Oral P2Y12Receptor Inhibitors in Hemodialysis Patients Undergoing Percutaneous Coronary Interventions: Current Knowledge and Future Directions

Antiplatelet Therapy in End-stage Renal Disease Patients on Maintenance Dialysis: a State-of-the-art Review

Patients with end-stage renal disease (ESRD) on maintenance dialysis have an increased risk of ischaemic events, such as recurrent myocardial infarction (MI) and stroke. Potent antiplatelet therapy may help mitigate this risk. Nonetheless, ERSD patients are also at increased risk of bleeding due to their complex vascular milieu, which limits the routine use of potent P2Y12 inhibitors. Moreover, these patients are often underrepresented or excluded from major clinical trials leaving a significant gap in existing knowledge. Understanding the mechanisms of this paradox may serve as a benchmark for the development of ESRD trials. The present review aims to provide an overview of the pathophysiological nature of increased bleeding and ischaemic risks in ERSD patients as well as summarize available evidence of antiplatelet use and propose new concepts to guide physicians in selecting appropriate drug regimes for this high-risk cohort.

Ticagrelor inhibits platelet aggregation and reduces inflammatory burden more than clopidogrel in patients with stages 4 or 5 chronic kidney disease

BACKGROUND

No study has compared pharmacologic properties of ticagrelor and clopidogrel in non-dialysis patients with stage 4-5 chronic kidney disease (CKD).

METHODS

We conducted a double-blind RCT to compare effects of ticagrelor and clopidogrel in 48 CKD, with the primary outcome of ADP-induced platelet aggregation (WBPA) after 2 weeks of DAPT. In a parallel arm, we compared effects of 2 weeks of ticagrelor plus aspirin on mean changes in WBPA and markers of thromboinflammation among non-CKD controls (n = 26) with that of CKD in the ticagrelor-arm.

RESULTS

Average age of CKD was 53.7 years, with 62% women, 54% African American, and 42% with stage 5 CKD. Ticagrelor generated statistically lower WBPA values post treatment [median 0 Ω (IQR 0, 2)] vs. clopidogrel [median 0 Ω (IQR 0, 5)] (P = 0.002); percent inhibition of WBPA was greater (87 ± 22% vs. 63 ± 50%; P = 0.04; and plasma IL-6 levels were much lower (8.42 ± 1.73 pg/ml vs. 18.48 ± 26.56 pg/ml; P = 0.04). No differences in mean changes in WBPA between CKD-ticagrelor and control groups were observed. Ticagrelor- DAPT reduced levels of IL-1α and IL-1β in CKD-ticagrelor and control groups, attenuated lowering of TNFα and TRAIL levels in CKD-ticagrelor (vs controls), and had global changes in correlation between various cytokines in a subgroup of CKD-ticagrelor subjects not on statins (n = 10). Peak/trough levels of ticagrelor/metabolite were not different between CKD-ticagrelor and control groups.

CONCLUSIONS

We report significant differences in platelet aggregation and anti-inflammatory properties between ticagrelor- and clopidogrel-based DAPT in non-dialysis people with stage 4-5 CKD. These notable inflammatory responses suggest ticagrelor-based DAPT might lower inflammatory burden of asymptomatic patients with stage 4 or 5 CKD. (clinicaltrials.gov # NCT03649711).

Platelet-Dependent Inflammatory Dysregulation in Patients with Stages 4 or 5 Chronic Kidney Disease: A Mechanistic Clinical Study

Background

Chronic kidney disease (CKD) is characterized by dysregulated inflammation that worsens with CKD severity. The role of platelets in modulating inflammation in stage 4 or 5 CKD remains unexplored. We investigated whether there are changes in platelet-derived thromboinflammatory markers in CKD with dual antiplatelet therapy (DAPT; aspirin 81 mg/d plus P2Y12 inhibitor).

Methods

In a mechanistic clinical trial, we compared platelet activation markers (aggregation and surface receptor expression), circulating platelet-leukocyte aggregates, leukocyte composition (monocyte subtypes and CD11b surface expression), and plasma cytokine profile (45 analytes) of non-CKD controls (n=26) and CKD outpatients (n=48) with a glomerular filtration rate (GFR) <30 ml/min per 1.73 m² on 2 weeks of DAPT.

