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D E Strandness

Publications and source records attributed to D E Strandness.

At least 37 records · Page 2Linked to original sources

A new pharmacological treatment for intermittent claudication: results of a randomized, multicenter trial.

BACKGROUND: Effective medication is limited for the relief of intermittent claudication, a common manifestation of arterial occlusive disease. Cilostazol is a potent inhibitor of platelet aggregation with vasodilation effects. OBJECTIVE: To evaluate the safety and efficacy of cilostazol for the treatment of intermittent claudication. METHODS: Thirty-seven outpatient vascular medicine clinics at regional tertiary and university hospitals in the United States participated in this multicenter, randomized, double-blind, placebo-controlled, parallel trial. Of the 663 screened volunteer patients with leg discomfort, a total of 516 men and women 40 years or older with a diagnosis of moderately severe chronic, stable, symptomatic intermittent claudication were randomized to receive cilostazol, 100 mg, cilostazol, 50 mg, or placebo twice a day orally for 24 weeks. Outcome measures included pain-free and maximal walking distances via treadmill testing, patient-based quality-of-life measures, global assessments by patient and physician, and cardiovascular morbidity and all-cause mortality survival analysis. RESULTS: The clinical and statistical superiority of active treatment over placebo was evident as early as week 4, with continued improvement at all subsequent time points. After 24 weeks, patients who received cilostazol, 100 mg, twice a day had a 51% geometric mean improvement in maximal walking distance (P<.001 vs placebo); those who received cilostazol, 50 mg, twice a day had a 38% geometric mean improvement in maximal walking distance (P<.001 vs placebo). These percentages translate into an arithmetic mean increase in distance walked, from 129.7 m at baseline to 258.8 m at week 24 for the cilostazol, 100 mg, group, and from 131.5 to 198.8 m for the cilostazol, 50 mg, group. Geometric mean change for pain-free walking distance increased by 59% (P<.001) and 48% (P<.001), respectively, in the cilostazol, 100 mg, and cilostazol, 50 mg, groups. These results were corroborated by the results of subjective quality-of-life assessments, functional status, and global evaluations. Headache, abnormal stool samples or diarrhea, dizziness, and palpitations were the most commonly reported potentially drug-related adverse events and were self-limited. A total of 75 patients (14.5%) withdrew because of any adverse event, which was equally distributed between all 3 treatment groups. Similarly, there were no differences between groups in the incidence of combined cardiovascular morbidity or all-cause mortality. CONCLUSION: Compared with placebo, long-term use of cilostazol, 100 mg or 50 mg, twice a day significantly improves walking distances in patients with intermittent claudication.

Adult↗

Blood pressure, antihypertensive medication, and atherosclerotic renal artery stenosis.

The relationship between atherosclerotic renal artery stenosis (ARAS) and blood pressure control remains poorly understood. Duplex ultrasonography is a noninvasive method for detecting and grading ARAS. The purpose of this study was to characterize the relationship between the degree of ARAS, levels of blood pressure, and control of blood pressure with antihypertensive medication. A cross-sectional analysis was performed on 139 patients with ARAS. All patients had at least one diseased renal artery by duplex ultrasound. Renal arteries were classified as normal, less than 60% stenosis, or 60% or greater (high-grade) stenosis. Data regarding blood pressure, coexisting risk factors, and medications were collected. The extent of ARAS was significantly associated with progressive elevation of the systolic blood pressure, whereas the diastolic component was elevated in the case of unilateral high-grade stenosis: no high-grade stenoses, 153 +/- 22/81 +/- 10 mm Hg; unilateral high-grade stenosis, 162 +/- 22/86 +/- 9 mm Hg; and bilateral high-grade stenoses, 174 +/- 27/82 +/- 9 mm Hg (P = 0.002 systolic; P = 0.02 diastolic). Eighty-two percent of the patients were taking known antihypertensive medications. Angiotensin-converting enzyme inhibitor (ACEI) usage versus nonusage was associated with a significantly lower systolic (157 +/- 27 v 169 +/- 22 mm Hg; P = 0.03) and diastolic (79 +/- 9 v 85 +/- 9 mm Hg; P = 0.001) blood pressure. The effect of ACEI usage was observed in patients with high-grade ARAS. None of the other classes of antihypertensive medications were associated with significantly lower blood pressure. In patients with ARAS, blood pressure levels were correlated with the severity of renal artery disease. Patients taking ACEIs had significantly lower blood pressures, and the effect of ACEI usage was strongest among patients with unilateral ARAS.

