Revascularization for claudication: Changing the natural history of a benign disease!

OBJECTIVE: The benign natural history of intermittent claudication was first documented in 1960 and has been reconfirmed in several subsequent studies. Excellent outcomes in patients with intermittent claudication can be achieved with exercise therapy and optimal medical management. Professional society guidelines have clearly stated that revascularization procedures should be performed only in patients with incapacitating claudication who have failed conservative therapy. Despite these guidelines, revascularization procedures, primarily percutaneous interventions, have been increasingly utilized in patients with claudication. Many of these patients are not even offered an attempt at medical therapy, and those who are often do not undergo a full course of treatment. Many studies document significant reintervention rates following revascularization, which are associated with increased rates of acute and chronic limb ischemia that may result in significant rates of amputation. The objectives of this study were to compare outcomes of conservative therapy to those seen in patients undergoing revascularization procedures and to determine the impact of revascularization on the natural history of claudication. METHODS: Google Scholar and PubMed were searched for manuscripts on the conservative management of claudication and for those reporting outcomes following revascularization for claudication. RESULTS: Despite early improvement in claudication symptoms following revascularization, multiple studies have demonstrated that long-term outcomes following revascularization are often no better than those obtained with conservative therapy. High reintervention rates (up to 43% for tibial atherectomies) result in high rates of both acute and chronic limb ischemia as compared with those patients undergoing medical therapy. In addition, amputation rates as high as 11% on long-term follow-up are seen in patients undergoing early revascularization. These patients also have a higher incidence of adverse cardiovascular events such as myocardial infarctions compared with patients treated medically. CONCLUSIONS: Revascularization procedures negatively impact the natural history of claudication often resulting in multiple interventions, an increase in the incidence of acute and chronic limb ischemia, and an increased risk of amputation. Accordingly, informed consent requires that all patients undergoing early revascularization must be appraised of the potential negative impact of revascularization on the natural history of claudication.

Spontaneous iliac vein rupture: An uncommon, but frequently lethal, event.

Spontaneous rupture of the iliac veins is a distinctly uncommon problem often misdiagnosed as an arterial rupture because of significant retroperitoneal bleeding. It often occurs with acute left-sided deep vein thrombosis and physical activities that exacerbate acute venous hypertension. A significant number of these patients will have anatomy associated with May-Thurner syndrome. Delayed imaging on computed tomography scanning might suggest a venous etiology for a retroperitoneal hematoma rather than arterial bleeding. We found 53 previously reported cases of iliac vein rupture Our report details two additional cases and the treatment options and outcomes.

Long-term Results With CorMatrix Extracellular Matrix Patches After Carotid Endarterectomy.

BACKGROUND: Previous reports of extracellular matrix (ECM) patch use after carotid endarterectomy (CEA) have noted an approximately 10% rate of pseudoaneurysm (PSA) formation. PSA-related rupture of ECM patches has also been described after femoral artery repair. In these studies, different thicknesses (4-ply versus 6-ply) and no standard length of soaking the patch in saline before implantation were used. Herein, we describe our experience with ECM CorMatrix patches in 291 CEAs with 6-ply patches. METHODS: The records of 275 consecutive patients undergoing 291 CEAs with CorMatrix 6-ply patches beginning in November of 2011 and extending until 2015 were reviewed. Only 6-ply patches and a 1 min hydration time in saline were used in all patients. No shunts were used. RESULTS: There were three deaths within the first 30 d secondary to subsequent cardiac surgical procedures. Nine patients experienced a perioperative stroke (3.1%), only one of which occurred secondary to an occluded internal carotid artery. One patient had a transient ischemic attack with a patent endarterectomy site. In follow-up, 11 patients (4.5%) developed severe recurrent stenoses requiring reintervention. Only one patient (0.34%) developed a PSA at 2 years possibly secondary to chronic infection. The median follow-up was 72 mo. CONCLUSIONS: Our experience with 6-ply CorMatrix ECM patches and a brief period of soaking demonstrated that these patches performed well in patients requiring a CEA. Only one PSA was noted.

TSG-6 is highly expressed in human abdominal aortic aneurysms.

BACKGROUND: The formation of abdominal aortic aneurysms (AAA) is characterized by a dominance of proinflammatory forces that result in smooth muscle cell apoptosis, extracellular matrix degradation, and progressive diameter expansion. Additional defects in the antiinflammatory response may also play a role but have yet to be fully characterized. TSG-6 (TNF-stimulated gene-6) is a potent antiinflammatory protein involved in extracellular matrix stabilization and cell migration active in many pathological conditions. Here, we describe its role in AAA formation. METHODS: Blood and/or aortic tissue samples were collected from organ donors, subjects undergoing elective AAA screening, and open surgical AAA repair. Aortic specimens collected were preserved for IHC or immediately assayed after tissue homogenization. Protein concentrations in tissue and plasma were assayed by ELISA. All immune cell populations were assayed using FACS. In vitro, macrophage polarization from monocytes was performed with young, healthy donor PBMCs. RESULTS: TSG-6 was found to be abnormally elevated in both the plasma and aortic wall of patients with AAA compared with healthy and risk-factor matched non-AAA donors. We observed the highest tissue concentration of TSG-6 in the less-diseased proximal and distal shoulders compared with the central aspect of the aneurysm. IHC localized most TSG-6 to the tunica media with minor expression in the tunica adventitia of the aortic wall. Higher concentrations of both M1 and M2 macrophages where also observed, however M1/M2 ratios were unchanged from healthy controls. We observed no difference in M1/M2 ratios in the peripheral blood of risk-factor matched non-AAA and AAA patients. Interesting, TSG-6 inhibited the polarization of the antiinflammatory M2 phenotype in vitro. CONCLUSIONS: AAA formation results from an imbalance of inflammatory forces causing aortic wall infiltration of mononuclear cells leading to the vessel breakdown. In the AAA condition, we report an elevation of TSG-6 expression in both the aortic wall and the peripheral circulation.

