Use of Doppler ultrasonography to predict the outcome of therapy for renal-artery stenosis

BACKGROUND

Prospectively identifying patients whose renal function or blood pressure will improve after the correction of renal-artery stenosis has not been possible. We evaluated whether a high level of resistance to flow in the segmental arteries of both kidneys (indicated by resistance-index values of at least 80) can be used prospectively to select appropriate patients for treatment.

METHODS

We evaluated 5950 patients with hypertension for renal-artery stenosis using color Doppler ultrasonography, and we measured the resistance index ([1 - end-diastolic velocity divided by maximal systolic velocity] x 100). Among 138 patients who had unilateral or bilateral renal-artery stenosis of more than 50 percent of the luminal diameter and who underwent renal angioplasty or surgery, the procedure was technically successful in 131 (95 percent). Creatinine clearance and 24-hour ambulatory blood pressure were measured before renal-artery stenosis was corrected; 3, 6, and 12 months after the procedure; and yearly thereafter. The mean (+/-SD) duration of follow-up was 32+/-21 months.

RESULTS

Among the 35 patients (27 percent) who had resistance-index values of at least 80 before revascularization, the mean arterial pressure did not decrease by 10 mm Hg or more after revascularization in 34 (97 percent). Renal function declined (defined by a decrease in the creatinine clearance; of at least 10 percent) in 28 (80 percent); 16 (46 percent) became dependent on dialysis and 10 (29 percent) died during follow-up. Among the 96 patients (73 percent) with a resistance-index value of less than 80, the mean arterial pressure decreased by at least 10 percent in all but 6 patients (6 percent) after revascularization; renal function worsened in only 3 (3 percent), all of whom became dependent on dialysis; and 3 (3 percent) died (P<0.001 for the comparison with patients with a resistance-index value of at least 80).

CONCLUSIONS

A renal resistance-index value of at least 80 reliably identifies patients with renal-artery stenosis in whom angioplasty or surgery will not improve renal function, blood pressure, or kidney survival.

Renal arterial stenoses: spiral CT angiography

PURPOSE

To evaluate the role of spiral computed tomography (CT) in diagnosis of renal arterial stenoses.

MATERIALS AND METHODS

In 22 patients with suspected renovascular hypertension, spiral CT angiography of the renal arteries was compared with arterial digital subtraction angiography (DSA). For each patient, the peak transit time t (from intravenous injection to maximum enhancement of the abdominal aorta) was determined with a bolus injection of 15 mL of contrast medium. Spiral scanning started at the level of the superior mesenteric artery with a delay of t + 5 seconds after the start of injection of 100-150 mL of contrast medium.

RESULTS

Spiral CT angiography demonstrated multiple renal arteries in five patients. A renal artery stenosis or occlusion was found in 15 of 22 patients (22 of 54 arteries). All findings were confirmed with arterial DSA. Vessel contrast on spiral CT scans was good to excellent in 19 of 22 patients. For diagnosis, axial-section and multiplanar reformatted images were superior to three-dimensional surface reconstructions and maximum-intensity projections.

CONCLUSION

Spiral CT angiography is a promising screening method for renal artery stenosis.

Risk of cancer incidence before the age of 15 years after exposure to ionising radiation from computed tomography: results from a German cohort study

The aim of this cohort study was to assess the risk of developing cancer, specifically leukaemia, tumours of the central nervous system and lymphoma, before the age of 15 years in children previously exposed to computed tomography (CT) in Germany. Data for children with at least one CT between 1980 and 2010 were abstracted from 20 hospitals. Cancer cases occurring between 1980 and 2010 were identified by stochastic linkage with the German Childhood Cancer Registry (GCCR). For all cases and a sample of non-cases, radiology reports were reviewed to assess the underlying medical conditions at time of the CT. Cases were only included if diagnosis occurred at least 2 years after the first CT and no signs of cancer were recorded in the radiology reports. Standardised incidence ratios (SIR) using incidence rates from the general population were estimated. The cohort included information on 71,073 CT examinations in 44,584 children contributing 161,407 person-years at risk with 46 cases initially identified through linkage with the GCCR. Seven cases had to be excluded due to signs possibly suggestive of cancer at the time of first CT. Overall, more cancer cases were observed (O) than expected (E), but this was mainly driven by unexpected and possibly biased results for lymphomas. For leukaemia, the SIR (SIR = O/E) was 1.72 (95 % CI 0.89-3.01, O = 12), and for CNS tumours, the SIR was 1.35 (95 % CI 0.54-2.78, O = 7). Despite careful examination of the medical information, confounding by indication or reverse causation cannot be ruled out completely and may explain parts of the excess. Furthermore, the CT exposure may have been underestimated as only data from the participating clinics were available. This should be taken into account when interpreting risk estimates.

