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Multiple renal arteries and non-contrast magnetic resonance angiography in transplant renal artery stenosis.

Munoz Mendoza J, Melcher ML, Daniel B, Tan JC - Clin Kidney J (2012)

View Article: PubMed Central - PubMed

Affiliation: Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, FL, USA.

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The reported incidence of transplant renal artery stenosis (TRAS), as high as 23% in earlier decades, ranges between 1.2 and 3.9% in more recent reports... TRAS is a frequent cause of refractory hypertension and allograft dysfunction, but it is often treatable with percutaneous angioplasty... A renal allograft biopsy revealed mild acute tubulointerstitial cellular rejection... After treatment with steroids, sCr decreased to 2.2 mg/dL and blood pressure improved... The patient was continued on aspirin and clopidogrel was started... The sCr decreased to 1.8 mg/dL and his blood pressure improved... Other useful tests for diagnosis of renal artery stenosis are the computed tomographic angiography (sensitivity 98% and specificity 94%) and the magnetic resonance angiography (sensitivity 83% and specificity 97%)... The majority of studies have shown impressively high technical success, improvement in blood pressure and renal function and reduction in the number of anti-hypertensive drugs... However, studies reporting outcomes after angioplasty for the management of TRAS have found divergent results... Some studies reported worse graft survival in patients with TRAS after angioplasty compared with controls, others found no difference in graft survival between patients treated with or without angioplasty, and more recently, Ghazanfar et al. reported better long-term graft survival in patients with TRAS treated with percutaneous angioplasty alone or with stent placement compared with medical treatment (86 versus 63%, respectively)... Failure to consistently detect a benefit in outcomes from angioplasty contrasts with the excellent reports improving serum creatinine and blood pressure... These conflicting results may be related to the expertise and experience of the interventionists and perhaps because many interventions are performed in clinically non-significant stenosis... However, the possibility of TRAS must always be entertained when worsening hypertension and acute allograft dysfunction are present. (ii) The presence of multiple renal arteries in the appropriate clinical scenario may be a simple useful clue for the diagnosis of TRAS. (iii) Because the risks of worsening renal dysfunction and nephrogenic systemic fibrosis with exogenous contrast agents, the use of inversion-recovery-prepared balanced steady-state free precession non-contrast magnetic resonance angiography may be advisable.

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(A) Non-contrast magnetic resonance angiography using inversion-recovery-prepared balanced steady-state free precession technique (INHANCE®) and (B) CO2 angiogram showing narrowing of the renal artery (black arrows) with mild post-stenotic dilatation.
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fig1: (A) Non-contrast magnetic resonance angiography using inversion-recovery-prepared balanced steady-state free precession technique (INHANCE®) and (B) CO2 angiogram showing narrowing of the renal artery (black arrows) with mild post-stenotic dilatation.

Mentions: A 44-year-old Asian man with end-stage renal disease of unknown cause underwent renal transplantation from a deceased donor. The renal allograft had a main superior renal artery and an accessory inferior renal artery. He received immunosuppression with thymoglobulin, tacrolimus, mycophenolate mofetil and prednisone. His sCr decreased from 4.7 mg/dL pre-operatively to 2.0 mg/dL throughout the first month. Approximately 4 months post-transplantation, he had an episode of acute allograft dysfunction—sCr increased to 3.8 mg/dL—associated with increased blood pressure requiring an additional anti-hypertensive drug. On physical exam, no bruit was detected overlying the allograft. A CDU demonstrated a 10.5 cm renal allograft with normal echogenicity and two patent main renal arteries both with normal velocities. Evaluation of the intra-renal segmental arteries showed ‘parvus tardus’ waveforms but normal resistive index. A renal allograft biopsy revealed mild acute tubulointerstitial cellular rejection. After treatment with steroids, sCr decreased to 2.2 mg/dL and blood pressure improved. Five months post-transplantation, his blood pressure worsened and sCr rose up to 2.9 mg/dL. A second renal allograft CDU of the superior-pole intra-renal segmental arteries showed parvus tardus waveforms and low-normal resistive index (0.47–0.50). Angle-corrected peak velocities in the main superior renal artery were normal, from 73 to 85 cm/s. The inferior pole resistive index was normal (0.61) without parvus tardus waveform and the corresponding inferior accessory renal artery peak systolic velocity was not elevated (28 cm/s). A kidney allograft biopsy showed patchy mild interstitial inflammation associated with areas of atrophy, but no evidence of segmental or global glomerulosclerosis, glomerulitis, proliferation, necrosis or crescents. Focal intimal sclerosis was observed in the interlobular arteries and mild to moderate arteriolosclerosis was present. A non-contrast magnetic resonance angiography was performed using inversion-recovery pulses to enhance arterial inflow and three-dimensional balanced steady-state free precession acquisition (INHANCE®) [6, 7]. This imaging study showed focal narrowing of the superior main renal artery 2 cm distal to the anastomosis with mild post-stenotic dilatation (Figure 1A). The inferior accessory artery was grossly normal, but assessment was limited by the small caliber of this vessel. X-ray angiography with CO2 confirmed a 15 mm-long stenosis, 8 mm distal to the anastomosis in the superior main renal artery (Figure 1B). The peak systolic gradient of 100 mmHg was consistent with a very tight stenosis. Angioplasty was performed with excellent angiographic results and no residual pressure gradient. A decision was made not to use a stent due to the difficulty of deployment in the area of stenosis. The inferior accessory artery was normal. A post-angioplasty renal allograft CDU showed improved arterial waveforms and resistive index. The patient was continued on aspirin and clopidogrel was started. The sCr decreased to 1.8 mg/dL and his blood pressure improved. He is currently maintained on low doses of blood pressure medications.


