An interventional study of CT guided strategy in Severe Aortic Valve Stenosis, sponsored by St. Antonius Hospital. Recruiting at 1 site in Netherlands. Open to participants aged 18 Years to 110 Years. Per ClinicalTrials.gov, last updated 2026-05-19.
Sponsored by St. Antonius Hospital · Not applicable, Interventional, and Treatment
The POPular ATLANTIS trial aims to investigate CT-guided antithrombotic therapy compared to lifelong single antiplatelet therapy after a transcatheter aortic valve implantation (TAVI) procedure. Only patients without an indication for anticoagulants will be included in this trial. Currently, lifelong single antiplatelet therapy (mostly aspirin) is considered the standard of care for these patients. However, this approach poses a bleeding risk with only a minimal reduction in thromboembolic events.
After 3 months, a CT scan will be conducted to assess the presence of thrombosis on the newly implanted TAVI valve. Based on the results of a 4D CT scan, the decision will be made whether the patient should receive no anticoagulant or antithrombotic therapy with apixaban. CT-guided antithrombotic therapy holds the potential for a greater reduction in thromboembolic events without increasing the bleeding risk.
1,025 studies on the registry are indexed under Aortic Valve Stenosis; 293 are open to participants now.
This study's planned enrollment of 2,500 is above the median of 126 across 554 interventional studies indexed under Aortic Valve Stenosis.
Browse Aortic Valve Stenosis studies →St. Antonius Hospital is the lead sponsor of 97 studies on the registry; 28 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Creatinine clearance (CrCl)
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The intervention group will undergo CT scan after 3 months. If subclinical valve thrombosis is detected, anticoagulation will be started. If no subclinical valve thrombosis is detected, the SAPT is stopped, unless another indication is present.
Radiation: CT guided strategy
Standard of care with lifelong SAPT after TAVI
1. With signs of subclinical valve thrombosis on 4D-CT at 3 months after TAVI are switched from SAPT to apixaban. Patients fulfilling the dose reduction criteria according to the drug label, or with a Clinical Frailty Scale ≥4 will receive 2.5mg bid, patients not meeting these criteria will receive a standard dose of 5mg bid. 2. Without signs of subclinical valve thrombosis on 4D-CT at 3 months after TAVI, without another indication for antiplatelet therapy stop their SAPT. 3. Without signs of subclinical valve thrombosis on 4D-CT at 3 months after TAVI with another indication for antiplatelet therapy continue life-long SAPT.
Thromboembolic events
Composite of cardiovascular death, ischaemic stroke, transient ischaemic attack, myocardial infarction, systemic embolism and clinically significant valve thrombosis according to the VARC-3 criteria
Time frame: Through study completion, a median of 2.5 years
All bleeding
Defined as the composite of type 1-4 bleeding, according to the VARC-3 criteria
Time frame: Through study completion, a median of 2.5 years
Net clinical benefit, defined as the composite of cardiovascular mortality, stroke, transient ischaemic attack, systemic embolism, clinically significant valve thrombosis and type 1-4 bleeding according to the VARC-3 criteria
Time frame: Through study completion, a median of 2.5 years
Major bleeding (VARC-3 type 2-4)
Time frame: Through study completion, a median of 2.5 years
Cerebrovascular events (All stroke and TIA according to VARC-3)
Time frame: Through study completion, a median of 2.5 years
Cardiovascular mortality
Time frame: Through study completion, a median of 2.5 years
All-cause mortality
Time frame: Through study completion, a median of 2.5 years
Aortic bio-prosthetic valve dysfunction assessed by echocardiography yearly after TAVI (standard care), as assessed according the VARC-3 criteria for Bioprosthetic Valve Dysfunction.
Bioprosthetic Valve Dysfunction can be split into 'Structural Valve Deterioration' Non-Structural Valve Dysfunction', 'Thrombosis' and 'Endocarditis'. For exact definitions of the sub-groups, VARC-3 criteria can be consulted.
Time frame: Through study completion, a median of 2.5 years
Quality of life as assessed by EuroQol- 5 Dimension 5 Level (EQ-5D-5L) at baseline, 3 and 12 months, and then yearly after TAVI procedure.
The EQ-5D-5L is a standardized health-related quality of life instrument that assesses individuals across five dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. It generates a health profile that can be converted into a single index value, commonly ranging from -0.594 to 1, where 1 represents full health, 0 indicates a state equivalent to death, and negative values reflect health states perceived as worse than death.
Time frame: Through study completion, a median of 2.5 years
Quality of life as assessed by Kansas City Cardiomyopathy Questionnaire (KCCQ) at baseline, 3 and 12 months, and then yearly after TAVI procedure.
The Kansas City Cardiomyopathy Questionnaire (KCCQ) is a disease-specific instrument assessing heart failure patients across domains such as Total Symptoms, Physical Limitation, and Quality of Life, with scores ranging from 0 to 100. Higher scores indicate better health-related quality of life, while lower scores suggest increased symptomatology and functional limitations in heart failure patients.
Time frame: Through study completion, an median of 2.5 years
Quality of life as assessed by Short Form Health Survey (SF-12) at baseline, 3 and 12 months, and then yearly after TAVI procedure.
The Short Form 12 (SF-12) is a widely used health survey that measures health-related quality of life across physical and mental domains. It generates two summary scores, the Physical Component Summary (PCS) and the Mental Component Summary (MCS), both ranging from 0 to 100, where higher scores indicate better health status, and these summaries provide a concise assessment of an individual's overall physical and mental well-being.
Time frame: Through study completion, a median of 2.5 years
Medication adherence as assessed by the Medication Adherence Report Scale (MARS-5) yearly after randomization.
The Medication Adherence Report Scale (MARS) is a self-report questionnaire designed to assess medication adherence in patients. It consists of five items, and scores range from 1 to 5 for each item, with higher scores indicating better medication adherence. Interpretation involves understanding that higher total scores on the MARS reflect a higher level of adherence to prescribed medications.
Time frame: Through study completion, a median of 2.5 years
Cost-effectiveness assassment of a CT-guided antithrombotic strategy after TAVI using EQ-5D-5L
The EQ-5D-5L questionnaire measures health status across five dimensions, providing a standardized index value that is widely used in cost-effectiveness analyses, particularly for estimating Quality-Adjusted Life Years (QALYs) and assessing the impact of healthcare interventions on health-related quality of life.
Time frame: Through study completion, a median of 2.5 years
Plan to share: Undecided
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