The Role of Branch Vessels in Aortic Type B Dissection: An in vitro Study

Background Medical treatment of initially uncomplicated acute Stanford type-B aortic dissection is associated with a high rate of late adverse events. Identification of individuals who potentially benefit from preventive endografting is highly desirable. Methods and Results The association of CT imaging features with late adverse events was retrospectively assessed in 83 patients with acute uncomplicated Stanford type-B aortic dissection, followed over a median of 850 (IQR 247–1824) days. Adverse events were defined as fatal or non-fatal aortic rupture, rapid aortic growth (>10 mm/year), aneurysm formation (≥6 cm), organ or limb ischemia, or new uncontrollable hypertension or pain. Five significant predictors were identified using multivariable Cox regression analysis: connective tissue disease (HR 2.94, 95%CI: 1.29–6.72, p=0.01), circumferential extent of false lumen in angular degrees (HR 1.03 per degree, 95%CI: 1.01–1.04, p=0.003), maximum aortic diameter (HR 1.10 per mm, 95%CI: 1.02–1.18, p=0.015), false lumen outflow (HR 0.999 per mL, 95%CI: 0.998–1.000, p=0.055), and number of intercostal arteries (HR 0.89 per n, 95%CI: 0.80–0.98, p=0.024). A prediction model constructed to calculate patient specific risk at 1, 2 and 5 years and to stratify patients into high, intermediate, and low risk groups. The model was internally validated by bootstrapping and showed good discriminatory ability with an optimism-corrected c-statistic of 70.1%. Conclusions CT imaging-based morphologic features combined into a prediction model may be able to identify patients at high risk for late adverse events after an initially uncomplicated type B aortic dissection.

show abstract

“…These concepts have been proposed 60 years ago by Shaw 43 and De Bakey 44 and are currently finding a revival. 41,45 …”

Section: Discussionmentioning

confidence: 99%

Computed Tomography Imaging Features in Acute Uncomplicated Stanford Type-B Aortic Dissection Predict Late Adverse Events

Sailer

Kuijk

Nelemans

et al. 2017

Circ: Cardiovascular Imaging

View full text Add to dashboard Cite

show abstract

“…Since many AD patients have visceral side branches (including important ones such as the celiac trunk) originating from the FL, and this was reported to be significant related to aortic enlargement [ 5 , 29 ], we assessed their influence on flow. Our results showed that the incidence of FL side branches increased the amount of FL flow volume and affected FL flow direction, so that FL flows became more unidirectional (mostly antegrade or retrograde depending on the level of the dissection), primarily affecting the percentage of retrograde diastolic FL flow.…”

Section: Discussionmentioning

confidence: 99%

False Lumen Flow Patterns and their Relation with Morphological and Biomechanical Characteristics of Chronic Aortic Dissections. Computational Model Compared with Magnetic Resonance Imaging Measurements

et al. 2017

View full text Add to dashboard Cite

Aortic wall stiffness, tear size and location and the presence of abdominal side branches arising from the false lumen (FL) are key properties potentially involved in FL enlargement in chronic aortic dissections (ADs). We hypothesize that temporal variations on FL flow patterns, as measured in a cross-section by phase-contrast magnetic resonance imaging (PC-MRI), could be used to infer integrated information on these features. In 33 patients with chronic descending AD, instantaneous flow profiles were quantified in the FL at diaphragm level by PC-MRI. We used a lumped-parameter model to assess the changes in flow profiles induced by wall stiffness, tear size/location, and the presence of abdominal side branches arising from the FL. Four characteristic FL flow patterns were identified in 31/33 patients (94%) based on the direction of flow in systole and diastole: BA = systolic biphasic flow and primarily diastolic antegrade flow (n = 6); BR = systolic biphasic flow and primarily diastolic retrograde flow (n = 14); MA = systolic monophasic flow and primarily diastolic antegrade flow (n = 9); MR = systolic monophasic flow and primarily diastolic retrograde flow (n = 2). In the computational model, the temporal variation of flow directions within the FL was highly dependent on the position of assessment along the aorta. FL flow patterns (especially at the level of the diaphragm) showed their characteristic patterns due to variations in the cumulative size and the spatial distribution of the communicating tears, and the incidence of visceral side branches originating from the FL. Changes in wall stiffness did not change the temporal variation of the flows whereas it importantly determined intraluminal pressures. FL flow patterns implicitly codify morphological information on key determinants of aortic expansion in ADs. This data might be taken into consideration in the imaging protocol to define the predictive value of FL flows.

