Pressure Recordings Research Articles

Assessing the Optimal Dose of Mivacurium for Modified Rapid Sequence Intubation in Emergency Surgical Settings: A Randomized, Double-Blind Trial

Background: Modified rapid sequence intubation (RSI) is crucial in emergency surgery, particularly for patients with a full stomach, as it allows for the administration of general anesthesia (GA). Objectives: This work aimed to evaluate mivacurium effectiveness and optimal dose in modified RSI. Methods: This randomized double-blind study involved 100 patients, aged between 20 - 60 years, of both sexes, with the American Society of Anesthesiologists physical status classification of I - III, who were undergoing emergency surgery under GA. Patients were randomized into two equal groups and received mivacurium in a dose of 0.3 mg/kg in group M1 or 0.4 mg/kg in group muscarinic-2 (M2). Results: Intubating conditions were significantly better in group M2 than in group M1. The onset of adequate muscle relaxation was significantly earlier in group M2 than in group M1 (P < 0.001). At the third minute, mean arterial blood pressure recordings were significantly lower in group M2 (P = 0.04) than in group M1. The recovery time was significantly longer in group M2 than in group M1 (P < 0.001). Conclusions: Mivacurium in a 0.4 mg/kg dose resulted in more favorable intubating conditions during RSI and a more profound, earlier onset of muscle relaxation, but with a longer recovery time compared to the 0.3 mg/kg dose.

Perioperative Evaluation and Monitoring of Percutaneous Balloon Compression in Treatment of Trigeminal Neuralgia

BACKGROUND AND OBJECTIVES: Multiple factors may influence the clinical outcomes of percutaneous balloon compression (PBC), including intraluminal balloon pressure, volume, and Meckel's cave volume. In this article, we aimed to investigate the clinical value of the perioperative assessment and monitoring of balloon compression in the treatment of trigeminal neuralgia (TN). METHODS: Thirty-seven patients who underwent PBC were prospectively enrolled. The patient underwent preoperative high-resolution 3.0-T MRI for the 3-dimensional reconstruction of Meckel's cave, while intraoperative recordings of intraluminal pressure and balloon volume were conducted simultaneously. Primary outcomes included postoperative numbness and pain recurrence up to 24 months after discharge. RESULTS: Sensory deficiency was primarily reported within the first month, and approximately 38% of the patients presented with symptomatic numbness in the facial region. Subgroup analysis indicated no statistically significant difference in intraluminal balloon pressure between patients with facial numbness and asymptomatic individuals. This impairment in trigeminal sensation eventually recovered at the 24-month follow-up. By contrast, the long-term recurrence rate of TN was approximately 25% (5/20 patients) 2 years postoperatively. Furthermore, we found that the intraluminal balloon pressure was significantly lower among patients with recurrent pain (102.8 ± 11.0 vs 135.7 ± 5.1 kPa, P < .05). Although no significant differences in balloon or Meckel's cave volume were observed between subgroups, we found a positive and significant correlation between the volume of Meckel's cave and balloon. CONCLUSION: Facial numbness remains a common but short-term symptom of PBC for TN. This study indicates that a higher intraluminal balloon pressure may be associated with a lower risk of recurrent trigeminal pain. Preoperative reconstruction of Meckel cave may help to predict the volume of intraoperative balloon compression. We consider it feasible and necessary to conduct a perioperative assessment of balloon compression in the treatment of TN.

Impact of a standard regimen of Churu 25, Kobjee 13, and Agar 15 on blood pressure recordings in patients with Thrak-loong

Impact of a standard regimen of Churu 25, Kobjee 13, and Agar 15 on blood pressure recordings in patients with Thrak-loong

Analysis of field monitoring of precipitation and pore pressure over seven years at Morro do Boi of Serra do Mar/Brazil

The stability of slopes or the occurrence of mass movements is directly related to the incidence of rainfall. In this work a qualitative analysis of the historical series was made for the period between May 2012 and February 2019, where the development of pore pressures was evaluated, analyzing the behaviors of the instruments, correlating their readings with precipitation and with variations in the water table. Pore pressure was measured using vibrating wire piezometers, and precipitation data was collected using pluviometers with tipper buckets, whose readings were obtained by a datalogger model ML1-FL. From the data collected, it was possible to estimate the duration of a rainfall event for the soil, as that time interval between the occurrence of rain and the dissipation of excess pore pressure. These intervals are between 3 and 26 days in duration. The main results were: the period between the end of June and August is the driest and the highest precipitation occurs from December to early June; Precipitation of up to 100 mm of daily accumulation is well distributed throughout the year and occurs in all seasons. The pore pressure values developed were low, with a maximum of 9.3 kPa for the deepest piezometer on elevation 92.40 m. There is a delay between the occurrence of precipitation and the recording of the peak pore pressure. The in-depth knowledge of variations in precipitation and pore pressure can support the development of more robust geotechnical engineering projects. This preventive approach, based on concrete data and correlations, offers a more reliable strategy for mitigating the risks associated with landslides, directly contributing to the safety and continuous operation of the BR-101/SC highway.

