Biomedical subjects
Publications and source records attributed to K Ivancev.
We present a case of splenic artery aneurysm (SAA) treated with stent-grafts. This new method offers the benefit of preserving the blood flow through the splenic artery. This in turn allows for subsequent sequential embolization of the spleen when indicated, as in our patient with hypersplenism. This is the first reported case of stent-graft repair of SAA.
Persistent aneurysm perfusion represents failure of endovascular repair. The leak may occur around either end of the prosthesis or through a collateral route. Most cases can be treated by endovascular means. Stents can be rotated, the prosthesis can be lengthened at either end, and collateral pathways can be occluded, all without recourse to open repair. This report describes the management of persistent aneurysm perfusion in five patients from a total experience of 32 cases of endovascular aneurysm repair.
PURPOSE: To evaluate the midterm results of percutaneous transluminal angioplasty (PTA) and stent placement in stenotic and occluded mesentesic arteries in five consecutive patients with chronic mesenteric ischemia. METHODS: Five patients with 70%-100% obliterations of all mesenteric vessels resulting in chronic mesenteric ischemia (n = 4) and as a prophylactic measure prior to abdominal aortic aneurysm repair (n = 1) underwent PTA of celiac and/or superior mesenteric artery (SMA) stenoses (n = 2), primary stenting of ostial celiac occlusions (n = 2), and secondary stenting of a SMA occlusion (n = 1; recoil after initial PTA). All patients underwent duplex ultrasonography (US) (n = 3) and/or angiography (n = 5) during a median follow-up of 21 months (range 8-42 months). RESULTS: Clinical success was obtained in all five patients. Asymptomatic significant late restenoses (n = 3) were successfully treated with repeat PTA (n = 2) and stenting of an SMA occlusion (n = 1; celiac stent restenosis). Recurrent pain in one patient was interpreted as secondary to postsurgical abdominal adhesions. Two puncture-site complications occurred requiring local surgical treatment. CONCLUSIONS: Endovascular techniques may be attempted prior to surgery in cases of stenotic or short occlusive lesions in patients with chronic mesenteric ischemia. Surgery may still be preferred in patients with long occlusions and a low operative risk.
Percutaneous endovascular techniques were used to treat an arteriovenous fistula (AVF) associated with pancreatic transplantation. A pancreatic transplant superior mesenteric artery-to-superior mesenteric-vein AVF was successfully embolized while flow to the pancreas transplant was preserved. The embolization was aided by the use of Guglielmi detachable coils and a detachable balloon. No complications were encountered. At 23 months follow-up, the patient is doing well with no recurrence.
PURPOSE: To evaluate the results of primary stenting in aortic occlusive disease. METHODS: Thirty patients underwent primary stenting of focal concentric (n = 2) and complex aortic stenoses (n = 19), and aortic or aorto-iliac occlusions (n = 9). Sixteen patients underwent endovascular outflow procedures, three of whom also had distal open surgical reconstructions. Median follow-up was 16 months (range 1-60 months). RESULTS: Guidewire crossing of two aorto-biiliac occlusions failed, resulting in a 93% (28/30) technical success. Major complications included one access hematoma, one myocardial infarction, one death (recurrent thromboembolism) in a patient with widespread malignancy, and one fatal hemorrhage during thrombolysis of distal emboli from a recanalized occluded iliac artery. One patient did not improve his symptoms, resulting in a 1-month clinical success of 83% (25/30). Following restenting the 26 stented survivors changed their clinical limb status to +3 (n = 17) and +2 (n = 9). During follow-up one symptomatic aortic restenosis occurred and was successfully restented. CONCLUSIONS: Primary stenting of complex aortic stenoses and short occlusions is an attractive alternative to conventional surgery. Larger studies with longer follow-up and stratification of lesion morphology are warranted to define its role relative to balloon angioplasty. Stenting of aorto-biiliac occlusions is feasible but its role relative to bypass grafting remains to be defined.
Six patients with high-grade malignant esophageal obstruction were treated with silicone-coated metallic self-expanding esophageal stents (Z stents). Endoscopic placement of stents was well tolerated. All patients achieved excellent palliation, defined by a decrease of at least two dysphagia grades, which was sustained. Complications occurred during follow-up in four patients and included stent migration, silicone disruption with tumor ingrowth, food impaction, and perforation (discovered at autopsy) at the distal stent site. Three of the four complications were promptly treated by endoscopic or radiologic intervention. Recent modification in stent design and placement technique will hopefully reduce complications. The self-expanding stent has several theoretical advantages over the rigid plastic stent and Nd:YAG laser for palliation of obstructing esophageal malignancy.
