Douglas B. Hood

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.

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.

Advances in the treatment of phlegmasia cerulea dolens

Phlegmasia cerulea dolens (PCD) is an uncommon, severe form of lower extremity deep venous thrombosis characterized by extremity swelling, cyanosis, and pain. Progression of the thrombotic process may result in extremity gangrene, amputation, and death. The relative value of specific therapeutic regimens in the treatment of this disease remains uncertain. Twelve patients, 9 females and 3 males, with PCD were treated during a 10-year period. Eighteen lower extremities were involved. Pre-existing conditions included malignancy (eight), postoperative state (four), diabetes (three), previous deep venous thrombosis (three), and hypercoagulation (two). Venous gangrene was present in four patients. All patients were treated initially with bedrest, fluid resuscitation, extremity elevation, and systemic high-dose heparin therapy. Five patients had complete resolution with this regimen alone. One patient required cessation of heparin therapy due to heparin-induced thrombocytopenia and developed gangrenous toes. Two patients whose condition failed to respond to heparin therapy underwent catheter-based delivery of urokinase with marked clinical improvement. Four patients, two with venous gangrene, died, three of whom had disseminated malignant disease. A significant percentage of patients with PCD will respond to extremity elevation, fluid resuscitation, and aggressive systemic anticoagulation therapy. Thrombolytic therapy selectively administered is beneficial in patients whose disease fails to respond promptly. Venous thrombectomy should be reserved for patients with contraindications to thrombolysis.

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.

Predictors of wound complications following major amputation for critical limb ischemia

OBJECTIVES For patients with end-stage critical limb ischemia (CLI) who have already suffered over an extended period of time, a major amputation that is free of wound complications remains paramount. Utilizing data from the American College of Surgeons, National Surgical Quality Improvement Program (ACS-NSQIP), the objective of this report was to determine critical factors leading to wound complications following major amputation. METHODS ACS-NSQIP was used to identify patients ≥ 50 years, with CLI, and having an ipsilateral below-(BKA) or above-knee amputation (AKA). The primary outcome was wound occurrence (WO) defined by affirmative findings of superficial infection, deep infection, and/or wound disruption. The secondary outcome was 30-day mortality. Following univariate analyses, a multiple logistic regression was performed to identify predictive factors. RESULTS Between January 1, 2005 and December 31, 2008, 4250 patients fulfilled inclusion criteria (2309 BKAs and 1941 AKAs). WOs were 10.4% for BKAs and 7.2% for AKAs. For BKAs, increasing elevation in international normalized ratio (INR) predicted more WOs (P = .008, odds ratio [OR] 1.5 for every integral increase in INR) as did age 50 to 59 compared with older patients (P = .002, OR 1.9). For AKAs, being a current smoker predicted more WOs (P = .0008, OR 1.8) as did an increasing body mass index (BMI) (P = .02, OR 1.3 for every 10 kg/m(2) increase in BMI). Mortality was 7.6% for BKAs and 12% for AKAs. Complete functional dependence was most predictive of mortality following AKA (P < .0001, OR 2.5). Medical comorbidities such as history of myocardial infarcation (MI) (OR 1.8), congestive heart failure (CHF, OR 1.6), and chronic obstructive pulmonary disease (COPD, OR 1.6) predicted mortality following BKA, while dialysis use (OR 2.4), CHF (OR 2.3), and COPD (OR 2.1) predicted mortality following AKA. CONCLUSIONS Wound occurrences and mortality rates after major amputation for CLI continue to be a prevalent problem. Normalization of the INR prior to BKA should decrease WOs. Heightened awareness in higher risk patients with improved preventive measures, earlier disease recognition, better treatments, and increased education remain critical to improving outcomes in an already stressed patient cohort.

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.

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.

Race Independently Impacts Outcome of Infrapopliteal Bypass for Symptomatic Arterial Insufficiency

The impact of racial background on the outcome of lower extremity revascularization is unknown because a majority of studies have a preponderance of white patients. The charts of patients between 1988 and 2004 requiring infrapopliteal lower extremity revascularization were reviewed. Life-table analyses, the Cox proportional hazards model, and log-rank test were used to calculate graft patency and limb salvage. Bypasses were performed on 236 limbs in 225 patients. Mean follow-up was 18 ± 1.5 months. Twenty-eight (12%) bypasses were performed on whites, 43 (18%) on African Americans, 148 (63%) on Hispanics, and 17 (7.2%) on patients of other races. African American race negatively correlated with primary-assisted patency (hazard ratio 2.9, P = .03), secondary patency (hazard ratio 3.64, P = .02), and limb salvage (hazard ratio 8, P = .006) compared with whites. African American race has a negative impact on the long-term outcome of infrapopliteal revascularization, regardless of disease stage or associated risk factors.

CURRENT TRENDS IN THE MANAGEMENT OF IATROGENIC CERVICAL CAROTID ARTERY INJURIES

This study was undertaken to elicit the opinion of experts regarding the management of iatrogenic injury to the carotid artery. A text questionnaire was transmitted by electronic mail to members of the Western Vascular Society concerning management of iatrogenic injury to the cervical carotid artery. Participants were asked to submit information regarding practice status and their preferred choices for the management of different clinical scenarios. The scenarios were: (1) large bore sheath (> 8.5F) cannulation of the carotid artery in anesthetized patients, (2) large bore sheath cannulation of the carotid artery in an awake patient, (3) delayed recognition of a misplaced sheath by > 4 hours, and (4) arterial puncture was recognized after only the entry needle (16-gauge) was introduced but before sheath insertion. Finally, the members were asked to comment on the management of abnormal findings on duplex scanning, such as intimal flap or pseudoaneurysm. A response rate of 42% was obtained (45/106 active members). Eighty-two percent of respondents had been in practice for longer than 10 years. Eighty-nine percent had seen this complication and 29% had cared for patients in whom subsequent neurologic deficit developed. The institutional incidence of such injury was 1-5 cases per year for 82% of respondents. Sixteen-gauge needle injury was managed by immediate removal and applied pressure by 98% of respondents. When large-bore sheath injury is recognized within 1 hour of insertion, 62% of respondents would remove the sheath and hold pressure, with or without obtaining a duplex ultrasound examination. However, if injury recognition was delayed for > 4 hours, 82% would proceed to surgery. Only 26% operated on asymptomatic carotid flap found on ultrasound, while the remaining 74% would base their decision on size and flow characteristics on ultrasound. The management of pseudoaneurysm differed significantly. Whereas 31% of respondents would manage this finding expectantly, 69% would proceed to surgery regardless of size or symptoms. Despite awareness of iatrogenic injury to the cervical carotid artery, the institutional incidence remains high. Two thirds of respondents would manage a misplaced sheath in the carotid artery nonoperatively if the injury was recognized immediately. However, if injury recognition was delayed for > 4 hours, the majority of respondents would remove the sheath surgically. While the management of intimal flap largely depended on size and flow characteristics, 69% of respondents would operate on a pseudoaneurysm regardless of size or symptoms. The results of this survey may serve as a guideline for the management of this potentially devastating injury.

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.