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Vascular and Interventional Radiology |
1 From the Departments of Radiology (E.N., J.M.L., R.K.K., M.W.W., R.L.G.) and Surgery (R.H., J.S.M.), University of California, San Francisco, 505 Parnassus Ave, San Francisco, CA 94143-0628. From the 1998 RSNA scientific assembly. Received November 20, 1998; revision requested January 11, 1999; final revision received June 18; accepted July 21. Address reprint requests to J.M.L.
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Abstract |
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 TOP Abstract IntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
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MATERIALS AND METHODS: The records of 716 potential living renal donors who underwent conventional arteriography were reviewed. Abnormal arteriograms were reexamined to characterize vascular disease, and the effect of identifying renovascular disease on subsequent donor surgery was ascertained with chart review.
RESULTS: Renovascular abnormalities were noted in the dictated reports in 78 patients (10.9%). The most common causes were fibromuscular dysplasia and atherosclerosis. The arteriograms of 64 patients were available for retrospective review. Abnormalities were characterized as minimal stenosis (<30% narrowing) in 42 patients and mild stenosis (30%–50% narrowing) in 19 of 61 patients with arteriographic abnormalities at retrospective review. In three patients, no significant abnormality was seen at retrospective review. The effect of detecting renovascular disease on donor selection was determined in 74 of the 78 patients. In 73 of these 74 patients (99%), detection of an abnormality directly affected donor surgery.
CONCLUSION: In this population of potential renal donors, the arteriographic incidence of renovascular disease (10.9%) was higher than previously reported. Although renovascular abnormalities were mild, their detection influenced the plan for donor surgery in almost all patients.
Index terms: Aneurysm, renal, 961.73 • Kidney, transplantation, 961.4551 • Renal angiography, 81.1243, 961.1222 • Renal arteries, fibrodysplasia, 961.7224 • Renal arteries, stenosis or obstruction, 961.721
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Introduction |
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TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
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Transplantation surgeons have traditionally relied on conventional arteriography, which is highly accurate for defining anatomy and excluding disease of the renal arteries, for making the clinical decision of whether to accept a prospective renal donor. Authors of recent studies have investigated the use of noninvasive modalities such as helical computed tomographic (CT) arteriography (11–13) and gadolinium-enhanced magnetic resonance (MR) arteriography (14) for the preoperative examination of potential renal donors. These authors have shown that CT arteriography and MR arteriography are as accurate as conventional arteriography for assessing the number and location of the renal arteries.
However, the accuracy of the noninvasive modalities in the diagnosis of unsuspected intrinsic renal arterial disease, which is one of the central roles of arteriography, to our knowledge has not been established. Moreover, the effect of detected renal arterial disease on patient selection has not been established clearly and may vary among transplantation centers.
The purpose of this study was to determine the arteriographic incidence and severity of intrinsic renal arterial disease in potential renal donors and to evaluate the effect of identifying renovascular abnormalities on subsequent donor surgery.
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MATERIALS AND METHODS |
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TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
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The dictated reports of 716 consecutive patients' arteriographic examinations performed in living potential renal donors at our institution during 10 years from April 1988 to March 1998 were reviewed. The number of renal arteries in each of the 716 patients was tabulated, and 78 patients with renovascular disease noted in the dictated report were identified.
Sixty-four of the 78 abnormal arteriograms were available for retrospective review; however, the other 14 studies were unavailable because the images were purged from our archives as a result of 5 or more years of inactivity of the patients' files. The 64 available arteriograms were reviewed retrospectively by an experienced arteriographer (J.M.L.), who was blinded to the dictated report. The reviewer was asked to identify the morphology, location, severity, and likely cause of all detected renal arterial lesions.
The severity of renal arterial stenosis was graded by using the following categories: minor mural irregularity and/or minimal stenosis, defined as less than 30% narrowing; mild stenosis, defined as 30%–50% narrowing; moderate stenosis, defined as 51%–70% narrowing; and severe stenosis, defined as greater than 70% narrowing. Intra- or extrarenal aneurysms also were noted.
Renal arterial lesions exhibiting characteristic circumferential, "beaded" mural irregularity with or without associated stenosis or aneurysm formation were assigned the likely cause of fibromuscular dysplasia. Lesions with eccentric mural irregularity or stenosis in patients of advanced age and evidence of atherosclerotic abnormalities in other visualized vessels were termed atherosclerotic disease. Extrinsic compression by the median arcuate ligament of the diaphragm was diagnosed when an indentation was identified in a characteristic location on the cephalic surface of the proximal part of the renal artery and when the degree of stenosis varied with the phase of respiration. In all other instances, the likely cause was said to be indeterminate.
