Lower Stroke Volume Research Articles

Abstract 4137186: No Room for Chronotropic Incompetence in Living Fontan Patients: Enhanced Heart Rate Increase in Response to Exercise to Compensate Low Stroke Volume Reserve

Background: Fontan patients reveal decreased peak exercise performance in combination with low peak heart rate (HR), which is frequently interpreted as chronological incompetence. This is counterproductive as HR increase has to be enhanced to compensate limited stroke volume increase in Fontan physiology. Methods: Cardiopulmonary exercise testing (CPET) data in asymptomatic Fontan patients and age-matched control subjects were retrospectively studied. Peak and submaximal CPET parameters were obtained by cycle ergometer. Chronotropic capacity was assessed by peak HR/peak [WR/kg] and submaximal slope of HR/[work rate (WR)/kg] (ΔHR/Δ[WR/kg]) for males and females, separately. Results: Table 1 presents CPET data of Fontan patients (51) and controls (65). Fontan patients showed significantly lower peak HR, peak WR, peak oxygen consumption (VO2)/kg, %predicted maximum VO2, and peak oxygen pulse (pOP)/kg than controls in both sexes whereas peak HR/peak [WR/kg] was significantly higher in Fontan patients, indicating higher HR at the maximum effort in Fontan patients than in controls. Fontan patients showed higher ΔHR/Δ[WR/kg], a marker for HR-dependency, and lower Δ[VO2/kg]/ΔHR, a surrogate of stroke volume, suggesting higher HR was compensating lower stroke volume during submaximal phase of exercise in Fontan patients. Figure 1 demonstrates a linear relationship between ΔHR/ΔWR and peak HR/peak WR in both sexes. Male Fontan patients revealed a comparable trend with controls, whereas female Fontan patients showed higher HR increase at the peak exercise effort than controls with the same ΔHR/ΔWR, suggesting more limited stroke volume reserve than male Fontan patients. Conclusions: Fontan patients showed higher HR-response to exercise than controls in both sexes due to limitation in stroke volume increase. Our data indicate that lower peak HR in Fontan patients results from early exhaustion due to limited stroke volume reserve rather than primary chronotropic incompetence.

Long term outcomes of patients with decompensated aortic stenosis undergoing urgent transcatheter aortic valve implantation: a TAVI-NOR subs-study

Abstract Background Aortic stenosis (AS) is a progressive disease, which untreated leads to irreversible myocardial damage and potentially death. Patients with AS may present with acute decompensation (ADAS) even during active surveillance. Purpose In this TAVI-NOR sub-study, we investigate the clinical profile, risk factors, epidemiology and long-term outcomes of patients treated with TAVI after presenting with ADAS compared to stable patients who underwent elective TAVI (no ADAS). Method A total of 600 patients with severe AS consecutively treated with TAVI between January 2012 and July 2019 were enrolled in TAVI-NOR study. Predictors and long-term clinical outcomes were explored in binary logistic and Cox regression models. Results A total of 68 patients (11.3%) received urgent TAVI due to acute hospitalization with ADAS. Age (80±8.0 years vs 81±6.0 years, p=0.662), gender (56% males vs 50% males, p=0.361) and other comorbidities at baseline such as cardiovascular disease, chronic lung disease and atrial fibrillation (AF) were comparable in patients with ADAS and no ADAS (n=532) (p>0.05 for all). However, patients with ADAS had greater symptom burden (NYHA III-IV 81% vs 51%, p<0.001), lower blood pressure, higher heart rate and lower estimated glomeruli filtration rate (52.0±10.8 vs 54.6±9.8 mL/min/1.73m2, p<0.045). They had also higher prevalence of ECG left ventricular (LV) hypertrophy (40% vs 27%, p=0.027), more often reduced LV ejection fraction (<50%) (41% vs 16%, p<0.001), lower stroke volume (39±11 ml/m2 vs 42±11 ml/m2 vs, p=0.030) a trend of abnormal ECG (p=0.055) and longer hospital stay (11.5 ±8.7 days 6.6± 4.9 days, p<0.001). Patients with ADAS were comparable with no ADAS in terms of early short-term (<30 days) all-cause mortality (p>0.05). Although 1-year mortality was comparable (1.5% in ADAS vs 2.1% in no ADAS, p>0.99), mid- to late-term mortality rates were significantly higher in patient with ADAS receiving urgent TAVI, with 3-, 5- and 7 years mortality of 22% vs 11%, p=0.008; 46% vs 29%, p=0.005; 53% vs 39%, p=0.033, respectively. In a Kaplan-Meier analysis, event-free survival was significantly reduced for patients with ADAS undergoing urgent TAVI compared with stable patients undergoing elective TAVI HR 1.63, 95% CI 1.15-2.31, p=0.006), confirmed by a multivariable-adjusted model (HR 1.54; 95% CI 1.05-2.25, p=0.026) independent of age, gender, AF, LV ejection fraction and time from diagnosis to TAVI (Fig). Conclusion Patients with AS presenting with acute decompensation and treated with urgent TAVI had excellent short-term survival. This was irrespective of increased symptom burden, adversely remodeled and functionally reduced LV at baseline. These findings might explain the observed higher mid- and long-term mortality compared with stable patients undergoing elective TAVI. It is essential to identify patients at risk of acute decompensation and treat them timely before irreversible myocardial damage occur.

