Screening Test For Renal Artery Stenosis Research Articles

Doppler ultrasound and renal artery stenosis: An overview

Renovascular disease is a complex disorder, most commonly caused by fibromuscular dysplasia and atherosclerotic diseases. It can be found in one of three forms: asymptomatic renal artery stenosis (RAS), renovascular hypertension, and ischemic nephropathy. Particularly, the atherosclerotic form is a progressive disease that may lead to gradual and silent loss of renal function. Thus, early diagnosis of RAS is an important clinical objective since interventional therapy may improve or cure hypertension and preserve renal function. Screening for RAS is indicated in suspected renovascular hypertension or ischemic nephropathy, in order to identify patients in whom an endoluminal or surgical revascularization is advisable. Screening tests for RAS have improved considerably over the last decade. While captopril renography was widely used in the past, Doppler ultrasound (US) of the renal arteries (RAs), angio-CT, or magnetic resonance angiography (MRA) have replaced other modalities and they are now considered the screening tests of choice. An arteriogram is rarely needed for diagnostic purposes only. Color-Doppler US (CDUS) is a noninvasive, repeatable, relatively inexpensive diagnostic procedure which can accurately screen for renovascular diseases if performed by an expert. Moreover, the evaluation of the resistive index (RI) at Doppler US may be very useful in RAS affected patients for predicting the response to revascularization. However, when a discrepancy exists between clinical data and the results of Doppler US, additional tests are mandatory.

Catheter-Based Therapy for Atherosclerotic Renal Artery Stenosis

Atherosclerotic renal artery stenosis (RAS) is more common than has been previously appreciated1,2 and is an independent predictor of death regardless of the presence, severity, or method of revascularization of coronary artery disease.3–5 Among 1235 patients undergoing diagnostic coronary angiography, multivariate analysis demonstrated that RAS (>50%) was a stronger independent predictor of all-cause mortality (relative risk [RR], 2.9; 95% confidence interval [CI], 1.7 to 7.0) than congestive heart failure (RR, 2.3; 95% CI, 1.3 to 4.1), elevated left ventricular ejection fraction (RR, 1.7; 95% CI, 1.2 to 2.2), or decreased renal function (serum creatinine) (RR, 1.3; 95% CI, 1.1 to 1.5).3 A subsequent expansion of that study group, extended to 3987 patients undergoing abdominal aortography at the time of diagnostic cardiac catheterization, identified an incremental effect of the severity of RAS on the 4-year mortality rates. They found that a mild-to-moderate (50%) RAS was associated with a 30% 4-year mortality rate, which almost doubled (52%) with severe (>95%) RAS.4 The cause-and-effect relation between RAS and death is uncertain. It is possible that the presence of RAS is simply a marker for more diffuse or extensive atherosclerosis, which would result in more vascular-related deaths. However, there is one study5 that raises the possibility that the treatment of RAS with a renal stent in patients with renal insufficiency can improve mortality rates. In this trial, patients who improved their renal function after renal stent placement had significantly better survival rates compared with those whose renal function did not improve. A dedicated educational effort aimed at improving the diagnosis and treatment of peripheral arterial disease, including RAS, has been supported over the past 10 years by several professional societies.6–8 There is now objective evidence from the Medicare database that this effort to increase the number of patients …