Carotid duplex criteria: What have we learned in 40 years?

Before the development of the first prototype duplex ultrasound scanner at the University of Washington in the late 1970s, the only noninvasive tests available for extracranial carotid artery disease were indirect methods, such as the periorbital Doppler examination and oculoplethysmography. The duplex scanner combined real-time two-dimensional B-mode imaging and pulsed-Doppler flow detection in a single instrument and provided Doppler spectral waveforms from discrete sites within the vessel lumen. Spectral waveforms allowed characterization of the flow patterns and velocity changes associated with normal and diseased arteries. In a series of validation studies, Dr. D. Eugene Strandness, Jr. and colleagues compared various spectral waveform parameters obtained from internal carotid arteries to independently read carotid arteriograms and established quantitative threshold criteria for classification of carotid artery disease. These criteria were based on peak systolic velocity and end-diastolic velocity, as well as features such as spectral broadening and flow separation. Internal carotid arteries were classified as normal, 1% to 15% diameter reduction, 16% to 49% diameter reduction, 50% to 79% diameter reduction, 80% to 99% diameter reduction, and occluded. Since the 1980s, the University of Washington carotid duplex criteria have been widely used and modified in vascular laboratories throughout the world. Additional clinically relevant criteria have also been developed, such as a threshold for the 70% to 99% North American Symptomatic Carotid Endarterectomy Trial (NASCET) stenosis. Validation of carotid criteria has always depended on comparing spectral waveform parameters to the "gold standard" of contrast arteriography. However, experience has shown that the relationship between velocity and arteriographic stenosis is subject to significant variability. Based on these observations, standardization of carotid duplex criteria should lead to more consistent reporting among vascular laboratories, but it is unlikely to result in improved correlation with arteriography.

History of carotid artery stenting.

The history of carotid artery stenting (CAS) was made by brave men and women who believed in a less invasive treatment modality than carotid endarterectomy (CEA) to treat carotid stenosis despite the risk--which was obviously present also with surgery--to cause a stroke, the very event that the procedure aimed to prevent. The bulky equipment, the lack of knowledge about the appropriate antithrombotic regimen, and the impossibility at early stage to influence distal embolization added to the pressure on the investigators. At times, the confrontation with the surgical community has been hard. The technique evolved with the inputs of multiple disciplines on both sides of the Atlantic including radiology, cardiology, neuroradiology and vascular surgery. Major breakthrough included the use of dual antiplatelet therapy, of self-expanding stents and of emboli protection devices. Unfortunately, randomized investigations against surgery started too early, in a phase in which the cas technique was not yet mature and the investigators lacked the necessary experience in terms of catheter skills and appropriate patient selection.

Stratifying risk: asymptomatic carotid disease / Estratificação do risco na doença carotídea assintomática

Stroke generates significant healthcare expenses and it is also a social and economic burden. The carotid artery atherosclerotic plaque instability is responsible for a third of all embolic strokes. The degree of stenosis has been deliberately used to justify carotid artery interventions in thousands of patients worldwide. However, the annual risk of stroke in asymptomatic carotid artery disease is low. Plaque morphology and its kinetics have gained ground to explain cerebrovascular and retinal embolic events. This review provides the readers with an insightful and critical analysis of the risk stratification of asymptomatic carotid artery disease in order to assist in selecting potential candidates for a carotid intervention.

O acidente vascular encefálico gera custos significativos na área da saúde e representa um problema social e econômico. A instabilidade da placa carotídea aterosclerótica é responsável por um terço dos acidentes vasculares encefálicos embólicos. O grau de estenose tem sido usado para justificar, deliberadamente, intervenções carotídeas em milhares de pacientes no mundo todo. No entanto, o risco anual de acidente vascular encefálico em doença carotídea assintomática é baixo. A morfologia da placa e sua mobilidade têm ganhado importância na elucidação dos eventos embólicos cerebrovasculares e retinais. Esta revisão proporciona aos leitores uma análise crítica e inteligente da estratificação de risco da doença carotídea assintomática com o intuito de auxiliar na seleção de potenciais candidatos à intervenção carotídea.

Discovery of cerebrovascular moyamoya disease: research during the late 1950s and early 1960s.

