Duplex Ultrasound Diagnosis and Follow-Up of Nutcracker Syndrome

Abstract

Introduction Nutcracker syndrome (NCS), also referred to as left renal vein entrapment, is characterized by left renal vein compression between the superior mesenteric artery and aorta. Treatment usually involves renal vein percutaneous angioplasty with or without stent placement. Patients frequently present to the vascular laboratory with vague complaints including various symptoms such as pelvic pain and hematuria. Duplex ultrasound (DU) can play a vital role in the initial diagnosis as well as serial follow-up post-intervention. Case Report Two female patients presented to our laboratory with symptoms ranging from left flank pain, lower quadrant pain, pelvic pain, and microscopic hematuria. Patient 1 was referred by her urologist. Patient 2 was referred after the computed tomography (CT) scan for left side pain indicated possible NCS. Inferior vena cava (IVC) duplex exams were performed with a Phillips iU22 using a C5-1 MHz curved transducer. DU revealed increased velocities in the left renal veins of each patient. Also, the renal veins appeared to be externally compressed. Subsequent venograms with intravascular ultrasound (IVUS) confirmed left renal vein stenosis in both patients. Left renal vein stents were placed in the patients. The stents were evaluated using DU within 1 week of intervention yielding excellent results. Discussion DU was useful in the diagnosis of both patients. If left untreated, NCS can cause damage to the left kidney leaving patients in pain for the rest of their lives. Several diagnostic modalities should be considered for diagnosis of this disease including IVC and renal DU, CT scan, magnetic resonance imaging, and venogram with IVUS. Conclusion NCS patients often present with vague symptoms and diagnosis can be difficult. When NCS is clinically suspected, DU is an excellent primary diagnostic method with which to identify renal vein compression. Following intervention, DU can successfully ensure patency of the renal vein stent with serial follow-up exams.