shu-508 and Renal-Artery-Obstruction

Renovascular hypertension resulting from renal artery stenosis is a potentially curable form of secondary hypertension. Although uncommon in the general hypertensive population, the prevalence of renovascular hypertension rises in selected groups of hypertensive patients. Because of the possibility of cure, screening measures for renal artery stenosis are warranted in hypertensive patients with clinical features suggestive of renovascular disease. For a long time, angiography has been considered the 'gold standard' in screening for arterial stenosis. However, it is invasive and associated with inherent morbidity. Thus, less invasive screening measures with high diagnostic sensitivity and specificity are currently being sought. Magnetic resonance angiography and captopril renal scintigraphy are safer alternatives to angiography, but are expensive and not widely available. Duplex ultrasound is more widely available and provides both anatomic and functional assessment of renal artery stenosis; however, sensitivity and specificity vary considerably among different laboratories. Echo-enhanced duplex ultrasound using the galactose-based agent Levovist(R) produces higher quality images of the renal artery than conventional color Doppler, while significantly reducing mean examination time and improving diagnostic confidence. In addition, Levovist does not compromise the safety of duplex ultrasound. Other advances in Doppler imaging techniques that may improve ultrasound sensitivity and specificity in detection of renal artery stenosis are power Doppler, echo-enhanced harmonic spectral Doppler imaging, and echo-enhanced harmonic power Doppler imaging.

Topics: Angiography; Angiotensin-Converting Enzyme Inhibitors; Blood Flow Velocity; Captopril; Contrast Media; Humans; Hypertension, Renovascular; Image Enhancement; Polysaccharides; Renal Artery; Renal Artery Obstruction; Ultrasonography, Doppler

To compare the diagnoses obtained with unenhanced ultrasonography (US), contrast-enhanced US and captopril-enhanced renal scintigraphy and to determine whether use of a contrast agent improves ability to assess the renal arteries with duplex Doppler US.. The study was an open-label controlled trial involving 78 patients with hypertension suspected to have a renovascular cause. The patients underwent captopril-enhanced scintigraphy or routine unenhanced US (the usual diagnostic methods at the centres where the study was conducted) and contrast-enhanced US (with Levovist, Berlex Canada, Lachine, Que.). The patients were followed for 3 months after the diagnostic tests were performed.. Enhanced US yielded a diagnosis for a significantly greater proportion of patients than did unenhanced US (77 [99%] v. 64 [82%] of 78 patients; p = 0.002) or captopril-enhanced scintigraphy (71 [99%] v. 58 [81%] of 72 patients; p = 0.002). Diagnosis was possible with both enhanced and unenhanced duplex Doppler US in only 64 (82%) of the 78 patients, and the diagnosis was the same with both methods for 63 (98%) of these 64 patients. In contrast, diagnosis was possible for only 58 (81%) of the 72 patients who underwent both enhanced US and captopril-enhanced scintigraphy; the same diagnosis was reported in 53 (91%) of these 58 cases. During follow-up, 11 patients (21 kidneys) underwent angiography. Significant stenosis was detected in 6 (55%) of the patients (8 [38%] of the kidneys). Both the enhanced and unenhanced US results agreed more often with angiography than did captopril-enhanced scintigraphy (9 [82%] v. 8 [73%] of the 11 patients). The proportion of patients in whom the left and right renal artery could be assessed by duplex Doppler US increased significantly (by 58% and 43%, respectively) with use of the contrast agent.. Enhanced US had a higher rate of successful diagnosis than unenhanced US and captopril-enhanced renal scintigraphy. Enhanced US might therefore be suitable as a screening method for hypertensive patients with suspected renal artery stenosis.

