Highlights
Prognostic Value of Trajectories
Distinct systolic blood pressure (SBP) patterns over the first 24 hours after an acute intracerebral hemorrhage (ICH) are significantly associated with 90-day functional outcomes, providing more nuanced prognostic information than single-point measurements.
Risks of Persistent Hypertension
Patients categorized in the ‘high’ and ‘high-to-moderate’ SBP trajectory groups faced the greatest risk of death or severe disability, with adjusted odds ratios for poor outcomes reaching as high as 1.90.
The ‘Low’ Trajectory Advantage
Consistent, moderate SBP control—classified as the ‘low’ trajectory in this analysis—was associated with the highest probability of functional recovery (mRS 0-2), reinforcing the need for stable hemodynamic management.
Background: The Dilemma of SBP Management in ICH
Acute intracerebral hemorrhage (ICH) remains one of the most devastating forms of stroke, characterized by high mortality and significant long-term disability. For decades, the management of systolic blood pressure (SBP) has been a cornerstone of acute ICH care, aimed at limiting hematoma expansion. However, the optimal speed, depth, and duration of SBP lowering have remained subjects of intense clinical debate.
While the INTERACT2 trial suggested that intensive SBP lowering (target 200 mm Hg to <140 mm Hg within a single hour—might negate the neuroprotective effects. This study seeks to move beyond static targets, analyzing the 'trajectory' of SBP over the first 24 hours to identify the most favorable patterns for patient recovery.
Study Design and Methodological Rigor
This study represents a robust pooled analysis of individual patient-level data from five landmark trials: the four Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial (INTERACT) studies and the second Antihypertensive Treatment of Acute Cerebral Hemorrhage (ATACH-II) trial.
Population and Methodology
A total of 11,269 patients were included (10,269 from INTERACT; 1,000 from ATACH-II). The mean age was 62.4 years, and 36.4% were female. To analyze the SBP patterns, researchers employed Latent Class Analysis (LCA), a statistical technique that groups patients based on the similarity of their SBP measurements over the first 24 hours (using 9 specific time points).
Primary Endpoints
The primary outcome was functional recovery at 90 days, assessed using the modified Rankin Scale (mRS). Poor functional outcome was defined as an mRS score of 3 to 6 (ranging from moderate disability to death). The analysis adjusted for baseline covariates including age, sex, baseline SBP, stroke severity (NIHSS score), and hematoma volume.
Decoding the Six Trajectories: Key Results
The LCA identified six distinct SBP trajectories: low, moderate-to-low, moderate, high, high-to-moderate, and high-to-low. These trajectories reflect the real-world variability of blood pressure response to treatment in the acute phase.
Association with Functional Outcomes
In the INTERACT cohort, there was a clear and significant trend (p = 0.04) showing that as the SBP trajectory moved from ‘low’ to ‘high,’ the odds of a poor functional outcome increased. Taking the ‘low’ SBP group as the reference, the adjusted odds ratios (aOR) for poor outcomes were as follows:
1. Group 2 (Moderate-to-low): aOR 1.16 (95% CI 0.98–1.37)
2. Group 3 (Moderate): aOR 1.44 (95% CI 1.18–1.75)
3. Group 4 (High): aOR 1.46 (95% CI 1.15–1.87)
4. Group 5 (High-to-moderate): aOR 1.90 (95% CI 1.32–2.73)
5. Group 6 (High-to-low): aOR 1.28 (95% CI 1.02–1.60)
Validation and Significance
While the ATACH-II cohort showed a similar directional trend, the results did not reach statistical significance, likely due to the smaller sample size (n=1,000) compared to the INTERACT pool. However, the consistency of the ‘high-to-moderate’ group having the worst prognosis across the analysis highlights the danger of sustained hypertension in the acute phase of ICH.
Expert Commentary: Bridging Trial Evidence and Bedside Practice
The findings of this pooled analysis provide Class III evidence that the path SBP takes in the first 24 hours is a potent predictor of recovery. From a clinical perspective, these data suggest that ‘reaching the target’ is only part of the challenge; maintaining stability within that target is equally vital.
One of the most striking findings is the poor performance of the ‘high-to-moderate’ and ‘high’ groups. This suggests that patients who are resistant to initial antihypertensive therapy—often those with underlying chronic hypertensive remodeling or severe autonomic dysfunction following the ictus—are at the highest risk. Conversely, the ‘low’ trajectory group did not represent hypotension, but rather a successful, sustained reduction to the 130–140 mm Hg range, which appears to be the ‘sweet spot’ for most patients.
Physicians should also note the ‘high-to-low’ group. While these patients eventually reached lower SBP levels, the initial period of severe hypertension may have already facilitated hematoma expansion or exacerbated perihematomal edema, leading to an aOR for poor outcome of 1.28.
Study Limitations and Future Directions
Despite the large sample size, several limitations must be considered. First, the analysis is post-hoc and observational in nature, meaning that while associations are strong, causality cannot be definitively proven. Second, the ‘low’ trajectory might partly reflect patients with smaller hematomas or less severe initial injury, although the researchers adjusted for baseline severity. Third, the specific antihypertensive agents used varied across trials and regions, which may influence SBP variability and secondary outcomes like renal function.
Future research should focus on ‘dynamic’ blood pressure management protocols that use real-time trajectory monitoring to adjust titration rates, potentially using artificial intelligence to predict which patients are likely to fall into high-risk trajectories.
Conclusion
The pooled analysis of INTERACT and ATACH-II underscores that SBP management in acute ICH is not a ‘one-size-fits-all’ endeavor. Distinct 24-hour trajectories define the prognosis, with sustained or poorly controlled hypertension significantly increasing the risk of death and disability. These findings advocate for a shift in clinical focus from reaching a solitary SBP threshold to achieving a stable, well-controlled SBP trajectory early in the course of treatment.
Funding and clinicaltrials.gov
The INTERACT and ATACH-II trials were supported by various national health councils and grants, including the National Health and Medical Research Council (NHMRC) of Australia and the National Institutes of Health (NIH).
Trial Registrations: INTERACT1 (NCT00226096), INTERACT2 (NCT00716079), INTERACT3 (NCT03209258), INTERACT4 (NCT03790800), ATACH-2 (NCT01176565).
References
1. Wang X, Phan TG, Ren X, et al. Systolic Blood Pressure Trajectory and Outcomes in Acute Intracerebral Hemorrhage: Pooled Analysis of the 4 INTERACT and ATACH-II Clinical Trials. Neurology. 2026;106(7):e214671.
2. Anderson CS, Heeley E, Huang Y, et al. Rapid blood-pressure lowering in patients with acute intracerebral hemorrhage. N Engl J Med. 2013;368(25):2355-2365.
3. Qureshi AI, Palesch YY, Barsan WG, et al. Intensive Blood-Pressure Lowering in Patients with Acute Cerebral Hemorrhage. N Engl J Med. 2016;375(11):1033-1043.