Impact of Internal Carotid Stenosis Treatment on Cerebral Blood Flow Volume: A Comparative Study between Preoperative and Postoperative Values.

BACKGROUND Among patients with ICA stenosis, there are some cases with elevated, undisrupted, and diminished cerebral blood flow (CBF). The aim of this study was to assess the influence of ICA stenosis treatment on postoperative CBF changes in relation to preoperative CBF values. MATERIAL AND METHODS We qualified 58 patients ≥65 years old (28 males, 30 females, mean age 71.02±6.34 years) for surgical intervention due to symptomatic ≥70% ICA stenosis. In all patients, a flow volume in all extracranial arteries (internal carotid [ICA], external carotid [ECA], and vertebral arteries [VA]) was measured preoperatively and 2-3 days following the surgery. The CBF values were compared with the ones established for a healthy population of the same age. RESULTS Preoperatively, there were 3 subgroups of patients, comparing to healthy population: with elevated CBF - "significant compensation," with undisrupted CBF - "mild compensation," and with diminished CBF - "no compensation." Postoperatively, a significant CBF increase was observed in patients with preoperative "no" and "mild compensation" - 277.18±154.26 ml/min (P=0.0000001) and 221.56±98.8 ml/min (P=0.0000001). In a "significant compensation" group, there was no flow increase observed (CBF change of 2.57±58.5 ml/min, P=0.954) - a redistribution of flow was observed. CONCLUSIONS In patients with lower preoperative CBF values, surgical treatment caused a significant increase in global cerebral inflow, which was more prominent in patients with the lowest preoperative CBF. In patients with high preoperative CBF, surgical treatment resulted in a flow redistribution, but did not cause a CBF increase. Volumetric flow assessment in DUS can predict hemodynamic benefit from surgery in terms of CBF increase.

Volumetric Flow Assessment in Extracranial Arteries in Patients with 70-99% Internal Carotid Artery Stenosis.

Background: Cerebral blood flow (CBF) can be related to the risk of occurrence of neurological symptoms. Well-developed collateral circulation is a good prognostic factor in patients with cerebrovascular disease. Understanding the mechanisms of collateral circulation may be important in the diagnosis, treatment, and monitoring in this group of patients. The aim of this study covered the assessment of CBF in patients with 70−99% Internal carotid artery (ICA) stenosis, focusing on the circulation pathways and flow volume in extracranial arteries. Materials and methods: 53 patients with 70−99% ICA stenosis (mean age 73.4 ± 7 years old; 17 female, mean age 73.9 ± 7.5 years old; 36 male, mean age 73.2 ± 6.8 years old) were included in the study. In all patients a Doppler ultrasound (DUS) examination, measuring blood flow volume in the internal carotid artery (ICA), external carotid artery (ECA), and vertebral artery (VA), was performed. The cerebral blood flow (CBF) was compared to the previously reported CBF values in the healthy population > 65 years old. Results: Among the study groups three subgroups with flow differences were identified: patients with elevated CBF (significant volumetric flow compensation­26/53, 49%), patients with CBF similar to (mild compensation­17/53, 32%), and patients with CBF lower than (no compensation­10/53, 19%) the healthy, equally aged population. The percentage of patients with significant volumetric flow compensation was the highest in age groups 65−69 years old (62.5%) and >80 years old (60%). In the oldest age group (>80 years old) no patients without flow compensation (0%) were observed. The level of compensation depends on the number of the arteries with compensatory increased flow. In patients with significant volumetric flow compensation, the compensatory increased flow was observed, on average, in 3.31 arteries, in the mild compensation group­in 2.18 arteries, and in the no compensation group only in 1 artery. ICA plays the most important role in the volumetric flow compensation­the increase in the flow volume, in comparison to the reference values, was between 116.7 mL/min and 251.9 mL/min (in the ECA 57.6 mL/min−110.4 mL/min; in the VA 73.9 mL/min−104.9 mL/min). The relative flow increase was highest in the VA: 215−246%, then in the ECA: 163−206%, and finally in the ICA: 148.6−192%. The increased flow was most commonly observed in the VA­57 arteries, in second place in the ECA­42 arteries, and ICA­31 arteries. In patients with unilateral ICA stenosis, the volumetric flow increase was stated more frequently in the ipsilateral ECAs then in the contralateral ones (23 vs. 14). In the VA the opposite tendency was observed (29 contralateral vs. 23 ipsilateral). The ability of volumetric flow compensation decreased significantly with increasing age. Conclusions: Understanding the mechanisms of collateral circulation and their assessment in Doppler ultrasonography may provide a novel and easily accessible tool of identifying and monitoring patients with cerebrovascular disease.

