Bicuspid aortic valve: General management in adults

INTRODUCTION — The bicuspid aortic valve condition is a valvulo-aortopathy (affecting both the aortic valve and the thoracic aorta) [1]. Adults with bicuspid aortic valves commonly develop aortic valve dysfunction and disease of the ascending aorta and therefore require surveillance and appropriate management of these conditions. The management of bicuspid aortic valve disease in adults includes surveillance, timely intervention for valve disease and aortopathy, treatment of hypertension, measures to address the risk of infective endocarditis, counseling patients on physical activity, and management prior to and during pregnancy. General noninterventional management for adults with bicuspid aortic valve will be discussed here.

Other aspects of management and diagnosis of bicuspid aortic valve in adults are discussed separately:

●(See "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults".)

●(See "Bicuspid aortic valve: Management during pregnancy".)

●(See "Clinical manifestations and diagnosis of bicuspid aortic valve in adults".)

Bicuspid aortic valve in children is discussed separately:

●(See "Valvar aortic stenosis in children" and "Subvalvar aortic stenosis (subaortic stenosis)" and "Aortic regurgitation in children".)

SURVEILLANCE — To enable timely intervention, all patients with bicuspid aortic valves should be monitored for progressive aortic valve dysfunction (stenosis and/or regurgitation) as well as for thoracic aortic dilation given the risk of aneurysm formation and aortic dissection.

How frequently to monitor — Echocardiography should be performed at intervals based upon the lesion requiring greatest frequency of surveillance among aortic stenosis, aortic regurgitation, and dilation of the aorta. Development of significant aortic stenosis is much more common than development of significant aortic regurgitation. The rate of aortic growth in bicuspid aortic valve patients is variable, ranging from 0.2 to 2.3 mm/year [2-5], depending upon patient characteristics [6,7]. Higher rates of growth are observed in older adults and those with larger aneurysms [6,8,9].

If the thoracic aorta cannot be adequately assessed by echocardiography, these are assessed by magnetic resonance imaging (MRI) or computed tomography (CT), as described below. (See 'How to monitor' below.)

The following recommendations for surveillance and management for aortic stenosis, aortic regurgitation, and aortic dilation are in broad agreement with the 2022 American College of Cardiology/American Heart Association (ACC/AHA) guideline for the diagnosis and management of aortic disease, the 2020 ACC/AHA valve guidelines, the 2018 ACC/AHA adult congenital heart disease guidelines, the 2015 ACC/AHA scientific statement on eligibility and disqualification recommendations for competitive athletes with cardiovascular abnormalities, and the 2018 American Association for Thoracic Surgery bicuspid aortic valve-related aortopathy guidelines [10-14]:

●For adults with aortic stenosis:

•With severe aortic stenosis (defined as peak jet velocity ≥4 m/sec, mean gradient >40 mmHg, or valve area <1.0 cm²), we suggest Doppler echocardiography every 6 to 12 months.

•With moderate aortic stenosis (defined as peak jet velocity 3 to 3.9 m/sec, mean gradient 25 to 40 mmHg, or valve area 1.0 to 1.5 cm²), we suggest Doppler echocardiography every one to two years.

•With mild aortic stenosis (defined as peak jet velocity 2.0 to 2.9 m/sec, mean gradient <25 mmHg, or valve area >1.5 cm²), we suggest Doppler echocardiography every three to five years.

●For adults with aortic regurgitation:

•With severe aortic regurgitation, we suggest Doppler echocardiography every 6 to 12 months (more frequently if the left ventricle is dilating).

•With moderate aortic regurgitation, we suggest Doppler echocardiography every one to two years.

•With mild aortic regurgitation, we suggest Doppler echocardiography every three to five years.

●For adults with bicuspid aortic valve, serial evaluation of the size and morphology of the aortic sinuses and ascending aorta by echocardiography (generally transthoracic echocardiography [TTE]), MRI, or CT) is recommended, with the examination interval determined by the aortic size, the rate of progression of aortic dilation, and other risk factors, including family history [13-15]. When the aortic diameter is approaching a surgical threshold, more frequent imaging is reasonable.

•If thoracic aortic diameters are normal, the thoracic aorta should be reassessed every three to five years [15].

•If the aortic root or tubular ascending aorta measures 4.0 to 4.9 cm, the thoracic aorta should be reimaged at 12 months. After this initial reimaging, if the aortic root or tubular ascending aorta measures 4.0 to 4.4 cm and remains stable, then surveillance imaging is continued every two or three years. If the aortic diameter is 4.5 to 4.9 cm and remains stable, then annual imaging is recommended.

