Why do guidelines recommend screening for abdominal aortic aneurysms, but not for asymptomatic carotid stenosis? A plea for a randomized controlled trial.

BACKGROUND: Current guidelines do not recommend screening for asymptomatic carotid artery stenosis (AsxCS). The rationale behind this recommendation is that detection of AsxCS may lead to an unnecessary carotid intervention. In contrast, screening for abdominal aortic aneurysms is strongly recommended. METHODS: A critical analysis of the literature was performed to evaluate the implications of detecting AsxCS. RESULTS: Patients with AsxCS are at high risk for future stroke, myocardial infarction and vascular death. Population-wide screening for AsxCS should not be recommended. Additionally, screening of high-risk individuals for AsxCS with the purpose of identifying candidates for a carotid intervention is inappropriate. Instead, selective screening for AsxCS should be considered and should be viewed as an opportunity to identify individuals at high risk for atherosclerotic cardiovascular disease and future cardiovascular events for the timely initiation of intensive medical therapy and risk factor modification. CONCLUSIONS: Although mass screening should not be recommended, there are several arguments suggesting that selective screening for AsxCS should be considered. The rationale supporting such selective screening is to optimize risk factor control and to initiate intensive medical therapy for prevention of future cardiovascular events, rather than to identify candidates for an intervention.

Comparison of Recent Practice Guidelines for the Management of Patients With Asymptomatic Carotid Stenosis.

Despite the publication of several national/international guidelines, the optimal management of patients with asymptomatic carotid stenosis (AsxCS) remains controversial. This article compares 3 recently released guidelines (the 2020 German-Austrian, the 2021 European Stroke Organization [ESO], and the 2021 Society for Vascular Surgery [SVS] guidelines) vs the 2017 European Society for Vascular Surgery (ESVS) guidelines regarding the optimal management of AsxCS patients.The 2017 ESVS guidelines defined specific imaging/clinical parameters that may identify patient subgroups at high future stroke risk and recommended that carotid endarterectomy (CEA) should or carotid artery stenting (CAS) may be considered for these individuals. The 2020 German-Austrian guidelines provided similar recommendations with the 2017 ESVS Guidelines. The 2021 ESO Guidelines also recommended CEA for AsxCS patients at high risk for stroke on best medical treatment (BMT), but recommended against routine use of CAS in these patients. Finally, the SVS guidelines provided a strong recommendation for CEA+BMT vs BMT alone for low-surgical risk patients with >70% AsxCS. Thus, the ESVS, German-Austrian, and ESO guidelines concurred that all AsxCS patients should receive risk factor modification and BMT, but CEA should or CAS may also be considered for certain AsxCS patient subgroups at high risk for future ipsilateral ischemic stroke.

The quick carotid scan for prevention of strokes due to carotid artery disease.

There are approximately 800,000 strokes in the United States (U.S.) annually. This number has remained the same for decades despite efforts at prevention. The Center for Disease Control (CDC) estimates that 80% of strokes could be prevented. A prime reason for failure of prevention is that the three immediate modifiable causes of strokes, carotid artery disease (CAD), atrial fibrillation (AFib), and hypertension (HTN) are asymptomatic in 80% of cases prior to the stroke. Strokes occur predominantly in seniors and the only possible means of reducing strokes on a large scale is to screen seniors for the asymptomatic disease so that it can be preemptively managed. We present a quick, accurate and cost-effective method of screening the senior population for asymptomatic carotid disease. The technique is a quick carotid scan (QCS). The QCS is a 1-minute long, image only, rapid, color flow ultrasound scan of the cervical carotid arteries that had a sensitivity of 97% when evaluated at New York University (NYU). Once identified by the QCS the approximately 8% of those screened found to have a positive QCS can then be referred for a full carotid duplex ultrasound (DUS). Those patients with a positive DUS can then be referred for further evaluation and appropriate stroke prevention management. The use of a full carotid DUS for screening widely for carotid disease is too time consuming and too costly. Approximately 160,000 or nearly 20% of the 800,000 strokes that occur annually in the U.S. are due to CAD that could in large part be prevented by screening the senior population with the QCS, finding those with CAD, evaluating them, and preemptively managing them prior to the occurrence of the stroke.

Rapid high-volume population screening for three major risk factors of future stroke: phase I results.

