Long-Term Cost Effectiveness of Early and Sustained Dual Oral Antiplatelet Therapy With Clopidogrel Given for Up to One Year After Percutaneous Coronary Intervention

Antiplatelet agents for chronic kidney disease

BACKGROUND

Antiplatelet agents are widely used to prevent cardiovascular events. The risks and benefits of antiplatelet agents may be different in people with chronic kidney disease (CKD) for whom occlusive atherosclerotic events are less prevalent, and bleeding hazards might be increased. This is an update of a review first published in 2013.

OBJECTIVES

To evaluate the benefits and harms of antiplatelet agents in people with any form of CKD, including those with CKD not receiving renal replacement therapy, patients receiving any form of dialysis, and kidney transplant recipients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 13 July 2021 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We selected randomised controlled trials of any antiplatelet agents versus placebo or no treatment, or direct head-to-head antiplatelet agent studies in people with CKD. Studies were included if they enrolled participants with CKD, or included people in broader at-risk populations in which data for subgroups with CKD could be disaggregated.

DATA COLLECTION AND ANALYSIS

Four authors independently extracted data from primary study reports and any available supplementary information for study population, interventions, outcomes, and risks of bias. Risk ratios (RR) and 95% confidence intervals (CI) were calculated from numbers of events and numbers of participants at risk which were extracted from each included study. The reported RRs were extracted where crude event rates were not provided. Data were pooled using the random-effects model. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included 113 studies, enrolling 51,959 participants; 90 studies (40,597 CKD participants) compared an antiplatelet agent with placebo or no treatment, and 29 studies (11,805 CKD participants) directly compared one antiplatelet agent with another. Fifty-six new studies were added to this 2021 update. Seven studies originally excluded from the 2013 review were included, although they had a follow-up lower than two months. Random sequence generation and allocation concealment were at low risk of bias in 16 and 22 studies, respectively. Sixty-four studies reported low-risk methods for blinding of participants and investigators; outcome assessment was blinded in 41 studies. Forty-one studies were at low risk of attrition bias, 50 studies were at low risk of selective reporting bias, and 57 studies were at low risk of other potential sources of bias. Compared to placebo or no treatment, antiplatelet agents probably reduces myocardial infarction (18 studies, 15,289 participants: RR 0.88, 95% CI 0.79 to 0.99, I² = 0%; moderate certainty). Antiplatelet agents has uncertain effects on fatal or nonfatal stroke (12 studies, 10.382 participants: RR 1.01, 95% CI 0.64 to 1.59, I² = 37%; very low certainty) and may have little or no effect on death from any cause (35 studies, 18,241 participants: RR 0.94, 95 % CI 0.84 to 1.06, I² = 14%; low certainty). Antiplatelet therapy probably increases major bleeding in people with CKD and those treated with haemodialysis (HD) (29 studies, 16,194 participants: RR 1.35, 95% CI 1.10 to 1.65, I² = 12%; moderate certainty). In addition, antiplatelet therapy may increase minor bleeding in people with CKD and those treated with HD (21 studies, 13,218 participants: RR 1.55, 95% CI 1.27 to 1.90, I² = 58%; low certainty). Antiplatelet treatment may reduce early dialysis vascular access thrombosis (8 studies, 1525 participants) RR 0.52, 95% CI 0.38 to 0.70; low certainty). Antiplatelet agents may reduce doubling of serum creatinine in CKD (3 studies, 217 participants: RR 0.39, 95% CI 0.17 to 0.86, I² = 8%; low certainty). The treatment effects of antiplatelet agents on stroke, cardiovascular death, kidney failure, kidney transplant graft loss, transplant rejection, creatinine clearance, proteinuria, dialysis access failure, loss of primary unassisted patency, failure to attain suitability for dialysis, need of intervention and cardiovascular hospitalisation were uncertain. Limited data were available for direct head-to-head comparisons of antiplatelet drugs, including prasugrel, ticagrelor, different doses of clopidogrel, abciximab, defibrotide, sarpogrelate and beraprost.

AUTHORS' CONCLUSIONS

Antiplatelet agents probably reduced myocardial infarction and increased major bleeding, but do not appear to reduce all-cause and cardiovascular death among people with CKD and those treated with dialysis. The treatment effects of antiplatelet agents compared with each other are uncertain.

The Role of Clopidogrel in 2020: A Reappraisal

Antiplatelet therapy is the mainstay of treatment and secondary prevention of cardiovascular disease (CVD), including acute coronary syndrome (ACS), transient ischemic attack (TIA) or minor stroke, and peripheral artery disease (PAD). The P2Y12 inhibitors, of which clopidogrel was the first, play an integral role in antiplatelet therapy and therefore in the treatment and secondary prevention of CVD. This review discusses the available evidence concerning antiplatelet therapy in patients with CVD, with a focus on the role of clopidogrel. In combination with aspirin, clopidogrel is often used as part of dual antiplatelet therapy (DAPT) for the secondary prevention of ACS. Although newer, more potent P2Y12 inhibitors (prasugrel and ticagrelor) show a greater reduction in ischemic risk compared with clopidogrel in randomized trials of ACS patients, these newer P2Y12 inhibitors are often associated with an increased risk of bleeding. Deescalation of DAPT by switching from prasugrel or ticagrelor to clopidogrel may be required in some patients with ACS. Furthermore, real-world studies of ACS patients have not confirmed the benefits of the newer P2Y12 inhibitors over clopidogrel. In patients with very high-risk TIA or stroke, short-term DAPT with clopidogrel plus aspirin for 21-28 days, followed by clopidogrel monotherapy for up to 90 days, is recommended. Clopidogrel monotherapy may also be used in patients with symptomatic PAD. In conclusion, there is strong evidence supporting the use of clopidogrel antiplatelet therapy in several clinical settings, which emphasizes the importance of this medication in clinical practice.

Quality of health economic evaluations for the ACC/AHA stable ischemic heart disease practice guideline: A systematic review

BACKGROUND

The American College of Cardiology/American Heart Association (ACC/AHA) recently published a rigorous framework to guide integration of economic data into clinical guidelines. We assessed the quality of economic evaluations in a major ACC/AHA clinical guidance report.

METHODS

We systematically identified cost-effectiveness analyses (CEAs) of RCTs cited in the ACC/AHA 2012 Guideline for the Diagnosis and Management of Patients with Stable Ischemic Heart Disease. We extracted: (1) study identifiers; (2) parent RCT information; (3) economic analysis characteristics; and (4) study quality using the Quality of Health Economic Studies instrument (QHES).

