Renal artery occlusion model in dogs for the evaluation of thrombolytic agents

The purpose of this study was to develop a model of renal artery occlusion and to investigate the effects of various thrombolytic agents on an acute occlusion of the renal artery with respect to ischemic tolerance of renal parenchyma. In order to do this, a thrombosis model in dogs (n = 36) was established and a total of 72 dorsal renal arteries occluded using autologous clot material. For the in vitro preparing of a clot, autologous blood (20 mL) was withdrawn and 100 U thrombin immediately added. Then 1 mL of the clot material was injected into the dorsal branch of the exposed renal artery. The dogs were divided into 8 groups (2 control groups, 6 therapy groups with local and systemic thrombolytic therapy). Thrombolysis was performed using urokinase, single-chain urokinase, and recombinant tissue-plasminogen activator. In all cases the clot preparation technique allowed complete and stable occlusion of the renal arteries. Local and systemic application of the thrombolytic agents, however, resulted in complete recanalization of the clot material in all study groups. Recombinant tissue-plasminogen activator turned out to be the most effective agent in terms of recanalization time. The technique described allowed effective and reproducible artery occlusion for in vivo experimental work to study comparatively thrombolytic agents with respect to fibrin specificity, lytic efficacy, and side effects.

Late occurrence of cysts in autosomal dominant medullary cystic kidney disease

Medullary cystic kidney disease (MCD) is characterized by multiple renal cysts at the corticomedullary boundary area, by autosomal dominant inheritance, and by onset of chronic renal failure in the third decade of life. We report on a family with three affected individuals of both sexes in two generations presenting with end-stage renal failure at age 22-31 years. Primarily diagnoses considered included unclassified hereditary nephropathy and autosomal dominant polycystic kidney disease. Careful evaluation of all findings, initiated after investigation of renal morphology with CT, revealed features characteristic for MCD and led to the final diagnosis of MCD. We conclude that MCD is an important differential diagnosis for polycystic kidney disease in young adults with end-stage renal failure. Establishing the correct diagnosis has considerable impact for genetic counselling.

[Functional tricuspid atresia in a newborn infant with cardiac rhabdomyoma]

Cardiac rhabdomyomas are benign tumours closely associated with tuberous sclerosis. We report on a neonate with a cardiac rhabdomyoma, which simulated tricuspid atresia with duct-depending pulmonary perfusion due to almost complete obliteration of right ventricular cavum. Under infusion of prostaglandin E1 the newborn stabilized and was successfully operated on the 3rd day of life. We conclude that successful tumour resection is possible in neonates with cardiac rhabdomyomas causing relevant hemodynamic obstruction.

[Interventional occlusion of systemicopulmonary collateral arteries using metal spirals]

Major systemicopulmonary collateral arteries (spca) frequently contribute to collateral lung perfusion in patients with pulmonary atresia and ventricular septal defect or in children with tetralogy of Fallot. Since the surgical access to these vessels is difficult, corrective surgery may become impossible. We report our experience with interventional occlusion of spca in 10 patients. In these patients (age range 13 months-19.5 years) selective injections demonstrated a total of 27 spca. Sixteen of these were coil-occluded by interventional cardiac catheterization. Total occlusion was achieved in 15 cases, in one case we found a small residual shunt. Occlusion was performed using platinum coils (2 cases), Gianturco coils (11 cases) and detachable steel coils (4 cases, including 1 with prior incomplete occlusion by Gianturco coils). 4 patients required 2 interventional cardiac catheterizations. Complications occurred only in procedures that were performed with conventional coils (peripheral pulmonary embolizations of platinum coils in 2 patients, dislocation of the delivery catheter with a partially extruded coil to the descending aorta in 1 patient). Operative ligation had to be performed in 6 spca, since those vessels were not suitable for interventional occlusion. The remaining 5 spca were left unoccluded, since they were of minor hemodynamic relevance due to a subsequent decrease in size. At the end of the follow-up period corrective surgery had been completed in 8 of our 10 patients. In the remaining 2 patients corrective surgery is planned in the near future. According to our experience interventional occlusion of spca is a major improvement in the management of a selected cohort of patients with pulmonary atresia and ventricular septal defect or tetralogy of Fallot. The introduction of detachable steel coils facilitates the embolization of those vessels.

