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  • Author: Fabio Dell’Avvocata x
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Open access

Gianluca Rigatelli, Fabio dell’Avvocata, Beatrice Magro and Stefano Panin

Abstract

Patients with simple congenital heart disease such as isolated atrial septal defects (ASDs) are rapidly becoming a relatively large population with a variety of clinical problems that are often missed by pediatric physicians or grown up congenital heart disease specialists, and may involve different adult health professionals such as general cardiologists or internists. Isolated ASDs are common (7% of all cardiac anomalies) and can present at any age, sometimes in conjunction with other genetic disorders such as Down’s syndrome or in a familiar form. The diagnosis is often accidental: Doppler echocardiography and, recently, magnetic resonance imaging are mandatory to assess types and significance of ASDs. Surgical or percutaneous repair should be offered at any age unless associated with pulmonary vascular disease: Percutaneous closure should be preferred in isolated secundum ASD with sufficient rims on trans-esophageal echocardiography, whereas surgery remains the only option for primum and sinus defects. Follow-up of operated patients is based on Holter EKG and echocardiography that should be scheduled every 2 years for secundum and sinus defects and every year for primum defect with valve repair. ASDs in adolescents and adults may be suspected in any physician’s office and doctors should be acquainted with innovative imaging techniques and contemporary therapeutic options in order to deliver proper care to different types of ASDs and assist them after repair with appropriate follow-up strategies.

Open access

Gianluca Rigatelli, Marco Zuin, Fabio Dell’Avvocata, Aravinda Nanjundappa, Ramesh Daggubati and Thach Nguyen

Abstract

Objectives

To non-invasively evaluate by computational fluid dynamic (CFD) analysis the physiology and rheology of aortoiliac bifurcation disease at different angles and different stent configurations.

Material and methods

For the analysis, we considered a physiologic model of abdominal aorta with an iliac bifurcation set at 30°, 45° and 70° without stenosis. Subsequently, a bilateral ostial common iliac stenosis of 80% was considered for each type of bifurcation. For the stent simulation, we reconstructed Zilver vascular self-expanding (Zilver; Cook, Bloomington, MN) and Palmaz Genesis Peripheral (Cordis, Miami, FL) stents.

Results

The physiologic model, across the different angles, static pressure, Reynolds number and stream function, were lower for the 30° bifurcation angle with a gradient from 70° to 30° angles, whereas all the other parameters were inversely higher. After stenting, all the fluid parameters decreased homogenously independent of the stent type, maintaining a gradient in favour of 30° compared to 45° and 70° angles. The absolute greater deviation from physiology was observed for low kissing when self-expandable stents were used across all angles; in particular, the wall shear stress was high at at 45° angle.

Conclusion

Bifurcation angle deeply impacts the physiology of aortoiliac bifurcations, which are used to predict the fluid dynamic profile after stenting. CFD, having the potential to be derived both from computed tomography scan or invasive angiography, appears to be an ideal tool to predict fluid dynamic profile before and after stenting in aortoiliac bifurcation.

Open access

Gianluca Rigatelli, Fabio Dell’Avvocata, Marco Zuin, Sara Giatti, Khanh Duong, Trung Pham, Nguyen Si Tuan, Dobrin Vassiliev, Ramesh Daggubati and Thach Nguyen

Abstract

Background and Objectives

Provisional and culotte are the most commonly used techniques in left main (LM) stenting. The impact of different post-dilation techniques on fluid dynamic of LM bifurcation has not been yet investigated. The aim of this study is to evaluate, by means of computational fluid dynamic analysis (CFD), the impact of different post-dilation techniques including proximal optimization technique (POT), kissing balloon (KB), POT-Side-POT and POT–KB-POT, 2-steps Kissing (2SK) and Snuggle Kissing balloon (SKB) on flow dynamic profile after LM provisional or culotte stenting.

Methods

We considered an LM-LCA-LCX bifurcation reconstructed after reviewing 100 consecutive patients (mean age 71.4 ± 9.3 years, 49 males) with LM distal disease. The diameters of LAD and LCX were modelled according to the Finnet’s law as following: LM 4.5 mm, LAD 3.5 mm, LCX 2.75 mm, with bifurcation angle set up at 55°. Xience third-generation stent (Abbot Inc., USA) was reconstructed and virtually implanted in provisional/cross-over and culotte fashion. POT, KB, POT-side-POT, POT-KB-POT, 2SK and SKB were virtually applied and analyzed in terms of the wall shear stress (WSS).

Results

Analyzing the provisional stenting, the 2SK and KB techniques had a statistically significant lower impact on the WSS at the carina, while POT seemed to obtain a neutral effect. In the wall opposite to the carina, the more physiological profile has been obtained by KB and POT with higher WSS value and smaller surface area of the lower WSS. In culotte stenting, at the carina, POT-KB-POT and 2SK had a very physiological profile; while at the wall opposite to the carina, 2SK and POT–KB-POT decreased significantly the surface area of the lower WSS compared to the other techniques.

Conclusion

From the fluid dynamic point of view in LM provisional stenting, POT, 2SK and KB showed a similar beneficial impact on the bifurcation rheology, while in LM culotte stenting, POT-KB-POT and 2SK performed slightly better than the other techniques, probably reflecting a better strut apposition.