Role of intravascular ultrasound imaging during endovascular interventions of failing hemodialysis access grafts.

BACKGROUND: Arteriovenous (AV) access graft complications represent a serious complication in patients undergoing hemodialysis. Angiography is one method of visualizing them. However, angiography is not always an effective means of detecting lesions that occur in this context. Intravascular ultrasound (IVUS) is an adjunct modality used to identify stenoses responsible for failing access by identifying multiple stenoses, including those that are most severe. The purpose of this study was to define the value of IVUS in patients with failing AV access grafts by comparing digital subtraction angiography (DSA) alone with DSA followed by IVUS. METHODS: This was a single-center randomized study comparing IVUS with DSA in patients with failing hemodialysis access grafts. It consisted of 100 randomized hemodialysis patients presenting with failing AV access who were being considered for endovascular intervention. Interventions in the control group were guided by DSA alone, whereas interventions in the test group were guided by DSA followed by IVUS. Patients were observed for 6 months after intervention. The primary end point was the time in days to AV access graft failure after the index intervention, expressed as median and interquartile range. Secondary analyses included influence of DSA and IVUS on index procedure decision-making and percentage of patients with AV access graft reinterventions or discontinuation through 3 and 6 months. RESULTS: Median time to first AV graft reintervention or discontinuation was 61 days in the test group and 30 days in the control group (P = .16), with analysis limited to patients who experienced reintervention or discontinuation (n = 59). IVUS resulted in a change in treatment plan in 76% (44/58) of patients, with no treatment change after IVUS in 24% (14/58) of patients. At 6 months, approximately 35% of patients in both the control and test groups remained free from reinterventions (P = .88). At 6 months, approximately 75% of patients in the control group and 80% of patients in the test group remained free from AV graft discontinuation or abandonment (P = .45). CONCLUSIONS: This pilot study suggests that addition of IVUS to standard angiography during endovascular interventions of failing hemodialysis access grafts holds potential to extend the time to the first reintervention. The data support the design and execution of an adequately powered randomized trial with longer follow-up to reliably discern the clinical benefit of IVUS as an addition to standard angiography in the setting of failing AV access grafts.

A rare presentation of ruptured abdominal aortic aneurysm leading to aortoduodenal syndrome.

Duodenal obstruction is a rare complication of abdominal aortic aneurysm. Obstruction developing acutely from ruptured abdominal aortic aneurysm (RAAA) is exceedingly rare. We present a case of gastroduodenal outlet obstruction developing as the primary presentation for RAAA and a discussion of the relevant literature pertaining to the gastrointestinal complications related to the presence of intact and RAAA. Relief of obstruction is focused on direct aortic replacement with further evaluation of the upper gastrointestinal tract if indicated based on intraoperative findings.

Single-stage reconstruction of perforated choledochal cyst: case report and review of the literature.

Choledochal cysts represent a rare disease in the Western world. We reviewed our recent experience with a case of perforated choledochal cyst, define the currently accepted treatment options, and review the literature of this unusual disease. An 11-month-old girl presented with abdominal pain and distention as well as non-bilious vomiting. Subsequent workup included endoscopic retrograde cholangiopancreatography revealing a perforated type I choledochal cyst. She underwent single-stage excision and reconstruction with a Roux-en-Y hepaticojejunostomy. Perforated choledochal cyst is a rare event, and prompt surgical intervention is warranted. Single-stage cystectomy and Roux-en-Y reconstruction is possible in select patients. A thorough understanding of the pathophysiology, management, and follow-up is required.

Management of subclavian and axillary artery injuries: spanning the range of current therapy.

