The Association of Sex with Unplanned Cardiac Readmissions following Percutaneous Coronary Intervention in Australia: Results from a Multicentre Outcomes Registry (GenesisCare Cardiovascular Outcomes Registry)

Background and aim: Unplanned cardiac readmissions in patients with percutaneous intervention (PCI) is very common and is seen as a quality indicator of in-hospital care. Most studies have reported on the 30-day cardiac readmission rates, with very limited information being available on 1-year readmission rates and their association with mortality. The aim of this study was to investigate the impact of biological sex at 1-year post-PCI on unplanned cardiac readmissions. Methods and results: Patients enrolled into the GenesisCare Cardiovascular Outcomes Registry (GCOR-PCI) from December 2008 to December 2020 were included in the study. A total of 13,996 patients completed 12 months of follow-up and were assessed for unplanned cardiac readmissions. All patients with unplanned cardiac readmissions in the first year of post-PCI were followed in year 2 (post-PCI) for survival status. The rate of unplanned cardiac readmissions was 10.1%. Women had a 29% higher risk of unplanned cardiac readmission (HR 1.29, 95% CI 1.11 to 1.48; p = 0.001), and female sex was identified as an independent predictor of unplanned cardiac readmissions. Any unplanned cardiac readmission in the first year was associated with a 2.5-fold higher risk of mortality (HR 2.50, 95% CI 1.67 to 3.75; p < 0.001), which was similar for men and women. Conclusion: Unplanned cardiac readmissions in the first year post-PCI was strongly associated with increased all-cause mortality. Whilst the incidence of all-cause mortality was similar between women and men, a higher incidence of unplanned cardiac readmissions was observed for women, suggesting distinct predictors of unplanned cardiac readmissions exist between women and men.

Antithrombotic Therapy for Chronic Kidney Disease Patients With Concomitant Atrial Fibrillation and Coronary Artery Disease

Background: Oral anticoagulants (OAC) plus antiplatelets is recommended for patients with atrial fibrillation (AF) and coronary artery disease (CAD) to reduce thromboembolism. However, there is limited evidence regarding antithrombotic therapy for patients with concomitant chronic kidney disease (CKD), AF, and CAD, especially those not undergoing percutaneous coronary intervention. We aimed to use real-world data assessing the efficacy and safety of antithrombotic regimens in this population.

Methods: We used a single-center database of 142,624 CKD patients to identify those receiving antithrombotic therapy for AF and CAD between 2010 and 2018. Patients taking warfarin or direct OAC (DOAC) alone were grouped in the OAC monotherapy (n = 537), whereas those taking OAC plus antiplatelets were grouped in the combination therapy (n = 2,391). We conducted propensity score matching to balance baseline covariates. The endpoints were all-cause mortality, major adverse cardiovascular events, and major bleedings.

Results: After 1:4 matching, the number of patients in OAC monotherapy and combination therapy were 413 and 1,652, respectively. Between the two groups, combination therapy was associated with higher risks for ischemic stroke (HR 2.37, CI 1.72–3.27), acute myocardial infarction (HR 6.14, CI 2.51–15.0), and hemorrhagic stroke (HR 3.57, CI 1.35–9.81). The results were consistent across CKD stages. In monotherapy, DOAC users were associated with lower risks for all-cause mortality, AMI, and gastrointestinal bleeding than warfarin, but the stroke risk was similar between the two subgroups.

Conclusions: For patients with concomitant CKD, AF and CAD not undergoing PCI, OAC monotherapy may reduce stroke and AMI risks. DOAC showed more favorable outcomes than warfarin.

Impact Of Chronic Kidney Disease On The Pharmacodynamic And Pharmacokinetic Effects Of Ticagrelor In Patients With Diabetes Mellitus And Coronary Artery Disease

AIMS

Patients with diabetes mellitus (DM) and chronic kidney disease (CKD) are at increased risk of atherothrombotic events. Ticagrelor reduces ischaemic events compared to clopidogrel, with the greatest risk reduction in patients with both DM and CKD. How CKD status affects the pharmacodynamic (PD) and pharmacokinetic (PK) profiles of different ticagrelor maintenance dose regimens in patients with DM is unknown.

