An observational study in Thromboembolic Disease, sponsored by Larissa University Hospital. Not yet recruiting. Open to participants aged 18 Years to 78 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-02-11.
Sponsored by Larissa University Hospital · Observational
The goal of this observational study is to learn if certain factors in a person's blood are linked to a history of venous thromboembolic disease (VTED), which includes conditions like deep vein thrombosis.
Lewis system antigens are natural markers found on red blood cells. Past research suggests that people without these specific markers might have a higher chance of developing heart disease, but the link to blood clots in veins is not well understood.
This study aims to answer:
Researchers will also record other known risk factors for VTED for each participant. This study is self-funded.
Background Since 1992, research has reported a correlation between Lewis antigens and cardiovascular disease, primarily linked to increased endothelial activation in individuals who are Lewis a(-) b(-). Experimental studies in mice suggest an association between the FUT4 and FUT7 genes and the occurrence of venous thromboembolic disease (VTED), but there is a lack of in vivo studies on this subject in humans . This study aims to fill this knowledge gap by investigating this relationship in a clinical setting.
Study Objectives The primary objective is to investigate the relationship between Lewis system antigens and a personal history of VTED. The study will also assess the association between specific Lewis antigen phenotypes and other known risk factors for VTED.
Study Design This is an independent and self-funded, single-center, observational study (p. 1). Lewis a and b antigens will be identified serologically in a specific patient population, and these results will be correlated with existing clinical data on thrombophilia and other VTE risk factors Study Population and Setting The study will include 100 participants (goal sample size for 90% statistical power) with a personal history of deep vein thrombosis, regardless of whether they have hereditary or acquired thrombophilia . All participants are monitored at the Haemostasis Disorders Clinic of the Blood Transfusion Service at the University Hospital of Larissa, Greece. Written informed consent is obtained from all participants after they are fully informed about the study.
Methods and Outcome Measures Lewis antigens are identified using commercial reagents and gel cards from Grifols.
Primary Outcome Measure: The prevalence of different Lewis erythrocyte antigen phenotypes in patients with a history of VTED. (Time Frame: At the time of a single blood draw) Secondary Outcome Measure: The correlation between Lewis phenotypes and the presence of other known VTE risk factors or a confirmed diagnosis of thrombophilia. (Time Frame: Assessed using existing medical records at the time of a single blood draw) Statistical Analysis Statistical analysis will be performed using the SPSS software package.
288 studies on the registry are indexed under Thromboembolism; 42 are open to participants now.
This study's planned enrollment of 200 is below the median of 440 across 121 observational studies indexed under Thromboembolism.
Browse Thromboembolism studies →Larissa University Hospital is the lead sponsor of 41 studies on the registry; 7 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Pateints with personal history of VTE
Inclusion Criteria:
Exclusion Criteria:1. Current pregnancy or postpartum period 2. Hepatic insufficiency 3. Alcoholic cirrhosis
-
BLODD SAMPLING
CONTROL GROUP- HEALTHY BLOOD DONORS
The aim of this study is to investigate the relationship between Lewis system antigens and venous thromboembolic disease (VTED).
Lewis a and b antigens will be identified in patients with a personal history of deep vein thrombosis, with or without hereditary or acquired thrombophilia, who are being monitored at the Haemostasis Disorders Clinic of the Blood Transfusion Service of the University Hospital of Larissa. All patients, after being informed, will submit written consent for their participation in the study. Lewis antigens will be identified serologically using reagents and gel cards from Grifols. The results of the thrombophilia test and other known risk factors for VTE will be recorded. Statistical analysis will be performed using the SPSS package.
Time frame: From enrollment to the day of blood phenotyping- approximately 48 hours
PRESENCE OF LEWIS A AND B ANTIGEN ON ERYTHROCYTE
NEGATIVE OR POSITIVE FOR LEWIS ANTIGENS
Time frame: From enrollment to the day of blood antigen phenotyping- approximately 48 hours
No study locations are listed for this record.
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No — Our study does not plan to share Individual Participant Data (IPD) primarily due to strict limitations in the original informed consent process; participants did not grant permission for their data to be shared externally.
Start is estimated for Jan 2026; primary completion for Jan 2027, 11 months later.
Of 46 observational studies under Thromboembolism, half reached primary completion within 39 months of starting (the median), counting those still running; a quarter within 24 and three quarters within 65. This study's planned 11 months is below that.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Feb 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Larissa University Hospital