Hemodynamic Alterations Research Articles

Utility of doppler ultrasound in early-onset neonatal sepsis: A case-control study.

Early-onset sepsis is one of the leading causes of neonatal morbidity and mortality worldwide and timely diagnosis is, therefore, of paramount importance. As there is a lack of literature regarding early alteration of the cerebral blood flow (CBF) in neonatal sepsis, our study aimed to appraise changes in the CBF velocities and Doppler indices in neonates with early-onset neonatal sepsis (EONS) and to assess its diagnostic accuracy. A total of 99 neonates were recruited in the study; 56 neonates with EONS, and the age-matched 43 neonates without any manifestations of sepsis. A Transcranial Doppler examination and cerebral hemodynamics were assessed in neonates during the first seventy-two hours of life. Doppler indices and CBFV were measured in the anterior cerebral artery (ACA), and middle cerebral artery (MCA), of either side. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated. A significantly lower resistance in Resistivity (RI) and Pulsatility (PI) indices, a significant high end-diastolic velocity (EDV), and relatively higher peak systolic velocity (PSV) in both ACA and MCA have been documented within 72 hours of birth in neonates with EONS compared to the control group of neonates without sepsis. Our Study revealed that assessment of CBF at early hours of birth by Transcranial Doppler examination showed alteration in cerebral hemodynamics in neonates with EONS with an increase in the CBF and a decrease in the resistance. It can be adopted as a bedside, noninvasive tool with immediate diagnostic value.

Comprehensive insights into diabetic nephropathy: pathophysiology, clinical features, and emerging treatments

Diabetic nephropathy (DN) is a leading cause of chronic kidney disease and end-stage renal disease globally, affecting 20–50% of diabetic patients. DN is characterized by albuminuria, retinopathy, and progressive reduction in glomerular filtration rate. The pathophysiology involves chronic hyperglycemia, protein glycosylation, mesangial matrix deposition, glomerular hemodynamic alterations, cytokine release, and renin-angiotensin-aldosterone system activation, leading to kidney damage. Differences in DN mechanisms between type 1 and type 2 diabetes are influenced by additional factors such as aging, obesity, and dyslipidemia. Prevention strategies focus on lifestyle modifications and regular screening. Pharmacological management includes tight glycemic control, blood pressure regulation, renin-angiotensin-aldosterone system blockade, and novel agents like sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide-1 receptor agonists. Emerging therapies targeting inflammatory pathways and innovative medications offer promising avenues for future research. Comprehensive management integrating early detection and advanced pharmacological interventions is crucial to mitigating DN progression and improving patient outcomes.

Using Doppler duplex ultrasound to determine hemodynamic alterations in renal vasculature: Crucial pathophysiological event preceding renal dysfunction in decompensated cirrhosis

BackgroundRenal dysfunction is a watershed event in cirrhosis, often preceded by renal vasoconstriction. However, our reliability on elevated serum creatinine often delays interventions. Measurement of Renal Resistive Index (RI) and Renal Venous Stasis Index (RVSI) by Doppler ultrasound offers insight into renal vasoconstriction. MethodsFifty participants with decompensated cirrhosis with ascites and normal serum creatinine underwent renal Doppler ultrasound for the measurement of RI and RVSI. All patients were compliant with a salt-restricted diet. Individuals aged <18 years, hepatocellular carcinoma, non-cirrhosis-related ascites, pre-existing renal disease, obstructive uropathy, or history of nephrotoxic medication use were excluded. Statistical analyses, including Pearson correlation, regression analysis, and Chi-square/Fisher’s exact tests, were performed to assess the statistical significance between RI, RVSI, and renal parameters. Additionally, the association of RI with the model for end-stage liver disease sodium (MELD-Na) and Child-Turcotte-Pugh (CTP) scores was also assessed. ResultsMajority were males (88%), average CTP score was 11.7, mean MELD-Na score was 20.92, and mean serum creatinine was 1.05 mg/dL. Renal parameters had varying RI values among renal arteries, with the main right and left arteries at 0.615 [standard deviation (SD): 0.089] and 0.638 (SD: 0.083), respectively. RI and RVSI are significantly correlated with serum creatinine. Further, significant correlation between, RI, RVSI values noted with MELD-Na score even when serum creatinine values are normal. ConclusionStrong correlations between serum creatinine, RI, and MELD-Na scores hints at predictive clinical potential. Future research with larger cohorts and extended follow-up is required to gauge clinical utility and its impact on outcomes.

