David S. Sumner

Classification and Grading of Chronic Venous Disease in the Lower Limbs-A Consensus Statement-

Classification and grading of chronic venous disease in the lower limbs : A consensus statement

Noninvasive diagnosis of neonatal asphyxia and intraventricular hemorrhage by Doppler ultrasound.

The cerebrovascular hemodynamic alterations in asphyxia and intracerebral-intraventricular hemorrhage were determined by monitoring the pulsatile flow changes in the anterior cerebral arteries using Doppler ultrasound. The pulsatility index measurements, which were calculated from the recorded changes in Doppler frequency shifts, were obtained in four groups of newborn infants with the following diagnoses: Group I--normal term (n=21); Group II--asphyxia (n=12); Group III--IC-IVH (n=14); and Group IV--asymptomatic preterm (n=11). There was no significant difference between PI values of Groups I and IV. Compared to normal term infants, those diagnosed as having asphyxia had significantly lower PI measurements and those with IC-IVH had significantly higher PI values than the asymptomatic pretern infants. Serial Doppler studies were also performed in 22 preterm infants with respiratory distress. One-half of these infants subsequently developed IC-IVH. Prior to hemorrhage, their PI measurements were significantly lower than those who did not eventually have the complication. The low PI values in asphyxia and prior to the onset of IC-IVH indicate vasodilation and decreased resistance to blood flow. In IC-IVH, the high PI measurements denote the opposite. In infants with respiratory distress in the presence of significant vasodilation and lowered vascular resistance, CBF may increase to excessive levels, resulting in IC-IVH.

The hemodynamics and diagnosis of venous disease

The venous system is, in many respects, more complex than the arterial system and a thorough understanding of venous anatomy, pathophysiology, and available diagnostic tests is required in the management of acute and chronic venous disorders. The venous system develops through several stages, which may be associated with a number of development anomalies. A thorough knowledge of lower extremity venous anatomy, anatomic variants, and the recently updated nomenclature is required of all venous practitioners. Effective venous return from the lower extremities requires the interaction of the heart, a pressure gradient, the peripheral muscle pumps of the leg, and competent venous valves. In the absence of pathology, this system functions to reduce venous pressure from approximately 100 mm Hg to a mean of 22 mm Hg within a few steps. The severe manifestations of chronic venous insufficiency result from ambulatory venous hypertension, or a failure to reduce venous pressure with exercise. Although the precise mechanism remains unclear, venous hypertension is thought to induce the associated skin changes through a number of inflammatory mechanisms. Several diagnostic tests are available for the evaluation of acute and chronic venous disease. Although venous duplex ultrasonography has become the standard for detection of acute deep venous thrombosis, adjuvant modalities such as contrast, computed tomographic, and magnetic resonance venography have an increasing role. Duplex ultrasonography is also the most useful test for detecting and localizing chronic venous obstruction and valvular incompetence. However, it provides relatively little quantitative hemodynamic information and is often combined with measurements of hemodynamic severity determined by a number of plethysmographic methods. Finally, critical assessment of venous treatment modalities requires an understanding of the objective clinical outcome and quality of life instruments available.

Color-flow duplex scanning of carotid arteries: New velocity criteria based on receiver operator characteristic analysis for threshold stenoses used in the symptomatic and asymptomatic carotid trials