Topics: Adult; Aged; Angiotensin-Converting Enzyme Inhibitors; Canada; Captopril; Contrast Media; Female; Humans; Hypertension, Renovascular; Male; Middle Aged; Pilot Projects; Polysaccharides; Radionuclide Imaging; Renal Artery Obstruction; Ultrasonography, Doppler, Duplex

To assess SH U 508A in the diagnosis of suspected renal arterial stenosis by means of ultrasonography (US) and to confirm the safety of SH U 508A in a clinical setting.. A randomized crossover study was performed in 198 patients from 14 European centers who were referred for renal arterial angiography because they were suspected of having renal arterial stenosis. All patients underwent nonenhanced and SH U 508A-enhanced Doppler US of the renal arteries. Doppler criteria included measurement of renal arterial peak systolic velocity (threshold, 1.4-2.0 m/sec) in all centers and renoaortic ratio (threshold, 3.0-3.5) in nine.. The number of examinations with successful results increased following enhanced Doppler US examination--160 (83.8%) compared with 122 (63.9%) with nonenhanced Doppler US (P = .001), including patients with obesity or renal dysfunction. Renal arterial stenosis (> or =50%) was detected at angiography in 72 patients. Results at enhanced Doppler US were in agreement with results at angiography more often than with results at nonenhanced Doppler US in the diagnosis or exclusion of renal arterial stenosis (P = .001). For patients examined with nonenhanced and enhanced Doppler US, sensitivity (80.0% and 83.7%, respectively) and specificity (80.8% and 83.6%, respectively) remained unchanged. There were no clinically important adverse events following use of SH U 508A.. In patients suspected of having renal arterial stenosis, SH U 508A increased the number of diagnostic renal arterial Doppler studies.

Topics: Adult; Aged; Aged, 80 and over; Blood Flow Velocity; Contrast Media; Cross-Over Studies; Dose-Response Relationship, Drug; Female; Fourier Analysis; Humans; Male; Middle Aged; Polysaccharides; Renal Artery; Renal Artery Obstruction; Risk Factors; Sensitivity and Specificity; Systole; Ultrasonography, Doppler, Color

To investigate if the duration of Doppler enhancement of the ultrasound contrast agent Levovist can be prolonged by continuous infusion compared to bolus injections in patients.. 12 patients with suspected renal artery stenosis were included. Each patient received 1 or 2 bolus injections of 4 g each and a "fast" infusion of 3 ml/min (average dose: 7 g) of Levovist. In 8 patients an additional "slow" infusion of 1 ml/min (average dose 4.2 g) was given. The duration of "strong" Doppler signal enhancement and the visualization of vessels were compared.. The duration of strong enhancement was substantially prolonged by the slow infusion (bolus 6:21 min, fast infusion: 8:57 min, slow infusion: 15:12 min, p < 0.001). The dose effectiveness (duration of strong enhancement per 1 g Levovist) was markedly improved from 0:57 min (bolus) to 3:36 min (slow infusion). Visualisation of the renal arteries was more complete with the slow infusion.. Levovist infusions at 1 ml/min are superior to bolus injections in the assessment of renal arteries. They prolong the enhancement, make more efficient use of a given dose of contrast material and thus allow additional clinically relevant information to be obtained at reduced cost.

Topics: Adult; Aged; Contrast Media; Female; Humans; Infusions, Intravenous; Injections, Intravenous; Male; Middle Aged; Polysaccharides; Renal Artery Obstruction; Ultrasonography, Doppler, Color

The purpose of this study was to investigate the feasibility of contrast-enhanced ultrasound (CEUS) in the evaluation of renal artery stenosis as compared with traditional techniques: echo color Doppler (ECD) investigation and selective angiography .CEUS is a technique based on the injection of an intravascular biocompatible tracer, namely an intravenous contrast galactose microparticle suspension containing microbubbles (Levovist), that has a similar rheology to that of red blood cells, allowing quantification of renal tissue perfusion.. A population of 120 hypertensive patients (82 men, mean age 55) with a systolic abdominal murmur and/or a diagnosis of poly-districtual atherosclerosis was studied by ECD and CEUS (Levovist). Selective angiography was performed in patients with renal artery stenosis demonstrated by one of the two ultrasonographic techniques.. Forty of the 120 patients in the study population showed renal artery stenosis at one of the two ultrasound techniques: ECD identified renal artery stenosis in 33 cases and CEUS in 38. Instead, selective angiography had detected renal artery stenosis in 38 patients, the same with renal artery stenosis diagnosed by CEUS. Thus, CEUS sensitivity, specificity and accuracy were similar to those of angiography while six false negatives and two false positives were obtained with ECD.. Our results suggest that this renal CEUS is a promising, new, non-invasive method for screening patients with suspected renal artery stenosis. This technique appears to be superior to traditional ECD flow imaging for diagnosing renal artery stenosis and so may be an important aid in cardiovascular diagnostics.