Carotid angiography employing a percutaneous technique, which was devised by Shimizu in 1937, was popularized among neurosurgeons in Japan soon after World War II. This opened up an opportunity for them to encounter and investigate moyamoya disease, since this disease is more common among Asians. They began to publish their findings on what is currently called moyamoya disease in the Japanese literature during the late 1950s and early 1960s. It was only in the late 1960s, however, that their studies were published in the English literature. The early history of the discovery of this disease is therefore not widely known. In 1957, Takeuchi and Shimizu reported a case of an unknown disease characterized by hypoplasia of the internal carotid arteries. In 1964, Moriyasu and his colleagues published a report of four child cases with occlusion of the internal carotid artery. They also published in the same year a report of five adult cases with occlusion of the internal carotid arteries for an unknown reason, placing special emphasis on an abnormal vascular network located at the base of the brain, which is presently termed moyamoya vessels. In 1968 and 1969, Kudo, Nishimoto, and Takeuchi, as well as Suzuki and Takaku, published their studies in the English literature, which contributed greatly to the recognition of moyamoya disease throughout the world. Takeuchi and Shimizu, and Moriyasu also deserve credit as the researchers who reported the crucial features of moyamoya disease for the first time.

Contemporary relevancy of carotid-subclavian bypass defined by an experience spanning five decades.

BACKGROUND: The contemporary impact of and indications for carotid-subclavian bypass (CSB) are essential considerations in decision making for brachiocephalic reconstruction. METHODS: We analyzed operative outcomes, long-term graft patency, and the extended epidemiological impact of the primary disease process in 287 consecutive patients (mean age, 60.6 years; 43.2% male) who received CSB for symptomatic brachiocephalic disease. RESULTS: Technical success was achieved in each patient. Operative mortality was 1.0% (3/287) and total (ipsilateral [1.4%, 4/287] plus contralateral [0.7%, 2/287]) stroke rate was 2.1% (6/287). Primary patency rates at 5, 10, and 15 years were 94.2 ± 1.9%, 88.6 ± 3.2%, and 86.5 ± 3.8%, respectively. Kaplan-Meier freedom from specific events at 15 years was as follows: restenosis, 86.5 ± 3.8%; death, 67.5 ± 5.2%; coronary revascularization, 59.6 ± 6.3%; myocardial infarction, 82.8 ± 3.9%; stroke, 85.6 ± 4.9%; other vascular procedure, 60.0 ± 5.5%; adverse cardiac outcome (death, myocardial infarction, or coronary revascularization), 44.5 ± 5.5%; and adverse vascular outcome (restenosis, stroke, or other vascular procedure), 48.7 ± 5.3%. CONCLUSIONS: CSB produces excellent long-term patency and extended symptom relief, with acceptably low operative morbidity and mortality. Despite the durability and success of CSB, the primary disease process has an adverse impact on long-term prognosis and significantly influences decision making with regard to management. The proven durability may offer extended symptom relief to the relatively younger patient, a survival advantage associated with preservation of internal mammary artery perfusion in patients at risk for myocardial revascularization, optimal durability in patients requiring a concomitant open procedure, and preservation of limb function in patients who require aortic endovascular graft placement.

Perspective: carotid stenting and the history of disruptive technology in vascular surgery.

This article defines disruptive technology and discusses such technologies in Vascular Surgery. It considers the question: Is carotid artery stenting (CAS) a disruptive technology? Although CAS will impact positively on the treatment of carotid bifurcation disease, it will probably never displace carotid endarterectomy in the majority of patients. The precise role of CAS remains to be determined.

Dr C. Miller Fisher and the history of carotid artery disease.

BACKGROUND AND PURPOSE: Our aim was to analyze the role that C. Miller Fisher (C.M.F.) had in promoting an understanding of carotid artery disease (CAD). Although Chiari in 1905 and later Hunt, Moniz, and Hultquist, among others, described the association of CAD and stroke, this received little attention until C.M.F. published his clinicoanatomic correlations in "Occlusion of the Carotid Arteries." Until then, some 55% of strokes were attributed to "vasospasm." METHODS: We analyzed articles ("Occlusion of the Internal Carotid Artery," 1951; "Occlusion of the Carotid Arteries," 1954; "Transient Monocular Blindness Associated with Hemiplegia," 1952; "The Microembolic Theory of Transient Ischemic Attacks," 1976; "A Clinico-pathologic Study of Carotid Endarterectomy Plaques," 1986) and conducted personal interviews with C.M.F. RESULTS: During the 1950s, C.M.F. described the clinical implications of transient ischemic attacks and their relationship to CAD and stroke. The last sentence in the 1951 article read: "Unexplained cerebral embolism may arise from thrombotic material lying in the carotid sinus." In the same article he also wrote that "it is even conceivable that some day vascular surgery will find a way to by-pass the occluded portion of the artery during the period of ominous fleeting symptoms," heralding the future surgical treatment of carotid artery disease. C.M.F. called attention to the commonness of carotid disease, described transient monocular blindness, and studied the relationship between plaque pathology and clinical findings. CONCLUSIONS: C.M.F.'s clinicopathologic observations were a major factor in promoting recognition of the clinical features, stroke risk, and treatment of CAD.