Comparative diagnostic accuracy of magnetic resonance imaging and immunoscintigraphy for detection of bone marrow involvement in patients with malignant lymphoma

PURPOSE

To compare the diagnostic accuracy of magnetic resonance imaging (MRI) and immunoscintigraphy (IS) for detection of bone marrow infiltration in malignant lymphoma.

PATIENTS AND METHODS

In 32 patients with Hodgkin's disease (HD) or non-Hodgkin's lymphoma (NHL), MRI of the axial skeleton and whole-body IS using technetium-99m (99mTc)-labeled monoclonal antibodies were reviewed and compared with iliac crest biopsies. Criterion for marrow infiltration was a positive biopsy or concordant positive results of MRI and IS.

RESULTS

In 16 patients (50%), MRI, IS, and iliac crest biopsies were negative for marrow infiltration. Iliac crest biopsy showed infiltration in only four patients (13%). Infiltration was missed in two of 32 patients with IS and in one patient with MRI. In one additional patient, MRI was false-positive because of pelvic hematopoietic hyperplasia. A subset of nine patients (28%) with negative biopsies had bone marrow involvement according to MRI and IS with identical location and pattern of infiltration. In eight of these nine patients, diagnostic imaging indicated marrow involvement only in noncrest marrow. Subsequent biopsy confirmed infiltration in five patients. The clinical course suggested true-positive imaging results in the remaining four patients. Two patients (6%) remained equivocal. Overall concordance of MRI and IS for marrow infiltration was 88% (28 of 32 patients).

CONCLUSION

Diagnostic imaging is essential for optimal staging in malignant lymphoma, as blind biopsies appear to have low sensitivity for bone marrow infiltration because of frequent involvement in noncrest marrow. both imaging modalities show a high rate of detection of bone marrow infiltration.

Two-center German experience with aortic endografting

PURPOSE

To report the results of a two-center study of endovascular abdominal aortic aneurysm (AAA) exclusion using a polyester-covered nitinol stent-graft.

METHODS

Candidates were evaluated with arteriography and computed tomography. Criteria for endovascular therapy were a proximal aortic neck > 10 mm in length and < 25 mm in diameter, no bilateral internal iliac artery involvement in the aneurysm, no markedly tortuous common iliac arteries (CIAs) or CIAs < 7 mm in diameter, and no superior mesenteric artery occlusive disease. Patients were treated with the Mialhe Stentor and Vanguard stent-grafts in either tube or bifurcated versions.

RESULTS

Between August 1994 and November 1996, 149 patients (mean age 67 years, range 49 to 90) were admitted to the study. Overall primary technical success (aneurysm exclusion without endoleak) was 87% (130 patients): 78% (7 patients) for tube grafts and 88% (123 patients) for bifurcated endografts. The rate of local, remote, or systemic complications was 10.8%, with a 30-day mortality rate of 0.7%. During an average 13.5-month follow-up, there were no late deaths. Four of 20 endoleaks sealed spontaneously, 14 were treated with endoluminal techniques, and 2 remain untreated by patient request. Three graft limb thromboses occurred; one was treated surgically, one with lytic therapy, and one was untreated. Secondary patency was 96%.

CONCLUSIONS

Endoluminal repair of infrarenal AAAs using straight or bifurcated grafts is a feasible alternative to conventional surgical repair. Longer follow-up and more experience with refined endograft models will elucidate the durability of this endovascular approach to treating AAAs.

Treatment of ostial renal-artery stenoses with vascular endoprostheses after unsuccessful balloon angioplasty

BACKGROUND

Percutaneous transluminal renal angioplasty is a safe and effective treatment for nonostial stenoses of the renal arteries, but it has proved to be disappointing for ostial stenoses. Therefore, we prospectively studied the use of intravascular stents for the treatment of critical ostial stenoses after unsuccessful balloon angioplasty.

