Operative management of chronic mesenteric ischemia.
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Blood Vessel Prosthesis Implantation↗
Biomedical subjects
A Kazmers
Publications and source records attributed to A Kazmers.
Effect of the Asymptomatic Carotid Atherosclerosis Study on carotid endarterectomy in Veterans Affairs medical centers.
OBJECTIVE: To examine the effect of the Asymptomatic Carotid Atherosclerosis Study on the volume of carotid endarterectomies (CEAs) performed in Veterans Affairs medical centers. DESIGN: The data were retrospectively extracted from the Veterans Affairs Patient Treatment File for all patients undergoing CEA using the International Classification of Diseases, Ninth Revision, Clinical Modification procedural code 38.12. Data were classified into patient management categories to identify complications and to quantify the severity of illnesses and comorbidities. SETTING: All 172 US Veterans Affairs medical centers. PATIENTS: Veterans undergoing CEA during fiscal years 1993 through 1995. MAIN OUTCOME MEASURES: Procedural volume, mortality, and morbidity. RESULTS: There was a 43.4% increase in the volume of CEAs performed in fiscal year 1995 despite a 4.6% decrease in the served inpatients and an 8.8% decrease in the inpatient surgical procedures. The monthly volume of CEAs increased (P < .001, r2 = 0.78) at the onset of the fiscal year (October 1994) immediately after the Asymptomatic Carotid Atherosclerosis Study clinical advisory. The volume of CEAs increased in every region of the country for all nonpsychiatric hospital classifications and for almost every surgeon subspecialty. Despite the increased volume, the operative mortality rate, the International Classification of Diseases, Ninth Revision, Clinical Modification--and patient management categories--based complication rates, and the patients' comorbidity and severity of illness indexes all remained unchanged. CONCLUSION: The dramatic increase in CEAs following the Asymptomatic Carotid Atherosclerosis Study clinical advisory suggests that the conclusions of the trial have been accepted by the medical community throughout the Veterans Affairs medical centers.
Adult↗
The impact of complications after vascular surgery in Veterans Affairs Medical Centers.
The impact of perioperative complications on clinical outcomes and resource utilization was assessed for 8702 veterans who, during fiscal years 1991-1994, underwent vascular surgery procedures in DRGs 110 and 111, which include aortic and peripheral aneurysm repairs as well as renal artery and some peripheral vascular reconstructions. In-hospital mortality rate was 6.2% (537/8702). Mortality was 9.8% with any ICD-9-CM-coded complication vs 4.9% without (P < 0.001). Mortality was 28.9% in those with both cardiac and pulmonary complications, 11.0% with either cardiac or pulmonary complications, and 3.7% with neither cardiac nor pulmonary complications. Length of stay (LOS) was 25.8 +/- 21.9 days with any ICD-9-CM-coded complication vs 18.9 +/- 14.1 days without (P < 0.001). Further, RIS (Resource Intensity Scale), a measure of intensity of resource utilization, was greater in those with (3.01 +/- 0.81) vs without (2.76 +/- 0.70; P < 0.001) a complication. Pulmonary complications impacted LOS and RIS more adversely than cardiac. A logistic regression model of mortality indicated that increasing age [odds ratio (OR) 1.065], arrhythmia (OR 1.31), pneumonia (OR 2.52), surgical complications of the heart (OR 2.8), respiratory insufficiency (OR 4.75), stroke (OR 5.48), MI (OR 5.78), and acute renal failure (ARF, OR 9.58) were associated with increasing likelihood for death, whereas treatment in the largest, academically affiliated VAMCs (RPM 5) was associated with reduced mortality (OR 0.795). Increasing age, treatment in the largest affiliated (RPM 5) hospitals, arrhythmia, MI, CHF, any ICD-9-CM-coded complication, acute renal failure, respiratory insufficiency, pneumonia, and stroke progressively increased LOS by linear regression analysis, whereas surgical complications of the heart and postoperative death reduced LOS. Complications after vascular surgery have an adverse impact on perioperative mortality, length of stay, and utilization of resources.
Acute Kidney Injury↗
Nonoperative therapy for postcatheterization femoral artery pseudoaneurysms.