RESULTS

Quality scores were categorized as high (≥75 points) or low (<75 points). Of 1,266 citations in the guideline, 219 were RCTs associated with 77 CEAs. Mean quality score was 81 (out of 100) and improved over time, though 29.9% of studies were low-quality. Cost-per-QALY was the most commonly reported primary outcome (39.0%). Low-quality studies were less likely to report study perspective, use appropriate time horizons, or address statistical and clinical uncertainty. Funding was overwhelmingly private (83%). A detailed methodological assessment of high-quality studies revealed domains of additional methodological issues not identified by the QHES.

CONCLUSIONS

Economic evaluations of RCTs in the 2012 ACC/AHA ischemic heart disease guideline largely had high QHES scores but methodological issues existed among "high-quality" studies. Because the ACC/AHA has generally been more systematic in its integration of scientific evidence compared to other professional societies, it is likely that most societies will need to proceed more cautiously in their integration of economic evidence.

Prior chronic clopidogrel therapy is associated with increased adverse events and early stent thrombosis

Despite the growing use of clopidogrel, limited data exist regarding the prognostic significance of chronic clopidogrel therapy in patients sustaining acute coronary syndrome (ACS). Our aim was to determine whether patients sustaining ACS while on chronic clopidogrel therapy have a worse prognosis than clopidogrel-naïve patients. A total of 5,386 consecutive ACS patients were prospectively characterised and followed-up for 30 days. Of them, 680 (13 %) were treated with clopidogrel prior to the index ACS. Major adverse cardiovascular events (MACE) were defined as death, recurrent ACS, stroke and/or stent thrombosis. Compared with clopidogrel-naïve, chronic clopidogrel-treated patients were older (66 ± 12 vs 63 ± 13, respectively; p< 0.01), suffered more from diabetes mellitus, hypertension, dyslipidaemia, prior cardiovascular history, including prior myocardial infarction, revascularisation, coronary artery bypass graft and stroke (p< 0.01 for all), and were less likely to present with ST-elevation myocardial infarction (21 % vs 45 %; respectively; p < 0.001). Prior clopidogrel therapy was associated with a two-fold increase in in-hospital (1.6 °% vs 0.6, respectively; p =0.006) as well as 30-day stent thrombosis (2.2 % vs 1.0 %, respectively; p=0.007). MACE at 30 days was also higher among chronic clopidogrel-treated compared with clopidogrel-naïve patients [12.3 % vs 9.4 %, respectively; p< 0.01]. In multivariate log regression analysis chronic clopidogrel treatment was an independent predictor of stent thrombosis [OR=2.6 (95 %CI 1.2–5.6), p=0.001]. Patients sustaining ACS while on chronic clopidogrel treatment are at higher risk for in-hospital and 30-day adverse outcomes, including stent thrombosis.

Reducing the Global Burden of Cardiovascular Disease, Part 2: Prevention and Treatment of Cardiovascular Disease

In this second part of a 2-part series on the global burden of cardiovascular disease, we review the proven, effective approaches to the prevention and treatment of cardiovascular disease. We specifically review the management of acute cardiovascular diseases, including acute coronary syndromes and stroke; the care of cardiovascular disease in the ambulatory setting, including medical strategies for vascular disease, atrial fibrillation, and heart failure; surgical strategies for arterial revascularization, rheumatic and other valvular heart disease, and symptomatic bradyarrhythmia; and approaches to the prevention of cardiovascular disease, including lifestyle factors, blood pressure control, cholesterol-lowering, antithrombotic therapy, and fixed-dose combination therapy. We also discuss cardiovascular disease prevention in diabetes mellitus; digital health interventions; the importance of socioeconomic status and universal health coverage. We review building capacity for conduction cardiovascular intervention through strengthening healthcare systems, priority setting, and the role of cost effectiveness.

Haplotype of platelet receptor P2RY12 gene is associated with residual clopidogrel on-treatment platelet reactivity

OBJECTIVE

To investigate a possible association between common variations of the P2RY12 and the residual clopidogrel on-treatment platelet reactivity after adjusting for the influence of CYP2C19 tested by thromboelastography (TEG).

METHODS

One hundred and eighty patients with acute coronary syndrome (ACS) treated with clopidogrel and aspirin were included and platelet function was assessed by TEG. Five selected P2RY12 single nucleotide polymorphisms (SNPs; rs6798347, rs6787801, rs6801273, rs6785930, and rs2046934), which cover the common variations in the P2RY12 gene and its regulatory regions, and three CYP2C19 SNPs (^*2,^*3,^*17) were genotyped and possible haplotypes were analyzed.

RESULTS

The high on-treatment platelet reactivity (HTPR) prevalence defined by a platelet inhibition rate <30% by TEG in adenosine diphosphate (ADP)-channel was 69 (38.33%). Six common haplotypes were inferred from four of the selected P2RY12 SNPs (denoted H₀ to H₅) according to the linkage disequilibrium R square (except for rs2046934). Haplotype H₁ showed a significantly lower incidence of HTPR than the reference haplotype (H₀) in the total study population while haplotypes H₁ and H₂ showed significantly lower incidences of HTPR than H₀ in the nonsmoker subgroup after adjusting for CYP2C19 effects and demographic characteristics. rs2046934 (T744C) did not show any significant association with HTPR.

CONCLUSIONS

The combination of common P2RY12 variations including regulatory regions rather than rs2046934 (T744C) that related to pharmacodynamics of clopidogrel in patients with ACS was independently associated with residual on-clopidogrel platelet reactivity. This is apart from the established association of the CYP2C19. This association seemed more important in the subgroup defined by smoking.

Genotyping, Platelet Activation, and Cardiovascular Outcome in Patients after Percutaneous Coronary Intervention: Two Pieces of the Puzzle of Clopidogrel Resistance

OBJECTIVES

Individual platelet responses to antiplatelet therapy depend on genetic, cellular, and clinical factors. CYP2C19 and P2Y12 receptor polymorphisms are implicated in platelet responses to antiplatelet treatment. We aimed to evaluate the impact of CYP2C19 and C34T P2Y12 genotyping on platelet reactivity and cardiovascular outcome in patients after percutaneous coronary intervention (PCI) on clopidogrel treatment.

METHODS

We enrolled 408 patients with stable coronary artery disease (CAD) receiving aspirin and clopidogrel (75 mg/day) 1 month after PCI. High on-treatment platelet reactivity was evaluated using the VerifyNow Assay in a subset of patients. CYP2C19*2 and C34T P2Y12 genotyping was performed by real-time polymerase chain reaction. The primary end point was the composite of death or hospitalization for cardiovascular causes, and patients were followed for a median time of 13 months.