Multi-modal characterisation of early-stage, subclinical cardiac deterioration in patients with type 2 diabetes.

Type 2 diabetes mellitus (T2DM) is a major risk factor for heart failure with preserved ejection fraction and cardiac arrhythmias. Precursors of these complications, such as diabetic cardiomyopathy, remain incompletely understood and underdiagnosed. Detection of early signs of cardiac deterioration in T2DM patients is critical for prevention. Our goal is to quantify T2DM-driven abnormalities in ECG and cardiac imaging biomarkers leading to cardiovascular disease. We quantified ECG and cardiac magnetic resonance imaging biomarkers in two matched cohorts of 1781 UK Biobank participants, with and without T2DM, and no diagnosed cardiovascular disease at the time of assessment. We performed a pair-matched cross-sectional study to compare cardiac biomarkers in both cohorts, and examined the association between T2DM and these biomarkers. We built multivariate multiple linear regression models sequentially adjusted for socio-demographic, lifestyle, and clinical covariates. Participants with T2DM had a higher resting heart rate (66 vs. 61 beats per minute, p < 0.001), longer QTc interval (424 vs. 420ms, p < 0.001), reduced T wave amplitude (0.33 vs. 0.37mV, p < 0.001), lower stroke volume (72 vs. 78ml, p < 0.001) and thicker left ventricular wall (6.1 vs. 5.9mm, p < 0.001) despite a decreased Sokolow-Lyon index (19.1 vs. 20.2mm, p < 0.001). T2DM was independently associated with higher heart rate (beta = 3.11, 95% CI = [2.11,4.10], p < 0.001), lower stroke volume (beta = -4.11, 95% CI = [-6.03, -2.19], p < 0.001) and higher left ventricular wall thickness (beta = 0.133, 95% CI = [0.081,0.186], p < 0.001). Trends were consistent in subgroups of different sex, age and body mass index. Fewer significant differences were observed in participants of non-white ethnic background. QRS duration and Sokolow-Lyon index showed a positive association with the development of cardiovascular disease in cohorts with and without T2DM, respectively. A higher left ventricular mass and wall thickness were associated with cardiovascular outcomes in both groups. T2DM prior to cardiovascular disease was linked with a higher heart rate, QTc prolongation, T wave amplitude reduction, as well as lower stroke volume and increased left ventricular wall thickness. Increased QRS duration and left ventricular wall thickness and mass were most strongly associated with future cardiovascular disease. Although subclinical, these changes may indicate the presence of autonomic dysfunction and diabetic cardiomyopathy.

The cardiac, vasomotor and myocardial branches of the baroreflex in hypotension: indications of reduced venous return to the heart.

Alterations of autonomic cardiovascular control are implicated in the origin of chronic low blood pressure (BP) (hypotension), but comprehensive analysis of baroreflex function is still lacking. This study explored baroreflex function in its cardiac, vascular and myocardial branches METHODS: Continuous BP was recorded at rest and during a mental arithmetic task in 40 hypotensive and 40 normotensive participants. Assessed cardiovascular variables included stroke volume (SV) (calculated by the Modelflow method), heart rate (HR), cardiac output (CO), total peripheral resistance (TPR) and heart rate variability (HRV). Baroreflex sensitivity (BRS) was calculated using the spontaneous sequence method. Hypotensive participants exhibited greater BRS in the three baroreflex branches, in addition to lower SV, HR and CO and higher HRV and TPR. Reactivity for BP, HRV and CO during the stress task was reduced in hypotensive individuals. The greater cardiac BRS can explain the lower HR and higher HRV observed in hypotension, suggestive of increased vagal cardiac influences. The higher vasomotor BRS may contribute to the greater TPR observed in the hypotensive participants. Abnormal associations between myocardial BRS and SV arose, suggesting aberrant autonomic control of myocardial contractility in hypotension. The results indicate that hemodynamic deficits in hypotension are related to preload factors, probably triggered by hypovolemia and reduced unstressed blood reserves, resulting in lower venous return, ventricular preload and SV. In contrast, afterload mechanisms seem to work appropriately.

Pelvic congestion syndrome analysis through quantitative 2-dimensional phase-contrast magnetic resonance imaging: A promising vision from an observational cohort study.

