Can we afford to eliminate restenosis?

Treatment of bioresorbable scaffold failure

Bioresorbable scaffolds (BRS) are a promising new interventional treatment strategy for coronary artery disease (CAD). They are intended to overcome some of the shortcomings of metal drug-eluting stents (DES), mainly late reinterventions which occur at a consistent rate after one year and have not been reduced by the use of local drug elution. Initial experience in non-complex lesions established efficacy in opening the vessel and the concept of bioresorption. However, with the use of BRS in more complex lesions, the incidence of BRS failure, including both scaffold restenosis and thrombosis, has also increased. Therefore, understanding of both the pathophysiology and of the available treatment options of scaffold failure remains an important issue in ensuring procedural and long-term clinical success.

Drug-eluting stents: from evidence to policy

Drug-eluting stents are a major breakthrough in cardiology, with the Cypher (Cordis Corporation) and Taxus (Boston Scientific) stents preventing 60-70% of repeat coronary revascularizations, compared with bare metal stents. Both evidence- and risk-based application of drug-eluting stents is expected to create relevant financial and equity problems to most public hospitals, as the cost of drug-eluting stents is over 1000 higher than traditional stents. In the perspective of third-party payers, drug-eluting stents are cost-effective revascularization strategies for a large portion of patients actually undergoing stenting. However, adequate guidelines and reimbursement strategies are still awaited in several countries.

Magnolol attenuates neointima formation by inducing cell cycle arrest via inhibition of ERK1/2 and NF-kappaB activation in vascular smooth muscle cells

BACKGROUND

Endovascular injury induces switching of contractile phenotype of vascular smooth muscle cells (VSMCs) to synthetic phenotype, thereby causing proliferation of VSMCs leading to intimal thickening. The purpose of this study was to assess the effect of magnolol on the proliferation of VSMCs in vitro and neointima formation in vivo, as well as the related cell signaling mechanisms.

METHODS

Tumor necrosis factor alpha (TNF-alpha) induced proliferation ofVSMCs was assessed using colorimetric assay. Cell cycle progression and mRNA expression of cell cycle associated molecules were determined by flow cytometry and reverse transcription polymerase chain reaction (RT-PCR) respectively. The signaling molecules such as ERK1/2,JNK, P38 and NF-kappaB were determined by Western blot analysis. In addition, rat carotid artery balloon injury model was performed to assess the effect of magnolol on neointima formation in vivo.

RESULTS

Oral administration of magnolol significantly inhibited intimal area and intimal/medial ratio (I/M). Our in vitro assays revealed magnolol dose dependently induced cell cycle arrest at G0/G1. Also, magnolol inhibited mRNA and protein expression of cyclin D1, cyclin E, CDK4 and CDK2 in vitro and in vivo. The cell cycle arrest was associated with inhibition of ERK1/2 phosphorylation and NF-kappaB translocation.

CONCLUSION

Magnolol suppressed proliferation of VSMCs in vitro and attenuated neointima formation in vivo by inducing cell cycle arrest at G0/G1 through modulation of cyclin D1, cyclin E, CDK4 and CDK2 expression.

GENERAL SIGNIFICANCE

Thus, the results suggest that magnolol could be a potential therapeutic candidate for the prevention of restenosis and atherosclerosis.

Economic evaluation of strategies to reduce sudden cardiac death in young athletes

OBJECTIVE

There is controversy about appropriate methods to reduce sudden cardiac death (SCD) in young athletes, but there is limited evidence on costs or consequences of alternative strategies. The objective of this study was to evaluate the cost-effectiveness of adding electrocardiogram (ECG) screening to the currently standard practice of preparticipation history and physical examination (H&P) to reduce SCD.

METHODS

Decision analysis modeling by using a societal perspective, with annual Markov cycles from age 14 until death. Three screening strategies were evaluated: (1) H&P, with cardiology referral if abnormal (current standard practice); (2) H&P, plus ECG after negative H&P, and cardiology referral if either is abnormal; and (3) ECG only, with cardiology referral if abnormal. Children identified with SCD-associated cardiac abnormalities were restricted from sports and received cardiac treatment. Main outcome measures were costs of screening and treatment, quality-adjusted life years (QALYs), and premature deaths averted.

RESULTS

Relative to strategy 1, incremental cost-effectiveness is $68800/QALY for strategy 2 and $37700/QALY for strategy 3. Monte Carlo simulation revealed the chance of incremental cost-effectiveness compared with strategy 1 was 30% for strategy 2 and 66% for strategy 3 (assumed willingness to pay ≤$50000/QALY). Compared with strategy 1, strategy 2 averted 131 additional SCDs at $900000 per case, and strategy 3 averted 127 SCDs at $600000 per case.

CONCLUSIONS

Under a societal willingness to pay threshold of $50000/QALY, adding ECGs to current preparticipation evaluations for athletes is not cost-effective, with costs driven largely by false-positive findings.

Acute myocardial infarction late following stent implantation: Incidence, mechanisms and clinical presentation

Acute myocardial infarction (AMI) can occur late following stent implantation with an incidence up to >6% at 3-4 years, with no difference between DES and BMS. AMI can originate either from the stented site or from disease progression at nonstented sites. Restenosis, against previous thoughts, can lead to AMI. Stent thrombosis occurs with similar overall frequency following DES and BMS implantations, although a higher very late stent thrombosis with DES has been observed. Dissimilar mechanisms between BMS and DES thrombosis are very likely, with impaired neointimal healing being the rule for DES but the exemption for BMS. The use of invasive imaging techniques is useful in elucidating the involved mechanism. Disease progression is a particularly important cause of AMI late post stenting. The angiographic study depicted stent failure and disease progression equally implicated in the AMI late post stenting. When the AMI underlying mechanism is stent thrombosis, it usually occurs earlier and more frequently presented as STEMI compared to the other causes of AMI. The AMI caused by restenosis is more often presented as nonSTEMI, while disease progression leads to AMI later than the other causes. Further research should address equally not only the stent related inadequacies but also disease progression as causes of the future AMI. Angiographic follow-up and intracoronary imaging seem the most appropriate methods to define the exact pathophysiologic mechanism responsible for the AMI post stenting.

