Evaluation Of Renovascular Hypertension Research Articles

Multiple vascular variations at the vicinity of the left kidney

Although isolated variations of the renal artery, renal vein and testicular artery are commonly described in the literature, the concurrent presence of variations in all three of these vessels has seldom been reported. Here, we report concurrent vascular variations in the vicinity of the left kidney. The left renal vein was found to have a retropelvic tributary, and a communicating vein connecting the inferior vena cava and retropelvic tributary was also noted. In addition, the left renal artery separated into anterior and posterior divisions just before reaching the hilum. The anterior division further divided into two segmental branches which had a peculiar 'ram horn' shape. The posterior division of the renal artery entered the substance of the kidney without forming any further branches. The left testicular artery arose from the aorta above the level of the renal artery and then passed in front of left renal vessels following a tortuous course. The anatomical knowledge of this unusual vascular pattern may be useful during renal vascular reconstruction, treatment of renal artery stenosis, endoscopic surgeries and clinical evaluation of renovascular hypertension.

The role of CT angiography in the evaluation of pediatric renovascular hypertension

Historically, the evaluation of renovascular hypertension has been accomplished by US, renal scintigraphy and digital subtraction angiography. Based on its high accuracy reported in adults renal CT angiography (CTA) with pediatric-appropriate low radiation dose techniques has become an important tool in the workup of renovascular hypertension in children. Renal CTA has several advantages over more conventional imaging modalities, including rapid and non-invasive acquisition, high resolution and easy reproducibility. Additionally, in our experience high-quality renal CTA can be performed using low-dose radiation exposures and can be acquired without sedation in most instances. This article illustrates by examples the usefulness of renal CTA for diagnosis of childhood renovascular hypertension and provides an overview of renal CTA findings in the most common childhood renovascular diseases.

'String of beads' or 'bunch of grapes': A case report of renal artery fibromuscular dysplasia

Introduction: Fibromuscular dysplasia (FMD), a disease of unknown etiology leading to renovascular hypertension (RVH) usually affects medium and large arteries of young females. Case Report: We report the case of 29­ year­old man in whom fibromuscular dysplasia presented as ‘Bunch of Grapes’ instead of its telltale sign of ‘String of Beads’. To our knowledge it is the first case of renal artery multiple aneurysms arising from single site associated with stenoses. Angioplasty, although standard of care in such lesions, was not feasible and open surgical revascularisation using exclusion of aneurismal segment and renal revascularisation using reversed great saphenous vein graft interposition provided excellent results. Conclusion: The First case of Renal artery Fibromuscular dysplasia presenting as ‘Bunch of Grapes’ sign is reported. Detailed evaluation of renovascular hypertension and its successful surgical correction using vein graft exclusion bypass is described.

The effect of percutaneous dilatation of renal arterial stenosis on captopril renography in hypertension

Background. The clinical effects of percutaneous transluminal renal artery angioplasty (PTRA) in patients with renal vascular stenosis and hypertension is controversial. Methods. We consecutively recruited all 23 patients referred for evaluation of renovascular hypertension that eventually underwent unilateral PTRA, to be investigated with captopril MAG3 renography (CR), both before and after the endovascular procedure. Data were evaluated on an intention‐to‐treat basis. Results. We found that the relative MAG3 clearance of the stenotic kidney increased (from 29.9±14% to 35.1±14%, p = 0.01) and that the creatinine levels fell following the intervention (from 110±19 to 99±17 µmol/l, p = 0.0003). Blood pressure levels were also lowered (from 173±32/93±17 to 158±31/86±15 mmHg, p<0.006) while the mean number of anti‐hypertensive drugs was unchanged following PTRA (2.9±1.4 before and 2.8±1.3 drugs after the intervention, respectively, p = 0.6). Conclusion. This prospective trial showed statistically significant improvements of individual kidney function as measured by CR and blood pressure in subjects with suspected renovascular hypertension treated with PTRA. Although the endovascular procedure was found to be safe, the magnitude of the absolute improvements was rather modest.

Contemporary approach to diagnosis and evaluation of renovascular hypertension

Recommendations regarding the clinical protocols for radionuclides of choice and diagnostic criteria for renovascular hypertension have been established by the consensus report on captopril renography. A review of the existing data indicates that postcaptopril renography alone is a safe and effective means of noninvasively screening hypertensive patients. A normal radionuclide study after captopril suggests with a reasonable degree of certainty that potentially reversible renovascular hypertension is unlikely. A positive study in an appropriately screened hypertensive patient with preserved renal function suggests renovascular disease is likely with a sensitivity and specificity in excess of 90%. In the comparative studies of Elliott and Miralles and colleagues, captopril renography was a more sensitive and specific screening test than the captopril plasma renin activity test. Although there may be confounding variables, such as renal dysfunction, medications, and types of stenosis, a positive captopril renogram may suggest a cure or improvement in blood pressure control with successful intervention such as PTRA or revascularization. Whether captopril renography can predict stabilization of individual kidney function is speculative and deserving of further study.

Evaluation of renovascular hypertension.

