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Renal artery aneurysms are more common in patients with fibromuscular dysplasia (FMD). Although these aneurysms have traditionally been managed surgically, endovascular techniques are playing a larger role. Many treatment methods involve the use of stent-grafts to exclude the aneurysm or bare stents to protect the main renal artery while coil embolization is performed through the interstices. Herein, the authors present a patient with an arteriovenous fistula secondary to FMD that was managed entirely with use of detachable coils, which allowed preservation of the uninvolved renal parenchyma.
Experience with the diagnostic evaluation and operative management of 38 hypertensive patients having bilateral renal revascularization is presented. Twenty-four patients had atherosclerotic occlusions and 14 had fibromuscular dysplasia. Renal vein renin assays (RVRA) and/or split renal function studies (SRFS) were performed in 37 of the 38 patients before operation. Although RVRA was negative in 29 percent and SRFS negative in 31 percent, 24 of 26 patients (92 percent) having both tests done had at least one positive study. Twenty-one patients had simultaneous bilateral repairs and 12 had staged bilateral reconstructions. The incidence of technical failures in these two groups was 21 and 9 percent, respectively. Excluding three uncorrected technical failures and two patients with recurrent branch renal artery lesions, 90 percent of patients with atherosclerosis and all patients with fibromuscular dysplasia had a favorable blood pressure response to operation. This study supports the use of both RVRA and SRFS in the diagnostic evaluation of hypertensive patients with renal artery stenosis. If these functional tests lateralize to one side, repair of that side only is recommended. If the functional studies do not lateralize, operation is suggested only when hypertension is severe and is not controlled readily with medications. In this circumstance reconstruction of the side that appears to be diseased most severely is recommended. Contralateral repair is undertaken only when hypertension persists and when repeat functional studies lateralize to the unoperated side.
As the population requiring hemodialysis grows, it becomes increasingly common to encounter patients with limited options for vascular access. Because inability to secure vascular access is a life-threatening problem, it is important to consider all possible options in each patient. We report a new arteriovenous grafting procedure in which the left renal vein is used for outflow in a patient with multiple venous occlusions. Patency of the graft continues 18 months after placement. This graft carries acceptable morbidity, and can be revised. Consideration of this graft is appropriate in selected patients.
PURPOSE - To prospectively compare the diagnostic accuracy of CO(2) and gadolinium to iodinated contrast material for inferior vena cavography before inferior vena cava (IVC) filter placement.
MATERIALS AND METHODS - Forty patients underwent injection of iodinated contrast material, CO(2), and gadolinium. Iodinated contrast material was used as the standard. Caval diameter was determined with calibrated software. Three readers blinded to contrast agent used measured the distance from the superior image border to the inferior margin of the renal veins and from the inferior image border to the iliac bifurcation. The measurements with CO(2) and gadolinium were compared to those with iodinated contrast material to obtain the interobserver and intraobserver variability. The presence or absence of caval thrombus and variant anatomy was noted. The same readers reexamined 12 studies in a separate session to determine intraobserver variability and correlation.
RESULTS - Caval diameter differed by 0.4 mm or less for all three agents. Measurements with all agents were within 2 mm of each other for all patients. Gadolinium and CO(2) were not significantly different from one another in measuring caval diameter. At the initial reading, compared with iodinated contrast material, gadolinium had greater mean interobserver error in measuring the distance to the iliac bifurcation and both renal veins (range, 1.6-1.8 mm) than CO(2) (range, 0.2-1.4 mm). This finding, although statistically significant for gadolinium (P <.05), was of doubtful clinical relevance. Interobserver correlation was significantly worse for CO(2) at the levels of the iliac bifurcation (P =.02) and right renal vein (P =.008). Interobserver correlation for gadolinium was similar to that for iodinated contrast material at all levels. At repeat reading, there was significantly inferior intraobserver correlation with use of CO(2) for both renal veins (P <.05) compared to iodinated contrast material and for the left renal vein (P <.05) compared to gadolinium. Gadolinium identified three of three renal vein anomalies identified with iodinated contrast material whereas CO(2) localized one of three.
CONCLUSION - CO(2) and gadolinium had limitations when compared with iodinated contrast material. Gadolinium provided superior consistency in identifying relevant landmarks for filter placement. CO(2) demonstrated significantly greater mean correlative error than gadolinium at initial and repeat readings.
The systemic complications of nephrotic syndrome are responsible for much of the morbidity and mortality seen with this condition. This review discusses the causes for the hypoalbuminemia and the associated metabolic abnormalities of the nephrotic syndrome. No unifying hypothesis exists for the induction, maintenance, and resolution of nephrotic edema. In view of the wide spectrum of renal diseases leading to the nephrotic syndrome, more than a single mechanism may be responsible for the renal salt retention in these diverse conditions. Although hypoalbuminemia may be important, especially when plasma oncotic pressure is very low (serum albumin < 1.5 to 2.0 g/dL), primary impairment of salt and water excretion by the nephrotic kidney appears to be a major factor in pathogenesis of the edema. However, the decreased serum albumin and/or oncotic pressure seen with nephrotic syndrome is a major contributing factor to the development of the hyperlipidemia of nephrotic syndrome. Patients with unremitting nephrotic syndrome should be considered for combined dietary and lipid-lowering drug therapy. Urinary losses of binding proteins lead to the observed abnormalities in the endocrine system and in trace metals, and urinary losses of coagulation factors contribute to the hypercoagulable state. At present, selective renal venography is recommended when the suspicion of renal vein thrombosis is justified by clinical presentation. The impact on renal function caused by treating asymptomatic chronic renal vein thrombosis is undetermined, but anticoagulation for chronic renal vein thrombosis is associated with relatively few complications.
The relationship between renal prostaglandin (PG)I2 biosynthesis and renin release was examined in conscious dogs before and during renal artery constriction. Dogs were chronically instrumented with femoral vein, femoral artery and left renal vein catheters and an inflatable cuff and electromagnetic flow probe were positioned on the left renal artery. After 2 days, mean arterial blood pressure, heart rate, renal blood flow and renal secretion rates of renin and 6-keto-PGF1 alpha were determined before and 10 min after a reduction in renal blood flow. Plasma levels of 6-keto-PGF1 alpha, measured by a gas chromatographic-mass spectrometric assay, were used as an index of PGI2 synthesis. A 38% reduction in renal blood flow did not significantly alter mean arterial blood pressure, heart rate or arterial levels of plasma renin activity or 6-keto-PGF1 alpha. In contrast, renal artery constriction increased renal venous plasma levels of both renin activity and 6-keto-PGF1 alpha by 308% (P less than .002) and 132% (P less than .05), respectively. As a consequence, the renal secretion rate of renin was increased from 80 +/- 40 to 917 +/- 231 ng of angiotensin I . min-1 . hr-1 (P less than .02) and the renal secretion rate of 6-keto-PGF1 alpha was increased from -2.1 +/- 1.1 to 9.0 +/- 3.6 ng/min (P less than .05). In addition, there was a significant correlation between the renal secretion rates of renin and 6-keto-PGF1 alpha (r = 0.688; P less than .013; n = 12). These data indicate a close association between the renal biosynthesis and PGI2 and renin release and are consistent with the concept that PGI2 participates in the release of renin.