Early blood pressure management in the ambulance has no clear benefit for stroke patients, study finds

Recent New England Medical Journal This study evaluated whether early blood pressure control in the ambulance leads to better clinical outcomes in patients with acute undifferentiated stroke.

study: Intensive blood pressure reduction by ambulance in hyperacute stroke. Image credit: Jaromir Chalabala / Shutterstock.com

stroke treatment

Intensive treatment to lower blood pressure levels is often clinically beneficial for patients with acute intracerebral hemorrhage. However, trials aimed solely at lowering blood pressure have produced inconclusive results, which may be due to variations in trial design, population, or intervention. Clinical outcomes are likely to be better if blood pressure-lowering interventions are initiated as early as possible. However, this can be complicated in patients with acute ischemic stroke.

Two trials previously reported similar results. efficacy Safety of prehospital blood pressure lowering interventions within hours of acute stroke. In patients with intracerebral hemorrhage, worse outcomes were observed in patients receiving the glyceryl trinitrate patch compared to those receiving the sham patch.

About this study

The current study reports the results of the Intensive Ambulance-Based Blood Pressure Reduction Trial in Hyperacute Stroke (INTERACT) 4. The aim of INTERACT 4 was to evaluate the effectiveness and safety of starting ambulance-delivered intravenous antihypertensive treatment within 2 hours of acute stroke.

The starting group consisted of patients with suspected acute stroke causing motor dysfunction, elevated systolic blood pressure >150 mmHg, and treated by ambulance within 2 hours of symptom onset. Study participants were randomly assigned to receive usual blood pressure control or immediate intervention to lower systolic blood pressure to the target range of 130 to 140 mm Hg.

The primary safety outcome was the occurrence of serious adverse events. The primary efficacy outcome was assessed by reading the modified Rankin Scale score, with a score of 0 representing no symptoms and a score of 6 representing death. Scores were recorded 90 days after randomization.

research result

The sample included 2,404 patients from China, with an average age of 70 years. The intervention group consisted of 1,205 participants, with a median time interval from symptom onset to randomization of 61 minutes.

Mean blood pressure at randomization was 178/98 mmHg. Imaging tests were performed on 2,204 patients to confirm stroke, and 46.5% of patients were confirmed to have hemorrhagic stroke.

When patients arrived at the hospital, the mean systolic blood pressure measurements in the intervention and usual care groups were 158 mm Hg and 170 mm Hg, respectively. No differences in functional outcomes were observed between the intervention and usual care groups. Furthermore, the incidence of serious adverse events was similar in the two study groups.

Among patients with hemorrhagic stroke, lower prehospital blood pressure was associated with a lower likelihood of poor functional outcome. This relationship was reversed in patients with cerebral ischemia, and an increased risk of poor functional outcome was observed.

strengths and limitations

IMPACT 4's main strength is the provision of emergency medical services physician care. Other strengths include the use of a simple consent process, the ability to lower blood pressure through a simple intravenous treatment regimen, and high rates of protocol compliance.

One limitation is the involvement of physicians in emergency services, which reduces the generalizability of the findings. Furthermore, the current study was conducted in China, where the nature of stroke is different from that in North America and Europe.

For example, North America has a higher rate of ischemic stroke, whereas Europe has a higher incidence of intracerebral hemorrhage. Additionally, intravenous urapidil is not widely available outside of China.

Due to the lack of generalizability, this research approach may be less appropriate for ambulance services run by paramedics or where strokes are caused by mild neurological deficits. . Data quality may also have been compromised by several factors, including quarantine restrictions during the coronavirus disease 2019 (COVID-19) pandemic, open-label design, variability in other medical care, and broad inclusion criteria.

Conclusion

The current study shows that rapid initiation of intensive blood pressure lowering within 2 hours in acute stroke patients has a significant benefit in functional outcome compared with standard care, which begins blood pressure control after arrival at the hospital. It has been proven that this does not occur. In patients with cerebral ischemia and hemorrhagic stroke, interventions may have had mixed effects.