Patients with postural tachycardia syndrome had significantly lower percent brachial flow-mediated dilation compared to healthy controls (6.23% vs 10.6%, P=0.014), suggesting endothelial dysfunction.
Case-Control (n=28)
Is endothelial function impaired in patients with postural tachycardia syndrome compared to healthy controls?
Patients with PoTS have significantly reduced flow-mediated dilation compared with healthy controls, indicating endothelial dysfunction in conduit arteries.
Absolute Event Rate: 6.23% vs 10.6%
p-value: p=0.014
The purpose of this study is to evaluate endothelial function in postural tachycardia syndrome (PoTS), a poorly understood chronic condition characterized by a state of consistent orthostatic tachycardia (delta heart rate ≥30 beats per minute) upon standing without orthostatic hypotension. Nineteen patients with PoTS and 9 healthy controls were studied after 3 days of a fixed, caffeine-free, normal sodium (150 milliequivalents/day) diet. All participants underwent autonomic function testing, including sinus arrhythmia, valsalva maneuver, hyperventilation, cold pressor, handgrip, and a standing test with catecholamine measurements, followed by endothelial function testing. We analyzed 3 measures of endothelial function: percent brachial flow-mediated dilation, digital pulsatile arterial tonometry, and postischemic percent leg blood flow. Flow-mediated dilation was significantly lower in patients with PoTS (6.23±3.54% for PoTS) than in healthy controls (10.6±4.37% for controls versus, P =0.014). PoTS and controls had similar digital pulsatile arterial tonometry (1.93±0.40 arbitrary units for controls versus 2.13±0.63 arbitrary units for PoTS). PoTS had similar but suggestive percent leg blood flow to controls (313±158% for PoTS versus 468±236% for controls, P =0.098). Patients with PoTS have significantly reduced flow-mediated dilation compared with healthy controls, suggesting that PoTS is characterized by endothelial dysfunction in conduit arteries. Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT01308099.
Chopoorian et al. (Mon,) conducted a case-control in Postural Tachycardia Syndrome (PoTS) (n=28). Postural Tachycardia Syndrome (exposure) vs. Healthy controls was evaluated on Percent brachial flow-mediated dilation (p=0.014). Patients with postural tachycardia syndrome had significantly lower percent brachial flow-mediated dilation compared to healthy controls (6.23% vs 10.6%, P=0.014), suggesting endothelial dysfunction.