Left Renal Vein Entrapment

Abstract

The propinquity of the left renal vein to the pancreas and retroperitoneal lymph nodes makes this vessel a likely candidate for early involvement in retroperitoneal malignant disease. The practical clinical application of this fortunate anatomical relationship has not previously been exploited despite the ease with which percutaneous selective catheterization of the renal veins may be carried out. In order to test this hypothesis we have in the past three years routinely performed renal phlebography in addition to abdominal panarteriography in all patients suspected of harboring a retroperitoneal malignant tumor. Over 300 patients have been referred to us for study. The results have amply confirmed our expectations and are herein presented. The value of renal phlebography in staging renal carcinoma has been well documented (1) and is not discussed in this paper. Normal Anatomy The left renal vein averages 8.5 cm in length and 1.5 to 2.5 cm in its greatest cephalocaudad diameter at its caval opening. Posteriorly it courses transversely across the renal artery, aorta, and spine; anteriorly it is related to the superior mesenteric artery and inferior mesenteric vein as well as parts of the head, uncinate process, and proximal body of the pancreas. Renal, mesenteric, pancreatic, and aortic lymph nodes also lie in close association with this vein (Fig. 1). Its tributaries include the suprarenal, renal capsular, gonadal, and ureteral veins as well as communications with the second lumbar vein (Fig. 2, A and B). Frequently a dilated third lumbar vein arises directly from the renal vein providing it with important accessory flow pathway to the inferior vena cava (2). The ovarian vein can sometimes be very large (Fig. 3, A) and in pregnancy may possibly provide an accessory route of drainage between the hypogastric vein and the vena cava via the renal vein. In our experience with more than 500 left renal vein catheterizations we have never observed this vein to be significantly compressed within the tight angle formed by the superior mesenteric artery and a normal aorta, although this would seem to be logical especially in the supine position. On occasion, however, especially when the aorta is aneurysmal or severely tortuous, the renal vein does tend to be locally widened as it is stretched ribbon-like over the anterior wall of the aorta (Fig. 3, B). This slight compromise of lumen does not affect renal vein emptying time as defined by Abrams et al. (3) nor cause major diversion of blood to lumbar vein collaterals. The left renal vein normally increases its inferosuperior diameter gradually from hilus to its caval opening by about 10 to 25 per cent. The terminal third of the vein should always be wider than its segment of origin.