DIAGNOSING AND MANAGING BICUSPID AORTIC VALVE Azam Ansari, MD and Ryan Devine, BS Echocardiography is the key to early diagnosis and effective management of this often silent cardiac abnormality. ound in approximately 1% This contributed to the difficulty of A transthoracic echocardiogram to 2% of the general U.S. detecting the condition (particularly showed eccentric closure and two population, bicuspid aortic in young, asymptomatic patients) cusps of the aortic valve when F valve (BAV) is the most and, thus, increased the vulnerabil- opening (Figure 1 A and B). Appli- common congenital heart abnor- ity of many patients to infective en- cation of color-flow Doppler re- mality.1 Because the condition is docarditis. Today, however, both vealed the presence of a mosaic often asymptomatic, its presence transthoracic and transesophageal color aortic regurgitation (AR) jet may go undetected for many years.2 echocardiographic procedures can below the aortic orifice extending And though some people with BAV help providers diagnose the disease into the left ventricular outflow never experience complications, the early in its course. tract (Figure 1 C). The patient’s left condition frequently predisposes In this article, we describe two ventricular size was at the upper the aortic valve to degenerative cal- cases of congenital BAV: one in an limit of normal, with normal left cification that can culminate in adolescent and one in a middle- ventricular function. stenosis, incompetence, or both. In aged man. These cases illustrate the In the absence of surgical indica- addition, the valve becomes increas- role of echocardiography in the tions, the patient was instructed in ingly susceptible to infective endo- timely diagnosis and appropriate infective endocarditis prophylaxis carditis. For these reasons, early management of BAV in patients of before dental, genitourinary, or gas- recognition of BAV and periodic fol- all ages. We also discuss the basic trointestinal surgery and counseled low-up are of utmost importance. presentation, diagnosis, and man- about periodic follow-up. Before the introduction of echo- agement of the condition. cardiography into clinical practice, CASE 2: BAV IN MIDDLE AGE definitive BAV diagnosis was de- CASE 1: BAV IN ADOLESCENCE A 50-year-old man was evaluated layed until the patient underwent A young man, aged 17 years, pre- for a harsh basal systolic murmur, cardiac catheterization, angiogra- sented to a multispecialty practice fatigue, and dyspnea on minimal phy, or surgery—or until the excised for evaluation of a heart murmur exertion. He reported no chest valve was examined pathologically.3 that had been detected by his pri- pain, syncope, or history of rheu- mary care provider. He was asymp- matic disease or scarlet fever. tomatic and had no history of After a transthoracic echocar- Dr. Ansari is a cardiologist in the department of car- rheumatic or scarlet fever. Physical diogram yielded suboptimal re- diovascular medicine at Fairview Southdale Hospi- tal, Edina, MN and Abbott Northwestern Hospital examination revealed a grade I/VI sults, another echocardiogram was in Minneapolis, MN. He is also a fellow of the early diastolic murmur following performed using the transesoph- American College of Cardiology and the American the aortic component of the second ageal route. A foreshortened four- Heart Association. Mr. Devine is a student of osteo- pathic medicine at Philadelphia College of Osteo- sound. The murmur radiated down chamber view in transverse axis pathic Medicine, Philadelphia, PA. the left parasternal area. revealed two aortic valve cusps of Continued on page 86 JULY 2004 • FEDERAL PRACTITIONER • 81 BICUSPID AORTIC VALVE Continued from page 81 unequal length with doming of the stenotic orifice (Figure 2 B). Cardiac valve replacement. During this pro- left coronary cusp, an eccentric nar- catheterization confirmed a peak cedure, the surgeon found the aor- row orifice, and poststenotic dila- mean gradient of 86 mm Hg across tic valve to be thickened, partially tion (50 mm) of the aortic root the aortic valve. Coronary an- calcified, severely distorted, and (Figure 2 A)—all of which indicated giogram was normal. stenotic. Pathologic examination of a BAV with aortic stenosis (AS). Because of a reduction in left the excised valve confirmed severe Color-flow Doppler imaging showed ventricular systolic function (re- AS in a degenerated BAV. disturbed blood flow beginning flected by an ejection fraction of After the prosthetic valve was below the aortic valve and extend- less than 50%), the evaluating placed, the patient’s symptoms im- ing into the aortic root through the physician recommended aortic proved markedly, his left ventricu- lar hypertrophy (LVH) regressed, and he was able to