Invasive Measurements Research Articles

The clinical value of noninvasive left ventricular myocardial work in the diagnosis of myocardial ischemia in coronary heart disease: a comparative study with coronary flow reserve fraction.

The prompt and precise identification of hemodynamically significant coronary artery lesions remains an ongoing challenge. This study investigated the diagnostic value of non-invasive global left ventricular myocardial work indices by echocardiography in functional status of coronary artery disease (CAD) patients with myocardial ischemia using fractional flow reserve (FFR) as the gold standard. A total of 77 consecutive patients with clinically suspected CAD were prospectively enrolled. All participants sequentially underwent echocardiography, invasive coronary angiography (ICA) and FFR measurement. According to the results of ICA, patients were divided into myocardial ischemia group (FFR ≤ 0.8, n = 27) and non-myocardial ischemia group (FFR > 0.8, n = 50). Myocardial work indices including global work index (GWI), global constructive work (GCW), global wasted work (GWW), global work efficiency (GWE), global positive work (GPW), global negative work (GNW), global systolic constructive work (GSCW) and global systolic wasted work (GSWW) were obtained by using the non-invasive left ventricular pressure strain loop (PSL) technique. Compared with the non-myocardial ischemia group, GWI, GCW, GPW and GSCW were significantly decreased in the myocardial ischemia group at either the 18-segment level or the 12-segment level (P < 0.001). At the 18-segment level, GWI < 1783.6 mmHg%, GCW < 1945.4 mmHg%, GPW < 1788.7 mmHg% and GSCW < 1916.5 mmHg% were optimal cut-off value to detect myocardial ischemia with an FFR ≤ 0.8. Global left ventricular myocardial work indices by echocardiography exhibited a good diagnostic value in patients with CAD and may have a good clinical significance for the screening of suspected myocardial ischemia.

Abstract Mo103: Aberrant Trans- and De- Nitrosylation Underpins Nitrosative Stress in Cardiometabolic HFpEF

Background: Heart failure with preserved ejection fraction (HFpEF) is among the leading causes of cardiovascular mortality and morbidity. Recent reports suggest excessive myocardial protein S-nitrosylation (-SNO), a hallmark of nitrosative stress, contributes to HFpEF pathophysiology. However, the role of transnitrosylases, enzymes that induce protein-SNO, or denitrosylases, enzymes that eliminate protein-SNO, have not been investigated in the context of HFpEF. Research Questions and Goals: We sought to investigate the regulation of protein nitrosylation dynamics in a rat model of cardiometabolic HFpEF. Methods: Echocardiographic assessment, invasive hemodynamic measurements, and exercise testing were conducted in WKY or ZSF1 obese (Ob) rats to evaluate HFpEF severity. Nitric oxide (NO) bioavailability and protein-SNO levels were determined in the heart tissue. Endothelial-dependent vascular reactivity was assayed to further evaluate NO signaling. In parallel, single-cell (sc) RNA sequencing was performed to determine the transcriptional changes in trans- and denitrosylases, as well as NO synthases. Results: We observed progressive deterioration in LV diastolic function (significantly elevated E/e’ and LV end-diastolic pressure) and exercise performance in ZSF1 Ob when compared to WKY controls. Notably, ZSF1 Ob rats exhibited an age-dependent elevation in protein-SNO levels, despite significant reduction in NO bioavailability and signaling. Targeted sc transcriptomic analysis revealed significantly elevated expression of transnitrosylases such as hemoglobin subunit α and β in cardiomyocytes, endothelial cells, and cardiac fibroblasts from ZSF1 Ob hearts. In contrast, significantly reduced expression of denitrosylases such as thioredoxin 2 was found in the ZSF1 Ob cardiomyocytes. No change was observed in expression of NO synthases (nNOS, iNOS, eNOS). Conclusion: Herein, we demonstrate a profound disconnect between insufficient NO bioavailability and nitrosative stress in ZSF1 Ob rat model of HFpEF. Our data suggests the pathological accumulation of nitroso - proteins, may be attributed in part to the derangement of transnitrosylases and denitrosylases expression. Restoration of physiological protein nitrosylation dynamics may represent a novel therapeutic approach for HFpEF, and warrants further investigation.

