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PHOENIX -- A tool to project a virtual roadmap for percutaneous coronary intervention (PCI) onto the fluoroscopy image reduced contrast volume used, the randomized trial showed.

The Dynamic Coronary Roadmap reduced total iodine contrast volume per procedure by 28.8% (95% CI 18.9%-38.2%) on average compared with conventional angiographic guidance, Javier Escaned, MD, PhD, of the Hospital Clinico San Carlos in Madrid, reported at the annual EuroPCR meeting in Paris.

The automated software tool also significantly reduced the number of angiograms per procedure by a relative 26.3% on average (8.7 vs 11.7 runs, P<0.001).

Higher quality roadmaps had a larger impact on contrast volume used, and the roadmap quality was even higher in multivessel than single vessel disease, according to additional late-breaking trial findings reported a day later by John Messenger, MD, of the University of Colorado Anschutz Medical Campus in Aurora, at the Society for Cardiovascular Angiography and Interventions (SCAI) meeting in Phoenix.

"I think contrast nephropathy or acute kidney injury related to contrast is the biggest challenge in complex coronary disease," Messenger said at a SCAI press conference. "As we get to more complex and older patients with high rates of underlying chronic kidney disease, this is a very simple tool that saves us."

The FDA-cleared software integrates into the interventional X-ray system to provide a real-time, motion-compensated dynamic overlay of the position of guidewires and catheters in the coronary tree throughout the PCI procedure for Philips systems.

"A 26% drop in contrast may not wow you when you hear it, but it's critical if it can keep an older patient from going into renal failure," agreed David Cox, MD, past president of SCAI and moderator of the SCAI press conference. "We're doing a lot more interventions on older patients."

Messenger emphasized the real-world nature of the trial results, as all operators at the participating centers were included regardless of their experience level with the coronary roadmap system, paired with a fairly all-comers patient population.

The patient characteristics in this trial were typical of patients coming for largely elective PCI (ad hoc and planned PCI were allowed), Messenger said. He pointed to the relatively low kidney injury risk patient population with an average age of 66, about 20% women, 10-15% with chronic kidney disease, about 35% with prior revascularization, and fairly high estimated glomerular filtration rate (around 76 mL/min x 1.73 m²).

Of the 371 patients enrolled and randomized to either the roadmap guidance or standard angiographic guidance at the centers in the U.S., Israel, Belgium, and Spain, the coronary roadmap was deemed "good" or "very good" quality for 79%. Less than 5% had a "poor" or "very poor" quality roadmap generated. The roadmap was able to be used in 98% of cases.

Contrast volume used averaged 64.6 mL with the roadmap guidance versus 90.8 mL with usual guidance (P<0.001). While there was no significant difference between groups among patients with the lowest complexity scores, there was for those with intermediate and higher vessel Syntax scores (62.9 vs 92.9 mL contrast used in those with scores of 4 to less than 8, and 70.4 vs 115.2 mL in those with scores of 8 or greater, both P<0.001).

Contrast volume used was numerically lower with even "fair" to "very poor" quality roadmaps than with conventional guidance and significantly better with "good" or "very good" roadmaps (P=0.036 vs lower quality roadmaps and P<0.001 vs controls). The pattern was similar for number of cineangiograms.

When asked at the session how the roadmap was able to have such a large impact on contrast use, Messenger noted that the map is on for the duration of the procedure, not just insertion.

"If I move the gantry and take other pictures and then come back to it and I haven't moved my catheters, the roadmap is available at any time. So it keeps that in the library, so you don't have to retake the angiogram," he said.

"Many operators don't really realize how much contrast they use," he added. "I'm in a training program with fellows, so you're sitting there injecting contrast and injecting contrast so that they can navigate these vessels. But if you can use these models and really use tactile and visual tactile skills to wire these, position stents, and do all that, it really has the potential to lower this."

Limitations of the study included its unblinded design and sample size not powered for clinical outcomes, although acute kidney injury was numerically lower with the roadmap than the usual care group (1.7% vs 2.4%, P=0.72). Also, the study period, from November 2019 to February 2023, encompassed the COVID-19 pandemic.