Cost savings associated with the nonroutine use of carotid angiography

Limited economic evidence of carotid artery stenosis diagnosis and treatment: a systematic review

The objective of this article is to assess the availability and validity of economic evaluations of carotid artery stenosis (CS) diagnosis and treatment.

DESIGN

Systematic review of economic evaluations of the diagnosis and treatment of CS.

METHODS

Systematic review of full economic evaluations published in Medline and Google Scholar up until 28 February 2012. Based on economic checklists (Evers and Philips), the identified studies were classified as high, medium, or low quality.

RESULTS

Twenty-three evaluations were identified. The study quality ranged from 26% to 84% of all achievable points (Evers). Seven studies were of high, eight of medium and eight of low quality. No comparison was made between carotid angioplasty and stenting (CAS) and best medical treatment (BMT). For subjects with severe stenosis, comparisons of carotid endarterectomy (CEA) and BMT were also missing. Three of five studies dealing with pre-operative imaging found that duplex Doppler ultrasound (US) was cost-effective compared with carotid angiogram (AG).

CONCLUSIONS

There is a huge lack of high-quality studies and of studies that confirm published results. Also, for a given study quality, the most cost-effective treatment strategy is still unknown in some cases ('CAS' vs. 'BMT', 'US combined with magnetic resonance angiography supplemented with AG' vs. 'US combined with computer tomography angiography').

Intra-Arterial Thrombolysis for Basilar Artery Thrombosis

The poor prognosis for recovery of basilar artery thrombosis has led to the adoption at many institutions of intra-arterial thrombolysis as part of clinical care. However, because neither randomized clinical trials nor observational data provide evidence for treatment efficacy and there are substantial risks and costs associated with this procedure, this treatment should only be performed in the context of a randomized, controlled clinical trial subject to appropriate Institutional Review Board review and independent safety monitoring.

Diagnostic efficacy of SonoVue®, a second generation contrast agent, in the assessment of extracranial carotid or peripheral arteries using colour and spectral Doppler ultrasound: a multicentre study

The purpose of this study was to demonstrate the improvement in diagnostic quality and diagnostic accuracy of SonoVue microbubble contrast-enhanced ultrasound (CE-US) versus unenhanced ultrasound imaging during the investigation of extracranial carotid or peripheral arteries. 82 patients with suspected extracranial carotid or peripheral arterial disease received four SonoVue doses (0.3 ml, 0.6 ml, 1.2 ml and 2.4 ml) with Doppler ultrasound performed before and following each dose. Diagnostic quality of the CE-US examinations was evaluated off-site for duration of clinically useful contrast enhancement, artefact effects and percentage of examinations converted from non-diagnostic to diagnostic. Accuracy, sensitivity and specificity were assessed as agreement of CE-US diagnosis evaluated by an independent panel of experts with reference standard modality. The median duration of clinically useful signal enhancement significantly increased with increasing SonoVue doses (p< or =0.002). At the dose of 2.4 ml of SonoVue, diagnostic quality evaluated as number of inconclusive examinations significantly improved, falling from 40.7% at baseline down to 5.1%. Furthermore, SonoVue significantly (p<0.01) increased the accuracy, sensitivity and specificity of assessment of disease compared with baseline ultrasound. SonoVue increases the diagnostic quality of Doppler images and improves the accuracy of both spectral and colour Doppler examinations of extracranial carotid or peripheral arterial disease.

Carotid endarterectomy then and now: outcome and cost-effectiveness of modern practice

BACKGROUND

During the past decade, our practice of performing carotid endarterectomy (CEA) has changed dramatically, most notably by an abrupt shift from routine to selective preoperative angiography, reliance on defined care plans with full-time nurse practitioner oversight, and increasing reliance on eversion endarterectomy and cervical block anesthesia. This study was designed to determine whether these shifts in policy have been associated with lower costs without sacrificing clinical outcome.

METHODS

All patients undergoing CEA from July 1993 to December 2000 were identified, and inpatient and outpatient charts were reviewed. Cost data were obtained from the central hospital accounting system and converted to 2001 dollars. Thirty-day outcomes and costs were quantified each year and compared between each of 2 temporally well-defined groups: those undergoing "routine" versus "selective" angiography and those cared for before and after defined patient care protocols were instituted.

RESULTS

A total of 1168 CEAs were analyzed. Thirty-day combined stroke and death rate was 3.1%, and no trends or significant differences over time were seen. From 1993 to 2000 the cost of CEA fell from $9302 to $6216 (P<.0002), and length of stay was reduced 1 full day (P=.005). Institution of "selective" angiography was associated with an immediate cost savings of approximately $2000 per case (P<.0001), and nurse practitioner oversight along with institution of defined clinical protocols with a $530 (P<.05) decline in nonoperating room-related costs.