RESULTS

In the total study population, 37% were carriers of at least 1 CYP2C19*2 loss-of-function allele, and 53% were carriers of at least 1 C34T loss-of-function allele. Interestingly, homozygotes of the CYP2C19*2 loss-of-function allele had significantly increased P2Y12 reaction units (PRU) (p = 0.007). However, PRU did not differ between carriers and noncarriers of the C34T loss-of-function allele (p = 0.41). Moreover, carriers of CYP2C19*2 had an increased hazard ratio (HR) for the occurrence of the primary end point (for carriers HR = 1.96, 95% CI 1.05-3.66, p = 0.03), whereas the C34T polymorphism had no impact on the cardiovascular outcome (p = 0.17). Finally, PRU was associated with cardiovascular outcome even after adjustment for the presence of any reduced function allele polymorphism.

CONCLUSIONS

We documented a different effect of CYP2C19 and P2Y12 receptor polymorphisms on platelet reactivity and cardiovascular outcome in CAD patients after PCI on clopidogrel treatment. Importantly, increased platelet reactivity adversely affects the cardiovascular outcome independently of the studied polymorphisms.

Ticagrelor overcomes high platelet reactivity in patients with acute myocardial infarction or coronary artery in-stent restenosis: a randomized controlled trial

High on-treatment platelet reactivity (HTPR) is accompanied by an increased risk of adverse outcomes. Direct comparison of the antiplatelet effects between ticagrelor and high-dose clopidogrel has not yet been reported in acute myocardial infarction (AMI) or coronary artery in-stent restenosis (ISR) patients with HTPR. Consecutive patients with AMI or coronary artery ISR treated with standard-dose clopidogrel (75 mg/day) were screened with the VerifyNow assay, defining HTPR as P2Y12 reaction units (PRUs) >208. Of the 102 screened patients, 48 (47.06%) patients with HTPR were randomly assigned to either ticagrelor (180 mg/90 mg twice daily) or high-dose clopidogrel (150 mg/day) for 24 hours. Baseline characteristics and mean PRUs were similar in both groups. After 24 hours, ticagrelor was associated with a significantly lower platelet reactivity than high-dose clopidogrel (44.38 ± 40.26  vs. 212.58 ± 52.34 PRU, P < 0.05). No patient receiving ticagrelor exhibited HTPR, whereas 15 (62.50%) patients after treatment with high-dose clopidogrel remained HTPR (P < 0.05). During the follow-up (mean, 138.42 ± 53.59 days), no patient exhibited a major bleeding event in either treatment group. In conclusion, in patients with AMI or coronary artery ISR exhibiting HTPR after standard clopidogrel treatment, ticagrelor is significantly more effective compared with high-dose clopidogrel in overcoming HTPR.

High platelet reactivity is associated with vascular function in patients after percutaneous coronary intervention receiving clopidogrel

BACKGROUND

In the present study, we evaluated the association of platelet reactivity with vascular function in patients after percutaneous coronary intervention receiving clopidogrel treatment.

METHODS

We enrolled 150 patients with stable CAD receiving clopidogrel regimen (75 mg/d), 1 month after percutaneous coronary intervention. Carotid-femoral pulse wave velocity (PWV) was measured as an index of aortic stiffness and augmentation index (AIx) as an index of arterial wave reflections. High on treatment platelet reactivity (HPR) was evaluated using VerifyNow Assay. VerifyNow reports its results in P2Y12 reaction units (PRU), and the diagnostic cutoff value is 230 PRU. Patients were evaluated prospectively up to 24 months. The primary end point was a composite of death from cardiovascular causes, nonfatal major cardiovascular events and hospitalization for cardiovascular causes.

RESULTS

There was no difference in the basic clinical and demographic characteristics between subjects with HPR and non-HPR. Subjects with high on treatment platelet reactivity and PRU>230 had significantly increased PWV (8.81 ± 2.25 m/s vs. 7.69 ± 1.95 m/s, p = 0.001) and AIx (25.27 ± 8.67% vs. 20.87 ± 10.57%, p = 0.04) compared to subjects with PRU≤230. PWV was also associated with PRU (r = 0.23, p = 0.02). HPR was associated with significantly increased risk of primary end point [HR = 5.38, 95%CI:(1.15, 26.04), p = 0.03].

CONCLUSIONS

Increased platelet reactivity is associated with impaired arterial stiffness in patients after percutaneous coronary intervention receiving clopidogrel treatment, highlighting another clinical factor implicated in individual platelet response to antiplatelet therapy. Moreover, increased platelet reactivity is associated with adverse outcome in these patients.

World heart federation expert consensus statement on antiplatelet therapy in east asian patients with ACS or undergoing PCI

Guideline recommendations on the use of dual antiplatelet therapy (DAPT) in patients with acute coronary syndromes and in those undergoing percutaneous coronary intervention (PCI) have been formulated by both the ACC/AHA and the ESC. These recommendations are based primarily on large, phase III, randomized, controlled trials of the P2Y12 inhibitors clopidogrel, prasugrel, and ticagrelor. However, few East Asian patients have been included in the trials to assess the use of these agents, particularly the newer agents prasugrel and ticagrelor. Additionally, an increasing body of data suggests that East Asian patients have differing risk profiles for both thrombophilia and bleeding compared with white patients, and that a different 'therapeutic window' of on-treatment platelet reactivity might be appropriate in East Asian patients. Furthermore, a phenomenon referred to as the 'East Asian paradox' has been described, in which East Asian patients have a similar or even a lower rate of ischaemic events after PCI compared with white patients, despite a higher level of platelet reactivity during DAPT. Recognizing these concerns, the World Heart Federation has undertaken this evidence-based review and produced this expert consensus statement to determine the antiplatelet treatment strategies that are most appropriate for East Asian patients.

Expert consensus document: World Heart Federation expert consensus statement on antiplatelet therapy in East Asian patients with ACS or undergoing PCI

Guideline recommendations on the use of dual antiplatelet therapy (DAPT) in patients with acute coronary syndromes and in those undergoing percutaneous coronary intervention (PCI) have been formulated by both the ACC/AHA and the ESC. These recommendations are based primarily on large, phase III, randomized, controlled trials of the P2Y12 inhibitors clopidogrel, prasugrel, and ticagrelor. However, few East Asian patients have been included in the trials to assess the use of these agents, particularly the newer agents prasugrel and ticagrelor. Additionally, an increasing body of data suggests that East Asian patients have differing risk profiles for both thrombophilia and bleeding compared with white patients, and that a different 'therapeutic window' of on-treatment platelet reactivity might be appropriate in East Asian patients. Furthermore, a phenomenon referred to as the 'East Asian paradox' has been described, in which East Asian patients have a similar or even a lower rate of ischaemic events after PCI compared with white patients, despite a higher level of platelet reactivity during DAPT. Recognizing these concerns, the World Heart Federation has undertaken this evidence-based review and produced this expert consensus statement to determine the antiplatelet treatment strategies that are most appropriate for East Asian patients.