Since November 1992, 160 patients were referred to the Vascular Surgery Laboratory for duplex scanning to assess whether a femoral artery pseudoaneurysm was present. Of these patients, 33 per cent (n = 53) had femoral artery pseudoaneurysms with maximal diameters ranging from 1.5 to 8.1 cm. Most pseudoaneurysms (79%; 42 of 53) followed diagnostic or therapeutic cardiac catheterization procedures. Pseudoaneurysms were treated by external compression using an ultrasound probe in 33 of these 53 patients, and thrombosis of the aneurysm was successfully induced in 76 per cent (n = 25) of those in whom nonoperative external compression therapy was attempted. Of the eight patients in whom compression was unsuccessful, three had severe pain that required cessation of compression, and femoral nerve involvement by the pseudoaneurysm was noted at surgery in two of the three. One additional patient refused a second attempt at compression due to discomfort. Of the other four failures of compression, four (50% overall) received anticoagulants during or prior to compression. In 25 patients with successful pseudoaneurysm thrombosis after external compression, none had severe pain from compression, and 40 per cent (n = 10) were on anticoagulants until or during compression. Four of the 53 (7.5%) pseudoaneurysms diagnosed in the vascular laboratory subsequently thrombosed spontaneously, and two patients (3.8%) experienced pseudoaneurysm rupture. Thrombosis of postcatheterization pseudoaneurysms can be achieved by nonoperative compression therapy in most patients. Severe pain during external compression suggests possible femoral nerve involvement by the pseudoaneurysm and is an indication for surgical therapy.
Aged↗
A mural thrombus of an infrarenal aortic aneurysm demonstrated as photon deficiency in a radionuclide study.
Radionuclide angiogram (RNA) and aortogram may underestimate external aneurysmal diameter. Photon deficient areas are not uncommon along the abdominal aortic aneurysm (AAA) on RNA. To determine whether or not photon deficient areas along the aneurysm could represent a large thrombus, we studied radionuclide aortic angiography in thirty-eight patients during a preoperative cardiac gated study. All the patients (men, ages from 60 to 78) had CT, US, and/or aortogram for comparison. The presence of a thrombus was determined by CT, US, and/or surgical findings. Twelve of 38 (32%) patients' RNA and blood pool images showed photon deficient areas along the aneurysmal walls having a large concentric or eccentric thrombus of the AAA. A large photon deficient area could be detected along the narrowing calibre of the aorta lumen. This finding results from a large mural thrombus being interposed between the left or right bowel/mesentery activity and the activity of the aneurysms functioning patent lumen. We concluded that a photon deficient area along an inferorenal aortic aneurysm may indicate a large thrombus of either eccentric or concentric type within an AAA.
Aged↗
Vena cava duplex imaging before caval interruption.
PURPOSE: Venacavograms are routinely obtained before vena cava filter placement to evaluate cava size, patency, and the presence of thrombus or venous anomalies. The objective of this study was to determine the ability of duplex ultrasonography to adequately evaluate the inferior vena cava (IVC) for size, patency, and the presence of thrombus before Greenfield filter (GF) insertion. METHODS: Duplex ultrasonographic scans were performed in 40 patients who had documented lower-extremity deep venous thrombosis diagnosed by duplex scan before GF placement. The infrarenal transverse and anteroposterior diameters of the IVC were measured, and the entire IVC was imaged for patency and the presence of thrombus or anomalies. Preoperative venacavograms were not obtained in any patients who had GFs placed in the operating room, but was performed during surgery during filter insertion. An additional 26 patients who had deep venous thrombosis and did not have caval interruption underwent IVC duplex to determine the patency and proximal extent of venous thrombosis. RESULTS: The indications for GF placement were contraindication to anticoagulation in 72.5% (29 patients); five filters were placed prophylactically; three for failure of anticoagulation; two after a complication of anticoagulation; and one before pulmonary embolectomy. The filters were placed in the operating room by surgeons in 82.5% of patients, with the remainder inserted in an angiography suite by an interventional radiologist. The ability of duplex to measure a transverse diameter of 26 mm or less had a sensitivity of 97.5%, positive predictive value of 100%, and overall accuracy of 97.5% using venacavography as the standard. Measurements of IVC diameter by duplex correlated with those based on venacavograms (r = 0.766; p < 0.001). Of the entire group of 66 IVC duplex examinations, one (1.5%) was incomplete because of technical limitations. IVC thrombus was noted by duplex in two patients who underwent GF insertion, which was confirmed with venacavography. No IVC anomalies were noted by duplex scans or venacavograms. CONCLUSION: Duplex ultrasonography is a useful and accurate method for assessment of the IVC before vena cava filter placement.