The clinical records of patients with abnormal arteriograms were reviewed by a member of the transplantation surgery team (R.H.) to determine the effect of arteriographic findings on subsequent donor surgery. Specific notes with regard to the effect of arteriographic findings on donor selection were available in the clinical records of 74 of 78 patients.
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RESULTS |
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TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
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Intrinsic renovascular abnormalities were identified in the initial arteriographic report in 78 patients (10.9%). Of the patients with renal arterial abnormalities, 50 were women (64%) and 28 were men (36%), with an age range of 24–78 years (mean age, 49.3 years).
Renovascular abnormalities were noted to be unilateral in 51 patients (65%) and bilateral in 27 patients (35%). In the patients with unilateral lesions, the abnormalities were in the right renal arteries in 38 of 51 patients (75%) and were in the left renal arteries in 13 of 51 patients (25%).
Fibromuscular dysplasia was reported to be the likely cause of renovascular abnormality in 47 of 716 patients (6.6%); atherosclerosis, in 12 patients (1.7%); and extrinsic compression by the median arcuate ligament of the diaphragm, in one patient (0.1%). In 18 patients (2.5%), either the likely cause was not mentioned in the initial report or the appearance of the vascular abnormality was thought not to be specific enough to allow the assignment of a likely cause. In four patients (0.6%), all of whom had a beaded appearance of their renal arteries characteristic of fibromuscular dysplasia, single or multiple aneurysms of the extra- or intrarenal arteries were detected.
Multiple renal arteries were identified arteriographically in 289 patients (40.4%). Multiple renal arteries were unilateral in 226 patients (31.6%) (on the right in 99 patients; on the left in 127 patients) and were bilateral in 63 patients (8.8%).
Of the 1,432 kidneys imaged on the 716 arteriograms, 352 kidneys (24.6%) had multiple renal arteries.
Retrospective Review
The arteriograms of 64 of the 78 patients (82%) with reported renal arterial abnormalities were available for retrospective review. The retrospective interpretation agreed with the findings in the dictated report in 61 of 64 patients (95%). The arteriographic abnormality noted in the dictated reports in three of 64 patients (5%) was not evident on retrospective review. We speculate that the original positive interpretations of these three patients' arteriograms may have been based on the evaluation of dynamic images available at the time of the study and on the absence of this information on the static images used for retrospective review.
In 42 of 61 patients with arteriographic abnormalities noted at retrospective review, the morphology of the abnormality was characterized as minor mural irregularity and/or minimal stenosis (<30% narrowing). Mild stenosis (30%–50% narrowing) was evident in 19 of 61 patients. There were no patients with moderate to severe stenosis or with occlusion of the renal arteries. Aneurysms were seen in association with mild areas of stenosis in four patients.
A likely cause of renal arterial disease was assigned by using criteria outlined in Materials and Methods; however, the assignment of a specific cause in patients with only minimal renal arterial abnormalities often was difficult. Fibromuscular dysplasia was assigned retrospectively as the likely cause in 41 of 61 patients; atherosclerosis, in 14 patients; extrinsic compression by the median arcuate ligament of the diaphragm, in two patients; and the cause was thought to be indeterminate in four patients.
The severity of lesions thought to represent fibromuscular dysplasia ranged from mild circumferential mural irregularity (Fig 1) to a beaded appearance with aneurysm formation (Fig 2). Lesions thought to represent atherosclerotic disease spanned the spectrum from minimal eccentric irregularity of the vessel wall to mild luminal stenosis, with a 45% reduction in luminal diameter being the greatest degree of stenosis identified (Fig 3).
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Effect of Arteriography on Donor Selection
The effect of arteriography on the selection of patients for donor nephrectomy was determined explicitly from the medical record in 74 of the 78 patients in whom renovascular disease was detected at arteriography. In four patients (all of whom did not undergo donor nephrectomy), information regarding the influence of arteriographic abnormalities on the selection for donor nephrectomy was not available in the patient records.
Thirty-five of the 74 patients (47%) in whom the effect of arteriography on donor selection status could be determined with their medical records were excluded from donation on the basis of the abnormal arteriogram. Thirty-nine of 74 (53%) were considered suitable candidates for donor nephrectomy despite the presence of an arteriographic abnormality. The kidney selection for planned nephrectomy was determined directly with the arteriogram in 38 of 39 patients (97%). In one patient (3%), kidney selection was not affected by the detection of an arteriographic abnormality. Thus, the arteriographic detection of a renal arterial abnormality influenced surgical planning in 73 of 74 patients (99%).
