Morbidity and Mortality Due to Deferral of Aortic Valve Replacement in Patients With Severe Aortic Stenosis (AS DEFER)
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ClinicalTrials.gov Identifier: NCT04333875 |
Recruitment Status :
Completed
First Posted : April 3, 2020
Last Update Posted : March 14, 2023
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Background and Project Rationale:
Degenerative aortic valve stenosis affects 2% of the elderly population aged 70 years or older and progresses insidiously with advancing age [1] before manifesting with symptoms such as decreased exercise tolerance, shortness of breath, chest pain and syncope on exertion. Without aortic valve replacement, the survival prognosis of patients with symptomatic aortic stenosis is poor. In the PARTNER 1B trial, all-cause mortality among 179 inoperable patients with severe symptomatic aortic stenosis allocated to conservative management amounted to 51% at one year [2]. Consistently, prospective registry data reported a mortality rate of 55% at 1 year in 78 patients with severe aortic stenosis undergoing conservative management [3].
The rapid spread of the SARS-CoV-2 pandemic represents an unprecedented challenge for healthcare systems. A limited number of ventilators and ICU beds call for a careful allocation of healthcare resources. On March 20 2020, the Federal Council prohibited elective interventions in all hospitals in Switzerland. Patients with untreated severe aortic stenosis are particularly vulnerable to SARS-CoV-2 infection [4] and face the dual risk of cardiac death from aortic stenosis on one side, and death from acute respiratory distress syndrome secondary to SARS-CoV-2 infection on the other. While the balance between the two risks is a matter of clinical judgement, the investigators established an algorithm for the management of patients with severe aortic stenosis during the SARS-CoV-2 pandemic. Patients with aortic stenosis deemed critical will undergo valvular replacement in spite of the ongoing pandemic while patients with severe but not critical aortic stenosis will undergo deferred intervention once the number of new SARS-CoV-2 infections flattens.
In the current situation, aortic valve replacement in patients with severe, non-critical aortic stenosis will be deferred in order to give priority to SARS-CoV-2 patients. This unique situation allows the investigators to study the effect of deferral of aortic valve replacement in patients with severe aortic stenosis.
The study is an amendment to the Swiss-TAVI registry. In contrast to the Swiss-TAVI registry, patients are not enrolled at the time of aortic valve replacement, but already at the time of referral for aortic valve replacement.
Primary Objective:
The aim of the present observational study is to explore the effect of deferral of valvular replacement in patients with severe but not critical aortic stenosis on morbidity and mortality. The primary objective is to describe rates of morbidity and mortality among patients with severe but not critical aortic stenosis in the interval from referral/indication for valvular replacement to intervention.
Project Design:
The study is a prospective cohort study of patients with severe aortic stenosis referred for aortic valve replacement. All referrals for aortic valve replacement will be allocated to either "transcatheter aortic valve replacement (TAVR)/ surgical aortic valve replacement (SAVR) (standard of care)" or "deferred intervention" based on prespecified criteria. Patients with critical aortic stenosis as defined by an aortic valve area (AVA) <0.6 cm2 or a transvalvular mean gradient of >60 mmHg or a history of cardiac decompensation during the previous 3 months or clinical symptoms on minimal exertion (NYHA III) will be allocated to TAVR or SAVR. All other patients with severe aortic stenosis defined by an AVA <1.0 cm2 will be scheduled for a deferred intervention.
Condition or disease | Intervention/treatment |
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Aortic Valve Stenosis | Device: TAVR or SAVR |
Study Type : | Observational [Patient Registry] |
Actual Enrollment : | 71 participants |
Observational Model: | Cohort |
Time Perspective: | Prospective |
Target Follow-Up Duration: | 6 Months |
Official Title: | Morbidity and Mortality Due to Deferral of Aortic Valve Replacement in Patients With Severe Aortic Stenosis - a Collateral Effect of the SARS-CoV-2 Pandemic (AS DEFER) |
Actual Study Start Date : | March 20, 2020 |
Actual Primary Completion Date : | April 30, 2021 |
Actual Study Completion Date : | April 30, 2021 |

Group/Cohort | Intervention/treatment |
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TAVR/SAVR
Patients with critical aortic stenosis as defined by an AVA <0.6 cm2 or a transvalvular mean gradient of >60 mmHg or a history of cardiac decompensation during the previous 3 months or clinical symptoms on minimal exertion (NYHA III) will be allocated to transcatheter aortic valve replacement or surgical aortic valve replacement.
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Device: TAVR or SAVR
Patients with critical aortic stenosis as defined by an AVA <0.6 cm2 or a transvalvular mean gradient of >60 mmHg or a history of cardiac decompensation during the previous 3 months or clinical symptoms on minimal exertion (NYHA III) will be allocated to TAVR or SAVR. |
Deferred Intervention
Patients with severe but not critical aortic Stenosis will undergo deferred intervention.
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- Composite of all-cause mortality, disabling and non-disabling stroke, and hospitalization for heart failure [ Time Frame: Assessed at 6 months after indication/referral for aortic valve replacement. ]

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Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Sampling Method: | Non-Probability Sample |
Inclusion Criteria:
- Age ≥ 18 years
- Patients with severe AS defined by an AVA <1cm2 or AVA indexed to BSA of <0.6 cm2/m2, including low-flow severe aortic stenosis defined by SVI <35ml/m2.
Exclusion Criteria:
- Life expectancy <1 year irrespective of severe AS.
- Severe dementia defined as MMS-Test <16 points.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04333875
Switzerland | |
Department of Cardiology, Bern University Hospital | |
Bern, Switzerland, 3010 |
Principal Investigator: | Thomas Pilgrim, MD | University of Bern, Switzerland |
Responsible Party: | University Hospital Inselspital, Berne |
ClinicalTrials.gov Identifier: | NCT04333875 |
Other Study ID Numbers: |
2020-00672 |
First Posted: | April 3, 2020 Key Record Dates |
Last Update Posted: | March 14, 2023 |
Last Verified: | March 2023 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Undecided |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
Aortic Valve Stenosis Constriction, Pathologic Pathological Conditions, Anatomical Aortic Valve Disease |
Heart Valve Diseases Heart Diseases Cardiovascular Diseases Ventricular Outflow Obstruction |