PURPOSE Duplex scanning has become the standard for noninvasive evaluation of carotid arteries. However, current ultrasound criteria for internal carotid artery (ICA) stenosis (16% to 49%, 50% to 79%, 80% to 99%) may not be applicable to the categories (30% to 49%, 50% to 69%, 70% to 99%) used in ongoing symptomatic and asymptomatic carotid endarterectomy trials. This study was undertaken to determine new velocity criteria consistent with these categories. METHODS From January 1, 1989 through October 30, 1992, 5871 color-flow duplex scans were obtained in our laboratories. After inadequate arteriograms and patients with a contralateral ICA occlusion were excluded, 770 peak systolic velocity (PSV) and 229 end-diastolic velocity (EDV) measurements were available for comparison with arteriography. ICA PSV and EDV were subjected to receiver operator characteristic curve analysis to determine optimum criteria for identifying stenoses of 30%, 50%, and 70%. RESULTS For 70% to 99% carotid artery stenosis, PSV greater than 130 plus EDV greater than 100 provided the best sensitivity (81%), specificity (98%), positive predictive value (89%), negative predictive value (96%), and overall accuracy (95%). For 50% to 69% stenosis, a PSV greater than 130 and EDV of 100 or less cm/sec proved to be the best combination: sensitivity (92%), specificity (97%), positive predictive value (93%), negative predictive value (99%), and accuracy (97%). Stenoses in the 30% to 49% range were less accurately identified. CONCLUSION These redefined criteria may prove useful for analyzing duplex ultrasound velocity data in reference to the classification of ICA stenosis used in recent clinical trials of the safety and efficacy of carotid endarterectomy.

Prospective evaluation of new duplex criteria to identify 70% internal carotid artery stenosis☆☆☆★

PURPOSE Large multicenter trials (North American Symptomatic Carotid Endarterectomy Trial, European Carotid Surgery Trial) have documented the benefits of carotid endarterectomy for treating symptomatic patients with >or=70% stenosis of the internal carotid artery. Although color-flow duplex scanning has become the preferred method for noninvasive assessment of internal carotid artery disease, no criteria have been generally accepted to identify this subset of patients. We previously reported a retrospective series to establish such criteria. This study details our results when these criteria were applied prospectively. METHODS Carotid color-flow duplex scans were compared with arteriograms in 457 patients who underwent both studies. Criteria for >or=70% internal carotid artery stenosis were peak systolic velocity >130 cm/sec and end-diastolic velocity >100 cm/sec. Internal carotid arteries with peak systolic velocity <40 cm/sec in which only a trickle of flow could be detected were classified as preocclusive lesions (95% to 99% stenosis). Arteriographic stenosis was determined by comparing the diameter of the internal carotid artery at the site of maximal stenosis to the diameter of the normal distal internal carotid artery. RESULTS Internal carotid artery stenosis of >or=70% was detected with a sensitivity of 87%, specificity of 97% positive predictive value of 89%, negative predictive value of 96%, and overall accuracy of 95%. Eighty-seven percent of 70% to 99% stenoses were correctly identified. False-positive errors (n=10) were attributed to contralateral internal carotid artery occlusion or high-grade (>90%) stenosis (n=5) and to interpreter error (n=1); no explanation was apparent in the other four. Eleven of 12 false-negative examinations occurred in patients with 70% to 80% internal carotid artery stenosis. CONCLUSIONS In our laboratories, prospective application of the above velocity criteria identified internal carotid artery stenosis of >or=70% with a reasonably high degree of accuracy. Errors occurred when stenoses were borderline and in patients with severe contralateral disease. With suitably modified velocity criteria, color-flow duplex scanning remains the most reliable noninvasive method for identifying symptomatic patients who are candidates for carotid endarterectomy.

Color-flow duplex scanning for the surveillance and diagnosis of acute deep venous thrombosis.

