Characteristics of peripheral microembolization during iliac stenting: Doppler ultrasound monitoring.

OBJECTIVE: To evaluate the characteristics of distal microembolic signals (MES) during iliac stenting using Doppler ultrasound monitoring. DESIGN: Prospective clinical study. METHODS: A 2-MHz probe was used to monitor continuously at the ipsilateral tibioperoneal trunks during technically and hemodynamically successful iliac stenting in 10 patients without infrainguinal occlusive lesion. MESs at guide-wire, balloon, or stent crossing (phase 1), predilatation (phase 2), stent deployment (phase 3), postdilatation (phase 4), and contrast medium or heparinized saline injection (at injection) were analyzed. Differentiation of gaseous emboli from particulate emboli was achieved by calculation of the sample volume length. RESULTS: No distal embolic complications were observed. Five hundred and forty-one MESs were detected. The MES incidence and intensity in phase 3 were significantly higher than those in phase 1, phase 2, and phase 4 (p<0.05). The MES intensity at injection was significantly higher than that in each of four phases (p<0.0001). CONCLUSIONS: Both the MES incidence and intensity were highest at stent deployment. Further study is required of microembolism during endovascular procedures in the lower extremities.     

Doppler microembolic signals in patients with two different types of bileaflet valves

OBJECTIVES: This study was performed to evaluate the prevalence and counts of Doppler microembolic signals in patients with St Jude Medical valves (St Jude Medical, Inc, St Paul, Minn) and patients with ATS valves (ATS Medical, Inc, Minneapolis, Minn) and their relation to clinical parameters. METHODS: A total of 179 outpatients of the department of cardiothoracic surgery were examined. They included 98 men and 81 women, aged 61 +/- 11 years, with ATS (n = 91) or St Jude Medical (n = 88) valves in the aortic (n = 110), mitral (n = 39), or both positions (n = 30). Neurologic examination was followed by transcranial Doppler monitoring for microembolic signals. Monitoring was performed bilaterally over the middle cerebral arteries for 1 hour per session. RESULTS: Microembolic signal counts and prevalence were significantly higher in patients with St Jude Medical as compared with ATS valves. Valve type and presence of diabetes mellitus were the only predictors of microembolic signal prevalence on multivariate analysis. No influence of microembolic signals on cerebral embolic complications was established. Additionally, patients with a postoperative history of cerebral embolic complications did not have a higher number of microembolic signals than remaining patients. Interobserver variability was satisfactory. CONCLUSIONS: Patients with St Jude Medical valves were shown to have significantly higher microembolic signal counts than patients with ATS valves. However, our results suggest that microembolic signal counts cannot be used to predict cerebral embolic complications. Their relation to neuropsychologic deficits remains to be evaluated.     

Doppler ultrasound of penis arteries

In addition to pharmaco testing, pharmaco-Doppler sonography of the penile arteries is part of the basic work-up for erectile dysfunction. Insufficient training with the Doppler method, lack of standardized criteria for evaluation of the penis, and analysis of the Doppler curves all make it difficult to use Doppler sonography for the evaluation of impotent men. The aim of this study was to explain the principal criteria of the method and demonstrate the most important details for analyzing the form of the Doppler waves. Pharmaco-Doppler sonography includes the evaluation of blood-flow velocities within the dorsal and deep cavernous arteries of the penis before and after intracavernous application of a vasoactive drug. The following main criteria have proven to be most important for analysis of the Doppler curves: evaluation of the amplitude height, the actual wave form, differences between the left and right arteries and along the individual vessel, amplitude increase, and elevation of the curve baseline after pharmaco stimulation. The most frequent mistakes made during evaluation of the penile arteries are changes in the probe angle, pressure put on the artery by the probe during evaluation and a false estimation of the evaluation time after pharmaco stimulation. Recently, duplex sonography of the penile arteries has been introduced, and this method allows an accurate measurement of the blood-flow velocity and arterial diameter changes before and after application of the drug. Furthermore, additional calculation of the resistancy index permits determination of the vascular resistance and optimizes the evaluation of the penile arterial status. The technical details, the method, and the analyzation criteria are all explained in detail.     

Doppler ultrasound in aortic dissections: a study of cephalic and peripheral arteries

We investigated the role of continuous-wave Doppler ultrasound in predicting the presence of an aortic dissection prospectively in 28 patients whose diagnosis was confirmed either by arteriography or surgery (26 cases) or at autopsy (two cases). We hypothesized that dissections, by creating two channels for flow, would produce velocity disturbances detectable in accessible arteries such as the carotid, brachial, and femoral arteries. Of the 28 patients, 20 had Type I, two Type II, and six Type III dissections. Two abnormalities of the Doppler signals were found: in 18 of Type I dissections, notching was found in the systolic upslope of the velocity tracing from those arteries that were either involved in or distal to the dissection sites. Notching was much less frequent for Type II and III dissections: only one patient with Type II and two patients with Type III dissections showed notching. In addition diastolic backflow with marked aortic valvular insufficiency was present. Notching in brachiocephalic artery continuous-wave Doppler signals appears to have a high positive predictive value for Type I dissections.     

