Systemic Blood Flow Research Articles

Функциональная активность эндотелия и иммунный статус при атеросклеротическом поражении аорто-подвздошного сегмента и реваскуляризации

Objective. The aim of the study is the evaluation of endothelial functional activity and immune status in systemic and local blood flow in atherosclerotic lesions of the aorto-iliac segment after open and endovascular interventions and establishing the relationship with the lesion class. Materials and methods. The study included 190 patients with lesions of the aorto-iliac segment. Depending on the type of surgical intervention, patients were divided into two groups: group I (n=97) - patients who underwent aorto-femoral bypass surgery, group II (n=93) - patients who underwent TRANS-balloon angioplasty with stenting of the iliac arteries. Results. Violations of the functional state of the endothelium and the immune status in the systemic and local blood flow, which do not correlate with the TASC II lesion class (TransAtlantic Inter-Society Consensus II), were revealed. There were differences in the factors of endothelial damage (in patients of group II before surgery, the level of homocysteine in the systemic blood flow, oxidized low-density lipoproteins in the systemic and local blood flow), hemostatic form of endothelial dysfunction (in group I, inhibitor of tissue plasminogen activator type I (PAI-1) in the systemic and tissue plasminogen activator (t-PA) in the local blood flow) and apoptosis (higher in group I in the systemic and local blood flow). During revascularization of the aorto-iliac segment, there were violations of the hemostatic form of endothelial dysfunction in group II with an increase in PAI-1 by 14.8% (p<0.001) in the systemic blood flow and by 1.9 times (p<0.001) in the revascularized arterial segment compared to group I. In group II after revascularization was significantly higher the immunoglobulins (Ig) class A in system and the circulating immune complexes, interleukins 1 (IL-1) in local blood flow and lower levels of IgM, interleukins 6 (IL-6), IL-1 in system and IgA, IgM, IL-6 in local blood flow compared with I group. Conclusion. The study of the features of the functional state of the endothelium and the immune status will optimize the management strategies of patients after various types of revascularization interventions on the aorto-iliac segment.

Endothelial dysfunction in patients with obliterating atherosclerosis of lower limb arteries in systemic and local blood flow

Background and Aims: Objective: to assess the state of endothelial dysfunction in patients with obliterating atherosclerosis with occlusive-stenotic lesion of the femoral-popliteal arterial segment and features in the systemic and local blood flow.

Sedentary Lifestyle: Overview of Updated Evidence of Potential Health Risks.

One-third of the global population aged 15 years and older engages in insufficient physical activities, which affects health. However, the health risks posed by sedentary behaviors are not well known. The mean daily duration of sedentary behavior is 8.3 hours among the Korean population and 7.7 hours among the American adult population. Sedentary lifestyles are spreading worldwide because of a lack of available spaces for exercise, increased occupational sedentary behaviors such as office work, and the increased penetration of television and video devices. Consequently, the associated health problems are on the rise. A sedentary lifestyle affects the human body through various mechanisms. Sedentary behaviors reduce lipoprotein lipase activity, muscle glucose, protein transporter activities, impair lipid metabolism, and diminish carbohydrate metabolism. Furthermore, it decreases cardiac output and systemic blood flow while activating the sympathetic nervous system, ultimately reducing insulin sensitivity and vascular function. It also alters the insulin-like growth factor axis and the circulation levels of sex hormones, which elevates the incidence of hormone-related cancers. Increased sedentary time impairs the gravitostat, the body’s weight homeostat, and weight gain, adiposity, and elevated chronic inflammation caused by sedentary behavior are risk factors for cancer. Sedentary behaviors have wide-ranging adverse impacts on the human body including increased all-cause mortality, cardiovascular disease mortality, cancer risk, and risks of metabolic disorders such as diabetes mellitus, hypertension, and dyslipidemia; musculoskeletal disorders such as arthralgia and osteoporosis; depression; and, cognitive impairment. Therefore, reducing sedentary behaviors and increasing physical activity are both important to promote public health.