To examine the application of quantitative 2-dimensional phase-contrast magnetic resonance imaging (2D PC-MRI) for treating patients with pelvic congestion syndrome (PCS). We conducted a retrospective cross-sectional analysis by using quantitative 2D PC-MRI data enrolled between April 2017 and Sep 2023. In addition, 32 healthy female controls (HCs) were included. Most patients with PCS presented with chronic pelvic pain and more than half had extra-pelvic venous symptoms (80/81, 98% and 45/81, 56%, respectively). Quantitative 2D PC-MRI analyzed the 81 patients with PCS, 239 patients without PCS, and 32 HCs. The patients with PCS had higher stroke volume (SV), absolute SV (ASV), and mean flux (MF) in the calf region (interstitial pixel shift) than did the HCs. In the left gonadal vein, the patients with PCS had higher SV, backward flow volume (BFV), ASV, and MF and lower forward flow volume (FFV), stroke distance (SD), and mean velocity (MV) than did the HCs. However, the patients with PCS had lower SV, FFV, MF, SD, and MV in the great saphenous veins. Quantitative 2D PC-MRI analysis revealed that the PCS group had higher SV, FFV, BFV, ASV, and MF in the calf region than did the non-PCS group. The variables that most strongly differentiated the patients with PCS from the HCs were SV in the great saphenous veins, SD in the great saphenous veins and left gonadal vein, and MV in the great saphenous veins and left gonadal vein. Caudal flow in the left gonadal vein was identified in half of the patients with PCS (39/81, 48.1%); 14 of them received embolization for left gonadal vein. In additional to providing an objective 3-dimensional morphology of the pelvic veins and extra-pelvic leaks, quantitative 2D PC-MRI analysis reveals distinct hemodynamic profiles between patients with PCS, those without PCS, and HCs, especially in the gonadal veins and regional perfusion of the calves.

Correlation Analysis of Activity Levels and Risk Factors in Patients with Stroke: Variations in Cardiac Function According to the Longshi Scale.

This study examined the link between physical activity levels, as measured by the Longshi Scale, and cardiac function and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels in stroke patients, aiming to find correlations with stroke risk factors. The study involved 123 apoplexy patients divided into four groups based on the Longshi Scale: bedridden (31), domestic (32), community (30), and health (30). Clinical data was collected, and hemodynamic assessments were performed using impedance cardiography. Cardiac output time index (CTI) and estimated ejection fraction (EF est) were significantly reduced in both the domestic and community groups compared to the health group (P < 0.05), while diastolic arterial blood pressure (DABP) and systemic vascular resistance index (SVRi) were increased. In the bedridden group, stroke volume (SV), cardiac output (CO), CTI, left cardiac work index (LCWi), and EF est were all lower compared to the health group (P < 0.05), with SVRI and NT-proBNP levels being higher. Additionally, the bedridden group exhibited lower SV, CO, DABP, LCWi, CTI, and EF est when compared to the domestic and community groups (P < 0.05), but higher end-diastolic filling rate (EDFR) and NT-proBNP levels. The Longshi Scale grading positively correlated with SV (r = 0.536, P < 0.01), and NT-proBNP, EF, and cognitive dysfunction were found to be associated with activity levels in stroke patients. The Longshi Scale correlates with cardiac function indicators like NT-proBNP and EF, and can help identify stroke patients at risk of cardiac dysfunction. Moreover, cognitive dysfunction was identified as a significant factor influencing the range of activity in patients with stroke.

Sex-related disparities in aortic stenosis from disease awareness to treatment: a state-of-the-art review.

This state-of-the-art review aimed to synthesize evidence from various sex-stratified studies on aortic stenosis (AS), focusing on the difference in clinical presentation, anatomical characteristics, pathophysiology, and management of AS. In comparison to men, women with AS are present at later stages, are older, more symptomatic, frailer, and exhibit higher operative risk [Society of Thoracic Surgeons (STS) score]. Women tend to have smaller aortic valve (AV) areas and left ventricular (LV) outflow tract, leading to lower stroke volumes (SVs) than men and have a higher prevalence of paradoxical, low-flow, low-gradient AS. In women, chronic pressure overload due to AS results in concentric LV remodelling and hypertrophy, characterized by reduced LV cavities, higher filling pressures, lower wall stress, and more diastolic dysfunction. Conversely, men exhibit more dilated eccentric LV remodelling and hypertrophy. AVs in women are less calcified but more fibrotic. Moreover, women are often underdiagnosed, have severity underestimated, and experience delays or receive fewer referrals for AV replacement (AVR). However, women tend to benefit from transcatheter AVR (TAVR) with a long-term survival advantage over men, although the incidence of vascular complications and bleeding events in 30 days after TAVR is higher in women. Surgical AVR (SAVR) in women has high operative risk, is technically demanding and has poorer outcomes with increased mortality at 30 days compared to men. According to the STS score and EuroSCORE, the female sex itself is considered a risk factor for SAVR. Therefore, addressing sex-related disparities in AS and increasing awareness among physicians promises improved diagnosis and treatment, facilitating equitable care and the development of sex-specific personalized medicine.

Childhood family environment and systemic haemodynamics in adulthood: the Cardiovascular Risk in Young Finns Study.