METHODS

Stainless-steel endoprostheses were placed across 74 renal-artery stenoses located within 5 mm of the aortic lumen in 68 patients with hypertension. Twenty patients had mild or severe renal dysfunction. The indications for stent placement were elastic recoil (63 arteries) or dissection (1 artery) of the vessel after angioplasty, or restenosis after initially successful balloon angioplasty (10 arteries). Patients were followed for a mean of 27 months with measurements of blood pressure and serum creatinine, duplex sonography, and intraarterial angiography.

RESULTS

Initial technical success was achieved in all patients. Minor complications (local hematomas) occurred in only three patients; there were no major complications. Eighty-four percent of the patients were free of primary occlusion 60 months after the procedure. Restenosis of more than 50 percent of the vessel diameter occurred in 8 of 74 arteries (11 percent). Reintervention resulted in a secondary patency rate of 92 percent. Long-term normalization of blood pressure was achieved in 11 patients (16 percent). Serum creatinine levels did not change significantly after successful stent implantation in patients with previously impaired renal function.

CONCLUSIONS

Accurate placement of renal-artery stents is technically feasible without major complications. The favorable early and long-term results suggest that primary stent placement is an effective treatment for renal-artery stenosis involving the ostium.

Endoluminal stent-grafts for infrarenal abdominal aortic aneurysms

BACKGROUND

The treatment of aortic aneurysms with endovascular stents or stent-graft prostheses is receiving increasing attention as an alternative to major abdominal surgery. To define the clinical value of this technique, we prospectively studied the use of stent-graft endoprostheses made of nitinol and covered with polyester fabric for the treatment of infrarenal abdominal aortic aneurysms.

METHODS

We treated a total of 154 patients at three academic hospitals. Twenty-one patients with aortic aneurysms not involving the aortic bifurcation received straight stent-grafts, and 133 patients with aortic aneurysms involving the bifurcation and the common iliac arteries received bifurcated stent-grafts. After a unilateral surgical arteriotomy, the endoprostheses were advanced through the femoral arteries and placed under fluoroscopic guidance. Computed tomography and intraarterial angiography were performed during an average follow-up of 12.5 months.

RESULTS

The primary success rate, defined as complete exclusion of the abdominal aortic aneurysm from the circulation, was 86 percent in the group receiving straight grafts and 87 percent in the group receiving bifurcated grafts. In three patients the procedure had to be converted to an open surgical operation. Minor (n=13) or major (n=3) complications associated with the procedure (including 1 death) occurred in 10 percent of the patients. All patients had a postimplantation syndrome, with leukocytosis and elevated C-reactive protein levels.

CONCLUSIONS

Our results suggest that endovascular treatment of infrarenal abdominal aortic aneurysms is technically feasible and can effectively exclude abdominal aortic aneurysms from the circulation. With further refinement, endoluminal repair may emerge as an interventional strategy to treat infrarenal aortic aneurysms, especially in patients at high surgical risk.

Magnetic resonance imaging (MRI) for detection of active sacroiliitis--a prospective study comparing conventional radiography, scintigraphy, and contrast enhanced MRI

OBJECTIVE

Sacroiliitis is often difficult to diagnose in the absence of radiographic alterations. For the diagnosis of active sacroiliitis, plain radiography, scintigraphy, and contrast enhanced magnetic resonance imaging (MRI) were evaluated in a prospective study.

METHODS

In 44 consecutive patients with complete clinical and laboratory evaluation, plain radiographs, quantitative sacroiliac (SI) scintigraphy, and MRI were performed to evaluate the contribution of these imaging techniques to the diagnosis of active sacroiliitis. Scintiscanning and MRI were done in 20 control subjects to define the normal range of imaging findings. We determined the sensitivity and specificity for each imaging method using a reference standard based on clinical symptoms of inflammatory low back pain with or without laboratory signs, and on clinical and radiographic followup during 1.5-2.5 years to confirm diagnosis.

RESULTS

MRI was most sensitive (95%) and superior to quantitative SI scintigraphy (48%) or conventional radiography (19%) for the detection and confirmation of active sacroiliitis. For the assessment of inflammatory signs, MRI had higher specificity (100%) than scintigraphy (97%) or plain radiography (47%). At repeat MRI after 2-30 months, there was persistent pathologic signal intensity in the subchondral bone area despite clinically successful antiinflammatory drug therapy.

