Cost-Effectiveness of TransCarotid Artery Revascularization versus Carotid Endarterectomy

OBJECTIVES

Recent studies have demonstrated that TransCarotid Artery Stenting (TCAR) has comparable outcomes to the surgical gold standard, carotid endarterectomy (CEA). However, few studies have analyzed the cost of TCAR and no study has evaluated its cost-effectiveness. The purpose of this study is to conduct a cost-effectiveness analysis comparing TCAR to CEA for carotid artery stenosis.

METHODS

We built a Markov microsimulation using transition probabilities and utilities from existing literature for symptomatic patients undergoing TCAR or CEA. Costs were derived from literature then converted to 2019 dollars. The model included six health states with monthly cycle lengths: surgery, death, alive after surgery, alive after myocardial infarction, alive after stroke, and alive after stroke and death. Quality adjusted life years (QALYs), costs, and incremental cost-effectiveness ratio (ICER) were analyzed over a five-year period. One-way sensitivity and probabilistic sensitivity analyses were conducted to study the impact of parameter variability on cost effectiveness.

RESULTS

For symptomatic patients, CEA cost $7821 for 2.85 QALYs while TCAR cost $19154 for 2. 92 QALYs, leading to an ICER of $152,229 per QALY gained in the TCAR arm Sensitivity analysis demonstrated that our model was most sensitive to probability of restenosis, costs of TCAR and costs of CEA. Probabilistic sensitivity analysis demonstrated TCAR would be considered cost effective 49% of iterations.

CONCLUSIONS

This study found that while five-year costs for TCAR were greater than CEA, TCAR afforded greater QALYs than CEA. TCAR became cost-effective at six-years follow-up.

Cost-utility analysis of stenting versus endarterectomy in the International Carotid Stenting Study

BACKGROUND

The International Carotid Stenting Study was a multicenter randomized trial in which patients with symptomatic carotid artery stenosis were randomly allocated to treatment by carotid stenting or endarterectomy. Economic evidence comparing these treatments is limited and inconsistent.

AIMS

We compared the cost-effectiveness of stenting versus endarterectomy using International Carotid Stenting Study data.

METHODS

We performed a cost-utility analysis estimating mean costs and quality-adjusted life years per patient for both treatments over a five-year time horizon based on resource use data and utility values collected in the trial. Costs of managing stroke events were estimated using individual patient data from a UK population-based study (Oxford Vascular Study).

RESULTS

Mean costs per patient (95% CI) were US$10,477 ($9669 to $11,285) in the stenting group (N = 853) and $9669 ($8835 to $10,504) in the endarterectomy group (N = 857). There were no differences in mean quality-adjusted life years per patient (3.247 (3.160 to 3.333) and 3.228 (3.150 to 3.306), respectively). There were no differences in adjusted costs between groups (mean incremental costs for stenting versus endarterectomy $736 (95% CI -$353 to $1826)) or adjusted outcomes (mean quality-adjusted life years gained -0.010 (95% CI -0.117 to 0.097)). The incremental net monetary benefit for stenting versus endarterectomy was not significantly different from zero at the maximum willingness to pay for a quality-adjusted life year commonly used in the UK. Sensitivity analyses showed little uncertainty in these findings.

CONCLUSIONS

Economic considerations should not affect whether patients with symptomatic carotid stenosis undergo stenting or endarterectomy.

Clinical Practice Variation Needs to be Considered in Cost-Effectiveness Analyses: A Case Study of Patients with a Recent Transient Ischemic Attack or Minor Ischemic Stroke

BACKGROUND AND OBJECTIVE

The cost-effectiveness of clinical interventions is often assessed using current care as the comparator, with national guidelines as a proxy. However, this comparison is inadequate when clinical practice differs from guidelines, or when clinical practice differs between hospitals. We examined the degree of variation in the way patients with a recent transient ischemic attack (TIA) or minor ischemic stroke are assessed and used the results to illustrate the importance of investigating possible clinical practice variation, and the need to perform hospital-level cost-effectiveness analyses (CEAs) when variation exists.

METHODS

Semi-structured interviews were conducted with 16 vascular neurologists in hospitals throughout the Netherlands. Questions were asked about the use of initial and confirmatory diagnostic imaging tests to assess carotid stenosis in patients with a recent TIA or minor ischemic stroke, criteria to perform confirmatory tests, and criteria for treatment. We also performed hospital-level CEAs to illustrate the consequences of the observed diagnostic strategies in which the diagnostic test costs, sensitivity and specified were varied according to the local hospital conditions.

RESULTS

56 % (9/16) of the emergency units and 63 % (10/16) of the outpatient clinics use the initial and confirmatory diagnostic tests to assess carotid stenosis in accordance with the national guidelines. Of the hospitals studied, only one uses the recommended criteria for use of a confirmatory test, 38 % (6/16) follow the guidelines for treatment. The most cost-effective diagnostic test strategy differs between hospitals.

CONCLUSIONS

If important practice variation exists, hospital-level CEAs should be performed. These CEAs should include an assessment of the feasibility and costs of switching to a different strategy.

[Cost Comparison of Carotid Endarterectomy versus Carotid Stenting in Japan]

Carotid artery stenting (CAS) has been covered by the health insurance system in Japan since 2008. There have been few studies concerning medical costs and charges for patients who received CEA or CAS in Japan. The aim of this study was to elucidate the difference in the costs between the patients who received CEA and those who received CAS in Japan. Between 2010 and 2011, 19 patients who received CEA and 20 patients who received CAS were retrospectively reviewed. Age, sex, symptomatic/asymptomatic, emergent/scheduled, length of stay, outcome, cost for the procedure (professional fee), supply for the operation, the total medical service fee, and copayment of the patients was compared between the two treatment groups. No significant difference was detected between the two groups except for the supply of the operation and the total medical service fee (CEA:mean 1,565,580 yen vs CAS 2,758,360 yen, p=0.0001). On the other hand, no significant difference was obtained in the copayment of the patients (CEA 71,895 yen, CAS 72,458 yen). Even when limited to the scheduled cases, similar results were obtained. There is a monthly copayment limit in the health insurance system in Japan, which results in a reasonable charge for patients who received CAS, despite the fact that the rest of the fee including high costs for the supplies was paid by the company and the nation. To reduce the medical costs, Japanese have to be aware of the high costs in CAS, most of which is due to the supplies.