•If the aortic root or ascending aorta diameter is 5.0 to 5.4 cm or if there is a rapid rate of change in aortic diameter (ie, >3 mm/year), then reassessment of the aortic root and ascending aorta size should be performed more frequently [15]. (See "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults", section on 'Approach to identifying candidates for aortic surgery'.)

●For competitive athletes with bicuspid aortic valve and aortic dilation >40 mm, annual monitoring of the aorta with echocardiography or cardiovascular magnetic resonance (CMR) imaging is recommended [11].

●If a patient requires cardiac surgery (eg, for aortic valve dysfunction) and has an aortic root or ascending aortic measurement of 40 to 44 mm on TTE, preoperative assessment of the thoracic aorta by CMR or CT is recommended to determine if concomitant aortic surgery is indicated [15].

Earlier reevaluation (beyond the surveillance regimen described above) is indicated for changes in symptoms or examination and for hemodynamic assessment related to pregnancy (see "Bicuspid aortic valve: Management during pregnancy"). Of note, although surveillance of the aorta is based upon aortic diameter, other factors (eg, genetic factors, hemodynamic effects) likely contribute to the risk of acute aortic events (eg, aortic dissection and aortic rupture) [6].

As discussed separately, first-degree relatives of patients with bicuspid aortic valve should be evaluated for the presence of bicuspid aortic valve and thoracic aortic disease. (See "Clinical manifestations and diagnosis of bicuspid aortic valve in adults", section on 'Screening'.)

How to monitor — Aortic valve disease surveillance is performed by clinical assessment (of symptoms and signs) and imaging of the ascending aorta and aortic arch. The maximum end-diastolic diameter perpendicular to aortic flow is measured in mm for each segment along the thoracic aorta including the aortic root (sinus to sinus or sinus to commissure), sinotubular junction, ascending aorta, aortic arch, and descending thoracic aorta [14-16].

As discussed separately, evaluation for coarctation of the aorta is also warranted; if coarctation is detected, screening for cerebral aneurysms is indicated. (See "Clinical manifestations and diagnosis of bicuspid aortic valve in adults", section on 'Coarctation of the aorta'.)

Imaging modalities — TTE is used for monitoring the thoracic aorta if image quality is adequate. There are many different phenotypes of aortic enlargement with bicuspid aortic valve (bicuspid valve "aortopathy") [1,17]. The most common site of aortic dilation is at the ascending aorta, and monitoring by transthoracic echocardiography is often inadequate at this level unless high right parasternal views are obtained. (See "Clinical manifestations and diagnosis of bicuspid aortic valve in adults", section on 'Aortic dilation and aortic dissection' and "Echocardiographic evaluation of the thoracic and proximal abdominal aorta".)

If any segment of the thoracic aorta is not adequately visualized by TTE, any segment measures ≥45 mm, or aortic coarctation cannot be ruled out, then the entire thoracic aorta should be imaged by CMR (with no contrast generally required) or CT (both electrocardiogram [ECG]-gated) [14,15]. If TTE measurements are consistent with CMR or CT measurements, then interval aortic measurement may be performed by TTE with repeat CMR or CT every three years to reconfirm agreement [15]. If TTE and CMR or CT measurements are discordant, then CMR or CT should be used for interval aortic measurements. In the interest of reducing radiation exposure, for adults <50 years old, CMR is preferred if feasible.

The maximum diameter of an asymmetric aortic root at the sinuses of Valsalva is commonly underestimated in the TTE parasternal long-axis view, so it is important to measure this diameter also in the parasternal short-axis view or to proceed directly to CMR or CT imaging if root dilation is suspected [15,16].

How to measure — Measurement conventions differ among imaging modalities:

On echocardiographic images, a leading-edge to leading-edge measurement is used, since normative echocardiography data for the aortic root (except for the aortic annulus) were developed using the leading-edge to leading-edge technique [14-16,18]. However, the aortic annulus at the hinge points of the aortic valve leaflets is measured using the inner edge to inner edge [18]. (See "Echocardiographic evaluation of the thoracic and proximal abdominal aorta".)

On CMR or contrast CT images, we favor using the external (outer to outer) diameter. It is important to ensure that a consistent measurement technique is used, particularly given the lack of consensus on whether to use the external or internal diameters for CMR and CT images [15,16]. In patients requiring serial imaging, CMR is preferred to avoid repeated radiation exposure. Determination of aorta size by CMR generally does not require exogeneous gadolinium contrast agent administration. In patients with impaired renal function, the risk of iodinated intravenous contrast for contrast CT and the risk of gadolinium contrast should be considered.