Childhood family environment is associated with adulthood health behaviours and cardiovascular health, but limited data are available concerning the relationship between childhood family environment and adulthood haemodynamic determinants of blood pressure. We evaluated how childhood family environment predicts adulthood systemic haemodynamics. The sample came from the Cardiovascular Risk in Young Finns Study (n=1554-1620). Childhood family environment (1980) was assessed with four cumulative risk scores: socioeconomic family risk, risky emotional family atmosphere, stressful life events, and parents' risky health behaviours. Haemodynamic outcomes in 2007 (participants being 30-45 year-olds) included stroke volume index, systemic vascular resistance index, cardiac output index and heart rate. Analyses were adjusted for childhood (1980) cardiovascular risk factors (high-density lipoprotein and low-density lipoprotein cholesterol, triglycerides, insulin, body mass index and systolic blood pressure); and adulthood (2007) health behaviours (alcohol consumption, smoking, physical activity); and finally for adulthood cardiovascular risk factors. When adjusted for age and sex, high socioeconomic family risk predicted lower stroke volume index (P=0.001), higher heart rate (P=0.001) and higher systemic vascular resistance index (P=0.030). These associations remained after controlling for childhood cardiovascular covariates or adulthood health behaviours (P⩽0.02 for all) but diluted after controlling for adulthood cardiovascular risk factors. The other childhood cumulative risk scores (stressful life events, risky emotional atmosphere, or parents' risky health behaviour) did not predict adulthood haemodynamic outcomes. High childhood socioeconomic family risk predicted adulthood haemodynamic outcomes independently of childhood cardiovascular risk factors and adulthood health behaviours, while other childhood psychosocial adversities were not associated with cardiovascular function in adulthood.

Association Between Right Ventricular Systolic Parameters Measured by Echocardiography and Stroke Volume Derived From Pulmonary Artery Catheter in Ischemic Cardiogenic Shock

Objective: To determine the right ventricular (RV) systolic function echocardiographic parameter best associated with native stroke volume (SV) by thermodilution via pulmonary artery catheter (PAC) in patients admitted to intensive care with ST-elevation myocardial infarction (STEMI) complicated by cardiogenic shock (CS).Design, Setting, and Participants: Observational cohort study of 43 prospectively identified patients admitted to a tertiary cardiac intensive care unit in London, UK.Interventions: Simultaneous collection of comprehensive transthoracic echocardiographic, clinical, and PAC-derived hemodynamic data. Seven RV systolic function parameters were correlated with the PAC-derived SV.Measurements and Main Results: The median age was 61 [52, 67], and 36 patients (84%) were male. The median PAC-derived SV and LVEF were 57 ml [39, 70] and 31% [22, 35], respectively. The RV outflow tract velocity time integral (RVOT VTI) and tricuspid plane systolic excursion (TAPSE) correlated significantly with the PAC-derived SV (r = 0.42, p = 0.007, r = 0.37, p = 0.02, respectively). The RVOT VTI was independently associated with and predicted low PAC-derived SV (OR = 1.3, p = 0.03) with a good area under the curve (AUC = 0.71, p = 0.02). The RVOT VTI < 12.7 cm predicted low PAC-derived SV with a sensitivity of 66% and specificity of 72%.Conclusion: RVOT VTI is the echocardiographic RV systolic function parameter that best correlates with PAC-derived native SV in patients with STEMI complicated by CS. This parameter can help guide the hemodynamic management of this cohort.

Long-term stress exposure, cortisol level and cardiovascular activity and reactivity: Observations in patients with fibromyalgia.

Previous research suggested that exposure to long-lasting or repeated laboratory stressors may lead to rearrangement of cardiovascular control, with a shift of regulation mechanisms from dominant cardiac to dominant vascular influences between the early and late response phases, respectively. This study investigated whether similar rearrangement occurs during life stress accompanying chronic disease by analyzing also associations between cortisol level and cardiovascular variables in patients with fibromyalgia (FM). In 47 women with FM and 36 healthy women (HW), cardiovascular recordings were taken during active body posture changes (sitting, lying down, and standing). Moreover, hair cortisol concentration (HCC) was obtained. During standing, which involved orthostatic challenge, FM patients showed higher total peripheral resistance (TPR) but lower stroke volume (SV), cardiac output (CO), and baroreflex sensitivity than HW. During sitting and lying down, TPR was more closely associated with blood pressure (BP) than CO in FM patients; in contrast, CO was more closely associated with BP than TPR in HW. HCC correlated positively with TPR and BP in FM patients, but negatively with TPR and BP and positively with SV and CO in HW. Results suggest that chronic disease-related stress is associated with alterations in cardiovascular regulation toward greater involvement of vascular than cardiac mechanisms in BP control. Stress-related cortisol release may contribute to the long-term rearrangement of autonomic regulation. At the behavioral level, the dominance of vascular over cardiovascular control may relate to reduced somatic mobilization during an active fight-flight response in favor of passive and behaviorally immobile coping.

Low Stroke Volume Predicts Deterioration in Intermediate-Risk Pulmonary Embolism: Prospective Study.

