OBJECTIVE: Robot-assisted systems offer an opportunity to support the diagnostic and therapeutic treatment of vascular diseases to reduce radiation exposure and support the limited medical staff in vascular medicine. In the diagnosis and follow-up care of vascular pathologies, Doppler ultrasound has become the preferred diagnostic tool. The study presents a robotic system for automatic Doppler ultrasound examinations of patients\' leg vessels.
METHODS: The robotic system consists of a redundant 7 DoF serial manipulator, to which a 3D ultrasound probe is attached. A compliant control was employed, whereby the transducer was guided along the vessel with a defined contact force. Visual servoing was used to correct the position of the probe during the scan so that the vessel can always be properly visualized. To track the vessel\'s position, methods based on template matching and Doppler sonography were used.
RESULTS: Our system was able to successfully scan the femoral artery of seven volunteers automatically for a distance of 20 cm. In particular, our approach using Doppler ultrasound data showed high robustness and an accuracy of 10.7 (±3.1) px in determining the vessel\'s position and thus outperformed our template matching approach, whereby an accuracy of 13.9 (±6.4) px was achieved.
CONCLUSIONS: The developed system enables automated robotic ultrasound examinations of vessels and thus represents an opportunity to reduce radiation exposure and staff workload. The integration of Doppler ultrasound improves the accuracy and robustness of vessel tracking, and could thus contribute to the realization of routine robotic vascular examinations and potential endovascular interventions.

BACKGROUND: Duplex sonographic visualization of a retrogradely perfused ophthalmic artery (AO) as an expression of an existing collateral supply in high-grade stenosis of the internal carotid artery (ACI) is a widely used and validated tool. After revascularization there may be another reversal of flow. Recently, the question of whether knowledge of the flow direction of the AO before and after implantation of a stent can be used as an outcome predictor has been posed more frequently.
RESULTS: In this article, the method of duplex sonographic assessment of the AO is explained more elaborately and we present a case of a patient with 75% restenosis of the left ACI with contralateral chronic occlusion of the right ACI. We focus on the special aspect that the ipsilateral AO was initially perfused retrogradely and that postinterventionally there was a flow reversal to a physiological anterograde flow. The case report is used to illustrate the value of duplex sonographic visualization of the AO.
CONCLUSIONS: Our case report is able to illustrate two aspects: On the one hand, the AO can be perfused retrogradely in the specific case of chronic ACI occlusion of the opposite side, even when the ACI stenosis of the considered side is less than 80%. On the other hand, the AO can offer added diagnostic value as a follow-up parameter for re- or in-stent stenoses.
UNASSIGNED: HINTERGRUND: Die duplexsonographische Darstellung einer retrograden A. ophthalmica (AO) als Ausdruck einer bestehenden Kollateralversorgung bei hochgradigen Stenosen der A. carotis interna (ACI) ist ein hinlänglich genutztes und validiertes Werkzeug. Nach Revaskularisierung kann es zu einer erneuten Flussumkehr kommen. In jüngerer Vergangenheit wurde sich vermehrt der Fragestellung zugewandt, ob die Kenntnis über die Flussrichtung der AO vor und nach einer Stentimplantation als Outcomeprädiktor genutzt werden kann.
UNASSIGNED: Im vorliegenden Artikel wird die Methodik der duplexsonographischen Beurteilung der AO näher erläutert und ein Fallbeispiel eines Patienten mit einer 75 %igen Restenose der ACI links mit kontralateralem chronischem Verschluss der ACI rechts aufgeführt. Dabei wird ein Augenmerk auf die Besonderheit gelegt, dass die ipsilaterale AO initial retrograd perfundiert war und sich postinterventionell eine Umkehr zum physiologischen anterograden Fluss zeigte. Anhand des Fallbeispiels wird der Stellenwert der duplexsonographischen Darstellung der AO resümiert.
CONCLUSIONS: Unser Fallbeispiel zeigt im Wesentlichen zwei Aspekte: Zum einen kann die AO in der spezifischen Situation, in der ein chronischer ACI-Verschluss der Gegenseite vorliegt, auch bei einer ACI-Stenose von unter 80 % retrograd perfundiert sein. Zum anderen kann die AO als Verlaufsparameter bei Re- bzw. In-Stent-Stenosen einen diagnostischen Mehrwert bieten.