Intracranial Flow Volume Estimation in Patients with Internal Carotid Artery Occlusion.

(1) Background: Carotid artery occlusion (CAO) in population studies has a reported prevalence of about 6 per 100,000 people; however, the data may be underestimated. CAO carries a significant risk of stroke. Up to 15% of large artery infractions may be secondary to the CAO, and in 27−38% of patients, ischaemic stroke is a first presentation of the disease. The presence of sufficient and well-developed collateral circulation has a protective influence, being a good prognostic factor in patients with carotid artery disease, both chronic and acute. Understanding the mechanisms and role of collateral circulation may be very important in the risk stratification of such patients. (2) Materials and Methods: This study included 46 patients (mean age: 70.5 ± 6 years old; 15 female, mean age 68.5 ± 3.8 years old and 31 male, mean age 71.5 ± 6.7 years old) with unilateral or bilateral ICA occlusion. In all patients, a Doppler ultrasound (DUS) examination, measuring blood flow volume in the internal carotid artery (ICA), external carotid artery (ECA), and vertebral artery (VA), was performed. The cerebral blood flow (CBF) was compared to the previously reported CBF values in the healthy population >65 years old. (3) Results: In comparison with CBF values in the healthy population, three subgroups with CBF changes were identified among patients with ICA occlusion: patients with significant volumetric flow compensation (CBF higher than average + standard deviation for healthy population of the same age), patients with flow similar to the healthy population (average ± standard deviation), and patients without compensation (CBF lower than the average-standard deviation for healthy population). The percentage of patients with significant volumetric flow compensation tend to rise with increasing age, while a simultaneous decline was observed in the group without compensation. The percentage of patients with flow similar to the healthy population remained relatively unchanged. ICA played the most important role in volumetric flow compensation in patients with CAO; however, the relative increase in flow in the ICA was smaller than that in the ECA and VA. Compensatory increased flow was observed in about 50% of all patent extracranial arteries and was more frequently observed in ipsilateral vessels than in contralateral ones, in both the ECA and the VA. In patients with CAO, there was no decrease in CBF, ICA, ECA, and VA flow volume with increasing age. (4) Conclusions: Volumetric flow compensation may play an important predictive role in patients with CAO.

Volumetric Flow Assessment in Doppler Ultrasonography in Risk Stratification of Patients with Internal Carotid Stenosis and Occlusion.

(1) Background: Alterations of blood flow volume in extracranial arteries may be related to the risk of occurrence of neurological symptoms. The aim of this study was the estimation of cerebral blood flow (CBF) in Doppler ultrasonography, as well as comparison of the flow volume in asymptomatic patients over 65 years old with ≥50%, and symptomatic patients with ≥70% internal carotid artery (ICA) stenosis, in order to assess whether the changes in the CBF correlates with the presence of neurological symptoms. (2) Methods: 308 patients over 65 years old were included in the retrospective cohort observational study: 154 asymptomatic with ≥50% ICA stenosis, 123 healthy volunteers, and 31 symptomatic referred for surgical treatment. The study group was split according to ICA stenosis (50-69%, 70-99% and occlusion). In all patients an extensive Doppler ultrasound examination with measurements of flow volume in common, internal, external carotid (ECA) and vertebral arteries (VA) was performed. (3) Results: Among asymptomatic (A) and symptomatic (S) patients with carotid stenosis 3 subgroups were identified: 57/154-37% (A) and 8/31-25.5% (S)-with significantly increased flow volume (CBF higher than reference range: average CBF + std. dev in the group of healthy volunteers), 67/154-43.5% (A) and 12/31-39% (S)-with similar to reference group flow volume (CBF within range average ± std.dev), and 30/154-19.5% (A) and 11/31-35.5% (S)-with decreased flow volume in extracranial arteries (flow lower than average-std.dev. in healthy volunteers). In symptomatic patients the percentage of patients with significant compensatory increased flow tends to raise with the severity of the stenosis, while simultaneous decline of number of patients with mild compensation (unchanged total CBF) is observed. The percentage of patients without compensation remains unchanged. In the group referred for surgical treatment (symptomatic, ≥70% ICA stenosis) the percentage of patients with flow compensation is twice as low as in the asymptomatic ones with similar degree of the ICA stenosis (8/31-25.8% vs. 26/53-49%, p = 0.04). Compensatory elevated flow was observed most frequently in ECA. (4) Conclusions: The presence of significant volumetric flow compensation has protective influence on developing ischaemic symptoms, including TIA or stroke. The assessment of cerebral inflow in Doppler ultrasonography may provide novel and easily accessible tool of identifying patients prone to cerebral ischaemia. The multivessel character of compensation with enhanced role of ECA justifies the importance of including this artery in the estimation of CBF.

