16 Clinical Trials for Various Conditions
Major microvascular blood flow alterations have been documented in patients with severe sepsis. It was also demonstrated that the microcirculation improved in survivors of septic shock but failed to do so in patients dying from acute circulatory failure or with multiple organ failure after shock resolution. Early, effective fluid resuscitation is a key component in the management of patients with severe sepsis and septic shock with the goal of improving tissue perfusion. The best fluid in this early resuscitation phase has been and still is under debate. The aim of this study is to evaluate the effect of Three different Fluids(Albumin 5%, Normal Saline, HES 130 kD) on microcirculation in severe sepsis/septic shock patients using Sidestream Dark Field (SDF) Microscopy and Near-Infrared Spectroscopy (NIRS) analysis.
The scientific aims of the study are to determine how peripheral microcirculatory responsiveness is altered in obese women with Polycystic Ovary Syndrome (PCOS) during local heating and to determine the mechanism for testosterone effects on peripheral microcirculatory responsiveness in women with PCOS.
Surges in the sympathetic nervous system occur at the ictus of a variety of neurological critical illnesses including intracranial hemorrhage and ischemic stroke. It is hypothesized that these exaggerated increases in sympathetic nervous activity produce maladaptations that promote secondary brain injury. One of these possible mechanisms include diffuse vasospasm that cause cerebral ischemia. Hence, methods to abrogate the sympathetic nervous system in this context are under active investigation. One possible method is the regional anesthesia technique of the stellate ganglion nerve block, which is ordinarily used for complex regional pain syndrome, but has been shown to reduce cerebral sympathetic activity and reduces vasospasm in patients with subarachnoid hemorrhage. However, its effect on the microcirculation is not clear. Hence, we propose to study patients receiving the stellate ganglion nerve block as part of their standard medical care and to image their retinal microcirculation before and after the procedure using Optical Coherence Tomography Angiography (OCTA).
This is an open-label, single center, trial that will enroll up to 25 participants with circulatory shock after cardiac surgery. Participants will be administered a topical sublingual nitroglycerin solution and assessed for changes microcirculatory blood flow using incident dark field microscopy.
The investigators hypothesize that the orbital atherectomy system (OAS), a newer generation atherectomy device, reduces the incidence of microcirculatory compromise as compared to older generation rotational atherectomy (RA) due to differences in the mechanism of athero-ablation.
This study is being done to determine if Ranolazine treatment improves coronary microcirculation function among patients with coronary microcirculation dysfunction. We are also looking to learn if symptomatic improvement of chest pain during treatment with Ranalozine is related to improved coronary microcirculation function.
This study will examine the differences in microcirculatory function and mitochondrial respiration in patients with shock after cardiovascular surgery.
Increased dairy intake is associated with improved measures of blood vessel health. Dairy cheese, however, is often high in sodium. Dietary sodium can impair blood vessel function. The researchers examine if and how natural cheese may protect against impairments in blood vessel function caused by sodium. For this study, participants complete four 8-day controlled feeding periods in which they eat cheese (6 oz/day) or no cheese during a low-sodium or high-sodium base-diet. The participants complete baseline experiments while on their normal personal diet and then repeat experiments at the end of each controlled feeding period. In some of our experiments, the researchers use a technique called "microdialysis" (MD). With MD, the researchers perfuse some research drugs into the skin on the forearm through tiny tubing that mimics capillaries. These MD drugs mimic or block substances the body naturally makes to control the small blood vessels in the skin. The drugs remain in nickel-sized areas around the tubing and do not go into the rest of the body. The researchers also use a standard technique called "flow mediated dilation" (FMD) that uses blood pressure cuffs and ultrasound to look at the health of larger blood vessels in the body. FMD includes placing a small tablet of nitroglycerin under the tongue during part of the test.
High blood pressure can cause physical changes to the blood vessels of the body (remodeling). If a person who has high blood pressure also has a lot of blood vessel remodeling with their condition, they are more likely to have poor results with medical treatment for hypertension. The researchers examine the impact of different classes of drugs that doctors use to treat high blood pressure (hypertension) on blood vessel remodeling. Some drugs that doctors prescribe for their patients contain a "sulfhydryl group" (a sulfur atom bonded to a hydrogen atom). Drugs that have the sulfhydryl group may reduce blood vessel remodeling more that drugs that do not. For this study, participants who have high blood pressure perform the experiments, take a drug for 16-weeks to lower blood pressure, and repeat the experiments. The researchers randomly assign one of three drugs to participants who have high blood pressure: a diuretic ("water pill"), a drug containing a sulfhydryl (SH) group, or a drug that does not contain a sulfhydryl group. Participants who do not have high blood pressure perform the experiments, but do not take any of the drugs. In some of our experiments, the researchers use a technique called "microdialysis" (MD). With MD, the researchers perfuse some research drugs into the skin on the forearm through tiny tubing that mimics capillaries. These MD drugs mimic or block substances the body naturally makes to control the small blood vessels in the skin. The drugs remain in nickel-sized areas around the tubing and do not go into the rest of the body. The researchers also analyze very small skin samples (skin biopsy) obtained from the forearm. Lastly, the researchers use a standard technique called "flow mediated dilation" (FMD) that uses blood pressure cuffs and ultrasound to look at the health of larger blood vessels in the body. FMD includes placing a small tablet of nitroglycerin under the tongue during part of the test.
