Aortic Valve Replacement with Stentless Porcine Bioprostheses

The implantation of stentless porcine valves (SPVs) is technically more demanding than implantation of stented bioprosthetic valves. Implantation of the Toronto SPV bioprosthesis requires an,understanding of the relationships between the leaflets and the aortic annulus and sinotubular junction. In addition to proper alignment of the three commissures within the aortic root, the diameter of sinotubular junction should not exceed the external diameter of the porcine aortic valve after completion of the operation. The Medtronic Freestyle porcine aortic root bioprosthesis can be used for subcoronary implantation as well as for aortic root replacement. Degenerative calcification of a tricuspid aortic valve is the most common cause of aortic valve disease in older patients. Implantation of stentless valves in the subcoronary position is usually feasible because the geometry of the aortic root is well maintained in these patients. The bicuspid aortic valve is the second most common cause of aortic valve disease in older patients and the most common in younger patients. These patients frequently have dilated aortic root, and the Medtronic Freestyle bioprosthesis is ideal for implantation using the root inclusion technique. Stentless porcine bioprostheses are minimally obstructive and associated with low mean systolic gradients. In addition, they have better hemodynamic performance during exercise than stented bioprostheses. For these reasons, patient-prosthesis mismatch has not been described with stentless valves. Left ventricular function after aortic valve replacement appears to be better with stentless than with stented bioprostheses. Comparative, nonrandomized studies of aortic valve replacement with stented and stentless valves suggest that the risk of cardiac death is reduced with stentless valves and the rates of valve-related complications also appear to be lower. What remains unknown is whether stentless valves are more durable than stented ones.     

Redo aortic root replacement for prosthetic valve detachment associated with recurrent aneurysm of sinus of valsalva due to aortitis syndrome

We report a case of 44-year-old male with aortitis syndrome who suffered a prosthetic aortic valve detachment and recurrent aneurysm of sinus of Valsalva 5 years after aortic valve replacement and patch closure of non-coronary sinus of Valsalva. Preoperative computed tomography (CT) and angiography revealed severe aortic regurgitation and complicated aneurysm formation of sinus of Valsalva due to prosthetic valve and prosthetic patch dehiscence. Aortic root replacement was performed successfully after induction of steroid therapy to control inflammation. His postoperative course has been uneventful for 18 months.     

Composite stentless valve with graft extension for combined replacement of the aortic valve, root and ascending aorta.

OBJECTIVE: The composite mechanical valve conduit has been most commonly used for patients who require combined aortic valve, root, and ascending aorta replacement, but is limited, especially in the elderly, because of the need for long-term anticoagulation. We report the first consecutive series of patients in whom a composite stentless valve with graft extension, which does not require long-term anticoagulation, was performed. METHODS: Between April 1998 and July 2000, eight patients with severe aortic root and ascending aortic pathology underwent a combined aortic valve, root, and ascending aorta replacement with a Freestyle stentless porcine valve with a Hemashield graft extension. Mean age was 74 (range 56--82), three were males. Concomitant procedures included coronary artery bypass graft (CABG) alone (n=2), mitral valve replacement with atrial septal defect repair (n=1) and CABG with septal myomectomy (n=1). RESULTS: Operative mortality was zero. Median aortic cross-clamp and cardiopulmonary bypass times were 150 and 203 min, respectively. Two patients returned to the operating room for bleeding. Median blood transfusions and hospital length of stay were 4 units and 11 days, respectively. CONCLUSIONS: The composite stentless valve with graft extension is a reasonable alternative to a mechanical valve conduit for patients who require a combined aortic valve, root, and ascending aorta replacement, in whom anticoagulation is not desirable or contraindicated.     

A technique of aortic annulus enlargement with a Freestyle stentless bioprosthesis

We describe our surgical technique to manage a small aortic annulus during aortic valve replacement. Starting with the posterior annular enlargement incision described by Manouguian, a stentless porcine aortic root, with excision of the left and right porcine coronary segments and conservation of the mural wall (Freestyle MS design, Medtronic, Minneapolis, MN ), was used. The Freestyle bioprosthesis enlarges the aortic annulus using a direct suture of the valve on the enlarged annulus, and the aorta is closed by a direct suture of the mural wall of the bioprosthesis. Therefore, the aortic annulus enlargement is made only using the aortic bioprosthesis, without other material.     

