Aortic Valve Area-Technical Communication: Continuity and Gorlin Equations Revisited

Development of Novel Sutureless Balloon Expandable Fetal Heart Valve Device Using Absorbable Polycaprolactone Leaflets

Congenital heart disease (CHD) accounts for nearly one-third of all congenital defects, and patients often require repeated heart valve replacements throughout their lives, due to failed surgical repairs and lack of durability of bioprosthetic valve implants. This objective of this study is to develop and in vitro test a fetal transcatheter pulmonary valve replacement (FTPVR) using sutureless techniques to attach leaflets, as an option to correct congenital defects such as pulmonary atresia with intact ventricular septum (PA/IVS), in utero. A balloon expandable design was analyzed using computational simulations to identify areas of failure. Five manufactured valves were assembled using the unique sutureless approach and tested in the fetal right heart simulator (FRHS) to evaluate hemodynamic characteristics. Computational simulations showed that the commissural loads on the leaflet material were significantly reduced by changing the attachment techniques. Hemodynamic analysis showed an effective orifice area of 0.08 cm2, a mean transvalvular pressure gradient of 7.52 mmHg, and a regurgitation fraction of 8.42%, calculated over 100 consecutive cardiac cycles. In conclusion, the FTPVR exhibited good hemodynamic characteristics, and studies with biodegradable stent materials are underway.

Novel Expansible Aortic Annuloplasty Ring Exhibits Similar Characteristics as the Dacron Ring-an In Vitro Evaluation

An increasing body of research indicates that annular stability plays a key role for a successful aortic valve repair. The aim of this study was to evaluate and compare a novel open aortic annuloplasty ring (the A-ring) with the Dacron ring. Both rings were compared with native aortic roots in vitro. Eighteen aortic roots were included in the study and randomized into three groups: the native, Dacron, and A-ring group. The roots were evaluated in an in vitro physiologic pulsatile model simulating the left side of the heart. Aortic annulus diameters were significantly reduced both in the Dacron ring group (p = 0.003) and the A-ring group (p = 0.020) when compared with the native group. Both the Dacron ring and A-ring effectively downsized the aortic annulus diameter. The A-ring also displayed an ability to maintain aortic root distensibility during the cardiac cycle equally to the Dacron ring.

The Year in Perioperative Echocardiography: Selected Highlights From 2019

This article is the fourth of an annual series reviewing the research highlights of the year pertaining to the subspecialty of perioperative echocardiography for the Journal of Cardiothoracic and Vascular Anesthesia. The authors thank the editor-in-chief, Dr. Kaplan, and the editorial board, for the opportunity to continue this series. In most cases, these were research articles that were targeted at the perioperative echocardiography diagnosis and treatment of patients after cardiothoracic surgery; but in some cases, these articles targetted the use of perioperative echocardiography in general.

Impact of left ventricular outflow tract flow acceleration on aortic valve area calculation in patients with aortic stenosis

Objective

Due to its circular shape, the area of the proximal left ventricular tract (PLVOT) adjacent to aortic valve can be derived from a single linear diameter. This is also the location of flow acceleration (FA) during systole, and pulse wave Doppler (PWD) sample volume in the PLVOT can lead to overestimation of velocity (V₁) and the aortic valve area (AVA). Therefore, it is recommended to derive V₁ from a region of laminar flow in the elliptical shaped distal LVOT (away from the annulus). Besides being inconsistent with the assumptions of continuity equation (CE), spatial difference in the location of flow and area measurement can result in inaccurate AVA calculation. We evaluated the impact of FA in the PLVOT on the accuracy of AVA by continuity equation (CE) in patients with aortic stenosis (AS).

Methods

CE-based AVA calculations were performed in patients with AS once with PWD-derived velocity time integral (VTI) in the distal LVOT (VTI_LVOT) and then in the PLVOT to obtain a FA velocity profile (FA-VTI_LVOT) for each patient. A paired sample t-test (P < 0.05) was conducted to compare the impact of FA-VTI_LVOT and VTI_LVOT on the calculation of AVA.

Result

There were 46 patients in the study. There was a 30.3% increase in the peak FA-VTI_LVOT as compared to the peak VTI_LVOT and AVA obtained by FA-VTI_LVOT was 29.1% higher than obtained by VTI_LVOT.

Conclusion

Accuracy of AVA can be significantly impacted by FA in the PLVOT. LVOT area should be measured with 3D imaging in the distal LVOT.