Cardiopulmonary Response to Exercise Testing in People with Chronic Stroke: A Retrospective Study

Background and Purpose. This study investigated the cardiopulmonary response and safety of exercise testing at peak effort in people during the chronic stage of stroke recovery. Methods. This retrospective study examined data from 62 individuals with chronic stroke (males: 32; mean (SD); age: (12.0) yr) participating in an exercise test. Results. Both males and females had low cardiorespiratory fitness levels. No significant differences were found between gender for peak HR (P = 0.27), or VO2 peak (P = 0.29). Males demonstrated higher values for minute ventilation, tidal volume, and respiratory exchange ratio. No major adverse events were observed in the exercise tests conducted. Discussion and Conclusion. There are differences between gender that may play a role in exercise testing performance and should be considered when developing exercise programs. The low VO2 peak of this cohort of chronic stroke survivors suggests the need for participation in exercise interventions

Reduced Cardiorespiratory Fitness after Stroke: Biological Consequences and Exercise-Induced Adaptations

Evidence from several studies consistently shows decline in cardiorespiratory (CR) fitness and physical function after disabling stroke. The broader implications of such a decline to general health may be partially understood through negative poststroke physiologic adaptations such as unilateral muscle fiber type shifts, impaired hemodynamic function, and decrements in systemic metabolic status. These physiologic changes also interrelate with reductions in activities of daily living (ADLs), community ambulation, and exercise tolerance, causing a perpetual cycle of worsening disability and deteriorating health. Fortunately, initial evidence suggests that stroke participants retain the capacity to adapt physiologically to an exercise training stimulus. However, despite this evidence, exercise as a therapeutic intervention continues to be clinically underutilized in the general stroke population. Far more research is needed to fully comprehend the consequences of and remedies for CR fitness impairments after stroke. The purpose of this brief review is to describe some of what is currently known about the physiological consequences of CR fitness decline after stroke. Additionally, there is an overview of the evidence supporting exercise interventions for improving CR fitness, and associated aspects of general health in this population

Coronary collateral perfusion in patients with coronary artery disease: effect of metoprolol

Background The use of ultrathin Doppler angioplasty guidewires has made it possible to measure collateral flow quantitatively. Pharmacologic interventions have been shown to influence collateral flow and, thus, to affect myocardial ischaemia. Methods Twenty-five patients with coronary artery disease undergoing PTCA were included in the present analysis. Coronary flow velocities were measured in the ipsilateral (\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} $n=25$ \end{document}) and contralateral (\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} $n=6$ \end{document}; two Doppler wires) vessels during PTCA with and without i.v. adenosine (140 μg/kg.min) before and 3 min after 5 mg metoprolol i.v., respectively. The ipsilateral Doppler wire was positioned distal to the stenosis, whereas the distal end of the contralateral wire was in an angiographically normal vessel. The flow signals of the ipsilateral wire were used to calculate the collateral flow index (CFI). CFI was defined as the ratio of flow velocity during balloon inflation divided by resting flow. Results Heart rate and mean aortic pressure decreased slightly (ns) after i.v. metoprolol. The collateral flow index was 0.25±0.12 (one fourth of the resting coronary flow) during the first PTCA and 0.27±0.14 (ns versus first PTCA) during the second PTCA, but decreased with metoprolol to 0.16±0.08 (\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} $p{<}0.0001$ \end{document} vs. baseline) during the third PTCA. Conclusions Coronary collateral flow increased slightly but not significantly during maximal vasodilatation with adenosine but decreased in 23 of 25 patients after i.v. metoprolol. Thus, there is a reduction in coronary collateral flow with metoprolol, probably due to an increase in coronary collateral resistance or a reduction in oxygen deman

Middle cerebral artery velocity dynamic response profile during exercise is attenuated following multiple ischemic strokes: A case report

