Value of ultrasound in the diagnosis of aneurysms of the extracranial internal carotid arteries

Aneurysms of the extracranial carotid arteries are a rare abnormalitiy and may represent a diagnostic challenge in examination of the patients. B-flow is a new digital vascular ultrasound technique and is an especially reliable method in the diagnosis of the extracranial portion of the internal carotid arteries as it shows less flow artifacts than color-coded Doppler sonography (CCDS) and power Doppler (PD). This review compares color-coded Doppler sonography, power Doppler and B-flow findings in extracranial ICA and CA aneurysm to emphasize the usefulness of B-flow in this clinical condition.     

Vascularization of liver tumors - preliminary results with Coded Harmonic Angio (CHA), phase inversion imaging, 3D power Doppler and contrast medium-enhanced B-flow with second generation contrast agent (Optison)

PURPOSE: To investigate the dynamic value of contrast medium-enhanced ultrasonography with Optison for appraisal of the vascularization of hepatic tumors using harmonic imaging, 3D-/power Doppler and B-flow. MATERIALS/METHODS: 60 patients with a mean age of 56 years (range 35-76 years) with 93 liver tumors, including histopathologically proven hepatocellular carcinoma (HCC) [15 cases with 20 lesions], liver metastases of colorectal tumors [17 cases with 33 lesions], metastases of breast cancer [10 cases with 21 lesions] and hemangiomas [10 cases with 19 lesions] were prospectively investigated by means of multislice CT as well as native and contrast medium-enhanced ultrasound using a multifrequency transducer (2.5-4 MHz, Logig 9, GE). B scan was performed with additional color and power Doppler, followed by a bolus injection of 0.5 ml Optison. Tumor vascularization was evaluated with coded harmonic angio (CHA), pulse inversion imaging with power Doppler, 3D power Doppler and in the late phase (>5 min) with B-flow. In 15 cases with HCC, i.a. DSA was performed in addition. The results were also correlated with MRT and histological findings. RESULTS: Compared to spiral-CT/MRT, only 72/93 (77%) of the lesions could be detected in the B scan, 75/93 (81%) with CHA and 93/93 (100%) in the pulse inversion mode. Tumor vascularization was detectable in 43/93 (46%) of lesions with native power Doppler, in 75/93 (81%) of lesions after administering contrast medium in the CHA mode, in 81/93 (87%) of lesions in the pulse inversion mode with power Doppler and in 77/93 (83%) of lesions with contrast-enhanced B-flow. Early arterial and capillary perfusion was best detected with CHA, particularly in 20/20 (100%) of the HCC lesions, allowing a 3D reconstruction. 3D power Doppler was especially useful in investigating the tumor margins. Up to 20 min after contrast medium injection, B-flow was capable of detecting increased metastatic tumor vascularization in 42/54 (78%) of cases and intratumoral perfusion in 17/20 (85%) of HCC cases. All 19 hemangiomas were correctly classified by phase inversion imaging. CONCLUSIONS: Contrast medium-enhanced ultrasound investigation of liver tumors with Optison allowed reliable detection of tumor foci and, in most cases, appraisal of tumor vascularization. The time available for evaluation of tumor margin vascularization was substantially longer in B-flow.     

Value of high resolution ultrasound and contrast enhanced US pulse inversion imaging for the evaluation of the vascular integrity of free-flap grafts

