Carotid endarterectomy in women: challenging the results from ACAS and NASCET

OBJECTIVE

To evaluate and compare the short- and long-term outcomes in female and male patients after carotid endarterectomy (CEA).

SUMMARY BACKGROUND DATA

Randomized carotid trials have clearly shown the benefits of CEA in specific symptomatic and asymptomatic patients. However, the short- and long-term benefits in women appear to be less clear, and the role of CEA among women with carotid disease remains uncertain.

METHODS

During a 21-year period, 1,204 CEAs were performed, 464 (39%) in women and 739 (61%) in men. Complete follow-up was available in 70% of patients.

RESULTS

Women were less likely to have evidence of coronary artery disease, were more likely to be hypertensive, and had a significantly greater incidence of diabetes. The mean age at CEA was 68.5 +/- 9.5 years for women and 68.0 +/- 8.5 years for men. There were no significant differences in the use of shunts, patching, tacking sutures, or severity of carotid stenoses between men and women. Surgical death rates were nearly identical for asymptomatic and symptomatic patients. Perioperative stroke rates were similar for asymptomatic and symptomatic patients. Life-table stroke-free rates at 1, 5, and 8 years were similar for asymptomatic women and men and symptomatic women and men. Long-term survival rates at 1, 5, and 8 years were higher for asymptomatic women compared with men and for symptomatic women compared with men. As a result, stroke-free survival rates at these follow-up intervals were greater for asymptomatic women compared with men, and for symptomatic women compared to men.

CONCLUSIONS

The results from this study challenge the conclusions from the Asymptomatic Carotid Endarterectomy Study and the North American Symptomatic Carotid Endarterectomy Trial regarding the benefits of CEA in women. Female gender did not adversely affect early or late survival, stroke-free, or stroke-free death rates after CEA. The authors conclude that CEA can be performed safely in women with asymptomatic and symptomatic carotid artery disease, and physicians should expect comparable benefits and outcomes in women and men undergoing CEA.

A prospective study of discharge disposition after vascular surgery

OBJECTIVE

The purpose of this study was to determine what factors are predictive of a decline in independent living after vascular surgery during recovery.

METHODS

Demographics, risk factors, operations, complications, wound status, and discharge disposition for all patients admitted to a tertiary vascular surgery service for any surgical procedure were prospectively recorded at the time of discharge. The declining order of dispositions at discharge were home (no professional assistance), home (professional assistance), rehabilitation facility, and skilled nursing facility.

RESULTS

Over a 15-month period, 380 patients underwent 442 primary operations. Primary operations included 74 (17%) carotid procedures, 38 (8%) aortic procedures, 186 (42%) extremity revascularizations, 29 (7%) major amputations, 45 (10%) minor amputations, and 70 (16%) other. There were 148 (33%) complications and 85 (20%) subsequent operations (same hospitalization); 159 (36%) open wounds occurred. Forty-six percent of the patients were discharged to home (no professional assistance), 28% to home (professional assistance), 3% to a rehabilitation facility, and 18% to a skilled nursing facility; 5% died. At discharge, 51% of patients required professional assistance, 39% had a decline in disposition, and 12% went from home (+/- professional assistance) to a facility. By multivariate regression analysis, a hospital stay more than 6 days, emergency operation, open operative wound, systemic complications, and minor amputation were significantly associated (P <.001) with a decline in disposition at discharge (odds ratios: 5.5, 3.7, 3.6, 3.6, and 2.8, respectively).

CONCLUSIONS

Prospective study reveals that a large proportion of patients (39%) had a decline in disposition after vascular surgery. A hospital stay more than 6 days, emergency operation, open operative wound, systemic complications, and minor amputation were strong independent predictors of decline. This information suggests modifications in treatment strategies may improve independent living status after vascular surgery and decrease the intense use of extended care resources required for this patient population during recovery.

Factors affecting the diagnosis of peripheral vascular disease before vascular surgery referral

OBJECTIVE

Many new patients evaluated by vascular surgeons are referred by internal medicine physicians (IMPs). Objectives shared by vascular surgeons and IMPs include early identification of peripheral arterial disease (PAD), improved referral relationships, and reduction of health care costs. The approach to PAD by IMPs and identification of deficiencies that might contribute to suboptimal care form the basis for this report.

METHODS

An anonymous survey was mailed to all IMPs (n = 843) in the central and southern parts of Illinois. Questions concerned IMP demographics, approach to diagnostic testing, referral patterns, perception of adequacy of education of PAD, and how often parts of the history and physical examination for PAD would be performed on the initial office visit of a hypothetical 65-year-old male with hypertension (each answer measured as 0%-25%, 25%-50%, 50%-75%, and 75%-100% of the time completed).

RESULTS

There was a response from 360 IMPs: 230 IMPs (27.3%) returned the questionnaire, and 130 IMPs (15.4%) declined to participate. Practice locations for IMPs returning the questionnaire included rural (36%), suburban (22%), and urban (40%). Practice types included academic (7%), solo private (29%), group private (53%), and other (14%). A history of cardiac disease was obtained most of the time by 92% of IMPs (75%-100% answer category). Histories for pulmonary disease, diabetes mellitus, stroke, and smoking were obtained most of the time with similar frequencies (85%, 86%, 73%, and 96%, respectively). In contrast, only 37% obtained a history for claudication, and 26% obtained a history for foot ulceration 75% to 100% of the time (P <.05, all comparisons). Examination of the heart (95%) and lungs (96%) occurred most of the time (75%-100% answer category) compared with each part of the pulse examination (range, 34%-60%; P <.05, all comparisons) and aortic aneurysm palpation (39%; P <.05). If pedal pulses were absent, examination by IMPs with Doppler scan and ankle-arm indices were mostly distributed in the 0% to 25% answer category (79% and 79%, respectively). After suspecting PAD, most IMPs obtained diagnostic tests first compared with specialist referral: carotid disease (91% vs 9%), aortic aneurysm (91% vs 9%), and lower extremity PAD (86% vs 14%). Initial referral patterns were made to vascular surgeons (49%), general surgeons (33%), cardiothoracic surgeons (13%), cardiologists (4%), and radiologists (1%). Most IMPs believed medical school (70%) and residency (73%) provided adequate training for PAD diagnosis.