Topics: Contrast Media; False Negative Reactions; False Positive Reactions; Feasibility Studies; Female; Humans; Injections, Intravenous; Italy; Male; Middle Aged; Polysaccharides; Predictive Value of Tests; Radiography; Renal Artery; Renal Artery Obstruction; Sensitivity and Specificity; Ultrasonography, Doppler, Color

To evaluate the diagnostic efficacy of ultrasound imaging of renal arteries after Levovist administration.. During a 20-month period, 100 hypertensive patients with suspected renal artery stenosis were referred to the Department of Interventional Radiology. In all patients, angiography and ultrasound examinations of renal arteries were performed (100 right, 100 left and 23 additional), before and after Levovist injection, using color and spectral Doppler. Results of Doppler examinations before and after Levovist administration were compared with results of angiography ('gold standard '). Hemodynamically significant renal artery stenoses (> 50% in angiography)were diagnosed following Doppler parameters: Vmax > 2 m/s, V min > 1.5 m/s, RAR > 3.5, acceleration time > 0.08 s.. The diagnostic efficacy of Doppler examinations of the right renal artery (RRA)increased from 68% before to 98% after Levovist enhancement and diagnostic efficacy for the left renal artery (LRA) increased from 61% to 97%. In conventional study, 7 additional renal arteries (30.4%) were visualized, after Levovist administration this number increased to 15 (65.2%). Before Levovist injection, 3 stenoses of RRA and 1 stenosis of LRA were diagnosed. After Levovist enhancement, the number of RRA stenoses increased to 5 and that of LRA stenoses increased to 2, later confirmed by angiography.. The use of Levovist increases the diagnostic efficacy of Doppler ultrasound examinations of renal arteries and makes it comparable to angiography.

Topics: Adult; Aged; Angiography; Contrast Media; Female; Humans; Hypertension, Renovascular; Male; Middle Aged; Polysaccharides; Predictive Value of Tests; Renal Artery; Renal Artery Obstruction; Ultrasonography, Doppler, Color

The purpose of the present paper was to assess whether conventional renal Doppler ultrasound and the commonly used parameters of peak systolic velocity and renal aortic ratio may be an appropriate modality for the follow-up of renal artery stents. A total of 19 arteries in 15 patients was examined with both renal Doppler ultrasound and angiography for the presence or absence of recurrent renal artery stenosis. Disease was considered present on angiography if the arterial diameter was more than 60% stenotic. Doppler criteria for stenosis were either a peak systolic velocity of > 180 cm/s or a renal aortic ratio of > 3.0. Echo enhancement with Levovist (Schering, Berlin, Germany) was used if studies were technically unsuccessful or to improve diagnostic confidence. Renal Doppler ultrasound detected 100% of renal artery stenoses. The specificity was 75%, the positive predictive value was 67% and the negative predictive value was 100%. Echo enhancement improved the technical success rate from 89 to 95% and also increased diagnostic confidence in six examinations. The present limited study suggests that similar renal Doppler parameters as used for the study of unstented renal arteries may be applied to the examination of renal arteries with renal stents in situ. It therefore suggests that Doppler ultrasound may provide an adequate non-invasive means of renal artery stent follow-up, particularly when combined with echo-enhancing agents. Further study is warranted to confirm these initial conclusions.