Hospital resource use following carotid endarterectomy in 2006: analysis of the nationwide inpatient sample

To explore the relationships among patient age and length of stay (LOS), hospital costs, and discharge disposition following carotid endarterectomy (CEA), we identified discharge records from the 2006 Nationwide Inpatient Sample (NIS). The primary outcome was LOS from the surgical procedure to discharge. We examined LOS from procedure to discharge because the time from procedure to discharge may better reflect hospital stay due to the procedure itself for subjects with symptomatic carotid artery disease compared with the inclusion of days hospitalized for stroke recovery. Secondary endpoints included total LOS, discharge disposition, and cost of hospitalization. More than 90% of the 118,218 discharge records for CEA examined were for patients with asymptomatic carotid disease. The LOS from procedure to discharge and total LOS increased per decade, starting at age 70-79 years. Age per decade increased the likelihood of needed an LOS from procedure to discharge of >1 day. The same trend was seen for the likelihood of needing a >2-day postoperative stay; patients age ≥80 years required the longest postoperative LOS (odds ratio [OR]=1.45 for >1 day and 1.45 for >2 days; both P<.001). Total hospital costs averaged $10,965 for all discharges. For age dichotomized at 80 years, the average cost increased by $845. Age≥80 years also was independently associated with discharge to a skilled nursing facility (SNF) (OR=2.4; 95% confidence interval=2.09-2.76). Hospital LOS and costs following CEA increased with increasing patient age. Morbidity after CEA should be discussed with patients in whom revascularization for asymptomatic disease is being considered.

The Carotid Revascularization Endarterectomy vs. Stenting Trial completes randomization: lessons learned and anticipated results

The Carotid Revascularization Endarterectomy vs. Stenting Trial (CREST) completed randomization on July 18, 2008. Sponsored by the National Institute of Neurological Disorders and Stroke (NINDS), the trial has enrolled 2,522 participants across North America and is the largest randomized clinical trial (RCT) comparing the efficacy of carotid artery stenting (CAS) to carotid endarterectomy (CEA). It is also the largest RCT to assess carotid revascularization in both symptomatic and asymptomatic patients with carotid artery stenosis. Conventional-risk patients with symptomatic carotid stenosis (> or =50% by angiography, > or =70% by ultrasound) or asymptomatic carotid stenosis (> or =60% by angiography, > or =70% by ultrasound) were randomized to both treatment arms in a 1:1 ratio. Eligibility criteria for CREST were similar to those of the previous NINDS-sponsored CEA RCTs. The investigational devices used in the CAS arm of the study are the RX Acculink stent and the RX Accunet embolic protection system, (Abbott Vascular, Santa Clara, Calif). The primary aim is to contrast the efficacy of CAS versus CEA in preventing stroke, myocardial infarction, and all-cause mortality during a 30-day peri-procedural period, and ipsilateral stroke over the follow-up period (extending up to four years). The secondary aims are to contrast the efficacy of CAS and CEA in men and women, the restenosis rates of the two procedures, health-related quality of life, and cost effectiveness of CAS and CEA. The conclusion of enrollment in CREST marks the end of a long recruitment period from 117 community and academic hospital centers across the United States and Canada. Each surgeon and interventionalist underwent a rigorous credentialing process that included performance-assessment of prior CEA and CAS procedures. Credentialing of interventionalists also included a review of additional CAS procedures enrolled into a CREST lead-in phase prior to entering patients into the randomized trial; 1564 patients were enrolled in the lead-in, the final pathway for the largest credentialing effort to date for any clinical trial. CREST will provide long-term follow-up after carotid revascularization based on systematic ultrasonographic and neurologic surveillance, and on quality of life and cost-effectiveness comparisons between CAS and CEA in the setting of a RCT. We present a brief description of the CREST protocol, impediments that were overcome during the trial, salient results from the lead-in phase of the trial, a summary of enrollment activities and characteristics of the final cohort, and a timeline for anticipated results from the randomized phase.

Carotid atherosclerosis and cardiovascular risk stratification: Role and cost‐effectiveness of echo‐Doppler examination in untreated essential hypertensives

OBJECTIVE

To investigate the impact and cost-effectiveness of carotid ultrasonographic examination on total risk stratification in low-medium risk hypertensive patients in relation to age (< 50 and > 50 years) and gender.

METHODS

Five hundred and eighty untreated hypertensives classified at low-medium risk, after the routine work-up recommended by the 2003 ESH/ ESC guidelines, were included in the study and total risk was reassessed by adding the results of carotid ultrasonography.

RESULTS

According to the stratification based on routine work-up 16.3% of the whole population was considered at low added risk and 83.7% at medium added risk. Carotid subclinical damage was found in 158 patients (27.0%), who were then reclassified in the high-risk stratum. Prevalence rates of patients reclassified in the high-risk stratum as a consequence of carotid damage were as follows: 12.6% in men < 50 years, 14.1% in women < 50 years, 53.0% in men > or = 50 years and 40.1% in women > or = 50 years. The cost per detected case of carotid atherosclerosis was 473 euro in patients < 50 years and 133 euro in those > or = 50 years.

CONCLUSIONS

Our results show that: (i) the use of carotid ultrasonography allows a much more accurate identification of high-risk individuals; (ii) its impact and cost-effectiveness on the risk stratification process differs markedly according to the age and gender; (iii) the selective use of this procedure in subjects at high risk of target organ damage may substantially improve the cost of primary prevention.

Economic Evaluation of Carotid Artery Stenting Versus Carotid Endarterectomy for the Treatment of Carotid Artery Stenosis

BACKGROUND

The clinical effectiveness of carotid endarterectomy (CEA) is well established. But the economic impact of CEA and carotid artery stenting (CAS) is still uncertain. The objective of this study was to compare hospital costs and reimbursement for CAS and CEA.

STUDY DESIGN

We performed a retrospective database analysis on pair-matched patients who underwent CEA (n = 31) and CAS (n = 31) at the Richard M Ross Heart Hospital in Columbus, OH. The hospital's clinical and financial databases were used to obtain patient-specific information and procedural charges. Cost data were generated by applying the hospital's ratio of cost to charges for all DRG charges. The Wilcoxon signed-rank test was used to examine the differences between costs of these procedures.

RESULTS

Data are reported as mean +/- SD. The mean age of patients in CAS group was 70.14 years (+/- 1.60 years) versus 68.64 years (+/- 1.75 years) for CEA patients (p < 0.05). The total direct cost associated with CEA ($3,765.12+/-$2,170.82) was significantly lower than the CAS cost ($8,219.71+/-$2,958.55, p < 0.001). The mean procedural cost for CAS ($7,543.61+/-$2,886.54) was significantly higher than that for CEA ($2,720.00+/-$926.38, p < 0.001). The hospital experienced cost savings of $9,690.87 for CEA versus $4,804.79 for CAS from private insurance. Similarly, savings obtained by Medicare-enrolled CEA patients were higher than those for CAS patients ($1,497.79).

CONCLUSIONS

CAS is significantly more expensive than CEA, with a major portion of cost attributed to the total procedural cost. The hospital experienced significant savings from CEA procedures compared with CAS under all DRG classifications and insurers. Hospitals must develop new financial strategies and improve the efficiency of infrastructure to make CAS financially viable.

[Carotid surgery in regional anesthesia--anesthesiological, neurological and surgical aspects]

Surgery of the carotid artery is justified only if it is performed with low complication rates. The essential advantages of regional anesthesia in comparison to general anesthesia are a secure neuromonitoring, hemodynamic stability and prolonged analgesia. Regional anesthesia for carotid surgery, which is described methodically in this paper, needs only a minor expenditure. Our own data show that patients with a contralateral occlusion of the internal carotid artery and patients with a high risk for surgery (ASA IV) are at a high risk for neurological events during carotid crossclamping. Consequences of regional anesthesia on the surgical procedure are to ignore. The question, whether economic advantages exist for regional anesthesia, cannot yet be answered.

