MASKED HYPERTENSIVES AS ASSESSED WITH LASER SPECKLE CONTRAST IMAGING EXHIBIT IMPAIRED SKIN MICROVASCULAR REACTIVITY SIMILAR TO ESSENTIAL HYPERTENSIVE INDIVIDUALS

Abstract

Objective: Laser Speckle Contrast Imaging (LSCI) is a novel method to dynamically assess skin microcirculation with very high resolution and reproducibility compared to other laser methods. Skin microcirculation has been proposed as a model of generalized microvascular function and a potential biomarker in cardiovascular prognosis. Masked hypertension is considered a hypertension phenotype of substantial cardiovascular risk similar to essential hypertension (EH). In this study we evaluated skin microvascular reactivity in masked hypertensives as compared to hypertensives and healthy, normotensive individuals using LSCI coupled with post-occlusive reactive hyperemia (PORH) test. Design and method: We included 20 newly diagnosed masked hypertensives aged 50.0 ± 9.0 and compared them to 70 never treated, newly diagnosed patients with EH aged 49.5 ± 8.7 and 40 healthy, normotensive individuals aged 48.5 ± 8.5 years. Hypertension phenotypes were defined according to standard office and ambulatory blood pressure monitoring (ABPM) criteria. The Mobil-O-Graph-NG (IEM, Stolberg, Germany) device was used for ABPM. All subjects underwent forearm skin perfusion recording under standardized conditions using a LSCI device (PeriCam PSI NR System, Perimed, Järfälla, Sweden) coupled with PORH. Data were analyzed by manufacturer's software (PIMSoft, Perimed). Results were expressed as i) the percentage increase of perfusion from baseline to peak condition (%), and ii) the amplitude of PORH response expressed as the peak cutaneous vascular conductance (CVC) minus baseline CVC. The CVC was calculated as the flux of each time interval divided by mean arterial pressure (perfusion units [PU]/mmHg). Results: Masked hypertensives showed significantly lower percentage increase of perfusion from baseline to peak condition as compared to controls (155.4 ± 48.11 vs 190.54 ± 45.88, p = 0.013) but not compared to hypertensives (155.4 ± 48.11 vs 150.6 ± 41.93, p = NS), respectively. In addition, PORH amplitude was significantly lower in masked hypertensives as compared to controls (0.62 ± 0.2 vs 0.76 ± 0.2, p = 0.02) but no difference was found compared to hypertensives (0.62 ± 0.2 vs 0.52 ± 0.1, p = NS), respectively. Conclusions: Masked hypertensives, when assessed with LSCI coupled with PORH, present impaired skin microvascular reactivity as compared to healthy controls. However, their skin microvascular responses were similar to those of hypertensives, highlighting a state of increased microvascular damage in this hypertension phenotype.