Introduction

Currently, the Bentall-DeBono procedure is the “gold standard” for surgical treatment of patients with aortic valve disease and aortic root aneurysm. Hugh Bentall and Anthony DeBono first described this surgery in 1968 [1]. In most cases, valved conduits contain mechanical prostheses requiring lifelong anticoagulation and increasing the risk of bleeding [2].

Aortic valve replacement with biological prostheses is common in open aortic valve surgery, especially in elderly patients [3].

To date, a few valved conduits with biological prostheses are available for Bentall-DeBono procedure. The most available ones are Vascutek BioValsalva graft (Vascutek Terumo, Renfrewshire, UK) and Sorin Mitroflow Valsalva graft (Sorin Group, Milan, Italy) [4, 5].

Among national manufacturers of artificial heart valves, valved conduits with biological prostheses are limited. The TiAra biological prosthesis has been used in clinical practice since 2018. It is a stented bovine pericardial valve designed for supraannular position (ZAO NeoKor, Kemerovo, Russia). The peculiarity of this prosthesis is combination of advantages of stented and stentless biological prostheses. The valve has a flexible frame from shape memory nitinol wire covered by bovine pericardium [6, 7].

In this report, we present surgical experience of 5 Bentall-DeBono procedures using TiAra biological aortic valve prosthesis. Preoperative transthoracic echocardiography data are presented in the Table.

Preoperative transthoracic echocardiography data

Note. LV EF — left ventricular ejection fraction.

Implantation technique

We used antegrade selective or non-selective cardioplegia for myocardial protection (Custodiol 2000 ml, Custodiol Dr Kohler Pharma, Alsbach-Hahnlein, Germany) depending on severity of aortic regurgitation. After cardioplegia, we excised the wall of ascending aorta and sinuses of Valsalva, aortic valve. Coronary ostia were mobilized. We used special sizers for measurement of aortic annulus before replacement. Aortic prosthesis size depended on baseline diameter of aortic annulus. We preferred the largest possible size of prosthesis.

Implantation of biological prosthesis “TiAra” with ascending aorta replacement (hand-made method)

The feature of this technique is fixation of biological prosthesis to the linear vascular prosthesis before implantation of vascular graft. At the first stage, TiAra biological prosthesis was fixed to the linear vascular prosthesis by continuous monofilament suture 5/0. After assessing the biological prosthesis, proximal anastomosis was formed between the valved conduit and aortic annulus by continuous monofilament suture 4/0. Then, coronary ostia were sequentially implanted into vascular prosthesis by continuous monofilament suture 5/0, and distal anastomosis was formed between the aorta and vascular prosthesis.

Modified technique of implantation of biological prosthesis “TiAra” with ascending aorta replacement

After the above-mentioned manipulations (preparation of aortic root, coronary ostia, excision of sinuses of Valsalva), a linear vascular prosthesis was fixed to aortic annulus by continuous monofilament suture 4/0. Three the deepest equidistant points (suggested nadirs) and projections of commissure tops were marked by a medical marker inside the linear vascular prosthesis for subsequent implantation of artificial prosthesis. Then, we implanted the left and right coronary ostia using continuous suture. After implantation of coronary ostia, three U-shaped monofilament sutures 4/0 were passed through the marked points (primary fixation point). Then, we sutured vascular prosthesis using these sutures in the deepest zones of xenopericardial prominence of bioprosthesis. After that, we continued suturing the vascular prosthesis and aortic valve prosthesis in opposite directions towards commissure tops. After lowering the biological prosthesis to the vascular graft, we continued fixation by continuous suture to projections of commissure tops. After complete fixation of prosthesis, we tied sutures outside the vascular prosthesis and formed distal anastomosis between the aorta and vascular prosthesis (Figure).

Modified aortic valve and ascending aortic replacement using the TiAra bioprosthesis.

a — the first stage: fixation of vascular prosthesis to the aortic annulus; b — the second stage: reimplantation of coronary ostia to vascular prosthesis; b — the third stage: implantation of biological semistented prosthesis into the linear vascular graft.

Intraoperative results

There was no intraoperative mortality. The median time of cardiopulmonary bypass was 168 [161; 287] min, aortic cross-clamping — 141 [127; 233] min.

All patients underwent the Bentall-DeBono procedure using TiAra 25 mm bioprosthesis and Vascutek Gelweave Stretch 28 mm linear vascular graft (VASCUTEK, TERUMO Company Newmains Avenue, Scotland, UK). Open distal anastomosis (hemiarch procedure) under hypothermic circulatory arrest and bilateral cerebral perfusion was additionally performed in 1 patient. One patient underwent bio-Bentall-DeBono procedure total aortic arch replacement (branched vascular prosthesis Vascutek Siena Plexus 28), tricuspid valve repair, edge-to-edge mitral valve repair, coronary artery bypass grafting of the right coronary artery.