METHODS AND RESULTS

In this randomized, cross-over study, patients with DM on treatment with dual antiplatelet therapy (aspirin and clopidogrel) were stratified according to CKD status and randomized to ticagrelor 90 mg bid or 60 mg bid. PK/PD assessments were performed at baseline, after 7-10 days of ticagrelor (peak and trough), and after 7-10 days of alternative ticagrelor regimen (peak and trough). PK assessments included plasma concentrations of ticagrelor and its major metabolite. PD assessments included VASP-PRI, VerifyNow P2Y12, and LTA.A total of 92 patients with DM (CKD, n = 44; non-CKD, n = 48) were randomized. Levels of platelet reactivity were lower with the 90 mg compared with the 60 mg ticagrelor dose, which was statistically significant in non-CKD but not in CKD patients for most PD measures. There were no significant differences in the primary endpoint (trough levels of VASP-PRI following ticagrelor 90 mg dosing) between cohorts (31 ± 20 vs 25 ± 14; p = 0.105). VerifyNow and LTA provided similar findings. PK assessments tracked PD profiles showing increased plasma concentrations of ticagrelor and its major metabolite in CKD compared to non-CKD patients.

CONCLUSION

In patients with DM, although ticagrelor maintenance dose regimens (60 mg and 90 mg) yield potent P2Y12 inhibition, levels of platelet reactivity tended to be higher and subject to broader variability in non-CKD compared with CKD patients.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov Unique Identifier: NCT02539160.

Impact of chronic kidney disease on platelet aggregation in patients with acute coronary syndrome

AIMS

Chronic kidney disease (CKD) is associated with increased thrombotic events and seems to influence platelet reactivity. Conflicting results have been published on platelet response in CKD patients with stable coronary artery disease. The aim of our study was to investigate the impact of CKD on platelet aggregation in acute coronary syndrome (ACS) patients receiving dual antiplatelet therapy, included the more potent P2Y12 inhibitors.

METHODS

We enrolled 206 patients with ACS, divided in two groups, according to the presence or the absence of moderate/severe CKD. Platelet aggregation was performed with light transmission aggregometry and results are expressed as percentage of maximum platelet aggregation. High residual platelet reactivity (HRPR) was defined as maximum platelet aggregation more than 59%.

RESULTS

Patients with CKD [estimate glomerular filtration rate (eGFR) < 60 ml/min/1.73 m, n = 28] were prevalent older, diabetic, had previous coronary revascularization. In these patients, platelet aggregation was significantly higher than in those with eGFR ≥ 60 ml/min/1.73 m (ADP 10 μmol/l: 28.46 ± 26.19 vs. 16.64 ± 12.79, P < 0.001; ADP 20 μmol/l: 30.07 ± 25.89 vs. 17.46 ± 12.82, P < 0.001). HRPR was observed in 4.4% of patients, with higher prevalence in those with eGFR less than 60 ml/min/1.73 m [21.4 vs. 1.7%, P < 0.001, odds ratio (OR) [95% confidence interval (CI)] = 15.91 (3.71-68.17), P < 0.001]. At multivariate analysis, after correction for baseline confounders, eGFR [adjusted OR (95% CI) = 0.95 (0.91-0.98), P = 0.007], together with the use of clopidogrel [adjusted OR (95% CI) = 23.59 (4.01-138.82), P < 0.001], emerged as determinants of HRPR.

CONCLUSION

In patients with ACS receiving dual antiplatelet therapy, CKD is associated with an increasing ADP-induced platelet aggregation and higher prevalence of HRPR, which is mainly correlated to clopidogrel use.

Impact of Chronic Kidney Disease and Platelet Reactivity on Clinical Outcomes Following Percutaneous Coronary Intervention

We investigated the interaction between chronic kidney disease (CKD) and high platelet reactivity (HPR) in determining long-term clinical outcomes following elective PCI for stable coronary artery disease (CAD). A total of 500 patients treated with aspirin and clopidogrel were divided based on the presence of CKD (defined as glomerular filtration rate of < 60 ml/min/1.73 m²) and HPR (defined as a P2Y12 reaction unit value ≥ 240 at VerifyNow assay). Primary endpoint was the occurrence of major adverse clinical events (MACE) at 5 years. Patients with both CKD and HPR showed the highest estimates of MACE (25.6%, p = 0.005), all-cause death (17.9%, p = 0.004), and cardiac death (7.7%, p = 0.004). The combination of CKD and HPR was an independent predictor of MACE (HR 3.12, 95% CI 1.46-6.68, p = 0.003). In conclusion, the combination of CKD and HPR identifies a cohort of patients with the highest risk of MACE at 5 years.