CONCLUSIONS

Deficiencies may exist in the identification of PAD by IMPs that could adversely affect diagnosis, time to referral, health care costs, and ultimately, patient outcome. Improvements in medical school education and IMP training in the diagnosis of PAD are needed.

Algorithm for the diagnosis and treatment of endoleaks

BACKGROUND

Endoluminal grafting of abdominal aortic aneurysms (AAA) has shown promising early results. However, endoleaks present a new and challenging obstacle to successful aneurysm exclusion. We report our experience with primary, persistent endoleaks and provide an algorithm for their diagnosis and management.

METHODS

Over a 19-month period, 73 patients underwent endoluminal repair of their AAAs using a modular bifurcated endograft as part of a US FDA Investigational Device Exemption trial. Spiral computed tomography (CT) scanning was performed prior to discharge after repair to evaluate for complete aneurysm exclusion. If no endoleak was present on that initial CT scan, color-flow duplex scanning was performed at 1 month, with repeat CT scanning at 6 months and 1 year. If the initial CT scan revealed the presence of an endoleak, repeat CT scanning was performed at 2 weeks, 1 month, and 3 months, or until the endoleak resolved. Any patient with an endoleak that persisted beyond 3 months underwent angiographic evaluation to localize the source of the leak.

RESULTS

At 1 month, 62 patients (85%) had successful aneurysm exclusion. The remaining 11 patients (15%) had primary endoleaks, 8 (11%) of which persisted beyond 3 months, prompting angiographic evaluation. In 2 patients the endoleak was related to a graft-graft or graft-arterial junction. One was from the endograft terminus in the common iliac artery and was successfully embolized, along with its outflow lumbar artery. The other required placement of an additional endograft component across a leaking graft-graft junction to successfully exclude the aneurysm. The remaining six endoleaks were due to collateral flow through the aneurysm sac. In 4 cases this was lumbar to lumbar flow fed by hypogastric artery collaterals to the inflow lumbar artery. In the remaining 2 patients the endoleak was found to be due to flow between a lumbar and inferior mesenteric artery. Resolution of the endoleak by coil embolization of the feeding hypogastric artery branch in 1 patient was unsuccessful due to rapid recruitment of another hypogastric branch. Two of the six collateral flow endoleaks have resolved spontaneously without treatment, while the remaining cases have been followed up without evidence of aneurysm expansion.

CONCLUSION

Systematic postoperative surveillance facilitates proper diagnosis and treatment of endoleaks. This involves serial CT scans to detect the presence of endoleaks, followed by angiography to determine their etiology and guide treatment, if clinically indicated.

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.

Feasibility of endovascular repair of abdominal aortic aneurysms with local anesthesia with intravenous sedation

PURPOSE

Local anesthesia has been shown to reduce cardiopulmonary mortality and morbidity rates in patients who undergo selected peripheral vascular procedures. The efforts to treat abdominal aortic aneurysms (AAAs) with endovascular techniques have largely been driven by the desire to reduce the mortality and morbidity rates as compared with those associated with open aneurysm repair. Early results have indicated a modest degree of success in this goal. The purpose of this study was to investigate the feasibility of endovascular repair of AAAs with local anesthesia.

METHODS

During a 14-month period, 47 patients underwent endovascular repair of infrarenal AAAs with local anesthesia that was supplemented with intravenous sedation. Anesthetic monitoring was selective on the basis of comorbidities. The patient ages ranged from 48 to 93 years (average age, 74.4 +/- 9.8 years). Of the 47 patients, 55% had significant coronary artery disease, 30% had significant chronic obstructive pulmonary disease, and 13% had diabetes. The average anesthesia grade was 3.1, with 30% of the patients having an average anesthesia grade of 4. The mean aortic aneurysm diameter was 5.77 cm (range, 4.5 to 12.0 cm). All the implanted grafts were bifurcated in design.

RESULTS

Endovascular repair of the infrarenal AAA was successful for all 47 patients. One patient required the conversion to general anesthesia to facilitate the repair of an injured external iliac artery via a retroperitoneal approach. The operative mortality rate was 0. No patient had a myocardial infarction or had other cardiopulmonary complications develop in the perioperative period. The average operative time was 170 minutes, and the average blood loss was 623 mL (range, 100 to 2500 mL). The fluid requirements averaged 2491 mL. Of the 47 patients, 46 (98%) tolerated oral intake and were ambulatory within 24 hours of graft implantation. The patients were discharged from the hospital an average of 2.13 days after the procedure, with 87% of the patients discharged less than 48 hours after the graft implantation. Furthermore, at least 30% of the patients could have been discharged on the first postoperative day except for study protocol requirements for computed tomographic scanning at 48 hours.