Population-Based Study of Determinants of Initial Secondary Care Costs of Acute Stroke in the United Kingdom

BACKGROUND AND PURPOSE

To determine the cost-effectiveness of specific interventions to prevent or treat acute stroke, it is necessary to know the costs of stroke according to patient characteristics and stroke subtype and etiology. However, very few such data are available and none from population-based studies. We determined the predictors of resource use and acute care costs of stroke using data from a population-based study.

METHODS

Data were obtained from the Oxford Vascular study, a population-based cohort of all individuals in nine general practices in Oxfordshire, UK, which identified 346 patients with a first or recurrent stroke during April 1, 2002, to March 31, 2004. Univariate and multivariate analyses were performed to identify the main predictors of resource use and costs.

RESULTS

Acute care costs ranged from 326 pounds sterling (lower decile) to 19,901 pounds sterling (upper decile). There were multiple important univariate interrelations of patient characteristics, stroke subtype, and stroke etiology with hospital admission, length of stay, and 30-day case-fatality. For example, patients with primary intracerebral hemorrhage were more likely to be admitted than patients with partial anterior circulation ischemic stroke and less likely to survive without disability, but length of stay was reduced as a result of high early case-fatality such that cost was substantially less. However, the majority of univariate predictors of resource use, cost, and outcome were confounded by initial stroke severity as measured by the National Institutes of Health Stroke Scale score, which accounted for approximately half of the predicted variance in cost. Cost increased approximately linearly up to an National Institutes of Health Stroke Scale score of 18 and then fell steeply at higher scores as a result of rising early case-fatality.

CONCLUSIONS

Several patient and event-related characteristics explained the wide range of initial secondary care costs of acute stroke, but stroke severity was by far the most important independent predictor.

Current status of carotid artery stenting

This Clinical Update summarizes the results of larger case series, industry-sponsored registries, and randomized trials of carotid artery stenting (CAS). In >20 case series that studied >24,000 patients undergoing CAS, 51% of patients were symptomatic, most procedures (97%) resulted in successful stent deployment, and 30-day stroke rates varied from 1% to 8%, with a trend toward lower rates as experience and embolic protection device (EPD) use increased. In 12 industry-sponsored registries (none were published in peer-reviewed journals), 30-day stroke rates varied from 2% to 7%, and 30-day combined adverse events, including stroke, death, and myocardial infarction, were 3% to 9%. More than 12 randomized trials comparing CAS and carotid endarterectomy (CEA) have been initiated since 1998. Results have varied over time, depending on the population studied and the technology used. However, the largest and most recent results of the completed SAPPHIRE trial in high-risk patients undergoing CAS with the use of EPDs demonstrated that CAS is at least not inferior to CEA, with a 1-year combined adverse event rate of 12% for CAS and 20% for CEA (P = .05). Other ongoing trials will address not only whether CAS could be superior to CEA in high-risk patients but also, more importantly, whether CAS is beneficial in other subgroups, such as low-risk and asymptomatic patients.

Cost-effectiveness of diagnostic strategies prior to carotid endarterectomy

The main objective of this study was to assess the long-term cost-effectiveness of five alternative diagnostic strategies for identification of severe carotid stenosis in recently symptomatic patients. A decision-analytical model with Markov transition states was constructed. Data sources included a prospective study involving 167 patients who had screening Doppler ultrasound (DUS), confirmatory contrast-enhanced magnetic resonance angiography (CEMRA) and confirmatory digital subtraction angiography (DSA), individual patient data from the European Carotid Surgery Trial and other published clinical and cost data. A "selective" strategy, whereby all patients receive DUS and CEMRA (only proceeding to DSA if the CEMRA is positive and the DUS is negative), was most cost-effective. This was both the cheapest imaging and treatment strategy (35,205 dollars per patient) and yielded 6.1590 quality-adjusted life years (QALYs), higher than three alternative imaging strategies. Probabilistic sensitivity analysis demonstrated that there was less than a 10% probability that imaging with either DUS or DSA alone are cost-effective at the conventional 50,000 dollars/QALY threshold. In conclusion, DSA is not cost-effective in the routine diagnostic workup of most patients. DUS, with additional imaging in the form of CEMRA, is recommended, with a strategy of "CEMRA and selective DUS review" being shown to be the optimal imaging strategy.

Carotid endarterectomy: update on the gold standard treatment for carotid stenosis

Many prospective, randomized clinical trials evaluating the safety and efficacy of carotid endarterectomy (CEA) versus medical management in the prevention of ischemic stroke were performed in the 1990s. Clinical trials are underway that will compare CEA outcomes to carotid stenting; however, relatively few studies have examined the outcomes of modern CEA. The purpose of this report is to examine current outcomes of CEA and evaluate hospital costs and length of stay. Statewide results were collected for all hospitals, except Veterans Administration hospitals, by Virginia Health Information (VHI). Data for the years 1997-2001 were evaluated, and data were based on the All Patient Refined Diagnostic Related Group (APR-DRG; 3M Company). A total of 14,095 CEAs were performed in a 5-year period. The mortality of patients undergoing CEA was 0.5 per cent. The stroke rate was 1 per cent overall and decreased each year of the study. Mean and median lengths of hospital stay were 3 and 2 days, respectively. Length of stay decreased over the course of this study. Mean and median hospital costs were 14,331 dollars and 11,268 dollars. Higher rates of mortality and stroke and higher costs were observed at low-volume hospitals. The need for CEA is substantial. CEA is safe and inexpensive. The data presented here demonstrates continued refinement in CEA, leading to a very low rate of perioperative adverse events, declining lengths of stay, and low hospital costs.

Cost of treating high-risk symptomatic carotid artery stenosis: stent insertion and angioplasty compared with endarterectomy

Object. Definitive data characterizing the safety and efficacy of carotid angioplasty with stent placement (CAS) for symptomatic, occlusive carotid artery (CA) disease require further refinements and standardization of techniques as well as large prospective studies on a par with the North American Symptomatic Carotid Endarterectomy Trial (NASCET). Despite the absence of such data, many surgeons have performed angioplasty and stent placement in patients with clinical or anatomical features known to add significant perioperative risk and capable of disqualifying the patients from participation in NASCET. There exists no cost analysis comparing high-risk endarterectomy with percutaneous angioplasty and stent insertion.

Methods. Forty-five patients (29 men and 16 women) with high-risk, symptomatic CA stenosis have been treated with CAS at the authors' institution since 1996. Indications for this procedure included symptomatic recurrent stenosis following CA endarterectomy (CEA), active coronary disease, high CA bifurcation, and severe medical comorbidities. A long-standing CEA computer database was screened for control patients with similar risk factors; 391 patients (276 men and 115 women) were identified. Actual cost data, duration of hospital stay, and relevant clinical data from the time of treatment until hospital discharge were collected in each patient. The median total cost of CAS was $10,628, whereas that for CEA was $10,148 (p = 0.495).