Location of urethral arteries by colour Doppler ultrasound

STUDY DESIGN: A case report. SETTING: Regional Spinal Injuries Centre, Southport, UK. CASE REPORT: A 56-year-old male with complete paraplegia at T-4 underwent visual internal urethrotomy of bulbous urethral stricture with a cold knife at 12 o'clock position. There was brisk arterial bleeding. Despite receiving antibiotics, this patient developed hypotension, tachycardia and tachypnoea. He was resuscitated and mechanical ventilation was instituted. After he recovered from this life-threatening episode of urinary tract-related sepsis, colour Doppler ultrasound imaging of bulbous urethra was performed to locate urethral arteries. In the bulbous urethra, single urethral artery was seen at 12 o'clock position. CONCLUSION: Since the sites of urethral arteries vary among patients, it is advisable to assess individually the location of urethral arteries preoperatively and plan the site of incision accordingly. Persons with injury to cervical or upper dorsal spinal cord have decreased cardiac and respiratory reserve as well as alteration in immune function. Therefore, all possible measures should be taken to prevent acute blood loss and bacteraemia in this group of patients.     

Follow-up of stented carotid arteries by Doppler ultrasound

OBJECTIVE: Blood flow velocity (BFV) in the carotid artery is altered by stent placement. The significance of these alterations is unknown. In our experience, both standard BFV criteria for stenosis and customized criteria recommended by other authors have led to high rates of false-positive studies. We reviewed our experience with Doppler ultrasonography immediately after extracranial carotid artery stent placement to define criteria for restenosis by BFV. METHODS: Complete carotid angiograms and BFV results were available for 114 patients treated between January 1998 and December 1999. Angiographic images obtained immediately after stent placement and at follow-up were measured for residual or recurrent stenosis by a blinded reviewer according to the North American Symptomatic Carotid Endarterectomy Trial method. Results of BFV studies obtained within 1 week of stent placement were interpreted by using two standard criteria (A, peak in-stent systolic velocity greater than 125 cm/s; B, internal carotid artery-to-common carotid artery ratio greater than 3.0) and two customized criteria (C, peak in-stent velocity greater than 170 cm/s; D, internal carotid artery-to-common carotid artery ratio greater than 2.0). The results of follow-up angiography and the most recent Doppler study were compared for nine patients. RESULTS: On the basis of an examination of Doppler studies obtained immediately after stent placement, 36 patients met Criterion A for stenosis according to measured BFV (corresponding mean angiographic stenosis, 14.73 +/- 18.45%), 3 patients met Criterion B (mean stenosis, 1.67 +/- 2.89%), 8 patients met Criterion C (mean stenosis, 12.61 +/- 13.18%), and 14 met Criterion D (mean stenosis, 7.98 +/- 21.74%). No patient with Doppler criteria for significant stenosis had more than 50% residual stenosis. Three of nine patients who underwent follow-up angiography had stenosis of 50% or more; of these three patients, two underwent second angioplasty procedures. The peak in-stent systolic velocity or internal carotid artery-to-common carotid artery BFV ratio for each of the three patients with restenosis, but not for the six other patients, had increased by more than 80% since the immediate post-stenting Doppler study. CONCLUSION: Strict BFV criteria for restenosis after carotid artery stenting are less reliable than change in BFV over time. An immediate post-stenting Doppler study must be obtained to serve as a reference value for future follow-up evaluation.     

Color Doppler ultrasound for detection of renal arteriovenous fistulas

OBJECTIVES: Renal arteriovenous (AV) fistula is uncommon, but sometimes causes severe hematuria. To assess the value of color Doppler ultrasound (CD-US) for the detection of renal AV fistula, we retrospectively reviewed our experience with this disease. MATERIALS AND METHODS: Between 1994 and 2001, five patients with renal AV fistula were diagnosed in our institution. Post-biopsy AV fistula of the transplanted kidney was found in 1 patient. Renal AV fistula was detected in 2 patients who presented with gross hematuria. In the remaining 2 patients, renal AV fistula was discovered incidentally during abdominal ultrasonography. We evaluated gray-scale and CD-US imaging in those five patients. RESULTS: In all 5 patients, CD-US showed a whirling flow pattern within an echo-free structure suggesting AV fistula. However, it was difficult to distinguish AV fistula from aneurysm using only CD-US. While pulsed spectral Doppler evaluation of the lesion might be helpful, prompt venous filling on dynamic CT scan and/or renal arteriography was the most definitive sign for diagnosing the renal AV fistula. CONCLUSIONS: CD-US is excellent for demonstrating turbulent blood flow signals within the kidney. However, another radiographic study is required to give a definite diagnosis of renal AV fistula. Due to its low cost, low risk and wide availability, we recommend that CD-US be the first-line imaging procedure for the evaluation of hematuria and renal cystic lesion as well as for followup for renal AV fistula.     

