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Echocardiographic Prevalence of Bicuspid Aortic Valve in the Population
ORIGINAL ARTICLE
Original Article
Echocardiographic Prevalence of Bicuspid Aortic Valve in the Population Mohammad-Reza Movahed, PhD, FCCP ∗ , Absalom D. Hepner, MD and Mastaneh Ahmadi-Kashani, BS University of California, Irvine Medical Center, Department of Medicine, Division of Cardiology, United States
Introduction: The exact prevalence of bicuspid aortic valve (BAV) is controversial. We studied the prevalence of BAV using two large independent echocardiographic databases. Methods: We analyzed 24,265 echocardiograms performed at our academic institution between 1984 and 1998 for various clinical reasons and 1742 echocardiograms that were obtained by screening teenage athletes in Southern California. The total prevalence of BAV was calculated. Results: The first database revealed a gender distribution of 11,339 (47%) male and 12,926 (53%) female patients. The second database consisted of 1172 (67%) male and 570 (33%) female athletes. The echocardiographic prevalence of BAV was 0.6% in the larger database and 0.5% in the smaller athletic database. Conclusion: We found the prevalence of bicuspid aortic valve in two large databases to be between 0.5% and 0.6%. This figure was consistent across different ages, in both databases. (Heart, Lung and Circulation 2006;15:297–299) © 2006 Australasian Society of Cardiac and Thoracic Surgeons and the Cardiac Society of Australia and New Zealand. Published by Elsevier Inc. All rights reserved. Keywords. Bicuspid aortic valve; BAV; Prevalence; Echocardiography; Athletes; Congenital valve disease
Introduction
T
he bicuspid aortic valve (BAV) is one of the most common congenital heart defects. It can progress to aortic stenosis or regurgitation and is associated with higher rates of infectious endocarditis. The exact prevalence of the condition is not known. The prevalence of BAV was originally estimated from reviews of autopsy series. In the 1920s Lewis and Grant found the prevalence of bicuspid aortic valve to be 1.4% and 0.9%, respectively.1,2 Roberts later published data supporting the figure of 0.9%.10 Very large studies were closer to the higher figure of 1.2–1.4%.4,5 In the 1990s studies were first done using echocardiographic screening of asymptomatic populations. One large study in Africa found a considerably lower prevalence of 0.1%.11 However, two smaller but more recent studies found rates between 0.5% and 0.6%.12,13 The largest study to date combined both methods by analyzing the autopsy reports, medical records and an echocardioReceived 25 December 2005; received in revised form 30 March 2006; accepted 3 June 2006 ∗ Corresponding author at: University of Arizona Sarver Heart Center, Department of Medicine, Division of Cardiology, 1501 North Campbell Ave., Tucson, AZ 85724, United States. Tel.: +1 520 626 2000; fax: +1 949 400 0091. E-mail addresses: [email protected], [email protected] (M.-R. Movahed)
graphic database involving 44,013 children born in Iceland. This showed an overall prevalence of 0.1%. The goal of our study was to clarify the actual prevalence of BAV. We have at the University of California, Irvine, a large database of 23,957 echocardiographic studies done for a wide spectrum of diagnoses. We also have a database of 1742 screening echocardiograms done on teenage athletes. Each of these databases is larger than any previously published studies reporting on the echocardiographic prevalence of BAV. The UC Irvine database, by itself, is larger than the largest autopsy series published on this matter (Table 1).
Methods We retrospectively analyzed two large databases. One included 24,265 echocardiograms performed at our institution ordered by clinicians between 1984 and 1998 for various indications. The echocardiograms were interpreted by different cardiologists at our institution during study period. The diagnosis of BAV was based on visual estimation by the interpreting cardiologists. The second database was from a study of 1742 echocardiograms performed during the screening of a large number of healthy teenage athletes in Southern California. The screenings were organized by A Heart for Sports (a non-profit organization for the screening of young athletes). The athletes were recruited through advertisements and by contacting local
© 2006 Australasian Society of Cardiac and Thoracic Surgeons and the Cardiac Society of Australia and New Zealand. Published by Elsevier Inc. All rights reserved.
