A new aortic root prosthesis with compliant sinuses for valve-sparing operations.

BACKGROUND: We designed and tested a novel aortic root prosthesis with compliant sinuses for valve-sparing operations. METHODS: In eight human aortic roots, the aorta was trimmed 2 mm above the leaflet attachment. The aortic portion of the graft was made by scalloping the Dacron tube. Three sinuses were made individually after turning z-folds in the fabric 90 degrees. Three rectangular pieces were cut and purse strings sewn in each to form the sinuses. The graft was sutured to the aortic root and studied in a left heart simulator. The leaflet motion was recorded (500 frames/second), commissural movement was measured with ultrasound, and the shape of the root was determined from a mold. Seven intact aortic roots were also studied. RESULTS: In the aortic graft roots, the valves were competent and leaflets opened rapidly into a circular orifice, not touching the sinus wall. Commissural diameter increased by 22% when pressure increased from 0 to 80 mm Hg, and increased by a further 6.6% when pressure increased to 120 mm Hg. The sinuses had a teardrop shape. CONCLUSIONS: The dynamics of the aortic graft root and the leaflets were comparable to that of the intact aortic root. This prosthesis is being introduced in clinical practice.

Influence of sizing and subcoronary implantation technique on the function of porcine aortic homografts.

The function and longevity of the homograft aortic valve may be influenced by valve size and subcoronary implantation technique. Dynamic function and leaflet configuration of the porcine aortic valve were analysed first in its natural root in a left heart simulator using glycerol at 120/80 mm Hg pressure and 4 l min-1 Cardiac Output (C.O.). Then the valve was implanted in the porcine root and studied: Group I (n = 4) 1-2 mm smaller, Group II (n = 8) 3-4 mm smaller and Group III (n = 4) 5-7 mm smaller donor valve than the recipient. A silicone rubber mould of the implanted valve was made and analysed. In the donor aortic root the commissural expansion for 0 to 80 mm Hg pressure was 42% which was reduced significantly in all assemblies. Group I showed the largest decrease in the orifice area (OA). In Group III decrease in the OA was less, however, two of the four valves had aortic insufficiency (AI). In Group II decrease in the OA was only 13% and there was no AI. During opening the leaflet surface was smooth and free of wrinkles in the intact valve, but had creases and folds in all three groups. All implanted valves had an indentation along the suture line disrupting the leaflet-sinus continuity. Hence, to enhance valve longevity, donor valve 3-4 mm smaller than the recipient should be chosen and the implantation technique modified to preserve the leaflet-sinus continuity.

Clinical introduction of a novel prosthesis for valve-preserving aortic root reconstruction for annuloaortic ectasia.

OBJECTIVE: Most patients with annuloaortic ectasia are young. They are at risk for complications related to a lifetime of anticoagulation when composite grafts containing mechanical valves are used for reconstruction. The majority of patients have near normal valve cusps. Valve-preserving techniques have been developed to maintain valve function and avoid anticoagulation. The eddy currents occurring within the sinuses of Valsalva in the natural aortic root have been shown to be important in the smooth, gradual, and gentle closure of the valve. Compliance of the sinuses is important in reducing stress in the leaflets. A novel ascending aortic prosthesis with "built in" compliant sinuses (Robicsek-Thubrikar graft) was developed for clinical aortic root replacement. METHODS: Woven Dacron tubes were used to make the prostheses. Three precisely measured square pieces were cut to make the expandable, individual sinuses. Sewing the individual neo-sinuses to a scalloped end of the Dacron tube graft created the neo-sinotubular junction and sinotubular ridge. Five patients with annuloaortic ectasia underwent valve-preserving aortic root reconstruction. RESULTS: All intraoperative transesophageal echocardiographic images after the valve-preserving procedure showed a normal appearing root with 10% radial expansion of each sinus in systole. The space between the cusps and neo-sinus wall in systole was normal. No patient has more than mild aortic regurgitation. CONCLUSIONS: Valve-preserving aortic root reconstruction with a novel Dacron prosthesis with compliant "built in" sinuses re-establishes normal aortic root geometry with near normal valve motion. This may enhance the durability of the valve-preserving operation.

The influence of sizing on the dynamic function of the free-hand implanted porcine aortic homograft: an in vitro study.

BACKGROUND AND AIMS OF THE STUDY: The influence of sizing on the function of a porcine aortic valve after its implantation using the free-hand technique in the subcoronary position was investigated. METHODS: Dynamic function and leaflet configuration of the valve (n = 16) were first analyzed in its natural aortic root in a left heart simulator at 120/80 mmHg pressure and 4 l/min cardiac output. The valve was then implanted in the recipient porcine aortic root and re-studied. Three groups were investigated: group I (n = 4) comprised of 1-2 mm smaller donor aortic valve than the recipient; group II (n = 8) 3-4 mm smaller; and group III (n = 4) 5-7 mm smaller. Orifice area (OA), systolic and diastolic configurations of the leaflets, pattern and timing of leaflet opening and closure, commissural movement, pressure gradient and valvular regurgitation were analyzed. RESULTS: In the intact donor aortic root, average expansion of the aorta at the commissures, for a pressure change from 0 to 80 mmHg, was about 42%. This was reduced significantly in all assemblies. Group I showed a 34% reduction in OA, and excessive leaflet bending; there was no aortic insufficiency (AI) or pressure gradient across the valve. In group III there was a lesser reduction in OA and reduced leaflet bending, but two of four valves had AI. In group II, the reduction in OA was only 13%, there was less leaflet bending, and no AI. CONCLUSIONS: The donor valve 3-4 mm smaller than the recipient seems an optimal match. The current practice of using the same size donor as recipient may be responsible for excessive leaflet bending and may be implicated in early deterioration of the homograft.