Cost analysis of four major drug-eluting stents in diabetic populations

AIM

To use an indirect comparisons approach and conduct a cost analysis comparing four drug-eluting stents (DES) from a United States (US) payer (i.e., fixed-fee reimbursement) perspective.

METHODS AND RESULTS

Studies were chosen that randomised two or more DES in diabetic patients. A one-year target lesion revascularisation (TLR) risk for Taxus was first derived. Risk Ratios (RRs) for each DES versus Taxus were calculated through meta-analyses. The RRs were multiplied by the average TLR risk for Taxus to estimate DES TLR risks. Estimates were added to a budget-impact model, along with utilisation and reimbursement rates for diagnosis-related groups. Budgets were calculated, assuming 100% stent use and 200,000 diabetic beneficiaries. One-year TLR risks were estimated to be 3.2%, 7.1%, 6.9% and 7.9% for Cypher, Endeavor, Taxus and Xience respectively. By substituting Cypher for DES with higher TLR, results predicted annual cost-savings greater than $146 million per population ($ 733 per patient). Results were comparable when assuming no difference in TLR risk between Endeavor, Taxus and Xience.

CONCLUSIONS

When outcomes from trials of diabetic populations are analysed and used in a budget-impact model from a US payer perspective, the use of Cypher is associated with lower TLR rates, which translates into large potential cost savings.

Cost-effectiveness of drug-eluting stents versus bare metal stents in clinical practice

BACKGROUND

Drug-eluting stents (DES) reduce the need for repeat target revascularization (TVR) compared with bare metal stents (BMS) but are more costly. The objective was to evaluate the cost-effectiveness of DES versus BMS.

METHODS AND RESULTS

We evaluated clinical outcomes and costs of care over 3 years in 1147 undergoing BMS before the availability of DES and 1247 DES patients at Wake Forest University Baptist Medical Center from 2002 to 2005. Costs for index stenting, TVR, and clopidogrel use were assessed. The 2 groups were well matched for baseline characteristics. Index stenting costs were $1846 higher per patient for DES versus BMS ($1737 more to $1950 more). At 3 years, absolute TVR rates were 15.2 per 100 DES patients and 24.1 per 100 BMS patients, and as a result, cumulative TVR-related costs were $2065 less per patient for DES versus BMS ($3001 less to $1134 less). Including the cost of clopidogrel, the incremental cost-effectiveness ratio per TVR avoided with DES was $4731 through 1 year, $4703 through 2 years, and $6379 through 3 years.

CONCLUSIONS

At 3 years, the higher index cost of DES versus BMS was completely offset by lower TVR-related costs. However, because of extended clopidogrel use for DES, the incremental cost-effectiveness ratio per TVR avoided ranged from $4703 to $6379 over 3 years. These unadjusted observational findings provide support for the continued use of DES in routine practice but highlight the important impact of prolonged dual antiplatelet use on the cost-effectiveness of this technology.

Mechanisms of nonfatal acute myocardial infarction late after stent implantation: the relative impact of disease progression, stent restenosis, and stent thrombosis

BACKGROUND

The impact of stent restenosis, stent thrombosis, or progression of disease at another site as responsible mechanisms of acute myocardial infarction (AMI) after stent implantation is not clear.

METHODS

By searching our catheterization laboratory database for a 4-year period, 91 cases of nonfatal AMI at least 1 month after stent implantation (32.6% drug-eluting stents) were identified. By detailed comparison of post-AMI with the initial percutaneous coronary intervention angiogram, the mechanism of AMI was analyzed.

RESULTS

Acute myocardial infarction was attributed to disease progression at another site in 42 (46.2%), stent restenosis in 35 (38.4%), and stent thrombosis in 10 (11%) cases. The AMI mechanism could be either stent related or disease progression (nonidentifiable culprit lesion) in 4 cases (4.4%). The median time from percutaneous coronary intervention to AMI was 27, 19, and 9 months for disease progression at another site, restenosis, and stent thrombosis group, respectively (P = .03). ST-elevation myocardial infarction occurred in 38.1% of the disease progression, in 20% of the restenosis, and in 60% of the stent thrombosis cases (P = .046).

CONCLUSIONS

In a "real world" population, late after stent implantation, a patient has an almost equal probability to have suffered a nonfatal AMI from either stent restenosis/thrombosis or disease progression at another site. Continuous research efforts are necessary to equally address both stent therapy and disease progression.

Impact of small thrombus formation in restenotic bare-metal stent lesions associated with acute coronary syndrome: identification by optical coherence tomography

BACKGROUND

Although in-stent restenosis (ISR) after bare-metal stent (BMS) implantation is considered to be clinically benign, ISR is often associated with adverse complications, such as acute coronary syndrome (ACS). The frequency, type, and location of thrombi in ISR lesions and their clinical presentation have not yet been precisely validated.

METHODS

Thirty angiographic ISR lesions occurring within 3 to 8 months after stenting were evaluated by optical coherence tomography (OCT). A thrombus was defined as a mass protruding into the lumen with an irregular surface, and its type was divided into red or white. The maximum size of a thrombus and the longitudinal distance from the thrombus to the narrowest lumen were measured.

RESULTS

A thrombus was identified in 2 patients by angiography and in 10 patients by OCT (7% vs. 33%; P=0.01). OCT showed that 9 patients had white thrombus and another patient had both types of thrombi. ACS relevant to ISR was seen in 6 patients, and the frequency of ACS was significantly higher in patients with thrombus than in those without thrombus [50% (5/10) vs. 5% (1/20); P=0.003]. The maximum size of the thrombus was 412 ± 220 µm in height, 424 ± 251 µm in width, and the longitudinal distance between the thrombus and the minimum lumen area was 0.3 ± 0.7 mm.

CONCLUSIONS

One third of ISR lesions following BMS deployment dominantly contained a white thrombus, and half of them were associated with ACS. A small thrombus formation adjacent to the narrowest lumen in an ISR lesion may therefore contribute to the clinical presentation of ACS.

