- Decline in BP- Major (-63 to -20), 547 subjects or Minor (-20 to -10), 1507 subjects
- Stable BP- (-10 to +10), 8981 subjects
- Increase in BP- Major (+65 to +20), 303 subjects or Minor (+20 to +10), 1479 subjects
Data was obtained in regards to ischemic stroke incidence and type for a median of 18.7 years. They report:
- Little change in BP after standing in the entire cohort. SBP increased 0.4 mmHg and DBP increased by 3mmHg.
- Patients with orthostatic SBP and DBP decreases of greater than 20mmHg had an increased incidence of thrombotic and cardioembolic strokes.
- Patients with orthostatic SBP decreases and increases of greater than 20mmHg had an increased incidence of lacunar strokes.
The authors conclude that these findings are consistent with previous studies showing silent strokes in elderly hypertensive patients with orthostatic hypo- or hypertension. They speculate that this BP elevation from sitting to standing could be due to excessive sympathetic nervous system activation, which could in turn lead to endothelial dysfunction. Another theory discussed in the editorial and by these authors is that elderly patients with orthostatic hypertension have been shown have excessive BP dipping at night with greater than a 25mmHg drop in BP (referred to as “extreme dipping“). These “extreme dippers” had an increased risk of silent stroke as well. Several limitations are present. Only a baseline orthostatic value is present. How would these values change over time or would they hold true? Second, not every participant had an MRI to look for silent strokes. However, this study was prospective and contains a large sample size.
How will this change practice? Hard to say. This could merely serve as a marker for autonomic dysfunction and might not be a modifiable risk factor. Simple measures such as compression stockings have been used to control both orthostatic hypo- and hypertension. Beta blockers could be useful in controlling orthostatic hypertension. Further clinical trials to directly examine these relationships could help in answering these questions.