Temporal changes in coronary revascularization procedures, outcomes, and costs in the bare-metal stent and drug-eluting stent eras: results from the US Medicare program

Updated estimates of large and medium vessel strokes, mechanical thrombectomy trends, and future projections indicate a relative flattening of the growth curve but highlight opportunities for expanding endovascular stroke care

BACKGROUND

A study was undertaken to determine the incidence of acute ischemic stroke (AIS) and strokes related to large (LVO) and medium (MVO) vessel occlusions, and to estimate annual mechanical thrombectomy (MT) volume, past trends and future growth.

METHODS

A population-based analysis was performed to estimate the rate of AIS, LVOs (internal carotid artery terminus, M1 branch of the middle cerebral artery, basilar artery) and MVOs (M2 and M3 branches of the middle cerebral artery, anterior and posterior cerebral arteries). MT estimates were determined from multiple governmental data sources. Annual US numbers were adjusted for population growth.

RESULTS

The incidence of AIS is estimated at 216 (95% CI 199 to 238)/100 000 persons/year or 718 191 (95% CI 661 483 to 791 121) AIS/year in the USA. A vascular occlusion was observed in 21% of patients with AIS (95% CI 15 to 29). The rate of LVO was 24/100 000 persons/year (95% CI 19 to 31) or 80 075 (95% CI 62 457 to 104 375) LVOs/year, and the rate of MVO was 20/100 000 persons/year or 65 798 (95% CI 45 555 to 95 110) MVOs/year. MT estimates for 2021 are 39 164 procedures with a flattening of the growth curve from 2019 (9%, 2020-2021; 4%, 2019-2020) as opposed to initial steep growth from 2015 to 2018. Current MT procedures represent 5% of all AIS, 27% of all vascular occlusions (LVO+MVO) and 38% of all LVO and M2 occlusions. The current trajectory indicates a future growth of 5-10%/year for the next several years.

CONCLUSION

A decline in MT growth is observed. The incidence of LVO+MVO is estimated at 44/100 000 persons/year or almost 144 000 large and medium vessel strokes annually. Of these, currently an estimated 27% undergo an MT procedure, indicating an opportunity for growth. Further expansion may require focusing on the elderly, medium vessel strokes and workflow efficiencies from diagnosis to treatment.

Annual case volume on mortality after coronary artery bypass grafting: a dose-response meta-analysis

OBJECTIVES

This study evaluated the effect of both hospital and surgeon annual case volumes on patient mortality following coronary artery bypass grafting (CABG).

METHODS

PubMed and Embase databases were searched for clinical studies on CABG. The outcome was mortality, including operative mortality, in-hospital mortality and 30-day mortality.

RESULTS

Twenty-five studies involving 3 492 101 participants and 143 951 deaths were included for hospital volume, and 4 studies involving 108 356 participants and 2811 deaths were included for surgeon volume. The pooled estimate revealed that both hospital and surgeon annual case volumes were inversely associated with mortality in patients after CABG [odds ratio (OR) for hospital: 0.62, 95% confidence interval (CI) 0.56-0.69; P < 0.001; OR for surgeon: 0.51, 95% CI 0.31- 0.83; P < 0.001] with high heterogeneity (hospital: I2 = 90.6%, Pheterogeneity < 0.001; surgeon: I2 = 86.8%, Pheterogeneity < 0.001). The relationship remained consistent and robust in most subgroup and sensitivity analyses. Our meta-regression analysis of time suggested that the strength of the negative associations between volume and mortality for both hospitals and surgeons remained unattenuated over time even though the CABG mortality gradually decreased over time. The dose-response analysis suggested a non-linear relationship between both hospital and surgeon annual case volumes and mortality (both Pnon-linearity = 0.001).

CONCLUSIONS

Both higher hospital and surgeon annual case volumes are associated with lower mortality in patients undergoing CABG, and the negative associations remain unattenuated over time.

CLINICAL REGISTRATION NUMBER

The study was registered at PROSPERO as CRD42017067912.

Comparison of plaque morphology between peripheral and coronary artery disease (from the CLARITY and ADAPT-DES IVUS substudies)

OBJECTIVE

The aim of this study was to help understand the different outcomes when treating peripheral arterial disease (PAD) versus coronary artery disease (CAD). We compared plaque morphology between PAD and CAD using intravascular ultrasound.

METHODS

Complete Lesion Assessment with ffR and IVUS TechnologY (CLARITY) was a prospective, multicenter trial that enrolled 50 PAD patients with a lower extremity wound fed by a tibial or a peroneal artery with diameter stenosis more than 50%. Assessment of Dual AntiPlatelet Therapy With Drug Eluting Stents (ADAPT-DES) was a prospective, multicenter, registry that enrolled 8582 CAD patients. We compared preintervention intravascular ultrasound findings in 42 PAD lesions from CLARITY versus 79 matched CAD lesions from ADAPT-DES.

RESULTS

Compared with CAD lesions, PAD lesions had (i) smaller mean vessel, plaque, and lumen volumes; (ii) twice the lesion length; (iii) greater maximum superficial calcium arc and plaque eccentricity (i.e. there was more concentric plaque) measured at the minimum lumen area site; (iv) calcium arc and plaque eccentricity were positively correlated to plaque burden in both PAD and CAD lesions; and (v) calcium arc and the presence of concentric plaque were greater in PAD compared with CAD independent of the degree of plaque burden.