Conclusions. In patients with high-risk, NASCET-ineligible CA stenosis there was no overall statistically significant cost difference between CEA and CAS. Given that there may not be a cost advantage for either procedure, procedural risk, efficacy, and durability should be key factors in determining the optimal treatment strategy.

Imaging of Carotid Arteries in Symptomatic Patients: Cost-effectiveness of Diagnostic Strategies

PURPOSE

To assess the cost-effectiveness of noninvasive imaging strategies in patients who have had a transient ischemic attack (TIA) or minor stroke and are suspected of having significant carotid artery stenosis.

MATERIALS AND METHODS

From 1997 through 2000, 350 patients were included in a multicenter blinded consecutive cohort study. The sensitivities and specificities of duplex ultrasonography (US), magnetic resonance (MR) angiography, and these two examinations combined were estimated by using digital subtraction angiography (DSA) as the reference standard. The actual costs (from a societal perspective) of performing imaging and endarterectomy were estimated. The survival, quality of life, and costs associated with stroke were based on data reported in the literature. Markov modeling was used to predict long-term outcomes. Subsequently, a decision model was used to calculate costs, quality-adjusted life-years (QALYs), and incremental costs per QALY gained for 62 examination-treatment strategies. Extensive sensitivity analyses were performed.

RESULTS

Duplex US had 88% sensitivity and 76% specificity with use of conventional cutoff criteria. MR angiography had comparable values: 92% sensitivity and 76% specificity. Combined concordant duplex US and MR angiography had superior diagnostic performance: 96% sensitivity and 80% specificity. Duplex US alone was the most efficient strategy. Adding MR angiography led to a marginal increase in QALYs gained but at prohibitive costs (cost-effectiveness ratio > 1 500 000 per QALY gained). Performing DSA owing to discordant duplex US and MR angiographic findings and to confirm duplex US and MR angiographic findings led to extra costs and QALY loss owing to complications. Sensitivity analyses revealed that duplex US as a stand-alone examination remained the preferred strategy while estimates and assumptions were varied across plausible ranges.

CONCLUSION

Duplex US performed without additional imaging is cost-effective in the selection of symptomatic patients suitable for endarterectomy. Adding MR angiography increases effectiveness slightly at disproportionately high costs, whereas DSA is inferior because of associated complications.

Focused screening for occult carotid artery disease: patients with known heart disease are at high risk

OBJECTIVES

Stroke puts a major financial burden on our healthcare system. However, carotid duplex scanning performed as a screening test for occult carotid artery stenosis (CAS) currently is not reimbursed by Medicare. The goals of this study were to develop a cost-effective stroke screening program, to determine the prevalence of potential causes of stroke in this population, and to define a population at high risk in which screening would be most effective.

METHODS

In a community-based stroke screening program, patients were eligible if they were older than 60 years and had a history of either hypertension, heart disease, or cigarette smoking, or a family history of stroke. Screening included blood pressure determination, an electrocardiographic rhythm strip, and a previously validated modified carotid duplex ultrasound examination to detect CAS 50% or greater. The relationships between standard demographic risk factors and screening outcomes were analyzed.

RESULTS

Screening was performed in 610 patients. Unilateral or bilateral CAS was detected in 66 patients (10.8%). The finding of occult CAS was more prevalent than that of new hypertension (2.6%) or new atrial fibrillation (0.5%). Patients with known hypertension were significantly more likely to have CAS than were those without hypertension (12.7% vs 7.8%; P =.05). Patients with heart disease were significantly more likely to have CAS than were those without heart disease (18.2% vs 8%; P <.0001). Patients with both risk factors were significantly more likely to have occult carotid artery disease than were patients without either risk factor (22.1% vs 8.5%; P <.0001). Multivariate analysis with logistic regression revealed a history of heart disease as an independent predictor of occult carotid artery disease (odds ratio 95% confidence interval, 1.4-4.4). Type of heart disease was not a significant factor in predicting occult CAS. Direct cost of the screening, including community outreach, nurses, technicians, support staff, and miscellaneous expenses, was less than $75 per patient.

CONCLUSIONS

In a screening program for treatable causes of potential stroke, CAS was the most commonly diagnosed disease. More than one of every five patients with known hypertension and heart disease had occult CAS. Known heart disease of any type was a significant independent predictor of occult CAS. Screening for treatable causes of potential stroke can be cost-effective. This information could help to further target populations to screen for occult CAS and to justify reimbursement for screening carotid duplex scanning examinations.

Is carotid angioplasty and stenting more cost effective than carotid endarterectomy?

OBJECTIVE

Carotid angioplasty and stenting (CAS) has been advocated as a minimally invasive and inexpensive alternative to carotid endarterectomy (CEA). However, a precise comparative analysis of the immediate and long-term costs associated with these two procedures has not been performed. To accomplish this, a Markov decision analysis model was created to evaluate the relative cost effectiveness of these two interventions.

METHODS

Procedural morbidity/mortality rate for CEA and costs (not charges) were derived from a retrospective review of consecutive patients treated at New York Presbyterian Hospital/Cornell (n = 447). Data for CAS were obtained from the literature. We incorporated into this model both the immediate procedural costs and the long-term cost of morbidities, such as stroke (major stroke in the first year = $52,019; in subsequent years = $27,336/y; minor stroke = $9419). We determined long-term survival rate in quality-adjusted life years and lifetime costs for a hypothetic cohort of 70-year-old patients undergoing either CEA or CAS. Our measure of outcome was the cost-effectiveness ratio.

RESULTS

The immediate procedural costs of CEA and CAS were $7871 and $10,133 respectively. We assumed major plus minor stroke rates for CEA and CAS of 0.9% and 5%, respectively. We assumed a 30-day mortality rate of 0% for CEA and 1.2% for CAS. In our base case analysis, CEA was cost saving (lifetime savings = $7017/patient; increase in quality-adjusted life years saved = 0.16). Sensitivity analysis revealed major stroke and death rates as the major contributors to this differential in cost effectiveness. Procedural costs were less important, and minor stroke rates were least important. CAS became cost effective only if its major stroke and mortality rates were made equivalent to those of CEA.

CONCLUSION

CEA is cost saving compared with CAS. This is related to the higher rate of stroke with CAS and the high cost of stents and protection devices. To be economically competitive, the mortality and major stroke rates of CAS must be at least equivalent if not less than those of CEA.

[First experiences with clinical pathways in carotid surgery]

The introduction of guidelines for carotid surgery into praxis. Early experiences with the clinical pathway. With the use of DRG's for reimbursements, a new organization of clinical pathways may play an increasingly important role in the delivery of health care. The impact of clinical pathways as a management tool in the treatment of patients with carotid occlusive disease was studied. Representatives of all involved disciplines identified in which sequence, where, when, by whom and which care a patient with carotid disease should receive. The individual steps of care were analysed, estimating their utility and determining a new plan for a patient's care. The clinical pathway specifies a target time window, defining exactly the internal and external logistics. The early experiences demonstrate that clinical pathways can be a useful tool for improving the quality of health care by improving cost and process transparency. Hospital length of stay was reduced by 2.3 days.