Dynamic Estimation of Cardiovascular State From Arterial Blood Pressure Recordings.

Real-time estimation of patient cardiovascular states, including cardiac output and systemic vascular resistance, is necessary for personalized hemodynamic monitoring and management. Highly invasive measurements enable reliable estimation of these states but increase patient risk. Prior methods using minimally invasive measurements reduce patient risk but have produced unreliable estimates limited due to trade-offs in accuracy and time resolution. Our objective was to develop an approach to estimate cardiac output and systemic vascular resistance with both a high time resolution and high accuracy from minimally invasive measurements. Using the two-element Windkessel model, we formulated a state-space method to estimate a dynamic time constant - the product of systemic vascular resistance and compliance - from arterial blood pressure measurements. From this time constant, we derived proportional estimates of systemic vascular resistance and cardiac output. We then validated our method with a swine cardiovascular dataset. Our estimates produced using arterial blood pressure measurements not only closely align with those using highly invasive measurements, but also closely align when derived from three separate locations on the arterial tree. Moreover, our estimates predictably change in response to standard cardiovascular drugs. Overall, our approach produces reliable, real-time estimates of cardiovascular states crucial for monitoring and control of the cardiovascular system.

Automatic quantification of pressure waveform damping during cardiac catheterisation using artificial intelligence

Abstract Background Undetected abnormalities in the aortic pressure waveform caused by damping of the signal can lead to complications during coronary angiography. Most commonly caused by over engagement of the catheter into the coronary ostium, the severity of pressure damping can be visually quatified by experience operators: it starts with the loss of the dicrotic notch, progresses to varying degrees of waveform "ventricularisation" and finally reaches a severe form with loss of the typical coronary waveform. The clinical consequences of undetected pressure damping are proportional to its severity, and include underestimation of stenosis severity during physiological assessment, vessel injury and, catastrophically, ventricular fibrillation. An automated approach to quantify pressure damping severity would improve patient safety by eliminating the need for constant operator attention during the procedure. Purpose To develop an index to automatically quantify the degree of pressure waveform damping using artificial intelligence. Methods 761 aortic pressure recordings obtained during pressure wire assessments and ranging from normal to severely damped, were manually processed into 1561 shorter recordings of 6-8 beats each. Recordings were then randomly allocated into separate training and validation datasets in a 70:30 ratio. The training and validation datasets were labelled by two separate groups of experts: 5 labelled the training dataset and 4 labelled the validation dataset. All experts were practicing interventional cardiologists who had undertaken doctoral and post-doctoral research in coronary physiology. 14490 individual expert discriminations were used to train the neural network. A purpose-built platform was used to label pressure waveforms. A neural network was trained using the training dataset. The validation dataset was then assessed by the neural network. The score output was transformed into an index which ranged from 0 (normal waveform) to 1 (severely damped). The correlation between expert consensus and the AI derived index was compared using Spearman’s Rho and numerical agreement assessed with Bland and Altman analysis. Results The AI derived index was able to continuously discriminate progressive degrees of pressure damping and demonstrated excellent correlation with the expert consensus score (Spearman’s rho 0.89) and numerical agreement on Bland and Altman analysis (bias +0.05 and limits of agreement ±0.21). Individual expert’s scores showed a range of agreement with the expert consensus score (Spearman’s rho 0.75-0.94, mean 0.86). The AI index agreed with expert consensus more closely than each expert agreed with each other. Conclusion An AI derived index can provide an automated, real-time and operator-independent quantification of the degree of aortic pressure waveform damping, improving precision of physiological assessment and potentially increasing patient safety during coronary angiography.