CONCLUSION

Compared with CAD lesions, PAD lesions in a tibial or a peroneal artery were longer; had more concentric, diffuse, and calcified plaque; and had smaller vessel volumes.

In vivo Molecular Imaging of Glutamate Carboxypeptidase II Expression in Re-endothelialisation after Percutaneous Balloon Denudation in a Rat Model

The short- and long-term success of intravascular stents depends on a proper re-endothelialisation after the intervention-induced endothelial denudation. The aim of this study was to evaluate the potential of in vivo molecular imaging of glutamate carboxypeptidase II (GCPII; identical with prostate-specific membrane antigen PSMA) expression as a marker of re-endothelialisation. Fifteen Sprague Dawley rats underwent unilateral balloon angioplasty of the common carotid artery (CCA). Positron emission tomography (PET) using the GCPII-targeting tracer [¹⁸F]DCFPyL was performed after 5-21 days (scan 60-120 min post injection). In two animals, the GCPII inhibitor PMPA (23 mg/kg BW) was added to the tracer solution. After PET, both CCAs were removed, dissected, and immunostained with the GCPII specific antibody YPSMA-1. Difference of GCPII expression between both CCAs was established by PCR analysis. [¹⁸F]DCFPyL uptake was significantly higher in the ipsilateral compared to the contralateral CCA with an ipsi-/contralateral ratio of 1.67 ± 0.39. PMPA blocked tracer binding. The selective expression of GCPII in endothelial cells of the treated CCA was confirmed by immunohistological staining. PCR analysis verified the site-specific GCPII expression. By using a molecular imaging marker of GCPII expression, we provide the first non-invasive in vivo delineation of re-endothelialisation after angioplasty.

Trends and Hospital Variations in Surgical Outcomes for Cholangiocarcinoma in New York State

BACKGROUND

This population-based study examined surgical outcomes and hospital and post-acute care resource use after operations of cholangiocarcinoma during 2005-2012.

STUDY DESIGN

Using New York State hospital claims, we identified subjects with intrahepatic tumor who underwent hepatectomy only (n = 2089), subjects with perihilar tumor who underwent hepatectomy and biliary-enteric anastomosis (BEA; n = 389) or BEA only (n = 3721), and subjects with distal cholangiocarcinoma undergoing pancreatectomy or pancreaticoduodenectomy (n = 228). We performed trend analyses for each group and calculated overall risk-adjusted mortality, complication, and 30-day readmission rates for hospitals using multivariable logistic regressions.

RESULTS

Mortality rate was roughly 12 % over years for perihilar cases undergoing hepatectomy and BEA, significantly higher than the rates of other 3 groups (p = 0.000). The overall complication rate was 40 % for subjects undergoing both hepatectomy and BEA, more than doubling the rate for subjects undergoing hepatectomy or BEA alone (p = 0.000). Average LOS declined markedly for perihilar cases undergoing hepatectomy and BEA (from 21 days in 2005 to 16 days in 2012) and subjects with distal cholangiocarcinoma (from 22 days in 2005 to 16 days in 2012), but other outcomes did not change dramatically. Risk-adjusted hospital outcome rates varied substantially.

CONCLUSIONS

Surgical patients with cholangiocarcinoma incur considerable mortality, postoperative complications, and resource uses, especially among those undergoing hepatectomy and BEA for perihilar tumors.

Patient-level costs of major cardiovascular conditions: a review of the international literature

OBJECTIVE

Robust cost estimates of cardiovascular (CV) events are required for assessing health care interventions aimed at reducing the economic burden of major adverse CV events. This review synthesizes international cost estimates of CV events.

METHODS

MEDLINE database was searched electronically for English language studies published during 2007-2012, with cost estimates for CV events of interest - unstable angina, myocardial infarction, heart failure, stroke, and CV revascularization. Included studies provided at least one estimate of patient-level direct costs in adults for any identified country. Information on study characteristics and cost estimates were collected. All costs were adjusted for inflation to 2013 values.

RESULTS

Across the 114 studies included, the average cost was US $6,466 for unstable angina, $11,664 for acute myocardial infarction, $11,686 for acute heart failure, $11,635 for acute ischemic stroke, $37,611 for coronary artery bypass graft, and $13,501 for percutaneous coronary intervention. The ranges for cost estimates varied widely across countries with US cost estimate being at least twice as high as European Union costs for some conditions. Few studies were found on populations outside the US and European Union.

CONCLUSION

This review showed wide variation in the cost of CV events within and across countries, while showcasing the continuing economic burden of CV disease. The variability in costs was primarily attributable to differences in study population, costing methodologies, and reporting differences. Reliable cost estimates for assessing economic value of interventions in CV disease are needed.

A population-based incidence of acute large vessel occlusions and thrombectomy eligible patients indicates significant potential for growth of endovascular stroke therapy in the USA

BACKGROUND

Data on large vessel strokes are important for resource allocation and infrastructure development.