Results

Patients with CKD demonstrated a reduced mean platelet count, elevated mean platelet volume, reduced platelet-leukocyte aggregates, reduced platelet-bound monocytes, higher total non-classic monocytes in the circulation, and higher levels of IL-1RA, VEGF, and fractalkine (all P<0.05). There were no differences in platelet activation markers between CKD and controls. Although DAPT reduced platelet aggregation in both groups, it had multifaceted effects on thromboinflammatory markers in CKD, including a reduction in PDGF levels in all CKD individuals, reductions in IL-1β and TNF-α levels in select CKD individuals, and no change in a number of other cytokines. Significant positive correlations existed for baseline IL-1β, PDGF, and TNF-α levels with older age, and for baseline TNF-α levels with presence of diabetes mellitus and worse albuminuria. Mean change in IL-1β and PDGF levels on DAPT positively correlated with younger age, mean change in TNF-α levels with higher GFR, and mean changes in PDGF, and TRAIL levels correlated with worse albuminuria. Minimum spanning trees plot of cytokines showed platelet-derived CD40L had a large reduction in weight factor after DAPT in CKD. Additionally, platelet-derived IL-1β and PDGF were tightly correlated with other cytokines, with IL-1β as the hub cytokine.

Conclusions

Attenuated interactions between platelets and leukocytes in the CKD state coincided with no change in platelet activation status, an altered differentiation state of monocytes, and heightened inflammatory markers. Platelet-derived cytokines were one of the central cytokines in patients with CKD that were tightly correlated with others. DAPT had multifaceted effects on thromboinflammation, suggesting that there is platelet-dependent and -independent inflammation in stage 4 or 5 CKD.

Comparative Effectiveness and Safety of Oral P2Y12 Inhibitors in Patients on Chronic Dialysis

Introduction

Although oral P2Y₁₂ inhibitors (P2Y12-Is) are one of the most commonly prescribed medication classes in patients with end stage kidney disease on dialysis (ESKD), scarce data exist regarding their benefits and risks.

Methods

We compared effectiveness and safety of clopidogrel, prasugrel, and ticagrelor in a longitudinal study using the United States Renal Data System registry of Medicare beneficiaries with ESKD. Individuals who filled new P2Y12-I prescriptions between 2011 and 2015 were included and followed until death or censoring. The primary exposure variable was P2Y12-I assignment. The primary outcome variable was death. Secondary outcomes included cardiovascular (CV) death, coronary revascularization, and gastrointestinal (GI) hemorrhage. Survival analyses were performed after propensity matching.

Results

Of 44,619 patients with ESKD who received P2Y12-Is, 95% received clopidogrel (n = 42,523), 3% prasugrel (n = 1205), and 2% ticagrelor (n = 891). To balance baseline differences, propensity-matching was performed: 1:6 for prasugrel (n = 1189) versus clopidogrel (n = 7134); 1:4 for ticagrelor (n = 880) versus clopidogrel (n = 3520); and 1:1 for ticagrelor versus prasugrel (n = 880). Prasugrel was associated with a reduced risk for death versus clopidogrel and ticagrelor (adjusted hazard ratio [HR] = 0.82; 95% CI: 0.73–0.93 and 0.78; 95% CI: 0.64–0.95). Compared with clopidogrel, prasugrel reduced risk for coronary revascularization (HR = 0.91; 95% CI: 0.86–0.96). There were no differences in GI hemorrhage between P2Y12-Is.

Conclusion

In patients with ESKD, prasugrel compared with others reduced risk of death possibly by reducing risk for coronary revascularizations and without worsening gastrointestinal hemorrhage. Future trials are imperative to compare efficacy and safety of P2Y12-Is in patients with ESKD.

Role of Platelets in Chronic Kidney Disease

Platelet-dependent mechanisms for excessive clotting and bleeding in CKD remain undefined. Moreover, platelets' contribution to inflammation, and specifically to CKD, are equally elusive. To date, descriptions of changes in the functional properties of circulating platelets during CKD have provided confusing interpretations. Experimental approaches that can advance our understanding of platelet dysfunction in CKD are needed, and studies that provide mechanistic insights into the dynamic relationships between thrombosis, bleeding, and inflammation associated with CKD will be essential to improve clinical management and outcomes for this vulnerable population. This article summarizes existing literature characterizing platelets in CKD and identifies areas that need further investigation.