Patients carrying CYP2C19 loss of function alleles have a reduced response to clopidogrel therapy and a greater risk of in-stent restenosis after endovascular treatment of lower extremity peripheral arterial disease

OBJECTIVE

This study evaluated the relationship between the cytochrome P450 (CYP) 2C19 genotype and the antiplatelet effect of clopidogrel therapy and investigated whether genotyping can predict the risk of ischemic events after endovascular treatment (ET) of lower extremity peripheral arterial disease.

METHODS

From January 2011 to July 2012, 120 consecutive patients with arteriosclerosis obliterans (TransAtlantic Inter-Society Consensus for the Management of Peripheral Arterial Disease [TASC II] A-C) in the superficial femoral artery were included in a prospectively maintained database. Patients received 75 mg clopidogrel and 100 mg aspirin daily for at least 5 days before TaqMan (Life Technologies, Grand Island, NY) of CYP2C19 single-nucleotide polymorphisms and thromboelastography of the clopidogrel response. ET was subsequently performed, and follow-up evaluations, including duplex ultrasound imaging and ankle-brachial index assessment, were performed at 1, 3, 6, and 12 months after ET. During the follow-up, stent patency was assessed by ultrasound imaging, computed tomography angiography, or digital subtraction angiography.

RESULTS

A total of 74 ET procedures were performed. Fifty of the enrolled patients (41.7%) completed the follow-up examinations and were included in the analysis. The mean duration of follow-up was 9.8 ± 2.1 months (range, 1-30 months). Carriers of at least one CYP2C19 loss-of-function (LOF) allele had a diminished pharmacodynamic response to clopidogrel (51.6 ± 20.1 vs. 39.8 ± 15.2 for patients without and with LOF alleles, respectively; P = .022). Carriers of one LOF allele had an increased incidence of ischemic events compared with patients without any LOF alleles (59.0% vs. 20.8%, respectively; P = .008). This trend was even more evident in patients with two LOF alleles compared with patients with no LOF alleles (100% vs. 20.8% ischemic events; P = .002). The cumulative primary patency rate at 12 months was 56.0%, with significant differences between groups (73.1% vs. 34.6% in patients without and with LOF alleles, respectively; P = .0.006). CYP2C19 LOF carrier status was associated with an increased rate of primary end points (P = .007). On the basis of their adenosine diphosphate-induced platelet aggregation, patients with high platelet reactivity had a significantly higher risk of ischemic events (P = .012). CYP2C19 genotypic classification (adjusted hazard ratio, 2.688; 95% confidence interval, 1.366-5.288; P = .004) and history of smoking (adjusted hazard ratio, 2.430; 95% confidence interval, 1.024-5.765; P = .044) were independent risk factors for ischemic events.

CONCLUSIONS

CYP2C19 LOF alleles were associated with a diminished platelet response to clopidogrel treatment. Patients carrying CYP2C19 LOF alleles who are treated with clopidogrel may trend toward a poor prognosis after ET.

Administration of a loading dose has no additive effect on platelet aggregation during the switch from ongoing clopidogrel treatment to ticagrelor in patients with acute coronary syndrome

BACKGROUND

Ticagrelor outperforms clopidogrel in preventing cardiovascular events in acute coronary syndrome. Despite the inclusion of a loading dose in the Platelet Inhibition and Patient Outcomes (PLATO) trial for all patients randomized to ticagrelor, it may not be necessary in patients receiving ongoing clopidogrel therapy. The aim of the present study was to assess whether a ticagrelor loading dose is associated with a further platelet inhibition during the switch from clopidogrel to ticagrelor in patients with acute coronary syndrome receiving ongoing antiplatelet treatment.

METHODS AND RESULTS

Fifty patients with acute coronary syndrome receiving aspirin and clopidogrel treatment were randomly assigned to a starting dose of ticagrelor (group 1, 90 mg; group 2, 180 mg). Platelet aggregation was measured using multiple electrode aggregometry and standard light transmission aggregometry just before the switch and at 2, 6, 24, and 72 hours. No relevant difference in platelet aggregation was observed between the 2 study arms at baseline (P=0.256). Residual platelet aggregation was significantly reduced in both arms 2 hours after the first administration of ticagrelor (P<0.001 for both), with no difference in aggregation between groups (multiple electrode aggregometry, 17.6±7.2 versus 18.1±6 U; P=0.281). Similar results were observed with LTA.

CONCLUSIONS

Switching from clopidogrel to ticagrelor without a reloading dose is feasible, and it does not hinder platelet aggregation inhibition in patients with acute coronary syndrome. Further prospective studies are needed to assess the clinical relevance of our findings.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01795820.

Antiplatelet therapy in patients undergoing percutaneous coronary intervention: economic considerations

Percutaneous coronary intervention (PCI) is one of the most common medical procedures performed for treatment of coronary artery disease. Antiplatelet medications as adjunctive therapy for PCI are used routinely, with indications for specific agents or their combinations varying depending on the clinical scenario. While the cost-effectiveness of well-established agents has been extensively studied, newer drugs have not been evaluated as thoroughly. In addition, the clinical application of some antiplatelet drugs has recently changed, thus making older studies of cost effectiveness less applicable to the current landscape of clinical practice. This article reviews cost-effectiveness considerations of antiplatelet therapies in the treatment of coronary artery disease in patients undergoing PCI. Aspirin, P2Y12 inhibitors including clopidogrel and the newer agents prasugrel and ticagrelor, as well as glycoprotein (GP) IIb/IIIa inhibitors, are discussed. Overall, the use of dual antiplatelet therapy with aspirin and a P2Y12 inhibitor in patients undergoing PCI improves ischaemic outcomes and appears to be cost effective. The few available studies suggest that the recently approved medications prasugrel and ticagrelor are cost-effective alternatives to clopidogrel. However, no direct comparison between these two newer agents is available. The indications for GP IIb/IIIa inhibitors have changed in the current PCI era, and there is a paucity of cost-effectiveness data for their use in contemporary care.

Cost-effectiveness of prasugrel in a US managed care population

OBJECTIVE

Decision-makers in the US may be interested in the applicability to their populations of cost-effectiveness results generated from clinical trial populations.

METHODS

An economic model estimating the cost-effectiveness of prasugrel plus aspirin relative to clopidogrel plus aspirin for patients with acute coronary syndromes (ACS) undergoing percutaneous coronary intervention (PCI) was developed from a managed care organization (MCO) perspective. The model estimated 15-month cardiovascular events or bleeding-related outcomes, life expectancy, and costs for patients who received thienopyridine treatment during and after a PCI following a diagnosis of ACS. Post-ACS event rates for patients treated with clopidogrel were from an MCO. The relative risks of these events with prasugrel compared with clopidogrel were from a head-to-head clinical trial.