CONCLUSIONS

Changes in policy from routine to selective angiography, reliance on defined postoperative care pathways, eversion endarterectomy, and cervical block anesthesia have been associated with significant cost savings, with no compromise in clinical outcome at our institution.

Improvement in accuracy of diagnosis of carotid artery stenosis with duplex ultrasound scanning with combined use of linear array 7.5 MHz and convex array 3.5 MHz probes: validation versus 489 arteriographic procedures

OBJECTIVE

Validity of a method to improve the accuracy of carotid artery duplex scanning was tested in comparison with arteriography.

STUDY DESIGN

In 489 patients who had not previously undergone arteriography, 978 carotid arteries were examined with duplex ultrasound scanning. In method A, a linear array 7.5 MHz transducer with pulsed-wave 4.7 MHz Doppler scanning was used. For the diagnosis and grading of carotid stenosis, peak systolic and end-diastolic velocity of the Doppler waves were recorded. Method B consisted of complete ultrasound imaging and color-flow mapping with a convex array 3.5 MHz transducer with pulsed-wave 2.8 MHz Doppler scanning in all patients who had previously undergone method A. Further velocity measurements were performed at the sites of stenosis. The results of methods A and B were compared with data from neurologic assessment and arteriographic studies.

RESULTS

Method B showed significantly higher diagnostic agreement with arteriography than did method A (K 95% confidence interval [CI], 0.87-0.93 vs 0.79-0.85; P <.05), and the number of mistakes in grading stenosis was significantly lower (primarily because of decreased overestimation) in patients with internal carotid kinking (>60 degrees of angulation) (P <.05), distal stenosis (>20 mm from bifurcation) (P <.01), or wide acoustic shadowing (>1 cm) (P <.01) and in those without these conditions (P <.05). Compared with arteriography, diagnostic accuracy with the new method proved higher for carotid stenoses 50% or greater, 60% or greater, 70% or greater, and 80% or greater; no statistically significant difference was found for carotid stenosis 96% or greater or for carotid occlusion. Compared with data from neurologic assessment and arteriography, method B proved more accurate than method A in designating patients for carotid endarterectomy (P =.014).

CONCLUSIONS

The new method significantly improved diagnostic reliability of duplex ultrasound scanning, especially in carotid arteries with kinking, distal stenosis, or wide acoustic shadowing (32.2% of all arteries studied). In clinical practice, we suggest additional use of a lower frequency transducer in cases in which these three conditions are found or suspected at first scanning.

Cost of identifying patients for carotid endarterectomy

BACKGROUND AND PURPOSE

The cost of carotid endarterectomy (CEA) usually considers only the cost of the preoperative investigations and the procedure for the individual patient but ignores the cost incurred in selecting a patient from a referred "pool" of potential candidates or the "total direct program cost." The aim of this study was to estimate the total direct program cost (workup and procedure) of CEA in a large major teaching hospital in Edinburgh, Scotland using a retrospective study design.

METHODS

Participants were patients with transient ischemic attacks and mild strokes referred to the neurovascular clinics for assessment, investigation, and possible CEA. The "workup" was defined as the clinical consultation, carotid duplex, 1 follow-up visit, and a catheter angiogram where indicated. We used data routinely collected from the neurovascular clinics during a 1-year period to estimate the workup cost of patients who might be suitable for CEA. The CEA procedure cost was estimated prospectively in a concurrent study. Estimated costs were applied to the proportions assessed at the different levels of investigation to determine the total direct program cost of CEA.

RESULTS

A total of 790 new patients with symptoms suggestive of transient ischemic attacks and mild strokes were identified. Four hundred one (51%) patients were referred for carotid duplex. Duplex identified 78 (10%) with carotid stenosis of > or =70%. Of the total of 790 patients, 26 (3.3%) had catheter angiogram and 18 (2.3%) had CEA. The total direct program cost to investigate this cohort was about 207 000 pounds sterling, with 68% (140 000 pounds sterling) of the cost incurred before any surgery was performed.

CONCLUSION

The cost of identifying suitable patients for carotid surgery is quite high, with more than 30% of the cost attributed to the initial consultation at the neurovascular clinics. The cost of preventing 1 stroke by CEA is in the region of 100 000 pounds sterling at 1997/1998 prices if all the costs incurred in the workup of a cohort for potential CEA are included.

