CTO PCI: Lower Success, More Complications vs Other Complex PCI

Compared with other types of complex PCI, chronic total occlusion (CTO) PCI is less often associated with procedural success and carries a higher risk of complications such as coronary perforation and tamponade, according to a single-center analysis. However, the rates of other in-hospital and long-term adverse events are similar.

“To the best of our knowledge, no study so far [has] investigated the long-term outcomes of CTO versus complex non-CTO PCI,” write lead author Lorenzo Azzalini, MD, PhD (Mount Sinai Medical Center, New York, NY), and colleagues. “Our report provides reassuring data to this regard, as we found no differences in the primary endpoint of target lesion failure or any of its individual components between CTO and complex non-CTO PCI at 36-month follow-up.”

For the study, published online recently in the American Journal of Cardiology, the researchers included 2,396 patients undergoing PCI at their institution between 2012 and 2017 for CTO or otherwise complex lesions, with the latter defined as three vessels treated, three or more stents implanted, total stent length > 60 mm, saphenous vein graft intervention, bifurcation intervention with two stents excluding left main, left main PCI with one or two stents, protected PCI, or use of rotational or laser atherectomy.

CTO patients (n = 609), who were generally younger and had a greater burden of cardiovascular comorbidities, saw a lower rate of procedural success compared with those undergoing complex non-CTO PCI (74% vs 98%; P < 0.001). There was also more coronary perforation (3.5% vs 2.0%; P = 0.04) and cardiac tamponade (0.8% vs 0.1%; P = 0.001) seen after CTO compared with complex non-CTO PCI.

On the other hand, there was no difference in the incidence of target lesion failure—the primary endpoint comprised of cardiac death, MI, and target-lesion revascularization—or its individual components between CTO and complex non-CTO PCI at 36 months (10.1% vs 9.9%; P = 0.91). There was also no difference in the overall incidence of in-hospital MACCE (4.1% vs 5.0%; P = 0.40), a composite that included contrast-induced nephropathy requiring dialysis, tamponade, major bleeding (causing hemodynamic instability with need for vasopressors or requiring transfusion, percutaneous, or surgical intervention), stroke, periprocedural MI, and death.

On multivariate analysis, the type of PCI was not an independent predictor of target lesion failure, though lower estimated glomerular filtration rate (HR 0.93), lower LVEF (HR 0.81), higher number of diseased vessels (HR 1.32), and ACS presentation (HR 1.61) were.

“The results were as I expected, because it's a common concept among the operators that when we attempt to revascularize CTOs, we have a higher incidence of perforation and tamponade,” Azzalini told TCTMD. “However, what surprised me was the lack of difference in the overall MACCE rate between the two groups.” It’s possible that the somewhat low use of radial access—69% with complex and 50% with CTO cases (P < 0.001)—contributed to there being no difference in major bleeding, he added, “so that's why probably the overall incidence of MACCE between the two groups was not different.”

Overall, the study confirms that for CTO PCI, “at least when we pass this initial period of periprocedure complications, we know that the long-term outcomes are no different from patients undergoing other kinds of complex PCI,” Azzalini said.

Similarly High or Just Similar?

Commenting on the study for TCTMD, Ajay Kirtane, MD (NewYork-Presbyterian/Columbia University Irving Medical Center, New York, NY), said this kind of comparison between CTO and complex non-CTO PCI is important. “There's sort of a range of what we do in the cath lab, and so in a sense, if you compare CTO to non-CTO, that includes a lot of relatively simple lesions,” he said. “It's less of an ‘apples to apples’ comparison, so taking complex PCI and excluding CTO from that complex PCI mix, because they are normally included together, is helpful.”

Additionally, the study findings confirm what is already known—the higher rate of complication and lower rate of success with CTO PCI—but the novel finding lies in what was seen with target lesion failure, Kirtane added. “The fact that those rates are similar is somewhat of a new finding. The question is: is it similarly high or is it just similar? Because we do know that complex PCI as a whole has a higher rate of adverse events. I think the fact that CTO PCI just seems like other complex PCI in that way is reassuring that there's no excess late risk to patients when CTOs are opened for clinically-indicated reasons.”

For Emmanouil Brilakis, MD, PhD (Minneapolis Heart Institute, MN), who was not involved in the study, the overall MACCE rate for both groups was “fairly low.” He told TCTMD this suggests that “good outcomes can be achieved not only in the short-term but also in the long run” when PCI is performed in an experienced, high-volume center like the one in the study.

Still, he noted, there are “so many differences between the CTO group and the non-CTO group that it's hard to know how comparable those outcomes are.”

Both Kirtane and Brilakis pointed to the definition used in the study for complex non-CTO PCI as somewhat of an issue. Brilakis called it “a little soft because sometimes [a lesion] may not be that complex and you still have to put in a long stent length, so not all of the multivessel or multistent procedures are going to be complex.” Likewise, Kirtane said, “the definition of what is a complex PCI is something that is not clear, but I think the fact that they used a preestablished definition that makes some sense.”

Brilakis added that he suspects that cases with vein grafts, atherectomy, and bifurcations alone “might have slightly worse outcomes than the other ones.”

Looking forward he said he would like to see “more long-term data on both CTO and non-CTO complex interventions. Sometimes these patients are pretty sick to start with so their outcomes might not be the best. It doesn't mean necessarily that it's the procedure that did it. If they have poor outcomes to start with, even if they don't survive that long, their quality of life might improve during that time that they are still alive.”

Azzalini said that due to recent efforts to standardize CTO PCI, he envisions a future where procedural success rates will increase and complication rates decrease. This will be true “especially at centers and with operators that were not experts already, because there's been a gap in the past few years between very skilled operators, proctors, and key opinion leaders that we see at congresses and the rest of the world,” he predicted.

Brilakis guessed that CTO PCI success has already risen above what was seen in this study. “Now we have 85-90% in most centers, so one would expect that actually the outcomes would be even better today with the current techniques and the current results we're achieving in the cath lab,” he concluded.