In patients with coronary artery disease, a J-curve relationship has been reported between blood pressure (BP) and future cardiovascular events. However, this is controversial. We investigated the relationship between BP at 1 year after myocardial infarction (MI) and mortality.Design and Method:
We analyzed a multicenter registry and identified 2,889 patients who presented with acute MI and were treated with percutaneous coronary intervention between 2004 and 2009. Patients survived for 1 year after MI and were measured blood pressure at 1 year. The association between BP at 1 year and mortality (all-cause death and cardiac death) within three years after BP measurement was examined. Cox proportional hazards models were fitted to examine the effects on mortality of blood pressure at 1 year and of blood pressure as a time-dependent covariate.Results:
Among the 2,889 patients, 278 (9.6 %) experienced mortality (cardiac death: 94 [3.3%]) at 2.5 years (median) of follow-up after BP measurement at 1 year. The relationship between systolic BP or diastolic BP and mortality did not follow J-curve which were examined by cox proportional hazards using BP at 1 year as a time-dependent covariate. The mortality increased in patients with systolic BP > 150 mmHg or diastolic BP > 90 mmHg (13.8%, n = 319). In multivariate analysis, systolic BP > 150 mmHg or diastolic BP > 90 mmHg at 1 year were one of independent predictors of mortality (Adjusted Hazard Ratio [HR] 1.84, 95% Confidence interval [CI] 1.31–2.60, p = 0.001) and cardiac death (adjusted HR 2.11, 95% CI 1.17–3.81, p = 0.014).Conclusions:
In stable post-MI patients at 1 year, high BP (systolic BP > 150 or diastolic BP > 90 mmHg) were associated wtih increased risk of mortality. Tight blood pressure control may be required to reduce the substantial risk for mortality beyond first year post-MI.