David J. Spinosa

Percutaneous transluminal angioplasty and stenting in the treatment of chronic mesenteric ischemia: results and longterm followup

BACKGROUNDnThe purpose of this study was to review the results of percutaneous transluminal angioplasty (PTA), stenting, or both in the treatment of patients who present with symptoms and angiographic findings most consistent with chronic mesenteric ischemia.nnnSTUDY DESIGNnA retrospective analysis of 33 consecutive patients from a single institution who underwent PTA, stenting, or both for treatment of symptoms most characteristic of chronic mesenteric ischemia was performed.nnnRESULTSnThere were 12 men and 21 women with a mean age of 63 years (range 40 to 89 years). Median weight loss was 28 lb (range 6 to 80 lb). Postprandial pain was present in 88% of the patients (29 of 33). All lesions treated were stenoses. PTA alone was performed in 21 patients (32 vessels), and PTA and stenting were performed in 12 patients (15 vessels). PTA was technically successful in 26 of 32 vessels (81.3%); PTA plus stenting was technically successful in 15 of 15 vessels (100%) (p = 0.073). Complete alleviation of symptoms occurred immediately in 27 of the patients (82%), and 2 patients (6%) had significant improvement in symptoms. There were four immediate clinical failures (12%): two patients were found to have occult malignancy and one had immediate relief of symptoms after surgical release of the median arcuate ligament. Followup data were obtained in all patients with clinically successful procedures (mean 38 months, median 25 months, range 1 to 123 months). Angiographic followup was available in 52% of the patients (15 of 29), at a mean of 20 months. The primary longterm clinical success rate was 83.3% (24 of 29). Four of the five patients with recurrent symptoms were successfully retreated with endovascular therapy. The primary assisted longterm clinical success rate was 96.6% (28 of 29). The 5-year survival rate was 76.1%. Major complications occurred in 13% of the procedures, with a 30-day mortality rate of 0%.nnnCONCLUSIONnEndovascular therapy for treatment of mesenteric arterial stenoses is effective in the treatment of patients with symptoms and angiographic findings characteristic of chronic mesenteric ischemia.

Simultaneous antegrade and retrograde access for subintimal recanalization of peripheral arterial occlusion.

Subintimal recanalization can be a useful procedure in selected patients with severe peripheral vascular disease with tissue loss or rest pain and limited surgical bypass options. Technical failure occurs in approximately 20% of patient who undergo percutaneous intentional extraluminal recanalization due to inability to reenter the distal true lumen. A technique to improve technical success when performing subintimal recanalization when there is failure to reenter the distal true lumen or possibly when there is a limited segment of patent distal target vessel for reentry is proposed. Further evaluation of this technique is necessary to confirm its safety and determine its technical and clinical success.

MR angiography of the renal arteries

During, the past decade. MRA has evolved from an cxperimental technique into the modality of choice for the noninvasive evaluation of renovascular disease. The recent widespread application of MRA for these indications has been driven primarily by the advent of 3D contrast-enhanced MRA. which provides a fast, reliable technique for imaging large vascular territories and generates images, after postprocessing, similar in appearance to digital subtraction angiography. The cross-sectional volumetric nature of contrast-enhanced MRA affords some advantages over conventional catheter angiography. Although 3D contrast-enhanced MRA forms the backbone of vascular MR studies, several adjunctive sequences are employed to maximize the diagnostic yield of the examination. For example. flow-dependant imaging is used to complement the morphologic images of contrast-enhanced MRA by providing hemodynamic information. As such, MRA is unique among noninvasive imaging modalities in that it offers a comprehensive evaluation of anatomy and function. The availability and reliability of MRA extend renal artery screening to a wider spectrum of patients. Current applications of renal MRA range from detection of renal artery stenosis to evaluation for renal transplant donors.

Selection of Stents for Treating Iliac Arterial Occlusive Disease

Intravascular stents play an increasingly important role in the treatment of iliac artery occlusive disease and their use has expanded the indications for percutaneous endoluminal therapies. The past several years have seen a sharp increase in the number of commercially available covered and uncovered stents. Knowledge of their design and mechanical properties is crucial for selecting the appropriate stent for a particular type of lesion. In this article, the indications for and results of iliac artery stent placement are reviewed and the various characteristics of the currently available stents that may influence operator choice for use in specific lesions are discussed.

Primary sarcoma of the distal abdominal aorta: CT angiography findings

Primary aortic angiosarcomas are extremely rare. Clinically and radiographically, they mimic atherosclerosis and atheroembolic disease. For a definitive diagnosis, histologic evaluation of the tumor or of peripheral emboli is required. The imaging findings are frequently nonspecific and in most published cases did not allow a definitive preoperative diagnosis. This is the first report of the computed tomographic angiographic findings of a primary intimal abdominal aortic sarcoma and a review of previously described imaging findings in these tumors.