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PURPOSE: To determine the long-term results of Gianturco-Rösch Z (GRZ) stent placement for the treatment of recurrent, benign biliary strictures in liver transplant recipients. MATERIALS AND METHODS: During a 5-year period, eight orthotopic liver transplant recipients underwent transhepatic placement of GRZ stents to treat 12 recurrent biliary strictures (six anastomotic, six intrahepatic). Prior treatment of 11 strictures with balloon dilation therapy had failed. Patients were followed up for 1-65 months. RESULTS: Stent placement was successful in all patients. Stent position remained stable in all but one patient. Three patients died (1, 25, and 28 months after stent placement), all with patent stents. Four patients required no further biliary intervention. Two of the other four patients needed intermittent biliary balloon dilation with removal of bile duct debris. The third patient had a stable, nonobstructing stenosis in the stent. The fourth passed his stents and needed no further intervention. CONCLUSION: GRZ stents are useful in patients who are refractory to repetitive balloon dilation of biliary strictures or who are poor surgical candidates.
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Twenty-three angiographies were performed in 20 rats with a totally arterialized liver. The arterialization was obtained by the construction of an end-to-side portacaval shunt (PCS) and an arteriovenous (AV) fistula between the left gastric artery and the portal stump. Microsurgical technique was necessary because of the small diameter of the AV fistula (0.5 mm). The angiographic examinations showed an AV fistula patency rate of 70% and a PCS rate of 100%. A successively increasing diameter of the fistula with dilation of the intrahepatic portal vessels was demonstrated in the rats with a patent arterioportal fistula. Tortuous and irregular vessels were also observed. All these signs suggest an overarterialization which developed despite the use of a very small AV fistula. None of the three rats examined histologically had cirrhosis of the liver. Further research is needed to attempt to avoid or minimize the deleterious effects of overarterialization of the portal tree, while utilizing the advantages of a dual liver blood supply in patients with decompressive PCS.
Two infants with total colonic aganglionosis (TCA) extending into the distal part of the ileum are described. Considerable diagnostic delay occurred with the correct diagnosis established first at 3 and 8 months, respectively. Radiologic findings compatible with TCA such as prolonged barium retention, reflux into ileum following barium enema, and foreshortening of colon were not clearly evident initially. Both patients demonstrated multiple acquired colon diverticula which increased both in number and size during the period of observation. These diverticula are probably a late manifestation of the spastic state of the anganglionic colon. Thus demonstration of diverticula supplies a strong evidence of TCA in infants with intestinal obstruction.
The effect on the renal parenchyma caused by rapid dilatation of a nephrostomy track to 24 F to 30 F was studied on 9 kidneys in 5 pigs. Angiography at different intervals up to 5 weeks was used in combination with histology. Moderate bleeding and short lacerations were observed around the puncture site in all kidneys. Complications included one transient pyelovenous reflux, one organized abscess following perforation of the upper pole, and two cases of hydronephrosis caused by abscess and inflammation. These infections were probably due to the prevailing sanitary conditions. No arteriovenous fistula formation was seen. Minimal scars were encountered after 4 to 5 weeks follow-up. Transparenchymal access to the pelvocaliceal system through percutaneously established large tracks seems to cause limited damage which resolves in minor scars provided perforations are avoided by an optimum technique and infections are prevented or treated appropriately.
Iodinated lipid emulsions have been shown to have great potential as site specific contrast media for the liver and spleen. Because of unacceptable adverse reactions none of these emulsions has been adopted for clinical use. In an attempt to find an explanation for these adverse reactions we tested three iodinated lipid emulsions, EOE-13, AG 60.99 and AG 66.18. The following models were used: Computed tomography (CT) of the rabbit liver, in vivo microscopy and electron microscopy of the rat liver. The emulsions contained particles of different sizes and were used in varying doses. We found that the larger the emulsion particles, the more likely they were to be taken up by the Kupffer cells and thereby the higher the opacification of the liver achieved at CT. We also observed changes in the microcirculation of the liver when the emulsions were given in doses required to secure satisfactory opacification of the liver at CT. The main changes were 1) a marked increase in the size of the Kupffer cells, and 2) damage to the sinusoidal endothelium, both contributing to sinusoidal congestion. These changes strongly suggest activation of the macrophages and this in turn probably results in the release of toxic mediators. We suspect that the adverse reactions observed in patients when using iodinated lipid emulsions are due to these toxic mediators.