Arterial chemoembolization before liver transplantation in patients with hepatocellular carcinoma: marked tumor necrosis, but no survival benefit?

BACKGROUND/AIMS

Hepatic artery chemoembolization was introduced in the treatment of patients with unresectable hepatocellular carcinoma waiting for liver transplantation. The rationale for this preoperative treatment was to control tumor growth during the waiting period and to improve long-term survival. This study aimed to investigate whether preoperative chemoembolization not only induces marked tumor necrosis but also has a survival benefit.

METHODS

In this study 21 patients with hepatocellular carcinoma who underwent pretransplant chemoembolization (group I) were compared with 21 historical control patients (group II) without preoperative chemoembolization in a case-control study. The number of pretransplant chemoembolizations in each patient in group I varied between 1 and 5 with a mean of 2.44+/-1.15. In addition, six patients of this group received preoperative systemic chemotherapy.

RESULTS

Overall, there were no differences in survival between the groups with and without pretransplant chemoembolization at 1 year (60.8% vs 61.5%) and at 3 years (48.4% vs 53.9%). In group I, three patients developed unexplained severe pneumonia, leading to death very early after liver transplantation. Marked tumor necrosis (>50%) was found in 14 cases in group I. In 6 out of these 14 patients, total tumor necrosis was observed.

CONCLUSION

Although preoperative chemoembolization or chemotherapy induced marked tumor necrosis, these patients showed no benefit in survival compared to historical controls, and appeared to be at higher risk of developing immediate postoperative infective complications.

Current practice of temporary vena cava filter insertion: a multicenter registry

PURPOSE

To evaluate the current practice of temporary vena cava filter placement and its complications.

MATERIALS AND METHODS

A multicenter registry was conducted from May 1995 until May 1997 using a standardized questionnaire. One hundred eighty-eight patients were evaluated. Patient characteristics, filter indications, filter characteristics, and complications were registered.

RESULTS

Deep vein thrombosis was proven in 95.2% of the patients. Main filter indication was thrombolysis therapy (53.1%). Average filter time was 5.4 days. An Antheor filter was inserted in 56.4%, a Guenther filter in 26.6%, and a Prolyser filter in 17.%. Transfemoral filter implantation was slightly preferred (54.8%). Four patients died of pulmonary embolism (PE) during filter protection. Major filter problems were filter thrombosis (16%) and filter dislocation (4.8%). When thrombus was found in or at the filter before explantation, additional thrombolysis was performed in 16.7%, additional filter implantation in 10%, and thrombus aspiration in 6.7%; 4.8% of filters were replaced with permanent filters.

DISCUSSION

Temporary vena cava filters are placed to prevent PE in a defined patient population. Despite their presence, PEs still occur in a small percentage. Problems of filter thrombosis and dislocation have to be solved.

CONCLUSION

The results of this multicenter registry support the need for innovative filter design, as well as a randomized, prospective study.

Role of liver transplantation in the treatment of unresectable liver cancer

Resection remains the treatment of choice in liver cancer. In order to avoid liver transplantation in conventionally unresectable tumors ex-situ ("bench" procedure), in-situ and ante-situm resection technique should be preferred whenever feasible. Despite the deficiency of donor organs, a single center experience with 198 patients reveals that liver transplantation continues its role as a therapeutic option for selected patients. At present "favorable" indications for transplantation are International Union against Cancer (UICC) - stage II hepatocellular carcinoma as well as the subtype fibrolamellar carcinoma, uncommon tumors such as epitheloid hemangioendothelioma, hepatoblastoma, and liver metastases from neuroendocrine tumors. Due to unsatisfying results, intrahepatic bile duct-, stage III and IV hepatocellular carcinoma, hemangiosarcoma, and liver metastases from nonendocrine primaries should be excluded from liver transplantation alone. For these advanced tumors, especially in cases of extrahepatic involvement, a combination of liver transplantation and multivisceral resection has been proven feasible. However, a significant improvement in patient survival may only be expected only by currently investigated multimodality treatment protocols which will require further randomized studies.