Prognosis and management of patients with intermediate-risk pulmonary embolism (PE) is challenging. We investigated whether stroke volume may be used to identify the subset of this population at increased risk of clinical deterioration or PE-related death. Our secondary objective was to compare echocardiographic measurements of patients who received escalated interventions vs anticoagulation monotherapy. We selected patients with intermediate-risk PE, who had comprehensive echocardiography within 18 hours of PE diagnosis and before any escalated interventions, from a PE registry populated by 11 emergency departments. Echocardiographers measured right ventricle (RV) size, tricuspid annular plane systolic excursion (TAPSE), and stroke volume (SV) using velocity time integral (VTI) by left ventricular (LV) outflow tract Doppler or two-dimensional method of discs (MOD). The primary outcome was a composite of PE-related death, cardiac arrest, catecholamine administration for sustained hypotension, or emergency respiratory intervention during the index hospitalization. Secondary outcome was escalated intervention with reperfusion or extracorporeal membrane oxygenation therapy. Of 370 intermediate-risk PE patients (mean age 64.0 ± 15.5years, 38.1% male), 39 (10.5%) had the primary outcome. These 39 patients had lower mean SV regardless of measurement method than those without the primary outcome: SV MOD 36.2 vs 49.9 milliliters (mL), P < 0.001; SV Doppler 41.7 vs 57.2mL, P = 0.003; VTI 13.6 vs 17.9 centimeters [cm], P = 0.003. Patients with primary outcome also had lower mean TAPSE than those without (1.54 vs 1.81cm, P = 0.003). Multivariable models, selecting SV as predictor, had area under the receiver operating curve of 0.8 and Brier score 0.08. The best echocardiographic predictor of our primary outcome was SV MOD (odds ratio 0.72 [0.53, 0.94], P = 0.02). Patients who received escalated interventions had significantly lower SV or surrogate measurements, greater RV dilatation, and lower RV systolic function than patients who received anticoagulation monotherapy. Low stroke volume was a predictor of clinical deterioration and PE-related death. Low SV may be used to identify a subset of intermediate-risk PE patients, who are higher risk (intermediate-high risk), and for whom escalated interventions should be considered.

Subclinical vascular, hemodynamic and arterial stiffness changes in adults with cystic fibrosis: cross-sectional observational study

Cardiovascular diseases can be an emerging complication in cystic fibrosis (CF), as the median life expectancy has improved considerably. The objective of this study was to compare vascular, hemodynamic parameters and arterial stiffness in adult CF patients with healthy participants pared by sex and age, and to assess the factors associated with arterial stiffness in the CF group. This is a cross-sectional observational study. The evaluation of cardiovascular parameters was performed non-invasively using Mobil-O-Graph. 36 individuals with CF and 35 controls were evaluated. The mean arterial pressure (96.71 ± 10.98 versus 88.61 ± 7.40 mmHg, p = 0.0005), cardiac output (4.86 ± 0.57 versus 4.48 ± 0.44 L/min, p = 0.002) and systolic volume (64.30 ± 11.91 versus 49.02 ± 9.31 ml, p < 0.0001) were significantly lower in the CF group. The heart rate was higher in the CF when compared to the control (77.18 ± 10.47 versus 93.56 ± 14.57 bpm, p < 0.0001). The augmentation index (AIx@75) was higher in the CF than control (29.94 ± 9.37 versus 16.52 ± 7.179%, p < 0.0001). In the multivariate model controlled by body mass index and Forced Expiratory Volume in the first second, central systolic blood pressure and reflection coefficient directly related to AIx@75. Negatively related to AIx@75 were age and systolic volume. The adjusted determination coefficient was 87.40%. Individuals with CF presented lower arterial blood pressures and changes in cardiac function with lower stroke volume and cardiac output. The AIx@75, an indirect index of arterial stiffness and direct index of left ventricular overload, is increased in this population. The subclinical findings suggest the need for earlier cardiovascular assessment in this population due to increased risks of cardiovascular disease.

The Hemodynamic Changes Induced by Lung Recruitment Maneuver to Predict Fluid Responsiveness in Children during One Lung Ventilation-A Prospective Observational Study.

The prediction of fluid responsiveness in critical patients helps clinicians in decision making to avoid either under- or overloading of fluid. This study was designed to determine whether lung recruitment maneuver (LRM) would have an effect on the predictability of fluid responsiveness by the changes of hemodynamic parameters in pediatric patients who were receiving lung-protective ventilation and one-lung ventilation (OLV). A total of 34 children, aged 1-6 years old, scheduled for heart surgeries via right thoracotomy were enrolled. Patients were anesthetized and OLV with lung-protection ventilation settings was established, and then, positioned on left lateral decubitus. LRM and volume expansion (VE) were performed in sequence. Heart rate (HR), systolic arterial pressure (SAP), mean arterial pressure (MAP) diastolic arterial pressure (DAP), stroke volume (SV), stroke volume variation (SVV), and pulse pressure variation (PPV) were recorded via an A-line based monitor system at the following time points: before and after LRM (T1 and T2) and before and after VE (T3 and T4). An increase in stroke volume (SV) or mean arterial pressure (MAP) of ≥10% following fluid loading identified fluid responders. The predictability of fluid responsiveness by the changes of SV (ΔSVLRM) and MAP (ΔMAPLRM) after LRM and VE were statistically evaluated by receiver operating characteristic curves [area under the curves (AUC)]. SVs in all patients were significantly decreased after LRM (p < 0.01) and then, increased and returned to baseline after VE (p < 0.01). In total, 16 out of 34 patients who were fluid responders had significantly lower SV after LRM compared to that in fluid non-responders. The area under the receiver operating characteristic curves for ΔSVLRM was 0.828 (95% confidence interval [CI], 0.660 to 0.935; p < 0.001) and it indicated that ΔSVLRM was able to predict the fluid responsiveness of pediatric patients. MAPs in all patients were also decreased significantly after LRM, and 12 of them fell into the category of fluid responders after VE. Statistically, ΔMAPLRM did not predict fluid responsiveness when LRM was considered as an influential factor (p = 0.07). ΔSVLRM, but not ΔMAPLRM, showed great reliability in the prediction of the fluid responsiveness following VE in children during one-lung ventilation with lung-protective settings. ChiCTR2300070690.

