BP below 120/70 mmHg in patients with CAD associated with more CV events

Vidal-Petiot E, Ford I, Greenlaw N, et al.
Lancet 2016; published online ahead of print

Background

The clinical benefit of intensive versus less-intensive blood pressure (BP)-lowering in hypertensive patients at high CV risk is debated. Some studies showed that intensive BP-lowering is associated with decreased CV events [1], while other trials did not show a benefit of BP targets below 140/90 mmHg [2,3]. Moreover, there are data suggesting that the benefit of BP-lowering treatment below a certain limit might even be reversed, a very relevant point, since the heart perfusion is compromised at low diastolic pressure [4,5].
In this study, the relationship between achieved BP and CV outcomes was evaluated in a large cohort of patients with stable CAD treated for hypertension from the CLARIFY registry (patients from 45 countries, enrolled between Nov 26, 2009 and June 30, 2010).

Main results

At baseline, the mean average systolic and diastolic BP of 22 672 adult patients with CAD and hypertension were 133.7 and 78.2 mmHg, respectively. After a median follow-up of 5 years, 9.3% of patients met the primary composite outcome of CV death, MI, or stroke.
Compared with the systolic reference group (SBP: 120–129 mmHg), the adjusted HRs for the primary outcome were:

• HR for SBP=140–149 mmHg: 1.51; 95% CI: 1.32–1.73
• HR for SBP ≥ 150 mmHg: 2.48; 95% CI: 2.14–2.87
• HR for SBP<120 mmHg: 1.56; 95% CI: 1.36–1.81.

Compared with the diastolic reference group (DBP: 70–79 mmHg), the adjusted HRs for the primary outcome were:

• HR for DBP=80–89 mmHg: 1.41; 95% CI: 1.27–1.57 

• HR for DBP ≥ 90 mmHg: 3.72; 95% CI: 3.15–4.38
• HR for DBP 60–69 mmHg: 1.41; 95% CI: 1.24–1.61
• HR for DBP <60 mmHg: 2.01; 95% CI: 1.50–2.70.

Similarly steep J-curves, for both systolic and diastolic blood pressure, were seen for CV death, all-cause death, MI, and hospital admission for HF, but not for stroke.  

Conclusion

In a large observational cohort of patients with hypertension and CAD, SBP< 120 mmHg and DBP<70 mmHg were associated with increased CV outcomes, even after multiple adjustments for baseline CV disease, risk factors, and medicines. These data support the existence of a J-curve phenomenon and suggest that too low blood pressure levels should be avoided in these patients.

Find this article online at The Lancet

References

1. 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: 2103–16.
2. Cushman WC, Evans GW, Byington RP, et al. Effects of intensive blood-pressure control in type 2 diabetes mellitus. N Engl J Med 2010; 362: 1575–85.
3. Benavente OR, Coff ey CS, Conwit R, et al. Blood-pressure targets in patients with recent lacunar stroke: the SPS3 randomised trial. Lancet 2013; 382: 507–15.
4. Cruickshank JM, Thorp JM, Zacharias FJ. Benefits and potential harm of lowering high blood pressure. Lancet 1987; 1: 581–84.
5. Messerli FH, Panjrath GS. The J-curve between blood pressure and coronary artery disease or essential hypertension: exactly how essential? J Am Coll Cardiol 2009; 54: 1827–34.