1443-9506/04/$30.00 doi:10.1016/j.hlc.2006.06.001
ORIGINAL ARTICLE
298
Movahed et al. Prevalence of bicuspid aortic valve
Heart, Lung and Circulation 2006;15:297–299
Table 1. Summary of Studies on Prevalence of BAV Study al.3
Stephensen et Larson and Edwards4 Rose5 Gupta et al.6 Datta et al.7 Waller et al.8 Pauperio et al.9 Roberts10 Anabwani and Bonhoeffer11 Basso et al.12 Steinberger et al.13
Method
Year
Subjects
Medical, autopsy records and echocardiography Autopsy Autopsy Signs, symptoms, echocardiography Autopsy Autopsy Autopsy Autopsy Echocardiography Echocardiography Echocardiography
2004 1984 1986 1992 1988 1992 1999 1970 1996 2004 2000
44013 21417 18132 10263 8800 2007 2000 1440 1115 817 357
Prevalence (%) 0.1 1.4 1.2 0.01 0.6 0.8 0.6 0.9 0.1 0.5 0.6
Table 2. The Prevalence of BAV in Two Large Databases Mean Age (years) Database
Patients (n)
University of California, Irvine Athletic screening database
23957 1742
With BAV
Without BAV
40 16
schools. The echocardiograms were performed by experienced echocardiographers and interpreted by cardiologists onsite. The screenings were free of charge and were sponsored by community. The total prevalence of BAV was calculated and stratified based on gender and age.
Results The first database revealed a gender distribution of 11,339 male (47%) and 12,926 (53%) female patients. The second database consisted of 1172 (67%) male and 570 (33%) female athletes. The echocardiographic prevalence of BAV was 0.6% in the larger database and 0.5% in the smaller athletic database (Table 2). The mean age of patients with BAV in the larger of the two echocardiographic databases was 31.8 ± 14.3 vs. 51.4 ± 18.5 years in those without BAV. The mean age of athletes with BAV was 15.6 ± 3.8 vs. 17.6 ± 8.2 years in those without BAV. The prevalence of BAV in males was 0.9% vs. 0.3% in females in the larger database. In the atheletes’ database the prevalence of BAV was 0.6% in males and 0.2% in females.
Discussion Using two large databases we found that the prevalence of bicuspid aortic valve was between 0.5% and 0.6%. This figure matches the results found by two other smaller echocardiographic studies which used prospective screening of children and adolescents.12,13 It also approximates the results of the two latest autopsy series to be published.7,8 It is far greater than the 0.1% reported from largest study to date, using medical records, autopsy studies and an echocardiographic database of 44,000 children born in Iceland. However, it should be noted that this study did not involve screening and therefore subjects who remain asymptomatic may be undiagnosed. The sec-
51 18
Prevalence in Females (%) 0.3 0.2
Prevalence in Males (%) 0.9 0.6
Overall Prevalence (%) 0.6 0.5
ond largest study applying echocardiography, a study of 10,000 children in India, which found only one case of BAV, was similarly limited by the fact that children did not undergo echocardiography unless they had signs or symptoms of congenital heart disease. In contrast, several large autopsy series have found a much higher prevalence, ranging from 0.9% to 1.4%.1,2,4,5 Why our figure is significantly different from those published in those autopsy series is unclear. It is possible that echocardiography underestimates the true prevalence of BAV. However, it should be noted that the most recent autopsy series published, both with large numbers (Table 1),7–9 found a notably lower prevalence of 0.6–0.8%, raising the possibility that other unaccounted factors may be affecting the difference. For example, the rates of autopsy in men may be greater than those in women. Rose, for example did not report the demographic breakdown,5 but Waller et al.8 and Pauperio et al.,9 reported that 67% and 75% of cases, respectively, were male.8 Our finding that three or four males are affected for every female is consistent with the statistic reported by Roberts,10 but far less than the ratio of 11 to one reported by Datta, et al.7 Since neither study published the demographic breakdown of all patients undergoing autopsy, these figures are difficult to compare. In comparison, the sex distribution in the large study of 44,000 children in Iceland showed 2.5 males being affected for every female. As described above, there was no screening in this study and so there may have been many unrecognized cases.3
Limitations Our data were extracted from databases and therefore the study was not prospective. The diagnosis of BAV was not independently verified. The echocardiograms were interpreted by different cardiologists and we cannot determine the inter-observer variability or adherence to established
guidelines. The diagnosis of BAV is a subjective diagnosis and dependent on the quality of images. Therefore, the prevalence of BAV could have been underestimated.
Conclusion We found the prevalence of bicuspid aortic valve in two large databases to be between 0.5% and 0.6%. This figure was consistent across different ages, in both databases. The ratio of males to females affected was three or four to one.