OT Enhanced: Cupping’s Unique Impact on Conservative Carpal Tunnel Treatment

Abstract Date Presented 03/22/24 A statistically significant association between cupping therapy and increased protective sensation in the hand was observed. The results support the use of conservative therapies for treating carpal tunnel syndrome compared with invasive measures. Primary Author and Speaker: Abbigail Walsh Additional Authors and Speakers: Aubrey Bealer, Lee Bryant, Emily Giordano Contributing Authors: Kristopher Matullo, Ann Potter

Sex-dependent remodeling of right ventricular function in a rat model of pulmonary arterial hypertension.

Right ventricular (RV) function is an important prognostic indicator for pulmonary arterial hypertension (PAH), a vasculopathy that primarily and disproportionally affects women with distinct pre- and postmenopausal clinical outcomes. However, most animal studies have overlooked the impact of sex and ovarian hormones on RV remodeling in PAH. Here, we combined invasive measurements of RV hemodynamics and morphology with computational models of RV biomechanics in sugen-hypoxia (SuHx)-treated male, ovary-intact female, and ovariectomized female rats. Despite similar pressure overload levels, SuHx induced increases in end-diastolic elastance and passive myocardial stiffening, notably in male SuHx animals, corresponding to elevated diastolic intracellular calcium. Increases in end-systolic chamber elastance were largely explained by myocardial hypertrophy in male and ovary-intact female rats, whereas ovariectomized females exhibited contractility recruitment via calcium transient augmentation. Ovary-intact female rats primarily responded with hypertrophy, showing fewer myocardial mechanical alterations and less stiffening. These findings highlight sex-related RV remodeling differences in rats, affecting systolic and diastolic RV function in PAH.NEW & NOTEWORTHY Combining hemodynamic and morphological measurements from male, female, and ovariectomized female pulmonary arterial hypertension (PAH) rats revealed distinct adaptation mechanisms despite similar pressure overload. Males showed the most diastolic stiffening. Ovariectomized females had enhanced myocyte contractility and calcium transient upregulation. Ovary-intact females primarily responded with hypertrophy, experiencing milder passive myocardial stiffening and no changes in myocyte shortening. These findings suggest potential sex-specific pathways in right ventricular (RV) adaptation to PAH, with implications for targeted interventions.

Label-Free Single-Cell Cancer Classification from the Spatial Distribution of Adhesion Contact Kinetics.

There is an increasing need for simple-to-use, noninvasive, and rapid tools to identify and separate various cell types or subtypes at the single-cell level with sufficient throughput. Often, the selection of cells based on their direct biological activity would be advantageous. These steps are critical in immune therapy, regenerative medicine, cancer diagnostics, and effective treatment. Today, live cell selection procedures incorporate some kind of biomolecular labeling or other invasive measures, which may impact cellular functionality or cause damage to the cells. In this study, we first introduce a highly accurate single-cell segmentation methodology by combining the high spatial resolution of a phase-contrast microscope with the adhesion kinetic recording capability of a resonant waveguide grating (RWG) biosensor. We present a classification workflow that incorporates the semiautomatic separation and classification of single cells from the measurement data captured by an RWG-based biosensor for adhesion kinetics data and a phase-contrast microscope for highly accurate spatial resolution. The methodology was tested with one healthy and six cancer cell types recorded with two functionalized coatings. The data set contains over 5000 single-cell samples for each surface and over 12,000 samples in total. We compare and evaluate the classification using these two types of surfaces (fibronectin and noncoated) with different segmentation strategies and measurement timespans applied to our classifiers. The overall classification performance reached nearly 95% with the best models showing that our proof-of-concept methodology could be adapted for real-life automatic diagnostics use cases. The label-free measurement technique has no impact on cellular functionality, directly measures cellular activity, and can be easily tuned to a specific application by varying the sensor coating. These features make it suitable for applications requiring further processing of selected cells.

