Pericardial and porcine stentless aortic valves: are they hemodynamically different?

Continuous Suture Technique for Freedom Stentless Valve: Reduced Crossclamp Time

The Pericarbon Freedom stentless valve has shown excellent hemodynamics. A continuous suture technique at the inflow site may reduce cardiopulmonary bypass and crossclamp times and affect postoperative hemodynamics. In a prospective case-matched study, interrupted and continuous suture line techniques were used in 68 and 71 patients, respectively. Isolated valve replacement was performed in 70.4% of the continuous suture group and 67.6% of the interrupted suture group. Hemodynamic data were obtained by echocardiography (mean and peak gradients, regurgitation) at discharge and after 1 year. Overall mortality was 5.0% and due to non-valve-related causes. Bypass and crossclamp times were shorter by 22.4 and 20.6 min, respectively, in the continuous suture group. The suture technique at the inflow site did not result in significant differences in the mean (11.8 ± 6.3 vs. 12.5 ± 6.2 mm Hg) or peak gradients (21.0 ± 9.6 vs. 22.0 ± 10.9 mm Hg), or degree of regurgitation. Follow-up showed a further decrease in the gradients.

Recommendations for the implantation of the Pericarbon Freedom stentless valve

Based on our experience of 1000 subcoronary implants of the Sorin Pericarbon Freedom stentless valve, we give recommendations for the exact implantation technique. This article illustrates basic issues in the implantation technique with respect to continuous and interrupted suture to enable beginners and experienced surgeons to avoid some of the pitfalls. Additional remarks about sizing and early intraoperative echocardiographic findings complete this technical overview.

Impact of Stentless Aortic Valves on Left Ventricular Function and Hypertrophy: Current Best Available Evidence

Past four decades have seen a gradual evolution in aortic valve replacement surgery. The ideal valve substitute should combine central flow, low transvalvular gradient, low thrombogenicity, durability, easy availability, resistance to infection, freedom from anticoagulation, and easy implantability. Although there are several types of valves available to replace the diseased aortic valve-autograft, allograft, xenograft, mechanical, and bioprosthetic valves-none is ideal. On one end of the spectrum is the pulmonary autograft, which comes closest to achieving these goals, but creates a double valve procedure for single valve disease, while on the other end are the mechanical valves and stented tissue valves, which allow easy "off the shelf" availability as well as easy implantability but are limited by the potential drawback of causing intrinsic obstruction to some extent because of the space occupied by the stent and sewing ring. Stentless xenograft aortic valves have been developed as a compromise between these ends of the valve spectrum. Stentless aortic valves have been reported to provide more physiologic hemodynamic behavior and cause more timely and thorough regression of ventricular hypertrophy. This review article attempts to evaluate current best available evidence from randomized controlled trials to assess the impact of stentless aortic valves on left ventricular function and hypertrophy.

Single–suture line placement of a pericardial stentless valve

OBJECTIVE

Implantation of bioprostheses in the supra-annular position with the single suture line was first applied by O'Brien to porcine stentless valves. The aim of this study was to evaluate the clinical performance of the Pericarbon Freedom stentless bioprosthesis (Sorin Biomedica Cardio, Saluggia, Italy) implanted in supra-annular position with the single-suture line technique. The single-suture approach for the Pericarbon Freedom stentless bioprosthesis is obtained by trimming away all the extra tissue of the valve inflow side and scalloping the outflow side.

METHODS

Between February 2002 and August 2004, a total of 65 consecutive patients at our institution (48% male, mean age 69 +/- 12 years) underwent aortic valve replacement with Pericarbon Freedom stentless bioprostheses implanted with a single suture line. Most recurrent etiology was senile degeneration (80%). Pericarbon Freedom 25-mm and 27-mm valves were the most frequently implanted. Thirty patients had concomitant procedures (mainly coronary artery bypass grafting, 16 patients). Overall crossclamp time was 76 +/- 21 minutes.