Automated cardiac arrest detection using a photoplethysmography wristband: algorithm performance in relation to sex, skin color type and arm hair density

Abstract Background While survival from witnessed out-of-hospital cardiac arrest (OHCA) has improved, this is not the case for unwitnessed cardiac arrest as the event goes unnoticed. Automated cardiac arrest detection and alerting through a wristband is considered a promising technique also facilitating early assistance for this large group. In the DETECT-1 study, a photoplethysmography(PPG) algorithm for circulatory arrest detection was developed in patients with induced circulatory arrest. However, patient characteristics, such as skin color and arm hair density, can influence the accuracy of the PPG signal. Thus, we performed further analyses to study the effect of patient characteristics on the algorithm’s performance. Purpose To assess the performance of the developed PPG algorithm for cardiac arrest detection in relation to sex, skin color type and arm hair density. Methods Patients who underwent short-lasting circulatory arrest induction during transcatheter aortic valve implantation, ventricular tachycardia ablation or subcutaneous ICD implantation wore a PPG wristband during the procedure. Continuous ECG and invasive blood pressure recordings served as reference standards. A PPG algorithm for circulatory arrest detection was developed. The algorithm’s performance was assessed in subgroups based on sex, skin color type (according to the Fitzpatrick scale), and arm hair density. The sensitivity for the detection of circulatory arrest and false positive alarms were compared between the different subgroups. Results In total, 151 patients were included in the current analysis. Analyzed data consisted of 159 hours of PPG data including 176 induced circulatory arrest events. The population consisted of 57 (38%) females and 94 (62%) males. The sensitivity for circulatory arrest detection was 100% in the female group vs. 98% in the male group (p=ns); false positive alarms occurred in 4 females and 9 males, resulting in a positive predictive value (PPV) of 94% and 92% (p=ns), respectively. Within the skin color subgroup analysis, 114 (75%) patients had skin color type I or II, and 37 (25%) patients had a skin color type III, IV, V or VI. There were no differences in sensitivity (p=ns) and PPV (p=ns) in the skin color subgroup (table 1). The population consisted of 106 (71%) patients with nil or sparse arm hair density, 43 (29%) patients with moderate or dense arm hair density, and 2 not reported. There were no differences in sensitivity (p=ns) and PPV (p=ns) within the arm hair density subgroup (table 1). Conclusions Automated cardiac arrest detection using a smartwatch is feasible and its accuracy is not affected by sex, skin color type or arm hair density in this study. Further study is needed to assess performance of the algorithm in a larger sample size and a more diverse study population. If proven to be effective, automated cardiac arrest detection has the potential to improve survival from OHCA.Sensitivity/PPV for arrest detection

Noninvasive Assessment of Temporal Dynamics in Sympathetic and Parasympathetic Baroreflex Responses.

The baroreflex system is crucial for cardiovascular regulation and autonomic homeostasis. A comprehensive assessment requires understanding the simultaneous temporal dynamics of its multiple functional branches, which traditional methods often overlook. To develop and validate a noninvasive method for simultaneously assessing the temporal dynamics of sympathetic and parasympathetic baroreflexes using pulse contour analysis and the sequence method. Beat-to-beat blood pressure and ECG recordings were analyzed from 55 preoperative cardiothoracic surgery patients in the supine position and 21 subjects from the EUROBAVAR dataset in both supine and standing positions. Systolic arterial pressure (SAP), interbeat interval (IBI), cardiac output (CO), myocardial contraction (dP/dtmax), and systemic vascular resistance (SVR) were estimated using pulse contour analysis. Baroreflex sensitivity (BRS) was calculated via the sequence method and correlated with hemodynamic and heart rate variability (HRV) parameters. Parasympathetic BRS for IBI was correlated with the root mean square of successive differences of ECG RR intervals (RMSSD-HRV) at 0-beat delay. Sympathetic BRS for SVR strongly correlated with SVR, CO, and RMSSD-HRV, particularly at 3-beat delay, and was uniquely associated with SAP at 1-beat delay. Sympathetic BRS for dP/dtmax correlated with dP/dtmax at 1-beat delay. In contrast, BRS for CO correlated with CO and SVR at 0- and 3-beat delays. Postural changes mainly affected parasympathetically-mediated BRS for IBI and, to a lesser extent, the sympathetic vascular and myocardial branches. This method effectively captures multiple baroreflex responses and their temporal dynamics, revealing distinct autonomic mechanisms and the impact of postural changes. Further validation is warranted.

Early wave reflection of carotid artery is associated with 18F-FDG PET hypometabolism in Alzheimer's brain areas of cognitively normal adults.