Aortic valve replacement with a freestyle stentless valve using the modified subcoronary technique and hemiarch replacement for bicuspid aortic valve and ascending aortic aneurysma; report of a case

An association between bicuspid aortic valve disease and ascending aortic aneurysma has long been recognized. Root replacement with a composite valve graft for such disease is a well-established technique. But it may involve serious technical difficulties, and may be a more time-consuming procedure than separate valve replacement and graft replacement. We performed an aortic valve replacement with Freestyle stentless valve using the modified subcoronary technique and hemiarch replacement for a 72-year-old man with severe aortic stenosis and ascending aortic aneurysma. Angiographic studies after surgery showed no residual aortic regurgitation (AR) and no deformity of aorta. This technique is an acceptable option for an aortic disease and ascending aneurysma in elderly patients.     

The freestyle stentless aortic bioprosthesis: more about the subcoronary technique.

Two years after aortic valve replacement with a Freestyle stentless aortic xenograft using the partial scallop inclusion technique, late prosthetic valve endocarditis developed with abscess formation in the space between the porcine and native human aortic wall. The presence of such a periprosthetic dead space exposes the patient to increased postoperative pressure gradients and the risk of superinfection.     

Surgical treatment in a patient with multiple systemic complications of prosthetic aortic valve endocarditis: case report

A 31-year-old woman who had undergone aortic and mitral valve replacement 1 year previously was hospitalized with suspected prosthetic valve endocarditis. Freestyle stentless aortic xenograft was successfully replaced using freestanding total aortic root replacement techniques at the left ventricular outflow tract position, and aorta-to-right coronary artery bypass was also applied with a saphenous vein graft. The patient developed multiple systemic problems during the preoperative and postoperative periods and was successfully treated with intensive interventions. She was discharged at the postoperative fourth month, and the following 28 months were uneventful.     

Efficacy of aortic valve replacement with freestyle stentless valve in patients with aortic valve disease

Stentless porcine aortic bioprosthesis has several potential advantages over conventional stented bioprosthesis. The Medtronic Freestyle aortic bioprosthesis, a stentless design analogous to an aortic allograft, has zero-pressure-fixed leaflets treated with an antimineralization agent, and has been shown to have benefits of superior effective orifice area, excellent flow characteristics and durability. To evaluate the early results for its efficacy in view of post-operative performance. The valve was implanted using the cylinder method, with subcoronary, root-inclusion techniques or full root techniques. No patients experienced any significant valvular regurgitation on echocardiography. The post-operative data of EDVI, ESVI and LVPWD decreased significantly as compared with the pre-operative data while ejection fraction remained unchanged. The average peak pressure gradient was 16.5 mmHg, and the average effective orifice area was 2.45 cm2. In conclusion, Freestyle stentless aortic bioprosthesis showed excellent hemodynamic function. It seems to be suited for the older patient with a small aortic annulus.     

Acquired von Willebrand disease type IIA in patients with aortic valve stenosis

The authors report the case of a 72-year-old woman with severe aortic stenosis who had a bleeding tendency develop due to type IIA acquired von Willebrand disease. She underwent aortic valve replacement with a 19-mm Freestyle stentless valve (Medtronic Inc, Minneapolis, MN). The postoperative course was uneventful and the bleeding tendency resolved. A review of this operative case from our institution demonstrated that aortic valve replacement was one of the most effective treatments of this disease, which can be potentially lifesaving.     

Eight-year results after aortic valve replacement with the Freestyle stentless bioprosthesis

OBJECTIVES: We sought to describe the hemodynamic and clinical outcomes for the Freestyle aortic root bioprosthesis (Medtronic, Inc, Minneapolis, Minn) in a large multicenter cohort prospectively followed for 8 years. METHODS: A total of 700 patients (651 [93%] >60 years of age) at 8 centers in North America were followed prospectively after aortic valve replacement with the Freestyle stentless bioprosthesis; the implant technique was subcoronary in 500, total root in 162, and root inclusion in 38. Follow-up was 3395 patient-years (4.9 +/- 2.3 years per patient). Clinical and echocardiographic follow-up was prospectively obtained at yearly intervals. RESULTS: For the subcoronary, total root, and root inclusion groups, actuarial freedom from valve-related death was 96.8% (SE 3.0%), 92.3% (SE 7.7%), and 90.9% (SE 11.2%), respectively, and freedom from structural deterioration was 98.6% (SE 2.0%), 100.0% (SE 0.0%), and 100.0% (SE 0.0%), respectively. Hemodynamics remained excellent at 6 years. Freedom from moderate or more aortic regurgitation was 86.0% (SE 5.1%), 98.7% (SE 3.9%), and 97.3% (SE 6.6%), respectively. Gradients were slightly lower (P =.0009), and the effective orifice area (P =.02) and freedom from aortic regurgitation were slightly higher (P =.03) with total root than subcoronary implantation. CONCLUSIONS: The Freestyle stentless aortic root bioprosthesis is a versatile option for aortic valve replacement. Measures of clinical outcomes and prosthesis durability remain excellent in multicenter follow-up through 8 years in a population predominantly older than 60 years at the time of the operation.     

