Biomedical subjects

George S Lavenson

Publications and source records attributed to George S Lavenson.

3 recordsLinked to original sources

PubMed2005

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.

History, 20th Century↗

PubMed2004

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.

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PubMedDate not supplied

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.

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