Marlene Busko

May 16, 2017

NEW ORLEANS, LA — Clinical and technical success rates from the PRECISION registry of more than 900 lesions treated by multiple operators using the first-generation CorPath200 (Corindus) robotic system for PCI were very high, researchers report[1].

Operators at 16 sites in the US could choose a femoral or radial approach, and they chose a femoral approach in 60% of the robotic procedures.

Clinical success—defined as residual stenosis <30% and final TIMI 3 flow without a major adverse cardiovascular event (MACE; defined as CV death, MI, or urgent need for target vessel revascularization)—was achieved in 95% of femoral-access procedures and 99% of radial-access ones (P=0.0012).

Similarly, technical success (clinical success without the need for manual assistance) was achieved in more than 85% of procedures, with slightly higher success rates in the radial-access group.

Dr Ehtisham Mahmud

"I would like to caution the interpretation" of these statistical differences, because patients in the femoral-access group had "dramatically" more comorbidities and more complex lesions, said Dr Etisham Mahmud (University of California, San Diego) in a press briefing here at the Society for Cardiovascular Angiography and Interventions (SCAI) 2017 Scientific Sessions.

After correction for baseline patient differences, "clinical success, technical success, patient radiation exposure, and PCI procedure times were comparable to either radial or femoral access for robotic PCI," Mahmud said in a late-breaking clinical-trial session.

Robotic PCI is increasing and is now being performed at close to 40 clinical centers in the US, he told heartwire from Medscape. "I think we're still in the early stages, but the . . . utilization is increasing.

"The major benefits are [that] you essentially eliminate radiation exposure for the primary operator." In the future, a large health system could have an experienced operator at one site helping less experienced operators at other sites.

"It's an emerging technology," session comoderator Dr Robert J Applegate (Wake Forest Baptist Health, Winston-Salem, NC), whose hospital does not have this technology, agreed in a comment to heartwire .

"It's going through a process of improvement, refinement, and, certainly for an interventional cardiologist who's interested in minimizing radiation and doing it in a way that preserves the ability to do an effective, really good job with a PCI, this is very appealing."

Robotic PCI will become more common in clinical practice in the next 5 years, he speculated.

Large Clinical Study of Complex Lesions

The feasibility of robotic PCI using the CorPath200—which gives operators the ability to remotely control guide wires, guide catheters, and deliver balloons and stents—was first reported in the PRECISE trial, Mahmud said.

That trial found a high clinical success and radiation reduction to the primary operator, but the lesions were 12 mm long on average, and most (83%) were non-C lesions.

The current study aimed to evaluate clinical success with the CorPath 200 in "all comers" who had robotic PCI at the 16 US sites that were part of the PRECISION registry, from September 2103 to March 2017.

The operators performed 754 robotic PCI procedures on 949 lesions. They used a femoral-access approach in 289 procedures on 399 lesions and a radial-access approach in 452 procedures on 544 lesions.

In general, patients who underwent PCI that used a femoral-access approach were older and had lower BMIs and a higher prevalence of diabetes, and "most important," they had fairly complicated lesions, greater lesion calcification, and more lesions treated per procedure, Mahmud said.

Roughly two-thirds of the lesions treated with PCI using either access approach were type B2 and C lesions. On average, there were 1.1 stents per lesion in both groups.

Operators often underestimated the lesion length visually compared with the actual length that they measured using the robotic platform; they subsequently changed their stent selection in 22% of femoral-access procedures and 33% of radial-access procedures.

Approximately 12% of cases in both access types required manual assistance.

In a propensity-matched analysis of 205 patients who had femoral-access PCI and the same number of patients who had radial-access PCI, clinical success was slightly higher in those in the radial-access approach—primarily driven by lower rates of MACE in this group (six versus zero).

A total of 82% of femoral-access procedures and 89% of radial-access ones (P=0.017) were technically successful.

The procedure time was 8 minutes longer with femoral-access vs radial-access PCI (48 vs 40 minutes); however, patient radiation exposure was similar in both groups.

"I've got to admit that I was a little bit surprised that the radial-[access PCI group] had a higher technical success rate. . . . Were you?" Applegate asked.

Mahmud admitted that he was. He suggested that "in general, the people who were doing radial-access PCIs were probably choosing somewhat less complicated lesions, and I think there is a big selection bias." They may also have been more aggressive in their guiding catheter use.

Short Learning Curve, Second-Generation CorPath GRX Approved

The learning curve is very short for simple cases: three to five cases, Mahmud told heartwire . But as lesion complexity increases, the procedure time falls after about 25 cases and it drops again and plateaus after 50 cases.

The technical success rate will likely be even higher with the new second-generation CorPath GRX system that was recently approved by the US Food and Drug Administration (FDA).

Data to evaluate this device are being collected in the PRECISION GRX registry.

At their center, manual assistance was used in PCI procedures in 18% of patients; 45% of the time it was required to guide the catheter.

"With the new robotic system, you can now robotically control the guiding catheter, and that should limit the number of patients who require manual conversion," according to Mahmud.

The study was sponsored by Corindus Vascular Robotics. Mahmud disclosed that he is a consultant for and receives research support from Corindus Vascular Robotics. Applegate disclosed that he is a consultant for Abbott.

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