Mehran.qxp 10/10/08 9:12 am Page 10
Diagnostics and Imaging
Contrast-induced Nephropathy in a High-risk Patient Population
a report by
Adriano Caixeta, Eugenia Nikolsky and Roxana Mehran
Cardiovascular Research Foundation, New York
Contrast-induced nephropathy (CIN) is one of the most common causes direct toxic effects of contrast medium on renal epithelial cells and oxidative
of hospital-acquired acute renal failure.
1,2
The development of CIN after stress.
16–20
Iodinated contrast is known to provoke acute vasoconstriction
diagnostic coronary angiography and/or percutaneous coronary due to a release of adenosine, endothelin and other renal vasoconstrictor
intervention (PCI) is associated with prolonged hospitalisation and a agents. Apoptosis has also been implicated as a contributing factor.
21,22
remarkable increase in morbidity, early and late mortality and costs.
3–6
CIN is an absolute (≥0.5mg/dl) or relative (≥25%) increase in serum Prevention of Radiocontrast Nephropathy
creatinine compared with baseline after exposure to a contrast agent The unfavourable prognostic implications of CIN in high-risk populations
when alternative explanations for renal impairment have been excluded. make preventing this condition of paramount importance.
20
The Contrast-induced Nephropathy Consensus Panel recommended
using a relative increase in serum creatinine to define CIN given that this Hydration
definition is independent of baseline renal function.
7
CIN typically Volume supplementation results in plasma volume expansion
develops within 24–72 hours post-exposure to contrast medium, with followed by suppression of the renin–angiotensin–aldosterone system
renal function returning to baseline level in two weeks.
8–10
The overall and downregulation of tubuloglomerular feedback, leading to the
incidence of CIN in the general population is <2%.
1,11
In high-risk attenuation of renal cortical vasoconstriction and tubular obstruction
patients, including the elderly population and patients with chronic renal triggered by contrast agents.
23,24
The positive effect of adequate
impairment, diabetes, congestive heart failure and anaemia, the hydration in reducing CIN rates was first established in the randomised
incidence of CIN is much higher (≥20%).
8–10,12,13
Several risk factors have study by Solomon et al.
25
In patients with mild to moderate renal
been described for CIN.
6,14
To reliably assess the risk of CIN, a simple risk insufficiency, 0.45% saline administration at a rate of 1ml/kg/hour for
score (see Figure 1) that can be quickly calculated based on readily 12 hours pre- and post-procedure was more effective in the prevention
available information is strongly recommended.
15
of CIN than a combination of 0.45% saline and mannitol or furosemide
(10.7 versus 28.0 versus 40.0%, respectively; p=0.02 for the comparison
Pathogenesis of Contrast-induced Nephropathy with the saline group alone). The randomised comparison of two
The pathogenesis of CIN is not entirely understood. Several pathways of CIN hydration regimens in a total of 1,620 patients undergoing coronary
development have been proposed, including altered rheological properties angioplasty in the study by Mueller et al. showed the superiority of
of blood, medullary hypoxia, impaired immunological mechanisms and isotonic versus half-isotonic saline in reducing rates of CIN (0.7 versus
2%, respectively).
26
Although a randomised study by Taylor et al.
Adriano Caixeta is a Post-doctoral Research Fellow in
demonstrated that in high-risk patients different modes of fluid
Interventional Cardiology at Columbia University Medical administration (intravenous versus oral) had similar renoprotective
Center and the Cardiovascular Research Foundation in New
effects,
27
this was not confirmed in another randomised study by Trivedi
York. He received his undergraduate degree from the Medical
School of the Federal University of Goias in Brazil and
et al.,
28
which showed a significantly lower incidence of acute renal
completed his residency in interventional cardiology at the
failure in patients who received normal saline at a rate of 1ml/kg/hour for
Heart Institute at the University of Sao Paulo in Brazil, where
24 hours starting 12 hours before contrast exposure compared with a
he later obtained a PhD in interventional cardiology.
protocol of unrestricted oral fluids. In studies by Bader et al.
29
and
Roxana Mehran is Joint Chief Scientific Officer of the
Krasuski et al.,
30
rates of CIN were lower in patients who received
Cardiovascular Research Foundation and an Associate hydration with saline for 12 hours before and after exposure to contrast
Professor of Medicine at Columbia University Medical Center.
medium compared with patients who were administered 250–300ml
She is internationally recognised for her work in complex data
analysis and outcomes research in the field of interventional
saline bolus immediately before or during contrast media exposure. To
cardiology, and for her experience and expertise in working
conclude, volume supplementation with saline should be considered in all
with the US Food and Drug Administration (FDA). In addition
to founding a highly regarded academic research organisation
patients undergoing contrast medium exposure during diagnostic or
within the Cardiovascular Research Foundation, Dr Mehran is therapeutic coronary procedures. Patients with chronic kidney disease
a widely published author in the most respected cardiovascular journals, and has authored or
and impaired left ventricular function should receive cautious hydration.
co-authored a significant number of books and book chapters. She has been an invited speaker
at various international medical conferences and has served as Course Co-Director of the annual
In the presence of chronic kidney disease, for patients with a normal
Transcatheter Cardiovascular Therapeutics (TCT) for the last 15 years. Dr Mehran completed her
ejection fraction we recommend hydration with isotonic saline
training in internal medicine at the University of Connecticut before continuing her studies in
1cc/kg/hour for at least 12 hours pre- and post-procedure, while for
cardiovascular medicine and interventional cardiology at the Cardiovascular Institute at Mount
Sinai Medical Center in New York City. patients with moderately/severely reduced left ventricular ejection
E:
rmehran@crf.org
fraction a hydration regimen should be performed with 0.45% saline
matching urine output to maintain a euvolemic state.
10 © TOUCH BRIEFINGS 2008
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