Intravascular ultrasound-guided percutaneous fenestration of the intimal flap in the dissected aorta

BACKGROUND

Aortic dissection with branch obstruction is associated with high morbidity and mortality. Fenestration of the dissection flap to relieve distal vessel ischemia is at present largely performed surgically. The surgical mortality and morbidity are high, because most patients are poor candidates for anesthesia or surgery.

METHODS AND RESULTS

Nine percutaneous fenestrations (one with additional stenting of the infrarenal true aortic lumen) were performed under local anesthesia in seven patients with aortic dissection. The presenting symptoms were abdominal angina or claudication. By the transfemoral approach, the intimal flap was initially punctured with a needle-catheter combination through which a guidewire was placed across the dissection flap. The fenestration was carried out with a balloon catheter introduced over the guidewire. The procedure was performed under on-line guidance with intravascular ultrasound imaging. The procedure was performed successfully and without complications in all patients. After intervention, symptoms resolved in all seven patients.

CONCLUSIONS

Intravascular ultrasound-guided percutaneous fenestration of the intimal flap in symptomatic aortic dissections with distal vessel involvement is a technically feasible and safe procedure that can effectively relieve the patient's symptoms.

Minimally invasive diagnosis of renal artery stenosis by spiral computed tomography angiography

We prospectively compared in a blinded fashion spiral computed tomography angiography (CTA) with arteriography in 62 consecutive patients with suspected renal artery stenosis (RAS). For CTA 150 ml of contrast material were injected intravenously. Arteriography was performed by DSA technique with selective catheterization of renal arteries. Of the 157 visualized renal arteries 155 could be evaluated with DSA and a total of 157 with CTA. Sensitivity of CTA for RAS > or = 50% was 98% and the specificity was 94%. Comparison of the grade of stenosis as evaluated by DSA versus CTA showed: identical gradation in 59 arteries (DSA > or = 50%/CTA > or = 50%), underestimation by CTA in one artery (DSA 50 to 75%/CTA < 50%), and overestimation by CTA in six arteries (DSA < 50%/CTA 50 to 75%). Factors that may contribute to these differences include impaired renal function and possibly "underestimation" of ostial RAS by arteriography. One artery not evaluable by arteriography showed a 70% stenosis by CTA. CTA showed no major side effects. We conclude that CTA has the same accuracy for the diagnosis of RAS > or = 50% as arteriography. However, CTA is only minimally invasive, safe, and causes less discomfort to patients.

Clinical outcome of transfemoral embolisation in patients with arteriovenous malformations of the liver in hereditary haemorrhagic telangiectasia (Weber-Rendu-Osler disease)

BACKGROUND

Arteriovenous malformations of the liver in Osler's disease may present as high output cardiac failure. A few case reports suggested that treatment with arterial embolisation may have beneficial effects in such patients.

AIMS

To investigate the efficacy and safety of this treatment modality in a prospective pilot study.

PATIENTS AND METHODS

Four women and one man (aged 39-59 years) with the dominant hepatic manifestation of Osler's disease presented with symptoms of cardiac failure and elevated cardiac output. Arteriovenous malformations were treated in three to five sessions with arterial embolisation using coils. The outcome was analysed by measurement of cardiac output and scoring of clinical symptoms.

RESULTS

Embolisation was technically feasible in all patients and adequate occlusion of vascular malformations was achieved in four patients. After completion of therapy symptoms improved in four patients, while one patient suffered from abdominal pain due to cholangitis. One patient died seven months after the embolisation treatment from variceal bleeding. Mean cardiac output significantly decreased from 14.2 (range 12-17.3) l/min to 8 (range 5.9-10.6) l/min (p = 0.043). After a median follow up of 23 months (range 7-50 months), three of five patients had a long lasting improvement of clinical symptoms and cardiac function.

CONCLUSIONS

This first treatment series of patients with dominant hepatic involvement in Osler's disease indicates that arterial embolisation may prevent cardiac failure by significantly lowering cardiac output.