Iodinated lipid emulsions are highly efficient macrophage imaging agents. Nevertheless, none of them has been accepted for clinical use because of adverse reactions. We have tested a new iodinated lipid emulsion, Intraiodol. The size and surface properties of the particles of this emulsion are similar to those of Intralipid which in turn closely resemble the naturally occurring chylomicrons. Using computed tomography (CT) of the rabbit liver as well as vital microscopy and electron microscopy of the rat liver we found that Intraiodol has low efficiency as a liver-specific contrast medium because its particles are predominantly taken up by the hepatocytes and to a less extent by the Kupffer cells, as is Intralipid. The low efficiency of Intraiodol could be fully compensated by an increase in dosage without any significant effect on sinusoidal blood flow. This in turn suggests that the likelihood of release of toxic mediators (and thereby related adverse reactions from activated macrophages) is reduced. We believe that this new way of delivering iodinated lipid particles to the liver represents an important advance in the search for a non-toxic lipid emulsion for CT of the liver.
The route, distribution and clearance of intraarterially administered Lipiodol in the liver has been the subject of much speculation. The hepatic microcirculation was therefore studied by in vivo microscopy after injection of Lipiodol into the hepatic artery and the portal vein in rats. After intraarterial injection, Lipiodol rapidly entered the portal branches through arterio-portal communications. Lipiodol also passed through the sinusoids from the portal into the hepatic veins and then into the systemic circulation. Sinusoidal congestion occurred when the oil droplets filled the liver microcirculation and resolved as the oil was cleared. It is of clinical significance to note the passage of the oil into the systemic circulation after arterial injection.
A new iodinated lipid emulsion, Intraiodol, for which animal studies have indicated better tolerance than for other iodinated lipid emulsions, was tested in 15 patients with malignant lesions, and in one patient with focal nodular hyperplasia. Repeated CT scans of the liver and spleen and blood tests were performed for 24 hours after intravenous injection of Intraiodol. The uptake of Intraiodol in the liver (peak mean 28.6 HU) was higher than in the spleen (peak mean 21.8 HU). The uptake of Intraiodol in malignant lesions was minimal (peak mean 2.8 HU). The detection rate of hepatic lesions was equal to or better than that achieved by US, CT, and/or CT angiography. However, liver uptake of Intraiodol was low in 2 patients with severe fatty infiltration. Intraiodol produced vascular enhancement up to one hour after injection since it was eliminated slowly from the circulation. The observed adverse reactions consisted of temporary metallic taste in 5 of the patients, fever and exacerbation of back pain in one patient, and transient thrombocytopenia in one patient. Alkaline phosphatase increased (17%, p less than 0.01) only at two hours, and erythrocyte count (6%, p less than 0.05) at 24 hours after injection. Our initial results indicate diagnostic advantages of Intraiodol without serious adverse reactions. Further clinical studies are required to confirm these findings.
Thirty-one children with mediastinal abnormalities--14 malignant lymphomas, 4 other primary malignancies, one metastatic and 12 benign lesions--were examined one or several times using CT, which proved to be effective especially for cysts (5 patients), ductus arteriosus aneurysm (2 patients), and intrathoracic liver (one patient). It also supplied important diagnostic information regarding the extent of disease in malignant thymoma (one patient), in neurinoma (one patient), and in Hodgkin's lymphoma (5 patients). It was found to be useful in the monitoring of treatment of patients with lymphomas, in which a small residue, probably a fibrotic remnant, was invariably seen after completion of chemotherapy and irradiation. It was concluded that when the residue was enlarged, the possibility of relapse and even thymic hyperplasia should be considered. However, if CT was performed under general anaesthesia pseudo-widening of the anterior mediastinum could simulate recurrence. Surgical biopsy was found to be necessary in these cases because fine-needle aspiration biopsy was unsuccessful.