Microscopic Temperature Sensor Based on End-Face Fiber-Optic Fabry–Perot Interferometer

This work proposes a simple and affordable technology for the manufacturing of a miniature end-face fiber-optic temperature sensor based on a Fabry–Perot interferometer formed from a transparent UV-curable resin. For the manufactured working prototype of the sensor, the sensitivity and operating temperature range were determined, and the methods for their enhancement were proposed. Due to its small size, the proposed type of sensor can be used in high-precision and minimally invasive temperature measurements, in biology for microscale sample monitoring, and in medicine during operations using high-power lasers. A microwave photonic method is proposed that enables the interrogation of the sensor without using an optical spectrum analyzer.

Determinants of invasive left atrial pressure in patients with atrial fibrillation.

Estimation of left ventricular (LV) filling pressures in patients with atrial fibrillation (AF) is challenging due to lack of reliable parameters. This study investigates the association between cardiac structure and function and invasive mean left atrial pressure (LAP). This is a multi-center prospective study enrolling patients undergoing transcatheter ablation for AF. The invasive measurement of LAP was performed at the time of the procedure while the echocardiography within the previous 24 hours. A mean LAP ≥ 15 mmHg was considered as increased. Overall, 101 patients were included (mean age 65.8 ± 8.5 years, 68% male, mean LV ejection fraction 56.6 ± 8.0%). No significant differences regarding clinical characteristics were detected between the group of patients with normal (n=47) or increased LAP (n=54). The latter showed lower values of LV global longitudinal strain, larger left atrial volumes (LAV) and worse right ventricular (RV) function. After multivariable adjustment, higher E/e' ratio (p=0.041) and minimal LAV index (LAVI min) (p=0.031), lower peak atrial longitudinal strain (PALS) (p=0.030) and RV free wall strain (p=0.037), but not maximal LAV index (LAVI max) (p=0.137), were significantly associated with mean LAP. The associations were not modified by cardiac rhythm. Overall, LAVI min showed the best diagnostic accuracy to predict elevated LAP (AUC 0.703). LA structure and function assessment well correlates with mean LAP in patients with AF. These measures may be used in the assessment of filling pressure in these patients.

Comparison of continuous temperature measurement methods in the intensive care unit: standard bladder catheter measurements versus non-invasive transcutaneous sensors.

The purpose of this study was to compare a wearable system for body core temperature measurement versus bladder and tympanic thermometers in an intensive care setting. The question was, if continuous non-invasive sensors in the intensive care unit represent an alternative to current standard methods of invasive continuous bladder temperature measurement methods?Between May and September 2023, a comparative investigation involving 112 patients was conducted in a 20-bed surgical intensive care unit to assess various temperature probes, including those placed in the tympanic tube, bladder, and skin. To achieve this, a wireless non-invasive sensor system provided by greenTEG AG, Switzerland, was affixed to different body locations (clavicular and lateral chest) of each catheterized patient (equipped with a temperature probe) admitted to the intensive care unit. Furthermore, tympanic temperatures were recorded at specified intervals. The measurement duration ranged from a minimum of six hours to a maximum of six days, resulting in the analysis of a total of 355 simultaneous temperature measurements.In this study, a wearable temperature measurement system attached to two different body sites revealed a consistent negative bias compared to bladder temperature. In addition, the measurements were particularly influenced by body constitution. The tested system in all patients showed a mean absolute error (MAE) of 0.45°C for the lateral chest and 0.50°C for the clavicular position. Tympanic measurements had a mean absolute error of 0.35°C. In patients with body mass index (BMI) ≥ 25 the MAE increased to 0.5°C for the lateral chest and 0.56°C for the clavicular position. In contrast, the tympanic measurement had a reduced MAE of 0.32°C, which is well below this threshold when compared to bladder measurements.In conclusion the investigated system did not meet the clinically relevant acceptance criteria and showed low precision in correctly identifying fever episodes compared to invasive temperature probes, however its main advantage lies in its continuity and non-invasiveness. This makes it a potential alternative to intermittent tympanic measurement devices. In this study we were able to show, that in at least one subset of patients, the non-invasive and continuous device demonstrated a precision comparable to tympanic measurements.The accuracy of all non-invasive methods was lower than in previous studies, suggesting that the use of bladder temperature as reference and user related variations may have introduced additional errors.