OBJECTIVE: The aim of this study was to evaluate the clinical value of color coded Doppler sonography (CCDS) and contrast-enhanced harmonic imaging (CHI) for ultrasound (US) monitoring the integrity of free-flap vascular grafts. Patency of microvascular anastomoses and perfusion as well as microcirculation of the transplanted tissue were analysed. PATIENTS AND METHODS: Fifteen free parascapular flap grafts performed over a period of three years by a single surgeon were examined with CCDS and CHI. The patients (12 male, 3 female) ranged in age from 16 to 60 years (average age 40+/-12). The follow-up period ranged from two weeks to 2.5 years. CCDS were performed with a multifrequency linear transducer (5-10 MHz, Logiq 9, GE) with 3D flow detection. For detection and characterization, B scan of the flap tissue was compared to tissue harmonic imaging (THI) and Cross Beam with Speckle Reduction Imaging (SRI). US Pulse Inversion Harmonic Imaging (PIHI) after bolus injection of 2.5 ml Sonovue was used for contrast enhancement. RESULTS: Border and tissue structure of the flaps could be detected best in all 15/15 cases using Cross Beam Technology with SRI and THI. Correlations were found for flow parameters of the common femoral artery, popliteal artery and lower leg artery to the anastomotic vessels. 3D imaging with CCDS facilitated flow detection of elongated and small anastomotic vessels in 4/15 cases. Contrast-enhanced US with PIHI allowed dynamic flow detection of the microcirculation of the transplanted tissue over a depth of up to 3 cm with quantitative perfusion curves of the tissue microcirculation. Reduced US contrast enhancement with modified perfusion curves was seen in 2/15 cases with low anastomic flow in CCDS. CONCLUSION: Assessment of microvascular perfusion with contrast-enhanced ultrasound can provide valuable information on free flap viability. Contrast-enhanced US enables dynamic and quantitative flow detection of free flap tissue.     

彩色多普勒超声对双侧颈内动脉狭窄血流速度高估的研究

目的探讨彩色多普勒超声（CDU）与经颅多普勒超声（TCD）联合评价双侧颈内动脉狭窄后一侧颈内动脉（ICA）狭窄率为70％～99％或闭塞时,对另一侧的ICA（狭窄率为50％～69％）血流动力学的影响。方法连续纳入2005年6月_2011年6月由彩色多普勒血流显像（CDFI）与TCD联合筛查、DSA证实的双侧ICA狭窄（一侧颈内动脉狭窄率为70％～99％或闭塞,另一侧为50％-69％）的患者102例作为研究组（A组）,同期选择单侧ICA狭窄率为50％～69％、对侧正常的患者89例为对照组（B组）。比较两组患者中狭窄率为50％～69％狭窄侧的ICA和大脑前动脉（ACA）的收缩期峰值流速（PSV）、舒张期末流速（EDV）、血管阻力指数（RI）和血管搏动指数（PI）的差异。并根据TCD和DSA检测的结果,将A组分为前交通支开放组（A1组54例）与未开放组（A2组48例）,进一步比较两组间中狭窄率为50％～69％狭窄侧ICA、ACA血流动力学参数的差异及血流动力学变化的相关性。结果①A组患者中狭窄率为50％～69％侧ICA、ACA的PSV、EDV高于B组（均P〈0．05）,RI及PI值较B组降低（P=0．001,P=0．000）。②A1组中狭窄率为50％～69％狭窄侧ICA、ACA的PSV、EDV均高于A2组（均P〈0．01）,但A1组ICA的RI值及ACA的PI均低于A2组（P=0．000,P=0．000）,差异均有统计学意义。@ICA的PSV、EDV与ACA的呈正相关（r=0．327、r=0．422,P=0．007、P=0．000）。结论当一侧ICA狭窄率为70％～99％,狭窄率为50％～69％狭窄侧ICA的流速测值明显高于实际病变程度的诊断标准。前交通支开放是双侧ICA狭窄的血流动力学变化的基础,双侧ICA狭窄程度的判断应结合颅内外血流动力学变化进行综合评价。     

Comparison of auscultation, continuous wave Doppler imaging, intravenous digital subtraction angiography and conventional angiography in diagnosis of carotid artery disease

The reliability of auscultation, continuous wave (CW) Doppler imaging, and intravenous digital subtraction angiography (IV DSA) in the assessment of carotid artery disease has been evaluated in comparison with conventional angiography in 30 patients. With auscultation, specificity and sensitivity for internal carotid artery (ICA) stenosis of 50% or more were 81% and 67% respectively. CW Doppler imaging detected ICA stenosis of 50% or more with a sensitivity of 83% and a specificity of 92% and ICA occlusion with a sensitivity of 60%. The specificity of IV DSA was 95% and the sensitivity for ICA stenosis of 50% or more and ICA occlusion were 75% and 100% respectively. Combining CW Doppler and IV DSA findings raised sensitivity for ICA stenosis of 50% or more and ICA occlusion to 89% and 100% respectively and specificity to 95%. The combination of CW Doppler and IV DSA is a safe and accurate test battery in the detection and categorization of carotid disease.     

