A study investigating the relationship between systolic blood pressure (BP) reduction and outcome of mechanical thrombectomy has shown that systolic BP, in the first 24 hours after successful reperfusion, is inversely associated with poor outcome. Regardless, the authors, Mohammad Anadani and Alejandro Spiotta from the Medical University of South Carolina, Charleston, USA and colleagues report no association between systolic BP and safety outcomes.
They explain: “Many studies investigating the relationship between BP and outcome after mechanical thrombectomy have reported a significant association between higher BP and poor outcome. However, the relationship between systolic BP reduction and outcome of thrombectomy has not been studied.” Anadani and team also posit that due to a lack of randomised trials, there is no consensus on the best approach for BP control following thrombectomy. Thus, the team set out to investigate the association between systolic BP reduction and clinical outcomes after successful reperfusion via thrombectomy in a large multicentre study.
Carried out at 10 comprehensive stroke centres, patients with acute ischaemic stroke and anterior circulation large vessel occlusion (LVO) who achieved successful reperfusion were included. A total of 1,361 patients were include in the final analysis.
According to Anadani et al, systolic BP reduction as a continuous variable was inversely associated with poor outcome (OR: 0.97; 95% CI 0.95–0.98; p<0.001), but not with the safety outcomes. The subanalysis, based on reperfusion status, demonstrated that systolic BP reduction was associated with lower odds of poor outcome, but only in patients with complete reperfusion (modified Thrombolysis in Cerebral Infarction [mTICI 3]).
The investigators further divided systolic BP reduction into categories: <1%, 1–10%, 11–20%, and >20%, to understand the shape of the relationship between systolic BP reduction and outcome. “Poor outcome was more common in the first group, a finding that is probably due to a significant increase in the systolic BP in the first 24 hours in the first group,” they write. Given that the odds of poor outcome were lower in the other three groups than the first, the authors postulate that preventing an increase in systolic BP is probably more important than reducing systolic BP in the first 24 hours after successful recanalisation.
Anadani and colleagues point to the fact that the current study differs from those previously published in three main aspects. First, a homogenous group of patients with a “relatively similar” recanalisation status and location of occlusion were included. Second, the authors were able to account for admission ASPECTS (Alberta Stroke Program Early CT Score) as a “surrogate” for initial infarct volume. And lastly, they write: “Our study was significantly larger [than others], allowing for robust statistical analysis. These differences could explain, at least in part, the inconsistencies between our results and those of previous studies.”
Speaking to NeuroNews, Anadani says, “Blood pressure reduction to less than 160 or 140 mmHg after mechanical thrombectomy is a common practice despite the lack of randomised trials to support the safety or efficacy of such practice. Our study provides preliminary evidence that BP reduction is safe after thrombectomy and maybe beneficial. However, prospective studies are needed to validate our findings and ultimately the optimal BP goal can only be determined by a prospective randomised trial.
“We should point out that our study included only patients with successful recanalisation, therefore, our results should not be applied to patients with unsuccessful recanalisation.”
The mean age of the cohort was 68 (SD=15) years and 50% of the patients were female. Median onset-to-groin time was 216 minutes (IQR=174), while mTICI 3 was achieved in 54% of the patients. Further, mean admission systolic BP was 143mmHg. In terms of post-procedural outcome, a total of 703 (52%) of patients had poor outcome at 90 days, and symptomatic intracerebral haemorrhage occurred in 5%, with a hemicraniectomy performed in 4% of patients. Of note, the authors write that that systolic BP reduction was calculated using the formula: 100x ([admission systolic BP–mean systolic BP]/admission systolic BP).