O. William Brown

Penetrating atherosclerotic ulcers of the aorta

PURPOSE This study investigates the natural history and optimal imaging modality of penetrating atherosclerotic ulcers of the aorta. METHODS We reviewed our experience with 29 penetrating ulcers in 18 patients. Computed tomography (17 patients), magnetic resonance imaging (nine patients), and aortography (five patients) were used for diagnosis and follow-up. Patients were typically elderly (average age 74 years) and had hypertension and coronary artery disease. Ulcers were most common in the distal descending thoracic aorta (31%) and were characterized by a discrete ulcer crater (100%) and thickened aortic wall (89%). Modes of presentation included chest or back pain in four patients, distal embolization in two patients, and abnormal chest radiography results in one; the remaining were incidental findings. RESULTS Follow-up was available in ten patients with 17 ulcers from 1 to 7 years. Recurrent pain occurred in two patients, recurrent embolization occurred in one patient, and seven patients remained symptom free. Progression to saccular pseudoaneurysm occurred in five ulcers, and fusiform aneurysm occurred in two ulcers. Two ulcers were associated with an increase in aortic diameter, and nine ulcers did not change. There were no cases of aortic dissection or rupture in the follow-up period. There were no deaths and only one patient underwent resection. CONCLUSION The natural history of penetrating atherosclerotic ulcers is one of progressive aortic enlargement, with saccular and fusiform aneurysms the result if follow-up is sufficient. Aortic dissection, aortic rupture, and embolization can also occur but are less common. Contrast-enhanced computed tomography is the primary imaging modality.

Progression of superficial venous thrombosis to deep vein thrombosis

PURPOSE We have evaluated the progression of isolated superficial venous thrombosis to deep vein thrombosis in patients with no initial deep venous involvement. METHODS Patients with thrombosis isolated to the superficial veins with no evidence of deep venous involvement by duplex ultrasound examination were evaluated by follow-up duplex ultrasonography to determine the incidence of disease progression into the deep veins of the lower extremities. Initial and follow-up duplex scans evaluated the femoropopliteal and deep calf veins in their entirety; follow-up studies were done at an average of 6.3 days, ranging from 2 to 10 days. RESULTS From January 1992 to January 1996, 263 patients were identified with isolated superficial venous thrombosis. Thirty (11%) patients had documented progression to deep venous involvement. The most common site of deep vein involvement was progression of disease from the greater saphenous vein in the thigh into the common femoral vein (21 patients, 70%), with 18 of these extensions noted to be nonocclusive and 12 having a free-floating component. Three patients had extended above-knee saphenous vein thrombi through thigh perforators to occlude the femoral vein in the thigh, three patients had extended below-knee saphenous disease into the popliteal vein, and three patients had extended below-knee thrombi into the tibioperoneal veins with calf perforators. At the time of the follow-up examination all 30 patients were being treated without anticoagulation. CONCLUSIONS Proximal saphenous vein thrombosis should be treated with anticoagulation or at least followed by serial duplex ultrasound evaluation so that definitive therapy may be initiated, if progression is noted. More distal superficial venous thrombosis should be carefully followed clinically and repeat duplex ultrasound scans performed, if progression is noted or patient symptoms worsen.

Open vs. endovascular repair of isolated iliac artery aneurysms: A 12-year experience

