Aortic Valve Replacement Versus Conservative Treatment in Asymptomatic Severe Aortic Stenosis (AVATAR)
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ClinicalTrials.gov Identifier: NCT02436655 |
Recruitment Status :
Completed
First Posted : May 7, 2015
Last Update Posted : January 12, 2022
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Condition or disease | Intervention/treatment | Phase |
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Aortic Stenosis | Procedure: surgical aortic valve replacement | Not Applicable |
Aortic valve replacement (AVR) therapy is obvious choice in symptomatic severe aortic stenosis (AS) patients, because it improves symptoms, LV function and survival. Therefore, the accurate diagnosis of the disease, determination of its severity and precise evaluation of patients' clinical status is essential. However, the treatment decisions and indication for AVR in asymptomatic patients with severe AS and normal left ventricular ejection fraction (LV EF) are vague and the subject of ongoing debate. The most recent European and American guidelines have class I indication for AVR in asymptomatic severe AS patients with normal LV EF only in patients already scheduled for other cardiac surgery (for example by-pass surgery). In the case of symptom positive stress test American and European guideline differs, with European guidelines having class I indication and American guidelines only IIb indication. In all those cases of asymptomatic severe AS patients with normal LV EF the level of evidence is C, in other words there are no randomized trials. The consequence is that the decisions are made individually, patient by patient, and for this reason a patient with identical echocardiographic/clinical characteristics might be operated in USA but not in Europe (or any other part in the world), and vice-versa.
With the experience that has accumulated so far, there are retrospective and observational data that elective AVR might lead to favorable outcome compared to late (after symptom onset) surgery. This may especially come to attention with the understanding that annual risk of sudden cardiac death in asymptomatic severe AS patients with normal LV EF might be very similar or even a bit higher than operative mortality in experienced cardiac surgery centers.
Nevertheless, the majority of cardiologist worldwide are reluctant to send their asymptomatic patient with isolated severe AS and normal LV EF to AVR, and it will probably stay like that till randomized trials give us an answer whether elective AVR is beneficial.
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 157 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | Aortic Valve Replacement Versus Conservative Treatment in Asymptomatic Severe Aortic Stenosis: (AVATAR Trial): A Multicentre Randomized Controlled Trial |
Actual Study Start Date : | June 2015 |
Actual Primary Completion Date : | May 2021 |
Actual Study Completion Date : | May 2021 |

Arm | Intervention/treatment |
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No Intervention: conventional drug treatment
conservative treatment and watchful waiting till symptom onset (then aortic valve replacement). Other indications for aortic valve replacement include reduced left ventricular systolic function
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Active Comparator: elective aortic valve replacement
elective aortic valve surgery (replacement) within 4 weeks after randomization
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Procedure: surgical aortic valve replacement
open heart aortic valve replacement |
- all cause death, Major Adverse Cardiac Event (MACE) including: ( Acute Myocardial Infarction - AMI, Stroke - CVI, unplanned hospitalization for Heart failure (HF) needing intravenous treatment [ Time Frame: 36 months ]
- all cause death, Major Adverse Cardiac Event (MACE) including: ( Acute Myocardial Infarction - AMI, Stroke - CVI, unplanned hospitalization for Heart failure (HF) needing intravenous treatment [ Time Frame: 5 years ]
- in-hospital and 30 days operative mortality in operated patients in both groups [ Time Frame: 30 days ]
- repeat aortic valve surgery in operated patients in both groups [ Time Frame: 5 years ]
- major bleeding according to consensus report from the Bleeding Academic Research Consortium [ Time Frame: 5 years ]
- thromboembolic complications based on clinical symptoms, signs and imaging studies [ Time Frame: 5 years ]
- repeated major adverse cardiovascular events [ Time Frame: 5 years ]
- all-cause death + heart failure hospitalization [ Time Frame: 5 years ]

