Percent Change In Artery Diameter Research Articles

Vascular Function after Sauna Bathing in Healthy Older Adults

Repeated heat exposure by immersion in warm water improves vascular function in healthy young adults. This observation could explain the health benefits of sauna bathing reported in population‐based studies, in which regular sauna sessions lasting more than 19 minutes were shown to significantly decrease the risk of cardiovascular mortality. However, it is unknown if such sauna durations improve vascular function in older adults. The purpose of this study was to determine if 20 min of sauna bathing acutely improves vascular function in healthy older adults.Six older adults (4 women) without cardiovascular disease and risk factors (age range: 57–71 yrs) underwent a sauna bathing session consisting of 2 bouts of 10 min in a dry Finnish sauna (80°C) separated by 10 min of seated rest outside the sauna. Prior to and following sauna bathing, flow‐mediated dilation (FMD) of the brachial artery in response to reactive hyperemia induced by 5 min of forearm ischemia was assessed by Doppler ultrasound after a minimum of 30 min rest in the supine position in a quiet and thermoneutral environment. The percent change in artery diameter from baseline to peak was used as an index of macrovascular function, whereas post‐occlusive reactive hyperemia (PORH), estimated by the brachial artery flow area‐under‐the‐curve above baseline during the 3 min following ischemia, was used to evaluate microvascular function. Heart rate (HR), mean arterial pressure (MAP), oral temperature (Toral) and mean skin temperature (Tsk) were monitored throughout the study.Sauna caused an increase in HR (55 ± 8 to 86 ± 10 bpm, P<0.01), mean Tsk (33.0 ± 0.5 to 40.7 ± 0.7°C, P<0.01) and Toral (36.7 ± 0.3 to 37.4 ± 0.2°C, P=0.025) while changes in MAP were not statistically different (100 ± 8 to 90 ± 4 mmHg, p=0.137). At the time of FMD assessment, HR (53 ± 5 and 52 ± 5 bpm, P=0.56), MAP (92 ± 6 and 90 ± 5 mmHg, P=0.59) and Toral (36.8 ± 0.3 and 36.9 ± 0.1 °C, P=0.27) were similar before and after sauna bathing, whereas mean Tsk was elevated prior to the post‐sauna FMD assessment (34.3 ± 0.4 vs. 32.9 ± 0.5°C, P<0.01). FMD was similar before and after sauna bathing (4.79 ± 2.21% vs. 4.86 ± 2.73%, P=0.93). PORH was also similar before and after sauna bathing (286 ± 198 vs. 380 ± 168 ml, P=0.18).These preliminary results indicate that macro‐ and microvascular functions are unaffected by two 10 min bouts of sauna bathing at 80°C in healthy older adults.Support or Funding InformationFunded by Fondation de l'Institut de cardiologie de Montréal and by Fonds de Recherche du Québec – Santé.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Prognostic value of flow-mediated dilatation following myocardial infarction

BackgroundRisk stratification for subsequent cardiovascular events following a myocardial infarction (MI) is an important area of research. Previous findings indicate flow-mediated dilatation (FMD) may be a valuable prognostic indicator. This study investigates the prognostic value of FMD in patients suffering an uncomplicated MI. MethodsOne hundred and seventy nine post-MI patients [110male/69 female, mean age: 64.8±10.0 years, ejection fraction: 51.9±12.2%] were included in this analysis. Ultrasound images of the brachial artery were used to determine FMD following reactive hyperemia. Subjects were tracked for subsequent cardiovascular events [myocardial infarction, heart failure, additional interventions (percutaneous coronary intervention, coronary artery bypass)] following data collection via medical chart review. ResultsThere were 45 subsequent cardiovascular events during a mean tracking period of 13.7 (±9.5) months. Receiver operating characteristic (ROC) curve analysis revealed a diagnosis of diabetes (ROC area: 0.67, p=0.001, 95% confidence interval: 0.58–0.77) and percent change in arterial diameter (ROC area: 0.63, p=0.01, 95% confidence interval: 0.53–0.73, optimal threshold: ≤/>4.5%) were prognostically significant. Kaplan–Meier analysis revealed the event-free survival rate for subjects without diabetes and an arterial diameter change >4.5%, without diabetes and percent change in arterial diameter ≤4.5%, with diabetes and percent change in arterial diameter >4.5% and with diabetes and percent change in arterial diameter ≤4.5% was 88.7%, 78.4%, 67.7% and 38.5%, respectively (Log-rank: 24.9, p<0.0001). ConclusionsNon-invasive FMD is a potential risk factor after MI and may add information to conventional risk stratification. This will need to be tested in further studies.

