Endoleak after endovascular repair of abdominal aortic aneurysm.

PURPOSE: We sought to assess the role of endovascular techniques in the management of perigraft flow (endoleak) after endovascular repair of an abdominal aortic aneurysm. METHOD: We performed endovascular repair of abdominal aortic aneurysm in 114 patients, using a variety of Gianturco Z-stent-based prostheses. Results were evaluated with contrast-enhanced computed tomography (CT) at 3 days, 3 months, 6 months, 12 months, and every year after the operation. An endoleak that occurred 3 days after operation led to repeat CT scanning at 2 weeks, followed by angiography and attempted endovascular treatment. RESULTS: Endoleak was seen on the first postoperative CT scan in 21 (18%) patients and was still present at 2 weeks in 14 (12%). On the basis of angiographic localization of the inflow, the endoleak was pure type I in 3 cases, pure type II in 9, and mixed-pattern in 2. Of the 5 type I endoleaks, 3 were proximal and 2 were distal. All five resolved after endovascular implantation of additional stent-grafts, stents, and embolization coils. Although inferior mesenteric artery embolization was successful in 6 of 7 cases and lumbar embolization was successful in 4 of 7, only 1 of 11 primary type II endoleaks was shown to be resolved on CT scanning. There were no type III or type IV endoleaks (through the stent-graft). Endoleak was associated with aneurysm dilation two cases. In both cases, the aneurysm diameter stabilized after coil embolization of the inferior mesenteric artery. There were two secondary (delayed) endoleaks; one type I and one type II. The secondary type I endoleak and the associated aneurysm rupture were treated by use of an additional stent-graft. The secondary type II endoleak was not treated. CONCLUSIONS: Type I endoleaks represent a persistent risk of aneurysm rupture and should be treated promptly by endovascular means. Type II leaks are less dangerous and more difficult to treat, but coil embolization of feeding arteries may be warranted when leakage is associated with aneurysm enlargement.

Analysis of initial CT findings after endovascular repair of abdominal aortic aneurysm.

PURPOSE: To determine the spectrum and frequency of specific computed tomographic (CT) findings in the acute period after endovascular repair of abdominal aortic aneurysm (AAA). MATERIALS AND METHODS: CT images obtained 1--3 days after endograft placement were evaluated in 88 patients. The images were analyzed for stent position, appearance of endograft components, perigraft leak, and postoperative findings including air and acute thrombus within the aneurysm and air surrounding the femoral-femoral bypass graft. Findings that could be misinterpreted as perigraft leak were evaluated. RESULTS: Fifteen (17%) of 88 patients had perigraft leak in the acute postoperative period. The bare segment of the proximal self-expanding stent covered one or both renal arteries in 54 (61%) patients. One patient had CT evidence of renovascular compromise. Postoperative air was within the aneurysmal sac in 51 (58%) patients and surrounded the femoral-femoral bypass graft in 67 (94%) of 71 patients in whom the grafts were evaluated with CT. Mottled attenuation within the aneurysmal sac was seen in 50 (57%) patients. Forty-six (52%) patients had calcifications within longstanding thrombus. In 31 (35%) patients, findings that could have been misinterpreted as perigraft leak were identified. CONCLUSION: Accurate analysis of CT findings after endovascular AAA repair requires careful review of all available CT images (preprocedural and pre- and postcontrast) and clear understanding of specific stent-graft components and placement.

Colorectal neoplasia: performance characteristics of CT colonography for detection in 300 patients.

PURPOSE: To determine the sensitivity and specificity of computed tomographic (CT) colonography for colorectal polyp and cancer detection by using colonoscopy as the reference standard. MATERIALS AND METHODS: Three hundred patients underwent CT colonography followed by standard colonoscopy. Bowel preparation consisted of magnesium citrate and polyethylene glycol. After colonic air insufflation, patients underwent scanning in the supine and prone positions with 3-mm collimation during a single breath hold. The transverse CT images, sagittal and coronal reformations, and three-dimensional endoluminal images were interpreted by two radiologists independently, and then a consensus reading was performed. CT colonographic findings were correlated with standard colonoscopic and histologic findings. RESULTS: The overall sensitivity and specificity of CT colonography for polyp detection were 90.1% (164 of 182) and 72.0% (85 of 118), respectively. By using direct polyp matching, the overall sensitivity was 69.7% (365 of 524). The sensitivity was 90% (74 of 82) for the detection of polyps 10 mm or larger, 80.1% (113 of 141) for polyps 5.0-9.9 mm, and 59.1% (178 of 301) for polyps smaller than 5 mm. The sensitivity was 94% (64 of 68) for the detection of adenomas 10 mm or larger, 82% (72 of 88) for adenomas 5.0-9.9 mm, and 66.9% (95 of 142) for adenomas smaller than 5 mm. CT colonography was used to identify all eight carcinomas. CONCLUSION: CT colonography has excellent sensitivity for the detection of clinically important colorectal polyps and cancer.