show abstract

“…Our in vitro circulatory system was previously validated with respect to simulating the human circulatory system. [19][20][21][22] Fig 1 shows a systematic representation of the in vitro circulatory system, which consists of a pneumatically driven pulsatile pump, a ball valve, a compliance air chamber, an arterial stenosis model (a removable tube for inserting the stenosis), a pressure band to simulate peripheral resistance, and a collateral system with intrinsic peripheral resistance. The following degrees of stenosis were used at two different lengths (2 and 8 cm): 50%, 70%, 80%, and 90%; these stenosis models were easily switched in the arterial stenosis model.…”

Section: Methodsmentioning

confidence: 99%

Using maximal systolic acceleration to diagnose and assess the severity of peripheral artery disease in a flow model study

Brouwers

Doorn

Wissen

et al. 2020

Journal of Vascular Surgery

View full text Add to dashboard Cite

Background: Because of the presence of medial calcific sclerosis, both ankle-branchial index and toe pressure measures can yield misleading results when attempting to diagnose peripheral artery disease (PAD). A new ultrasound parameter, maximal systolic acceleration (ACC max ), can be an accurate tool for diagnosing PAD, including in diabetic patients. However, it has not been evaluated thoroughly. The aim of this study was to assess the feasibility of using ACC max to diagnose and assess the severity of PAD.Methods: The human circulatory system was simulated using an in vitro circulatory system driven by a pulsatile pneumatic pump. Arterial stenosis of various degrees (50%, 70%, 80%, and 90%) was simulated in order to investigate the change in several ultrasound parameters (including ACC max ), as well as the intraluminal mean arterial pressure gradient. In a separate set of measurements, interobserver variability was measured using two investigators who were unaware of the degree of stenosis.Results: ACC max significantly decreased (P < .001), and the pressure gradient increased (P < .001) as the degree of stenosis increased. Moreover, we found a strong correlation between ACC max and the pressure gradient (R 2 ¼ 0.937). Finally, interobserver variability with respect to ACC max was extremely low, with an intraclass correlation coefficient of 0.99. Conclusions:The results of this flow model study suggest that ACC max can be a valid, noninvasive tool for diagnosing PAD. Moreover, our finding that ACC max decreases as the severity of stenosis increases, together with the strong correlation between ACC max and the pressure gradient, suggests that ACC max may be useful as an alternative diagnostic tool for assessing the severity of PAD. These promising in vitro data warrant further study in a clinical setting. (J Vasc Surg 2020;71:242-9.)Clinical Relevance: Limb pressure measurements and the determination of pressure index values (ankle-branchial index and toe pressure) are commonly used in patients with symptoms consistent with peripheral arterial disease. However, ankle-branchial index and toe pressure can be falsely elevated or falsely normal due to medial calcific sclerosis. In this in vitro flow-model study, the maximal systolic acceleration (ACC max ) significantly decreased as the degree of stenosis increased. Furthermore, there was a strong correlation between ACC max and the intraluminal pressure gradient. These results suggest ACC max may provide a robust noninvasive technique for assessing the severity of peripheral arterial disease.

show abstract

The Role of Branch Vessels in Aortic Type B Dissection: An in vitro Study

Abstract: Increasing antegrade outflow through a branch vessel originating from the false lumen when no distal re-entry tear is present results in an expansion of the cross sectional false lumen area.

Cited by 14 publications

References 23 publications

Computed Tomography Imaging Features in Acute Uncomplicated Stanford Type-B Aortic Dissection Predict Late Adverse Events

Computed Tomography Imaging Features in Acute Uncomplicated Stanford Type-B Aortic Dissection Predict Late Adverse Events

False Lumen Flow Patterns and their Relation with Morphological and Biomechanical Characteristics of Chronic Aortic Dissections. Computational Model Compared with Magnetic Resonance Imaging Measurements

Using maximal systolic acceleration to diagnose and assess the severity of peripheral artery disease in a flow model study

Contact Info

Product

Resources

About