RESULTS

The results of the base-case analysis indicated that, in an MCO population, use of prasugrel-based therapy rather than clopidogrel-based therapy at current prices resulted in cost-savings and fewer clinical events over the 15 months after an ACS diagnosis followed by PCI. At possible lower prices for generic clopidogrel-based therapy, the cost-effectiveness ratio for prasugrel-based therapy compared with clopidogrel-based therapy was between $6643 and $13,906 per life-year gained. The results were most sensitive to the relative costs of the two treatments and the cost for hospital stays.

LIMITATIONS

Limitations of the study included lack of follow-up of patients disenrolling from the MCO before the end of the 15-month observation period, the assumption of equal relative risks of events in an MCO as in the clinical trial, and the lack of information on the ratio of cost to charges in the MCO database.

CONCLUSIONS

Use of prasugrel-based therapy compared with clopidogrel-based therapy in ACS patients having a PCI resulted in cost-savings at current prices and favorable cost-effective ratios at likely generic prices for clopidogrel-based therapy because of offsetting savings in the costs of rehospitalization.

Secondary Stroke Prevention in Women

In a meta-analysis of results from 21 randomized trials comparing antiplatelet therapy with placebo in 18,270 patients with prior stroke or transient ischemic attack, antiplatelet therapy was associated with a 28% relative odds reduction in nonfatal strokes and a 16% reduction in fatal strokes, while another trial for secondary prevention with atorvastastin 80 mg showed a 16% risk reduction in time to first occurrence of stroke (adjusted hazard ratio: 0·84, 95% CI: 0·71–0·99). However, few studies have examined the sex differences regarding the efficacy of these treatments. Specifically, recent studies have reported higher rates of perioperative complications during endarterectomy in women. Nonetheless, to date, the data on the effects of carotid artery stenting in women, coming from diverse studies and meta-analyses, have been limited owing to the small number of female patients examined. Owing to this, the evidence of the benefit for women is unclear. Peculiar pathophysiological aspects of stroke, the higher stroke risk in some specific periods in life (e.g., pregnancy, puerperium and older age) and worse documented stroke outcome in women suggest that sex does matter in stroke management. Thus, future randomized controlled trials need to be sex-balanced, in order to better understand the efficacy of appropriate secondary stroke prevention therapy in women.

Oral antiplatelet therapy in stroke prevention. Minireview

BACKGROUND

Antiplatelet therapy plays a crucial role in the primary and secondary prevention of noncardioembolic ischemic stroke / transient ischemic attacks (IS/TIA). Several antiplatelet agents are available. This review deals with the characteristics of particular antiplatelet agents as well as choice of antiplatelet treatment in various situations, based on the evidence and international recommendations.

METHODS

PubMed and Stroke Trials Registry on-line databases and the European Stroke Organisation Guidelines for Management of IS/TIA 2008 and update of the recommendations of the American Heart Association / American Stroke Association Council 2008 on Stroke were used.

RESULTS

Acetylsalicylic acid (ASA) is the only antiplatelet drug used in primary prevention, mainly to reduce the risk of myocardial infarction (MI), but also in women aged 45 years or more and in some patients with non-valvular atrial fibrillation to reduce risk of IS/TIA. In the secondary prevention of noncardioembolic IS/TIA, ASA in combination with long release dipyridamole (DIP) and clopidogrel (CLOP) alone are considered first choice therapies. The choice of the particular antiplatelet agent should be individualized according to the patient risk factor profiles and treatment tolerance. ASA alone or triflusal can be used alternatively in patients who cannot be treated with either ASA+DIP or CLOP. The use of indobufen should be considered only in patients in need of temporary interruption of the antiplatelet therapy. Ticlopidine (TIC) should not be newly introduced into the treatment. Currently, insufficient data are available on the use of cilostazol in IS/TIA prevention.

Revaluation of clopidogrel: let the data speak for themselves

Clopidogrel was believed to be superior to aspirin by the well-known CAPRIE trial. However, no other large clinical trials demonstrated the same results, but all focused on the combination use of clopidogrel with aspirin, and combination therapy in CREDO was called the "Emperor's New Clothes". However, no one overturned the results of these clinical trials by quantitatively analyzing them. We reviewed ten large-scale clinical trials about clopidogrel. On the basis of results of CAPRIE, CREDO and CHARISMA trials, we re-estimated their minimal sample sizes and their powers by three well-established statistical methodologies. From the results of CAPRIE, we inferred that the minimal sample size should be 85 086 or 84 968 but its power was only 30.70%. A huge gap existed. The same was also true of CREDO and CHARISMA trials. Moreover, in CAPRIE trial, 0 was included in the 95% confidence interval and 1 was included in the 95% confidence interval for the relative risk. There were some paradoxical data in CAPRIE trial. We are led to conclude that the results in CAPRIE, CREDO, and from the subgroup analysis in CHARISMA trials were questionable. These results failed to demonstrate that clopidogrel was superior to aspirin or that clopidogrel used in combination with aspirin was better than aspirin alone. The cost-effectiveness analyses by some previous studies were not reliable.

Thrombin receptor (PAR-1) antagonists as novel antithrombotic agents

In addition to its central role in haemostasis and wound healing, thrombin activates platelets and smooth muscle cells by proteolytic activation of cell surface protease-activated receptor-1 (PAR-1), which is also known as the thrombin receptor. Thrombin is the most potent activator of human platelets and, as such, a thrombin receptor antagonist is likely to exert potent antithrombotic effect in platelet-rich arterial thrombosis. As thrombin receptor antagonism does not inhibit the ability of thrombin to generate fibrin, such an agent is likely to have less bleeding liability than conventional anticoagulants. The proof-of-concept of the antithrombotic effect of PAR-1 antagonists has been established in several non-human primate models. The current success of PAR-1 research is underscored by the advancement of two candidates into clinical trails for acute coronary syndrome by Schering-Plough and Eisai Company.

[STEMI guidelines 2008--Do they influence today's myocardial infarction treatment strategies in rural areas?]

2008 new guidelines for the management of patients with ST-elevation myocardial infarction were published by the European Society of Cardiology. For daily clinical practice, changes in recommendations concerning the preferred revascularization therapy according to different time delays are of great interest. This review focuses on possible implications of these new guidelines on the choice of reperfusion strategies in rural areas.

Cost effectiveness of rosuvastatin in patients at risk of cardiovascular disease based on findings from the JUPITER trial

OBJECTIVE

This study assessed the long-term cost effectiveness of rosuvastatin therapy compared with placebo in reducing the incidence of major cardiovascular (CVD) events and mortality.

