Pediatr Radiol (2004) 34: 432–434 DOI 10.1007/s00247-003-1094-3
Sheldon Wiebe Christian J. Kellenberger Antoine Khoury Stephen F. Miller
Received: 18 August 2003 Revised: 18 September 2003 Accepted: 2 October 2003 Published online: 17 December 2003 Ó Springer-Verlag 2003
S. Wiebe Æ C.-J. Kellenberger A. Khoury Æ S.-F. Miller (&) The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada E-mail:
[email protected] Tel.: +1-416-8135171 Fax: +1-416-8137591
CASE REPORT
Early Doppler changes in a renal transplant patient secondary to abdominal compartment syndrome
Abstract Physiologic changes in renal transplant patients, such as transiently low central venous pressure, may be related to increased intra-abdominal pressure, from the volume of the transplanted kidney itself. Using intraoperative and postoperative Doppler ultrasound of the transplant renal vessels, we identified changes in flow dynamics following closure of the abdomen and reversal of the changes when the abdomen was reopened. This was attributed to abdominal
Introduction Abdominal compartment syndrome and the effects on renal function have been described in clinical and experimental studies [1, 2, 3]. Normally the intraabdominal pressure is equal to the atmospheric pressure (0 mmHg) or less. Intra-abdominal compartment syndrome can develop if there is an acute and rapid rise in the abdominal pressure. Cardiovascular effects include reduced cardiac output and decreased stroke volume from increased systemic vascular resistance (pressure on capillary bed), reduced venous return (compression of subdiaphragmatic veins) and an increased intrathoracic pressure from elevation of the diaphragm. The effect of increased pressure on the kidneys [2] when intraabdominal pressures of 15–20 mmHg are reached is a decrease in renal plasma flow, with resultant glomerular filtration rates down to as little as 25% of normal values. At pressures greater than 20 mmHg, anuria can occur. Renal transplantation, especially in children, is not often considered as a cause of abdominal compartment syndrome. This case illustrates intraoperative Doppler
compartment syndrome and a fasciotomy was created in the abdominal wall to accommodate the transplanted kidney. The findings in this case, in keeping with abdominal compartment syndrome, are not often considered in transplant recipients, but may explain some of the postsurgical physiology in some patients, particularly in the pediatric population. Keywords Renal transplant Æ Abdominal compartment syndrome
changes of compartment syndrome complicating renal transplantation.
Case report A girl aged 2 years and 6 months who had chronic renal failure due to congenital nephrotic syndrome and required peritoneal dialysis underwent renal transplantation (kidney donation by father—transplanted within 30 min). The transplanted kidney was just under 12 cm in length, but because of the size of the child and prior peritoneal dialysis, the relatively large size of the kidney was not felt to be problematic. The native kidneys were small and not removed. Immediate postoperative ultrasound identified the allograft kidney in the right lower quadrant of the abdomen and demonstrated reversal of diastolic flow within interlobar and segmental renal arteries, with preserved venous flow. Because the patient was anuric, approximately 1 h later, sonography was repeated which demonstrated absence of venous flow in the intrarenal veins and at the renal hilum. This was thought to be highly suggestive of renal vein thrombosis and the patient was then returned to the operating room. Intraoperative Doppler ultrasound scanning then demonstrated adequate intrarenal arterial and venous blood flow, with arterial resistive indices measuring between 0.66 and 0.75. The renal vein was shown to be patent without thrombus. Repeat scanning
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following closure of the fascia and skin initially showed no diastolic flow within the intrarenal arteries (resistive index, RI, =1). A few minutes later, reversal of diastolic flow became evident in the intrarenal arteries. Venous flow within intrarenal veins and the main renal vein at the hilum were preserved. Additionally, during intraoperative scanning, the patient was placed in a Trendelenburg position, which demonstrated less reversal of diastolic flow in the renal arteries, representing improved perfusion. At this time, the diagnosis of abdominal compartment syndrome was considered. A permanent fasciotomy was performed to decrease the pressure around the transplanted kidney, and the skin was closed. Diastolic blood flow reappeared in the intrarenal arteries, albeit with slightly elevated resistive indices (RI= 0.85–1.0). Approximately 1 h later, there was improved perfusion, with adequate intrarenal arterial blood flow, slightly lower resistive indices (RI=0.78–0.85), and easier detection of venous flow.
