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1.
Am Heart J ; 201: 164-167, 2018 07.
Article in English | MEDLINE | ID: mdl-29910050

ABSTRACT

In older patients (70 ± 7 years) with chronic well-compensated heart failure with preserved ejection and controlled blood pressure, 6 months treatment with aliskiren (direct renin inhibitor) showed non-significant trends for modest improvements in peak exercise oxygen consumption (14.9 ± 0.2 mL kg-1 min-1 versus 14.4 ± 0.2 mL kg-1 min-1; P = .10, trend) and ventilatory anaerobic threshold (888 ± 19 mL/min versus 841 ± 18 mL/min; P = .08).


Subject(s)
Amides/therapeutic use , Exercise Tolerance/drug effects , Fumarates/therapeutic use , Heart Failure/drug therapy , Randomized Controlled Trials as Topic/methods , Stroke Volume/physiology , Aged , Antihypertensive Agents , Blood Pressure/drug effects , Double-Blind Method , Female , Heart Failure/physiopathology , Humans , Male
2.
J Cardiovasc Magn Reson ; 20(1): 75, 2018 11 22.
Article in English | MEDLINE | ID: mdl-30463565

ABSTRACT

BACKGROUND: Current guidelines for assessing the risk of experiencing a hospitalized cardiovascular (CV) event discourage stress testing of asymptomatic individuals; however, these recommendations are based on evidence gathered primarily from those aged < 60 years, and do not address the possibility of unrecognized "silent myocardial ischemia" in middle aged and older adults. METHODS: We performed dobutamine cardiovascular magnetic resonance (CMR) stress testing in 327 consecutively recruited participants aged > 55 years without CV-related symptoms nor known coronary artery disease, but otherwise at increased risk for a future CV event due to pre-existing hypertension or diabetes mellitus for at least 5 years. After adjusting for the demographics and CV risk factors, log-rank test and Cox proportional hazards models determined the additional predictive value of the stress test results for forecasting hospitalized CV events/survival. Either stress-induced LV wall motion abnormalities or perfusion defects were used to indicate myocardial ischemia. RESULTS: Participants averaged 68 ± 8 years in age; 39% men, 75% Caucasian. There were 38 hospitalized CV events or deaths which occurred during a mean follow-up of 58 months. Using Kaplan-Meier analyses, myocardial ischemia identified future CV events/survival (p <  0.001), but this finding was more evident in men (p <  0.001) versus women (p = 0.27). The crude hazard ratio (HR) of myocardial ischemia for CV events/survival was 3.13 (95% CI: 1.64-5.93; p < 0.001). After accounting for baseline demographics, CV risk factors, and left ventricular ejection fraction/mass, myocardial ischemia continued to be associated with CV events/survival [HR: 4.07 (95% CI: 1.95-8.73) p < 0.001]. CONCLUSIONS: Among asymptomatic middle-aged individuals with risk factors for a sentinel CV event, the presence of myocardial ischemia during dobutamine CMR testing forecasted a future hospitalized CV event or death. Further studies are needed in middle aged and older individuals to more accurately characterize the prevalence, significance, and management of asymptomatic myocardial ischemia. TRIAL REGISTRATION: ( ClinicalTrials.gov identifier): NCT00542503 and was retrospectively registered on October 11th, 2007.


Subject(s)
Adrenergic beta-1 Receptor Agonists/administration & dosage , Dobutamine/administration & dosage , Magnetic Resonance Imaging/methods , Myocardial Ischemia/diagnostic imaging , Age Factors , Aged , Aged, 80 and over , Asymptomatic Diseases , Disease Progression , Female , Hospitalization , Humans , Male , Middle Aged , Myocardial Ischemia/mortality , Myocardial Ischemia/physiopathology , Myocardial Ischemia/therapy , Predictive Value of Tests , Prognosis , Prospective Studies , Risk Assessment , Risk Factors , Time Factors
3.
Am Heart J ; 185: 130-139, 2017 Mar.
Article in English | MEDLINE | ID: mdl-28267466

ABSTRACT

BACKGROUND: Acute decompensated heart failure (ADHF) is a leading cause of hospitalization in older persons in the United States. Reduced physical function and frailty are major determinants of adverse outcomes in older patients with hospitalized ADHF. However, these are not addressed by current heart failure (HF) management strategies and there has been little study of exercise training in older, frail HF patients with recent ADHF. HYPOTHESIS: Targeting physical frailty with a multi-domain structured physical rehabilitation intervention will improve physical function and reduce adverse outcomes among older patients experiencing a HF hospitalization. STUDY DESIGN: REHAB-HF is a multi-center clinical trial in which 360 patients ≥60 years hospitalized with ADHF will be randomized either to a novel 12-week multi-domain physical rehabilitation intervention or to attention control. The goal of the intervention is to improve balance, mobility, strength and endurance utilizing reproducible, targeted exercises administered by a multi-disciplinary team with specific milestones for progression. The primary study aim is to assess the efficacy of the REHAB-HF intervention on physical function measured by total Short Physical Performance Battery score. The secondary outcome is 6-month all-cause rehospitalization. Additional outcome measures include quality of life and costs. CONCLUSIONS: REHAB-HF is the first randomized trial of a physical function intervention in older patients with hospitalized ADHF designed to determine if addressing deficits in balance, mobility, strength and endurance improves physical function and reduces rehospitalizations. It will address key evidence gaps concerning the role of physical rehabilitation in the care of older patients, those with ADHF, frailty, and multiple comorbidities.