TicagRelor Or Clopidogrel in severe or terminal chronic kidney patients Undergoing PERcutaneous coronary intervention for acute coronary syndrome: The TROUPER trial

Chronic kidney disease (CKD) is associated with an increased risk of acute coronary syndrome (ACS) and cardiovascular death. CKD patients suffering from ACS are exposed to an increased risk of thrombotic recurrences and a higher bleeding rate than patients with normal renal function. However, CKD patients are excluded or underrepresented in clinical trials. Therefore, determining the optimal antiplatelet strategy in this population is of utmost importance. We designed the TicagRelor Or Clopidogrel in severe or terminal chronic kidney patients Undergoing PERcutaneous coronary intervention for acute coronary syndrome (TROUPER) trial: a prospective, controlled, multicenter, randomized trial to investigate the optimal P2Y12 antagonist in CKD patients with ACS. Patients with stage ≥3b CKD are eligible if the diagnosis of ACS is made and invasive strategy scheduled. Patients are randomized 1:1 between a control group with a 600-mg loading dose of clopidogrel followed by a 75-mg/d maintenance dose for 1 year and an experimental group with a 180-mg loading dose of ticagrelor followed by a 90-mg twice daily maintenance dose for the same duration. The primary end point is defined by the rate of major adverse cardiovascular events, including death, myocardial infarction, urgent revascularization, and stroke at 1 year. Safety will be evaluated by the bleeding rate (Bleeding Academic Research Consortium). To demonstrate the superiority of ticagrelor on major adverse cardiovascular events, we calculated that 508 patients are required. The aim of the TROUPER trial is to compare the efficacy of ticagrelor and clopidogrel in stage >3b CKD patients presenting with ACS and scheduled for an invasive strategy. RCT# NCT03357874.

Platelet activity with hemoglobin level in patients with hemodialysis: Prospective study

BACKGROUND

VerifyNow (VN; Accumetrics, San Diego, CA) P2Y12 reaction unit (PRU) has an inverse relation with hemoglobin level (Hb). Chronic kidney disease (CKD) is associated with low response to clopidogrel and low Hb. Our aim is to investigate the relation between PRU and Hb, and to assess whether Hb directly affects PRU or not in patients with CKD undergoing hemodialysis (HD).

METHODS

We analyzed the relation between PRU and Hb in 43 HD patients and compared it with a control group of 127 patients with normal renal function. Both groups underwent percutaneous coronary intervention for stable coronary artery disease. We also compared PRU between the 2 groups considering Hb as a confounding factor.

RESULTS

In the control group, Hb and PRU showed a significant inverse correlation (correlation coefficient r = -0.340; P < .001), but not in the HD group (correlation coefficient r = -0.099; P = .53). PRU was higher in the HD group than the control group after adjusting for the influence of Hb (299.2 [95% confidence interval: 278.4-316.7] vs 248.7 [95% confidence interval: 227.7-269.0]; P < .001), even after propensity score matching (299.2 [95% confidence interval: 278.4-316.7] vs 241.7 [95% confidence interval: 221.8-262.2]; P < .001).

CONCLUSIONS

PRU was higher regardless of lower Hb in CKD on HD patients than normal renal function patients. Therefore, Hb was not crucial factor to decide PRU in CKD on HD patients in this study.

Prognostic Value of Incomplete Revascularization after Percutaneous Coronary Intervention Following Acute Coronary Syndrome: Focus on CKD Patients