Comparative Efficacy of Intrathecal Hyperbaric Levobupivacaine With Fentanyl Versus Hyperbaric Bupivacaine With Fentanyl in Elective Cesarean Section.

Background In parturient posted for elective cesarean sections, a widely used local anesthetic in the subarachnoid blockade is racemic hyperbaric bupivacaine. Hyperbaric levobupivacaine, the pure S (-) isomer of bupivacaine, was introduced and has since become more widely used in India because of its short duration of motor blockade and reduced risks of neurotoxicity and cardiotoxicity. This study aimed to compare the characteristics of sensory and motor blockade and side effects of equivalent doses of hyperbaric bupivacaine and levobupivacaine with opioid additive fentanyl in order to extend the duration of analgesia during elective cesarean births. Methodology A total of 130 women classified as American Society of Anesthesiologists (ASA) class I and II who are undergoing elective cesarean sections were enrolled in this randomized, prospective, double-blind comparative study after providing written informed consent. They were randomly assigned to one of two groups: Group LF, which included 65 women, obtained 25 mcg (0.5 ml) of fentanyl and 10 mg (2 ml) of hyperbaric levobupivacaine, or Group BF, which included 65 women, received 25 mcg (0.5 ml) of fentanyl and 10 mg (2 ml) of hyperbaric bupivacaine. Pinprick, cold swab, and the Bromage scale are used to assess the characteristics of sensory and motor blockade; hemodynamic alterations and adverse effects are also observed. Results The levobupivacaine group, consisting of 65 participants aged between 21 and 29 years, exhibited fewer side effects and significantly shorter durations of sensory and motor block compared to the bupivacaine group. In both groups, hemodynamic stability is comparable. Levobupivacaine provides analgesia for a significantly shorter period compared to bupivacaine. Conclusions In cesarean procedures, intrathecal hyperbaric levobupivacaine and fentanyl can be effective alternatives to hyperbaric bupivacaine and fentanyl due to their ability to maintain hemodynamic stability while providing adequate sensory and motor blockade.

Establishment of mouse models for severe pulmonary hypertension through 'double-hit' strategies.

Mouse models are crucial for understanding pulmonary hypertension (PH) mechanisms and developing therapies, but existing mouse models under hypoxia only exhibit mild PH. To address this, we established a double-hit model combining unilateral pneumonectomy (LPx) or left pulmonary artery ligation (LPAL) with hypoxia exposure in C57BL/6 mice. Our detailed haemodynamic and histological evaluations post-surgery demonstrated pronounced elevations in right ventricular systolic pressure (RVSP) (LPAL: 41.1±4.63mmHg, P=0.005; LPx: 38.4±2.95mmHg, P=0.002; Sham: 32.1±2.21mmHg) and pulmonary vascular wall thickness (LPAL: 56.9±3.34%, P=0.02; LPx: 54.3±4.65%, P=0.04; Sham: 44.8±3.76%) compared to hypoxia-exposed sham-operated controls, reflecting a more severe PH phenotype. These novel models, which exhibit haemodynamic alterations akin to the established hypoxia with SU5416-induced PH model as per published data, could offer a substantial contribution to future PH research and therapeutic development.