Arterial stiffening likely plays a role in Alzheimer disease (AD) pathogenesis. The current study investigated whether inter-individual variations in arterial stiffness and pressure wave parameters were associated with 18F-FDG positron emission tomography (PET) metabolism in AD-associated brain areas throughout adulthood, independently of age and before the onset of any neuropsychological disorders. A prospective, large age-range population of 67 patients (17 young, 16 middle-aged, and 34 older adults; 37 women) underwent a: brain 18F-FDG PET, blood pressure recording, and carotid/femoral pulse wave-based measurements, including the time-to-peak of the reflected backward carotid pulse wave (bT), on the same day. Multivariable and quantitative voxel-to-voxel analyses (P-voxel < 0.005, corrected for cluster volumes) were conducted to assess associations between vascular parameters and 18F-FDG PET metabolism in AD-associated brain areas. In the multivariable analysis, only increased age and decreased bT were independently associated with the decline of metabolic activity in AD-associated brain areas (P < 0.001). In the voxel-to-voxel analysis with age as a covariate, bT was strongly associated with the metabolic activity of 40 clusters in AD-associated brain areas (clusters cumulative volume: 63 cm3; T score max: 5.7). In a large age-range population of adult patients, who are still unaffected by neuropsychological disorders, an early reflected arterial pressure wave, as evidenced by a decreased bT value, is strongly associated with hypometabolic activity of AD-associated brain areas, independently of age.

TO STUDY THYROID DYSFUNCTION IN PATIENTS WITH METABOLIC SYNDROME

Background: Metabolic syndrome (MetS) is a cluster of risk factors associated with increased cardiovascular disease and diabetes risk. Thyroid dysfunction (TD), especially hypothyroidism, has been observed more frequently in individuals with MetS. However, the relationship between thyroid function and metabolic syndrome components remains debated. This study aimed to explore the prevalence of thyroid dysfunction and its association with metabolic syndrome components in patients. Methods: A cross-sectional study was conducted at Sri Aurobindo Medical College &amp; P.G. Institute, Indore. A total of 120 patients meeting the International Diabetes Federation (IDF) criteria for metabolic syndrome were included. Detailed history, anthropometric measurements, blood pressure recordings, fasting blood sugar, lipid profile, and thyroid assays were performed. Statistical analysis using SPSS22 and Excel was employed to assess thyroid dysfunction prevalence and its correlation with metabolic syndrome components. Results: Among 120 patients with metabolic syndrome, 28% had thyroid dysfunction. Hypothyroidism was predominant, with subclinical hypothyroidism being the most common type. Females and older individuals (&gt;45 years) showed a higher prevalence of thyroid dysfunction. Patients with thyroid dysfunction exhibited altered metabolic syndrome components, including increased waist circumference, decreased HDL-C, elevated blood pressure, fasting glucose, and triglyceride levels. Conclusion: The study highlights a high prevalence of thyroid dysfunction, especially hypothyroidism, among patients with metabolic syndrome. These findings suggest a potential association between thyroid status and metabolic syndrome components. Screening for thyroid dysfunction in individuals with metabolic syndrome could aid in optimizing clinical management strategies. Further research with larger sample sizes and prospective designs is warranted to explore the impact of thyroid dysfunction management on metabolic syndrome outcomes.

Nocturnal blood pressure dipping and left ventricular hypertrophy among hypertensive outpatients in a Ghanaian hospital.

To investigate the association between the extent of nocturnal systolic blood pressure decline and left ventricular hypertrophy in patients with primary hypertension who were receiving antihypertensive drug therapy. This was a cross-sectional hospital-based study from November 2020 to March 2021. The study was conducted at the Polyclinic of Korle Bu Teaching Hospital, Ghana. Outpatients ≥18 years old with primary hypertension who were receiving antihypertensive drug therapy. Each participant underwent a 24-hour ambulatory blood pressure monitoring and a transthoracic echocardiogram. Left ventricular hypertrophy and the extent of mean systolic blood pressure decline during sleep. 180 participants were recruited, comprising 110 (61.1%) females. The participants' mean (±SD) age was 57.6 ± 11.0 years. 80% had a non-dipping blood pressure pattern, and 43.9% had left ventricular hypertrophy. Uncontrolled office blood pressure was an independent predictor of left ventricular hypertrophy in these patients (AOR 2.010, 95% CI 1.048-3.855, p=0.036); however, a non-dipping nocturnal systolic blood pressure status was not (AOR 1.849, 95% CI 0.850-4.022, p=0.121). 61.1% had abnormal left ventricular geometry, with concentric hypertrophy being the predominant geometric pattern. Left ventricular hypertrophy and non-dipping nocturnal blood pressure were common in these hypertensive Ghanaian patients on antihypertensive therapy. Left ventricular hypertrophy was associated with uncontrolled office blood pressure but not the extent of nocturnal systolic blood pressure declines during a single 24-hour ambulatory blood pressure recording. None declared.

Prevalence of autonomic dysreflexia during spinal cord stimulation after spinal cord injury.

