**7. Aortic regurgitation**

BAV has become the most common cause of isolated primary aortic regurgitation in the developed world. There may be mixed aortic regurgitation and stenosis; however, in approximately 5–10% of patients will have moderate-severe isolated primary aortic regurgitation [13]. Pathophysiology for aortic regurgitation in BAV usually includes leaflet deformities (size variation, prolapse, fenestrations, thickening or immobility), aortic root dilation (root phenotype), endocarditis or aortic dissection.

Patients with BAV syndrome are a younger population and therefore the long-term durability of surgical procedures and minimization of associated complications are critical outcome goals [4]. Decisions regarding the therapeutic interventions are based on aortic valve phenotype and ascending aortic/root phenotype (**Figure 1**).

Valve choice is an important decision. Currently, fewer patients are willing to alter their lifestyle or take the anticoagulation required for mechanical prosthesis, especially with TAVR options as a bridge. Equally important, consideration of therapeutic options and anticoagulation must be assessed for BAV women of childbearing age [4]. For these reasons a better understanding of the optimal surgical technique for BAV ascending/root aortic aneurysm disease is critical.

The **Figure 1** delineates the anatomic and pathophysiologic criteria utilized for decision making.

#### **7.1 Aortic insufficiency (AI) phenotype**

Indications for aortic valve intervention for AI and AS are delineated in the 2020 ACC/AHA Guideline [47]. Surgical aortic valve replacement currently includes either bioprosthetic or mechanical valve [4, 10].

There has also been a trend toward more reparative surgical approach for bicuspid aortic insufficiency. Primary cusp repair for patients with appropriate cusp pathology, although technically more complex than prosthetic aortic valve replacement, is becoming an attractive option as it may reduce the risk of Major Adverse Valve-Related Event (MAVRE) [4, 48]. Long-term outcome and follow-up studies will be important to monitor these patients.

#### **7.2 Aortic insufficiency with aortic phenotype**

For BAV syndrome patients with Aortic Valve Insufficiency phenotype and aortic root phenotype with sinus of Valsalva (SOV) measuring ≥45 mm, the **Figure 1** delineates the therapeutic options. The mechanical Bentall procedure has been a gold standard for multiple root pathologies with low morbidity and mortality [4, 49]. However, mechanical valves do not always carry 100% freedom from reoperation or a survival similar to age-matched controls [4]. Good long-term results for patients with a biologic composite root have been shown in a recent study and a meta-analysis of the Bentall procedure and revealed an annual linearized rate for late mortality of 2.02%, reoperation of 0.46%, bleeding of 0.64%, thromboembolic events of 0.77%, and MAVRE of 2.66% [4, 50]. This procedure can be performed for BAV aortic root and valvular pathologies with good long-term results [4]. A recent study in BAV patients undergoing Bentall procedure revealed a 5 and 10-year survival of 93% and 89% respectively, with freedom from reoperation of 100% and 1.9% stroke rate at 6 years [4, 51].

For patients with BAV aortic valve insufficiency phenotype and aortic root phenotype with a valve that is repairable, a valve sparing root replacement (VSRR) can be employed [4, 52, 53]. A study by de Kerchove reported 98.3% 5-year survival and 100% freedom from reoperation at 6 years in BAV patients undergoing VSRR [54]. Similarly, Kari reported 99% survival and 6-year 90% freedom from reoperation for BAV VSRR [55]. DeNino et al. demonstrated a lower aortic valve gradient and similar postoperative complication rates in the VSRR group compared to bioprosthetic valve conduit [56]. A study by Vallabhajosyula et al., in the isolated BAV insufficiency subpopulation noted a 5-year freedom from reoperation and survival for Bentall

### *Bicuspid Aortic Valve: Current Therapeutic Strategies DOI: http://dx.doi.org/10.5772/intechopen.113315*

and VSRR at 98% and 100% versus 100% and 98% respectively [53]. These studies support the findings that primary repair with VSRR can be selectively utilized to treat BAV AI with root aneurysm [52–56]. This decision should be weighed against the risk of recurrent AI. The VSRR patients have been shown to have significantly lower mortality, stroke, and MAVRE compared to mechanical Bentall [4]. The results of recent studies may be utilized to inform young BAV patients interested in biologic conduit or repair options, especially those averse to taking anticoagulation and open to transcatheter valve options in the future. Long-term 15-to-20-year data will be important to better understand the role of biologic versus mechanical valves in BAV aortic root complex focused procedures. In patients with a non-repairable valve, Bentall procedure remains the standard of care [4].