Degenerative mitral stenosis by echocardiography: presentation and outcome

Abstract Aims Degenerative mitral stenosis (DMS) is due to degenerative mitral annular calcification (MAC) and valvular calcification. However, DMS impacts on the outcome, and therefore, potential treatment needs are poorly known. We aimed at evaluating survival after DMS diagnosis by Doppler echocardiography in routine practice. Methods and results A cohort of 2937 (75 ± 12 years, 67% women) consecutive patients were diagnosed between 2003 and 2014 with DMS (diastolic mean gradient ≥ 5 mmHg), with analysis of short- and long-term survival. All patients had overt mitral annular/valvular degenerative calcification without rheumatic involvement. Mean gradient was 6.5 ± 2.4 mmHg, and DMS was considered mild in 50%, moderate in 44%, and severe in 6%. DMS was associated with left atrial enlargement (52 ± 23 mL/m2) and elevated pulmonary pressure (49 ± 16 mmHg) despite generally normal ejection fraction (61 ± 13%). DMS was associated with frequent comorbid conditions (74% hypertension, 58% coronary disease, and 52% heart failure) and humoural alterations (haemoglobin 11.3 ± 1.8 g/dL and creatinine 1.5 ± 1.4 mg/dL). One-year mortality was 22%, most strongly related to older age, higher comorbidity, and abnormal haemoglobin/creatinine but only weakly to DMS severity (with anaemia 42% irrespective of DMS severity, P = 0.99; without anaemia 18, 23, and 28% with mild, moderate, and severe DMS, respectively, P &amp;lt; 0.0004). Long-term mortality was high (56% at 5 years) also mostly linked to aging and weakly to DMS severity [with anaemia P = 0.90; without anaemia: adjusted-hazard ratio: 1.30 (1.19–1.42), P &amp;lt; 0.0001, for moderate vs. mild DMS and 1.63 (1.34–1.98), P &amp;lt; 0.0001, for severe vs. mild DMS]. Conclusion DMS is a condition of the elderly potentially resulting in severe mitral obstruction and haemodynamic alterations. However, DMS is frequently associated with severe comorbidities imparting considerable mortality following diagnosis, whereas DMS severity is a weak (albeit independent) determinant of mortality. Hence, patients with DMS should be carefully evaluated and interventional/surgical treatment prudently considered in those with limited comorbidity burden, particularly without anaemia. Keywords: Degenerative Mitral Stenosis; Outcome; Natural history; Ecocardiography; Mitral Stenosis.

Perioperative Complications in Percutaneous Nephrolithotomy: Predictive Risk Factors and Hemodynamic Alterations.

Background Percutaneous nephrolithotomy (PCNL) is one of the most frequently used methods of treating large and/or complex kidney stones. Despite the growing interest in this area, there are relatively few papers that report studies of the changes in hemodynamics in the perioperative period and the potential factors that might influence the patient's condition. This aspect, however, has not been well described in the current literature, although fluctuations in blood pressure, temperature, and electrolyte balance during surgery may also lead to development of complications. Objectives In this study, variations in vital signs during surgery and between surgeries of 134 patients who underwent PCNLwere analyzed in relation to other predisposing factors such as hypothermia and the need for blood transfusion. Methods Biochemical data such as systolic blood pressure (SBP) and diastolic blood pressure (DBP), temperature, hemoglobin (Hb), hematocrit (Hct), and serum sodium and potassium were assessed at admission, during PCNL, and at 24 hours after surgery in 134 patients. In this study logistic regression was used to assess the influence of factors such as age, BMI (body mass index), surgery duration, volume of irrigation fluid, number of tracts, estimated blood loss, hypothermia, and requirement of red blood cell transfusions. Results The mean arterial pressure declined during surgery as compared to the preoperative value, reaching a value of 97.34 during the operation. The monitored mean temperature of the patient during the perioperative period was therefore reduced, with a small increase towards the end of the surgery. In the plasma concentrations, there was a decrease compared to pre- and postoperative values, and there was also a decline in 48-hour Hb, Hct, and sodium values. The analysis identified the volume of irrigation fluid as a predictor of mild hypothermia risk. A longer surgery time along with more tracts and worse condition of the patient meant that the patient needed more blood transfusion. It was also noted that none of them influenced the amount of Hb that was lost. Conclusion Variability in the recorded ABCs (airway, breathing, and circulation) before and after PCNL procedures was normative. Despite hypothermia being associated with the volume of irrigation fluids used in surgeries, most of the transfusions were administered in patient-complicated operations and critical states. This suggested that there was potential in defining the modifiable factors that worsen clinically reported outcomes to assist in enhancing protocol.