OBJECTIVE To examine contemporary operative techniques and outcomes for repair of isolated iliac artery aneurysms. METHODS We retrospectively reviewed the charts of all patients who underwent repair of an isolated iliac artery aneurysm from February 1995 to June 2007. Mycotic aneurysms and patients with concurrent infrarenal abdominal aortic aneurysms greater than 3.5 cm in diameter were excluded from analysis. Patients with prior abdominal aortic aneurysm repair were not excluded. RESULTS Fifty-six patients (96% male; mean age, 72 +/- 10 years) had either open (n = 24) or endovascular (n = 32) repair with median follow-up of 36 months. Seven patients were treated for rupture, six with open repair, and one with an endograft. Average aneurysm size for patients in the open and endovascular repair cohorts was 4.5 +/- 2.4 cm and 4.0 +/- 1.1 cm, respectively (P = .35). One episode of endograft limb thrombosis at five months was treated with catheter-directed thrombolytic therapy and stent placement. Thirty-day mortality for patients undergoing elective and emergent open repair was 1/18 (6%) and 1/6 (17%), respectively. There was no 30-day mortality for the endovascular group. Median length of stay was 10.5 days in the open group and one day in the endovascular elective group (P < .01). There was no mid-term aneurysm-related mortality in either group. Primary patency rates were similar between the open and endovascular groups at five years (100% vs. 96%, P = .07). Aneurysm sac diameter decreased in 67% (21/28) of patients that underwent endovascular repair. One patient with a Type III endoleak required relining of the endograft with a second endograft at 72 months. CONCLUSION These data demonstrate that in appropriately selected patients, endovascular repair of isolated iliac artery aneurysms is a safe, effective alternative to open repair with mid-term follow-up. Endovascular repair is associated with a significantly reduced hospital length of stay and may be associated with decreased need for transfusion and mortality when compared with open repair.

Secure fixation following EVAR with the Powerlink XL System in wide aortic necks: Results of a prospective, multicenter trial

PURPOSE Endovascular stent graft repair of abdominal aortic aneurysms (AAA) with the Endologix Powerlink System (Endologix, Inc, Irvine, Calif) has been shown to be a safe and effective alternative to open surgery in patients having an aortic neck diameter of up to 26 mm. We assessed the safety and effectiveness of AAA repair in patients with wide aortic necks (up to 32 mm in diameter) using the Powerlink XL System. METHODS Between September 2005 and June 2008, a prospective, multicenter, pivotal US Food and Drug Administration trial of the Powerlink XL System for endovascular aneurysm repair was conducted at 13 centers. Using a sizing algorithm based on computed tomography scan (CT)-based measurements, a total of 78 patients (N = 60 [pivotal trial]; N = 18 [continued access]) presenting with AAA and an infrarenal aortic neck up to 32 mm in diameter received a bifurcated stent graft via anatomical fixation at the aortoiliac bifurcation and proximal sealing with a Powerlink XL infrarenal proximal extension stent graft. Postoperatively, results were assessed with contrast-enhanced CT scans and abdominal x-rays at one, six, and 12 months, with continued annual follow-up to five years. RESULTS Predominantly male (91%), patients presented at a mean age of 73 +/- 8.6 years with mean maximum aortic neck and AAA diameters of 31 +/- 1.9 mm (range, 25 to 32 mm) and 5.7 +/- 1.0 cm (range, 4.3 to 10 cm), respectively. Challenging infrarenal aortic neck anatomy, defined as the presence of severe thrombus and/or reverse taper, was present in 85% of patients. Technical success was achieved in 98.7% of patients, with one patient requiring femoral-femoral bypass intraoperatively. Aneurysm exclusion was achieved in 100% of patients over a mean procedure time of 129 +/- 66 minutes. Patients were discharged at a mean of 2.2 days postoperatively. At the one-month CT scan, the independent core lab identified a Type II endoleak in 13 patients, distal Type I and Type II endoleak in one patient, and unknown endoleak in three patients. At 30 days, there were no deaths, conversions, ruptures, or migrations. Through one year follow-up, Type II endoleak predominated (9/10 patients with endoleak), with one proximal Type I and no Type III, IV, or unknown endoleak; no conversions, ruptures, or migrations have been observed. The one-year all-cause mortality rate was 6.4%, with 100% freedom from aneurysm-related mortality. Secondary procedures were performed within one year in five patients (6.4%) for treatment of proximal Type I endoleak (n = 2), proximal Type I/Type II endoleak (n = 1), and distal Type I endoleak (n = 2). Reduced or stable aneurysm sac diameter at one year is observed in 96% of patients. CONCLUSIONS The combination of an anatomically-fixed Powerlink bifurcated stent graft and a Powerlink XL infrarenal proximal extension appears safe and effectively excludes aneurysms in patients with wide aortic necks. These results suggest that fixation at the aortic bifurcation can provide secure fixation for patients with large diameter diseased proximal aortic necks.

