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.     

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.     

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.     

Reoperation due to failure of a Freestyle bioprosthesis

We report re-do aortic valve and ascending aorta replacements by using the valve-on-valve technique for primary tissue failure of a Freestyle bioprosthesis. A 74-year-old male, who had had a 25 mm Freestyle bioprosthetic valve implanted by the sub-coronary method 5 years previously for aortic valve regurgitation due to congenital bicuspid valve, was referred to our hospital for dyspnea and palpitation. He presented with heart failure secondary to aortic regurgitation due to primary tissue failure, and computed tomography demonstrated an enlarged ascending aorta (5 cm in diameter). The operative findings revealed that the Freestyle bioprosthetic valve had a leaflet tear at the left coronary cusp. We replaced the degenerated Freestyle bioprosthesis with a 19 mm Mosaic aortic bioprosthesis by using the valve-on-valve technique, and ascending aorta replacement was performed simultaneously. This technique can be useful for re-do surgery for degenerated stentless valves to avoid potential risks of complete excision of the bioprosthesis.     

Medtronic Freestyle Aortic Root Bioprosthesis: Implant Techniques

BACKGROUND: The Medtronic Freestyle aortic root bioprosthesis is a complete porcine aortic root to allow implantation (1) as a subcoronary valve replacement by removing graft sinus aorta, (2) as a cylinder with the sinotubular junction intact within the aorta (root inclusion), or (3) as a complete aortic root replacement. The choice among the three implant techniques depends on surgeon preference or upon the pathology encountered. The advantages and differences among the three implant techniques are examined. METHODS: The Medtronic Freestyle bioprosthesis was implanted in 1163 patients in a Food and Drug administration (FDA) clinical trial between August 1992 and October 1997. There were 21 centers in the international trial using a single data repository. Clinical data was collected prior to and at operation, at 3 to 6 months and annually. The data were compiled and statistical analysis performed at the data center. RESULTS: Patients having subcoronary valve implants were older (80% > 65 years) and aortic occlusion time was about 20 minutes less than the other methods. Patients having aortic root replacement presented with more aortic valve insufficiency (20%). Pathology of the aortic root and ascending aorta requiring repair was 26%, and larger (27 mm) valves were used in 40% of patients. Risk of operation was lowest (5.0%) with subcoronary valve implants and highest (11.7%) with root replacement technique. Thromboembolism was higher, early and late, with root inclusion (3.0, 3.9%/patient per year) and root replacement (3.2, 3.0%/patient per year) than for subcoronary implants (1.8, 1.6%/patient per year). There were more patients taking warfarin at the 4-year point with root inclusion (20%) or root replacement techniques (24%) than among patients having subcoronary implants (14%). Explants of the valve occurred in 2% of patients, none of whom had aortic root replacement. CONCLUSIONS: The Medtronic Freestyle bioprosthesis is an effective and versatile device for replacement of the aortic valve. It offers implant techniques that can treat the aortic root pathology encountered at surgery and allows the operation to proceed according to surgeon preference.     

Aortic valve/root replacement using a stentless bioprosthesis (Medtronic Freestyle valve)

BACKGROUND: The purpose of the study is to assess the clinical and hemodynamic performance of aortic valve replacement (AVR) with the Freestyle bioprosthesis. METHODS: Twenty-one patients received AVR with a Freestyle aortic root bio-prosthesis between May 1998 and October 1999. Eighteen patients underwent AVR with subcoronary method and three patients with aortic root (full root) method. Patients were evaluated postoperatively at discharge by clinical examination and color Doppler echocardiography. RESULTS: There was one death due to multi-organ failure. No patients experienced valve deterioration, paravalvular leak, unacceptable hemodynamic performance, nor thromboembolic event. Excellent function is demonstrated by very low gradient (mean gradient 7.2 +/- 4.7 mmHg) through aortic valve and no significant aortic regurgitation (none: 11, trivial/mild: 10). All patients had been in New York Heart Association Functional Class III and IV preoperatively, and after surgery, 17 patients were in Class I, and 3 were in Class II. CONCLUSION: The Freestyle bioprosthesis has good clinical and hemodynamic performance without Coumadin. Further follow-up is required to evaluated valve durability.     

Aortic regurgitation due to perforation of the right coronary cusp 10 years after implantation of a freestyle stentless bioprosthesis

Valve deterioration following aortic valve replacement using the Freestyle stentless bioprosthesis is related to cusp tear, operative injury, or infection. We report a patient with aortic regurgitation due to perforation of the right coronary cusp 10 years after implantation of a Freestyle stentless bioprosthesis in the absence of endocarditis.     