CONCLUSION

For the assessment of active changes in the synovial portion and the subchondral bone marrow, contrast enhanced MRI is superior to quantitative SI scintigraphy or conventional radiography. MRI picks up an additional 75% of early cases not diagnosed by plain radiography. Scintigraphy is only of limited value. Persistent pathologic signal intensity in the subchondral bone marrow seems to be closely associated with previous inflammatory episodes, thus limiting specificity of MRI for active sacroiliitis. Based on our findings we suggest an algorithm for the evaluation of patients with suspected active sacroiliitis.

[Diagnosis of hepatocellular carcinoma]

Hepatocellular carcinoma (HCC) is a frequent complication of chronic liver disease. The major causes of chronic liver diseases are hepatitis B virus (HBV) or hepatitis C virus (HCV) infection, as well as chronic alcohol misuse. The clinical presentations of HCC patients are unspecific, with signs and symptoms of chronic liver disease. Early diagnosis of HCC in an asymptomatic and potentially curable stage is of highest priority. The present strategy for the detection of early HCC in patients with chronic liver disease is 6-monthly determination of alpha-fetoprotein (AFP) and ultrasound study of the liver. If these are abnormal, further diagnostic steps include computer tomography, magnetic resonance tomography, lipiodol-angiography and histopathology. By this sequential diagnostic strategy it should be possible to identify HCC in patients with chronic liver disease at an early and potentially curable stage.

[Therapy of hepatocellular carcinoma]

The therapeutic modalities in patients with hepatocellular carcinoma (HCC) depend on the number, size and location of the lesions as well as the stage of the underlying liver disease and the physical condition of the patient. In patients with small and solitary lesions, resection, liver transplantation and in some cases percutaneous ethanol injection (PEI) can be curative. In more advanced stages of the disease with larger or multiple lesions, PEI and/or transarterial chemotherapy with or without embolization (TACE or TAC) can slow the progression of the disease. In disseminated disease, a radiotherapeutic approach can be taken in selected cases. The therapeutic strategy in patients with HCCs should be individualized, frequently involving a combination of therapeutic modalities. In contrast to the earlier dismal prognosis, for most HCC patients there is today a therapeutic strategy that results in prolongation of life and in some cases even cure.

Diagnosis of renovascular disease by intra- and extrarenal Doppler scanning

The purpose of this prospective, angiographically controlled study was to determine the diagnostic value of color Doppler sonography with two differing approaches of scanning in patients with clinical clues for renal artery stenosis (RAS). In 135 hypertensive patients peak systolic velocity in the main renal arteries and the resistive index (RI) of the intrarenal arteries were measured. The RI side-to-side-difference (delta RI) greater than 0.05 or peak systolic velocity greater than 2 m/s were used to discriminate normal from stenotic renal arteries, defined as angiographically confirmed RAS > 50%. In 88 of 135 patients 107 RAS were demonstrated by selective arteriography. Five renal artery occlusions occurred, which were all diagnosed by color Doppler sonography. Seventy-six RAS were detected by increased peak systolic velocity, and an additional 19 stenoses were identified by delta RI. The combined analysis of peak systolic velocity and delta RI resulted in a sensitivity of 89% and specificity of 92%. The positive predictive value was 92% and the negative predictive value was 88%. Our data suggest that only the combination of intra- and extrarenal scanning with color Doppler sonography represents an effective screening method for significant renal artery stenosis in hypertensive patients.

[Hemosuccus pancreaticus--a rare cause of upper gastrointestinal bleeding. Successful treatment in two cases by radiologic-interventional embolization of the splenic artery]

HISTORY AND CLINICAL FINDINGS

Two patients were admitted to hospital for diagnosis of recurrent upper gastrointestinal bleeding. Both had chronic pancreatitis with alcohol abuse. Their general condition was satisfactory. Physical examination showed no diagnostic abnormalities other than mild epigastric pain on pressure in one patient.

INVESTIGATIONS

In case 1 angiography revealed pseudoaneurysm of the splenic artery as a complication of chronic pancreatitis to be the cause of the bleeding. In case 2 sonography demonstrated multiple pancreatic pseudocysts after recurrent pancreatitis. Duplex sonography revealed one of the cyst to be a partly thrombosed pseudoaneurysm of the splenic artery and the source of the bleeding.

