Association between longitudinal blood pressure and prognosis after treatment of cerebral aneurysm: A nationwide population-based cohort study

Abstract

Background: High blood pressure is a major risk factor for the development and rupture of cerebral aneurysm. Endovascular coil embolization and surgical clipping are established procedures to treat cerebral aneurysm. However, longitudinal data of blood pressure after the treatment of cerebral aneurysm and its impact on long-term prognosis are not well known.

Methods: This retrospective cohort study included 1275 patients who underwent endovascular coil embolization (n = 558) or surgical clipping (n = 717) of cerebral aneurysm in 2002-2015 using the nationwide health screening database of Korea. Systolic and diastolic blood pressure of patients were repeatedly obtained from the nationwide health screening program. We performed a multivariate time-dependent Cox regression analysis of the primary composite outcome of stroke, myocardial infarction, and all-cause death.

Results: During the mean follow-up period of 6.13 ± 3.41 years, 89 patients suffered the primary outcome. Among the total 3546 times of blood pressure measurement, uncontrolled high blood pressure (systolic ≥140 mmHg or diastolic ≥90 mmHg) was 22.9%. There was a significantly increased risk of primary outcome with high systolic (adjusted HR [95% CI] per 10 mmHg, 1.16 [1.01-1.35]) and diastolic (adjusted HR [95% CI] per 10 mmHg, 1.32 [1.06-1.64]) blood pressure.

Conclusions: High blood pressure is prevalent even in patients who received treatment for cerebral aneurysm, which is significantly associated with poor outcome. Strict control of high blood pressure may further improve the prognosis of patients with cerebral aneurysm.

Fig 1. Flow chart of patient inclusion process.

NHIS-HEALS, National Health Insurance Service-National Health Screening Cohort in Korea.

Fig 2. Distribution of blood pressure according to the time from the treatment of cerebral aneurysm.

Proportion of category by (A) systolic blood pressure and (B) diastolic blood pressure among patients who underwent a health examination at each time period since the treatment for cerebral aneurysm. The bar between years 1 and 2 (x-axis) indicates the distribution of blood pressure categories among the patients who underwent a health examination at 1–2 years after treatment for cerebral aneurysm. *Number of blood pressure measurements during the time period. BP, blood pressure (mmHg); DBP, diastolic blood pressure; SBP, systolic blood pressure.

Fig 3. Spline curves of the association between blood pressure and risk of primary outcome.

Hazard ratio and 95% confidence interval for (A) SBP and (B) DBP are presented with solid lines and shaded areas. The data are derived from time-dependent Cox proportional hazard regression model for primary outcome using the method of restricted cubic splines with knots at 110, 120, 130, 140, and 150 mmHg of SBP and at 60, 70, 80, 90, and 100 mmHg of DBP. The reference is SBP 130 mmHg and DBP 80 mmHg. DBP, diastolic blood pressure; SBP, systolic blood pressure.

Fig 4. Effect of blood pressure on primary outcome by subgroup.

Data are HR and 95% CI for (A) SBP and (B) DBP derived from time-dependent Cox proportional hazard regression model for primary outcome. *p-value for interaction between risk factor and blood pressure. CI, confidence interval; DBP, diastolic blood pressure; HR, hazard ratio; SBP, systolic blood pressure.