Common Reasons That Asymptomatic Patients Who Are 65 Years and Older Receive Carotid Imaging

William M. Feinberg Lecture: Asymptomatic Carotid Stenosis: Current and Future Considerations

Asymptomatic high-grade carotid stenosis is an important therapeutic target for stroke prevention. For decades, the ACAS (Asymptomatic Carotid Atherosclerosis Study) and ACST (Asymptomatic Carotid Surgery Trial) trials provided most of the evidence supporting endarterectomy for patients with asymptomatic high-grade stenosis who were otherwise good candidates for surgery. Since then, transfemoral/transradial carotid stenting and transcarotid artery revascularization have emerged as alternatives to endarterectomy for revascularization. Advances in treatments against atherosclerosis have driven down the rates of stroke in patients managed without revascularization. SPACE-2 (Stent-Protected Angioplasty Versus Carotid Endarterectomy-2), a trial that included endarterectomy, stenting, and medical arms, failed to detect significant differences in stroke rates among treatment groups, but the study was stopped well short of its recruitment goal. CREST-2 (Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis Trial) will be able to clarify whether revascularization by stenting or endarterectomy remains efficacious under conditions of intensive medical management. Transcarotid artery revascularization has a favorable periprocedural risk profile, but randomized trials comparing it to intensive medical management are lacking. Features like intraplaque hemorrhage on MRI and echolucency on B-mode ultrasonography can identify patients at higher risk of stroke with asymptomatic stenosis. High-grade stenosis with poor collaterals can cause hemispheric hypoperfusion, and unstable plaque can cause microemboli, both of which may be treatable risk factors for cognitive impairment. Evidence that there are patients with carotid stenosis who benefit cognitively from revascularization is presently lacking. New risk factors are emerging, like exposure to microplastics and nanoplastics. Strategies to limit exposure will be important without specific medical therapies.

The role of carotid ultrasound in patients with non-lateralizing neurological complaints

OBJECTIVES

In the United States, approximately 18-25% of carotid duplex ultrasound (CUS) studies are ordered to assess patients with non-lateralizing neurological complaints such as syncope, blurry vision, lightheadedness, headache, and altered mental status. The purpose of this study is to evaluate the benefit of CUS in the evaluation of patients presenting with non-lateralizing signs or symptoms.

MATERIALS AND METHODS

We conducted a retrospective analysis to assess the degree and laterality of carotid stenosis among patients with non-lateralizing neurological complaints who underwent CUS interpreted by certified vascular neurologists over a period of 3 years. The primary endpoint was to identify the prevalence of moderate-to-severe carotid artery stenosis among 280 patients who met inclusion criteria.

RESULTS

A total of 17.7% of CUS studies were ordered for non-lateralizing symptoms. Two hundred and sixty-one patients (93.21%) had either normal imaging or mild carotid stenosis of <50%. Nineteen patients (6.79%) were found to have stenosis of ≥50%. In this subgroup, age and known preexisting carotid artery atherosclerotic disease were the only variables found to have a statistically significant association with the level of stenosis found on CUS. Two patients with asymptomatic stenosis of >70% underwent a revascularization procedure.

CONCLUSION

At least 17.7% of CUS studies were completed for non-lateralizing symptoms. The study is of low-yield with the prevalence of moderate-to-severe stenosis being comparable to that in the general asymptomatic population. We conclude that there is minimal clinical value in the use of CUS to investigate non-lateralizing neurological complaints, resulting in unnecessary healthcare costs.

Use of Neuroimaging for Patients With Dizziness Who Present to Outpatient Clinics vs Emergency Departments in the US

Importance

Overuse of costly neuroimaging technology is associated with low-value care for the prevalent symptom of dizziness. Although quality improvement initiatives have focused on the overuse of computed tomography (CT) scans in emergency departments (EDs), most patients with dizziness present to outpatient clinics. To inform practice and policy, a comprehensive understanding of the uses and costs of neuroimaging across settings and episodes of care is needed.

Objective

To characterize neuroimaging use, timing, and spending as well as factors associated with imaging acquisition within 6 months of presentation for dizziness in outpatient vs ED settings.