[Diagnosis of and therapy for hepatocellular carcinoma]

The interdisciplinary guidelines at the S3 level on the diagnosis of and therapy for hepatocellular carcinoma (HCC) constitute an evidence-and consensus-based instrument that is aimed at improving the diagnosis of and therapy for HCC since these are very challenging tasks. The purpose of the guidelines is to offer the patient (with suspected or confirmed HCC) adequate, scientifically based and up-to-date procedures in diagnosis, therapy and rehabilitation. This holds not only for locally limited or focally advanced disease but also for the existence of recurrences or distant metastases. Besides making a contribution to an appropriate health-care service, the guidelines should also provide the foundation for an individually adapted, high-quality therapy. The explanatory background texts should also enable non-specialist but responsible colleagues to give sound advice to their patients concerning specialist procedures, side effects and results. In the medium and long-term this should reduce the morbidity and mortality of patients with HCC and improve their quality of life.

First experience and technical aspects of isolated liver perfusion for extensive liver metastasis

BACKGROUND

New drugs and modalities for locoregional tumor treatment in recent years may offer new potential for isolated liver perfusion in patients with nonresectable liver tumors. The purpose of this study was to prove the feasibility of arterial isolated liver perfusion and to assess the tolerance of perfusion with high-dose tumor necrosis factor (TNF).

METHODS

Twelve patients with extensive liver metastases previously treated unsuccessfully with systemic chemotherapy underwent isolated hyperthermic liver perfusion using a heart-lung machine. High doses of mitomycin were administered in the first six and a combination of TNF and melphalan in the last six patients.

RESULTS

No operative death occurred and no direct postoperative liver failure was observed in any patient. In cases of variations of the arterial hepatic blood supply, the perfusion was done through the splenic artery or an angiography catheter. Histologic analysis of tumor biopsy specimens obtained on the first postoperative day revealed major tumor necrosis in 8 of 12 patients.

CONCLUSIONS

Isolated arterial perfusion of the liver is a complex surgical procedure that is feasible in patients with anatomic variations of the hepatic artery. The remarkable histologic response to perfusion in several pretreated patients, especially after application of high-dose TNF and melphalan, suggests that this modality is very effective in tumor killing.

Ureteric reconstruction

Although the ureter is functionally simply a tube to transport urine, ureteric surgery requires detailed anatomical knowledge and advanced surgical skills, because the ureter has a delicate blood supply. Therefore, the urological surgeon must have distinct strategies available to bridge ureteric defects of various sites and lengths. Furthermore, handling during and after surgery should be individualized to the patient's pre- and intraoperative situation. In this review, the indications for reconstruction of a specific ureteric defect, the required techniques and postoperative recommendations are discussed.

Chemoocclusion vs chemoperfusion for treatment of advanced hepatocellular carcinoma: a randomised trial

AIMS

Transarterial chemoembolization (TACE) can be associated with considerable toxicity and treatment-associated mortality. Transient transarterial chemoocclusion (TACO) using degradable starch microspheres (DSM) has been proposed as a potentially safer alternative while maintaining anti-tumour efficiency. In a randomised phase II trial TACO was compared to transarterial chemoperfusion without DSM (TACP).

METHODS

Seventy-four patients with advanced HCC were randomised to two treatment arms: (i) TACO (600-1200 mg DSM) and (ii) TACP. In both arms regional chemotherapy consisted of cisplatin (100 mg/m2) and doxorubicin (60 mg/m2). Both arms were corresponding in terms of age, gender, liver performance state, and tumour-stage. A maximum of six treatment cycles was applied in monthly intervals. Follow-up was performed in terms of tumour response, time to progression, survival and quality of life.

RESULTS

Tumour response rates did not differ significantly between the two treatment arms, however, there was a tendency towards higher response rates in the TACO arm (TACO vs TACP): partial response: 26 vs 9%, stable disease: 41 vs 55%, progressive disease: 33 vs 36%. Time to tumour progression (32 vs 27 weeks), and overall survival (60 vs 69 weeks) were not significantly different. Grade 4 adverse events were rare in both arms and treatment-associated mortality was not observed. In addition, there was no significant difference in terms of quality of life under therapy (EORTC).

CONCLUSION

TACO with DSM did not improve response or survival significantly compared to TACP in advanced non-resectable HCC.

Hereditary hemorrhagic telangiectasia: effective protocol for embolization of hepatic vascular malformations--experience in five patients

PURPOSE

To develop a hepatic artery embolization protocol and investigate its efficacy in a prospective study treating patients with hereditary hemorrhagic telangiectasia and predominant hepatic involvement.

