Background: Agenesis of inferior vena cava (AIVC) is a rare anomaly which increases the risk of thrombosis. Although the cause of AIVC is not known, it might be associated to intrauterine/perinatal thrombosis. We recently described a high penetrance of AIVC (70.8%) in severe thrombophilia secondary to homozygous antithrombin Budapest3.
Aims: To build a multicentre registry of patients with AIVC (the IVC Agenesis Study), aimed at improving knowledge on the associated thrombotic risk and underlying thrombophilias.
Methods: Systematic search of cases with radiologic evidence of AIVC was conducted in 15 hospitals from Spain and Portugal, using automated data-extraction software in free-text image reports from 2010-2021. Radiologic and clinical variables were collected.
Results: We recruited 178 AIVC patients (Table1). One hundred (56.5%) developed thrombosis, with early (median: 33.7 y.o.) and recurrent (33.0%) events. Only 48 (27.0%) had been referred for thrombophilia screening, and 19 (39.6%) carried a thrombophilic defect. Forty-eight (27.0%) subjects had isolated hepatic AIVC, while 130 (73.0%) had infrarenal involvement. Demographics were similar among groups, but cases with infrarenal AIVC showed higher thrombotic rate (66.9% vs. 27.7%, p < 0.0001) and more severe clinical phenotype (Table1). Thrombosis associated to infrarenal AIVC tended to be located at lower extremities, as well as to have earlier onset and higher recurrence than those secondary to hepatic AIVC. Moreover, the profile of associated congenital malformations significantly differed between groups (Table1).
Conclusion(s): Our results demonstrate the existence of two forms of AIVC, with distinct thrombotic phenotypes. Different molecular and thrombophilic defects might be explored in these groups. But more remarkably, our findings show that, despite having high thrombotic risk, these patients remain out-of-the-scope of hematologists. Our work supports the use of thromboprophylaxis in high-risk situations, and of long-term anticoagulation in symptomatic cases. Multidisciplinary management and future studies assessing the clinical utility of thrombophilia screening in AIVC should be guaranteed.
Funding:ISCIII&FEDER:PI21/00174,CM20/00094.SETH:Premio López-Borrasca/2021
Table 1. Clinical data and thrombotic history of the overall cohort of AIVC patients -Nf178- and comparison of cases with hepatic vs. infrarenal AIVC
To cite this abstract in AMA style:
Bravo-Pérez C, Blanco A, Revilla N, Asenjo S, Bonanad S, Castro N, Marcellini S, López-Sala P, Palomino D, Infante M, Corral M, Rodriguez-Sevilla J, Rodríguez-Alen A, Sevivas T, Morello D, Vicente V, Lozano M, de la Morena-Barrio M, García-Santos J, Corral J. The severe thrombophilic state associated to inferior vena cava agenesis: data from a multicentre cohort of 178 patients from the IVC Agenesis Study Group Registry [abstract]. https://abstracts.isth.org/abstract/the-severe-thrombophilic-state-associated-to-inferior-vena-cava-agenesis-data-from-a-multicentre-cohort-of-178-patients-from-the-ivc-agenesis-study-group-registry/. Accessed March 21, 2024.« Back to ISTH 2022 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/the-severe-thrombophilic-state-associated-to-inferior-vena-cava-agenesis-data-from-a-multicentre-cohort-of-178-patients-from-the-ivc-agenesis-study-group-registry/