Design, Setting, and Participants

This cross-sectional study of commercial and Medicare Advantage claims for 805 454 adults (≥18 years of age) with new diagnoses of dizziness was conducted from January 1, 2006, through December 31, 2015. Data were analyzed from October 1, 2020, to September 30, 2021.

Main Outcomes and Measures

Use of neuroimaging (CT scan, magnetic resonance imaging [MRI], angiography, and ultrasonography) and total spending on neuroimaging were measured. Kaplan-Meier analysis was performed. The associations of neuroimaging with setting, sociodemographic characteristics, and clinicians were estimated with multivariable analyses.

Results

A total of 805 454 individuals with dizziness (502 055 women [62%]; median age, 52 years [range, 18-87 years]) were included in this study; 156 969 (20%) underwent neuroimaging within 6 months of presentation (65 738 of 185 338 [36%] presented to EDs and 91 231 of 620 116 [15%] presented to outpatient clinics). The median time to neuroimaging was 0 days (95% CI, 0-2 days) after ED presentation and 10 days (95% CI, 9-10 days) after outpatient presentation. Neuroimaging was independently associated with advanced age, comorbidity, race and ethnicity, ED presentation, and outpatient clinician specialty. Across sites, a head CT scan was the most used test on presentation date (92% of tests [46 852 of 51 022]). Within 6 months of presentation, a head CT scan was the most used test (47% of all tests [177 949 of 376 149]), followed by brain MRI (25% [93 130 of 376 149]), cerebrovascular ultrasonography (15% [56 175 of 376 149]), and magnetic resonance angiography (9% [34 026 of 376 149]). Of $88 646 047.03 in total neuroimaging spending, MRI accounted for 70% ($61 730 251.95), CT scans for 19% ($16 910 506.24), and ultrasonography for 11% ($10 005 288.84). Per-test median spending ranged from $68.97 (CT scan of the head) to $319.63 (MRI of the brain) among commercially insured individuals and $43.21 (CT scan of the head) to $362.02 (MRI of the orbit, face, and neck) among Medicare Advantage beneficiaries.

Conclusions and Relevance

The findings of this cross-sectional study suggest that use of neuroimaging for dizziness is prevalent across settings. Interventions to optimize the use of neuroimaging must occur early in the patient care journey to discourage guideline-discordant use of CT scans, advocate for judicious MRI use (particularly in ambulatory settings), and account for the effects of price transparency.

Characterizing and quantifying low-value diagnostic imaging internationally: a scoping review

BACKGROUND

Inappropriate and wasteful use of health care resources is a common problem, constituting 10-34% of health services spending in the western world. Even though diagnostic imaging is vital for identifying correct diagnoses and administrating the right treatment, low-value imaging-in which the diagnostic test confers little to no clinical benefit-is common and contributes to inappropriate and wasteful use of health care resources. There is a lack of knowledge on the types and extent of low-value imaging. Accordingly, the objective of this study was to identify, characterize, and quantify the extent of low-value diagnostic imaging examinations for adults and children.

METHODS

A scoping review of the published literature was performed. Medline-Ovid, Embase-Ovid, Scopus, and Cochrane Library were searched for studies published from 2010 to September 2020. The search strategy was built from medical subject headings (Mesh) for Diagnostic imaging/Radiology OR Health service misuse/Medical overuse OR Procedures and Techniques Utilization/Facilities and Services Utilization. Articles in English, German, Dutch, Swedish, Danish, or Norwegian were included.

RESULTS

A total of 39,986 records were identified and, of these, 370 studies were included in the final synthesis. Eighty-four low-value imaging examinations were identified. Imaging of atraumatic pain, routine imaging in minor head injury, trauma, thrombosis, urolithiasis, after thoracic interventions, fracture follow-up and cancer staging/follow-up were the most frequently identified low-value imaging examinations. The proportion of low-value imaging varied between 2 and 100% inappropriate or unnecessary examinations.

CONCLUSIONS

A comprehensive list of identified low-value radiological examinations for both adults and children are presented. Future research should focus on reasons for low-value imaging utilization and interventions to reduce the use of low-value imaging internationally.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO: CRD42020208072.

