MRI estimation of total renal volume demonstrates significant association with healthy donor weight.

PURPOSE: The purpose of this study was to correlate total renal volume (TRV) calculations, obtained through the voxel-count method and ellipsoid formula with various physical characteristics. MATERIALS AND METHODS: MRI reports and physical examination from 210 healthy kidney donors (420 kidneys), on whom renal volumes were obtained using the voxel-count method, were retrospectively reviewed. These values along with ones obtained through a more traditional method (ellipsoid formula) were correlated with subject height, body weight, body mass index (BMI), and age. RESULTS: TRV correlated strongly with body weight (r=0.7) and to a lesser degree with height, age, or BMI (r=0.5, -0.2, 0.3, respectively). The left kidney volume was greater than the right, on average (p<0.001). The ellipsoid formula method over-estimated renal volume by 17% on average which was significant (p<0.001). CONCLUSIONS: Body weight was the physical characteristic which demonstrated the strongest correlation with renal volume in healthy subjects. Given this finding, a formula was derived for estimating the TRV for a given patient based on the his or her weight: TRV = 2.96 x weight (kg) + 113+/-64.

Preoperative selective venous sampling for nonlocalizing parathyroid adenomas.

INTRODUCTION: Preoperative parathyroid adenoma localization allows for a minimally invasive surgical approach. Current methods used for adenoma localization include ultrasound, sestamibi scan, and occasionally magnetic resonance imaging (MRI). In cases in which an adenoma is not localized after a radiologic work-up, the surgeon must perform a four-gland exploration. Preoperative selective venous sampling (SVS) has been described as a safe and clinically effective method to localize a parathyroid adenoma after failed exploration. The purpose of this study was to evaluate the efficacy of SVS as a primary localization technique in cases where conventional localization techniques have failed. MATERIALS AND METHODS: Fourteen patients with nonlocalizing parathyroid adenomas after ultrasonography, sestamibi scanning, and MRI were retrospectively reviewed. Eight patients underwent SVS prior to surgery and six patients underwent a four-gland neck exploration without preoperative SVS. The two groups were assessed for accuracy of the SVS in localizing the adenoma, operative time, length of hospitalization, and complications. RESULTS: All of the patients in the study underwent successful uncomplicated surgical parathyroidectomy. The SVS proved accurate in preoperatively localizing the adenoma in 7 of 8 patients and allowed for a minimally invasive approach in 87% of patients. The mean operative time was 33 minutes for the SVS group and 67 minutes in the non-SVS group. None of the patients in either group experienced procedural complications. CONCLUSION: This study suggests that preoperative SVS may represent a safe and effective method of preoperatively localizing the nonlocalized parathyroid adenoma. In cases where conventional radiologic techniques fail to localize an adenoma, SVS may obviate the need for a four-gland exploration.

Inferior mesenteric artery embolization before endovascular aneurysm repair: technique and initial results.

PURPOSE: To report a single center's technique and initial results in the preoperative embolization of the inferior mesenteric artery (IMA) before endovascular aneurysm repair (EVAR). MATERIALS AND METHODS: Over a 3-year period, 102 patients at a single clinical site, including 86 men and 16 women aged 54-93 years (mean, 75 years), were found to have a patent IMA on computed tomographic (CT) angiography before EVAR. Coil embolization was performed after subselective catheterization with use of microcoils placed in the IMA proximal to the origin of the left colic artery. All patients in whom the IMA was visualized on flush aortography and successfully accessed underwent embolization. One month and 6 months after surgery, results in this cohort were retrospectively compared with those from a similar group of patients who underwent EVAR during the same period. These patients had patent IMAs on preoperative CT angiography but did not undergo embolization as a result of nonvisualization during flush aortography. All patients underwent EVAR with bifurcated modular devices with proximal transrenal fixation. All patients underwent postoperative follow-up with multiphase CT angiography to detect the presence of endoleak. Six-month follow-up data were available for 18 patients who underwent embolization and 54 patients who did not. Change in sac diameter was compared in these patients. RESULTS: Embolization was technically successful in 30 of 32 patients (94%) in whom it was attempted. There were no complications. At 1-month follow-up, five of 30 patients in the embolization group were noted to have a type II endoleak (17%). None of the endoleaks in this group were related to the IMA. The group with patent IMAs who did not undergo preoperative embolization had a 42% incidence of type II endoleak (P < .05). At 6 months after surgery, three of 18 patients who had undergone embolization (17%) had a type II endoleak, compared with 26 of 54 in the other group (48%; P < .05). Among the patients in whom 6-month data were available, mean changes in sac diameter were -5.2 mm (range, -24 to 2 mm) in the embolized group and -2.1 mm (range, -19 to 8 mm) in the nonembolized group. CONCLUSION: These initial results demonstrate that embolization of the IMA with subselective microcoils before EVAR is a safe and effective procedure to reduce the incidence of type II endoleaks. The data also suggest that preoperative embolization of the IMA is associated with greater shrinkage of aneurysm sac diameter at 6 months.

Guide wire perforation leading to fatal perirenal hemorrhage from transcortical collaterals after renal artery stent placement.

After successful renal artery angioplasty and stent placement, a patient in a fully anticoagulated state developed hypotension and flank pain. Review of the intraprocedural angiogram demonstrated transcortical position of the guide wire. Computed tomography of the abdomen revealed a large perinephric hematoma. Although only a single renal artery branch was accessed with the guide wire during stent placement, subsequent emergent angiography revealed extravasation from multiple capsular branches. Renal artery embolization failed to control the hemorrhage. The patient's course rapidly deteriorated and he ultimately died. The unique angiographic finding and proposed mechanism of this fatal complication are described and discussed.

