The AVIATOR registry: the importance of evaluating long-term patient outcomes

Being a technically gifted surgeon is not enough to make you a good aortic valve repair surgeon. An additional requirement is the long-term evaluation of the treatment and comparison of your results to other surgeons. The AVIATOR registry, outlined below, enables surgeons to evaluate their results and fulfill this requirement.

Over the past two decades, aortic valve repair has evolved as a treatment strategy in patients with aortic regurgitation (AR) with or without aortic dilatation. The first attempts go back to the early sixties and two important surgical procedures—remodeling and reimplantation—appeared in the late 1980s and early 1990s, which gave rise to new tools for the treatment of complex disorders of the aortic valve and root (1). In the current era, considerable variety in repair techniques exist: reimplantation with straight or sinus tube grafts, remodeling techniques with or without additional annuloplasty with a suture or ring, usage of various patch materials, different commissural orientations after bicuspid aortic valve repair and the use of systematic measurement tools of effective height.

Aortic valve repair is usually performed in specialized centers as these procedures require a steady number of cases to maintain expertise and skills, noting that the incidence of potential patients is low. Most publications originate from single centers and report only mid-term results (2). Not all valves are good candidates for aortic valve repair and additional treatment options are mechanical valve replacement, the Ross procedure and aortic wrapping [e.g., Personalized External Aortic Root Support (PEARS)].

To help surgeons and patients with choosing the best treatment option, ideally long-term outcome of lots of patients after different therapies should be compared. To achieve this, uniform outcome evaluation measurements, multi-center data and patient-centered information is needed. This will provide a firm base for a coherent discourse for cardiologist and cardiothoracic surgeons treating and informing these patients.

With this in mind, the Aortic Valve (AV) Insufficiency and ascending aorta Aneurysm InternATiOnal Registry (AVIATOR) was established. The AVIATOR community is one of the Valve Research Networks (VRN) of the Heart Valve Society (HVS) (3). In the AVIATOR registry, a longitudinal disease specific patient cohort is followed, meaning all patients with isolated aortic valve insufficiency (including congenital mixed aortic valve disease) and/or ascending aorta aneurysm (including root and/or supra coronary aorta and aortic dissection) are eligible. This is irrespective of whether patients undergo aortic valve repair or replacement. The registry is open to any center taking care of these patients, thus not for the highly specialized centers only. Participation is free, at least one person of the team needs to be a member of the HVS. All information to join is available on: http://heartvalvesociety.org/AVIATOR.

The ultimate goal is to embrace the complete disease trajectory of AR from diagnosis till death by clinical and echocardiographic follow-up once the diagnosis has been made. The adult surgical AVIATOR database is established and has been enrolling patients since August 2013. AVIATOR-kids (pediatric surgery) is in progress and enrollment will follow in the near future. The same holds for the AVIATOR medical registry, which will enable the study of the natural history of AR and evaluation of the guidelines.

The AVIATOR registry collects detailed information of perioperative cusp analysis and cusp repair strategy. Furthermore, the intention to repair the valve is asked at two points in time: preoperatively, based on echocardiography and preoperatively, after cusp analysis. In combination with information on long-term durability of the repair, this could shed light on which patients are good candidates for repair and which are not and will thus enable tailor-made treatment strategies. Participating centers are asked to update clinical follow-up (bi-)annually. Obviously, it is not just survival, but the relief of symptoms, avoidance of long-term disability and a sense of well-being that are likely to be the most important and highly valued outcomes for patients. At present, the AVIATOR registry embraces the uniform outcome evaluation measures according to the guidelines for reporting mortality and morbidity after cardiac valve interventions by Akins et al. (4). The addition of quality of life assessment to the registry will be an important goal for the future. The AVIATOR registry is a voluntary registry and leans on the effort participants are willing to put in. Data completeness can be a risk and will be the main focus the coming years. By hiring a full-time data manager, the AVIATOR initiative will professionalize further.

The AVIATOR registry originated in Europe and especially European centers are enrolling patients at this stage. They are responsible for the inclusion of 5,348 (89.2%) patients, followed by North America with 457 (9.5%) patients, Africa 42 (0.8%) patients and Asia 16 (0.5%) patients. Valve repair is the dominant operation with 88% versus 12% replacements. The reconstructive surgery includes isolated valve repair in 27%, partial root or tubular aorta replacement plus valve repair in 23% and valve-sparing root replacements in 50%. Replacements include isolated valve replacement in 22%, tubular aorta plus aortic valve replacement in 19% and root plus valve replacement (Bentall) in 59%. Most of the expert centers on aortic valve repair are including all their patients in the AVIATOR registry.

The AVIATOR initiative is a unique effort in sharing data worldwide. It has grown exponentially the last 5 years from its birth in 2013 till now. The first descriptive analysis of the AVIATOR population shows the variation of patients and reveals potential biases within the registry (e.g., repair versus replacement, high versus low volume centers and European countries versus other regions). The AVIATOR data-platform catalyzes new initiatives within the HVS. To evaluate prosthetic aortic valve replacement in patient with AR or stenosis a new initiative has arisen: the LEOPARD registry.

By combining surgical experience from multiple centers and applying uniform definitions of echo and outcome parameters, it should become possible to provide a solid evidence base for tailored treatment in the individual patient with aortic valve regurgitation and/or dilatation of the ascending aorta. Long-term commitment of surgeons into clinical evaluation is key to provide solid medical evidence and to deliver the best treatment to our patients according to current medical knowledge.