Aged↗

Venous thrombus stability during acute phase of therapy.

The purpose of this study was to use serial venous duplex scans to document the status of deep venous thrombi during the early phase of therapy for acute, deep-vein thrombosis (DVT). A total of 71 consecutive participants treated for a first episode of acute DVT were monitored for new venous thrombosis using serial venous duplex scans. An average of 4.6 duplex scans were performed per patient (range, three to seven) during the 3-week study period. The cumulative incidence of contiguous/non-contiguous extension of the DVT at 3 weeks was 26% (95% CI = 14% to 38%). Nine of the 15 (60%) occurrences were asymptomatic. None of the classical risk factors for DVT was significantly associated with the development of new thrombi. The fraction of time during which the level of anticoagulation was considered 'adequate' (international normalized ratio > or =2.0 and/or heparin concentration > or =0.2 IU/ml) was inversely associated with the risk of extension/new thrombi (p = 0.01, Cox proportional hazards analysis). It was concluded that: (1) the frequency of contiguous/non-contiguous extension of venous thrombosis detectable during the first 3 weeks of therapy was higher than previously reported; (2) the majority of the occurrences were asymptomatic; and (3) the risk of developing this complication was inversely associated with the level of anticoagulation achieved.

Adult↗

Cilostazol has beneficial effects in treatment of intermittent claudication: results from a multicenter, randomized, prospective, double-blind trial.

BACKGROUND: Cilostazol is a new phosphodiesterase inhibitor that suppresses platelet aggregation and also acts as a direct arterial vasodilator. This prospective, randomized, placebo-controlled, parallel-group clinical trial evaluated the efficacy of cilostazol for treatment of stable, moderately severe intermittent claudication. METHODS AND RESULTS: Study inclusion criteria included age > or =40 years, initial claudication distance (ICD) on treadmill (12.5% incline, 3.2 km/h) between 30 and 200 m, and confirmation of diagnosis of chronic lower-extremity arterial occlusive disease. After stabilization and single-blind placebo lead-in, 81 subjects (62 male, 19 female) from 3 centers were randomized unequally (2:1) to 12 weeks of treatment with cilostazol 100 mg PO BID or placebo. Primary outcome measures included ICD and maximum distance walked (absolute claudication distance, or ACD). Secondary outcome measures included ankle pressures, subjective assessments of benefit by patients and physicians, and safety. Treatment and control groups were similar with respect to age, severity of symptoms, ankle pressures, and smoking status. Statistical analyses used intention-to-treat analyses for each of 77 subjects who had > or =1 treadmill test after initiation of therapy. Comparisons between groups were based on logarithms of ratios of ICD and ACD changes from baseline using ANOVA test at last treatment visit. The estimated treatment effect showed a 35% increase in ICD (P<0.01) and a 41% increase in ACD (P<0.01). There was no significant change in resting or postexercise ankle/brachial indexes. Patients' and physicians' subjective assessments corroborated the measured improvements in walking performance observed in the cilostazol-treated group. CONCLUSIONS: Cilostazol improved walking distances, significantly increasing ICD and ACD. The data suggest cilostazol is safe and well tolerated for the treatment of intermittent claudication.

Adult↗

Carotid and lower extremity arterial disease in patients with renal artery atherosclerosis.