Promoting Vascular Regeneration as an Alternative to Conventional Angioplasty-Based Intervention

Technologies in interventional Cardiology have evolved from balloon to mechanical ablation, atherectomy, stenting, and brachytherapy to current drug eluting interventional strategies. New challenges are to develop techniques that not only prevent restenosis, but also promote vascular and endothelial healing after (balloon) injury. Endothelial healing approaches range from preventing endothelial injury to restoring endothelial function and reendothelialization by pharmacotherapy and cell therapy. These novel healing strategies warrant further exploration as they may represent an alternative to drug-eluting stent approaches.

Cost-effectiveness of drug-eluting stents in a US Medicare setting:a cost-utility analysis with 3-year clinical follow-up data

BACKGROUND

There is only limited information about cost-effectiveness of drug-eluting compared with bare metal stents (BMS) over a time horizon of more than 1 year.

METHODS AND RESULTS

We developed a Markov model based on clinical outcome data from a meta-analysis including 17 randomized controlled trials comparing drug-eluting versus BMS with a minimum follow-up of 1 (n = 8221) and a maximum follow-up of 3 years (n = 4105) in patients with chronic coronary artery disease. Costs were obtained as reimbursement rates for diagnosis related groups from the US Centers for Medicare and Medicaid Services. All costs and effects were discounted at 3% annually. All costs are reported in US dollars of the financial year 2007. The incremental effects are 0.002 (95% confidence interval −0.039 to 0.041) quality-adjusted life-years (QALYs) for the sirolimus- and −0.001 (−0.040 to 0.038) QALYs for the paclitaxel-eluting stents (PES). The incremental costs are $2790 for the sirolimus- and $3838 for the PES. The incremental cost-effectiveness ratio is >$1,000,000 per QALY for the sirolimus-eluting stent. PES are dominated by BMS (i.e., less effective and more costly). Among various sensitivity analyses performed, the model proved to be robust.

CONCLUSIONS

Our analysis from a US Medicare perspective suggests that drug-eluting stents are not cost-effective compared with BMS when implanted in unselected patients with symptomatic ischemic coronary artery disease.

Diagnostic accuracy of 64-slice multidetector CT for detection of in-stent restenosis in an unselected, consecutive patient population

OBJECTIVES

To investigate the diagnostic accuracy of 64-slice multidetector computed tomography (64-CT) for detection of in-stent restenosis (ISR) in an unselected, consecutive patient population.

BACKGROUND

Detection of in-stent restenosis by cardiac CT would be a major advance for the evaluation of patients suspected of having ISR. However, the diagnostic accuracy of current generation 64-CT in this context is not fully established.

METHODS

We conducted a prospective study on patients with stable angina or acute coronary syndrome with no prior history of coronary artery disease. Six months after percutaneous coronary intervention (PCI) with stent placement they underwent a 64-CT scan (Toshiba Multi-Slice Aquilion 64) and consequently a repeat coronary angiography for comparison. Cardiac CT data sets were analyzed for the presence of in-stent restenosis by two independent expert readers blinded to the coronary angiographic data.

RESULTS

Ninety-three patients with a total of 140 stents were evaluated. Males comprised 82% of the study group and the mean age was 63±10 years. The mean time from PCI to the repeat coronary angiography was 208±37 days and the mean time from 64-CT to repeat coronary angiography was 3.7±4.9 days. The restenosis rate according to coronary angiography was 26%. Stent diameter, strut thickness, heart rate and body mass index (BMI) significantly affected image quality. The sensitivity, specificity, positive and negative predictive values of 64-CT for detection of in-stent restenosis were 27%, 95%, 67% and 78%, respectively.

CONCLUSIONS

Current generation, 64-slice CT, remains limited in its ability to accurately detect in-stent restenosis.

Microvolt T-wave alternans and the selective use of implantable cardioverter defibrillators for primary prevention: A cost-effectiveness study

Objectives:Implantable cardioverter defibrillators (ICDs) are an effective but expensive treatment for the prevention of sudden cardiac deaths in patients with severe left-ventricular dysfunction. Recent studies suggest that microvolt T-wave alternans (MTWA) predicts mortality and severe arrhythmic events in this population. However, the impact of MTWA on ICD cost-effectiveness is unknown.

Methods:A Markov decision-analysis model evaluated three treatment strategies for primary prevention in patients with severe left-ventricular dysfunction: (i) medical therapy for all; (ii) ICD therapy for all; and (iii) selective ICD therapy based on non-negative (positive or indeterminate) MTWA test results. Incremental cost-effectiveness ratios (ICER) were calculated from the perspective of a third party payer using a 10-year time horizon. Sensitivity analyses examined the robustness of the estimates.

Results:A treatment strategy involving ICD therapy in all patients was associated with an ICER of $121,800/quality-adjusted life-year (QALY) compared with medical therapy, whereas a treatment strategy involving the selective use of ICDs based on MTWA test results was associated with an ICER of $108,900/QALY compared with medical therapy. Sensitivity analyses suggest that, under most scenarios, the selective use of ICDs based on MTWA results does not decrease the ICER to below $100,000/QALY.

Conclusion:MTWA only marginally improves the cost-effectiveness of ICDs for primary prevention in patients with severe left-ventricular dysfunction. There remains a need for improved means to effectively identify which patients will derive the greatest benefit from ICD implantation.

Economic evaluation of drug-eluting stents compared to bare metal stents using a large prospective study in Ontario

Objectives:To determine the cost-effectiveness (CE) and cost-utility (CU) of drug-eluting stents (DES) compared to bare metal stents (BMS) in Ontario using a large prospective “real-world” cohort study and determine the extent to which results vary by patient risk subgroups.

Methods:A field evaluation was conducted based on all stent procedures in the province of Ontario between December 1, 2003, and March 31, 2005, with a minimum subject follow-up of 1 year. Effectiveness data from the study using a propensity-score matched cohort were combined with resource utilization and cost data and quality of life (QOL) data from the published literature in a decision analytic modeling framework to determine 2-year cost-effectiveness (cost per revascularization avoided) and cost-utility (cost per quality-adjusted life-year ([QALY] gained). Stochastic model parameter uncertainty was expressed using probability distributions and analyzed using a probabilistic model. Modeling assumptions were assessed using traditional deterministic sensitivity analysis.

