Pulsatility and flow patterns across macro- and microcirculatory arteries of continuous-flow left ventricular assist device patients.

BACKGROUND: Reduced arterial pulsatility in continuous-flow left ventricular assist devices (CF-LVAD) patients has been implicated in clinical complications. Consequently, recent improvements in clinical outcomes have been attributed to the "artificial pulse" technology inherent to the HeartMate3 (HM3) LVAD. However, the effect of the "artificial pulse" on arterial flow, transmission of pulsatility into the microcirculation and its association with LVAD pump parameters is not known. METHODS: The local flow oscillation (pulsatility index, PI) of common carotid arteries (CCAs), middle cerebral arteries (MCAs) and central retinal arteries (CRAs-representing the microcirculation) were quantified by 2D-aligned, angle-corrected Doppler ultrasound in 148 participants: healthy controls, n = 32; heart failure (HF), n = 43; HeartMate II (HMII), n = 32; HM3, n = 41. RESULTS: In HM3 patients, 2D-Doppler PI in beats with "artificial pulse" and beats with "continuous-flow" was similar to that of HMII patients across the macro- and microcirculation. Additionally, peak systolic velocity did not differ between HM3 and HMII patients. Transmission of PI into the microcirculation was higher in both HM3 (during the beats with "artificial pulse") and in HMII patients compared with HF patients. LVAD pump speed was inversely associated with microvascular PI in HMII and HM3 (HMII, r2 = 0.51, p < 0.0001; HM3 "continuous-flow," r2 = 0.32, p = 0.0009; HM3 "artificial pulse," r2 = 0.23, p = 0.007), while LVAD pump PI was only associated with microcirculatory PI in HMII patients. CONCLUSIONS: The "artificial pulse" of the HM3 is detectable in the macro- and microcirculation but without creating a significant alteration in PI compared with HMII patients. Increased transmission of pulsatility and the association between pump speed and PI in the microcirculation indicate that the future clinical care of HM3 patients may involve individualized pump settings according to the microcirculatory PI in specific end-organs.

The Timed Up and Go test predicts frailty in patients with COPD.

The Timed Up and Go (TUG) is a global measure of mobility and has the ability to detect frail individuals. Frail patients with chronic obstructive pulmonary disease (COPD) are usually undiagnosed. We hypothesised that the TUG would identify frail patients with COPD. Frailty was assessed in 520 patients diagnosed with COPD and 150 controls using a Comprehensive Geriatric Assessment questionnaire and frailty index (FI) was derived. The TUG was used to assess physical mobility. All participants were assessed for lung function and body composition. A ROC curve was used to identify how well TUG discriminates between frail and non-frail patients with COPD. The patients with COPD and controls were similar in age, sex and BMI but the patients with COPD were more frail, mean ± SD FI 0.16 ± 0.08 than controls 0.05 ± 0.03, P < 0.001. Frail patients with COPD had a greater TUG time (11.55 ± 4.03 s) compared to non-frail patients (9.2 ± 1.6 sec), after controlling for age and lung function (F = 15.94, P < 0.001), and both were greater than the controls (8.3 ± 1.2 sec), P < 0.001. The TUG discriminated between frail and non-frail patients with COPD with an area under the curve of 72 (95% CI: 67-76), and a diagnostic odds ratio of 2.67 (95% CI:1.5-4.6), P < 0.001. The TUG showed the ability to discriminate between frail and non-frail patients with COPD, independent of age and severity of the airflow obstruction. The TUG is a simple, easy and quick measure that could be easily applied in restricted settings to screen for frailty in COPD.

Quantitative 18F-fluorodeoxyglucose positron emission tomography/computed tomography to assess pulmonary inflammation in COPD.

