Safety of CO(2)- and gadodiamide-enhanced angiography for the evaluation and percutaneous treatment of renal artery stenosis in patients with chronic renal insufficiency

Adverse Events Associated with Intra-Arterial Administration of Gadolinium-Based Contrast Agents: A Systematic Review and Meta-Analysis

PURPOSE

To determine the risk of immediate hypersensitivity reactions (HRs), contrast-associated acute kidney injury (CA-AKI), nephrogenic systemic fibrosis (NSF), and gadolinium retention associated with use of intra-arterial gadolinium-based contrast agents (GBCAs).

MATERIALS AND METHODS

MEDLINE, Embase, and Cochrane Central Register of Controlled Trials were searched from 1988 (GBCAs approved for clinical use) to March 2021 for studies reporting adverse events associated with intra-arterial administration of GBCAs. The number of adverse events and GBCA administrations were used to calculate incidence in individual studies, and results across studies were pooled using random-effects meta-analysis.

RESULTS

There were 72 studies (patients = 1,221) that reported on HR, 59 studies (patients = 1,142) that reported on CA-AKI, and 6 studies (patients = 291) that reported on NSF. No studies reported gadolinium retention as an outcome. Based on 5 events and 1,451 GBCA administrations, the incidence of HR per 100 administrations was 0.95 (95% CI, 0.52-1.51). Based on 90 events and 1,318 GBCA administrations, the incidence of CA-AKI per 100 administrations was 5.94 (95% CI, 3.92-8.34). Based on 7 events and 361 GBCA administrations, the incidence of NSF per 100 Group I GBCA administrations was 4.72 (95% CI, 0.35-13.70). There were no unconfounded NSF events after Group II GBCA administration.

CONCLUSIONS

HRs to intra-arterial administration of GBCAs are rare, with no serious reactions. Limited data demonstrate a higher-than-expected rate of CA-AKI; however, multiple confounding factors were noted. Thus, any causative link of CA-AKI to GBCA remains controversial. Also, severe physiologic reactions (including life-threatening arrhythmias) during coronary angiography have been reported.

Contrast-induced nephropathy in non-cardiac vascular procedures, a narrative review: Part 2

This is Part 2 of a narrative review summarizing the literature on CIN after non-cardiac vascular diagnostic or therapeutic procedures, focusing on peripheral artery disease (PAD) and renal artery stenosis (RAS). Part 1 discussed CIN in relation to aortic aneurysms and carotid stenosis. We comment on the incidence, biomarkers, risk factors, and consequences of CIN in patients with PAD or RAS, as well as on strategies to prevent CIN. Future perspectives in the field of CIN in relation to non-cardiac vascular procedures are also considered.

Negligible Risk of Acute Renal Failure Among Hospitalized Patients After Contrast-Enhanced Imaging With Iodinated Versus Gadolinium-Based Agents

INTRODUCTION

The potential adverse renal outcome among patients undergoing iodine-based contrast-enhanced computerized tomography (CT) has been questioned recently, given the caution undertaken in patients' selection, hydration protocols, and the low radiocontrast volume, used with advanced imaging equipment.

MATERIALS AND METHODS

This study is a retrospective assessment of renal outcome in 12,580 hospitalized patients undergoing contrast-enhanced CT, compared with 754 patients subjected to gadolinium-based magnetic resonance imaging, with subsequent propensity matching for clinical characteristics and potential risk factors.

RESULTS

The risk of postcontrast acute kidney injury (PC-AKI) was found to be negligible as compared with patients undergoing enhanced magnetic resonance imaging studies, before and after propensity matching (8% vs 7.3% rate of AKI in the nonmatched iodine-based contrast agents [IBCAs] and gadolinium-based contrast agents [GBCAs], respectively, P = 0.3, and 7% in the matched IBCA group, P = 0.9), including comparisons among subgroups with well-defined risk factors such as chronic renal failure, diabetes, older age, and hypertension. However, lower systolic blood pressure before imaging was associated with higher risk to develop PC-AKI after IBCA administration but not with GBCA (for systolic blood pressure lower than 110 mm Hg, odds ratio for AKI after IBCA was 1.49; 95% confidence interval, 1.16-1.88, and after GBCA; odds ratio, 0.12; 95% confidence interval, 0.003-0.73).