Aortic stent-grafts in patients with renal transplants.

PURPOSE: To report the endovascular treatment of abdominal aortic aneurysms (AAA) in 2 patients with pelvic renal transplants. METHODS AND RESULTS: Two men with multiple comorbidities and pelvic transplant kidneys underwent endovascular AAA repair using an aortomonoiliac system with femorofemoral bypass grafting. The arterial end-to-side anastomosis in both patients was to the external iliac artery. Tapered aortomonoiliac grafts were fashioned from Gianturco Z-stents covered with Dacron graft material and implanted with the distal attachment site in the iliac system ipsilateral to the transplant kidney arterial anastomosis. The body of the stent-graft was reinforcement with a Wallstent in each case before the contralateral common iliac artery was occluded and the cross-femoral bypass constructed. Both patients recovered uneventfully from the procedure and are free of endoleak or other complications related to their aneurysm repair at 7 and 34 months. CONCLUSIONS: The presence of a pelvic renal transplant in a patient undergoing endovascular AAA repair increases the complexity of procedural planning and endograft implantation, but a good outcome can be achieved.

Endovascular repair of a presumed aortoenteric fistula: late failure due to recurrent infection.

PURPOSE: To describe a case of presumed aortoduodenal fistula that was treated by endovascular implantation of a stent-graft. METHODS AND RESULTS: A 76-year-old man was transferred from another hospital where he had been treated for upper gastrointestinal hemorrhage over a 2-month period. Ten years previously, he had undergone aortobifemoral bypass, the right limb of which recently thrombosed. At the time of transfer, computed tomographic scanning showed a large false aneurysm between the aorta and the duodenum. Endoscopy disclosed mucosal erosions in the fourth portion of the duodenum. Following implantation of 2 overlapping stent-grafts, the bleeding ceased and the false aneurysm disappeared. At no time did the patient have a fever. The patient initially did well, but 8 months after treatment, he presented with fever and chills. Recurrent infection had caused erosion of the aorta so that a large portion of the stent-graft was visible from the duodenum. The infected graft and stent-grafts were removed in a two-part operation, from which the patient recovered satisfactorily. CONCLUSIONS: Endovascular stent-grafts may have a role to play in the management of aortoduodenal fistula, if only as a temporary measure to control bleeding.

Endovascular aneurysm repair in high-risk patients.

PURPOSE: The purpose of this study was to evaluate the role of endovascular aneurysm repair in high-risk patients. METHODS: The elective endovascular repair of infrarenal aortic aneurysm was performed in 116 high-risk patients with either custom-made or commercial stent grafts. The routine follow-up examination included contrast-enhanced computed tomography (CT) before discharge, at 3, 6, and 12 months, and annually thereafter. Patients with endoleak on the initial CT underwent re-evaluation at 2 weeks. Those patients with positive CT results at 2 weeks underwent endovascular treatment. RESULTS: Endovascular repair was considered feasible in 67% of the patients. The mean age was 75 years, and the mean aneurysm diameter was 6.3 cm. The American Society of Anesthesiologists grade was II in 3.4%, III in 65.5%, IV in 30.1%, and V in 0.9%. There were no conversions to open repair. Custom-made aortomonoiliac stent grafts were implanted in 77.6% of the cases, custom-made aortoaotic stent grafts in 11.2%, and commercial bifurcated stent grafts in 11.2%. The 30-day rates of mortality, major morbidity, and minor morbidity were 3.4%, 20.7%, and 12%, respectively, in the first 58 patients and 0%, 3.4%, and 3.4%, respectively, in the last 58. The late complications included five cases of stent graft kinking, two cases of femorofemoral graft occlusion, and three cases of proximal stent migration, one of which led to aneurysm rupture. At 2 weeks after repair, endoleak was present in 10.3% of the cases. All the type I (direct perigraft) endoleaks underwent successful endovascular treatment, whereas only one type II (collateral) endoleak responded to treatment. The technical success rate at 2 weeks was 86.2%, and the clinical success rate was 96.6%. The continuing success rate was 87.9%. Seventeen patients died late, unrelated deaths. CONCLUSION: Endovascular aneurysm repair is safe and effective in patients at high risk, for whom it may be the preferred method of treatment.

Aortomonoiliac endovascular grafting combined with femorofemoral bypass: an acceptable compromise or a preferred solution?