Comparison — After aortic measurements are made, comparison is made with normal reference values as well as prior studies (most recent as well as earliest) using the same imaging modality by a clinician with expertise in that imaging technique [14-16]. Some experts use nomograms to assess how an individual's aortic dimensions compare with those in normal subjects with the same age and body size (figure 1 and figure 2). When identifying rapid aortic growth (ie, >3 mm/year), it is important to document aortic size on repeated measurements using the same imaging technique at the same aortic level with side-by-side comparison by a clinician with expertise in that imaging modality [14,15,19,20]. Comparison with the earliest prior image is important to detect gradual growth that can be may be missed when comparing only recent images [15].

INTERVENTION — Indications for intervention for aortic valve disease (stenosis or regurgitation) and for aortopathy associated with bicuspid aortic valve are discussed separately. (See "Bicuspid aortic valve: Intervention for valve disease or aortopathy in adults".)

PHARMACOLOGIC THERAPY — The role of drug therapy in patients with bicuspid aortic valve is limited, as evidence of efficacy is lacking [12,13,19]. No drug has been found to alter the natural history of bicuspid aortic valve disease or aortic stenosis more generally. (See "Medical management of asymptomatic aortic stenosis in adults", section on 'Prevention of disease progression'.)

While no drug has been shown to improve outcomes in patients with bicuspid aortic valve (including those with dilated aortic roots and/or aortic valve disease), hypertension, when present, should be treated according to standard guidelines [12,13,19]. (See "Overview of hypertension in adults".)

For patients with bicuspid aortic valve, chronic aortic regurgitation, and systemic hypertension (systolic blood pressure >140 mmHg), vasodilator therapy (such as angiotensin converting enzyme inhibitors, angiotensin II receptor blockers [ARBs], or dihydropyridine calcium channel blockers) are favored since they may reduce systolic blood pressure in this setting. Beta blocker therapy may be less effective in the setting of severe aortic regurgitation since reduction in heart rate and the associated increase in stroke volume may contribute to elevated systolic pressure and may contribute to an increase in regurgitant volume. (See "Natural history and management of chronic aortic regurgitation in adults", section on 'Pharmacologic therapy'.)

For patients with bicuspid aortic valve and dilated aortic root or ascending aorta without hypertension, there are no pharmacologic therapies proven to lessen aortic dilation or lessen the risk of aortic dissection or rupture. Some clinicians use beta blockers in this setting based upon the theoretical benefit and likely minimal risk. Beta blockers have a conceptual advantage in reducing the aortic wall stress which might reduce the rate of progression, but there are no outcomes data in this population to provide guidance [13]. The 2022 American College of Cardiology/American Heart Association (ACC/AHA) guideline for the diagnosis and management of aortic disease [14] and the 2020 ACC/AHA valve guidelines do not recommend any pharmacologic treatment in the absence of another indication, such as hypertension [13]. By contrast, the 2017 European Society of Cardiology guideline notes that use of beta blocker or losartan in patients with bicuspid aortic valve and aortic root and/or ascending aorta dilation is common clinical practice, although evidence to support this approach is lacking [21]. (See "Management of thoracic aortic aneurysm in adults", section on 'Antihypertensive therapies'.)

While some studies have found alterations in transforming growth factor-beta (TGF-beta) signaling in the aortas of patients with bicuspid aortic valve [22,23], evidence is lacking as to whether pharmacologic therapy directed against this signaling pathway (such as ARB drugs) can alter the risk of aortic aneurysm in patients with bicuspid aortic valve disease.

Since fluroquinolones have been linked to an increased risk of aortic dissection and aneurysm rupture, it is recommended that these drugs be avoided when possible in patients with bicuspid aortic valve and aortic aneurysm. As noted in US Food and Drug Administration labeling for these drugs, in patients with known aortic aneurysm or at increased risk for aortic aneurysm, fluoroquinolone use is reserved only for settings in which no alternative antibacterial treatment is available [24]. (See "Management of thoracic aortic aneurysm in adults", section on 'Avoidance of fluoroquinolones'.)