Multiple renal arteries and non-contrast magnetic resonance angiography in transplant renal artery stenosis.

Munoz Mendoza J, Melcher ML, Daniel B, Tan JC - Clin Kidney J (2012)

(A) Non-contrast magnetic resonance angiography using inversion-recovery-prepared balanced steady-state free precession technique (INHANCE®) and (B) CO2 angiogram showing narrowing of the renal artery (black arrows) with mild post-stenotic dilatation.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC4400505&req=5

fig1: (A) Non-contrast magnetic resonance angiography using inversion-recovery-prepared balanced steady-state free precession technique (INHANCE®) and (B) CO2 angiogram showing narrowing of the renal artery (black arrows) with mild post-stenotic dilatation.
Mentions: A 44-year-old Asian man with end-stage renal disease of unknown cause underwent renal transplantation from a deceased donor. The renal allograft had a main superior renal artery and an accessory inferior renal artery. He received immunosuppression with thymoglobulin, tacrolimus, mycophenolate mofetil and prednisone. His sCr decreased from 4.7 mg/dL pre-operatively to 2.0 mg/dL throughout the first month. Approximately 4 months post-transplantation, he had an episode of acute allograft dysfunction—sCr increased to 3.8 mg/dL—associated with increased blood pressure requiring an additional anti-hypertensive drug. On physical exam, no bruit was detected overlying the allograft. A CDU demonstrated a 10.5 cm renal allograft with normal echogenicity and two patent main renal arteries both with normal velocities. Evaluation of the intra-renal segmental arteries showed ‘parvus tardus’ waveforms but normal resistive index. A renal allograft biopsy revealed mild acute tubulointerstitial cellular rejection. After treatment with steroids, sCr decreased to 2.2 mg/dL and blood pressure improved. Five months post-transplantation, his blood pressure worsened and sCr rose up to 2.9 mg/dL. A second renal allograft CDU of the superior-pole intra-renal segmental arteries showed parvus tardus waveforms and low-normal resistive index (0.47–0.50). Angle-corrected peak velocities in the main superior renal artery were normal, from 73 to 85 cm/s. The inferior pole resistive index was normal (0.61) without parvus tardus waveform and the corresponding inferior accessory renal artery peak systolic velocity was not elevated (28 cm/s). A kidney allograft biopsy showed patchy mild interstitial inflammation associated with areas of atrophy, but no evidence of segmental or global glomerulosclerosis, glomerulitis, proliferation, necrosis or crescents. Focal intimal sclerosis was observed in the interlobular arteries and mild to moderate arteriolosclerosis was present. A non-contrast magnetic resonance angiography was performed using inversion-recovery pulses to enhance arterial inflow and three-dimensional balanced steady-state free precession acquisition (INHANCE®) [6, 7]. This imaging study showed focal narrowing of the superior main renal artery 2 cm distal to the anastomosis with mild post-stenotic dilatation (Figure 1A). The inferior accessory artery was grossly normal, but assessment was limited by the small caliber of this vessel. X-ray angiography with CO2 confirmed a 15 mm-long stenosis, 8 mm distal to the anastomosis in the superior main renal artery (Figure 1B). The peak systolic gradient of 100 mmHg was consistent with a very tight stenosis. Angioplasty was performed with excellent angiographic results and no residual pressure gradient. A decision was made not to use a stent due to the difficulty of deployment in the area of stenosis. The inferior accessory artery was normal. A post-angioplasty renal allograft CDU showed improved arterial waveforms and resistive index. The patient was continued on aspirin and clopidogrel was started. The sCr decreased to 1.8 mg/dL and his blood pressure improved. He is currently maintained on low doses of blood pressure medications.

View Article: PubMed Central - PubMed

Affiliation: Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, FL, USA.

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

The reported incidence of transplant renal artery stenosis (TRAS), as high as 23% in earlier decades, ranges between 1.2 and 3.9% in more recent reports... TRAS is a frequent cause of refractory hypertension and allograft dysfunction, but it is often treatable with percutaneous angioplasty... A renal allograft biopsy revealed mild acute tubulointerstitial cellular rejection... After treatment with steroids, sCr decreased to 2.2 mg/dL and blood pressure improved... The patient was continued on aspirin and clopidogrel was started... The sCr decreased to 1.8 mg/dL and his blood pressure improved... Other useful tests for diagnosis of renal artery stenosis are the computed tomographic angiography (sensitivity 98% and specificity 94%) and the magnetic resonance angiography (sensitivity 83% and specificity 97%)... The majority of studies have shown impressively high technical success, improvement in blood pressure and renal function and reduction in the number of anti-hypertensive drugs... However, studies reporting outcomes after angioplasty for the management of TRAS have found divergent results... Some studies reported worse graft survival in patients with TRAS after angioplasty compared with controls, others found no difference in graft survival between patients treated with or without angioplasty, and more recently, Ghazanfar et al. reported better long-term graft survival in patients with TRAS treated with percutaneous angioplasty alone or with stent placement compared with medical treatment (86 versus 63%, respectively)... Failure to consistently detect a benefit in outcomes from angioplasty contrasts with the excellent reports improving serum creatinine and blood pressure... These conflicting results may be related to the expertise and experience of the interventionists and perhaps because many interventions are performed in clinically non-significant stenosis... However, the possibility of TRAS must always be entertained when worsening hypertension and acute allograft dysfunction are present. (ii) The presence of multiple renal arteries in the appropriate clinical scenario may be a simple useful clue for the diagnosis of TRAS. (iii) Because the risks of worsening renal dysfunction and nephrogenic systemic fibrosis with exogenous contrast agents, the use of inversion-recovery-prepared balanced steady-state free precession non-contrast magnetic resonance angiography may be advisable.

No MeSH data available.


Related in: MedlinePlus