TREATMENT AND COURSE

In both cases a fistula between splenic artery and pancreatic duct having been shown to be the source of the bleeding, transcatheter embolisation of the splenic artery with platinum coils was successfully undertaken. Both patients remained symptom-free 4 and 10 months later.

CONCLUSION

Although haemosuccus pancreaticus is a rare cause of upper gastrointestinal bleeding, given certain features in the patient's history and the clinical findings, it should be included in the differential diagnosis.

Allelopathic interactions involving phenolic acids

A major concern regarding allelopathic interactions involving phenolic acids in no-till systems pertains to the fact that concentrations of individual phenolic acids recoverable from field soils are well below levels required for inhibition of germination and seedling growth in laboratory bioassays. Field soils contain a variety of phenolic acids as well as other toxic and nontoxic organic compounds that are available to interact with seeds and roots; whereas in laboratory bioassays, with few exceptions, single phenolic acids have been tested. Studies of mixtures of phenolic acids and other toxic (e.g., methionine) and nontoxic (e.g., glucose) organic compounds in laboratory bioassays indicate that the action of a single phenolic acid is not representative of the actions of such mixtures. Specifically, as the number of phenolic acids added to soil increased, concentrations of the individual phenolic acids required to bring about a growth inhibition declined. The addition of other organic compounds (e.g., glucose, methionine) to the soil also reduced the concentration of a phenolic acid (e.g., p-coumaric acid) required for growth inhibition. These results support the hypothesis that in the field mixtures of phenolic acids and other organic compounds can cause inhibitory effects even though the concentrations of individual compounds are well below their inhibitory levels.

[Endoluminal therapy of infrarenal abdominal aortic aneurysms: a new interventional technique]

PURPOSE

With a series of 31 transluminal stent-graft procedures, we assessed the feasibility and clinical effectiveness of a new stent-graft for the treatment of infrarenal abdominal aortic aneurysms (AAAs).

METHODS

We treated the patients (male; mean age 71 years) with straight or bifurcated nitinol stents covered with woven dacron graft material for infrarenal eccentric saccular AAA (n = 4) or AAA involving the bifurcation and the common iliac arteries (n = 27). The 18-F delivery system was advanced via a surgical arteriotomy and the stent-graft was placed under fluoroscopic control. Follow-up period ranged from 8 days to 9 months.

RESULTS

The implantation of the stent-grafts was technically successful in 30/31 cases. Procedure-related complications were acute hepatic failure due to gastric bleeding in a patient with liver cirrhosis, graft occlusion due to emboli originating from the left atrium (n = 1), macro-embolisation (n = 3), local haematoma (n = 1) and av-fistula (n = 1) requiring surgery. A post-implantation syndrome with leukocytosis and elevated C-reactive protein was observed in all patients.

CONCLUSIONS

Endoluminal repair of infrarenal AAA with use of dacron covered nitinol stent-grafts is feasible, safe and clinically effective. However, careful long-term evaluation is necessary.

[Initial clinical experiences with endovascular stent-grafts for treatment of infrarenal abdominal aortic aneurysm]

With a series of 34 transluminal stent-graft procedures, we assessed the feasibility and clinical effectiveness of a new stent-graft for the treatment of infrarenal abdominal aortic aneurysms (AAAs). We treated 34 male patients (mean age 71 years) with straight of bifurcated nitinol stents covered with woven Dacron graft material for infrarenal excentric saccular AAA (n = 3) or AAA involving the bifurcation and the common iliac arteries (n = 31). The 18-F delivery system was advanced via a surgical arteriotomy and the stent-graft was placed under fluoroscopic control. Follow-up period ranged from 8 days to 13 months. The implantation of the stent-grafts was technically successful with exclusion of AAA in 31/34 cases (91%). In 2 patients, there was a persisting leak at the distal end of the endoprosthesis after treatment; in another, marked coiling of the external iliac artery impeded the delivery system to be advanced and consecutive rupture resulted in conversion to surgical repair. Other procedure-related complications were acute hepatic failure due to gastric bleeding in a patient with liver cirrhosis, graft occlusion due to emboli originating from the left atrium (n = 1), local hematoma (n = 1), and AV-fistula (n = 1) requiring surgery. A post-implantation syndrome with leucocytosis and elevated C-reactive protein was observed in all patients. Endoluminal repair of infrarenal AAA with use of Dacron covered nitinol stent-grafts is feasible, safe and clinically effective. However, careful long-term evaluation is necessary before it will become clinical practice.

