CTO PCI Linked to Worse Outcomes in Patients With Prior CABG

Marlene Busko

March 24, 2020

A large meta-analysis has shown that percutaneous coronary intervention (PCI) of a vessel with chronic total occlusion (CTO) is associated with less success in patients who have undergone previous bypass surgery than in other patients.

Researchers found that technical procedural success was reduced by about 6% in those with a previous bypass procedure. In-hospital mortality, coronary perforation, and myocardial infarction were also higher with a previous coronary artery bypass graft (CABG).

"So for those patients, PCI should be done at an experienced center, because they are also more likely to require an advanced technique, like the retrograde approach," senior author Emmanouil S. Brilakis, MD, PhD, Minneapolis Heart Institute, told theheart.org | Medscape Cardiology.

"I think this study quantifies what we suspected for a long time," said Gregg W. Stone MD, director of academic affairs, Mount Sinai Heart Health System, New York City, commenting on the findings for theheart.org | Medscape Cardiology.

"Clinicians need to be aware of the complexity and high-risk nature of these patients and, ideally, CTO angioplasty in such patients should be performed at expert centers by expert CTO operators," said Stone, who was not associated with this work.

The study, with lead author Michael Megaly, MD, also from the Minneapolis Heart Institute, will be presented as a poster at the virtual American College of Cardiology 2020 Scientific Session Together With World Congress of Cardiology, and was published online March 16 in JACC: Cardiovascular Interventions.

Clinical Implications

Although the meta-analysis only looked at four studies, which were all observational, nevertheless it included more than 8000 patients, of whom about a quarter had undergone previous CABG.

Their findings have several important clinical implications, according to the researchers. First, "in patients with multivessel disease, ensuring that lesions need bypass via invasive physiological or imaging assessment is strongly recommended," they write.

This means that because there is a good chance of developing chronic occlusion, particularly upstream, in multivessel disease, it may be best not to bypass nonsignificant lesions to start with, Brilakis said.

Second, "because the longevity of [saphenous vein grafts] is not guaranteed, CTO PCI of the native vessel might be unavoidable, and is associated with worse outcomes," they write. A vein graft has a lifespan of 5 to 10 years, Brilakis added.

Last, the study suggests that consideration of full arterial grafts or upfront PCI to the native right coronary artery or circumflex artery in combination with arterial grafting of the left anterior descending artery "might be favorable solutions and should be further studied," the researchers conclude.

Stone draws four similar clinical implications from the new results. First, the findings suggest that "we should preferentially use grafts that are going to have long-term patency rates, and arterial grafts are favored over saphenous vein grafts, particularly the left ventricular mammary artery."

Second, "rather than bypassing vessels with saphenous vein grafts, we might want to consider a hybrid approach where, for example, in complex disease, a left ventricular mammary artery is placed in the left anterior descending artery and then PCI is performed of the right coronary artery and/or circumflex."

Third, closer surveillance may be warranted after bypass surgery "to try to detect vein graft failure, in particular, before you get total occlusion of the proximal segment to try to make percutaneous therapies more effective and safer — although the utility of that is speculative."

Last, Stone reiterated that "if you are going to attempt chronic total occlusion angioplasty in the postbypass patient, recognizing that these are often more complex, more challenging lesions, perhaps the majority should be performed by the true CTO experts who have high success rates and are able to avoid and manage complications when they occur."

CABG Preferred

Although CABG is the preferred revascularization type in patients with highly complex anatomy, it leads to accelerated atherosclerosis proximal to the bypass graft touchdown.

And CTO, which can be challenging to treat, occurs in up to 46% of bypassed native arteries.

To compare in-hospital outcomes of CTO PCI in patients with and without previous CABG, the researchers performed a meta-analysis of four observational studies of patients who were enrolled from 1999 to 2018.

The meta-analysis involved 8131 patients (with 8544 lesions), 2163 (with 2236 lesions) of whom had undergone previous CABG, and the other 5968 (with 6308 lesions) who had not.

The patients with previous CABG were older (68 vs 64 years) and more were male (87% vs 84%).

They had more complex lesions (J-CTO score, 2.7 vs 2.0), more calcified lesions (66% vs 41%), and more lesions longer than 20 mm (67% vs 50%), and their target CTO vessel was more likely to be the right coronary artery (55% vs 51%) or the circumflex artery (27% vs 19%; < .001 for all).

In the patients who had undergone previous bypass, CTO PCI was more often done using a retrograde approach (35% vs 22%), with more contrast volume and longer fluoroscopy time, and was associated with a lower technical success rate (81% vs 87%; P < .001 for all).

In-hospital outcomes after CTO PCI were consistently worse in patients who had undergone previous CABG.

Rates of in-hospital mortality, coronary perforation, and myocardial infarction after CTO PCI were worse in patients with than without previous CABG (odds ratios [OR], 2.8, 2.1, and 2.5, respectively).

However, rates of acute cerebrovascular events and vascular complications were similar in the two groups, and there was a lower incidence of cardiac tamponade in the group with previous CABG.

The study received no outside funding. Brilakis receives consulting/speaker honoraria from Abbott Vascular, American Heart Association (associate editor of Circulation), Biotronik, Boston Scientific, Cardiovascular Innovations Foundation (board of directors), CSI, Elsevier, GE Healthcare, InfraRedx, Medtronic, Siemens, and Teleflex; as well as research support from Regeneron and Siemens; and has shares in MHI Ventures. The disclosures of the other authors are listed with the article. Stone reports relationships with various drug and device companies but no disclosures relevant to this work.

American College of Cardiology (ACC) 2020 Annual Scientific Session/World Congress of Cardiology. Poster. Released March 16, 2020.

JACC: Cardiovasc Imaging. Published online March 16, 2020. Abstract

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