Behçet's disease: endovascular management of a ruptured peripheral arterial aneurysm.

Traditionally, bypass grafts are at a high risk for thrombosis or anastomotic degeneration in patients with Behçet's disease. We report the successful deployment of a vein-covered stent across the neck of a ruptured peripheral arterial aneurysm, via a remote site access, with intermediate-term follow-up. Covered stents may represent an attractive alternative to open surgical bypass for the management of aneurysms in patients with Behçet's disease.

Mechanical thrombectomy as a first-line treatment for arterial occlusion.

The use of percutaneous mechanical thrombectomy devices to restore flow to an acutely ischemic limb is gaining popularity. Potential benefits include the minimally invasive nature of the procedure, rapid blood flow restoration, and a decrease in the dose and duration of adjunctive pharmacologic thrombolytic agents when required. A detailed description of the currently available mechanical thrombectomy devices, preclinical device evaluation, and published clinical trials for the management of acute limb-threatening ischemia are provided.

Cholesterol granulomas of the lungs associated with microangiopathic hemolytic anemia and thrombocytopenia in pulmonary hypertension.

Cholesterol granulomas unrelated to endogenous lipoid pneumonia, pulmonary alveolar proteinosis, or cholesterol pneumonia are a rare finding during pneumectomy or autopsy. They have been occasionally reported in association with pulmonary hypertension. We report a case where these lesions were associated with long-standing pulmonary hypertension and microangiopathic hemolytic anemia and thrombocytopenia. Plexiform lesions were present in the pulmonary vasculature secondary to pulmonary hypertension, causing hemolysis and thrombocytopenia. We suggest that destruction of red blood cells and platelets could provide membrane lipids that are taken up by phagocytic cells, which promotes the formation of these cholesterol deposits.

Infection in the ischemic lower extremity.

Infections in the lower extremity of the patient with ischemia can cover a broad spectrum of different diseases. An understanding of the particular pathophysiologic circumstances in the ischemic extremity can be of great value in understanding the natural history of the disease and the potential complications that may occur. Optimizing blood flow to the extremity by using revascularization techniques is important for any patient with an ischemic lower extremity complicated by infection or ulceration. Infections in the ischemic lower extremity require local débridement and systemic antibiotics. For severe infections, such as necrotizing fasciitis or the fetid foot, more extensive local débridement and even amputation may be required. Fundamentals of managing prosthetic graft infection require removing the infected prosthesis, local wound débridement, and systemic antibiotics while attempting to preserve viability of the lower extremity using autogenous graft reconstruction.

The histologic characteristics of primary and restenotic carotid plaque.

BACKGROUND: Although smooth muscle cell proliferation is a prominent feature of restenosis in experimental models, the role of cellular proliferation in the initiation and progression of carotid restenosis is not well documented. METHODS: Between 1985 and 1995, 35 carotid endarterectomies (CEA) in 34 patients were performed for restenosis. Patient risk factors, cerebrovascular symptoms, and operative findings were recorded. Tissue specimens from 29 of these cases and 14 original specimens from the same patient were examined by light microscopy (H&E, trichrome, elastochrome, and Alcian blue) and immunohistochemistry (alpha actin, CD 68, vWF, and proliferating nuclear cell antigen (PCNA)) in order to determine the morphologic characteristics and cellular proliferative activity of the plaque. RESULTS: Hemodynamically significant recurrent stenosis occurred in the 29 patients (69% symptomatic) between 2 months and 30 years after their initial CEAs. Eleven of 29 (38%) lesions were removed early (< 3 years). Recurrent lesions were characterized based on their components as neointimal thickening, 24% (7/29), neointimal thickening and atherosclerosis, 55% (16/29), or atherosclerotic, 21% (6/29). Nineteen of 29 (66%) plaques were complicated by mural thrombus or intraplaque hemorrhage. An inflammatory cell infiltrate consisting of macrophages and T lymphocytes was observed adjacent to areas of recurrent atherosclerosis and macrophages in regions of intimal thickening. Although infrequently present (generally 1-3% of cells) PCNA-positive cells were detected in 41% (12 of 29) of recurrent and 14% (2 of 14) of primary plaques. No PCNA-positive cells were detected in the remaining 67% (29 of 43) of specimens. There was no statistical difference in the number of PCNA-positive cells in early recurrent lesions compared to those recurring after 3 years (36% vs 44%). PCNA immunoreactivity when present was most commonly noted in macrophages associated with thrombus or atheroma rather than smooth muscle cells. CONCLUSIONS: Although evidence of cellular proliferation was observed in 40% of recurrent carotid endarterectomy lesions, the proliferation rate was low (1-3%) and unrelated to the time interval of recurrence. Proliferative activity was most pronounced in macrophages associated with intraplaque hemorrhage or atheroma. The contribution of inflammatory cells to the biologic behavior of restenotic lesions requires further investigation.