Diameter Reduction Determined Through Carotid Ultrasound Associated With Cardiovascular and All-Cause Mortality: A Single-Center Experience of 38 201 Consecutive Patients in Taiwan

Background

Few studies have evaluated the prognostic significance of diameter‐based carotid sonographic measurements for mortality. We investigated whether a reduction in diameter of different carotid anatomical segments is associated with cardiovascular and all‐cause mortality in a hospital‐based cohort with universal health care.

Methods and Results

We conducted a retrospective cohort study of 38 201 patients who underwent carotid duplex ultrasound at a medical center in Taiwan. Carotid sonographic parameters were the diameter reduction percentage in carotid bifurcation, the internal carotid artery, the common carotid artery, and the external carotid artery and the overall carotid atherosclerotic burden score, determined by summing the scores from all segments. The vital status was ascertained by linking data to National Death Registry until 2017. During a median follow‐up of 4.2 years, 5644 participants died, with 1719 deaths attributable to cardiovascular diseases. The multivariable‐adjusted hazard ratios (HRs; 95% CIs) for cardiovascular mortality were 1.33 (1.16‒1.53), 1.58 (1.361.84), and 1.89 (1.58, 2.26) for participants with 30% to <40%, 40% to <50%, and ≥50% reduction in carotid bifurcation diameter, respectively, compared with participants with <30% diameter reduction (P for trend <0.001). The corresponding HRs (95% CIs) for all‐cause mortality were 1.25 (1.16‒1.34), 1.42 (1.31‒1.54), and 1.60 (1.45‒1.77), respectively. Diameter reduction at other carotid sites and the carotid atherosclerotic burden score exhibited the same dose–response relationship.

Conclusions

This study suggests that reduction in carotid artery diameter, which can be determined through routinely available sonography, is an independent risk factor for all‐cause and cardiovascular mortality.

Vertigo: Could this Symptom Indicate the Existence of an Unruptured Intracranial Aneurysm?

Background:Unruptured intracranial aneurysms (UIAs) can be presented with various symptoms, including atypical headaches and cranial nerve deficits. Vertigo is often referred in the literature as a coexisting symptom. Our aim was to investigate the importance of vertigo in the UIA symptomatology and present a possible explanation for its existence. Methods:We conducted a retrospective observational multicenter study concerning patients with surgically treated intracranial aneurysms. During a period of 10 years, 1 085 patients with cerebral aneurysms underwent surgery. There were 812 patients with ruptured intracranial aneurysms (RIA) and 273 with UIA. The medical records for each of the 273 patients were analyzed. Results: After the implementation of exclusion criteria, 89 (32.6%) of UIA patients were selected in the study, from which 71 (79.8%) were females and 18 (20.2%) males. The mean age was 56.9 (± 12.876) years old. Vertigo existed in 72 (80.9%), headache in 41 (46.1%) and visual symptoms in 21 (23.6%) patients. No significant correlation (p >0.05) was demonstrated between gender, age or aneurysm location in correlation with vertigo, headache or visual symptoms, apart from a negative significant correlation between age and vertigo (p=0.031). Conclusion:Vertigo is an alarming symptom that could indicate the existence of an UIA. The pathophysiological mechanism could be explained by the formation of an aneurysmal vortex that projects into the parent artery, leading to disturbances in the laminar flow and formation of an irregular/turbulent flow, which potentially affects the cerebral autoregulation and by consequence, the central processing of movement.

Trends in Low-Value Carotid Imaging in the Veterans Health Administration From 2007 to 2016

IMPORTANCE

As part of the Choosing Wisely campaign, primary care, surgery, and neurology societies have identified carotid imaging ordered for screening, preoperative evaluation, and syncope as frequently low value.

OBJECTIVE

To determine the changes in overall and indication-specific rates of carotid imaging following Choosing Wisely recommendations.

DESIGN, SETTING, AND PARTICIPANTS

This serial cross-sectional study compared annual rates of carotid imaging before Choosing Wisely recommendations (ie, 2007 to 2012) and after (ie, 2013 to 2016) among adults receiving care in the Veterans Health Administration (VHA) national health system. Data analysis was performed from April 10, 2019, to November 27, 2019.

EXPOSURES

Release of the Choosing Wisely recommendations.

