Reduced systemic microvascular density and reactivity in individuals with early onset coronary artery disease.

OBJECTIVE: This study sought to test whether patients with early-onset coronary artery disease (EOCAD, n=30) showed systemic microvascular rarefaction and endothelial dysfunction in comparison to age- and sex-matched healthy controls (CTL, n=30), as evaluated by skin video-capillaroscopy. METHODS: Functional capillary density (FCD) was defined as the number of spontaneously perfused capillaries per square millimeter of skin area and assessed by high-resolution intra-vital color microscopy in the dorsum of the middle phalanx. Capillary recruitment (capillary reserve) was evaluated using post-occlusive reactive hyperemia (PORH) after arm ischemia for 3min. RESULTS: The mean capillary density at rest was significantly reduced in patients with EOCAD compared to controls (CTL 95±20 and EOCAD 80±18capillaries/mm(2), P=0.0040). During PORH, capillary density was also markedly reduced in EOCAD patients (CTL 96±18 and EOCAD 71±20capillaries/mm(2), P<0.0001). Moreover, the capillary density in EOCAD patients was significantly reduced during PORH (EOCAD at rest 80±19 and EOCAD during PORH 71±20capillaries/mm(2), P=0.0073). CONCLUSIONS: Patients with EOCAD presented systemic capillary rarefaction and impaired microvascular endothelial function. Thus, the early detection of these microvascular alterations in young adults at an increased risk of coronary artery disease could be useful as a surrogate marker of subclinical atherosclerosis.

Impairment of systemic microvascular endothelial and smooth muscle function in individuals with early-onset coronary artery disease: studies with laser speckle contrast imaging.

OBJECTIVES: The assessment of systemic microvascular reactivity is currently considered to be critical in the stratification of cardiovascular risk. In the present study, we compared skin microvascular function in individuals with early-onset (premature) coronary artery disease (EOCAD, n=30) with that of age-matched and sex-matched healthy individuals (n=30). MATERIALS AND METHODS: Using laser speckle contrast imaging, cutaneous blood flow was assessed in the forearm at rest and during reactivity tests, including postocclusive reactive hyperemia and the iontophoresis of acetylcholine or sodium nitroprusside with increasing currents of 30, 60, 90, 120, 150, and 180 µA for 10-s intervals spaced 1 min apart. Carotid intima-media thickness was evaluated using an ultrasound system and a 7.5 MHz ultrasound transducer. RESULTS: The endothelium-dependent skin microvascular vasodilator responses that were induced by both acetylcholine and postocclusive reactive hyperemia were significantly reduced in patients with EOCAD compared with healthy individuals. The vasodilator responses that were induced by sodium nitroprusside were also significantly reduced in individuals with EOCAD. These systemic microvascular alterations were concurrent with increased carotid intima-media thickness in these patients. CONCLUSION: Laser speckle contrast imaging identifies endothelial-dependent and endothelial-independent microvascular dysfunction in individuals presenting with EOCAD, and thus could be valuable as an early peripheral marker of atherothrombotic disease.