CONCLUSIONS

With the current precautions undertaken, the real-life risk of PC-AKI among inpatients undergoing CT is insignificant. Possible reasons for the diverse impact of blood pressure on the propensity to develop acute kidney failure after iodine-based but not gadolinium-based enhancement imaging are discussed.

Contrast induced-acute kidney injury following peripheral angiography with carbon dioxide versus iodinated contrast media: A meta-analysis and systematic review of current literature

OBJECTIVE

We conducted a meta-analysis to compare the incidence of acute kidney injury (AKI) with carbon dioxide (CO₂ ) versus iodinated contrast media (ICM).

BACKGROUND

Contrast induced-acute kidney injury (CI-AKI) is a known complication following endovascular procedures with ICM. CO₂ has been employed as an alternative imaging medium as it is nontoxic to the kidneys.

METHODS

Search of indexed databases was performed and 1,732 references were retrieved. Eight studies (7 observational, 1 Randomized Controlled Trial) formed the meta-analysis. Primary outcome was AKI. Fixed effect model was used when possible in addition to analysis of publication bias.

RESULTS

In this meta-analysis, 677 patients underwent 754 peripheral angiographic procedures. Compared with ICM, CO₂ was associated with a decreased incidence of AKI (4.3% vs. 11.1%; OR 0.465, 95% CI: 0.218-0.992; P = 0.048). Subgroup analysis of four studies that included granular data for patients with chronic kidney disease (CKD) did not demonstrate a decreased incidence of AKI with CO₂ (4.1% vs. 10.0%; OR 0.449, 95% CI: 0.165-1.221, P = 0.117). Patients undergoing CO₂ angiography experienced a higher number of nonrenal events including limb/abdominal pain (11 vs. 0; P = 0.001) and nausea/vomiting (9 vs. 1; P = 0.006).

CONCLUSIONS

In comparison to ICM, CO₂ use is associated with a modestly reduced rate of AKI with more frequent adverse nonrenal events. In studies that use CO₂ as the primary imaging agent, the average incidence of AKI remained high at 6.2%-supporting the concept that factors other than renal toxicity from ICM may contribute to renal impairment following peripheral angiography. © 2017 Wiley Periodicals, Inc.

Contrast-Induced Acute Kidney Injury in Patients Undergoing Carotid Artery Stenting: An Underestimated Issue

Carotid artery stenting (CAS) is increasingly offered to patients with carotid artery stenosis. Although CAS is a less invasive (and thus more attractive) alternative compared with carotid endarterectomy, it requires the use of contrast material. A possible side effect from the use of contrast material during CAS is the development of contrast-induced acute kidney injury (CI-AKI). This review discusses the incidence/prevalence and clinical significance of CI-AKI developing after CAS. We also discuss possible measures to reduce the incidence of CI-AKI after CAS.

Use of Gadolinium-Based Angiography for Renal Artery Stenting in a Patient With Renal Insufficiency

The number of percutaneous diagnostic and interventional procedures performed continues to increase. Despite the use of various methods to reduce the incidence of contrast-induced nephropathy, the development of renal failure remains a significant problem with iodinatedbased contrast agents. Patients with a baseline renal insufficiency are at considerably higher risk of permanent renal deterioration following exposure to iodinated contrast. The authors report a successful case of percutaneous stenting of the renal artery using a gadolinium-based contrast agent in a high-risk patient with renal insufficiency.