ENDOCARDITIS PREVENTION — Although the patient with bicuspid aortic valve is at risk for endocarditis, antibiotic prophylaxis is not recommended for isolated bicuspid aortic valve [13,25-27]. Individuals with bicuspid aortic valve should receive education about the risk of endocarditis and means of reducing the risk, including good dental care and oral health practices, awareness of symptoms of infection (including symptoms suggesting endocarditis, such as unexplained fevers, chills, and night sweats), and the importance of prompt reporting of symptoms of concern to health care providers. (See "Prevention of endocarditis: Antibiotic prophylaxis and other measures" and "Clinical manifestations and diagnosis of bicuspid aortic valve in adults", section on 'Infective endocarditis'.)

Individuals with bicuspid aortic valves are at increased risk of infective endocarditis compared with the general population and have a higher incidence of perivalvular abscess compared with those with tricuspid aortic valves [17,28]. In a community cohort from Olmstead county, the incidence of infective endocarditis (definite and possible) in individuals with a bicuspid aortic valve was estimated to be 10 per 10,000 patient-years, resulting in an age-adjusted relative risk of endocarditis for those with bicuspid aortic valve of 17 compared with that of the general population [29]. A meta-analysis of eight longitudinal cohort studies of infective endocarditis incidence included 5351 individuals with a bicuspid aortic valve [30]. During follow-up, 184 patients with bicuspid aortic valve developed infective endocarditis, with an incidence of 48 per 10,000 patient years (95% CI 22-74) and a 12-fold (95% CI 5-27) increased risk compared with the general population. The reported lifetime incidence of infective endocarditis in individuals with bicuspid aortic valve is 2 to 5 percent [31].

PHYSICAL ACTIVITY AND EXERCISE — Recommendations about exercise and physical activity for individuals with a bicuspid aortic valve are tailored to the type and severity of valve disease present (aortic stenosis or aortic regurgitation) and the presence of a dilated aortic root or ascending aorta. Guidelines for physical activity in patients with aortic stenosis and aortic regurgitation are discussed separately [11]. (See "Medical management of asymptomatic aortic stenosis in adults", section on 'Physical activity and exercise' and "Natural history and management of chronic aortic regurgitation in adults", section on 'Recommendations for physical activity and exercise'.)

Because certain physical activities lead to increases in blood pressure and aortic wall stress, lifestyle modification is necessary when significant aortic dilation is associated with bicuspid aortic valve disease. The 2015 American Heart Association/American College of Cardiology guidelines for competitive athletes with cardiovascular abnormalities provide exercise and sports participation recommendations for athletes with bicuspid aortic valve and aortic dilation [11]. These statements are starting points for the discussion of participation in various sports for the competitive athlete with a bicuspid aortic valve (figure 3 and table 1):

●Athletes with bicuspid aortic valve can participate in all competitive athletics if the aortic root and ascending aorta are not dilated (ie, z-score <2, <2 standard deviations from the mean, or <40 mm). The function of the bicuspid aortic valve (whether stenotic or regurgitant) is also important in determining participation recommendations.

●Adult athletes with a bicuspid aortic valve and a mild to moderately dilated aorta (z-score 2 to 3.5, or aortic root or ascending aortic diameters measuring 40 to 42 mm in men or 36 to 39 mm in women) and no features of associated connective tissue disorder or familial thoracic aortic aneurysm syndrome may participate in low and moderate static and dynamic competitive sports (classes IA, IB, IC, IIA, IIB, and IIC) with a low likelihood of significant bodily collision (figure 3 and table 1).

●Adult competitive athletes with bicuspid aortic valve and a severely dilated aorta (z-score >3.5 to 4, or >43 mm in men or >40 mm in women) should not participate in any competitive sports that involve the potential for bodily collision (table 1). Athletes with a bicuspid aortic valve and a dilated aorta measuring 43 to 45 mm may participate in low-intensity competitive sports (class IA) with a low likelihood of bodily collision (figure 3).

●Athletes with bicuspid aortic valve and a markedly dilated aorta (>45 mm) should not participate in any competitive sports.

In practical terms, many adolescents and young adults with bicuspid aortic valves have mildly dilated aortas (ie, z-score >2 to 3), yet the absolute aortic diameter remains in a range (ie, 4.0 to 4.5 cm) that is associated with a low risk of acute aortic dissection. In these cases, after an informed and shared decision-making discussion, many experts agree to allow continued participation in competitive sports with serial imaging follow-up of aortic dimensions. In these instances, it is important to exclude cases of underlying genetic aortopathy (ie, those associated with familial or heritable aneurysm disease) and Turner syndrome, since these conditions have higher risks of aortic complications. Avoidance of intense weight training is recommended for athletes with significant aortic dilation who choose to continue to participate in competitive sports.

