Stentless aortic valve replacement with Freestyle or Toronto SPV: an early comparison

St. Jude Medical Toronto biologic aortic root prosthesis: Early FDA phase II IDE study results

BACKGROUND

Several biological aortic root replacement techniques have distinct advantages over mechanical composite root replacement including better valvular hemodynamic characteristics and the lack of need for anticoagulation. Current biological root replacement options lack proven long-term durability or are limited by technical or practical concerns. We report the early results from a phase II multicenter clinical trial of the porcine St. Jude Toronto Bioprosthesis with BiLinx (Toronto root).

METHODS

176 Toronto roots were implanted as total aortic root replacement from August 2001 through August 2003. Concomitant cardiac procedures including coronary artery bypass grafting (31%) and ascending aortic replacement (55%) were performed in 74%. Patients were followed clinically and were examined with an echocardiogram at discharge, 6 months, 12 months, and yearly thereafter. Root sizes implanted included 29 mm in 38%, 27 mm in 30%, 25 mm in 20%, 23 mm in 10%, and 21 mm in 2.2%.

RESULTS

There are 205 patient years of follow-up through October 2003. Operative mortality was 3.9% (none were valve related) and late mortality was 4%. Operative stroke rate was 1.1% and late stroke rate was 0.6%. Endocarditis developed in 1 patient. Freedom from aortic regurgitation is to date 100% at discharge, 6 months, and 1 year postimplant. Reoperation of the aortic valve/root was not required in any patient. Six-month mean transvalvular gradients for 21-29 mm valves were 12.8, 8.8, 5.3, 4.9, and 4.7 mm Hg, respectively.

CONCLUSIONS

Aortic root replacement with the Toronto root is safe and provides superb transvalvular hemodynamics with freedom from anticoagulation. The Toronto root seems widely applicable for all types of aortic root pathology and these early data offer very encouraging results. Long-term follow-up is required.

Results with the freestyle porcine aortic root for right ventricular outflow tract reconstruction in children

BACKGROUND

The ideal choice for valved reconstruction of the right ventricular outflow tract (RVOT) in children is undetermined. This study explores the Freestyle porcine aortic root for these patients.

METHODS

From January 1998 to December 2002, 56 patients ages 1.6 to 29.9 years old (mean 11.8 years old) underwent RVOT reconstruction using a Freestyle porcine aortic root. The patients averaged 1.9 prior operations (range 0 to 5) for tetralogy of Fallot +/- pulmonary atresia (28 patients), critical pulmonary stenosis (10 patients), Ross procedure (5 patients), pulmonary atresia/intact ventricular septum (4 patients), complete atrioventricular septal defect +/- tetralogy of Fallot (4 patients), and others (5 patients). At time of RVOT reconstruction, 42 patients (75%) had additional procedures including the following: tricuspid or mitral repair (24 patients), pulmonary arterioplasty +/- Glenn (12 patients), ventricular septal defect closure (5 patients), aortic valve replacement (3 patients), placement of a cardioverter/defibrillator or pacemaker (3 patients), and others (8 patients).

RESULTS

One patient developed mediastinitis; another was treated for Candida endocarditis (his excised homograft unexpectedly grew Candida). All patients are well on follow-up from 2 to 60 months (mean 30 +/- 20 months) with no deaths. The patient with endocarditis underwent conduit replacement for recurrent pulmonary stenosis 3.5 years postoperatively. Echocardiography revealed mild or no pulmonary insufficiency in 93%. The calculated mean peak systolic RVOT gradient by echocardiography was 19.7 +/- 15.4 mm Hg.

CONCLUSIONS

These data demonstrate excellent results with the Freestyle bioprosthesis for RVOT reconstruction in children. This valve may serve as a readily available alternative to homograft valves in RVOT reconstruction, particularly since early insufficiency seems to be less problematic. Questions of long-term durability and significance of echocardiographic stenosis remain unanswered.

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.