Marlene Busko

May 06, 2016

ORLANDO, FL — In the AVERT trial of close to 600 patients who underwent coronary angiography and were at high risk of contrast-induced acute kidney injury (AKI), the studied device successfully reduced the volume of contrast agent by 15.5%, but this did not translate into a lower risk of kidney damage[1].

Specifically, 27.0% of patients who had angiography that included use of the AVERT device (Osprey Medical, Minnetonka, MN) developed contrast-induced AKI, which was not significantly different from the control group (26.2%; P=0.72).

On the positive side, there was no significant difference in adverse events, and the quality of the images of the coronary arteries was good with the reduced volume of contrast agent.

Moreover, in a subgroup of patients with moderate kidney function, this system resulted in half the rate of contrast-induced AKI—but this finding was from a post hoc analysis and should be interpreted with caution, the researchers say.

Dr Roxana Mehran (Icahn School of Medicine at Mount Sinai, New York, NY) presented these findings in a late-breaking clinical-trial session and in a press briefing here at the Society for Cardiac Angiography and Interventions (SCAI) 2016 Scientific Sessions.

Dr Roxana Mehran

AVERT was a very large study and was very successful in reducing the volume of contrast dye, she told heartwire from Medscape. However, the trial showed that "maybe you need more reduction, because 15% wasn't enough to reduce contrast-induced acute kidney injury" in these high-risk patients, she added.

Panelist Dr Ron Waksman (MedStar Cardiovascular Research Network, Washington, DC), told heartwire that "this study probably was not powered enough to take all-comers, including patients with normal [kidney function], and see that 15 cc of contrast makes a difference."

Similarly, session comoderator Dr Steven R Bailey (University of Texas Health Science Center in San Antonio) said that it is unknown what optimal reduction in dye volume will reduce the risk of AKI. The current study reminds clinicians "that this is a high-risk group, if one in four patients with these characteristics develop contrast nephropathy."

Aiming to Improve PCI Performance and Outcomes

Minimizing the amount of contrast dye used in patients undergoing PCI is one of the quality metrics in the NCDR Cath-PCI registry, Mehran noted.

The AVERT device is designed to enable the operator to inject enough contrast dye to visualize a patient's coronary arteries, and then the excess dye is diverted to a reservoir (rather than into the aorta), ready to be used for the next injection.

In a single-center pilot study in 21 patients, the device was safe, and 40% less dye was injected with no loss of image quality.

Building on this, the current study randomized 578 high-risk patients who were about to undergo PCI at 39 centers mainly in the US to a control group or to a device group.

Patients were at high risk of AKI since they had an estimated glomerular filtration rate (eGFR) of >20 and <30 mL/min/1.73 m2 or an eGFR of >30 and <60 mL/min/1.73 m2 with at least two risk factors (NYHA class 3 or 4, diabetes, albuminuria, anemia, medically treated hypertension, or age 75 and older).

The protocol called for patients in both groups to be well hydrated.

The patients had a mean age of 72, and 39% were women. They had a mean eGFR of 45 mL/min/1.73 m2. Almost all had hypertension; two-thirds had diabetes; and 40% had anemia.

Patients had blood drawn at 48 and 72 hours (and 96 and 120 hours if needed) and were followed for 30 days.

Clinicians used a mean of 101.3 mL of contrast agent in the control group vs 85.6 mL of contrast agent in the AVERT group, which was a significant 15.5% difference (P=0.22). The volume of dye used was most reduced in patients in the device group who had PCI with two or three or more lesions.

Contrast-induced AKI (defined as a 0.3-mg/dL absolute increase in serum creatinine within 72 hours) occurred in 563 patients. There was no significant difference in the rate of contrast-induced AKI in the control group vs the device group. There was also no significant difference in adverse events or in the quality of the images.

However, a post hoc analysis of 264 patients with moderate kidney failure (eGFR >40 to <60 mL/min/1.73 m2) showed that contrast-induced AKI occurred in 10.9% of patients in the group treated using the AVERT system vs 21.5% of patients in the control group (a difference of 49.5%; P=0.02).

"The benefit that we saw in patients with moderate kidney disease warrants further investigation and is only hypothesis generating," Mehran said.

"The threshold is off, but I think if we could use this system . . . so it doesn't add too much cost or too much work, you reduce the dye and you help the patients, and for sure you are going to save more kidneys that way at some point," she told heartwire . "If it reduces just one contrast-induced acute kidney injury, it's worth it, because it's such a bad complication."

The company has developed a new-generation device, the DyeVert system, "which is much more automated and hopefully it'll be better," she said.

Mehran received a research grant from Osprey Medical. Disclosures for the coauthors are listed in the abstract.

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