Three proximate risk factors for stroke are carotid stenosis, atrial fibrillation, and hypertension. Phase I of this prospective study was designed to establish the prevalence of these conditions among a population of health maintenance organization beneficiaries by using a rapid screening protocol in order to risk-stratify patients for appropriate management and subsequent cohort analysis. Patients at a tertiary care medical center were screened for stroke risk by using directed history, a 3-minute carotid "quick-scan'' protocol, an EKG lead II rhythm strip, and bilateral arm blood pressures. Patients with any abnormal result underwent specific diagnostic consultation with vascular surgery, cardiology, or primary care. These evaluations included formal carotid duplex ultrasound, 12-lead EKG +/- Holter monitor, and 5-day blood pressure check. Patients were then stratified into risk cohorts for appropriate management and future analysis of stroke incidence and outcomes. In 8 hours on a single day in October 2002, 294 patients (mean age 69) were screened. Combining history with results of screening and diagnostic tests, the overall prevalence of carotid stenosis was 6% (n = 17/294), atrial fibrillation 7% (n = 21/294), and severe hypertension 5% (n = 16/294). Fifty-nine patients (20%) screened positive for carotid stenosis by "quick-scan,'' and 29% (n = 17/59) of these had confirmed stenosis (>50%) in 1 or both arteries by formal duplex. The prevalence of confirmed carotid stenosis was 37% among those screening positive for 1 artery (odds ratio [OR] 14.6; p<0.001) and 75% among those screening positive for both (OR 74.7; p<0.001). Significant independent predictors of carotid stenosis by multivariate analysis included coronary artery disease or myocardial infarction, smoking, stroke or transient ischemic attack, male gender, and white race (all p<0.05). The prevalence of confirmed stenosis was 10% with any 3 predictors alone (OR 2.5; p<0.05), 31% with any 4 (OR 21.2; p<0.001), and 50% with all 5 (OR 46.5; p<0.001). Thirty-three patients (11%) were found to have a previously unidentified and untreated arrhythmia, and 12% (n = 4/33) of these had confirmed new atrial fibrillation; 158 patients (54%) had moderate hypertension and 16 (5%) had severe hypertension (>180/100). Overall, 82% (n = 242/294) of patients screened required additional diagnostic tests. Based on these results, 11% (n = 31/294) of patients were stratified as high risk, 64% (n = 188/294) as moderate risk, and 25% (n = 75/294) as low risk for future stroke. Rapid and efficient screening of a large population for stroke risk factors is feasible. The prevalence of undiagnosed, unsurveilled, and untreated carotid stenosis, atrial fibrillation, and severe hypertension is significant, as 75% of patients screened had 1 or more confirmed major risk factors for stroke. Phase II of this study will investigate the degree of stroke risk reduction possible with a multidisciplinary approach to early identification and aggressive treatment of these risks.

Noninvasive vascular testing--a 35-year reflection.

Noninvasive vascular testing has made a major contribution to the care of vascular surgery patients. This article a reflection on a 35-year corroborative association with Doctor Norman Rich, during which many of the advances in noninvasive vascular testing have been witnessed and effected. I served my vascular surgery fellowship under Doctor Rich in 1967-68 at Walter Reed Army Hospital. The only noninvasive vascular equipment then was a pencil probe Doppler. The value of the Doppler in the management of peripheral vascular disease that year and in determining limb viability in combat surgery in Vietnam the following year was established, and both experiences were published. Later, Doctor Rich established the annual Military Vascular Surgery Meeting and was appointed as the first Chair of the Department of Surgery at the Uniformed Services University for Health Sciences (USU). I entered private practice in Central California in 1976, and ultrasonic imaging was developed which allowed noninvasive examination of the carotid arteries. I then developed a protocol to screen for the three silent, immediate causes of stroke, employing a "a quick carotid scan" for carotid artery disease, a lead II rhythm strip for atrial fibrillation, and blood pressure determination for hypertension so that these common causes of strokes could be recognized and treated, and potentially prevent the majority of strokes. My association with USU, Doctor Rich, and others involved proved instrumental in initiating implementation of stroke prevention screening. The structure established at USU provides a means of establishing the protocol nationally. Noninvasive vascular testing is an addition to Medical Science that has led to significant improvements in individual patient care and that has the potential of allowing a major reduction in death and disability from stroke and other vascular diseases. Throughout a 35-year collaborative association with Doctor Norman M. Rich, I have witnessed and developed many of these advances. These contributions to noninvasive vascular testing reflect the value of our collaboration.

Development and implementation of a rapid, accurate, and cost-effective protocol for national stroke prevention screening.

BACKGROUND: Three medical conditions--cervical carotid artery disease, atrial fibrillation, and hypertension--cause the majority of strokes. Discovering these silent, immediate causes of stroke through screening, so they can be treated before stroke occurs, can potentially prevent strokes on an epidemiologic scale. METHODS: A rapid, accurate, and cost-effective stroke prevention screening (SPS) protocol was developed. RESULTS: The SPS protocol was used to screen 6,073 seniors residing in the central valley of California, at Madigan Army Medical Center, at New York University, and by the American Vascular Association at 68 leading institutions. The screening was estimated to have prevented 30 strokes and to have saved the health care system >$2 million. CONCLUSIONS: Implementation of a national SPS for seniors can discover the silent, immediate causes of strokes so they can be managed before stroke occurs and can potentially prevent the majority of strokes that we are currently not preventing.