Surgical Technique of Preparing Ozaki Valved Conduit and Its Clinical Use as an RV-PA Conduit

The technique of aortic valve reconstruction with neoaortic tricuspidization (Ozaki technique) is relatively well established and studies have shown excellent midterm results. The authors adopted the Ozaki technique to create a valved conduit inside of the Dacron graft (Ozaki valved conduit). They have used the Ozaki valved conduit during total repair of tetralogy of Fallot with type II pulmonary atresia in a 4-year-old girl. The conduit was functioning well during early follow-up.

Clinical History
A 4-year-old girl with a known case of tetralogy of Fallot with type II pulmonary atresia who underwent a modified right BT shunt in 2019 using a 5 mm Goretex graft, presented with dyspnoea on exertion. On examination, she had central cyanosis with room air saturation of around 70%. Shunt murmur was absent. On 2D Echo, diminished flow in the BT shunt with mid-right pulmonary artery and LPA origin stenosis was noted. CT Angiogram showed near-total occlusion of BT shunt with thrombus, which was extending into the right pulmonary artery and its lobar branches. The authors proceeded with taking down the BT shunt, RPA thrombectomy, RPA reconstruction, and VSD closure with Ozaki valved RV-PA conduit

Preparation of Ozaki Valved Conduit
Conduit preparation was commenced at the time of induction. With available readymade Ozaki sizer and bovine pericardium, a 23 mm leaflet was marked on the pericardium and three 23 mm Ozaki leaflets were harvested. As a rule, the authors always take one size smaller graft than the leaflet. Hence, a 22 mm Dacron tube graft was taken. The annulus for the Ozaki leaflet was marked in the graft about 2 cm from the tip of the graft. A 23 mm Ozaki valve sizer was taken. All three commissures and the center point of each cusp were marked on the graft.

The first leaflet was taken. The center point of the leaflet was sutured to the center point of the marked annulus on the graft using 4-0 prolene (4-0 Polypropylene, 8204H, 24 inches, 13 MM, ½ C, Taper, TF needle, Ethicon, USA) and two knots were tied. Initial suturing between leaflet and annulus was in the ratio of 3:1 and as they move along the annulus, it will be in a 1:1 ratio. Leaflets were sutured along the annulus as per marking on the leaflet. Last but one marking was called a doubled dot and it was sutured to the graft perpendicular to the annulus. After the last bite suture was brought outside of the graft and passed through the Teflon felt (5X3 mm). Similarly, the other half of the same leaflet was sutured to the annulus. After the last bite suture was brought outside of the graft and passed through the Teflon felt (5x3 mm). Similarly, the 2nd and 3rd leaflets were sutured to the annulus. An additional commissural suture was taken for each commissure using 4-0 prolene and brought out of the graft and passed through the Teflon felt. (The operative technique is similar to Ozaki neoaortic valve reconstruction.) All the commissural sutures were tied separately. Multiple commissural sutures were taken to support the commissures. The competency of the conduit was checked with saline.

After preparation of the conduit, a redo sternotomy was carried out and the total repair was completed with Ozaki valved conduit. The child had an uneventful postoperative period and was doing well on six months follow-up. The follow-up echocardiogram showed well-functioning Ozaki valved conduit.

Acknowledgement
The authors are grateful to Dr Christopher W.Baird, MD (Associate, Department of Cardiac Surgery, Associate Professor of Surgery, Boston Children Hospital, Harvard Medical School, Boston, USA) for teaching and training them to prepare Ozaki valved donduit.

Reference

Ozaki S, Kawase I, Yamashita H, Shin U, Nozawa Y, Takatoh M, et al. A total of 404 cases of aortic valve reconstruction with glutaraldehyde-treated autologous pericardium. J Thorac Cardiovasc Surg. 2014 Jan;147(1):301-306.

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