The onset of coarctation of the aorta before birth: Mechanistic insights from fetal arch anatomy and haemodynamics

Accurate prenatal diagnosis of coarctation of the aorta (CoA) is challenging due to high false positive rate burden and poorly understood aetiology. Despite associations with abnormal blood flow dynamics, fetal arch anatomy changes and alterations in tissue properties, its underlying mechanisms remain a longstanding subject of debate hindering diagnosis in utero. This study leverages computational fluid dynamics (CFD) simulations and statistical shape modelling to investigate the interplay between fetal arch anatomy and blood flow alterations in CoA. Using cardiac magnetic resonance imaging data from 188 fetuses, including normal controls and suspected CoA cases, a statistical shape model of the fetal arch anatomy was built. From this analysis, digital twin models of false and true positive CoA cases were generated. These models were then used to perform CFD simulations of the three-dimensional fetal arch haemodynamics, considering physiological variations in arch shape and blood flow conditions across the disease spectrum. This analysis revealed that independent changes in the shape of.the arch and the balance of left-to-right ventricular output led to qualitatively similar haemodynamic alterations. Transitioning from a false to a true positive phenotype increased retrograde flow through the aortic isthmus. This resulted in the appearance of an area of low wall shear stress surrounded by high wall shear stress values at the flow split apex on the aortic posterior wall opposite the ductal insertion point.Our results suggest a distinctive haemodynamic signature in CoA characterised by the appearance of retrograde flow through the aortic isthmus and altered wall shear stress at its posterior side. The consistent link between alterations in shape and blood flow in CoA suggests the need for comprehensive anatomical and functional diagnostic approaches in CoA. This study presents an application of the digital twin approach to support the understanding of CoA mechanisms in utero and its potential for improved diagnosis before birth.

The mineralocorticoid receptor in diabetic kidney disease.

Diabetes mellitus is one of the leading causes of chronic kidney disease and its progression to end-stage kidney disease (ESKD). Diabetic kidney disease (DKD) is characterized by glomerular hypertrophy, hyperfiltration, inflammation, and the onset of albuminuria, together with a progressive reduction in glomerular filtration rate. This progression is further accompanied by tubulointerstitial inflammation and fibrosis. Factors such as genetic predisposition, epigenetic modifications, metabolic derangements, hemodynamic alterations, inflammation, and inappropriate renin-angiotensin-aldosterone system (RAAS) activity contribute to the onset and progression of DKD. In this context, decades of work have focused on glycemic and blood pressure reduction strategies, especially targeting the RAAS to slow disease progression. Although much of the work has focused on targeting angiotensin II, emerging data support that the mineralocorticoid receptor (MR) is integral in the development and progression of DKD. Molecular mechanisms linked to the underlying pathophysiological changes derived from MR activation include vascular endothelial and epithelial cell responses to oxidative stress and inflammation. These responses lead to alterations in the microcirculatory environment, the abnormal release of extracellular vesicles, gut dysbiosis, epithelial-mesenchymal transition, and kidney fibrosis. Herein, we present recent experimental and clinical evidence on the MR in DKD onset and progress along with new MR-based strategies for the treatment and prevention of DKD.

P168 CHARACTERIZATION OF THE HEMODYNAMIC PATTERN OF CONTROLLED HYPERTENSIVE PATIENTS

Background: Hemodynamic alterations have been described in hypertensive disease. However, we still do not know if the identification of an altered hemodynamic pattern in patients with controlled hypertension could predict cardiovascular risk or evolution of hypertension. Objective: to identify the hemodynamic pattern of hypertensive patients with BP values in goals. Methods: Controlled hypertensive subjects were recruited (n = 107) and included a control group of normotensive subjects (n: 35.9). A non-invasive hemodynamic study (Z Logic, lying down / standing) was performed, and the cardiac index (CI) and vascular resistance index (VRI) data were recorded for the determination of the hemodynamic pattern. Hypodynamic pattern was considered: CI &lt;2.5 L / min / m2 and VRI&gt; 2500 dynas.seg.cm-5.m2; Hyperdynamic pattern IC&gt; 4,4 L / min / m2 and VRI &lt;2500 dynas.seg.cm-5.m2 Results: The SBP / DBP of the HTA group was 133.09 +/- 6.01 / 82.4 +/-7.2 mm Hg; and of the NT group was SBP/ DBP 123.6 +/- 9.7 / 75.5 +/- 8.9. The CI and VRI of the HTA group obtained was 2.81 l / m2 / min and 2842.31 dynas that, without corresponding to a hypodynamic pattern, showed a predominance of the VRI increase. In the control group of NT subjects, the values were 3.23 and 2289.23, respectively, corresponding to a normal pattern. The values obtained were different between both groups (p &lt;.05). Conclusions: Controlled hypertensive patients with hypertension goals have a hemodynamics pattern with an increase in the VRI different from that of normotensive subjects. These results coincide with those reported by Ferrario and col. The relevance of the imbalance found could only be analyzed in the context of long-term follow-up to identify whether it is a predictor of CV events and / or complications.