Abstract 14860: Echocardiographic Assessment of Shunt Fraction in Complex Cyanotic Heart Diseases Palliated With Aortopulmonary Shunts

Introduction: Neonates with complex heart defects with inadequate pulmonary blood flow require aortopulmonary shunts (APS) either as surgical-placed modified Blalock-Taussig shunt or a catheter-based stent implantation into a patent ductus arteriosus. An ideal APS provides equal pulmonary blood flow (Qp) as the systemic blood flow (Qs), which is considered balanced circulation. Pulmonary over-circulation leads to complications from inadequate systemic circulation, such as organ dysfunction, shock, and death. Accurately determining Qp:Qs ratio in these patients relies on catheterization, which is invasive and may falsely lower the Qp due to anesthetic effects. To our knowledge, there has not been any studies on echocardiographic comparisons of balanced versus overcirculated APS. We aim to evaluate echocardiographic Doppler assessment of velocity-time integral (VTI) at the aortic arch isthmus distal to APS origin as a measure of shunt fraction in APS patients. We defined shunt fraction ratio (SFR) as retrograde to prograde flow by VTI. Methods: This is a retrospective pilot study of neonates with APS. We selected two cohorts of patients with appropriately balanced circulation (n=12) and those with excessive Qp (n=5) resulting in end-organ damage. We analyzed serial echocardiograms, with repeated measurements for inter-observer agreement. Results: Mean SFR is lower in balanced cohort compared to the overcirculated cohort (0.45 ± 0.07 vs. 0.55 ± 0.09, p=0.02). For both groups, SFR was positively associated with oxygen saturation (r= 0.57, p=0.01), as well as markers of ventricular volume load, such as the highest brain naturetic peptide during hospitalization (Pearson’s correlation r=0.83, p= 0.04) and as outpatient (r= 0.72, p =0.02). Inter-observer agreement was 0.74, suggesting that this is a reproducible technique. Conclusions: SFR by VTI is a simple echocardiographic technique to estimate the volume of APS flow and appears to have important implications for clinical outcomes. Prompt characterization of pulmonary overcirculation without invasive assessment could improve clinical management. Further prospective studies are needed to validate these findings.

Abstract 15805: Longitudinal Changes in Univentricular Patients Pre-Bidirectional Cavopulmonary Connection and Pre-Fontan

Background: Little is known about serial changes in the physiology of single ventricle (SV) patients during staged palliation and if HLHS patients differ from the rest. Methods: We analyzed SV patients who had a combined cath with CMR at both the preBCPC and preFontan studies from 2016-2019. Flow contrast mapping used to calculate pulmonary arterial (Qpa) and venous (Qpv) flow. Systemic blood flow (Qs) calculated using [superior vena cava (SVC) flow + descending aortic flow at the level diaphragm]. Cerebral vascular resistance (CVRi) calculated using [ascending aortic pressure (AoP)-right atrial pressure (RAP)/SVC flow]. Systemic vascular resistance (SVR) calculated using [(AoP-RaP)/Qs]. Pulmonary vascular resistance (PVR) was calculated using [(mean PAP - LAP)/Qpv]. Results: 30 patients were found, 10 with HLHS. The BCPC unloaded the heart, EDVi fell from preBCPC to preFontan. From preBCPC to preFontan(Table1): PA flow fell, but was compensated by increased APC flow to keep QpQs~1, PApressure and PVRi fell. Compared to others, the HLHS patients had larger hearts (EDVi) and lower PA but higher APC flow at both preBCPC(Table2)and preFontan(Table3). By preFontan, HLHS patients had worse function: higher ESVi, lower EF. Conclusion: QpQs ~1 is maintained by increase in APC flow. HLHS hearts are larger and deteriorate progressively.

Abstract 15302: Cardiac MRI Assessment of Cardiac Output Agrees With Simultaneous Fick Assessment in Pediatric Heart Transplant Patients

Introduction: Systemic cardiac output (Qs) and pulmonary blood flow (Qp) can be measured by cardiac magnetic resonance (CMR) and invasive oximetry, with studies showing good agreement between the two modalities. CMR-guided right heart catheterization (MR-RHC) collects simultaneous CMR and oximetry measurements permitting direct comparison. This study assessed agreement between CMR and Fick measurements of cardiac output in the pediatric heart transplant (HT) population. Methods: Twenty-three pediatric HT patients (body surface area range 0.6-2 m 2 ) with 53 MR-RHC between 2014 -2020 were reviewed. One outlier was excluded due to erroneous pulmonary vein saturation, leaving 52 MR-RHC for analysis. Measurements of un-indexed Qs and Qp from both CMR phase contrast and invasive oximetry using Fick were collected. Bland-Altman (BA) statistical and graphical analyses compared CMR versus Fick estimates of Qs and Qp. Results: BA limits of agreement (LOA) and corresponding concordance plot demonstrate good agreement between CMR and Fick (Figure 1). Panels A and B are the BA and concordance plots for Qs, respectively. Panels C and D are the BA and concordance plots for Qp, respectively. The 95% confidence interval LOA are -1.0 to +1.8 for Qs and -1.0 to +1.7 for Qp. Average bias and Lin correlation are similar for Qs and Qp at +0.36 L/min and 0.8, respectively. Conclusions: CMR and Fick measurements of Qs and Qp are similar in pediatric HT patients, with a tendency for slightly higher values by Fick estimates and similar LOA to previously published results. CMR acquired hemodynamics offer a radiation-free modality to reduce overall radiation exposure for pediatric HT patients.