RATIONALE: COPD and smoking are characterised by pulmonary inflammation. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) imaging may improve knowledge of pulmonary inflammation in COPD patients and aid early development of novel therapies as an imaging biomarker. OBJECTIVES: To evaluate pulmonary inflammation, assessed by FDG uptake, in whole and regional lung in "usual" (smoking-related) COPD patients, alpha-1 antitrypsin deficiency (α1ATD) COPD patients, smokers without COPD and never-smokers using FDG PET/CT. Secondly, to explore cross-sectional associations between FDG PET/CT and systemic inflammatory markers in COPD patients and repeatability of the technique in COPD patients. METHODS: Data from two imaging studies were evaluated. Pulmonary FDG uptake (normalised Ki; nKi) was measured by Patlak graphical analysis in four subject groups: 84 COPD patients, 11 α1ATD-COPD patients, 12 smokers and 10 never-smokers. Within the COPD group, associations between nKi and systemic markers of inflammation were assessed. Repeatability was evaluated in 32 COPD patients comparing nKi values at baseline and at 4-month follow-up. RESULTS: COPD patients, α1ATD-COPD patients and smokers had increased whole lung FDG uptake (nKi) compared with never-smokers (0.0037±0.001, 0.0040±0.001, 0.0040±0.001 versus 0.0028±0.001 mL·cm-3·min-1, respectively, p<0.05 for all). Similar results were observed in upper and middle lung regions. In COPD participants, plasma fibrinogen was associated with whole lung nKi (ß=0.30, p=0.02) in multivariate analysis adjusted for current smoking, forced expiratory volume in 1 s % predicted, systemic neutrophils and C-reactive protein levels. Mean percentage difference in nKi between the baseline and follow-up was 3.2%, and the within subject coefficient of variability was 7.7%. CONCLUSIONS: FDG PET/CT has potential as a noninvasive tool to enable whole lung and regional quantification of FDG uptake to assess smoking- and COPD-related pulmonary inflammation.

Cerebral vasoreactivity in HeartMate 3 patients.

BACKGROUND: While rates of stroke have declined with the HeartMate3 (HM3) continuous- flow (CF) left ventricular assist device (LVAD), the impact of non-pulsatile flow and artificial pulse physiology on cerebrovascular function is not known. We hypothesized that improved hemodynamics and artificial pulse physiology of HM3 patients would augment cerebrovascular metabolic reactivity (CVR) compared with HeartMate II (HMII) CF-LVAD and heart failure (HF) patients. METHODS: Mean, peak systolic and diastolic flow velocities (MFV, PSV, MinFV, respectively) and cerebral pulsatility index were determined in the middle cerebral artery (MCA) before and after a 30 sec breath-hold challenge in 90 participants: 24 healthy controls; 30 HF, 15 HMII, and 21 HM3 patients. RESULTS: In HM3 patients, breath-holding increased MFV (Δ8 ± 10 cm/sec, p < .0001 vs baseline) to levels similar to HF patients (Δ9 ± 8 cm/sec, p > .05), higher than HMII patients (Δ2 ± 8 cm/sec, p < .01) but lower than healthy controls (Δ13 ± 7 cm/sec, p < .05). CF-LVAD altered the proportion of systolic and diastolic flow responses as reflected by a differential cerebral pulsatility index (p = .03). Baseline MFV was not related to CVR (r2 = 0.0008, p = .81). However, CF-LVAD pump speed was strongly inversely associated with CVR in HM II (r2 = 0.51, p = .003) but not HM3 patients (r2 = 0.01, p = .65). CONCLUSIONS: Compared with HMII, HM3 patients have a significantly improved CVR. However, CVR remains lower in HM3 and HF patients than in healthy controls, therefore suggesting that changes in cerebral hemodynamics are not reversed by CF-LVAD therapy. Further research on the mechanisms and the long-term impact of altered cerebral hemodynamics in this unique patient population are warranted.

May Measurement Month 2019: an analysis of blood pressure screening results from the United Kingdom and Republic of Ireland.

In the UK, heart and circulatory diseases account for 29% of all deaths (14% through coronary heart disease and 8% through stroke). In 2015, the prevalence of hypertension was 20% in the UK and 23% in the Republic of Ireland. In 2019, 14% of people registered with a UK general practice had hypertension and yet it was the attributable risk factor for around half of all deaths from coronary heart disease or stroke. We participated in May Measurement Month 2019 to increase awareness of blood pressure (BP) measurement, and to identify the proportion of undiagnosed hypertension and degree of uncontrolled hypertension in the community. The 2019 campaign set up screening sites within the community at places of worship, supermarkets, GP surgeries, workplaces, charity events, community pharmacies, gyms, and various other public places. We screened 10194 participants (mean age 51 ± 18 years, 60% women) and found that 1013 (9.9%) were on antihypertensive treatment, while 3408 (33.4%) had hypertension. Of the 3408 participants with hypertension, only 33.5% were aware of their condition despite 98.8% having previous BP measurements. In those on antihypertensive medication, only 38.2% had controlled BP (<140 and <90 mmHg). Our UK and Republic of Ireland data demonstrate concerning levels of undiagnosed hypertension and sub-optimal BP control in many individuals with a diagnosis. This evidence supports a critical need for better systematic community and primary care screening initiatives.