The impact of different spectral Doppler criteria on the proportion of high-grade internal carotid artery stenosis in patients undergoing duplex scanning

AIM: To investigate the impact of different spectral Doppler criteria on the proportion of high-grade ICA stenosis in patients undergoing carotid artery duplex scanning. MATERIAL AND METHODS: Duplex scans of 4,548 internal carotid arteries (ICA) in 2,349 patients were retrospectively analyzed. The following different criteria were applied for each scan for definition of ICA stenosis > or = 70%: Criteria I=ICA peak systolic velocity (PSV) > 130 cm/sec and ICA end-diastolic (EDV) > 100 cm/sec, Criteria II=PSV ICA/common carotid artery (CCA) ratio > 4, Criteria III=ICA PSV > or = 230 cm/sec, Criteria IV=ICA PSV > 230 cm/sec and/or ICA EDV > or = 100 cm/sec and/or PSV ICA/CCA ratio > or = 3.2. RESULTS: The frequency of detecting a > or = 70% ICA stenosis with criteria I, II, III, and IV were 5.5%, 6.8%, 8.4%, and 9.6%, respectively (p < 0.05). CONCLUSION: The use of various duplex criteria significantly affected the number of scans receiving a diagnosis of ICA stenosis of > or = 70%.     

Grading of internal carotid artery stenosis: comparative analysis of different flow velocity criteria and multidetector computed tomographic angiography.

PURPOSE: To evaluate multidetector computed tomographic angiography (CTA) versus published color Doppler sonography (CDS) velocity criteria in the grading of internal carotid artery (ICA) stenosis. METHODS: Sixty-eight consecutive patients (50 men; mean age 70.2 +/- 8.1 years, range 51- 85) with known ICA stenosis and complete CTA and CDS data for 127 carotid arteries were enrolled in this retrospective analysis. The degree of stenosis was determined using CDS velocities according to 5 published sets of criteria, as well as the criteria used at the authors' institution. These outcomes were then correlated using kappa-statistics with the results of multidetector CTA according to NASCET. RESULTS: The best overall agreement was achieved applying the criteria sets of Hwang (kappa = 0.70) and AbuRahma (kappa = 0.68). All 5 occlusions were correctly identified with both modalities. CTA detected 73 ICA stenoses > 70%; the best correlation was with the application of Hwang criteria, which correctly identified 69 (94.5%) > 70% stenoses. In order of increasing tendency to underscore the grade of stenosis, the corresponding results for the other criteria sets were 62 (84.9%) for Mittl, 59 (80.8%) for AbuRahma, 55 (75.3%) each for Nicolaides and Filis, and 50 (68.5%) for Nederkoorn. CTA detected 85 stenoses >50%; the sensitivity of all applied CDS criteria sets exceeded 90%. CONCLUSION: Grading of ICA stenosis > 70% with CDS and CTA results in clinically relevant discrepancies, with higher grades of stenoses assessed by CTA. The choice of CDS grading criteria is of significant clinical importance, especially in the identification of high-grade ICA stenosis.     

Angiology after-care after infrainguinal arterial reconstruction

This review article describes the natural course of infrainguinal bypasses, duplex ultrasound flow characteristics of stenosed vein bypasses, and the clinical relevance of duplex surveillance of infrainguinal vein bypasses. Among multiple factors bypass patency rates and limb salvage rates are influenced by the surgical technics of revascularization, graft material, localisation of the distal anastomosis, distal run-off, time interval between detection of bypass stenosis and revision. Preliminary duplex ultrasound criteria of a bypass dysfunction are a distal flow velocity < 45 cm/s, a bypass flow < 25 ml/min, a reduction of the inner diameter < 3 mm. The intrastenotic mean systolic peak velocity and the peak velocity ratio (PVR) are suitable for the grading of bypass stenoses. A vein bypass stenosis > 70% shows an intrastenotic mean peak velocity of 250 cm/s and a PVR > 3.3, a severe stenosis shows a mean peak velocity of 360 cm/s and a PVR > 7.2.     

