Purpose: To describe the concept of aortic elastic deformation (ED) measurement using duplex ultrasonography (DUS) as a tool for detection of high aneurysm sac pressure following endovascular... Show morePurpose: To describe the concept of aortic elastic deformation (ED) measurement using duplex ultrasonography (DUS) as a tool for detection of high aneurysm sac pressure following endovascular aortic repair (EVAR). Technique: High aneurysm sac pressure, with or without proven endoleak, will result in a less compressible aneurysm. Using the dual image function in B-mode of the DUS device and a standardized amount of applied probe pressure, ED can be measured. It is defined as the percentage of deformation of the aneurysm sac on probe pressure application. We hypothesize that less ED of the aneurysm sac can be related with high aneurysm sac pressure and possibly the presence of clinically relevant endoleak. In this note, we describe the technical details of the procedure and report on the applicability and results of ED measurements in the framework of aortic aneurysm and EVAR follow-up in a cohort of 109 patients. Conclusion: ED measurement is the first noninvasive pressure-based method in the quest to find a practical and reliable diagnostic tool to exclude high aneurysm sac pressure. In our patient cohort, patients with proven endoleak showed a smaller ED (less compressible), implying the presence of high aneurysm sac pressure. Further research should confirm whether ED measurement using DUS could reliably exclude endoleak after EVAR and further explore its potential for clinical application in EVAR follow-up. Clinical Impact For the first time, a simple, fast, and inexpensive diagnostic tool is presented in this study for detecting high sac pressure following EVAR. High sac pressure is typically caused by clinically significant endoleaks, which can have significant consequences. Currently, computed tomography scanning is the most common method used to identify and characterize endoleaks. However, measuring elastic deformation may potentially replace more invasive and expensive modalities, such as the computed tomography in the future. Show less
Objective: Doppler ultrasonography (DUS) is used as initial measurement to diagnose and classify carotid artery stenosis. Local distorting factors such as vascular calcification can influence the... Show moreObjective: Doppler ultrasonography (DUS) is used as initial measurement to diagnose and classify carotid artery stenosis. Local distorting factors such as vascular calcification can influence the ability to obtain DUS measurements. The DUS derived maximal systolic acceleration (ACCmax) provides a different way to determine the degree of stenosis. While conventional DUS parameters are measured at the stenosis itself, ACCmax is measured distal to the internal carotid artery (ICA) stenosis. The value of ACCmax in ICA stenosis was investigated in this study. Material and Methods: All carotid artery DUS studies of a tertiary academic center were reviewed from October 2007 until December 2017. Every ICA was included once. The ACCmax was compared to conventional DUS parameters: ICA peak systolic velocity (PSV), and PSV ratio (ICA PSV/CCA PSV). ROC-curve analysis was used to evaluate accuracy of ACCmax, ICA PSV and PSV ratio as compared to CT-angiography (CTA) derived stenosis measurement as reference test. Results: The study population consisted of 947 carotid arteries and was divided into 3 groups: <50% (710/947), 50-69% (109/947), and >= 70% (128/947). Between these groups ACCmax was significantly different. Strong correlations between ACCmax and ICA PSV (R-2 0.88) and PSV ratio (R-2 0.87) were found. In ROC subanalysis, the ACCmax had a sensitivity of 90% and a specificity of 89% to diagnose a >= 70% ICA stenosis, and a sensitivity of 82% and a specificity of 88% to diagnose a >= 50% ICA stenosis. For diagnosing a >= 50% ICA stenosis the area under the curve (AUC) of ACCmax (0.88) was significantly lower than the AUC of PSV ratio (0.94) and ICA PSV (0.94). To diagnose a >= 70% ICA stenosis there were no significant differences in AUC between ACCmax (0.89), PSV ratio (0.93) and ICA PSV (0.94). Conclusions: ACCmax is an interesting additional DUS measurement in determining the degree of ICA stenosis. ACCmax is measured distal to the stenosis and is not hampered by local distorting factors at the site of the stenosis. ACCmax can accurately diagnose an ICA stenosis, but was somewhat inferior compared to ICA PSV and PSV ratio to diagnose a >= 50% ICA stenosis. Show less
