Vacuum-pack temporary abdominal wound management with delayed-closure for the management of ruptured abdominal aortic aneurysm and other abdominal vascular catastrophes: absence of graft infection in long-term survivors.

Patients who undergo open repair of ruptured abdominal aortic aneurysms (rAAA) may require delayed abdominal wound closure to prevent the adverse consequences of intra-abdominal hypertension and abdominal compartment syndrome. However, surgeons may be reticent to use delayed abdominal closure techniques due to concern that such management may increase the risk of graft infection. We retrospectively reviewed our patient experience with rAAA and other vascular catastrophes in which vacuum-pack abdominal wound management with delayed closure was used between 2000 and 2007. Eighteen of 23 patients treated with delayed closure survived (78%). In five early deaths, graft infection was not clinically suspected. Sixteen of 20 rAAA patients survived, with abdominal wound closure achieved at a mean of 4 days. Mean follow up was 53 months, the longest among comparable series. Graft infection has not been encountered in this group. Our results suggest that the potential risk of graft infection should not outweigh the benefits of vacuum-pack temporary abdominal wound management with delayed closure in critically ill patients at high risk for intra-abdominal hypertension and abdominal compartment syndrome after major abdominal vascular procedures.

Carotid artery stenting for stenosis following cervical radiotherapy: report of early failure with associated stent fracture.

Experience with carotid artery stenting (CAS) as an alternative to carotid endarterectomy (CE) for management of carotid stenosis continues to evolve. We report the case of a 64-year-old man who was treated with bilateral CAS for stenoses, which developed 7 years following thyroidectomy, neck dissection, and radiotherapy. Although long considered an ideal alternative to CE in this clinical setting, CAS in this case was complicated by multiple episodes of recurrent stenosis in his left carotid, managed by balloon angioplasty. Severe, early recurrence in his right carotid associated with a type III stent fracture was managed by CE. Close surveillance and intervention prevented neurologic morbidity. This case, combined with emerging published experience, argues for reappraisal of the general consensus that CAS is an ideal alternative to CE for radiotherapy-associated carotid stenoses.

Matrix metalloproteinases in medial arterial calcification: potential mechanisms and actions.

Arterial calcification is now understood to be an actively regulated process with promoters and inhibitors similar to those seen remodeling bone. It occurs in two distinct forms involving either the atherosclerotic intimal or the media. The amount of calcification found in the tibial arteries of the lower extremity is a better predictor of amputation than atherosclerosis risk factors and the ankle brachial index. We and others have recently demonstrated that matrix metalloproteinases (MMPs) play a critical role in the development of experimental arterial calcification in rodent models. The mechanisms by which MMPs may regulate arterial calcification, however, are not completely understood. While MMPs have traditionally been thought to function primarily in the degradation of extracellular matrix molecules, recent data suggest that MMPs may also function as important regulators of matrix biology, inflammation, and osteogenesis. In this review, we will examine recent data on the potential mechanisms by which MMPs may function in the control of arterial calcification.

Metalloproteinase expression in venous aneurysms.

INTRODUCTION: Although recognized with increasing frequency, the pathogenesis of venous aneurysms (VA) remains poorly understood. We evaluated 8 patients with 10 VA for the presence, localization and activity of metalloproteinases (MMPs). METHODS: Tissue specimens from VA (n=8), normal saphenous vein (NSV n=7) and varicose veins (VV n=7 were compared by histology and immunohistochemistry (IHC). Histologic sections were stained with H&E, Movats pentachrome and toluidine blue, and IHC specimens with antibodies to CD68, MMP2, MMP9, and MMP13. Protein expression and enzyme activity were determined by Western immunoblotting and zymography. RESULTS: Three of 4 patients with popliteal VA presented with edema and leg pain and the remaining patient with deep venous thrombosis (DVT) and pulmonary embolism (PE). The 5 popliteal VA were treated by; excision and reanastomosis (n=2) lateral venorrhaphy (n=2) and spiral saphenous vein graft (n=1). The 3 patients with 4 upper extremity VA had discomfort over a compressible mass. Two of the VA were excised and the remaining patients aneurysm ruptured spontaneously. The mesenteric VA, an incidental finding at laparotomy was excised. Thrombus was present in 2 popliteal, 1 upper extremity and in the mesenteric aneurysm. Histologically, VA and VV were characterized by fragmentation of the elastic lamellae, loss of smooth muscle cells (SMCs) and attenuation of the venous wall when compared to NSV. Varicose veins and VA also demonstrated increased expression of MMP-2, MMP-9 and MMP-13 in endothelial cells (ECs), SMCs and adventitial microvessels compared to NSV. Both pro-MMP-2 and pro-MMP-9 were detected by zymography in VA,VV and NSV but only MMP-2 activity was demonstrable. CONCLUSIONS: The structural changes in the venous wall in addition to the increased expression of MMP-2, MMP-9 and MMP-13 in VA compared to NSV and VV suggests a possible causal role for these MMPs in their pathogenesis.

The use of covered nitinol stents to salvage dialysis grafts after multiple failures.

The increasing number of patients requiring hemodialysis and the limited number of access sites have resulted in an increase in multiple graft revisions to maintain access for hemodialysis. Venous outflow or anastomotic stenoses in vascular grafts tend to recur and contribute to the difficulty in maintaining a functioning graft. Thus, extending the life of a failed graft becomes an important objective of this study, which was to assess the use of covered nitinol stents to salvage expanded polytetrafluoroethylene (ePTFE) grafts with venous anastomotic or outflow stenosis that have failed after multiple revisions. This is a review of 8 failed non-autogenous ePTFE grafts with isolated venous anastomotic or proximal outflow stenoses that had undergone multiple previous revisions, had failed percutaneous transluminal angioplasty (PTA), and required placement of a covered nitinol stent. Graft locations were forearm (2), upper arm (4), and femoral (2). The mean number of interventions per patient before stent placement was 5.87 thrombectomies (range 2-28) and 3.38 balloon angioplasties (range 2-19). Five patients had 0.62 interposition grafting and 3 had patch angioplasty. All 8 patients (100%) underwent successful dialysis after thrombectomy and stenting. The primary and secondary patency rates after stent placement were 50% and 75%, and 25% and 75%, at 3 and 6 months, respectively. Percutaneous thrombectomy, balloon angioplasty, and concomitant covered nitinol stent placement extend the function of hemodialysis access grafts that have previously failed multiple times.