References 1. Lewis T, Grant RT. Observation relating to subacute infective endocarditis. Heart 1923;10:21–99. 2. Grant R, Wood Jr JE, Jones TD. Heart valve irregularities in relation to subacute bacterial endocarditis. Heart 1928;14:247–55. 3. Stephensen SS, Sigfusson G, Eiriksson H, Sverrisson JT, Torfason B, Haraldsson A, et al. Congenital cardiac malformations in Iceland from 1990 through 1999. Cardiol Young 2004;14(4):396–401. 4. Larson EW, Edwards WD. Risk factors for aortic dissection: a necropsy study of 161 cases. Am J Cardiol 1984;53:849–55.
Movahed et al. Prevalence of bicuspid aortic valve
299
5. Rose AG. Etiology of acquired valvular heart disease in adults. A survey of 18,132 autopsies and 100 consecutive valvereplacement operations. Arch Pathol Lab Med 1986;110:385–8. 6. Gupta I, Gupta ML, Parihar A, Gupta CD. Epidemiology of rheumatic and congenital heart diseases in school children. J Indian Med Assoc 1992;90(3):57–9. 7. Datta BN, Bhusnurmath B, Khattri HN, Sapru RP, Bidwai PS, Wahi PL. Anatomically isolated aortic valve disease. Morphologic study of 100 cases at autopsy. Jpn Heart J 1988;29:661–70. 8. Waller BF, Catellier MJ, Clark MA, Hawley DA, Pless JE. Cardiac pathology in 2007 consecutive forensic autopsies. Clin Cardiol 1992;15(10):760–5. 9. Pauperio HM, Azevedo AC, Ferreira CS. The aortic valve with two leaflets—a study in 2000 autopsies. Cardiol Young 1999;9(5):488–98. 10. Roberts WC. The congenitally bicuspid aortic valve. A study of 85 autopsy cases. Am J Cardiol 1970;26:72–83. 11. Anabwani GM, Bonhoeffer P. Prevalence of heart disease in school children in rural Kenya using colour-flow echocardiography. East Afr Med J 1996;73(4):215–7. 12. Basso C, Boschello M, Perrone C, Mecenero A, Cera A, Bicego D, et al. An echocardiographic survey of primary school children for bicuspid aortic valve. Am J Cardiol 2004;93(5):661–3. 13. Steinberger J, Moller JH, Berry JM, Sinaiko AR. Echocardiographic diagnosis of heart disease in apparently healthy adolescents. Pediatrics 2000;105(4):815–8.
ORIGINAL ARTICLE
Heart, Lung and Circulation 2006;15:297–299
Original Article
Echocardiographic Prevalence of Bicuspid Aortic Valve in the Population Mohammad-Reza Movahed, PhD, FCCP ∗ , Absalom D. Hepner, MD and Mastaneh Ahmadi-Kashani, BS University of California, Irvine Medical Center, Department of Medicine, Division of Cardiology, United States
Introduction: The exact prevalence of bicuspid aortic valve (BAV) is controversial. We studied the prevalence of BAV using two large independent echocardiographic databases. Methods: We analyzed 24,265 echocardiograms performed at our academic institution between 1984 and 1998 for various clinical reasons and 1742 echocardiograms that were obtained by screening teenage athletes in Southern California. The total prevalence of BAV was calculated. Results: The first database revealed a gender distribution of 11,339 (47%) male and 12,926 (53%) female patients. The second database consisted of 1172 (67%) male and 570 (33%) female athletes. The echocardiographic prevalence of BAV was 0.6% in the larger database and 0.5% in the smaller athletic database. Conclusion: We found the prevalence of bicuspid aortic valve in two large databases to be between 0.5% and 0.6%. This figure was consistent across different ages, in both databases. (Heart, Lung and Circulation 2006;15:297–299) © 2006 Australasian Society of Cardiac and Thoracic Surgeons and the Cardiac Society of Australia and New Zealand. Published by Elsevier Inc. All rights reserved. Keywords. Bicuspid aortic valve; BAV; Prevalence; Echocardiography; Athletes; Congenital valve disease
Introduction
T
he bicuspid aortic valve (BAV) is one of the most common congenital heart defects. It can progress to aortic stenosis or regurgitation and is associated with higher rates of infectious endocarditis. The exact prevalence of the condition is not known. The prevalence of BAV was originally estimated from reviews of autopsy series. In the 1920s Lewis and Grant found the prevalence of bicuspid aortic valve to be 1.4% and 0.9%, respectively.1,2 Roberts later published data supporting the figure of 0.9%.10 Very large studies were closer to the higher figure of 1.2–1.4%.4,5 In the 1990s studies were first done using echocardiographic screening of asymptomatic populations. One large study in Africa found a considerably lower prevalence of 0.1%.11 However, two smaller but more recent studies found rates between 0.5% and 0.6%.12,13 The largest study to date combined both methods by analyzing the autopsy reports, medical records and an echocardioReceived 25 December 2005; received in revised form 30 March 2006; accepted 3 June 2006 ∗ Corresponding author at: University of Arizona Sarver Heart Center, Department of Medicine, Division of Cardiology, 1501 North Campbell Ave., Tucson, AZ 85724, United States. Tel.: +1 520 626 2000; fax: +1 949 400 0091. E-mail addresses: [email protected], [email protected] (M.-R. Movahed)
graphic database involving 44,013 children born in Iceland. This showed an overall prevalence of 0.1%. The goal of our study was to clarify the actual prevalence of BAV. We have at the University of California, Irvine, a large database of 23,957 echocardiographic studies done for a wide spectrum of diagnoses. We also have a database of 1742 screening echocardiograms done on teenage athletes. Each of these databases is larger than any previously published studies reporting on the echocardiographic prevalence of BAV. The UC Irvine database, by itself, is larger than the largest autopsy series published on this matter (Table 1).