Assessing Leg Blood Flow and Cardiac Output During Running Using Thermodilution.

Cardiac output (Q̇C) and leg blood flow (Q̇LEG) can be measured simultaneously with high accuracy using transpulmonary and femoral vein thermodilution with a single-bolus injection. The invasive measure has offered important insight into leg hemodynamics and blood flow distribution during exercise. Despite being the natural modality of exercise in humans, there has been no direct measure of Q̇LEG while running in humans. We sought to determine the feasibility of the thermodilution technique for measuring Q̇LEG and conductance during high-intensity running, in an exploratory case study. A trained runner (30 years male) completed two maximal incremental tests on a cycle ergometer and motorized treadmill. Q̇LEG and Q̇C were determined using the single-bolus thermodilution technique. Arterial and venous blood were sampled throughout exercise, with continuous monitoring of metabolism, intra-arterial and venous pressure, and temperature. The participant reached a greater peak oxygen uptake (V̇O2peak) during running relative to cycling (74 vs. 68 mL/kg/min) with comparable Q̇LEG (19.0 vs. 19.5 L/min) and Q̇C (27.4 vs. 26.2 L/min). Leg vascular conductance was greater during high-intensity running relative to cycling (82 vs. 70 mL/min/mmHg @ ~80% V̇O2peak). The "beat phenomenon" was apparent in femoral flow while running, producing large gradients in conductance (62-90 mL/min/mmHg @ 70% V̇O2peak). In summary, we present the first direct measure of Q̇LEG and conductance in a running human. Our findings corroborate several assumptions about Q̇LEG during running compared with cycling. Importantly, we demonstrate that using thermodilution in running exercise can be completed effectively and safely.

Rapid alleviation of perioperative airway obstruction through positional adjustments in a patient with a giant anterior mediastinal mass: A case report

Rationale: This case describes the rapid resolution of acute airway obstruction after anesthesia induction in a young man with a massive 12.7 × 9 × 12 cm anterior mediastinal tumor. It emphasizes the remarkable effectiveness of positional adjustments in immediately alleviating airway compression caused by large mediastinal masses. The crisis was resolved quickly and without invasive measures through only positional tactics, without the need for emergency invasive interventions. This highlights the decisive role of strategic patient positioning as a primary technique for perioperative management of mediastinal masses, ensuring adequate ventilation and preventing catastrophic outcomes. Patient concerns: Due to the unique anatomical location of mediastinal tumors, the anesthesia risks for patients with mediastinal tumors are very high. These tumors can cause airway compression, leading to severe cardiovascular dysfunction and even mortality during general anesthesia. Diagnoses: Combining the patient’s medical history, symptoms and signs, fiberoptic bronchoscopy and excluding other causes, it was confirmed that the tumor compressed the airway and blocked the airway. Interventions: Ventilation was rapidly improved by adjusting the patient’s position, ultimately to the left lateral decubitus position with head-up tilt. Outcomes: Through positional adjustment, the patient’s airway obstruction symptoms rapidly improved. Airway pressure decreased significantly, end-tidal carbon dioxide returned to 40 mm Hg, and oxygen saturation increased to 95%. The mediastinal tumor was ultimately successfully resected. The surgical procedure went smoothly with successful extubation on the first postoperative day. The patient had a smooth recovery and was discharged on the seventh postoperative day without any lingering postoperative complications. Lessons: This case provides an important educational illustration of how mediastinal mass patients can develop sudden catastrophic airway obstruction after induction despite being asymptomatic preoperatively. It demonstrates an effective crisis rescue technique through positioning that may help inform management of similar high-risk cases.

Right atrial and right ventricular strain: prognostic value depends on the severity of tricuspid regurgitation.