Noninvasive assessment of coronary flow reserve in the left anterior descending artery by transthoracic echocardiography before and after stenting

BACKGROUND: Noninvasive assessment of coronary flow reserve in the left anterior descending artery (LAD) by transthoracic Doppler echocardiography (TTDE) has been already validated as a new method for determining the degree of stenosis over the proximal flow. OBJECTIVES: The aim of the study is to determine, by TTDE, the feasibility and the value of the coronary flow reserve (CFR) (defined as the maximal increase in coronary blood flow above its basal pressure for a given perfusion pressure when coronary circulation is maximally dilated) in the mid-to-distal LAD before and after percutaneous angioplasty and to demonstrate the early recovery of microvascular tone immediately after stenting. METHODS: The study population consisted of 36 patients with significant isolated LAD stenosis (70-90%) identified by coronary angiography. CFR was recorded in the mid-to-distal LAD at rest and during hyperemia obtained after adenosine intravenous infusion before and after stenting. RESULTS: Adequate visualization of the LAD was obtained in 25 out of 36 patients (70%). At rest the mean CFR was 1.5132 +/- 0.33 (1.1-2.58). However, after stenting the mean CFR was significantly higher: 2.18 +/- 0.55 (1.3-3.8), with P <0.01. CONCLUSIONS: CFR can be easily determined by TTE in approximately 70% of patients. Noninvasive Doppler echocardiography shows impaired CFR in patients with LAD disease. After stenting CFR is restored, demonstrating early recovery of microvascular tone. These results are comparable to those published in the same conditions. Larger series with a long-term follow-up may allow identifying patients at high risk for restenosis after stenting.     

颈动脉支架成形术对颈内动脉重度狭窄患者认知功能的影响

目的观察颈动脉支架成形术(CAS)对颈内动脉重度狭窄患者认知功能与生活质量的影响。方法选择32例未发生大面积脑梗死的重度颈动脉狭窄(狭窄程度≥70%)患者行CAS,手术前及术后3个月采用简易智能状态检查量表(MMSE)及视觉保持测验(VRT)观察认知功能的变化,用WHO生存质量量表简表(WHOQOL-BREF)观察患者生活质量变化。结果所有患者均成功行CAS,成功率100%。与术前颈动脉狭窄率比较,术后3个月狭窄率明显降低[(83.4±7.6)%vs(4.3±1.3)%,P<0.01];与术前比较,术后3个月MMSE评分、VRT正确计分、WHOQOL-BREF评分明显升高,差异有统计学意义(P<0.05);VRT错误计分明显降低,差异有统计学意义(P<0.05)。随访期无症状性脑卒中复发。结论严重颈动脉狭窄可能是导致患者认知功能障碍的原因之一,CAS可以改善患者的认知功能和生活质量。     

Coronary CT Angiography in Heavily Calcified Coronary Arteries: Improvement of Coronary Lumen Visualization and Coronary Stenosis Assessment With Image Postprocessing Methods

To compare the diagnostic value of coronary CT angiography (CCTA) with use of 2 image postprocessing methods (CCTA_S) and (CCTA_OS) and original data (CCTA_O) for the assessment of heavily calcified plaques.Fifty patients (41 men, 9 women; mean age 61.9 years ± 9.1) with suspected coronary artery disease who underwent CCTA and invasive coronary angiography (ICA) examinations were included in the study. Image data were postprocessed with “sharpen” and smooth reconstruction algorithms in comparison with the original data without undergoing any image postprocessing to determine the effects on suppressing blooming artifacts due to heavy calcification in the coronary arteries. Minimal lumen diameter and degree of stenosis were measured and compared between CCTA_S, CCTA_OS, and CCTA_O with ICA as the reference method. The area under the curve (AUC) by receiver-operating characteristic curve analysis (ROC) was also compared among these 3 CCTA techniques.On a per-vessel assessment, the sensitivity, specificity, positive predictive value and negative predictive value, and 95% confidence interval (CI) were 100% (95% CI: 89%, 100%), 33% (95% CI: 22%, 45%), 41% (95% CI: 30%, 53%), 100% (95% CI: 85%, 100%) for CCTA_O, 94% (95% CI: 79%, 99%), 66% (95% CI: 54%, 77%), 57% (95% CI: 43%, 70%), and 95% (95% CI: 85%, 99%) for CCTA_S, 94% (95% CI: 79%, 99%), 44% (95% CI: 32%, 57%), 44% (95% CI: 32%, 57%), and 97% (95% CI: 79%, 99%) for CCTA_OS, respectively. The AUC by ROC curve analysis for CCTA_S showed significant improvement for detection of >50% coronary stenosis in left anterior descending coronary artery compared to that of CCTA_OS and CCTA_O methods (P < 0.05), with no significance differences for detection of coronary stenosis in the left circumflex and right coronary arteries (P > 0.05).CCTA with “sharpen” reconstruction reduces blooming artifacts from heavy calcification, thus, leading to significant improvement of specificity and positive predictive value of CCTA in patients with heavily calcified plaques. However, specificity is still moderate and additional functional imaging may be needed.     