Aortic valve replacement with stentless porcine aortic bioprosthesis

Twenty-nine patients were entered in a clinical trial on aortic valve replacement with a stentless glutaraldehyde-fixed porcine aortic valve. This bioprosthesis is secured to the aortic root by the same technique used for aortic valve replacement with aortic valve homografts. The functional results obtained from this operation have been most satisfactory. To assess the hemodynamic benefit of eliminating the stent of a porcine aortic valve, we matched 22 patients with a stentless porcine bioprosthesis for age, sex, body surface area, valve lesion, and bioprosthesis size to 22 patients who had aortic valve replacement with a Hancock II bioprosthesis. Mean and peak systolic gradients across the aortic bioprosthesis and effective aortic valve areas were obtained by Doppler studies. Gradients across the stentless bioprosthesis were significantly lower than gradients across the Hancock II valve for every bioprosthesis size. Effective aortic valve areas of the stentless bioprosthesis were significantly larger than the valve areas of the Hancock II valve. Our data demonstrate that the hemodynamic characteristics of a glutaraldehyde-fixed porcine aortic bioprosthesis are greatly improved when the aortic root is used as a stent for the valve. This technique of implantation is expected to enhance the durability of the bioprosthesis, because the aortic root may dampen the mechanical stress to which the leaflets are subjected during the cardiac cycle.     

Stentless full root bioprosthesis in surgery for complex aortic valve-ascending aortic disease: a single center experience of over 300 patients.

OBJECTIVE: The technically demanding full root aortic valve replacement necessitating coronary ostia reimplantation apparently leads to hesitation by some surgeons despite the superior hemodynamics and excellent long-term clinical performances of the stentless xenografts. Clinical data of stentless full root replacements was retrospectively analyzed in this perspective for validation. METHODS: From November 1999 to March 2007, 317 adult patients (male: 196, female, 121) underwent modified Bio-Bentall procedure using the Medtronic Freestyle xenograft as a full root replacement. Two hundred and three patients received an isolated root replacement or a root and ascending aortic replacement (ARR). In 114 patients a variety of concomitant procedures including coronary artery bypass grafting (n=32), mitral valve repair (n=11) and aortic arch replacement (n=36) were performed. (ARR+). RESULTS: Mean patient age was 70.3+/-10.2 years (range 17-94 years), 97 patients were 75 and older at time of procedure. Mean operative time for the ARR was 190+/-57 min with a clamp time of 88+/-27 min. Mean operative time for ARR+ group was 282+/-93 min with an average clamp time of 110+/-32 min. Overall operative mortality was 7.9% (25/317), for ARR it was 5.4% (11/203). Mean ICU stay was 4.9+/-8.1 days, mean hospital stay being 9.8+/-8.1 days. Necessity for bailout bypass surgery among patients with ARR was low at 1.5% (3/203) comparable to stented xenograft implantations. Echocardiography demonstrated excellent clinical results with low transvalvular gradients especially when a single suture inflow anastomosis technique was used. CONCLUSIONS: Full root stentless valve implantation preserving porcine root integrity is a valuable option in aortic valve/ascending aorta surgery. Though technically a more challenging operation, it does not lead to increased perioperative morbidity and mortality and can be beneficial mainly for elderly patients with small aortic roots with or without aortic root pathology.     

