Interact CardioVasc Thorac Surg 2008;7:1062-1066. doi:10.1510/icvts.2008.187849
© 2008 European Association of Cardio-Thoracic Surgery
Institutional report - Vascular thoracic |
Bio-ValsalvaTM prosthesis: ‘new’ conduit for ‘old’ patients
Roberto Di Bartolomeo,
Luca Botta,
Alessandro Leone,
Emanuele Pilato,
Sofia Martin-Suarez,
Massimo Bacchini and
Davide Pacini*
Department of Cardiac Surgery, University of Bologna, Policlinico S.Orsola-Malpighi, via Massarenti 9, 40138 Bologna, Italy
Received 9 July 2008;
received in revised form 29 August 2008;
accepted 1 September 2008
Corresponding author. Tel.: +39-051-6363361; fax: +39-051-345990.
E-mail address: dpacini{at}hotmail.com (D. Pacini).
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Abstract
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A new bio-prosthetic valved conduit (Bio-ValsalvaTM) has recently been introduced into surgical practice in order to offer a valid option for elderly patients undergoing composite aortic root replacement. The conduit is made up of a stentless porcine valve (elan valve) pre-sewn inside a triple layer Valsalva prosthesis and it is entirely preserved in a glutaraldehyde solution. In our Department, 21 patients (16 males, mean age 67.8±5.5 years) underwent aortic root replacement using the Bio-ValsalvaTM prosthesis. Composite root replacement was extended to the hemiarch in three cases while a complete arch replacement was performed in two patients. Type A aortic dissection was present in two cases while a bicuspid aortic valve was detected in eight patients. In-hospital mortality was 4.7% (1 patient). Re-thoracotomy for bleeding was performed in one case. The median in-hospital stay was 12 days. The median follow-up was six months and is 100% complete. There were no re-operations or structural deterioration during this early phase of observation. The Bio-ValsalvaTM graft, readily available in different sizes, demonstrates ease of implantability and shows good haemostatic characteristics. More patients and a longer follow-up are necessary to confirm the advantages of this graft.
Key Words: Aortic root aneurysm; Stentless aortic valve; Aortic root replacement
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1. Introduction
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Composite aortic root replacement with direct coronary artery implantation has proven to be a reliable and durable procedure for the repair of aortic root and/or ascending aorta aneurysms with concomitant involvement of the aortic valve [1]. The increasing number of elderly patients with complex diseases of the aortic valve and ascending aorta, and the disadvantages of anticoagulation and thromboembolism associated with mechanical valves are stimulating the search for an ideal biological transplant [2, 3]. Homografts, composite conduits with a biological stented or stentless valve prosthesis intraoperatively assembled and stentless xenografts are currently available, each with its advantages and disadvantages [2, 4–7]. In 2007, a new pre-packed biological conduit was introduced into the European market, offering the surgeon a new treatment option for elderly patients with combined disease of the aortic valve and root or for patients in whom anticoagulation should be avoided or is contraindicated.
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2. Materials and methods
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2.1. Patients and surgical indications
This retrospective study has been approved by the local Ethics Committee and signed informed consent was obtained by all patients involved. From April 2007 to January 2008, 21 patients (5 females and 16 males, mean age 67.8±5.5 years) underwent combined replacement of the aortic valve and aortic root with the Bio-ValsalvaTM prosthesis. A bicuspid aortic valve was detected in eight patients. Aortic root aneurysm (17 patients), acute type A dissection (2 patients) and chronic type A aortic dissection (2 patients) were diagnosed by preoperative CT-scan, MRI and/or angiography. Concomitant aortic valve diseases were detected by trans-thoracic echocardiography and consisted of aortic stenosis, steno-insufficiency and severe regurgitation in 7, 6 and 8 patients, respectively. Atrial fibrillation (AF) was detected in three cases while an associated coronary artery disease was found in two patients. The preoperative details of the patients and the procedural data are shown in Table 1.