Renal Artery Stenting Using CO2 Gas Angiography in Combination with Iodinated Contrast Angiography

A 76-year-old woman was hospitalized repeatedly due to unexplained heart failure. On admission, she had hypertensive acute heart failure. Her symptoms disappeared promptly after the initial treatment; however, her systolic blood pressure remained at over 160 mmHg despite her taking three antihypertensive drugs. Closer examination revealed hemodynamically significant right renal artery stenosis and a lack of left kidney function. We performed percutaneous transluminal renal angioplasty using CO2 angiography in combination with iodinated contrast agents. The patient's renal function and blood pressure improved, however, CO2 gas-induced mild ischemic colitis occurred. We discuss the possibility of the use of combined iodinated contrast angiography and CO2 angiography to avoid contrast-induced nephropathy and the complications peculiar to CO2 angiography.

Ultra-low iodine concentrations iso-attenuating with diagnostic 0.5M gadolinium in endovascular procedures to minimize the risk of contrast nephropathy: A phantom study

PURPOSE

To establish the concentrations of iodine contrast media (I-CM) iso-attenuating with 0.5M gadolinium contrast media (Gd-CM), regarded diagnostic in catheter angiography and vascular interventions in azotemic patients, at various X-ray tube potentials with correlation to skin radiation dose.

MATERIALS AND METHOD

20-mL syringes filled with 30, 40, 50, 70 and 90 mgI/mL, 0.5M Gd-CM and air were placed in a water-equivalent phantom and exposed at about 50, 60, 70, 80 and 90 kV in an X-ray angiographic system. Relative contrast between the contrast materials and the background phantom material was measured on a PACS workstation. Radiation entrance dose, measured with a dose meter and estimated from the dose-area-product (DAP), was adjusted for radiation backscatter to simulate absorbed skin dose.

RESULT

The iodine concentrations 30, 40, 50, 70 and 90 mg/mL resulted in the same relative contrast as 0.5M gadolinium at 53, 57, 62, 71 and 85 kVp, respectively. Air had lower relative contrast than all iodine concentrations at all kVp-settings except for 30 mgI/mL above 84 kVp. The measured skin radiation dose was less than 1 mGy per exposure at all kVp-settings, and around 25-30% lower than the dose estimations derived from the angiographic system's in-built DAP meter.

CONCLUSION

Low-kilovoltage X-ray technique and ultra-low concentrations of I-CM iso-attenuating with 0.5M Gd-CM may be utilizable in peripheral arteriography and endovascular interventions, to minimize the total CM-dose to avoid CIN in azotemic patients.

The use of gadolinium for arterial interventions

BACKGROUND

Gadolinium (Gd) has been traditionally used as a non-nephrotoxic alternative to iodinated contrast for digital subtraction angiography (DSA) in patients with chronic renal insufficiency. However, its use has been questioned on the basis of reports of nephrotoxicity and its recent association with nephrogenic systemic fibrosis (NSF), a potentially lethal complication. Recently available data are conflicting with respect to the true safety profile of intra-arterial Gd. The purpose of this study was to examine the risk of contrast nephropathy and NSF after Gd exposure in a large population of azotemic patients undergoing DSA.

METHODS

A comprehensive database encompassing data on all patients who underwent DSA between June 2003 and December 2007 at the New York Presbyterian Hospital was retrospectively reviewed. Patients receiving Gd either alone or in combination with iodinated contrast during DSA were identified and further analyzed. Acute renal failure (ARF) was defined as an elevation in serum creatinine (Cr) by >0.5 mg/dL within 48 hours of exposure. Clinical follow-up was conducted through chart reviewing as well as telephonic interviews with patients and their primary care physicians.