Costs and benefits of carotid endarterectomy and associated preoperative arterial imaging: a systematic review of health economic literature

BACKGROUND AND PURPOSE

Carotid endarterectomy (CEA) reduces the risk of stroke in patients with severe stenosis of the internal carotid artery. However, the cost implications of this procedure have not yet been satisfactorily addressed. The objective of this systematic review was to critically appraise the studies addressing the economic implications of CEA and the associated preoperative arterial imaging.

METHODS

A systematic search strategy was developed to identify research articles related to the economic evaluation of CEA and the associated preoperative imaging. MEDLINE, EMBASE, and BIOSIS were electronically searched, and reference lists from identified studies were searched manually. Methods used to critically appraise these studies followed proposed guidelines for an economic evaluation that addresses 10 distinct aspects under 3 separate headings.

RESULTS

Studies identified were either partial economic or full economic evaluations, with the majority coming from the United States. The methodological quality seems to have improved over time. The studies that assessed cost-effectiveness of CEA were all modeling studies; although the same baseline parameters were used, divergent conclusions were reached. Variation in the cost estimates of CEA ($9500 to $11 500) in the same health care system was also observed in the studies reporting only on the cost of carotid surgery. For a symptomatic patient, the benefit of CEA ranged from 0.35 quality adjusted life years (QALYs) (4.2 months) at a cost of $4100 per QALY to 0.93 QALYs (11.2 months) at a cost of $434 per QALY. For an asymptomatic patient, the cost-effectiveness of CEA varied from 0.15 QALYs (1.8 months) at a cost of $52 700 per QALY to 0.25 QALYs (3 months) at a cost of $8004 per QALY.

CONCLUSIONS

Divergent conclusions of the cost-effectiveness of CEA were reported from studies that addressed the same questions and using similar parameters in their models. The cost estimates of the procedure and the different time periods used in the studies might explain these inconsistencies. Modeling studies in hypothetical cohorts might also be to blame. The cost-effectiveness of CEA will only definitively be assessed when real patient data are used.

Avaliação carotídea em doentes submetidos a revascularização miocárdica

OBJETIVO: Como a doença carotídea é a principal causa isolada de acidente vascular cerebral de origem tromboembólica, acredita-se ser imprescindível o seu diagnóstico precoce. O presente estudo tem por objetivo realizá-lo, mantendo os conceitos de praticidade e viabilidade econômica, adequando-se às condições socioeconômicas desfavoráveis locais. MÉTODO: No período de 18 meses foram avaliados 50 doentes, sendo 35 homens e 15 mulheres, com média de idade de 67,2 anos. Todos apresentavam indicação de revascularização miocárdica, considerados coronariopatas graves. Avaliou-se a incidência e o grau de estenose carotídea com base no mapeamento dúplex. Da mesma forma, foi avaliada a relação com possíveis fatores de risco: diabetes melito, hipertensão arterial sistêmica, tabagismo, sintomatologia neurológica focal prévia, doença arterial troncular dos membros inferiores e presença de sopro carotídeo. RESULTADOS: A incidência de estenose carotídea hemodinamicamente significativa (>50%) foi de 48%, e crítica (>70%) de 32%. Mostraram-se fatores de risco estatisticamente significativos, antecedentes de diabetes melito, sintomatologia neurológica focal prévia, presença de sopro carotídeo e presença de alterações arteriais tronculares dos membros inferiores. CONCLUSÃO: Concluiu-se que no grupo estudado houve aumento significativo de risco para estenose carotídea hemodinamicamente significativa e crítica, em relação à população geral. Desta forma, justifica-se o rastreamento ultra-sonográfico para doença carotídea em doentes coronariopatas, principalmente quando os fatores de risco significativos se fizerem presentes.

Influence of NASCET/ACAS trial eligibility on outcome after carotid endarterectomy

PURPOSE

Proponents of carotid angioplasty and stenting suggest that "high risk" patients, defined as patients excluded from the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and Asymptomatic Carotid Atherosclerosis Study (ACAS), may have a significantly higher risk of stroke with carotid endarterectomy (CEA). However, this selected patient cohort has been poorly studied.

METHODS

A retrospective review of patients who underwent CEA during a 2-year period at a tertiary referral institution was performed. Each patient was evaluated and categorized, according to the exclusion criteria, by NASCET and ACAS standards. Statistical analysis using chi(2) and Fisher exact tests was performed.

RESULTS

There were 366 CEAs performed on 348 patients, including 32 (8.7%) for recurrent stenosis. A subgroup of 169 (46.2%) patients were trial ineligible. Focal ipsilateral symptoms were present in 148 (40.4%) of the patients. There were 9 (2.5%) strokes and 1 (0.3%) death, secondary to a major stroke, for an overall stroke and death rate of 2.5%. Trial-eligible patients had a stroke/death rate of 1.5% (3/197) while trial-ineligible patients had a 3.6% (6/169) stroke/death rate (P = .17).