2.2. Product description
The Bio-ValsalvaTM conduit is a bio-prosthetic heart valved conduit (Fig. 1). The conduit is a combination of CE marked Vascutek Triplex ValsalvaTM vascular graft and CE marked Vascutek ElanTM porcine stentless heart valve (Figs. 1 and 2). The design of the vascular graft mimics the geometry of the sinuses of Valsalva and allows the creation of an anatomical configuration similar to the natural aortic root. The Vascutek Triplex ValsalvaTM graft is manufactured as a triple-layer structure, comprising an inner polyester layer, a central self-sealing elastomeric membrane and an outer layer of ePTFE. This design confers a completely impermeable structure to the graft and it can be stored in glutaraldehyde without changing its characteristics. However, due to the presence of the PTFE layer, the cautery cannot be used to cut the graft.
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Fig. 1. The Bio-ValsalvaTM graft. This biological conduit is a combination of a triplex Valsalva vascular graft and an Elan porcine stentless heart valve.
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Fig. 2. (a, b) The soft sewing ring of the graft is sutured to the annulus with 2-0 pledgeted polyester mattress sutures placed immediately adjacent to each other.
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2.3. Surgical technique
Cardiopulmonary bypass is usually instituted through cannulation of the right atrium and the distal ascending aorta or aortic arch. In patients with aortic arch involvement, a peripheral cannulation (right femoral or axillary artery) is preferred. In these cases, a systemic body temperature of 26 °C is used, and antegrade selective cerebral perfusion is utilized during the period of circulatory arrest. In the remaining cases, the systemic temperature is lowered to 32 °C. Myocardial protection is achieved by antegrade infusion of cold (5–10 °C) crystalloid cardioplegia (Custodiol; Koehler Chemie, Alsbach-Haenlein, Germany). The left ventricle is vented by inserting a cannula through the superior right pulmonary vein. The aortic root is excised leaving only buttons of aortic tissue surrounding each of the coronary arteries, pre-emptively mobilized to prevent tension during reimplantation. The choice of the graft is carried out according to the size of the aortic annulus. The soft sewing ring of the graft is sutured to the annulus with 2-0 pledgeted polyester mattress sutures (Fig. 2a,b). A second suture line with a 4-0 running polypropylene suture is carried out to aid haemostasis. Openings for coronary reimplantation are made with a sharp blade, and not with the cautery, in the appropriate position of the graft skirt (Fig. 3a). A 4–5 mm punch is used to create a circular aortotomy (Fig. 3b,c), taking care to avoid valve leaflets. Coronary ostia are re-attached with a continuous 5-0 polypropylene suture. After the distal anastomosis is performed, the graft is vented with a needle and the heart chambers are de-aired (Fig. 4).
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Fig. 3. (a) Holes for coronary buttons are fashioned with a sharp blade. (b,c) A 4–5 mm punch is used to create a circular hole in the graft skirt.
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3. Results
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3.1. In-hospital outcomes
Surgical procedures were performed under elective conditions in 19 cases and under emergency conditions in 2 cases. Aortic replacement was extended to the hemiarch in 3 cases. Total arch replacement and frozen elephant trunk procedure were performed in two patients affected by chronic type A dissection. CABG and bipolar radiofrequency ablation of the AF were performed as associated procedures in two and three patients, respectively. The cross-clamping time was 119.2±35.7 while the overall cardiopulmonary bypass time was 159.2±72.4 min. The ASCP time was 53.8±30.6 min. In-hospital mortality was 4.7% (one patient died from irreversible arrhythmia). All patients were transferred to the ICU after surgery. The median VAM time was 8 h (range: 5–37 h) while the median ICU stay was 45 h (range: 18–115 h). One patient required a re-thoracotomy due to bleeding. In the same patient, multiple complications occurred, such as acute renal failure requiring multiple dialysis, prolonged mechanical ventilation and septic shock. This patient recovered completely after 83 days of hospital stay. Two patients needed prolonged mechanical ventilation (48 h). Blood transfusions were necessary in another three patients. The mean blood loss from thoracic drains was 206.6±84.5, 321.3±141.9, 530.7±261.3 and 686.4±263.1 ml at 6, 12, 24 and 48 h from ICU admission, respectively. The median in-hospital stay was 12 days (range 7–83). No other complications were observed.