Cell washing versus immediate reinfusion of intraoperatively shed blood during abdominal aortic aneurysm repair

Significant hematologic changes are known to occur following intraoperative autotransfusion of shed blood, but the clinical importance of cell washing prior to reinfusion has not been substantiated. To evaluate these changes and their relationship to the use of blood bank products and postoperative morbidity, 26 patients undergoing elective abdominal aortic aneurysm repair were prospectively randomized to reinfusion with washed shed blood or to the use of a collection system in which filtered, but unwashed, whole blood was reinfused intraoperatively. Each patient was evaluated with respect to standard metabolic and hematologic laboratory parameters preoperatively, immediately postoperatively, and 12 to 18 hours postoperatively. Patient demographic data were similar for both groups. Perioperative survival was 100% for both groups. Total blood loss and blood volume autotransfused were significantly greater in the unwashed cell group compared with the washed cell group (p = 0.00014 and p = 0.00011, respectively). Hemoglobin, fibrinogen, prothrombin time, and partial thromboplastin time levels were not significantly different between the two groups at any time perioperatively; fibrin split product and d-dimer levels were significantly higher in the unwashed cell group postoperatively (p = 0.016 and p < 0.001, respectively). Serum free hemoglobin levels were significantly higher in the immediate postoperative period in the unwashed cell group compared with the washed cell group (p = 0.0013); by 12 to 18 hours postoperatively, this difference was not significant. Haptoglobin levels were significantly lower in the unwashed cell group at both postoperative times (123 +/- 86 mg/dL versus 41 +/- 50 mg/dL, p = 0.0086; 102 +/- 66 mg/dL versus 24 +/- 36 mg/dL, p = 0.0001); however, there was no perioperative renal failure in either group. Furthermore, homologous blood product use was not significantly different between the two groups, with an average of 1.5 +/- 2.5 units of packed red blood cells given to patients in the unwashed cell group versus 0.8 +/- 1.7 units in the washed cell group (p = 0.419). Overall complications were higher and critical care and total hospital stays were longer in the unwashed cell group but did not result from autotransfusion of unwashed blood. We conclude that the intraoperative reinfusion of unwashed shed blood is safe and effective, causing transient hematologic abnormalities that normalize in the early postoperative period, and is not associated with increased mortality, or hematologic, cardiopulmonary, or renal complications.

Septic deep vein thrombosis

Anticoagulation is the cornerstone in the treatment of deep vein thrombosis. However, the treatment of septic deep vein thrombosis is controversial. Unlike septic superficial vein thrombosis, venous excision is often associated with limb-threatening or even life-threatening complications. Some authors have suggested thrombectomy as the only means of resolving the sepsis. We reviewed our experience with seven patients who had septic deep vein thrombosis. Phlebography or noninvasive studies documented deep vein thrombosis and blood cultures were positive in all patients. The mean age was 31.5 years with a male/female ratio of 5:2. All patients were treated with anticoagulants and intravenous antibiotics. One patient required surgical exploration for associated abscess of the groin. The patients became afebrile with normal white blood cell counts from 3 to 18 days after therapy was begun. No cases of recurrent sepsis occurred. We conclude that antibiotic therapy and anticoagulation are adequate treatment and therefore consider venous thrombectomy unnecessary.

Hemodynamic effects of primary closure versus patch angioplasty of the carotid artery.

This study evaluated the hemodynamic changes associated with patch angioplasty compared to primary closure of the canine carotid artery. A standard arteriotomy was closed either primarily, with a 5×28 mm expanded polytetrafluoroethylene (ePTFE) patch, or with a 10×28 mm ePTFE patch. Measurements for the primary closure group showed a systolic pressure gradient of 17 mmHg across the closure and a peak systolic velocity increase of 58% at mid-closure compared to proximal inflows. Flow turbulence increased at mid-closure in the 10 mm patch group, with the percent spectral window lowered from 0.50 to 0.36. These data show that primary vessel closure creates a mild local stenosis with flow acceleration but no flow turbulence. No significant hemodynamic disturbances are caused by a moderate sized patch; however, a large patch relative to native vessel dimensions creates marked flow disturbances throughout the cardiac cycle. As turbulence and flow separation are felt to contribute to restenosis, care should be taken in the selection of patch size when used following carotid endarterectomy.

