Unicuspid Aortic Valve in Adults: A Systematic Review Farouk Mookadam, Venkata R. Thota, Ana Maria Garcia-Lopez, Usha R. Emani, Mohsen S. Alharthi, Jose Zamorano, Bijoy K. Khandheria Cardiovascular Disease & Internal Medicine, Mayo Clinic Arizona, Scottsdale, Arizona, USA The natural history of the unicuspid aortic valve (UAV) is poorly described in the literature, the first report having been made in 1958 by Edwards (1). It is unclear whether this anomaly shares any of the char- acteristics and associations of the more common and more easily recognized bicuspid aortic valve (BAV), or if there is an association with other cardiac or extracar- diac abnormalities. Thus, in an attempt to answer these questions, a systematic overview was performed of the medical literature. The normal aortic valve consists of valve cusps, sinuses and commissures (2). The most frequent con- genital malformation of the aortic valve is the presence of a BAV, with an incidence in the general population estimated at 0.9-1.4%, and a male:female ratio of 2:1 (3). This anomaly likely has a genetic basis, with epi- demiological data suggesting a familial pattern in some cases of left heart obstructive lesions (coarctation of the aorta, aortic valve stenosis and hypoplastic left heart syndrome) (4). A BAV is present in more than 50% of the cases with aortic coarctation (5), and in 10- 12% of females with Turner’s syndrome (6). Tissue abnormalities in patients with BAV are not limited to the valve, but may involve the ascending aortic media, with an increased risk of aortic aneurysm and a five- to nine-fold greater risk of aortic dissection (7). Developmental abnormalities regarding the number of valvular cusps other than BAV include unicuspid, quadricuspid, and pentacuspid aortic valves (8). Materials and methods A systematic search, through the Ovid Technologies (OVID) platform, of the English, Spanish, Portuguese Address for correspondence: Farouk Mookadam MD, FRCPC, FACC, MSc (HRM), Cardiovascular Disease & Internal Medicine, Mayo Clinic Arizona, 13400 E Shea Blvd., Scottsdale, AZ 85259-5499, USA e-mail: mookadam.farouk@mayo.edu © Copyright by ICR Publishers 2010 Background and aim of the study: The natural history of the unicuspid aortic valve (UAV) is poorly described in the literature. In order to study the asso- ciation between UAV with any other cardiac or extra cardiac abnormalities, an evidence-based systematic review was carried out. Methods: A computerized search was carried out of the medical literature published between 1st January 1966 and 1st September 2008 of the following data- bases: MEDLINE; EMBASE; Web of Science; and the Cochrane Database. Results: A total of 231 cases of adult UAV was identi- fied in 38 articles. The mean patient age was 42 years, and the most common presenting symptoms report- ed (in 52 cases) included dyspnea (44%; n = 23), angi- na (21%; n = 11), and dizziness or syncope (8%; n = 4). The most common lesion in UAV was isolated aortic stenosis (AS) (41%; n = 95) and AS with or without aortic regurgitation (28%; n = 64). The preoperative diagnosis of UAV is rare, and 139 cases (60%) of UAV were reported at autopsy or by examination of surgi- cally excised valves. Aortic valve replacement was performed in 166 cases (82%). Concomitant aortic surgery was performed in 47 of the UAV cases (23%), either for a dilated or aneurysmal aorta. Conclusion: UAV shares many of the features of bicuspid aortic valve, including valvular dysfunc- tion, aortic dilatation, aortic dissection, and dys- trophic calcification, although these conditions develop at an earlier age and progress at a faster pace in UAV. Further investigations are warranted regard- ing the possibility of a familial incidence, associated histopathological changes in the aorta, preoperative diagnostic tools, ideal follow up and surgical inter- vention. The Journal of Heart Valve Disease 2010;19:79-85