Anomalous systemic arterial supply to the basal segment of the lung with giant aberrant artery: a case report

BackgroundAnomalous systemic arterial supply to the basal segment of the lung (ABLL) is a relatively rare congenital anomaly characterized by aberrant systemic arterial blood flow to the basal segment of the lung. We experienced a rare presentation of ABLL, in which a giant aberrant artery with the same dimensions as that of the descending aorta flowed from the celiac artery to left lower lobe.Case presentationAn otherwise healthy 42-year-old man was referred to our department due to an abnormal chest X-ray. Enhanced computed tomography revealed a huge and winding aberrant artery with mural thrombus originating from the celiac artery and perfusing into the left lower lobe. We diagnosed giant ABLL and considered possible concomitant pulmonary arteriovenous fistula. The diameter of the aberrant artery was > 30 mm and high-pressure flow was assumed; therefore, we performed staged resection of the left lower lobectomy including division of the aberrant artery at the pulmonary ligament and subsequent embolization of the remnant arterial flow uneventfully. Pathologically, the aberrant artery was abundant with elastic fibers, and dissections of the tunica media and mural thrombus were observed; however, arteriovenous fistula was not confirmed. At 6 postoperative months, enhanced computed tomography showed the aberrant artery to be completely occluded without any symptoms.ConclusionsWe present a case of ABLL that was successfully managed by surgical resection of the left lower lobe with most of the giant aberrant artery and subsequent embolization of the remnant portion. Our study demonstrates that a staged surgical therapy is an acceptable approach for ABLL in case of complication with a giant aberrant artery.

Acute hemodynamic effects of iatrogenic inter-atrial shunts after percutaneous edge-to-edge mitral valve repair

Abstract Background Implantable interatrial shunt devices improve pulmonary vascular function in patients with heart failure by transferring richly oxygenated blood to the right heart. Whether iatrogenic atrial septum defects (iASDs) after percutaneous edge-to-edge mitral valve repair (pMVR) are also associated with beneficial hemodynamic effects has not been investigated. Methods We consecutively enrolled patients with relevant functional (FMR) and degenerative mitral regurgitation (DMR) scheduled for pMVR. Invasive hemodynamic assessments were performed prior to and immediately after the procedure. Results 97 consecutive patients (75.4±9.1 years; 58% female) were prospectively included, 65 (66%) presented with relevant FMR. At baseline when compared to the DMR group, FMR was associated with worse left ventricular (LV) function (LV ejection fraction: 39 vs. 49%; p=0.001), higher NT-proBNP levels (7404 vs. 5214 pg/mL; p=0.023), worse renal function (serum creatinine: 1.7 vs. 1.3 mg/dL; p=0.019), and higher usage of spironolactone (68 vs. 42%; p=0.018) and sacubitril/valsartan (33 vs. 0%; p<0.001). Following pMVR, cardiac output (CO) and systemic blood flow (Qs) increased significantly (CO: 4.6 to 5.5 L/min; p<0.001; Qs: 4.9 to 5.8 L/min; p=0.002), with more pronounced changes in the FMR subgroup (ΔCO: 1.0 vs. 0.6 L/min; Figure 1A; ΔQs: 1.2 vs. 0.1 L/min), when compared to DMR. Pulmonary blood flow (Qp) increased by 26% (4.3 to 5.4 L/min; p=0.008), accompanied by a raise in pulmonary artery (PA) oxygen (O2) saturation from 73 to 77% (p<0.001). Arterial O2 saturation levels remained unchanged (98.3 to 98.7%; p=0.165), confirming no significant changes in systemic oxygenation. These changes were associated with a slight decline in pulmonary vascular resistance (PVR: 250 to 225 dynes*sec/cm5; p=0.369, Figure 1B), and a tendency towards improvement of pulmonary compliance (PAC: 3.6 to 4.0 mL/mmHg; p=0.414). Conclusions Invasively measured CO, Qs, Qp, and mixed-venous PA O2 saturation increased immediately after pMVR, alongside with potentially beneficial effects on pulmonary vasculature with marked improvements in PVR and PAC. These changes were more pronounced in the FMR subgroup. Further studies are required to assess long-term hemodynamic effects and underlying mechanisms of persistent iASDs on pulmonary vascular function. Figure 1. Invasive hemodynamics Funding Acknowledgement Type of funding source: None