Compared with conventional duplex imaging, color-flow scanning facilitates the identification of veins (especially below the knee), decreases the need to assess Doppler flow patterns and venous compressibility, and allows veins to be surveyed longitudinally. These advantages translate into a less demanding and time-consuming examination. This study was designed to determine the accuracy of color-flow scanning for detecting acute deep venous thrombosis in patients in whom the diagnosis is clinically suspected and in asymptomatic patients at high risk for developing postoperative deep venous thrombosis. The diagnostic group included 77 limbs of 75 patients, and the surveillance group included 190 limbs of 99 patients undergoing total hip or knee replacement. All patients were prospectively examined with color-flow scanning and phlebography. In the diagnostic group, the incidence of thrombi in below-knee veins (47%) was approximately equal to that in above-knee veins (43%); but in the surveillance group, the incidence of thrombi in below-knee veins (41%) far exceeded that in veins above the-knee (3%). Nonocclusive clots and clots isolated to a single venous segment were more common in the surveillance group. In symptomatic patients, color-flow scanning was 100% sensitive and 98% specific above the knee and 94% sensitive and 75% specific below the knee. In the surveillance group, color-flow scanning was significantly (p less than 0.001) less sensitive (55%) for detecting thrombi, 93% of which were confined to the tibioperoneal veins. Negative predictive values were 100% and 88% for the diagnostic and surveillance limbs, respectively. Positive predictive values were 80% for the diagnostic limbs and 89% for the surveillance limbs. Color-flow scanning effectively excludes above-knee deep venous thrombosis in symptomatic patients and asymptomatic high-risk patients and predicts the presence of above-knee thrombi in patients in the diagnostic group with reasonable accuracy (97%). We conclude that color-flow scanning is as accurate as conventional duplex imaging and, because of its advantages, is the noninvasive method of choice for evaluating patients with suspected deep venous thrombosis. Its role in the surveillance of patients at high risk remains to be determined and awaits further clinical evaluation.

Does correction of stenoses identified with color duplex scanning improve infrainguinal graft patency

PURPOSE This study was undertaken (1) to determine whether correction of infrainguinal bypass stenoses detected with color duplex scanning (CDS) improved graft survival and (2) to define the natural history of grafts that did not undergo revision. METHODS Over a 39-month period 462 color-flow duplex scans were obtained on 170 limbs with autogenous vein grafts. Grafts were scanned within 3 months of operation, at 6 and 12 months, and then yearly. Doubling of the velocity at any point in the graft-arterial system compared with the velocity immediately above or below (velocity ratio > or = 2.0) was the criterion adopted for identification of a hemodynamically significant (> or = 50%) diameter reduction. RESULTS One hundred ten stenoses were detected in 62 (36%) of the limbs, of which 9 (8%) were in native vessels, 30 (27%) were at the anastomoses, and 71 (65%) were in the graft itself. Seventy-seven percent of the stenoses were detected in the first year. Twenty-four (39%) of the grafts with positive scans were revised. During follow-up, occlusions occurred in 10 (9%) of the 108 grafts with negative scans (NEG), in 2 (8%) of the 24 revised grafts with positive scans (PR), and in 10 (26%) of the 38 non-revised grafts with positive scans (PNR). Cumulative patency rates of NEG grafts were 90% at 1 year and 83% at 2 through 4 years. Similar patency rates were found in the PR vein grafts: 96% at 1 year and 88% at 2 through 4 years. In contrast, patency rates in PNR grafts with 50% or greater stenoses were only 66% at 1 year and 57% at 2 through 4 years. Log-rank tests showed a significant difference between the cumulative patency rates of NEG and PNR grafts (p < 0.002) and between PR and PNR grafts (p = 0.02). Flow velocities less than 45 cm/sec and ankle/brachial indexes did not discriminate well between grafts with or without 50% or greater stenoses or identify those grafts that subsequently occluded. CONCLUSIONS The results of this study suggest that CDS detects graft-threatening lesions, that a velocity ratio of 2.0 or greater is the most highly predictive parameter, and that revision of grafts with stenoses identified with CDS prolongs patency.

Special iliac artery considerations during aneurysm endografting.