The Flow Rate in Patients With Low-Gradient Aortic Stenosis.

The decision to assess the severity and determine the ideal timing of intervention for low-gradient aortic stenosis poses a greater challenge. Recently, a novel method for determining the flow status of patients with aortic stenosis has been introduced, utilizing flow rate measurements. In this study, we investigated whether the flow status of patients with low-gradient aortic stenosis is linked to mortality within a three-year timeframe. Twenty-nine patients diagnosed with low-gradient aortic stenosis and valve area ≤ 1 cmwere identified during 2010-2015. Each patient's flow rate across the aortic valve was computed, and the study scrutinized echocardiographic parameters to ascertain their correlation with mortality over a three-year timeframe. We observed that among patients with low-gradient aortic stenosis and a valve area of ≤1 cm, a decreased flow rate across the aortic valve emerged as an independent predictor of mortality. A flow rate < 210 ml/s was linked with a three-year mortality rate of 66.7%, whereas a low stroke volume index < 35 ml/m² did not show an association with three-year mortality. This observation might be attributed to the smaller body sizes prevalent among these older patients, particularly females, which could influence the calculation of the stroke volume index. In older patients with low-gradient aortic stenosis, the flow rate can better reflect flow status than the stroke volume index, and it also suggests a prognostic significance in predicting mortality. Additional studies are warranted to validate these findings across broader patient populations and to assess the potential efficacy of early intervention strategies in this particular patient cohort.

Elevated plasma solMER concentrations link ambient PM2.5 and PAHs to myocardial injury and reduced left ventricular systolic function in children

Exposure to fine particulate matter (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) is known to be associated with the polarization of pro-inflammatory macrophages and the development of various cardiovascular diseases. The pro-inflammatory polarization of resident cardiac macrophages (cMacs) enhances the cleavage of membrane-bound myeloid-epithelial-reproductive receptor tyrosine kinase (MerTK) and promotes the formation of soluble MerTK (solMER). This process influences the involvement of cMacs in cardiac repair, thus leading to an imbalance in cardiac homeostasis, myocardial injury, and reduced cardiac function. However, the relative impacts of PM2.5 and PAHs on human cMacs have yet to be elucidated. In this study, we aimed to investigate the effects of PM2.5 and PAH exposure on solMER in terms of myocardial injury and left ventricular (LV) systolic function in healthy children. A total of 258 children (aged three to six years) were recruited from Guiyu (an area exposed to e-waste) and Haojiang (a reference area). Mean daily PM2.5 concentration data were collected to calculate the individual chronic daily intake (CDI) of PM2.5. We determined concentrations of solMER and creatine kinase MB (CKMB) in plasma, and hydroxylated PAHs (OH-PAHs) in urine. LV systolic function was evaluated by stroke volume (SV). Higher CDI values and OH-PAH concentrations were detected in the exposed group. Plasma solMER and CKMB were higher in the exposed group and were associated with a reduced SV. Elevated CDI and 1-hydroxynaphthalene (1-OHNa) were associated with a higher solMER. Furthermore, increased solMER concentrations were associated with a lower SV and higher CKMB. CDI and 1-OHNa were positively associated with CKMB and mediated by solMER. In conclusion, exposure to PM2.5 and PAHs may lead to the pro-inflammatory polarization of cMacs and increase the risk of myocardial injury and systolic function impairment in children. Furthermore, the pro-inflammatory polarization of cMacs may mediate cardiotoxicity caused by PM2.5 and PAHs.