RESULTS

A total of 153 patients underwent 179 exposures to Gd either alone (33%) or in combination (67%) with iodinated contrast. Mean follow-up duration was 27.1 months. The mean Cr level was 1.94 ± 0.78 mg/dL and 1.96 ± 1.1 mg/dL before and after DSA, respectively. There were 20 (11.2%) instances of ARF. The mean Cr level before DSA was higher in patients who developed ARF versus those in the non-ARF group (2.7 ± 1.1 mg/dL vs. 1.9 ± 0.7 mg/dL, p = 0.004). In the ARF group, 12 patients had a return to baseline renal function, four experienced irreversible renal deterioration, and four needed dialysis (4.5% incidence of irreversible renal failure). There were 19 deaths at the time of this study (12.4%). The highest risk for the development of ARF after Gd exposure occurred in patients with Cr levels of >3.0 mg/dL before DSA and in those receiving >0.4 mmol/kg of Gd. For patients who received iodinated contrast in combination with Gd, there was a trend toward a higher risk for developing ARF as compared with those receiving only Gd. Finally, there were no instances of NSF identified in any of the patients who received intra-arterial Gd.

CONCLUSIONS

Although Gd has the potential to cause kidney injury similar to iodinated contrast, the risk of irreversible renal failure and the requirement for dialysis is low. Life- or limb-threatening interventions should not be avoided in this patient cohort because of preexisting elevations in Cr. These data should help guide the use of Gd in patients with chronic renal insufficiency.

Current status of gadolinium toxicity in patients with kidney disease

Gadolinium-based contrast (GBC) agents have recently been the subject of intense interest for physicians across numerous specialties. These agents are widely used as contrast for magnetic resonance imaging and have been generally considered safe. Early on, phase III trials and small studies in low-risk patients suggested a benign renal profile; however, more recent studies raised the possibility of nephrotoxicity, although it is not clear whether it approaches the incidence of nephropathy associated with iodinated radiocontrast. In 2006, reports of a rare systemic fibrosing condition called nephrogenic systemic fibrosis (NSF) were recently linked to exposure of patients with advanced kidney disease to GBC agents. Analysis of the data suggests that certain GBC agents are more likely to be associated with NSF. Also, not all patients with kidney disease are at risk for developing NSF, only those with advanced acute or chronic kidney disease. Avoidance of GBC exposure is the best approach for high-risk patients. When GBC is required to obtain optimal images, use of low dosages of more stable macrocyclic agents is safer and preferred. This article reviews the current status of GBC agents as nephrotoxins and causes of NSF and provides opinions on how to use these agents in patients with underlying kidney disease.

Nephrogenic systemic fibrosis: incidence, associations, and effect of risk factor assessment--report of 33 cases

PURPOSE

To describe the presentation and clinical course of patients with nephrogenic systemic fibrosis (NSF) at a large acute-care hospital, to evaluate the overall incidence of NSF, and to assess the effect of a hospital-wide policy regarding gadolinium-based contrast agent (GBCA) use on NSF incidence.

MATERIALS AND METHODS

A review of all cases of NSF observed at an institution from 2003 to 2008 was conducted. This HIPAA-compliant study was approved by the institutional review board. The informed consent requirement was waived. Demographics, medical history, and associated conditions were recorded. Radiologic procedures were evaluated if they were performed within 1 year prior to NSF onset. GBCA use was assessed by checking the electronic database for each procedure. The incidence of NSF was compared before and after implementation of an institutional policy designed to assess risk of NSF prior to GBCA use.

RESULTS

All 33 patients with NSF (mean age, 49 years; age range, 15-78 years) had advanced renal failure (estimated glomerular filtration rate < 15 mL/min/1.73 m(2)) when the GBCA was injected. Twenty-six patients had severe chronic or end-stage renal disease, and seven had acute renal failure. The mean interval between contrast material injection and NSF onset was 29 days +/- 25 (standard deviation) (range, 4-112 days). The overall incidence of NSF was 36.5 cases per 100,000 gadolinium-enhanced magnetic resonance (MR) examinations between 2003 and 2006 and four cases per 100,000 gadolinium-enhanced MR examinations between 2007 and 2008 after screening for NSF risk was instituted (Fisher exact test, P = .001). Five patients developed NSF in the peritransplant period, and four underwent a catheter-based radiographic procedure with administration of a GBCA.