Over the past decade, clinical trials have shown that spinal cord stimulation can restore motor functions that were thought to be permanently impaired in persons with spinal cord injury. However, the off-target effects of delivering electrical impulses to intertwined spinal networks remain largely unknown. This generates safety concerns for this otherwise fast-progressing technology. Herein, we present the prevalence of autonomic dysreflexia (AD) that occurred during implanted spinal cord stimulation testing for motor activation of the lower extremities. Eleven participants with spinal cord injury underwent implantation of temporary percutaneous epidural and dorsal root ganglia stimulation leads. Participants completed two days of parameter testing at baseline, then six days of motor rehabilitation sessions, and two days of parameter testing at end of study. The goal of parameter testing was to determine electrode configuration(s), pulse amplitudes, and frequencies that activated lumbosacral spinal sensorimotor networks that generate lower extremity functions. During all parameter testing sessions, continuous blood pressure and heart rate monitoring recordings were collected. Evidence of autonomic dysreflexia was found in 22% of all parameter tests with participants at rest. Most of these episodes (97%) were asymptomatic. These episodes occurred more frequently when using epidural stimulation, at or near amplitudes that elicited whole leg muscle activation and using a wide-field electrode configuration. Although monitoring occurred during passive testing, motor rehabilitation sessions use stimulation for longer periods, at higher frequencies and amplitudes. These sessions may carry additional risks of autonomic dysreflexia. Investigation of these concerns should continue as spinal cord stimulation progresses toward clinical translation.NEW & NOTEWORTHY Spinal cord stimulation for motor recovery after spinal cord injury is a popular research intervention, though off-target effects are a concern. Using continual blood pressure and heart rate recordings during passive spinal cord stimulation parameter testing, we identified frequent episodes of autonomic dysreflexia that were rarely associated with symptoms. This presents a previously unrecognized risk of spinal cord stimulation and appropriate vigilance in targeted monitoring is urged to maintain participant safety.

Arctic and Southern Ocean polar sea level maps and along-tracks from multi-mission satellite altimetry from 2011 to 2021

Polar sea surface height observation by radar altimeters requires missions with high-latitude orbit and specific processing to observe the sea-ice-covered region within fractures in the ice. Here, we combine sea surface height estimates from different radar satellites over the ice-free and ice-covered polar oceans to create cross-calibrated along-tracks and gridded products over the Arctic Ocean (2011–2021) and the Southern Ocean (2013–2021). The sea surface height from our regional polar products is in great agreement with tide gauges and bottom pressure recorders at monthly timescales in seasonally to year-round ice-covered regions. Thanks to the use of several missions and the mapping strategy, our multi-mission products have a greater resolution than mono-mission products. Part of the sea level variability of the Arctic Ocean product is related to the Arctic Oscillation atmospheric circulation. At long term, the Arctic altimetry sea level is coherent with in-situ steric height evolution in the Beaufort gyre, and negative sea level trends over the 10-year period are observed in the East Siberian slope region, which may be related to the local freshwater decrease observed by other studies. Our regional polar sea level products are limited by current understanding of the sea-ice lead measurements, and homogenization of these polar products with global sea level products needs to be tackled.

Post-insufflation diaphragm contractions in patients receiving various modes of mechanical ventilation

BackgroundDuring mechanical ventilation, post-insufflation diaphragm contractions (PIDCs) are non-physiologic and could be injurious. PIDCs could be frequent during reverse-triggering, where diaphragm contractions follow the ventilator rhythm. Whether PIDCs happens with different modes of assisted ventilation is unknown. In mechanically ventilated patients with hypoxemic respiratory failure, we aimed to examine whether PIDCs are associated with ventilator settings, patients’ characteristics or both.MethodsOne-hour recordings of diaphragm electromyography (EAdi), airway pressure and flow were collected once per day for up to five days from intubation until full recovery of diaphragm activity or death. Each breath was classified as mandatory (without-reverse-triggering), reverse-triggering, or patient triggered. Reverse triggering was further subclassified according to EAdi timing relative to ventilator cycle or reverse triggering leading to breath-stacking. EAdi timing (onset, offset), peak and neural inspiratory time (Tineuro) were measured breath-by-breath and compared to the ventilator expiratory time. A multivariable logistic regression model was used to investigate factors independently associated with PIDCs, including EAdi timing, amplitude, Tineuro, ventilator settings and APACHE II.ResultsForty-seven patients (median[25%-75%IQR] age: 63[52–77] years, BMI: 24.9[22.9–33.7] kg/m2, 49% male, APACHE II: 21[19–28]) contributed 2 ± 1 recordings each, totaling 183,962 breaths. PIDCs occurred in 74% of reverse-triggering, 27% of pressure support breaths, 21% of assist-control breaths, 5% of Neurally Adjusted Ventilatory Assist (NAVA) breaths. PIDCs were associated with higher EAdi peak (odds ratio [OR][95%CI] 1.01[1.01;1.01], longer Tineuro (OR 37.59[34.50;40.98]), shorter ventilator inspiratory time (OR 0.27[0.24;0.30]), high peak inspiratory flow (OR 0.22[0.20;0.26]), and small tidal volumes (OR 0.31[0.25;0.37]) (all P ≤ 0.008). NAVA was associated with absence of PIDCs (OR 0.03[0.02;0.03]; P < 0.001). Reverse triggering was characterized by lower EAdi peak than breaths triggered under pressure support and associated with small tidal volume and shorter set inspiratory time than breaths triggered under assist-control (all P < 0.05). Reverse triggering leading to breath stacking was characterized by higher peak EAdi and longer Tineuro and associated with small tidal volumes compared to all other reverse-triggering phenotypes (all P < 0.05).ConclusionsIn critically ill mechanically ventilated patients, PIDCs and reverse triggering phenotypes were associated with potentially modifiable factors, including ventilator settings. Proportional modes like NAVA represent a solution abolishing PIDCs.