Subject(s)
Activities of Daily Living , Exercise Therapy/methods , Heart Failure/rehabilitation , Muscle Strength , Physical Endurance , Postural Balance , Acute Disease , Aged , Aged, 80 and over , Frail Elderly , Humans , Middle Aged , Physical Therapy Modalities , Walk Test
4.
Nitric Oxide ; 69: 78-90, 2017 Sep 30.
Article in English | MEDLINE | ID: mdl-28549665

ABSTRACT

Aerobic exercise training is an effective therapy to improve peak aerobic power (peak VO2) in individuals with hypertension (HTN, AHA/ACC class A) and heart failure patients with preserved ejection fraction (HFpEF). High nitrate containing beetroot juice (BRJ) also improves sub-maximal endurance and decreases blood pressure in both HTN and HFpEF. We hypothesized that combining an aerobic exercise and dietary nitrate intervention would result in additive or even synergistic positive effects on exercise tolerance and blood pressure in HTN or HFpEF. We report results from two pilot studies examining the effects of supervised aerobic exercise combined with dietary nitrate in patients with controlled HTN (n = 26, average age 65 ± 5 years) and in patients with HFpEF (n = 20, average age 69 ± 7 years). All patients underwent an aerobic exercise training regimen; half were randomly assigned to consume a high nitrate-containing beet juice beverage (BRJ containing 6.1 mmol nitrate for the HFpEF study consumed three times a week and 8 mmol nitrate for the HTN study consumed daily) while the other half consumed a beet juice beverage with the nitrate removed (placebo). The main result was that there was no added benefit observed for any outcomes when comparing BRJ to placebo in either HTN or HFpEF patients undergoing exercise training (p ≥ 0.14). There were within-group benefits. In the pilot study in patients with HFpEF, aerobic endurance (primary outcome), defined as the exercise time to volitional exhaustion during submaximal cycling at 75% of maximal power output, improved during exercise training within each group from baseline to end of study, 369 ± 149 s vs 520 ± 257 s (p = 0.04) for the placebo group and 384 ± 129 s vs 483 ± 258 s for the BRJ group (p = 0.15). Resting systolic blood pressure in patients with HFpEF also improved during exercise training in both groups, 136 ± 16 mm Hg vs 122 ± 3 mm Hg for the placebo group (p < 0.05) and 132 ± 12 mm Hg vs 119 ± 9 mm Hg for the BRJ group (p < 0.05). In the HTN pilot study, during a treadmill graded exercise test, peak oxygen consumption (primary outcome) did not change significantly, but time to exhaustion (also a primary outcome) improved in both groups, 504 ± 32 s vs 601 ± 38 s (p < 0.05) for the placebo group and 690 ± 38 s vs 772 ± 95 s for the BRJ group (p < 0.05) which was associated with a reduction in supine resting systolic blood pressure in BRJ group. Arterial compliance also improved during aerobic exercise training in both the HFpEF and the HTN patients for both BRJ and placebo groups. Future work is needed to determine if larger nitrate doses would provide an added benefit to supervised aerobic exercise in HTN and HFpEF patients.


Subject(s)
Dietary Supplements , Exercise , Heart Failure/physiopathology , Hypertension/physiopathology , Nitrates/administration & dosage , Aged , Beta vulgaris , Blood Pressure/drug effects , Female , Fruit and Vegetable Juices , Humans , Middle Aged , Nitrates/blood , Nitrites/blood , Oxygen/blood , Physical Endurance/drug effects , Stroke Volume/drug effects
5.
Br J Clin Pharmacol ; 83(3): 510-516, 2017 03.
Article in English | MEDLINE | ID: mdl-27639640

ABSTRACT

AIMS: To test the feasibility of a novel rivastigmine nasal spray as prospective treatment for dementia. METHODS: A single dose, crossover absolute bioavailability and safety study was conducted with rivastigmine intravenous solution (1 mg) and nasal spray (3.126 mg) in eight healthy elderly individuals, aged 58-75 years. RESULTS: Absolute bioavailability (F) of the nasal spray was significant at 0.62 (0.15) for F > 0 (P < 0.001, n = 8). The systemic dose absorbed was 2.0 (0.6) mg, time to maximum plasma concentration was 1.1 (0.5) h and maximum plasma concentration was 6.9 (2.0) ng ml-1 . The NAP226-90 to rivastigmine AUC0-∞ ratio was 0.78 (0.19). The single dose safety was good with two of five mild adverse events related to the nasal spray. Nasal and throat irritation were perceived as mild and transient, and both had resolved at 20 min post-nasal dose. An estimated dose of two or three sprays twice-daily with nasal spray would deliver comparable rivastigmine exposure and efficacy as a 6-9.7 mg day-1 oral dose and a 10 cm2 transdermal patch, respectively. CONCLUSIONS: The rivastigmine nasal spray had superior absolute bioavailability compared to historical values for oral capsule and transdermal patch determined by other researchers. It had rapid onset of action, low NAP226-90 to rivastigmine exposure ratio and a favourable safety and tolerability profile. The ability to achieve adjustable, individual, twice-daily dosing during waking hours has good potential to minimise undesirable cholinergic burden and sleep disturbances whilst delivering an effective dose for the treatment of dementia associated with Alzheimer's and Parkinson's disease.