Replacement of the aortic root and ascending aorta using a freestyle valve and woven Dacron graft

We contrived a surgical technique for the purpose of improving recent results. From April 1998 to June 2001, 24 patients (aged 60 to 81 years, mean age 71.0 +/- 4.8 years; 11 men, 13 women) underwent replacement of the aortic root and the ascending aorta electively using a Freestyle stentless valve with woven Dacron graft at our institution. The aortic root was replaced first, the distal side of the Dacron graft was then anastomosed, and finally, the proximal side was anastomosed with the outflow of the Freestyle valve. Cardiopulmonary bypass time and cardioplegic time were 297 +/- 83 min and 210 +/- 51 min, respectively. The geometry of the ascending aorta and the diameter mismatch between the dilated ascending aorta and the outflow of the Freestyle valve were fully corrected. There were two early deaths and three late deaths; none valve-related. Postoperative aortogram showed an excellent shape. The mortality, morbidity, and clinical events after the procedure were acceptable.     

Eight-year results of aortic root replacement with the freestyle stentless porcine aortic root bioprosthesis

Background. Stentless porcine aortic valves offer several advantages over traditional valves. Among these are superior hemodynamics, laminar flow patterns, lack of need for anticoagulation, and perhaps improved durability.

Methods. One hundred four patients were operated on from September 17, 1992, to October 31, 1997, as part of a multicenter worldwide investigation of the Medtronic Freestyle stentless porcine bioprosthesis. All patients received a total aortic root replacement. The patients were evaluated postoperatively at discharge, at 3 to 6 months, and yearly by clinical examination and color flow Doppler echocardiography.

Results. Operative mortality was 3.9%. No patient experienced structural valve deterioration, nonstructural deterioration, perivalvular leak, or unacceptable hemodynamic performance. At 8 years, survival was 59.8%. Freedom from thromboembolic complications was 83.3%. Freedom from postoperative endocarditis was 96.9%. Freedom from reoperation was 100%. Mean systolic gradients did not change over the time period studied. They were 6.4 ± 3.8 mm Hg at 1 year and 6.7 ± 2.6 mm Hg at 8 years. Correspondingly, effective orifice area was 1.9 ± 0.7 cm² at 1 year and 1.8 ± 0.8 cm² at 8 years. The incidence of any aortic insufficiency also did not change over the length of follow-up. At 1 year, 98% of patients had no or trivial aortic insufficiency and 2% had mild aortic insufficiency. At 8 years, 100% of patients evaluated were free of any aortic insufficiency.

Conclusions. The Medtronic Freestyle aortic root bioprosthesis can be used safely to replace the aortic root or aortic valve for aortic valve and aortic root pathology. Total root replacement allows optimal hemodynamic performance with no significant aortic regurgitation. Results up to 8 years show excellent survival and no signs of degeneration. Further follow-up is still needed to determine valve durability.     

Prosthetic valve endocarditis with extensive aortic root abscess

Prosthetic valve endocarditis with an extensive aortic root abscess usually has high mortality and morbidity. A 71-year-old male with an extended aortic root abscess following aortic valve replacement survived after full aortic root reconstruction with glutaraldehyde bovine pericardium, mitral valve replacement and full root replacement using stentless bioprosthesis. The patient is well without recurrence of infection, 18 months postoperatively. This procedure might be an alternative treatment for prosthetic valve endocarditis with an extended aortic root abscess.     

Surgical treatment for aortic regurgitation caused by non-specific aortitis.

Aortic regurgitation caused by non-specific aortitis is relatively rare, and prosthetic valve detachment after aortic valve replacement has been reported to be one of the most serious complications. The authors investigated the surgical results in patients with aortic regurgitation caused by non-specific aortitis. Between 1978 and 1997, 90 patients with aortic regurgitation secondary to non-specific aortitis underwent surgery. There were 28 males and 62 females. The age of these patients ranged from 19 years to 70 years (mean, 48 years). Sixty-five patients were diagnosed to have Takayasu's arteritis, 10 had Beh?et's disease and 15 had aortitis of unknown etiology. The surgical procedures for aortic regurgitation were aortic valve replacement in 62 patients, Bentall-type operation in 27 and remodeling in one. Five patients (5.6%) died during the hospital stay. The follow-up duration ranged from 1 month to 224 months (mean, 98 months). Twenty-one patients died during the follow-up period, and the actuarial survival rate was 83% at 5 years and 68% at 10 years. Prosthetic valve detachment occurred in 12 patients (13.3%). Two patients required a re-aortic valve replacement, eight had a composite graft replacement and two patients underwent a homograft reconstruction. Absence of prosthetic valve detachment was noted in 83% of the patients at 5 years and in 75% at 10 years. The incidence of prosthetic valve detachment was 40% (4/10) in patients with Beh?et's disease, 33% (5/15) in aortitis of unknown etiology, 4.6% (3/65) in Takayasu's arteritis and 29% (8/28) in male patients. Surgical techniques for treatment of this condition should be modified for further improvement of the surgical outcome in these patients with Beh?et's disease and aortitis of unknown etiology.     