Fig. 1a–d Transplant renal Doppler ultrasound findings. a Transplant renal Doppler ultrasound showing reversal of diastolic blood flow within the segmental renal artery on the initial postoperative study. b Intraoperative Doppler ultrasound a few hours later (while the fascia and skin were open—second operation) shows good intrarenal arterial and venous blood flow. Resistive index ranged from 0.66 to 0.75. c Intraoperative Doppler ultrasound once the fascia and skin were closed shows loss of the diastolic arterial blood flow and within 10 min, reversal of diastolic segmental arterial blood flow. d Postoperative Doppler ultrasound (following fasciotomy) demonstrates normalization of the segmental arterial Doppler flow pattern
The following day (1 day after transplantation), there was adequate arterial and venous flow within the renal parenchyma and the resistive indices had normalized (RI=0.65–0.77). Furthermore, urinary output was normal (Fig. 1).
Discussion This case seems to support the concept that renal transplantation, perhaps even more likely in children than adults, may produce an abdominal compartment syndrome that can cause decreased renal perfusion and subsequently decreased renal function. Most cases of documented abdominal compartment syndrome are related to trauma, ascites, pancreatitis, or abdominal tumors [4, 5]. Renal transplantation will inherently cause some increased intra-abdominal pressure, but the significance may be underestimated. Ferris et al. [1] describe a decrease in central venous pressure in adult post-renal transplant patients that cannot be explained by hemodynamic analysis nor can it be corrected by vigorous fluid resuscitation. The unexplained drop in central venous pressure in post-renal transplant patients may in fact be explained by abdominal compartment syndrome caused by the transplanted kidney itself. It may be that some degree of intra-abdominal compartment syndrome occurs in these patients and because
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there does not seem to be an effect on the incidence of acute tubular necrosis, this may have been under-recognized. The decreased renal function that can occur in some of these patients does not seem to be directly related to the decreased cardiac output as previously thought [2]. It appears that the effect of increased intra-abdominal pressure on the renal cortex alone is not responsible for the negative effect on renal function [3], and it is more likely that the transmission of increased pressure to the renal veins causes a renal outflow obstruction, thereby increasing the renal vascular resistance. This increased vascular resistance is further enhanced by the increased pressure on the abdominal and renal arteries.
For radiologists interpreting transplant kidney ultrasound, reversal of diastolic flow in the intrarenal arteries or absence of flow in the renal veins may be a sign of intra-abdominal compartment syndrome, in addition to other considerations such as acute tubular necrosis or renal vein thrombosis [6]. Abdominal compartment syndrome may potentially cause venous thrombus development from stasis and may precede the development of renal vein thrombosis. Further study with intra-abdominal pressure measurement or indirect pressure measurement from the urinary bladder before, during, and after transplant surgery, coupled with Doppler ultrasound evaluation of the blood flow characteristics of the transplanted kidney, may provide more concrete evidence of this phenomenon.
References 1. Ferris RL, Kittur DS, Wilasrusmee C, et al (2003) Early hemodynamic changes after renal transplantation: determinants of low central venous pressure in the recipients and correlation with acute renal dysfunction. Med Sci Monit 9:CR61– 66
2. Berger P, Nijsten JC, Paling JC, et al (2001) The abdominal compartment syndrome: a complication with many faces. Neth J Med 58:197–203 3. Doty JM, Saggi BH, Blocher, et al (2000) Effects of increased renal parenchymal pressure on renal function. J Trauma 48:874–877 4. Bendahan J, Coetzee CJ, Papagianopoulos C, et al (1995) Abdominal compartment syndrome. J Trauma 38: 152–153
5. Nebelkopf H (1999) Abdominal compartment syndrome: Am J Nurs 99:53–59 6. Kaveggia LP, Perella RR, Grant EG, et al (1990) Duplex Doppler sonography in renal allographs: the significance of reversed flow in diastole. AJR 155: 295–298