CONCLUSION

Patients who were considered high risk for CEA as defined by trial ineligibility were common, comprising approximately half of our patients. Although trial-ineligible patients had a nonsignificant trend toward higher neurologic morbidity when compared with the eligible group, the risks were still comparable with NASCET/ACAS results. CEA was a safe procedure even in this "high risk" group. As such, ineligibility for a randomized carotid intervention trial should not be employed as a "de novo" indication for carotid stenting.

Value of the CT angiography in the diagnosis of common carotid artery bifurcation disease: CT angiography versus digital subtraction angiography and color flow Doppler

OBJECTIVE

assessment of the degree of stenosis is the central point in the treatment of carotid stenosis. The purpose of our study was to assess whether invasive CT angiography (CTA) is a feasible alternative to the current invasive gold standard carotid digital subtraction angiography (DSA) and the current non-invasive gold standard color flow doppler.

SUBJECTS AND METHODS

about 178 patients with cerebrovascular disease underwent digital subtraction angiography (DSA), CFD and CTA. CTA was performed on a Somatom plus 4 (Siemens, Erlangen Germany). CT was performed with 2/3/2 (collimation/table feed/reconstruction interval) or 2/3/1 mm, start delay 15-20 s, flow 2.5-3.0 ml/s, using 120 ml non-ionic contrast medium (300 mg J/ml). Quantification of degree of stenosis was based on the perfused area in the axial slices. Plaque morphology (soft and hard) and ulceration were evaluated.

RESULTS

CTA detected nine cases of significant stenosis, which had been underestimated by DSA. CTA failed in two cases of a membraneous stenosis, which were underestimated, and in two cases with teeth artifacts. Calcifications were more readily appreciated by CTA than in CFD. In this respect, both methods were superior to DSA. CFD, DSA and CTA had a sensitivity of 100% for occlusions, respectively.

CONCLUSION

CT angiography is useful in case of inconclusive CFD in the pre- and postoperative phase, and as a third modality in case of disagreement between DSA and CFD.

Colour flow Doppler ultrasound of the carotid bifurcation: can it replace routine angiography before carotid endarterectomy?

The objective of this study was to assess the diagnostic accuracy of colour flow Doppler ultrasound (CFD) and its potential to replace digital subtraction angiography (DSA) before carotid endarterectomy (CEA). All patients undergoing CFD of the carotid bifurcation in our department over a period of 1-1/2 years for whom both CFD and DSA results were available were included in the study. We evaluated the feasibility of CFD, its diagnostic accuracy and its potential to diagnose clinically significant stenosis (50%, 70% and 90% NASCET type diameter stenosis) compared with DSA. 225 carotid bifurcations in 116 patients met the criteria for evaluation (biplane arterial DSA without superimposition). Data analysis yielded the following diagnostic performance of CFD: sensitivity for a 50% stenosis 91.4% (95% confidence interval (CI) 83.3--96.2%), specificity 93.2% (95% CI 87.1--96.8%) and accuracy 92.4% (95% CI 88.4--95.4%); sensitivity for a 70% stenosis 89.2% (95% CI 81.9--94.1%), specificity 96.2% (95% CI 90.5--98.6%) and accuracy 92.4% (95% CI 88.4--95.4%). In 9 of 116 cases, carotid angiography was used to evaluate inconclusive CFD results. DSA disclosed relevant information not suspected by CFD in only 1 of the 116 cases. Thus, 91% (106/116) of the angiographies could have been dispensed with without loss of information. One major stroke occurred during diagnostic DSA. We conclude that DSA of the carotid arteries is unnecessary when CFD is unequivocal. The diagnostic gain of DSA must be counterweighted against its potential risks.

