Isolated dissection of the abdominal aorta: clinical presentation and therapeutic options

INTRODUCTION: Arterial dissection commonly affects the thoracic aorta and is associated with high morbidity and mortality rates. Although dissection of the abdominal aorta is considered rare, liberal use of diagnostic computed tomographic scan imaging for evaluation of abdominal pain has identified this process with increasing frequency. Because the clinical features and therapeutic options of isolated abdominal aortic dissection are not well characterized, we reviewed our recent experience and provide an algorithm for treatment. PATIENTS AND RESULTS: Since 1996, we have treated 10 patients with abdominal aortic dissection. The mean age was 62 +/- 17 years, and 40% were female. Presentation included abdominal pain in seven patients and lower extremity ischemia in one patient. Dissection was asymptomatic in two of the patients. Hypertension, smoking history, remote trauma, and claudication were noted in four, three, two, and two of the patients, respectively. Three patients had abdominal tenderness, three had a pulsatile mass, and five had a benign abdominal examination. The diagnosis of dissection was made on abdominal computed tomographic scan in eight cases, on arteriogram in one case, and at operation in one case. No patient had an associated thoracic aortic dissection. The dissection flap originated below or at the renal arteries in nine of the cases and at the superior mesenteric artery in one case. Length of the dissection ranged between 21 and 110 mm, and in three patients, the dissection flap extended beyond the aortic bifurcation into the common iliac arteries. In three patients who had an aortogram, evidence of flow limitation was found on the basis of the presence of aortic stenosis or occlusion. Treatment consisted of aortic stent graft deployment in one patient, direct aortic reconstruction in three patients, and observation in the remaining six patients. CONCLUSION: Although the natural history of isolated abdominal aortic dissection has not been well defined, our experience adds to the understanding of this rare process. Because aneurysmal degeneration can occur, close surveillance is indicated if definitive treatment is not used initially. Patients with ischemic symptoms and those with intractable pain need intervention, the nature of which should be based on risk profile and aortoiliac anatomy.     

Adenovirus Expressing a Bioluminescence Reporter Gene and cMAGI cell Assay for the Detection of HIV-1

We report a fast, highly sensitive method for detecting and testing drug resistance of M-tropic and T-tropic laboratory and primary HIV-1 isolates. cMAGI cells are infected with an adenovirus vector harboring the luciferase reporter gene controlled by HIV-1 Tat-responsive element, TAR. HIV-1 Tat production by HIV-1 chronically infected cells, or by cMAGI cells as early as two days after being acutely infected with HIV-1, is readily monitored in the presence or absence of antiviral drugs. This method is more sensitive than HIV-1 Tat dependant production of beta-galactosidase in the cMAGI cells. The fast answer, ease and sensitivity as well as the possibility of using this method in high throughput screening, makes it an very attractive tool for phenotypic detection of HIV-1 in clinical samples as well as a sensitive assay for monitoring drug resistant HIV-1 variants. This method can also be used for discovery of novel anti HIV-1 drugs.     

Evaluation of the efficacy of the transposed upper arm arteriovenous fistula: a single institutional review of 190 basilic and cephalic vein transposition procedures

INTRODUCTION: Although autogenous brachial-basilic upper arm transpositions (BVT) have been extensively utilized, there has been significant disparity in published patency rates. Very little is known about the efficacy of autogenous brachial-cephalic upper arm transpositions (CVT). We evaluated our experience with transposed upper arm arteriovenous fistulas (tAVF) in order to assess patency and identify factors that affect efficacy. We then compared our tAVF patients with a cohort of upper arm arteriovenous grafts (AVG). METHODS: A retrospective review was conducted of tAVF performed at our institution from 1998 to 2004. The tAVF group consisted of 119 BVT and 71 CVT procedures. We compared these with 164 AVG. tAVF were placed only for veins >/=2.5 mm in diameter by duplex ultrasonography. RESULTS: Mean follow-up was 28 months. With the exception of mean vein diameter, the patients in the BVT and CVT groups had similar demographic parameters and complication rates. Primary and secondary patency rates were 52% and 62% at 5 years for BVT and 40% and 46% at 5 years for CVT, respectively (P = NS). Multivariate analysis revealed that hemodialysis dependence at the time of fistula placement and history of previous upper arm access independently affected primary patency. History of upper torso dialysis catheters independently affected secondary patency. Comparison of the tAVF and AVG groups revealed that tAVF patients were significantly younger, more likely to be male, less likely to be African American (AA) and less likely to have a history of previous AV access. The primary patency rate for tAVF was significantly higher than for AVG: 48% vs 14% at 5 years (P < .001). The secondary patency rate for tAVF was also significantly higher than for AVG: 57% vs 17% at 5 years (P < .001). Among the tAVF procedures, 9% required one or more revisions to maintain secondary patency, compared to 51% with the AVG group (P < .001). Multivariate analysis revealed that presence of AVG and a history of previous upper arm access negatively affected primary and secondary patency. CONCLUSIONS: Autogenous BVT and CVT have similar, high patency rates. Transposed upper arm arteriovenous fistulas have higher patency rates than upper arm AVG and require significantly fewer revisions. Our data strongly support the contention that as long as the patient is a candidate for an upper arm tAVF, based on anatomical criteria, a tAVF should always be considered before an AVG.     

