Surgical threshold for bicuspid aortic valve aneurysm: a case for individual decision-making

Abstract

The bicuspid aortic valve (BAV) affects 1-2% of the population and may be associated with important valvular disease and an increased risk of aortic root and/or ascending aortic aneurysm and dissection. BAV aortic aneurysm and dissection occur earlier in life than when these disorders are associated with a tricuspid aortic valve (TAV). Alterations in the aortic media and differences in aortic elastic properties and wall stress also accompany BAV aortopathy. With appropriate follow-up and timely surgery, population studies have documented a survival rate for patients with BAV no different from age-matched controls. Guidelines have previously recommended prophylactic aortic surgery at a smaller aortic aneurysm size for patients with BAV compared with aneurysms in patients with a TAV. Recent guidelines have presented differing indications regarding the appropriate timing of prophylactic surgery for BAV aneurysms, giving the recommendation for surgery when the aortic root and/or ascending aortic exceeds 5.5 cm (unless certain factors are present), the same size for which TAV-associated aortic aneurysm surgery is recommended. We review the pathophysiology of BAV aortopathy, the clinical history of BAV ascending aortic disease, areas of uncertainty and make a case for a patient-centered, individualised decision regarding the optimal timing of aortic aneurysm surgery in BAV disease.

Year in review

“…More conservative approaches to resection consider that not all patients are at high risk of aortic complications and that hemodynamic and other risk factors may be at play. Over the past 18 months, original research publications and expert perspective contributions have shown a growing appreciation for the individual variability in the progression of the disease and the possible influence of hemodynamic determinants of the disease(17–29). Experts in this area have assembled into working groups, such as the International BAV Consortium (BAVCon), to define specific gaps in knowledge and develop collaborative research platforms to address these key issues(9, 30).…”

“…Many experts in the area of BAV aortopathy agree that the discovery and implementation of novel aortic risk markers will be critical for the development of consistent guidelines for optimal management of BAV patients with aortic dilatation(2, 29). Aortic hemodynamics are emerging as an important biomarker toward this goal.…”

Managing Thoracic Aortic Aneurysm in Patients with Bicuspid Aortic Valve Based on Aortic Root-Involvement

“…Studies have suggested a correlation between BAV phenotype and the valvular complications that develop. The overall evidence suggests that R-N BAV phenotypes have the greatest incidence of AS in both children and adults (Fernandes et al, 2004, 2007; Huang and Le Tan, 2014; Adamo and Braverman, 2015). In pediatric patients, those with the R-N BAV phenotype were more likely to have AI progression (Fernandes et al, 2004).…”

Evolution of Precision Medicine and Surgical Strategies for Bicuspid Aortic Valve-Associated Aortopathy

“…It is now believed that these conventional hemodynamic factors alone do not reflect the impact on the aortic wall due to a malformed valve (Girdauskas et al, 2011; Sievers and Sievers, 2011; Atkins and Sucosky, 2014; Della Corte et al, 2014b; Adamo and Braverman, 2015; Michelena et al, 2015; Moon, 2015). These findings imply that the development of bicuspid aortopathy is not primarily driven by a genetic predisposition.…”

“…Most patients will present with maximal dilatation of the tubular mid-ascending aorta, specifically at the greater curvature, with the aortic root and proximal arch being affected to varying degrees. Thus, resection strategies can vary greatly (Fedak et al, 2005; Della Corte et al, 2014a; Fedak and Verma, 2014; Adamo and Braverman, 2015; Moon, 2015; Sundt, 2015). In addition to deciding when to intervene in replacing the aorta in bicuspid aortopathy, assessing what to resect also poses a clinical dilemma (Fedak and Verma, 2014; Sundt, 2015).…”