OBJECTIVE

To determine an annual incidence of large vessel occlusions (LVOs) and a thrombectomy eligible patient population.

METHODS

All patients with acute ischemic stroke discharged over 3 years from a tertiary-level hospital serving a large geographic area were evaluated for an LVO (M1, internal carotid artery terminus, basilar artery). The incidence of LVO was determined for the hospital's 4-county primary service area (PSA, population 210 000) based on each county's discharges and extrapolated to the US population. 'Thrombectomy eligibility' for anterior circulation LVOs was based on time (onset <6 hours) and imaging (Alberta Stroke Program Early CT Score (ASPECTS) ≥6). The number of annual thrombectomy procedures was calculated for Medicare and private payer patients using federally available databases.

RESULTS

1157 patients were discharged from the hospital's PSA, of whom 129 (11.1%, 95% CI 9.5% to 13.1%) had an LVO. This translated into an LVO incidence of 24 per 100 000 people per year (95% CI 20 to 28). 20 per 100 000 people per year had anterior circulation LVOs (95% CI 19 to 22), of whom 10/100 000/year (95% CI 8 to 11) were 'thrombectomy eligible'. An additional 5/100 000/year (95% CI 3 to 6) presented with favorable ASPECTS after 6 hours of symptom onset. Basilar occlusion incidence was estimated at 4/100 000/year (95% CI 2 to 5). These rates yield 77 569 (95% CI 65 835 to 91 091) new LVOs per year in the USA. An estimated 10 284 mechanical thrombectomy procedures were performed in 2015.

CONCLUSIONS

This study estimates an LVO incidence of 24 per 100 000 person-years (95% CI 20 to 28). A current estimated annual thrombectomy rate of three procedures per 100 000 people indicates significant potential increase in the volume of endovascular procedures and the need to develop systems of care.

Changes in the Practice of Coronary Revascularization between 2006 and 2010 in the Republic of Korea

PURPOSE

Evidence suggests that technological innovations and reimbursement schemes of the National Health Insurance Service may have impacted the management of coronary artery disease. Thus, we investigated changes in the practice patterns of coronary revascularization.

MATERIALS AND METHODS

Revascularization and in-hospital mortality among Koreans ≥20 years old were identified from medical claims filed between 2006 and 2010. The age- and sex-standardized procedure rate per 100,000 person-years was calculated directly from the distribution of the 2008 Korean population.

RESULTS

The coronary revascularization rate increased from 116.1 (95% confidence interval, 114.9-117.2) in 2006 to 131.0 (129.9-132.1) in 2010. Compared to the rate ratios in 2006, the rate ratios for percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) surgery in 2010 were 1.16 (1.15-1.17) and 0.80 (0.76-0.84), respectively. Among patients who received PCI, the percentage with drug-eluting stents increased from 89.1% in 2006 to 93.0% in 2010. In-hospital mortality rates from PCI significantly increased during the study period (p=0.03), whereas those from CABG significantly decreased (p=0.01). The in-hospital mortality rates for PCI and CABG were higher in elderly and female patients and at the lowest-volume hospitals.

CONCLUSION

The annual volume of coronary revascularization continuously increased between 2006 and 2010 in Korea, although this trend differed according to procedure type. A high percentage of drug-eluting stent procedures and a high rate of in-hospital mortality at low-volume hospitals were noted.

Acute coronary syndromes in the community

OBJECTIVES

To measure the incidence of acute coronary syndrome (ACS), defined as first-ever myocardial infarction (MI) or unstable angina (UA); evaluate recent temporal trends; and determine whether survival after ACS has changed over time and differs by type.

PATIENTS AND METHODS

This was a population surveillance study conducted in Olmsted County, Minnesota (population: 144,248). All persons hospitalized with incident ACS between January 1, 2005, and December 31, 2010, were identified using International Classification of Diseases, Ninth Revision codes, natural language processing of the medical records, and biomarkers. Myocardial infarction was validated by epidemiologic criteria and UA by the Braunwald classification. Patients were followed through June 30, 2013, for death.

RESULTS

Of 1244 incident ACS cases, 35% (n=438) were UA and 65% (n=806) were MI. The standardized rates (per 100,000) of ACS were 284 (95% CI, 248-319) in 2005 and 184 (95% CI, 157-210) in 2010 (2010 vs 2005: rate ratio, 0.62; 95% CI, 0.53-0.73), indicating a 38% decline (similar for MI and UA). The 30-day case fatality rates did not differ by year of diagnosis but were worse for MI (8.9%; 95% CI, 6.9%-10.9%) compared with UA (1.9%; 95% CI, 0.6%-3.1%). Among 30-day survivors, the risk of death did not differ by ACS type or diagnosis year.

CONCLUSION

In the community, UA constitutes 35% of ACS. The incidence of ACS has declined in recent years, and trends were similar for UA and MI, reaffirming a substantial decline in all acute manifestations of coronary disease. Survival after ACS did not change over time, but 30-day survival was worse for MI compared with UA.