Of the 35 patients excluded from donation, 24 patients had bilateral arteriographic abnormalities and 11 patients had unilateral abnormalities. The arteriograms of 21 of the 24 patients with bilateral arteriographic abnormalities were available for retrospective review and showed minor mural irregularity and/or minimal stenosis (<30% narrowing) in 17 patients and mild stenosis (30%–50% narrowing) in four patients. The arteriograms of 10 of the 11 patients with unilateral arteriographic abnormalities were available for retrospective review and showed mural irregularity without stenosis in eight patients and mild stenosis in two patients.
Of the 39 patients who were considered suitable candidates despite renovascular abnormalities, 29 patients underwent donor nephrectomy. The right kidney was harvested in 23 patients, and the left kidney was harvested in six patients. Arteriographic abnormalities were unilateral in all patients accepted for donor nephrectomy, and the kidney ipsilateral to the arteriographic abnormality was harvested in 28 of the 29 patients. In one of the 29 patients, the arteriographic abnormality was thought to be not clinically important by the transplantation team, and the contralateral kidney was harvested secondary to technical considerations related to the multiplicity of renal arteries in the donor. The arteriograms of 18 of the 29 patients who underwent nephrectomy were available for retrospective review and revealed minor mural irregularity and/or minimal stenosis (<30% narrowing) in 14 patients and mild stenosis (30%–50% narrowing) in four patients.
Ten of the 39 patients cleared initially by the transplantation team did not undergo donor nephrectomy for reasons unrelated to the arteriographic findings. In all of these patients, a plan for nephrectomy had been formulated and the ipsilateral kidney had been selected. The reasons for not performing nephrectomy in these patients included recipient medical disease or death, recipient receipt of a cadaveric kidney, donor refusal to undergo nephrectomy, and donor medical disease not discovered at outpatient examination (the donor had lung cancer or interstitial lung disease at chest radiography at admission, the donor was actively drinking alcohol, or the donor had hypertension or abnormally low 24-hour creatinine clearance discovered during admission for arteriography).
Findings at Surgery
Donor nephrectomy was performed successfully in all patients in whom it was attempted, and no unexpected findings were discovered at surgery. Of particular interest, one patient with arteriographically suspected extrinsic compression of the right renal artery by the median arcuate ligament of the diaphragm (Fig 4) underwent donor nephrectomy. Selection of the right kidney for harvesting was made on the basis of the arteriographic findings. Extrinsic compression of the right renal artery by the median arcuate ligament was confirmed at surgery.
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DISCUSSION |
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TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
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An explanation for our high incidence of recognized vascular disease may be our correspondingly low diagnostic threshold for interpreting renovascular abnormality. At our institution, the contour of the renal arteries is scrutinized closely during the arteriographic procedure, and even minimal abnormalities are reported. The transplantation surgeons at our institution believe that the arteriographic detection of subtle renovascular abnormalities is essential in the clinical decision-making process of donor selection. As a result, the threshold used at our institution for diagnosing a renovascular abnormality may be lower than that used in other renal transplant centers.
Indeed, a majority of abnormalities detected in our series were of minimal to mild severity. Two-thirds of the abnormalities were characterized by only mild mural irregularity and/or minimal stenosis (<30% narrowing), and the remainder of the stenoses were mild (
50% narrowing). The greatest degree of luminal stenosis was 45%. Whether our low threshold for interpreting an abnormality on donor arteriograms is justified is uncertain. Cragg et al (15) have reported previously that mild to moderate fibromuscular dysplasia discovered incidentally during a renal donor examination increases that donor's risk of developing hypertension fourfold compared with the risk in the general population, whether or not the prospective donor eventually underwent nephrectomy.
To our knowledge, no researchers in prior studies have examined the effect of varying arteriographic sensitivity on the clinical outcome for renal donors or recipients. However, we now know that the diagnosis of a minimal or mild renal vascular abnormality at our institution has a definite effect on donor selection.
Guidelines for donor selection and for kidney selection in an individual patient may vary among institutions; however, to our knowledge several general rules are applied commonly. Patients with bilateral renal arterial disease are not acceptable donor candidates. In prospective donors with minimal or mild unilateral disease, the kidney ipsilateral to the vascular abnormality may be harvested if a more suitable donor cannot be identified (6,8). In potential donors without vascular disease and with single renal arteries, harvesting of the left kidney is usually preferred because of its longer renal vein. In female donors of childbearing age, the right kidney is preferred for donation because the left kidney is usually spared from hydronephrosis due to pregnancy (7).