METHODS

A probabilistic Monte Carlo simulation model estimated long-term cost effectiveness of rosuvastatin therapy (20 mg daily) for the prevention of CVD mortality and morbidity. The model included three stages: (1) CVD prevention simulating the 4 years of the JUPITER trial, (2) initial CVD prevention beyond the trial, and (3) subsequent CVD event prevention. A US payer perspective was assessed reflecting direct medical costs, and up to a lifetime horizon. Sensitivity analyses tested the robustness of the model estimates.

RESULTS

For a hypothetical cohort of 100,000 patients at moderate and high risk of CVD events based on Framingham risk of ≥10%, estimated quality-adjusted life-years (QALYs) gained with rosuvastatin therapy compared with placebo was 33,480 over a lifetime horizon, and 25,380 and 9916 over 20-year and 10-year horizons, respectively. Approximately 12,073 events were avoided over the lifetime; 6,146 non-fatal MIs, 2905 non-fatal strokes, and 4030 CVD deaths avoided. Estimated incremental cost-effectiveness ratio (ICER) for cost per QALY was $7062 (lifetime), $10,743 (20-year horizon), and $44,466 (10-year horizon). For a hypothetical cohort similar to the overall JUPITER population, the cost per QALY ICER was $11,025 for the lifetime and $60,112 for a 10-year horizon.

LIMITATIONS

The cost-effectiveness comparison of rosuvastatin 20 mg was against no active treatment (as opposed to an alternative statin) due to lack of comparative cardiovascular morbidity and mortality risk reduction data for other statins in a population similar to the JUPITER trial population. The analysis was conducted from the payer perspective and lack of inclusion of indirect costs limit interpretability of results from a societal perspective.

CONCLUSIONS

Treatment with rosuvastatin 20 mg daily, is a cost-effective treatment alternative to no treatment in patients at a higher risk (Framingham risk≥10%) of CVD.

Cost effectiveness of enoxaparin in acute ST-segment elevation myocardial infarction: the ExTRACT-TIMI 25 (Enoxaparin and Thrombolysis Reperfusion for Acute Myocardial Infarction Treatment-Thrombolysis In Myocardial Infarction 25) study

OBJECTIVES

We used a U.S. model of health care costs to examine the cost effectiveness of enoxaparin compared with unfractionated heparin (UFH) as adjunctive therapy for fibrinolysis in patients with ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

The ExTRACT-TIMI 25 (Enoxaparin and Thrombolysis Reperfusion for Acute Myocardial Infarction Treatment-Thrombolysis In Myocardial Infarction 25) study, a large, randomized, multinational trial, demonstrated a reduction in death or nonfatal myocardial infarction when enoxaparin was used instead of UFH as adjunctive therapy for fibrinolysis in patients with STEMI.

METHODS

We used patient-level clinical outcomes and resource use from the ExTRACT-TIMI 25 trial and estimates of life expectancy gains as a result of the prevention of the clinical events on the basis of the Framingham Heart Study.

RESULTS

Index hospitalization costs trended lower by $126 in the enoxaparin group (95% confidence interval [CI]: -$295 to $49). Thirty-day costs trended higher by $102 for enoxaparin (95% CI: $108 to $314). Patients receiving enoxaparin gained an average of 0.12 life-years relative to patients given UFH. Estimated total lifetime costs were $1,207 higher in the enoxaparin group (95% CI: $491 to $1,923). The incremental cost-effectiveness ratio of enoxaparin compared with UFH was $5,700 per life-year gained, with 99.9% of bootstrap-derived estimates <$50,000 per life-year gained. Using a probabilistic sensitivity analysis, there is a 90% probability that enoxaparin is cost effective for lifetime, provided that the willingness-to-pay value exceeds $50,000.

CONCLUSIONS

Based on a U.S. model of health care economics, the strategy of using enoxaparin instead of UFH as adjunctive therapy for fibrinolysis in patients with STEMI is cost effective according to commonly used benchmarks.

Cost-effectiveness of clopidogrel plus aspirin versus aspirin alone for secondary prevention of cardiovascular events: results from the CHARISMA trial

OBJECTIVE

To determine the incremental cost-effectiveness of clopidogrel plus aspirin (C + A) compared with aspirin (A) alone during the Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management and Avoidance (CHARISMA) trial from a US payer perspective.

BACKGROUND

Although the CHARISMA trial did not find a benefit of adding clopidogrel to aspirin in its overall study cohort, a benefit was suggested in a prespecified subgroup of patients with established cardiovascular (CV) disease. The cost-effectiveness of dual antiplatelet therapy in this population is unknown.

METHODS

Medical resource utilization was assessed prospectively, and costs for hospitalizations, physician services, outpatient care, and medications were assigned using 2007 US dollars. Life expectancy was estimated contingent on fatal and nonfatal CV events using statistical models of long-term survival from the Saskatchewan Health database.

RESULTS

C + A was associated with a 12.5% relative reduction in CV death, myocardial infarction, or stroke compared with A alone (6.9% vs. 7.9%, P = 0.048) over a median 28 months of follow-up. Severe or moderate bleeding events were higher in patients receiving C + A versus A alone (3.6% vs. 2.5%, P < 0.001). Mean cost/patient was $2607 higher for C + A, while projected life expectancy increased by an average of 0.072 years due to fewer in-trial events. The resulting incremental cost-effectiveness ratio (ICER) for C + A was $36,343/year of life gained. Findings were insensitive to discount rate, life expectancy projections, post-event costs, and indirect costs from lost productivity; the ICER was most sensitive to the cost of clopidogrel. Bootstrap analysis demonstrated that the ICER for C + A remained <$50,000/life-year gained in 70.6% of bootstrap replicates and <$100,000/life-year gained in 87.4%.

CONCLUSIONS

Among patients with established CV disease, adding clopidogrel to aspirin appears to increase life expectancy modestly at a cost generally considered acceptable within the US health-care system.

Dinucleoside polyphosphates: strong endogenous agonists of the purinergic system

The purinergic system is composed of mononucleosides, mononucleoside polyphosphates and dinucleoside polyphosphates as agonists, as well as the respective purinergic receptors. Interest in the role of the purinergic system in cardiovascular physiology and pathophysiology is on the rise. This review focuses on the overall impact of dinucleoside polyphosphates in the purinergic system. Platelets, adrenal glands, endothelial cells, cardiomyocytes and tubular cells release dinucleoside polyphosphates. Plasma concentrations of dinucleoside polyphosphates are sufficient to cause direct vasoregulatory effects and to induce proliferative effects on vascular smooth muscle cells and mesangial cells. In addition, increased plasma concentrations of a dinucleoside polyphosphate were recently demonstrated in juvenile hypertensive patients. In conclusion, the current literature accentuates the strong physiological and pathophysiological impact of dinucleoside polyphosphates on the cardiovascular system.