MATERIALS AND METHODS

One man and four women with hereditary hemorrhagic telangiectasia presented with symptoms of high-output heart failure, abdominal angina, or severe portal hypertension. The hepatic arteries were embolized in stages in three to five sessions at 1- to 15-week intervals. After peripheral embolization with polyvinyl alcohol particles, proximal arteries were embolized with coils. Computed tomography and assessment of cardiac output were performed before and after therapy and at the end of follow-up (median, 25 months; range, 12-55 months).

RESULTS

After embolization, analgesics and antiemetics were necessary for a median of 5 and 2 days, respectively. Other than ischemic cholangitis (one patient), no complications were observed. The mean cardiac output decreased significantly (P < .05) from 14.2 L/min to 8.0 L/min. Symptoms of high-output heart failure, abdominal angina, and portal hypertension resolved in all patients. Seven months after embolization, one patient died of postoperative sepsis after an unsuccessful surgical attempt to create a portacaval shunt. Delayed recurrence of symptoms was not noted in the other patients.

CONCLUSION

In symptomatic patients with hereditary hemorrhagic telangiectasia and predominant hepatic involvement, embolization of the hepatic arteries in stages is well tolerated by the patients and results in good clinical improvement at midterm follow-up.

[Accuracy of CT angiography in the diagnosis of renal artery stenosis]

Spiral CT in the form of CT angiography (CTA) provides a new method for the investigation of the large vessels. 52 patients with suspected renovascular hypertension were examined by CTA and arterial DSA. The computer tomographic and angiographic findings in 124 renal arteries were compared. Sensitivity of CTA for demonstrating renal artery stenosis was 95%, and for relevant stenoses it actually reached 100%. Specificity was 92%. Positive/negative prediction value was 85% and 100%. CTA proved outstandingly good for demonstrating or excluding renal artery stenosis and was superior to other imaging methods in several respects. CTA requires high contrast values, optimal timing and careful evaluation. Amongst various forms of image reconstruction, interactive viewing of the primary axial images and multiplanar reconstruction in a cine mode are essential and MIP projections are valuable.

Role of the intra-arterial calcium stimulation test in the preoperative localization of insulinomas

The aim of this study was determination of the significance of the arterial stimulation test with venous sampling (ASVS) in the preoperative localization of insulinoma. Eleven patients with endogenous hyperinsulinism underwent preoperative transabdominal US, spiral computer tomography (spiral CT), MRI, endoscopic ultrasound (EUS) as well as angiography (DSA) combined with ASVS. The results were compared with intraoperative findings, intraoperative ultrasound (IOUS) and histopathology. There were no complications related to the ASVS test. In 11 patients the tumor could be localized with the various modalities as follows: US 1 of 11 (9%), MRI 3 of 10 (30%), spiral CT 4 of 11 (36%), EUS 5 of 10 (50%), DSA 8 of 11 (73%), and ASVS 10 of 11 (91%). In 2 patients the tumors were intraoperatively neither palpable nor detectable by IOUS, and consequently the intraoperative management was governed by information provided by DSA combined with the ASVS test. Ten patients had solitary benign insulinomas and 1 patient with multiple endocrine neoplasia I had two tumors adjacent to each other in the pancreatic tail. Arterial stimulation test with venous sampling was the most sensitive preoperative test for regionalizing the insulinoma in our set of patients. It can be performed safely in the course of a regular DSA examination and may affect intra-operative management in patients in whom the tumors are not detectable by palpation or IOUS.

Matched-pair analysis of conventional versus endoluminal AAA treatment outcomes during the initial phase of an aortic endografting program

PURPOSE

To investigate whether endovascular stent-grafts implanted during the early phase of an aortic endografting program have advantages over conventional surgical procedures for treatment of infrarenal aortic aneurysm (AAA).

METHODS

In the first months of an endografting program, 37 patients (36 men; mean age 67.9 +/- 7.1 years, range 55 to 86) underwent AAA repair with endovascular implantation of a Vanguard (n = 17) or Talent (n = 20) bifurcated stent-graft. Data collected during the perioperative period and in follow-up were compared retrospectively to a matched group of 37 elective surgical patients.

RESULTS

All endograft implantations were completed. Two type I and 6 type II endoleaks (21.6%) were seen postoperatively. Five type II sealed without intervention; 1 type I endoleak was corrected with an additional stent, but 1 type I and 1 type II endoleaks persisted despite attempts with coil embolization. Two (5.4%) endograft patients died during the perioperative period; however, this was not significantly different (p = 0.15) from the control group. In the mean follow-up of 12 +/- 6 months for both groups, 1 (2.7%) late conversion was necessary at 2 years for aneurysm expansion in an endograft patient with an unsealed type I endoleak.

