Paul S. van Bemmelen

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.

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.

Does air plethysmography correlate with duplex scanning in patients with chronic venous insufficiency

PURPOSE Duplex ultrasonography with distal cuff deflation was used to determine the presence and size of incompetent veins and compare the results with those of air plethysmography in patients with chronic venous insufficiency. METHODS Thirty-two legs underwent a detailed study with both modalities. Sixteen legs had venous ulceration, six had stasis dermatitis, and ten had symptomatic varicose veins without skin changes. RESULTS Although the venous filling index (VFI) in limbs with ulcers (5.4 +/- 3.8 ml/sec) and dermatitis (7.7 +/- 4.6 ml/sec) was significantly higher (p < 0.05) than it was in limbs with varicose veins (2.6 +/- 1.7 ml/sec), there was a large amount of overlap. Only 13% of ulcerated legs had VFI greater than 10 ml/sec. Sixty-three percent of legs with ulcers, 33% of legs with dermatitis, and 90% of legs with varicose veins had VFIs less than 5 ml/sec. Mean ejection fractions (EFs) in the three groups were similar, ranging from 45% to 52%. Combining VFI and EF did not lessen the overlap between groups. Forty-one percent of limbs with ulcers or dermatitis had air plethysmography parameters in the normal or intermediate area (VFI < 5 ml/sec; EF > 40%), which in previous studies corresponded to an incidence of ulceration of only 2%. VFI had a significant but weak correlation (r = 0.39) with the diameter of incompetent veins at the knee and a somewhat stronger relationship (r = 0.55) with the diameter of lower leg veins. Total venous volume correlated moderately well with calf vein diameter (r = 0.75). The clinical status of the leg did not correlate with the diameters of incompetent veins at the knee or calf levels. All limbs with an obstructed outflow had EFs less than 60% and ulcers or dermatitis. CONCLUSIONS We conclude that plethysmographic measurements of functional venous parameters (VFI,EF) do not discriminate well between limbs with uncomplicated varicose veins and limbs with ulcers or stasis dermatitis and that VFI correlates poorly with the presence of incompetent veins and their diameters. Both duplex scanning and plethysmography seem to be necessary for a complete evaluation of limbs with chronic venous insufficiency.

Augmentation of blood flow in limbs with occlusive arterial disease by intermittent calf compression

PURPOSE This study was designed to investigate the effect of intermittent calf compression on popliteal arterial blood flow and to see how flow is influenced by position of the subject and by arterial blood pressure at the ankle. METHODS Volume flow in the popliteal artery of subjects in the sitting and prone positions was measured with duplex ultrasonography before inflation and immediately after deflation of a pneumatic cuff placed around the calf. Eleven legs of control subjects and 41 legs of patients with symptoms (32% patients with diabetes) with decreased ankle pressure were studied. Cuffs were inflated for 2 seconds at pressures ranging from 20 to 120 mm Hg. RESULTS An increase in arterial blood flow of two to eight times (mean 4.4 +/- 2.0) was found on deflation of the cuff in seated control subjects. Little change in flow was observed when the subjects were in the prone position. In seated patients with arterial obstruction, the mean increase in arterial flow was 3.2 +/- 1.6 times the resting flow. Little correlation was found between the maximum increase in flow and the ankle/brachial index. CONCLUSIONS An increased arteriovenous pressure gradient accounts for some but not all of the flow increase, much of which must be attributable to transient vasodilatation. Because the increase in flow does not depend on an increased inflow pressure and was not adversely affected by a low resting ankle-brachial pressure index or a low toe-pressure, intermittent external limb compression may deserve investigation as a possible adjunct to the nonoperative treatment of patients with severe arterial insufficiency.