Adherence to guidelines for sensitivity analysis: cost-effectiveness analyses of dual oral antiplatelet therapy

OBJECTIVE

Cost-effectiveness analyses of new treatments for cardiovascular disease frequently require input parameters whose values are known with uncertainty due to limited data. The objective of this paper is to examine the extent to which published sensitivity analyses addressing this uncertainty adhere to Health Technology Assessment (HTA) guidelines.

RESEARCH DESIGN AND METHODS

A systematic review of published cost-effectiveness analyses was performed for an example drug treatment scenario, dual oral antiplatelet therapy compared with aspirin alone following acute coronary syndromes and/or percutaneous coronary intervention. The following medical literature databases were searched for articles published from January 1997 to June 2007: PubMed, Cochrane Collaboration, EMBASE and the Health Economic Evaluation Database (HEED). Evidence tables were created to show the sensitivity of the cost-effectiveness estimates to changes in the input parameter values, as well as the data sources used for the reference-case and sensitivity analysis input parameter values. The extent to which the sensitivity analyses adhered to HTA guidelines were also examined.

RESULTS

Cost-effectiveness ratios were most sensitive to changes in the efficacy of dual antiplatelet therapy and reference-case model assumptions about costs beyond the trial period. Although alternative values tested in the sensitivity analysis for some input parameters were based on observed ranges or distributions, alternative values tested for many other input parameters were assumed without justification.

CONCLUSIONS

Sensitivity analyses in the cost-effectiveness studies of dual oral antiplatelet therapy were not fully adherent with HTA guidelines. In particular, long-term costs and benefits were not always included in the sensitivity estimates, the impact of differential effects on death and myocardial infarction was not explored, and justification for the alternative parameter values tested was not always provided.

Fondaparinux versus Enoxaparin in non-ST-elevation acute coronary syndromes: short-term cost and long-term cost-effectiveness using data from the Fifth Organization to Assess Strategies in Acute Ischemic Syndromes Investigators (OASIS-5) trial

BACKGROUND

The study aimed to compare the short-term costs and long-term cost-effectiveness of 2 antithrombotics, fondaparinux and enoxaparin, for non-ST-elevation acute coronary syndrome in the United States.

METHODS

It was based on a large randomized trial of 20,078 patients Fifth Organization to Assess Strategies in Acute Ischemic Syndromes Investigators [OASIS-5] comparing the therapies in these patients. In OASIS-5, fondaparinux patients had about half the rate of major bleeding 9 days after randomization and at least as good clinical outcomes (death, myocardial infarction, major bleeding and stroke) after 6 months of follow-up. Health care resource use and clinical efficacy data from the trial were incorporated into a cost-effectiveness model as applied to a general US health care system both for the time horizon of the study (6 months) and over the longer term.

RESULTS

The 180-day cost analysis indicates that fondaparinux would generate a cost saving of $547 per patient (95% CI $207-$924). Sensitivity analysis suggested that savings could vary between $494 and $733. When 180-day cost and clinical results were extrapolated to long-term cost-effectiveness, fondaparinux was dominant (less costly and more effective in terms of quality-adjusted life-years) under most scenarios.

CONCLUSIONS

Fondaparinux is a more cost-effective antithrombotic agent than enoxaparin in non-ST-elevation acute coronary syndrome. This is true across the range of event risks seen in OASIS-5.

Use of Aspirin Versus Clopidogrel Plus Aspirin After Coronary Artery Bypass Graft Surgery

Aspirin and clopidogrel together reduce the risk of recurrent thrombosis-related events in patients with acute coronary syndromes or stent revascularization and may reduce thrombosis-induced saphenous vein graft failure. In this retrospective, observational study, 4297 patients were assigned to 2 groups after coronary artery bypass graft surgery, based on medications prescribed at hospital discharge: aspirin only (n = 3318) or aspirin plus clopidogrel (n = 979). At 4-year follow-up, unadjusted survival was similar between the 2 groups (aspirin—clopidogrel, 87.9% vs aspirin-only, 88.8%, P = .43). After statistical adjustment using Cox regression analysis, dual anti-platelet therapy at hospital discharge was not associated with improved survival (odds ratio 1.055, 95% confidence interval 0.7-1.4, P = .72). In propensity score-based, case-matched populations (962 patients each), similar results were obtained (odds ratio 0.996, 95% confidence interval 0.7-1.4, P = .98). In our study population, aspirin plus clopidogrel did not provide survival benefit over treatment with aspirin alone in 4 years after coronary artery bypass graft surgery.

Prevalence, clinical profile, and cardiovascular outcomes of atrial fibrillation patients with atherothrombosis

BACKGROUND

Atrial fibrillation (AF) is a major risk factor (RF) for ischemic stroke. Its prevalence and prognostic impact in patients with atherothrombosis are unclear.

METHODS

Risk factors, drug usage, and 1-year cardiovascular (CV) outcomes (CV death, myocardial infarction [MI], and stroke) were compared in AF and non-AF patients from the REduction of Atherothrombosis for Continued Health (REACH) Registry, an international, prospective cohort of 68,236 stable outpatients with established atherothrombosis or>or=3 atherothrombotic RFs.

RESULTS

Atrial fibrillation and 1-year follow-up data are available for 63,589 patients. The prevalence of AF was, 12.5%, 13.7%, 11.5%, and 6.2% among coronary artery disease, CV disease, peripheral artery disease, and RF-only patients, respectively. Of the 6,814 patients with AF, 6.7% experienced CV death, nonfatal MI, or nonfatal stroke within a year. The annual incidence of nonfatal stroke (2.4% vs 1.6%, P<.0001) and unstable angina (6.0% vs 4.0%, P<.00001) was higher, and CV death was more than double (3.2% vs 1.4%, P<.0001), in AF versus non-AF patients. In these patients with or at high risk of atherothrombosis, most patients with AF received antiplatelet agents, but only 53.1% were treated with oral anticoagulants. Even with high CHADS2 (congestive heart failure, hypertension, aging, diabetes mellitus, and stroke) scores, anticoagulant use did not exceed (59%). The rate of bleeding requiring hospitalization was higher in AF versus non-AF patients (1.5% vs 0.8%, P<.0001), possibly related to the more frequent use of anticoagulants (53.1% vs 7.1%).

CONCLUSIONS

Atrial fibrillation is common in patients with atherothrombosis, associated with more frequent fatal and nonfatal CV outcomes, and underuse of oral anticoagulants.

