Low Systolic Blood Pressure Target May Increase Cardiovascular Risks

Targeting systolic blood pressure (SBP) to a goal <120 mm Hg may increase the risk of death and hospital admission for heart failure, but not the risk for outcomes such as myocardial infarction (MI) and stroke, according to results from a secondary analysis of 2 clinical trials published in The Lancet.¹

The Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial (ONTARGET) and the Telmisartan Randomised Assessment Study in ACE Intolerant Participants With Cardiovascular Disease (TRANSCEND; both trials registered with ClinicalTrials.gov identifier: NCT00153101).

Reaching a blood pressure goal <140/90 mm Hg, as recommended by current guidelines, may reduce the overall risk of cardiovascular events. However, low SBP increases the risk for some individual cardiovascular events, such as coronary disease events in hypertensive populations.¹

The Systolic Blood Pressure Intervention Trial (SPRINT) trial demonstrated that low SBP affects the risk for individual cardiovascular outcomes in different ways. For example, intensive treatment of SBP <120 mm Hg lowered the risk of composite cardiovascular events, which was driven by reductions in heart failure and all-cause mortality. The risk of stroke and MI, however, remained largely unaffected.²

ONTARGET and TRANSCEND were randomized controlled trials that evaluated the effect of telmisartan on composite cardiovascular outcomes — MI, stroke, hospitalization for heart failure, and cardiovascular death — in patients with or at high risk for cardiovascular disease.

ONTARGET compared telmisartan vs ramipril or both drugs combined, while TRANSCEND included patients intolerant of angiotensin-converting-enzyme (ACE) inhibitors and compared telmisartan vs placebo. Although telmisartan and combination treatments lowered blood pressure to a greater extent than ramipril or placebo, there were no differences in composite cardiovascular outcomes across all groups.^3,4

In a secondary analysis of ONTARGET and TRANSCEND, Michael Böhm, MD, from the University Hospital of the Saarland in Homborg, Germany, and colleagues evaluated the relationship between SBP and diastolic blood pressure (DBP) and the composite cardiovascular outcome and individual components of the composite outcome.¹

The secondary analysis included 25,127 patients from ONTARGET and 5810 patients from TRANSCEND. Compared with patients with treated SBP of 120 to 140 mm Hg (n=16,099), patients with treated SBP of <120 mm Hg (n=4052) were at higher risk for the composite cardiovascular outcome (adjusted hazard ratio [HR], 1.14; 95% CI, 1.03-1.26) cardiovascular death (adjusted HR, 1.29; 95% CI, 1.12-1.49), and all deaths (adjusted HR, 1.28; 95% CI, 1.15-1.42).¹

The risk of MI, hospitalization for heart failure, and stroke were similar in both SBP target groups.¹

On-treatment DBP of <70 mm Hg was associated with a higher risk of the composite cardiovascular outcome, hospital admission for heart failure, MI, and all-cause death, compared with on-treatment of DBP 70 to 80 mm Hg.¹

“Blood pressure goals are difficult to define,” Dr Böhm told Cardiology Advisor. “Guidelines usually define only the upper limit of the blood pressure control. This study determines that below a blood pressure of 120 mm Hg and, in particular, 110 mm Hg, there is an increase of risk for many end points. Current guidelines will have to use the upper and the lower boundaries of blood pressures to define optimal blood pressure control.”

This subanalysis, ONTARGET, and TRANSCEND were funded by Boehringer Ingelheim. Dr Böhm was a member of the steering committees of ONTARGET and TRANSCEND.

Reference

1. Böhm M, Schumacher H, Teo KK, et al. Achieved blood pressure and cardiovascular outcomes in high-risk patients: results from ONTARGET and TRANSCEND trials [published online April 5, 2017]. Lancet. doi:10.1016/S0140-6736(17)30754-7
2. SPRINT Research Group; Wright JT Jr, Williamson JD, Whelton PK, et al. A randomized trial of intensive versus standard blood-pressure control. N Engl J Med. 2015;373(22):2103-2116. doi:10.1056/NEJMoa1511939
3. ONTARGET Investigators; Yusuf S, Teo KK, Pogue J, et al. Telmisartan, ramipril, or both in patients at high risk for vascular events. N Engl J Med. 2008;358(15):1547-1559. doi:10.1056/NEJMoa0801317
4. Telmisartan Randomised AssessmeNt Study in ACE iNtolerant subjects with cardiovascular Disease (TRANSCEND) Investigators; Yusuf S, Teo K, Anderson C, et al. Effects of the angiotensin-receptor blocker telmisartan on cardiovascular events in high-risk patients intolerant to angiotensin-converting enzyme inhibitors: a randomised controlled trial. Lancet. 2008;372(9644):1174-1183. doi:10.1016/S0140-6736(08)61242-8