Adult↗
Abdominal aortic aneurysm repair in Veterans Affairs medical centers.
PURPOSE: This study was performed to define outcomes after abdominal aortic aneurysm (AAA) repair in Veterans Affairs (VA) medical centers during fiscal years 1991 through 1993. METHODS: With VA patient treatment file data, patients were selected from diagnosis-related groups 110 and 111 and were then classified in a patient management category. In the categories of repair of nonruptured and ruptured AAA, mortality and postoperative complication rates were defined for patients who underwent AAA repair in VA medical centers during the 3-year study period. RESULTS: Hospital mortality rates were 4.86% (166 of 3419) after repair of nonruptured AAA and 47.0% (126 of 268) after repair of ruptured AAA (p<0.001). Of 292 deaths after AAA repair, 136 (43.2%) followed repair of ruptured AAA, even though ruptured AAA comprised only 7.3% of total AAA surgical volume. AAA repairs were performed at 116 VA medical centers, with 31.8+/-23.1 (range, 1 to 140) procedures performed at each center. Although many lower-volume centers had excellent results, centers that performed >or=32 AAA repairs tended to have lower in-hospital mortality rates after repair of nonruptured AAA than those that performed <or=31 procedures (4.2%+/-3.5% compared with 6.7%+/-7.8%;p<0.05). Poisson regression analysis revealed an inverse relationship between the volume of AAA repairs and individual hospital mortality (p=0.001) and a direct relationship between illness severity and hospital mortality (p=0.008). The proportion of ruptured AAAs treated in a hospital was also directly related to individual hospital mortality rates (p<0.005). Postoperative complications were associated with an increased hospital mortality rate (11.7% with complication compared with 6.5% without; p<0.0001) and length of stay (23.6+/-17.1 days compared with 18.0+/-12.4 days; p<0.0001). In a logistic regression model, increased mortality rates after AAA repair were associated with hospital type (adjusted odds ratio [OR]=0.6), increasing age (OR=1.1), patient management category severity score (OR=2.2), hemorrhage (OR=2.3), myocardial infarction (OR=2.6), disseminated intravascular coagulation (OR=4.7), AAA rupture (OR=6.0), postoperative shock (OR=10.7), cardiopulmonary arrest (OR=15.4), central nervous system complications (OR=16.0) and urologic complications (OR=2.4). CONCLUSIONS: Mortality rates after AAA repair in VA hospitals were comparable with those previously reported in other large series. Outcomes for veterans with AAA may improve by referring patients eligible for elective repair to VA medical centers with a greater operative volume or to lower-volume centers that have had excellent results.
Age Factors↗
Assessment of noninvasive lower extremity arterial testing versus pulse exam.
Palpation of pedal pulses was compared to noninvasive testing in 100 patients referred to a vascular laboratory. Subjects were 65 +/- 13 (mean +/- s.d.) years old. The right dorsalis pedis (DP) artery served as the reference artery for comparison of Doppler studies with physical examination of the pulses. Absolute Doppler pressures in the right DP were 129 +/- 50 mm Hg. The right ankle:brachial index (ABI) was 0.86 +/- 0.32. There were significant differences in ABI in those with (0.68 +/- 0.28) vs without (0.95 +/- 0.31) claudication in either extremity (p < 0.001). Rest pain was also associated with lower ABI (P < 0.04). Diabetics, hypertensives, claudicants and those with ischemic rest pain were less likely to have palpable pulses (P < 0.035). With right DP pressure >/= 118 mm Hg, 63 per cent of subjects had a palpable DP pulse, whereas 68 per cent with ABI > 0.82 had a palpable right DP. Of those (n = 35) with a right DP pressure < 118 mm Hg, only 6 per cent (n = 2) had a palpable pulse, whereas 5 per cent (2/40) with ABI </= 0.82 had palpable DP pulses. Based on these findings, it was predicted that a pulse would likely not be palpable in the left DP with a pressure < 118 mm Hg or with AB </= 0.82. The prediction based on systolic ankle pressures was correct, with 66 per cent sensitivity and 91 per cent specificity. The predication that a left DP pulse would not be palpable with AB </= 0.82 was more accurate (78% sensitive, 97% specific). Presence of a palpable DP pulse suggests the presence of a Doppler pressure >/= 188 mm Hg and ABI > 0.82. The range of ankle pressures with palpable right DP pulses was 64-220 mm Hg, whereas the range with nonpalpable DP was 42-300 mm Hg. Given the frequent disparity of pulse exam and ankle pressures, noninvasive Doppler testing may be necessary for many patients to accurately assess the vascular status of the leg.