CONCLUSION

Common associations of GBCA MR imaging and NSF were acute and severe chronic renal failure and liver or renal transplantation. Screening procedures performed before MR imaging to determine which patients were at risk of developing NSF appear to reduce the incidence of this complication and further support the belief that NSF is associated with GBCA administration.

Gadolinium-enhanced angiography for diagnosis and interventional treatment of subclavian artery stenosis prior to fistula creation

We report the use of gadolinium-based contrast agent for both diagnostic and interventional subclavian angiography in two azotemic patients, presenting with an asymptomatic, high-grade stenosis of the left subclavian artery, ipsilateral to the site of choice for native fistula creation. Angiographic imaging performed with diluted gadolinium-based contrast material was clear enough to perform successful subclavian artery stenting, resulting in normalization of the arterial blood pressure in the afferent artery of the dialysis fistula. Clinically, no decrease in residual renal function and no other complication were noted immediately or a longer period after the interventional treatment.

Contrast medium use

Various properties of iodinated contrast media (osmolality, ionic versus nonionic, and viscosity) may contribute to contrast-induced nephropathy (CIN). Therefore, the choice of contrast medium affects the risk for CIN. There is good evidence that low-osmolar contrast media are less nephrotoxic than high-osmolar contrast media in patients at increased risk for CIN who receive intra-arterial iodinated contrast. Current evidence suggests that nonionic isosmolar contrast presents the lowest risk for CIN in patients with chronic kidney disease (CKD), particularly in those patients with diabetes mellitus. Intra-arterial administration of contrast media may be associated with a greater risk for CIN above that observed with intravenous administration. The use of gadolinium or CO(2) as alternative contrast media to avoid the risk of nephrotoxicity cannot be substantiated by clinical trials and therefore cannot be recommended. Most studies show that, within a class, higher volumes (>100 mL) of iodinated contrast medium are associated with a higher risk for CIN. However, in patients at high risk, such as those with CKD and diabetes, even small volumes of contrast medium can have adverse effects on renal function.

Prevention of Contrast Media–induced Nephrotoxicity after Angiographic Procedures

Contrast medium-induced nephrotoxicity (ie, contrast nephrotoxicity [CN]) remains an important complication of angiographic procedures. If administration of iodinated contrast medium is deemed necessary in patients at high risk of CN, volume expansion should be offered and the lowest possible dose of nonionic isosmolar dimeric or nonionic low-osmolar monomeric contrast medium should be used. Prophylactic administration of fenoldopam or acetylcysteine has not offered consistent protection against CN. Intravenous acetylcysteine could be considered in emergency situations. Recently, sodium bicarbonate infusion has been shown to reduce the risk of CN. Hemofiltration for several hours before and after contrast medium injection may offer good protection against CN in patients with advanced renal disease. Prophylactic hemodialysis does not offer any protection against CN.

Gadolinium contrast media are more nephrotoxic than a low osmolar iodine medium employing doses with equal X-ray attenuation in renal arteriography: an experimental study in pigs

RATIONALE AND OBJECTIVES

To investigate in a unilaterally nephrectomized porcine model whether gadolinium contrast media (Gd-CM) are less nephrotoxic than iodine media (I-CM) in x-ray arteriography of a kidney made temporarily ischemic by arterial balloon occlusion.

MATERIALS AND METHODS

In a noncrossover design, 3 mL of each test solution were injected in eight pigs (mean weight 19 kg) at a rate of 20 mL/min into the right renal artery at the start of a 10-minute period of ischemia. In group 1 (40 pigs) we injected 0.5 M gadopentetate, 0.5 M gadodiamide, 0.5 M iohexol (190 mg I/mL), 0.18 M iohexol (70 mg I/mL; with an x-ray attenuation equal to that of 0.5 M Gd-CM at 80 kV), and saline. In group 2 (24 pigs), we tested 0.18 M iohexol with ischemia and saline with and without ischemia. Gd- and iodine contrast media functioned as markers of glomerular filtration rate (GFR). When saline was tested, a low dose of iohexol (3 mL per pig; 300 mg I/mL) was injected as GFR marker intravenously in group 1 and into the renal artery in group 2. The plasma half-life elimination times of the CM 1-3 hours after injection were used to compare the effects of the different test solutions on GFR. Longer half-life means lower GFR.