Methods We retrospectively analyzed two large databases. One included 24,265 echocardiograms performed at our institution ordered by clinicians between 1984 and 1998 for various indications. The echocardiograms were interpreted by different cardiologists at our institution during study period. The diagnosis of BAV was based on visual estimation by the interpreting cardiologists. The second database was from a study of 1742 echocardiograms performed during the screening of a large number of healthy teenage athletes in Southern California. The screenings were organized by A Heart for Sports (a non-profit organization for the screening of young athletes). The athletes were recruited through advertisements and by contacting local
© 2006 Australasian Society of Cardiac and Thoracic Surgeons and the Cardiac Society of Australia and New Zealand. Published by Elsevier Inc. All rights reserved.
1443-9506/04/$30.00 doi:10.1016/j.hlc.2006.06.001
ORIGINAL ARTICLE
298
Movahed et al. Prevalence of bicuspid aortic valve
Heart, Lung and Circulation 2006;15:297–299
Table 1. Summary of Studies on Prevalence of BAV Study al.3
Stephensen et Larson and Edwards4 Rose5 Gupta et al.6 Datta et al.7 Waller et al.8 Pauperio et al.9 Roberts10 Anabwani and Bonhoeffer11 Basso et al.12 Steinberger et al.13
Method
Year
Subjects
Medical, autopsy records and echocardiography Autopsy Autopsy Signs, symptoms, echocardiography Autopsy Autopsy Autopsy Autopsy Echocardiography Echocardiography Echocardiography
2004 1984 1986 1992 1988 1992 1999 1970 1996 2004 2000
44013 21417 18132 10263 8800 2007 2000 1440 1115 817 357
Prevalence (%) 0.1 1.4 1.2 0.01 0.6 0.8 0.6 0.9 0.1 0.5 0.6
Table 2. The Prevalence of BAV in Two Large Databases Mean Age (years) Database
Patients (n)
University of California, Irvine Athletic screening database
23957 1742
With BAV
Without BAV
40 16
schools. The echocardiograms were performed by experienced echocardiographers and interpreted by cardiologists onsite. The screenings were free of charge and were sponsored by community. The total prevalence of BAV was calculated and stratified based on gender and age.
Results The first database revealed a gender distribution of 11,339 male (47%) and 12,926 (53%) female patients. The second database consisted of 1172 (67%) male and 570 (33%) female athletes. The echocardiographic prevalence of BAV was 0.6% in the larger database and 0.5% in the smaller athletic database (Table 2). The mean age of patients with BAV in the larger of the two echocardiographic databases was 31.8 ± 14.3 vs. 51.4 ± 18.5 years in those without BAV. The mean age of athletes with BAV was 15.6 ± 3.8 vs. 17.6 ± 8.2 years in those without BAV. The prevalence of BAV in males was 0.9% vs. 0.3% in females in the larger database. In the atheletes’ database the prevalence of BAV was 0.6% in males and 0.2% in females.
