In vitro study of the aortic interleaflet triangle reshaping

Abstract

Aortic interleaflet triangle reshaping (AITR) is a surgical approach to aortic valve incontinence that involves placing three stitches at half of the interleaflet triangles height. In this work, the relationship between the actual stitch height and valve functioning, and the safety margin that the surgeon can rely on in applying the stitches were systematically investigated in vitro. AITR surgery was applied to six swine aortic roots placing the stitches empirically at 50%, 60% and 75% of the triangle heights. Then the actual stitch heights were measured and the hydrodynamic performances were evaluated with a pulsatile hydrodynamic mock loop. Actual stitch heights were 45±2%, 61±4% and 79±6%. As compared to untreated conditions, the 50% configuration induced a significant variation in the effective orifice area. With stitches placed at 60%, the mean systolic pressure drop increased significantly with respect to the untreated case, but no significant changes were recorded with respect to the 50% configuration. At 75%, all the hydrodynamic parameters of systolic valve functioning worsened significantly. Summarizing, the AITR technique, when performed in a conservative manner did not induce significant alterations in the hydrodynamics of the aortic root in vitro, while more aggressive configurations did. The absence of a statistically significant difference between the 50% and 60% configurations suggests that there is a reasonably limited risk of inducing valve stenosis in the post-op scenario due to stitch misplacement.

A Novel Insight into the Role of Entry Tears in Type B Aortic Dissection: Pressure Measurements in an in Vitro Model

“…See for example (27), which includes a review of the literature on mock loop systems up to 2009 and does not employ blood, and (28), where a discussion about the fluid is included. Moreover, the tendency to use water is confirmed also in more recent papers, (e.g., (33)). On the other hand, the impact of the reduced viscosity on our analyses is discussed later in the results section.…”

Comparison of the Performance of a Sutureless Bioprosthesis With Two Pericardial Stented Valves on Small Annuli: An In Vitro Study

“…The mock loop used in this study, FoRCardioLab (Foundation for Research in Cardiac Surgery, Milan, Italy), has been already described in detail [11][12][13]. In brief, the loop consists of a computer-controlled volumetric pump that can replicate left ventricular flow wave forms, a sample test section in which is housed a swine aortic root unit (ARU), and an adjustable hydraulic afterload mimicking the hydraulic impedance of the systemic circulation.…”

“…The ARU samples were harvested by two experienced surgeons and prepared as described previously [3,[11][12][13].…”

Fluid dynamics of aortic root dilation in Marfan syndrome

“…Other studies have been performed in-vitro granting repeatability of the conditions at the cost of a schematic reproduction of morphology (Brücker et al, 2002;Chandran et al, 1985;Gülan et al, 2012;Hutchison et al, 2011;Leo et al, 2012;Lim et al, 2001;Yoganathan et al, 1979). Recently, investigations have been carried out using passively driven, ex-vivo models (Leopaldi et al, 2012;Richards et al, 2009;Vismara et al, 2014), which are optimal in reproducing realistic anatomy but suffers from individual variability and do not permit the application of image velocimetry techniques since they do not allow optical access to the flow. The main purpose of most of the studies about the fluid dynamics of the aortic root was to assess the performances of prosthetic valves.…”