Results:Significant differences in revascularization rates were found for patients with two or more high risk factors. Despite these differences, the CE and CU of DES remained high (e.g., $419,000 per QALY gained in the most favorable patient risk subgroup). In sensitivity analysis, the difference in cost between DES and BMS had an impact on the CE and CU results. For example, at a price differential of $500, the CU of DES was $20,000/QALY for one patient subgroup and DES was dominant (i.e., less costly and more effective) in another.

Conclusions:At current prices, the CE/CU of DES compared with BMS is high even in patient high risk subgroups. As the relative price of DES decrease, the value for money attractiveness of DES increases, especially for selected high risk patients.

Cost-effectiveness of drug-eluting stents including the economic impact of late stent thrombosis

Recent studies examining the effectiveness of drug-eluting stents (DES) have found that the use of DES is associated with a significant increase in the incidence of late stent thrombosis (LST). Previous cost-effectiveness analyses of DES have not accounted for the costs associated with LST. In this study, published research was reviewed to identify studies that compared the cost-effectiveness of DES with that of bare-metal stents and to identify the incidence of LST. Probable costs were assigned to LST-related myocardial infarction and death on the basis of the treatment costs for these outcomes. These costs as well as those of extended clopidogrel therapy were then incorporated into the Sirolimus-Eluting Balloon Expandable Stent in the Treatment of Patients With De Novo Native Coronary Artery Lesions (SIRIUS) and TAXUS-IV cost-effectiveness data. This review found that the incidence of LST ranged from 0.2% to 0.7%. Assuming a base case LST incidence of 0.5%, a cost per death of $20,000, a cost per myocardial infarction of $20,000, and a cost of an additional 2 years of clopidogrel therapy of $2,428 per patient, the costs per revascularization avoided were $15,056 for the SIRIUS trial and $25,210 for the TAXUS-IV trial. The costs per quality-adjusted life-year gained were $250,935 and $257,591, respectively. Sensitivity analyses revealed that the costs per revascularization avoided varied from $14,618 to $15,830 for the SIRIUS trial and from $24,540 to $26,396 for the TAXUS-IV trial. Similarly, the cost per quality-adjusted life-year gained varied from $243,638 to $263,840 for the SIRIUS trial and from $250,739 to $269,708 for the TAXUS-IV trial. In conclusion, LST-related adverse events and the need for extended clopidogrel therapy substantially increase the costs associated with the implementation of DES. The inclusion of these costs renders the widespread use of DES not cost effective in the United States in terms of cost per quality-adjusted life-year gained and cost per revascularization avoided.

Cost effectiveness of drug-eluting stents in Belgian practice: healthcare payer perspective

BACKGROUND

There has been a steep increase in the number of percutaneous coronary intervention procedures performed for coronary heart disease since their introduction about 30 years ago. Recently, the use of drug-eluting stents (DES) compared with the original bare metal stents (BMS) has increased in many countries.

OBJECTIVE

To assess the cost effectiveness of DES versus BMS in a real-world setting from the Belgian healthcare payer perspective.

METHODS

We developed a decision analysis model to estimate incremental costs (year 2004 or 2007 values [depending on the underlying variable]) and effectiveness. Incremental effectiveness was calculated by combining relative benefits from published meta-analyses with real-world observations from a Belgian registry. Probabilistic modelling and sensitivity analyses were performed. The model had a 1-year time horizon. Sixteen sub groups were created based on the following characteristics: initial stent type, diabetic status, complex lesion and multi-vessel disease. Scenario analyses were performed for the influence on reinterventions and the duration of clopidogrel use. In each analysis, 1000 Monte Carlo simulations were performed.

RESULTS

The incremental costs for switching from BMS to DES are substantial (approximately euro1000), while the benefits, expressed as QALYs, are extremely small (on average <0.001 QALYs gained). This led to very high incremental cost-effectiveness ratios: over euro860 000 per QALY gained in all subgroups and scenario analyses.

CONCLUSION

Comparing DES with BMS, no life-years are gained and small quality-of-life improvements are achieved for short periods, resulting in a high likelihood that DES are not cost effective. When there is competition for scarce resources this should be considered when deciding on the reimbursement of this technology.

Disparity in drug-eluting stent utilization by insurance type

BACKGROUND

Because of the expense of drug-eluting stents (DES) and associated adjuvant therapy, nonclinical, socioeconomic factors may be associated with DES use in clinical practice.

METHODS

Data on 112,588 patients from the National Cardiovascular Data CathPCI Registry (NCDR) between 2004 and 2005 with "on-label" indications for DES were analyzed. Insurance status was categorized as No Insurance, Governmental, and Private Insurance. Hierarchical multivariable logistic regression analyses were used to evaluate the association between insurance status and DES use, after adjusting for patient and procedural characteristics.

RESULTS

Drug-eluting stent use was >96% during the study period, with utilization significantly associated with insurance status. Compared with patients with Private Insurance, patients with No Insurance (odds ratio 0.44, 95% confidence interval 0.37-0.53) and Government Insurance (odds ratio 0.73, 95% confidence interval 0.67-0.80) were significantly less likely to receive a DES than a bare metal stent. Repeat analysis of patients <65 years of age demonstrated virtually identical results.

CONCLUSIONS

Despite the high penetration of DES, significant associations between insurance status and DES utilization were identified. This indicates that disparities in health care based on socioeconomic factors extend to DES utilization and highlights the need to address such disparities as novel therapies emerge.

A strategy to offset the extra cost of sirolimus-eluting stent in patients undergoing intervention for acute myocardial infarction

OBJECTIVE

To obtain a quantitative estimate of the overall costs and cost effectiveness ratio of sirolimus-eluting stents (SES) implantation and tirofiban infusion compared to abciximab and bare metal stent (BMS) in patients undergoing primary intervention for acute ST segment elevation myocardial infarction (STEMI).

METHODS

In the attempt to make the unrestricted use of SES in STEMI patients affordable under the current European reimbursement system, between March 6, 2003, and April 23, 2004, 175 patients with STEMI were randomized to receive tirofiban infusion and SES versus abciximab and BMS as part of the STRATEGY trial. Costs and outcome were monitored for 2 years.