Increased Aortic Stiffness Is Associated With Higher Rates of Stroke, Gastrointestinal Bleeding and Pump Thrombosis in Patients With a Continuous Flow Left Ventricular Assist Device.

BACKGROUND: In the general population, increased aortic stiffness is associated with an increased risk of cardiovascular events. Previous studies have demonstrated an increase in aortic stiffness in patients with a continuous flow left ventricular assist device (CF-LVAD). However, the association between aortic stiffness and common adverse events is unknown. METHODS AND RESULTS: Forty patients with a HeartMate II (HMII) (51 $ 11 years; 20% female; 25% ischemic) implanted between January 2011 and September 2017 were included. Two-dimensional transthoracic echocardiograms of the ascending aorta, obtained before HMII placement and early after heart transplant, were analyzed to calculate the aortic stiffness index (AO-SI). The study cohort was divided into patients who had an increased vs decreased AO-SI after LVAD support. A composite outcome of gastrointestinal bleeding, stroke, and pump thrombosis was defined as the primary end point and compared between the groups. While median AO-SI increased significantly after HMII support (AO-SI 4.4-6.5, P = .012), 16 patients had a lower AO-SI. Patients with increased (n = 24) AO-SI had a significantly higher rate of the composite end point (58% vs 12%, odds ratio 9.8, P < .01). Similarly, those with increased AO-SI tended to be on LVAD support for a longer duration, had higher LVAD speed and reduced use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers. CONCLUSIONS: Increased aortic stiffness in patients with a HMII is associated with a significantly higher rates of adverse events. Further studies are warranted to determine the causality between aortic stiffness and adverse events, as well as the effect of neurohormonal modulation on the conduit vasculature in patients with a CF-LVAD.

Short physical performance battery as a practical tool to assess mortality risk in chronic obstructive pulmonary disease.

RATIONALE: chronic obstructive pulmonary disease (COPD) is a leading cause of mortality and common in older adults. The BODE Index is the most recognised mortality risk score in COPD but includes a 6-minute walk test (6MWT) that is seldom available in practise; the BODE Index may be better adopted if the 6MWT was replaced. OBJECTIVES: we investigated whether a modified BODE Index in which 6MWT was replaced by an alternative measure of physical capacity, specifically the short physical performance battery (SPPB) or components, retained its predictive ability for mortality in individuals with COPD. METHODS: we analysed 630 COPD patients from the ERICA cohort study for whom UK Office for National Statistics verified mortality data were available. Variables tested at baseline included spirometry, 6MWT, SPPB and its components (4-m gait speed test [4MGS], chair stand and balance). Predictive models were developed using stratified multivariable Cox regression, and assessed by C-indices and calibration plots with 10-fold cross-validation and replication. RESULTS: during median 2 years of follow-up, 60 (10%) individuals died. There was no significant difference between the discriminative ability of BODE6MWT (C-index 0.709, 95% confidence interval [CI], 0.680-0.737), BODESPPB (C-index 0.683, 95% CI, 0.647-0.712), BODE4MGS (C-index 0.676, 95% CI, 0.643-0.700) and BODEBALANCE (C-index 0.686, 95% CI, 0.651-0.713) for predicting mortality. CONCLUSIONS: the SPPB, and its 4MGS and balance components, can potentially be used as an alternative to the 6MWT in the BODE Index without significant loss of predictive ability in all-cause mortality.

Cardiac Responses to Submaximal Isometric Contraction and Aerobic Exercise in Healthy Pregnancy.

