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IMAGES IN CARDIAC SURGERY
A Quadricupsid Aortic Valve Jagdish Butany, M.B.B.S., M.S., F.R.C.P.C.,∗ ¶ Michael J. Collins, B.Sc.,∗ Michael Duchnay, B.Sc.,∗ Dina El Demellawy, M.D., Ph.D.,∗ Jacek Karski, M.D.,† and Anthony C. Ralph-Edwards, M.D., F.R.C.S.C.‡¶ ∗
Department of Pathology, †Department of Anesthesia, ‡Department of Cardiac Surgery, ¶Toronto Medical Laboratories, University Health Network and University of Toronto, Toronto, Ontario, Canada
(J Card Surg 2005;20:193-197)
Quadricuspid aortic valves (QAV) are rare congenital anomalies of unknown morphogenesis, often associated with the development of significant aortic valve dysfunction in adulthood. Once largely an incidental finding at necropsy or rarely at surgery, cases of QAV are now more frequently diagnosed preoperatively, following recent advances in echocardiography.1 The Address for correspondence: Jagdish Butany, M.B.B.S., M.S., F.R.C.P.C., Department of Pathology E4-322, Toronto General Hospital, Toronto, ON, M5G 2C4. Fax: 416-340-4213; e-mail:
[email protected]
combined incidence of QAV at autopsy and echocardiography indicates good concordance of results, with an estimated QAV frequency of approximately 0.013%, with a total of 129 cases reported in the literature.2 Although nontricuspid semilunar valves are not uncommon, quadricuspid valves are the rarest of the abnormalities with the bicuspid being the most common. The incidence of QAV is five times less than quadricupid pulmonary valves (QPV).2 We report a case of a Type F QAV (two equal larger cusps, two unequal smaller cusps—Hurwitz and Roberts3 classification) in a 64-year-old man.
Figure 1. Transesophageal echocardiogram (TEE) showing severe aortic insufficiency. LA = left atrium, LV = left ventricle, RV = right ventricle.
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Figure 2. A representative TEE of a QAV (panel A) taken from another case showing a gap between the closed cusps (white asterisk) and normal tricuspid valve (panel B) during diastole. Arrowheads = cusp leaflets, LA = left atrium, RA = right atrium, RV = right ventricle.
CLINICAL SUMMARY A 64-year-old man with a history of coronary artery disease (CAD) affecting the left main and left anterior descending coronary arteries (angioplasty four years ago) was admitted for coronary artery bypass grafting (CABG) and aortic valve replacement (AVR). The patient had a blood pressure of 125/60 mmHg, a heart rate of 52 beats/min, and a respiratory rate of 20 breaths/min. Transthoracic echocardiography (TTE) was consistent with aortic valve insufficiency with mild aortic stenosis (Fig. 1). Aortic valve area was estimated at 1.5 cm2 . At surgery, the aortic valve was found to be quadricuspid (Figs. 2 and 3). The aortic leaflets were slightly thickened with decreased mobility of the leaflets. The
valve was replaced with a bileaflet mechanical heart valve prosthesis. The patient had a smooth postoperative course and was discharged on day 6 after surgery. PATHOLOGY The specimen submitted consisted of a single circular piece of tissue with four cusps and commissures, two of which were intact (Fig. 4). The cusps were of varying sizes: 2.5 cm × 1.6 cm, 2.4 cm × 1.5 cm, 2.2 cm × 1.3 cm, and 1.8 cm × 1.3 cm, respectively. All four cusps showed fibrosis, thickening, and stiffening. The thickening was located mainly at the rough zones with nodules on the flow surface. Focal areas of calcification were present in some of the cusps. Lipid
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Figure 3. A representative TEE of a QAV (panel A) taken from another case and normal tricuspid valve (panel B) during systole. Cusp leaflets are marked by arrowheads. LA = left atrium, RA = right atrium, RV = right ventricle.
insudation was present in all four cusps. Two of the four commissures showed a mild degree of fusion, most pronounced in the region of the commissure between the smallest and the adjacent cusp (Figs. 4, 5, and 6). This region also had a large fenestra near the base of the commissure. Gross examination suggests that this fenestra, measuring approximately 1.2 cm in length by 0.7 cm, is not a perforation, but merely a fenestration so that the sinuses of the two cusps were nearly continuous. Nevertheless, commissural regions above and below this defect suggest that this is a true commissure.
CONCLUSION This aortic valve was identified as a quadricuspid valve by the presence of four commissures and the presence of four nodules of Arantius. Other gross morphological features supported and confirmed the finding of Type F QAV. Although the embryology of human quadricuspid aortic valves remains unknown, several incidental cases of QAV have recently been reported in embryological animal studies that would seem to contradict the classical hypotheses on the formation of QAV in man.4
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Figure 4. A view of the nonflow (aortic) surface of the quadricuspid aortic valve with four intact leaflets showing thickening of the cusps near the free margin (white arrows) and mild fusion of two commissures (black arrows). The other two commissures (black arrow heads) show only mild cusp fibrosis.
Figure 5. Transverse section of all four cusps showing cusp fibrosis and thickening. The presence of four cusps was documented by the presence of four nodules of Arantius (arrows). The commissures were difficult to demonstrate on histologic sections. Stain: Movat pentachrome (original magnification ×1.0).
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Figure 6. A view of the flow (ventricular) surface of the quadricuspid aortic valve with four intact leaflets showing mild fusion of two commissures (arrows). The other two commissures (arrow heads) show only mild cusp fibrosis.
QAV is a relatively rare cause of aortic valve disease. A majority of QAV are found to have a higher incidence of aortic insufficiency (AI), the exception being Type E (three equal cusps, one larger cusp).3 Significant AI does not normally present until adulthood, often requiring AVR in the fifth or sixth decades. Echocardiographic examination usually identifies the AI, but not the QAV per se. Patients with QAV and severe AI by echocardiography should be screened for coronary artery ostial abnormalities to prevent occlusion of the ostia by the prosthetic valve at the time of valve replacement surgery.1 Because of the potential risk of infective endocarditis, antibiotic prophylaxis is advised for patients identified with QAV undergoing surgery.5 Current sporadic case studies do not indicate a relation between the frequency of valve dysfunction in QAV and valve morphology. Larger series of cases are needed to determine the mechanisms
of valve dysfunction in congenitally abnormal aortic valves. REFERENCES 1. Timperley J, Milner R, Marshall AJ, et al: Quadricuspid aortic valves. Clin Cardiol 2002;25:548-552. 2. Hwang DM, Feindel CM, Butany JW: Quadricuspid semilunar valves: Report of two cases. Can J Cardiol 2003;19(8):938-941. 3. Hurwitz LE, Roberts WC: Quadricuspid semilunar valve. Am J Cardiol 1973;31:323-326. 4. Fernandez B, Duran AC, Martire A, et al: New embryological evidence for the formation of quadricuspid aortic valves in Serian hamsters (Mesocricetus auratus). J Comp Path 1999;121:89-94. 5. Takeda N, Ohtaki E, Kasegawa H, et al: Infective endocarditis associated with quadricuspid aortic valve. Jpn Heart J 2003;44(3):441-445.