Adult↗
Thromboembolic complications of polycythemia: polycythemia vera versus smokers' polycythemia.
PURPOSE: This report compares patients with the hypercoagulable state of polycythemia vera to patients with secondary polycythemia caused by tobacco use to determine whether the incidence of thromboembolic events is equivalent. METHODS: The medical records of 146 patients with the diagnosis of polycythemia between 1977 to 1990 were reviewed. Patients with transient, relative, or stress polycythemia were excluded from this study as were patients with polycythemia as a result of cardiac or pulmonary anomalies or both. The diagnosis of polycythemia vera (n = 43) was verified by use of the guidelines of the Polycythemia Vera Study Group. The diagnosis of polycythemia caused by smoking (n = 27) was based on an elevated total red blood cell volume, decreased oxygen saturation on arterial blood gas measurement, evidence of chronic obstructive pulmonary disease, and elevated carboxyhemoglobin levels. RESULTS: Twenty-six patients (60%) with polycythemia vera and 11 patients (41%) with smoker's polycythemia had at least one thromboembolic problem. No significant differences existed between the groups with regard to age, hematocrit, or number of cardiac and cerebrovascular events. Overall, patients with polycythemia vera had a greater number of thromboembolic events per patient (p < 0.05) and more peripheral arterial thromboemboli (p < 0.005) than did patients with polycythemia as a result of smoking (Fisher's Exact Test). CONCLUSIONS: Thus the results of this study demonstrate that smokers' polycythemia does not represent a hypercoagulable state equivalent to that of polycythemia vera.
Analysis of Variance↗
Trauma to the proximal superior mesenteric artery: a case report and review of the literature.
Visceral arterial injuries account for a small but important portion of major abdominal vascular trauma. A case of proximal superior mesenteric artery trauma is presented. The advantages and drawbacks of the surgical approaches to these injuries are discussed. On the basis of a review of the literature describing the management of these injuries, ligation of the proximal superior mesenteric artery for trauma cannot be recommended. Prompt surgical intervention with revascularization offers the best chance for the survival of these critically injured patients.
Adult↗
Preoperative spirometry predicts perioperative pulmonary complications after major vascular surgery.
This study determined utility of preoperative spirometry for prediction of postoperative pulmonary complications (PPC) defined as pneumonia, ventilator dependence greater than 48 hours, and adult respiratory distress syndrome in 147 patients undergoing vascular surgery from June 1988 through March 1990 [39 aortic aneurysm repairs, 21 carotid procedures, and 87 operations for occlusive disease including aorto-ileofemoral, infra-inguinal, and visceral]. The incidence of PPC was 12.9 per cent, while cardiac complications (myocardial infarction, congestive heart failure, and ventricular arrhythmias) were present in 9.8 per cent. Prior or current smoking, which was present in 80 per cent, was not predictive of PPC. FEV1 was 2.2 +/- 0.7 L/s (mean +/- 1 SD). Abnormal FEV1 (2.0 or less L/s) was present in 42 per cent (n = 62). For FEV1 of 2.0 or less, PPC rate was 22.5 per cent versus 5.8 per cent for FEV1 greater than 2.0 L/s (P less than 0.005, Fisher exact). The incidence of PPC was 30.7 per cent for aortic aneurysm repair, 8.0 per cent for occlusive disease, and 4.7 per cent for carotid procedures. Abdominal aortic procedures (performed in 67 patients: 39 for aortic aneurysm repair and 28 for aortoiliac occlusive disease) were associated with a PPC rate of 22.4 per cent versus 5.0 per cent for "nonabdominal" procedures (P less than 0.002, Fisher exact). Life table analysis after surgery demonstrated decreased survival for patients with PPC (P = 0.031, Mantel-Haensel) during follow-up (250 +/- 165 days). PPC are associated with abnormal FEV1 and abdominal vascular procedures. In conclusion, preoperative spirometry is useful for the prediction of PPC after vascular surgery.
Diagnostic Tests, Routine↗
Pentoxifylline in the nonoperative management of intermittent claudication.
