Author + information
- J. David Spence, MD∗ ()
- ↵∗Stroke Prevention & Atherosclerosis Research Centre, Robarts Research Institute, Western University, 1400 Western Road, London, Ontario N6G 2V4, Canada
In their important paper showing that diastolic hypotension increased the risk of myocardial ischemia, McEvoy et al. (1) nicely explained the mechanism: similar to cerebral perfusion, most of myocardial perfusion occurs during diastole. They found that the risk was largely driven by a wide pulse pressure (>60 mm Hg), meaning that the persons at risk had stiff arteries. This supports the hypothesis (2,3) that the J curve may be due to diastolic pressures that are actually much lower than measured by a cuff.
In 1978, colleagues and I reported (4) that among patients >60 years of age with diastolic pressures >100 mm Hg but no end-organ disease, one-half had a cuff diastolic pressure that was 30 mm Hg higher than the intra-arterial pressure. At the time I called this “pseudohypertension” because I was focusing on the cutoff of 90 mm Hg then used to define the need for antihypertensive therapy. A better name would be cuff artifact. We found that mean arterial pressure calculated from cuff pressures more closely approximated intra-arterial pressures (5). I have estimated that this problem occurs in ∼4% of patients attending hypertension clinics, but it is likely that lesser degrees of cuff artifact are much more common.
In patients with stiff arteries, bradycardia widens pulse pressure because a larger stroke volume is being pushed into a stiff aorta. Thus beta-blockers or diltiazem may aggravate the problem of unrecognized diastolic hypotension. In elderly patients who complain of hypotensive symptoms, but whose cuff pressures do not seem to be hypotensive, it is important to measure intra-arterial pressure. The findings of McEvoy et al. (1) serve as a reminder to consider that the blood pressure measured by a cuff may actually be much higher than the true blood pressure.
Please note: Dr. Spence has reported that he has no relationships relevant to the contents of this paper to disclose.
- 2017 American College of Cardiology Foundation
- McEvoy J.W.,
- Chen Y.,
- Rawlings A.,
- et al.
- Spence J.D.,
- Rayner B.L.
- Spence J.D.
- Spence J.D.,
- Sibbald W.J.,
- Cape R.D.