BACKGROUND: Atherosclerotic lesions of the carotid and lower extremity arteries may be associated with renal artery stenosis and influence the management of patients with renal artery disease. OBJECTIVE: To document the prevalence and clinical features of carotid and lower extremity arterial disease in patients with renal artery atherosclerosis. METHODS: An analysis of baseline data on 149 patients enrolled in a prospective natural history study of atherosclerotic renal artery stenosis. Patients with at least 1 abnormal renal artery by duplex scanning were eligible. Carotid artery disease was evaluated by duplex scanning, and ankle/brachial indices were used to assess the lower extremity arteries. Disease at each of the 3 arterial sites was classified as mild, moderate, or severe based on the extent of involvement on both sides. Serum urea nitrogen, creatinine, and lipid levels were also measured. RESULTS: Severe renal, carotid, or lower extremity arterial disease was present in 44%, 19%, and 21% of the patients, respectively. There was a trend for patients with increasing degrees of renal artery disease to have increasing degrees of carotid and lower extremity arterial disease. The prevalence of severe carotid artery disease increased from 7% in the mild renal artery group to 28% in the severe renal artery group. Clinical factors that were most predictive of severe disease were elevated apolipoprotein B levels for the renal arteries, high serum urea nitrogen or creatinine levels for the carotid arteries, and smoking for the lower extremity arteries. CONCLUSIONS: There was a strong association between severe renal artery atherosclerosis and severe carotid artery disease. Patients with renal artery disease also had a high prevalence of lower extremity arterial disease. In this patient population, screening for lower extremity arterial disease can be reserved for those with signs or symptoms of peripheral ischemia. Noninvasive carotid screening is justified in patients with renal artery disease to detect asymptomatic lesions that require either immediate surgical treatment or serial follow-up for disease progression.

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Clinical evidence of contralateral renal parenchymal injury in patients with unilateral atherosclerotic renal artery stenosis.

It has been postulated that the kidney contralateral to a significant renal artery stenosis may be at risk for accelerated arteriolar nephrosclerosis. Duplex ultrasound is capable of detecting and classifying renal artery stenosis and examining parenchymal flow. Renal flow patterns are a reflection of resistance, which increases with parenchymal pathology. One-hundred fifty-one patients with atherosclerotic renal artery stenosis (ARAS) were prospectively studied with duplex ultrasonography. Renal arteries were classified as normal, <60% stenosis, > or =60% stenosis, or occluded. The renal artery end-diastolic ratio (EDR) (end-diastolic velocity/peak systolic velocity) was measured. EDR decreases as resistance to flow increases. There were 81 patients with a unilateral > or =60% ARAS. The EDR was significantly lower in the kidney contralateral to the > or =60% ARAS (0.27 +/- 0.08 versus 0.30 +/- 0.08; p = 0.001, paired t-test). The absolute difference in EDR was even more pronounced in the subgroup of 15 diabetic patients with a > or =60% ARAS (0.22 +/- 0.08 versus 0.27 +/- 0.08; p = 0.004). This study offers clinical evidence that a unilateral hemodynamically significant ARAS is associated with the development of arteriolar nephrosclerosis in the contralateral kidney. These results have important implications on blood pressure control, renal function, and response to renal revascularization in this patient population.

Aged↗

Vein graft surveillance with scanhead tracking duplex ultrasound imaging: a preliminary report.

A severe arterial occlusion in the leg usually is bypassed by implanting a saphenous vein harvested from the limb. Once implanted, the vein functions well but over time may develop stenoses that may lead to occlusion. In order to detect and correct the stenoses that may lead to graft failure, frequent surveillance of the vein graft is required. A new ultrasound imaging method was developed to display the panoramic view of the vein graft in combination with its blood flow velocity waveform for surveillance. The panoramic view is the projection (ray-casting) image of multiple B-mode images with sequential longitudinal view of the vein graft. The velocity waveform also is recorded along the vessel with pulsed Doppler ultrasound. The acquired images and waveforms from the ultrasound scanner are registered individually in three-dimensional space with an electromagnet-based position and orientation sensor located on the scanhead. A prominent point on the scar from the surgery is used as the fiducial mark for spatial registration, so that the same lesion in the vein graft can be tracked automatically at each visit for retrospective study.

Arterial Occlusive Diseases↗

Determinants of chronic venous disease after acute deep venous thrombosis.