Determining in-stent stenosis of carotid arteries by duplex ultrasound criteria.

PURPOSE: To develop customized duplex ultrasound criteria for assessment of in-stent restenosis in the carotid arteries. METHODS: A retrospective review was conducted of 605 patients who underwent carotid artery stenting (CAS) from July 1996 to August 2004 at a single institution. Data on the stented carotid artery were accumulated from patients who had carotid angiography and duplex ultrasound (US) within 30 days of each other. Preliminary review found 118 pairs of ultrasound scans and angiograms in stented carotid arteries. Peak systolic velocity (PSV), end-diastolic velocity (EDV), and internal carotid artery to common carotid artery ratio (ICA/CCA) were examined. Angiographic stenosis was graded by NASCET criteria and compared to velocity parameters at clinically relevant levels of stenosis. The Student t test was used to compare similarly obtained data from 41 nonstented carotid arteries. RESULTS: PSV, ICA/CCA ratio, and EDV increased to a greater degree in stented arteries with stenosis. In 50% to 69% stenotic arteries, mean ICA/CCA ratio was 4.74+/-0.61 in stented versus 3.68+/-0.24 in nonstented carotid arteries (p = 0.043). In arteries with > or = 70% stenosis, there were increases in PSV (475+/-22 versus 337+/-26 cm/s, p = 0.001), EDV (172+/-23 versus 122+/-8 cm/s, p = 0.043), and the ICA/CCA ratio (8.18+/-2.19 versus 5.11+/-0.66, p = 0.063) in stented versus nonstented arteries, respectively. To detect > or = 70% angiographic stenosis, PSV > or = 350 cm/s had 100% sensitivity, 96% specificity, 55% positive predictive value (PPV), and 100% negative predictive value (NPV); an ICA/CCA ratio > or = 4.75 had 100% sensitivity, 95% specificity, 50% PPV, and 100% NPV. To predict > 50% stenosis, combining PSV > or = 225 cm/s and ICA/PCA ratio > or = 2.5 increased sensitivity (95%), specificity (99%), PPV (95%), NPV (99%), and accuracy (98%). CONCLUSIONS: PSV and ICA/CCA increase with stenosis to a greater extent in stented carotid arteries, necessitating revision of existing US criteria to follow CAS patients. To determine > or = 70% in-stent stenosis, PSV > or = 350 cm/s and ICA/CCA ratio > or = 4.75 are sensitive criteria. To determine > or = 50% stenosis, combining PSV > or = 225 cm/s and ICA/PCA ratio > or = 2.5 is optimal.     

Cervical artery dissection: improved diagnosis by B-Flow ultrasound

OBJECTIVE: The objective of this study was to evaluate the efficiency of B-Flow ultrasound in diagnosing supraaortic vessel dissections compared with other ultrasound techniques including B scan, Color-Coded Doppler (CCDS) and Power Doppler (PD). MATERIALS AND METHODS: Eighty-eight patients with suspected arterial dissection of the neck vessels were included in this prospective trial. All patients were examined using B scan, Color-Coded Doppler sonography and Power Doppler. After documentation of the diagnoses, the patients were additionally examined by B-Flow ultrasound. Contrast-enhanced magnetic resonance angiography (MRA) was used as reference standard in all cases. RESULTS: Dissections of the carotid artery (n=19) and of the vertebral artery (n=35) were found in 44 patients. B-Flow imaging identified 52 of 54 arterial dissections that were confirmed by MRA. There were no false-positive diagnoses in ultrasound examination. The sensitivity of ultrasound examination using B scan, CCDS and PD in detecting all dissections was 95.9% and 99.1% with additional B-Flow examination. Sensitivity using B-Flow increased from 98.3% to 100% for carotid dissections and from 93.3% to 94.3% for vertebral artery dissections. Due to the lack of overwriting artifacts, B-Flow imaging detected residual flow within the false lumen more precisely. The reduced effect of the ultrasound probe angle facilitated imaging of fissures, membranes and low flow phenomena and improved the identification of low-reflection wall structures. The cine mode of the B-Flow showed undulating membrane movement most clearly. Contrast-enhanced MRA in conjunction with axial T1 and T2 weighted sequences enabled the best visualization of intramural hematomas. CONCLUSION: B-Flow imaging can significantly increase the sensitivity of ultrasound examination for dissections of the neck vessels. It also improves the visualization of flow within the true and false lumen, of hypoechoic thrombi and of intramural hematoma.     

