Expert Review: Valve Disease

A Pilot Project of Familial Screening in Patients with Bicuspid Aortic Valve Disease

Background
BAV is a risk factor for aortic valve disease in adults. It may be the most common cardiovascular malformation, with an estimated incidence of 0.6% to 1.36%.
Previous studies attempted to investigate the hypothesis that clinically asymptomatic BAV may occur at a higher rate in families with a known BAV individual.
Progress in echocardiographic methods over the last decade has made it possible to reevaluate the incidence of valvular anomalies in families of BAV probands with greater confidence and precision. Seeking to investigate the feasibility of running a familial screening, the authors conducted an echocardiographic study of valve morphology and aortic dimensions in relatives of individuals ascertained with BAV.

Knowledge Gap
The recommended approach when an individual is diagnosed of BAV is to carry out a screening of first-degree relatives1,2. The difficulties for firmly establishing this practice are not completely understood:
a) The workload for clinical and echocadiographic departments of this strategy has not been tested. Apart from the number of studies superimposed by the FDR screened, there is the need for long-term surveillance of those who are newly diagnosed with a cardiac abnormality.
b) The diagnosis of a BAV is likely to have psychological and social implications for the individual. This may hamper the availability of FDR to undertake an echocardiographic study

Aim of the Study
The study aimed:
a) To assess the practicability of running a screening program involving FDR of individuals ascertained with BAV
b) To define the prevalence of BAV and aortic abnormalities in FDR patients with BAV.

Methods
This single-center, cross-sectional study included a cohort of patients who had undergone surgery for BAV disease and/or associated aortic dilation. Familial screening (clinical history, physical examination and transthoraric echocardiogram-TTE) was offered to all FDR, with accurate detail regarding the process of screening and the potential implications if they were found to have any valvar or other abnormality. TTE performance and interpretation was carried as per routine practical standards.

Results
A total of 24 probands 75 FDR was recruited. Of these, 23 (30%) FDR were not available or refused the screening.
The prevalence of BAV in FDR was 7.7% (4 cases out of 52 FDR screened). Except for one case (moderate aortic stenosis), valve function was not significantly impaired. Two cases showed dilated aortas.
Within the relatives with tricuspid aortic valve, 2 exhibited dilated aortas.

Conclusion
Various points deserve to be emphasized:
• Routine echocardiographic screening of the FDR of patients who have undergone surgery is feasible from a practical perspective. The actual additional workload for the echocardiography department and clinical follow up service in incorporating this new process might not be an obstacle to implement this strategy.
• The referral and response rate among families is lower than desirable. However, the detection rate among relatives was in keeping with the quoted familial clustering of BAV in other studies to date3-5. However, the selection of BAV patients who had undergone surgery and the low referral and response rate make it difficult to generalize the results to the entire population with BAV. Further research in this field is warranted and establishing a national database of patients with BAV disease will be helpful both for accurate data collection as well as for future research and audit purposes

Clinical Impact:
This pilot study addresses a very important topic on cardiovascular diseases and demonstrates that, from a practical point of view, it is feasible. However, if a BAV familial screening is to be implemented, it should extend to the overall population with BAV (not only those referred for surgery) and include the maximum possible number of relatives. Noteworthy, heritability and risk of recurrence should be addressed, not only from a clinical perspective, but incorporating genetic analysis in routine screening programmes. This could be useful to risk stratification of the index patients and the detection of features that may suggest a higher risk in certain families.

Corresponding author from original paper
Dr. Rosica Panayotova, Department of Cardiology, University Hospital of South Manchester, Southmoor Road, Manchester M23 9LT, UK
e-mail: rpanayotova@yahoo.com

References:
1.- Warnes CA, Williams RG, Bashore TM, et al. ACC/AHA 2008 guidelines for the management of adults with congenital heart disease: A report of the American College of Cardiology/American Heart. Circulation 2008;118:e714-e833
2.- McBride KL, Garg V. Heredity of bicuspid aortic valve: Is family screening indicated? Heart 2011;97:1193-1195
3.- Cripe L, Andelfinger G, Martin LJ, Shooner K, Benson DW. Bicuspid aortic valve is heritable. J Am Coll Cardiol 2004;44:138-143
4.- Huntington K, Hunter AG, Chan KL. A prospective study to assess the frequency of familial clustering of congenital bicuspid aortic valve. J Am Coll Cardiol 1997;30:1809-1812
5.- Robledo-Carmona J, Rodríguez-Bailón I, Carrasco-Chinchilla F, Fernández B, Jiménez-Navarro M, Porras-Martin C, et al. Hereditary patterns of bicuspid aortic valve in a hundred families. Int J Cardiol. 2013 May 16. doi:pii: S0167-5273(13)00847-4. 10.1016/j.ijcard.2013.04.180. [Epub ahead of print]

Citation: The Journal of Heart Valve Disease 2013;22:150

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