CONCLUSION

This is the first reported series that describes the use of local anesthesia for the endovascular repair of infrarenal AAAs. Our preliminary results indicate that the endovascular treatment of AAAs with local anesthesia is feasible and can be performed safely in a patient population with significant comorbidities. The significant potential advantages include decreased cardiopulmonary morbidity rates, shorter hospital stays, and lower hospital costs. A definitive evaluation of the benefits of local anesthesia will necessitate a direct comparison with other anesthetic techniques.

Access to the vascular system for endovascular procedures: techniques and indications for percutaneous and open arteriotomy approaches

The ability to reliably gain access to the vascular system is fundamental to the performance of all endovascular diagnostic and therapeutic procedures. Competence with a variety of different access sites and techniques is essential if one is to be able to address the full spectrum of vascular disease and diversity of clinical circumstances. Although open surgical access is sometimes indicated, most endovascular procedures can and should be performed percutaneously, because this is the least invasive technique. Understanding the advantages, risks, and potential pitfalls of the various approaches influences the site of access chosen and whether a percutaneous or open arteriotomy technique is used. Furthermore, this knowledge permits efforts to minimize attendant risks and facilitates recognition of problems when they do occur. The net result is a procedure unspoiled by failure to gain access or avoidable access site complications.

Local anesthesia for infrainguinal arterial reconstruction

PURPOSE

Perioperative cardiac complications occur in 4% to 6% of patients undergoing infrainguinal revascularization under general, spinal, or epidural anesthesia. The risk may be even greater in patients whose cardiac disease cannot be fully evaluated or treated before urgent limb salvage operations. Prompted by these considerations, we investigated the feasibility and results of using local anesthesia in these high-risk patients.

METHODS

From January 1, 1994, through August 30, 1996, 86 infrainguinal reconstructions were performed under local infiltration anesthesia (0.5% or 1.0% lidocaine). Supplementary intravenous sedation with propofol or other agents was given as needed for patients comfort. Most patients had arterial lines but Swan Ganz catheters were used infrequently. Postoperatively, continuous electrocardiographic monitoring was continued in the intermediate or intensive care units. Patients ranged in age from 37 to 86 years (mean 68 +/- 12); 47% were diabetic, 69% had severe coronary artery disease, and 14% had end-stage renal disease.

RESULTS

Operations included 7 femoral-femoral, 21 femoral-popliteal, 16 femoral-tibial and 13 popliteal-tibial bypass grafts, 9 pseudoaneurysms, and 20 distal graft revisions (+/- thrombectomy). Autogenous vein was used in eight of the femoral-popliteal and all of the femoral-tibial and popliteal-tibial bypass grafts. There were two postoperative deaths. One patient died of a stroke (1.2%) on postoperative day (POD) 2 and one died on POD 27 of unknown cause. Two other (2%) patients had nonfatal subendocardial myocardial infarctions. Conversion to general anesthesia was required in four (5%) operations, three because patients became agitated and one because a long segment of vein had to be harvested from the opposite leg. Otherwise, patients tolerated the procedures well and postanesthetic recovery problems were minimized.

CONCLUSIONS

Limb salvage operations can be done under local anesthesia with acceptable complication rates. In selected patients with high-risk coronary artery disease, local anesthesia has theoretic and practical advantages and should be considered an alternative to general or regional anesthesia.

Prevalence and distribution of calf vein thrombosis in patients with symptomatic deep venous thrombosis: a color-flow duplex study

PURPOSE

This retrospective study was performed to identify the patterns of calf vein thrombosis in patients in whom deep vein thrombosis (DVT) was suspected and to better define the role of color-flow duplex scanning (CDS) in the evaluation of this patient population.

METHODS

Over a recent 9-month period, we reviewed the vascular laboratory charts of 540 symptomatic patients (696 limbs) who underwent CDS for clinically suspected acute DVT. Patients who had a previous episode of DVT were excluded.

RESULTS

CDS satisfactorily visualized all three paired calf veins in 655 of the limbs (94%). Inadequate scans (n = 41) were attributed to edema in 29, excessive calf size in eight, and anatomic inaccessibility in four. Peroneal veins were the most difficult to visualize (n = 29), followed by posterior tibial (n = 10) and anterior tibial (n = 9) veins. CDS identified acute DVT in 159 of 655 limbs (24%) that had adequate scans. Calf vein thrombi were detected in 110 of the 655 limbs (17%) and in 69% of the 159 limbs with DVT. Clots were confined to the calf veins in 53 limbs with DVT (33%). Isolated calf vein thrombi were found in 45% of outpatient limbs and in 27% of inpatient limbs with DVT. The peroneal (81%) and posterior tibial veins (69%) were more frequently involved (p < 0.001) than the anterior tibial veins (21%). In limbs with calf DVT, the prevalence of thrombosis isolated to the peroneal and posterior tibial veins was similar (37% and 25%, respectively); no limb had an isolated anterior tibial DVT (p = 0.02).

CONCLUSION

CDS is a reliable method for evaluating calf veins for DVT. Calf vein thrombosis is common in patients who have acute DVT and often occurs as an isolated finding. The peroneal and posterior tibial veins are involved in the majority of cases; thrombi occur much less frequently in the anterior tibial veins. We conclude that CDS should be the noninvasive method of choice for the initial evaluation of patients in whom DVT is suspected, and we recommend that calf veins should always be studied but that routine scanning of the anterior tibial veins may not be necessary.