Multiple occlusions in extracranial arteries in patients with aortic arch syndrome: is minimally invasive treatment still possible? Technical aspects of the treatment based on our own experience and a review of the literature.

Takayasu arteritis is a large vessel vasculitis of granulomatous nature and unknown aetiology affecting predominantly the aorta and its major branches, which may lead to ischaemic symptoms of many organs including the central nervous system. To decrease the risk of neurological complications and improve the quality of life, an arterial revascularisation may be necessary. The treatment options include pharmacotherapy as well as both open surgical and endovascular procedures, which has to be carefully chosen to obtain clinical success. There is an ongoing debate on the advantages, possibilities, and indications for implementing endovascular and open surgical methods, especially in high-risk patients. In this article we present our own experience in the treatment of an unusually complex and high-risk patient with multiple occlusion of supra-aortic branches, focusing on the technical aspects of the procedures and the decision-making process, as well as to confront with contemporary medical knowledge.

Volumetric Flow Changes in Extracranial Arteries in a Symptomatic Patient with Significant Bilateral Carotid Artery Stenosis: A Case Study and Literature Review.

BACKGROUND Hemodynamically significant carotid artery stenoses are rarely diagnosed in people under 60 years of age, being mainly secondary to other concomitant diseases. Cerebral blood flow volume, which correlates with cerebrovascular reserve and susceptibility of ischemic symptoms occurrence, may aid in the diagnosis and monitoring of patients with carotid artery disease. In this report we present the case of a patient with significant bilateral carotid stenosis, focusing on the ultrasonographically measured changes in blood flow volume in extracranial arteries following surgeries. CASE REPORT A 41-year-old man with a positive history of transient ischemic attack (TIA)  was referred to our department after being diagnosed with significant 80% to 85% right internal carotid artery (ICA) and 60% left ICA stenosis. After successful carotid endarterectomy, the flow volume in extracranial arteries significantly increased (from 755 mL/min to 1053 mL/min) due to an increase of flow volume in the right ICA. With the progression of left ICA stenosis, cerebral blood flow decreased, and the patient presented with a second TIA. Following the successful treatment of the left ICA stenosis (consisting of carotid endarterectomy and stent implantation because neointimal hyperplasia resulted in significant, recurrent 80% left ICA stenosis), an increase in flow volume was observed. CONCLUSIONS Assessment of the blood flow volume in extracranial arteries may be an effective tool in monitoring patients with carotid stenoses. Due to the lack of literature on this topic, further research on cerebral blood flow volume in surgical and non-surgical patients is needed to understand this phenomenon.

Combined Treatment of Multiple Splanchnic Artery Aneurysms Secondary to Median Arcuate Ligament Syndrome: A Case Study and Review of the Literature.

BACKGROUND Median arcuate ligament syndrome (MALS) is a rare and often misdiagnosed condition affecting about 0.4% of the population, typically ages 20-50 years old, and more frequently females. Caused by the compression of the celiac artery and adjacent nervous structures by the median arcuate ligament, it is typically manifested by postprandial abdominal pain, nausea or vomiting, and loss of weight. This condition also results in compensatory increased blood flow in peripancreatic arcades, facilitating formation of true aneurysms of the visceral vessels. CASE REPORT A 45-year-old woman with hypertension and left inferior renal pole cysts was referred to our department due to chronic, recurrent postprandial abdominal pains, nausea, and weight loss of approximately 15 kg in 1 year. A computed tomography (CT) scan demonstrated complete occlusion of the celiac trunk, significant stenosis of the superior mesenteric artery, and multiple aneurysms up to 17 mm in collateral circulatory vessels. Surgical decompression of the median arcuate ligament was performed and venous bypass was implanted between the aorta and the common hepatic artery, resulting in restoration of proper blood in the visceral circulation. Subsequently, 2 endovascular embolizations of visceral aneurysms were successfully performed. In the 48-month follow-up period, there was resolution of symptoms and no aneurysm formation was observed. CONCLUSIONS Endovascular methods should be the treatment of choice in patients with splanchnic artery aneurysms. However, in patients with multiple aneurysms secondary to MALS, arterial reconstruction may be considered prior to performing an endovascular procedure to restore physiological blood flow in the visceral circulation.