Abstract 65: Postpartum Alterations of Middle Cerebral Artery Reactivity and Hemodynamics in a Transgenic Rat Model of Preeclampsia

Evidence suggests that cerebrovascular disease is a leading cause of morbidity and mortality in women with preeclampsia (PE), however the mechanisms are unknown. In a transgenic rat displaying PE-like syndrome (TGA-PE: female transgenic for angiotensinogen mated to male transgenic for renin), we have shown postpartum alterations in cerebrovascular hemodynamics suggesting dysfunctional autoregulation. We hypothesize that impaired middle cerebral artery (MCA) reactivity contributes to the cerebrovascular dysfunction in this model. High frequency ultrasound was used to determine the pulsatility index (PI) of left MCA (LMCA). Vascular responses were studied in isolated segments of LMCA from SD (n= 12) and TGA-PE (n=8) two months post-delivery. Arteries were mounted on a Multi-Wire Myograph for determination of isometric force (USA-DMT). The contractile responses to K + 75 mM and endothelin-1 (ET-1, 10 -11 -10 -7 M) were measured in basal tone. Vasodilatory responses to acetylcholine (ACh, 10 -11 -10 -4 M) were determined in arteries pre-constricted with the thromboxane agonist U46619 (10 -7 M); the maximal response ( R MAX ) and sensitivity (pD 2 =-Log[EC 50 ]) were analyzed. Our data show that systolic blood pressures were elevated in TGA-PE versus SD at 2 months post-delivery (144.9±2.7 vs. 118.4±2.5, p&lt;0.05; n=10-19). However, the PI was lower in TGA-PE vs. SD (0.96±0.05 vs. 1.31±0.06; p&lt;0.05, n=8-13). No differences in basal tone of MCA segments were observed, whereas TGA-PE arteries displayed a lower optimal diameter (175±4 μm vs. 217±4 μm; p&lt;0.05) and a lower response to K + (0.85±0.11 vs. 1.29±0.1 mN/mm; p&lt;0.05) compared to SD. Vasodilatation to acetylcholine was similar (ACh MAX : 79±8 vs. 70±9%) with a lower sensitivity (pD 2 : 5.2±0.1 vs. 6.7±0.4; p&lt;0.05) in TGA-PE. The contractile response to ET-1 was increased in TGA-PE arteries (ET-1 MAX : 159±7 vs. 129±6 % K MAX ; p&lt;0.05) with no differences in sensitivity (pD 2 : 8.8±0.1 vs. 8.9±0.1). Our data demonstrate structural and functional differences in MCA from TGA-PE vs. SD at 2 months postpartum. In addition to a smaller functional diameter, a lower non-receptor dependent contraction may explain the lower resistance of MCA observed in the preeclamptic model. We conclude that attenuated vasodilatory and increased contractile responses of MCA could promote cerebrovascular dysfunction in this model, and that these adaptations may contribute to cerebrovascular pathology in postpartum preeclamptic state. Supported by NIH 1R01HL155420

Obesity-Related Glomerulopathy: Epidemiology, Pathogenesis, and Current Treatments

Obesity-related glomerulopathy (ORG) is a kidney disease characterized by glomerulomegaly with or without focal segmental glomerulosclerosis. With the increase in worldwide obesity rates, the number of ORG patients has also risen rapidly. Approximately 10% of ORG patients have been found to progress to the end stage of renal disease 6.2 years after diagnosis. The pathogenesis of ORG is complex, involving altered renal hemodynamics, activation of the renin–angiotensin–aldosterone system, insulin resistance, and abnormal lipid metabolism and adipokines. Despite the numerous strategies to lose weight as treatment for ORG, ranging from lifestyle and diet changes to bariatric surgery and medications, approved and marketed weight-loss drugs often have potential side effects and perform below expectations. Recently, new glucose-lowering drugs that also reduce body weight and improve kidney function have garnered attention. In particular, several large clinical trials have confirmed the efficacy and safety of sodium–glucose cotransporter 2 inhibitors and glucagon-like peptide-1 receptor agonists in reducing weight and preserving kidney function. This article provides a brief review of the epidemiology, pathogenesis, and treatment strategies of ORG.

