P2Y12 mRNA was transiently increased, whereas total protein and cell surface expression of P2Y12 were markedly increased within 6 hours and remained elevated over 24 hours. This effect was mediated by activation of nuclear factor κB. Preincubation with thrombin significantly enhanced the efficacy of the P2Y receptor agonist 2-methylthio-ADP to induce interleukin 6 expression and SMC mitogenesis. Effects induced by 2-methylthio-ADP were prevented by RNA interference-mediated knockdown of P2Y12 and a selective P2Y12-antagonist R-138727, the active metabolite of prasugrel. In addition, positive P2Y12 immunostaining was shown in SMC of human carotid artery plaques and was found to colocalize with tissue factor, the rate-limiting factor of thrombin formation in vivo.

CONCLUSIONS

These data suggest that the P2Y12 receptor not only is central to ADP-induced platelet activation but also may mediate platelet-independent responses, specifically under conditions of enhanced thrombin formation, such as local vessel injury and atherosclerotic plaque rupture.

Prevalence of Helicobacter pylori positivity in patients undergoing percutaneous coronary intervention

BACKGROUND

The adverse effect of haemorrhagic complications after percutaneous coronary intervention (PCI) on outcome is well established with Helicobacter pylori infection known to be an important precipitant of peptic ulcer disease in patients receiving non-steroidal anti-inflammatory drug therapy. The prevalence of H. pylori positivity in patients undergoing PCI and receiving subsequent antiplatelet therapy is unknown.

AIMS

We sought to determine the prevalence and features associated with H. pylori positivity in patients undergoing PCI.

METHODS

All patients undergoing PCI between August 2008 and April 2009 were identified and assessed for H. pylori positivity with serological status determined by using a commercially supplied enzyme-linked immunosorbent assay.

RESULTS

A total of 245 patients undergoing PCI during the study period had samples obtained for H. pylori serology. Of these, 91 were positive for H. pylori serology (37%) and 148 were negative (60%) with six samples being equivocal (3%). Of those patients positive for H. pylori, 75% were on agents at admission known to promote or precipitate gastrointestinal haemorrhage. Patients positive for H. pylori tended to be older, with increased creatinine and more likely to be receiving proton pump inhibitor therapy.

CONCLUSIONS

In an unselected cohort of patients undergoing PCI in a single centre, we detected a prevalence of H. pylori positivity in 37% of patients; this denotes a potentially treatable precipitant of haemorrhage in a considerable portion of patients receiving dual antiplatelet therapy after PCI. Further prospective study is required to determine if the presence of H. pylori positivity is associated with adverse events in terms of gastrointestinal and cardiac outcomes.