Resting and maximal forearm skin blood flows are reduced in hypertension.

Abstract

To find whether the vasodilator capacity of nonacral skin is reduced in hypertension, we measured forearm blood flow by venous occlusion plethysmography in 10 seated norcnotensive (mean±SD mean arterial pressure, 94±5 mm Hg) and 10 hypertensive (112±9 mm Hg) men at rest for 39 minutes while the forearm was heated with water at 42°C, a maneuver known to selectively and maximally vasodilate skin. Blood pressure, measured every 5 minutes, did not change with heating. We found that in the nonnotensive group resting forearm blood flow was higher (3.64±1.12 versus 2.48±0.58 ml/100 ml tissue per minute, p<0.001; nonnotensive group versus hypertensive group) and resting forearm vascular resistance lower (30.17±10.99 versus 48.88±17.37 mm Hg • min • 100 ml tissue per minute, p<0.05; nonnotensive group versus hypertensive group), and maximal forearm Mood flow with local heating was higher (29J2±11.99 versus 18.19±4.50 ml/100 ml tissue per minute,p<0.018; nonnotensive group versus hypertensive group) and vascular resistance lower (4.07±1.04 versus 6.54±1.17 mm Hg • min • 100 ml tissue per minute,p<0.005; nonnotensive group versus hypertensive group). To find whether this degree and duration of local wanning maximally vasodilated the skin in hypertensive subjects (as it does in nonnotensive subjects), we measured forearm skin blood flow before and during local heating plus 10 minutes of ischemia using a laser Doppler flowmeter. Although six of 10 hypertensive subjects displayed a further increase in forearm skin blood flow when ischemia was added to local heating (mean, 65.3%; range, 53.5-81%), overall this was not a significant increase over that seen with heating alone (p>0_JO). We conclude 1) the elevated minimal vascular resistance seen in some regional circulations in hypertensive subjects is also seen in nonacral skin, probably reflecting structural changes in skin blood vessels in hypertension; 2) skin is a useful site to study vascular changes in hypertension; and 3) these changes could contribute to impaired thermoregulatory mechanisms in hypertension. 2 -4 Several hemodynamic studies in humans have tried to differentiate tonically increased vascular smooth muscle activity from structural changes in the vasculature and thereby categorize the basis for the increased peripheral resistance seen in many hypertensive individuals.2 -4 Structural changes have frequently been indexed by increases in minimum vascular resistance, although such increases could be due to either decreased lumen size secondary to an increase in medial thickness or a reduction in the number of vessels (rarefaction).

Impairment of skin blood flow during post-occlusive reactive hyperhemy assessed by laser Doppler flowmetry correlates with renal resistive index

“…This was indicative of a reduced functional response of the cutaneous microcirculation after ischaemia in the hypertensive patients. In contrary to Carberry et al, 7 our results did not show a reduction in maximum laser Doppler flow during cutaneous heating in the hypertensives compared with the controls (160 vs 175, P ¼ NS). This discordance can be accounted for by methodological differences.…”

“…This technique has evidenced deteriorations during ageing, diabetes and hypertension. [6][7][8][9][10][11][12] However, this technique will only be of value if the cutaneous microcirculation can be used as a mirror of the vital territories (cerebral, renal and coronary), which are more difficult to access. Indeed, Holowatz et al 13 recently urged for study of the relations between the pathological modifications of these different microcirculations.…”

Thermoregulation in hypertensive men exercising in the heat with water ingestion

“…Kenney and co-workers (5,8) found that skin temperature was similar between hypertensive and normotensive individuals and that the increases in forearm blood flow were reduced in hypertensive individuals during periods of rising internal temperature induced by dynamic exercise. Carberry and co-workers (21) observed that hypertension reduces the maximal cutaneous vasodilation induced by local warming of the forearm skin. Nevertheless, the cited studies did not separate forearm muscle blood flow from cutaneous blood flow and Kellogg Jr. and co-workers (7) found that cutaneous vascular conductance was probably greater in hypertensive than in normotensive subjects during passive heat stress.…”

Exploring the oxygen challenge test as a microcirculation evaluation model

“…[3][4][5] Tem sido ainda utilizada como um modelo de investigação em vários estados patológi-cos como a diabetes do tipo II, [6] a doença vascular periférica [1] e a hipertensão [7] . No contexto clínico as variáveis microcirculatórias são utilizadas como ferramentas de prognóstico para avaliar a isquémia grave dos membros [8] , a evolução da ferida cutânea [9] e, até para determinar o nível de amputação.…”

“…[3][4][5] It has been used as a research model in various diseases such as type II diabetes [6] peripheral vascular disease [1] and hypertension. [7] Clinically, microcirculatory variables are also used as prognostic tools to assess severe limb ischemia, [8] wound outcome [9] and also to eventually determine the amputation level. [10] Laser Doppler Flowmetry (LDF), Transcutaneous Gasimetry and Evaporimetry are extensively used technologies that enable sensitive, continuous, non-invasive and real-time assessment of circulation related variables.…”