UNASSIGNED: Accurate assessment of carotid stenosis severity is important for proper patient management. The present study aimed to compare the evaluation of carotid stenosis severity using four duplex sonography (DUS) measurements, including peak systolic velocity (PSV), PSV ratio in stenosis and distal to stenosis (PSVICA/ICA ratio), end-diastolic velocity (EDV), and B-mode, with computed tomography angiography (CTA), and to evaluate the impact of plaque morphology on correlation between DUS and CTA.
UNASSIGNED: Consecutive patients with carotid stenosis of ≥40% examined using DUS and CTA were included. Plaque morphology was also determined using magnetic resonance imaging. Spearman\'s correlation and Kendall\'s rank correlation were used to evaluate the results.
UNASSIGNED: A total of 143 cases of internal carotid artery stenosis of ≥40% based on DUS were analyzed. The PSVICA/ICA ratio showed the highest correlation [Spearman\'s correlation r = 0.576) with CTA, followed by PSV (r = 0.526), B-mode measurement (r = 0.482), and EDV (r = 0.441; p < 0.001 in all cases]. The worst correlation was found for PSV when the plaque was calcified (r = 0.238), whereas EDV showed a higher correlation (r = 0.523). Correlations of B-mode measurement were superior for plaques with smooth surface (r = 0.677), while the PSVICA/ICA ratio showed the highest correlation in stenoses with irregular (r = 0.373) or ulcerated (r = 0.382) surfaces, as well as lipid (r = 0.406), fibrous (r = 0.461), and mixed (r = 0.403; p < 0.01 in all cases) plaques. Nevertheless, differences between the mentioned correlations were not statistically significant (p > 0.05 in all cases).
UNASSIGNED: PSV, PSVICA/ICA ratio, EDV, and B-mode measurements showed comparable correlations with CTA in evaluation of carotid artery stenosis based on their correlation with CTA results. Heavy calcifications and plaque surface irregularity or ulceration negatively influenced the measurement accuracy.

Pulse wave analysis may be useful to assess fistula function. We aimed to prospectively evaluate if convenient oscillometric devices are applicable to detect flow below 500 ml/min in a real life clinical setting.
Pulse waves were recorded ambilaterally with the vicorder® device at the brachial artery in 53 patients on haemodialysis with native fistula. Primary variables consisted of the mean slope between the systolic maximum and the diacrotic notch (Slope2), the sum of the mean slopes in the four characteristic sections of pulse waves (Slope∑) and the amplitude of relative volumetric change in the measuring cuff at the upper arm (AMP). Fistula flow was measured with the use of duplex sonography using a standardized approach.
Parameter values above or below the median indicated measurement at the non-fistula side, with sensitivities/specificities of 0.79/0.79 (p < 0.001) for Slope 2, 0.64/0.64 (p = 0.003) for Slope∑ and 0.81/0.81 (p < 0.001) for AMP if measurements at the fistula and non-fistula arm were considered. ROC-analyses of parameter values measured at the fistula to detect low flow demonstrated AUCs (with CI) of 0.652 (0.437-0.866, p = 0.167) for Slope2, 0.732 (0.566-0.899, p = 0.006) for Slope∑ and 0.775 (0.56-0.991, p = 0.012) for AMP. The point with maximal youden\'s index was regarded as optimal cut-off, which corresponded to sensitivities and specificities of 0.8/0.56 for slope2, 0.86/ 0.56 for Slope∑ and 0.93/0.78 for AMP.
Functional surveillance with oscillometry is a promising clinical application to detect a low fistula flow. Among all investigated pulse wave parameters AMP revealed the highest diagnostic accuracy.