Background: Residual coronary artery disease (CAD) has been associated with worsened prognosis in patients undergoing percutaneous coronary intervention (PCI) for acute coronary syndromes (ACS). The residual SYNTAX Score (rSS) aims to assess residual CAD after PCI. The association between kidney function and rSS has not been investigated in ACS patients. In this study, we sought to determine whether chronic kidney disease (CKD) patients exhibit more incomplete revascularization following stage revascularization procedures by PCI. We evaluated the impact of incomplete revascularization on the occurrence of major cardiovascular events (MACE) at one-year follow-up. Methods: A total of 831 ACS patients undergoing PCI were divided into 3 subgroups according to their estimated Glomerular Filtration Rate (eGFR): 695 with eGFR ≥ 60 mL/min/1.73 m², 108 with eGFR 60–30 mL/min/1.73 m², 28 with eGFR < 30 mL/min/1.73 m². Initial SYNTAX score (SS) and rSS were calculated for all patients. Incomplete revascularization was defined by rSS > 8. The primary endpoint was the occurrence of MACE (all-cause mortality, myocardial infarction (MI), repeated revascularization except from planned revascularization, stroke and definite or probable recurrent stent thrombosis) one year after the index procedure. Results: Severe CKD patients had significantly higher MACE (12.0% vs. 25.9% vs. 35.7%; p < 0.001), all-cause mortality, cardiovascular mortality and heart failure events. Patients with rSS > 8 had higher MACE, all-cause and cardiovascular mortality. CKD was an independent predictive factor of rSS > 8 (HR: 1.65, 95% CI: 1.01 to 2.71; p = 0.048). Multivariate analysis identified rSS > 8, but not CKD, as an independent predictor of cardiac death and MACE. Conclusion: In ACS, CKD is predictive of incomplete revascularization, which stands out as a strong predictor of adverse cardiovascular outcomes including cardiac death and MACE.

Oral Antiplatelet Therapy for Secondary Prevention of Acute Coronary Syndrome

Patients surviving an acute coronary syndrome (ACS) remain at increased risk of ischemic events long term. This paper reviews current evidence and guidelines for oral antiplatelet therapy for secondary prevention following ACS, with respect to decreased risk of ischemic events versus bleeding risk according to individual patient characteristics and risk factors. Specifically, data are reviewed from clinical studies of clopidogrel, prasugrel, ticagrelor and vorapaxar, as well as the results of systematic reviews and meta-analyses looking at the benefits and risks of oral antiplatelet therapy, and the relative merits of shorter versus longer duration of dual antiplatelet therapy, in different patient groups.

Effects of statin therapy on platelet reactivity after percutaneous coronary revascularization in patients with acute coronary syndrome

Statin use is associated with enhanced pharmacodynamic response to clopidogrel in patients with stable coronary artery disease undergoing percutaneous coronary intervention (PCI). However, the impact of statin therapy on clopidogrel response profiles in patients with acute coronary syndrome (ACS) undergoing PCI has not been established and represents the objective of this investigation. On-treatment P2Y₁₂ platelet reactivity was measured using the vasodilator stimulated phosphoprotein (VASP) phosphorylation assay before PCI, at hospital discharge, and at 1 month after PCI in ACS patients enrolled in the multicenter, prospective GEne polymorphisms, Platelet Reactivity, and Syntax Score (GEPRESS) study (n = 962). High platelet reactivity (HPR) was defined as platelet reactivity index ≥50%. Statins were prescribed at hospital discharge in 87% (n = 835) of patients. All patients were followed for 1 year. The 1-month HPR rate was lower in statin than in non-statin treated patients (39.6 vs 52%, respectively, p = 0.009). This finding was confirmed also among statin-treated patients with high Syntax score (≥15). After adjustment for differences in baseline characteristics, statin use at discharge was independently associated with 1-month HPR rate (odds ratio, 0.58, 95% confidence interval, 0.38-0.89; p = 0.015). In ACS patients undergoing PCI treated with clopidogrel the use of statins at discharge was associated with significantly lower 1-month HPR rates compared with patients not treated with statins.

Impact of chronic kidney disease on platelet P2Y12 receptor signalling in patients with type 2 diabetes mellitus

Supplementary Material to this article is available online at www.thrombosis-online.com.

The impact of renal function on platelet reactivity and clinical outcome in patients undergoing percutaneous coronary intervention with stenting

Patients with chronic kidney disease (CKD) have an increased risk of cardiovascular disease. Previous studies have suggested that patients with CKD have less therapeutic benefit of antiplatelet therapy. However, the relation between renal function and platelet reactivity is still under debate. On-treatment platelet reactivity was determined in parallel by ADP- and AA-induced light transmittance aggregometry (LTA) and the VerifyNow® System (P2Y12 and Aspirin) in 988 patients on dual antiplatelet therapy, undergoing elective coronary stenting. Patients were divided into two groups according to the presence or absence of moderate/severe CKD (GFR<60 ml/min/1.73 m2). Furthermore, the incidence of all-cause death, non-fatal acute myocardial infarction, stent thrombosis and stroke at one-year was evaluated. Patients with CKD (n=180) had significantly higher platelet reactivity, regardless of the platelet function test used. Patients with CKD more frequently had high on-clopidogrel platelet reactivity (HCPR) and high on-aspirin platelet reactivity (HAPR) regardless of the platelet function test used. After adjustment for potential confounders, this was no longer significant. The event-rate was the highest in patients with both high on-treatment platelet reactivity (HPR) and CKD compared to those with neither high on-treatment platelet reactivity nor CKD. In conclusion, the magnitude of platelet reactivity as well as the incidence of HPR was higher in patients with CKD. However, since the incidence of HPR was similar after adjustment, a higher rate of co-morbidities in patients with CKD might be the major cause for this observation rather than CKD itself. CKD-patients with HCPR were at the highest risk of long-term cardiovascular events.

