Last Updated: 2008-01-16 17:37:27 -0400 (Reuters Health)
NEW YORK (Reuters Health) – Elevated systolic blood pressure after a high-risk myocardial infarction (MI) is associated with an increased risk of subsequent stroke and cardiovascular events, according to results of a study published in the January issue of Hypertension.
"While hypertension before MI is associated with greater left ventricular (LV) dilation and a higher risk of subsequent heart failure (HF), stroke, and death, a drop in blood pressure after MI is common," write Dr. Scott D. Solomon of Brigham and Women’s Hospital in Boston, Massachusetts, and colleagues. "Thus, the influence of post-MI blood pressure on cardiovascular outcomes may be complex, particularly in patients with large infarctions."
Using data from the Valsartan in Myocardial Infarction Trial, the researchers assessed the relationship between antecedent hypertension and in two of three follow-up visits during the first 6 months and subsequent cardiovascular events over a median follow-up of 24.7 months. Elevated blood pressure was defined as systolic blood pressure greater than 140 mm Hg, and low blood pressure was defined as systolic blood pressure less than 100 mm Hg.
Of 14,703 patients, 8575 (58.3%) reported antecedent hypertension at the time of enrollment, and 7609 (88.7%) of these were receiving medical treatment for hypertension. Compared to patients without antecedent hypertension, those with antecedent hypertension had higher average systolic blood pressures across the follow-up visits at 1, 3, and 6 months (difference in medians, 9 mm Hg; p < 0.0001).
An association was observed between antecedent hypertension and a significantly increased risk of stroke (hazard ratio 1.27), HF hospitalization (HR 1.19), cardiovascular death (HR 1.11), and a composite of death, MI, heart failure, stroke, or cardiac arrest (HR 1.13).
Overall, 10,532 patients had not experienced a cardiovascular event by the 6-month follow-up. Of these, 1522 (14.5%) had elevated systolic blood pressure, and 602 (5.7%) had low blood pressure 1 to 6 months post-MI. While reduced blood pressure after MI was associated with an increased risk of adverse events, elevated blood pressure was associated with a significantly increased risk of stroke (adjusted HR 1.64) and combined cardiovascular events (adjusted HR 1.14).
"Whether more aggressive treatment of elevated blood pressure in patients with a previous MI can reduce adverse outcomes remains unknown," Dr. Solomon’s team writes.
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