Superior vena cava syndrome in chronic intestinal failure patients: When the going gets tough

BACKGROUND & AIMS

Catheter-related venous thrombosis is a severe complication of home parenteral nutrition (HPN) with potentially devastating consequences such as superior vena cava syndrome (SVCS). Early recognition and awareness of factors leading to its development are of paramount importance. However, studies are lacking in HPN patients focusing on this topic. In this study, we aimed to determine the incidence of SVCS in HPN patients and describe SVCS-related outcomes.

METHODS

This retrospective cohort study comprised all adult HPN patients who developed SVCS between 2000 and 2022 at our national HPN referral center. Primary outcome was the incidence of SVCS. Secondary outcomes include SVCS-related symptoms, tip location of central venous access device (CVAD) post-insertion and at time of SVCS, diagnostics and treatment.

RESULTS

SVCS was diagnosed in 38 of 616 patients (6%), with an annual cumulative incidence rate ranging between 0 and 4.2%. Most common presenting symptoms were facial edema (82%) and arm edema (50%). Post-insertion, 17% (6/36) of patients had a correct position of the CVAD tip and 11% (4/36) during SVCS diagnosis. Computed tomography was the most used diagnostic imaging technique (66%). Sixty-three percent of patients started, 11% switched, and 21% continued anticoagulant treatment.

CONCLUSIONS

The incidence of SVCS is relatively high in our vulnerable HPN population. It is key to recognize whenever such patients present with vascular obstruction-related symptoms and treat them in an early stage by a multidisciplinary team.

Identification and in vivo characterization of a brain-penetrating nanobody

Background

Preclinical models to determine blood to brain transport ability of therapeutics are often ambiguous. In this study a method is developed that relies on CNS target-engagement and is able to rank brain-penetrating capacities. This method led to the discovery of an anti-transferrin receptor nanobody that is able to deliver a biologically active peptide to the brain via receptor-mediated transcytosis.

Methods

Various nanobodies against the mouse transferrin receptor were fused to neurotensin and injected peripherally in mice. Neurotensin is a neuropeptide that causes hypothermia when present in the brain but is unable to reach the brain from the periphery. Continuous body temperature measurements were used as a readout for brain penetration of nanobody-neurotensin fusions after its peripheral administration. Full temperature curves were analyzed using two-way ANOVA with Dunnett multiple comparisons tests.

Results

One anti-transferrin receptor nanobody coupled to neurotensin elicited a drop in body temperature following intravenous injection. Epitope binning indicated that this nanobody bound a distinct transferrin receptor epitope compared to the non-crossing nanobodies. This brain-penetrating nanobody was used to characterize the in vivo hypothermia model. The hypothermic effect caused by neurotensin is dose-dependent and could be used to directly compare peripheral administration routes and various nanobodies in terms of brain exposure.

Conclusion

This method led to the discovery of an anti-transferrin receptor nanobody that can reach the brain via receptor-mediated transcytosis after peripheral administration. This method could be used to assess novel proteins for brain-penetrating capabilities using a target-engaging readout.

Randomised clinical trial: 2% taurolidine versus 0.9% saline locking in patients on home parenteral nutrition

BACKGROUND

The catheter lock solutions 2% taurolidine and 0.9% saline are both used to prevent catheter-related bloodstream infections (CRBSIs) in home parenteral nutrition patients.

AIMS

To compare the effectiveness and safety of taurolidine and saline.

METHODS

This multicentre double-blinded trial randomly assigned home parenteral nutrition patients to use either 2% taurolidine or 0.9% saline for 1 year. Patients were stratified in a new catheter group and a pre-existing catheter group. Primary outcome was the rate of CRBSIs/1000 catheter days in the new catheter group and pre-existing catheter group, separately.

RESULTS

We randomised 105 patients, of which 102 were analysed as modified intention-to-treat population. In the new catheter group, rates of CRBSIs/1000 catheter days were 0.29 and 1.49 in the taurolidine and saline arm respectively (relative risk, 0.20; 95% CI, 0.04-0.71; P = 0.009). In the pre-existing catheter group, rates of CRBSIs/1000 catheter days were 0.39 and 1.32 in the taurolidine and saline arm respectively (relative risk, 0.30; 95% CI, 0.03-1.82; P = 0.25). Excluding one outlier patient in the taurolidine arm, mean costs per patient were $1865 for taurolidine and $4454 for saline (P = 0.03). Drug-related adverse events were rare and generally mild.

CONCLUSIONS

In the new catheter group, taurolidine showed a clear decrease in CRBSI rate. In the pre-existing catheter group, no superiority of taurolidine could be demonstrated, most likely due to underpowering. Overall, taurolidine reduced the risk for CRBSIs by more than four times. Given its favourable safety and cost profile, taurolidine locking should be considered as an additional strategy to prevent CRBSIs.

TRIAL REGISTRATION

Clinicaltrials.gov, identifier: NCT01826526.