Volumetric Carotid Flow Characteristics in Doppler Ultrasonography in Healthy Population Over 65 Years Old.

BACKGROUND: Carotid flow velocity criteria are well established, with age being a factor influencing measurements. However, there are no volumetric standards for the flow in extracranial arteries. The aim of the study was related to volumetric flow assessment of extracranial arteries in a healthy population >65 years old. METHODS: Doppler volumetric measurements of internal carotid (ICA), external carotid (ECA) and vertebral arteries (VA) were performed in 123 healthy volunteers >65 years old and compared with 56 healthy volunteers <65 years old. RESULTS: The continuous decline in cerebral blood flow (CBF) volume was observed (p < 0.00001). Volumetric reference values were established in study groups: 1., 65-69 years: 898.5 ± 119.1; 2., 70-74 years: 838.5 ± 148.9; 3., 75-79 years: 805.1 ± 99.3; 4., >80 years: 685.7 ± 112.3 (mL/min). Significant differences were observed between groups: 1 and 3.4, as well as 3 and 4 (p = 0.0295, < 0.000001, 0.00446 respectively). CBF volume decreases gradually with age: 28-64 years-6.2 mL/year (p = 0.0019), 65-75 years-11.4 mL/year (p = 0.0121) and >75 years-14.3 mL/year (p = 0.0074). This is a consequence of flow volume decline in ICA (p = 0.00001) and to lesser extent ECA (p = 0.0011). The decrease of peak systolic (p = 0.002) and end diastolic (p = < 0.00001) velocities in ICA and peak systolic velocity in ECA (p = 0.0017) were observed. CONCLUSIONS: CBF decreases with ageing. Volumetric assessment of CBF may play an important additional role in diagnostics of patients with carotid stenosis. Doppler assessment of cerebral flow volume may create an interesting tool for identifying patients with diminished cerebrovascular reserve and higher risk of ischemic symptoms occurrence.

The importance of blood flow volume in the brain-supplying arteries for the clinical management - the impact of collateral circulation.

AIM: An assessment of increased compensatory blood flow in the brain-supplying arteries in patients with significant carotid artery stenosis. MATERIALS AND METHODS: Doppler ultrasound was performed in 218 patients over 60 years of age to evaluate both the degree of brain-supplying artery stenosis as well as the blood flow volume balance in all vessels supplying the brain: the internal carotid artery, the external carotid artery and the vertebral artery. The control group included 94 patients with no stenosis in the extracranial segments and no neurological manifestations, in whom blood flow values were calculated (the internal carotid artery - 290 mL/min, the external carotid artery - 125 mL/min, the vertebral artery - 80 mL/min); the total mean blood flow in the brain-supplying arteries was 985 mL/min. A 33% increase in blood flow was considered compensatory. In addition to the control group, 30 patients with asymptomatic stenosis of less than 50% and 12 patients after endarterectomy with mean blood flow of 920 mL/min and 960 mL/min, as well as two groups of particular interest to us, i.e. 38 patients with no compensatory blood flow increase despite significant stenosis (>50%) with mean blood flow of 844 mL/min and 44 patients with similar stenosis and with compensatory blood flow increase up to 1174 mL/min were included in the analysis. RESULTS: Comparison of the two groups showed several significant differences: increased blood flow (118% vs. 86% of the norm) in patients with compensated stenosis, an increased number of asymptomatic patients (70% vs. 37%) and a threefold increase in the number of patients with occlusions (15 : 5) in the group of patients with increased blood supply to the brain. CONCLUSIONS: All potential blood-supplying vessels, including the external carotid artery, are involved in brain tissue perfusion in some of the patients with significant stenosis. Determining the degree of compensation may have an important impact on the indications for surgical treatment, which will make a valuable contribution to the current criteria (asymptomatic/symptomatic patients).