Determinants of success of color-flow duplex-guided compression repair of femoral pseudoaneurysms

BACKGROUND

Ultrasonography-guided compression repair is reported to be effective therapy for femoral pseudoaneurysms that develop after catheterization procedures. This study summarizes our experience with color-flow duplex-guided repair of these lesions.

METHODS

A retrospective chart review of all patients who underwent this procedure was undertaken, with statistical analysis to identify factors associated with success.

RESULTS

Compression repair of 69 pseudoaneurysms was attempted. Pseudoaneurysms developed after therapeutic catheterization in 48 patients and after diagnostic procedures in 21. Sites of arterial puncture were the common femoral artery in 59 patients and the superficial femoral or profunda femoris arteries in 10. Diameters of the pseudoaneurysms ranged from 3 to 60 mm (mean, 28 mm). Compression was attempted at a mean of 5 days (range, 1 to 21 days) after catheterization. Compression produced complete thrombosis of the pseudoaneurysm at the initial attempt in 43 (62%) of 69 patients. With repeated attempts the ultimate success was 47 (68%) of 69. Success was achieved in 44 (75%) of 59 common femoral pseudoaneurysms but in only 3 (30%) of 10 superficial femoral or profunda femoris lesions (p = 0.009). Anticoagulation, sheath size, pseudoaneurysm chamber size, and time between catheterization and compression were not significantly different between lesions that were successfully compressed and those that were not. No ischemic or embolic complications were observed.

CONCLUSIONS

Color-flow duplex-guided compression repair can be safely attempted as the initial therapy for all uncomplicated pseudoaneurysms arising from the common femoral artery after catheterization, with the expectation of success in most.

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.

Incorporation of endovascular training into a vascular fellowship program

BACKGROUND

Despite expanding indications for endovascular therapy of peripheral vascular disease, vascular surgeons have largely remained bystanders in the use of this form of treatment for the disease, which is the focus of their profession. Lack of access to training in endovascular techniques is a major obstacle to increasing involvement by vascular surgeons. This paper reports our experience in the endovascular training of vascular surgical fellows without the involvement of radiologists.

METHODS

The results of vascular surgery fellows receiving instruction in endovascular diagnostic and therapeutic procedures from vascular surgery faculty were reviewed.

RESULTS

Endovascular training of vascular surgery fellows exceeded the case levels recommended by all involved societies. A diverse case mix of 355 endovascular diagnostic procedures were performed with a major complication rate of 0.3% and no procedure-related deaths. Two hundred six endovascular interventions were performed, with an initial technical success rate of 96.6%, a 30-day success rate of 93%, no major complications, and an overall intervention-related mortality rate of less than 1%.

CONCLUSIONS

Vascular surgery fellows can receive endovascular training by vascular surgery faculty without the involvement of radiologists and can do so with acceptable success and complication rates. This experience is sufficient to qualify them to perform and teach endovascular therapy in their future practices.

Detection of total occlusion, string sign, and preocclusive stenosis of the internal carotid artery by color-flow duplex scanning

BACKGROUND

Stroke prevention depends on the accurate differentiation of surgically treatable preocclusive lesions from total occlusions of the internal carotid artery. This prospective study was undertaken to review the accuracy of colorflow duplex scanning for identifying carotid string signs, focal preocclusive lesions (95% to 99% stenoses), and total occlusion of the internal carotid artery.

MATERIALS AND METHODS

Over an 18-month period, 4,362 patients underwent color-flow duplex scanning of the carotid arteries. Angiograms of 596 internal carotid arteries were available for comparison with the duplex scan findings. Total occlusion was diagnosed by the absence of flow in internal carotid arteries visualized on B-mode scanning. Preocclusive lesions were identified by a trickle of flow in the vessel lumen.

RESULTS

Of 65 color-flow duplex scans that predicted total occlusion, 64 (98%) were confirmed by angiography. The negative predictive value for total occlusion was 99%. Twenty-six (87%) of 30 string signs and focal 95% to 99% stenoses were correctly identified. Color-flow scanning prediction of preocclusive lesions was accurate in 84% of 31 cases. Low velocities in the internal carotid artery were usually associated with a string sign, and high velocities with a focal preocclusive lesion.

CONCLUSIONS

Color-flow duplex scanning accurately differentiates between stenotic and totally occluded internal carotid arteries. Identification of preocclusive lesions is not as accurate but the results are promising. Arteriographic confirmation of duplex scan findings is necessary only when scans are equivocal.

Evolution of carotid endarterectomy in two community hospitals: Springfield revisited--seventeen years and 2243 operations later

PURPOSE

The purpose of this study was to evaluate and update the results of carotid endarterectomy (CEA) in two community hospitals over a 17-year period and to determine whether there had been any reduction in the unacceptably high incidence of complications previously reported from these same two hospitals.

METHODS

We retrospectively reviewed the records of 1981 patients who underwent 2243 CEAs from July 1976 to November 1993.