Clinical Trial Registration: www.clinicaltrials.gov: NCT00352014.

Role of P2Y12 Receptor in Thrombosis

P2Y₁₂ receptor is a 342 amino acid Gi-coupled receptor predominantly expressed on platelets. P2Y₁₂ receptor is physiologically activated by ADP and inhibits adenyl cyclase (AC) to decrease cyclic AMP (cAMP) level, resulting in platelet aggregation. It also activates PI3 kinase (PI3K) pathway leading to fibrinogen receptor activation, and may protect platelets from apoptosis. Abnormalities of P2Y₁₂ receptor include congenital deficiencies or high activity in diseases like diabetes mellitus (DM) and chronic kidney disease (CKD), exposing such patients to a prothrombotic condition. A series of clinical antiplatelet drugs, such as clopidogrel and ticagrelor, are designed as indirect or direct antagonists of P2Y₁₂ receptor to reduce incidence of thrombosis mainly for patients of acute coronary syndrome (ACS) who are at high risk of thrombotic events. Studies on novel dual-/multi-target antiplatelet agents consider P2Y₁₂ receptor as a promising part in combined targets. However, the clinical practical phenomena, such as "clopidogrel resistance" due to gene variations of cytochrome P450 or P2Y₁₂ receptor constitutive activation, call for better antiplatelet agents. Researches also showed inverse agonist of P2Y₁₂ receptor could play a better role over neutral antagonists. Personalized antiplatelet therapy is the most ideal destination for antiplatelet therapy in ACS patients with or without other underlying diseases like DM or CKD, however, there is still a long way to go.

Post Hoc Analyses of Randomized Clinical Trial for the Effect of Clopidogrel Added to Aspirin on Kidney Function

BACKGROUND AND OBJECTIVES

Despite the high burden of CKD, few specific therapies are available that can halt disease progression. In animal models, clopidogrel has emerged as a potential therapy to preserve kidney function. The effect of clopidogrel on kidney function in humans has not been established.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Secondary Prevention of Small Subcortical Strokes Study randomized participants with prior lacunar stroke to treatment with aspirin or aspirin plus clopidogrel. We compared annual eGFR decline and incidence of rapid eGFR decline (≥30% from baseline) using generalized estimating equations and interval-censored proportional hazards regression, respectively. We also stratified our analyses by baseline eGFR, systolic BP target, and time after randomization.

RESULTS

At randomization, median age was 62 (interquartile range, 55-71) years old; 36% had a history of diabetes, 90% had hypertension, and the median eGFR was 81 (interquartile range, 65-94) ml/min per 1 m2. Persons receiving aspirin plus clopidogrel had an average annual change in kidney function of -1.39 (95% confidence interval, -1.15 to -1.62) ml/min per 1.73 m2 per year compared with -1.52 (95% confidence interval, -1.30 to -1.74) ml/min per 1.73 m2 per year among persons receiving aspirin only (P=0.42). Rapid kidney function decline occurred in 21% of participants receiving clopidogrel plus aspirin compared with 22% of participants receiving aspirin plus placebo (hazard ratio, 0.94; 95% confidence interval, 0.79 to 1.10; P=0.42). Findings did not vary by baseline eGFR, time after randomization, or systolic BP target (all P values for interaction were >0.3).

CONCLUSIONS

We found no effect of clopidogrel added to aspirin compared with aspirin alone on kidney function decline among persons with prior lacunar stroke.

