Upper extremity access for renal artery stenting: radial, brachial and axillary access: how to do them safely and pitfalls to avoid.

This manuscript traces the history of changes in preferred upper extremity puncture sites for renal artery stenting as our understanding of anatomy, techniques, technology and pharmacology, each separately and their confluence, has improved. A very detailed description of each technique is beyond the scope of this review; the references should allow the reader to readily access this information.

Ostial renal artery stent placement in patients 75 years of age or older.

Renal artery stent placement has been shown to improve blood pressure (BP) and stabilize renal function in patients with atherosclerotic renovascular disease. However, limited data are available in patients > or = 75 years of age. We analyzed the prestent characteristics and clinical outcomes of patients aged > or = 75 years who underwent renal artery stenting at our institution. We compared these data with those from the remainder of our stent cohort. Nineteen of 89 (21.3%) stent patients were > or = 75 years old. Before intervention, those > or = 75 years were significantly more likely to be women (84.2% v 55%; P = .02), current or former smokers (78.6% v 36.8%; P = .002), and on a greater number of antihypertensive medications (3.68 v 2.80; P = .048). Average clinical follow-up was similar in both groups (23.9 v 23.2 months; P > .05). At last available follow-up, there were more deaths in those > or = 75 years (7/19 v 5/70; P = .038). No significant difference was found in the incidence of dialysis after intervention (3/19 v 7/70). Seventy-four percent of those > or = 75 years had improved BP, 21% were stable, and 5% were worse. Renal function was improved in 26%, stable in 53%, and worse in 21%. Among those > or = 75 years, there was a significant decrease in systolic BP (186.9 to 144.4; P < .01). There was a trend toward decreased diastolic BP and medications. These clinical results did not differ significantly from patients <75 years. Patients > or = 75 years of age with atherosclerotic renovascular disease have a higher incidence of mortality 2 years after renal artery stent placement, but they seem to derive clinical benefit comparable to younger patients.

Treatment of atheroembolization with corticosteroids.

Aortic atheroembolization is a feared complication of invasive procedures such as arteriography, often leading to devastating complications including renal insufficiency. To date, even in cases with evolving renal failure, there is no recommended treatment. This case report describes the successful treatment with corticosteroids of a patient with deteriorating renal function after renal arteriography and angioplasty, resulting in rapid and sustained improvement in renal function. The implications of this observation are discussed.

Transcatheter interventions for the treatment of peripheral atherosclerotic lesions: part I.

Transcatheter endovascular procedures are increasingly used to treat symptomatic peripheral atherosclerosis. This two-part review identifies the existing evidence supportive of the application of transcatheter treatments for peripheral atherosclerotic lesions. The first part addresses the treatment of obstructive lesions that cause limb claudication and critical ischemia, renovascular hypertension and azotemia, and mesenteric ischemia. Studies were identified via a search of MEDLINE (January 1993 through April 1999) and reference lists of identified articles. When multicenter prospective randomized trials or other high-quality studies were unavailable, a preference was given to studies with at least 50 patients per treated group and a minimum mean follow-up duration of 6 months. Data presented in tables are proportionally weighted averages from included studies. For each application, the authors assessed the quality of evidence (QOE; efficacy, safety, and, where available, cost-effectiveness) and made recommendations with appropriate caveats. There is higher QOE supporting the more established treatments such as lower limb percutaneous transluminal angioplasty (PTA) with stent placement and thrombolysis. Treatments such as renal artery PTA and stent placement and mesenteric and brachiocephalic PTA are in wide use, but high QOE supporting general application is lacking. Blanket recommendations based on established efficacy and cost-effectiveness cannot be made. However, the use of transcatheter therapies can be supported in specific circumstances based on an expected reduction in procedure-related morbidity and/or mortality rates. It is hoped that the identification of deficiencies in the literature will inform and inspire critically needed research in this area.

Type B aortic dissection complicating renal artery angioplasty and stent placement.

Percutaneous renal artery stent placement has been demonstrated to improve blood pressure control and stabilize renal function in patients with atherosclerotic renal artery disease. However, this procedure is not without risk of significant morbidity, and its effectiveness, as compared to alternative treatments, has not been adequately established. The authors report a case of acute type B aortic dissection complicating renal artery stent placement. The authors postulate that an intimal disruption occurred during initial balloon angioplasty, and that repeated application of radial, shear, and torque forces during stent placement may have extended the injury. The diagnosis of acute aortic dissection should be considered in patients with suggestive symptoms immediately after stent placement.

Prevention of recurrent pulmonary edema in patients with bilateral renovascular disease through renal artery stent placement.

