Visit-to-visit blood pressure variability (BPV) among patients at high cardiac risk is independently linked with an increased risk of major cardiovascular events (MCEs), researchers report.
Analysis of data from the SPRINT and ACCORD trials showed that the association between BPV and MCE outcomes was independent of mean blood pressure (BP), and consistent across both studies.
Both extremely low and high BPV were associated with increased risk, the study found.
The findings also indicated that residual risk remained elevated despite antihypertensive therapy in an intensive BP-lowering group, “suggesting that factors beyond mean BP may contribute to adverse outcomes,” according to the paper, published in the European Heart Journal [link here].
“Our findings highlight that BPV should be considered as an independent risk marker, alongside mean BP, underscoring the potential relevance of long-term BP stability for cardiovascular risk assessment,” said the authors, including Professor Hugh Markus, professor of stroke medicine at Cambridge University.
“This association was independent of mean BP and comparable in prognostic value, underscoring the need to determine optimal BPV targets and explore potential BPV-modulating interventions.”
However, the authors also cautioned that the findings are based on a post-hoc analysis and as such cannot establish causality.
The research included 18,415 participants with a median of 12 BP measurements and 3.6-year follow up, of whom 1,244 (6.8%) had experienced MCEs.
Among the cohort, mean baseline BP was 137.8/76.4mmHg, and participants were stratified into tertiles (T1, T2, T3) based on visit-to-visit BP variation (VIM; variation independent of mean).
Greater systolic (SBP) and diastolic (DBP) blood pressure variability, as well as higher mean SBP, were significantly associated with a greater risk of events (all p<0.001), while higher mean DBP was associated with lower risk (HR 0.98).
The highest event rate for SBP-VIM was observed in T3, with an intermediate risk in T1 and the lowest risk in T2 (p<0.0001). A similar pattern was observed for DBP-VIM, with T2 consistently showing the lowest event rate (p<0.0001).
The study found that each 1-unit increase in SBP-VIM was associated with a 3% higher risk of MCEs (HR 1.03; p<0.001). Compared with T1, T2 showed a lower risk (HR 0.82), whereas T3 showed a higher risk (HR 1.15).
BPV and individual event risk
Meanwhile, 3.9% of patients experienced MI during follow-up, with strong associations between SBP-VIM and MI risk (log-rank p=0.0005), and the poorest outcomes occurring in those in the highest tertile.
The researchers found that each one-unit increase in SBP-VIM was associated with a 3% higher risk of MI (HR 1.03; p=0.001) .
In the case of cardiovascular death, 1.97% died from cardiovascular causes during follow-up.
Each one-unit increase in SBP-VIM was associated with a 5% higher risk of cardiovascular death. (HR 1.05; p<0.001).
Stroke occurred in 1.5% of participants, with higher systolic and diastolic BPV significantly associated with increased stroke risk across all variability metrics and the highest tertiles showing the poorest event-free survival.
“When examining individual components of MCEs, BPV was significantly associated with the risks of myocardial infarction and cardiovascular death. No significant association with stroke was observed in this analysis,” the authors said.
Finally, the authors noted that the “prognostic relevance” of BPV appeared to be weaker under intensive blood pressure lowering, indicating that its clinical utility “may be modified by treatment context,” a finding that echoed other post hoc analyses of trials that found associations between BPV and cardiovascular outcomes are more pronounced under standard BP control and less so under intensive strategies.
They posited several possible reasons for this phenomenon, including the influence of antihypertensive drug classes on BPV, mitigating risk through pathways not fully captured by mean SBP alone and the fact that intensive treatment can yield a narrower BP distribution and fewer clinical events.
“This heterogeneity warrants further investigation, as understanding drug-specific influences on BPV may help inform personalised treatment strategies that consider not only BP lowering but also long-term BP stability,” they concluded.