P108 DIFFERENCES IN BLOOD PRESSURE CONTROL BASED ON HYPERTENSION SUBTYPE IN PATIENTS WITH A DE NOVO DIAGNOSIS: A RETROSPECTIVE COHORT STUDY

Background and Objective: Currently, the selection of antihypertensive pharmacological treatment is carried out without considering whether only systolic or diastolic hypertension is present or both pressures are elevated. It is unknown whether the selection of individualized pharmacological treatment according to arterial hypertension (AH) subtype leads to greater blood pressure (BP) control. Therefore, this study aims to evaluate the association between the selection of pharmacological treatment based on AH subtype and BP control. Methods: This was a real-world cohort study that included 1,397 Latin American subjects with a de novo diagnosis of AH who received antihypertensive pharmacological treatment following current guidelines. Retrospectively, patients were classified by AH subtype according to the pattern of systolic or diastolic predominance of AH. Also, appropriateness of the pharmacological treatment was assessed based on AH subtype and the underlying hemodynamics of each subtype. BP control at the follow-up, within the first 12 weeks after diagnosis, was defined as &lt;140/90 mmHg. Results: Among the subjects included in the study (n=1,397), the mean age was 52.4±13.2, and body mass index 28.8±4.9 kg/m2; 56.7% were women and 50.6% achieved BP control. The median time to the follow-up after diagnosis was 55 days (IQR 32-89 days). Regarding hemodynamic variables, the mean heart rate was 76.1±7.4 beats per minute, systolic blood pressure 147±13.9 mmHg, diastolic blood pressure 86.4±11.2, mean arterial pressure 108.0±9.5 mmHg, and pulse pressure 61.1±16.1 mmHg. The most frequent AH subtype was isolated systolic hypertension (47.3%). Initiation of appropriate antihypertensive pharmacological treatment was associated with greater BP control (OR 2.17; 95% CI 1.49 to 3.15; P value &lt;0.001) (Figure). The patients who did not reach BP control presented a higher frequency of divergent systolic-diastolic hypertension subtype, and greater hemodynamic alterations. Conclusions: Appropriate selection of pharmacological treatment based on AH subtype is associated with better BP control in patients with newly diagnosed AH.

Exploring the contribution of carotid artery disease to the onset of non-arteritic ischemic optic neuropathies: A systematic review.

The role of carotid artery disease (CAD) in the development of various types of ocular arterial occlusive disorders has often been reported. This systematic review aims to evaluate and review the current evidence regarding the role of CAD and the subsequent carotid artery hemodynamic alterations in the development of non-arteritic anterior (NA-AION) and posterior (NA-PION) ischemic optic neuropathy. We systematically reviewed studies following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. We systematically searched PubMed, Embase, and Scopus databases for relevant studies that clearly assessed the role of CAD and the subsequent carotid artery hemodynamic alterations in the development of NA-AION and NA-PION. All studies that examined the associations between CAD and the development of NA-AION and NA-PION in adults aged 18 years or older were synthesized. Quality assessment using the Newcastle-Ottawa Scale (NOS), and Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Case Reports and Case-Series were also conducted. Our search identified 1933 manuscripts published in the English language. The number of participants with non-arteritic ischemic optic neuropathy (NA-ION) ranged from 1 to 191, with a total of 478 patients experiencing either NA-AION (410 out of 478), NA-PION (13 out of 478), or a combination of thereof (1 out of 478). The number of participants with NA-ION due to atherosclerosis ranged from 1 to 191, with a total of 376 patients. Although carotid artery disease may rarely contribute to the development of NA-ION, it should be considered as a possible cause of NA-ION.

Dissecting contributions of pulmonary arterial remodeling to right ventricular afterload in pulmonary hypertension.