RESULTS

There were 36 operative deaths (1.6%) and 120 operative strokes (5.3%), for a combined stroke-mortality rate of 6.3%. The mortality, stroke, and combined stroke-mortality rates all decreased significantly (p < 10(-5)) compared with the rates reported in the original study (6.6%, 14.5%, and 21.1%, respectively). Nonfatal stroke rates decreased significantly for patients diagnosed with asymptomatic carotid artery disease, 18.2% to 2.9% (p = 0.04); transient ischemic attacks, 17.8% to 3.9% (p < 10(-6)); and prior stroke, 15.2% to 8.0% (p = 0.04). Improvement in combined stroke-mortality rates occurred for all operative indications, but was significant only in the transient ischemic (p < 10(-8)) and prior stroke groups (p = 0.00002). Surgical experience varied, with 31 surgeons performing one to 236 CEAs. Although results were not significantly correlated with individual operative activity, 10 surgeons who performed more than 12 CEAs per year had a statistically lower incidence of operative stroke (4.1%) compared with 21 surgeons who performed fewer procedures (7.2%) (p = 0.009). The incidence of stroke (2.7%) and the combined stroke-mortality rate (3.7%) of surgeons with additional vascular training was superior to the stroke rate (6.8%) and combined stroke-mortality rate (7.9%) of surgeons who did not (p = 0.0014 and p = 0.0006); but several surgeons in the latter group had results that were comparable to those of the vascular group.

CONCLUSIONS

Although overall operative complication rates in these two community hospitals have declined dramatically compared with previously reported results, they are still not optimal and probably will remain high as long as individual surgeons with high complication rates continue to perform CEAs.

The natural history of moderate (50% to 79%) internal carotid artery stenosis in symptomatic, nonhemispheric, and asymptomatic patients

PURPOSE

This study was undertaken to determine the incidence of disease progression of moderate (50% to 79%) internal carotid artery stenosis in patients with symptoms, patients with nonhemispheric symptoms, and symptom-free patients and to define the risk of development of new neurologic events in each group.

METHODS

Over a 6-year period, 272 patients with moderate internal carotid artery stenoses were monitored for a mean of 44 months with color-flow duplex scanning (CFS). At the time of the initial scan, 142 patients were symptom free, 87 had experienced transient ischemic attacks, amaurosis fugax, or mild strokes, and 43 had ill-defined nonhemispheric symptoms. The average number of follow-up scans was 2.4 per patient (range 1 to 11).

RESULTS

During follow-up, 23 (26%) of the patients with symptoms, 17 (40%) of the patients with nonhemispheric symptoms, and 30 (21%) of the symptom-free patients had development of additional neurologic symptoms. Life-table comparison of ipsilateral ischemic events showed a significantly (p = 0.03) higher cumulative rate in the symptomatic group (20%) than in the asymptomatic group (7%) at 2 years. Mean annual stroke rates were 6% and 2% in patients in the symptomatic and asymptomatic groups, respectively. None of the patients in the nonhemispheric group had a stroke within 4 years of the initial study. Disease progression occurred in 16% of the patients. In the asymptomatic group, ipsilateral stroke occurred more frequently (p = 0.0001) in patients with disease progression (25%) than in patients with stable lesions (1%). CFS detected disease progression in 19 (79%) of 24 patients before the artery occluded or stroke occurred. In patients with symptoms, stroke was more frequent (p = 0.02) in patients with six or more risk factors (29%) than in those with five or fewer risk factors (7%).

CONCLUSION

Although the risk of stroke is less in patients with moderate stenosis than it is in patients with severely stenotic lesions, symptom-free patients with advancing disease and patients with symptoms and multiple risk factors are at increased risk for development of neurologic events. These findings support the use of CFS to monitor patients with carotid artery disease and suggest that a more aggressive surgical approach may be indicated in selected patients with moderate carotid artery stenosis.

Carotid endarterectomy without angiography: is color-flow duplex scanning sufficient?

BACKGROUND

This study was designed to determine whether clinical evaluation and color-flow duplex scanning (CFS) alone provide enough information for patients to undergo carotid endarterectomy (CEA) safely without preoperative cerebral angiography and to assess the appropriate role of CFS in the evaluation of extracranial carotid artery disease.

METHODS

During a 31-month period 167 patients (114 symptomatic and 53 asymptomatic) underwent CFS and angiography during evaluation for CEA. One hundred fifty-three patients were studied retrospectively, and 14 were studied prospectively. Data were reviewed to determine whether cerebral angiography added information not provided by duplex findings and, if so, did the results alter clinical management.

RESULTS

Of the 167 patients studied, 149 underwent CEA and 18 were treated medically. Results of the two diagnostic modalities agreed perfectly in 82% of the patients, with 99% of the stenoses estimated by CFS being classified within one category of those measured with angiography. The sensitivity of CFS for detecting greater than 50% diameter-reducing stenoses of the internal carotid artery was 98%, and the positive predictive value was 99%. For detecting greater than 80% stenoses, CFS had a sensitivity of 84% and a positive predictive value of 95%. Clinical management was altered by angiographic findings in only seven patients (4%). False-positive results (n = 5) were due to poor scanning technique or interpreter error (n = 2), anatomic variations (n = 2), and unknown cause (n = 1). All false-negative results (n = 2) were due to poor scanning technique.

CONCLUSIONS

Ninety-six percent of the patients in this study would have received appropriate clinical management based on neurologic history and the results of CFS alone. Our results indicate that CFS is sufficient for determining the need for surgery in patients being considered for CEA and can supplant cerebral angiography in nearly all clinical circumstances.

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.

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 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.

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.

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.

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.

Internal carotid artery occlusion: operative risks and long-term stroke rates after contralateral carotid endarterectomy

BACKGROUND

To determine the short- and long-term benefits of carotid endarterectomy (CEA) contralateral to an occluded internal carotid (ICA), we reviewed our experience since 1976.

METHODS

In 66 (13.8%) of 478 patients undergoing 544 CEAs, the contralateral ICA was occluded. Mean follow-up was 50.1 months (range, 1 to 165 months). Complete follow-up was available in 83.0% of patients.