PURPOSE: The purpose of this investigation was to evaluate the relationship between the presenting features of an acute deep venous thrombosis (DVT), the subsequent natural history of the thrombus, and the ultimate outcome as defined according to the Society for Vascular Surgery and the North American Chapter of the International Society for Cardiovascular Surgery reporting standards in venous disease. METHODS: Patients with an acute DVT were followed with serial clinical and ultrasound examinations. Thrombus extent within 7 venous segments was scored retrospectively according to the reporting standards (scores ranged from 0 to 3), and segmental reflux was scored as present (1) or not present (0). The initial and final thrombus scores, the rates of recanalization and rethrombosis, and the total reflux scores were then calculated from these grading scales and related to ultimate chronic venous disease (CVD) classification. RESULTS: Sixty-eight patients with an acute DVT in 73 limbs were followed for 18 to 110 months (mean, 55 +/- 26 months). At the completion of the follow-up period, 20 extremities (27%) were asymptomatic (class 0), 13 (18%) had pain or prominent superficial veins (class 1), 25 (34%) had manifested edema (class 3), 13 (18%) had developed hyperpigmentation (class 4), and 2 (3%) had developed ulceration (class 5). In a univariate analysis, CVD classification was correlated with the reflux score (P =.003) but not with the initial or final thrombus score or with the rate of recanalization or rethrombosis. In a multivariate model of features documented at presentation, only the tibial thrombosis score was a significant predictor of CVD classification (R2 =.06). Outcome was better predicted (R2 =.29) with a model that included variables defined during follow-up the final reflux score, the final popliteal score, and the rate of recanalization. CONCLUSION: The ability to predict the severity of CVD after an acute DVT is currently limited, although the natural history appears more important than the presenting features of the event. The extent of reflux, the presence of persistent popliteal obstruction, and the rate of recanalization are related to ultimate CVD classification, but other determinants remain to be identified.

Acute Disease↗

Carotid artery stenosis--where do we go from here?

Carotid artery stenosis is an important risk factor for stroke. The European Carotid Surgery Trial (ECST) and the North American Symptomatic Carotid Endarterectomy Trial (NASCET) have demonstrated that the risk of stroke is reduced by surgery in patients with high grade stenosis (70-99%). However, because the two trials used different methods to measure stenosis, the results are not comparable and the level of stenosis which is associated with increased risk of stroke cannot be strictly defined. The benefit of surgery in asymptomatic patients is more controversial. Some studies indicate that surgery reduces the risk of stroke only in patients with ?80% stenosis and others have shown benefits for patients with ?60% stenosis. Overall, the benefits of surgery in asymptomatic patients are more difficult to define. Carotid lesion morphology also plays an important role in determining the risk of stroke; plaques which are ulcerated and echolucent are associated with a higher risk of stroke. Arteriography has been long regarded as the gold standard diagnostic tool for carotid stenosis. It is a costly and invasive technique with potentially serious complications. The results of arteriography have not been standardised which makes comparison of results from different laboratories difficult. Duplex ultrasound is inexpensive, non-invasive and can provide functional and anatomical information about vessel stenosis and plaque morphology. The use of echo-enhancing agents helps to reduce operator variability, improves ultrasound images and can help to distinguish between pseudo and true occlusions, to identify patients who will benefit most from surgery. The echo-enhancing agent Levovist(R) is safe, produces consistent results and can enhance images throughout the blood pool. Clinical studies with Levovist(R) have shown it to be safe and highly effective in improving diagnostic confidence in patients with carotid artery stenosis. The number of non-diagnostic scans is reduced markedly when Levovist(R) is used to enhance ultrasound images.

Carotid Stenosis↗

Risk of atrophy in kidneys with atherosclerotic renal artery stenosis.

The goal of this study was to determine the incidence of and risk factors for renal atrophy among kidneys with atherosclerotic renal artery stenosis (ARAS). Participants with at least one ARAS were followed prospectively with duplex scans performed every six months. Renal atrophy was defined as a reduction in renal length of greater than 1 cm. A total of 204 kidneys in 122 subjects were followed for a mean of 33 months. The two-year cumulative incidence (CI) of renal atrophy was 5.5%, 11.7%, and 20.8% in kidneys with a baseline renal artery disease classification of normal, <60% stenosis, and > or = 60% stenosis, respectively (P = 0.009, log rank test). Other baseline factors associated with a high risk of renal atrophy included a systolic blood pressure > 180 mm Hg (2-year CL = 35%, P = 0.01), a renal artery peak systolic velocity > 400 cm/second (2-year CI = 32%, P = 0.02), and a renal cortical end diastolic velocity < or = 5 cm/second (2-year CI = 29%, P = 0.046). The number of kidneys demonstrating atrophy per participant was correlated with elevations in the serum creatinine concentration (P = 0.03). In patients with ARAS, there is a significant risk of renal atrophy among kidneys exposed to elevated systolic blood pressure and among those with high-grade ARAS and low renal cortical blood flow velocity as assessed by renal duplex scanning. The occurrence of renal atrophy is well-correlated with changes in the serum creatinine concentration.