Impact of drug-eluting stents on the comparative effectiveness of coronary artery bypass surgery and percutaneous coronary intervention

BACKGROUND

Drug-eluting stents (DES) have largely replaced bare-metal stents (BMS) for percutaneous coronary intervention (PCI). It is uncertain, however, whether introduction of DES had a significant impact on the comparative effectiveness of PCI versus coronary artery bypass graft surgery (CABG) for death and myocardial infarction (MI).

METHODS

We identified Medicare beneficiaries aged ≥66 years who underwent multivessel CABG or multivessel PCI and matched PCI and CABG patients on propensity score. We defined the BMS era as January 1999 to April 2003 and the DES era as May 2003 to December 2006. We compared 5-year outcomes of CABG and PCI using Cox proportional hazards models, adjusting for baseline characteristics and year of procedure and tested for a statistically significant interaction (P(int)) of DES era with treatment (CABG or PCI).

RESULTS

Five-year survival improved from the BMS era to the DES era by 1.2% for PCI and by 1.1% for CABG, and the CABG:PCI hazard ratio was unchanged (0.90 vs 0.90; P(int) = .96). Five-year MI-free survival improved by 1.4% for PCI and 1.1% for CABG, with no change in the CABG:PCI hazard ratio (0.81 vs 0.82; P(int) = .63). By contrast, survival-free of MI or repeat coronary revascularization improved from the BMS era to the DES era by 5.7% for PCI and 0.9% for CABG, and the CABG:PCI hazard ratio changed significantly (0.50 vs 0.57, P(int) ≤ .0001).

CONCLUSIONS

The introduction of DES did not alter the comparative effectiveness of CABG and PCI with respect to hard cardiac outcomes.

Hospitalization costs for acute myocardial infarction patients treated with percutaneous coronary intervention in the United States are substantially higher than Medicare payments

BACKGROUND

Acute coronary syndromes account for half of all deaths secondary to cardiovascular disease and represent a significant economic burden in the United States. Therefore, assessing hospitalization costs relative to Medicare reimbursement for these patients is important in understanding the impact of these patients on hospitals. We hypothesized that hospitalization costs for acute myocardial infarction patients treated with percutaneous coronary intervention (PCI) were higher than their associated Medicare payments.

METHODS

Using the Nationwide Inpatient Sample, we evaluated hospitalization costs for patients treated with PCI from 2001 through 2009 by multiplying hospital charges by the group average cost-to-charge ratio for each patient's hospitalization. Primary end points examined were total hospital costs and trends over time, which were correlated with clinical outcomes and insurance payments. Costs were inflation adjusted with 2009 as the reference year.

RESULTS

Median hospitalization costs of PCI increased from $15 889 (interquartile range [IQR] = $12 057-$21 204) in 2001 to $19 349 (IQR = $14 660-$26 282) in 2009. From 2004 to 2009, inflation-adjusted costs for PCI decreased at a rate of 0.3% per year. In 2009, a total of 265,531 patients received PCI for acute myocardial infarction. Of these, 143 654 were <65 years old, and 121 876 were ≥65 years old. Average 2009 Medicare payments ranged from $9303 to $17 500 depending on the Medicare Severity-Diagnosis Related Groups (MS-DRG) billed, leaving hospitals at a loss of anywhere from $4493 to $7940 per patient when comparing costs and reimbursements across all included MS-DRG codes.

CONCLUSIONS

Hospitalization costs for patients treated with PCI have been stabilizing over the last few years; however, there still remains a significant disparity between Medicare reimbursements and hospitalization costs, which has potential implications on patient outcomes, quality of care, and hospital sustainability.

Rate of percutaneous coronary intervention for the management of acute coronary syndromes and stable coronary artery disease in the United States (2007 to 2011)

Although the benefit of percutaneous coronary interventions (PCIs) for patients presenting with acute coronary syndromes (ACS) has been established in numerous studies, the role of PCI in stable coronary artery disease (CAD) remains controversial. With the publication of the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluations trial and the appropriate use criteria for coronary artery revascularization, we sought to examine the impact of these treatment strategies and guidelines on the current practice of PCI in United States. We conducted a serial cross-sectional study with time trends of patients undergoing PCI for ACS and stable CAD from 2007 to 2011. The annual rate of all PCI decreased by 27.7% from 10,785 procedures per million adults per year in 2007 to 2008 to 7,801 procedures per million adults per year in 2010 to 2011 (p=0.03). Although there was no statistically significant decrease in the PCI utilization for ACS from 2007 to 2011, PCI utilization for stable CAD decreased by 51.7% (from 2,056 procedures per million adults per year in 2008 to 992 procedures per million adults per year in 2011, p=0.02). Hospitals with a higher volume of PCI experienced a more significant decrease. Decrease in PCI utilization for stable CAD was statistically significant for patients with Medicare and private insurance/health maintenance organization (44.5%, p=0.03 and 59.5%, p=0.007, respectively). In conclusion, the rate of PCI decreased substantially starting from 2009 in the United States. Most of the decrease was attributed to the reduction in PCI utilization for stable CAD.

Predicting target vessel revascularization in older patients undergoing percutaneous coronary intervention in the drug-eluting stent era

BACKGROUND

The contemporary need for repeat revascularization in older patients after percutaneous coronary intervention (PCI) has not been well studied. Understanding repeat revascularization risk in this population may inform treatment decisions.

