Ann Thorac Cardiovasc Surg Vol 8 No 5 2002 - PDF document

Ann Thorac Cardiovasc Surg Vol. 8, No. 5 (2002) IntroductionThe bicuspid aortic valve is a common congenital car-diac anomaly, having an incidence in the general popula-tion of 0.9 to 2.0% and a frequency of 54% of all patientsag�ed 15 years with valvular aortic stenosis. It was first From Department of Anatomy, Hacettepe University, Faculty of Bicuspid Aortic ValveAnn Thorac Cardiovasc Surg Vol. 8, No. 5 (2002)patients with a bicuspid aortic valve (29-56.8%) and in The ignorance of these associationsmay cause an inadequate myocardial preservation and anincreased risk of myocardial infarction.The genetics of bicuspid aortic valves have been studiedby several investigators. These valves may run in fami-lies in a multifactorial inheritance pattern or occasionallyin an autosomal dominant one. Emanuel et al. have founda minimum family incidence of 14.6% of bicuspid aorticvalves. In a recent study of first degree relatives of in-dividuals with bicuspid aortic valves, the prevalance ofthis defect was found to be 9.1%, which was well abovethe estimated population prevalance of 1-2%. Althoughthese valves are more common in males than females bya factor of 2:1 in the general population, the prevalancewas equal in males and females in families having morethan one affected individual.The recognition of the bicuspid aortic valve in patientswith aortic valve disease remains an important challenge The reliability of the diagnosis has beensignificantly improved by the introduction of cross sec-tional and Doppler echocardiography. Diagnosis isbased on the demonstration of two cusps and two com-missures during short axis visualisation. Supportive fea-tures include cusp redundancy and eccentric valve clo-sure, and a single coaptation line between the cusps dur- Although in patients with adequate trans-thoracic echocardiograms, a sensitivity and specificity of78 and 96%, respectively, for the identification of a bi-cuspid aortic valve have been reported, in up to 25% ofpatients, morphology of the aortic valve cannot be deter-mined by transthoracic echocardiography. In a recentstudy, Espinal and colleagues have reported their experi-ence with transesophageal echocardiography shows a highdegree of sensitivity and specificity for determining aor-tic valve morphology, especially when using the multi-The congenitally bicuspid valve may function normallythroughout life, may develop progressive calcification andstenosis or may develop regurgitation with or without in- The natural history of this valve is of calcifica- The congenital variety of aortic stenosis is themost common, and accounts for two-thirds of thenonrheumatic patients. Severely stenosed bicuspid aor-tic valves are very rigid because of fibrosis and heavycalcification, but are not narrowed. Both calcificationand fibrosis are age related. Most patients with a bicus-pid aortic valve have abnormal valvular calcification bythe age of 20, and nearly al

l show calcification by 30 yearsFig. 1. The bicuspid aortic valve of a 40-year-old malepatient who underwent aortic valve replacement with aaortic stenosis and regurgitation with a gradient of 80mmHg. Arrow shows the raphe or false commissure. Yener et al.Ann Thorac Cardiovasc Surg Vol. 8, No. 5 (2002) Stenosis progresses more rapidly (27 mmHgthe anteroposterior location. Patients with aortic steno-sis secondary to a bicuspid aortic valve were found torequire aortic valve replacement five years before thosewith a tricuspid valve.The incidence of aortic regurgitation secondary to bi-cuspid aortic valves was reported to be 1.5 to 3%. Itthe larger of the cusps, but also in association with aorticroot dilatation, coarctation of the aorta, or infective en- Pachulski et al. found that the aortic rootdiameter was significantly larger among patients with bi-cuspid aortic valves than among normal controls, even inthe absence of hemodynamically significant aortic steno- Disruption or dissolution of elastic tissue withingurgitation. Infective endocarditis is responsible forbetween 43 and 60% of cases of severe aortic regurgita-tion in patients with a bicuspid aortic valve, the result ofInfective endocarditis is a well-recognized complica-tion of a bicuspid aortic valve; autopsy evidence suggeststhe fourth and fifth decade of life, requiring major sur-gery in most cases, with significant mortality (9%).Bicuspid aortic valve endocarditis predominantly occurs(73-100%). The mean age in the adult series varies be-tween 38 and 53 years. Staphylococci and viridansstreptococci have accounted for nearly three-quarters ofthe cases, as in native valve endocarditis. Complications,especially heart failure and valvular or myocardial ab-scesses are common. Most patients require surgery, oftenon an emergency basis. Recent surgical series show that25 to 54% of all infected aortic valves are bicuspid.Bicuspid aortic valves are likely to become the most im-portant intrinsic cardiac predisposition for infective en-fever in the developed countries.A bicuspid aortic valve is present in 7 to 13% ofunselected cases of aortic dissection. The risk of dis-section in patients with bicuspid aortic valves is reportedto be nine times higher. Aortic dissection usually oc-curs in the presence of a normally functioning valve, butit may also occur with stenosed bicuspid aortic valvesand following aortic valve replacement, at a site remotefrom surgical access to the valve. Abnormalities invalves, specifically premature medial layer smooth musclecell apoptosis, have been described, explaining the higher-than-expected prevalance of aortic dissection in these Also morphometric studies show less elastictissue in the aortas of bicuspid aortic valve patients.These findings may one day make it advisable to con-sider replacement of the ascending aorta when valve re-aortic valve.Congenital bicuspid aortic valves are common and in mostcases remain