Characterization of visual pigments, oil droplets, lens and cornea in the whooping crane Grus americana.

Vision has been investigated in many species of birds, but few studies have considered the visual systems of large birds and the particular implications of large eyes and long-life spans on visual system capabilities. To address these issues we investigated the visual system of the whooping crane Grus americana (Gruiformes, Gruidae), which is one of only two North American crane species. It is a large, long-lived bird in which UV sensitivity might be reduced by chromatic aberration and entrance of UV radiation into the eye could be detrimental to retinal tissues. To investigate the whooping crane visual system we used microspectrophotometry to determine the absorbance spectra of retinal oil droplets and to investigate whether the ocular media (i.e. the lens and cornea) absorb UV radiation. In vitro expression and reconstitution was used to determine the absorbance spectra of rod and cone visual pigments. The rod visual pigments had wavelengths of peak absorbance (λmax) at 500 nm, whereas the cone visual pigment λmax values were determined to be 404 nm (SWS1), 450 nm (SWS2), 499 nm (RH2) and 561 nm (LWS), similar to other characterized bird visual pigment absorbance values. The oil droplet cut-off wavelength (λcut) values similarly fell within ranges recorded in other avian species: 576 nm (R-type), 522 nm (Y-type), 506 nm (P-type) and 448 nm (C-type). We confirm that G. americana has a violet-sensitive visual system; however, as a consequence of the λmax of the SWS1 visual pigment (404 nm), it might also have some UV sensitivity.

The use of cryopreserved aortoiliac allograft for aortic reconstruction in the United States.

BACKGROUND: Aortic infections, even with treatment, have a high mortality and risk of recurrent infection and limb loss. Cryopreserved aortoiliac allograft (CAA) has been proposed for aortic reconstruction to improve outcomes in this high-risk population. METHODS: A multicenter study using a standardized database was performed at 14 of the 20 highest volume institutions that used CAA for aortic reconstruction in the setting of infection or those at high risk for prosthetic graft infection. RESULTS: Two hundred twenty patients (mean age, 65; male:female, 1.6/1) were treated since 2002 for culture positive aortic graft infection (60%), culture negative aortic graft infection (16%), enteric fistula/erosion (15%), infected pseudoaneurysm adjacent to the aortic graft (4%), and other (4%). Intraop cultures indicated infection in 66%. Distal anastomosis was to the femoral artery and iliac. Mean hospital length of stay was 24 days, and 30-day mortality was 9%. Complications occurred in 24% and included persistent sepsis (n = 17), CAA thrombosis (n = 9), CAA rupture (n = 8), recurrent CAA/aortic infection (n = 8), CAA pseudoaneurysm (n = 6), recurrence of aortoenteric fistula (n = 4), and compartment syndrome (n = 1). Patients with full graft excision had significantly better outcomes. Ten (5%) patients required allograft explant. Mean follow-up was 30 ± 3 months. Freedom from graft-related complications, graft explant, and limb loss was 80%, 88%, and 97%, respectively, at 5 years. Primary graft patency was 97% at 5 years, and patient survival was 75% at 1 year and 51% at 5 years. CONCLUSIONS: This largest study of CAA indicates that CAA allows aortic reconstruction in the setting of infection or those at high risk for infection with lower early and long-term morbidity and mortality than other previously reported treatment options. Repair with CAA is associated with low rates of aneurysm formation, recurrent infection, aortic blowout, and limb loss. We believe that CAA should be considered a first line treatment of aortic infections.

Long-term results with cryopreserved arterial allografts (CPAs) in the treatment of graft or primary arterial infections.

OBJECTIVE: Our purpose was to evaluate our results with CPAs in patients with infected grafts or primary arterial infection with emphasis on long-term durability of these grafts. METHODS: To evaluate the long-term durability of CPAs, clinical outcomes were analyzed following their use for either graft or primary arterial infections at a single institution over a 9-y period (2000-2009). The 30-d mortality rate, 90-d mortality rate, and the cause of early mortality were determined in each case. Among those surviving 90 d, the grafts were evaluated for subsequent failure. RESULTS: From 2000 through 2009, 51 patients with either infected prosthetic grafts (35) or primary arterial infections (15) received CPAs. One patient had infection of a previously placed thoracic allograft. Forty-three graft infections involved either the thoracic or abdominal aorta. Eleven patients presented with fulminant sepsis with systemic inflammatory response syndrome (SIRS), seven of whom died postoperatively. Eight patients presented with aorto-enteric, esophageal, or bronchial fistulae with infected prosthetic grafts. The 30-d mortality rate was 25.5% (11 deaths) seven of which occurred in patients with SIRS. The 90-d mortality rate was 41.4%. There were 10 graft failures, seven occurring in patients with aorto-enteric or bronchial fistulae all of whom had recurrent hemorrhage. The other three graft failures were due to anastomotic hemorrhage in the early postoperative period. Among those surviving 90 d, the mean follow-up was 46.4 mo (range 1-112 mo). No aneurysmal degeneration of the CPAs was noted. Only one subsequent allograft graft failure was noted among those surviving more than 90 d. CONCLUSIONS: CPAs are a suitable option in dealing with cardiovascular infections. Patients with enteric or bronchial fistulae are a difficult group to treat perhaps because of ongoing contamination of the allograft. The operative mortalities are largely determined by patient comorbidities (SIRS). Subsequent degeneration or infection of the CPAs is rare.