Relation between high-density lipoprotein cholesterol and peripheral vasomotor function

Low levels of high-density lipoprotein (HDL) cholesterol are one of the most common lipid abnormalities in patients with coronary artery disease. Endothelial dysfunction is also highly prevalent in patients with coronary artery disease. We sought to determine whether HDL cholesterol levels are correlated with endothelium-dependent vasomotion in patients being evaluated for atherosclerosis. Peripheral vascular endothelial function was assessed by high-resolution brachial artery ultrasound. Flow-mediated dilation (FMD) during reactive hyperemia was defined as the percent change in arterial diameter following 5-minute arterial occlusion. All patients underwent stress testing with nuclear single-photon emission computed tomographic imaging to determine percent left ventricular ejection fraction and define the presence or absence of coronary artery disease. One hundred fifty-one subjects (87 men, 64 women) were enrolled (average age 58 ± 11 years). Total cholesterol, HDL cholesterol, low-density lipoprotein cholesterol, and triglyceride levels were 188 ± 48, 47 ± 13, 108 ± 37 and 154 ± 88 mg/dl, respectively. The mean FMD for the entire group was 9.9 ± 5.2%. Subjects with an HDL cholesterol of <40 mg/dl (n = 39) had lower FMD (7.4 ± 3.6%) compared with those with an HDL cholesterol ≥40 mg/dl (11.0 ± 5.5%, p <0.001). There was a significant correlation between FMD and HDL cholesterol level (linear regression, p <0.001), and in multivariate analysis, HDL cholesterol was an independent predictor of FMD. Peripheral endothelial function was abnormal in subjects with low HDL cholesterol and well-preserved in those with high HDL cholesterol. These data suggest that impaired endothelial function associated with low HDL cholesterol may be an additional, previously unrecognized mechanism contributing to the increased risk of atherosclerosis in these patients.

Peripheral vascular endothelial function testing as a noninvasive indicator of coronary artery disease

OBJECTIVESWe studied whether assessment of endothelium-dependent vasomotion (EDV) with brachial artery ultrasound (BAUS) imaging predicts the presence or absence of coronary artery disease (CAD) as defined by exercise myocardial perfusion imaging (ExMPI).BACKGROUNDAbnormalities in EDV can be detected in arteries before the development of overt atherosclerosis, and its presence may predict poor long-term prognosis. Brachial artery ultrasound during reactive hyperemia is a noninvasive method of assessing peripheral EDV.METHODSClinically-indicated ExMPI along with BAUS were performed in 94 subjects (43 women, 51 men). Coronary artery disease was defined by myocardial ischemia or infarction on single photon emission computed tomography images. Flow-mediated dilation (FMD) after upper arm occlusion was defined as the percent change in arterial diameter during reactive hyperemia relative to the baseline.RESULTSSubjects with CAD by ExMPI (n = 23) had a lower FMD (6.3 ± 0.7%) than those without CAD by ExMPI (n = 71) (10.5 ± 0.6%; p = 0.0004). Flow-mediated dilation was highly predictive for CAD with an odds ratio of 1.32 for each percent decrease in FMD (p = 0.001). Based on a receiver-operator analysis, an FMD of 10% was used as a cut-point for further analysis. Twenty-one of 23 subjects who were positive for ExMPI had an FMD <10% (sensitivity 91%), whereas only two of 40 subjects with an FMD ≥10% were ExMPI-positive (negative predictive value: 95%). There was a correlation between the number of cardiac risk factors and FMD. Individuals with an FMD <10% exercised for a shorter duration than those with an FMD ≥10% (456 ± 24 vs. 544 ± 31 s, respectively; p = 0.02).CONCLUSIONSAssessment of EDV with BAUS has a high sensitivity and an excellent negative predictive value for CAD and, thus, has the potential for use as a screening tool to exclude CAD in low-risk subjects. Further standardization of BAUS is required, however, before specific cut-points for excluding CAD can be established.