Recommendations for ultrasonographic assessment of renal arteries.

The present clinical practice recommendations are addressed to physicians of all specialties, who perform Doppler ultrasound examinations of the kidneys on a daily basis, and in particular to specialists in radiology and imaging diagnostics. The recommendations were based on the Ultrasonography Standards of the Polish Ultrasound Society and current scientific reports consistent with Evidence Based Medicine. The paper discusses patient preparation protocol, examinat ion technique with particular emphasis on patient's position allowing to obtain proper Doppler angle of insonation, as well as diagnostic limitations of the technique. Normal blood flow parameters as well as those indicating hemodynamically significant stenosis are also presented. Although the 2013-2014 American guidelines for renal artery duplex sonography (AIUM Practice Parameter for the Performance of Native Renal Artery Duplex Sonography and AIUM Practice Guideline for the Performance of an Ultrasound Examination of Solid-Organ Transplants), which were the basis for many national recommendations, have not been significantly updated to date, a large body of scientific research indicates the need for revision of current Doppler ultrasound standards and parameters, particularly for patients receiving endovascular treatment due to renovascular hypertension. Therefore, the paper refers to the current issue of ultrasound scan interpretation in patients receiving endovascular stenting, after transplantation of kidney, as well as in pediatric patients.The present clinical practice recommendations are addressed to physicians of all specialties, who perform Doppler ultrasound examinations of the kidneys on a daily basis, and in particular to specialists in radiology and imaging diagnostics. The recommendations were based on the Ultrasonography Standards of the Polish Ultrasound Society and current scientific reports consistent with Evidence Based Medicine. The paper discusses patient preparation protocol, examinat ion technique with particular emphasis on patient's position allowing to obtain proper Doppler angle of insonation, as well as diagnostic limitations of the technique. Normal blood flow parameters as well as those indicating hemodynamically significant stenosis are also presented. Although the 2013­2014 American guidelines for renal artery duplex sonography (AIUM Practice Parameter for the Performance of Native Renal Artery Duplex Sonography and AIUM Practice Guideline for the Performance of an Ultrasound Examination of Solid-Organ Transplants), which were the basis for many national recommendations, have not been significantly updated to date, a large body of scientific research indicates the need for revision of current Doppler ultrasound standards and parameters, particularly for patients receiving endovascular treatment due to renovascular hypertension. Therefore, the paper refers to the current issue of ultrasound scan interpretation in patients receiving endovascular stenting, after transplantation of kidney, as well as in pediatric patients.

Standards of the Polish Ultrasound Society. Ultrasound examination of the portal system and hepatic vessels.

Increased incidence of liver diseases, the development of liver surgery and other invasive methods for managing portal hypertension, plus an increasing number of liver transplant procedures pose more and more new challenges for ultrasonography. Ultrasonography, being an effective and clinically verified modality, has been used for several decades for diagnosing diseases of the liver, its vessels and portal hypertension. It is used for both initial and specialist diagnosis (performed in reference centers). The diagnostic value of ultrasonography largely depends on the knowledge of anatomy, physiology, pathophysiology and clinical aspects as well as on the mastering of the scanning technique. In the hands of an experienced physician, it is an accurate and highly effective diagnostic tool; it is of little use otherwise. The paper presents elements of anatomy, physiology and pathophysiology which make the portal system exceptional and the knowledge of which is crucial and indispensable for a correct examination and, above all, for the correct interpretation of results. The authors also present requirements regarding the equipment. Moreover, various technical aspects of the examination are presented and the normal morphological picture and hemodynamic parameters of healthy individuals are described. The authors discuss the most common clinical situations and rare cases during ultrasound examinations. The paper is based on the experience of the author who works in the largest center of liver diseases in Poland, and on the current literature.

Standards of the Polish Ultrasound Society - update. Ultrasound examination of the visceral arteries.