Oral antiplatelet therapy and platelet inhibition: An experience from a tertiary care center

AIMS AND OBJECTIVES

Although clopidogrel combined with aspirin is the most commonly used dual drug combination to avert thrombotic events in patients with coronary artery disease, the poor responsiveness to clopidogrel remains a concern. The objective of the current study is to assess the extent of resistance to clopidogrel, prasugrel, and ticagrelor in a real life set of patients with coronary artery disease who underwent percutaneous coronary intervention (PCI).

MATERIALS AND METHODS

A total of 539 patients, who underwent PCI and were on aspirin and on any of the three drugs, namely, clopidogrel, prasugrel and ticagrelor, were followed up regularly in the outpatient department. After 24h of initiation of antiplatelet medication, response to the treatment in all the patients was assessed using thrombelastography. The average percentage platelet inhibition was assessed along with the resistance and sensitivity to the drug in each patient. Sensitivity and resistance to the specific drug was defined as >50% and <50% of mean platelet inhibition, respectively.

RESULTS

About 99.15% of the patients treated with ticagrelor were sensitive to the drug and the difference between ticagrelor, clopidogrel, and prasugrel groups for sensitivity was significant with a p value of 0.00001, in favor of ticagrelor. It was also found that ticagrelor was significantly (p value of 0.001) associated with least resistance as compared with the other drugs assessed in the study.

CONCLUSIONS

Use of ticagrelor as dual therapy along with aspirin in patients with coronary artery disease (CAD) and undergoing PCI was associated with a significantly higher mean percentage platelet inhibition, higher sensitivity, and lower resistance as compared with the usage of clopidogrel or prasugrel.

High On-Treatment Platelet Reactivity in Peripheral Arterial Disease: A Pilot Study to Find the Optimal Test and Cut Off Values

OBJECTIVE

Restenosis and stent thrombosis after endovascular intervention in patients with peripheral arterial disease (PAD) can potentially be tackled by more intensive antiplatelet therapy, such as dual antiplatelet therapy (DAPT) consisting of aspirin and P2Y12 inhibitor. Despite clopidogrel treatment, some patients still display high platelet reactivity (HCPR). Tailored antiplatelet therapy, based on platelet reactivity testing, might overcome HCPR. However, more data are warranted regarding the proportion of patients with HCPR in the PAD population, different platelet reactivity tests, their correlation, and the optimal timing for these tests as a stepping stone for a future trial investigating the potential benefit of tailored antiplatelet therapy in PAD patients.

METHODS

Thirty patients on DAPT after percutaneous transluminal angioplasty underwent platelet reactivity testing by VerifyNow, vasodilator-stimulated phosphoprotein (VASP) and platelet activation assay, and CYP2C19-polymorphism testing.

RESULTS

The proportion of patients with HCPR measured by VerifyNow varied between 43.3% and 83.3%, depending on the cut off values used. Testing within 24 hours of initiation of DAPT gave a higher proportion of HCPR than testing after more than 24 hours. According to DNA testing, 14.8% were CYP2C19*2 homozygote, 22.2% heterozygote, and 63% CYP2C19*2 negative. VASP assay revealed 24% HCPR. The highest HCPR rate was found with a VerifyNow cut off of less than 40% inhibition, whereas the lowest HCPR rate was found with the VASP assay. There was a low correlation between the tests.

CONCLUSION

HCPR is present in PAD patients and research on HCPR is needed in this population; timing of tests is relevant and standardisation of tests is needed. The optimal conditions for platelet function testing should be determined.

P2Y12 Receptor Localizes in the Renal Collecting Duct and Its Blockade Augments Arginine Vasopressin Action and Alleviates Nephrogenic Diabetes Insipidus

P2Y12 receptor (P2Y12-R) signaling is mediated through Gi, ultimately reducing cellular cAMP levels. Because cAMP is a central modulator of arginine vasopressin (AVP)-induced water transport in the renal collecting duct (CD), we hypothesized that if expressed in the CD, P2Y12-R may play a role in renal handling of water in health and in nephrogenic diabetes insipidus. We found P2Y12-R mRNA expression in rat kidney, and immunolocalized its protein and aquaporin-2 (AQP2) in CD principal cells. Administration of clopidogrel bisulfate, an irreversible inhibitor of P2Y12-R, significantly increased urine concentration and AQP2 protein in the kidneys of Sprague-Dawley rats. Notably, clopidogrel did not alter urine concentration in Brattleboro rats that lack AVP. Clopidogrel administration also significantly ameliorated lithium-induced polyuria, improved urine concentrating ability and AQP2 protein abundance, and reversed the lithium-induced increase in free-water excretion, without decreasing blood or kidney tissue lithium levels. Clopidogrel administration also augmented the lithium-induced increase in urinary AVP excretion and suppressed the lithium-induced increase in urinary nitrates/nitrites (nitric oxide production) and 8-isoprostane (oxidative stress). Furthermore, selective blockade of P2Y12-R by the reversible antagonist PSB-0739 in primary cultures of rat inner medullary CD cells potentiated the expression of AQP2 and AQP3 mRNA, and cAMP production induced by dDAVP (desmopressin). In conclusion, pharmacologic blockade of renal P2Y12-R increases urinary concentrating ability by augmenting the effect of AVP on the kidney and ameliorates lithium-induced NDI by potentiating the action of AVP on the CD. This strategy may offer a novel and effective therapy for lithium-induced NDI.

