shu-508 and Hypertension--Renovascular

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 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