Blunted Exercise Pressor Reflex in Individuals with Down Syndrome

INTRODUCTION: Individuals with Down syndrome (DS) exhibit autonomic dysfunction, which contributes to reduced work capacity. The chemically sensitive component of the exercise pressor reflex, the metaboreflex, is responsible for exercise-induced sympathoexcitation and can be assessed via post-exercise muscle ischemia (PEMI). Blunted sympathoexcitation is common in individuals with DS and contributes to the physiological basis for reduced work capacity observed this population, but the influence of the metaboreflex is unknown. Using unilateral isometric knee extension exercise with PEMI, we hypothesized that individuals with DS would demonstrate a reduced metaboreflex compared to individuals without DS. METHODS: Twenty-four individuals with DS (M/F: 13/11; 24±5yrs; 30.3±6.2kg/m2) and without DS (M/F: 13/11; 25±4yrs; 26.5±4.5kg/m2) performed a unilateral isometric knee extension at 30% of their maximal voluntary contraction using their dominant leg on a leg dynamometer. Following 2-min of contraction, a thigh-cuff was rapidly inflated to 220 mmHg on the exercised leg for 3-min to isolate the activation of the muscle metaboreflex via PEMI. Beat-to-beat systolic blood pressure (SBP), stroke volume (SV), mean arterial pressure (MAP), and cardiac output (CO) were assessed using finger photoplethysmography coupled with Modelflow. Heart rate (HR) was collected via three-lead electrocardiogram. RESULTS: Despite similar baseline values of all variables in both groups, individuals with DS demonstrated a blunted pressor response to the isometric knee extension compared to individuals without DS (SBP; DS: 133±17 vs. Non-DS: 167±28 mmHg), and the blunted SBP response was maintained with PEMI (SBP; DS: 124±19 vs. Non-DS: 150±21 mmHg; time × group interaction, p&lt;0.001). Individuals with DS also exhibited a reduced HR 2-min into the contraction compared to those without DS (HR; DS: 90±16 vs. Non-DS: 114±22 bpm; timexgroup interaction, p&lt;0.001). Controlling for MVC, BMI, peak torque/body weight, and quadricep fat &amp; lean mass did not impact our results. Further, individuals with DS had a lower SV during the PEMI compared to individuals without DS (SV; DS: 93±24 vs. Non-DS: 113±23 mL/min; timexgroup interaction, p=0.003). CONCLUSION: Individuals with DS demonstrated a diminished metaboreflex response compared to their peers without DS, during a task known to induce sympathoexcitation, even when controlling for MVC. Our novel findings suggest that reduced influence of the metaboreflex contributes to the reduced exercise pressor response in persons with DS. Such exercise-specific peripheral autonomic perturbations contribute beyond our previous cardiac autonomic findings demonstrating blunted sympathoexcitatory perturbations in persons with DS, which likely contribute to reduced work capacity for this population. This research was funded in part by the American College of Sports Medicine Doctoral Research Award (#21-01558). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Abstract TP107: Quantifying Hospital Opportunities to Increase Thrombolysis

Introduction: Emergency-department-based implementation strategies to increase thrombolysis are promising. We sought to quantify the number of hospitals with opportunities to increase thrombolysis under various tPA treatment thresholds. Methods: We used data from the 2018 State Inpatient Databases (SID) from 17 states. The study population was limited to ischemic stroke patients admitted to the hospital. The primary outcome was the sum of patients receiving stroke thrombolysis (tPA) at each facility (DRG 61-63, ICD-10 procedure code 3E03317, ICD-10 diagnosis code Z92.82). The primary exposure was hospital stroke volume categorized into quartiles (1 st Quartile [Low]: 1-7, 2 nd Quartile: 8-53, 3 rd Quartile: 54-178, 4 th Quartile [High]: 179-1431). To estimate the number of additional patients treated if hospitals improve their thrombolysis rates across various thresholds, we calculated the expected number of thrombolysis treatments (tPA thresholds multiplied by hospital stroke volume and subtracted by the number of patients receiving tPA at each facility). Results: We identified 203,843 hospital admissions with a primary ischemic stroke diagnosis from 1608 hospitals. On average, 13.3% of patients received tPA. The proportion of stroke patients receiving tPA was higher in higher stroke volume hospitals (Table 1). Black people were more likely to receive care at high-stroke volume hospitals. Among 1608 hospitals, 1131 (70%) had tPA rates below 10%. If these 1131 hospitals improve their tPA rates to 10%, 2655 (2.3 patients/hospital/year) additional stroke patients would be treated with tPA. Conclusions: Low stroke volume hospitals have the lowest thrombolytic treatment rates, but interventions at these hospitals will have limited population benefits and may not be an efficient use of hospital resources. Intervening at high-volume, low-performing hospitals offers the largest opportunity to increase thrombolysis and will promote stroke racial equity.