Minimally invasive management of an advanced abdominal pregnancy.

BACKGROUND: Advanced abdominal pregnancy is a rare, life-threatening condition that presents a number of challenges. CASE: A 29-year-old primigravida with 10 years of secondary infertility and a previous tuboplasty had a 21-week abdominal pregnancy treated with preoperative arterial embolization before laparoscopically assisted fetal delivery. Postoperatively, 4 cycles of methotrexate were administered at 50 mg/m2 intramuscularly every 3 weeks for the retained abdominal placenta. Subsequent spontaneous conception occurred, and a live, full-term infant was delivered by cesarean delivery 17 months later. No adverse sequelae were found during long-term follow-up. CONCLUSION: This report demonstrates successful minimally invasive management of an advanced abdominal pregnancy with a multimodal approach that included preoperative arterial embolization, laparoscopically assisted delivery, and judicious use of postoperative methotrexate.

Advances in angiography and their impact on endovascular therapy.

Transvascular therapy has progressed rapidly due to improvements in imaging equipment and endovascular devices. Interventional fluoroscopic equipment and portable machines are able to produce high-resolution digital images in well-lighted procedure rooms. Catheters and guidewires are now available in a variety of shapes, diameters and lengths, allowing entry into distal, small, and tortuous vessels. This in turn permits targeted local therapy of tumors and bleeding sites, as well as endovascular treatment of diseased vessels.

Endovascular stent graft repair of abdominal and thoracic aortic aneurysms: a ten-year experience with 817 patients.

OBJECTIVE: On November 23, 1992, the first endovascular stent graft (ESG) repair of an aortic aneurysm was performed in North America. Following the treatment of this patient, we have continued to evaluate ESG over the past 10 years in the treatment of 817 patients. SUMMARY AND BACKGROUND DATA: Abdominal (AAA) or thoracic (TAA) aortic aneurysms are a significant health concern traditionally treated by open surgical repair. ESG therapy may offer protection from aneurysm rupture with a reduction in procedure morbidity and mortality. METHODS: Over a 10-year period, 817 patients were treated with ESGs for AAA (723) or TAA (94). Patients received 1 of 12 different stent graft devices. Technical and clinical success of ESGs was reviewed, and the incidence of procedure-related complications was analyzed. RESULTS: The mean age was 74.3 years (range, 25-95 years); 678 patients (83%) were men; 86% had 2 or more comorbid medical illnesses, 67% of which included coronary artery disease. Technical success, on an intent-to-treat basis was achieved in 93.8% of patients. Primary clinical success, which included freedom from aneurysm-related death, type I or III endoleak, graft infection or thrombosis, rupture, or conversion to open repair was 65 +/- 6% at 8 years. Of great importance, freedom from aneurysm rupture after ESG insertion was 98 +/- 1% at 9 years. There was a 2.3% incidence of perioperative mortality. One hundred seventy five patients died of causes not related to their aneurysm during a mean follow-up of 15.4 months. CONCLUSIONS: Stent graft therapy for aortic aneurysms is a valuable alternative to open aortic repair, especially in older sicker patients with large aneurysms. Continued device improvements coupled with an enhanced understanding of the important role of aortic pathology in determining therapeutic success will eventually permit ESGs to be a more durable treatment of aortic aneurysms.

Recurrent portal hypertension after composite liver/small bowel transplantation.

Late technical complications of composite liver/small bowel transplantation procedures are often complex and have not been well defined. Here we describe the unusual presentation and management of two cases of recurrent thrombocytopenia due to hypersplenism resulting from portacaval shunt stenosis. Both patients presented with portal hypertension late after composite liver/small bowel transplantation. One patient presented with recurrent bouts of upper gastrointestinal hemorrhage and was ultimately found to have a stenosis of her native portacaval shunt. After unsuccessful balloon dilatation of the anastomosis, a successful side-to-side distal splenorenal shunt was performed. The second patient presented with severe thrombocytopenia, the etiology of which was determined to be a short segment occlusion of the inferior vena cava between the native portacaval shunt and the piggyback outflow anastomosis of the liver graft. Total caval occlusion prevented balloon dilatation; the patient was relisted for transplantation but died of chronic rejection four months later. Recurrent portal hypertension is challenging in patients who have had combined liver/small bowel transplantation. Surgeons performing intestinal transplantation need to be increasingly aware of these possible late complications.

Thoracic duct injury associated with left internal jugular vein catheterization: anatomic considerations.

Ultrasound (US)-guided cannulation of the internal jugular vein (IJV) has become the preferred approach for venous access as a result of its higher success rate and lower incidence of complications. This report describes a case of thoracic duct injury during US-guided left IJV catheterization. The normal and variant anatomy of the thoracic duct in the neck is illustrated.

Radiologic diagnosis and treatment of gastrointestinal hemorrhage and ischemia.

Major breakthroughs in catheter, guidewire, and other angiographic equipment currently allow interventional radiologists to diagnose massive life-threatening upper and lower GI hemorrhage and to stop the bleeding safely and effectively using superselective catheterization and microcoil embolization. Similarly, the interventional radiologist can treat acute intestinal ischemia safely and effectively with selective catheterization and papaverine administration and treat chronic mesenteric ischemia by percutaneous angioplasty and stent placement. A multidisciplinary approach, including the gastroenterologist, radiologist, and surgeon, is critical in managing GI bleeding and intestinal ischemia, particularly in patients at high risk or presenting as diagnostic dilemmas.