Performing transradial primary percutaneous coronary intervention (PCI) without complete diagnostic angiography cuts door-to-balloon (D2B) time without adding risk, according to a Canadian study published online January 14, 2013, ahead of print in the American Journal of Cardiology.

Investigators led by Olivier Bertrand, MD, PhD, of the Quebec Heart and Lung Institute (Quebec City, Quebec), retrospectively analyzed D2B times and clinical outcomes for 1,900 STEMI patients who underwent transradial PCI within 12 hours of symptom onset. They separated the cohort into 2 arms according to whether patients received:

• Complete diagnostic angiography before PCI (n = 1,338)
• Immediate PCI with only angiography of the culprit vessel and contralateral angiography after the procedure (n = 562)

There were no significant differences in the baseline characteristics of the 2 groups.

Patients who proceeded to immediate transradial PCI experienced lower median D2B times than their peers who underwent complete diagnostic angiography. A greater proportion of the immediate PCI group also achieved D2B times within 60 and 90 minutes (table 1).

Table 1. Treatment Times

However, clinical outcomes did not differ between the 2 approaches (table 2).

Table 2. Clinical Outcomes

Cutting to the Chase

“The classical view is that first you get access and then you do a complete angiogram—you look at the left and the right systematically—and then you proceed with the PCI,” Dr. Bertrand told TCTMD in a telephone interview. His research group challenged the orthodoxy, suggesting instead that time is more important than full diagnosis. “Whatever the anatomy,” he said, “at the time of a STEMI, you want the operator to dilate the lesion and then reassess the patient for other lesions later.” 

Another message from the study, Dr. Bertrand noted, is that radial PCI is by no means slower than femoral. "We have been in the desert for 7 or 8 years," he said, "trying to convert US physicians to a better access site." The data in this study prove that excellent transradial D2B times can be achieved, he stressed.

In a telephone interview, Ian C. Gilchrist, MD, of Penn State Hershey Heart and Vascular Center (Hershey, PA), commended the researchers. With STEMI patients, he said, “you have a pretty good idea of which artery is involved, and time is of the essence. So they are going where the money is up front and looking at the rest of it afterwards.” These investigators, he continued, “are showing us that there is room to rethink how we do our procedures.”

The emphasis on a complete angiogram, Dr. Bertrand said, is based on operators worrying that, though they may locate the culprit occlusion on ECG, they may find another lesion later. “And you will say, ‘Oh my God, I should have sent [the patient] for surgery.’”

But the study observed no extra CABG surgeries or elective PCIs of non-infarct-related lesions to suggest that operators had rushed too much. “There is no penalty if we fix the lesion first and then finish with the [complete] angiogram,” Dr. Bertrand concluded, “but it is a very easy way to cut down your D2B time.”

Dr. Gilchrist also noted that, while this particular study was not powered to show a significant reduction in clinical endpoints, many studies have shown that an improvement in D2B time is correlated with less mortality.

Different MIs Call for Different Approaches 

In an e-mail communication, Sunil V. Rao, MD, of Duke University Medical Center (Durham, NC), stressed that to attempt PCI without a complete diagnostic angiogram, operators must be relatively certain of where the culprit lesion is.

“You would need to be confident that there is ST-segment elevation and that the leads that show it are clearly localizing,” he said. “One can say confidently that anterior ST-segment elevation [indicates] the left anterior descending artery. Inferior ST-segment elevation is often the right coronary artery, but sometimes can be a low branch of the left circumflex.”

Dr. Bertrand also mentioned that the left circumflex can be a problem, because it is often hard to diagnose from the ECG. These differences in diagnostic certainty probably lead to different approaches in the cath lab. In the study, patients with a culprit lesion in the left anterior descending artery were more likely to have immediate PCI.

Different diagnoses also necessitate different priorities, said Dr. Bertrand. “When operators saw a large anterior MI, they would go directly for treatment,” he said. “These anterior MIs are the large, acute MIs and are where you want to open the vessel as quickly as possible.” On the other hand, he noted, inferior MIs are often smaller and thus give the operator more time to consider options and perform angiography.

Dr. Bertrand also suggested that, if the procedure was performed by a fellow with a primary operator overseeing, they were probably more likely to do a complete angiogram first. Though the study did not collect such data, these selection biases, he said, are important to remember when assessing the results.

 

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Source:
Plourde G, Abdelaal E, Bataille Y, et al. Effect on door-to-balloon time of immediate transradial percutaneous coronary intervention on culprit lesion in ST-elevation myocardial infarction compared to diagnostic angiography followed by primary percutaneous coronary intervention. Am J Cardiol. 2013;Epub ahead of print.

 

 

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• Short D2B Times Have Greater Mortality Impact on STEMI Early Presenters
• US Registry Data Support Wider Adoption of Transradial PCI in STEMI Patients 
• AHA Database: Door-To-Balloon Times Improve, Still Not Ideal