T1 mapping to assess hepatic and myocardial characteristics in children with single ventricle circulation

Abstract Background Single ventricle (SV) palliation, culminating with the Fontan operation, results in passive systemic venous blood flow directly to the pulmonary circulation. Resulting inevitable hepatic venous congestion can lead to hepatic fibrosis. Previous studies suggest hepatic changes can occur prior to the Fontan completion. Besides fibrotic myocardial remodeling may lead to systolic and diastolic ventricular dysfunction, transmitting back pressure to the pulmonary system. Purpose To compare quantitative T1 cardiovascular magnetic resonance (CMR) imaging of the myocardium and liver between SV patients and controls, as a potential measure of myocardial and hepatic fibrosis. Methods Retrospective review of 16 SV patients with dominant single left ventricle (SLV, n=6) or single right ventricle (SRV, n=10), at various stages of palliation (pre-Glenn=6, post-Glenn=3, Fontan=7) underwent CMR with myocardial T1 mapping with the liver also in the plane of view. Biventricular patients found to have structurally normal hearts and normal cardiac function on CMR were used as controls (n=21). Native T1 times using a modified Look-Locker inversion recovery (MOLLI) approach in free-wall of the dominant ventricle at a mid-ventricular short axis in SV and the ventricular septum in controls and, a region of interest in the liver (avoiding any vessels) were measured in all patients. Median and inter-quartile ranges of continuous variables were compared between SV and controls using the Mann-Whitney U test. Results As compared to controls SV patients were (1) significantly younger, (2) had lower ejection fraction, (3) higher median myocardial T1, and (4) higher median liver T1. Also, there was no difference between SLV vs. SRV median myocardial T1 (1056 vs. 1065ms, p=0.43) or liver T1 (678 vs. 729ms, p=0.30) Conclusion Despite younger age, findings of increased myocardial T1 may suggest an element of myocardial fibrosis responsible for the ventricular dysfunction in this population, and that raised liver T1 may be an earlier marker of liver fibrosis, which warrants further study. Funding Acknowledgement Type of funding source: None

Plasma NT-proBNP and pulmonary to systemic blood flow ratio in congenital heart defects with left-to-right shunts

Background Cardiac left-to-right shunts changes to the pulmonary-to-systemic blood flow ratio (Qp/Qs ratio). This ratio can be used to monitor the hemodynamics of the heart. Left-to right-shunts cause the release of amino terminal proB-ty natriuretic peptide (NT-proBNP) that can be utilized as a specific marker for the presence of heart failure in children with congenital heart defects (CHDs). Early intervention such as defect closure in CHD is important to prevent heart failure. 
 Objective To assess for a correlation between the level of NT pro-BNP and Qp/Qs ratio in CHD patients with left-to-right shunts.
 Methods This cross-sectional, analytical study was conducted in 32 children who underwent cardiac catheterization at Sanglah General Hospital, Denpasar, Bali, and were recruited by consecutive sampling. NT-proBNP levels were measured by ELISA with a two-step sandwich assay system; Qp/Qs ratio using Fick rules. Statistical analyses included Shapiro-Wilk test, descriptive analysis for subject characteristics, and Pearson’s correlation analysis. A P value of <0.05 was considered to be statistically significant. Age and defect size were analyzed as confounding factors by partial correlation test.
 Results The correlation value between NT-proBNP and Qp/Qs ratio was r=0.384 (P<0.05), after controlling for age and defect size as cofounding factors.
 Conclusion There is a weak positive correlation between NT-proBNP levels and pulmonary-to-systemic blood flow ratio in patients with left-to-right shunt, after controlling for age and defect size as confounding factors.

Headache and Left Ventricular Efficiency After Transcatheter Closure of Atrial Septal Defect.