Carotid arteriography impacts carotid stenosis management

Recent literature advocates carotid endarterectomy on duplex alone. The authors hypothesized that carotid angiography adds information that alters clinical management in a substantial number of patients compared to the use of carotid duplex examination alone. The records of 182 consecutive patients who underwent carotid artery duplex and subsequent carotid/cerebral angiography for suspected carotid artery stenosis between January 1998 and April 1999 were reviewed retrospectively. Carotid artery duplex examinations were stratified based on stenosis: < or =39%, 40% to 59%, 60% to 79% (moderate), 80% to 99% (severe), 100%. Carotid stenosis on angiograms was determined by NASCET criteria. New information found at angiography included vertebral, subclavian, or arch atherosclerosis, intracranial pathosis, or a change in duplex stenosis category to a degree of stenosis not requiring surgery. Clinical importance was attributed to angiograms that altered the patients' management plan. Angiography provided additional information in 53% (97/182) of patients. Vertebral disease was found in 25.1%, subclavian disease in 16.4%, intracranial disease in 15.3%, aortic arch disease in 3.3%. Patient treatment was altered in 30% (55/182). Angiographic findings downgraded the stenosis to medical therapy in 20.9% (38/182). The surgical plan was influenced in 5.5% (10/182). Nine intracranial aneurysms were discovered. Carotid angiography was essential for vascular bypass surgery planning in 3.3% (6/182). Angioplasty was performed in 2.2% (4/182). The accurate determination of stenosis is critical in determining optimal treatment of patients with carotid artery stenosis. Routine carotid angiography remains valuable in the clinical treatment of these patients.

Cost Containment in Vascular Surgery

In the last decade, the delivery of health care and the role of the physician have undergone radical change. With the ad vent of managed care and the tightening of restrictions by Medicare and insurance companies, physicians have been required to review, re-engineer, and revitalize their role. Increasing financial pressures at the hospital level have caused administrators to cut costs at all levels. It is imper ative that physicians take an active role in cost containment so that the quality of care is not sacrificed. Cost containment in vascular surgery is an urgent priority in health care. Copyright © 2000 by W.B. Saunders Company.

Carotid endarterectomy: the financial impact of practice changes

PURPOSE

New techniques in the management of extracranial carotid occlusive disease have focused attention on the outcome and economics of carotid endarterectomy (CEA). Changing practice patterns for CEA must be assessed to allow accurate comparisons. The purpose of this study was to evaluate the effect of practice modifications related to CEA on patient outcome and cost data.

METHODS

Data on patients undergoing CEAs at a single institution from fiscal year 1992 to 1998 were prospectively collected and entered into a computerized database. Records were reviewed for patient demographics and outcome with regard to stroke and death. Selected years that corresponded to transitions in perioperative management were audited for complete hospital financial information from.

RESULTS

We performed 960 CEAs during the study period, with a combined stroke and death rate of 1.1%. Inflation-adjusted hospital costs per patient in 1998 dollars for the years 1992, 1996, and 1998 were $5494, $4476, and $3350, respectively. In 1998, costs for patients who required arteriography were $1825 greater than those operated on during duplex scan examination alone in 1998. Statistically significant differences occurred in the year-to-year comparisons in the use of arteriography, intensive care unit monitoring, same day admissions, and length of stay. There were no statistically significant differences in the stroke and death rate between years.

CONCLUSION

Practice changes related to CEA have resulted in significant savings without detriment in patient outcome. Comparisons between CEA and endovascular techniques will need to be evaluated within this context. Given these advances in perioperative management, it will be difficult to justify carotid stenting on the basis of current economic considerations.

New duplex ultrasound scan criteria for managing symptomatic 50% or greater carotid stenosis

PURPOSE

The North American Symptomatic Carotid Endarterectomy Trial (NASCET) showed that selected patients benefited from surgery when their carotid artery was 50% or more stenosed. This study assessed the accuracy of color-flow duplex ultrasound scanning (DUS) parameters to detect 50% or greater carotid artery stenosis and to determine the situations in which carotid endarterectomy (CEA) without angiography could be justified.

METHODS

From March 1, 1995, to December 1, 1995, all patients considered for CEA were studied with DUS and carotid angiography. Results of the two tests were blindly compared. DUS measurements of internal carotid artery (ICA) peak systolic velocity (PSV), end diastolic velocity, and ratio of the ICA to common carotid artery PSV (ICA/CCA) were subjected to receiver operator characteristic curve analysis to determine the most accurate criterion predicting 50% or greater angiographic stenosis. The criterion for identifying patients for CEA without angiography was selected from criteria with a high positive predictive value (PPV) and sensitivity.

RESULTS

A total of 188 carotid bifurcations were available for comparison. A PSV (ICA/CCA) of 2 or higher was the most accurate criterion for detection of 50% or greater stenosis, with an accuracy rate of 93% (sensitivity, 96%; specificity, 89%; PPV, 92%). A PSV (ICA/CCA) of 3.6 or higher was the best criterion for identifying candidates for CEA who had not undergone earlier angiography, with PPV, sensitivity, specificity, and accuracy rates of 98%, 77%, 98%, and 86%, respectively.

CONCLUSION

These redefined criteria detect the NASCET-defined threshold level of 50% or greater ICA stenosis, above which CEA results in stroke reduction. A management algorithm based on these criteria should help to minimize both angiography and unnecessary intervention.