Distal revascularization-interval ligation for limb salvage and maintenance of dialysis access in ischemic steal syndrome.

PURPOSE: Traditional options for treating ischemic steal syndrome related to a functioning dialysis access graft or fistula include banding or ligation. Unfortunately, these techniques usually result in inconsistent limb salvage, loss of a functional access, or both. We report our experience with an alternative method of limb revascularization that eliminates steal while maintaining continuous dialysis access. METHODS: Patients who had critical limb ischemia and functioning arteriovenous fistulae (AVF) underwent color-flow duplex scanning, digital photoplethysmography, and arteriography. Arterial ligation distal to the AVF origin eliminated the steal physiologic mechanism while arterial bypass grafting from above to below the AVF revascularized the extremity (distal revascularization-interval ligation [DRIL] procedure). RESULTS: From March 1994 through December 1996, 21 patients with functioning extremity AVFs presented with critical ischemia and steal syndrome. Eleven patients had chronic ischemia with rest pain, paresthesias, or ulcerations related to nine native fistulae (six brachiocephalic, two basilic vein transpositions, one radiocephalic) and two prosthetic bridge grafts (one upper arm, one lower extremity). Acute ischemia developed in 10 patients related to three native fistulae (two brachiocephalic, one radiocephalic) and seven prosthetic bridge grafts (three forearm, three lower extremity, one upper arm). All 21 patients were treated with the DRIL technique. Three of these patients required treatment for ischemia at the time of AVF construction. Nineteen of 21 bypass procedures were performed with autogenous vein, including nine brachial-brachial, three brachial-radial, two radial-radial, two brachial-ulnar, one popliteal-popliteal, one femoral-popliteal, and one femoral-peroneal. Polytetrafluoroethylene grafts were used for one external iliac-popliteal bypass graft and one axillary-brachial bypass graft. Limb salvage and maintenance of a functional fistula were achieved in 100% and 94%, respectively, at 18 months by life-table analysis. CONCLUSION: The DRIL technique reliably restores antegrade flow to the ischemic limb, eliminates the potential pathway for the steal physiologic mechanism, and maintains continuous dialysis access in these difficult patients.

Immunocytochemical determination of cell type and proliferation rate in human vein graft stenoses.

PURPOSE: Vascular reconstructions are prone to fail as a result of the development of stenotic lesions, which have historically been attributed to myointimal hyperplasia. In animal models, these lesions are associated with marked proliferative smooth muscle cell (SMC) response to vascular injury. However, recent studies using sensitive immunocytochemical techniques in human lesions have generally failed to detect significant cellular proliferation. To clarify the role of cellular proliferation in humans, we characterized the cellular composition and proliferative index of 14 early infrainguinal vein graft stenoses. METHODS: All infrainguinal vein grafts at our institution are prospectively enrolled in a duplex surveillance protocol, the details of which have been previously reported. Among 98 grafts placed within the last year, 11 patients were identified with 14 progressive, focal, high-grade lesions that met previously established threshold criteria for prophylactic revision to prevent graft thrombosis. Lesions were first detected from 1 week to 7 months after surgery and were removed and replaced with segmental interposition grafts (1.5 to 10 months). Freshly excised lesions were placed in Methyl Carnoy's fixative, paraffin embedded, and serially sectioned. The cellular composition of each lesion was determined with cell-specific immunochemical reagents: alpha SMC actin, von Willebrand factor (endothelial cell), CD 68 (macrophage), and CD 45RB (monocyte). Actively proliferating cells were identified using antibody to proliferating cell nuclear antigen (PCNA). The identity of PCNA-positive cells was determined by double-label immunocytochemical staining, and the proliferative index (PCNA-positive cells/total cells x 100) was calculated by computer-assisted counts of representative gridded cross-sections of each lesion. RESULTS: All excised lesions demonstrated marked thickening with severe luminal encroachment and were highly cellular, with a predominance of alpha SMC actin+. Endothelial cells on the blood flow surface were present to a variable degree, and seven lesions exhibited striking numbers of macrophages and monocytes. The latter cell types were most abundant near microvessels in the deep neointima and adventitia. Active cellular proliferation was identified primarily in SMCs, with a mean PCNA index of 1.34%. However, significant PCNA reactivity was not limited to SMCs, but was also identified in macrophages and monocytes, particularly in lesions greater than 3 months old. CONCLUSIONS: Previous immunocytochemical studies of human coronary restenosis atherectomy specimens have generally detected low rates of cellular proliferation (0.5%), but these lesions may not truly represent myointimal hyperplasia, rather a mixture of atherosclerosis, thrombosis, and "restenosis." In contrast, the present study of early human vein graft lesions detected by duplex surveillance indicates that significant cellular proliferation occurs, although rates are lower than those obtained in animals such as the rat carotid injury model. In addition, although SMCs are the predominant proliferating cell type in human vein grafts, our identification of proliferating monocytes and macrophages raises the question of the contribution of an inflammatory component to the development of human lesions. The present study represents the first report of PCNA determination in a series of human infrainguinal vein grafting procedures.