RESULTS

The cost of the index procedure was 9345 euros +/-2573 and 9657+/-2114 for the tirofiban+SES and abciximab+BMS group, respectively (P=0.048). At follow-up, the composite of death or myocardial infarction and the costs not related to target vessel revascularisation (TVR) did not differ in the two groups while the rate of TVR and the costs related to it were lower in the tirofiban+SES group. The overall 2-year cost of treating a patient in the tirofiban+SES group was 10,971 euros +/-4185 compared to 12,066 euros +/-4636 for the abciximab+BMS group (P=0.006). Halving the cost of abciximab resulted in higher initial hospital costs for the tirofiban+SES but overall cost neutrality over a 24-month time horizon.

CONCLUSIONS

Compared to abciximab+BMS, tirofiban infusion+SES implantation in STEMI patients was an economically dominant strategy, with an improved composite outcome and lower overall costs.

Cost-effectiveness of drug-eluting stents in patients at high or low risk of major cardiac events in the Basel Stent KostenEffektivitäts Trial (BASKET): an 18-month analysis

BACKGROUND

Our aim was to determine whether drug-eluting stents are good value for money in long-term, everyday practice.

METHODS

We did an 18-month cost-effectiveness analysis of the Basel Stent KostenEffektivitäts Trial (BASKET), which randomised 826 patients 2:1 to drug-eluting stents (n=545) or to bare-metal stents (281). We used non-parametric bootstrap techniques to determine incremental cost-effectiveness ratios (ICERs) of drug-eluting versus bare-metal stents, to compare low-risk (> or =3.0 mm stents in native vessels; n=558, 68%) and high-risk patients (<3.0 mm stents/bypass graft stenting; n=268, 32%), and to do sensitivity analyses by altering costs and event rates in the whole study sample and in predefined subgroups. Quality-adjusted life-years (QALYs) were assessed by EQ-5D questionnaire (available in 703/826 patients).

FINDINGS

Overall costs were higher for patients with drug-eluting stents than in those with bare-metal stents (11,808 euros [SD 400] per patient with drug-eluting stents and 10,450 euros [592] per patient with bare-metal stents, mean difference 1358 euros [717], p<0.0001), due to higher stent costs. We calculated an ICER of 64,732 euros to prevent one major adverse cardiac event, and of 40,467 euros per QALY gained. Stent costs, number of events, and QALYs affected ICERs most, but unrealistic alterations would have been required to achieve acceptable cost-effectiveness. In low-risk patients, the probability of drug-eluting stents achieving an arbitrary ICER of 10,000 euros or less to prevent one major adverse cardiac event was 0.016; by contrast, it was 0.874 in high-risk patients.

INTERPRETATION

If used in all patients, drug-eluting stents are not good value for money, even if prices were substantially reduced. Drug-eluting stents are cost effective in patients needing small vessel or bypass graft stenting, but not in those who require large native vessel stenting.

Effectiveness and safety of drug-eluting stents in Ontario

BACKGROUND

The placement of drug-eluting stents decreases the frequency of repeat revascularization procedures in patients undergoing percutaneous coronary intervention (PCI) in randomized clinical trials. However, there is uncertainty about the effectiveness of drug-eluting stents, and increasing concern about their safety, in routine clinical practice.

METHODS

From the Cardiac Care Network of Ontario's population-based clinical registry of all patients undergoing PCI in Ontario, Canada, we identified a well-balanced cohort of 3751 pairs of patients, matched on the basis of propensity score, who received either bare-metal stents alone or drug-eluting stents alone during an index PCI procedure between December 1, 2003, and March 31, 2005. The primary outcomes of the study were the rates of target-vessel revascularization, myocardial infarction, and death.

RESULTS

The 2-year rate of target-vessel revascularization was significantly lower among patients who received drug-eluting stents than among those who received bare-metal stents (7.4% vs. 10.7%, P<0.001). Drug-eluting stents were associated with significant reductions in the rate of target-vessel revascularization among patients with two or three risk factors for restenosis (i.e., presence of diabetes, small vessels [<3 mm in diameter], and long lesions [> or =20 mm]) but not among lower-risk patients. The 3-year mortality rate was significantly higher in the bare-metal-stent group than in the drug-eluting-stent group (7.8% vs. 5.5%, P<0.001), whereas the 2-year rate of myocardial infarction was similar in the two groups (5.2% and 5.7%, respectively; P=0.95).

CONCLUSIONS

Drug-eluting stents are effective in reducing the need for target-vessel revascularization in patients at highest risk for restenosis, without a significantly increased rate of death or myocardial infarction.

Impact of in-stent restenosis on death and myocardial infarction

Although drug-eluting stents reduce restenosis and target lesion revascularization compared with bare metal stents (BMSs), the specter of late stent thrombosis has curbed enthusiasm for the widespread use of drug-eluting stents. Alternatively, increasing BMS use would increase restenosis and potentially increase adverse events. The presentation and outcomes of BMS restenosis are controversial. We evaluated 2,539 patients with BMS restenosis referred for repeat revascularization. Major adverse cardiac events, including mortality and myocardial infarction (MI), were assessed at clinical presentation, 30 days, and 6 months. Patients with acute presentation (i.e., unstable angina requiring hospitalization or MI) were compared with patients with stable presentation. At presentation, 19.2% of patients were asymptomatic, 27.5% had exertional angina, 46.6% had unstable angina, and 6.7% had MI. Mortality and MI rates were 1.1% and 1.4%, respectively, at 30 days and 3.3% and 4.5%, respectively, at 6 months. Patients with acute coronary syndrome (ACS) and those without ACS had similarly low mortality rates at 30 days (1.2% ACS vs 1.0% non-ACS, p = 0.65) and 6 months (3.4% ACS vs 3.3% non-ACS, p = 0.93) and MI rates at 30 days (1.3% ACS vs 1.4% non-ACS, p = 0.87) and 6 months (4.7% ACS vs 4.3% non-ACS, p = 0.65). Combined major adverse cardiac events were similar at 30 days (2.5% vs 2.1%, p = 0.53) and 6 months (7.4% ACS vs 6.9%, non-ACS, p = 0.65). In conclusion, although BMS restenosis often manifests as an ACS, it is associated with a low incidence of 6-month major adverse cardiac events and does not predict a negative outcome.