Resolution of perivalvular hematoma of the Freestyle stentless aortic root bioprosthesis implanted with a subcoronary technique

The modified subcoronary technique is frequently used to implant the Freestyle aortic root bioprosthesis because of its ease. This technique is primarily associated with hematoma in the potential space between the prosthetic and native aortic walls. We report a case of resolution of perivalvular hematoma around the Freestyle valve 6 months after implantation in a patient with aneurysm of the noncoronary sinus of Valsalva. During follow-up, the patient underwent no significant changes in pressure gradient or degree of regurgitation. Although long-term results are not yet known, the subcoronary technique may be a feasible alternative for patients with aneurysms in the sinus of Valsalva to exclude it, unless the sinotubular junction and aortic annulus are intact.     

Aortic root abscess after percutaneous coronary intervention

A 68-year-old man, who had undergone percutaneous coronary intervention for right coronary disease 2 weeks earlier, was admitted to our hospital for investigation of a fever. Blood culture and echocardiography revealed isolated aortic valve infective endocarditis. He was treated with antibiotics for more than 1 week, but echocardiography showed an aortic root abscess with severe aortic regurgitation. Thus, we performed aortic root replacement using an artificial Freestyle stentless bioprosthesis valve. The patient had an uneventful postoperative course and antibiotic treatment was continued for a further 8 weeks.     

Aortic valve replacement with the freestyle stentless bioprosthesis with respect to spacial orientation of patient coronary ostia

OBJECTIVE: This study evaluates our results for safety and efficacy of aortic valve replacement using the Freestyle bioprosthesis (Medtronic, Inc, Minneapolis, Minn) with a new modified subcoronary implantation technique. This technique takes into account the spacial orientation of the stentless bioprosthesis in the aortic root with respect to the patient's coronary ostia rather than the native commissures. METHODS: Fifty-two consecutive patients with predominant aortic valve stenosis underwent aortic valve replacement with a Freestyle bioprosthesis by means of the described modified subcoronary technique over a 15-month period. Fifty of them were followed up by means of echocardiography at discharge, 6 months, and 1 year. There were 19 men and 31 women, with a mean age of 76 +/- 7 years (range, 58-87 years). Valve size ranged from 21 to 27 mm. RESULTS: Patients with bicuspid aortic valves had a significantly larger angle between both coronary ostia than patients with tricuspid aortic valves (P =.0001). The peak and mean systolic gradients decreased significantly during the first postoperative year for each valve size (P 相似文献   

Aortic root replacement with a freestyle stentless valve for aortitis syndrome with ascending aortic aneurysm and aortic regurgitation.

A 47-year-old woman who had been diagnosed as having aortitis syndrome underwent aortic root replacement for an ascending aortic aneurysm and aortic regurgitation. Because the patient has been treated with steroids for more than 20 years, a Freestyle stentless valve was used to avoid the risk of valve detachment. There were no complications observed during the postoperative course. Although long-term follow-up will be necessary to observe the valve durability, the Freestyle stentless valve seems to be useful for aortic root replacement in patients at high risk of valve detachment due to aortitis syndrome.     

Early experience with the freestyle stentless xenograft

We performed aortic valve replacement with the Freestyle stentless xenograft in 9 patients. There were 6 men and 2 women, whose ages ranged from 44 to 76 years. The modified subcoronary implantation was used in 6 patients and the completely subcoronary implantation was used in 2 patients. The full root replacement was used in 1 patient with bicuspid aortic valve. In a patient who underwent root replacement, postoperative cineangiogram revealed just proximal right coronary artery stenosis. The patient underwent coronary artery bypass grafting to right coronary artery by use of the right internal mammary artery. One in-hospital death occurred on the 46th postoperative day in a patient with severe aortic stenosis and renal failure. 5 patients were investigated by doppler echocardiography at 2 weeks, 3, 6, and 12 months after operation. Peak pressure gradient 1 year after implantation was 11.7 +/- 3.9 mmHg for all valves. No patient had postoperative significant aortic regurgitation.     

Early experience of aortic valve replacement with the Freestyle stentless aortic bioprosthesis in elderly patients.