Prospective validation of threshold criteria for intervention in infrainguinal vein grafts undergoing duplex surveillance.

Although color flow duplex surveillance (CFDS) of infrainguinal vein grafts has gained wide acceptance, definitive criteria mandating graft revision remain to be established. We prospectively evaluated 101 infrainguinal vein grafts undergoing CFDS in order to validate threshold duplex criteria for intervention which were derived from our previous experience and that reported by others. Complete CFDS of the bypass conduit and adjacent inflow and outflow arteries and Doppler-derived ankle brachial indices (ABI) were obtained every 3 months x 4 and every 6 months thereafter. The following threshold criteria mandating further evaluation and intervention to prevent graft occlusion were applied: high-velocity criteria (HVC) defined as peak systolic velocity (PSV) > 300 cm/sec and velocity ratio (Vr) > 3.5; low-velocity criteria (LVC) defined as PSV < 45 cm/sec; an ABI decrease > 0.15. Fifty-one grafts had normal serial CFDS and ABI; none subsequently occluded or required revision. Stenosis was detected by CFDS in 43 grafts (PSV > 180 cm/sec, Vr > 1.5). Within this subgroup, 54% of grafts subsequently required revision (20/43) or occluded (3/43). All grafts in this subgroup with stenoses progressed to PSV > 300 or Vr > 3.5 prior to revision or occlusion. Ten lesions (23%) regressed spontaneously without intervention (mean PSV 252 cm/sec, mean Vr 3.2); 10 lesions (23%) are stable, non-progressive, and remain under surveillance. Two grafts were abnormal by LVC; one was successfully revised, the other occluded prior to intervention. Five grafts had normal CFDS and ABI decrease > 0.15. Four were revised (three inflow lesions, one outflow lesion) and one occluded (missed lesion by CFDS). Only five graft occlusions occurred in the entire series: three grafts met HVC and occluded prior to intervention; one developed an ABI drop of 0.4 due to graft stenosis missed by CFDS and uncovered following thrombolysis, and the other graft met LVC and occluded prior to intervention. Infrainguinal vein grafts with normal serial CFDS and ABI are at minimal risk of spontaneous graft occlusion. When CFDS is abnormal (PSV > 180 cm/sec, Vr > 1.5), over 50% of grafts will ultimately require revision or progress to occlusion. Grafts with such lesions can be safely monitored by CFDS until progression to lesions meeting HVC occurs with minimal risk of graft occlusion. A decrease in ABI > 0.15 with normal CFDS mandates arteriography to identify inflow and outflow lesions or a missed graft stenosis. The present study prospectively validates threshold intervention criteria for graft lesions meeting HVC (PSV > 300 cm/sec, Vr > 3.5), LVC (PSV < 45 cm/sec throughout graft) or an ABI decrease > 0.15.

The relative contributions of carotid duplex scanning, magnetic resonance angiography, and cerebral arteriography to clinical decisionmaking: a prospective study in patients with carotid occlusive disease.

PURPOSE: Recent reports suggest that 80% to 90% of patients can safely undergo carotid endarterectomy on the basis of duplex scanning alone without cerebral angiography. Other investigators have recommended that a complementary imaging study such as magnetic resonance angiography (MRA) also be obtained. METHODS: We prospectively evaluated 103 consecutive patients with carotid occlusive disease. Eighty percent of patients were symptomatic. All 103 patients underwent duplex scanning and arteriography. Additional noninvasive tests included computed tomography, magnetic resonance imaging, and MRA in 50%, 56%, and 48% of patients, respectively. At a multispecialty conference all studies except angiograms were reviewed, and a treatment decision was made by a panel of attending vascular surgeons, neurosurgeons, and neurologists. The cerebral angiograms then were reviewed and changes made to final treatment plans were noted. RESULTS: After review of noninvasive studies, 30 of 103 of patients (29%) were believed to require arteriography because of diagnostic uncertainty of carotid occlusion in three patients, suggestion of nonatherosclerotic disease in four, suggestion of proximal disease in two, suboptimal noninvasive studies in one, and uncertainty of therapy despite good-quality noninvasive studies in 20 patients primarily with borderline stenoses and unclear symptoms. In 10 of these 30 patients (33%) management decisions were changed on the basis of angiogram results. Of the remaining 73 patients (71%) in whom the panel felt comfortable proceeding with operative or medical therapy without angiography, only one patient (1.4%) would have had management altered by results of angiography. MRA results concurred with duplex findings in 92% of studies, but did not alter management in any patient. CONCLUSIONS: In patients with good-quality duplex images, focal atherosclerotic bifurcation disease, and clear clinical presentation, treatment decisions can be made without arteriography. In 30% of patients angiography is useful in clarifying decisionmaking. MRA is unlikely to influence management decisions and is thus rarely indicated.