Intravascular Ultrasound-Guided Transvenous Biopsy of Retroperitoneal Lymph Nodes: Efficacy and Safety Compared to Percutaneous CT-Guided Biopsy

Intravascular ultrasound-guided transvenous biopsy (IVUS-TVB) is a recently described technique using intracardiac echocardiography catheter visualization to sample targets adjacent to the IVC or iliac veins using a transjugular liver biopsy kit {1}. Although IVUS-TVB has been shown to be technically feasible, the efficacy and safety have not been directly compared to conventional approaches such as CT-guided percutaneous needle biopsy (CT-PNB) for similar targets. Therefore, the purpose of this study was to compare diagnostic accuracy and adverse event rates for IVUS-TVB versus CT-PNB for retroperitoneal (RP) lymph nodes.


Materials and Methods:

A single institution, retrospective study comparing IVUS-TVB to CT-PNB was conducted. From 12/17/2020 to 8/10/2022, 53 IVUS-TVBs were performed, of which 32 were of RP lymph nodes, a non-overlapping sample from that previously reported {1}. For comparison, a search of CT reports from 1/1/2013 to 1/1/2022, using the terms “retroperitoneal and lymph and needle and biopsy,” was performed, yielding 191 CT-PNB procedures. Patient demographics, lymph node size/location, needle passes, procedure time, diagnostic accuracy, and adverse events were compared via t-tests for quantitative variables and chi-squared or Fisher's exact tests for qualitative variables. The diagnostic accuracy and adverse event rate for IVUS-TVB were compared to CT-PNB as the reference standard using the Farrington-Manning non-inferiority test assuming a 10% non-inferiority margin.

Results:

There was no significant difference in age, Charlson comorbidity score, or number of needle passes between groups. IVUS-TVB targets were slightly smaller (2.4 vs 2.7 cm, long-axis, p=0.04, 1.7 vs 2.0 cm, short-axis, p=0.04) and primarily precaval (34%) or aortocaval (47%) in location (vs predominantly left periaortic (80%) for CT-PNB, p< 0.001). Procedure time was approximately 33% longer for IVUS-TVB (64 vs 48 minutes, p< 0.001). Diagnostic accuracy, defined as diagnostic of malignancy or a clinically verifiable benign result, was 94% for IVUS-TVB compared to 88% for CT-PNB.  Overall adverse event rate for IVUS-TVB was 3.1% compared to 3.7% for CT-PNB. IVUS-TVB was non-inferior to CT-PNB for both diagnostic accuracy (p=0.02) and adverse event rate (p=0.04).

Conclusion:

This study demonstrated non-inferiority of IVUS-TVB compared to CT-PNB with respect to diagnostic accuracy and adverse event rate for biopsy of RP lymph nodes adjacent to the IVC. These data suggest that IVUS-TVB is as safe and effective as a conventional biopsy approach such as CT-PNB for similar targets.