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Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- men and women of any ethnic origin aged ≥18 years
- Written informed consent
- V max across the aortic valve > 4m/s or Pmean ≥ 40mmHg and AVA ≤ 1cm2 or AVAi ≤ 0.6cm2/m2 at rest
- Without reported symptoms
- Society of Thoracic Surgeons (STS) score < 8%
Exclusion Criteria:
- Participation in another clinical trial within 30 days prior randomization
- Pregnant or nursing women
- Mental condition rendering the patient unable to understand the nature, scope and possible consequences of the study or to follow the protocol
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Positive stress-test defined as:
- Anginal chest pain during testing
- Syncope, dizziness during testing
- Decrease in systolic blood pressure during exercise ≥ 20mmHg
- Malignant arrhythmia during exercise testing (VT or VF)
- Left ventricular ejection fraction < 50% at rest
- Very severe AS (defined as Vmax > 5.5 m/s at rest)
- Significant disease of other valves (Mitral stenosis with Pmean > 5mg, or any significant regurgitation ≥ 3+
- Recent AMI (< 1 year)
- Need for additional by-pass surgery or for aortic root replacement (i.e Bentall) or ascending aorta in asymptomatic patients undergoing AVR
- Previous by-pass surgery
- Previous any heart valve surgery
- Impaired renal function, i.e. creatinine >200 µmol/L or glomerular filtration rate < 30 mL/min/1.73 m2
- Significant pulmonary hypertension at rest (PASP > 50mmHg)
- Uncontrolled hypertension at rest (systolic >180 mmHg and diastolic >100 mmHg)
- Significant co-morbidity with reduced life expectance (< 3 years)
- Uncontrolled Diabetes Mellitus (HbA1C > 9 %)
- Significant COPD (FEV1 < 70% of predicted value)
- Permanent or paroxysmal atrial fibrillation

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): NCT02436655
Belgium | |
Cardiovascular Center Aalst | |
Aalst, Belgium, 9320 | |
Croatia | |
University Clinical Center "Rebro" | |
Zagreb, Croatia | |
University Clinical Center ''Sestre milosrdnice'' | |
Zagreb, Croatia | |
Czechia | |
University Hospital Brno | |
Brno, Czechia, 62500 | |
Institute for Clinical and Experimental Medicine (IKEM) | |
Prague, Czechia, 14021 | |
France | |
Hôpital Cardiologique de Haut Lévèque | |
Pessac, France, 33604 | |
Ireland | |
University Hospital Galway | |
Galway, Ireland | |
Italy | |
Città della Salute e della Scienza di Torino | |
Turin, Piedmont, Italy | |
Lithuania | |
Vilnius University Hospital Santariskiu klinikos | |
Vilnius, Lithuania, 08661 | |
Poland | |
Medical University of Silesia | |
Katowice, Poland, 40005 | |
Serbia | |
Cardiovascular Center 'Dedinje" | |
Belgrade, Serbia, 11000 | |
CCSerbia | |
Belgrade, Serbia, 11000 | |
University Clinical Centre Zvezdara | |
Belgrade, Serbia, 11000 | |
Insitute for Cardiovascular Diseases "Sremska Kamenica" | |
Novi Sad, Serbia |
Principal Investigator: | Marko Banovic, MD, PhD, FESC, FACC | Cardiology Department, University Clinical Centre of Serbia | |
Principal Investigator: | Svetozar Putnik, MD, PhD | Cardiac Surgery Department, University Clinical Centre of Serbia |
Documents provided by Marko Banovic, Clinical Centre of Serbia:
Other Publications:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: | Marko Banovic, MD PhD, FESC, FACC, Assistant Professor, Clinical Centre of Serbia |
ClinicalTrials.gov Identifier: | NCT02436655 |
Other Study ID Numbers: |
FWA00011929 |
First Posted: | May 7, 2015 Key Record Dates |
Last Update Posted: | January 12, 2022 |
Last Verified: | December 2021 |
aortic stenosis normal ejection fraction asymptomatic |
Aortic Valve Stenosis Constriction, Pathologic Pathological Conditions, Anatomical Aortic Valve Disease |
Heart Valve Diseases Heart Diseases Cardiovascular Diseases Ventricular Outflow Obstruction |