The relative merits of aortomonoiliac and bifurcated stent-graft configurations depend on the patient's arterial anatomy and clinical status. Aortomonoiliac stent-grafts are simple to make, simple to insert, and versatile. They are most useful when the iliac artery anatomy is severely distorted and the patient is old, sick, and inactive. The main problems with this approach are all consequences of femorofemoral bypass. The bifurcated stent-graft is the preferred alternative in healthy patients, because it ensures flow to both common iliac arteries, thereby eliminating the need for femorofemoral bypass. However, bifurcated stent-grafts and their delivery systems are difficult to make and difficult to deploy, especially when the iliac anatomy is distorted or emergency circumstances preclude preoperative sizing. This article addresses the advantages and disadvantages of the aortomonoiliac graft.

The usefulness of glucagon hydrochloride for colonic distention in CT colonography.

OBJECTIVE: The purpose of this study was to compare colonic distention with and without glucagon hydrochloride during CT colonography. SUBJECTS AND METHODS: CT colonography using single breath-hold, thin-section helical technique was performed on 60 patients who were in the supine and prone positions. Magnesium citrate and polyethylene glycol were used for bowel preparation. Colonic air insufflation averaged 30 bulb compressions. Thirty-three patients received IV glucagon (1 mg), and 27 patients did not. The colon was divided into eight segments, and the adequacy of the distention of each segment was evaluated. Overall colonic distention scores, defined as the number of inadequately distended segments (0-8), were recorded for the supine, prone, and combined positions. In the combined position, inadequate distention was defined as identical segments that were inadequately distended in both positions. RESULTS: A total of 960 segments were evaluated: 528 segments in the glucagon group and 432 segments in the nonglucagon group. In the glucagon group, 444 segments (84.1%) were adequately distended. In the nonglucagon group, 365 segments (84.5%) were adequately distended. The median and range for overall colonic distention scores in the supine, prone, and combined positions were 1 (0-3), 1 (0-3), and 0 (0), respectively, for the glucagon group and 1 (0-6), 1 (0-6), and 0 (0-1), respectively, for the nonglucagon group. We found no statistically significant difference in overall colonic distention between the glucagon group and the nonglucagon group for the supine (p = .84), prone (p = .15), or combined (p = .28) positions. CONCLUSION: Glucagon administration before CT colonography does not improve colonic distention.

Abdominal aortic aneurysm in high-risk patients: short- to intermediate-term results of endovascular repair.

PURPOSE: To assess the safety and efficacy of endovascular repair of abdominal aortic aneurysm in high-risk patients during the short to intermediate term. MATERIALS AND METHODS: Endovascular aneurysm repair was performed in 50 patients considered too high risk for conventional repair. Stent-grafts were inserted through surgically exposed femoral arteries with fluoroscopic guidance. The anesthetic technique was epidural in 36 patients, general in 12, and local in two. Aortouniiliac stent-grafts were inserted in 42 patients and aortoaortic in eight. RESULTS: There were no deaths and no conversions to open surgical repair. The primary success rate (complete aneurysm exclusion according to CT criteria) was 88% (44 of 50). The secondary, clinical, and continuing success rates were all 98% (49 of 50). Surgical time was 196 minutes +/- 67 (mean +/- SD), blood loss was 284 mL +/- 386, and volume of contrast material administered was 153 mL +/- 64. The time from the end of the surgery to resumption of a normal diet was 0.58 days +/- 0.56, to ambulation was 1.22 days +/- 0.77, and to discharge from the hospital was 3.63 days +/- 1.60. Wound problems accounted for the majority of complications. There were no instances of pulmonary failure, renal failure, stent-graft migration, or late leakage. CONCLUSION: Endovascular repair of abdominal aortic aneurysm is feasible in two-thirds of high-risk patients, with a low mortality and high success rate during the short to intermediate term.

Human immunodeficiency virus infection and hepatitis: biosafety in radiology.

