Non-internal carotid artery (non-ICA) site of occlusion, the use of a balloon-guided catheter, and better collateral grade were all independent predictors of the first-pass effect, concluded Ashutosh Jadhav from the University of Pittsburgh, Pittsburgh, USA, at the recent Society of NeuroInterventional Surgery’s (SNIS) annual meeting (22–25 July, Miami, USA).
During his talk, he defined the first-pass effect (FPE) as “having achieved complete revascularisation after a single attempt with mechanical thrombectomy”, and acknowledges that FPE has been “associated with good clinical outcomes in patients presenting with large vessel occlusion”.
According to Jadhav, the concept of the first-pass effect was first described in the NASA registry which was a retrospective study of patients who underwent Solitaire (Medtronic) thrombectomy in North America. In that analysis, the first-pass effect was defined as achieving TICI 2b/3 recanalisation after a single pass.
In comparison, the STRATIS registry was a prospective, non-randomised registry of 984 patient treated at 55 sites. “It afforded us several advantages over NASA,” ascertained Jadhav. “It was prospective, with core lab imaging, and included a larger population of patients.” Results of the study showed that a first-pass effect was achieved in 40% of patients and that rates of mortality at 90 days were lower in the first-pass effect group compared to the non-first-pass effect group (12% vs. 19%, respectively).
Alluding to the baseline characteristics in the STRATIS registry, he said that in patients with first-pass effect and non-first-pass effect, characteristics were comparable across most of the baseline features. However, the presence of an ICA occlusion was much more frequent in the non-first-pass effect population.
“If we look at procedural characteristics, there were no significant differences in the utilisation of IV tPA, onset to arrival and onset to puncture. But, as you would expect, puncture to reperfusion was significantly faster in patients who achieved a first-pass effect,” reported Jadhav.
However, he addressed an important bias in the first-pass literature, “When you compare first-pass effect versus non-first-pass effect populations, you may be looking at patients who did not achieve complete recanalisation. We know that complete recanalisation is a very strong predictor of good outcome.”
Pointing to a table of outcomes, he posited, “The first-pass effect continues to be a strong predictor of good outcome and lower mortality, even when compared to patients who achieved good recanalisation after multiple passes.”
Delving into the multivariate predictors of a first-pass effect, he said that certain patient specific features favour achieving a first-pass effect, such as good collaterals, as well as M1 or M2 as the site of occlusion over ICA as the site of occlusion. “So, the more distal you go with your occlusion, the less clot burden, and the higher the likelihood of a first-pass effect,” Jadhav put forward.
“To summarise, the STRATIS registry shows similar improvements in outcome with a first-pass effect as found in NASA, but it is a much more rigorous study design.” He added that a first-pass effect continues to be associated with better outcomes—even when compared to patients who achieved technical successful outcomes based on recanalisation. Moreover, patient outcomes overall have improved since NASA, which Jadhav attributed to improved devices and techniques.
Finally, he concluded that “by understanding more about the factors that influence a good clinical outcome, we can reach our goal of helping all stroke patients survive and thrive”, as he called for further studies “to maximise the first-pass effect and continue these trends”.