Pulmonary edema and congestive heart failure (both referred to here as PE) have been reported to be complications of bilateral renal artery stenosis or unilateral stenosis in a solitary functioning kidney (both referred to as BRAS). The goals of this study were to determine whether a history of PE was more common in patients with BRAS than in those with unilateral stenosis and a normal contralateral kidney (URAS), and whether recurrent PE could be prevented by renal artery stent placement. We evaluated 90 consecutive patients with renovascular disease who were treated with percutaneous renal artery stent placement. History and clinical follow-up were obtained through chart review and phone contact with referring physicians. Mean follow-up was 18.4 months after stent placement. Twenty-three of 56 (41%) subjects with BRAS had a history of PE before revascularization, compared with four of 34 (12%) subjects with URAS (P = .05). Twenty-five of the 27 patients with history of PE had adequate clinical follow-up. Seventeen of the 22 (77%) subjects with BRAS and history of PE had no further PE after stent placement in one or both renal arteries. The five BRAS subjects with recurrent PE after stent placement had evidence of stent thrombosis or restenosis. In contrast, only one of three (33%) URAS subjects with a history of PE remained free of PE after stent placement. We conclude that PE is a common complication of BRAS, but not of URAS. In patients with BRAS, recurrent PE can be prevented by successful stent placement in one or both renal arteries.

Fluoroscopic landmarks for optimal visualization of the proximal renal arteries.

PURPOSE: To accurately determine the in vivo orientation of the origin of the renal arteries from the aorta relative to a fluoroscopic bony landmark for optimal diagnostic arteriography and renal artery stent placement. MATERIALS AND METHODS: One hundred sixty abdominal computed tomography (CT) scans of patients in eight age groups (20-90 years) were reviewed to determine the angle of the origins of the renal arteries from the aorta relative to the long axis of the L-1 spinous process (L1SP). RESULTS: The right renal artery arises ventrally at an angle of 30 degrees (standard deviation [SD] = 15 degrees) from a plane orthogonal to the long axis of the L1SP. The left renal artery arises dorsally at an angle of 7 degrees (SD = 13 degrees) relative to the same plane. CONCLUSIONS: The optimal initial angle for angiographic evaluation of the origin of the renal artery and for renal artery stent placement is 30 degrees left anterior oblique (LAO) relative to the L1SP for the right renal artery and 7 degrees LAO for the left renal artery. Unfortunately, there is variability in the angle of the renal artery origins from the aorta which cannot be controlled for using this technique. In some patients, additional views will be necessary to optimally depict the origins of the renal arteries.

Comparison of two-dimensional MR digital subtraction angiography of the lower extremity with x-ray angiography.

PURPOSE: To perform a preliminary evaluation of the diagnostic accuracy of contrast-enhanced, two-dimensional (2D) magnetic resonance (MR) digital subtraction angiography (DSA) of the lower extremity by comparison with x-ray angiography (XRA). MATERIALS AND METHODS: Forty lower extremities in 22 patients were imaged at multiple levels with both XRA and 2D MR DSA. Images were retrospectively analyzed by three radiologists in a randomized blinded manner. Seventeen vascular segments were graded as an insignificant lesion, a significant lesion, or as an occlusion. With the use of segments well depicted with XRA as the gold standard, the sensitivity, specificity, and accuracy of 2D MR DSA, as compared with XRA, were evaluated. The McNemar-Stuart-Maxwell test was performed to determine the significance of any differences found. RESULTS: Three hundred eighty-three arterial segments were evaluated with both techniques. Three hundred one segments were well depicted with XRA. There was no significant difference between 2D MR DSA and XRA for assessing the degree of occlusive disease in these 301 segments (.25 < P < .5). The sensitivity, specificity, and diagnostic accuracy of 2D MR DSA were found to be 90%, 98%, and 93%, respectively. CONCLUSION: Two-dimensional MR DSA is an accurate method for assessing arterial lesions in the lower extremity.

In vitro evaluation of the relative thrombolytic efficiency of forced intrathrombic injections: saline versus urokinase.

PURPOSE: To compare the rates of thrombolysis produced by forced intrathrombic injections of saline versus urokinase, as well as automated versus manual injections of urokinase, with use of an in vitro model of a vascular occlusion. MATERIALS AND METHODS: The rates of thrombolysis produced by forced intrathrombic injections of saline and urokinase were compared in an in vitro radiometric model utilizing I-125-labeled thrombus. Similar experiments were performed to compare manual and automated injections of urokinase. The dissolution of the thrombus was quantitatively monitored with use of a scintillation detector. Averaged time activity data for each type of experiment were fit to exponential functions and half times of lysis calculated. The differences in the half times for the experiments being compared were evaluated for significance with use of the Student t test. RESULTS: The half times of lysis produced by forced intrathrombic injections of urokinase were substantially and significantly shorter than those produced by forced saline injections. The half time of lysis produced by automated injections was not significantly different than that produced by manual injections. CONCLUSIONS: Forced intrathrombic injections of urokinase produce faster and substantially more thrombolysis when compared with similarly administered saline. Also, for forced intrathrombic injections of lytic agents, an automated injector is an equivalent alternative to manual injections.

Bolus-chase MR digital subtraction angiography in the lower extremity.

A bolus-chase magnetic resonance (MR) angiographic technique performed with a prototypic stepping table and coil holder and a 15-20-mL injection of contrast material was developed to depict the entire lower extremity. Image acquisition was synchronized with passage of the contrast medium bolus through the lower extremity. Ten subjects underwent the examination, which was performed in less than 1 minute. All major arteries were well demonstrated in all cases.

Retained nephrostomy thread providing a nidus for atypical renal calcification.