Together with colleagues from different disciplines, including cardiologists, interventional radiologists and vascular surgeons, committee members of the of the German Society of Angiology (Deutsche Gesellschaft für Angiologie [DGA]), developed a novel algorithm for the endovascular treatment of peripheral chronic total occlusive lesions (CTOs). Our aim is to improve patient and limb related outcomes, by increasing the success rate of endovascular procedures. This can be achieved by adherence to the proposed crossing algorithm, aiding the standardization of endovascular procedures. The following steps are proposed: (i) APPLY Duplex sonography and if required 3D techniques such as computed tomography or magnetic resonance angiography. This will help you to select the optimal access site. (ii) EVALUATE the CTO cap morphology and distal vessel refilling sites during diagnostic angiography, which are potential targets for a retrograde access. (iii) START with antegrade wiring strategies including guidewire (GW) and support catheter technology. Use GW escalation strategies to penetrate the proximal cap of the CTO, which may usually be fibrotic and calcified. (iv) STOP the antegrade attempt depending on patient specific parameters and the presence of retrograde options, as evaluated by pre-procedural imaging and during angiography. (v) In case of FAILURE, consider advanced bidirectional techniques and reentry devices. (vi) In case of SUCCESS, externalize the GW and treat the CTO. Manage the retrograde access at the end of the endovascular procedure. (vii) STOP the procedure if no progress can be obtained within 3 hours, in case of specific complications or when reaching maximum contrast administration based on individual patient\'s renal function. Consider radiation exposure both for patients and operators. In this manuscript we systematically follow and explain each of the steps (i)-(vi) based on practical examples from our daily routine. We strongly believe that the integration of this algorithm in the daily practice of endovascular specialists, can improve vessel and patient specific outcomes.

For the treatment of chronic venous insufficiency (CVI), various therapeutic options are available. In addition to conservative compression therapy, classical vein surgery, sclerotherapy and endoluminal therapies are increasingly being used to treat varicose veins. For a differentiated indication and correct treatment planning, a stepwise diagnosis with clinical examination and documentation of typical symptoms, dynamic vein function measurement to assess the global venous status as well as a qualitative assessment of the exact insufficient vein segments by means of color-coded duplex sonography is required. Due to the non-invasiveness of the examination and the good assessability of therapeutically relevant parameters such as anatomic conditions, diameter, and reflux of insufficient veins, color-coded duplex sonography is considered the gold standard for imaging diagnostics.
UNASSIGNED: Für die Behandlung der chronischen venösen Insuffizienz (CVI) haben sich mittlerweile verschiedene Therapieoptionen etabliert. So kommen neben der konservativen Kompressionstherapie, der klassisch operativen Entfernung und der Sklerotherapie zunehmend auch endoluminale Therapien korrespondierender Varizen zum Einsatz. Für eine differenzierte Indikationsstellung und korrekte Therapieplanung bedarf es einer stufenweisen Diagnostik mit befundorientierter klinischer Untersuchung, einer dynamischen Venenfunktionsmessung zur Beurteilung der global-venösen Gefäßsituation sowie einer qualitativen Beurteilung der exakten Insuffizienzstrecken mittels einer farbkodierten Duplexsonographie. Aufgrund der Nichtinvasivität der Untersuchung und der guten Beurteilbarkeit von therapeutisch relevanten Parametern wie anatomischem Verlauf, Durchmesser und Refluxstrecken insuffizienter Venen wird die Duplexsonographie heute als Goldstandard für die bildgebende Diagnostik angesehen.

A crossing algorithm was developed for the endovascular treatment of peripheral chronic total occlusive lesions (CTOs) to educate, guide, and appropriately influence clinical practice aiming at harmonization and standardization of endovascular procedures. The following steps are proposed: One, duplex sonography and if required computed tomography or magnetic resonance angiography for the selection of the optimal access site. Two, angiographic evaluation of the proximal/distal cap morphology, presence of collaterals at the origin of the proximal cap and at the distal vessel refilling site. In addition, evaluation of distal vessels, including their diameters and quality, and the presence of calcification or stents within the occlusion zone. Three, antegrade wiring strategies, guidewire (GW) and support catheter technology, as well as GW escalation strategies. Stop the antegrade attempt depending on clinical indication for peripheral artery disease treatment and the presence of retrograde options. Four, retrograde access site, support catheter, or sheath insertion and wiring technology from distally. Five, considering strategy change when progress cannot by achieved, using advanced bidirectional techniques and re-entry devices. Six, in case of successful GW passage from retrograde, GW externalization and treatment from antegrade. Management of the retrograde access by internal or external hemostasis at the end of the procedure. Alternatively, stop the procedure if no progress can be obtained within 3 hours or in case of specific complications. By establishing the algorithm in the daily routine of endovascular specialists, improvements in vessel- and patient-specific outcomes are anticipated. In addition, future research, and continuous collaboration between experts is warranted.