Quantification of microembolic signals during transmyocardial laser revascularization

Transmyocardial laser revascularization (TMLR) is known to induce cerebral microembolic signals (MES). We quantified laser induced MES in patients undergoing TMLR during cardiopulmonary bypass for coronary artery bypass grafting (group A) and during TMLR treatment alone (group B). The total number of MES during a single laser application with identical energy was significantly higher in group A compared to group B (P<0.001). Also the peak of MES occurred significantly later in group A (P<0.0001). An increase of laser energy was associated with an increase in numbers of MES particular in group B (r=0.641). Different TMLR modalities generate different amounts of cerebral microembolic signals. Thus, adjustment of TMLR to these modalities may reduce potentially harmful cerebral microemboli and warrants further evaluation.     

彩色多普勒超声诊断周围型肝内胆管细胞癌的价值

目的 探讨彩色多普勒超声对周围型肝内胆管细胞癌的诊断价值.方法 回顾性分析95例经病理证实的周围型肝内胆管细胞癌,总结其彩色多普勒超声特征.结果 总共102个病灶,大小范围为20 mm×20 mm～130 mm×100 mm.灰阶图像上大部分病灶表现为回声不均匀(75个,73.5％)、边界模糊(70个,68.6％)、分叶状(55个,53.9％).彩色多普勒超声示大部分病灶能检测到血流(75个,73.5％),以簇状、短线状及彩点状血流为主,其中大部分血流的阻力指数大于0.6(65个,86.7％).102个病灶中,见条索样高回声的有37个(36.3％),后方回声出现轻度衰减的有29个(28.4％),出现“脐凹”现象的有22个(21.6％).超声诊断的符合率为84.2％(80/95).结论 周围型肝内胆管细胞癌的彩色多普勒超声表现具有一定的特征,充分认识其声像图特征可提高超声诊断的准确率.     

Atheroembolic signals detected by Doppler ultrasound scan monitoring in a patient with blue toe syndrome: report of a case

It is generally accepted that clinical symptoms give the only clue to the presence of atheroemboli in patients with blue toe syndrome (BTS). We report a case of atheroemboli originating from the abdominal aortic aneurysm in which Doppler ultrasound successfully detected atheroembolic signals, which vanished immediately after surgery. To our knowledge, this is the first such case to be documented. When a 67-year-old man was given warfarin after aortocoronay bypass, digital cyanosis suddenly developed, which became worse and was very painful. Angiography and computed tomography scanning revealed an infrarenal aortic aneurysm with mural thrombus. Doppler ultrasound detected atheroemboli as high-intensity transient signals in the bilateral tibioperoneal trunks. After aneurysmectomy and a bifurcated graft replacement, the cyanotic and painful toes improved immediately. Microscopically, cholesterin crystals were seen in the arterioles of the amputated digits. Thus, Doppler ultrasound could be a valuable test to determine the appropriate treatment for patients at risk of atheroembolic BTS. Received: August 2, 2001 / Accepted: March 5, 2002     

Intraoperative detection of embedded coronary arteries in MIDCAB using a color Doppler microprobe.

Intraoperative detection of deeply embedded coronary arteries is difficult, especially in minimally invasive coronary artery bypass grafts. This report describes an effective method to identify embedded coronary arteries by using a color Doppler microprobe. Five embedded left anterior descending coronary arteries were successfully identified by intraoperative ultrasonography. We believe that the color Doppler microprobe is helpful for surgeons in this difficult situation.     

Doppler ultrasound procedures in the diagnosis of occlusive processes of the supra-aortic arteries

Reported in this paper is experience obtained from application of Doppler sonography to more than 2,000 examinations of patients with suspicion of cerebrovascular insufficiency. Indications for Doppler-type investigation are described together with criteria of Doppler sonography for positive detection of occlusive processes in greater brain-feeding arteries and for adequate assessment of results obtained from vascular surgery. The sensitivity of Doppler sonography amounted to 88.8 per cent and its specificity to 92.9 per cent, as recorded from 117 patients who had been angiographically followed up. Doppler ultrasonography for its high productivity in terms of wide-ranging diagnostic information was found to be the optional method for non-invasive diagnosis of occlusion in supra-aortic arteries, provided absence of contraindications.     

An implanted ultrasound Doppler probe for microvascular monitoring: an experimental study

An experimental investigation is presented into the use of pulsed ultrasound Doppler flowmetry with a percutaneously implanted probe as a monitor of microvascular anastomotic patency. The method accurately indicated and distinguished between experimental arterial and venous occlusion in epigastric island flaps. In free flaps it had advantages over manipulative, intraoperative tests of anastomotic patency and was a reliable post-operative monitor of flap circulation in the experimental model. The technique appears to have great potential as a post-operative monitor for free flaps, including those without a visible surface.     

Doppler ultrasound in vascular surgery.

Doppler ultrasound was first introduced into the study of arterial and venous disorders in 1966. The devices currently used in clinical practice are continous wave systems which, in their simplest form, are pocket-sized units. Instruments with the capability of distinguishing the direction of flow are also available. The signal may be processed for audio use, or an analogue recording can be made of the Doppler frequency shift. The described clinical information will, in large part, dictate the type of equipment used.