Microcirculatory alterations occur in critically ill patients and those undergoing major surgeries. The severity of perioperative microvascular alterations appear to be related to the severity of organ dysfunction after surgery. Non-cardiac thoracic surgeries comprise a subgroup of high risk surgical procedures which have the potential to significantly affect and impair microcirculatory function but this patient population has not been well studied. Esophagectomy surgery in particular produces a profound systemic inflammatory response which correlates with a number of adverse outcomes. It is likely, though unproven, that microcirculatory derangements may underly these phenomena. Though the study of microcirculatory dysfunction in thoracic surgery is in its infancy, the body of available evidence at this point supports the following hypotheses; that microcirculatory derangements and dysfunction 1) occur during major surgeries including transthoracic esophagectomy 2) may be related to SIRS, 3) may predict adverse outcomes, and 4) may be amenable to modification via specific therapies. We propose a prospective observational study to determine the effects of transthoracic esophagectomy on microcirculatory function. Two hundred patients meeting inclusion criteria undergoing planned transthoracic esophagectomy via thoracotomy incision will be prospectively enrolled at The University of Virginia. Patients will be followed for 28 days or until discharge from the ICU. Evaluation of the sublingual, gastric serosal and mucosal tissues will be performed using sidestream dark field (SDF) imaging using the CytoCam® by Braedius Medical BV (Huizen, The Netherlands). Scoring of the microcirculation will include an index of vascular density (perfused vessel density), an assessment of capillary perfusion (proportion of perfused vessels and microcirculatory flow index) and a heterogeneity index. Note: the CytoCam® will only take a series of images as consistent with a microscope of exposed tissue. Also, the FDA Office of Device Evaluations (ODE) General Surgery Devices Branch One - Light Based/laser (GSDB1) has deemed this device to be exempt from 510(K) approval. http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfPCD/classification.cfm?ID=5021 Data from patient's medical charts before and after surgery (30 days post) will be used for elucidation of specific complications. We will use the cardiovascular and respiratory components of the SOFA score as independent measures of organ dysfunction. Acute kidney injury will be defined by the AKIN criteria as an increase of at least 50% above baseline serum creatinine and will be graded from stage 1 to 3.
This study will determine if administration of sodium nitrite is safe and can improve small vessel blood flow and tissue oxygenation when given as an additional treatment in patients with acute vaso-occlusive crisis (pain crisis) associated with sickle cell disease.
The overall hypotheses of this project is that severe sepsis is associated with endothelial dysfunction; that endothelial dysfunction, in turn, is predictive of subsequent organ failure and death; and that protocolized resuscitation attenuates endothelial cell (EC) dysfunction and improves patient survival.
The purposes of this pilot project are to (a) determine changes in calf muscle blood flow and energy supply resulting from calf muscle exercise, and (b) to determine changes in these variables resulting from exercise training (walking and calf muscle exercise). This is a pilot study to prepare for a larger project in the future. Exercise and exercise training should increase blood flow and energy supply to the calf muscles.
Nitric oxide (NO) is a soluble gas, continuously synthesized by the endothelium, that contributes importantly to vasodilator tone of the coronary and systemic circulations by activating guanylyl cyclase in vascular smooth muscle, causing relaxation. Although regional synthesis of NO by the endothelium contributes to local vasodilator tone, Stamler and co-workers have proposed that regional vascular tone may also be regulated by NO transported from the lungs by hemoglobin as a consequence of enhanced binding of NO to reactive thiols of oxygenated hemoglobin. This study is designed to determine the contribution of hemoglobin-transported NO to forearm microvascular dilator tone in healthy subjects at rest and during regional hypoxia associated with forearm exercise stress, with measurements made before and after regional blockade of endothelial NO synthesis. Findings in this study may be relevant to understanding the physiological contribution and therapeutic potential of hemoglobin-transported NO in the regulation of vasodilator tone in diseases and conditions associated with regional endothelial dysfunction and reduced endothelial NO bioactivity (e.g., hypertension, diabetes mellitus, hypercholesterolemia, cigarette smoking, and estrogen deficiency).
Coronary microcirculatory dysfunction has been known to be prevalent even after successful revascularization of ST-segment elevation myocardial infarction (STEMI) patients. Microvascular obstruction (MVO) in cardiac magnetic resonance (CMR) is significant prognostic indicator in STEMI patients after primary percutaneous coronary intervention (PCI). Although current gold-standard method to assess microvascular damage or dysfunction in STEMI patients is CMR and assessment of MVO, previous study presented that index of microcirculatory resistance (IMR) in culprit vessel of STEMI patients showed significant association with the presence of MVO in CMR and the risk of cardiac death or heart failure admission. Nevertheless, the need for pressure-temperature sensor wire and hyperemic agents significantly limits adoption of IMR in daily practice. Recent technical development enabled angiographic derivation of IMR without pressure wire, hyperemic agents, or thermodilution method. In this regard, the current study will evaluate the feasibility of functional angiography-derived IMR (angio-IMR) in the evaluation of MVO after successful primary PCI for STEMI.
Severe skin damage caused by chronic venous disorders (CVDs) results in relentless pain and poor quality of life for millions of adults in the U.S. each year. DVDs are under-recognized and under-treated disorders shat harm the veins of the legs and at worst, cause skin inflammation and venous leg ulcers. A new way to ease the pain and inflammation is proposed in this study of cryotherapy (cool gel wraps) applied to damaged skin of the lower legs of CVD-affected individuals. The study hypothesis predicts that this novel cryotherapy model and method will significantly improve the health and quality of life for those with CVDs and that the intervention will become a standard of care for CVDs. In addition, the method will, over time, reduce health care costs associated with treating poor CVD outcomes.