RESULTS

Operative death occurred in one (1.5%) of 66 patients with contralateral occlusion and six (1.3%) of 478 patients without contralateral occlusion (p = 0.99). Operative strokes occurred in two (3.0%) of 66 patients with contralateral occlusion and 14 (2.9%) of 478 without contralateral occlusion (p = 0.99). Life-table stroke-free rates at 1, 3, 5, and 8 years were 96.8%, 93.0%, and 93.0% in patients with contralateral occlusion and 95.9%, 94.2%, 91.1%, and 88.0% in patients without contralateral occlusion (p = 0.36). Five- and 8-year stroke-free rates were 100% and 100% in the asymptomatic subgroup with occlusion, 95.9% and 92.2% in the asymptomatic subgroup without occlusion (p = 0.45), 91.2% and 91.2% in the symptomatic subgroup with occlusion, and 89.7% and 86.8% in the symptomatic subgroup without occlusion (p = 0.47). Life-table survival rates at 5 and 8 years were 72.5% and 56.0% in patients with contralateral occlusion and 81.8% and 69.0% in patients without contralateral occlusion (p = 0.15).

CONCLUSIONS

CEA performed in patients with and without symptoms with a contralateral ICA occlusion produces short- and long-term mortality and stroke morbidity rates comparable to those of similar patients without contralateral ICA occlusion. The indications for CEA in patients with contralateral ICA occlusion should not differ from those applied to patients without contralateral occlusion.

Carotid endarterectomy: operative risks, recurrent stenosis, and long-term stroke rates in a modern series

To determine whether carotid endarterectomy (CEA) safely and effectively maintained a durable reduction in stroke complications over an extended period, we reviewed our data on 478 consecutive patients who underwent 544 CEA's since 1976. Follow-up was complete in 83% of patients (mean 44 months). There were 7 early deaths (1.3%), only 1 stroke related (0.2%). Perioperative stroke rates (overall 2.9%) varied according to operative indications: asymptomatic, 1.4%; transient ischemic attacks (TIA)/amaurosis fugax (AF), 1.3%; nonhemispheric symptoms (NH), 4.9%; and prior stroke (CVA), 7.1%. Five and 10-year stroke-free rates were 96% and 92% in the asymptomatic group, 93% and 87% in the TIA/AF group, 92% and 92% in the NH group, and 80% and 73% in the CVA group. Late ipsilateral strokes occurred infrequently (8 patients, 1.7%). Late deaths were primarily cardiac related (51.3%). Stroke-free rates were significantly (p less than 0.0001) greater than stroke-free survival rates, confirming a non-stroke related cause for late death. Restenoses greater than 50% according to duplex scanning developed in 13%, most (67%) within 2 years after CEA. Most of these (77%) were asymptomatic, and only 0.3% (1 patient) presented with a permanent neurologic deficit. The results of carotid endarterectomy are superior to those of optimal medical management in symptomatic and asymptomatic patients in terms of long-term stroke prevention. When low perioperative stroke mortality/morbidity rates are achieved, carotid endarterectomy is justified for treatment of patients with carotid bifurcation disease.

Identifying total carotid occlusion with colour flow duplex scanning

A major limitation of conventional duplex scanning is its inability reliably to differentiate severe stenosis from total occlusion of the internal carotid artery (ICA). Colour flow duplex scanning (CFS) facilitates the identification of internal and external carotid arteries, enables simultaneous evaluation of flow in multiple vessels in longitudinal and transverse views, and allows more accurate assessment of very low Doppler-shift frequencies with new "slow-flow" software technology. From July 1987 to January 1991, 9731 ICAs (4866 patients) were evaluated with CFS. Arteriography was performed in 483 of these patients (959 ICAs), and the results of the two studies were compared. Colour flow scanning was highly accurate in differentiating total occlusion from carotid stenosis. Eighty-two of 87 totally occluded ICAs were detected (sensitivity 94%) and 873 of 878 patient arteries were properly identified (specificity 99%). Positive and negative predictive values were 93 and 99%, respectively. False positive results (n = 6) were due to interpreter error (n = 4) and poor scanning technique (n = 2). All false negative results (n = 5) were the result of interpreter error. During the last 24 months of the study, no false positive or false negative results were detected, giving an accuracy of 100%. We conclude that CFS offers distinct advantages in the diagnosis of carotid occlusion, thereby overcoming the limitations of conventional duplex scanning in distinguishing total occlusion of the ICA from less severe disease, and is the method of choice for evaluating the carotid bifurcation.

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.

Clinical follow-up and progression of carotid atherosclerosis determined by duplex scanning in patients suffering from TIA

We investigated the clinical outcomes and the progression of the internal carotid arterial lesions of a group of patients presenting with hemispheric TIAs. The cumulative frequency of TIAs during a mean follow-up period of 40 +/- 14 months was 14%, and no relationship was found between new TIAs and the presence of known cardiovascular risk factors or plaque characteristics as determined by duplex scanning. With the exception of one patient who died of stroke, none of the patients developed a permanent neurologic deficit. The cumulative death rate was 6.5%; myocardial infarction was the most common cause (3 out of 7). Anatomic progression of plaques was determined by duplex scanning in 22% of the internal carotid arteries. No relationship between progression of these plaques and the development of new TIAs was evident. We conclude that, in this group of patients, TIAs do not inevitably lead to stroke and that TIAs are not predictable based on risk factors or plaques characteristics.

