MERCI Registry Outcomes Mirror Trial Results
Overall in the registry, 80% of patients were successfully recanalized, which was significantly more than in the two MERCI trials combined (65%). Similar numbers of patients had good 90-day outcomes (32% in both the registry and combined trials). Mortality at 90 days also was not significantly different between the registry and the trials (33% and 38%).
Symptomatic brain hemorrhage in the registry was 7% overall, not significantly different from the 8.8% seen in the MERCI trials, Dr. Rymer said. “It is notable that in the patients who were well recanalized (those with a TICI grade of 2b to 3), the symptomatic hemorrhage rate was lower (3.7% in TICI 2b and 5.4% in TICI 3).”
When the investigators examined the rate of good 90-day outcome (defined as an mRS of 0–2), they found the best outcomes in patients with the lowest baseline NIHSS scores. “As the stroke became more severe, the likelihood of good outcome went down,” she said. In cases with NIHSS scores lower than 16, “the outcomes were excellent,” she said, with up to 70% of those with a TICI grade of 2b or 3 experiencing a good outcome. TICI 2a provided only modest benefit, but it was consistent across the whole range of NIHSS scores, she added.
Age and recanalization status also affected mortality. “Age was a predictor of worse outcome, but recanalization did provide benefit across all ages except for the very young, who had low mortality rates in any case,” she said.
A multivariate analysis identified several factors that significantly affected mortality both negatively and positively, including advancing age (odds ratio, 1.05); worse baseline NIHSS score (OR, 1.08); revascularization to a TICI grade of 2a, 2b, or 3 (OR, 0.33); heart failure (OR, 2.85); blood glucose above 140 mg/dL (OR 2.0); and intubation during the revascularization procedure (OR, 2.20)
The same multivariate model also identified factors that negatively impacted good 90-day outcomes, including worse baseline NIHSS score (OR, 0.88), advancing age (OR, 0.96), intubation during the procedure (OR, 0.43), longer duration of procedure (OR, 0.66), and a blood glucose level of 140 mg/dL or greater (OR, 0.59).
During the discussion period, several audience members questioned the relationship between intubation and poor outcomes. Dr. Joseph Broderick, chair of the department of neurology at the University of Cincinnati, said that the intubation data were interesting but could throw a statistical kink into the risk analysis. “There is always a risk of selection bias unless you compare the [sites] that always intubated against those that did not. Otherwise, you might be including people who were intubated because they looked dead, had heart failure, or weren't breathing.”
“We don't know what all the facts are” in relation to intubation, Dr. Rymer said. “We can only speculate.”
