Coronary CTA Before PCI Proves Beneficial for Chronic Total Occlusion Patients in Latest Study
Kim Byeong-Keuk, MD, PhD from Severance Hospital presents CT-CTO trial findings, highlighting use of coronary CTA in CTO-PCI
Coronary CT angiography (CTA) proved to be a promising strategy for increasing the success rate of percutaneous coronary interventions (PCI) in patients with chronic total occlusion (CTO), according to CT-CTO study findings presented at COMPLEX PCI 2020.
Findings from the domestically-conducted randomized trial showed CTO patients who underwent coronary CTA before PCI had better clinical outcomes than those who underwent PCI without a coronary CTA.
Kim Byeong-Keuk, MD, PhD (Yonsei University College of Medicine, Severance Hospital, Korea) presented these findings at COMPLEX PCI 2020, which ran online for two days from Nov. 26 to 27.
Kim Byeong-Keuk, MD, PhD (Yonsei University College of Medicine, Severance Hospital, Korea) presents CT-CTO trial findings at COMPLEX PCI 2020 VIRTUAL on Nov. 26
Lack of randomized data for coronary CTA in CTO-PCI
Although innovative techniques and devices have opened the door to a minimally invasive treatment beyond medication or open heart surgery, patient characteristics - lesion length, presence of plaques, and side branch (SB) occlusion, among others – often influence clinical outcomes.
For these reasons, interventionalists emphasize the importance of planning a treatment strategy that incorporates preprocedural angiograms and CT-based imaging tests in particular.
Coronary CTAs can be utilized to identify CTO while also predicting the level of difficulty with which an operator can cross a CTO. The imaging technique can also aid in preprocedural planning, visualization during the procedure, and long-term follow-up of recanalized coronary segments, among others.
Although experts have signaled that coronary CTAs could play a larger role in predicting the prognosis of post-PCI CTO patients and in selecting a procedural strategy to improve CTO-PCI success rates, the lack of definitive randomized evidence for coronary CTAs in the CTO-PCI sphere has created some uncertainty.
Prior to the CT-CTO study, non-randomized data came from a 2013 study, led by German researchers, that discovered a 90 percent success rate in the 30-person CTO-preprocedural coronary CTA group versus a 63 percent success rate in the 43-person control group.1
Coronary CTA proves higher recanalization rate than angiography
The CT-CTO study –led by researchers from Severance Hospital –is the first randomized study to prove the usefulness of coronary CTA performed prior to PCI in 400 Korean CTO patients at 12 domestic medical institutions.
Investigators enrolled CTO patients eligible for PCI who were 19 years or older with a TIMI grade flow of 0 and a coronary artery occlusion period of at least three months.
Patients were randomly assigned in a 1:1 ratio to either a preoperative coronary CTA group or an angiography group.
The primary endpoint was the recanalization rate, defined as residual stenosis in final coronary angiography (CAG) < 30 percent and TIMI grade flow ≥2.
Upon investigating the superiority of preprocedural coronary CTA to preprocedural angiography alone, the coronary CTA group demonstrated a roughly 10 percentage point higher rate of recanalization than the angiography group (94% vs. 84%, 95% CI 3.4-15.6).
Sub-analysis based on 257 patients with a J-CTO score ≥2 showed the coronary CTA arm had a recanalization rate of 93 percent while the angiography group had a rate of 77 percent (P<0.001).
When examining a 143-person subgroup with a J-CTO score ≥2, the recanalization rate in the coronary CTA group was 95 percent, and 97 percent in the angiography group, indicating no statistically significant difference (P=0.434).
The procedural success rate – defined as having TIMI grade flow ≥2 without death or fatal complications – was 94 percent in the coronary CTA group and 84 percent in the angiography group, indicating significant clinical benefits of coronary CTA over angiography-alone (P=0.003).
The device success rate – defined as residual stenosis <30 percent after successful stenting – likewise significantly favored coronary CTA over angiography-alone, with the coronary CTA arm showing a 95 percent device success rate and a 85 percent success rate in the angiography arm.
Investigators noted that, although there was no statistically significant difference, the incidence of type II coronary perforation was four percent lower in the coronary CTA arm than the angiography arm (1% vs. 4%, P=0.055). Perioperative myocardial infarction did not occur at all in the coronary CTA group but occurred in two percent of the angiography group (P=0.123).
“Utilizing coronary CTA to visualize the CTO course and plaque characteristics such as calcification geometry could be helpful in navigating and selecting the proper antegrade and retrograde wires and devices without increasing the risks of procedural complication,” Kim said. “Operators could also increase the success rate of CTO-PCIs by employing a strategy for reattempt based on data from various longitudinal and cross-sectional coronary CTA analyses.”
Kim added that the coronary CTA group maintained a positive prognosis at one year post-PCI. The composite incidence of CV death, target vessel related-MI, ischemia-driven TVR at one year was 21 percent lower in the coronary CTA group than the angiography group, although this was also not statistically significant (P=0.614). Kim argued, however, that the short duration of the study was a limitation in properly studying the effect of preprocedural coronary CTA versus angiography alone.
“The CT-CTO study demonstrated for the first time that coronary CTAs in CTO-PCIs offers assistance to a higher rate of recanalization and lower incidence of complications” Kim said. “Preprocedural coronary CTA also proved to be effective in CTO-PCI patient groups that are deemed difficult to treat based on a high angiographic score.”