PURPOSE: The increased physiological demand of pregnancy results in the profound adaptation of the maternal cardiovascular system, reflected by greater resting cardiac output and left ventricular (LV) deformation. Whether the increased resting demand alters acute cardiac responses to exercise in healthy pregnant women is not well understood. METHODS: Healthy nonpregnant (n = 18), pregnant (n = 14, 22-26 wk gestation), and postpartum women (n = 13, 12-16 wk postdelivery) underwent assessments of cardiac function and LV mechanics at rest, during a sustained isometric forearm contraction (30% maximum), and during low-intensity (LOW) and moderate-intensity (MOD) dynamic cycling exercise (25% and 50% peak power output). Significant differences (α = 0.05) were determined using ANCOVA and general linear model (resting value included as covariate). RESULTS: When accounting for higher resting cardiac output in pregnant women, pregnant women had greater cardiac output during isometric contraction (2.0 ± 0.3 L·min-1·m-1.83; nonpregnant, 1.3 ± 0.2 L·min-1·m-1.83; postpartum, 1.5 ± 0.5 L·min-1·m-1.83; P = 0.02) but similar values during dynamic cycling exercise (pregnant, LOW = 2.8 ± 0.4 L·min-1·m-1.83, MOD = 3.4 ± 0.7 L·min-1·m-1.83; nonpregnant, LOW = 2.4 ± 0.3 L·min-1·m-1.83, MOD = 3.0 ± 0.3 L·min-1·m-1.83; postpartum, LOW = 2.3 ± 0.4 L·min-1·m-1.83, MOD = 3.0 ± 0.5 L·min-1·m-1.83; P = 0.96). Basal circumferential strain was higher in pregnant women at rest, during the sustained isometric forearm contraction (-23.5% ± 1.2%; nonpregnant, -14.6% ± 1.4%; P = 0.001), and during dynamic cycling exercise (LOW = -27.0% ± 4.9%, MOD = -27.4% ± 4.6%; nonpregnant, LOW = -15.8% ± 4.5%, MOD = -15.2% ± 6.7%; P = 0.012); however, other parameters of LV mechanics were not different between groups. CONCLUSION: The results support that the maternal heart can appropriately respond to additional cardiac demand and altered loading experienced during acute isometric and dynamic exercise, although subtle differences in responses to these challenges were observed. In addition, the LV mechanics that underpin global cardiac function are greater in pregnant women during exercise, leading to the speculation that the hormonal milieu of pregnancy influences regional deformation.

Cardiovascular risk prediction using physical performance measures in COPD: results from a multicentre observational study.

OBJECTIVES: Although cardiovascular disease (CVD) is a common comorbidity associated with chronic obstructive pulmonary disease (COPD), it is unknown how to improve prediction of cardiovascular (CV) risk in individuals with COPD. Traditional CV risk scores have been tested in different populations but not uniquely in COPD. The potential of alternative markers to improve CV risk prediction in individuals with COPD is unknown. We aimed to determine the predictive value of conventional CVD risk factors in COPD and to determine if additional markers improve prediction beyond conventional factors. DESIGN: Data from the Evaluation of the Role of Inflammation in Chronic Airways disease cohort, which enrolled 729 individuals with Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage II-IV COPD were used. Linked hospital episode statistics and survival data were prospectively collected for a median 4.6 years of follow-up. SETTING: Five UK centres interested in COPD. PARTICIPANTS: Population-based sample including 714 individuals with spirometry-defined COPD, smoked at least 10 pack years and who were clinically stable for >4 weeks. INTERVENTIONS: Baseline measurements included aortic pulse wave velocity (aPWV), carotid intima-media thickness (CIMT), C reactive protein (CRP), fibrinogen, spirometry and Body mass index, airflow Obstruction, Dyspnoea and Exercise capacity (BODE) Index, 6 min walk test (6MWT) and 4 m gait speed (4MGS) test. PRIMARY AND SECONDARY OUTCOME MEASURES: New occurrence (first event) of fatal or non-fatal hospitalised CVD, and all-cause and cause-specific mortality. RESULTS: Out of 714 participants, 192 (27%) had CV hospitalisation and 6 died due to CVD. The overall CV risk model C-statistic was 0.689 (95% CI 0.688 to 0.691). aPWV and CIMT neither had an association with study outcome nor improved model prediction. CRP, fibrinogen, GOLD stage, BODE Index, 4MGS and 6MWT were associated with the outcome, independently of conventional risk factors (p<0.05 for all). However, only 6MWT improved model discrimination (C=0.727, 95% CI 0.726 to 0.728). CONCLUSION: Poor physical performance defined by the 6MWT improves prediction of CV hospitalisation in individuals with COPD. TRIAL REGISTRATION NUMBER: ID 11101.