Challenges in clinical identification of right ventricular dysfunction in preterm infants with persistent pulmonary hypertension of the newborn

BackgroundRight ventricular dysfunction, typically qualitatively diagnosed (Q-RVd) in preterm infants, requires echocardiography which is not always acutely available. We aimed to identify clinical indices of Q-RVd in very preterm infants (gestational age, GA <32 weeks) with persistent pulmonary hypertension of newborn (PPHN) and examine the reliability and validity of Q-RVd. MethodsForty-seven infants with mean ± SD GA of 26.8 ± 2.7 weeks who had targeted neonatal echocardiography (TNE) ≤72 h old, during PPHN, were retrospectively studied. Three standard TNE clips were reviewed by two blinded assessors, and infants categorized as Q-RVd if moderate-severe RVd was diagnosed on ≥2 clips. Cardiopulmonary clinical indices at TNE and quantitative RV functional markers were compared between Q-RVd vs. no-RVd groups. Potential quantitative RVd definitions examined by classifying each measurement as “low” or “normal” using published data. Inter-rater agreement for Q-RVd assessed using Kappa statistics. ResultsMean age at TNE was 25.3 ± 20.4 h with Q-RVd diagnosed in 19(40 %) infants. Q-RVd group demonstrated higher peak oxygen requirements (96 ± 9 % vs. 84 ± 16 %, p < 0.01); however, no clinical parameters at TNE differentiated the groups. Quantitative measures were lower in Q-RVd patients, confirming classification validity. Among tested quantitative definitions, low RV stroke volume was associated with lower systolic blood pressure (41±7 vs. 47±9 mmHg, p = 0.02) and higher shock index (4.02±0.80 vs. 3.44±0.72, p = 0.02). Kappa for Q-RVd was 0.55 (95%CI 0.32–0.77). ConclusionsThe non-specific nature of clinical markers of RVd in preterm infants with PPHN necessitates echocardiographic diagnosis of RVd. Studies should examine prognostic relevance of RVd and establish outcome-based quantitative definitions in preterm infants.

Microvascular Capillary and Precapillary Cardiovascular Disturbances Strongly Interact to Severely Affect Tissue Perfusion and Mitochondrial Function in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Evolving from the Post COVID-19 Syndrome.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a frequent, debilitating and still enigmatic disease. There is a broad overlap in the symptomatology of ME/CFS and the Post-COVID-19 Syndrome (PCS). A fraction of the PCS patients develop the full clinical picture of ME/CFS. New observations in microvessels and blood from patients suffering from PCS have appeared and include microclots and malformed pathological blood cells. Capillary blood flow is impaired not only by pathological blood components but also by prothrombotic changes in the vascular wall, endothelial dysfunction, and the expression of adhesion molecules in the capillaries. These disturbances can finally cause a low capillary flow and even capillary stasis. A low cardiac stroke volume due to hypovolemia and the inability of the capacitance vessels to adequately constrict to deliver the necessary cardiac preload generate an unfavorable low precapillary perfusion pressure. Furthermore, a predominance of vasoconstrictor over vasodilator influences exists, in which sympathetic hyperactivity and endothelial dysfunction play a strong role, causing the constriction of resistance vessels and of precapillary sphincters, which leads to a fall in capillary pressure behind the sphincters. The interaction of these two precapillary cardiovascular mechanisms causing a low capillary perfusion pressure is hemodynamically highly unfavorable in the presence of a primary capillary stasis, which is already caused by the pathological blood components and their interaction with the capillary wall, to severely impair organ perfusion. The detrimental coincidence of microcirculatory and precapillary cardiovascular disturbances may constitute the key disturbance of the Post-COVID-19 syndrome and finally lead to ME/CFS in predisposed patients because the interaction causes a particular kind of perfusion disturbance-capillary ischemia/reperfusion-which has a high potential of causing mitochondrial dysfunction by inducing sodium- and calcium-overload in skeletal muscles. The latter, in turn, worsens the vascular situation through the generation of reactive oxygen species to close a vicious cycle from which the patient can hardly escape.

Impact of homeostatic body hydration status, evaluated by hemodynamic measures, on different pain sensitization paths to a chronic pain syndrome

Contrasting findings on the mechanisms of chronic pain and hypertension development render the current conventional evidence of a negative relationship between blood pressure (BP) and pain severity insufficient for developing personalized treatments. In this interdisciplinary study, patients with fibromyalgia (FM) exhibiting clinically normal or elevated BP, alongside healthy participants were assessed. Different pain sensitization responses were evaluated using a dynamic 'slowly repeated evoked pain' (SREP) measure, as well as static pain pressure threshold and tolerance measures. Cardiovascular responses to clino-orthostatic (lying-standing) challenges were also examined as acute re- and de-hydration events, challenging cardiovascular and cerebrovascular homeostasis. These challenges involve compensating effects from various cardiac preload or afterload mechanisms associated with different homeostatic body hydration statuses. Additionally, hair cortisol concentration was considered as a factor with an impact on chronic hydration statuses. Pain windup (SREP) and lower pain threshold in FM patients were found to be related to BP rise during clinostatic (lying) rehydration or orthostatic (standing) dehydration events, respectively. These events were determined by acute systemic vasoconstriction (i.e., cardiac afterload response) overcompensating for clinostatic or orthostatic cardiac preload under-responses (low cardiac output or stroke volume). Lower pain tolerance was associated with tonic blood pressure reduction, determined by permanent hypovolemia (low stroke volume) decompensated by permanent systemic vasodilation. In conclusion, the body hydration status profiles assessed by (re)activity of systemic vascular resistance and effective blood volume-related measures can help predict the risk and intensity of different pain sensitization components in chronic pain syndrome, facilitating a more personalized management approach.