return to full- time employment. The patient also began oral anticoagulation therapy, with monitoring for an interna- tional normalized ratio of 2.5 to 3. RECOGNIZING AND EVALUATING BAV Clinicians should consider the pos- Figure 1. Transthoracic echocardiogram of a 17-year-old male patient with a congenital bicuspid sibility of BAV when AS occurs in aortic valve presenting as isolated aortic regurgitation. The parasternal long-axis view (A) shows isolation, in the presence of an eccentric closure (open, short arrow) of the aortic valve due to unequal length of the leaflets ejection systolic click in the second (thin arrows); the parasternal short-axis view (B) shows the aortic root, which contains an open or third right or left intercostal bicuspid aortic valve; and the modified apical four-chamber view (C) focuses on the aortic regur- gitation jet (short, closed arrow). Abbreviations: BAV = bicuspid aortic valve; LA = left atrium. space, or in the presence of other congenital heart diseases (such as coarctation of the aorta, high mem- branous ventricular septal defect, patent ducts, or aneurysm of the sinus of Valsalva). The incidence of BAV is higher in patients with these defects than in the general popula- tion. As the first case illustrates, it’s also important to suspect congeni- tal BAV in any patient whose physi- cal examination suggests isolated AR and whose history includes nei- ther rheumatic nor scarlet fever. Transthoracic echocardiography is the gold standard for confirming a BAV diagnosis. Echocardiographic features of BAV and its sequelae Figure 2. Transesophageal echocardiogram of a 50-year-old male patient with severe isolated have been described in detail else- aortic stenosis originating in a bicuspid aortic valve. The left ventricular outflow tract view (A) where.4,5 It’s important to note that shows two unequal aortic valve leaflets with an eccentric, slit-like, narrow opening (small arrow- head). The same view with color flow Doppler application (B) shows a mosaic color jet originat- echocardiography plays a key role ing below the valve and traversing through the narrow orifice. Abbreviations: AML = anterior not only in diagnosing patients with mitral leaflet; AR = aortic root; ASJ = aortic stenosis jet; IVS = interventricular septum; LA = left BAV but also in obtaining important atrium; LV = left ventricle; MV = mitral valve; PML = posterior mitral leaflet; RV = right ventricle. data about the natural history of the Compass: A = anterior; L = left; P = posterior; R = right. disease. Changes in the structure and function of the valve can be Continued on page 89 86 • FEDERAL PRACTITIONER • JULY 2004 BICUSPID AORTIC VALVE Continued from page 86 noted as early as one year or as late surgical valve replacement. Even the use of echocardiography, the as 10 to 20 years after initial diagno- in the presence of such clear sur- cornerstone for BAV diagnosis and sis. About 30% of patients may re- gical indications, however, the evaluation, clinicians can help re- main asymptomatic until they are risk of valve replacement (1% duce the morbidity and mortality about 70 years old.4 mortality and 1% morbidity) must associated with the condition by be weighed against the risks of optimizing management. ● NONSURGICAL MANAGEMENT delaying the procedure, partic- All patients with confirmed BAV, ularly in patients with early symp- The authors wish to express their asymptomatic or symptomatic, toms. Asymptomatic patients sincere appreciation to Mrs. Na- should receive lifelong infective generally have a good prognosis dine Sinness for her help in endocarditis prophylaxis before without valve replacement, and preparing this manuscript. dental, genitourinary, or gastroin- should be offered nonsurgical testinal surgery as recommended management as described in the The opinions expressed herein are by the American Heart Asso- previous section.8 those of the authors and do not ciation.6 They also need periodic In evaluating the surgical candi- necessarily reflect those of Federal surveillance to detect any transi- dacy of a patient with BAV and AR, Practitioner, Quadrant HealthCom tion from normal to abnormal clinicians should consider the pa- Inc., the U.S. government, or any hemodynamic status for timely tient’s symptoms, exercise capac- of its agencies. This article may and appropriate intervention. ity, left ventricular dimensions, and discuss unlabeled or investiga- Echocardiography and exercise ejection fraction. Decreasing exer- tional use of certain drugs. Please testing often helps in such routine cise capacity, failure of ejection review complete prescribing infor- evaluations. In general, if the mean fraction to rise during exercise, and mation for specific drugs or drug aortic valve gradient exceeds 40 to