Subject(s)
Rivastigmine/adverse effects , Rivastigmine/pharmacokinetics , Administration, Intravenous , Aged , Biological Availability , Cholinesterase Inhibitors/administration & dosage , Cholinesterase Inhibitors/adverse effects , Cholinesterase Inhibitors/pharmacokinetics , Cross-Over Studies , Female , Humans , Male , Middle Aged , Nasal Sprays , Rivastigmine/administration & dosage , Rivastigmine/blood
6.
Br J Nutr ; 115(2): 251-61, 2016 Jan 28.
Article in English | MEDLINE | ID: mdl-26615716

ABSTRACT

Numerous studies have examined relationships between disease biomarkers (such as blood lipids) and levels of circulating or cellular fatty acids. In such association studies, fatty acids have typically been expressed as the percentage of a particular fatty acid relative to the total fatty acids in a sample. Using two human cohorts, this study examined relationships between blood lipids (TAG, and LDL, HDL or total cholesterol) and circulating fatty acids expressed either as a percentage of total or as concentration in serum. The direction of the correlation between stearic acid, linoleic acid, dihomo-γ-linolenic acid, arachidonic acid and DHA and circulating TAG reversed when fatty acids were expressed as concentrations v. a percentage of total. Similar reversals were observed for these fatty acids when examining their associations with the ratio of total cholesterol:HDL-cholesterol. This reversal pattern was replicated in serum samples from both human cohorts. The correlations between blood lipids and fatty acids expressed as a percentage of total could be mathematically modelled from the concentration data. These data reveal that the different methods of expressing fatty acids lead to dissimilar correlations between blood lipids and certain fatty acids. This study raises important questions about how such reversals in association patterns impact the interpretation of numerous association studies evaluating fatty acids and their relationships with disease biomarkers or risk.


Subject(s)
Biomarkers/blood , Fatty Acids/blood , Lipids/blood , Adult , Black or African American , Aged , Arachidonic Acid/blood , Body Mass Index , Cholesterol/blood , Cholesterol, HDL/blood , Cholesterol, LDL/blood , Female , Humans , Linoleic Acid/blood , Male , Middle Aged , Overweight/blood , Risk Factors , Stearic Acids/blood , Triglycerides/blood , United States , White People
7.
J Cardiovasc Magn Reson ; 17: 103, 2015 Nov 25.
Article in English | MEDLINE | ID: mdl-26608545

ABSTRACT

BACKGROUND: Left ventricular wall motion abnormalities (LVWMA) observed during cardiovascular magnetic resonance (CMR) pharmacologic stress testing can be used to determine cardiac prognosis, but currently, information regarding the prognostic utility of upright maximal treadmill induced LVWMA is unknown. Our objective was to determine the prognostic utility of upright maximal treadmill exercise stress CMR. METHODS: One hundred and fifteen (115) men and women with known or suspected coronary arteriosclerosis and an appropriate indication for cardiovascular (CV) imaging to supplement ST segment stress testing underwent an upright treadmill exercise CMR stress test in which LVWMA were identified before and immediately after exercise. Personnel blinded to results determined the post-test incidence of cardiac events (cardiac death, myocardial infarctions [MI], and unstable angina warranting hospital admission or coronary arterial revascularization). RESULTS: All participants completed the testing protocol, with 90% completing image acquisition within 60 s of exercise cessation. MI or cardiac death occurred in 3% of individuals without and 17% of individuals with inducible LVWMA (p = 0.024). The combination of MI, cardiac death, and unstable angina warranting hospitalization occurred in 14% of individuals without and 47% of individuals with inducible LVWMA (p = 0.002). The addition of CMR imaging identified those at risk for future events (p = 0.002), as opposed to the electrocardiogram stress test alone (p = 0.63). CONCLUSIONS: In patients with or suspected of coronary arteriosclerosis and appropriate indication for imaging to supplement ST segment analysis during upright treadmill exercise, the presence of inducible LVWMA during treadmill exercise stress CMR supplements ST segment monitoring and helps identify those at risk of the future combined endpoints of myocardial infarction, cardiac death, and unstable angina warranting hospitalization.


Subject(s)
Coronary Artery Disease/diagnosis , Exercise Test/methods , Magnetic Resonance Imaging , Myocardial Contraction , Patient Positioning , Ventricular Dysfunction, Left/diagnosis , Ventricular Function, Left , Adult , Aged , Angina, Unstable/etiology , Coronary Artery Disease/complications , Coronary Artery Disease/mortality , Coronary Artery Disease/physiopathology , Coronary Artery Disease/therapy , Female , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Myocardial Infarction/etiology , Predictive Value of Tests , Prognosis , Retrospective Studies , Risk Assessment , Risk Factors , Severity of Illness Index , Ventricular Dysfunction, Left/etiology , Ventricular Dysfunction, Left/mortality , Ventricular Dysfunction, Left/physiopathology
8.
J Cardiovasc Magn Reson ; 17: 26, 2015 Apr 08.
Article in English | MEDLINE | ID: mdl-25885436

ABSTRACT

BACKGROUND: Dobutamine associated left ventricular (LV) wall motion analyses exhibit reduced sensitivity for detecting inducible ischemia in individuals with increased LV wall thickness. This study was performed to better understand the mechanism of this reduced sensitivity in the elderly who often manifest increased LV wall thickness and risk factors for coronary artery disease. METHODS: During dobutamine cardiovascular magnetic resonance (DCMR) stress testing, we assessed rate pressure product (RPP), aortic pulse wave velocity (PWV), LV myocardial oxygen demand (pressure volume area, PVA, mass, volumes, concentricity, and the presence of wall motion abnormalities (WMA) and first pass gadolinium enhanced perfusion defects (PDs) indicative of ischemia in 278 consecutively recruited individuals aged 69 ± 8 years with pre-existing or known risk factors for coronary artery disease. Each variable was assessed independently by personnel blinded to participant identifiers and analyses of other DCMR or hemodynamic variables. RESULTS: Participants were 80% white, 90% hypertensive, 43% diabetic and 55% men. With dobutamine, 60% of the participants who exhibited PDs had no inducible WMA. Among these participants, myocardial oxygen demand was lower than that observed in those who had both wall motion and perfusion abnormalities suggestive of ischemia (p = 0.03). Relative to those with PDs and inducible WMAs, myocardial oxygen demand remained different in these individuals with PDs without an inducible WMA after accounting for LV afterload and contractility (p = 0.02 and 0.03 respectively), but not after accounting for either LV stress related end diastolic volume index (LV preload) or resting concentricity (p = 0.31-0.71). CONCLUSIONS: During dobutamine stress testing, elderly patients experience increased LV concentricity and declines in LV preload and myocardial oxygen demand, all of which are associated with an absence of inducible LV WMAs indicative of myocardial ischemia. These findings provide insight as to why dobutamine associated wall motion analyses exhibit reduced sensitivity for identifying inducible ischemia in elderly. TRIAL REGISTRATION: This study was registered with Clinicaltrials.gov (NCT00542503).