METHODS

We analyzed patients ≥65 years old undergoing native-vessel PCI of de novo lesions from 2005 to 2009 discharged alive using linked CathPCI Registry and Medicare data. Repeat PCIs within 1 year of index procedure were identified by claims data and linked back to CathPCI Registry to identify target vessel revascularization (TVR). Surgical revascularization and PCIs not back linked to CathPCI Registry were excluded from main analyses but included in sensitivity analyses. Independent predictors of TVR after drug-eluting stent (DES) or bare-metal stent (BMS) implantation were identified by multivariable logistic regression.

RESULTS

Among 343,173 PCI procedures, DES was used in 76.5% (n = 262,496). One-year TVR ranged from 3.3% (overall) to 7.1% (sensitivity analysis). Precatheterization and additional procedure-related TVR risk models were developed in BMS (c-indices 0.54, 0.60) and DES (c-indices 0.57, 0.60) populations. Models were well calibrated and performed similarly in important patient subgroups (female, diabetic, and older [≥75 years]). The use of DES reduced predicted TVR rates in high-risk older patients by 35.5% relative to BMS (from 6.2% to 4.0%). Among low-risk patients, the number needed to treat with DES to prevent 1 TVR was 63-112; among high-risk patients, this dropped to 28-46.

CONCLUSIONS

In contemporary clinical practice, native-vessel TVR among older patients occurs infrequently. Our prediction model identifies patients at low versus high TVR risk and may inform clinical decision making.

Spatial Sufficiency of 5% Medicare Standard Analytic Files

The 5% Medicare Standard Analytic Files (SAF) are random samples used to analyze national trends in medical treatments, expenditures, and outcomes. Their utility in small-area or multilevel analyses is unknown. To demonstrate possible limitations of the 5% SAF for analysis of health behaviors in small areas. We use descriptive Chi-square goodness-of-fit tests and mapping to explore consistency in the 5% representation of the 100% population in states and counties. We conduct multilevel modeling of individual utilization of mammography or endoscopy services for cancer screening and contrast findings across the 5% and 100% files. Subjects are enrolled in both parts A and B Medicare coverage and ages 65-104, alive and residing in the same state, with no gaps in coverage during the study period. Identically defined groups are drawn from the 5% SAF and 100% population claims and denominator files. The Chi-square tests of homogeneous population subgroups in 5% and 100% files exhibit significant differences in 7 of 8 states. Maps confirm this among states' counties and find that one state is generally under-represented by the 5% SAF, while others show areas with variable representation. Multilevel modeling results are largely consistent across the partitions of the data, but 5% sample models have much lower statistical power. Area-level covariate effect estimates show some differences across the two datasets. Multilevel modeling with contextual variables may be misleading in small area analyses conducted using 5% Medicare SAFs. Provider supply and market characteristics show inconsistent results. Disparities research may benefit from 100% files to provide statistical power needed to detect meaningful differences. This is significant because the Centers for Medicare and Medicaid Services have recently curtailed permissions to use the 100% files. These 100% files are one of few sources of population data available in the U.S. that are representative of small areas in the U.S.. In times of constrained budgets, using population data files is essential so that resources can be targeted to areas robustly identified as having greatest need or gaps in outcomes.

External adjustment sensitivity analysis for unmeasured confounding: an application to coronary stent outcomes, Pennsylvania 2004-2008

BACKGROUND

Assessing the real-world comparative effectiveness of common interventions is challenged by unmeasured confounding.

OBJECTIVE

To determine whether the mortality benefit shown for drug-eluting stents (DES) over bare metal stents (BMS) in observational studies persists after controls for/tests for confounding.

DATA SOURCES/STUDY SETTING

Retrospective observational study involving 38,019 patients, 65 years or older admitted for an index percutaneous coronary intervention receiving DES or BMS in Pennsylvania in 2004-2005 followed up for death through 3 years.

STUDY DESIGN

Analysis was at the patient level. Mortality was analyzed with Cox proportional hazards models allowing for stratification by disease severity or DES use propensity, accounting for clustering of patients. Instrumental variables analysis used lagged physician stent usage to proxy for the focal stent type decision. A method originating in work by Cornfield and others in 1954 and popularized by Greenland in 1996 was used to assess robustness to confounding.

PRINCIPAL FINDINGS

DES was associated with a significantly lower adjusted risk of death at 3 years in Cox and in instrumented analyses. An implausibly strong hypothetical unobserved confounder would be required to fully explain these results.

CONCLUSIONS

Confounding by indication can bias observational studies. No strong evidence of such selection biases was found in the reduced risk of death among elderly patients receiving DES instead of BMS in a Pennsylvanian state-wide population.