CONCLUSIONS

In our learning curve experience with aortic endografting, postoperative morbidity and mortality were higher in endograft patients compared to conventionally treated controls. Only in the endograft group was reoperation required during follow-up. Careful monitoring with periodic imaging studies is mandatory after endoluminal AAA treatment.

Transarterial chemoembolization and percutaneous ethanol injection therapy in patients with hepatocellular carcinoma

Both transcatheter arterial chemoembolization (TACE) and percutaneous ethanol injection therapy (PEI) have proven their efficacy in patients with unresectable hepatocellular carcinoma (HCC): TACE mainly in large lesions or disseminated disease and PEI in solitary lesions smaller than 3 cm. Although severe complications have been observed with both methods, their incidence is low. In 1991, the combination therapy of initial TACE followed by multiple sessions of PEI was introduced, allowing the repeated percutaneous treatment of lesions larger than 4 cm. This approach has been shown to be more effective than TACE alone in lesions up to 8 cm in diameter. An increased incidence of serious side-effects compared to either method alone has not been reported so far.

Site-specific photobiotinylation of immunoglobulins, fragments and light chain dimers

Herein we report a new method to rapidly photoinsert biotin into a specific and highly conserved site on the Ig structure using a mild photochemical activation step. This site resides in the Fv fragment and involves invariant residues which provide base stacking interactions to the purine ring of ATP (Rajagopalan et al. (1996) Proc. Natl. Acad. Sci. USA 93, 6019-6024). Biotin was coupled to either the phosphate or the ribose of the 8-azidopurine nucleotide or nucleoside photoaffinity probe and shown to insert into the affinity site efficiently. Several monoclonal and polyclonal antibodies, as well as enzymatic and recombinant antibody fragments and light chain dimers were photoaffinity biotinylated and used in ELISA, FACS and Western blots. The selectivity of this site-specific biotinylation method also allows for biotinylation of antibodies in culture supernatants and immune sera without prior purification. Because the biotinylation takes place under physiological conditions and within a short time period, photobiotinylation would be the preferred method for antibodies which are easily damaged by classical non-site specific random biotinylation chemistry.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

[Hereditary hemorrhagic telangiectasia (Osler-Rendu-Weber disease) and its manifestation in the liver]

M. Osler (Hereditary Hemorrhagic Telangiectasia, HHT) is an autosomal dominant inherited disease, with various vascular malformations. The genetic cause of this disease lies in different defects of transmembrane proteins (endoglin, activin receptor like-kinase 1) that can be defined as components of the receptor complex for transforming growth factor beta (TGF beta). Vascular malformations include the gastrointestinal tract and especially the liver. The location of mutations encoding hepatic involvement of M. Osler still remains unknown. These vascular malformations may lead to different shunts in the liver and can result to different complications like cardiac-insufficiency, portal hypertension and hepatic encephalopathy in adulthood. Color Doppler sonography is the method of choice for screening patients with M. Osler--suspected of having hepatic involvement. As in rare events conservative treatment of complications of hepatic involvement fail, embolization of the hepatic artery as minimal invasive therapy, surgical ligation of the A. hepatica and liver transplantation are possible treatment options. As there are only limited experiences with these therapeutic procedures patients with liver involvement should be treated at a center, where all therapy options are available.

Recurrent angina pectoris in patients with internal mammary artery to coronary artery bypass: treatment with coil embolization of unligated side branches

PURPOSE

The purpose of the study was to evaluate the effect on the symptoms of transcatheter coil embolization of branches of the internal mammary artery.

MATERIALS AND METHODS

In five patients with coronary steal syndrome that was caused by preferential flow in large unligated side branches of the internal mammary artery, coil embolization of the side branches was performed with use of a coaxial microcatheter.

RESULTS

Anginal symptoms disappeared in three patients and were substantially reduced in one patient following the radiologic intervention. In the fifth patient, who had concomitant stenoses of other coronary vessels, only a moderate change in symptoms was noted. No complications occurred.

CONCLUSION

In patients with internal mammary artery to coronary artery bypass who experience recurrent angina pectoris caused by preferential flow in large, unligated side branches of the internal mammary artery, repeat surgery may be circumvented or simplified by transcatheter coil embolization, which can help treat the angina.