Subject(s)
Cardiotonic Agents/administration & dosage , Coronary Circulation , Dobutamine/administration & dosage , Magnetic Resonance Imaging, Cine/methods , Myocardial Contraction , Myocardial Ischemia/diagnosis , Myocardial Perfusion Imaging/methods , Ventricular Function, Left , Age Factors , Aged , Aged, 80 and over , Contrast Media/administration & dosage , Female , Humans , Male , Middle Aged , Myocardial Ischemia/physiopathology , North Carolina , Oxygen Consumption , Predictive Value of Tests , Pulse Wave Analysis , Reproducibility of Results , Risk Factors , Ventricular Remodeling
9.
Am J Physiol Heart Circ Physiol ; 306(9): H1364-70, 2014 May.
Article in English | MEDLINE | ID: mdl-24658015

ABSTRACT

Heart failure (HF) with preserved ejection fraction (HFPEF) is the most common form of HF in older persons. The primary chronic symptom in HFPEF is severe exercise intolerance, and its pathophysiology is poorly understood. To determine whether skeletal muscle abnormalities contribute to their severely reduced peak exercise O2 consumption (Vo2), we examined 22 older HFPEF patients (70 ± 7 yr) compared with 43 age-matched healthy control (HC) subjects using needle biopsy of the vastus lateralis muscle and cardiopulmonary exercise testing to assess muscle fiber type distribution and capillarity and peak Vo2. In HFPEF versus HC patients, peak Vo2 (14.7 ± 2.1 vs. 22.9 ± 6.6 ml·kg(-1)·min(-1), P < 0.001) and 6-min walk distance (454 ± 72 vs. 573 ± 71 m, P < 0.001) were reduced. In HFPEF versus HC patients, the percentage of type I fibers (39.0 ± 11.4% vs. 53.7 ± 12.4%, P < 0.001), type I-to-type II fiber ratio (0.72 ± 0.39 vs. 1.36 ± 0.85, P = 0.001), and capillary-to-fiber ratio (1.35 ± 0.32 vs. 2.53 ± 1.37, P = 0.006) were reduced, whereas the percentage of type II fibers was greater (61 ± 11.4% vs. 46.3 ± 12.4%, P < 0.001). In univariate analyses, the percentage of type I fibers (r = 0.39, P = 0.003), type I-to-type II fiber ratio (r = 0.33, P = 0.02), and capillary-to-fiber ratio (r = 0.59, P < 0.0001) were positively related to peak Vo2. In multivariate analyses, type I fibers and the capillary-to-fiber ratio remained significantly related to peak Vo2. We conclude that older HFPEF patients have significant abnormalities in skeletal muscle, characterized by a shift in muscle fiber type distribution with reduced type I oxidative muscle fibers and a reduced capillary-to-fiber ratio, and these may contribute to their severe exercise intolerance. This suggests potential new therapeutic targets in this difficult to treat disorder.


Subject(s)
Exercise Tolerance , Heart Failure/physiopathology , Muscle, Skeletal/pathology , Stroke Volume , Aged , Capillaries/pathology , Case-Control Studies , Exercise , Female , Heart Failure/metabolism , Heart Failure/pathology , Humans , Male , Microcirculation , Muscle, Skeletal/blood supply , Muscle, Skeletal/physiopathology , Oxygen Consumption
10.
J Pediatr ; 164(6): 1376-83.e1, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24582483

ABSTRACT

OBJECTIVE: To examine the longitudinal associations between sex, diabetes self-care, and the health-related quality of life (HRQL) of children and adolescents with type 1 or type 2 diabetes. STUDY DESIGN: The sample included 910 participants with type 1 and 241 participants with type 2, ages 10-22 years at baseline, from the SEARCH for Diabetes in Youth Study, a longitudinal observational study. The primary outcome measure was the Pediatric Quality of Life Inventory. Repeated measures, mixed-model regression analysis was conducted with the use of data from baseline and at least one follow-up assessment, spanning approximately 4 years. RESULTS: HRQL was greater among those with type 1 versus type 2 diabetes. Among participants with type 1, greater (better) Pediatric Quality of Life Inventory total scores over time were related to greater parent education (P = .0007), lower glycated hemoglobin values (P < .0001), and greater physical activity during the past 7 days (P = .0001). There was a significant interaction between sex and age (P < .0001); girls' HRQL remained stable or decreased over time, whereas males' HRQL increased. For participants with type 2 diabetes, there was no significant interaction by age and sex, but lower total HRQL was related to being female (P = .011) and greater body mass index z-scores (P = .014). CONCLUSIONS: HRQL in this cohort varied by diabetes type. The interaction between sex and age for type 1 participants, coupled with poorer HRQL among female than male participants with type 2 diabetes, suggests the impacts of diabetes on HRQL differ by sex and should be considered in clinical management. Encouraging physical activity and weight control continue to be important in improving HRQL.


