Better outcomes for STEMI patients with transradial PCI approach

In STEMI patients, the transradial approach to PCI results in fewer episodes of bleeding and lower risk of in-hospital mortality than femoral access PCI, despite a longer door-to-balloon time, according to a recent observational study by Dmitri V. Baklanov, MD, of Saint Luke’s Mid-America Heart Institute in Kansas City, Mo., and colleagues.

Bleeding is a frequent complication of PCI, and bleeding occurs most frequently at the vascular access site. According to several studies, transradial PCI (TRI) is associated with lower rates of post-procedural bleeding (Am J Cardiol 2009;103:796-800, Am Heart J 2009;157:132-40, JACC Cardiovasc Interv 2008; 1:379-86); however, these studies did not include STEMI patients, for whom door-to-balloon time and procedure time are critical to procedural success.

The researchers used the National Cardiovascular Data Registry (NCDR) CathPCI Registry to select STEMI patients who had undergone primary PCI or rescue PCI between Jan. 1, 2007, and Sept. 30, 2011. After exclusions based on cardiac history and insufficient data to determine bleeding risk and in-hospital mortality, the final study sample comprised 90,987 patients from 541 sites. The primary endpoint was in-hospital mortality with secondary endpoints of procedural success and bleeding.

The researchers calculated the percentage of TRI out of all PCI for STEMI for each quarter to assess the temporal trends in TRI. They found that TRI increased but remained little used: from less than 1 percent in the first quarter of 2007 to 6.4 percent in the third quarter of 2011.

There were differences in the characteristics of patients receiving TRI versus PCI. The TRI patients younger, heavier, more likely to be male, white, have peripheral vascular disease and recent heart failure, and were less likely have prior MI, PCI, CABG or be on hemodialysis.  

There were procedural differences, as well. Although the TRI patients received a lower volume of contrast, their fluoroscopy times were longer. There was no difference in the use of stents between the two groups but insertion of intra-aortic balloon pumps occurred more frequently with PCI patients, and these patients also were more likely to receive bivalirudin and glycoprotein IIb/IIIa inhibitors. Median door-to-balloon time was four minutes longer in the TRI patients, but there was no difference in the procedural success rate between the two groups.

The TRI patients had fewer vascular complications requiring procedural care (0.13 percent vs. 0.49 percent in the PCI group). TRI was associated with a lower risk of bleeding (odds ratio 0.62) and lower risk of in-hospital mortality (odds ratio 0.76). The number to treat with TRI to prevent one bleeding event was 25, and number to treat to prevent one death was 207.

The researchers postulated that “the risk associated with major bleeding after STEMI may be greater than that conferred by a four-minute increase in door-to-balloon time.” They also suggested that the reduced stress of TRI and the ability to ambulate immediately post-procedure may be factors in the improved outcomes of TRI patients. Baklanov et al noted the relative rarity of the transradial approach despite the documented benefits, and attributed this to “concerns about the difficulty with radial access, navigation of the tortuous arm vasculature to engage the coronary arteries and inability to use larger thrombectomy catheters.”   

The authors acknowledged that observational studies cannot demonstrate causality. They denoted the possibility of unmeasured confounding and the underreporting of bleeding events and complications other than mortality as other limitations.

The Journal of the American College of Cardiology published the study online Dec. 19.