Pathologic Etiologies of Late and Very Late Stent Thrombosis following First-Generation Drug-Eluting Stent Placement

Several randomized and observational studies have reported steady increase in cumulative incidence of late and very late ST (LST/VLST) following first-generation drug-eluting stents (DES: sirolimus-(SES) and paclitaxel-(PES)) up to 5 years. Pathologic studies have identified uncovered struts as the primary substrate responsible for LST/VLST following DES, where delayed arterial healing is associated with stent struts penetrating into the necrotic core, long/overlapping stents, and bifurcation stenting especially in flow divider region. Grade V stent fracture also induces LST/VLST and restenosis. Hypersensitivity reaction is exclusive to SES as an etiology of LST/VLST, whereas malapposition secondary to excessive fibrin deposition is associated with PES. Uncovered struts can be identified in SES and PES with duration of implant beyond 12 months, particularly in stents placed for "off-label" indications. Neoatherosclerosis is another important contributing factor for VLST in DES and bare metal stents (BMS); however, DES shows rapid and more frequent development of neoatherosclerosis than BMS. Future pathologic studies should address the long-term safety of newer generation DES including zotarolimus- and everolimus-eluting stents in terms of the improvement in reendothelialization, decreased inflammation and fibrin deposition as well as a lower incidence of stent fracture-related adverse events, and reduced neoatherosclerosis, which likely contribute to the decreased risk of LST/VLST and better patient outcomes.

The importance of the endothelium in atherothrombosis and coronary stenting

Deployment of drug-eluting stents instead of bare-metal stents has dramatically reduced restenosis rates, but rates of very late stent thrombosis (>1 year postimplantation) have increased. Vascular endothelial cells normally provide an efficient barrier against thrombosis, lipid uptake, and inflammation. However, endothelium that has regenerated after percutaneous coronary intervention is incompetent in terms of its integrity and function, with poorly formed cell junctions, reduced expression of antithrombotic molecules, and decreased nitric oxide production. Delayed arterial healing, characterized by poor endothelialization, is the primary cause of late (1 month-1 year postimplantation) and very late stent thrombosis following implantation of drug-eluting stents. Impairment of vasorelaxation in nonstented proximal and distal segments of stented coronary arteries is more severe with drug-eluting stents than bare-metal stents, and stent-induced flow disturbances resulting in complex spatiotemporal shear stress can also contribute to increased thrombogenicity and inflammation. The incompetent endothelium leads to late stent thrombosis and the development of in-stent neoatherosclerosis. The process of neoatherosclerosis occurs more rapidly, and more frequently, following deployment of drug-eluting stents than bare-metal stents. Improved understanding of vascular biology is crucial for all cardiologists, and particularly interventional cardiologists, as maintenance of a competently functioning endothelium is critical for long-term vascular health.

Trends in the use of diagnostic coronary angiography, percutaneous coronary intervention, and coronary artery bypass graft surgery across North Carolina

BACKGROUND

Although variation in use of invasive coronary procedures has been shown, the relationship between invasive diagnostic cardiac catheterization (Cath) and subsequent revascularization with percutaneous coronary intervention (PCI) or coronary artery bypass surgery (CABG) is not known. We evaluated the temporal trends and variation in invasive Cath, PCI, and CABG across hospital systems in North Carolina.

METHODS

All Cath, PCI, and CABG procedures performed in North Carolina from 2003 to 2009 were identified using data reported in the annual North Carolina State Medical Facilities Plan. Rates and variation in procedure use, relative rates of PCI to Cath, CABG to Cath, and CABG to PCI were compared over the study period between hospitals that performed at least 25 Cath, 25 PCI, and 25 CABG procedures.

RESULTS

The rates of all invasive procedures per 100,000 population declined: 24% for Cath, 16% for PCI, and 35% for CABG. However, the relative rate of PCI to Cath over the study period increased by 11%, whereas the relative rate of CABG to Cath decreased by 13%. Hospital level analysis showed significant variation in the relative rate of both PCI to Cath (10%-90%, P < .05) and CABG to Cath (5%-35%, P < .05).

CONCLUSIONS

Although the use of all invasive cardiac procedures declined, the relative rate of PCI to Cath increased over the study period. There was also significant variation in the mode of revascularization (CABG and PCI) across hospital systems in North Carolina. Further research is needed to understand drivers of coronary revascularization.

Comparison between sirolimus- and paclitaxel-eluting stents for the treatment of older patients affected by coronary artery disease: results from a single-center allcomers registry

The treatment of elderly patients with coronary artery disease (CAD) is challenging because this population is complex and greatly expanding. Drug-eluting stents (DES) generally improve the outcome in high-risk cases. We evaluated the clinical impact of different first-generation DES, i.e., sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES), in this context. A prospective, nonrandomized, single-center, allcomers registry consecutively enrolling all patients aged ≥75 years eligible for percutaneous coronary intervention (PCI) with DES was carried out. Only one type of DES was implanted per protocol for each patient. Two groups were identified according to the type of implanted stent, i.e., SES and PES. The primary end point encompassed major adverse cardiac events (MACE), including death, myocardial infarction, and target lesion revascularization (TLR). The secondary end point encompassed the rate of definite/probable stent thrombosis and target vessel revascularization (TVR). From June 2004 to May 2008, 151 patients were enrolled. Among them, 112 (74.2%) received SES and 39 (25.8%) received PES. Baseline clinical characteristics were similar, while few angiographic features (ostial location, stent diameter, proximal reference vessel diameter) showed minor differences. At the median follow-up of 22.6 months, primary and secondary end points did not significantly differ in terms of MACE (SES 12.5% vs PES 20.5%, P = 0.3), death (SES 5.4% vs PES 7.7%, P = 0.7), myocardial infarction (SES 4.5% vs PES 10.3%, P = 0.2), TLR (SES 2.7% vs PES 2.6%, P = 1.0), stent thrombosis (SES 1.8% vs PES 5.1%, P = 0.3), and TVR (SES 1.8% vs PES 0%, P = 0.6). In this real-world population of elderly patients treated by DES-PCI for CAD, the overall efficacy and safety have been excellent in both DES, and the choice between SES and PES did not influence the clinical outcome.