Subject(s)
Diabetes Mellitus, Type 1/therapy , Diabetes Mellitus, Type 2/therapy , Life Style , Patient Compliance/statistics & numerical data , Quality of Life , Self Care/standards , Adolescent , Age Factors , Attitude to Health , Body Mass Index , Child , Diabetes Mellitus, Type 1/diagnosis , Diabetes Mellitus, Type 1/psychology , Diabetes Mellitus, Type 2/diagnosis , Diabetes Mellitus, Type 2/psychology , Exercise , Female , Health Knowledge, Attitudes, Practice , Humans , Hypoglycemic Agents/administration & dosage , Longitudinal Studies , Male , Self Care/trends , Severity of Illness Index , Sex Factors , Young Adult
11.
J Cardiovasc Magn Reson ; 16: 17, 2014 Feb 03.
Article in English | MEDLINE | ID: mdl-24490671

ABSTRACT

BACKGROUND: Blood Oxygen Level Dependent (BOLD) magnetic resonance (MR) is a novel imaging tool that detects changes in tissue oxygenation. Increases in renal oxygenation in response to a standard 20 mg intravenous furosemide stimulus have been evaluated to assess kidney viability in patients with renal artery stenosis (RAS). The effect of prior exposure to furosemide on the ability of BOLD MR techniques to evaluate renal function is unknown.This study tested the hypothesis that chronic loop diuretic therapy is associated with attenuated responses in renal tissue oxygenation as measured by BOLD MR with an acute 20 mg intravenous furosemide stimulus in participants undergoing evaluation for RAS. METHODS: Thirty-eight participants referred for evaluation of RAS were recruited for this study. We examined renal cortical and medullary BOLD signal (T2*) intensities before and after a 20 mg intravenous furosemide stimulus. Additionally, we measured changes in renal artery blood flow using phase contrast techniques. RESULTS: After controlling for covariates age, race, gender, diabetes, glomerular filtration rate, body mass index, and stenosis severity, daily oral furosemide dose was an independent, negative predictor of renal medullary T2* response (p=0.01) to a standard 20 mg intravenous furosemide stimulus. Stenosis severity and ethnicity were also significant independent predictors of changes in T2* signal intensity in response to an acute furosemide challenge. Changes in renal blood flow in response to acute furosemide administration were correlated with changes in T2* in the renal cortex (r=0.29, p=0.03) but not the medulla suggesting changes in renal medullary oxygenation were not due to reduced renal medullary blood flow. CONCLUSIONS: Chronic furosemide therapy attenuates BOLD MR responses to an acute furosemide stimulus in patients with RAS being evaluated for renal artery revascularization procedures. Thus, patients who are chronically administered loop diuretics may need a different dosing strategy to accurately detect changes in renal oxygenation with BOLD MR in response to a furosemide stimulus.


Subject(s)
Furosemide , Magnetic Resonance Imaging , Oxygen/blood , Renal Artery Obstruction/diagnosis , Renal Artery/drug effects , Renal Circulation/drug effects , Sodium Potassium Chloride Symporter Inhibitors , Administration, Intravenous , Administration, Oral , Aged , Biomarkers/blood , Drug Administration Schedule , Female , Furosemide/administration & dosage , Humans , Male , Middle Aged , Predictive Value of Tests , Prospective Studies , Renal Artery/physiopathology , Renal Artery Obstruction/blood , Renal Artery Obstruction/physiopathology , Sodium Potassium Chloride Symporter Inhibitors/administration & dosage
12.
J Comput Assist Tomogr ; 38(3): 427-33, 2014.
Article in English | MEDLINE | ID: mdl-24651743

ABSTRACT

OBJECTIVE: The objective of this study was to assess the frequency and prognostic utility of small, short-duration left ventricular myocardial perfusion defects during dobutamine cardiovascular magnetic resonance (DCMR) stress imaging. METHODS: We performed first-pass contrast-enhanced DCMR at peak stress in 331 consecutively recruited individuals (aged 68 ± 8 years, 50% men) at intermediate risk for a future cardiac event. Size, location, and persistence of low-signal intensity perfusion defects were recorded. Cardiac events were assessed by personnel blinded to imaging results for a median of 24 months after the DCMR. RESULTS: Among the 55 individuals (16.6%) who exhibited small (<25% myocardial thickness) and short-duration (<5 frames in persistence) perfusion defects, diabetes was more prevalent (P = 0.019) and no cardiac events were observed. Large, persistent perfusion defects were associated with coronary artery disease, prior myocardial infarction, and decreased left ventricular function (P < 0.001 for all) and increased 2-year risk for a cardiac event (hazard ratio, 10.3; P < 0.001; confidence interval, 3.3-33.0). CONCLUSIONS: In individuals with diabetes, hypertension, or coronary artery disease at intermediate risk for a future cardiac event, small, short-duration DCMR perfusion defects are not associated with increased 2-year risk for a subsequent cardiac event.


Subject(s)
Cardiovascular Diseases/diagnosis , Cardiovascular Diseases/mortality , Dobutamine , Magnetic Resonance Angiography/statistics & numerical data , Myocardial Perfusion Imaging/statistics & numerical data , Aged , Aged, 80 and over , Exercise Test/statistics & numerical data , Female , Humans , Incidence , Magnetic Resonance Imaging, Cine , Male , Middle Aged , North Carolina/epidemiology , Prevalence , Prognosis , Reproducibility of Results , Risk Factors , Sensitivity and Specificity , Survival Rate , Vasodilator Agents
13.
J Gen Virol ; 94(Pt 2): 336-347, 2013 Feb.
Article in English | MEDLINE | ID: mdl-23136362

ABSTRACT

Toll-like receptor 7 (TLR7) recognizes guanidine-rich viral ssRNA and is an important mediator of peripheral immune responses to several ssRNA viruses. However, the role that TLR7 plays in regulating the innate immune response to ssRNA virus infections in specific organs such as the central nervous system (CNS) is not as clear. This study examined the influence of TLR7 on the neurovirulence of Langat virus (LGTV), a ssRNA tick-borne flavivirus. TLR7 deficiency did not substantially alter the onset or incidence of LGTV-induced clinical disease; however, it did significantly affect virus levels in the CNS with a log(10) increase in virus titres in brain tissue from TLR7-deficient mice. This difference in virus load was also observed following intracranial inoculation, indicating a direct effect of TLR7 deficiency on regulating virus replication in the brain. LGTV-induced type I interferon responses in the CNS were not dependent on TLR7, being higher in TLR7-deficient mice compared with wild-type controls. In contrast, induction of pro-inflammatory cytokines including tumour necrosis factor, CCL3, CCL4 and CXCL13 were dependent on TLR7. Thus, although TLR7 is not essential in controlling LGTV pathogenesis, it is important in controlling virus infection in neurons in the CNS, possibly by regulating neuroinflammatory responses.


