Volume 49, Issue 3 Fall 2025 JVU 493-161 | Standardized Protocol for Assessing Left Renal Vein Compression Using Diagnostic Ultrasound-Standardized Protocol

Standardized Protocol

Pdf Summary

This 2025 Journal for Vascular Ultrasound article by Nagarsheth et al. addresses the diagnostic challenges in evaluating left renal vein (LRV) compression, or nutcracker syndrome, a vascular compression disorder where the LRV is compressed primarily between the abdominal aorta and superior mesenteric artery (SMA). This leads to venous hypertension, collateral vein formation, and symptoms including hematuria, pelvic pain, flank discomfort, and positional symptoms exacerbated by standing. Diagnosis is difficult due to nonspecific, variable symptoms and overlapping conditions.<br /><br />The authors emphasize that duplex ultrasound is a preferred initial, noninvasive imaging modality for assessing nutcracker syndrome, as it offers real-time evaluation of blood flow and vascular anatomy. However, its diagnostic accuracy has been limited by inconsistent imaging techniques, operator variability, and lack of standardized measurement criteria for key parameters like vessel diameter ratios, Doppler velocity ratios, and the aortomesenteric angle.<br /><br />To address this, the article proposes a standardized duplex ultrasound protocol developed at their institution, aimed at improving diagnostic consistency and early recognition of LRV compression. Key components include using curvilinear transducers (2-5 MHz), specific patient positioning (supine and standing), detailed grayscale, color Doppler, and spectral Doppler imaging at multiple anatomical points (renal hilum, aortomesenteric junction, inferior vena cava), and systematic measurement of peak systolic and end-diastolic velocities, vessel diameter ratios, and aortomesenteric angles. The protocol emphasizes strict Doppler angle correction (0° or 60°), documentation of positional changes, and identification of collateral veins.<br /><br />The authors note that formal notification of critical findings should be immediate, with structured reporting and use of standardized terminology. They highlight that standardized protocols reduce operator-dependent variability, guide patient selection for further imaging or intervention, and facilitate longitudinal monitoring. While current Society for Vascular Ultrasound guidelines provide general frameworks, this protocol builds upon them with more specific diagnostic thresholds validated for nutcracker syndrome.<br /><br />In conclusion, the article advocates widespread adoption and further validation of standardized duplex ultrasound protocols to enhance early diagnosis, improve interobserver reproducibility, streamline clinical workflows, and ultimately guide optimal management of patients with suspected left renal vein compression.

Keywords

Nutcracker syndrome

Left renal vein compression

Duplex ultrasound

Vascular ultrasound protocol

Aortomesenteric angle

Doppler velocity ratios

Venous hypertension

Collateral vein formation

Standardized imaging techniques

Diagnostic challenges