Ultrasound examination is a valuable method in diagnosing visceral vasoconstriction of atherosclerotic origin, as well as constriction related to the compression of the celiac trunk. Given the standard stenosis recognition criteria of >70%, the increase in peak systolic velocity (PSV) over 200 cm/s in the celiac trunk; of PSV > 275 cm/s in the superior mesenteric artery, and of PSV > 250 cm/s in the inferior mesenteric artery, the likelihood of correct diagnosis is above 90%. In the case of stenosis due to compression of the celiac trunk by median arcuate ligament of the diaphragm, a valuable addition to the regular examination procedure is to normalize the flow velocity in the vessel, i.e. the reduction in peak systolic velocity levels below 200 cm/s, and in end-diastolic velocity (EDV) levels below 55 cm/s during deep inspiration. In the case of celiac trunk stenosis exceeding 70-80%, additional information on the level of collateral circulation can be obtained by measuring the flow in the hepatic and splenic arteries - assessing the flow velocity, resistance, and pulsatility indices (which fall below 0.65 and below 1.0 in cases of stenosis of the celiac trunk with a reduced capacity of collateral circulation), as well as assessing the changes in these parameters during normal respiration and during inspiration. This paper discusses in detail the examination methods for the celiac trunk and mesenteric arteries, as well as additional procedures used to confirm the diagnosis and pathologies affecting visceral blood flow velocity, i.e.: cirrhosis and hypersplenism. The publication is an update of the Polish Ultrasound Society guidelines published in 2011.

Standards of the Polish Ultrasound Society - update. Examination of extracranial carotid and vertebral arteries.

The role of a standard is to describe examination techniques, recommended norms as well as principles necessary to obtain results and draw appropriate conclusions, rather than a description of pathologies. The paper presents a technique for carotid artery examination as well as currently recommended standards. According to San Francisco Consensus from 2003, a significant stenosis of 70% may be detected when systolic velocity in the internal carotid artery stenosis is >230 cm/s, and the diastolic velocity is >100 cm/s. The common carotid artery velocity is also taken into account. Hemodynamic evaluation is therefore the primary method for the assessment of the degree of internal carotid artery stenosis. It is important that the examination is performed at an insonation angle of 60° as measurements at higher angles result in an exponential increase in measurement error. Also, an extended version of standards involving measurements performed behind stenosis, which are used in some clinics, is included in the paper. The paper further presents guidelines for the description of the identified pathologies, which ensure that the findings prove unambiguous for clinicians, especially when stenosis eligible for surgical intervention is detected. Morphological measurement of stenosis (according to NASCET criteria) is only of supplementary character (confirming morphological grounds for the increase of velocity) and has no critical importance, especially due to high measurement divergence. Description of atherosclerotic plaques, especially hypoechoic ones, which are considered potentially unstable and may lead to a raised risk of stroke, is a very important element of examination. The paper is based on Standards of the Polish Ultrasound Society and updated based on the latest literature reports.

Standards of the Polish Ultrasound Society - update. Ultrasound examination of the aorta and arteries of the lower extremities.

A Doppler ultrasound examination has an advantage over other vessel imaging methods as it can be carried out by the patient's bedside and allows to make a diagnosis without exposing the patient to the inconveniency of transportation or an X-ray scan. The purpose of testing the lower extremities and the aorta is to objectively confirm a preliminary clinical diagnosis, localize lesions responsible for the symptoms of the disease, determine their severity and nature (e.g., if they are calcifications or soft lesions), and finally evaluate the hemodynamic criteria. In assessment of the aorta attention is paid not only to aortic diameter measurements, but also to the vascular lumen (dissections with the formation of two flow channels, detachments, balloting of atherosclerotic plaques, etc.) and the presence of atherosclerotic plaques with influx into them (PAU - penetrating ulcer in the plaque or lesions surrounding the aorta, such as retroperitoneal fibrosis or mycotic aneurysm). A correct diagnosis of an abdominal aortic aneurysm requires repeated measurements of the abdominal aorta diameter, and in particular its transverse dimension. When assessing the degree of peripheral arterial stenosis on the basis of hemodynamic parameters, degree of morphological stenosis must be taken into consideration. Collateral circulation may reduce the flow through the main vessel, and thus, the achieved systolic velocities are lower and may understate the degree of the assessed stenosis. Calf vessels are difficult to detect, which results both from the thickness of the muscle and the presence of calcifications. This article has been prepared on the basis of Standards of the Polish Ultrasound Society (2011) and updated on the basis of the latest reports from relevant literature.