Metabolic Adaptation in Epilepsy: From Acute Response to Chronic Impairment.

Epilepsy is characterized by hypersynchronous neuronal discharges, which are associated with an increased cerebral metabolic rate of oxygen and ATP demand. Uncontrolled seizure activity (status epilepticus) results in mitochondrial exhaustion and ATP depletion, which potentially generate energy mismatch and neuronal loss. Many cells can adapt to increased energy demand by increasing metabolic capacities. However, acute metabolic adaptation during epileptic activity and its relationship to chronic epilepsy remains poorly understood. We elicited seizure-like events (SLEs) in an in vitro model of status epilepticus for eight hours. Electrophysiological recording and tissue oxygen partial pressure recordings were performed. After eight hours of ongoing SLEs, we used proteomics-based kinetic modeling to evaluate changes in metabolic capacities. We compared our findings regarding acute metabolic adaptation to published proteomic and transcriptomic data from chronic epilepsy patients. Epileptic tissue acutely responded to uninterrupted SLEs by upregulating ATP production capacity. This was achieved by a coordinated increase in the abundance of proteins from the respiratory chain and oxidative phosphorylation system. In contrast, chronic epileptic tissue shows a 25-40% decrease in ATP production capacity. In summary, our study reveals that epilepsy leads to dynamic metabolic changes. Acute epileptic activity boosts ATP production, while chronic epilepsy reduces it significantly.

P098 CARDIAC REMODELING IN MICE TREATED WITH SODIUM OXALATE AND AORTIC STENOSIS

Background: Cardiovascular Diseases are one of the main global public health problems, with increasing mortality due to population aging and Hypertension (HTN). HTN is a risk factor for other diseases, such as aortic stenosis, renal dysfunction, and cardiac hypertrophy (CH). The hemodynamic overload caused by HTN affects the heart and kidneys, but the exact mechanisms of these alterations are not fully understood. Experimental models help study these mechanisms; however, a well-established model of CH with cardiorenal dysfunction does not yet exist. Objective: to evaluate whether the combination of cardiac hypertrophy, induced by transverse aortic constriction (TAC), and renal injury, induced by soluble sodium oxalate (OXA), can be a new model of CH with cardiorenal dysfunction. Methods: Male C57BL mice were randomized as follows: SHAM, receiving saline or OXA solution, and TAC, receiving saline or OXA solution. Echocardiography, direct blood pressure (BP) recording, metabolic cage, histology were performed to evaluate cardiac and renal function, hemodynamics, autonomic modulation, and baroreflex. Results: The TAC+OXA group showed the highest systolic BP(SBP) (SBP: SHAM: 122±5.24 vs. TAC+OXA: 160±5.24 mmHg, p&lt;0.01), increased double product (DP) (DP: SHAM: 64.65±4.76 mmHg/bpm vs. TAC: 89.53±5.85 mmHg/bpm, p=0.02), significant reduction in autonomic modulation (RMSSD: OXA: 12.5±1.8 vs. TAC+OXA: 2.8±0.2 ms, p&lt;0.01) and reflex tachycardia, eccentric hypertrophy, and worse renal function. The TAC group showed eccentric hypertrophy, increased BP variability (SD-SBP: SHAM: 2.97±0.07 mmHg vs. TAC: 5.63±0.57 mmHg, p≤0.01), diastolic dysfunction, and dilated left ventricle in diastole. The OXA group showed increased autonomic modulation and heart rate variability, renal damage characterized by inflammation, proximal tubule damage, and interstitial fibrosis when associated with TAC. All treated groups showed a significant reduction in reflex tachycardia. Conclusion: Transverse aortic constriction combined with OXA gavage is a model of CH with renal dysfunction, as the combination caused more significant renal damage, systemic hypertension, decreased autonomic modulation and baroreflex sensitivity, and eccentric hypertrophy with subsequent LV diastolic dysfunction.