RESULTS

All patients survived intervention. One patient died early of multiorgan failure (postoperative day 16). There were 4 early non-valve-related complications and no late complications at a mean follow-up of 491 +/- 270 days. Four patients showed trivial central prosthetic regurgitation at intraoperative transesophageal echocardiography; among these cases, only 1 was confirmed at 6-month transthoracic echocardiography. At postoperative echocardiographic assessment, mean pressure gradient for the 25- through 29-mm size group was 10.2 +/- 7.1 mm Hg, and peak pressure gradient was 18.1 +/- 12.3 mm Hg.

CONCLUSION

Our initial experience combined a well-established supra-annular implantation technique with the Pericarbon Freedom stentless bioprosthesis, a latest-generation pericardial stentless valve. The combination showed excellent results in terms of safety and reliability, although this technique required adequate experience. Clinical outcomes are similar to those obtained with other techniques, with satisfactory hemodynamic performance.

Usefulness of the Cryolife O'Brien stentless suprannular aortic valve to prevent prosthesis-patient mismatch in the small aortic root

OBJECTIVES

This study evaluated the occurrence of prosthesis-patient mismatch (PPM) after Cryolife O'Brien (CLOB) suprannular stentless valve replacement in patients with a small aortic root and its repercussions on the patient's hemodynamic status and left ventricular mass regression.

BACKGROUND

The correct management of the small aortic annulus is still controversial. Small aortic prostheses can lead to a PPM, which results in high gradients with important repercussions on the hemodynamic status.

METHODS

Seventy-two patients (mean age: 72.5 +/- 6.2 years, 73.6% women) with a small aortic root (< or =21 mm intraoperatively measured aortic annulus) had a CLOB valve implanted in the aortic position between November 1993 and July 2001 at our institution. Mean prosthesis size was 22.0 +/- 0.8 mm. Patients underwent echocardiography preoperatively, at discharge, six months, one year and yearly thereafter.

RESULTS

The incidence of PPM at discharge was 22.2% (16/72); 18.7% were severe (effective orifice area index [EOAI] < or =0.65 cm/m(2)), 43.7% were moderate (EOAI = 0.66 to 0.75 cm/m(2)) and 37.6% were mild (0.76 to 0.85 cm/m(2)). At multivariable analysis, gender (p < 0.001), age (p = 0.015), body surface area (p < 0.001) and patient's annulus index (p < 0.001) were significant factors influencing the occurrence of "transient" PPM. At one year the incidence of PPM was 0%. CONCLUSIONS; Suprannular CLOB valve yielded excellent hemodynamic results in patients with small aortic roots. This study demonstrates that PPM can be completely avoided when using the CLOB valve. The superior hemodynamics of this stentless valve are likely to be related to its suprannular design.

Stentless bioprostheses in aortic root disease

INTRODUCTION

The availability of aortic homografts is steadily decreasing. In the meantime, stentless xenografts convey similar flow characteristics, and tissue preservation methods are improving durability. Initially, these valves were contraindicated in aortic roots with discrepancy between annulus and sinotubular junction or with extensive calcification or sepsis. With increasing experience stentless xenografts are now applied in a wide spectrum of aortic root disease.

METHODS

I reviewed our own experience with stentless aortic bioprosthesis for aortic valve replacement (AVR) and more taxing root problems. I used these valves in aortic aneurysm repair, acute Type A dissection, and for endocarditis with abcess formation. I studied valve hemodynamics, regression of left ventricular hypertrophy, and comparative survival with stented bioprostheses.

RESULTS

Stentless bioprostheses convey hemodynamic and possibly survival benefit through a low incidence of valve-related complications. They provide a useful alternative to aortic homografts in endocarditis, Type A dissection, and aortic aneurysm surgery.

CONCLUSIONS

Stentless bioprostheses are no longer confined to AVR alone. Experience supports the use of stentless bioprostheses where aortic homografts were previously applied. With availability in a wide range of sizes.