Routine surveillance after carotid endarterectomy: Does it affect clinical management? *

PURPOSE Although routine noninvasive surveillance is recommended after carotid endarterectomy (CEA), there are little data to show that identification and eradication of recurrent carotid artery stenosis are necessary to avoid the risk of subsequent neurologic complications. METHODS We reviewed our experience over a 16-year period in 380 consecutive patients undergoing 409 CEAs who underwent serial postoperative ultrasonic scanning at 6 weeks, 6 months, and 1 year after CEA and then yearly thereafter. RESULTS Recurrent stenoses (> or = 50% diameter reduction) were detected in 44 arteries (10.8%) during follow-up from 1 to 177 months (mean 42.0 months). Most (70.5%) occurred within 2 years of CEA. Cumulative recurrence rates were 5.8%, 9.9%, 13.9%, and 23.4% at 1, 3, 5, and 10 years, respectively. Recurrent stenoses were more frequent in female (p = 0.02) and younger patients (p = 0.01) and less frequent in those having a vein patch repair (p = 0.02). Most recurrences (84%) were in the 50% to 79% stenosis range. In four patients 80% to 99% stenoses developed and in three patients total occlusions developed, for a severe recurrence rate of 2.1%. Only 10 (22.7%) of the recurrent stenoses were initially symptomatic, and only one (2.9%) of the asymptomatic restenoses later became symptomatic. One patient with recurrent stenosis suffered a stroke (0.3%). Cumulative 5-year ipsilateral stroke-free rates in patients with recurrent stenosis (94.4%) were practically identical (p = 0.76) to those in patients without recurrent stenosis (94.2%). Life-table ipsilateral stroke-free survival rates at 5 years were 94.2% in patients with recurrent stenosis and 78.4% in patients without recurrent stenosis (p = 0.16). Four (9%) recurrent stenoses and 12 lesions (27%) in the contralateral artery progressed. Only seven patients (1.7%) underwent repeat operation for ipsilateral disease, four for symptoms and three for recurrent stenosis. CONCLUSIONS Recurrent carotid artery stenosis occurs early after CEA, is typically benign, and remains stable over a prolonged follow-up period. Our results question the importance of routine noninvasive surveillance after CEA and suggest that a more conservative approach would be equally beneficial in terms of clinical relevance and cost-effectiveness.

The influence of carotid siphon stenosis on short- and long-term outcome after carotid endarterectomy

PURPOSE This study was designed to determine whether the presence of ipsilateral carotid siphon stenosis influenced the risk of early and late stroke and death after carotid endarterectomy (CEA). METHODS The outcomes of patients with moderate (20% to 49%), severe (> 50%), and no siphon stenosis were compared over a 16-year period from April 1976 to February 1992. Complete angiographic data were available in 393 carotid arteries. RESULTS Siphon stenosis was found ipsilateral to the CEA in 84 (21.4%) of the arteries. Most lesions were in the 20% to 49% diameter-reducing range (77.4%), with the remainder in the greater than 50% range (22.6%). There were no occlusions. The perioperative mortality rate was nearly identical for the groups with and without siphon stenosis, 0.0% versus 0.6%, respectively (p = 0.99). Perioperative stroke morbidity rates (no stenosis, 2.3%; moderate stenosis, 3.1%; > 50% stenosis, 5.3%) were acceptable and were not statistically different (p > 0.38). Late ipsilateral stroke-free rates were similar in the groups with and without siphon stenosis. The 5- and 7-year stroke-free incidences were 88.5% and 83.4% versus 94.9% and 94.9%, respectively (p > 0.20) for the two groups. Long-term ipsilateral stroke-free rates were not significantly different in the subgroups with moderate (20% to 49%) and hemodynamically significant (> 50%) siphon stenosis. The 3- and 5-year ipsilateral stroke-free rates were 96.7% and 87.9% versus 94.6% and 94.6%, respectively (p = 0.69). Late death was more common in the group with siphon stenosis than it was in the group without siphon stenosis, 23.8% versus 12.5% (p = 0.02). Heart disease was responsible for most late deaths, 47% in both groups. Late stroke-related deaths were infrequent: 1.3% in patients with and 0.0% in patients without siphon stenosis. CONCLUSIONS Although carotid siphon stenosis seemed to be associated with a higher risk of late death, it did not alter the short- and long-term stroke morbidity rates after carotid endarterectomy significantly. We conclude that the presence of carotid siphon stenosis should not influence the decision to perform carotid endarterectomy in patients with the appropriate indications.

