α-Adrenergic regulation of skeletal muscle blood flow during exercise in patients with heart failure with preserved ejection fraction.

Heart failure with preserved ejection fraction (HFpEF) has been characterized by lower blood flow to exercising limbs and lower peak oxygen utilization ( ), possibly associated with disease-related changes in sympathetic (α-adrenergic) signaling. Thus, in seven patients with HFpEF (70 ± 6 years, 3 female/4 male) and seven controls (CON) (66 ± 3 years, 3 female/4 male), we examined changes (%Δ) in leg blood flow (LBF, Doppler ultrasound) and leg to intra-arterial infusion of phentolamine (PHEN, α-adrenergic antagonist) or phenylephrine (PE, α-adrenergic agonist) at rest and during single-leg knee-extension exercise (0, 5 and 10 W). At rest, the PHEN-induced increase in LBF was not different between groups, but PE-induced reductions in LBF were lower in HFpEF (-16% ± 4% vs.

Near-infrared spectroscopy for kidney oxygen monitoring in a porcine model of hemorrhagic shock, hemodilution, and REBOA.

Acute kidney injury is a common complication of trauma and hemorrhagic shock. In a porcine model of hemorrhagic shock, resuscitative endovascular balloon aortic occlusion (REBOA) and hemodilution, we hypothesized that invasive kidney oxygen concentration measurements would correlate more strongly with noninvasive near infra-red spectroscopy (NIRS) oxygen saturation measurements when cutaneous sensors were placed over the kidney under ultrasound guidance compared to placement over the thigh muscle and subcutaneous tissue. Eight anesthetized swine underwent hemorrhagic shock 4 of which were resuscitated with intravenous fluids prior to the return of shed blood (Hemodilution protocol) and 4 of which underwent REBOA prior to resuscitation and return of shed blood (REBOA protocol).

Quantitative Assessment of Three-Dimensional Aorto-Mitral Angle in Hypertrophic Cardiomyopathy.

Background: This study explored the correlation between the 3-dimensional aorto-mitral angle and pressure gradients in patients with obstructive hypertrophic cardiomyopathy (HCM) undergoing septal myectomy, with or without aortic shortening.

Methods: A single-site, retrospective observational study was conducted at a tertiary-level hospital; 67 patients underwent septal myectomy for obstructive HCM. Preoperative and postoperative transesophageal images were analyzed offline to measure the end-systolic 3-dimensional aorto-mitral angle with Mitral Valve Quantification software and Doppler-derived pressure gradients.

Combining Machine Learning and Urine Oximetry: Towards an Intraoperative AKI Risk Prediction Algorithm.

Acute kidney injury (AKI) affects up to 50% of cardiac surgery patients. The definition of AKI is based on changes in serum creatinine relative to a baseline measurement or a decrease in urine output. These monitoring methods lead to a delayed diagnosis.

Intraoperative Urine Oxygen in Cardiac Surgery and 12-Month Outcomes.

Low intraoperative urinary oxygen during cardiac surgery is associated with increased risk of poor 12-month outcomes. With decreasing urinary oxygen thresholds, the risk of poor 12-month outcomes increases.