Factors predicting prolonged length of stay after carotid endarterectomy

BACKGROUND

Over the last several years, implementation of critical pathways in patients undergoing carotid endarterectomy has decreased postoperative length of stay significantly. Discharge the day after surgery has become commonplace in many centers, including our own. Unfortunately, managed care may interpret this refinement as a standard of care and limit reimbursement or even disallow admissions extending beyond 1 day. We therefore examined our carotid registry to identify risk factors associated with postoperative length of stay exceeding 1 day.

METHODS

We retrospectively reviewed all patients undergoing carotid endarterectomy at our academic center from May 1996 through April 1999. Combined procedures and patients undergoing subsequent noncarotid-related procedures on those admissions were excluded. The charts were inspected for atherosclerosis risk factors, including sex and age, specific attending surgeon, side of the surgery, use of intravenous vasoactive drugs, actual preoperative blood pressure, and presence of neurologic symptoms or postoperative complications. Multiple regression analysis was performed on all collected variables. Statistical significance was inferred for P less than.05.

RESULTS

A total of 188 patients met the study criteria and had complete, retrievable medical records. A mean postoperative length of stay of 1.65 +/- 0.08 days and a mean total length of stay of 2.17 +/- 0.14 days were observed. Fifty-seven percent of patients went home the day after surgery. There was a 1.6% stroke-mortality rate. Significant predictors of a prolonged stay, listed in order of decreasing importance on the basis of their calculated contribution to prolonging the postoperative length of stay, are as follows (P value; beta coefficient): postoperative complications (<.0001; 1.03), age > 79 years (.008; 0.547), diabetes mellitus (.011; 0.407), female sex (.007; 0.398), and intravenous vasodilator requirement (. 035; 0.382). Other atherosclerosis risk factors, prior neurologic symptoms, the postoperative use of vasopressors, and reoperative surgery did not contribute to extended length of stay.

CONCLUSIONS

Discharge on the first postoperative day is feasible in many, but not all, patients undergoing carotid endarterectomy. Our data help define subsets of patients at risk for prolonged postoperative stay. Targeting these subsets for preoperative medical and social interventions may allow safe early discharge more frequently.

Power Doppler imaging: initial evaluation as a screening examination for carotid artery stenosis

PURPOSE

To evaluate power Doppler imaging as a possible screening examination for carotid artery stenosis.

MATERIALS AND METHODS

In the principal pilot study, a prospective, blinded comparison of power Doppler imaging with duplex Doppler imaging, the reference-standard method, was conducted in 100 consecutive patients routinely referred for carotid artery imaging at a large, private multispecialty clinic. In the validation pilot study, a prospective, blinded comparison of power Doppler imaging with digital subtraction angiography, the reference-standard method, was conducted in 20 consecutive patients routinely referred at a teaching hospital. Using conservative assumptions, the authors performed cost-effectiveness analysis.

RESULTS

Power Doppler imaging produced diagnostic-quality images in 89% of patients. When the images of the patients with nondiagnostic examinations were regarded as positive, power Doppler imaging had an area under the receiver operating characteristic curve, A(z), of 0.87, sensitivity of 70%, and specificity of 91%. The validation study results were very similar. The cost-effectiveness of screening and, as indicated, duplex Doppler imaging as the definitive diagnostic examination and endarterectomy was $47,000 per quality-adjusted life-year.

CONCLUSION

The A(z) value for power Doppler imaging compares well with that for mammography, a generally accepted screening examination, and with most other imaging examinations. Power Doppler imaging is likely to be a reasonably accurate and cost-effective screening examination for carotid artery stenosis in asymptomatic populations.

Cost-effectiveness analysis of therapy for symptomatic carotid occlusion: PET screening before selective extracranial-to-intracranial bypass versus medical treatment

The St. Louis Carotid Occlusion Study (STLCOS) demonstrated that increased cerebral oxygen extraction fraction (OEF) detected by PET scanning predicted stroke in patients with symptomatic carotid occlusion. Consequently, a trial of extracranial-to-intracranial (EC/IC) arterial bypass for these patients was proposed. The purpose of this study was to examine the cost-effectiveness of using PET in identifying candidates for EC/IC bypass.

METHODS

A Markov model was created to estimate the cost-effectiveness of PET screening and treating a cohort of 45 symptomatic patients with carotid occlusion. The primary outcome was incremental cost for PET screening and EC/IC bypass (if OEF was elevated) per incremental quality-adjusted life year (QALY) saved. Rates of stroke and death with surgical and medical treatment were obtained from EC/IC Bypass Trial and STLCOS data. Costs were estimated from the literature. Sensitivity analyses were performed for all assumed variables, including the PET OEF threshold used to select patients for surgery.

RESULTS

In the base case, PET screening of the cohort followed by EC/IC bypass on 36 of the 45 patients yielded 23.2 additional QALYs at a cost of $20,000 per QALY, compared with medical therapy alone. A more specific PET threshold, which identified 18 surgical candidates, gained 22.6 QALYs at less cost than medical therapy alone. The results were sensitive to the perioperative stroke rate and the stroke risk reduction conferred by EC/IC bypass surgery.

CONCLUSION

If postoperative stroke rates are similar to stroke rates observed in the EC/IC Bypass Trial, EC/IC bypass will be cost-effective in patients with symptomatic carotid occlusion who have increased OEF. A clinical trial of medical therapy versus PET followed by EC/IC bypass (if OEF is elevated) is warranted.

Attitudes of Canadian and U.S. neurologists regarding carotid endarterectomy for asymptomatic stenosis

BACKGROUND

The American Heart Association carotid endarterectomy (CE) guidelines endorse CE for asymptomatic carotid stenosis if the procedure can be performed with low morbidity. However, the Canadian Stroke Consortium has published a consensus against CE for asymptomatic stenosis. The views of practicing neurologists in the two countries on this subject are unclear.

METHODS

A survey was undertaken of 270 neurologists from either Florida or Indiana and 180 neurologists from either Ontario or Quebec.

RESULTS

The survey was returned by 36% of neurologists. Both Florida (65%) and Indiana neurologists (35%) were significantly more likely than Canadian neurologists (11%) to sometimes/often refer patients for surgery(p<0.001). Neurologists from Florida relied more on noninvasive methods of carotid stenosis assessment (36%) than Canadian neurologists (12%, p=0.003), who preferred angiography. Neurologists from Florida more often cited medicolegal concerns as a reason for referring patients for surgery (27%), compared to Canadian neurologists (3%, p=0.0001).

CONCLUSIONS

Practices pertaining to carotid stenosis evaluation and management differ both regionally and by country. Canadian neurologists refer fewer asymptomatic patients for CE and rely more on angiography as a preoperative diagnostic tool. The potential of medicolegal liability is a greater force in clinical decision-making for certain U.S. neurologists, compared to their Canadian counterparts. These differences may partly explain the variations in CE utilization in the two countries.