Pulmonary hypertension (PH) is defined as an elevation in the right ventricle (RV) afterload, characterized by increased hemodynamic pressure in the main pulmonary artery (PA). Elevations in RV afterload increase RV wall stress, resulting in RV remodeling and potentially RV failure. From a biomechanical standpoint, the primary drivers for RV afterload elevations include increases in pulmonary vascular resistance (PVR) in the distal vasculature and decreases in vessel compliance in the proximal PA. However, the individual contributions of the various vascular remodeling events toward the progression of PA pressure elevations and altered vascular hemodynamics remain elusive. In this study, we used a subject-specific one-dimensional (1D) fluid-structure interaction (FSI) model to investigate the alteration of pulmonary hemodynamics in PH and to quantify the contributions of vascular stiffening and increased resistance towards increased main pulmonary artery (MPA) pressure. We used a combination of subject-specific hemodynamic measurements, ex-vivo mechanical testing of arterial tissue specimens, and ex-vivo X-ray micro-tomography imaging to develop the 1D-FSI model and dissect the contribution of PA remodeling events towards alterations in the MPA pressure waveform. Both the amplitude and pulsatility of the MPA pressure waveform were analyzed. Our results indicated that increased distal resistance has the greatest effect on the increase in maximum MPA pressure, while increased stiffness caused significant elevations in the characteristic impedance. The method presented in this study will serve as an essential step toward understanding the complex interplay between PA remodeling events that leads to the most severe adverse effect on RV dysfunction.

Virtual flow diverter deployment and embedding for hemodynamic simulations

Flow-diverter stents offer clinicians an effective solution for treating intracranial aneurysms, especially in cases where other devices may be unsuitable. However, strongly deviating success rates among different centres, manufacturers, and aneurysm phenotypes highlight the need for better in-situ studies of these devices. To support research in this area, virtual stenting algorithms have been proposed that, combined with computational fluid dynamics, provide insights into the hemodynamic alterations induced by the device. Yet, many existing algorithms rely on uncertain parameters, such as the forces applied during operation, fail to predict the length of the device after deployment, or lack robust validation steps, raising concerns about their reliability. Therefore, we developed a robust deployment technique that builds upon the geometrical features of the vessel and includes advancements from previous works. The algorithm is detailed and validated against literature examples, in-vitro experiments, and patient data, achieving a mean angular error below 5° in the latter. Furthermore, we describe and demonstrate how the deployed device can be embedded in a computational mesh using open-source tools and anisotropic meshing routines.

Investigation of the effects of single and two-muscle horizontal rectus surgeries on macular microvasculature.

To investigate the changes in posterior segment hemodynamics caused by horizontal rectus muscle surgeries using the optic coherence tomography angiography (OCTA). Patients who underwent at least one horizontal rectus recession, resection, or combination surgery were included. The patients were evaluated with an OCTA preoperatively and 30days postoperatively. Postoperative changes in superficial capillary plexus (SCP)-vessel density (VD), deep capillary plexus (DCP)-VD, foveal avascular zone (FAZ) area and choriocapillaris (CC)-flow area parameters were examined. The mean differences (Δ) for the parameters in which significant changes were detected in the whole operated eyes group were compared between the single- and two-muscle surgery groups. Twenty-five eyes of 24 patients with an average age of 16.40 ± 6.75years (5-29) were included. Of the eyes, 10 underwent single muscle recession surgery. Two-muscle surgeries were performed in 15 eyes. SCP-VD in the superior parafoveal region increased significantly postoperatively (53.23 ± 4.11% vs. 54.54 ± 3.67%, p = 0.032). For DCP-VD, there was a statistically significant increase in all zones, except the superior hemisphere and fovea regions (p < 0.05 for all). FAZ area did not change significantly (p = 0.207). There was a significant increase in the CC-flow area (2.171 ± 0.146 mm2 vs. 2.232 ± 0.115 mm2, p = 0.013). There was a significant difference between the two groups only for the Δ SCP-VD/parafovea superior value (-0.62 ± 0.98 vs. 1.57 ± 3.07, p = 0.019). Conventional horizontal rectus muscle surgeries may cause alterations in posterior segment hemodynamics. The number of muscles incised does not seem to greatly affect the magnitude of changes that occur. What is known • After conventional horizontal rectus muscle surgeries, the anterior ciliary arteries are not recanalized, instead, anterior segment blood flow is maintained by increasing the flow in the long posterior ciliary arteries. • Previous studies using Doppler ultrasonography have shown increased flow in the ophthalmic artery, central retinal artery and long posterior ciliary arteries. What is new • In this study, significant increases were observed in superficial and deep capillary plexus-vessel density and choriocapillaris-flow area parameters in the first postoperative month with optic coherence tomography angiography device. • Hemodynamic increases in both retinal and choroidal vasculature were detected in the early period after conventional horizontal rectus muscle surgeries. • The number of muscles incised does not seem to greatly affect the magnitude of changes that occur.