Does color-flow imaging improve the accuracy of duplex carotid evaluation?

To determine whether color-flow imaging enhances the accuracy of noninvasive carotid evaluation, the results of carotid duplex examinations from two laboratories, one with color-flow and the other with standard duplex imaging were compared. The techniques used by both laboratories were identical. All studies were interpreted by one of the authors, using the same criteria. From October 1988 through December 1989, 307 internal carotid arteries were evaluated with both color-flow imaging and standard angiography; and 206 underwent routine duplex scanning and angiography. Perfect agreement between test and angiographic results was significantly better with color-flow (86.6%) than with conventional duplex scanning (79.6%), p = 0.034 (t test for independent samples). Significantly fewer vessels were over classified by one category with color-flow (8.5%) than with routine duplex scanning (16.5%), p = 0.006. However, no difference was found in the number under-classified by one category (4.5% vs 3.4%), p = 0.5. Although these data support the accuracy of both modalities, there appears to be a trend toward improved results with the newer method. We attribute this to more precise placement of the pulsed Doppler sample volume afforded by the color-flow image.

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.

Initial experience with color-flow duplex scanning of infrainguinal bypass grafts

Seventy-eight infrainguinal grafts were evaluated by means of color-flow duplex imaging to demonstrate its utility in the routine surveillance of leg grafts as well as in the evaluation of grafts in which a problem is already suspected. Stenoses were identified in 15 (20%) of 76 grafts evaluated for screening purposes. Seven of these had confirmatory arteriograms, and five were revised. The remaining eight grafts with suspected stenoses were followed without angiography, and four (50%) subsequently failed. Only two (3.3%) of 61 grafts with normal scan outcomes have thrombosed. Fistulas were identified in 12 (37%) of 32 in situ grafts evaluated. Nine grafts with previously suspected problems based on decreased ankle-brachial indexes were scanned, and an explanation was found, confirmed by angiogram, and corrected in six. Detection of unsuspected stenoses in five grafts requiring revision and four grafts that later thrombosed without revision, as well as identification of fistulas in 37% of in situ grafts, confirms the importance of color-flow imaging as a screening tool.

Contralateral internal carotid artery stenosis or occlusion: pitfall of correct ipsilateral classification--a study performed with color-flow imaging

The records of 183 patients who had undergone color-flow imaging of the extracranial carotid arteries and subsequent bilateral cerebral arteriography were reviewed to determine whether contralateral carotid arterial disease adversely affects the accuracy of duplex scanning by increasing the velocity of flow in the ipsilateral artery. In 83 arteries the contralateral internal carotid artery had a diameter reduction greater than or equal to 80%; in the remaining 283, the contralateral artery was less severely diseased. Noninvasive findings correlated less well with arteriography in the group with contralateral disease (k = 0.69 +/- 0.06) than in the group with less severe contralateral stenosis (k = 0.78 +/- 0.03), and the incidence of false-positive errors was significantly (p = 0.02) higher (18% vs 7%). For all categories of ipsilateral stenosis, the mean peak systolic and end-diastolic velocities were elevated in the group with severe contralateral disease. This effect was most evident in the 50% to 79% diameter reduction category, especially in reference to the end-diastolic velocity (p = 0.2). However, the data correlating velocity with diameter reduction were widely scattered, indicating that the effect of contralateral disease is inconsistent. We conclude that severe disease of the contralateral carotid artery can lead to overreading ipsilateral disease and that velocity determinations should be interpreted cautiously under such circumstances.

Use of color-flow imaging technique in carotid artery disease

Color-flow imaging of the cervical vasculature has several distinct advantages compared with conventional duplex scanning: it facilitates identification of the carotid artery, its bifurcation, branches, and other cervical vessels, especially the vertebral arteries; decreases the time required for longitudinal surveys; aids in the recognition of kinks, coils, and occluded vessels; evaluates flow simultaneously in large areas and multiple vessels; and focuses attention on sites of flow disturbance. Although many problems remain, color-flow imaging represents a powerful new tool for the diagnosis and physiologic assessment of extracranial cerebrovascular disease.

Ultrasonic screening for the detection of abdominal aortic aneurysms

Detection of aortic aneurysms before they rupture is imperative if the mortality rate from this disease is to be reduced. Although large aneurysms frequently are palpable, small aneurysms--especially in obese patients--are seldom recognized on physical examination. Ultrasound, which is noninvasive, relatively inexpensive, and nearly 100 per cent accurate in identifying the presence or absence of aneurysms, is well suited to screening. In high-risk populations (patients over the age of 50 with coronary artery or peripheral vascular disease), ultrasonic screening is probably cost-effective.

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.

Carotid stump syndrome: a colour-coded Doppler flow study

Colour-coded Doppler flow imaging (angiodynography) was performed on 29 patients with 30 internal carotid artery occlusions. Large internal carotid stumps were revealed as intravascular cul-de-sacs demonstrating vortices of blue flow reversal. Large carotid stumps or significant external carotid stenoses were present in nine patients (9 arteries). Such patients were significantly more likely to develop symptoms of cerebral ischaemia during follow up which averaged 18 months (P = 0.016; Fisher exact). These results support the concept of embolisation from the carotid bifurcation (residual stump or external stenosis) as a cause of episodic cerebral ischaemia following internal carotid occlusion. Angiodynography may prove to be a useful tool for selecting appropriate patients for treatment.

