The impact of knee joint flexion on infrainguinal vascular grafts: an angiographic study.

OBJECTIVES: To characterise the morphologic behaviour of infrainguinal vascular grafts during flexion of the knee. DESIGN: A prospective angiographic study. MATERIALS AND METHODS: In 64 infrainguinal bypass grafts, intravenous digital subtraction angiography was performed within the first postoperative week. Frontal and lateral projection angiograms with the knee joint extended and with a 80-90 degrees flexion were taken. The distal anastomosis of the bypass was performed below-knee in 49 cases (18 in situ veins, 8 reversed veins with an anatomic course, 2 reversed veins with an extra-anatomic course, 4 composite grafts, 15 synthetic grafts with an anatomic course (14 polytetrafluoroethylene (ePTFE), 1 polyurethane), and two synthetic grafts with an extra-anatomic course. Fifteen ePTFE prostheses were implanted in the above-knee position. RESULTS: Out of 64 cases a total of 16 grafts showed stenotic kinking during flexion: two of the 18 in situ vein grafts, four of the 12 reversed vein grafts implanted with an anatomic course, one of the two reversed vein grafts implanted in an extra-anatomic site, eight of the 15 synthetic grafts crossing the knee, 0 of the two extra-anatomic ePTFE grafts, and one of the 15 cases of above-knee femoropopliteal ePTFE grafts. CONCLUSIONS: Stenotic kinking due to knee flexion can affect all kinds of bypass grafts including vein grafts placed anatomically and above-knee prostheses.

[Endovascular treatment of hemorrhagic renal angiomyolipoma with platinum microcoils]. / Traitement endovasculaire d'un angiomyolipome rénal hémorragique par microcoil de platine.

Haemorrhage is the major complication of renal angiomyolipoma and is classically treated surgically, but embolization constitutes an alternative treatment. Improvement of catheters and embolization materials now allows highly selective embolization. The authors present a case in which the use of a variable stiffness catheter and platinum microcoils allowed highly selective embolization of a haemorrhagic renal angiomyolipoma while preserving the functional renal parenchyma.

[X-ray computed tomographic tests in the diagnosis and treatment of amebic liver abscesses]. / Apport de l'examen tomodensitométrique pour le diagnostic et le traitement des abcès ambiens du foie.

PURPOSE: The aim of this study was to evaluate the CT findings of amebic liver abscesses and its usefulness for treatment. METHODS: CT was performed in 51 patients with proved amebic liver abscess. CT studies were made before and after contrast injection. RESULTS: Among the 98 abscesses, 66% occurred in the right lobe. 66% of the patients presented a solitary abscess. The diameters were found between 2 cms to 15 cms. The mean was 7 cms. An enhancing wall was present in 84%; the margins were festooned in 75%, smooth in the other cases; internal septations were noted in 57%. High density material within the abscess, before injection of contrast was seen in 50%. 30% of patients had focal intra-hepatic biliary dilatation, 27% right pleural effusion, 23% peri-hepatic fluid collection. One hepatic-colic fistula and one hepato-pulmonary fistula were not suspected on U.S. examination. Percutaneous aspiration was done in 31% of the patients, when the diameter of the abscesses were more than 10 cms or when they were seen in the left lobe or when fever or pain did not disappear after treatment. CONCLUSION: CT scan may be helpful in diagnosis of amebic liver abscess at an early stage or later when a complication is suspected. CT scan can also help to indicate and safely perform a percutaneous therapeutic aspiration.

Assessment of painful ureterohydronephrosis during pregnancy by MR urography.

The purpose of this study was to assess the value of the fast imaging sequence called RARE (rapid acquisition with relaxation enhancement) MR urography (or RMU) in pregnant women with painful ureterohydronephrosis. A total of 17 pregnant women with an acute flank pain were examined with RMU. Results were compared with those of US, X-rays and the evolution of symptoms. The gold standard techniques used to evaluate the results of MR urography were US when it showed the entire dilated urinary tract and the nature of the obstruction (9 cases), limited intravenous urography (IVU) when performed (3 cases) or endoscopic procedure (5 cases). The accuracy of RMU in the detection of urinary tract dilatation and the localization of the level of obstruction was excellent (sensitivity 100% in our series). The determination of the type of obstruction, intrinsic vs extrinsic, was always exact. The RMU technique alone could not specify the exact nature of the obstruction. The RMU technique is able to differentiate a physiological from a pathological ureterohydronephrosis during pregnancy. It could be considered as the procedure of choice when US failed to establish the differential diagnosis.

[In situ fibrinolysis of acute arteriovenous shunt obstructions during hemodialysis]. / Fibrinolyse in situ des oblitérations aiguës des fistules artério-veineuses chez les hémodialysés.

Several techniques (surgical revision, thrombectomy, ...) have been described for the treatment of thrombosed vascular access (VA) in hemodialysis patients. We propose a technique with local thrombolytic infusion in conjunction with angiography and percutaneous dilatation and/or recanalization. A total of fourteen patients with twenty-two episodes of thrombosed VA was studied. Eleven patients had a Brescia-Cimino fistula and three patients had a graft fistula. We used in 21 cases urokinase (243000 UI +/- 100000 UI) and in 1 case rt-PA (50 mg). Of the 22 VA, 19 issued in an immediate patency and were restored to full function; and whereof 17 remained patent more than 2 weeks. Failures occurred in 3 cases: localized bleeding from previous dialysis puncture sites (1), venous outflow obstruction (1), and resistant venous stenosis (1). There were no infectious complications, and no systemic bleeding complications. We observed one pseudoaneurysm and one humeral asymptomatic thrombo-embolism. Stenoses were the most frequent factor in precipitating thrombosis. We believe that our technique should be the first line of treatment of occluded hemodialysis vascular access.

Forward and backward waves in the arterial system, their relationship to pressure waves form.

The purpose of this work was to analyze, in human subjects, the shape of the aortic pressure wave from its forward and backward components calculated by use of Westerhof's model. Twenty-nine patients were studied: 11 normal subjects, 11 hypertensive patients and 7 patients with congestive heart failure. The following measurements and calculations were performed both under control conditions and during either angiotensin infusion in 5 normal subjects or nitroprusside infusion in 6 hypertensive patients: cardiac output, aortic blood pressure (catheter tip micromanometer), blood flow velocity (electromagnetic catheter-tip velocity transducer) in the ascending aorta, aortic impedance and reflection coefficients allowing the calculation of the aortic forward and backward pressure waves. The results show that the shape of aortic pressure wave in hypertensive patients is related to increased arterial wall stiffness which determines greater values and overlap of the forward and backward waves. This result is corroborated by the changes observed during angiotensin infusion in normal subjects. The shape of pressure wave in heart failure patients is dicrotic. This shape is related to smaller values and overlap of forward and backward waves. This appears related to a reduced stroke volume. During peripheral vasodilation the shape of pressure wave in hypertensive patients becomes dicrotic. However, this was mainly related to later backward waves. These results confirm that the shape of pressure waves depends both on the arterial wall stiffness and on the left ventricular performance: mainly on the stroke volume. The calculation of forward and backward waves allows a quantitative analysis of pressure waves.