OBJECTIVES: Stentless bioprostheses have been gaining popularity in recent years as hemodynamically superior alternatives to conventional stented bioprostheses. METHODS: Between July 1996 and November 1998, 13 patients with aortic valve disease, 7 males and 6 females with a mean age (+/- SD) of 68 +/- 5 years, underwent an aortic valve replacement using the Medtronic Freestyle aortic bioprosthesis. The predominant lesions were stenosis in 8 patients and regurgitation in 5, while 2 patients had endocarditis. The operation was performed by a subcoronary technique in 9, root-inclusion technique in 3, and full root technique in 1 patient. RESULTS: Throughout the follow-up periods (with average follow-up period of 20.6 months), there was no hospital mortality, though there was one late death of unknown cause. The New York Heart Association class improved in all patients. The peak transvalvular gradient decreased from 18.4 +/- 9.8 to 12.6 +/- 9.6 mmHg, and the effective valve orifice area increased from 2.30 +/- 0.96 to 2.59 +/- 1.05 cm2 between the 1-month and the 6-month follow-up examinations. In patients with aortic regurgitation, the left ventricular end-diastolic/end-systolic volume index significantly decreased from 147 +/- 36/62 +/- 19 to 73 +/- 26/33 +/- 14 ml/m2 at 1 month after the operation. The left ventricular mass index also significantly decreased from 189 +/- 26 to 143 +/- 30 g/m2 in patients with aortic regurgitation and from 171 +/- 28 to 144 +/- 30 g/m2 in those with aortic stenosis. CONCLUSIONS: Although long-term follow-up is required for further evaluation, the early results appeared to indicate that the Freestyle aortic bioprosthesis was suitable for elderly patients requiring aortic valve replacement.     

Late disruption of a Freestyle stentless bioprosthesis used for repair of sinus of Valsalva aneurysm of noncoronary cusp

We present a case of disruption of the porcine aortic wall of the 27-mm Freestyle stentless bioprosthesis 5 years after the subcoronary implantation to exclude the sinus of Valsalva aneurysm of the noncoronary cusp. At the urgent reoperation, the inflow suture line was found to be intact, and therefore a new stented valve was sutured with the inflow Dacron cuff after removal of ruptured valve. The subcoronary implantation technique creates a cavity between the prosthetic and native aortic walls filled with hematoma. The outflow suture line dehiscence caused blood flow into the cavity, porcine aortic wall rupture, and leaflet destruction.     

The extended Biocor stentless aortic bioprosthesis. Early clinical experience.

In the "Extended" Biocor stentless aortic bioprosthesis, supra- and subvalvular extensions to a bovine pericardium ring carry three porcine leaflets. The extensions cover the "non-coronary" sinus of the prosthesis and allow optional enlargement of the aortic root down towards the mitral valve as well as upwards into the aortotomy. Seventy-one patients with this stentless valve (62 with predominantly aortic stenosis, 28 with concomitant CABG) are being prospectively studied. This paper reports follow-up one year after insertion. The upper and lower pericardial extensions were used in 61 and 11 patients, respectively. The average prosthetic valve size was 23.2 +/- 1.6 mm. Early mortality was 7% (5/71); late mortality (4/66, 5%/patient year) was not valve-related. Symptoms of thromboembolism (new neurological defects) occurred in four patients. There was no valve failure or late endocarditis. One year postoperatively the transvalvular mean pressure difference for all valves was 7.9 (3.1-18.4) mmHg. None of the patients had haemodynamically significant aortic regurgitation at follow-up; nine had trivial regurgitation. The "Extended" Biocor stentless bioprosthesis thus has a favourable haemodynamic profile and can be advantageous in elderly patients with narrow aortic roots, and often with thin and/or calcified aortic walls.     

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.     

Perforation of the Valsalva sinus after implantation of Medtronic Freestyle aortic bioprosthesis

We report on structural valve deterioration in patients with the Medtronic Freestyle aortic bioprosthesis (Medtronic, Inc, Minneapolis, MN), including spontaneous perforation of the Valsalva sinus. These occurred in four prosthesis in 3 patients using the modified subcoronary method or full root technique. One patient died of ruptured pseudoaneurysm and the others survived reoperation well. Careful follow-up is required after Freestyle bioprosthesis implantation.     

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.     

Aortic valve replacement with a stentless porcine aortic root bioprosthesis

From April, 1999 to November, 1999, 8 patients underwent the aortic valve replacement using Medtronic Freestyle aortic root bioprosthesis. Mean age was 67.8 years old. Aortic valve etiology was as follows, AS: 1 case, AR: 2 cases, ASR: 3 cases, IE: 1 case, mechanical valve malfunction due to subvalvular pannus: 1 case. The implanted valve size was 25: 2 cases, 23: 3 cases, 21: 1 cases, 19: 2 cases. Surgical technique was subcoronary: 7 cases, full-root: 1 case. Post-op 2D-echo revealed tribial aortic valve incompetence in two cases because of size discrepancy between the aortic annulus and the ascending aorta. Pacemaker implantation was needed in 1 case because of the complete A-V block. In comparison with 5 cases of aortic valve replacement with Hancock II performed in same period, there were no significant differences about the implanted valve size and mean systolic pressure gradient, but the effective orifice area in Freestyle cases was significantly larger than Hancock II cases.     

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.