Surgical management of renovascular hypertension

Ex vivo renal repair: technical tips, when, and why

Ex vivo renal artery repair combined with cold perfusion protection is an operative technique for managing complex renal artery lesions. Most diseases of the renal artery are proximal, and typically treated either medically, by endovascular means, or surgically. When surgery of the main renal artery is required, it can typically be performed with warm renal ischemia times of <30 minutes. However, in more distal disease, which can involve the segmental branches, a much more complicated surgical reconstruction can be anticipated. This often will necessitate warm ischemia times of >45 minutes, and can lead to direct renal nephron damage. In this setting, the ex vivo technique with cold perfusion can allow for lengthy reconstructive times of several hours without any measurable harm to renal function. The technique can be performed with low morbidity and mortality, an excellent rate of renal salvage, and preservation of renal function.

Results of the major randomized clinical trials of renal stenting and implications for future treatment strategies

The management of atherosclerotic renovascular disease remains an area of controversy. This review details the results of major clinical trials and their implications for contemporary treatment recommendations for affected patients.

Influence and critique of the ASTRAL and CORAL Trials

Optimal management of renal artery atherosclerotic occlusive disease has been widely debated and studied. Although the accepted invasive treatment has evolved into favoring balloon angioplasty and stenting, the indications for intervention or medical therapy have not been universally agreed upon. The Angioplasty and Stenting for Renal Artery Lesions (ASTRAL) trial was conducted to answer the question of whether medical therapy or angioplasty and stenting is the best treatment for hemodynamically significant renal artery stenosis. However, the ASTRAL trial's study design was faulty and therefore did not provide conclusive evidence to answer the question. The Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) trial was designed to answer the same question as to which treatment (medical or angioplasty and stent) is best for renal artery stenosis, and its methodologies took into consideration the weaknesses of the ASTRAL trial. Results are soon to be released.

Renovascular hypertension

This article discusses the pathophysiologic features, diagnosis, treatment, and management of patients with renovascular hypertension. Timely diagnosis is important as the disease can carry a more serious prognosis than essential hypertension and is less amenable to drug treatment. Renovascular hypertension also carries a greater risk of progression to accelerated or malignant hypertension and may result in irreversible ischemic failure of the affected kidney. Various treatments are available including medical management, angioplasty and/or stenting, and revascularization. Regardless of treatment approach, nursing care is an integral part of the patient's management, especially continuing follow-up of blood pressure.

The use of colorflow duplex scanning to detect significant renal artery stenosis

The purpose of this study was to review our institutional experience with colorflow duplex scanning in detecting significant renal artery stenosis and to validate the criteria used: renal artery peak systolic velocity (PSV) >/=200 cm/sec and renal-to-aortic peak systolic ratio (RAR) >/=3.5. The results of renal artery duplex and arteriography in 58 patients (107 kidneys) who underwent both exams were reviewed. Arteriography revealed 32 main renal arteries with >/=60% stenosis. The PSV criterion detected 29, for a sensitivity of 91%, specificity of 75%, positive predictive value (PPV) of 60%, negative predictive value (NPV) of 95%, and accuracy of 79%. Using RAR >/=3.5 provided a sensitivity of 72%, specificity of 92%, PPV of 79%, NPV of 88%, and accuracy of 86%. In a subset of 36 kidneys that had hilar scans, the criteria of acceleration time (AT) >/=100 cm/sec and index (AI) </=3.78 kHz/sec were evaluated. The AT and AI yielded sensitivity of 50% and 36%, specificity of 86% and 100%, PPV of 70% and 100%, NPV of 73% and 71%, and accuracy of 72% and 75%, respectively. Colorflow duplex scanning is clinically useful in screening for hemodynamically significant renal artery stenosis. The renal artery PSV criterion is highly sensitive, with a high NPV that obviates the need for arteriography in most cases of a negative duplex. The criteria of RAR, AT, and AI are of less value.

Atherosclerotic renal artery stenosis: from diagnosis to treatment

Renovascular hypertension represents a form of correctable hypertension and preventable renal failure. Such patients need to be identified early so that specific therapy can be instigated. Patient identification requires a high index of suspicion in patients with certain clinical features. Subsequent non-invasive imaging may result in angiography which is required for diagnostic purposes and for planning intervention. Correctable therapy takes one of two forms, namely percutaneous transluminal renal angioplasty, with or without stenting, or surgical revascularisation, together with modification of underlying risk factors.