Tamoxifen is not detrimental to endothelial function in postmenopausal women with breast cancer

Background Tamoxifen has mixed estrogen agonist and antagonist properties in estrogen-regulated tissues. Its effect on the cardiovascular system is not well defined. We carried out a study to investigate the effect of tamoxifen on peripheral vascular endothelial function. Methods Three groups of postmenopausal women (median age, 56 years; range, 39 to 69 years) with breast cancer were studied. Patients in group 1 (n = 10) were newly diagnosed with breast cancer and studied before and after 4 weeks treatment with tamoxifen. Group 2 women (n = 6) had been receiving long-term tamoxifen (3 to 5 years) and were studied while taking tamoxifen and 4 weeks after stopping it. The final group of 6 subjects were in remission from primary breast cancer and were not receiving or had previously received tamoxifen. Ultrasound assessments of endothelial function were done before and 4 weeks after the initiation or discontinuation of tamoxifen with the nontreatment group acting as control. All ultrasound imaging was made by a single investigator blinded to the therapeutic status of the subject. Brachial artery diameter was measured by ultrasound at baseline and 1 minute after reactive hyperemia. Flow-mediated reactivity (FMR) was defined as percent change in artery diameter from baseline 1 minute after reactive hyperemia. Results There was no change in FMR in patients before compared with 4 weeks after starting tamoxifen (4.06% ± 1.44% vs 3.97% ± 1.20%, respectively, mean ± standard error of the mean [SEM], P =.97). There was no significant change in FMR on withdrawal from tamoxifen (1.84% ± 1.98% vs –0.42% ± 1.44% on tamoxifen vs off tamoxifen, mean ± SEM, P =.36). FMR in subjects taking tamoxifen was no different from the control group (3.17% ± 1.05% vs 3.16% ± 0.91%, respectively, mean ± SEM, P =.995). Conclusions Tamoxifen does not appear to affect endothelial function in the short term in postmenopausal women with breast cancer. (Am Heart J 2001;142:e6.)

Variability in ultrasonic measurements of arterial stiffness in the atherosclerosis risk in communities study

Arterial stiffness is emerging as an important risk marker for cardiovascular disease. Ultrasound-based measurements of arterial stiffness are in use by several large epidemiological studies. The reliability of ultrasonic measurements of arterial stiffness was assessed as part of one of these, the Atherosclerosis Risk in communities (ARIC) study. ARIC, a prospective, four-center epidemiological study, used B-mode ultrasound with an electronic tracking device to measure arterial stiffness of the carotid artery. Oscillometric blood pressure measures were obtained before and after the arterial wall tracking. Measurement variability was estimated in 36 volunteers who were scanned at three visits conducted at 7- to 14-day intervals. Between- and within-person components of variation were estimated for arterial diameter and blood-pressure measurements. The correlation (R) between repeated measurements for pulse pressure, the percent change in arterial diameter (strain), and the percent and absolute change in the arterial area were 0.69, 0.67, 0.66 and 0.81, respectively. The R for the stress-strain elastic modulus (Ep), arterial distensibility, and arterial compliance were 0.66, 0.67, and 0.77, respectively. The R for the pressure-adjusted diameter change (i.e., diameter change adjusted for diastolic and pulse pressures) was 0.75. In summary, the ultrasonic measurements of arterial stiffness employed in the ARIC study demonstrate excellent short-term repeatability, demonstrating their utility in field settings.

Microcomputer-based analysis of cardiovascular indices

A microcomputer-based program has been developed which performs rapid and accurate acquisition of cardiovascular data from instrumented animals or isolated perfused hearts with concurrent analysis and display of the hemodynamic indices. The system allows real-time viewing of the data in four alternative graphic displays. These include: (1) a strip-charge type display of all channels; (2) a full screen display of any single channel; (3) display of pressuresegment length; and (4) trend graphs (cumulative change with time) of calculated hemodynamic indices such as heart rate, systolic and diastolic blood pressure, percent change in myocardial segment length, mean blood flow and percent change in arterial diameter. Precise analysis of both transient and steady-state events may be performed on any segment of data stored on the hard disk. The data at any point in the experiment may be accessed by cursoring through any trend graph of the derived indices, by recalling special event markers or by using the automatic time markers. The calculated results are printed and stored in ASCII files which can be transferred to spreadsheets, databases, graphics or statistical programs.