Long-Term Outcome as Function of Blood Pressure in Acute Ischemic Stroke and Effects of Thrombolysis

Baseline blood pressure does not modify the effect of intravenous thrombolysis in successfully revascularized patients

Background

Studies indicate a trajectory relationship between baseline blood pressure (BP) and outcome in patients with acute ischemic stroke (AIS) eligible for both intravenous thrombolysis (IVT) with alteplase and endovascular treatment (EVT). We determined whether baseline BP modified the effect of IVT in successfully revascularized AIS patients who participated in the Direct Intra-Arterial Thrombectomy to Revascularize AIS Patients With Large Vessel Occlusion Efficiently in Chinese Tertiary Hospitals (DIECT-MT) trial.

Methods

The association of baseline systolic BP, trichotomized as high (141–185 mmHg), middle (121–140 mmHg), and low (91–120 mmHg), and the outcomes of any intracerebral hemorrhage (ICH), symptomatic ICH (sICH), and mortality and functional outcome on the modified Rankin scale at 90 days were explored. Logistic regression models determined the interaction between clinical outcomes and baseline systolic and diastolic BP, and mean arterial pressure (MAP), at 10 mmHg intervals. Data are reported as odds ratios (OR) and 95% CI.

Results

A post-hoc analysis of DIRECT-MT, in 510 of the 656 randomized participants with successful revascularization underwent MT. The overall adjusted common OR of IVT and baseline BP on any ICH, sICH, and 90-day mortality and functional outcome were 0.884 (95%CI 0.613–1.274), 0.643 (95%CI 0.283–1.458), 0.842 (95%CI 0.566–1.252), and 1.286 (95%CI 0.772–2.142), respectively. No significant interaction between baseline blood pressure and intravenous thrombolysis with clinical outcome was observed.

Conclusions

In patients with baseline SBP under 185 mmHg, baseline blood pressure does not alter the risk of hemorrhagic transformation and clinical

outcome in successfully revascularized patients, regardless of intravenous alteplase usage. Future studies are needed to confirm our findings.

Registration

URL: http://www.clinicaltrials.gov, Identifier: NCT03469206.

Effects of Baseline Systolic Blood Pressure on Outcome in Ischemic Stroke Patients With Intravenous Thrombolysis Therapy: A Systematic Review and Meta-Analysis

BACKGROUND

Baseline systolic blood pressure (SBP) is an important parameter that can significantly influence the outcome in ischemic stroke patients who received intravenous thrombolysis, but the target baseline SBP for optimal outcome is uncertain. This study aimed to assess the relationship between baseline SBP and outcome.

MATERIALS AND METHODS

Studies that evaluated the association between the baseline SBP and the outcome of patients undergoing thrombolytic therapy were sought. Data were extracted according to a predefined data extraction form and then analyzed by STATA 12.0 software. The primary endpoint was the occurrence of good outcomes measured by a modified Rankin Scale score at 3 months, while the secondary endpoint was the occurrence of intracranial hemorrhage and death.

RESULTS

Eleven studies involving a total of 33,263 patients were included. Pooled data suggested that the odds of good outcome was decreased by 7% per 10 mm Hg increase in baseline SBP (odds ratio=0.93; 95% confidence interval: 0.91-0.94; P<0.001). Patients with higher baseline SBP were more likely to have intracranial hemorrhage (odds ratio=1.12 per 10 mm Hg increase; 95% confidence interval: 1.08-1.16, P<0.001).

CONCLUSIONS

This study suggested that lower baseline SBP may be positively associated with a greater chance of good outcome and less chance of intracranial hemorrhage. However, this effect was reliable only when the baseline SBP was within a certain range, which has not been explicitly stated. Therefore, more well-designed studies are needed to define the optimal baseline SBP.

