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One of the earliest series of aortic valve repair for aortic insufficiency caused by prolapse of bicuspid aortic valve came from the Cleveland Clinic.21 In a series of 94 patients with a mean age of 38 years, the freedom from reoperation was 84% at 7 years.21 The only factor predictive of reoperation was residual aortic insufficiency at the time of repair.21
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The appropriateness of aortic valve repair in patients with incompetent bicuspid aortic valve remains unclear. Competent bicuspid aortic valves appear to be durable because a large proportion of patients who require aortic valve replacement for aortic stenosis in their fifth, sixth, or seventh decades of life are found to have bicuspid aortic valve. Thus, aortic valve repair for incompetent bicuspid aortic valves is a reasonable surgical approach in young adults but the best type of repair remains to be determined. Incompetent bicuspid aortic valves are often associated with dilated aortic annulus and subcommissural plication may be inadequate to prevent future dilation and recurrent aortic insufficiency. A conservative aortic root procedure may be more appropriate for some of these patients.
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Ascending Aortic Aneurysm with Aortic Insufficiency
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We reported our experience with aortic valve repair in patients with ascending aortic aneurysm, normal or minimally dilated aortic sinuses, and moderate or severe aortic insufficiency.22 There were 103 patients whose mean age was 65±12 years and 53% were men. The aneurysm extended into the transverse aortic arch in 60% of the patients and 20% had mega-aorta syndrome. The aortic valve repair consisted in adjusting the diameter of the sinotubular junction in all patients. In addition, repair of cusp prolapse was needed in 36 patients, and replacement of the noncoronary aortic sinus in 8. Associated procedures were: replacement of the transverse aortic arch in 62 patients, coronary artery bypass in 28, and mitral valve repair or replacement in 7. The follow-up was complete at 5.8±2.3 years. There were 2 operative and 30 late deaths. The survival at 10 years was 54±7%. Independent predictors of late death were transverse arch aneurysm, the use of elephant trunk technique to replace the arch and mega-aorta syndrome. Only 2 patients required aortic valve replacement: one for endocarditis and one for severe aortic insufficiency. The freedom from aortic valve replacement at 10 years was 98%. Only one patient developed severe and six developed moderate aortic insufficiency during the follow-up. The freedom from severe or moderate aortic insufficiency at 10 years was 80±7%. These findings suggest that aortic valve repair in these patients is an excellent alternative to valve replacement and the repair remains stable in most patients during the follow-up. Late survival was suboptimal because of the extensiveness of the vascular disease.
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We reported our current experience with aortic valve sparing operations for aortic root aneurysm in 220 patients.23 Their mean age was 46±15 years, 78% were men and 40% had the Marfan syndrome. In addition, 17% had type A aortic dissection, 7% had bicuspid aortic valve, and 22% had transverse arch aneurysm. Previous replacement of the ascending aorta had been done in 10 patients and the Ross procedure in 2. Sixteen patients had severe mitral insufficiency. Approximately one-half of the patients had moderate or severe aortic insufficiency before surgery. The technique of remodeling of the aortic root was used in 53 patients and the reimplantation of the aortic valve in 167. The follow-up was complete at 5.2±3.7 years. All patients had echocardiographic studies during the follow-up. There were 3 operative and 13 late deaths. Patients' survival at 10 years was 88±3% and was similar to that of the general population of Ontario. Age greater than 65 years, advanced functional class, and ejection fraction less than 40% were independent predictors of death. Seven patients developed moderate and 5 developed severe aortic insufficiency. Overall freedom from moderate or severe aortic insufficiency at 10 years was 85±5%, but it was 94±4% after reimplantation of the aortic valve and 75 ±10% remodeling of the aortic root (p = 0.04). Five patients required aortic valve replacement; the freedom at 10 years was 95±3%. One patient developed endocarditis 11 years postoperatively, and 8 suffered thromboembolic events. At the latest follow-up 88% of the patients were in functional class I, and 10% were in class II. These findings suggested that reimplantation of the aortic valve provides more stable aortic valve function than remodeling of the aortic root.
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Yacoub et al.24 who used exclusively the remodeling of the aortic root to treat 158 patients with aortic root and ascending aortic aneurysms, reported a freedom from aortic valve replacement of 89% at 10 years, and moderate aortic insufficiency in one-third of the patients.
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Aicher et al.25 who also used the remodeling of the aortic root in 274 patients (mean age 59±15 years, 193 tricuspid and 81 bicuspid valves) reported a freedom from aortic insufficiency grade II or greater of 91% for bicuspid and 87% for tricuspid at 10 years, and a freedom from aortic valve replacement of 98% at 5 and at 10 years.
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We recently reported the long-term results with aortic valve sparing operations in patients with Marfan syndrome.26 A cohort of 103 consecutive patients with Marfan syndrome with a mean age of 37±12 years underwent either remodeling of the aortic root (26 patients) or reimplantation of the aortic valve (77 patients) and were prospectively followed for a mean of 7.3±4.2 years with annual echocardiography. The survival at 15 years was 87.2%, somewhat lower than the 95.6% for the general population largely because of complications of aortic dissection. The freedom from aortic insufficiency greater than mild was 79.2%. Only 3 patients required aortic valve replacement, two for aortic insufficiency and one for endocarditis.
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There are several reports on early clinical and hemodynamic outcomes on these two types of aortic valve sparing procedures.27-30 Most comparative studies suggest that the reimplantation of the aortic valve provides a more stable aortic valve function than the remodeling of the aortic root, particularly in patients with dilated aortic annulus, Marfan syndrome, and acute type A aortic dissection. Hemodynamic studies suggest that cusp motion and flow patterns across the reconstructed aortic root are more physiologic after remodeling of the aortic root than reimplantation of the aortic valve.29 In patients who had the reimplantation procedure, flow patterns and cusp motion are better with neoaortic sinuses than without.30 However, in our series of reimplantations of the aortic valve, there was no difference in aortic valve function after 10 years in patients with a straight tube or with neoaortic sinuses. Aortic sinuses seem to decrease the mechanical stress on the aortic cusps but it is not clinically apparent during the first decade of follow-up as far as durability of the procedure.
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Aortic valve sparing operations may be inappropriate for young children because of future mismatch between the size of the graft and somatic growth.
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Another important question regarding aortic valve sparing operations is whether they are better than the Bentall procedure with mechanical valves. There has been no randomized clinical trial comparing these two procedures for the treatment of aortic root aneurysms or ascending aortic aneurysm but retrospective studies in patients with Marfan syndrome suggest that the outcomes may be similar.
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We believe that aortic valve sparing operations offer an ideal method for treating patients with aortic root aneurysm and normal or minimally diseased aortic cusps. When correctly performed, they provide excellent results and are associated with very low rates of valve-related complications. However, because they are technically demanding operations, only surgeons with extensive experience in aortic surgery should perform them. The surgeon must have a sound knowledge of anatomy and pathology of the aortic valve and be able to apply the concepts of functional anatomy to create an anatomically and functionally satisfactory new aortic root.