Subject(s)
Encephalitis Viruses, Tick-Borne/immunology , Encephalitis Viruses, Tick-Borne/pathogenicity , Membrane Glycoproteins/immunology , Neurons/virology , Toll-Like Receptor 7/immunology , Virus Replication , Animals , Brain/virology , Cytokines/metabolism , Disease Models, Animal , Encephalitis, Tick-Borne/immunology , Encephalitis, Tick-Borne/pathology , Encephalitis, Tick-Borne/virology , Mice , Mice, Knockout , Viral Load
14.
Am J Physiol Regul Integr Comp Physiol ; 303(4): R368-75, 2012 Aug 15.
Article in English | MEDLINE | ID: mdl-22739352

ABSTRACT

Myogenic tone (MT) is a primary modulator of blood flow in the resistance vasculature of the brain, kidney, skeletal muscle, and perhaps in other high-flow organs such as the pregnant uterus. MT is known to be regulated by endothelium-derived factors, including products of the nitric oxide synthase (NOS) and/or the cyclooxygenase (COX) pathways. We asked whether pregnancy influenced MT in myometrial arteries (MA), and if so, whether such an effect could be attributed to alterations in NOS and/or COX. MA (200-300 µm internal diameter, 2-3 mm length) were isolated from 10 nonpregnant and 12 pregnant women undergoing elective hysterectomy or cesarean section, respectively. In the absence of NOS and/or COX inhibition, pregnancy was associated with increased MT in endothelium-intact MA compared with MA from nonpregnant women (P < 0.01). The increase in MT was not due to increased Ca(2+) entry via voltage-dependent channels since both groups of MA exhibited similar levels of constriction when exposed to 50 mM KCl. NOS inhibition (N(ω)-nitro-L-arginine methyl ester, L-NAME) or combined NOS/COX inhibition (L-NAME/indomethacin) increased MT in MA from pregnant women (P = 0.001 and P = 0.042, respectively) but was without effect in arteries from nonpregnant women. Indomethacin alone was without effect on MT in MA from either nonpregnant or pregnant women. We concluded that MT increases in MA during human pregnancy and that this effect was partially opposed by enhanced NOS activity.


Subject(s)
Arteries/physiology , Endothelium, Vascular/physiology , Myometrium/blood supply , Nitric Oxide Synthase/metabolism , Prostaglandin-Endoperoxide Synthases/metabolism , Vasoconstriction/physiology , Adult , Arteries/drug effects , Cyclooxygenase Inhibitors/pharmacology , Endothelium, Vascular/drug effects , Enzyme Inhibitors/pharmacology , Female , Humans , Indomethacin/pharmacology , Middle Aged , Myometrium/drug effects , Myometrium/metabolism , NG-Nitroarginine Methyl Ester/pharmacology , Pregnancy , Vasoconstriction/drug effects , Vasodilation/drug effects , Vasodilation/physiology
15.
J Comput Assist Tomogr ; 35(5): 614-7, 2011.
Article in English | MEDLINE | ID: mdl-21926858

ABSTRACT

OBJECTIVE: During cardiovascular stress, if right ventricular (RV) stroke volume exceeds left ventricular (LV) stroke volume, then a large volume of blood is displaced into the pulmonary circulation that may precipitate pulmonary edema. We sought to determine the metrics by which cardiovascular magnetic resonance (CMR) could measure simultaneous displacement of RV and LV stroke volumes during dobutamine stress. METHODS: Thirteen healthy subjects (5 women) aged 53 ± 10 years without medical conditions and taking no medications underwent 2 CMR examinations at 1.5 T separated by 4 to 8 weeks in which RV and LV stroke volumes were determined during intravenous dobutamine and atropine infused to achieve 80% of the maximum predicted heart rate response for age. RESULTS: The RV and LV stroke volumes were highly correlated at each level of stress (rest: r = 0.98, P = 0.007; low stress: r = 0.87, P = 0.001; and peak stress: r = 0.88, P = 0.001), and the mean difference in SV at each level of stress (rest, low stress, and peak stress was 0 to 2 mL on examinations 1 and 2. CONCLUSIONS: Simultaneous change in right and left ventricular stroke volumes can be assessed in a highly reproducible manner throughout the course of dobutamine CMR stress administered to achieve 80% of maximum predicted heart rate response for age. This technology may help identify discrepancies in RV and LV stroke volumes during cardiovascular stress that are associated with the development of pulmonary edema.


