In addition, a benefit of the transradial approach on the incidence of death or myocardial infarction is evident in observational studies but “remains inconclusive” in randomized trials, the researchers say in a report online now in the American Heart Journal.
Despite lower risks of access site-related complications with transradial approach, its clinical benefit for PCI is “uncertain,” Dr. Olivier Bertrand from the Quebec Heart and Lung Institute in Quebec City in Canada and colleagues note in the paper.
To investigate, they identified 15 randomized controlled trials and 61 observational studies that compared transradial approach (TRA) with transfemoral approach (TFA) for PCI in more than 760,000 patients. These contemporary studies were published between 1993 and 2011.
Compared with TFA, TRA was associated with a 78% reduced odds of bleeding (OR 0.22) and an 80% reduced odds of transfusions (OR 0.20). “These findings were consistent in both randomized and observational studies,” the authors say.
Within 30 days after PCI, there was a 44% reduction of mortality with TRA (OR 0.56), although the effect was mainly due to observational studies (OR 0.52, adjusted OR 0.49), with an OR of 0.80 in randomized trials, as mentioned.
Dr. Bertrand and colleagues say their meta-analysis supports two previous meta-analyses – one by Agostoni et al published in Journal of the American College of Cardiology (See Reuters Health story Aug. 6, 2004) and the other by Jolly et al published in the American Heart Journal in 2009.
Both of these analyses found a greater than 70% reduction in entry site complications and major bleeding. The first analysis in 2004 involving 1,155 PCI patients did not suggest a clinical benefit for TRA in terms of major adverse cardiac events, but the second analysis performed in 2009 involving 4,461 patients did suggest a possible advantage for TRA in terms of the composite end point of death, MI, or stroke (OR 0.71).
The authors say, “The mechanism by which a reduction in major bleeding and transfusion could impact survival directly or indirectly remains an open question. Major bleeding can lead to death through direct (eg, retroperitoneal hemorrhage) or indirect (eg, cessation of antithrombotic therapy with subsequent increase in thrombotic risk) mechanisms.”
They also note that the recently completed (and largest to date) RIVAL randomized trial published in Lancet in 2011 found no significant mortality benefit in the overall population but a statistically significant reduction in mortality with TRA in patients undergoing primary PCI for acute ST-segment elevation MI. “Thus, it may well be that maximum benefit for TRA can be found in higher risk population (with high rate of PCI).”
And in the RIFLE-STEACS trial — reported during a Late-Breaking Clinical Trial Session at the TCT [Transcatheter Cardiovascular Therapeutics] 2011 conference in San Francisco — a significant reduction in cardiac death from 9.2% in the TFA group to 5.2% in the TRA group (p=0.020) was observed.
“Because the benefit for TRA seems also linked to the experience of the centers, it appears logical from a health perspective to continue promoting education in TRA to expand the number of sites proficient with TRA techniques,” the authors say.
In addition, they note that several randomized trials comparing TRA with TFA are ongoing.