undetected until infection or calcificationsupervenes. Aortic stenosis and regurgitation, infectivecomplications. The recognition of the bicuspid valve inpatients with aortic valve disease remains an importantchallenge to the clinician, whereas preoperative knowl-edge of valve morphology would be helpful in planningthe surgery. Echocardiography should be undertaken insibly also in the first- and second-degree relatives of pa-tients with known bicuspid aortic valves. Antibioticprophylaxis for infective endocarditis is also recom-References1.Hammond GL, Letsou GV. Aortic valve disease andhypertrophic cardiomyopathies. In: Baue AE ed.;GlennÕs Thoracic and Cardiovascular Surgery. Con-necticut: Appleton & Lange, 6th ed. 1996; pp 1981Ð2.Osler W. The bicuspid condition of the aortic valves.Transactions of the Association of American Physicians3.Clarke DR, Bishop DA. Congenital malformations ofthe aortic valve and left ventricular outflow tract. In:Baue AE ed.; GlennÕs Thoracic and CardiovascularSurgery. Connecticut: Appleton & Lange, 6th ed. 1996;4.Pomerance A. Pathogenesis of aortic stenosis and its5.Roberts WC. The congenitally bicuspid aortic valve.Am J Cardiol6.Peacock TB. Valvular Disease of the Heart. London:7.Olson LJ, Subramanian R, Edwards WD. Surgical pa-thology of pure aortic insufficiency: a study of 225Mayo Clin Proc8.Ward C. Clinical significance of the bicuspid aorticvalve. Heart Bicuspid Aortic ValveAnn Thorac Cardiovasc Surg Vol. 8, No. 5 (2002)9.Stewart AB, Ahmet R, Travill CM, et al. Coarctationof the aorta, life and health 20-44 years after surgicalrepair. Br Heart J: 65Ð70.10.Presbitero P, Demarie D, Villani M, et al. Long termresults (15-30 years) of surgical repair of aortic coarc-11.Roberts WC, Morrow AG, Braunwald E. Complete in-terruption of the aortic arch. Circulation 1962; : 39Ð12.Hutchins GM, Nazarian IH, Bulkley BH. Associationof left dominant coronary arterial system with congeni-tal bicuspid aortic valve. Am J Cardiol 1978; : 57Ð9.13.Higgins CB, Wexler L. Reversal of dominance of thecoronary arterial system in isolated aortic stenosis andbicuspid aortic valve. Circulation14.Gelb BD, Zhang J, Sommer RJ, Wasserman JM,Reitman MJ, Willner JP. Familial patent ductus arte-riosus and bicuspid aortic valve with hand anomalies:a novel heart-hand syndrome. 15.Emanuel R, Withers R, OÕBrien K, Ross P, Feizi O.Congenitally bicuspid aortic valves: clinicogeneticstudy of 41 families. Br Heart J16.Huntington K, Hunter AG, Chan KL. A prospectivestudy to assess the frequency of familial clustering ofcongenital bicuspid aortic valve. J Am Coll Cardiol17.Clementi M, Notari L, Borghi A, Tenconi R. Familialcongenital bicuspid aortic valve: a disorder of uncer-tain inheritance. 18.Espinal M, Fuisz AR, Nanda NC, Aaluri SR, MukhtarO, Sekar P. Sensitivity and specificity of transeso-phageal echocardiography for determination of aorticvalve morphology. Am Heart J19.Weyman AE, Griffin BP. Left

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