BACKGROUND The feasibility of endograft exclusion of abdominal aortic aneurysms (AAA) has been established. However, the technical challenges of graft delivery through tortuous or diseased iliac arteries and the treatment of associated iliac aneurysmal disease have received little attention. METHODS Over 19 months, 74 patients underwent endoluminal repair of AAA and/or iliac artery aneurysms. Iliac anatomy that required special consideration during endografting was reviewed. RESULTS Of the 74 patients, 35 (47%) had iliac anatomy that required special attention. Thirteen patients (18%) had aneurysmal involvement of a common iliac artery. Eleven of these patients required endograft extension into the external iliac artery (EIA) and hypogastric coil embolization due to the proximity of the aneurysm to the hypogastric origin. Eleven patients with ectatic, nonaneurysmal iliac arteries required aortic cuffs to achieve a distal seal in these oversized vessels. Iliac artery tortuosity or stenosis were complicating factors in 27 of the 74 patients (36%), requiring the use of brachial guidewire tension in 2 patients to facilitate tracking of the delivery device. Five patients with severely splayed aortic bifurcations required crossed placement of the iliac limbs to prevent kinking of the endograft. Occlusive atherosclerotic disease of the EIA mandated preprocedural dilatation and stenting in 3 patients and postprocedural surgical EIA reconstruction in another 5 patients. Three patients who underwent successful endograft placement required subsequent endovascular repair of traumatized EIAs. CONCLUSIONS Iliac artery anatomy plays a significant role in the endoluminal treatment of infrarenal abdominal aortic aneurysms, complicating the procedure in up to 47% of patients with otherwise suitable anatomy. A variety of supplemental procedures, both surgical and endovascular, may be required to facilitate endograft placement. A special understanding of these constraints and proper planning is required for optimal therapy.

Relationship of severity of lower limb peripheral vascular disease to mortality and morbidity: A six-year follow-up study ☆ ☆☆

Among the considerations affecting the therapeutic approach to patients with atherosclerosis of the lower extremities is their associated risk of death, myocardial infarction, stroke, and limb loss. To investigate the relationship of these events to the severity of peripheral vascular disease we undertook a 6-year review of 247 consecutive patients undergoing lower extremity noninvasive vascular assessment. There were 130 men and 117 women with a mean age of 65 +/- 15 years. Patients were categorized into four groups according to their ankle-brachial pressure indexes at their first visit. Ninety-seven patients had normal indexes (greater than or equal to 0.92), 86 had indexes of 0.50 to 0.91, 39 had indexes of 0.31 to 0.49, and 25 had indexes within the ischemic range, less than or equal to 0.30. At 6 years 64% of the patients with ischemic indexes were dead. This incidence was significantly higher than that of any other patient category (p less than 0.01). Diabetes also had a significantly adverse effect on survival. The incidence of stroke and myocardial infarction was similar for all disease groups. Thirteen percent and 32% of patients with indexes of 0.31 to 0.49 and less than or equal to 0.30, respectively, underwent limb amputation. We conclude that patients with evidence of mild to moderate peripheral vascular disease have a survival rate and risk of vascular-related disorders similar to those of patients of similar age with little evidence of disease, whereas an ankle-brachial pressure index less than or equal to 0.30 is associated with a malignant prognosis.

Infrapopliteal bypass for severe ischemia: Comparison of autogenous vein, composite, and prosthetic grafts ☆

Results of 253 consecutive bypass grafts to infrapopliteal arteries were reviewed. Most (92%) were placed for rest pain (103) or tissue loss (130). Autogenous veins were used in 175 (69%) cases, composite vein-prosthetic grafts were used in 45 (18%), and prosthetic grafts alone were used in 33 (13%). Follow-up ranged from 0 to 101 months (mean, 19 months); 37 grafts (15%) were lost to follow-up. The operative mortality rate was 4%, and 5-year patient survival rate was 44%. Limb salvage was 82% at 5 years. The 5-year patency of vein grafts (63%) exceeded that of both composite (28%) and prosthetic (7%) grafts (p = 0.005 and p = 0.00007, respectively); but the patency of composite and prosthetic grafts did not differ significantly (p = 0.29). The patency of reversed vein (59%) and in situ vein grafts (74%) was not significantly different at 5 years (p = 0.34). Patency was also not affected by the site of the proximal or distal anastomoses or diabetes. The major determinant of long-term patency in infrapopliteal reconstructions continues to be graft material. Composite grafts offered no clear advantage over prosthetic grafts, and both should be used only when there is no other alternative to amputation.