Endoluminal grafting of abdominal aortic aneurysms: experience with the Talent endoluminal stent graft

The aim of this study was to evaluate the Talent endoluminal stent graft (TESG) in treating abdominal aortic aneurysms (AAA). The TESG is a polyester-covered nitinol endograft (proximal diameters 20-38 mm and iliac limb diameters 8-22 mm). Twenty-two men were treated with the TESG via bilateral femoral arteriotomies. Pre-implantation, coil embolization of various vessels arising from the aneurysm was performed in 6 patients. Plain radiographs and spiral CT angiograms (CTA) were carried out at 7 days, 3, 6, and 12 months following TESG implantation or re-intervention. Median aortic and iliac diameters were 27 mm (range 20-34 mm) and 14 mm (range 10-19 mm). The corresponding graft diameters were 30 mm (range 24-38 mm) and 14 mm (range 12-20 mm). No patient was rejected purely on the basis of too large aortic or iliac diameters. Eight patients required custom-made grafts. Graft implantation was successful in all patients. There were no blood transfusions, distal embolic episodes, or conversions to open surgery. Re-intervention was necessary in 1 patient. Complications included one fatal myocardial infarction, one inguinal hematoma, and two superficial wound infections. The aneurysm thrombosed completely following implantation in 14 patients and at 3 or 6 months in 4 other patients. One patient with endoleak is awaiting his 3-month control and 2 patients show tiny endoleaks but reduction of aneurysm size. The mean aneurysm size decreased significantly from 58 +/- 10 to 53 +/- 13 mm (p < 0.0005). Due to the large sizes available and the option of custom-made grafts, the TESG helps widen the spectrum of patients who can be treated with endoluminal grafting. The treatment is associated with a significant reduction in aneurysm size.

Precise determination of aortic length in patients with aortic stent grafts: in vivo evaluation of a thinning algorithm applied to CT angiography data

The aim of this study was to develop a technique for precise determination of the aortic length using volumetric CT data for potential use prior to endovascular stent-graft placement. The study population consisted of 20 patients (38 measurements) with already performed endoluminal grafting. This allowed for in vivo evaluation of our technique. Its length according to the graft specifications served as a gold standard for our own measurements. The implemented graft length varied between 120 and 195 mm. Computed tomography angiography was performed with 3-mm slice collimation, 5-mm table feed and a reconstruction interval of 2 mm. Following semi-automatic segmentation of the aorta and its large side branches, the median centerline (skeleton) of the vessels was determined employing a modified three-dimensional thinning algorithm. The algorithm was validated by comparing the calculated length of the resulting skeleton with the specifications of the grafts. The calculated length was sufficiently precise despite the limiting reconstruction interval of 2 mm of our CT data which only permitted an assessment of stent length in 2-mm steps. The differences in the measured length and graft length were in the range between 0 and 8 mm (< 5%) with a mean fractional error of 2.46 +/- 2.37 mm. The use of an intelligent region growing algorithm capable of coping with variable arterial enhancement significantly reduced operator post-processing time. The average time necessary for segmentation was 7 min (range 3-10 min). Our algorithm provides a non-invasive method for objective and precise measurement of aortic length apparently even in tortuous vessels. It has the potential to replace angiography for aortic and iliac length measurements with calibrated catheters prior to endovascular intervention.

[Minimally invasive therapy options in aortic dissections]

Current day therapy for aortic dissection is aimed at the relief of branch vessel ischemia and the prevention of aortic rupture or aneurysm formation. Malperfusion complicating aortic dissection has historically been treated by surgery. Operations in patients with branch-vessel involvement may be technically difficult and the operative mortality is reported to be between 25% and 51%. This may rise to above 70% in patients with critical mesenteric or renal ischemia. Over the past decade, successful relief of such ischemia using the interventional radiological techniques of balloon fenestration, stent implantation and/or thrombolysis has been reported. In addition to being less invasive, this approach is associated with a lower mortality, ranging between 0% and 25%. Patency of the false lumen increases the probability of aortic rupture or aneurysm formation. Recent studies have reported successful closure of the proximal entry site with the help of stent grafts. The aim of the intervention is to initiate a thrombosis of the false lumen and thus stabilize the dissection. Based on a review of the literature and our own experience, we discuss the percutaneous management of branch vessel ischemia complicating aortic dissection as well as the role of stent graft implantation in patients with aortic dissection.