Injuries of the subclavian and proximal axillary arteries are potentially devastating but account for a minority of vascular injuries presenting to trauma centers in the United States. We have reviewed our recent experience with management of subclavian and axillary artery injuries in a state-designated level 1 academic trauma center and report four cases that illustrate the typical arterial injury patterns and the entire therapeutic armamentarium in its current iteration. Subclavian and proximal axillary artery injuries present as interesting surgical problems. A high index of suspicion for vascular injuries should be maintained given the mechanism and proximity to major vasculature. Consideration should always be given to the least invasive treatment options in stable patients. Awareness of multiple therapeutic modalities and indications for each should be an integral part of every surgeon's armamentarium. As with all vascular intervention, eventual failure is the rule rather than the exception; therefore, plans for longitudinal surveillance should be made independent of the technique used to treat the injury.

Native matrix metalloproteinase characteristics may influence early stenosis of venous versus arterial coronary artery bypass grafting conduits.

PURPOSE: Stenosis and occlusion rates of internal mammary artery (IMA) and saphenous vein (SV) coronary artery bypass grafts (CABGs) are markedly different, which result from respective disparities in vascular remodeling. Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) regulate vascular structure and may have important influence on graft patency. However, the MMP milieu and expression profile of the IMA and SV have not been contrasted. Therefore, the aim of this study was to assess and compare the native MMP systems in IMA vs SV conduits. METHODS: IMA (n = 10) and SV (n = 10) specimens were obtained from patients undergoing CABG surgery. Protein levels of MMP-1, MMP-2, and MMP-9, TIMP-1, a membrane-bound MMP activator (MT1-MMP), and an extracellular MMP inducer protein (EMMPRIN) were determined by immunoblotting and quantified by densitometric analysis. MMP-2 and MMP-9 activity was determined by gelatin zymography. RESULTS: MMP-2 levels were significantly higher in SV (2,218 +/- 351 pixels) vs IMA (1,012 +/- 213 pixels) specimens (mean +/- SEM]). There were no significant differences in MMP-1, MMP-9, or TIMP-1 content; however, MT1-MMP and EMMPRIN levels were significantly lower in SV (847 +/- 190 pixels, 1,742 +/- 461 pixels) vs IMA conduits (2,590 + 403 pixels, 5,606 + 678 pixels), respectively (p < 0.05). MMP-9 activity was similar while MMP-2 activity was significantly increased in SV vs IMA specimens. CONCLUSIONS: SV and IMA conduits harbor the same MMP molecular constituents. However, MMP-2 levels and activity are significantly more abundant in the SV compared to the IMA. These differences may contribute to the early pathologic remodeling of the SV vs IMA conduit following CABG surgery.

Decreased vascular matrix metalloproteinase abundance in diabetic patients with symptomatic macroangiopathy.

The incidence of diabetic amputations is 2- to 3-fold higher in African-American patients compared to Caucasians. Vascular remodeling characterized by extracellular matrix (ECM) deposition occurs in diabetes and contributes to vascular complications. The matrix metalloproteinases (MMP) play important roles in the regulation of collagen turnover and vascular remodeling. However, the temporal expression profile of MMPs in diabetic vascular tissue during the disease process remained unknown. The objective of this study was to compare the vascular MMP system in African-American diabetic patients without symptoms to patients undergoing lower limb amputation due to severe vascular complications. Internal mammary artery (IMA, N = 8) and anterior/posterior tibial artery (AT/PT, N = 8) specimens were obtained from patients undergoing coronary artery bypass grafting and lower limb amputation, respectively. ECM inducer protein (EMMPRIN) and MMP activator membrane-type MMP (MT1-MMP), as well as MMP-1, -2, and -9, were quantified by immunoblotting and densitometry (pixels). MMP-1 and -9 levels were decreased from 398 +/- 61 and 175 +/- 54 pixels, respectively, in IMA tissue to 287 +/- 31 and 51 +/- 36 pixels in the AT/PT tissue (P < .05). Both EMMPRIN and MT1-MMP expression was increased by 3-fold in AT/PT preparations (P < .05). These results provided evidence that the molecular components required for the induction and activation of the MMP system exist in arterial vasculature and, MMP expression is downregulated in diabetic patients with severe complications despite elevated MMP inducer and activator proteins. Decreased MMP activity may contribute to pathological remodeling leading to increased incidence of amputations in African-American patients.