Biomedical subjects

D E Ramsey

Publications and source records attributed to D E Ramsey.

At least 19 recordsLinked to original sources

PubMed2000

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.

Female↗

PubMed2000

Clinical failure after percutaneous transluminal angioplasty of the superficial femoral and popliteal arteries.

OBJECTIVE: Anatomic patency after percutaneous transluminal angioplasty (PTA) of the superficial femoral and popliteal arteries does not guarantee clinical success. The aim of this report is to determine the causes of clinical failure after PTA. METHODS: The records of all patients who have undergone PTA of the femoropopliteal arterial segment by our vascular group were retrospectively reviewed. Only patients with complete records and at least one postprocedure clinical and anatomic assessment within the same 30-day time interval were included. Success was defined according to the Society for Vascular Surgery/International Society for Cardiovascular Surgery Ad Hoc Subcommittee on Reporting Standards for Endovascular Procedures. Anatomic cumulative patency and clinical success were calculated according to life table analysis on an intent-to-treat basis. RESULTS: We identified 85 patients who met inclusion criteria. We treated 112 lesions with an average stenosis of 80% +/- 16% and lesion length of 2.3 +/- 1.8 cm. Technical failure occurred in six (5.4%) of 112 lesions. Cumulative clinical success was 69% at 1 year, 54% at 2 years, 49% at 3 years, and 40% at 4 years. Anatomic patency was 74% at 1 year, 62% at 2 years, 57% at 3 years, and 52% at 4 years. There were 45 clinical failures; of these, twenty-seven (60%) occurred in conjunction with anatomic failure. Anatomic failure was due to restenosis in 12 patients (44%), occlusion in eight patients (30%), and restenosis with progression of disease in six patients (22%). Anatomic failure at the time of the procedure occurred in one patient (4%). Clinical failure occurred despite anatomic patency in the remaining 18 patients (40%). Etiology for clinical failure in this latter group included progression of disease within the treated vessel in 12 patients (67%), iliac disease in three patients (17%), tibial disease in two patients (11%), and bypass graft failure in one patient (5%). Fifty percent of all 45 clinical failures were successfully treated with supplemental percutaneous procedures. CONCLUSION: A PTA is an acceptable therapeutic option for the treatment of focal occlusive disease of the femoropopliteal arterial segment. Most clinical failures were due to anatomic failure, but a significant number occurred despite patency at the PTA site. Although primary clinical success rates were inferior to surgical bypass graft, supplemental PTA was possible in 50% of patients. Repeat percutaneous treatment may extend the interval of clinical success and may obviate the need for surgical bypass graft.

Angioplasty, Balloon↗

PubMed1999

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.

Algorithms↗

PubMed1999

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.

Aortic Aneurysm, Abdominal↗

PubMed1999

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.

Aged↗

PubMed1998

Long-term patency rates, complications and cost-effectiveness of polytetrafluoroethylene (PTFE) grafts for hemodialysis access: a prospective study that compares Impra versus Gore-tex grafts.

Manufacturers of polytetraflouroethylene (PTFE) grafts used for chronic hemodialysis access describe specific advantages for their respective grafts, which presumably result in greater graft patency rates, reduced complications and decreased overall costs. There are few data available in the literature to support or contradict these alleged benefits. Therefore, this prospective study was undertaken to evaluate and compare patency rates, complications and costs between two of the leading brands of PTFE that are currently being marketed for use as hemodialysis access grafts. Totals of 190 primary PTFE grafts (100 Gore-tex (W. L. Gore and Associates, Flagstaff, AZ) and 90 Impra (C. R. Bard Inc., Tempe, AZ)) were implanted in 168 consecutive patients with end-stage renal disease. A policy of non-interventions was employed for patent grafts, as no attempt was made to assist primary patency. Grafts that occluded during follow-up underwent secondary revision to maintain patency. There was no difference in primary and secondary patency by life-table analysis between Gore-tex and Impra grafts at 2 years (P > 0.53 and P > 0.13, respectively). There was also no significant difference between Gore-tex and Impra in the number of days before the first thrombectomy or in the number of thrombectomies or revisions per graft (P > O.50). Likewise, the incidence of complications was similar between the two grafts. The cost of graft implantation and maintenance of patency was not significantly different between Gore-tex and Impra grafts. It is concluded that either graft can be used for hemodialysis access with similar expected outcomes for at least 2 years following implantation.

Arteriovenous Shunt, Surgical↗

PubMed1996

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.

Adult↗

PubMed1996

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.

Acute Disease↗

PubMed1996

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.

Angiography↗

PubMed1996

Validity of simple approach to scoring and standard setting for standardized-patient cases in an examination of clinical competence.

The results are disappointing, providing little support for the validity of the case-passing decisions based on this simple approach to scoring and standard setting. The case-passing decisions predicted what the case author intended for about only 73% or 74% of the students on average and, with agreement expected by chance removed, predicted what the case author intended for about only 25% of the students. Even with the use of the optimal pass/fail cutoffs and the dropping of students with ambiguous borderline global ratings, the case-passing decisions failed to agree with the case authors' global ratings for 15% to 30% of the students. The findings might be dismissed as simply due to low reliabilities of passing decisions and global ratings based on a single case. Although this concern would apply to intercase reliabilities, which would be subject to case specificity, the appropriate reliabilities here would seem to be intracase (i.e., intrarater), which should be fairly high (if they could be computed). Nevertheless, it seems reasonable to expect much better agreement between results of case scoring and of standard setting developed by the case author and the case author's global ratings of performance on that case, given that the case author might recall the checklist, assign a weight to each item, and so forth. Also, case-passing decisions would possibly agree more with global ratings of live or videotaped performances than with ratings of written summaries of performance; however, that question remains a challenge for further research. In conclusion, the study provides only weak evidence, at best, for the validity of the scoring and standard setting commonly used with SP assessment. The results do not undermine claims about the realism of the SP approach, however, nor do they call into question the standardization afforded by this method of assessing clinical competence. The results do raise serious concerns about this simple approach to scoring and standard setting for SP-based assessments and suggest that we should focus more on the observation and evaluation of actual student performance on SP cases in the development of valid scoring and standard setting.

Achievement↗

PubMed1995

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.

Aged↗

PubMed1995

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.

Angioplasty, Balloon↗

PubMed1995

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.

Aged↗

PubMed1995

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.

Aged↗

PubMed1994

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.

Blood Flow Velocity↗

PubMed1994

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.

Adult↗

PubMed1994

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.

Aged↗

PubMed1993

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.

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