Role of Vascular Adaptation in Determining Systolic Blood Pressure in Young Adults.

Background Two individuals can have a similar pulse pressure (PP) but different levels of systolic blood pressure (SBP), although the underlying mechanisms have not been described. We hypothesized that, for a given level of PP, differences in SBP relate to peripheral vascular resistance (PVR); and we tested this hypothesis in a large cohort of healthy young adults. Methods and Results Demographic, biochemical, and hemodynamic data from 3103 subjects were available for the current analyses. In both men and women, for a given level of PP, higher SBP was associated with significantly higher body weight, body mass index, heart rate, and PVR (P<0.05 versus those with lower BP for all comparisons). Moreover, stratifying individuals by quartiles of PP and PVR revealed a stepwise increase in SBP from the lowest to highest quartile for each variable, with the highest SBP occurring in those in the highest quartile of both PP and PVR (P<0.001 for overall trend for both sexes). PVR was also increased with increasing tertile of minimum forearm vascular resistance, in both men (P=0.002) and women (P=0.03). Conclusions Increased PVR, mediated in part through altered resistance vessel structure, strongly associates with the elevation of SBP for a given level of PP in young adults. An impaired ability to adapt PVR appropriately to a given level of PP may be an important mechanism underlying elevated SBP in young adults.

May Measurement Month 2018: an analysis of blood pressure screening results from the UK and the Republic of Ireland.

Raised blood pressure (BP) was the biggest contributor to the global burden of disease in 2017, with lack of awareness and adequate control of BP identified as the main drivers of this disease burden. In 2017, an opportunistic BP screening and awareness campaign called May Measurement Month (MMM) in the UK and Republic of Ireland (RoI) highlighted that levels of undiagnosed hypertension and uncontrolled hypertension in the community screened were approximately 23% and 40%, respectively. MMM18 was undertaken to further the campaign's efforts to increase awareness and create an evidence base of population risk associated with high BP. MMM18 BP screenings were conducted in the community at places of worship, supermarkets, GP surgeries, workplaces, community pharmacies, gyms, and various other public places. A total of 5000 volunteers, aged 47.3 (±17.2) years, 60% female were screened. Of all 5000 individuals screened, 1716 (34.3%) were hypertensive, of which only 51.3% were aware of their condition, 42.8% on antihypertensive treatment, and only 51.5% of those on medication controlled to target BP of <140/90 mmHg. Furthermore, obese, overweight, and underweight participants all had significantly higher BP values compared to individuals with a healthy body mass index (BMI). The 2018 MMM campaign in the UK and the RoI confirmed approximately one in three adults were hypertensive, with more than half having uncontrolled BP. In addition, these findings show that people with low BMI are at risk of having high BP. Finally, with only one in two people aware of their high BP, awareness remains a significant public health concern.

Changes in Blood Pressure and Arterial Hemodynamics following Living Kidney Donation.

BACKGROUND AND OBJECTIVES: The Effect of a Reduction in GFR after Nephrectomy on Arterial Stiffness and Central Hemodynamics (EARNEST) study was a multicenter, prospective, controlled study designed to investigate the associations of an isolated reduction in kidney function on BP and arterial hemodynamics. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Prospective living kidney donors and healthy controls who fulfilled criteria for donation were recruited from centers with expertise in vascular research. Participants underwent office and ambulatory BP measurement, assessment of arterial stiffness, and biochemical tests at baseline and 12 months. RESULTS: A total of 469 participants were recruited, and 306 (168 donors and 138 controls) were followed up at 12 months. In the donor group, mean eGFR was 27 ml/min per 1.73 m2 lower than baseline at 12 months. Compared with baseline, at 12 months the mean within-group difference in ambulatory day systolic BP in donors was 0.1 mm Hg (95% confidence interval, -1.7 to 1.9) and 0.6 mm Hg (95% confidence interval, -0.7 to 2.0) in controls. The between-group difference was -0.5 mm Hg (95% confidence interval, -2.8 to 1.7; P=0.62). The mean within-group difference in pulse wave velocity in donors was 0.3 m/s (95% confidence interval, 0.1 to 0.4) and 0.2 m/s (95% confidence interval, -0.0 to 0.4) in controls. The between-group difference was 0.1 m/s (95% confidence interval, -0.2 to 0.3; P=0.49). CONCLUSIONS: Changes in ambulatory peripheral BP and pulse wave velocity in kidney donors at 12 months after nephrectomy were small and not different from controls. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: NCT01769924 (https://clinicaltrials.gov/ct2/show/NCT01769924).