This study aimed to clarify the relationship between migraine-like headache and ventriculo-arterial coupling after transcatheter closure of the atrial septal defect in children. We hypothesized that migraine headache after defect closure would be related to an abnormal hemodynamic response against an increased left ventricular filling. A retrospective cohort study. We calculated the end-ventricular systolic elastance (Ees), effective arterial elastance (Ea), and ventricular energy efficiency approximated based on echocardiography before and after defect closure, and compared these parameters between the subjects with and without headache after defect closure. A total of 167 subjects were studied. Age at the procedure, defect diameter, and pulmonary to systemic blood flow ratio were 11 (9-17) years, 12.8 (9.2-16.0) mm, and 1.8 (1.6-2.3), respectively. We identified 47 (28%) subjects with migraine headache after defect closure. Although there was no significant difference in the Ees, Ea, and ventricular energy efficiency before defect closure between the groups, the Ees (4.0 [3.4-4.9] vs 4.8 [3.7-6.1], P=.014) and ventricular energy efficiency (0.79 [0.76-0.82] vs 0.83 [0.79-0.85], P=.001) after defect closure in subjects with headache were significantly lower than those in subjects without headache. Migraine headache after defect closure was significantly associated with age (odds ratio: 0.97, 95% confidential interval: 0.94-1.00, P=.036) and a decrease in the ventricular energy efficiency after defect closure (odds ratio: 6.42, 95% confidential interval: 2.76-14.90, P<.001). A loss of ventricular energy efficiency was common in pediatric subjects with migraine-like headache after transcatheter closure of the atrial septal defect, which suggested that the left ventricular function maladaptation was related to headache development after defect closure. We advocate that an impaired ventriculo-arterial coupling may be one of the mechanisms for developing attacks in not only this population but also in other patients with migraine.

The Relationship Between Preoperative Feeding Exposures and Postoperative Outcomes in Infants With Congenital Heart Disease.

To evaluate the association of preoperative risk factors and postoperative outcomes in infants with complex congenital heart disease. Single-center retrospective cohort study. Neonatal ICU and cardiovascular ICU. Infants of all gestational ages, born at Texas Children's Hospital between 2010 and 2016, with complex congenital heart disease requiring intervention prior to discharge. None. A total of 399 patients were enrolled in the study. Preoperative risk factors included feeding, type of feeding, feeding route, and cardiac lesion. Postoperative outcomes included necrotizing enterocolitis, hospital length of stay, and days to full feeds. The occurrence rate of postoperative necrotizing enterocolitis (all stages) was 8%. Preoperative feeding, type of feeding, feeding route, and cardiac lesion were not associated with higher odds of postoperative necrotizing enterocolitis. Cardiac lesions with ductal-dependent systemic blood flow were associated with a hospital length of stay of 19.6 days longer than those with ductal-dependent pulmonary blood flow (p < 0.001) and 2.9 days longer to reach full feeds than those with ductal-dependent pulmonary blood flow (p < 0.001), after controlling for prematurity. Nasogastric feeding route preoperatively was associated with a length of stay of 29.8 days longer than those fed by mouth (p < 0.001) and 2.4 days longer to achieve full feeds (p < 0.001), after controlling for prematurity and cardiac lesion. Preoperative diet itself was not associated with significant change in length of stay or days to reach full feeds. Although cardiac lesions with ductal-dependent systemic blood flow are considered high risk and may increase length of stay and days to achieve full feeds, they are not associated with a higher risk of postoperative necrotizing enterocolitis. Nasogastric route is not associated with a significantly higher risk of necrotizing enterocolitis, but longer length of stay and days to reach full feeds. These findings challenge our perioperative management strategies in caring for these infants, as they may incur more hospital costs and resources without significant medical benefit.

MATHEMATICAL MODELLING OF IMMUNE PROCESSES AND ITS APPLICATION

The aim of the study was to develop a mathematical model to research hypoxic states in case of simulation of an organism infectious lesions. The model is based on the methods of mathematical modeling and the theory of optimal control of moving objects. The processes of organism damage are simulated with the mathematical model of immune response developed by G.I. Marchuk and the members of his scientific school, adapted to current conditions. This model is based on Burnet’s clone selection theory of the determining role of antigen. Simulation results using the model are presented. The dependencies of infectious courses on the volumetric velocity of systemic blood flow is analyzed on the complex mathematical model of immune response, respiratory and blood circulation systems. The immune system is shown to be rather sensitive to the changes in blood flow via capillaries. Thus, the organ blood flows can be used as parameters for the model by which the respiratory, immune response, and blood circulation systems interact and interplay.