Many tests are available for the evaluation of renovascular hypertension; each of these has its own advantages and disadvantages as a screening test. The nonimaging tests include measurement of peripheral plasma renin activity, the captopril test, and renal vein renin sampling, all of which have inherent limitations. Screening tests also are available that provide more information as anatomic or physiologic images. Among the anatomic imaging methods, intravenous urography is the least accurate screening test, although it may provide other useful information. Magnetic resonance angiography may prove to be useful, although its use is limited by its high cost. The gold standard at present for diagnosing renal artery stenosis is contrast angiography, and improvements have been made using digital subtraction technology. However, its invasive nature and high cost do not warrant its routine use as a screening test in the evaluation of renovascular hypertension. Doppler sonography is a physiologic imaging test, and although it is limited because of its operator-dependent nature, it is most useful in the evaluation of patients with renal transplants. Captopril renal scintigraphy is another physiologic imaging test, and it has proven to be an excellent initial screening test that provides both diagnostic and prognostic information.

Suppression of Renal vein Renin Profiles by Mannitol Prophylaxis: Implications in the Evaluation of Renovascular Hypertension

Renal arteriography with concomitant renal vein renin profiling remains the diagnostic standard for evaluating the anatomic and physiologic significance of stenotic renal artery lesions in hypertensive patients. False-negative renal vein renin profiles with failure of lateralization in patients with anatomically apparent high-grade stenosis complicate the diagnostic process. Mannitol is frequently administered prophylactically to minimize the risk of dye nephropathy in these patients. Yet, the potential effects of mannitol on renal vein renin profiling in man have not been previously reported. Seven patients with renovascular hypertension were studied prospectively to determine changes in renal vein renin profiles before and after mannitol prophylaxis. Despite captopril stimulation, all patients demonstrated significant renin suppression leading to the loss of renin lateralization in patients with unilateral renovascular hypertension. In 60% of the patients, renal vein renin ratios fell to below the standard 1.5 to 1 ratio after mannitol infusion. In patients with bilateral renovascular disease, the least stenotic side suppressed completely, while the more stenotic side suppressed partially. Percent suppression analysis showed a mean suppression of 56.8% on the stenotic side versus 8.2% on the noninvolved side (P less than 0.002). In every study, suppression equaled or exceeded 32% on the involved side and was less than this on the noninvolved side. Thus, the degree of renin suppression following mannitol infusion may prove to be an important tool in the diagnosis of clinically significant stenotic lesions. The mechanism of mannitol-induced suppression remains undefined, but appears independent of volume expansions or dilutional effects. The inhibitory effects of mannitol on renin profiles can obscure the diagnosis of underlying renovascular hypertension.

The role and rationale of nuclear medicine procedures in the differential diagnosis of renovascular hypertension

The use of radionuclides in the differential diagnosis of renovascular hypertension has gone through many periods of enthusiasm and of disappointment. Regardless of the problems with the routine renogram, the availability of gamma camera renal evaluation makes possible meaningful preintervention of screening. The use of the test as a follow-up procedure is an extremely important but often overlooked application of radionuclides in the evaluation of renovascular hypertension. The radionuclide technique is a sensitive and accurate method of evaluating the results of percutaneous angioplasty or surgery or renal function in the affected kidney of patients with renovascular disease. A major change in our approach to the nuclear medicine diagnosis of renovascular hypertension has been the introduction of captopril renography. Although there is still a great deal of work to be done and many investigators are actively studying captopril renography, the potential of the test is clear. Captopril renography should include a baseline renogram, followed by the administration of 25 mg of captopril and a repeat study. Specificity and sensitivity data on this test probably will not be available for several years, but preliminary results are encouraging enough to justify routine use at this time in clinics in which screening for renovascular hypertension is carried out.

Low-Dose Captopril Scintigraphy in the Evaluation of Renovascular Hypertension

This study compared the results of renal scintigraphy with simultaneous administration of Tc-99m DTPA and I-131 Hippuran (before and after 25 mg of oral captopril) with the results of the renal arteriogram and renal vein renins (before and after the administration of 25 mg of oral captopril) to evaluate the sensitivity and specificity of renal scintigraphy in the diagnosis of renovascular hypertension. The results of 21 consecutive patients suspected of having renovascular hypertension who underwent scintigraphy and renal arteriography were analyzed. Renal scintigraphy postcaptopril detected all the cases of renovascular hypertension (eight patients) plus two additional patients who had significant renovascular stenosis but no renin overproduction. The results indicate that the renal scintigram, before and after the administration of captopril, is an accurate and sensitive test for the detection of renovascular hypertension and should be used as a screening procedure before arteriography is considered.

Renal Perfusion/Excretion Determination Renogram: A New Tool in the Diagnostic Evaluation of Renovascular Hypertension

Presented herein are initial experiences with the RP/ED renogram, a unique radioisotope differential split function study, which can be performed with a minimum of discomfort to the patient. This test should totally supplant the existing renogram and, with additional experience, may replace the use of split function studies in the evaluation of renovascular hypertension.

Surgical results and the diagnostic evaluation of renovascular hypertension.

Surgical results and the diagnostic evaluation of renovascular hypertension.