Atenolol's Inferior Ability to Reduce Central vs Peripheral Blood Pressure Can Be Explained by the Combination of Its Heart Rate-Dependent and Heart Rate-Independent Effects.

OBJECTIVE: Whether the inferior ability of atenolol to reduce central (aortic) compared to peripheral (brachial) blood pressure (BP) is related to its heart rate (HR)-dependent or -independent effects, or their combination, remains unclear. To provide further mechanistic insight into this topic, we studied the acute effects of atenolol versus nebivolol and ivabradine on systolic blood pressure amplification (SBPA; peripheral systolic BP minus central systolic BP) in a model of sick sinus syndrome patients with a permanent dual-chamber cardiac pacemaker in a nonrandomized single-blind single-group clinical trial. METHODS: We determined hemodynamic indices noninvasively (Sphygmocor XCEL) before and at least 3 h after administration of oral atenolol 50 or 100 mg, nebivolol 5 mg, or ivabradine 5 or 7.5 mg during atrial pacing at a low (40 bpm), middle (60 bpm), and high (90 bpm) HR level in 25 participants (mean age 65.5 years, 12 men). RESULTS: At the low HR level, i.e., when the drugs could exert their HR-dependent and HR-independent effects on central BP, only atenolol produced a significant decrease in SBPA (mean change 0.74 ± 1.58 mmHg (95% CI, 0.09-1.40; P = 0.028)), indicating inferior central vs peripheral systolic BP change. However, we observed no significant change in SBPA with atenolol at the middle and high HR levels, i.e., when HR-dependent mechanisms had been eliminated by pacing. CONCLUSION: The findings of our trial with a mechanistic approach to the topic imply that the inferior ability of atenolol to reduce central vs peripheral BP can be explained by the combination of its heart rate-dependent and -independent effects. This trial is registered with NCT03245996.

Respiratory and Cardiovascular Outcomes in Survivors of Extremely Preterm Birth at 19 Years.

Rationale: Growth and development during adolescence may modify the respiratory and vascular differences seen among extremely preterm (EP) individuals in childhood and early adolescence.Objectives: To assess the trajectory of respiratory and cardiovascular outcomes during transition to adulthood in a national longitudinal cohort study of births before 26 weeks of gestation in the United Kingdom and Ireland.Methods: A total of 129 EP participants and 65 control subjects attended for a center-based evaluation at 19 years of age. Standardized measures of spirometry, hemodynamics, functional capacity, and markers of inflammation were obtained from EP subjects with and without neonatal bronchopulmonary dysplasia and term-born control subjects at 19 years of age and compared with previous assessments.Measurements and Main Results: Compared with the control group, the EP group was significantly impaired on all spirometric parameters (mean FEV1z-score, -1.08 SD [95% confidence interval, -1.40 to -0.77]) and had lower fractional exhaled nitric oxide concentrations (13.9 vs. 24.4 ppb; P < 0.001) despite a higher proportion with bronchodilator reversibility (27% vs. 6%). The EP group had significantly impaired exercise capacity. All respiratory parameters were worse after neonatal bronchopulmonary dysplasia, and respiratory function differences were similar at 11 and 19 years. The augmentation index was 6% higher in the EP group and associated with increased total peripheral resistance (difference in means, 96.4 [95% confidence interval, 26.6-166.2] dyne/s/cm-5) and elevation in central, but not peripheral, blood pressure. Central systolic and diastolic blood pressures increased more quickly during adolescence in the EP group than in the control group.Conclusions: Clinicians should address both cardiovascular and respiratory risks in adult survivors of extremely preterm birth.

Bionic women and men - Part 2: Arterial stiffness in heart failure patients implanted with left ventricular assist devices.