Estimating the contemporary in-hospital costs of carotid endarterectomy

Carotid endarterectomy (CEA) is the treatment of choice for symptomatic carotid stenosis and selective asymptomatic lesions. Alternative approaches have recently been championed under the guise of increased efficacy and decreased cost. The purpose of this study was to determine the results and in-hospital costs of CEA in a university hospital in the modern era. A retrospective chart review was undertaken for all patients undergoing CEA between January 1995 and December 1997. This corresponded to the implementation of a clinical path and extended efforts toward cost reduction. Patients undergoing combined CEA and cardiopulmonary bypass were excluded (n = 3). Cost was analyzed by the hospital Office of Program Planning using TSI (Transition Systems, Inc.) software. Direct costs are related to the utilization of clinical resources and are therefore manageable by clinicians (bed, room, supplies, nursing staff, OR staff, radiology, pharmacy, etc.). Total costs additionally include administration and overhead costs not directly chargeable to patient accounts. The results of this study showed that CEA can be safely performed with brief hospital stays and reasonable hospital costs. Results of alternative interventions for the treatment of carotid stenosis should be compared to these contemporary data.

Is carotid endarterectomy cost-effective in symptomatic patients with moderate (50% to 69%) stenosis?

OBJECTIVE

Recently published data from the North American Carotid Endarterectomy Trial revealed a benefit for carotid endarterectomy (CEA) in symptomatic patients with moderate (50% to 69%) carotid stenosis. This benefit was significant but small (absolute stroke risk reduction at 5 years, 6.5%; 22.2% vs 15.7%), and thus, the authors of this study were tentative in the recommendation of operation for these patients. To better elucidate whether CEA in symptomatic patients with moderate carotid stenosis is a proper allocation of societal resources, we examined the cost-effectiveness of this intervention.

METHODS

A decision-analytic Markov process model was constructed to determine the cost-effectiveness of CEA versus medical treatment for a hypothetical cohort of 66-year-old patients with moderate carotid stenosis. This model allowed the comparison of not only the immediate hospitalization but also the lifetime costs and benefits of these two strategies. Our measure of outcome was the cost-effectiveness ratio (CER), defined as the incremental lifetime cost per quality-adjusted life year saved. We assumed an operative stroke and death rate of 6.6% and a declining risk of ipsilateral stroke after the ischemic event with medical treatment (first year, 9.3%; second year, 4%; subsequent years, 3%). The hospitalization cost of CEA ($6,420) and the annual costs of major stroke ($26,880), minor stroke ($798), and aspirin therapy ($63) were estimated from a hospital cost accounting system and the literature.

RESULTS

CEA for moderate carotid stenosis increased the survival rate by 0.13 quality-adjusted life years as compared with medical treatment at an additional lifetime cost of $580. Thus, CEA was cost-effective with a CER of $4,462. Society is usually willing to pay for interventions with CERs of less than $60,000 (eg, CERs for coronary artery bypass grafting at $9,100 and for dialysis at $53,000). CEA was not cost-effective if the perioperative risk was greater than 11.3%, if the ipsilateral stroke rate associated with medical treatment at 1 year was reduced to 4.3%, if the age of the patient exceeded 83 years, or if the cost of CEA exceeded $13,200.

CONCLUSION

CEA in patients with symptomatic moderate carotid stenosis of 50% to 69% is cost-effective. Perioperative risk of stroke or death, medical and surgical stroke risk, cost of CEA, and age are important determinants of the cost-effectiveness of this intervention.

Unplugging the mystery of carotid endarterectomy patient care

The first two goals of health care must always be quality care and achievement of patient outcomes. In today's health care environment, these goals are achieved with an eye on the financial picture. Cost-saving efforts by decreasing LOS, decreasing the use of ICUs, and lowering laboratory and radiologic expenses without affecting the quality of care are requirements in today's setting. The process of creating a clinical pathway for patients undergoing CEA can help to examine your care and determine evidence-based practice.

Carotid endarterectomy: changing practice patterns

BACKGROUND

Cost-effective carotid endarterectomy implies a good outcome; low morbidity, a short hospital stay and selective use of non-invasive preoperative diagnostic tests done alone.

METHODS

A solo surgeon's clinical experience with two hundred and eighteen consecutive operations, over seven years, at two Community Hospitals in Northern Virginia.

RESULTS

There were three perioperative strokes, of which one resulted in death, for a mortality rate of 0.45%, and a stroke rate of 1.4%. The majority of the operations in the past two years were done on the basis of Duplex ultrasonography and magnetic resonance angiography, but without invasive angiography. General anesthesia, routine use of shunt and use of autogenous vein patch in almost every case was employed. Patients were selectively observed in the Intensive Care Unit postoperatively. Forty eight percent of the series and 75% of the most recent 121 patients operated on in 1995 and 1996 were discharged on the first postoperative day without any need for re-admission to the hospital.

CONCLUSIONS

Carotid endarterectomy can be performed with a short hospital stay and an extremely low morbidity and mortality. Carotid endarterectomy is a highly effective surgical procedure both from the medical and economy stand-points.

A new accurate, rapid and cost-effective protocol for stroke-prevention screening

The three immediate causes of stroke are cervical carotid artery disease, atrial fibrillation and hypertension. Recognition and appropriate management of these causes can prevent the majority of strokes they would have caused. The purpose of this study was to develop a new protocol for screening for these causes that is more accurate, rapid and cost effective than existing protocols. In this protocol, rather than relying on auscultation with a stethoscope, the carotid artery was screened with a newly developed and more accurate quick color image scan ultrasound technique and a lead 2 EKG rhythm strip was used to find atrial fibrillation. The focus in this protocol was on the rapid detection of the three immediate causes of stroke and did not include a lengthy questionnaire or long counseling. A cholesterol determination was not included and there was little or no cost to the participants. In stroke screening trials of the new protocol at two institutions, 176 participants were screened at a rate of one every 2.7 minutes. There were 26 with > 50% carotid stenosis, 16 with previously unknown cardiac arrhythmias and 104 had hypertension. It was concluded that this protocol provides an accurate, rapid and cost-effective means of screening for the three immediate causes of stroke and can on broad application result in significant stroke reduction.

Maximizing the cost-effectiveness of lipid-lowering therapy

Cardiovascular disease, including coronary heart disease, is the leading cause of death both in men and in women in the United States. The purpose of this review is to describe the effectiveness of lipid-lowering therapy in reducing cardiovascular morbidity and mortality, which has recently been extended to patients with mild to moderate hypercholesterolemia, and the cost of providing therapy, which would be prohibitive if all persons with hypercholesterolemia received treatment. Cost-effectiveness analysis provides a rational means of allocating limited health care resources by allowing the comparison of the costs of lipid-lowering therapy, in particular, therapy with beta-hydroxy-beta-methylglutaryl-CoA (coenzyme A) reductase inhibitors (statins), with the costs of atherosclerosis that could be prevented by lowering cholesterol. To extend the benefits of treatment to the large number of persons not receiving therapy, we need to implement more cost-effective treatment by improving risk assessment, increasing treatment effectiveness, and reducing the cost of therapy.