Subject(s)
Cardiotonic Agents , Dobutamine , Magnetic Resonance Imaging/methods , Stroke Volume/physiology , Ventricular Function, Left/physiology , Ventricular Function, Right/physiology , Adult , Atropine , Exercise Test , Female , Heart Rate/physiology , Humans , Image Processing, Computer-Assisted , Male , Middle Aged
16.
J Cardiovasc Magn Reson ; 11: 25, 2009 Aug 03.
Article in English | MEDLINE | ID: mdl-19650895

ABSTRACT

BACKGROUND: To determine if patients without dobutamine induced left ventricular wall motion abnormalities (WMA) but an increased LV end-diastolic wall thickness (EDWT) exhibit a favorable cardiac prognosis. RESULTS: Between 1999 and 2001, 175 patients underwent a dobutamine stress cardiovascular magnetic resonance (DCMR) procedure utilizing gradient-echo cines. Participants had a LV ejection fraction >55% without evidence of an inducible WMA during peak dobutamine/atropine stress. After an average of 5.5 years, all participants were contacted and medical records were reviewed to determine the post-DCMR occurrence of cardiac death, myocardial infarction (MI), and unstable angina (USA) or congestive heart failure (CHF) warranting hospitalization.In a multivariate analysis, that took into account Framingham and other risk factors associated with cardiac events, a cine gradient-echo derived LV EDWT > or =12 mm was associated independently with an increase in cardiac death and MI (HR 6.0, p = 0.0016), and the combined end point of MI, cardiac death, and USA or CHF warranting hospitalization (HR 3.0, p = 0.0005). CONCLUSION: Similar to echocardiography, CMR measures of increased LV wall thickness should be considered a risk factor for cardiac events in individuals receiving negative reports of inducible ischemia after dobutamine stress. Additional prognostic studies of the importance of LV wall thickness and mass measured with steady-state free precession techniques are warranted.


Subject(s)
Adrenergic beta-Agonists , Cardiovascular Diseases/etiology , Dobutamine , Magnetic Resonance Imaging, Cine , Myocardial Contraction , Stroke Volume , Ventricular Dysfunction, Left/diagnosis , Aged , Aged, 80 and over , Angina, Unstable/etiology , Cardiovascular Diseases/mortality , Cardiovascular Diseases/physiopathology , Female , Heart Failure/etiology , Hospitalization , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Myocardial Infarction/etiology , Observer Variation , Predictive Value of Tests , Prognosis , Proportional Hazards Models , Risk Assessment , Risk Factors , Time Factors , Ventricular Dysfunction, Left/complications , Ventricular Dysfunction, Left/mortality , Ventricular Dysfunction, Left/physiopathology
17.
Alcohol ; 66: 1-7, 2018 02.
Article in English | MEDLINE | ID: mdl-29277282

ABSTRACT

Laboratory tests can play an important role in assessment of alcoholic patients, including for evaluation of liver damage and as markers of alcohol intake. Evidence on test performance should lead to better selection of appropriate tests and improved interpretation of results. We compared laboratory test results from 1578 patients between cases (with alcoholic cirrhosis; 753 men, 243 women) and controls (with equivalent lifetime alcohol intake but no liver disease; 439 men, 143 women). Comparisons were also made between 631 cases who had reportedly been abstinent from alcohol for over 60 days and 364 who had not. ROC curve analysis was used to estimate and compare tests' ability to distinguish patients with and without cirrhosis, and abstinent and drinking cases. The best tests for presence of cirrhosis were INR and bilirubin, with areas under the ROC curve (AUCs) of 0.91 ± 0.01 and 0.88 ± 0.01, respectively. Confining analysis to patients with no current or previous ascites gave AUCs of 0.88 ± 0.01 for INR and 0.85 ± 0.01 for bilirubin. GGT and AST showed discrimination between abstinence and recent drinking in patients with cirrhosis, including those without ascites, when appropriate (and for GGT, sex-specific) limits were used. For AST, a cut-off limit of 85 units/L gave 90% specificity and 37% sensitivity. For GGT, cut-off limits of 288 units/L in men and 138 units/L in women gave 90% specificity for both and 40% sensitivity in men, 63% sensitivity in women. INR and bilirubin show the best separation between patients with alcoholic cirrhosis (with or without ascites) and control patients with similar lifetime alcohol exposure. Although AST and GGT are substantially increased by liver disease, they can give useful information on recent alcohol intake in patients with alcoholic cirrhosis when appropriate cut-off limits are used.


Subject(s)
Alcohol Abstinence , Alcohol Drinking/blood , Bilirubin/blood , Clinical Enzyme Tests , International Normalized Ratio , Liver Cirrhosis, Alcoholic/blood , Liver Cirrhosis, Alcoholic/diagnosis , Liver Function Tests/methods , Adult , Alcohol Drinking/adverse effects , Alcohol Drinking/prevention & control , Area Under Curve , Aspartate Aminotransferases/blood , Biomarkers/blood , Case-Control Studies , Europe , Female , Humans , Liver Cirrhosis, Alcoholic/etiology , Male , Middle Aged , Predictive Value of Tests , ROC Curve , Reproducibility of Results , Risk Factors , Sex Factors , United States , gamma-Glutamyltransferase/blood
18.
Neurorehabil Neural Repair ; 21(6): 568-73, 2007.
Article in English | MEDLINE | ID: mdl-17522261

ABSTRACT

BACKGROUND: Recovery of motor function after stroke may be associated with changes in inhibitory and facilitatory circuits within the motor cortex. OBJECTIVE: We explored such changes longitudinally after stroke, using transcranial magnetic stimulation (TMS). METHODS: Subjects (N = 27) with a single cerebral infarction affecting movement of either hand were studied at <10 days poststroke, 1 month, and 6 months. Age-matched control subjects (N = 9) were studied at 2 times. RESULTS: In contrast to previous studies, paired-pulse inhibition was increased in patients with a subcortical stroke compared to control subjects. After a cortical stroke, paired-pulse facilitation was also increased. Stroke location affected the time course of inhibition. Subcortical stroke resulted in increased inhibition initially that decreased over time, whereas cortical stroke had no significant effect on inhibition and a more immediate and lasting effect on facilitation. CONCLUSIONS: The time course of a decline in inhibition based on TMS after subcortical stroke followed the gain in motor recovery. Increased facilitation in cortical stroke patients is more likely to represent the effect of early cortical circuit disruption and may not play a role in subacute changes in motor function.


