Marenzi G, Marana I, Lauri G, Assanelli E, Grazi M, Campodonico J, Trabattoni D, Fabbiocchi F, Montorsi P, Bartorelli AL
N Engl J Med 2003 Oct 2;349(14):1333-40.
abstract (from PubMed)
Currently available methods for preventing contrast-induced nephropathy have not been shown to have clinical benefits in patients with significant pre-existing renal disease, nor has hemodialysis started immediately after exposure to contrast agents. In this study, the authors looked at hemofiltration (rather than dialysis) started 4-8 hours before contrast administration, in patients with renal impairment.
114 patients with chronic renal failure (creatinine greater than 2.0 mg/dl), scheduled to undergo coronary angiography and/or angioplasty, were randomized to either:
- continuous veno-venous hemofiltration, monitored in an ICU, with replacement isotonic fluid at a rate of 1000 ml/hr, started 4-6 hours before the procedure and continued for 18-24 hours after the procedure
- continuous intravenous infusion of isotonic saline at 1 ml/kg body weight per hour, monitored in a step-down unit, with the same schedule
Baseline serum creatinine was 3.1, creatinine clearance 26 ml/min. Average age was 69, prevalence of diabetes 30%, LV EF 50%, prevalence of patients with EF<40 was 25%.
Volume of contrast agent used: 247 ml in hemofiltration group, 258 in control group.
- Contrast-induced nephropathy, defined as an increase of more than 25 percent from the base-line in serum creatinine, occurred in 50% of control patients, vs 5% of hemofiltration patients.
- Emergency hemofiltration or hemodialysis, performed if there was oligoanuria for more than 48 hours despite administration of at least 1 g of furosemide (earlier if there was CHF), was required in 10 control patients but in none of the hemofiltration patients
- There was one in-hospital death in the hemofiltration group (cardiogenic shock) vs. 8 in the control group (3 MI with shock; 2 multi-organ failure; 2 refractory CHF and 1 ischemic stroke)
- During one year follow-up, permanent dialysis was required in 3 control patients and in one patient in the hemofiltration group; there were five additional deaths in the filtration group and nine in the control group
- The relative risk of death within one year in the control group compared to the hemofiltration group was 1.16 for patients with baseline serum creatinine concentration under 4.0 mg/dl and 3.53 in patients with baseline serum creatinine greater than 4.0.
Subset of patients with higher creatinine derived most of the benefitsOctober 8, 2003
In terms of one-year mortality, almost all of the benefit from hemofiltration is limited to patients whose initial serum creatinine was over 4.0 mg/dl. Presumably this also would hold for the other benefits (need for in-hospital hemodialysis, for example). Unfortunately, the authors do not describe how the other parameters they followed (renal function and in-hospital mortality) vary with this subgrouping. Also, they do not indicate what percentage of their patients were in this category.
If, indeed, most of the benefit is limited to patients with serum creatinine over 4.0, this could greatly reduce the number of patients who need this rather intensive approach. Perhaps more detail on this subgroup will be published elsewhere.
posted on 2003-10-08 09:53:01 by
Michael Jacobson, MD, MPH
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