A new approach of primary angioplasty for ST-elevation acute myocardial infarction based on minimalist immediate mechanical intervention

OBJECTIVES: No reflow has been reported in 12-30% of the patients directly revascularized by angioplasty for acute ST elevation myocardial infarction with the highest incidence after primary stenting in patients with initial thrombolysis in myocardial infarction (TIMI) grade 0 flow. We hypothesized that a minimalist immediate mechanical intervention (MIMI) based on the use of very small size balloons to avoid both large dissection and distal embolization may be sufficient to restore flow in emergency and that recanalization may be sustained by maximized antithrombotic regimen (abcximab, clopidogrel, aspirin and heparin) allowing one to postpone stenting in better conditions. METHODS: MIMI was performed in 93 patients for ST elevation myocardial infarction with initial TIMI grade 0 flow. RESULTS: MIMI resulted in a TIMI grade 3 flow in 77/93 patients (83%). Immediate stenting was performed in the 16 patients with failed MIMI and resulted in a TIMI grade 3 flow in nine (56%). The residual stenosis after MIMI was 81+/-11% and ST segment resolution (> or =50%) at 1 h after reperfusion was obtained in 84%. Stenting was performed the following days in 52 patients with a post-stenting TIMI grade 3 flow in 50 (96%; 100% when stenting done beyond 24 h). No reocclusion occurred between MIMI and stenting. Among the 25 patients without stenting, six had mild stenosis at control angiogram and underwent medical treatment whereas 19 had multiple vessel disease and underwent bypass surgery. CONCLUSIONS: MIMI combined with maximized antithrombotic therapy results in immediate and sustained recanalization with a high rate of ST resolution in a majority of patients with ST elevation myocardial infarction. This approach allows one to postpone stenting in more stable conditions with a low rate of TIMI flow deterioration or to schedule more appropriate medical or surgical alternative management.     

The treatment of carotid artery bifurcation stenoses with systematic stenting: experience of first 100 consecutive cardiological procedures

Carotid endarterectomy still represents the gold standard treatment of carotid artery bifurcation stenosis but percutaneous angioplasty with stenting is rapidly growing as a non-invasive alternative. In this paper we report the results of systematic application of carotid stenting performed in a cardiological setting, particularly as regards clinical management of patients and technical approach. One-hundred (100) procedures of carotid artery stenting (CAS) on 94 consecutive patients, both symptomatic and asymptomatic, with a carotid stenosis > 70%, were performed over a period of 30 months. The technical approach was directly derived from coronary angioplasty with use of large lumen guiding catheters, 0.014 in. intravascular guidewires and distal protection devices usually employed in coronary interventions. In 3 cases, a post-carotid endarterectomy restenosis and in 97 cases, a de-novo lesion, were treated respectively; in 71 cases, the degree of stenosis was 71-89% and in 29 cases, 90-99%. Cerebral protection was obtained with a distal to the lesion endovascular filter in 63 cases. Immediate technical success, i.e. residual stenosis of the treated vessel < 30% and no significant pathologic acceleration of blood flow (< 1.5 m/sec) at the Doppler ultrasound evaluation, was achieved in all procedures (100%). Ninety-six (96) procedures were totally uncomplicated; in-hospital cerebral complications were 1 TIA, 2 minor and 1 major strokes; at 30-day follow-up one additional major stroke occurred. Despite a particularly high incidence of comorbidities, neither unfavorable cardiological complications nor neurologic deaths were reported. Systematic CAS is a feasible treatment of the carotid artery bifurcation stenosis with high procedural success and low perioperative and short term complications. Its performance in a cardiological setting can combine satisfying procedural results and potentially successful handling of cardiovascular complications.     