To assess the clinical effectiveness of pentoxifylline (Trental) in the treatment of intermittent claudication and ischemic rest pain, 129 patients were retrospectively interviewed with respect to compliance and improvement of symptoms. Risk factors for the development of atherosclerosis were tabulated, as was the severity of symptomatic lower extremity peripheral vascular insufficiency. The duration of pentoxifylline treatment was 35.8 +/- 45.0 weeks (mean +/- 1 S.D.). Forty-eight percent of the patients discontinued pentoxifylline on their own, most commonly because of side effects (13%) or perceived lack of improvement (23%). Of those patients taking pentoxifylline for eight weeks or more (n = 110), 64% noted some improvement, with 31% reporting increased claudication distance and 52% reduced claudication pain. Pentoxifylline provided pain relief in 52% of patients with ischemic rest pain (n = 27). Neither diabetes, hypertension, concomitant antiplatelet therapy, the severity of claudication, nor pretreatment ankle-brachial Doppler pressures were related to treatment outcome. Increased daily walking exercise during treatment was associated with successful outcome (p = 0.04). Clinical response to pentoxifylline was inversely related to the number of cigarettes smoked daily in those with 1 block claudication (n = 71, p = 0.05). Pentoxifylline was not very effective in increasing reported claudication distance. This review suggests that pentoxifylline may be of value for patients with ischemic rest pain when arterial reconstruction is not possible. Whether pentoxifylline is useful adjunctive therapy for intermittent claudication requires further scrutiny.
Aged↗
Thallium redistribution does not predict perioperative cardiac complications following vascular surgery.
Utility of preoperative stress thallium scintigraphy (STS) was determined in 59 patients, thought to be at increased risk, prior to major vascular surgery from July 1987 to February 1990. Forty-seven had oral dipyridamole and 12 underwent exercise STS. Thallium redistribution (TR) was present in 61% (n = 36); fixed defects were present in 59% (n = 35); and some combination of defects was present in 76% (n = 45). Perioperative cardiac complications (CC = congestive heart failure [n = 3], ventricular arrhythmia [n = 2], and MI [n = 1]) were present in 8.5% (6 CC in 5 patients). Incidence of CC was 8.3% (3/36) in those with TR, and 8.7% (2/23) without TR (relative risk = 0.95). Perioperative MI was present in 2.8% (1/36) with TR vs. 0% (0/23) without. Though mortality was 3.4%, no perioperative deaths were from cardiac disease. Utility of STS is not clearly established for prediction of perioperative cardiac risk after major vascular surgery.
Adult↗
Ruptured abdominal aortic aneurysm: the Harborview experience.
During the last decade (1980 to 1989) 186 patients with ruptured abdominal aortic aneurysm were admitted to a single urban hospital. Ninety-six percent of these patients had a prehospital systolic blood pressure less than 90 mm Hg. Management included paramedic field resuscitation and transport, an emergency department diagnostic protocol completed in an average of 12 minutes, rapid transport to a dedicated emergency operating room, aneurysmorrhaphy by general surgery chief residents under the supervision of specialist vascular surgeons, and skilled postoperative intensive care unit care. Nevertheless, 130 (70%) patients died in the first 30 postoperative days--3% in the emergency department, 13% in the operating room, 51% in the intensive care unit, and 3% on the ward or at home. Certain features--age greater than 80 years, female gender, persistent preoperative hypotension despite aggressive crystalloid and blood replacement, admission hematocrit less than 25, transfusion requirements exceeding 15 units--were associated with a greater than 90% likelihood of death. No patient with preoperative cardiac arrest survived more than 24 hours. From this experience we conclude that, although "optimal" prehospital, emergency department, operating room, and postoperative care can improve the outcome of patients with ruptured abdominal aortic aneurysms in shock, most such patients will die. Certain clinical features predict such excessive mortality rates after ruptured abdominal aortic aneurysms that withholding operation may be reasonable. Screening of patients at high risk for abdominal aortic aneurysm, followed by elective aneurysmorrhaphy, is clearly indicated.
Aged↗
Resection of abdominal aortic aneurysm in patients with low ejection fractions.
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Aorta, Abdominal↗
The role of preoperative radionuclide ventriculography in defining outcome after revascularization of the extremity.