Long-term impact of Medicare managed care on patients treated for coronary artery disease

BACKGROUND

Planned health insurance reform promises and has started to cut reimbursement to Medicare managed care (MMC) plans. If such plans provide better care, adjusting for possible better health of their enrollees, then such reimbursement changes may have unforeseen quality consequences.

OBJECTIVES

To examine whether long-term follow-up outcomes of patients who receive intensive interventional care for coronary artery disease differed by Medicare plan type.

RESEARCH DESIGN

Patient-level postdischarge outcomes were multivariate adjusted logistic functions of a patient's insurance type at time of index admission. Data were retrospective secondary percutaneous coronary intervention data from Pennsylvania with 35,417 index admissions in 2004 to 2005 and in-state follow-up hospitalizations within 12 months and in-state death within 3 years of discharge.

RESULTS

MMC insured patients had a consistently estimated 3-year survival benefit (relative risk of death 0.91; P value 0.003) compared with traditional Medicare traditional fee for service patients. Results were robust to propensity score stratification, subset analyses, and rich controls for observed confounders. Implausibly large associations (between an unmeasured confounder and both insurance status and outcomes) would have to be hypothesized to fully explain the observed survival benefit.

CONCLUSIONS

Among a large number of Pennsylvanian elderly patients, receiving a very common therapeutic procedure for highly prevalent disease, being insured with MMC was associated with a clinically meaningful long-term survival benefit. Impending health insurance reform that changes the relative attractiveness of MMC plans may have unintended consequences on outcome quality.

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.

Clinical characteristics and outcomes of Medicare patients undergoing total hip arthroplasty, 1991-2008

CONTEXT

Total hip arthroplasty is a common surgical procedure but little is known about longitudinal trends.

OBJECTIVE

To examine demographics and outcomes of patients undergoing primary and revision total hip arthroplasty.

DESIGN, SETTING, AND PARTICIPANTS

Observational cohort of 1,453,493 Medicare Part A beneficiaries who underwent primary total hip arthroplasty and 348,596 who underwent revision total hip arthroplasty. Participants were identified using International Classification of Diseases, Ninth Revision, Clinical Modification codes for primary and revision total hip arthroplasty between 1991 and 2008.

MAIN OUTCOME MEASURES

Changes in patient demographics and comorbidity, hospital length of stay (LOS), mortality, discharge disposition, and all-cause readmission rates.

RESULTS

Between 1991 and 2008, the mean age for patients undergoing primary total hip arthroplasty increased from 74.1 to 75.1 years and for revision total hip arthroplasty from 75.8 to 77.3 years (P < .001). The mean number of comorbid illnesses per patient increased from 1.0 to 2.0 for primary total hip arthroplasty and 1.1 to 2.3 for revision (P < .001). For primary total hip arthroplasty, mean hospital LOS decreased from 9.1 days in 1991-1992 to 3.7 days in 2007-2008 (P = .002); unadjusted in-hospital and 30-day mortality decreased from 0.5% to 0.2% and from 0.7% to 0.4%, respectively (P < .001). The proportion of primary total hip arthroplasty patients discharged home declined from 68.0% to 48.2%; the proportion discharged to skilled care increased from 17.8% to 34.3%; and 30-day all-cause readmission increased from 5.9% to 8.5% (P < .001). For revision total hip arthroplasty, similar trends were observed in hospital LOS, in-hospital mortality, discharge disposition, and hospital readmission rates.

CONCLUSION

Among Medicare beneficiaries who underwent primary and revision hip arthroplasty between 1991 and 2008, there was a decrease in hospital LOS but an increase in the rates of discharge to postacute care and readmission.

Trends in coronary revascularization in the United States from 2001 to 2009: recent declines in percutaneous coronary intervention volumes

BACKGROUND

There is speculation that the volume of percutaneous coronary interventions (PCIs) has been decreasing over the past several years. Published studies of PCI volume have evaluated regional or hospital trends, but few have captured national data. This study describes the use of coronary angiography and revascularization methods in Medicare patients from 2001 to 2009.

METHODS AND RESULTS

This retrospective study used data from the Centers for Medicare & Medicaid Services from 2001 to 2009. The annual number of coronary angiograms, PCI, intravascular ultrasound, fractional flow reserve, and coronary artery bypass graft (CABG) surgery procedures were determined from billing data and adjusted for the number of Medicare recipients. From 2001 to 2009, the average year-to-year increase for PCI was 1.3% per 1000 beneficiaries, whereas the mean annual decrease for CABG surgery was 5%. However, the increase in PCI volume occurred primarily from 2001 to 2004, as there was a mean annual rate of decline of 2.5% from 2004 to 2009; similar trends were seen with diagnostic angiography. The use of intravascular ultrasound and fractional flow reserve steadily increased over time.