Re-occlusion of the aorta was required in one case. Control transesophageal echocardiography revealed para-prosthetic fistula on the aortic valve. This fistula was sutured by continuous suture with satisfactory hemodynamic result.

Postoperative period

There was no in-hospital mortality. No postoperative bleeding requiring exploration was observed.

One patient with dysfunction of mechanical prosthesis following infective endocarditis and aortic root abscess near conduction pathways required implantation of two-chamber pacemaker. This patient had baseline transient second-degree atrioventricular blockade.

Length of hospital-stay was 16 [12; 23] days, peak and mean pressure gradients — 21 [14; 27] and 14 [7; 18] mm Hg, respectively. All patients had no severe transprosthetic and paraprosthetic regurgitation.

Discussion

Over the past few decades, elderly patients prevail in cardiac surgery. This fact increased the incidence of implantation of biological prostheses. Many patients with aortic valve disease sometimes require aortic root replacement. Bentall-DeBono procedure is preferable in these patients. Most valved conduits contain mechanical prostheses. In this regard, cardiac surgeons have to perform bio-Bentall-DeBono procedure and prepare valved conduit from separate elements (biological prosthesis and vascular graft). This prolongs aortic cross-clamping and cardiopulmonary bypass [8].

The main problem for biological valved conduits is different environment for storing the vascular prosthesis and biological valve. As is known, preservation and sterilization of bioprosthesis are carried out in a liquid medium. Dacron vascular prosthesis must be stored in dry environment, since liquid medium damages gelatin-collagen layer and increases porosity of prosthesis. Thus, development of a second-generation Dacron valved conduit with bioprosthesis is currently associated with technical difficulties [9].

In the early 2000s foreign medical manufacturers presented the following biological valved conduits: third-generation Vascutek BioValsalva graft (Vascutek Terumo, Renfrewshire, UK) and Sorin Mitroflow Valsalva conduit (Sorin Group, Milan, Italy).

The BioValsalva valved conduit is a Triplextrade third-generation Dacron vascular graft (Terumo Vascutek, Renfrewshire, Scotland, UK) with stentless bioprosthesis (Elan, Vascutek Terumo). Proximal part of this conduit imitates aortic root in the form of sinuses of Valsalva. The conduit itself has a three-layer structure (inner part — Dacron, outer part — polytetrafluoroethylene, central part — binding membrane with zero porosity). Stentless bioprosthesis simplifies redo replacement for degeneration of bioprosthesis. However, there are questions regarding valve-in-valve transcatheter aortic valve implantation (TAVI) due to stentless design of the valve [4].

The main advantage of the Sorin Mitroflow Valsalva valved conduit (Sorin Group, Milan, Italy) is separate storage of each element of this conduit. Sorin Mitroflow stented bioprosthesis is easily implanted into the Valsalva vascular graft during surgery and fixed by tying a thread. Sorin Mitroflow Valsalva conduit demonstrates effective clinical and hemodynamic immediate results. However, data on long-term results after implantation of this conduit are very limited [5, 10]. Sorin Mitroflow bioprosthesis confirmed own effectiveness for aortic valve defects over many years of research. Some studies demonstrated favorable results of TAVI after implantation of Sorin Mitroflow stented bioprosthesis [11-13].

We report Bentall-DeBono procedure using TiAra bioprosthesis. The design of nitinol stent with shape memory significantly simplifies implantation and reduces the time of aortic cross-clamping and cardiopulmonary bypass. We presented implantation of hand-made valved conduit and modification of aortic root replacement when implantation of vascular graft is followed by implantation of bioprosthesis. Both techniques of ascending aorta replacement allow the prosthesis to be securely fixed to the linear vascular graft. Moreover, we can implant the largest bioprosthesis. In our opinion, modified technique of Bentall-DeBono procedure with TiAra bioprosthesis has certain advantages. Firstly, fixation of flexible vascular prosthesis by continuous suture is technically easier and faster compared to hand-made valved conduit, since the base of TiAra prosthesis has a crown-like shape rather linear one like in stented prostheses. Secondly, this is especially important in case of redo aortic root replacement (dysfunction of prosthesis or graft) or aortic annulus destruction (infective endocarditis or aortic root abscess). In these patients, we have to fix the vascular graft to aortic root rather native aortic annulus. Thirdly, implantation of coronary ostia before fixation of aortic prosthesis somewhat simplifies surgical technique. We do not exclude the possibility of TAVI in patients with degeneration of bioprosthesis considering design features (nitinol stent) of TiAra bioprosthesis.

Thus, Bentall-DeBono procedure with TiAra bioprosthesis eliminates aortic valve defects in patients with ascending aortic aneurysm. This surgery demonstrates favorable clinical and hemodynamic results with low in-hospital incidence of prosthesis-related complications.

Conflict of interest

The study was supported by the grant of the President of the Russian Federation No. 075-15-2022-823.

The authors declare no conflicts of interest.