Presentation and natural history of internal carotid artery occlusion

PURPOSE This retrospective study was undertaken to investigate the effect of presenting neurologic symptoms, vascular risk factors, and degree of contralateral internal carotid artery stenosis on subsequent stroke and death rates of patients with internal carotid artery occlusion (ICO). METHODS One hundred sixty-seven patients with ICO were evaluated over a 5-year period. Mean follow-up was 39 months. Initial symptoms included transient ischemic attack in 29 patients (17%), stroke in 71 patients (43%), nonhemispheric symptoms in 22 patients (13%), and no symptoms in 45 patients (27%). Ninety percent of the presenting strokes occurred ipsilateral to the ICO. RESULTS During follow-up 54 (32%) patients died, 10 (19%) of stroke and 22 (41%) of heart disease. The 5-year cumulative survival rate was 63%. Subsequent neurologic events occurred in 26% of the patients. Thirty patients (18%) had a stroke during follow-up, of which 20 (67%) occurred ipsilateral to the ICO. The 5-year stroke-free rate was 76%. Patients who had a stroke had a less favorable 4-year stroke-free rate (67%) than those who had transient ischemic attack (92%) or those who originally had no symptoms (89%), p = 0.03 and p = 0.04, respectively. In addition, there was a trend towards a worse 5-year contralateral stroke-free rate in patients with contralateral stenosis of 50% to 99% (77%) compared with patients with less than 50% contralateral stenosis (94%), p = 0.08. Twenty patients underwent carotid endarterectomy on the nonoccluded side. There were no perioperative strokes or deaths. Carotid endarterectomy seemed to reduce the long-term stroke morbidity rate (p = 0.10) on the operated side in patients with 80% to 99% contralateral stenosis but did not perceptibly improve stroke-free rates on the occluded side or in patients with 50% to 79% stenosis. CONCLUSION Patients with ICO have a variable prognosis. There is a significant incidence of subsequent stroke, which seems to be related to the presenting neurologic event and the degree of stenosis in the contralateral internal carotid artery.

PC162. Outcomes of Below-Knee Amputation for Lower Extremity Infection: One-Stage versus Two-Stage Operative Approach

6 3.5. The risk score was divided into low-risk [0-4 points, n 1⁄4 5,272 (52%); NHD 1⁄4 10.1%] moderate-risk [5-9 points, n 1⁄4 3663 (36.7%) NHD 1⁄4 36.7%], and high-risk [10 points, n 1⁄4 1210 (11.9%) NHD 1⁄4 66.1%). Conclusions: A novel risk score was highly predictive for NHD after bypass for LEI using only preoperative comorbidities. High-risk patients account for 12% of bypasses but nearly a third of all patients with NHD. This risk score can be used to determine high-risk patients for discharge preoperatively allowing providers to anticipate their need in the preoperative setting or upon immediate presentation to the hospital.

IP205. Outcomes After Open Lower Extremity Revascularization in Patients With Chronic Kidney Disease

(range, 1-79 months) with a primary patency of 85.4%. Cumulative primary assisted and secondary patency was 92.6%. The femoral patch repair was the most frequent site of reintervention. Mortality was 34% overall during the study period with one death at 30 days. Conclusions:Hybrid approach has lowmorbidity andmortality and fast recovery. It is a safe, effective and lasting treatment for TASC C and D aortoiliac occlusive disease involving the femoral bifurcation. The use of covered stents provides good midterm patency. Close follow-up with noninvasive imaging is paramount to avoiding repair failure by diagnosing recurrent stenosis, in particular at the femoral patch repair site.