The pathophysiology and burden of restenosis

The introduction of percutaneous transluminal coronary angioplasty (PTCA) revolutionized the surgical treatment of coronary artery disease. However, despite increased surgical experience and technical breakthroughs, restenosis occurs in 30%-50% of patients undergoing simple balloon angioplasty and in 10%-30% of patients who receive an intravascular stent. Animal and human data indicate that restenosis is a response to injury incurred during PTCA. The need for reintervention in a high percentage of patients due to restenosis remains an important limitation to the long-term success of PTCA. Stenting reduces initial elastic recoil and limits negative arterial remodeling; however, bare-metal stents may promote intimal hyperplasia by eliciting an immune and proliferative response. Consistent with these data, clinical studies suggest that drug-eluting stents, coated with anti-inflammatory or antiproliferative agents, reduce the risk for restenosis. Stenting represents a considerable cost burden. Treatment strategy should focus on selective use of expensive drug-eluting stents in populations where they have been found to be more clinically effective than bare-metal stents--patients who are at high risk for restenosis or who develop restenosis with bare-metal stents. Recent studies suggest that the pharmacologic management of restenosis is now feasible. Together, the judicious use of stents and oral pharmacotherapy promise to reduce the risk for restenosis, even among high-risk patients.

Understanding the drug-eluting stent trials

The advent of intravascular stenting dramatically reduced the incidence of restenosis among patients undergoing percutaneous transluminal coronary angioplasty. However, a substantial percentage of patients, particularly those with risk factors such as diabetes mellitus or complicated lesions, remain at risk for restenosis. Drug-eluting stents overcome this problem by releasing bioactive agents from a polymeric coating directly into the vessel wall, inhibiting the cellular mechanisms of restenosis while avoiding systemic toxicity. Recent data indicate that local targeting of the proliferative process with drug-eluting stents dramatically reduces the risk for restenosis, even among high-risk patients. A range of bioactive coatings are currently available or in late clinical trials. Both sirolimus- and paclitaxel-eluting stents have demonstrated efficacy in a broad range of patient types; early data from clinical trials of second-generation stent coatings, such as everolimus and ABT-578 (zotarolimus), suggest that these agents are also effective in preventing restenosis. This article reviews the pathophysiology of in-stent restenosis and surveys recent key clinical trials of drug-eluting stents.

A tale of two stents: perioperative management of patients with drug-eluting coronary stents

Drug-eluting stents were introduced into clinical practice to decrease coronary stent restenosis rates. Though remarkably effective in reducing this complication, recent data reveal that drug-eluting stents pose a significant risk for late stent thrombosis, an event strongly correlated with discontinuation of anti-platelet therapy. Because anti-platelet agents are often discontinued perioperatively, patients with DES are at risk for perioperative stent thrombosis and myocardial infarction. Along with a review of the recent literature, we present two cases of patients with drug-eluting stents scheduled for renal transplantation. Two distinct antithrombotic management strategies illustrate the risk of either approach-bleeding and transfusion versus stent thrombosis and myocardial infarction.

The costs and quality-of-life outcomes of drug-eluting coronary stents: a systematic review

OBJECTIVES

While the efficacy of drug-eluting coronary stents (DES) has been demonstrated by several clinical trials, the impact of DES on health-care costs and recipient quality of life (QOL) is controversial. We performed a systematic review of the published literature on DES costs and the QOL effects of restenosis and target vessel revascularization (TVR).

METHODS

Among 536 potential articles initially identified by a broad search, 12 publications ultimately met inclusion criteria. Data were independently abstracted, evaluated for quality and relevance, and summarized by two reviewers. Excessive heterogeneity among these studies prevented formal meta-analysis, thus a narrative synthesis of the literature was performed.

RESULTS

In four economic studies, DES recipients had 1,600 dollars-3,200 dollars higher up-front costs than recipients of bare metal stents, but the differences in total costs after 1 year were less pronounced (200 dollars-1,200 dollars), and estimates of the average cost of an avoided revascularization ranged widely (1,800 dollars-36,900 dollars). All eight QOL studies indicated that restenosis was associated with lower QOL, but only two studies quantified this in terms of quality-adjusted life years (QALYs), with estimates ranging from 0.06 to 0.08. An additional study estimated that the median willingness to pay to prevent restenosis was 2,400 dollars-3,600 dollars.

CONCLUSIONS

There is a lack of convergence in the literature on the cost of DES in avoiding TVR. There is more agreement that the average QALY benefit of an avoided revascularization is 0.04-0.08. This implies that use of DES in patients where the average cost per avoided revascularization exceeds 8,000 dollars may be less likely to be cost-effective.

Effect of hospital ownership status and payment structure on the adoption and use of drug-eluting stents for percutaneous coronary interventions

BACKGROUND

The impact of the use of drug-eluting stents in percutaneous coronary intervention (PCI) on cardiac care is still uncertain. We examined the influence of systemic factors, such as hospital ownership status, organizational characteristics and payment structure, on the use of drug-eluting stents in PCI and the effect on cardiac surgery volume.

METHODS

We conducted a cross-sectional analysis of drug-eluting stent use in 12 993 patients undergoing PCI with stenting (drug-eluting or bare-metal) and time-series regression analyses of the monthly number of cardiac surgery and PCI procedures performed using data collected from 1998 to 2004 at 13 public and private hospitals in the Emilia-Romagna region of Italy.

RESULTS

Public hospitals used drug-eluting stents more selectively than private hospitals, targeting the new device to patients at high risk of adverse events. The time-series regression analyses showed that the number of PCI procedures performed per year increased during this period, both in public (slope coefficient 36.4, 95% confidence interval [CI] 30.2 to 43.1) and private centres (slope coefficient 6.4, 95% CI 3.1 to 9.2 ). Concurrently, there was a reduction in the number of isolated coronary artery bypass graft (CABG) surgeries, although the degree of change was higher in public than in private hospitals (coefficient -16.1 v. -6.2 respectively ). The number of CABG procedures associated with valve surgery decreased in public hospitals (coefficient -5.0, 95% CI -6.1 to -3.8) but increased in private hospitals (coefficient 4.1, 95% CI 2.0 to 6.1).