Cerebrovascular response time to a breath-holding challenge

BACKGROUND: To evaluate the timecourse of cerebrovascular reserve response to breath-holding. PATIENTS AND METHODS: Using simultaneous bilateral transcranial Doppler (TCD) recordings from the MCA during a breath-holding challenge, we measured the time interval between baseline and peak blood flow velocity values in 25 patients with critical unilateral internal carotid artery (ICA) stenosis (> 85% lumen diameter reduction), in 9 patients with a non-critical (70-85%) ICA-stenosis and in 27 normal controls. RESULTS: Normal controls and patients with non-critical stenosis reached peak MCA velocities on both sides almost simultaneously. For the patients with critical stenosis the peak response time ipsilateral to the stenosis was delayed 2.40 +/- 3.43 sec compared to the opposite side. This delay resolved after carotid endarterectomy. CONCLUSIONS: In response to a breath-holding challenge unilateral critical ICA stenosis is associated with a significant ipsilateral prolongation of the rise time from baseline to peak MCA velocity.     

Noninvasive coronary flow reserve assessed by transthoracic coronary Doppler ultrasound in patients with left anterior descending coronary artery stents

Noninvasive measurement of coronary flow reserve (CFR) (hyperemic/flow velocity ratio at rest) by transthoracic Doppler echocardiography showed normalization of flow in the left anterior descending (LAD) coronary artery early after stenting. We hypothesized that noninvasive CFR may reveal in-stent restenosis at follow-up. Therefore, we studied 134 patients, 0 to 72 months after successful proximal-middle LAD stenting, and 38 controls. LAD flow velocity was measured by transthoracic Doppler echocardiography during 90 seconds venous adenosine infusion (140 microg/kg/min). CFR was measured in diastole. According to angiography, patients who received stents were divided into 3 groups: group I, <50% LAD in-stent restenosis (n = 83); group II, nonsignificant (50% to 69%) LAD in-stent restenosis (n = 17); and group III, significant (> or = 70%) LAD in-stent restenosis (n = 34). LAD CFR was similar in group I and controls (2.90 +/- 0.58 vs 3.05 +/- 0.81; p = NS), it was slightly lower in group II (2.42 +/- 0.33) compared with controls and group I (p <0.001 vs both), and clearly abnormal (<2) in group III (1.38 +/- 0.48) compared with controls, and groups I and II (p <0.001). A CFR <2 had 91% sensitivity, 95% specificity, and 96% positive and 97% negative predictive values to detect significant stenosis in patients with LAD stents. Our data show that noninvasive Doppler assessment of CFR allows identification of significant LAD in-stent restenosis, based on a cut-off value of <2.     

Assessment of flow velocity reserve by transthoracic Doppler echocardiography and venous adenosine infusion before and after left anterior descending coronary artery stenting.

OBJECTIVES: We sought to evaluate whether coronary flow velocity reserve (CFR) (the ratio between hyperemic and baseline peak flow velocity), as measured by transthoracic Doppler echocardiography during adenosine infusion, allows detection of flow changes in the left anterior descending coronary artery (LAD) before and after stenting. BACKGROUND: The immediate post-stenting evaluation of CFR by intracoronary Doppler has shown mixed results, due to reactive hyperemia and microvascular stunning. Noninvasive coronary Doppler echocardiography may be a more reliable measure than intracoronary Doppler. METHODS: Transthoracic Doppler echocardiography during 90-s venous adenosine infusion (140 microg/kg body weight per min) was used to measure CFR of the LAD in 45 patients before and 3.7 +/- 2 days after successful stenting, as well as in 25 subjects with an angiographically normal LAD (control group). RESULTS: Adequate Doppler spectra were obtained in 96% of the patients. Pre-stent CFR was significantly lower in patients than in control subjects (diastolic CFR: 1.45 +/- 0.5 vs. 2.72 +/- 0.71, p < 0.01; systolic CFR: 1.61 +/- 1.02 vs. 2.41 +/- 0.68, p < 0.01) and increased toward the normal range after stenting (diastolic CFR: 2.58 +/- 0.7 vs. 2.72 +/- 0.75, p = NS; systolic CFR: 2.43 +/- 1.01 vs. 2.41 +/- 0.52, p = NS). Diastolic CFR was often damped, suggesting coronary steal in patients with > or =90% versus <90% LAD stenosis (0.86 +/- 0.23 vs. 1.69 +/- 0.43, p < 0.01). Coronary stenting normalized diastolic CFR in these two groups (2.45 +/- 0.77 and 2.64 +/- 0.69, respectively, p = NS), even though impaired diastolic CFR persisted in three of four patients with > or =90% stenosis. Stenosis of the LAD was better discriminated by diastolic (F = 49.30) than systolic (F = 12.20) CFR (both p < 0.01). CONCLUSIONS: Coronary flow reserve, as measured by transthoracic Doppler echocardiography, is impaired in LAD disease; it may identify patients with > or =90% stenosis; and it normalizes early after stenting, even in patients with > or =90% stenosis.     