Surgical treatment with the freestyle bioprosthesis and omentopexy for prosthetic valve endocarditis after aortic root replacement

A 60-year-old woman, who had undergone aortic root replacement with composite graft 5 months previously, suffered from anemia and slight fever. Transthoracic echocardiography showed pseudoaneurysm in the aortic root, and blood culture was positive. She was diagnosed with prosthetic valve endocarditis, and surgical intervention was planned. Intraoperatively necrotic tissue and dehiscence of the suture line in the aortic annulus were found. Re-aortic root replacement with Freestyle bioprosthesis and re-hemiarch graft replacement were performed with the omentopexy around the aortic root and the new graft. Antibiotics were administered intravenously for 6 weeks postoperatively. At 7 months after the operation, no prosthetic valve infection had recurred. Although the long-term results of Freestyle bioprosthesis have not been determined, it might be a valuable option for aortic root infection as an alternative to an aortic homograft. In addition, omentopexy might also be effective in the prevention of recurrent prosthetic valve infection.     

The Freestyle stentless bioprosthesis for prosthetic valve endocarditis

We report a case of methicillin-resistant Staphylococcus aureus-induced prosthetic valve endocarditis, which was successfully treated with aortic valve replacement using the Freestyle stentless bioprosthesis. The total root and stentless design of this bioprosthesis allows for more radical removal of infected tissue and easier treatment for annular abscess, while requiring less prosthetic materials than a conventional prosthesis. This bioprosthesis thus seems to be a valuable option for active endocarditis.     

Impact of implant technique following freestyle stentless aortic valve replacement

BACKGROUND: Stentless aortic bioprostheses have excellent hemodynamics and clinical outcomes. The purpose of the present study was to determine whether implant technique of the Freestyle aortic root bioprosthesis impacts clinical outcomes or hemodynamic performance. METHODS: The long-term multicenter study of the Freestyle stentless aortic bioprosthesis includes 500 consecutive patients implanted using the subcoronary and 162 using the full root technique. Clinical outcomes and echocardiographic hemodynamics were compared through 5 years. RESULTS: There were no differences between groups in time to death, valve-related death, or reoperation. The incidence of operative death was higher in the full root than in the subcoronary group (odds ratio 3.97, p = 0.001). Patients in the subcoronary group were more likely to have New York Heart Association functional class III or IV symptoms at 1 year (1.7% versus 0%, p = 0.04) and 5 years postoperatively (4.4% versus 0%, p = 0.02). Mean gradient was lower (p = 0.0004) and effective orifice area larger (p = 0.04) in the full root group. Left ventricular mass index decreased in both groups. The preponderance of patients in both groups had no or trivial aortic regurgitation through 5 years. CONCLUSIONS: Full root implantation of the Freestyle stentless aortic bioprosthesis was associated with higher operative mortality, but somewhat better hemodynamics, functional class, and freedom from aortic regurgitation. Higher operative mortality argues against the empiric replacement of the ascending aorta in the absence of aortic root pathology. In appropriately selected patients, both implant techniques are viable alternatives for valve implantation.     

大动脉炎导致主动脉瓣关闭不全的外科治疗

目的　探讨大动脉炎导致主动脉瓣关闭不全的外科治疗方法。方法　 1990年 12月至2 0 0 2年 7月 ,手术治疗大动脉炎致主动脉瓣关闭不全 2 0例 ,12例行主动脉瓣机械瓣置换术 (AVR) ;8例行主动脉根部置换术 (ARR) ,包括Bentall术 5例 ,Carbrol术 2例 ,David术 1例。结果　全组无手术死亡。平均随访 ( 2 4 14± 2 1 12 )个月 ,最长 6 1个月。术后发生瓣周漏或瓣撕脱 7例 ,全部为AVR术后。再次手术 7例 ,其中 3例因再次瓣周漏第 3次手术 ;死亡 4例 ,远期死亡率为 2 0 %。结论　恰当的手术时机、适宜的手术方法和长期抗炎治疗有助于提高大动脉炎导致主动脉瓣关闭不全病人的外科疗效。