NEW FINDINGS: What is the topic of this review? This review discusses how implantation of continuous flow left ventricular assist devices impact arterial stiffness and outcome. What advances does it highlight? Not all patients implanted with continuous flow left ventricular assist devices show an increase in arterial stiffness. However, in those patients where arterial stiffness increases, levels of composite outcome (stroke, gastrointestinal bleeding, pump thrombosis and death) is significantly higher than those who's arterial stiffness does not increase. ABSTRACT: In parallel with the major advances in clinical care, technological advancements and implantation of mechanical circulatory support in patients with severe heart failure have resulted in these patients living longer. However, these patients are still at increased risk of stroke and gastrointestinal bleeding. The unique continuous flow produced by various left ventricular assist devices (LVADs) has been suggested as one potential reason for this increased risk of stroke and gastrointestinal bleeding. Furthermore, these continuous-flow (CF) devices challenge our understanding of circulatory blood pressure and flow regulation in relationship to organ health. In healthy pulsatile and dynamic systems, arterial stiffness is a major independent risk factor for stroke. However, to date, there are limited data regarding the impact of CF-LVAD therapy on arterial stiffness. The purpose of this report is to discuss the variable impact of CF-LVAD therapy on arterial stiffness and attempt to highlight some potential mechanisms linking these associations in this unique population.

Daily physical activity and related risk factors in COPD.

BACKGROUND: Factors associated with reduced daily physical activity (DPA) in patients with COPD are still controversial. Physical inactivity in COPD increases risk of cardiovascular disease, frequent exacerbations, reduced health status, and increased symptoms. We hypothesised that reduced DPA in patients with COPD is independent of traditional risk factors including age and spirometry. METHODS: In this cross-sectional study, DPA (over 7 days) was assessed on 88 community stable patients with COPD and 40 controls free from cardiorespiratory disease. Spirometry, body composition, number of exacerbations, handgrip strength (HGS), modified Medical Research Council (mMRC), arterial stiffness, 6-min walking distance (6MWD) and BODE index were also determined. Frequent exacerbation was defined as ≥2 and non-frequent exacerbation < 2. RESULTS: Patients with COPD had reduced DPA and exercise capacity compared with controls similar in age, BMI and gender, p < 0.001. Frequent exacerbators had less DPA than infrequent exacerbators and both less than controls, p < 0.001. Patients with higher BODE index were less active than those with lower index. Time spent on moderate activity was related to cardiovascular risk factors including arterial stiffness. The DPA in patients was independent of age, gender, spirometry, body composition and HGS, p > 0.05. The level of breathlessness was superior to lung function in predicting the level of DPA. CONCLUSION: The level of DPA in COPD was independent of traditional risk factors. Breathlessness score is a better predictor of the DPA than lung function and handgrip strength.

Bionic women and men - Part 1: Cardiovascular lessons from heart failure patients implanted with left ventricular assist devices.

NEW FINDINGS: What is the topic of this review? Patients with advanced heart failure who are implanted with left ventricular assist devices (LVADs) present an opportunity to understand the human circulation under extreme conditions. What advances does it highlight? LVAD patients have a unique circulation that is characterized by a reduced or even absent arterial pulse. The remarkable survival of these patients is accompanied by circulatory complications, including stroke, gastrointestinal bleeding and right-heart failure. Understanding the mechanisms related to the complications in LVAD patients will help the patients and also advance our fundamental understanding of the human circulation in general. ABSTRACT: Some humans with chronic, advanced heart failure are surgically implanted with a left ventricular assist device (LVAD). Because the LVAD produces a continuous flow, a palpable pulse is often absent in these patients. This allows for a unique investigation of the human circulation and has created a controversy around the 'need' for a pulse. The medical debate has also generated a more generic, fundamental discussion into what is 'normal' arterial physiology and health. The comprehensive study and understanding of the arterial responses to drastically altered haemodynamics due to continuous-flow LVADs, at rest and during activity, presents an opportunity to significantly increase our current understanding of the fundamental components of arterial regulation (flow, blood pressure, sympathetic activity, endothelial function, pulsatility) in a way that could never have been studied previously. In a series of four articles, we summarize the talks presented at the symposium entitled 'Bionic women and men - Physiology lessons from implantable cardiac devices' presented at the 2019 Annual Meeting of The Physiological Society in Aberdeen, UK. The articles highlight the novel questions generated by physiological phenomena observed in LVAD patients and propose future areas of interest within the field of cardiovascular physiology.

Bionic women and men - Part 4: Cardiovascular, cerebrovascular and exercise responses among patients supported with left ventricular assist devices.

