Background: Renal vein thrombosis (RVT) is the most frequent site of primary venous thrombosis in neonates. At present, there is no conventional therapeutic regimen for this condition.

Objective: To establish current clinical guidelines based on data from the Canadian Pediatric Hemostasis and Thrombosis Network (CPHTN).

Materials and Methods: A standardized questionnaire was sent to CPHTN members involved with pediatric thrombosis care. Clinical variables included thrombus location (unilateral vs. bilateral), severity (non-occlusive vs. occlusive), extension to the inferior vena cava (IVC+), and concomitant bleeding at diagnosis [i.e. hematuria with thrombocytopenia (H/T+), with/without ≥ grade 2 intraventricular hemorrhage (IVH+/−)].

Results: A total of 16 pediatric hematologists participated, with a response rate of approximately 80%. Regarding diagnostic imaging, the most utilized methods were the following: a) Doppler ultrasound (U/S) in 14/16 (87.5%); b) U/S without Doppler in 1/16 (6.25%); and c) contrast venography in 1/16 (6.25%). 12/16 (75%) of the physicians would have ordered a thrombophilia work up. For unilateral, non-occlusive, H/T− or H/T+ cases, management included, respectively: 1) no therapy in 11/16 (68.75%) and 9/16 (56.25%); 2) low-molecular-weight heparin (LMWH) in 2/16 (12.5%) (3-month-course) and 3/16 (18.75%) (14-day or 3-month course); and 3) therapy based on radiologic follow up (f/u) in 3/16 (18.75%) and 4/16 (25%). For unilateral, occlusive, H/T+, IVH− or IVH+ cases, management included: 1) no therapy in 5/16 (31.25%) and 10/16 (62.5%); 2) LMWH in 6/16 (37.5%) and 4/16 (25%); and 3) treatment based on f/u findings in 5/16 (31.25%) and 2/16 (12.5%). For bilateral, occlusive, IVC−, IVH− cases, management included: 1) LMWH (2 weeks to 3 months) in 12/16 (75%); 2) tissue-plasminogen activator (t-PA) in 1/16 (6.25%); 3) LMWH and t-PA in 2/16 (12.5%); and 4) therapy based on f/u in 1/16 (6.25%). Finally, for bilateral, occlusive, IVC+, IVH− or +, the responses were, in that order: 1) LMWH (6 weeks to 3 months) in 10/16 (62.5%) and 11/16 (68.75%); 2) t-PA in 3/16 (18.75%) and 0/16; 3) LMWH and t-PA in 2/16 (12.5%) and 0/16; 4) treatment based on f/u in 1/16 (6.25%) in both groups; 5) no therapy in 2/16 (12.5%) of the latter group only; and 6) unknown in 2/16 (12.5%) of the latter group only. The anti-Xa level (0.5 to 1.0 range) was the only assay suggested for monitoring LMWH. Standard heparin was monitored by anti-Xa levels in only 3/16 (18.75%) of cases. Consultation sources included 1) combined sources (i.e. books, protocols, journals) in 10/16 (62.5%) cases; 2) journals in 4/16 (25%) cases; and 3) 1-800-NO-CLOTS in 2/16 (12.5%) cases. 15/16 (93.75%) of the participating physicians supported the idea of developing therapeutic protocols.

Conclusions: Currently, there are no standard therapeutic practices with respect to neonatal RVT. It would be difficult to successfully complete a randomized clinical trial due to small numbers. However, multicenter, prospective studies utilizing consistent therapeutic approaches would be extremely helpful in this clinical setting.

Author notes

Corresponding author

Sign in via your Institution