AMSTERDAM—A fluid protocol based on left ventricular (LV) end-diastolic pressure may prevent contrast-induced acute kidney injury (AKI) in patients with stable renal insufficiency undergoing cardiac catheterization, researchers reported at the 51st Congress of the European Renal Association- European Dialysis and Transplant Association.

“The hydration regimen is very easy to adopt into in clinical practice and does not interrupt the flow of the procedure,” said principal investigator Somjot Brar, MD, director of vascular medicine at Kaiser Permanente Los Angeles.  “It is also inexpensive since patients do not have to be admitted 12 hours before the procedure or remain hospitalized for 12 hours afterwards. What’s more, it can be used in patients undergoing outpatient or in-hospital cardiac catheterization.”

He emphasized, however, that the protocol is not suitable in patients with  decompensated heart failure as well as patients with severe valvular heart disease.

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Dr. Brar and his colleagues randomized 396 patients to LV end-diastolic pressure-guided volume expansion or to a standard fluid administration protocol as part of the phase 3 Prevention of Contrast Renal Injury with Different Hydration Strategies (POSEIDON) study. Study participants had an estimated glomerular filtration rate (eGFR) of 60 mL/min per 1.73 m2 or less and at least one of several contrast nephropathy risk factors.

“Even though the administration of intravenous fluid remains a cornerstone treatment for the prevention of contrast-induced AKI, there is scant information on the optimal rate and duration of fluid administration,” Dr. Brar said. “Available guidelines generally recommend hydration and usually with normal saline; however, there have been no head-to-head comparisons of volume expansion with saline at varying rates or durations in populations at risk including patients undergoing coronary catheterization.”

About 15%-25% of patients with an eGFR of 60 or less undergoing cardiac catheterization—the study’s target population—are at risk of AKI, he added.

Dr. Brar explained that the LV end-diastolic pressure was selected for evaluation because it is a hemodynamic parameter routinely obtained during cardiac catheterization and is a measure of intravascular volume status. “The rationale is that the pressure itself corresponds ‘fairly reliably’ with intravascular volume and that the pressure value can be used to identify patients who are candidates for much more aggressive hydration.”

The primary endpoint was a greater than 25% or 0.5 mg/dL increase in serum creatinine concentration.

Contrast-induced AKI occurred in 6.7% of patients randomized to hemodynamic guided-fluid administration who were followed for up to 6 months after their procedure compared with 16.3% of control patients, with a significant 59% relative risk reduction in the primary endpoint with the novel hydration regimen and a significant 9.5% absolute risk reduction.

The 6-month rate of major adverse clinical events was 3.1% and 9.5% in the two groups, respectively.

Dr. Brar noted that his institution now routinely uses the hydration protocol tested in this study.

It is important that the pressure measurement be obtained at the start of the procedure to allow fluids “to be set” prior to administration of the contrast agent, he said.