**5. Diagnosis**

**4.4. Hemodynamic effect**

**Table 3.** Aortic dilatation pattern.

**Classification**

Shafer et al. [28] Type N (normal root)

108 Structural Insufficiency Anomalies in Cardiac Valves

>STJ

Fazel et al. [43] Cluster I

Verma et al. [41] Type 1

STJ: sinotubular junction

Ascending < sinuses

Aortic root alone

Dilatation of tubular ascending aorta primarily along convexity of aorta, with mildto-moderate root dilatation

Flow abnormalities, related to turbulent and helical flow patterns, as a result of the asymmetric movement of valve leaflets, may be a major contributor to aortic dilation in BAV. Even normally functioning BAVs may have abnormal transvalvular flow patterns, resulting in regional increases in wall shear stress [60, 61]. The asymmetric opening of even "clinically normal" BAV has been demonstrated. The orifice of the open BAV has been shown to be irregular and dome shaped due to the restricted motility of conjoined leaflets. This asymmetric and morphologically stenotic orifice leads to a nonaxial, turbulent transvalvular flow jet, which propagates eccentrically toward the wall of ascending aorta [61]. Restricted systolic conjoint cusp motion may cause flow deflection even if the BAV is normofunctional on echocardiographic evaluation. Systolic flow deflection toward the right, affecting the right anterolateral-ascending wall, has been demonstrated by magnetic resonance imaging (MRI) [62]. Abnormal cusp motions of BAV, including folding or wrinkling of the valve tissue and increased cusp doming during the cardiac cycle, may result in altered flow characteristics even when the cusps are not stenotic [63]. MRI studies have shown that RL BAV phenotype is associated with rightward flow deviation (flow jet directed toward the right anterior aortic wall, which is then propagated in a right-handed helical direction) and dilatation of tubular portion of the ascending aorta. Right anteriorly oriented flow jet may also result in larger aortic root dimensions and asymmetric dilatation of midascending tract [53]. However, RN BAV phenotype has been linked to the leftward deviation (flow jet directed toward left posterior aortic wall) and diffuse dilatation of the ascending aorta extending to the arch [64, 65]. The RN BAV phenotypes have shown more

Type A (ascending dilatation)

Type E (effaced roots)

Tubular portion and transverse arch

Isolated aortic-root involvement with normal tubular ascending aorta and arch dimensions

Cluster IV Aortic root and tubular portion with tapering across the transverse arc

Sinuses < STJ

Cluster III

Type 3

Ascending > sinuses

Tubular ascending aorta

Arch dilatation with involvement of tubular ascending aorta, with relative sparing of root

>STJ

alone

Type 2

Cluster II

severe hemodynamic flow abnormalities than the RL BAV phenotypes [65].

Most patients with BAV are unaware of the diagnosis until elderly because the symptoms and physical findings are usually absent for many years. Unless echocardiography is requested for other indications, the diagnosis is usually made at the time of an adverse cardiovascular outcome.

The systolic ejection murmur of the aortic stenosis, auscultated on the left side of the sternum, and the diastolic murmur of the aortic regurgitation, heard mainly on the apex, are highly valuable in the diagnosis. In the current area, transthoracic echocardiogram usually confirms the diagnosis of BAV disease. For the confirmation, the valve must be visualized in systole and diastole in the short axis view. The valve openings are fish-mouth shaped. Diastolic images can be misleading because the cusp fusion in the larger leaflet of a bicuspid valve may simulate a tri-leaflet valve in the closed position. It may be more difficult to make the diagnosis if there is an incomplete fusion between the cusps. The valve closure is usually eccentric and the leaflets show doming in the long axis views.

Aortic valve and ascending aorta surgery were performed in 29% of these patients [46]. On the other hand, patients with BAV-AR and root aneurysm have shown a higher risk of aortic

Bicuspid Aortic Valve

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http://dx.doi.org/10.5772/intechopen.76643

Aortic dissection occurs 9 times more often and at an average of 1 decade earlier among patients with BAV than those with TAV [63]. The patients with BAV and aortic aneurysm >4.5 cm have been found eight times more likely to undergo an aortic dissection [75]. The patients with BAV-AR have a tenfold higher risk of post-AVR aortic dissection than the patients with BAV-AS [76]. The aortic dissection rate in BAVs has been found to be 0.77% and

The aortic diameter at the baseline is also an important predictor of aortic dilatation. In children under 18 years old, ascending aorta z score has been shown to progress with time and an initial z score > 2 with the presence of AS has been accepted as a clinical marker for higher z scores in early adulthood [48]. The z scores of 4 or above, present in 13% of the patients under 18 years old, have been considered to reveal significant aortic dilation which predicts the subsequent aneurysm development [75] Relevantly, it has been shown that an aortic diameter of 4 cm or more at the baseline evaluation independently predicts the subsequent development of aneurysm. The incidence of aortic dissection in these patients during 16 years of followup was 3.1%, significantly higher than the general population [75]. Dissection rates in the patients with the aortic diameters of above 3.5, 4.5, and 5.5 cm are 8.5, 57.1, and 10%, respectively [77]. The aortic size larger than 4.5 cm or aortic cross-sectional area/height > 8–10 should

BAV types can predict the progression of aortic valve dysfunction or the development of aortic aneurysms [80]. The presence of a raphe has been associated with a higher prevalence of significant AS and AR, which increase the need for surgery. Despite the higher mortality in patients with BAV and raphe, raphe is not independently associated with increased all-cause mortality.

Beta-adrenergic blockers, angiotensin converting enzyme inhibitors, and angiotensin receptor blockers are the antihypertensive agents of choice. Beta-adrenergic blockers have the theoretical advantage of reducing aortic wall shear stress, whereas angiotensin receptor blockers have been shown to reduce the rate of aortic growth in patients with Marfan's syndrome [24].

During childhood, insertion of a prosthetic valve is suboptimal because of the continuing growth of the child. Fortunately, at this stage, the aortic valve is usually not calcified and valvuloplasty can successfully disrupt the commissural fusion and relieve obstruction. Valvuloplasty is the interventional strategy of choice in children and in some young adults

The studies about the various treatment modalities are continuing vigorously.

the frequency of aortic dissection is 0.1% per patient's year of follow-up [45].

be considered for concurrent aortic valve and ascending aorta surgery [78, 79].

dissection and rupture [74].

**7. Treatment strategies**

**7.1. Medical treatment**

**7.2. Intervention**

with BAV and AS [70].

It may be difficult to make the diagnosis in the obese patients due to the nonqualified, blurred vision. In such cases, the diagnosis can be established by means of transoesaphagial echocardiography (TEE) or cardiac MRI or computerized tomography (CT) imaging.
