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Objective

The aim of the study was to provide, by means of computational fluid dynamics, a comparative analysis after carotid endarterectomy (CEA) between patch graft (PG) and primary closure (PC) techniques performed in real carotid geometries to identify disturbed flow conditions potentially involved in the development of restenosis.

Methods

Eight carotid geometries in seven asymptomatic patients who underwent CEA were analyzed. In six cases (A-F), CEA was performed using PG closure; in two cases (G and H), PC was performed. Three-dimensional carotid geometries, derived from postoperative magnetic resonance angiography, were reconstructed, and a computational fluid dynamics analysis was performed. A virtual scenario with PC closure was designed in patients in whom PG was originally inserted and vice versa. This allowed us to compare for each patient hemodynamic effects in the PG and PC scenarios in terms of oscillatory shear index (OSI) and relative residence time (RRT), considered indicators of disturbed flow.

Results

For the six original PG cases, the mean averaged-in-space OSI was 0.07 ± 0.01 for PG and 0.03 ± 0.02 for virtual-PC (difference, 0.04 ± 0.01; P = .0016). The mean of the percentage of area (%A) with OSI >0.2 resulted in 10.08% ± 3.38% for PG and 3.80% ± 3.22% for virtual-PC (difference, 6.28 ± 1.91; P = .008). For the same cases, the mean of the averaged-in-space RRT resulted in 5.48 ± 3.40 1/Pa for PG and 2.62 ± 1.12 1/Pa for virtual-PC (difference, 2.87 ± 1.46; P = .097). The mean of %A RRT >4.0 1/Pa resulted in 26.53% ± 12.98% for PG and 9.95% ± 6.53% for virtual-PC (difference, 16.58 ± 5.93; P = .025). For the two original PC cases, the averaged-in-space OSIs were 0.02 and 0.04 for PC and 0.03 and 0.02 for virtual-PG; the %A OSIs >0.2 were 0.9% and 7.6% for PC and 3.0% and 2.2% for virtual-PG; the averaged-in-space RRTs were 1.8 and 2.0 1/Pa for PC and 2.9 and 1.9 1/Pa for virtual-PG; the %A RRTs >4.0 1/Pa were 6.8% and 9.8% for PC and 9.4% and 6.2% for virtual-PG. These results revealed generally higher disturbed flows in the PG configurations with respect to the PC ones.

Conclusions

OSI and RRT values were generally higher in PG cases with respect to PC, especially for high carotids or when the arteriotomy is mainly at the bulb region. Thus, an elective use of patch should be considered to prevent disturbed flows.  相似文献   
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Alan Getgood 《Arthroscopy》2018,34(9):2739-2742
Significant focus has recently been placed on the contribution of the anterolateral ligament (ALL) to controlling anterolateral rotatory laxity of the anterior cruciate ligament (ACL) injured knee. Many recent studies have investigated the use of magnetic resonance imaging and ultrasound on determining the degree of ALL injury and whether this is correlated to high-grade rotatory laxity. Unfortunately, most studies lack a reference standard, and as such it is challenging to determine whether it truly is the ALL that is injured or if the capsule-osseous layer and deep iliotibial band are involved. Historic literature has demonstrated the importance of these other structures having been noted to be injured at the time of ACL reconstruction. As such, it is clear that high-grade rotatory laxity does not result from an isolated ACL injury. We therefore must remain open to the idea that it is not just the ALL that may cause this injury pattern, and optimal solutions to address this patholaxity have yet to be fully determined.  相似文献   
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