Topics: Adult; Aged; Contrast Media; Female; Follow-Up Studies; Humans; Male; Middle Aged; Polysaccharides; Predictive Value of Tests; Recurrence; Renal Artery Obstruction; Sensitivity and Specificity; Stents; Ultrasonography, Doppler

The use of renal artery Doppler ultrasound for the diagnosis of renal artery stenosis is a well-established technique in selected populations, but the technical failure rate of the examination leading to incomplete studies is a major drawback. The results of ultrasound contrast-enhanced renal artery Doppler for renal artery stenosis, using the echo-enhancing agent, Levovist, are reported here. Sixteen patients (22 arteries) were examined with Levovist. The technical success rate of these examinations was 91%, and all four renal artery stenoses were correctly identified. It is concluded that the use of ultrasound contrast (Levovist) increases the technical success rate of renal artery Doppler ultrasound in this setting, with similar accuracy to unenhanced Doppler examinations.

Topics: Adult; Aged; Contrast Media; Female; Humans; Male; Middle Aged; Polysaccharides; Renal Artery Obstruction; Ultrasonography, Doppler

Topics: Contrast Media; Humans; Polysaccharides; Renal Artery Obstruction; Ultrasonography

Topics: Aged; Contrast Media; Female; Humans; Male; Middle Aged; Polysaccharides; Renal Artery Obstruction; Ultrasonography

To assess whether the use of an echo-enhancing agent reliably allows the diagnosis of renal artery stenosis with colour-coded Doppler sonography.. We examined the main, segmental, and, if present, the accessory renal arteries of 31 patients before and after intravenous injection of Levovist using colour-coded Doppler sonography and compared the results with digital subtraction angiography. A rise in peak systolic velocity in the main renal artery and a reduction of the acceleration index in segmental arteries were used as parameters to detect renal artery stenosis.. After i.v. administration of Levovist the main stem of the renal arteries could be well delineated in 36 of 62 cases (58%) during colour-coded Doppler sonography against 31 cases without Levovist. Taking only the visible cases in account the sensitivity of native as well as of enhanced colour-coded Doppler sonography of the renal main stem was 100%, the specificity was 96% and 94%, respectively. Only one of 11 accessory renal arteries was identified after echo enhancement. The segmental arteries were seen only after echo enhancement in 12 cases so that 60 of the total of 62 renal arteries (95%) could be evaluated. The sensitivity and specificity of the native examination were 67% and 70%. After echo enhancement sensitivity was 75% and specificity was 81%.. Using an echo-enhancing agent the sensitivity and specificity for detection of relevant renal artery stenosis could only be slightly improved compared to the native examination.

Topics: Aged; Aged, 80 and over; Angiography, Digital Subtraction; Blood Flow Velocity; Contrast Media; Female; Humans; Image Enhancement; Male; Middle Aged; Polysaccharides; Renal Artery; Renal Artery Obstruction; Sensitivity and Specificity; Ultrasonography, Doppler, Color

A galactose-based sonographic contrast agent, which produces stable microbubbles capable of traversing the cardiopulmonary circulation, was used to enhance Doppler signals in blood vessels of varying size after intravenous injection. A series of experiments using dogs, rabbits, and woodchucks was conducted to establish the ability of the agent to enhance the reflectivity of normal tissue, tumor tissue, and blood. Although no enhancement was perceptible in tissue on the sonogram, significant enhancement of color and spectral Doppler signals was demonstrated in a variety of vessels. These included the aorta, vena cava, and portal vein as well as such small vessels as those of the retina of the eye, renal cortex, liver parenchyma, and gallbladder wall. Both spectral and color Doppler enhancement was shown in naturally occurring woodchuck hepatomas. Peak Doppler signal enhancement after bolus injection was approximately 10 dB with a dose of 0.01 ml/kg. Recirculation of the agent provided enhancement after intravenous bolus injection for more than 3 min. With a steady intravenous infusion of 0.2 ml/min/kg, Doppler signal enhancement of about 14 dB was maintained continuously for more than 5 min. The results of these animal experiments, in particular in small vessels and with recirculation after intravenous injection, suggest excellent potential for future clinical applications.

Topics: Angiography; Animals; Blood Flow Velocity; Blood Vessels; Contrast Media; Disease Models, Animal; Dogs; Eye; Galactose; Gallbladder; Infusions, Intravenous; Injections, Intravenous; Liver Neoplasms, Experimental; Marmota; Polysaccharides; Rabbits; Renal Artery Obstruction; Ultrasonography