PARIS (FRONTLINE MEDICAL NEWS) – Eighty-eight percent of chronic total occlusions (CTOs) in a large series of patients undergoing coronary artery bypass graft surgery were successfully bypassed using arterial conduits with durable patency.

“Bypass graft surgery using arterial grafts is an acceptable modality of treatment for patients with CTOs and perhaps can be a benchmark against which PCI [percutaneous coronary intervention] for CTOs should be measured,” Teresa May Kieser, MD , said at the annual congress of the European Association of Percutaneous Cardiovascular Interventions.

An important caveat: It’s vital that surgeons strive for complete revascularization in these patients. In her study, incomplete revascularization in patients with one or more CTOs was associated with a 2.3-fold increased risk of operative mortality, compared with that of completely revascularized patients with a CTO. In contrast, in patients without CTOs, incomplete revascularization didn’t affect operative mortality.

“We have previously shown in another paper that arterial grafting mitigates the adverse effect of incomplete revascularization,” said Dr. Kieser, a cardiothoracic surgeon at the University of Calgary (Alt.).

In recent years, treatment of CTOs has increasingly drawn the attention of interventional cardiologists. Dr. Kieser presented what she thinks is the first study of coronary artery bypass graft (CABG) surgery for management of CTOs. It included 1,333 consecutive CABG patients with a total of 3,906 bypasses, a whopping 98% of which were arterial grafts, with a mean of 2.9 grafts per patient. Eleven percent of the CABGs were done emergently, 48% urgently, and 41% electively.

The key epidemiologic finding to emerge from the study is that CTOs are quite common in CABG patients. In this series, 47% of CABG patients had a mean of 1.35 chronically occluded coronary arteries.

Of 843 CTOs in three major territories, 88% were able to be bypassed. All of the 246 CTOs in the left anterior descending coronary artery were able to be bypassed, as were 84% of 415 CTOs in the right coronary artery and 85% in the circumflex system.

The CTO group as a whole had significantly greater impairment of left ventricular function. Thirty-seven percent of them had an ejection fraction of 30%-50%, compared with 22% of the non-CTO patients. The 10% prevalence of an left ventricular ejection fraction (LVEF) below 30% in the CTO group was twice that of the non-CTO group. The CTO group was also significantly more likely to undergo incomplete revascularization, by a margin of 21% versus 5.7%.

Operative mortality was 3.7% overall and just 0.55% in the elective CABG patients. In a multivariate logistic regression analysis controlled for surgical urgency, incomplete revascularization, and EuroSCORE risk, operative mortality didn’t differ significantly between the CTO and non-CTO groups.

However, in the presence of CTOs, incomplete revascularization was associated with an 11.6% operative mortality, compared with a 2.8% rate in fully revascularized CTO patients.

A total of 110 patients with bypassed CTOs underwent symptom-driven follow-up coronary angiography at a median of 3.6 years after CABG. Reassuringly, CTO graft patency was noted in 95% of the LAD grafts, 92% of the right coronary artery grafts, and 79% of the circumflex grafts.

Dr. Kieser’s audience of interventional cardiologists was clearly bowled over by her results, not only the high rate of successful surgical bypass of CTOs, but also by her use of arterial grafts 98% of the time.

“This is my personal practice,” she explained. “I just believe in arterial grafting so much. They perform best in CTO arteries because of their lack of competitive flow.”

Session chair Oliver Gämperli, MD , of University Hospital Zurich, commented, “We are very concerned about patency rates, and you showed us fantastic patency rates. This is much better than what we’re used to with saphenous vein grafts. I think we need to talk to our surgeons and try to get them to do more arterial grafts of CTOs.”

It’s worth noting that in the CTO subgroup from the landmark randomized SYNTAX trial, the complete revascularization rate was only about 50% in the PCI group, compared with nearly 65% in the CABG group, he added.

Asked why a cardiac surgeon wouldn’t bypass a CTO, Dr. Kieser rattled off several technical reasons, including a vessel size of less than 1 mm, diffuse disease, extensive scar, or an inaccessible location. But that’s not the whole story, she added. She has heard surgical colleagues say, “The patient doesn’t need that artery, he’s learned to live without it.” That burns her up.

“Patients need every artery in the heart, and the one with a CTO is the best one for an arterial graft because it almost cannot fail, especially to the left anterior descending artery. I think we have to change the mentality of the surgeons to ‘If it can be done, it should be done,’ ” Dr. Kieser said.

She reported having no financial conflicts of interest regarding her study.