RESULTS

Group 1: median plasma half-life elimination time of the GFR marker was 3 340 minutes after injection of 0.5 M gadopentetate, 256 after 0.5 M gadodiamide, 179 after 0.5 M iohexol, 143 after 0.18 M iohexol, and 133 minutes after saline. All differences except that between 0.18 M iohexol and saline were statistically significant (P < .01). Group 2: median plasma half-life was 174 minutes after 0.18 M iohexol with ischemia, 196 minutes after saline with ischemia, and 195 minutes after saline without ischemia. There were no significant differences between the test solutions in group 2 (P > .05).

CONCLUSION

In pigs, 0.5 M Gd-CM were more nephrotoxic than both equal-attenuating (70 mg I/mL) and equimolar (190 mg I/mL) concentrations of the I-CM iohexol. These results do not support the "off-label" use of Gd-CM for renal x-ray arteriography in man instead of commercially available concentrations of iodine contrast media at 140, 150 and 180 mg I/mL or diluted to 70 mg I/mL.

Value, limitations, and techniques of renal artery stenting

Percutaneous therapy for renovascular occlusive disease has become the preferred alternative to open renal artery revascularization. Angioplasty and stenting of renal artery stenoses has been shown to be a safe and effective option for severe hypertension and ischemic nephropathy. Catheter-based treatment, especially when performed with lower-profile systems can be performed with minimal morbidity and a reliably high degree of initial technical success. The long-term beneficial effects on blood pressure control and renal function, while debated, appear to be valid. In this article, data supporting the value and limitations of renal artery stenting are reviewed, and our technique for renal artery stenting using a lower-profile platform of balloons and stents is described.

Gadolinium, carbon dioxide, and iodinated contrast material for planning inferior vena cava filter placement: a prospective trial

PURPOSE

To prospectively compare the diagnostic accuracy of CO(2) and gadolinium to iodinated contrast material for inferior vena cavography before inferior vena cava (IVC) filter placement.

MATERIALS AND METHODS

Forty patients underwent injection of iodinated contrast material, CO(2), and gadolinium. Iodinated contrast material was used as the standard. Caval diameter was determined with calibrated software. Three readers blinded to contrast agent used measured the distance from the superior image border to the inferior margin of the renal veins and from the inferior image border to the iliac bifurcation. The measurements with CO(2) and gadolinium were compared to those with iodinated contrast material to obtain the interobserver and intraobserver variability. The presence or absence of caval thrombus and variant anatomy was noted. The same readers reexamined 12 studies in a separate session to determine intraobserver variability and correlation.

RESULTS

Caval diameter differed by 0.4 mm or less for all three agents. Measurements with all agents were within 2 mm of each other for all patients. Gadolinium and CO(2) were not significantly different from one another in measuring caval diameter. At the initial reading, compared with iodinated contrast material, gadolinium had greater mean interobserver error in measuring the distance to the iliac bifurcation and both renal veins (range, 1.6-1.8 mm) than CO(2) (range, 0.2-1.4 mm). This finding, although statistically significant for gadolinium (P <.05), was of doubtful clinical relevance. Interobserver correlation was significantly worse for CO(2) at the levels of the iliac bifurcation (P =.02) and right renal vein (P =.008). Interobserver correlation for gadolinium was similar to that for iodinated contrast material at all levels. At repeat reading, there was significantly inferior intraobserver correlation with use of CO(2) for both renal veins (P <.05) compared to iodinated contrast material and for the left renal vein (P <.05) compared to gadolinium. Gadolinium identified three of three renal vein anomalies identified with iodinated contrast material whereas CO(2) localized one of three.