INTERPRETATION

Public and private hospitals behaved differently in adopting drug-eluting stents and in using PCI with drug-eluting stents as a substitute for surgical revascularization.

The cost-effectiveness of drug-eluting stents: a systematic review

BACKGROUND

Drug-eluting stents have been seen as an attractive alternative to bare-metal stents for percutaneous coronary interventions (PCIs) because of the decreased need for revascularization. However, comparative clinical trials have shown no difference in patient outcomes, and drug-eluting stents are considerably more expensive than their bare-metal counterparts. We conducted a systematic review of all published comparative cost-effectiveness analyses to identify the factors contributing to the heterogeneity of their conclusions.

METHODS

We retrieved all articles published between Jan. 1, 2000, and July 31, 2006, in which the cost-effectiveness, from a third-party payer perspective, of drug-eluting stents was compared with that of bare-metal stents for PCI in unrestricted patient populations. Electronic databases, Web sites from health technology assessment groups and references of identified articles were searched. Our outcome variable was whether the study's conclusions favoured widespread use of drug-eluting stents, as assessed by 4 independent reviewers. Study characteristics such as quality, funding source, country and year of publication were extracted. Two-by-2 tables and Fisher's exact test were used to study the association between covariates and the outcome variable. A classification and regression tree (CART) model was used for multivariate analysis.

RESULTS

We identified 19 cost-effectiveness analyses. Ten were in favour of widespread use of drug-eluting stents, and 9 favoured more restrained use. Only 1 of 9 high-quality studies supported widespread use, as compared with 9 of 10 lower quality studies (p < 0.001). All of the 7 sponsored studies argued in favour of widespread use, as compared with 3 of the 12 studies without sponsorship (p = 0.003). Studies from the United States were more likely than those from other countries to endorse unlimited use (p = 0.032). A CART model with 2 covariates--study quality and sponsorship--provided the best fit (error rate 10.5%).

INTERPRETATION

Conclusions drawn by cost-effectiveness analyses of drug-eluting stents for PCI are associated with the study's quality, funding source and country of origin. Vigilance regarding these study characteristics is required when interpreting findings from cost-effectiveness analyses.

Efficacy and Safety of Drug-Eluting Stents: Current Best Available Evidence

The development of drug-eluting coronary stents has proved to be a quantum advance in interventional cardiology, rivaling the impact of stenting itself. Drug-eluting coronary stents deliver effective local concentrations of antiproliferative drugs (thus avoiding systemic toxicities), without substantially modifying the technique of percutaneous coronary intervention. Studies involving several different stent platforms and antiproliferative drug coatings have recently demonstrated dramatic reductions in restenosis rates, compared to conventional bare metal stents. Although the clinical benefits of drug-eluting stents are increasingly evident, important concerns about their long-term safety and costs have been raised. Furthermore, drug-eluting stents are being claimed to replace coronary artery bypass surgery in the near future. This review article evaluates the current best available evidence on the efficacy and safety of drug-eluting stents with a focus on the impact of this "revolutionary" new technology on the practice of coronary artery bypass surgery.

Simultaneous double-culprit in-stent thrombosis. Who is the guilty prisoner behind bars: drug-eluting stent, bare-metal stent, or indication for treatment?

BACKGROUND

The intrinsic thrombogeneity of stents was the historic limitation to their usage during the early phases of stenting. The risk of stent thrombosis has been minimized by the widespread use of platelet antiaggregation. Nowadays, the risk of subacute stent thrombosis is around 1%. Thrombotic risk depends on several factors, such as type of stent, complexity of lesion, and clinical picture.

CASE REPORT

We present a case of recurrent acute in-stent thrombosis in a patient with mild antithrombin III (AT) deficiency despite the combined administration of clopidogrel and aspirin.

CONCLUSION

In our patient, several factors, such as diabetes, AT deficiency, and the use of a paclitaxel-eluting stent, have contributed to the development of recurrent acute stent thrombosis. Although we were not able to identify the culprit factor, we should keep in mind that the deployment of a drug-eluting stent could be unsafe if it is not supported by a clear clinically oriented pathway that considers the overall condition of the patient since, in some cases, neither coronary lesions nor coronary stents are responsible for the negative outcome of patient therapy, which may be caused instead by incomplete or inadequate patient assessment.

Cost Analysis From Two Randomized Trials of Sirolimus-Eluting Stents Versus Paclitaxel-Eluting Stents in High-Risk Patients With Coronary Artery Disease

OBJECTIVES

This study sought to analyze the cost of percutaneous coronary interventions with use of sirolimus-eluting stents (SES) or paclitaxel-eluting stents (PES) in patients at high risk of restenosis.

BACKGROUND

Recent studies have shown different clinical efficacy with these drug-eluting stents. Whether this difference extends on cost estimates between the 2 stents is not known.

METHODS

We included 450 patients with diabetes mellitus and in-stent restenosis from 2 randomized studies comparing SES with PES. Assigned costs for the economic evaluation were the initial hospitalization and all subsequent cardiac-related inpatient/outpatient health resources during 9 to 12 months of clinical follow-up. The economic evaluation was performed from the health insurance system's perspective.

RESULTS

There were no differences between the 2 study groups regarding mortality (p = 0.78) and myocardial infarction rates (p = 0.76). Target lesion revascularization was performed in 16 patients (7.1%) in the SES group and in 34 patients (15.1%) in the PES group (p = 0.01). Initial hospital costs were not significantly different between the 2 stents (p = 0.53). The follow-up costs were, however, different: 2,684 +/- 2,072 euros per patient treated with SES and 4,527 +/- 6,466 euros per patient treated with PES (p < 0.001). Total costs also differed at the end of the follow-up: 8,924 +/- 3,077 euros per patient treated with SES and 10,903 +/- 7,205 euros per patient treated with PES (p < 0.001).

CONCLUSIONS

In patients at high risk of restenosis, use of SES is associated with lower costs compared with PES. The cost savings are mainly due to the reduced need of repeat revascularization procedures with SES.

