OAT: No Clinical Relevance for CTO Recanalization

Caution urged when considering revascularization in diabetic patients with multivessel occlusions.

The results of the Occluded Artery Trial (OAT) may have little to no clinical relevance for CTO revascularization because the patient population did not meet traditional requirements for PCI or recanalization.

Jeffrey W. Moses, MD, of the Columbia University Medical Center, said the “OAT population did not have any indication for PCI, even if the occlusion was chronic, so any allusion to the relevance of them in the rationale of CTO recanalization … would be specious.”

Lacking qualifications

The OAT population included patients who were relatively young (average age, 58 years) and stable (83% were class I). Twenty percent were being treated with thrombotic therapy and, on average, 8 days passed between MI and randomization to either PCI with medical therapy or medical therapy alone (Figure). 

Ninety percent of the 2,166 patients were nonischemic and 82% had single-vessel disease, 50% in the right coronary artery. These patients did not have chronic occlusions.

The trial has no clinical relevance about the prognostic impact of CTO with acute MI and multivessel disease, Moses said. More chronic patients may have been treated outside of the trial.

One investigator reported that his center “opened those patients that we thought should be opened, and any patients left went into OAT.”

Caution needed

Moses urged caution about performing a revascularization procedure under certain conditions, especially in diabetic patients with multivessel occlusions, proximal left anterior descending, and multiple CTOs.

If there is any combination of a long, tortuous CTO, heavy calcium, poor distal visualization, and no prospect of retrograde approach, “you should really think twice about revascularization,” he added.

The relief of symptoms is the “strongest current indication for CTO with angiography,” said Angela Hoye, MB, ChB, PhD, of the Erasmus Medical Center, Rotterdam, The Netherlands. Successful CTO recanalization allowed 87.4% of patients to live free of CABG for 5 years compared with 61.5% of those with unsuccessful recanalization, she said referring to a recent study published by her group in the European Heart Journal.

Hoye and colleagues found significant differences in survival in successful and unsuccessful CTO procedures. Overall, 93.5% of patients with successful PCI survived for 5 years compared with 88.0% of those with unsuccessful PCI. In patients with multivessel occlusions, the difference was greater: 92.5% of patients who had successful procedures survived to 5-year follow-up compared with 86.3% of those who underwent unsuccessful procedures.

“We can’t underestimate the importance of complete revascularization,” Hoye said. “The survival rate for patients treated successfully is similar to that for patients who do not have a CTO and undergo angioplasty.”