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.     

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.     

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   

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.     

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.     

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.     

Aortic valve replacement with medtronic freestyle bioprosthesis: operative technique and results

OBJECTIVE: This study evaluates the initial results for safety and efficacy of aortic valve replacement (AVR) using the Medtronic Freestyle Bioprosthesis. METHODS: One hundred three patients underwent AVR with the Medtronic Freestyle Bioprosthesis over a 40-month period. There were 59 male and 44 female patients with a mean age of 74 years (range 36 to 88 years). Valve size ranged from 19 to 27 mm, and all valves were implanted using a freehand subcoronary technique. Anticoagulation with coumadin was only used for atrial fibrillation. Aspirin was given to patients with associated coronary artery disease. Echocardiography to assess transvalvular pressure gradient and effective valve orifice area was performed at discharge, 3 to 6 months, 1 year, and then annually. RESULTS: There were 4 (3.9%) deaths within 30 days of operation and 5 (4.9%) late deaths. Two (1.9%) deaths were valve-related, one from commissural dehiscence and one from bacterial endocarditis. Three (2.9%) deaths, two early and one late, were from other cardiac causes. The remaining deaths were from noncardiac causes. Five (4.9%) patients suffered a thromboembolic event, two had permanent neurological deficits, two had transient neurological events, and one had coronary artery occlusion. Mean transvalvular gradient assessed by echocardiography was low at all time intervals: discharge (12.8 mmHg), 3 to 6 months (11.3 mmHg), 1 year (12.0 mmHg), and 2 years (11.6 mmHg). Mean effective valve orifice area was good at all time intervals: discharge (1.4 cm2), 3 to 6 months (1.5 cm2), 1 year (1.6 cm2), and 2 years (1.6 cm2). Of the 38 patients assessed by echocardiography at 1 year, 33 (87%) had no or trivial valve incompetence and the remainder had mild valve incompetence. CONCLUSIONS: Aortic valve replacement with the Medtronic Freestyle Bioprosthesis has a low incidence of early valve-related mortality and thromboembolism. The bioprosthesis demonstrates good hemodynamic performance even in small diameters and is particularly well suited for older patients and the small aortic root.     

Stentless Xenograft Repair of Excavating Aortic Root Sepsis

BACKGROUND: A variety of surgical techniques are used to manage a disintegrated aortic annulus in patients with endocarditis and excavating aortic root sepsis. Homograft root replacement is preferable in this setting but suitable homografts are restricted in availability and excision of the aortic root carries the risk of postoperative bleeding. As an alternative we used a stentless porcine xenograft root (Medtronic Freestyle valve) to manage this problem. METHODS: Three male patients with active endocarditis presented with aortic root abscess and partial or complete aorto-left ventricular discontinuity. One had prosthetic valve endocarditis, and the abscess cavity entered the right atrium in another. The porcine aortic root was successfully implanted using the modified subcoronary technique providing a repair within the aortic root with proximal and distal suture lines that excluded the disintegrating tissues from the blood stream. All patients were treated with intravenous antibiotics for 6 weeks postoperatively and none suffered recurrent infection (follow-up > 6 months). CONCLUSION: The stentless porcine aortic root implanted within the human aorta provides an additional surgical option for excavating aortic root sepsis.     

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.     

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.     

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.     

The first experience with using xenografts in treatment of aortic valve disease

A comparative analysis of biomechanics of implanted xenografts has shown that the functioning of the newly formed aorta root might be dependent on constructive features of the bioprosthesis, choice of the optimal type size and on the implantation technique. The best hemodynamic and biomechanical characteristics were obtained when using the technique of a complete prosthesis of the aorta root with the Medtronic Freestyle xenograft and subcoronary implantation of bioprosthesis AB-Mono- and AB-Composit-Kemerovo.     

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.     

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.     

应用无支架Medtronic生物瓣行主动脉瓣替换

评估无支架Ｍｅｄｔｒｏｎｉｃ生物瓣作主动脉瓣替换的安全性和临床效果。方法以冠状动脉开口下方植入技术用无支架Ｍｅｄｔｒｏｎｉｃ生物瓣作主动脉瓣替换共８５例。易除左、右冠状动脉空运保留完整的无冠窦,全部采用连续缝合方法。结论无支架Ｍｅｄｔｒｏｎｉｃ生物瓣作主动脉瓣替换效果良好,适用于年龄超过７５岁以及伴有狭小动脉根部的病人。     

When a Mechanical Valve Goes Freestyle: A Patient Tailored Valve-In-Valve Implantation

In case of a redo operation after a full root replacement there are two possible options: replacing the entire root or performing a more conservative valve-in-valve implantation. Regarding the relatively high morbidity and mortality of a redo root replacement, the valve-in-valve implantation is the preferred choice if technically feasible. We present the case of a valve-in-valve implantation with a St. Jude mechanical valve in a Medtronic bioprosthesis in a 57-year old man. Follow-up echocardiography after 1 month showed a mean gradient of 17 mmHg and no paravalvular leakage. The combination of a St. Jude bileaflet mechanical valve implanted in a Freestyle root prosthesis has not been described. This case shows that patient tailored treatment with a St. Jude bileaflet mechanical valve in a Freestyle aortic root valve can be safely performed and might be the preferred choice for younger patients, if technically feasible.     

Successful implantation of self-expanding valve for a failed stentless prosthesis

Valve-in-valve transcatheter aortic valve implantation is currently used for failed bioprosthesis. The use of a transcatheter prosthesis in a regurgitant noncalcified root implanted Medtronic Freestyle prosthesis is particularly challenging. We present a successful transaxillary valve-in-valve implantation of a self-expandable transcatheter aortic valve prosthesis in a failed Freestyle bioprothesis implanted eleven years earlier. Tips and tricks are discussed.     

Long-term survival after xenograft versus homograft aortic root replacement: Results from a prospective randomized trial

ObjectiveThe study objective was to investigate the long-term survival of patients undergoing xenograft versus homograft full root aortic valve replacement.MethodsA total of 166 patients requiring aortic valve surgery were randomized to undergo the Freestyle (Medtronic Inc, Minneapolis, Minn) bioprosthesis (N = 90) or a homograft (N = 76) full root aortic valve replacement between 1997 and 2005 in a single institution. Six patients randomly assigned to the homograft crossed over to the Freestyle bioprosthesis because of the unavailability of suitably sized homografts. All surgeons were required to adhere to the standard surgical technique for homograft root implantation previously described. Follow-up was 98.5% complete.ResultsThe mean age of the study population was 65 ± 8 years. Coronary artery bypass grafting was associated with root aortic valve replacement in 76 of 166 patients (46%, P = not significant between groups), and overall hospital mortality was 4.8% (8/166, P = not significant between groups). Median follow-up was 13.8 years (range, 0-21.8 years; 2033 patient-years). The Kaplan–Meier survival analysis showed that there was no significant difference in overall survival between the 2 arms at 5, 10, and 15 years. Twenty-year survival was 28.3% ± 5% for the Freestyle group versus 25.1% ± 5.7% for the homograft group (P = .90), which was comparable to the age- and sex-matched UK general population. The freedom from aortic valve reoperation at 20 years was comparable for the Freestyle group versus the homograft group (67.9% ± 8.8% vs 67.2% ± 10.3%, respectively; P = .74).ConclusionsThis is the first study to investigate the long-term survival of xenograft versus homograft full root aortic valve replacement from a prospective randomized trial. The observed 20-year overall survival and freedom from aortic valve reoperation serve as a benchmark for future studies on interventions for aortic valve disease in the elderly.