1 Section of Nephrology, Medical Department, 2 Surgical Department and 3 Department of Radiology, The National Hospital, Oslo, Norway
Correspondence and offprint requests to: Dr Carl Erik Halvorsen, Section of Nephrology, Medical Department, National Hospital, N-0027 Oslo, Norway.
Keywords: artery occlusion; kidney transplant; magnetic resonance imaging; percutaneous transluminal angioplasty
Introduction
The occurrence of renal transplant artery stenosis has been reported to vary from 1 to 12% in earlier reports [16]. Transplant artery stenosis is usually suspected from an increase in blood pressure, oedema formation and eventually a rise in serum creatinine without any sign of acute rejection [1,6,7]. Doppler sonography may be a valuable tool in establishing the diagnosis [810]. In most centres, intra-arterial angiography is used for confirmation of the diagnosis. Percutaneous transluminal angioplasty (PTA) has for many years been the standard treatment of such lesions with a high success rate, in both the short and long term [13,5,6]. Successful treatment of an occluded transplant artery has not been reported previously, although a case of severe obstructive intrarenal arterial thrombosis was treated successfully with PTA and fibrinolysis back 1982 [11]. We report here the re-opening of a totally occluded renal allograft artery by PTA with salvage of graft function.
Case
A 58-year-old man with a history of chronic glomerulonephritis pre-emptively received a cadaveric kidney transplant mismatched for 0 HLA-DR antigens and two HLA-AB antigens. The renal artery was anastomosed end-to-side to the external iliacal artery. The transplant was functional immediately and serum creatinine stabilized at 170 µmol/l after a few days. On day 20 after transplantation, a rise in serum creatinine to 220 µmol/l prompted anti-rejection treatment, and a biopsy on day 2 of rejection treatment showed Banff borderline rejection changes. Serum creatinine returned to pre-treatment values following treatment with methylprednisolone 1.3 g.
After transplantation, the patient was treated for hypertension. Despite triple combination therapy with atenolol, doxazosin and amlodipine, blood pressure recordings were still in the range of 180/100 mmHg. On day 95 after transplantation, the serum creatinine rose from 155 µmol/l to 210 µmol/l, and anti-rejection therapy was again started with boluses of methylprednisolone. Ultrasound examinations did not show any sign of urinary tract obstruction. A biopsy taken on day 100 post-transplantation revealed acute rejection changes Banff Ia, but a duplex sonography performed at the same time as the biopsy showed increased blood flow velocity (>2 m/s) in the transplant artery distal to the anastomosis. To avoid X-ray contrast infusion during the acute rejection episode, a magnetic resonance image (MRI) was first performed. This clearly demonstrated a significant stenosis (Figure 1) as suspected by duplex Doppler examination. After 6 days of rejection treatment without reversal of the serum creatinine values, an elective intra-arterial angiography was performed and a simultaneous baloon angioplasty was prepared for. The catheter was inserted into the femoral artery on the right side, contralateral to the transplant. Surprisingly, the transplant artery was totally occluded before the area was manipulated by the catheter (Figure 2A
). There was no circulation or uptake of contrast in the parenchyma, and no contrast was seen in the urinary tract or in the bladder.
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Discussion
To our knowledge, this is the first published experience with a successful re-opening of an occluded renal transplant artery by angioplasty. By contrast, large series of elective PTA have been published from different centres including our own [1,3,5,6]. Acute PTA is performed increasingly in coronary heart disease to re-open acute coronary artery occlusions in an effort to minimize infarction [12]. The exact time of the occlusion of the transplant in this case cannot be ascertained, but the brisk diuresis of the patient until the last few hours before the procedure indicates that the occlusion had occurred very recently. Obviously a recently transplanted kidney, as in this case, could not have developed significant collateral circulation and thus the transplant is critically dependent on the blood flow supplied through the renal transplant artery. It is therefore plausible that in this case the transplant was occluded only minutes, or perhaps an hour, before reopening. Alternatively, a marginal blood flow through a subtotal stenosis may have kept the transplant viable for a somewhat longer time; this was probably the case in a previous report of PTA of an intrarenal thrombotic lesion [11]. A warm anoxia (ischaemia) of more than an hour is not likely to be followed by salvage of renal function. In this case, renal function deteriorated after the procedure but this might be due, at least in part, to the iohexol load of 150 ml (300 mg/ml) during the procedure. Loss of renal function is often seen following renal angiography [13,14]. However, the temporary decline in renal function in this patient was probably due to both ischaemia and contrast toxicity in the ischaemic kidney. The final outcome of the procedure was remarkable, with a normalized renal transplant function within a week. This case confirms that transplant artery stenosis may be revealed by duplex Doppler and further demonstrated by MRI. More importantly, however, the occluded artery could be re-opened and the renal transplant rescued. Obviously angioplasty should preferably be performed prior to occlusion.
References