MAIN OUTCOMES AND MEASURES

Annual rates of overall imaging, imaging ordered for stroke workup, imaging ordered for low-value indications (ie, screening owing to carotid bruit, preoperative evaluation, and syncope). Indications were identified using a text lexicon algorithm based on electronic health record review of a stratified random sample of 1000 free-text imaging orders. The subsequent performance of carotid procedures within 6 months after carotid imaging was assessed.

RESULTS

Between 2007 and 2016, 809 071 carotid imaging examinations were identified (mean [SD] age of patients undergoing imaging, 69 [10] years; 776 632 [96%] men), of which 201 467 images (24.9%) were ordered for low-value indications (67 064 [8.2%] for carotid bruit, 25 032 [3.1%] for preoperative evaluation, and 109 400 [13.5%] for syncope), 257 369 (31.8%) for stroke workup, and 350 235 (43.3%) for other indications. Imaging for carotid bruits declined across the study period while there was no significant change in imaging for syncope or preoperative evaluation. Compared with the 6 years before, during the 4 years following Choosing Wisely recommendations, there was no change in the trend for syncope, a small decline in preoperative imaging (post-Choosing Wisely trend, -0.1 [95% CI, -0.1 to <-0.1] images per 10 000 veterans), and a continued but less steep decline in imaging for carotid bruits (post-Choosing Wisely trend, -0.3 [95% CI, -0.3 to -0.2] images per 10 000 veterans). During the study period, 17 689 carotid procedures were identified, of which 3232 (18.3%) were preceded by carotid imaging ordered for low-value indications.

CONCLUSIONS AND RELEVANCE

These findings suggest that Choosing Wisely recommendations were not associated with a meaningful change in low-value carotid imaging in a national integrated health system. To reduce low-value testing and utilization cascades, interventions targeting ordering clinicians are needed to augment the impact of public awareness campaigns.

Older Adults' Perceptions of the Causes and Consequences of Healthcare Overuse: A Qualitative Study

BACKGROUND

Overuse of healthcare is pervasive in the United States, often exposing patients to harm with little likelihood of benefit. Older Americans are particularly vulnerable to overuse and impacted by it, yet it is unknown whether older patients perceive overuse as a consequential problem.

OBJECTIVE

To explore the experiences and perspectives of older adults with respect to healthcare overuse in order to develop a framework for understanding and reducing overuse in older adults.

DESIGN

Qualitative study using focus group methodology.

PARTICIPANTS

Five focus groups were held with people ≥65 years of age (N = 38) in four senior centers in Baltimore, Maryland, in 2016.

APPROACH

Transcripts were analyzed using qualitative content analysis to identify major themes.

KEY RESULTS

Of the 38 participants, 28 were women and 29 were African-American; 31 had at least a 12th grade education. While virtually all reported experience with what they perceived to have been healthcare overuse, some expressed concern that they had been denied appropriate care. They perceived overuse to have occurred when interventions were applied in the absence of symptoms (excluding cancer screening), did not improve symptoms, were discordant with their preferences, or were duplicative. Some defined overuse as interventions that were offered before less intensive options or too early in the course of disease. Suggested contributors to overuse were poor quality communication between patients and healthcare providers, and between different healthcare providers. Participants reported suffering from treatment effects, high costs, worry, and inconvenience from what they perceived to be overuse. They suggested that overuse may be reduced when the patient is involved in decision making and has a trusted primary care doctor.

CONCLUSIONS

The experience of older adults highlights potential sites of intervention to reduce healthcare overuse. Engaging patients in shared decision making and enhancing communication and knowledge transfer should be tested as interventions to reduce perceived overuse.

Recommendations for Low-Grade Carotid Stenosis Follow-up Based on a Single-Institution Database

OBJECTIVES

The purpose of this study was to determine the incidences and rates of progression of varying degrees of carotid stenosis that do not require intervention according to the Asymptomatic Carotid Atherosclerosis Study, the European Carotid Surgery Trial, and the North American Symptomatic Carotid Endarterectomy Trial, and from this information, to provide evidence-based recommendations for follow-up imaging.

METHODS

A retrospective review was performed of all carotid ultrasound examinations performed at a single institution from January 1995 through April 2015. Examinations following endarterectomy or stenting were excluded. Stenoses were classified by a modification of the criteria of Bluth et al (Radiographics 1988; 8:487-506). A Kaplan-Meier survival analysis was performed for stenosis progression and to provide information for follow-up recommendations.