Diagnosis of total internal carotid occlusions with duplex ultrasound and ultrasound contrast

It remains a significant technical challenge for duplex ultrasound to accurately differentiate between total and near total internal carotid artery (ICA) occlusions. We have evaluated the efficacy of an ultrasound contrast agent combined with improved imaging techniques in patients with suspected carotid artery occlusions. Patients identified by conventional duplex ultrasound between January and August 2003 as having a possible ICA occlusion were eligible for study. A 1 mL bolus of ultrasound contrast agent was injected into a 50 mL bag of normal saline and given intravenously at a rate of approximately 4–5 mL/minute. Ultrasound imaging and spectral Doppler analysis were done using tissue harmonic imaging for optimum contrast agent to soft tissue discrimination, or with the direct B-mode imaging of blood flow to maximize the brightness of the circulating contrast agent. Ten patients were identified, 6 men and four women with a mean age of 68.3 years. Nine suspected total ICA occlusions were unilateral and 1 was bilateral. Imaging with contrast agent confirmed occlusion of the ICA in 7 of 10 patients; 3 patients had near-total occlusion with flow detected in the distal ICA by spectral and color Doppler. All 3 of these near-total occlusions were ultimately confirmed by either conventional or magnetic resonance carotid angiography. The contrast agent was most beneficial in improving the detection of minimal flow beyond a severe stenosis and in evaluating flow dynamics in the presence of severely calcified plaque. We conclude that the use of an ultrasound contrast agent with newer duplex ultrasound imaging techniques can reliably distinguish total from near-total internal carotid artery occlusions. Future prospective studies should be able to define the efficacy of ultrasound contrast agents in improving the overall diagnostic accuracy of duplex ultrasound in technically difficult cases and in patients with complex peripheral vascular disease.

Three-dimensional vascular imaging using Doppler ultrasound

BACKGROUND We have evaluated the efficacy of using three-dimensional reconstruction of amplitude Doppler imaging data to quantitatively assess carotid artery bifurcation stenoses. METHODS Sixty-four consecutive frames of amplitude (power) Doppler images are stored to be reassembled into a three-dimensional image representing the patent lumen. These images can then be rotated by any angle necessary to clearly view the vascular anatomy and to make quantitative ultrasound caliper measurements of the stenotic lumen and normal vessel caliber. RESULTS Three-dimensional Doppler images accurately classified 53 of 61 vessels (87%) into categories of stenosis compared with angiography. All stenoses with >60% diameter reduction were detected and classified as such, for a sensitivity of 100%. CONCLUSIONS Three-dimensional vascular imaging based on amplitude (power) Doppler data provides an accurate noninvasive technique for quantitative diagnosis of carotid bifurcation atherosclerotic disease, with selectable viewing projections that eliminate vessel overlap and other artifacts, and complements the hemodynamic data already available with two-dimensional duplex ultrasound.

Serial duplex ultrasound examinations for deep vein thrombosis in patients with suspected pulmonary embolism

PURPOSE We have prospectively evaluated the need for serial venous duplex ultrasound examinations in an inpatient population with an initially normal study result. METHODS Patients were selected for study on the basis of clinical suspicion of pulmonary embolism and possible lower extremity deep vein thrombosis, a comorbid condition contributing to a nondiagnostic ventilation/perfusion lung scan, and an initially normal bilateral venous duplex ultrasound examination that included complete evaluation of the femoropopliteal system and the deep calf veins. Repeat duplex examinations were done during the same hospital admission between 5 and 14 days after the initial study. RESULTS Ninety-four patients with an initially normal duplex ultrasound examination result had repeat studies done at an average of 7.9 +/- 2.6 days. Ninety-two examination results remained normal bilaterally. Two patients had isolated intramuscular calf vein deep vein thrombosis: one in the gastrocnemius system of both calves with associated calf tenderness at 11-day follow-up and one in a mid-calf soleal vein without associated symptoms at 10 days. No patients had any evidence of deep vein thrombosis in the femoropopliteal or tibioperoneal venous systems. CONCLUSIONS Serial follow-up duplex ultrasound evaluation is unnecessary after an initially complete, normal study in patients with symptoms who have suspected pulmonary embolism and nondiagnostic ventilation-perfusion lung scans.