Revascularization of the extremity was performed upon 110 patients after preoperative radionuclide ventriculography (RNVG). Mean ejection fraction (EF) was 50 +/- 13 per cent. Ventricular wall motion abnormalities were present in 46 per cent. Revascularization included inflow procedures, such as aortofemoral (n = 25) or extraanatomic bypass (axillofemoral or femorofemoral, n = 11); infrainguinal reconstruction, including femoropopliteal or distal bypass (n = 43), and other procedures to improve perfusion of the limb or correct complications after previous vascular reconstruction upon the extremity (n = 31). Perioperative (30 days) mortality rate was 0.9 per cent and 97.0 per cent of the patients were discharged alive from the hospital. Myocardial infarction (MI) occurred in 3.6 per cent, new ventricular arrhythmia in 1.8 per cent and congestive heart failure in 6.4 per cent of the patients during the perioperative period. During follow-up study (607 +/- 363 days), 7.3 per cent required major amputation, ipsilateral to reconstruction, 5.5 per cent required surgical or angiographic revision for hemodynamic failure of the reconstruction prior to thrombosis and 12.7 per cent thrombosed part or all of the reconstruction. Revascularization failure did not appear to be related to the level of cardiac function. Those with normal (greater than 50 per cent) EF had greater over-all survival by life table analysis than those with EF less than or equal to 50 per cent (p = 0.0006, Mantel-Cox test). Ventricular wall motion abnormalities were associated with reduced over-all survival (p = 0.008, Mantel-Cox test). The presence of angina or previous MI, singularly or in combination, did not have an adverse effect on over-all survival, whereas diabetes (p = 0.0058, Mantel-Cox test) and cigarette smoking (p = 0.0137, Breslow test) were associated with significantly diminished over-all survival. Preoperative RNVG can identify subgroups at a survival disadvantage after revascularization of the extremity in a population in which the presence of angina or previous MI does not predict survival.
Adult↗
Pentoxifylline increases extremity blood flow in diabetic atherosclerotic patients.
Pentoxifylline, a new trisubstituted methylxanthine derivative known for its hemorrheologic action, has been shown to improve exercise tolerance in atherosclerotic patients. We examined the responses of diabetic atherosclerotic patients to pentoxifylline administration, measured by Doppler waveform analysis and exercise tolerance. Standard exercise tolerance and Doppler waveform analytic studies of the lower extremity, specifically the right dorsalis pedis artery, were performed before and after three months of pentoxifylline administration (400 mg three times a day). The study group comprised ten subjects (six men and four women) with a mean (+/- SD) age of 60 +/- 3.3 years. Data were analyzed using a paired Student t test. All ten subjects showed a significant increase in exercise tolerance after pentoxifylline treatment. Eight of ten subjects demonstrated a significant increase in right dorsalis pedis arterial flow.
Arteries↗
Asymptomatic high-grade internal carotid artery stenosis: is stratification according to risk factors or duplex spectral analysis possible?
High-grade (80% to 99% diameter reduction) asymptomatic internal carotid artery stenoses are associated with an increased neurologic event rate (transient ischemic attack, stroke, asymptomatic internal carotid artery occlusion) compared to less severe asymptomatic lesions. However, many do remain free of associated events. To determine which are most dangerous, we compared risk factors and duplex scan results in two groups with asymptomatic high-grade internal carotid artery stenoses. Group A included 31 patients with 33 unoperated high-grade lesions that remained asymptomatic for at least 12 months (mean 30 months). Group B included 25 patients with 26 initially asymptomatic lesions that subsequently were associated with a neurologic event (mean time to event 7.4 months). The groups did not differ significantly in average age, sex, aspirin use, smoking, or prevalence of hypertension, diabetes, or cardiac disease. With respect to the index high-grade lesion, there was no difference in the frequency of a greater than 50% contralateral internal carotid artery stenosis or greater than 50% ipsilateral external carotid stenosis. However, on duplex scanning, high-grade stenoses with greater than 6.5 kHz end-diastolic frequencies were more frequently associated with an event than high-grade lesions with lower end-diastolic frequency (p = 0.0004). Similarly, seven of 23 lesions (30%) with end-diastolic frequency greater than 6.0 kHz were associated with subsequent internal carotid artery occlusion compared to only one of 29 (3.5%) with end-diastolic frequency less than or equal to 6.0 kHz (p = 0.025). Analysis of internal carotid artery end-diastolic frequency may help select a subgroup of patients with asymptomatic high-grade lesions who are at greatest risk for subsequent neurologic symptoms or ICA occlusion or both.
Aged↗