Intra-Supra Annular Aortic Valve and Complete Supra Annular Aortic Valve: A Literature Review and Hemodynamic Comparison

Managing the challenge of a small aortic annulus in patients with severe aortic stenosis

INTRODUCTION

Small aortic annulus (SAA) poses a challenge in the management of patients with severe aortic stenosis requiring aortic valve replacement - both surgical and transcatheter - since it has been associated with worse clinical outcomes.

AREAS COVERED

This review aims to comprehensively summarize the available evidence regarding the management of aortic stenosis in patients with SAA and discuss the current controversies as well as future perspectives in this field.

EXPERT OPINION

It is paramount to agree in a common definition for diagnosing and properly treating SAA patients, and for that purpose, multidetector computer tomography is essential. The results of recent trials led to the expansion of transcatheter aortic valve replacement among patients of all the surgical-risk spectrum, and the choice of treatment (transcatheter, surgical) should be based on patient comorbidities, anatomical characteristics, and patient preferences.

Simple Interrupted Suturing for Aortic Valve Replacement in Patients with Severe Aortic Stenosis

Background

Attaining an adequate effective orifice area (EOA) is definitive goal in aortic valve replacement (AVR). The simple interrupted suture (SIS) technique could be a solution to achieve this goal, but limited data are available in the literature. This study aimed to compare hemodynamic differences between the SIS and non-everting mattress suture (NMS) techniques.

Methods

From our database, 215 patients who underwent AVR for severe aortic stenosis were extracted to form the overall cohort. From March 2015 to November 2016, the SIS technique was used in 79 patients, while the NMS technique was used in 136 patients. Hemodynamic outcomes were evaluated, as detected by transthoracic echocardiography and computed tomography.

Results

There were no significant differences in baseline characteristics between the 2 groups. On immediate postoperative echocardiography, the SIS group showed a significantly wider EOA (1.6±0.4 vs. 1.4±0.5 cm², p=0.007) and a lower mean pressure gradient (PG) (13.3±5.4 vs. 17.0±6.0 mm Hg, p<0.001) than the NMS group. On follow-up echocardiography, the SIS group continued to have a wider EOA (1.6±0.4 vs. 1.4±0.3 cm², p<0.001) and a lower mean PG (11.0±5.1 vs. 14.1±5.5 mm Hg, p<0.001). There was no significant difference in paravalvular leakage.

Conclusion

The SIS technique for AVR was associated with a wider EOA and a lower mean PG. The SIS technique could be a reasonable option for AVR.

Supra-annular versus intra-annular prostheses in aortic valve replacement: impact on haemodynamics and clinical outcomes

OBJECTIVES

The superiority of supra-annular aortic prostheses over intra-annular equivalents in long-term haemodynamics and clinical outcomes remains controversial. This study compared outcomes among patients receiving supra-annular or intra-annular prostheses during aortic valve replacement.

METHODS

We enrolled 587 consecutive patients (mean age 55.1 ± 11.3 years; 188 women) undergoing aortic valve replacement with either supra-annular (n = 316) or intra-annular (n = 271) mechanical prostheses between 2000 and 2016 in our institute. Clinical outcomes and haemodynamic profiles in the 2 groups were compared after propensity score adjustment.

RESULTS

Early death (1.1% vs 0.6%; P = 0.863) was equivalent for both groups. Patients receiving supra-annular prostheses showed a lower rate of patient-prosthesis mismatch (1.2% vs 25.8%; P < 0.001). During a median follow-up of 65 months (quartile 1-3, 30-108 months), overall deaths occurred in 84 (14.3%) patients. The latest echocardiographic assessment in the 136 propensity score-matched pairs demonstrated superior haemodynamics with implantation of supra-annular prostheses: peak velocity (2.7 ± 0.6 vs 2.3 ± 0.5 m/s; P < 0.001), mean pressure gradient (16.5 ± 9.0 vs 12.0 ± 6.2 mmHg; P < 0.001) and left ventricular mass index (113.6 ± 30.3 vs 105.3 ± 26.3 g/m2; P = 0.016). After adjusting with inverse-probability-of-treatment weighting, however, the choice of supra-annular over intra-annular prosthesis did not significantly affect the risk of overall mortality (P = 0.693) or major adverse events: stroke (P = 0.944), infective endocarditis (P = 0.958) and reoperation (P = 0.944).

CONCLUSIONS

The implantation of supra-annular prostheses resulted in superior haemodynamics and left ventricular mass regression, while conferring no apparent clinical benefits. Follow-up studies are required to further evaluate the impact of superior haemodynamics associated with supra-annular prostheses on long-term clinical outcomes.

Laser Doppler anemometry measurements of steady flow through two bi-leaflet prosthetic heart valves

Introduction

In vitro hydrodynamic characterization of prosthetic heart valves provides important information regarding their operation, especially if performed by noninvasive techniques of anemometry. Once velocity profiles for each valve are provided, it is possible to compare them in terms of hydrodynamic performance. In this first experimental study using laser doppler anemometry with mechanical valves, the simulations were performed at a steady flow workbench.

Objective

To compare unidimensional velocity profiles at the central plane of two bi-leaflet aortic prosthesis from St. Jude (AGN 21 - 751 and 21 AJ - 501 models) exposed to a steady flow regime, on four distinct sections, three downstream and one upstream.

Methods

To provide similar conditions for the flow through each prosthesis by a steady flow workbench (water, flow rate of 17L/min. ) and, for the same sections and sweeps, to obtain the velocity profiles of each heart valve by unidimensional measurements.

Results

It was found that higher velocities correspond to the prosthesis with smaller inner diameter and instabilities of flow are larger as the section of interest is closer to the valve. Regions of recirculation, stagnation of flow, low pressure, and flow peak velocities were also found.

Conclusions

Considering the hydrodynamic aspect and for every section measured, it could be concluded that the prosthesis model AGN 21 - 751 (RegentTM) is superior to the 21 AJ - 501 model (Master Series). Based on the results, future studies can choose to focus on specific regions of the these valves.