NEW FINDINGS: LVAD patients are predisposed to hypertension which may increase the risk of stroke. Hypertension may result from markedly elevated levels of sympathetic nerve activity, which occurs through a baroreceptor-mediated pathway in response to chronic exposure to a non-physiologic (and reduced) pulse. Cerebral autoregulatory processes appear to be preserved in the absence of a physiologic pulse. Nevertheless, the rate of ischemic/embolic and hemorrhagic stroke is unacceptably high and is a major cause of morbidity and mortality in these patients. Despite normalization of a resting cardiac output, LVAD patients suffer from persistent, severe reductions in functional capacity. ABSTRACT: Current generation left ventricular assist devices (LVADs) have led to significant improvements in survival compared to medical therapy alone, when used for management of patients with advanced heart failure. However, there are a number of side-effects associated with LVAD use, including hypertension, gastrointestinal bleeding, stroke, as well as persistent and severe limitations in functional capacity despite normalization of a resting cardiac output. These issues are, in large part, related to chronic exposure to a non-physiologic pulse, which contributes to a hyperadrenergic environment characterized by markedly elevated levels of sympathetic nerve activity through a baroreceptor-mediated pathway. In addition, these machines are unable to participate in, or contribute to, normal cardiovascular/autonomic reflexes that attempt to modulate flow through the body. Efforts to advance device technology and develop biologically sensitive devices may resolve these issues, and lead to further improvements in quality-of-life, functional capacity, and ultimately, survival, for the patients they support.

Risk assessment for hospital admission in patients with COPD; a multi-centre UK prospective observational study.

In chronic obstructive pulmonary disease (COPD), acute exacerbation of COPD requiring hospital admission is associated with mortality and healthcare costs. The ERICA study assessed multiple clinical measures in people with COPD, including the short physical performance battery (SPPB), a simple test of physical function with 3 components (gait speed, balance and sit-to-stand). We tested the hypothesis that SPPB score would relate to risk of hospital admissions and length of hospital stay. Data were analysed from 714 of the total 729 participants (434 men and 280 women) with COPD. Data from this prospective observational longitudinal study were obtained from 4 secondary and 1 tertiary centres from England, Scotland, and Wales. The main outcome measures were to estimate the risk of hospitalisation with acute exacerbation of COPD (AECOPD and length of hospital stay derived from hospital episode statistics (HES). In total, 291 of 714 individuals experienced 762 hospitalised AECOPD during five-year follow up. Poorer performance of SPPB was associated with both higher rate (IRR 1.08 per 1 point decrease, 95% CI 1.01 to 1.14) and increased length of stay (IRR 1.18 per 1 point decrease, 95% CI 1.10 to 1.27) for hospitalised AECOPD. For the individual sit-to-stand component of the SPPB, the association was even stronger (IRR 1.14, 95% CI 1.02 to 1.26 for rate and IRR 1.32, 95% CI 1.16 to 1.49 for length of stay for hospitalised AECOPD). The SPPB, and in particular the sit-to-stand component can both evaluate the risk of H-AECOPD and length of hospital stay in COPD. The SPPB can aid in clinical decision making and when prioritising healthcare resources.

Bionic women and men - Part 3: Right ventricular dysfunction in patients implanted with left ventricular assist devices.

NEW FINDINGS: What is the topic of this review? Right heart dysfunction remains a major adverse event in patients with end stage heart failure undergoing left ventricular assist device placement. This article reviews the pathophysiology and clinical considerations of right heart failure in this patient population. What advances does it highlight? This review highlights the anatomic and physiological peculiarities of the interplay between left and right heart function in patients undergoing LVAD therapy. These would allow us to further advance our understanding of right ventricular function. ABSTRACT: The adaptation of the right ventricular (RV) output to a left ventricular assist device (LVAD) often determines the fate of patients with pulmonary hypertension secondary to left heart failure. Pre-existing right heart dysfunction in patients with advanced left heart failure is the consequence of increased (arterial) afterload and not simply the consequence of myocardial disease. If unaccounted for, it has the potential of accelerating into clinical right heart failure after LVAD, leading to significant morbidity and mortality. After LVAD implantation, the RV has to face increased flow generated by the LVAD, cardiac arrhythmias and exaggerated functional interactions between both ventricles. Understanding the key physiological mechanisms of RV dysfunction in patients with end-stage heart failure will allow us to predict and therefore prevent RV failure after LVAD implantation.