RESULTS

Most of the carotid arteries (91.6%) reviewed for this study showed 1% to 39% stenosis. However, only 6.8% of carotid arteries with 1% to 39% stenosis progressed compared to 38.9% of carotid arteries with 40% to 59% stenosis. A table of evidence-based follow-up recommendations is provided for patients with varying levels of stenosis.

CONCLUSIONS

We provide evidence-based follow-up recommendations for patients who have low degrees of carotid stenosis. Different degrees of carotid stenosis progress at different rates and therefore should be followed at different intervals. Additionally, the most patients in our database showed 1% to 39% stenosis and did not have any follow-up imaging, suggesting that carotid ultrasound may not be overused for low degrees of stenosis.

2017 Update on Medical Overuse: A Systematic Review

Importance

Overuse of medical care is a well-recognized problem.

Objective

To identify and highlight original research articles published in 2016 that are most relevant to understanding medical overuse or strategies to reduce it.

Evidence Review

A structured review of English-language articles on PubMed published in 2016 coupled with examination of tables of contents of high-impact journals to identify articles related to medical overuse in adults. These articles were appraised for their importance to medicine.

Findings

This study considered 2252 articles, 1224 of which addressed medical overuse. Of these, 122 were deemed most relevant based on originality, methodologic quality, and number of patients potentially affected. The 10 most influential articles were selected by author consensus. Select findings from the studies include the lack of benefit of transesophageal echocardiography in the workup of cryptogenic stroke, increasing use of computed tomography in the emergency department from 2.2% to 9.4% from 2001 to 2010, and carotid ultrasonography and revascularization being performed for uncertain or inappropriate indications with 95% frequency. Likewise, services for which harms are likely to outweigh benefits include treatment for early-stage prostate cancer, which provides no mortality benefit but increases absolute risk of erectile dysfunction by 10% to 30%, oxygen for patients with moderate chronic obstructive pulmonary disease, surgery for meniscal tear with mechanical symptoms, and nutritional interventions for inpatients with malnutrition. This review highlights 2 methods for reducing overuse: clinician audit and feedback with peer comparison for antibiotic use (reduction in inappropriate antibiotic use from 20% to 4%) and a practical and sensible shared decision-making tool for low-risk chest pain (reduction in emergency department workup from 52% to 37%).

Conclusions and Relevance

The body of empirical work continues to expand related to medical services that are provided for inappropriate or uncertain indications. Engaging patients in conversations aimed at shared decision making and giving practitioners feedback about their performance relative to peers appear to be useful in reducing overuse.

Is atherosclerosis imaging the most sensitive way to assess patients' risk and the best way to conduct future drug trials? A pros-and-cons debate

Atherosclerosis imaging has been the focus of intense debate and research for several decades. Among its primary applications are risk stratification of asymptomatic individuals and follow-up of atherosclerosis progression under a variety of treatments designed to retard or regress the development of arterial disease. Although endorsed and supported by many, this approach has been fiercely opposed by several key opinion leaders over the years. Similarly, regulatory agencies have raised a number of objections to resist the approval of new drugs and devices based on surrogate imaging markers. However, there is a large body of evidence in the medical literature that shows that risk stratification is improved with implementation of atherosclerosis imaging. Additionally, numerous lipid-modifying agents have been tested as far as their ability to affect progression of atherosclerosis, and in many cases the information obtained with imaging was in line with the outcome of subsequent clinical trials. This pros-and-cons debate was staged to bring up in a fun and provoking way the main arguments in favour or against the application of atherosclerosis imaging in the main settings described above.

Evaluation and Management of Atherosclerotic Carotid Stenosis

Medical therapies for the prevention of stroke have advanced considerably in the past several years. There can also be a role for mechanical restoration of the lumen by endarterectomy or stenting in selected patients with high-grade atherosclerotic stenosis of the extracranial carotid artery. Endarterectomy is generally recommended for patients with high-grade symptomatic carotid stenosis. Stenting is considered an option for patients at high risk of complications with endarterectomy. Whether revascularization is better than contemporary medical therapy for asymptomatic extracranial carotid stenosis is a subject of several ongoing randomized clinical trials in the United States and internationally.