Radiologists frequently perform invasive diagnostic and therapeutic procedures involving needles and/or vascular access, and often they do so in darkened rooms. Therefore, they are at risk of exposure to blood-borne pathogens. The risk of HIV infection with a single sharp injury is low (0.3%), and on average 99.7% of exposures will not result in infection. However, this seroconversion rate is increased when a high volume of blood or a high concentration of virus is inoculated, and it is decreased by 79% when postexposure prophylaxis is used. An estimated 800,000 needle-stick injuries and other injuries from sharp objects to health care workers occur annually in the United States (25). Approximately 16,000 of these involve HIV-contaminated blood, and even more are contaminated with HBV or HCV (46). Needle-stick injury therefore poses the single greatest risk to health care workers regarding occupational transmission of HIV. Because most patients in the radiology department have an unknown HIV or hepatitis serostatus, all patients should be regarded as potentially infectious, and precautions should be universal. In fact, the 1991 OSHA ruling made compliance with the CDC Universal Precautions Guidelines the enforceable national standard. Real-time oral communication among all members of the radiology team and scrupulous attention to safe technique are absolutely essential. Radiologists are not in agreement regarding the use of precautions against injury with a sharp object and splashing (47-50). Many have adapted some of their habits to conform well to the CDC and OSHA guidelines regarding universal precautions, but some remain skeptical regarding the risk of exposure to themselves. Consequently, in some areas resistance to the above recommendations persists. However, the data to date provide a compelling argument for protection against occupational exposure to blood either by percutaneous sharp injury or splashing on mucous membranes or interrupted skin. A number of resources were made available in early 1997 for easy access to the most current data regarding occupational transmission of HIV or hepatitis. For instance, the CDC has a World Wide Web site (http://www.cdc.gov) and a facsimile information service through the Hospital Infections Program directory (telephone 404-332-4565). Also, the National AIDS Clearinghouse can be reached by telephone (800-458-5231), as can the HIV/AIDS Treatment Information Service (800-448-0440). The postexposure prophylaxis protocol used at the University of California, San Francisco, can be reviewed by visiting its World Wide Web site at http://epi-center.ucsf.edu. And up-to-date information is available to both Veterans Administration and other health care staff worldwide by J. Michael Howe, MSLS, of the AIDS Information Center, a service of the VA HIV/AIDS National Training Program, located at the Veterans Administration Medical Center, San Francisco, University of California, San Francisco (hivinfo@itsa.ucsf.edu).

Endoscopic sclerotherapy compared with percutaneous transjugular intrahepatic portosystemic shunt after initial sclerotherapy in patients with acute variceal hemorrhage. A randomized, controlled trial.

BACKGROUND: Hemorrhage from esophageal varices remains a substantial management problem. Endoscopic sclerotherapy was preferred for more than a decade, but fluoroscopically placed intrahepatic portosystemic stents have recently been used with increasing frequency. OBJECTIVE: To compare sclerotherapy with transjugular intrahepatic portosystemic shunt (TIPS) in patients with bleeding from esophageal varices. DESIGN: Randomized, controlled clinical trial. SETTING: Three teaching hospitals. PATIENTS: 49 adults hospitalized with acute variceal hemorrhage from November 1991 to December 1995: 25 assigned to sclerotherapy and 24 assigned to TIPS. INTERVENTION: Patients assigned to repeated sclerotherapy had the procedure weekly. In those assigned to TIPS, an expandable mesh stent was fluoroscopically placed between an intrahepatic portal vein and an adjacent hepatic vein. MEASUREMENTS: Pretreatment measures included demographic and laboratory data. Postrandomization data included index hospitalization survival, duration of follow-up, successful obliteration of varices, rebleeding from varices, number of variceal rebleeding events, total days of hospitalization for variceal bleeding, blood transfusion requirements after randomization, prevalence of encephalopathy, and total health care costs. RESULTS: Mean follow-up (+/-SE) was 567 +/- 104 days in the sclerotherapy group and 575 +/- 109 days in the TIPS group. Varices were obliterated more reliably by TIPS than by sclerotherapy (P < 0.001). Patients having TIPS were significantly less likely to rebleed from esophageal varices than patients receiving sclerotherapy (3 of 24 compared with 12 of 25; P = 0.012). No other follow-up measures differed significantly between groups. A trend toward improved survival, which was not statistically significant, was noted in the TIPS group (hazard ratio, 0.53 [95% CI, 0.18 to 1.5]). CONCLUSIONS: In obliterating varices and reducing rebleeding events from esophageal varies, TIPS was more effective than sclerotherapy. However, TIPS did not decrease morbidity after randomization or improve health care costs. It seemed to produce better survival, but the increase in survival was not statistically significant.

Gastrointestinal manifestations of AIDS.

As the AIDS epidemic continues to grow, it becomes increasingly important that physicians are aware of the gastrointestinal and abdominal diseases specific to this group of patients. Most AIDS patients exhibit gastrointestinal symptoms at some time during the course of their disease. Clinical AIDS is often determined by identifying an opportunistic infection or neoplasm of the gastrointestinal tract. Radiology often plays a key role in helping to determine the diagnosis as well as in directing the management.

Infectious esophagitis.

Infectious esophagitis is most often seen in patients with impaired host resistance. It has become a particular problem in the growing AIDS population. The three most commonly encountered opportunistic infections of the esophagus are Candida albicans, herpes simplex virus, and cytomegalovirus. Candida is the single leading cause of infectious esophagitis. Tuberculous and bacterial esophagitis and other unusual fungal infections of the esophagus are uncommon.