P214 PREDICTION OF AMBULATORY BRACHIAL CUFF-BASED OSCILLOMETRIC PULSE WAVE VELOCITY USING A NOVEL METHOD FOR ESTIMATING TOTAL ARTERIAL COMPLIANCE

Background and Objective: Total arterial compliance (Ct) serves as a critical determinant of arterial hemodynamics, providing insights into the mechanical and structural characteristics of large arteries and influencing ventricular-arterial coupling. To estimate Ct, we developed a method utilizing data from 24-hour ambulatory blood pressure monitoring (24-h ABPM) recordings. Our objective is to evaluate the reliability of Ct in estimating oscillometric pulse wave velocity (oPWV), with the potential to eliminate the requirement for additional oPWV measurements. Methods: A cross-sectional study was conducted, involving 162 patients who underwent 24-h ABPM, resulting in a total of 8,113 blood pressure (BP) recordings. oPWV was measured during 24-h ABPM using a Custo Screen 310 device (Custo, Ottobrunn, Germany), which has been validated. Ct was estimated employing a two-element Windkessel model based on mean systolic pressure. The formula utilized for Ct estimation was Ct/BSA= (38/PPth)×(4/5)×(Td/T)-(3/7), where BSA denotes body surface area, Td represents diastolic time, T signifies the cardiac period, and PPth denotes theoretical pulse pressure. A linear regression model (LRM) was developed to estimate oPWV from Ct. Results: Among the participants, 55.1% were men, with an average age of 55.7±16.2 years and a body mass index of 27.4±3.7 kg/m2. The analyzed records revealed an average systolic blood pressure of 125.6±18.7 mmHg, diastolic blood pressure of 79.5±12.2 mmHg, heart rate of 71.0±12.2 beats per minute, Ct of 0.9±0.3 mL/mmHg, and oPWV of 7.2±1.8 m/s. The best predictive model (R2=0.42; r=0.65) for oPWV was based on the ratio of systolic time (Ts) to Ct as follows: oPWV=3.3 × 6.0 ×[Ts/(Ct/BSA)]. Indexed Ct demonstrated an inverse relationship with oPWV (Figure). Residuals analysis confirmed compliance with assumptions. Conclusions: The Ts/Ct ratio inversely predicts oPWV, indicating an inverse relationship between Ct and oPWV in this population. These findings suggest that estimated Ct has the potential to replace oPWV in clinical practice for cardiovascular risk stratification.

Abstract P175: The Effect of TRF on Hypertension Development in Male Dahl Salt-Sensitive Rats

Time restricted feeding (TRF), or food consumption restricted to &lt;10 hrs/day, has been shown to improve blood pressure in various cardiometabolic diseases, yet there is limited data on the effect in SS hypertension. The goal of this study was to examine the effect of TRF on disease development in the Dahl SS rat. We hypothesized that implementing TRF during a critical timepoint in disease progression would reduce mean arterial blood pressure (MAP). To study this, femoral catheters were surgically implanted in male Dahl SS rats at 9±0.5 weeks of age (n=5-7/group), allowing for urine and arterial blood sample collection from conscious rats during continual blood pressure recording. After 1 week of recovery, rats either continued a low salt (LS;0.4% NaCl) diet or were switched to a high salt diet (HS;4% NaCl) with ad libitum (ad lib) access for 1 week. At the start of week 2, a subset of rats began TRF, in which food was provided for 8 hrs (10PM-6AM) during their active period for an additional week. Rats meeting the following criteria were included in analysis: pulse pressure &gt; 10 mmHg, baseline MAP of 115-130 mmHg, and a 10-20 mmHg increase in MAP after 1 week on HS. Differences in MAP were analyzed by 2-way ANOVA with Tukey multiple comparisons and data are reported as mean ± SEM. By the end of week 2, HS TRF rats trended toward lower average MAP compared to HS ad lib rats (141.51±3.41 vs 149.49±1.65 mmHg; p=0.07). However, we found that the HS TRF rats had reduced MAP during their active period (6PM-6AM), compared to the HS ad lib rats (142.60±2.99 vs 151.65±1.862 mmHg; p&lt;0.05), but no difference during the inactive period (6AM-6PM). At the end of the study, average MAP was calculated every 4 hrs to identify the timing at which TRF reduced MAP. We found that the HS TRF rats had lower MAP from 6PM to 10PM (134.61±2.34 vs 146.75±1.21 mmHg; p&lt;0.05) and 10PM to 2AM (144.58±2.79 vs 154.70±2.18 mmHg; p&lt;0.05) when compared to the HS ad lib rats. The LS TRF group also had lower pressure from 6PM-10PM compared to the LS ad lib group (124.93±1.19 vs 130.56±0.73 mmHg; p&lt;0.05), suggesting that this time-specific reduction in MAP may be due to fasting, as there were no other differences in MAP within the LS groups. This suggests that TRF may slow progression of hypertension development in the Dahl SS rat, primarily by affecting MAP during the active period. Future studies will examine how TRF affects Na + handling to further understand these time-dependent effects.