Pharmacoeconomic concepts in antiplatelet therapy: understanding cost-effectiveness analyses using clopidogrel as an example

The rising cost of drug therapy has been accompanied by demands from payers for pharmacoeconomic studies to assess the value for money of new treatments. There are 5 types of such analyses: cost analysis (evaluates only costs); cost minimization (compares costs of treatments with identical outcomes); cost-effectiveness (evaluates the cost of treatment in relation to clinical benefit to derive a cost per outcome); cost utility (evaluates cost of treatment in relation to survival adjusted for quality of life,) and cost benefit (evaluates all clinical outcomes, such as prolonged life, in monetary terms). The most commonly used are cost-effectiveness and cost utility. The aim of this article is to provide the nonexpert reader with a basic understanding of these analyses, using pharmacoeconomic evaluations of clopidogrel for acute coronary syndromes as examples. Greater clinician understanding of pharmacoeconomic principles (and pitfalls) will enhance input of the physicians into the decision-making process to maximize the benefit of limited health care resources.

The primary and secondary prevention of coronary artery disease: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

The following chapter devoted to antithrombotic therapy for chronic coronary artery disease (CAD) is part of the Antithrombotic and Thrombolytic Therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Grade 1 recommendations are strong and indicate that the benefits do or do not outweigh risks, burden, and costs. Grade 2 suggests that individual patient values may lead to different choices (for a full understanding of the grading see the "Grades of Recommendation" chapter by Guyatt et al in this supplement, CHEST 2008; 133[suppl]:123S-131S). Among the key recommendations in this chapter are the following: for patients with non-ST-segment elevation (NSTE)-acute coronary syndrome (ACS) we recommend daily oral aspirin (75-100 mg) [Grade 1A]. For patients with an aspirin allergy, we recommend clopidogrel, 75 mg/d (Grade 1A). For patients who have received clopidogrel and are scheduled for coronary bypass surgery, we suggest discontinuing clopidogrel for 5 days prior to the scheduled surgery (Grade 2A). For patients after myocardial infarction, after ACS, and those with stable CAD and patients after percutaneous coronary intervention (PCI), we recommend daily aspirin (75-100 mg) as indefinite therapy (Grade 1A). We recommend clopidogrel in combination with aspirin for patients experiencing ST-segment elevation (STE) and NSTE-ACS (Grade 1A). For patients with contraindications to aspirin, we recommend clopidogrel as monotherapy (Grade 1A). For long-term treatment after PCI in patients who receive antithrombotic agents such as clopidogrel or warfarin, we recommend aspirin (75 to 100 mg/d) [Grade 1B]. For patients who undergo bare metal stent placement, we recommend the combination of aspirin and clopidogrel for at least 4 weeks (Grade 1A). We recommend that patients receiving drug-eluting stents (DES) receive aspirin (325 mg/d for 3 months followed by 75-100 mg/d) and clopidogrel 75 mg/d for a minimum of 12 months (Grade 2B). For primary prevention in patients with moderate risk for a coronary event, we recommend aspirin, 75-100 mg/d, over either no antithrombotic therapy or vitamin K antagonist (Grade 1A).

Cost-effectiveness of clopidogrel: seeing through the smoke

BACKGROUND

The authors reviewed various recommendations and practices for cost-effectiveness analysis. They also performed a PubMed search for clopidogrel and cost-effectiveness from 2004 to early 2008 to obtain original analyses published in English to look for possible associations of assumptions and conclusions with reported pharmaceutical support.

RESULTS

. Inclusion of incident cases and truncation at a sensible follow-up time more appropriately reflect the burden to be assumed by third-party payers. Extending the time horizon too far runs the risk of decreasing any relation with future reality. Parsimony cannot justify simplifications that omit relevant issues such as noncoronary costs, which worsen the calculated cost-effectiveness ratio of clopidogrel by 5% to 27%. The choice of the population to be analyzed has a major effect on cost-effectiveness: pharmaceutically sponsored studies published between 2004 and early 2008 focused on high-risk patients and have routinely shown more favorable cost-effectiveness ratios for clopidogrel than studies without pharmaceutical support.

CONCLUSION

. Any entity hoping to make the cost-effectiveness ratio of clopidogrel look more favorable would prefer the isolated, cohort approach and limit the analysis to high-risk patients most likely to benefit from it. This approach ignores the reality of medical policies and does not address the most relevant questions regarding the optimum use of clopidogrel.

Cost comparison of four revascularisation procedures for the treatment of multivessel coronary artery disease

OBJECTIVE

An economic evaluation was performed, using modelling techniques, to compare 1-year total costs of four revascularisation procedures in patients with multivessel disease: on-pump coronary artery bypass grafting (CABG); off-pump CABG; percutaneous coronary intervention (PCI) with bare-metal stents (BMS); and PCI with drug-eluting stents (DES).

METHODS

Clinical data were derived from four randomised clinical trials comparing CABG versus PCI, as well as from literature reviews. Resource use and unit cost estimates were modelled to reflect current Canadian practice.

RESULTS

This study demonstrated that 1 year after the initial revascularisation, PCI with BMS is the least costly procedure, followed by off-pump CABG, PCI with DES and on-pump CABG. DES became the most costly procedure if 3.5 or more DES were used or if staged PCI was performed.

Vasodilator-stimulated phosphoprotein phosphorylation analysis prior to percutaneous coronary intervention for exclusion of postprocedural major adverse cardiovascular events

BACKGROUND

Despite dual antiplatelet therapy, the rate of major adverse cardiovascular events (MACE) after percutaneous coronary angioplasty remains high. Studies have shown interindividual variations in response to clopidogrel. Furthermore, there is an apparent link between clinical outcomes and clopidogrel resistance.

OBJECTIVES

To investigate the value of platelet reactivity index (PRI), assessed by vasodilator-stimulated phosphoprotein (VASP) phosphorylation analysis, for predicting MACE after percutaneous coronary intervention (PCI) with stent implantation.

METHODS

A prospective monocentric study was performed on 144 patients undergoing PCI. PR was evaluated by VASP phosphorylation analysis 24 h after they received a 300-mg loading dose of clopidogrel. MACE were recorded during a 6-month follow-up. Patients were divided into quintiles according to PRI, as assessed by VASP analysis. The receiver operating characteristic (ROC) curve served to determine the optimal cut-off value of VASP analysis to detect MACE.

RESULTS

Of the 144 patients, 34% had stable angina pectoris, 40% silent ischemia, and 26% low-risk non-ST-segment elevation acute coronary syndrome. During the follow-up, 21 MACE were observed. Patients in quintile 1 of VASP analysis had a significantly lower risk of MACE as compared with those among the four higher quintiles (0 vs. 21, P < 0.01). ROC curve analysis of VASP showed an optimal cut-off value of 50% PR to exclude MACE. The negative predictive value of the test was 100%.

CONCLUSIONS

VASP phosphorylation analysis can evaluate the individual response to clopidogrel loading dose prior to PCI and predict postprocedural MACE.