CONCLUSIONS

This study confirms recent speculation that PCI volume has begun to decrease. Although rates of CABG have waned for several decades, all forms of coronary revascularization have been declining since 2004.

Barriers to implementation of workplace health interventions: an economic perspective

OBJECTIVE

To identify insurance related, structural, and workplace cultural barriers to the implementation of effective preventive and upstream clinical interventions in the working age adult population.

METHODS

Analysis of avoided costs from perspective of health economics theory and from empiric observations from large studies; presentation of data from our own cost-plus model on integrating health promotion and ergonomics.

RESULTS

We identify key avoided costs issues as a misalignment of interests between employers, insurers, service institutions, and government. Conceptual limitations of neoclassical economics are attributable to work culture and supply-driven nature of health care.

DISCUSSION

Effective valuation of avoided costs is a necessary condition for redirecting allocations and incentives. Key content for valuation models is discussed.

Drug-eluting stents in the elderly

OPINION STATEMENT

The introduction of drug-eluting stents (DES) in 2003 has had a great impact on the management of coronary artery disease in the United States. The application of DES to older adults, the population with the highest prevalence of and worst prognosis for coronary artery disease, remains relatively more controversial. Dual-antiplatelet therapy, which is recommended for at least 12 months after DES placement, is particularly problematic for older patients because of greater age-related bleeding risks. Unfortunately, few current data are available to gauge the balance of risk and benefit in elderly community-dwelling DES patients. Although trial data show a benefit for DES among elderly patients, many older adults typically are excluded from randomized trials because of comorbidities, making generalizability of DES safety based on trial data less certain. New, more potent thienopyridines may place the elderly at a particularly elevated bleeding risk. There is a fine balance between efficacy and safety for older DES patients that still needs to be clarified. As the population ages, these issues become more pervasive and of widespread concern. This review summarizes the current literature on DES therapy in the elderly, with a focus on effectiveness and safety profiles of DES versus bare metal stents.

Temporal trends in revascularization and outcomes after acute myocardial infarction among the very elderly

BACKGROUND

Few data are available on time-related changes in use and outcomes of invasive procedures after acute myocardial infarction in very elderly patients. Our objective was to describe trends in revascularization procedures and outcomes in a provincial cohort of very elderly patients who had experienced acute myocardial infarction.

METHODS

We used a database of hospital discharge summaries to identify all patients aged 80 years or older admitted for acute myocardial infarction in Quebec. We used the provincial database of physicians' services and medication claims to assess treatment and obtain data on survival.

RESULTS

Between March 1996 and March 2007, 29 750 patients aged 80 years or older were admitted to hospital for acute myocardial infarction. During this period, use of percutaneous coronary interventions increased from 2.2% to 24.9%, and use of coronary artery bypass graft surgery increased from 0.8% to 3.1%. Evidence-based prescriptions of medication increased over time (p < 0.001). The prevalence of reported comorbidities was higher during the period of 2003-2006 than during the 1996-1999 period. One-year mortality improved over time (46.5% for 1996-1999 v. 40.9% for 2003-2006, p < 0.001) but remained unchanged in the subgroup of patients who did not undergo revascularization.

INTERPRETATION

The use of revascularization, especially percutaneous coronary interventions, in the very elderly after acute myocardial infarction has been growing at a rapid pace, while the prevalence of reported comorbidities has been increasing in this population. Revascularization procedures are no longer restricted to younger patients. In the context of an aging population, it is imperative to determine whether these changes in practice are cost-effective.

Effect of drug-eluting stents on frequency of repeat revascularization in patients with unstable angina pectoris or non-ST-elevation myocardial infarction

Drug-eluting stents (DES) have been shown to markedly reduce the need for repeat revascularization compared to bare-metal stents in patients with stable coronary artery disease. The benefit of DES in patients with acute coronary syndromes (ACS) is unclear. This analysis was undertaken to determine if DES have similar advantages over bare-metal stents in patients with ACS. A cohort of 3,771 patients underwent percutaneous coronary intervention with stent implantation in native coronary arteries. Patients presenting for primary angioplasty or rescue angioplasty were excluded. Patients were classified as having stable or unstable symptoms on presentation and then further divided by stent type, DES or bare-metal stent. Although there was a difference in efficacy, with fewer major adverse cardiac events after DES implantation for the stable patients at 1 year (8.2% vs 13.2%, p = 0.008), this benefit was not found in patients with ACS (11.2% vs 12.0%, p = 0.6). A reduced need for repeat revascularization of the initially treated artery accounted for this difference (5.6% vs 11.4%, p <0.001). Stent thrombosis by 1 year was equally rare with each stent type. In conclusion, the reduction in the need for repeat revascularization associated with DES appears to be limited to patients who present with stable angina pectoris. This observation may reflect the more frequent presence of vulnerable plaques in patients with ACS.