Is routine duplex ultrasound surveillance after carotid endarterectomy cost-effective?

BACKGROUND

Although duplex ultrasound surveillance of patients after carotid endarterectomy (CEA) is routinely performed, the use of this policy has been questioned. We evaluated the cost-effectiveness of this strategy.

METHODS

Using a decision-analytic Markov model that depicts the natural history of patients after CEA, we compared a strategy of duplex ultrasound surveillance to a strategy of no surveillance. Probability estimates were derived from the literature and costs were obtained from the hospital's cost accounting system. Sensitivity analyses were performed to test the robustness and stability of our base-case conclusion to variations in the underlying assumptions.

RESULTS

Using baseline estimates we determined that duplex ultrasound surveillance after CEA reduced the incidence of stroke; however, this required significant additional expense, which resulted in an incremental cost-effectiveness ratio of $126,950. This ratio could decrease to a more acceptable level (less than $100,000) if a subset of patients could be identified whose rate of progression to greater than 80% stenosis exceeded 6% per year or whose stroke rate associated with uncorrected asymptomatic stenosis exceeded 2.6% per year. Also, the cost-effectiveness ratio was reduced to less than $100,000 if patients were younger than 55 years old at the time of initial CEA or if the cost of CEA could be reduced to less than $7,000.

CONCLUSIONS

Duplex ultrasound surveillance after CEA is associated with an unfavorable cost-effectiveness ratio. However, this strategy may be cost-effective in younger patients or in those patients who have a more progressive form of disease.

Cost-effectiveness of screening for asymptomatic carotid stenosis

PURPOSE

The benefit of carotid endarterectomy for patients who are asymptomatic with > 60% carotid stenosis has been established by the Asymptomatic Carotid Atherosclerosis Study (ACAS). Which screening strategy is most appropriate is still unclear. This study assessed the cost-effectiveness of ultrasound screening for asymptomatic carotid stenosis.

METHODS

Cost-effectiveness analysis was performed with a Markov model and with data from ACAS and other studies.

RESULTS

For 60-year-old patients with a 5% prevalence of 60% to 99% asymptomatic stenosis, duplex ultrasound screening increased average quality-adjusted life years (QALY; 11.485 vs 11.473) and lifetime cost of care ($5500 vs $5012) under base-case assumptions. The incremental cost per QALY gained (cost-effectiveness ratio) was $39,495. Screening was cost-effective with the following conditions: disease prevalence was 4.5% or more, the specificity of the screening test (ultrasound) was 91% or more, the stroke rate of patients who were medically treated was 3.3% or more, the relative risk reduction of surgery was 37% or more, the stroke rate associated with surgery was 160% or less than that of the North American Symptomatic Carotid Endarterectomy Trial or ACAS perioperative complication rates, and the cost of ultrasound screening was $300 or less. A one-time screening, compared with a screening every 5 years, had more QALY (11.485 vs 11.482) and lower cost ($5500 vs $5790). Screening without arteriography, compared with screening with arteriographic verification, provided few additional QALYs (11.486 vs 11.485) at additional cost ($6896 vs $5500). The cost-effectiveness ratio was sensitive to assumptions about the stroke rate of patients who were asymptomatic and other variables.

CONCLUSIONS

Screening for asymptomatic carotid stenosis can be cost-effective when both screening and carotid endarterectomy are performed in centers of excellence.

A cost comparison of balloon angioplasty and stenting versus endarterectomy for the treatment of carotid artery stenosis

PURPOSE

Percutaneous transluminal angioplasty with stenting (PTAS) of the carotid artery has been advocated as an alternative treatment for high-grade stenosis. Rationale for this approach includes less morbidity, shorter recovery, and lower cost when compared with carotid endarterectomy (CEA).

METHODS

The clinical results and hospital charges of patients who underwent elective treatment for carotid stenosis were reviewed. During a concurrent 14-month period, 218 patients were admitted 229 times for 234 procedures for the treatment of 239 carotid bifurcation stenoses, 109 by PTAS and 130 by CEA. Hospital charges were reviewed for each hospitalization and were categorized according to radiology, operating room, cardiac catheterization laboratory, and all other hospital charges.

RESULTS

The combined incidence of postprocedure strokes and deaths were: PTAS, eight strokes (7.7%) and one death (0.9%); CEA, two strokes (1.5%) and two deaths (1.5%). Total hospital charges per admission for the two groups were $30,140 for PTAS and $21,670 for CEA. The average postprocedure length of stay for PTAS was 2.9 days (median, 2 days) and for CEA was 3.1 days (median, 3 days). Cardiac catheterization laboratory charges for the PTAS group were $12,968, whereas the operating room charges for the CEA group were $4263. When hospitalizations that were extended by complications were excluded, the average total charges for the PTAS group (n = 84) dropped to $24,848 (mean length of stay, 1.9 days) and for the CEA group (n = 111) to $19,247 (mean length of stay, 2.6 days).

CONCLUSIONS

After evaluating hospital charges, PTAS for the treatment of carotid stenosis cannot currently be justified on the basis of reduced costs alone. With future cost-containing measures, total hospital charges can be reduced in both groups.

Improving the cost-effectiveness of carotid endarterectomy

PURPOSE

Carotid endarterectomy (CEA) has been shown to significantly reduce the risk of stroke caused by carotid artery stenosis. Limiting the costs of CEA without increasing the risks will improve the cost-effectiveness of this procedure.

METHODS

Results were prospectively collected from 63 consecutive CEAs performed in 60 patients who were entered into a clinical pathway for CEA that included avoidance of cerebral arteriography, preferential use of regional anesthesia, selective use of the intensive care unit (ICU), and early hospital discharge. The mortality rate, complications, hospital costs, and net income in these patients were then compared with results from 45 CEAs performed in 42 consecutive patients immediately before beginning the CEA pathway. Age, comorbid risk factors, incidence of symptoms, and degree of carotid artery stenosis were similar in both patient groups.

RESULTS

The rates of mortality and complications associated with CEA were low (mortality rate, 0%; stroke, 0.9%; transient ischemic attack, 2.8%) and did not vary between the two groups. Implementation of the CEA pathway resulted in significant (p < 0.001) reductions in the use of arteriography (74% to 13%), general anesthesia (100% to 24%), ICU use (98% to 30%), and mean hospital length of stay (5.8 days to 2.0 days). These changes resulted in a 41% reduction in mean total hospital cost ($9652 to $5699) and a 124% increase in mean net hospital income ($1804 to $4039) per CEA (p < 0.01). For the 39 patients (62%) who achieved all elements of the CEA pathway, the mean hospital length of stay was 1.3 days, the mean hospital cost was $4175, and the mean hospital income was $4327.

CONCLUSIONS

Costs associated with CEA can be reduced substantially without increased risk. This makes CEA an extremely cost-effective treatment of carotid disease against which new therapeutic approaches must be measured.