Incomplete distal renal tubular acidosis affects growth in children.

BACKGROUND: Incomplete distal renal tubular acidosis (idRTA) is recognized as an underlying aetiology in recurrent nephrolithiasis. Until the recently reported high prevalence of idRTA in adults with osteoporosis, the effect of idRTA on skeletal parameters was not known. We hypothesize that idRTA has a potential to affect height in the paediatric population. METHODS: In a cross-sectional study, the children with posterior urethral valves (PUV), with normal estimated glomerular filtration rates, were evaluated for idRTA and complete dRTA. The idRTA evaluation was done by short ammonium chloride acidification test. The height standard deviation scores (SDS) in the idRTA group were compared with PUV children without dRTA, with complete dRTA, and to age and gender matched controls with no renal issue (n = 50). RESULTS: The idRTA group (n = 17) manifested a significantly lower mean height SDS (-1.94 +/- 0.41 vs -0.46 +/- 0.28; P < 0.001) and a higher short stature prevalence (height SDS below 2) (18% vs 0; P = 0.06) as compared with those without dRTA (n = 23). The matched controls showed a significantly higher height SDS as compared with the idRTA group (-0.39 +/- 0.25 vs -1.94 +/- 0.41; P < 0.001). As compared with the complete dRTA group (n = 9), the children with idRTA did have significantly higher height SDS (-1.94 +/- 0.41 vs -5.31 +/- 1.95; P = 0.002), and a lower short stature prevalence (18% vs 78%; P = 0.001). On multivariate analysis, dRTA was significantly associated with the height SDS (= -0.88; P < 0.001). CONCLUSIONS: Incomplete dRTA affects height in children. This observation needs validation in longitudinal studies.     

The interactive electrode localization utility: software for automatic sorting and labeling of intracranial subdural electrodes

Purpose

Existing methods for sorting, labeling, registering, and across-subject localization of electrodes in intracranial encephalography (iEEG) may involve laborious work requiring manual inspection of radiological images.

Methods

We describe a new open-source software package, the interactive electrode localization utility which presents a full pipeline for the registration, localization, and labeling of iEEG electrodes from CT and MR images. In addition, we describe a method to automatically sort and label electrodes from subdural grids of known geometry.

Results

We validated our software against manual inspection methods in twelve subjects undergoing iEEG for medically intractable epilepsy. Our algorithm for sorting and labeling performed correct identification on 96% of the electrodes.

Conclusions

The sorting and labeling methods we describe offer nearly perfect performance and the software package we have distributed may simplify the process of registering, sorting, labeling, and localizing subdural iEEG grid electrodes by manual inspection.

     

Percutaneous Endovascular Repair of Abdominal Aortic Aneurysm with Coexisting Horseshoe Kidney: Technical Aspects and Review of the Literature

Surgical repair of abdominal aortic aneurysms (AAAs) with coexisting horseshoe kidney (HSK) is technically challenging because of complex anatomy. Endovascular repair has emerged as a common approach to AAA repair and represents a valid alternative in selected patients with AAA and concomitant congenital renal anomalies. We report a case of successful percutaneous endovascular repair in a patient with coexistent AAA and HSK. Careful preoperative planning is essential in successful endovascular management of abdominal aneurysms in these patients.