Systemic-to-Pulmonary Collateral Flow Correlates with Clinical Condition Late After the Fontan Procedure.

In the Fontan circulation, there is a substantial degree of systemic-to-pulmonary collateral flow (SPCF), which can be measured by cardiac magnetic resonance (CMR). However, the correlation between the degree of SPCF and long-term outcomes is not fully understood. We retrospectively studied 321 patients who underwent the Fontan procedure and CMR at a single center. Using CMR, we calculated SPCF as pulmonary blood flow - systemic blood flow. %SPCF was defined as SPCF ÷ pulmonary blood flow. The mean age of patients at CMR was 14.3 ± 7.5years. The average %SPCF was 13.0% ± 11.0%. With a multivariate analysis, %SPCF was significantly correlated with time (i.e., the longer the time period since the Fontan procedure, the lower the %SPCF) (p = 0.006), previous total anomalous pulmonary vein drainage (p = 0.007), a low pulmonary artery index (Nakata index) before the Fontan procedure (p = 0.04), and older age at the time of the Fontan procedure (p = 0.002). Regarding the findings after the Fontan procedure, %SPCF was significantly correlated with ventricular end-diastolic volume (p < 0.001), ventricular end-systolic volume (p < 0.001), central venous pressure (p < 0.001), plasma brain natriuretic peptide concentration (p < 0.001), hemoptysis (p = 0.009), and poor New York Heart Association functional class (p = 0.007). SPCF was correlated with clinical condition after the Fontan procedure. The importance of sufficient growth of the pulmonary vascular bed should be emphasized because the development of SPCF is believed to result from the poor condition of the pulmonary circulation.

Contribution of systemic blood flow to untreated or inadequately controlled systolic--diastolic or isolated systolic hypertension in a community sample of African ancestry.

Age-related increases in systemic blood flow [stroke volume (SV), cardiac output (CO), and aortic flow (Q)] contribute substantially to untreated or inadequately controlled (uncontrolled) blood pressure (BP) in Africa. We aimed to identify the haemodynamic determinants of uncontrolled systolic--diastolic (Syst--diast HT) versus uncontrolled isolated systolic (ISH) or diastolic (IDH) hypertension. Using central arterial pressure and aortic outflow tract velocity and diameter measurements (echocardiography), the haemodynamic correlates of BP were determined in 725 community participants of African ancestry (19.6% uncontrolled Syst--diast HT, 9.2% uncontrolled ISH, 11.3% uncontrolled IDH). Independent of confounders, compared with those with a normotensive BP, those with uncontrolled Syst--diast HT had increases in SV, CO, Q, systemic vascular resistance (SVR) and aortic characteristic impedance (Zc) and decreases in total arterial compliance (TAC) (P < 0.05--P < 0.0001). In multivariate regression models, uncontrolled Syst--diast HT was as strongly associated with Q, SV or CO as with SVR (P = 0.04--P = 0.20), Zc (P = 0.74--P < 0.0005) and TAC (P = 0.43--P < 0.005). Independent of confounders, compared with normotensive individuals those with uncontrolled ISH had increases in SV, CO, Q and Zc but not SVR, and decreases in TAC (P < 0.05-P < 0.0001), and those with IDH only had increases in SVR (P < 0.0001). Uncontrolled ISH was more strongly associated with Q, SV and CO than with SVR (P < 0.0005), but less than with TAC (P < 0.05--P < 0.0005). In groups of African ancestry living in Africa, hypertension because of increases in either SBP or DBP is as strongly associated with increases in systemic flow (SV, Q) as with arterial and arteriolar effects (Zc, TAC, SVR).

Bond Graph Model of Cerebral Circulation: Toward Clinically Feasible Systemic Blood Flow Simulations

The primary paper Safaei et al. (2018) proposed an anatomically detailed model of the human cerebral circulation that runs faster than real-time on a desktop computer and is designed for use in clinical settings when the speed of response is important. Based on a one-dimensional formulation of the flow of an incompressible fluid in distensible vessels, a lumped parameter model was developed for 218 arterial segments. The proposed model improved simulation speed by approximately 200-fold while preserved accuracy. Bond graph formulation was used to ensure mass and energy conservation. The model predicted the pressure and flow signatures in the body.

