P77 Near Infrared Spectroscopy (Nirs) Can Detect Differences in Microvascular Reactive Hyperaemia in the Presence of Hypertension


Background: Hypertension has adverse effects on microvascular function but there are limited methods that permit non-invasive assessment of the microcirculation in man in vivo. We used Near Infrared Spectroscopy (NIRS) to assess microvascular reactive hyperaemia in skeletal muscle following a short period of ischemia. We tested if differences between normotensive and hypertensive individuals could be detected. Methods: Older adults enrolled in a population-based cohort study underwent measurements of oxy-Hb changes during a 30-second arterial occlusion and hyperaemic response using NIRS (Portamon, Artinis). Time-to-peak hyperaemic response was calculated. Hypertension diagnosis was determined by questionnaire and clinic blood pressure (BP) (diastolic BP > 90 mmHg or systolic BP > 140 mmHg). Diabetes diagnosis and information about medication were determined by questionnaire. Data are mean (SD) or adjusted mean±SEM. Multivariable linear regression was used. Associations with hypertension were adjusted for age, gender, ethnicity and presence of diabetes. Results: 129 participants (99 = male, 72(6) years old, 74(57%) hypertensive participated). Time-to-peak hyperaemic response was significantly longer in hypertensive than normotensive participants after adjustment for age and gender (12.5±0.49 versus 10.5±0.57seconds, p = 0.06). This association persisted after adjustment for ethnicity and the presence of diabetes (12.6±0.50 versus 10.5±0.57, p = 0.03). Conclusion: Hypertension is associated with impairment of post-ischemic reactive hyperaemia in skeletal muscle microvasculature. Differences between hypertensive and normotensive older adults can be detected non-invasively using NIRS.

Artery Research