Procedural Success Increasing for CTO PCI in Europe, Despite More Complex Lesions

The procedural success of chronic total occlusion (CTO) PCI has been steadily increasing despite rising lesion complexity, according to new observational data derived from centers across Europe.

“CTO PCI evolved for a decade and is reaching a period of standardization in terminology and practice,” write Nikolaos V. Konstantinidis, MD (AHEPA University Hospital, Thessaloniki, Greece), and colleagues. “Patients with increasing comorbidities and lesion complexity are currently treated with a success rate of > 90%. Many lessons learned from these techniques passed to the non-CTO PCI field dramatically increasing effectiveness and safety. CTOs are not any more an isolated anatomic entity but the leading edge of the complex PCI field and as such should be considered and evolve further in parallel with technological evolution.”

Published online October 9, 2018, in Circulation: Cardiovascular Interventions, the study included 17,626 CTO PCI procedures performed by 53 operators in Europe between January 1998 and June 2015. Over time, patient age as well as the prevalence of diabetes, hypertension, and renal failure rose and the mean J-CTO score—a risk prediction algorithm derived from the Multicenter CTO Registry of Japan—went up from 1.76 to 2.17 (P < 0.001 for trend).

Despite the higher patient risk, procedural success went from 79.7% to 89.3% during the study period. Use of the retrograde approach (10.1% to 29.9%) and radial access both increased (16.2% vs 33.5%; P < 0.001 for trends).

In-hospital mortality dropped from 0.4% to 0.1%, and the in-hospital MACE rate hovered around 0.7% throughout the study. The overall rate of any periprocedural complication remained “essentially unchanged” over time, shifting from 5.2% to 4.4%.

Standardization, Shift in Focus

In an accompanying editorial, Emmanouil S. Brilakis, MD, PhD, and M. Nicholas Burke, MD (Minneapolis Heart Institute, MN), outline several ways in which the CTO space has advanced and what opportunities still remain. First, they point out that CTO PCI trials lack standard definitions for procedural techniques and outcomes. “There remains great need for standardizing CTO PCI definitions to facilitate communication and comparisons between various studies around the globe,” Brilakis and Burke write. “Definition standardization will be addressed in the CTO Academic Research Consortium that is planned for later in 2018.”

They also highlight that while “CTO operators are willing to attempt increasingly difficult lesions” with soaring procedural success, the findings only apply to operators and centers with experience. “At present, concentrating CTO PCI (especially for more complex CTOs) to experienced operators and centers will likely provide the best outcomes,” the editorialists suggest.

Speaking with TCTMD, David Kandzari, MD (Piedmont Heart Institute, Atlanta, GA), who was not involved with the research, said large observational studies like this one “tell us only a part of the story of CTO revascularization because they [include] site-reported events. There's no systematic capturing of events—for example, ensuring that all patients have periprocedural cardiac biomarkers to assess for periprocedural MI—so it’s very clinician-decision determined. And there’s no independent adjudication of events as well.”

Limitations like these are “especially important when we think about complication rates because we’ve seen in other studies like the Open CTO trial that what sites report as a perforation, for instance, is sometimes different from what an angiographic core lab or an adjudication committee would report as a clinically meaningful perforation event as well,” Kandzari added. The academic research consortium approach that the editorialists mention will likely be “at least one step toward comparing like versus like trials” in the future, he said.

Additionally, he mentioned the stark geographical differences in procedural technique for CTO PCI that have been shown previously indicate “that there is more than one way to achieve procedural success, that's the good part. [Yet this] also highlights the variance across operators and their approaches to treating chronic total occlusions based in part on regional teaching and training, and also based on their specific experiences and skill sets, and third related to what technologies are commercially available to them in other parts of the world.”

As far as which approach would be optimal for CTO PCI, Kandzari said that since the time this study ended, “my estimate is that we are probably observing a decline in retrograde procedures, and this is because of increasing utilization of antegrade dissection methods and techniques. It's also paralleled by the increasing awareness of the higher complication rate that's associated with retrograde procedures.” As such, “an antegrade approach for the majority of CTOs would probably be still the dominant preferred procedure as well,” he said.

An overarching issue for CTO PCI remains not merely can it be done but should it? The only major randomized clinical trial in this space, DECISION-CTO, came up empty-handed last year, failing to show a benefit of CTO PCI over optimal medical therapy for an endpoint of all-cause death, MI, stroke, and repeat revascularization at 3 years.

Kandzari said he would like to see future trials focus more heavily on clinical outcomes, but that in his mind, they should emphasize patient self-reported health status.

“Like for most PCI, the intent is not for PCI to be a lifesaving procedure but rather to improve symptoms and quality of life and reduce the angina burden and perhaps medications for patients,” he explained. “This is really where I think we need to apply greater focus on CTO clinical trials to unequivocally demonstrate that value for these patients who are often described as being no-therapeutic-alternative or no-option patients.”

Another issue is ensuring that patients are enrolled consecutively, “rather than us selectively submitting to clinical trials which patients we think or do not think would be good for a clinical study,” Kandzari concluded. “Because what we've seen in so-called all-comers or consecutive-CTO patient trials is that the symptom burden is even greater, that these are typically even sicker patients, and as you might expect, these are the ones that derive an even greater benefit from successful revascularization.”