Blood Pressure at 6 Months After Acute Myocardial Infarction and Outcomes at 2 Years: The Perils Associated With Excessively Low Blood Pressures.

BACKGROUND

This study aimed to determine the association between achieved blood pressure at 6-month follow-up and cardiovascular outcomes at 2 years in patients treated with β-blockers and renin-angiotensin-aldosterone blockers after acute myocardial infarction (AMI).

METHODS

We analyzed data from 5503 patients enrolled in the national AMI registry. Patients with myocardial reinfarction (MrI), rehospitalization for heart failure (rHHF), or stroke before 6-month follow-up were excluded. Achieved blood pressures were categorized into 10-mm Hg increments. The primary outcome was all-cause death. The secondary outcome was a composite of all-cause death, MrI, and rHHF. Hazard ratios (HRs) were estimated with multivariable-adjusted Cox hazards models using 125- to 134-mm Hg systolic blood pressure (SBP) and 75- to 84-mm Hg diastolic blood pressure (DBP) subgroups as reference.

RESULTS

After a median follow-up of 2.1 years, SBP < 115 mm Hg was associated with increased risks for all-cause death (adjusted HR: 2.202 [1.158-4.188]) and for a composite outcome (HR: 1.682 [1.075-2.630]). Likewise, DBP < 75 mm Hg tended to be associated with an increase in all-cause death (HR: 2.078 [0.998-4.327] for DBP of 65 to 74 mm Hg; HR: 2.610 [1.256-5.423] for DBP < 65 mm Hg). Even in patients <75 years, the risk of a composite outcome was increased for DBP < 65 mm Hg (HR: 2.492 [1.401-4.434]).

CONCLUSIONS

Low blood pressure achieved with β-blocker and renin-angiotensin-aldosterone blocker at 6 months was associated with an increased risk of all-cause mortality independently of confounding factors in patients with AMI. This finding suggests that caution should be taken for patients with AMI who use blood-pressure-lowering treatments.