Robotic PCI via radial, femoral access yields high success

NEW ORLEANS — Access route does not appear to impact the clinical success or safety of robotic PCI. In a post hoc analysis of the PRECISION study, robotic procedures performed via transradial or transfemoral access yielded high clinical success, comparable radiation exposure and similar procedure times.

“We’re still in the early stages, but adoption and utilization [of robotic PCI] is increasing,” Ehtisham Mahmud, MD, FSCAI, professor and division chief of cardiovascular medicine at University of California, San Diego, said during a press conference at the Society for Cardiovascular Angiography and Interventions Annual Meeting.

The main benefit of robotic PCI — during which the operator is seated in a cockpit and has remote control of the guide catheters, guidewires and stents/balloons — is limited radiation exposure to the primary operator, he said.

The post hoc analysis focused on the safety and efficacy of radial vs. femoral access robotic PCI in clinical practice at 16 U.S. centers that used the first-generation CorPath 200 system (Corindus Vascular Robotics). Mahmud said this was not a randomized comparison of radial vs. femoral access. The decision of access route was based on the operator’s discretion.

From September 2013 to March 2017, 754 robotic PCI procedures were performed in 949 lesions. Sixty percent of cases used the radial approach (n = 298) and 40% used the femoral approach (n = 452). Mahmud noted that the majority of robotic PCI performed in clinical practice was in type B2/C lesions. “In previous [robotic PCI] studies, very few of these patients [with type B2/C lesions] were enrolled,” he said.

The analysis had two main endpoints: clinical success (residual stenosis < 30% and final TIMI 3 flow without MACE) and technical success (residual stenosis < 30%, final TIMI 3 flow without MACE or any unplanned manual assistance). MACE comprised CV death, MI or urgent target vessel revascularization.

Clinical success was high with both access strategies, at 98.9% with radial robotic PCI and 94.9% with femoral robotic PCI (P = .0012).

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Technical success was lower, at 88.6% with radial robotic PCI and 82.4% with femoral robotic PCI (P = .017). Approximately 12% of robotic PCI procedures required manual conversion (12.1% femoral group; 11.7% radial group).

Mean fluoroscopy time was slightly longer with femoral PCI (48.1 minutes vs. 40.9 minutes; P = .0014). Contrast volume was higher with radial PCI (185.4 cc vs. 174.2 cc; P = .52). Mean dose area product was similar between the two groups.

Mahmud cautioned against broad interpretation of these data, as there were “dramatic differences” between the two groups in terms of baseline characteristics. The femoral group was older, had lower BMI, greater prevalence of diabetes and more calcified lesions. The radial group had fewer comorbidities and less complex lesions, he said.

The researchers conducted a propensity matched analysis (n = 205 in each group) to adjust for the baseline differences. Outcomes were comparable, but there remained a slight difference in clinical success favoring the radial group. According to Mahmud, this difference was primarily driven by a higher rate of MACE in the femoral group.

The researchers also looked at lesion length estimation based on visual or robotic estimation. In both groups, visual measurement of lesion length was underestimated compared with robotic measurement. This resulted in stent selection change in 22.5% of the femoral group and 33.2% of the radial group (P = .005).

During a discussion of the trial, panelists raised a question about the learning curve associated with robotic PCI. In this study, Mahmud said each site had more than one individual performing robotic PCI, as opposed to previous studies that were often single center or done by a single operator. “Previously, we’ve shown that probably 25 cases is where your procedure time decreases, and 50 is where it really plateaus,” he said. Mahmud said this will be a point of further research from the PRECISION registry.

Although this analysis focused on the first-generation system, the next-generation CorPath GRX system was cleared by the FDA in late 2016. The main difference between the first- and next-generation systems is that the latter enables guide catheter control and “could help reduce the need for manual assistance,” Mahmud said. The PRECISION registry is now extending to evaluate outcomes with the newer CorPath GRX system, he said.

Mahmud estimated that about 40 centers in the United States are currently using the robotic PCI system.

“As technique improves, there’s potential for wider-spread utilization” of robotic PCI, he said.

Looking ahead, with a “futuristic” point of view, Mahmud discussed the possibility of an experienced robotic PCI operator at large health care systems to assist less-experienced operators at other sites, or performing rural complex PCI procedures with the help of a central support system.

Reference:

Mahmud E, et al. Late-Breaking Clinical Trials II. Presented at: Society for Cardiovascular Angiography and Interventions Annual Meeting; May 10-13, 2017; New Orleans.

Disclosure: Mahmud reports financial relationships with Abbott Vascular, Abiomed, Corindus Vascular Robotics and Medtronic.