Experts advise caution with the use of blood pressure-lowering treatment in patients with heart disease, based on results of the CLARIFY trial that link strict blood pressure control to increased risk of heart attack, stroke and death.
Presented at the European Society of Cardiology Congress 2016 in Rome and published in The Lancet, this study looked at the association between blood pressure and heart events in patients with heart disease. While there’s no question that high blood pressure increases risk of heart events and death, exactly what the ideal target for blood pressure is—particularly in patients with heart disease—remains highly debated.
To learn more, researchers analyzed data from the CLARIFY registry, which tracks the health of heart disease patients from 45 countries. From November 2009 to June 2010, nearly 22,700 participants enrolled in the study, all of which had heart disease and were treated for high blood pressure. On average, participants were 65 years old upon enrollment, most of which were male.
Overall, there were 2,101 heart events and deaths over the five-year follow-up period. After comparing blood pressure levels prior to these events, researchers found that blood pressure had a significant impact on participants’ cardiovascular risk.
Not surprisingly, a systolic blood pressure greater than 140 mmHg or diastolic blood pressure greater than 80 mmHg was associated with significantly increased risk for heart events and death. Systolic blood pressure is the top number in blood pressure readings, while diastolic is the bottom number. To put it in perspective, “normal” or healthy blood pressure in the general population is anything below 120 mmHg/80 mmHg.
Surprisingly, however, researchers also found that low blood pressure was also associated with increased cardiovascular risk among participants. Participants with a systolic blood pressure below 120 mmHg had 56% greater risk for heart events or death. Similarly, diastolic blood pressure less than 70 mmHg was associated with a 41% increase in risk, and diastolic blood pressure below 60 mmHg doubled risk for heart events and death.
The take-home message, as authors explain, is that any extreme with blood pressure can have negative effects on heart health. There’s no question that high blood pressure increases risk for heart events. In fact, this study confirms that blood pressure greater than 140 mmHg/80 mmHg is associated with increased heart risks in patients with heart disease. However, findings also suggest that lowering blood pressure too much can be dangerous in patients with heart disease, as blood pressure below 120 mmHg/70 mmHg was associated with increased heart risks.
Therefore, authors advise caution when using blood pressure-lowering treatment in patients with heart disease. Medication can help reduce blood pressure levels in patients with hypertension, but doctors should be careful not to lower blood pressure too much in patients with heart disease.
The good news, however, is that this is rarely a problem for most Americans. It’s estimated that one in three U.S. adults has high blood pressure, defined as anything over 140/90 mmHg. Only about half of the population with hypertension is controlled, even with medication. So, as experts explain, the focus on lowering blood pressure in patients with hypertension remains an important goal, as well as identifying which patients may benefit from tighter blood pressure control.