3.2. Hemodynamic characteristics and follow-up
All patients underwent trans-thoracic echocardiography before hospital discharge. In all cases, the valve prostheses were normally functioning. No images of paravalvular leakage or structural degeneration were detected. The mean trans-valvular gradient was 15.2±4.5 mmHg. The mean aortic valve area was 1.9±0.3 cm2 while the mean ejection fraction (EF) was 62.5±9.7%. The median follow-up (FU) was six months and is 100% complete. Clinical examination, ECG and thorax X-rays were performed at 1, 3 or 6 months after discharge, always revealing patients in good general condition.
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4. Discussion
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A variety of pathological conditions involving the ascending aorta and aortic valve often require concomitant ascending aorta and aortic valve replacement. Since the first successful report of the Bentall–De Bono technique [8], the mechanical valved conduit has traditionally been implanted with excellent results. Because of the disadvantages of anticoagulation and thromboembolism associated with mechanical valves [3], there is considerable interest in valve preservation techniques as applied to aortic root aneurysm repair. Unfortunately, valve sparing procedures are not always possible because of leaflet pathology. Moreover, there is an ongoing debate about composite root replacement in elderly patients, namely, whether it should be performed in older patients, especially those with a milder degree of aneurysm formation, or what kind of valve should be used [2]. Composite conduits with a biological stented or stentless valve prosthesis have been used with satisfactory results but they need to be assembled intra-operatively, thus increasing bypass, cross-clamp and procedural time [2]. Stentless xenograft roots offer good outcomes but their length is limited; they are often not long enough to replace the entire ascending aorta, thus requiring a Dacron graft extension resulting in an additional suture line. Furthermore, most patients have annulus diameters large enough to accommodate a stented valve with a low gradient, making a stentless valve less advantageous [5, 7, 9]. Structural degeneration and long-term calcification still constitute an important issue of Shelhigh conduits [6]. Homografts have a remarkable hemodynamic performance, low incidence of thrombo-embolic events and a higher resistance to the infection and re-infection than that of synthetic prostheses. However, cryopreserved homografts can be immunogenic, inducing a strong anti-HLA antibody response similar to chronic rejection, and their use is limited by reduced availability [4]. A pre-sewn biological conduit such as the Bio-ValsalvaTM seems to be a good solution in selected populations of patients and provides a new surgical option for surgeons in the management of elderly patients with aortic root or ascending aorta aneurysm and concomitant aortic valve disease. The use of the ElanTM porcine stentless heart valve seems to be supported by the excellent results obtained by Flynn and colleagues [10]. Our own experience with this valve was very encouraging. We performed more than 60 isolated or combined aortic valve replacements with the Elan valve (not published series) in the last three years without any early death. We observed two late deaths (not cardiac-related) and one case of prosthetic endocarditis. The mean aortic gradient was 12 mmHg at a mean follow-up of 14 months.
The triplex graft has a completely impermeable structure and, even if we did not have any available data, it was a common feeling that the duration of the hemostasis during the procedures was considerably lower when compared to the hemostatic phase after the use of a conventional mechanical conduit.
Moreover, the structure of this new composite conduit leads one to expect, in case of re-operation due to structural valve deterioration, that only the valve cusps and not the entire conduit need to be resected. As for all new technologies, a careful follow-up is mandatory in order to detect any early or late complications.
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5. Conclusions
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In conclusion, the Bio-ValsalvaTM demonstrated ease of implantation. This new graft offers rapid hemostasis due to the trilaminate material of the vascular prosthesis; it has a potential for decreased bypass, cross-clamp and procedural time, and avoids life-long anticoagulation therapies. More patients, longer follow-ups and randomized controlled studies are necessary to validate our early results and to confirm the efficacy of this technique.
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References
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Abstract
1. Introduction