超声对单侧颈内动脉严重狭窄或闭塞时颅内动脉血流动力学变化的研究

目的:分析并评价单侧颅外段颈内动脉(ICA)严重狭窄(≥70%)或闭塞时颅内侧支循环建立的情况。方法:彩色多普勒显像(CDFI)筛选出单侧颅外段ICA严重狭窄或闭塞患者42例,应用经颅彩色多普勒(TCCD)评价颅内主要动脉的血流动力学变化,并经数字减影血管造影术(DSA)检查结果证实。结果:1.与DSA比较:TCCD探测前交通动脉(AcoA)和眼动脉(OA)具有较高的敏感性、特异性,对AcoA探测的价值最大,其次是后交通动脉(PcoA)。2.AcoA的开放与卒中的发生呈负相关。3.患侧大脑中动脉(MCA)的收缩期峰值流速(PSV)及搏动指数(PI)值均较健侧明显减低(P<0.05)。卒中组和短暂性脑缺血发作(TIA)组患侧OA的PI值明显低于健侧(P<0.05)。结论:CDFI和TCCD检测可综合分析颅内主要动脉的血流动力学变化,准确、可靠及无创地评价颅内侧支循环的情况,对单侧ICA严重狭窄或闭塞患者的治疗和预后的判断具有重要的临床价值。     

Preintervention angiographic and intravascular ultrasound predictors for side branch compromise after a single-stent crossover technique

A single stent crossover technique is the most common approach to treating bifurcation lesions. In 90 bifurcation lesions with side branch (SB) angiographic diameter stenosis <75%, we assessed preintervention intravascular ultrasound (IVUS; of main branch [MB] and SB) predictors for SB compromise (fractional flow reserve [FFR] <0.80) after a single stent crossover. Minimal lumen area (MLA) was measured within each of 4 segments (MB just distal to the carina, polygon of confluence, MB just proximal to polygon of confluence, and SB ostium). All lesions showed Thrombolysis In Myocardial Infarction grade 3 flow in the SB after MB stenting. Although angiographic diameter stenosis at the SB ostium increased from 26 ± 15% before the procedure to 36 ± 21% after stenting (p = 0.001), FFR <0.80 was observed in only 16 patients (18%). Negative remodeling (remodeling index <1) was seen in 83 (92%) lesions but did not correlate with FFR after stenting. Independent predictors for FFR after stenting were maximal balloon pressure (p = 0.002) and MLA of SB ostium before percutaneous coronary intervention (p <0.001), MLA within the MB just distal to the carina (p = 0.025), and plaque burden at the SB ostium before percutaneous coronary intervention (p = 0.005), but not angiographic poststenting diameter stenosis or minimal lumen diameter. For prediction of FFR <0.80 after percutaneous coronary intervention, the best cutoff of MLA within the SB ostium before percutaneous coronary intervention was 2.4 mm(2) (sensitivity 94%, specificity 69%). Also, the cutoff of plaque burden within the SB ostium before percutaneous coronary intervention was ≥51% (sensitivity 75%, specificity 71%). In 67 lesions with an MLA ≥2.4 mm(2) or plaque burden <50% before percutaneous coronary intervention, 63 (94%) showed FFR ≥0.80. However, FFR <0.80 was seen in only 12 (52%) of 23 lesions with an MLA <2.4 mm(2) and plaque burden ≥50%. In conclusion, there do not appear to be reliable IVUS predictors of functional SB compromise after crossover stenting.