Bond Graph Model of Cerebral Circulation: Toward Clinically Feasible Systemic Blood Flow Simulations

The primary paper Safaei et al. (2018) proposed an anatomically detailed model of the human cerebral circulation that runs faster than real-time on a desktop computer and is designed for use in clinical settings when the speed of response is important. Based on a one-dimensional formulation of the flow of an incompressible fluid in distensible vessels, a lumped parameter model was developed for 218 arterial segments. The proposed model improved simulation speed by approximately 200-fold while preserved accuracy. Bond graph formulation was used to ensure mass and energy conservation. The model predicted the pressure and flow signatures in the body.

Combination of F-ASO and Targeted Medical Therapy in Patients With Secundum ASD and Severe PAH

ObjectivesThis study was conducted to investigate the combined use of fenestrated atrial septal occluder (F-ASO) and targeted medical therapy (TMT) in patients with secundum atrial septal defect (ASD) and severe pulmonary arterial hypertension (PAH). BackgroundTreatment of patients with ASD and severe PAH is still challenging. MethodsAfter ethical approval was obtained, 56 consecutive patients with ASD with severe PAH were included (7 men, 49 women; median age 50.5 years; mean ASD size 26.9 ± 4.6 mm). After 3 months of TMT, transcatheter closure was performed using F-ASO in patients with ratios of pulmonary to systemic blood flow ≥1.5. TMT was continued post-operatively together with 6 months of dual-antiplatelet therapy. The hemodynamic variables during baseline, TMT alone, and combined treatment with F-ASO were compared. ResultsAfter only TMT, systolic pulmonary arterial pressure (−14.5 mm Hg; p < 0.001), pulmonary vascular resistance (−3.9 Wood units; p < 0.001), and exercise capacity (+72.0 m; p < 0.001) improved. Ratio of pulmonary to systemic blood flow increased by 0.9 (p < 0.001), with adverse cardiac remodeling (right ventricular dimension +3.5 mm; p < 0.001). Closure with F-ASO (median size 34.0 mm) led to further decrease in systolic pulmonary artery pressure (−6.0 mm Hg; p < 0.001). Follow-up (median duration 10 months) revealed further improvement in exercise capacity (+60.5 m; p < 0.001), with favorable cardiac remodeling (right ventricular dimension −9.9 mm; p < 0.001). In addition, all fenestrations were stable (p = 0.699), with negligible shunt (median ratio of pulmonary to systemic blood flow 1.1) and no complications. One year later, pulmonary artery pressure was normalized in 8 of 19 patients, and PAH recurred in 5 patients after discontinuation of TMT. ConclusionsIn patients with ASD and severe PAH, combination of F-ASO and TMT was a safe and effective procedure. Compared with TMT alone, the combined treatment further improved exercise capacity, with favorable cardiac remodeling.

The effect of umbilical cord milking on cerebral blood flow in very preterm infants: a randomized controlled study.

To compare the effect of umbilical cord milking (UCM) vs. early cord clamping (ECC) on cerebral blood flow (CBF). Preterm infants <31 weeks' gestation were randomized to receive UCM or ECC at birth. Blood flow velocities and resistive & pulsatility indices of middle and anterior cerebral arteries were measured at 4-6 and 10-12 h after birth as an estimate of CBF. Randomization allocated 37 infants to UCM and 36 to ECC. Maternal and antenatal variables were similar. There were no significant differences between groups in middle or anterior CBF velocities and resistive indices at either study time point. CBF variables were not correlated with mean blood pressure, systemic blood flow, or intraventricular hemorrhage. In very preterm infants, UCM compared with ECC was not shown to change CBF indices during the first 12 h of age or correlate with other hemodynamic measures or with intraventricular hemorrhage. ClinicalTrials.gov: NCT01487187.

Microcirculation-guided protection strategy in hemodynamic therapy.

Microcirculatory shock is a condition defined by the presence of tissue hypoperfusion despite the normalization of systemic and regional blood flow. Currently, more evidence shows that intrinsic septic shock is microcirculatory shock, which results in septic shock that is difficult to resuscitate. At present, treatments are aimed at recovering macro-circulation functions and include fluid resuscitation, vasoactive drugs, positive inotropic drugs, de-obstruction, and even mechanical assistance to improve oxygen delivery. However, the application of these treatments to more accurately improve microcirculation or avoid further microcirculatory damage is more important in clinics. In this article, we discuss the need for microcirculation protection and microcirculation-guided protection strategies in hemodynamic therapies.