Cost effectiveness of paclitaxel-eluting stents for patients undergoing percutaneous coronary revascularization: results from the TAXUS-IV Trial

OBJECTIVES

This study sought to compare aggregate medical care costs for patients undergoing percutaneous coronary intervention with paclitaxel-eluting stents (PES) and bare-metal stents (BMS) and to formally evaluate the incremental cost effectiveness of PES for patients undergoing single-vessel percutaneous coronary intervention.

BACKGROUND

Although the cost effectiveness of SES has been studied in both clinical trials and decision-analytic models, few data exist on the cost effectiveness of alternative drug-eluting stent (DES) designs. In addition, no clinical trials have specifically examined the cost effectiveness of DES among patients managed without mandatory angiographic follow-up.

METHODS

We performed a prospective economic evaluation among 1,314 patients undergoing percutaneous coronary revascularization randomized to either PES (N = 662) or BMS (N = 652) in the TAXUS-IV trial. Clinical outcomes, resource use, and costs (from a societal perspective) were assessed prospectively for all patients over a 1-year follow-up period. Cost effectiveness was defined as the incremental cost per target vessel revascularization (TVR) event avoided and was analyzed separately among cohorts assigned to mandatory angiographic follow-up (n = 732) or clinical follow-up alone (n = 582).

RESULTS

The PES reduced TVR by 12.2 events per 100 patients treated, resulting in a 1-year cost difference of 572 dollars per patient with incremental cost-effectiveness ratios of 4,678 dollars per TVR avoided and 47,798 dollars/quality-adjusted life year (QALY) gained. Among patients assigned to clinical follow-up alone, the net 1-year cost difference was 97 dollars per patient with cost-effectiveness ratios of 760 dollars per TVR event avoided and $5,105/QALY gained.

CONCLUSIONS

In the TAXUS-IV trial, treatment with PES led to substantial reductions in the need for repeat revascularization while increasing 1-year costs only modestly. The cost-effectiveness ratio for PES in the study population compares reasonably with that for other treatments that reduce coronary restenosis, including alternative drug-eluting stent platforms.

Bare metal stent restenosis is not a benign clinical entity

BACKGROUND

Restenosis after percutaneous coronary intervention (PCI) has been thought to present in a stable manner as exertional angina. However, the presentation of in-stent restenosis (ISR) is not well-studied. We hypothesized that a substantial proportion of bare metal ISR presents as acute coronary syndromes. We aimed to characterize the severity of the clinical presentation of ISR.

METHODS

We searched our PCI database for all cases of PCI for bare metal ISR occurring between May 1999 and September 2003. Multivessel interventions were excluded. In-stent restenosis presentation was classified into three categories: (1) myocardial infarction (MI), (2) unstable angina requiring hospitalization before angiography, and (3) exertional angina. Routine angiographic screening after initial stent placement was not performed, so ISR episodes were clinical, rather than angiographic, ISR.

RESULTS

We identified 1186 cases of bare metal ISR in 984 patients. Median age was 63, 72% were male, and 36% had diabetes. Of the ISR episodes, 9.5% presented as acute MI (7.3% as non-ST-segment elevation MI and 2.2% as ST-segment elevation MI), 26.4% as unstable angina requiring hospitalization before angiography, and 64.1% as exertional angina.

CONCLUSIONS

More than one third of bare metal ISR episodes presented as MI or unstable angina requiring hospitalization. The acuity of the clinical presentation of bare metal ISR appears to be more severe than has been previously thought. Aggressive efforts, such as drug-eluting stents to decrease the incidence of unstable angina due to bare metal ISR, are warranted.

Sirolimus-eluting coronary stents in small vessels

BACKGROUND

This prospective multicenter study compared angiographic in-lesion late lumen loss in de novo native coronary artery lesions (vessel diameter range 2.25-2.75 mm, length range > or = 15 to < or = 30 mm) 8 months after the implantation of a sirolimus-eluting stent with that of similar vessels with the same drug-eluting stent or a bare stent of the SIRIUS study (historical controls).

METHODS AND RESULTS

One hundred one patients (study group) were matched and compared with 323 patients receiving the bare stent (bare control group) and with 350 receiving the Cypher stent (Cypher control group) in the SIRIUS trial. Mean in-lesion late loss in the study group was lower than that in the bare control group (0.20 versus 0.76 mm, P < .0001) and not inferior to that in the Cypher control group (0.27 mm, P = .3). Adverse event rates (death and myocardial infarction) were similar between groups. At 8 months, target lesion revascularization rates were 0% in the study group, 13.2% in the bare control group (P < .001), and 4.6% in the Cypher control group (P = .03).

CONCLUSIONS

The Cypher Bx Velocity stent was confirmed to be superior to the bare Bx Velocity stent in small coronary vessels in terms of in-lesion late loss 8 months after implantation.

Decision models for assessing the cost effectiveness of drug-eluting stents

Percutaneous coronary intervention is an increasingly common treatment for many people with coronary disease. Randomised trials using antiproliferative, drug-eluting stents (DES) have shown important reductions in the need for repeat procedures after initial percutaneous coronary intervention. These trials indicate that the growing use of DES has the potential to create major clinical benefits for patients; however, in actual practice, the associated costs may cause financial crises for hospital systems. This paper reviews previously published DES economic decision models from both societal and hospital perspectives. From a social perspective, additional spending for new technologies may be acceptable if these technologies convincingly improve the lives of patients. The models reviewed suggest that DES incurs large costs to both society and hospitals, and currently offers uncertain clinical benefits. More research is recommended to identify high-risk patients who stand to gain significant health benefits from this therapy.

Restenosis related to percutaneous coronary intervention has been solved?

Percutaneous coronary intervention (PCI) has become the most important revascularization method in the treatment of coronary artery disease. The major problem in PCI has been renarrowing of the dilated vessel after the procedure (restenosis). The best results in the prevention of restenosis have been obtained by covering the stent with drugs that inhibit cellular growth, thus limiting excessive scar formation inside of the stent. With drug-eluting stents, restenosis has been reduced to one-tenth compared with balloon angioplasty and to one-fourth compared to bare metal stents. Due to drug-eluting stents, PCI is an alternative to bypass surgery. However, restenosis will remain a challenge due to the increased number of procedures and more difficult disease treated with PCI.