Discussion Using two large databases we found that the prevalence of bicuspid aortic valve was between 0.5% and 0.6%. This figure matches the results found by two other smaller echocardiographic studies which used prospective screening of children and adolescents.12,13 It also approximates the results of the two latest autopsy series to be published.7,8 It is far greater than the 0.1% reported from largest study to date, using medical records, autopsy studies and an echocardiographic database of 44,000 children born in Iceland. However, it should be noted that this study did not involve screening and therefore subjects who remain asymptomatic may be undiagnosed. The sec-
51 18
Prevalence in Females (%) 0.3 0.2
Prevalence in Males (%) 0.9 0.6
Overall Prevalence (%) 0.6 0.5
ond largest study applying echocardiography, a study of 10,000 children in India, which found only one case of BAV, was similarly limited by the fact that children did not undergo echocardiography unless they had signs or symptoms of congenital heart disease. In contrast, several large autopsy series have found a much higher prevalence, ranging from 0.9% to 1.4%.1,2,4,5 Why our figure is significantly different from those published in those autopsy series is unclear. It is possible that echocardiography underestimates the true prevalence of BAV. However, it should be noted that the most recent autopsy series published, both with large numbers (Table 1),7–9 found a notably lower prevalence of 0.6–0.8%, raising the possibility that other unaccounted factors may be affecting the difference. For example, the rates of autopsy in men may be greater than those in women. Rose, for example did not report the demographic breakdown,5 but Waller et al.8 and Pauperio et al.,9 reported that 67% and 75% of cases, respectively, were male.8 Our finding that three or four males are affected for every female is consistent with the statistic reported by Roberts,10 but far less than the ratio of 11 to one reported by Datta, et al.7 Since neither study published the demographic breakdown of all patients undergoing autopsy, these figures are difficult to compare. In comparison, the sex distribution in the large study of 44,000 children in Iceland showed 2.5 males being affected for every female. As described above, there was no screening in this study and so there may have been many unrecognized cases.3
Limitations Our data were extracted from databases and therefore the study was not prospective. The diagnosis of BAV was not independently verified. The echocardiograms were interpreted by different cardiologists and we cannot determine the inter-observer variability or adherence to established
guidelines. The diagnosis of BAV is a subjective diagnosis and dependent on the quality of images. Therefore, the prevalence of BAV could have been underestimated.
Conclusion We found the prevalence of bicuspid aortic valve in two large databases to be between 0.5% and 0.6%. This figure was consistent across different ages, in both databases. The ratio of males to females affected was three or four to one.
References 1. Lewis T, Grant RT. Observation relating to subacute infective endocarditis. Heart 1923;10:21–99. 2. Grant R, Wood Jr JE, Jones TD. Heart valve irregularities in relation to subacute bacterial endocarditis. Heart 1928;14:247–55. 3. Stephensen SS, Sigfusson G, Eiriksson H, Sverrisson JT, Torfason B, Haraldsson A, et al. Congenital cardiac malformations in Iceland from 1990 through 1999. Cardiol Young 2004;14(4):396–401. 4. Larson EW, Edwards WD. Risk factors for aortic dissection: a necropsy study of 161 cases. Am J Cardiol 1984;53:849–55.
Movahed et al. Prevalence of bicuspid aortic valve
299
5. Rose AG. Etiology of acquired valvular heart disease in adults. A survey of 18,132 autopsies and 100 consecutive valvereplacement operations. Arch Pathol Lab Med 1986;110:385–8. 6. Gupta I, Gupta ML, Parihar A, Gupta CD. Epidemiology of rheumatic and congenital heart diseases in school children. J Indian Med Assoc 1992;90(3):57–9. 7. Datta BN, Bhusnurmath B, Khattri HN, Sapru RP, Bidwai PS, Wahi PL. Anatomically isolated aortic valve disease. Morphologic study of 100 cases at autopsy. Jpn Heart J 1988;29:661–70. 8. Waller BF, Catellier MJ, Clark MA, Hawley DA, Pless JE. Cardiac pathology in 2007 consecutive forensic autopsies. Clin Cardiol 1992;15(10):760–5. 9. Pauperio HM, Azevedo AC, Ferreira CS. The aortic valve with two leaflets—a study in 2000 autopsies. Cardiol Young 1999;9(5):488–98. 10. Roberts WC. The congenitally bicuspid aortic valve. A study of 85 autopsy cases. Am J Cardiol 1970;26:72–83. 11. Anabwani GM, Bonhoeffer P. Prevalence of heart disease in school children in rural Kenya using colour-flow echocardiography. East Afr Med J 1996;73(4):215–7. 12. Basso C, Boschello M, Perrone C, Mecenero A, Cera A, Bicego D, et al. An echocardiographic survey of primary school children for bicuspid aortic valve. Am J Cardiol 2004;93(5):661–3. 13. Steinberger J, Moller JH, Berry JM, Sinaiko AR. Echocardiographic diagnosis of heart disease in apparently healthy adolescents. Pediatrics 2000;105(4):815–8.
ORIGINAL ARTICLE
Heart, Lung and Circulation 2006;15:297–299