NONCARDIAC SURGERY — Patients with bicuspid aortic valve may require noncardiac surgery. The risks of surgery depend largely upon the severity of associated aortic stenosis or aortic regurgitation, as well as any accompanying ascending aortic disease. The management of the patient with aortic stenosis or aortic regurgitation undergoing noncardiac surgery is discussed separately. (See "Noncardiac surgery in adults with aortic stenosis" and "Noncardiac surgery in patients with mitral or aortic regurgitation", section on 'Chronic aortic regurgitation'.)

PREGNANCY — Preconception evaluation and counseling, and management of bicuspid aortic valve disease and aortopathy during pregnancy are discussed separately. (See "Bicuspid aortic valve: Management during pregnancy".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Bicuspid aortic valve" and "Society guideline links: Cardiac valve disease" and "Society guideline links: Aortic dissection and other acute aortic syndromes" and "Society guideline links: Congenital heart disease in adults".)

SUMMARY AND RECOMMENDATIONS

●General management – The management of bicuspid aortic valve disease in adults includes surveillance, intervention for aortic valve disease and aortopathy, treatment of hypertension, measures to address the risk of infective endocarditis, counseling patients on physical activity, management of risk if noncardiac surgery is required, and counseling and management prior to and during pregnancy. (See 'Introduction' above.)

●Monitoring – To enable timely intervention, all patients with bicuspid aortic valves should be monitored for progressive aortic valve dysfunction (stenosis and/or regurgitation) as well as for thoracic aortic dilation given the risk of aneurysm formation and aortic dissection. Serial evaluation of the size and morphology of the aortic sinuses and ascending aorta is recommended, with the examination interval determined by the aortic size, the rate of progression of aortic dilation, and other risk factors, including family history. When the aortic diameter approaches a surgical threshold, more frequent imaging is reasonable. (See 'How frequently to monitor' above.)

Transthoracic echocardiography (TTE) is used for monitoring the thoracic aorta if image quality is adequate. If any segment of the thoracic aorta is not adequately visualized by TTE, any segment measures ≥45 mm, or aortic coarctation cannot be ruled out, then the entire thoracic aorta should be imaged by ECG-gated magnetic resonance imaging or ECG-gated computed tomography. (See 'How to monitor' above.)

●Limited role of drug therapy – The role of pharmacologic therapy for patients with bicuspid aortic valve disease is limited, as no drug has been shown to improve outcomes in patients with bicuspid aortic valve. (See 'Pharmacologic therapy' above.)

•For hypertension – If hypertension is present, it should be treated according to standard guidelines. (See "Overview of hypertension in adults".)

For patients with bicuspid aortic valve, chronic aortic regurgitation, and systemic hypertension (systolic blood pressure >140 mmHg), vasodilators (such as angiotensin converting enzyme inhibitors, angiotensin II receptor blockers, or dihydropyridine calcium channel blockers) are favored since they may reduce systolic blood pressure in this setting. Beta blocker therapy may be less effective in this setting. (See "Natural history and management of chronic aortic regurgitation in adults", section on 'Pharmacologic therapy'.)

•Without hypertension – For patients with bicuspid aortic valve and dilated aortic root or ascending aorta without hypertension, there are no pharmacologic therapies proven to lessen aortic dilation or lessen the risk of aortic dissection or rupture. Some clinicians use beta blockers in this setting based upon theoretical benefit and likely minimal risk. (See "Management of thoracic aortic aneurysm in adults", section on 'Antihypertensive therapies'.)

●Endocarditis – Individuals with bicuspid aortic valve should receive education about the risk of endocarditis and means of reducing the risk, including good dental care and oral health practices, awareness of symptoms of infection (including symptoms suggesting endocarditis, such as unexplained fevers, chills, and night sweats), and the importance of prompt reporting of symptoms of concern to health care providers. (See "Clinical manifestations and diagnosis of bicuspid aortic valve in adults", section on 'Infective endocarditis'.)

●Exercise – Recommendations about exercise and physical activity for individuals with a bicuspid aortic valve are tailored to the type and severity of valve disease present (aortic stenosis or aortic regurgitation) and the presence of a dilated aortic root or ascending aorta. (See 'Physical activity and exercise' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Martin G Keane, MD, FACC, FAHA, FASE, Thomas P Graham, MD, and Catherine M Otto, MD, who contributed to earlier versions of this topic review.

The UpToDate editorial staff also acknowledges Martin St. John Sutton, MD (deceased), who contributed to earlier versions of this topic.