Aged↗

Intragastric distribution and gastric emptying assessed by three-dimensional ultrasonography.

BACKGROUND & AIMS: Three-dimensional (3D) ultrasound imaging of the total stomach volume has not yet been achieved. The aim of this study was to investigate whether a magnetic position sensor system for acquisition of 3D ultrasonograms could be used to determine gastric emptying rates and intragastric distribution. METHODS: A system for position and orientation measurement was interfaced to an ultrasound scanner. In vitro accuracy was evaluated by scanning a porcine stomach. Fourteen volunteers, with a median age of 35 years, were scanned fasting and postcibally by two-dimensional (2D) and 3D ultrasound after ingesting a 500-mL soup meal. RESULTS: This 3D system yielded a strong correlation (r = 0.997) between true and estimated volumes in vitro. The limits of agreement were -9.1:70.1 mL in the volume range 1200-1900 mL. The intersubject variability of the total gastric volumes ranged from 12.5% to 46.0%, less than for antral area variability. The average half-emptying time was 22.1 +/- 3.8 minutes. Intragastric distribution of the meal, expressed as proximal distal volume, varied on average from 3.6 +/- 2.1 (5 minutes postpradially) to 2.7 +/- 1.9 (30 minutes postprandially). CONCLUSIONS: This 3D ultrasound system using magnetic scanhead tracking showed excellent in vitro accuracy, calculated gastric emptying rates more precisely than by 2D ultrasound, and enabled estimation of intragastric distribution of a soup meal.

Adult↗

Early outcome after isolated calf vein thrombosis.

PURPOSE: The clinical significance of isolated calf vein thrombosis (CVT), particularly with respect to development of the postthrombotic syndrome, remains controversial. The purpose of this study was to define the early natural history of CVT in relation to persistent lower extremity symptoms, propagation, recanalization, and the development of valvular incompetence. METHODS: Over a 116-month period, 499 patients with acute deep venous thrombosis (DVT) were referred to our research laboratory, of whom 58 (12%) had thrombosis confined to the calf veins of at least one extremity. The lower extremities of 268 patients (29 with isolated CVT) were followed-up clinically and with duplex ultrasonography at intervals of 1 day, 7 days, 1 month, every 3 months for the first year, and yearly thereafter. RESULTS: Seventy percent of extremities with CVT were symptomatic at presentation. Although the prevalence of clinical signs and symptoms decreased to 29% by 1 month, 23% of patients had persistent pain, edema, or both at 12 months. In contrast, 9% of uninvolved extremities contralateral to a CVT and 54% of extremities with proximal DVT remained symptomatic at 1 year (p = 0.004). Recanalization proceeded rapidly such that the mean thrombus load was reduced by 50% at 1 month and to zero at 1 year. The prevalence of valvular incompetence progressively increased such that reflux was present in 24% of extremities at 1 year. Although its investigation was not a primary goal of this study, pulmonary embolism was diagnosed at presentation and during follow-up in 11% and 3% of patients, respectively. CONCLUSIONS: The natural history of CVT is complicated by persistent symptoms and the development of valvular incompetence in approximately one-quarter of patients. This potential for persistent lower extremity symptoms should be considered in evaluating the clinical relevance of isolated calf vein DVT.

Acute Disease↗

Detection of "functional" valves in reversed saphenous vein bypass grafts: identification with duplex ultrasonography.

PURPOSE: Although venous valve lesions have been cited as a mechanism of graft failure, the fate of venous valves in reversed saphenous vein (RSV) bypass grafts is unclear. The basis for this uncertainty is the difficulty in postoperative identification and follow-up of valve sites and the infrequent pathologic submission of vein graft lesions. This report describes the features of "functional" valves (FV) visualized in RSV grafts by ultrasonic duplex scanning. METHODS: Sixty-six RSV infrainguinal vein grafts were prospectively studied with duplex ultrasonography from January 1992 to December 1995. Grafts were studied at 1, 2, 3, 4, 6, 9, 12, 18, and 24 months, then annually. FV identification was based on a characteristic ultrasound Doppler waveform and color flow pattern and visualization of the leaflets by B-mode imaging. The waveform consists of end-systolic valve closure followed by variable degrees of reflux. Immediate postoperative reactive hyperemia precludes detection, because flow reversal in the graft is needed for identification. RESULTS: Since August 1994, 14 FV have been identified in 11 (17%) of 66 RSV grafts. The mean time to FV recognition after implantation was 10 months (range, 1 to 52 months), and the average follow-up was 15 months. One valve was completely competent. Seven (50%) of the FV were associated with the development of a < 50% diameter reducing stenosis by Doppler velocity criteria. None of the FV has required intervention. CONCLUSIONS: "Functional" vein valves in RSV grafts are common and can be identified by ultrasonic duplex imaging. Awareness of the characteristics of FV during routine duplex graft surveillance will undoubtedly increase detection. The variable time course to identification of FV and duration of "function" warrants continued follow-up to determine the relationship of these valves to the development of stenotic lesions and graft failure.

