Original Articles
Aortic root replacement with the freestyle stentless porcine aortic root bioprosthesis

Presented at the Forty-fifth Annual Meeting of the Southern Thoracic Surgical Association, Orlando, FL, November 12–14, 1998.
https://doi.org/10.1016/S0003-4975(99)00370-7Get rights and content

Abstract

Background. Stentless porcine prosthetic 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 and twelve patients were operated on from September 17, 1992 to April 13, 1998 as part of a multi-center worldwide investigation. All patients received a total aortic root replacement. Patients were evaluated postoperatively at discharge, 3 to 6 months, and yearly by clinical exam and color flow Doppler echocardiography.

Results. There were 4 deaths either in the hospital or within 30 days after surgery for an operative mortality of 3.6%. No patients experienced structural valve deterioration, non-structural valve deterioration, paravalvular leak, unacceptable hemodynamic performance, or postoperative endocarditis. The linearized rates for survival and thromboembolic complications at 5 years were 82.8% and 90.5% respectively. Excellent hemodynamic function is demonstrated by very low gradients, large EOA, and an exceedingly low incidence of any aortic regurgitation.

Conclusions. The Medtronic Freestyle aortic root bioprosthesis can be used safely to replace the aortic root for aortic valve and aortic root pathology. Root replacement allows optimal hemodynamic performance with no significant aortic regurgitation. Early and intermediate results are encouraging, but further follow-up is needed to determine valve durability.

Section snippets

Patients and methods

Wake Forest University Baptist Medical Center was selected in 1992 to serve as one of the United States study centers to begin implanting the Freestyle investigational valve. Before initiation of the study at our hospital, the institution’s investigational review board approved the study design. Written informed consent was obtained for each patient before operation prior to November 1997 FDA approval.

From September 17, 1992 to April 13, 1998, 112 patients received the Freestyle aortic root

Results

Patient improvement from preoperative to 1 year postoperative in NYHA class for congestive heart failure is depicted in Table 7. On clinical examination at the 1–year postoperative interval, 92.8% of patients were in class 1 and 4.8% were in class 2. No patients reaching 1 year were in class 3 or 4.

The mean cross–clamp time was 109.6 ± 13.1 minutes in patients who had isolated aortic root replacement and 128.6 ± 23.6 minutes in patients who had a concomitant procedure in addition to aortic

Comment

The non–physiologic flow through a stented bioprosthesis produces obstructive hemodynamics with resultant increased pressure gradients. Turbulent flow promotes micro–abrasions, platelet deposition, calcific degeneration, and may promote the development of prosthetic valve endocarditis.

The superior hemodynamics and improved late clinical outcomes for stentless porcine bioprostheses have been demonstrated 4, 11, 12, 13, 14, 15. The disadvantages of a stent include an increase in stress forces

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