Characterization of Microvascular Post Occlusive Hyperemia Using Laser Doppler Flowmetry Technique in Subjects With Cardiometabolic Disorders.

INTRODUCTION: Laser Doppler flowmetry (LDF) provides a noninvasive real-time quantification of relative changes in cutaneous perfusion. Assessment of the microvascular function can provide information on the development of various cardiometabolic disorders. In recent years, non-invasive measurements have gain attention, due to the potential complications associated to invasive procedures. OBJECTIVE: To differentiate the microvascular function between subjects with cardiometabolic disorders and healthy controls. METHODS: Evaluation through LDF during post-occlusive reactive hyperemia (PORH) in patients with or without history of cardiometabolic disorders. RESULTS: Peak values of microvascular flow during post-occlusive reactive hyperemia and both upload and recovery slopes were lesser in the pathological group. CONCLUSION: A novel approach to characterize LDF during PORH was useful to differentiate patients with cardiometabolic disorders from healthy subjects.

Modeling Cardiac Hemodynamic Response During Exercise in Health and Hypertrophic Cardiomyopathy.

INTRODUCTION: Hypertrophic cardiomyopathy (HCM) is associated with altered hemodynamics in the left ventricular outflow tract and tissue abnormalities. Exercise testing has become an integral and powerful tool for the noninvasive evaluation of HCM and, in some patients, it could define a treatment strategy. Obiective: To model the hemodynamic alterations during exercise in healthy and HCM patients, obtained by noninvasive methods. METHODS: Cardiac output (CO), heart rate (HR), arterial blood pressure (ABP) and Total Peripheral Resistance (TPR) were assessed during exercise. The evaluation included a curve-fitting approach (sigmoidal model) that allowed a quantitative comparison of CO profiles. RESULTS: When compared to controls, patients with HCM showed reduced peak exercise cardiac output and demonstrated high peripheral resistance during exercise. Analysis of modeled it CO curves revealed a higher maximum rate of recovery in healthy individuals than in HCM patients. CONCLUSION: The application of the sigmoidal model showed to be efficient in the characterization of CO dynamics for the different studied groups.

Flow Mediated Dilation in Cirrhosis: A Pilot Study in Different Stages of the Disease.

INTRODUCTION: Cirrhosis is associated with changes in the cardiovascular system, where the circulatory dysfunction is compensated by the development of a hyperdynamic circulation. Endothelial function can be understood as the endothelium capability to release Nitric Oxide (NO) where an impairment in the normal development of this process constitutes a main step in the genesis and progression of atherosclerosis, a major cause of cardiovascular events. In recent years, non-invasive measurements have gained attention, due to the potential complications associated to invasive procedures. OBJECTIVE: To evaluate endothelial function (EF) in patients with cirrhosis, in different stages of the disease, complemented with hemodynamic measurements. METHODS: Individuals were divided in three age groups, according to the severity of their disease. EF was assessed by using the flow mediated dilation technique (FMD), jointly with noninvasive determination of cardiac output (CO), total peripheral resistance (TPR) and arterial compliance (AC). RESULTS: TPR showed a decrease in advanced severity while AC had an increase. Particularly, EF was found to be higher in CHC group, decreasing in CHB and more pronounceably in CHA. Concomitantly, an inverse behavior was observed regarding CO evolution. CONCLUSION: EF was noninvasively evaluated in cirrhosis, in terms of the progression of the disease. Hyperdynamic states in the more advanced condition were accompanied by a higher vascular reactivity, probably associated with higher peripheral NO release and increased AC.

Modeling young and adult patients with cirrhosis through a three element windkessel (WK3e).

INTRODUCTION: Measurement of hemodynamic parameters constitutes an important tool in the management of patients with cirrhosis. In recent years, non-invasive measurements have gain attention, due to the potential complications associated to invasive procedures. OBJECTIVE: To characterize the hemodynamic alterations of cirrhosis in young and adult subjects, through a three element windkessel (WK3e). METHODS: Individuals were divided in three age groups: Young Healthy group (control, CG), Young Cirrhotic Group (YCG) and Adult Cirrhotic Group (ACG). A Finapres® Nova device was used to obtain cardiac output (CO), heart rate and arterial blood pressure. Systemic arterial compliance (C), peripheral resistance (R) and characteristic impedance (Zc) were also provided. Effective arterial elastance (Ea), left ventricular work (LVW), input impedance, efficiency and model cutoff frequency (WKCF) were assessed based on the provided data. RESULTS: CO resulted to be higher in ACG than in CG and YGC. LVW, C and WKcf showed an increase, while R and Ea showed a decrease. However, this behavior was not observed in YCG. CONCLUSION: Cirrhosis was properly modeled in young and adult subjects in terms of non-invasive measurements and a WK3e.

Arterial pressure beat to beat characterization during post-occlusive reactive hyperemia.

INTRODUCTION: In recent years, peripheral arterial tonometry (PAT, a non-invasive and reproducible technique) has gained considerable interest. In this sense, arterial capacity to react to vasoactive stimulus (induced by reactive hyperemia) is known as vascular reactivity (VR). OBJECTIVE: Post ischemic beat to beat VR characterization was performed based on PAT measurements. METHODS: Systolic Blood Pressure (SBP) and Augmentation index (AIx) variations were modeled, as a response to flow stimulus. RESULTS: Obtained R2 values were around 70% for VR while, to a lesser degree, AIx fit was about 50% Conclusion: Beat to Beat VR was described in terms of SBP and AIx behavior. Further studies are needed to determine the clinical usefulness of the proposed indicators.