Blood pressure control in Türkiye: A primary healthcare pilot study

Hypertension is present in almost a third of Türkiye’s adult population. The Ministry of Health of the Republic of Türkiye in conjunction with the World Health Organization, rolled out a pilot primary health care model from February 2019 to 2020 to improve hypertension screening, management, and follow-up across the provinces of Erzincan, Çankırı and Uşak. The model was conducted in selected family health centers for one year and included multiple interventions – training of multidisciplinary primary care teams, implementation of evidence-based, standardised clinical guidelines related to monitoring and treatment of hypertension, clinical supervision and performance monitoring, and provision of health education to hypertensive individuals. Repeat surveys of population-based random samples of 975 patients were taken before (December 2018) and after (February 2020) model implementation to evaluate its effect on care delivery. There was an almost 6.5-fold increase in the measurement and subsequent recording of blood pressure compared to before model implementation (from 50 to 323). Blood pressure control improved to 58 % of measured individuals compared to 46 % of those measured at initial evaluation. The frequency of measuring risk factors and outcomes related to hypertension at least once a year increased for creatinine from 71 % to 79 %, fasting blood glucose from 70 % to 78 %, and tobacco use from 22 % to 31 %. Prescription of antihypertensive drugs increased from 49 % to 61 %. With improvements in hypertension-related care in all measures and across all regions, this primary healthcare model represents a potential paradigm for nationwide implementation.

Association of Wearable Device-Measured Step Volume and Variability With Blood Pressure in Older Chinese Adults: Mobile-Based Longitudinal Observational Study.

The paucity of evidence on longitudinal and consecutive recordings of physical activity (PA) and blood pressure (BP) under real-life conditions and their relationships is a vital research gap that needs to be addressed. This study aims to (1) investigate the short-term relationship between device-measured step volume and BP; (2) explore the joint effects of step volume and variability on BP; and (3) examine whether the association patterns between PA and BP varied across sex, hypertension status, and chronic condition status. This study used PA data of a prospective cohort of 3070 community-dwelling older adults derived from a mobile health app. Daily step counts, as a proxy of step volume, were derived from wearable devices between 2018 and 2022 and categorized into tertiles (low, medium, and high). Step variability was assessed using the SD of daily step counts. Consecutive daily step count recordings within 0 to 6 days preceding each BP measurement were analyzed. Generalized estimation equation models were used to estimate the individual and joint associations of daily step volume and variability with BP. Stratified analyses by sex, the presence of hypertension, and the number of morbidities were further conducted. A total of 3070 participants, with a median age of 72 (IQR 67-77) years and 71.37% (2191/3070) women, were included. Participants walked a median of 7580 (IQR 4972-10,653) steps and 5523 (IQR 3590-7820) meters per day for a total of 592,597 person-days of PA monitoring. Our results showed that higher levels of daily step volume were associated with lower BP (systolic BP, diastolic BP, mean arterial pressure, and pulse pressure). Compared with participants with low step volume (daily step counts <6000/d) and irregular steps, participants with high step volume (≥9500/d) and regular steps showed the strongest decrease in systolic BP (-1.69 mm Hg, 95% CI -2.2 to -1.18), while participants with medium step volume (6000/d to <9500/d) and regular steps were associated with the lowest diastolic BP (-1.067 mm Hg, 95% CI -1.379 to -0.755). Subgroup analyses indicated generally greater effects on women, individuals with normal BP, and those with only 1 chronic disease, but the effect pattern was varied and heterogeneous between participants with different characteristics. Increased step volume demonstrated a substantial protective effect on BP among older adults with chronic conditions. Furthermore, the beneficial association between step volume and BP was enhanced by regular steps, suggesting potential synergistic protective effects of both increased step volume and step regularity. Targeting both step volume and variability through PA interventions may yield greater benefits in BP control, particularly among participants with hypertension and a higher chronic disease burden.