MR angiography of the mesenteric vasculature

MRA has evolved from a research tool to a robust clinical diagnostic modality. In many centers worldwide, it is the technique of choice for evaluating patients with suspected CMI, assessing operability of patients with pancreatic cancer, and investigating the portal system. Evolving indications include the assessment of liver transplant patients before and after transplant and of living related liver transplant donors. The search for the bleeding source in patients with gastrointestinal hemorrhage may be an indication in the future, once intravascular contrast agents become available.

Gadolinium-based contrast agents in angiography and interventional radiology.

Gadolinium is useful as an alternative contrast agent for diagnostic angiographic and interventional procedures in patients with renal insufficiency or a history of a severe reaction to iodinated contrast material. Gadolinium usually is used as a problem solver to answer specific diagnostic questions or guide interventional procedures that cannot adequately be defined with CO2 angiography. Because of dose limitations with Gd, careful planning is required prior to its use with angiography or interventional procedures.

Utility of percutaneous intervention in the management of tunneled hemodialysis catheters.

nA variety of interventional techniques have beenndeveloped to restore function to dysfunctional tunneled hemodialysisncatheters (THC). The relative efficacies of these techniques werenevaluated retrospectively to determine which therapy might be mostnbeneficial. The records of malfunctioning THCs referred toninterventional radiology between November 1995 and December 1999 werenretrospectively reviewed. Dysfunctional THCs were studied using DSAnimages obtained while injecting contrast through the lumens of thenTHCs. The interventions performed were categorized into 1 of 5 groups:nno treatment or conservative measures such as vigorous flushing;nadvancing a guidewire through the THC to reposition the catheter tip ornto dislodge a small thrombus; catheter exchange over a guidewire;nfibrin stripping of the THC using a loop snare; or prolonged (4 or morenhr) direct thrombolytic infusion. A Cox Proportional Hazards model wasndeveloped to compare the rate of failure among the procedures. Therenwere 340 THC studies. The catheters were managed as follows: 93npatients received conservative management only, 15 had a guidewirenadvanced through the catheter, 147 underwent catheter exchange, 62 werentreated with a fibrin stripping procedure, and 23 received anthrombolytic infusion. Estimated 30-day patency rates for THCs weren38.2% for conservative management, 30.9% for guidewire manipulationnof catheter tip, 53.6% for catheter exchange, 76.1% for fibrinnstripping, and 69.8% for thrombolytic infusion. Differences among thentreatments were observed (p < 0.01) andnpairwise comparisons were made among the treatment groups. Failurenrates were significantly higher in the catheter exchangen(p <0.01) and guidewire manipulation atncatheter tip (p <0.01) groups when comparednwith the fibrin stripping group. The catheter exchange and guidewirenmanipulation groups also experienced higher rates of failure whenncompared with the thrombolytic infusion group, although the differencesnwere not statistically significant (p = 0.08, pn= 0.17, respectively). Four procedure-related complicationsnrequiring hospitalization or other intervention occurred. Three ofnthese were in the catheter exchange group with one incidence of sepsis,none drug reaction, and one hematoma. Fibrin stripping and thrombolyticninfusion provided the greatest efficacy in the treatment of poorlynfunctioning THCs, but all therapies demonstrated wide-ranging results.nCentral line exchanges did not provide a superior secondary patency andnexperienced more complications.n

Magnetic resonance urography for the assessment of potential renal donors: Comparison of the RARE technique with a low-dose gadolinium-enhanced magnetic resonance urography technique in the absence of pharmacological and mechanical intervention

The aim of this study was to determine whether magnetic resonance urography without pharmacological (diuretic) stimulation and mechanical compression allows conclusive evaluation of the urinary system in potential renal donors. In 28 consecutive patients magnetic resonance urography (MRU) was performed on a 1.5-T system. Two techniques, rapid acquisition with relaxation enhancement (RARE) and a gadolinium (Gd)-enhanced 3D fast low angle shot (FLASH) sequence were compared in the absence of adjunctive measures. Two reviewers assessed image quality, presence of artifacts and completeness of visualization of the collecting systems and ureters. Among the 53 MR urograms, there was no difference in image quality and presence of artifacts between RARE and Gd-MRU. Despite high image quality, visualization of the urinary collecting system was insufficient. Continuous visualization from the collecting system to the distal ureter was demonstrated bilaterally in only 14% of the RARE and 26% of Gd-enhanced MR urograms, respectively. Overall, Gd-enhanced MRU was superior to the RARE technique in displaying the segments of the urinary collecting system, but this difference was not found to be statistically significant. Neither the RARE technique nor the gadolinium-enhanced MRU technique is accurate enough to allow the evaluation of the collecting system and ureters in potential renal donors in the absence of pharmacological intervention and compression.

Body MR venography

MRV offers unique diagnostic possibilities for detection and characterization of venous disease. It allows evaluation of perivascular and vascular anatomy, evolution of thromboembolic events, and assessment of vascular flow. MRI is a diagnostic tool that can be tailored for a variety of clinical dilemmas, not only DVTs. Continued improvements in hardware and software will expand the role of MRV.