A grant from the One-University Open Access Fund at the University of Kansas was used to defray the author's publication fees in this Open Access journal. The Open Access Fund, administered by librarians from the KU, KU Law, and KUMC libraries, is made possible by contributions from the offices of KU Provost, KU Vice Chancellor for Research & Graduate Studies, and KUMC Vice Chancellor for Research. For more information about the Open Access Fund, please see http://library.kumc.edu/authors-fund.xml.Blood flow regulation is impaired in people with stroke. However, the time course of change in middle cerebral artery velocity (MCAv) following repeated stroke at rest and during exercise remains unknown. In this case study, we provide novel characterization of the dynamic kinetic MCAv response profile to moderate‐intensity exercise before and after repeated ischemic MCA stroke. The initial stroke occurred in the left MCA. At 3 months poststroke, left MCAv amplitude (Amp) was ~50% lower than the right. At the 6‐month follow‐up visit, MCAv Amp declined in both MCA with the left MCAv Amp ~50% lower than the right MCAv Amp. Following a second right MCA stroke, we report further decline in Amp for the left MCA. At the 3‐ and 6‐month visit following the second stroke, the left MCAv Amp declined further (~10%). The right MCAv Amp dramatically decreased by 81.3% when compared to the initial study visit. The MCAv kinetic analysis revealed a marked impairment in the cerebrovascular response to exercise following stroke. We discuss potential pathophysiological mechanisms contributing to poststroke cerebrovascular dysfunction and the need to test therapeutic interventions (such as exercise) that might attenuate cerebrovascular decline in people following stroke.Eunice Kennedy Shriver National Institute of Child Health and Human Development (K01HD067318)CTSA grant from NCATS awarded to the University of Kansas for Frontiers: University of Kansas Clinical and Translational Science Institute (# UL1TR002366)CTSA Award # UL1TR000001 from NCRR and NCATSGeorgia Holland Endowment Fun

A Combined Measure of Vascular Risk for White Matter Lesions

This is the author's accepted manuscript.Background Though hypertension is a commonly studied risk factor for white matter lesions (WMLs), measures of blood pressure may fluctuate depending on external conditions resulting in measurement error. Indicators of arterial stiffening and reduced elasticity may be more sensitive indicators of risk for WMLs in aging; however the interdependent nature of vascular indicators creates statistical complications. Objective The purpose of the study was to determine whether a factor score comprised of multiple vascular indicators would be a stronger predictor of WMLs than traditional measures of blood pressure. Methods In a sample of well-characterized nondemented older adults, we used a factor analytic approach to account for variance common across multiple vascular measures while reducing measurement error. The result was a single factor score reflecting arterial stiffness and reduced elasticity. We used this factor score to predict white matter lesion volumes acquired via fluid attenuated inversion recovery (FLAIR) magnetic resonance imaging. Results The combined vascular factor score was a stronger predictor of deep WML (β = 0.42, p < 0.001) and periventricular WML volumes (β = 0.49, p < 0.001). After accounting for the vascular factor, systolic and diastolic blood pressure measurements were not significant predictors. Conclusions This suggests that a combined measure of arterial elasticity and stiffening may be a stronger predictor of WMLs than systolic and diastolic blood pressure accounting for the multicollinearity associated with a variety of interrelated vascular measures

Dose-Response of Aerobic Exercise on Cognition: A Community-Based, Pilot Randomized Controlled Trial

Epidemiological studies suggest a dose-response relationship exists between physical activity and cognitive outcomes. However, no direct data from randomized trials exists to support these indirect observations. The purpose of this study was to explore the possible relationship of aerobic exercise dose on cognition. Underactive or sedentary participants without cognitive impairment were randomized to one of four groups: no-change control, 75, 150, and 225 minutes per week of moderate-intensity semi-supervised aerobic exercise for 26-weeks in a community setting. Cognitive outcomes were latent residual scores derived from a battery of 16 cognitive tests: Verbal Memory, Visuospatial Processing, Simple Attention, Set Maintenance and Shifting, and Reasoning. Other outcome measures were cardiorespiratory fitness (peak oxygen consumption) and measures of function functional health. In intent-to-treat (ITT) analyses (n = 101), cardiorespiratory fitness increased and perceived disability decreased in a dose-dependent manner across the 4 groups. No other exercise-related effects were observed in ITT analyses. Analyses restricted to individuals who exercised per-protocol (n = 77) demonstrated that Simple Attention improved equivalently across all exercise groups compared to controls and a dose-response relationship was present for Visuospatial Processing. A clear dose-response relationship exists between exercise and cardiorespiratory fitness. Cognitive benefits were apparent at low doses with possible increased benefits in visuospatial function at higher doses but only in those who adhered to the exercise protocol. An individual’s cardiorespiratory fitness response was a better predictor of cognitive gains than exercise dose (i.e., duration) and thus maximizing an individual’s cardiorespiratory fitness may be an important therapeutic target for achieving cognitive benefits