Subject(s)
Motor Cortex/physiology , Recovery of Function/physiology , Stroke/physiopathology , Transcranial Magnetic Stimulation , Aged , Cerebral Infarction/physiopathology , Female , Follow-Up Studies , Functional Laterality/physiology , Humans , Male , Middle Aged , Neural Inhibition/physiology
19.
J Am Geriatr Soc ; 65(11): 2374-2382, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28542926

ABSTRACT

OBJECTIVES: To evaluate the effects of an aldosterone antagonist on exercise intolerance in older adults with heart failure and preserved ejection fraction (HFpEF). DESIGN: Randomized, placebo-controlled, double-blind trial. SETTING: Academic medical center, Winston-Salem, North Carolina. PARTICIPANTS: Older adults (N = 80, aged 71 ± 1; 80% female) with stable compensated HFpEF and controlled blood pressure (BP). MEASUREMENTS: Participants were randomized into a 9-month treatment of spironolactone 25 mg/d vs placebo. Assessments were peak exercise oxygen consumption (VO2 ), 6-minute walk test, Minnesota Living with Heart Failure Questionnaire (MLHFQ), cardiac magnetic resonance imaging, Doppler echocardiography, and vascular ultrasound. RESULTS: Seventy-one participants completed the trial: 37 in the spironolactone group and 34 in the placebo group. Adherence according to pill count was excellent (spironolactone 95%, placebo 97%). Mean spironolactone dose was 24.3 ± 2.9 mg/d and was well tolerated. Spironolactone significantly reduced systolic and diastolic BP at rest and peak exercise. At 9-month follow-up, baseline-adjusted peak VO2, the primary outcome, was 13.5 ± 0.3 mL/kg per minute in the spironolactone group versus 13.9 ± 0.3 mL/kg per minute in the placebo group (adjusted mean difference -0.4 mL/kg per minute; 95% confidence interval = -1.1-0.4 mL/kg per minute; P = .38). The 95% confidence intervals of spironolactone's effect on peak VO2 (-8.2% to 3.2%) excluded a clinically significant beneficial effect. There were also no significant differences in 6-minute walk distance, arterial stiffness, left ventricular (LV) mass, LV mass/end-diastolic volume, or MLHFQ score. CONCLUSION: In older adults with stable compensated HFpEF, 9 months of spironolactone 25 mg/d was well tolerated and reduced BP but did not improve exercise capacity, quality of life, LV mass, or arterial stiffness.


Subject(s)
Coronary Vessels/drug effects , Exercise Tolerance/drug effects , Heart Failure, Diastolic/drug therapy , Mineralocorticoid Receptor Antagonists/administration & dosage , Spironolactone/administration & dosage , Aged , Aged, 80 and over , Double-Blind Method , Echocardiography , Exercise Test , Female , Humans , Male , Risk Assessment , Stroke Volume/drug effects
20.
JACC Heart Fail ; 5(5): 359-366, 2017 05.
Article in English | MEDLINE | ID: mdl-28285121

ABSTRACT

OBJECTIVES: This study sought to assess a novel physical rehabilitation intervention in older patients hospitalized for acute decompensated heart failure (ADHF). BACKGROUND: After ADHF, older patients, who are frequently frail with multiple comorbidities, have prolonged and incomplete recovery of physical function and remain at high risk for poor outcomes. METHODS: The REHAB-HF (Rehabilitation Therapy in Older Acute Heart Failure Patients) pilot study was a 3-site, randomized, attention-controlled pilot study of a tailored, progressive, multidomain physical rehabilitation intervention beginning in the hospital and continuing for 12 weeks post-discharge in patients ≥60 years hospitalized with ADHF. The primary purpose was to assess the feasibility and reasonableness of the hypothesis that the novel rehabilitation intervention would improve physical function (Short Physical Performance Battery [SPPB]) over 3 months and reduce all-cause rehospitalizations over 6 months. RESULTS: The study enrolled 27 patients with ADHF (ages 60 to 98 years; 59% women; 56% African American; 41% with preserved ejection fraction [≥45%]). At baseline, participants had marked impairments in physical function, multiple comorbidities, and frailty. Study retention (89%) and intervention adherence (93%) were excellent. At 3 months, an intervention effect size was measured for the SPPB score of +1.1 U (7.4 ± 0.5 U vs. 6.3 ± 0.5 U), and at 6 months an effect size was observed for an all-cause rehospitalization rate of -0.48 (1.16 ± 0.35 vs. 1.64 ± 0.39). The change in SPPB score was strongly related to all-cause rehospitalizations, explaining 91% of change. CONCLUSIONS: These findings support the feasibility and rationale for a recently launched, National Institutes of Health-funded trial to test the safety and efficacy of this novel multidomain physical rehabilitation intervention to improve physical function and reduce rehospitalizations in older, frail patients with ADHF with multiple comorbidities. (Rehabilitation and Exercise Training After Hospitalization [REHAB-HF]; NCT01508650; A Trial of Rehabilitation Therapy in Older Acute Heart Failure Patients [REHAB-HF]; NCT02196038).


Subject(s)
Exercise Therapy/methods , Exercise Tolerance/physiology , Heart Failure/rehabilitation , Hospitalization , Stroke Volume/physiology , Acute Disease , Aged , Aged, 80 and over , Continuity of Patient Care , Female , Follow-Up Studies , Heart Failure/diagnosis , Humans , Length of Stay , Male , Middle Aged , Oxygen Consumption/physiology , Patient Discharge , Pilot Projects , Risk Assessment , Severity of Illness Index , Treatment Outcome
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