Prevalence of asymptomatic carotid disease: results of duplex scanning in 348 unselected volunteers

The risk of stroke in patients with asymptomatic carotid disease appears to be related to the presence of a high-grade stenosis. To determine the prevalence of such lesions, duplex scanning was performed on 348 unselected volunteers without symptoms who attended hospital-sponsored health fairs. There were 209 women and 139 men whose ages ranged from 24 to 91 years. Risk factors included hypertension (37%), diabetes (8%), and smoking (23%). One hundred seven subjects (31%) had evidence of extracranial carotid artery disease, 13 (4%) with greater than 50% stenosis, and three (1%) with greater than 80% stenosis of the internal carotid artery. Bilateral disease was present in 50 patients. Disease prevalence and severity were significantly correlated with age (p less than 0.001) and hypertension (p less than 0.01) but not with diabetes or smoking. The incidence of disease was similar in men and women. Although carotid plaques are common in people older than 50 years of age who do not have symptoms, the prevalence of high-grade stenosis--even in the elderly hypertension population--is low, casting doubt on the cost-effectiveness of generalized screening.

Noninvasive assessment of lower extremity arterial disease

Although angiography is the accepted "gold standard" for demonstrating the presence of arterial occlusive disease, it is less accurate for grading the associated hemodynamic consequences and is prohibitively invasive and expensive to be used as a first-line investigation. Currently available noninvasive tests allow not only for the detection of perfusion abnormalities, but for an appreciation of their severity as well as their likely location. This information is invaluable for predicting the need for revascularization, guiding the choice of reconstructive procedure, and predicting the likelihood of healing of amputation wounds and ischemic lesions. Although some obstructive lesions are easily detected, others require more in-depth testing to reveal and quantify. Consequently, a thorough understanding of available noninvasive diagnostic modalities, including both their capabilities as well as their pitfalls, is paramount to the effective practice of vascular surgery.

Buttock claudication from isolated bilateral internal iliac arterial stenoses

An unusual case is reported of severe buttock claudication in a woman with normal ankle systolic pressures after exercise, for which the cause was eventually found to be isolated bilateral hypogastric arterial stenosis. Although a normal ankle pressure response to exercise usually rules out vascular obstruction in patients with symptoms suggestive of intermittent claudication, the diagnosis of isolated hypogastric arterial disease should be entertained when a neurogenic or orthopedic explanation can be excluded.

Relationship of venous reflux to the site of venous valvular incompetence: implications for venous reconstructive surgery

To evaluate the relationship of the site of venous valvular incompetence to the severity of venous reflux, legs of 71 patients with suspected chronic venous insufficiency were evaluated with Doppler ultrasonography and photoplethysmography. A venous recovery time (VRT) of less than 20 seconds after calf muscle exercise was considered indicative of significant reflux. Average VRTs were brief in 15 legs with stasis changes (10 +/- 7 seconds), longer in 42 legs with edema (26 +/- 23 seconds), and normal in 64 asymptomatic legs (37 +/- 24 seconds) and 16 legs with pain (53 +/- 19 seconds). Average VRTs in limbs with incompetent saphenous veins were abnormal. In limbs with competent superficial veins, only those with incompetent distal deep veins (popliteal and posterior tibial) had abnormal VRTs (14 +/- 10 seconds). VRTs in limbs with no detectable valvular incompetence and in those with incompetence limited to the proximal deep veins (common and superficial femoral) were normal (47 +/- 23 and 42 +/- 27 seconds, respectively). When superficial veins were incompetent, an ankle tourniquet normalized VRTs in 63% of legs with proximal deep venous incompetence and in only 33% of legs with distal deep venous incompetence. It is concluded that venous reflux is largely determined by saphenous and distal deep valvular function and that competence of the proximal valves has little effect. Decreased venous reflux would not be expected after proximal valvular reconstruction.

Chylous ascites after abdominal aortic aneurysmectomy: successful management with a peritoneovenous shunt

Postoperative chylous ascites is a rare complication of aortic aneurysmectomy. Although increasing numbers of abdominal aortic aneurysms are being resected annually, there have been only eight previously reported cases of chylous ascites after this operation. This article describes the ninth case of postoperative chylous ascites after abdominal aortic aneurysm resection and emphasizes the value of management with peritoneovenous shunting.

Prevalence of extracranial carotid artery disease: a survey of an asymptomatic population with noninvasive techniques

To investigate the prevalence of internal carotid arterial stenosis in an unselected asymptomatic population over 50 years of age, 102 volunteers from one church congregation were studied with ultrasonic arteriography, spectral analysis, and ocular pneumoplethysmography. Fifty subjects were 50 to 59 years old; 33 were 60 to 69 years of age; and 19 were older than 70 years. Forty-five were men and 57 were women. Risk factors included diabetes mellitus (4%), heart disease (9%), hypertension (24%), peripheral vascular disease (20%), and smoking (46%). Disease was found in 11 subjects (10.8%). Of the 204 internal carotid arteries, 13 (6.4%) were abnormal. Two vessels had 20% diameter stenosis; four had stenoses of 20% to 39%; five had stenoses of 40% to 59%; one had a stenosis of 60% to 79%; and one was occluded. Stenoses greater than 40% occurred in 4% of the 50 to 59 years of age group, 6% of the 60 to 69 years of age group, and 11% of the greater than 70 years of age group. Although the prevalence of carotid stenosis was increased in all subjects who had risk factors, only the association with heart disease reached statistical significance. These results indicate that carotid stenosis is present in an appreciable number of asymptomatic subjects over the age of 50 years and suggest that its prevalence is associated with age and other risk factors.