Percutaneous nephrostomy (PCN) is a commonly performed procedure. The indications have expanded from merely providing emergency decompression of obstruction to being the initial step of many interventional procedures including percutaneous nephrolithotomy, ureteral stenting dilation and biopsy. Nephrostomy tube design has evolved from a simple trocar to the current self-retaining loop catheters. These catheters contain a suture which, when secured, locks the loop of the catheter in order to prevent accidental removal of the catheter. We present a case where incomplete removal of the locking suture providing the nidus for calcification within the renal pelvis.

Erroneous pressure measurement due to artificially deformed vessel during angioplasty.

Percutaneous transluminal angioplasty is a commonly performed procedure. The clinical success of such a procedure is determined by the combination of the post-procedure angiographic appearance and the pressure gradient across the lesion. This case demonstrates the importance of recognizing the anatomical variation if proper pressure measurements are to be obtained.

Renal vascular disease as a cause of hypertension.

In spite of our comprehensive understanding of renovascular hypertension, diagnostic tests based on the pathophysiology of the disease have been disappointing in their sensitivity and specificity. They are particularly unreliable in the setting of bilateral disease and renal dysfunction. The recent results of vascular surgery and renal angioplasty combined with the use of metallic stents have shown dramatic benefits in revascularization even in the setting of renal artery occlusion, ostial renal artery stenosis, and renal dysfunction. Timely diagnosis and intervention are imperative, and, therefore, we recommend the early use of arteriography using digital subtraction angiographic techniques for the definitive diagnosis.

Diagnosis and treatment of primary hyperaldosteronism.

OBJECTIVE: To characterize the clinical and laboratory features of primary aldosteronism and to evaluate which diagnostic tests can discriminate surgically curable forms of this syndrome. DESIGN: Retrospective analysis of the following data from 82 patients with primary aldosteronism: blood pressure, serum electrolytes, urinary aldosterone and electrolytes, computed tomographic scans, plasma renin and aldosterone before and during upright posture, atrial natriuretic peptide, and adrenal vein aldosterone and cortisol. Clinical outcomes assessed after treatment included blood pressure, serum electrolytes, and plasma renin activity. RESULTS: Drug therapy was discontinued before diagnostic tests were done in 56 of 82 patients (34 with adenomas and 22 with hyperplasia). Compared with patients with hyperplasia, those with adenomas had higher systolic (184 mm Hg and 161 mm Hg, respectively; P < 0.001) and diastolic blood pressures (112 mm Hg and 105 mm Hg; P = 0.03), lower serum potassium levels (3.0 mmol/L and 3.5 mmol/L; P < 0.001), and higher serum CO2 (P = 0.001), atrial natriuretic peptide (P = 0.008), and urinary 18-methyl oxygenated cortisol metabolite levels (P = 0.02). In patients with adenomas, aldosterone secretion lateralized to one adrenal gland and did not increase during the postural stimulation test; preoperative urinary aldosterone levels were correlated with diastolic pressures (r = 0.58; P = 0.001). Hypertension was "cured" postoperatively in approximately 35% of patients with adenomas and those with hyperplasia (P > 0.2) but was "improved" more frequently in those with adenomas (P = 0.002). Cured patients from both groups were younger than those not cured (mean ages, 43 years and 54 years, respectively; P = 0.002) and had lower preoperative mean plasma renin activity (0.17 ng/mL per hour and 0.50 ng/mL per hour; P < 0.001). All patients with adenomas in whom aldosterone secretion lateralized were either cured or improved. CONCLUSION: Of the 51 patients with primary aldosteronism who had adrenalectomy (43 patients with adenomas and 8 with hyperplasia), those most likely to be cured were younger and had lower plasma renin activity. In patients with adenomas who were cured or improved, aldosterone secretion was more likely to lateralize. Tests that distinguished adenomas from adrenal hyperplasia included the postural stimulation test, urinary excretion rates of 18-oxocortisol and 18-hydroxycortisol, and adrenal vein sampling.

Retrograde approach for contralateral iliac and infrainguinal percutaneous transluminal angioplasty: experience in 100 patients.

To assess the technical feasibility of percutaneous transluminal angioplasty (PTA) performed by means of a retrograde contralateral approach, 201 PTA procedures performed from January 1989 to August 1990 were retrospectively reviewed. In 100 of these cases, the retrograde femoral artery puncture employed for acquisition of the initial diagnostic arteriogram was also used for angioplasty of 173 contralateral arteries. The overall technical success rate for PTA via the contralateral route was 91% (157 of 173 arteries). Overall success for contralateral suprainguinal disease was 94% (61 of 65) and was as follows for infrainguinal disease: femoral, 88% (68 of 77); popliteal, 90% (18 of 20); graft anastomoses, 100% (five of five); and infrapopliteal, 83% (five of six). There were eight procedure-related complications, including one clinically insignificant distal atheroembolization, two sheared balloon fragments, three arterial thromboses, and two postprocedural amputations. There were no puncture-related complications. PTA can be performed with a contralateral retrograde femoral puncture in a high percentage of patients, even when disease is well below the inguinal ligament.