Raynaud's phenomenon is an abnormal vasospasm of digital arteries, precapillary
arterioles, and dermal arteriovenous shunts that occurs in response to cold and various other stimuli.
As the vasoconstriction takes place with the decreases in vasodilatation, wall to lumen ratio of precapillary
arterioles increases (41).
Delayed SBP recovery is attributed to autonomic dysfunction, high precapillary
resistance at full dilation associated with an increase in wall/lumen ratio (16), and low arterial compliance in individuals with vascular smooth muscle hypertrophy and subclinical arteriosclerosis (35).
She and her associates prospectively analyzed data from 121 patients referred to the Medical University of Vienna between April 2007 and October 2008 for clinical and transthoracic echocardiographic suspicion of precapillary
PH (systolic pulmonary artery pressure of 36 mm Hg or greater).
Apart from sample size considerations, this may be partially explained by the complexity of the pathophysiological mechanisms of microcirculatory alterations such as vasoplegia, shunting, precapillary
dysfunction and endothelial dysfunction (7-12).
Pulmonary arterial or precapillary
pulmonary hypertension is caused by increased pulmonary resistance.
The microvascular damage occurs as a result of poor glycemic control causing precapillary
This refractile material accumulates as particles (often greater than 10 [micro]m in size) accompanied by, or within, giant cells in the perivascular sheath of small precapillary
Langleben D, Dupuis J, Langleben I, et al: Etiology-specific endothelin-1 clearance in human precapillary
The hypoxemia in HPS patients has several causes: diffuse shunts caused by precapillary
and capillary intrapulmonary vascular dilatations, impaired hypoxic vasoconstriction, impaired matching of ventilation to perfusion, pleural effusions, and diaphragmatic dysfunction.
Another approach for simultaneous separation of cations and anions is the formation of the anionic complex between the auxiliary ligand and the analyte metal ions by precapillary
or on-capillary complexation.
The capillary hydrostatic pressure is regulated by the smooth muscle tone in the precapillary
arterioles and the postcapillary venules.