Ultrasonographic parameters such as the common carotid artery (CCA) pulsatility index (PI) and CCA intima-media thickness (IMT) have been associated with an increased mortality and risk of recurrent stroke, respectively. We hypothesized that these ultrasonographic parameters may be useful for monitoring diabetic patients after an acute stroke. We analysed retrospective data of consecutive acute ischaemic stroke patients from the ASTRAL registry who underwent pre-cerebral ultrasonographic evaluation within 7 days of symptom onset. We compared clinical, demographic, radiological and ultrasonographic parameters in diabetic versus non-diabetic patients (univariable and multivariable analyses) and the association of these parameters with CCA PI and CCA IMT. We analysed 1507 carotid duplex ultrasound examinations from patients with a median age of 74 years. Cardiovascular co-morbidities, including hypertension, hypercholesterolemia, obstructive sleep apnoea syndrome, higher body-mass index (BMI) and peripheral artery disease, were associated with diabetes mellitus (DM). Diabetics were more often under antiplatelet therapy and had atrial fibrillation at admission. Diabetic patients showed an increased CCA PI and IMT in line with more atherosclerotic changes on acute CTA compared to non-diabetic patients. Taking IMT as the dependent variable in a second analysis, DM, higher age, hypertension, smoking and CCA PI were associated with higher IMT. Taking CCA PI as the dependent variable in a third analysis, DM, higher age and higher NIHSS at admission were associated with higher CCA PI values. Increased IMT was also associated with higher PI. We show that CCA PI and IMT are higher in diabetic patients in the first week after an initial stroke.

UNASSIGNED: Patients with acute limb ischaemia (ALI) present with acute symptoms, requiring prompt diagnosis and expedited treatment to preserve the viability of the affected ischaemic tissue.
UNASSIGNED: We present an 83-year-old female patient with upper ALI due to thrombotic occlusion of the left brachial artery. Concomitantly, the patient had a first diagnosis of atrial fibrillation and was not on treatment with oral anticoagulation. Transfemoral thrombectomy using a 6F Rotarex® catheter resulted in removal of the thrombus from the brachial artery. However, significant amounts of debris embolized distally, causing occlusion of both the radial and ulnar arteries. The debris was successfully removed after puncture of the distal radial artery and retrograde thrombus aspiration using a 5F Envoy catheter. This manoeuver led to flow restoration in both the radial and ulnar arteries and to complete resolution of ischaemic symptoms of the patient.
UNASSIGNED: Interventionists may consider distal radial puncture not only as an access site for coronary angiography but also as an option for the endovascular management of ALI in cases of cardiac embolism, as described herein or in cases of thrombotic complications during routine catheterization and percutaneous coronary intervention. Herein, we describe the case of an 83-year-old patient, who presented with acute upper limb ischaemia. Due to embolization of thrombotic debris during Rotarex® catheter thrombectomy, flow further diminished in the ulnar and radial arteries. The last hope for successful interventional treatment was thrombectomy from distally after retrograde puncture of the distal radial artery. This unique manoeuver led to flow restoration and complete recovery of the patient without the need for open surgery.

Transient global amnesia (TGA) is a self-limiting neurological condition that temporarily affects patients\' ability to access and store memories. So far, its etiology is unknown; however, ischemic origin has been discussed in the past. We present the case of a 61-year-old female with clinical appearance of TGA. MRI and duplex scan revealed punctiform and patchy ischemic lesions in both temporal lobes and right vertebral artery dissection, suggesting basilar artery embolism as the underlying cause. Our case report shows that TGA can be a symptom of ischemic lesions in the hippocampus and patients with presentation of additional focal neurologic symptoms or atypical distribution or appearance of the diffusion-weighted image (multiple/patchy) lesions should get ischemic stroke diagnosis and treatment.