Aged↗

Results of percutaneous transluminal angioplasty for atherosclerotic renal artery stenosis: a follow-up study with duplex ultrasonography.

PURPOSE: The short and long-term anatomic results of percutaneous transluminal renal angioplasty (PTRA) in the treatment of atherosclerotic renovascular disease have been poorly documented because of a lack of follow-up arteriography. The purpose of this study was to evaluate the anatomic results of PTRA with serial duplex examinations. METHODS: The records of 41 patients who underwent 52 primary PTRA procedures and had subsequent duplex follow-up of at least 6 months were reviewed. After PTRA, renal arteries were classified as normal, < 60% stenosis, > or = 60% stenosis, or occluded on the basis of previously validated duplex criteria. RESULTS: The study group included 26 men and 15 women with a mean age of 65 years, who were observed for a mean interval of 34 months. Endovascular stents were placed in 12 of the 52 arteries. The initial post-PTRA renal artery stenosis classification (based on arteriography or duplex scan) was normal in 23, < 60% in 19, and > or = 60% in 10. The cumulative incidence of restenosis from normal to > or = 60% was 13% at 1 year and 19% at 2 years. The cumulative incidence of restenosis from < 60% to > or = 60% was 44% at 1 year and 55% at 2 years. The cumulative incidence of progression from > or = 60% to occlusion was 10% at 2 years. Although 83% of the 12 stented arteries and only 33% of the 40 nonstented arteries were normal immediately after PTRA, after 1 year the stented renal arteries showed a 44% restenosis rate, whereas the nonstented renal arteries showed a 18% restenosis rate (p = 0.087). CONCLUSIONS: Restenosis after PTRA for atherosclerotic disease is relatively common and correlates with the initial anatomic result. Although PTRA with stent placement yields superior immediate technical results, the high early restenosis rate is disturbing.

Aged↗

Carotid plaque morphology and clinical events.

BACKGROUND AND PURPOSE: Studies have suggested that B-mode ultrasonography can be used to determine carotid plaque composition and that specific plaque characteristics are associated with a worse clinical outcome. However, histological studies examining the relationship between carotid plaque morphology and clinical outcome have reported conflicting findings. Furthermore, few investigators have described plaque morphology in quantifiable terms. This study examines the association between the volume of carotid plaque constituents and preoperative ischemic neurological symptoms. Constituents examined were chosen based on their potential for identification by current diagnostic imaging modalities such as ultrasound or MRI. METHODS: Atherosclerotic plaques from 43 patients undergoing carotid endarterectomy were examined histologically, with sections obtained every 0.5 to 1 mm. The lesions were examined for the presence and quantity of fibrous intimal tissue, intraplaque hemorrhage, lipid core, necrotic plaque core, and calcification. The quantity of each constituent was compared in plaques removed from symptomatic patients with those excised from asymptomatic individuals. Differences were analyzed with a Kolmogorov-Smirnov statistic. RESULTS: There was no difference between plaques removed from asymptomatic and symptomatic patients with regard to the presence and volume of fibrous intimal tissue, intraplaque hemorrhage, the lipid core, the necrotic core, or calcification. CONCLUSIONS: In patients with highly stenotic carotid lesions who are undergoing carotid endarterectomy, gross plaque composition is similar regardless of preoperative symptom status. Given this similarity, it is unlikely that differences in the volume of intraplaque hemorrhage, lipid core, necrotic core, or calcification in atherosclerotic carotid plaques explain their embolic history.

Aged↗