In our series, the arteriographic detection of a renal arterial abnormality influenced surgical planning in 73 of 74 patients. Almost half our patients with arteriographic renal arterial abnormalities were eliminated from consideration because of that arteriographic finding. Most of these patients had bilateral disease. All patients deemed suitable candidates despite a renal arterial abnormality had unilateral disease; in these cases, the affected kidney was almost always the kidney selected for harvesting.
Authors of recent literature have advocated the use of noninvasive modalities such as helical CT arteriography (11–13) and gadolinium-enhanced MR arteriography (14) for the preoperative screening examination of potential renal donors. These authors have established the accuracy of the noninvasive modalities for defining the number and length of renal arteries and for detecting high-grade renal arterial stenosis (
70% narrowing) in patients suspected to have renovascular hypertension (16).
However, the sensitivity of these modalities for mild intrinsic renal arterial abnormalities, as may be seen in potential donors, is yet undetermined. In a study by Rubin et al (11) of a series of 12 potential renal donors, no intrinsic renal arterial abnormalities were detected with either helical CT arteriography or conventional arteriography. Using helical CT arteriography, Platt et al (12), in one of a series of 32 renal donor candidates, were able to prospectively diagnose mild renal arterial stenosis (30%–50% narrowing) that was confirmed with subsequent conventional arteriography. However, in Platt et al's series, helical CT arteriography failed to help detect a case of mild fibromuscular dysplasia later depicted with conventional arteriography.
In the largest series to our knowledge to date in which helical CT arteriography was used for the examination of prospective renal donors (N = 57), Cochran et al (13) reported on only one patient with an intrinsic renal arterial abnormality. None of the 10 prospective renal donors in a series by Bakker et al (14) showed renal arterial abnormalities at either gadolinium-enhanced MR arteriography or conventional arteriography. Furthermore, in Bakker et al's series, stenosis could not be excluded in four small accessory renal arteries "owing to inadequate spatial resolution" of MR arteriography.
In the majority of patients in our series, arteriographic detection of renovascular abnormalities of minimal to mild severity influenced the decision to accept patients as renal donors and influenced the selection of the kidney to be harvested in those patients ultimately chosen as donors. At the present time, further study is needed to determine if noninvasive modalities such as helical CT arteriography and gadolinium-enhanced MR arteriography are sufficiently sensitive to provide the information regarding intrinsic renal arterial abnormalities required by transplantation surgeons. The effect of screening donors with noninvasive modalities, as compared with screening with conventional arteriography, on the long-term clinical outcome of both renal donors and recipients needs to be studied in the future. Until the results of such studies are available, conventional arteriography seems to be the prudent choice for the preoperative evaluation of prospective renal donors.
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Footnotes |
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References |
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TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
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This article has been cited by other articles:
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  A. Holden, A. Smith, P. Dukes, H. Pilmore, and M. Yasutomi Assessment of 100 Live Potential Renal Donors for Laparoscopic Nephrectomy with Multi-Detector Row Helical CT Radiology, December 1, 2005; 237(3): 973 - 980. [Abstract] [Full Text] [PDF]
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 V. D. Garovic and S. C. Textor Renovascular Hypertension and Ischemic Nephropathy Circulation, August 30, 2005; 112(9): 1362 - 1374. [Full Text] [PDF]
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 M. C. J. M. Kock, J. N. M. Ijzermans, K. Visser, S. M. Hussain, W. Weimar, P. M. T. Pattynama, G. P. Krestin, and M. G. M. Hunink Contrast-Enhanced MR Angiography and Digital Subtraction Angiography in Living Renal Donors: Diagnostic Agreement, Impact on Decision Making, and Costs Am. J. Roentgenol., August 1, 2005; 185(2): 448 - 456. [Abstract] [Full Text] [PDF]
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 H. H. Wolters, T. Vowinkel, M. Schult, S. Heidenreich, N. Senninger, and K.-H. Dietl Fibromuscular dysplasia in a living donor: early post-operative allograft artery stenosis with successful venous interposition Nephrol. Dial. Transplant., January 1, 2002; 17(1): 153 - 155. [Full Text] [PDF]
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S. C. Rankin, W. Jan, and C. G. Koffman Noninvasive Imaging of Living Related Kidney Donors: Evaluation with CT Angiography and Gadolinium-Enhanced MR Angiography Am. J. Roentgenol., August 1, 2001; 177(2): 349 - 355. [Abstract] [Full Text] [PDF]
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