Post receptor determinants of acute platelet response to clopidogrel in patients with symptomatic myocardial ischemia

BACKGROUND

Clopidogrel resistance is more common in patients with loss-of-function CYP2C19 genotypes. Since adenylate cyclase (AC) and soluble guanylate cyclase (sGC) pathways are variably impaired in patients with ischaemic heart disease, we tested the relevance of these determinants in patients undergoing acute loading with clopidogrel (600 mg) prior to non-emergent coronary stenting.

METHODS

Inhibitory effects of prostaglandin E1 (PGE1, an AC activator) and sodium nitroprusside (NP, a sGC activator) on platelet aggregation were determined at baseline and compared with platelet responses to clopidogrel (4 h after administration) assessed as ∆ADP, and Platelet Reactivity Index (∆PRI). Data were analysed according to CYP2C19 genotype.

RESULTS

In patients without loss of function mutations (n=18), ∆ADP but not ∆PRI, was directly correlated with baseline PGE1 responsiveness (rs=0.62, p=0.005)). NP responsiveness did not predict ∆ADP. However there was no relationship between clopidogrel responses and either PGE1 or NP responsiveness in patients with loss of function mutations. Multivariate correlates of clopidogrel response were both the genotype status (β=-0.609, p<0.001) and the baseline response to PGE1 (β=0.303, p=0.03).

CONCLUSIONS

While genetically impaired bio-activation markedly limits acute (4 h) clopidogrel response, impaired AC signalling provides an additional cause for clopidogrel resistance.

Incidence and impact on prognosis of bleeding during percutaneous coronary interventions in patients with chronic kidney disease

BACKGROUND

Limited information exists on the prognostic impact of bleeding after percutaneous coronary intervention (PCI) in patients with chronic kidney disease (CKD). We investigated the impact of bleeding after PCI on the outcome of these patients.

METHODS

The study included 2,934 patients with estimated creatinine clearance <60 ml/min. Bleeding events within 30 days after PCI were assessed using the Bleeding Academic Research Consortium (BARC) criteria. The primary outcome was 1-year mortality.

RESULTS

Bleeding events occurred in 485 patients (16.5 %). BARC classes were: class 1 (n = 155), class 2 (n = 73), class 3a (n = 182), class 3b (n = 68), class 3c (n = 6) and class 4 (n = 1). There were 212 deaths over the first year after PCI: 60 deaths in patients who bled and 152 deaths in patients who did not bleed (Kaplan-Meier [KM] estimates, 12.5 and 6.3 %; odds ratio [OR] = 2.11, 95 % confidence interval [CI] 1.57-2.83, P < 0.001). Nonfatal myocardial infarction occurred in 71 patients who bled and in 141 patients who did not bleed (KM estimates, 14.8 and 5.8 %; OR = 2.70 [2.05-3.55], P < 0.001). After adjustment, bleeding was independently associated with increased risk of 1-year mortality (adjusted hazard ratio [HR] = 1.90 [1.33-2.72], P < 0.001) and myocardial infarction (adjusted HR = 2.74 [1.99-3.78], P < 0.001). Bleeding improved the discriminatory power of the multivariable model for prediction of mortality (absolute and relative integrated discrimination improvement [IDI], 0.011 and 15.4 %; P = 0.004) or myocardial infarction (absolute and relative IDI, 0.017 and 70.8 %; P < 0.001).

CONCLUSIONS

Peri-PCI bleeding in patients with CKD is independently associated with the increased risk of 1-year mortality and nonfatal myocardial infarction.