Abdominal aortic aneurysms: preliminary technical and clinical results with transfemoral placement of endovascular self-expanding stent-grafts

PURPOSE

To evaluate treatment of infrarenal abdominal aortic aneurysm (AAA) with a new endoluminal stent-graft.

MATERIALS AND METHODS

In 26 male patients, straight or bifurcated nitinol stents covered with woven Dacron graft material were implanted to treat eccentric saccular AAA (n = 3) or AAA involving the bifurcation and common iliac arteries (n = 23), with follow-up from 8 days to 8 1/2 months.

RESULTS

Implantation was technically successful in all but one of the 26 (96%) patients (leak of the stent-graft for more than 3 months necessitated implantation of an additional covered stent). In seven of the 26 patients, minor residual perfusion persisted immediately after implantation, but complete thrombosis occurred within 7 days. Five procedure-related complications occurred: distal embolization (n = 2); local hematoma, which necessitated surgery (n = 1); acute hepatic failure due to gastric bleeding, in a patient with liver cirrhosis (n = 1); and stent-graft occlusion due to emboli originating from the left atrium (n = 1).

CONCLUSION

Exclusion of AAA from circulation was feasible, safe, and clinically effective with the new stent-graft.

[Vascular stents and development of endoluminal therapy of aortic aneurysm]

Intravascular stents have played an important role in improving early and long-term patency in the treatment of arterial occlusive disease, particularly in the iliac arteries after failed balloon angioplasty. The development of covered stents opened a new dimension for non-operative therapy of aneurysmal disease. Transluminally placed stent-grafts represent a blending of technologies with use of intravascular stents and prosthetic vascular grafts. Stent-graft combinations were first envisioned by Dotter in 1969 as devices that would ultimately be useful to treat aneurysms, pseudoaneurysms and arterio-venous fistulas. Animal studies of endovascular stented grafts demonstrated the potential feasibility of these devices to treat arterial lesions. Parodi et al. first implanted stent-grafts in patients with abdominal aortic aneurysms and demonstrated its clinical feasibility. Newly developed stent-grafts allowed to treat successfully a limited number of patients with AAA. Although much has been reported about the healing properties of prosthetic grafts in extraluminal locations, there are only little data concerning the arterial response to a prosthetic graft placed within the lumen or anchored into the wall of a human vessel. Therefore, long-term evaluation of these new devices will be crucial.

Budd-Chiari syndrome: technical, hemodynamic, and clinical results of treatment with transjugular intrahepatic portosystemic shunt

PURPOSE

To evaluate use of the transjugular intrahepatic portosystemic shunt (TIPS) as a nonsurgical approach for the management of Budd-Chiari syndrome (BCS).

MATERIALS AND METHODS

Twelve patients with fulminant (n = 2), subacute (n = 5), or chronic (n = 5) BCS underwent TIPS placement. Hepatic venous obstruction was demonstrated at computed tomography and color duplex sonography. BCS was confirmed histologically in all patients. Hemodynamic parameters and clinical characteristics were assessed.

RESULTS

TIPS creation was successful in all patients. Treatment reduced the portal venous pressure gradient by 75% and resulted in a mean shunt flow of 2,300 mL/min +/- 650 (standard deviation). No serious procedure-related complications were observed. The two patients with fulminant BCS died of septicemia or progressive liver failure despite intervention. The other 10 patients showed clinical improvement with reduction or disappearance of ascites. During follow-up, shunt dysfunction occurred in five of 10 patients with recurrence of ascites requiring repeat intervention.

CONCLUSION

TIPS placement is safe and effective in patients with portal hypertension caused by subacute or chronic BCS.