Thrombolysis for acute ischaemic stroke

BACKGROUND

Most strokes are due to blockage of an artery in the brain by a blood clot. Prompt treatment with thrombolytic drugs can restore blood flow before major brain damage has occurred and improve recovery after stroke in some people. Thrombolytic drugs, however, can also cause serious bleeding in the brain, which can be fatal. One drug, recombinant tissue plasminogen activator (rt-PA), is licensed for use in selected patients within 4.5 hours of stroke in Europe and within three hours in the USA. There is an upper age limit of 80 years in some countries, and a limitation to mainly non-severe stroke in others. Forty per cent more data are available since this review was last updated in 2009.

OBJECTIVES

To determine whether, and in what circumstances, thrombolytic therapy might be an effective and safe treatment for acute ischaemic stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched November 2013), MEDLINE (1966 to November 2013) and EMBASE (1980 to November 2013). We also handsearched conference proceedings and journals, searched reference lists and contacted pharmaceutical companies and trialists.

SELECTION CRITERIA

Randomised trials of any thrombolytic agent compared with control in people with definite ischaemic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors applied the inclusion criteria, extracted data and assessed trial quality. We verified the extracted data with investigators of all major trials, obtaining additional unpublished data if available.

MAIN RESULTS

We included 27 trials, involving 10,187 participants, testing urokinase, streptokinase, rt-PA, recombinant pro-urokinase or desmoteplase. Four trials used intra-arterial administration, while the rest used the intravenous route. Most data come from trials that started treatment up to six hours after stroke. About 44% of the trials (about 70% of the participants) were testing intravenous rt-PA. In earlier studies very few of the participants (0.5%) were aged over 80 years; in this update, 16% of participants are over 80 years of age due to the inclusion of IST-3 (53% of participants in this trial were aged over 80 years). Trials published more recently utilised computerised randomisation, so there are less likely to be baseline imbalances than in previous versions of the review. More than 50% of trials fulfilled criteria for high-grade concealment; there were few losses to follow-up for the main outcomes.Thrombolytic therapy, mostly administered up to six hours after ischaemic stroke, significantly reduced the proportion of participants who were dead or dependent (modified Rankin 3 to 6) at three to six months after stroke (odds ratio (OR) 0.85, 95% confidence interval (CI) 0.78 to 0.93). Thrombolytic therapy increased the risk of symptomatic intracranial haemorrhage (OR 3.75, 95% CI 3.11 to 4.51), early death (OR 1.69, 95% CI 1.44 to 1.98; 13 trials, 7458 participants) and death by three to six months after stroke (OR 1.18, 95% CI 1.06 to 1.30). Early death after thrombolysis was mostly attributable to intracranial haemorrhage. Treatment within three hours of stroke was more effective in reducing death or dependency (OR 0.66, 95% CI 0.56 to 0.79) without any increase in death (OR 0.99, 95% CI 0.82 to 1.21; 11 trials, 2187 participants). There was heterogeneity between the trials. Contemporaneous antithrombotic drugs increased the risk of death. Trials testing rt-PA showed a significant reduction in death or dependency with treatment up to six hours (OR 0.84, 95% CI 0.77 to 0.93, P = 0.0006; 8 trials, 6729 participants) with significant heterogeneity; treatment within three hours was more beneficial (OR 0.65, 95% CI 0.54 to 0.80, P < 0.0001; 6 trials, 1779 participants) without heterogeneity. Participants aged over 80 years benefited equally to those aged under 80 years, particularly if treated within three hours of stroke.

AUTHORS' CONCLUSIONS

Thrombolytic therapy given up to six hours after stroke reduces the proportion of dead or dependent people. Those treated within the first three hours derive substantially more benefit than with later treatment. This overall benefit was apparent despite an increase in symptomatic intracranial haemorrhage, deaths at seven to 10 days, and deaths at final follow-up (except for trials testing rt-PA, which had no effect on death at final follow-up). Further trials are needed to identify the latest time window, whether people with mild stroke benefit from thrombolysis, to find ways of reducing symptomatic intracranial haemorrhage and deaths, and to identify the environment in which thrombolysis may best be given in routine practice.