Right Coronary CTO Forecasts Mortality After Left Main PCI

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Chronic total occlusion (CTO) of the right coronary artery, found in nearly a quarter of patients undergoing percutaneous coronary intervention (PCI) for unprotected left main disease, significantly predicts both short and long-term cardiac mortality. The findings were published online June 24, 2011, ahead of print in the Journal of the American College of Cardiology.

David Antoniucci, MD, of Careggi Hospital (Florence, Italy), and colleagues conducted a prospective registry of 330 consecutive patients undergoing PCI for unprotected left main disease between January 2004 and December 2009. Right coronary artery CTO was found in 24% of patients, while another 7% had CTO of the left anterior descending artery and 5% had CTO of the left circumflex artery.

The study population included patients with stable disease and NSTE ACS irrespective of coronary anatomy, with the majority of subjects classified as being at high surgical risk (EuroSCORE > 6). Patients with right coronary CTO tended to be at higher surgical risk and have lower LVEF compared with other patients. They also were more likely to have severe disease of both the left anterior descending artery and circumflex artery. Eight patients had double CTO.

In all, 77% of patients had complete revascularization. A higher percentage of patients who lacked right coronary CTO had complete revascularization compared with those who had the condition (88% vs. 44%; P < 0.001). Right coronary CTO patients had increased cardiac mortality at 6 months as well as poorer cardiac survival at 3 years than did other subjects (table 1).

Table 1. Short- and Long-term Outcomes

Multivariable analysis showed that the only 2 independent predictors of 3-year cardiac mortality were right coronary CTO (HR 2.15; 95% CI 1.02-4.50; P = 0.043) and EuroSCORE (HR 1.03; 95% CI 1.02-1.05; P < 0.001). After propensity score adjustment, right coronary CTO retained its influence on cardiac mortality (HR 2.37; 95% CI 1.09-5.15; P = 0.029).

Notably, CTO PCI was only attempted in half of the patients that had the condition in their right coronary artery; the procedure was successful in 90% of these 39 subjects. Reasons for not performing PCI to treat right coronary CTO included:

• No evidence of a significant area of viable myocardium in the territory by the right coronary artery (n = 20)
• Renal insufficiency contraindicating the use of a large amount of dye (n = 7)
• Low likelihood of PCI success as evaluated by the operator (n = 12)

Complete Revascularization Required

Dr. Antoniucci said that, put simply, right coronary occlusion is a frequent finding in patients with unprotected left main disease and has a strong impact on long-term cardiac mortality. “The goal of percutaneous coronary intervention should be a complete revascularization with the routine treatment of CTO in the majority of patients,” he told TCTMD in an e-mail communication.

According to Dr. Antoniucci, this research does not imply that PCI is ill advised in patients with right coronary CTO. Because no cause-and-effect relationship, only an association, was found between right coronary CTO and mortality, he said he would still recommend PCI in these patients “on the condition that the territory supplied by the right coronary is viable and that PCI includes the treatment of the CTO.”

In a telephone interview, Jeffrey W. Moses, MD, of Weill Cornell Medical College (New York, NY), agreed the underlying message is that interventional cardiologists cannot leave major territories behind, thus putting patients at risk.

“It is not about right coronary total occlusion being worse,” he said. “If you look at those patients who got recanalized vs. those that didn’t, the mortality is [cut] in half.” The study found 6-month cardiac mortality rates of 8.6% in patients with successfully treated right coronary artery CTO and 16.3% in patients with untreated coronary artery CTO or failed right coronary artery CTO PCI (P = 0.311).

“Most sophisticated interventionalists realize that if you had a major vessel like the right that is totally occluded and a left main lesion, that you would not leave the right alone. It is a major vessel, and you can’t leave it behind. It is a bad idea whether you are an interventionalist or a surgeon,” Dr. Moses emphasized.

Treating Patients in the Real World

In their discussion, Dr. Antoniucci and colleagues list the lack of a surgical comparison group as a limitation of this study. A surgical group “would have allowed the assessment of the value of revascularization of occluded vessels for which a PCI attempt was deemed not indicated,” they write.

Both Drs. Antoniucci and Moses agreed that the next step for this research must be randomized clinical trials exploring PCI vs. surgery in a more diverse patient population.

“Ongoing randomized clinical trials are focused on patients with low anatomic complexity, and the SYNTAX trial population was far from ‘real-world’ [unprotected left main disease] patients,” Dr. Antoniucci said. Only 10% of SYNTAX trial patients had a right coronary CTO, he pointed out, and complete revascularization was achieved in only 64.5%.

“Future studies should focus on highly complex anatomy and also high surgical risk patients, since this is the expected scenario in the [coming] years where it’s likely that PCI will perform better than surgery,” Dr. Antoniucci urged.

 

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Source:
Migliorini A, Valenti R, Parodi G, et al. The impact of right coronary artery chronic total occlusion on clinical outcome of patients undergoing percutaneous coronary intervention for unprotected left main disease. J Am Coll Cardiol. 2011;Epub ahead of print.

 

 

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