CONCLUSION

CO(2) and gadolinium had limitations when compared with iodinated contrast material. Gadolinium provided superior consistency in identifying relevant landmarks for filter placement. CO(2) demonstrated significantly greater mean correlative error than gadolinium at initial and repeat readings.

Value of MR angiography before percutaneous transluminal renal artery angioplasty and stent placement

PURPOSE

To determine the benefit of preprocedural three-dimensional gadolinium (Gd)-enhanced magnetic resonance (MR) angiography before percutaneous transluminal renal artery angioplasty and stent placement (PTRA/S) in terms of procedural success, iodinated contrast material load, and procedure duration.

MATERIALS AND METHODS

Over an 18-month period, 39 patients underwent attempted percutaneous renal angioplasty with or without stent placement. A total of 48 renal arteries were treated (40 cases of atherosclerosis, one of stent restenosis, five of fibromuscular dysplasia, and two of transplant stenosis). Preprocedural Gd-enhanced MR angiography was available in 16 procedures (41%). Procedural outcome, complications, iodinated contrast material load, number of diagnostic angiographic runs, and total procedure duration were each compared between two subgroups: patients who had preprocedural Gd-enhanced MR angiography ("prior MR angiography group") and those who did not ("no MR angiography" group).

RESULTS

All procedures were technically successful. The two groups were equivalent in terms of age and disease pattern. However, technical complexity of the procedure was judged to be high in five of 16 procedures in the prior MR angiography group compared to three of 23 procedures in the no MR angiography group (P =.16). Bilateral or dual interventions were performed in six of 16 procedures in the prior MR angiography group compared to three of 23 in the no MR angiography group (P =.075). Iodinated contrast material load was significantly lower in the prior MR angiography group than in the no MR angiography group (68.7 mL +/- 28.4 vs 119.1 mL +/- 49.2 mL;P <.0008). The number of diagnostic angiographic runs before interventions were also significantly lower in the prior MR angiography group (1.2 +/- 0.4 vs 2.6 +/- 0.7; P <.0001). Overall procedure duration was comparable between the two groups (91.9 +/- 47.8 vs 112.2 +/- 49.4;P =.2).

CONCLUSION

Preprocedural planning with use of Gd-enhanced MR angiography significantly reduces the iodinated contrast material requirement during percutaneous renal artery interventions. It can also significantly shorten procedure duration.

Magnetic resonance angiography for the diagnosis of renal artery stenosis: a meta-analysis

AIM

To review the published literature comparing the diagnostic accuracy of magnetic resonance angiography (MRA) with and without gadolinium in diagnosing renal artery stenosis, using catheter angiography as reference.

MATERIALS AND METHODS

A meta-analysis was performed of English language articles identified by computer search using PubMed/MEDLINE, followed by extensive bibliography review from 1985 to May 2001. Inclusion criteria were: (1) blinded comparison with catheter angiography; (2)indication for MRA stated; (3) clear descriptions of imaging techniques; and (4) interval between MRA and catheter angiography < 3 months and only the largest of all studies from one centre was selected in the analysis.

RESULTS

A total of 39 studies were identified, of which 25 met the inclusion criteria. The number of patients included in the meta-analysis was 998: 499 with non-enhanced MRA and 499 with gadolinium-enhanced MRA. The sensitivity and specificity of non-enhanced MRA were 94% (95% CI: 90-97%) and 85% (95% CI: 82-87%), respectively. For gadolinium-enhanced MRA sensitivity was 97% (95% CI: 93-98%) and specificity was 93% (95% CI: 91-95%). Thus, specificity and positive predictive value were significantly better for gadolinium-enhanced MRA (P < 0.001). Accessory renal arteries were depicted better by gadolinium-enhanced MRA (82%; 95% CI: 75-87%) than non-gadolinium MRA (49%; 95% CI: 42-60%) (P < 0.001).

CONCLUSIONS

Gadolinium-enhanced MRA may replace arteriography in most patients with suspected renal artery stenosis, and has major advantages in that it is non-invasive, avoids ionizing radiation and uses a non-nephrotoxic contrast agent.