Comparative analysis of peri-nidal cerebral blood flow and metabolism using a novel quantitative 15O-PET method in patients with arteriovenous malformations.

To effectively treat cerebral arteriovenous malformations (AVMs), peri-nidal flow regulation and metabolic status must be understood. In this study, we used 15O-oxygen positron emission tomography (PET) post-processing analysis to investigate vascular radioactivity in the nidal region of AVMs. Single-dynamic PET imaging was performed on seven unruptured AVM patients during the sequential inhalation of 15O2 and C15O2. A previously validated dual-tracer basis function method (DBFM) was employed to calculate parametric images. The results of our study were as follows. First, in remote and contralateral AVM regions, DBFM and a previous approach of dual-tracer autoradiography (DARG) showed strong positive correlations in cerebral blood flow (CBF), cerebral oxygen metabolism rate (CMRO2), and oxygen extraction fraction. Second, peri-nidal CBF and CMRO2 correlation was lower, and overestimation occurred with DARG compared to with DBFM. Third, on comparing DBFM to quantitative 123I-iodoamphetamine single-photon emission computed tomography (SPECT), CBF correlated significantly. In contrast, the correlation between DARG and quantitative 123I-iodoamphetamine-SPECT was weaker in the peri-nidal regions. Fourth, analysis of tissue time-activity curves demonstrated good reproducibility using the novel formulation in the control, peri-nidus, and core nidal regions, indicating the adequacy of this approach. Overall, the DBFM approach holds promise for assessing haemodynamic alterations in patients with AVMs.

Hemodynamically significant patent ductus arteriosus profile in preterm neonates (26-34 weeks' gestation) undergoing surfactant replacement therapy in India: a prospective observational study.

Surfactant administration significantly improves respiratory outcomes in preterm infants with respiratory distress syndrome (RDS). However, surfactant administration may lead to hemodynamic alterations, particularly in the heart, affecting the patent ductus arteriosus (PDA), the consequences of which are not fully understood. This prospective observational study took place in an Indian neonatal care unit from July 2019 to November 2020, enrolling preterm neonates (26-34 weeks' gestation) with RDS needing non-invasive positive pressure ventilation. They were divided into two groups: those who received surfactant while on respiratory support and those who did not. All newborns in the study had an initial echocardiogram within 24 h to detect PDA flow. Subsequent echocardiograms were conducted between 48 and 72 h or earlier based on symptoms. Of 220 infants requiring respiratory support, 84 were enrolled, with 42 in each group. While demographic variables were similar, the surfactant group had a lower median gestational age (29.0 vs. 31.0 weeks). In the surfactant group, a significantly higher percentage of neonates had hemodynamically significant PDA (hsPDA) compared to the non-surfactant group (54.76% vs. 26.19%, P-value = .008). Multiple logistic regression found no significant association between gestation, birth weight, or shock and hsPDA occurrence. Pulmonary hemorrhage occurred more often in the surfactant group. Bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH) > grade 2, and necrotizing enterocolitis (NEC) ≥ grade 2 did not differ significantly between the groups. Surfactant therapy via the less invasive surfactant administration technique was associated with a higher incidence of hsPDA. While surfactant is crucial for neonatal respiratory care, its potential hemodynamic effects, including hsPDA, should be considered.

Advances in the diagnosis and poor prognosis of diabetic hyperfiltration

Glomerular hyperfiltration(GHF), as an early manifestation of prediabetes and diabetic kidney disease, occurs mainly by the mechanism of glomerular-tubular feedback and hemodynamic alterations, and the risk of hyperfiltration can be elevated in younger patients, shorter duration of the disease, poor glycemic control, and high-protein, low-salt diet. Currently, there is no recognized standard for the definition of GHF, GHF lacks typical clinical manifestations, imaging diagnostic criteria are unclear, and GHF-related laboratory markers need to be further studied. Hyperfiltration, if not diagnosed and intervened in time, can accelerate the damage of nephron and the rate of nephropathy progression, and increase the risk of complications and death. Sodium-glucose cotransporter 2 inhibitor(SGLT2i), glucagon-like peptide-1 receptor agonist(GLP-1RA)and so on can effectively reverse the hyperfiltration state. Clinical attention should be paid to the diagnosis of diabetic hyperfiltration and the prevention of its poor prognosis.