Background: In diagnosing peripheral arterial disease (PAD), medial arterial calcification (MAC) hampers arterial compression and could lead to unreliable ankle brachial index (ABI), toe brachial... Show moreBackground: In diagnosing peripheral arterial disease (PAD), medial arterial calcification (MAC) hampers arterial compression and could lead to unreliable ankle brachial index (ABI), toe brachial index (TBI) and toe pressure (TP). Doppler ultrasonography (DUS) derived maximal systolic acceleration (ACCmax) might be more accurate to diagnose PAD. In an in vitro study, a strong correlation between ACCmax and the severity of stenotic disease was determined. The aim of this study was to investigate the ACCmax in correlation with conventional non-invasive diagnostics in an in vivo setting. Methods: In twelve healthy individuals, an arterial stenosis was mimicked by compression on the common femoral artery by an ultrasounds probe, creating a local stenosis of 50%, 70% and 90%. The ABI, TBI, TP and several DUS parameters (including ACCmax) were assessed at the ankle during these different degrees of stenosis. All DUS parameters were measured separately by two observers to determine the interobserver variability. Results: Overall the ABI, TBI, TP, ACCmax, ACCsys and PSV decreased significantly when the degree of stenosis increased. The ACCmax showed the highest correlation with the degree of stenosis (r -.884), compared to ABI (r -.726), TBI (r -.716) and TP (r -.758). Furthermore, the interobserver variability of ACCmax was excellent, with an intraclass correlation coefficient (ICC) of .97. Conclusion: ACCmax is an accurate non-invasive DUS parameter to diagnose and assess the severity of a mimicked arterial stenosis in healthy individuals. Further prospective assessment of the clinical value of ACCmax and its potential benefits in patients with PAD is needed. Show less
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... Show moreBackground: 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 = 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. Show less
Aim The aim of this study was to assess the diagnostic accuracy of the Doppler derived maximal systolic acceleration (ACC(max)) as a novel technique for evaluating peripheral arterial occlusive... Show moreAim The aim of this study was to assess the diagnostic accuracy of the Doppler derived maximal systolic acceleration (ACC(max)) as a novel technique for evaluating peripheral arterial occlusive disease (PAOD) in patients with diabetes mellitus, who are known for a falsely elevated ankle-brachial index (ABI). Methods. In this retrospective analysis ACC(max) was measured at ankle level in a series of 163 consecutive patients referred to the vascular laboratory for initial assessment of PAOD. Patients were classified according to the presence or absence of diabetes. In the non-diabetic patients PAOD was defined as ABI <= 0.90. This group was used to establish the association between ACC(max) and ABI in a linear regression model. The result was then used to predict the presence or absence of PAOD in the diabetic patients. Results. The authors examined 301 lower limbs. The study group consisted of 166 limbs of patients without diabetes and 135 limbs of patients with diabetes. PAOD was present in 52% of limbs in the nondiabetic group versus 59% of limbs in the diabetic group (ABI <= 0.90, or in case of non-compliant vessels toe-brachial index (TBI) <= 0.70). An ACC(max) cut-off value of >10 m/s(2) was found to be highly predictive for the exclusion of PAOD (negative predictive value 95%). In addition, the ACC(max) cut-off value of <6.5 m/s(2) was highly predictive for the detection of PAOD (positive predictive value 99%). A strong quadratic association was found between ACC(max) and ABI in the non-diabetic group (R-2=0.85). In the diabetic patients R-2 values were 0.81 and 0.79 after ABI and TBI measurement respectively. Conclusion. DUS-derived ACC(max) an accurate marker that could offer significant benefits for the diagnosis of PAOD, especially in diabetic patients. Show less
