Valve-sparing reconstruction of a congenital bicuspid aortic valve with severe calcified aortic stenosis
A GURBUZ, U YETKIN, B LAFCI, B OZCEM, I YUREKLI
aortic stenosis., bicuspid aortic valve, valve-sparing reconstruction
A GURBUZ, U YETKIN, B LAFCI, B OZCEM, I YUREKLI. Valve-sparing reconstruction of a congenital bicuspid aortic valve with severe calcified aortic stenosis. The Internet Journal of Thoracic and Cardiovascular Surgery. 2008 Volume 14 Number 1.
Bicuspid aortic valve is now known to be the most common congenital lesion affecting the human heart. Bicuspid aortic valve is well known to cause calcified aortic stenosis. Valve-sparing reconstruction in cases of bicuspid valves, represents a promising alternative to prosthetic valve replacement. Reconstruction of the bicuspid valve is feasible with good results by the technique of valve repair.
The bicuspid aortic valve affects 1 to 2% of the population and may be complicated by aortic stenosis (1). Aortic valve replacement is the standard procedure in patients with aortic valve pathology. Currently, isolated reconstruction of a regurgitant bicuspid aortic valve can be performed with adequate early results (2). Although long-term results for both biological and mechanical heart valves could be improved, a valve-sparing operation has several advantages especially in young patients (3). In patients with a bicuspid aortic valve, the aortic valvular pathology can be corrected by the valve reconstruction.
Our case was a 10-year-old boy. After his birth he was suffering from intermittent cyanosis of the extremities and the lips. Transthoracic echocardiography revealed a bicuspid aortic valve with severe stenosis where the peak pressure gradient was measured as 60 mm Hg. Left ventricular end-diastolic and end-systolic diameters were measured as 44 and 23 mm, respectively. No aortic regurgitation was identified. Ejection fraction was measured as 83%. Cardiac catheterization revealed no additional pathology.
Our patient was taken to the operating room with these findings. Following a median sternotomy,pericardium was opened longitudinally. After heparinization, extra-corporeal circulation was established between the venae cavae and the ascending aorta. A cross clamp was placed on aorta and by antegrade intermittent isothermic blood cardioplegia from aortic root,cardiac arrest was established.Hypothermia was moderate (29ºc). Standard aortotomy was made. Aortic valve was bicuspid, thickened and calcific in structure. Additionally, the commissures were adhered (Figure 1).
Then, decalcification and commissurotomy were performed (Figure 2).
As the final step, a Hegar dilator of 15 mm was easily passed through annulus (Figure 4).
Postoperative echocardiographic data confirmed complete removal of the aortic valve. The long-term clinical result is excellent.
The bicuspid aortic valve (BAV) is a common congenital cardiac anomaly, having an incidence in the general population of 0.9% to 2.0% and a frequency of 54% in all patients aged >15 years with valvular aortic stenosis. In most cases it remains undetected until infective endocarditis or calcification supervenes (4). This process is associated with increased metalloproteinase activity and apoptosis of vascular smooth muscle cells (1). The bicuspid aortic valve may function normally throughout life, may develop progressive calcification and stenosis (4).
It is estimated that the BAV lesion alone accounts for more morbidity and mortality than all the other congenital cardiac lesions combined. Many authorities feel that this disease is so virulent that every individual with a BAV will, given enough time, develop aortic stenosis, aortic insufficiency or aortic aneurysm/dissection related to the bicuspid valve disease (5). Most patients with a bicuspid aortic valve will develop some complication during life. Individuals with a bicuspid valve may be unaware of its presence and are at risk for unsuspected complications (1).
In the study of Cui et al.; 171 patients with severe aortic valve stenosis underwent aortic valve replacement (AVR). The pathological lesions of the group were bicuspid aortic valve in 26 cases (6).
In the study of Yotsumoto et al.; 374 aortic valve procedures during the past 15 years, 63 cases of bicuspid aortic valve were encountered. Thirty-two patients demonstrated aortic stenosis (AS), 27 aortic regurgitation (AR), and four had both conditions. Patients with AR were significantly younger than those with AS (7).
In the study of Ichihara et al.; of 413 patients undergoing surgery for aortic valve disease, 42 were confirmed to have congenital bicuspid aortic valve. The etiology of the surgical indications in patients with bicuspid valves were degeneration, rheumatic disease. Degenerative aortic stenosis occurred more often in older patients (8).
In young adults with bicuspid aortic valve, age, severity of aortic stenosis, and severity of aortic regurgitation were independently associated with primary cardiac events. Over the mean follow-up duration of 9 years, survival rates were not lower than for the general population (9).
In a bicuspid aortic valve, calcification with stenosis commonly occurs in most older patients. However, in some young adult patients with raphe, AR may result from myxoid degeneration. The presence of raphe in the bicuspid valve appears to have a significant influence on valve hemodynamics (7).
The lack of the necessity of anticoagulation as well as positive hemodynamic factors argue for a valve-sparing surgical technique (3).Timely intervention for bicuspid-related aortic valve disease can preserve both duration of life and quality of life in affected individuals (5). Successful management of severe aortic valve stenosis requires sophisticated surgical techniques and experienced peri-operative care (6).
The person with bicuspid aortic valve requires continuous surveillance to treat associated lesions and prevent complications (1).