Cost-effectiveness of carotid endarterectomy in asymptomatic patients

PURPOSE

The purpose of this study was to determine the cost-effectiveness of carotid endarterectomy for treating asymptomatic patients with > or = 60% internal carotid stenosis, based on outcomes reported in the Asymptomatic Carotid Atherosclerosis Study (ACAS).

METHODS

A cost-effectiveness analysis was performed using a Markov decision model in which the probabilities for base-case analysis (average age, 67 years; 66% male; perioperative stroke plus death rate, 2.3%; ipsilateral stroke rate during medical management, 2.3% per year) were based on ACAS. The model assumed that patients who had TIAs or minor strokes during medical management crossed over to surgical treatment, and used the NASCET data to model the outcome of these now-symptomatic patients. Average cost of surgery ($8500), major stroke ($34,000 plus $18,000 per year), and other costs were based on local cost determinations plus a review of the published literature. Cost-effectiveness was calculated as the incremental cost of surgery per quality-adjusted life year (QALY) saved when compared with medical treatment, discounting at 5% per year. Sensitivity analysis was performed to determine the impact of key variables on cost-effectiveness.

RESULTS

In the base-case analysis, surgical treatment improved quality-adjusted life expectancy from 7.87 to 8.12 QALYs, at an incremental lifetime cost of $2041. This yielded an incremental cost-effectiveness ratio of $8,000 per QALY saved by surgical compared with medical treatment. The high cost of care after major stroke during medical management largely offset the initial cost of endarterectomy in the surgical group. Furthermore, 26% of medically managed patients eventually underwent endarterectomy because of symptom development, which also decreased the cost differential. Sensitivity analysis demonstrated that the relative cost of surgical treatment increased substantially with increasing age, increasing perioperative stroke rate, and decreasing stroke rate during medical management.

CONCLUSION

For the typical asymptomatic patient in ACAS with > or = 60% carotid stenosis, our results indicate that carotid endarterectomy is cost-effective when compared with other commonly accepted health care practices. Surgery does not appear cost-effective in very elderly patients, in settings where the operative stroke risk is high, or in patients with very low stroke risk without surgery.

Cost-effectiveness of screening for asymptomatic carotid atherosclerotic disease

BACKGROUND AND PURPOSE

The value of screening for asymptomatic carotid stenosis has become an important issue with the recently reported beneficial effect of endarterectomy. The purpose of this study is to evaluate the cost-effectiveness of using Doppler ultrasound as a screening tool to select subjects for arteriography and subsequent surgery.

METHODS

A computer model was developed to simulate the cost-effectiveness of screening a cohort of 1000 men during a 20-year period. The primary outcome measure was incremental present-value dollar expenditures for screening and treatment per incremental present-value quality-adjusted life-year (QALY) saved. Estimates of disease prevalence and arteriographic and surgical complication rates were obtained from the literature. Probabilities of stroke and death with surgical and medical treatment were obtained from published clinical trials. Doppler ultrasound sensitivity and specificity were obtained through review of local experience. Estimates of costs were obtained from local Medicare reimbursement data.

RESULTS

A one-time screening program of a population with a high prevalence (20%) of > or = 60% stenosis cost $35130 per incremental QALY gained. Decreased surgical benefit or increased annual discount rate was detrimental, resulting in lost QALYs. Annual screening cost $457773 per incremental QALY gained. In a low-prevalence (4%) population, one-time screening cost $52588 per QALY gained, while annual screening was detrimental.

CONCLUSIONS

The cost-effectiveness of a one-time screening program for an asymptomatic population with a high prevalence of carotid stenosis may be cost-effective. Annual screening is detrimental. The most sensitive variables in this simulation model were long-term stroke risk reduction after surgery and annual discount rate for accumulated costs and QALYs.

Who needs surveillance of the contralateral carotid artery?

BACKGROUND

Although the value of carotid endarterectomy has been proven, postoperative surveillance remains controversial. The purpose of this study was to determine the natural history of disease progression in the contralateral carotid artery by duplex surveillance, and to assess the cost of stroke prevention on this contralateral side.

METHODS

Vascular laboratory records were reviewed to identify carotid endarterectomy patients who had two or more duplex studies between 1984 and 1995. Critical stenosis was defined as > or = 75% area reduction.

RESULTS

In all, 324 patients were followed up with duplex scans for 1 month to 11 years (mean 30.3 months). The only factors that correlated with progression to critical stenosis were age and initial stenosis. Overall, 19.5% of patients progressed to critical stenosis within 5 years while the high-risk groups with age > 65 years or initial stenosis > or = 50% progressed to critical disease in 27% and 39%, respectively (P < or = 0.05). The cost per stroke prevented ranged from $143,500 to $418,200 when stratified by initial stenosis.

CONCLUSION

Patients who have undergone a carotid endarterectomy demonstrate a propensity for progression of carotid stenosis in the unoperated (contralateral) artery. The cost/benefit ratio may be improved by varying the intensity of duplex surveillance of the contralateral carotid based on the patient's age and initial degree of stenosis.

Cost reduction by combined carotid endarterectomy and coronary artery bypass grafting

A significant cost reduction is likely if patients who require coronary artery bypass grafting with significant carotid stenosis have simultaneous carotid endarterectomy and bypass grafting, provided risk is not increased. To investigate this issue, we retrospectively identified cases from February 1977 to May 1994 with first-time isolated carotid endarterectomy, coronary bypass, or combined procedures. In the isolated carotid endarterectomy population, median age was 69 years and 58% (85/146) were male, as compared with 68 years and 68% (68/100) male in the combined group; median age of the coronary bypass cohort was 65 years and 76% (381/500) male. A significantly higher percentage of patients in the coronary bypass versus combined group were in New York Heart Association functional class IV. In the combined group there was a significantly higher incidence of older age, diabetes, hypertension, hyperlipidemia, renal failure, and congestive heart failure. There was no difference among the three groups with respect to hospital mortality (0%, 3.4%, and 4.0%, respectively) and permanent stroke (0.7%, 1.2%, and 0%, respectively). Hospital costs were $4,896, $10,959 and $11,089, respectively, with a savings of $4,766 (30%), and Medicare hospital reimbursement was $8,575, $23,071, and $23,071, respectively, with a savings of $10,077 (25.3%). Thus, in appropriate patients, a combined procedure is cost effective, eliminating a second surgical procedure and the cost of the postoperative stay (3.7 +/- 2.4 days) associated with isolated carotid endarterectomy. Risk of permanent stroke or death is not increased.

[Evoked potentials for quality assurance in carotid surgery--a cost effectiveness analysis]

In order to evaluate the relation between costs and benefit of the use of a temporary shunt during surgery of the carotid artery, we analysed 356 patients undergoing 401 operations of the carotid artery in a period from January 1991 to August 1995 in a retrospective study. The morbidity and mortality during hospital stay were 1.75% respectively 0.75% referring to neurological outcome and death. The potential to economize surgery of the carotid artery by recording the somatosensory evoked potentials in order to select the patients requiring a temporary shunt would be 4.1% of the payment which will be payed from 1996 by the social insurance for carotid endarterectomy. These savings can be realized without loss of quality or higher risk for the patient.