Pros and cons of antithrombotic therapy in end-stage kidney disease: a 2019 update

Dialysis patients manifest both an increased thrombotic risk and a haemorrhagic tendency. A great number of patients with chronic kidney disease requiring dialysis have cardiovascular comorbidities (coronary artery disease, atrial fibrillation or venous thromboembolism) and different indications for treatment with antithrombotics (primary or secondary prevention). Unfortunately, few randomized controlled trials deal with antiplatelet and/or anticoagulant therapy in dialysis. Therefore cardiology and nephrology guidelines offer ambiguous recommendations and often exclude or ignore these patients. In our opinion, there is a need for an expert consensus that provides physicians with useful information to make correct decisions in different situations requiring antithrombotics. Herein the European Dialysis Working Group presents up-to-date evidence about the topic and encourages practitioners to choose among alternatives in order to limit bleeding and minimize atherothrombotic and cardioembolic risks. In the absence of clear evidence, these clinical settings and consequent therapeutic strategies will be discussed by highlighting data from observational studies for and against the use of antiplatelet and anticoagulant drugs alone or in combination. Until new studies shed light on unclear clinical situations, one should keep in mind that the objective of treatment is to minimize thrombotic risk while reducing bleeding events.

Trends for and Clinical Factors Associated with Choice of Oral P2Y12 Inhibitors for Patients on Chronic Dialysis

Background

Trends and clinical factors associated with prescribing choices for oral P2Y12 inhibitors (P2Y12-I) remain unknown for patients on chronic dialysis, i.e., with end-stage renal disease (ESRD).

Methods

From 2011–2014 U.S. Renal Data System registry, we identified 36,542 ESRD patients who received new prescriptions for P2Y12-I (median age 64.0 years and 54% males). Of the cohort, 93% were receiving hemodialysis and 7% on peritoneal dialysis. We analyzed trends and investigated clinical factors associated with specific P2Y12-I prescribed.

Results

Clopidogrel was prescribed for 95%, prasugrel for 3%, and ticagrelor for 2%. Clopidogrel was favored for those ≥75 years (18% of cohort). Compared to Caucasians, African Americans (36% of cohort) and Hispanics (19% of cohort) were less likely to receive prasugrel and ticagrelor (P<0.05). Patients receiving hemodialysis versus peritoneal dialysis were less likely to receive prasugrel over clopidogrel, adjusted odds ratio (aOR) 0.67 (0.55-0.82). Each additional year of dialysis decreased the odds of receiving prasugrel over clopidogrel, aOR 0.91 (0.85-0.98). History of atrial fibrillation reduced the odds of receiving ticagrelor or prasugrel over clopidogrel, aOR 0.69 (0.54-0.89) and 0.73 (0.60-0.89), respectively. Concomitant oral anticoagulant use was not associated with choice of P2Y12-I. Occurrence of non-ST segment elevation myocardial infarction or percutaneous coronary intervention within the 6-month period prior to the index date favored ticagrelor over prasugrel, aOR 1.31 (1.06-1.62) and 1.29 (1.01-1.66), respectively. However, prescribing trends favoring ticagrelor over prasugrel were not observed for deployment of drug-eluting, or multiple coronary stents.

Conclusion

Between 2011 and 2014, clopidogrel remained the most common P2Y12-I whereas ticagrelor and prasugrel remained underutilized in ESRD patients. Prescribing practices for these drugs were based upon clinically approved indication for their use in the general population as well as perceived complexity of an ESRD patient including demographics, dialysis-related factors and comorbidities. Comparative effectiveness studies involving ESRD patients are needed to prove that ticagrelor and prasugrel are just as safe and effective as clopidogrel before clinicians can make informed decisions for choice of P2Y12-I in this patient population.

Electronic supplementary material

The online version of this article (10.1007/s10557-019-06913-w) contains supplementary material, which is available to authorized users.