Assessing right heart function is challenging, particularly when significant tricuspid regurgitation (TR) is present. Among available echocardiographic techniques for assessment, literatures suggests that strain imaging may be more reliable and less susceptible to loading conditions. Thus, we aimed to assess the validity of RA and RV strain relative to conventional metrics as well as their utility in predicting patient outcomes in TR. We studied 262 consecutive patients (mean age 74 ± 11.2 years, 53% male) who underwent same-day echocardiography and right heart catheterization between 2018 and 2023. We compared right heart strain to traditional metrics of RV function and subsequently correlated RA and RV strain to heart failure (HF)-related death or hospitalization, whichever came first. Over a mean follow-up of 34 ± 15 months, there were 103 deaths and HF hospitalizations. Both RA and RV strain were correlated with echocardiographic and invasive measures of right heart function. Across all patients, preserved RA strain was associated with lower risk of adverse outcomes (HR 0.763, 95% CI 0.618-0.943). Similarly, preserved RV strain was correlated with better outcomes, though this was only statistically significant in patients without severe TR or pulmonary hypertension (HR 2.450, 95% CI 1.244-4.825). Moreover, abnormal ratios of RV strain to pulmonary pressures and RV size were significantly correlated with adverse outcomes (p < 0.05 each). RA and RV strain are independently correlated with echocardiographic and invasive measures of cardiac function. Moreover, preserved RA and RV strain are likely associated with better clinical outcomes.

Independent Factors Influencing Changes in Baroreceptor Sensitivity after Carotid Endarterectomy

ObjectiveCarotid endarterectomy (CEA) is a well-established standard therapy for patients with symptomatic or asymptomatic high-grade carotid stenosis. The aim of carotid endarterectomy is to decrease the risk of stroke and avoid relevant functional loss. However, carotid endarterectomy is known to be associated with haemodynamic dysregulation. In this study we compared eversion CEA (E-CEA) and conventional CEA (C-CEA) regarding postoperative blood pressure values as well as preoperative and postoperative baroreceptor sensitivity in the first 7 days after surgery. The aim was to find possible factors influencing changes in baroreceptor sensitivity. MethodsPatients (111 patients were enrolled, of which 50 patients received C-CEA and 61 patients E-CEA) were prospectively enrolled in this study. For the measurement of baroreceptor sensitivity, a non-invasive Finometer measuring device from Finapres Medical System B.V. (Amsterdam, The Netherlands) was used. Measurements were performed one day before surgery (PRE), directly after surgery (F1), on day 1 (F2), day 2 (F3) and on day 7 (F4) postoperatively. ResultsPostoperative blood pressure values were significantly higher in the E-CEA group on the day of surgery (F1) (p<0.001) and on day 1 (F2) (p<0.001). From day 2 (F3, F4) postoperatively, no significant difference was found between the two groups. The invasive blood pressure measurement in the postoperative recovery room showed significantly higher systolic blood pressure values in the E-CEA group (p=0.001). The need of acute antihypertensive therapy was significantly higher in the recovery room in the E-CEA group (p=0.020). With regard to changes in baroreceptor sensitivity, significantly lower baroreceptor sensitivity (BRS) values were recorded in the E-CEA group at 1 day (F2) postoperatively (p=0.005). The regression analysis showed that the applied surgical technique and the patients age were significant factors influencing changes in baroreceptor sensitivity. ConclusionsIn this study we could confirm higher blood pressure levels after E-CEA in the first two days after surgery. Additionally, we identified two factors possibly influencing baroreceptor sensitivity: surgical technique and age. Based on the data obtained in this study, haemodynamic dysregulation after CEA (E-CEA, C-CEA) is temporary and short-term. Already after the second postoperative day there was no significant difference between the E-CEA and E-CEA groups, this effect remained stable after 7 days.

Influence of the pressure wire on the fractional flow reserve calculation: CFD analysis of an ideal vessel and clinical patients with stenosis

Background and objectiveFractional Flow Reserve (FFR) is generally considered the gold standard in hemodynamics to assess the impact of a stenosis on the blood flow. The standard procedure to measure involves the displacement of a pressure guide along the circulatory system until it is placed next to the lesion to be analyzed. The main objective of the present study is to analyze the influence of the pressure guide on the invasive FFR measurements and its implications in clinical practice. MethodsWe studied the influence of pressure wires on the measurement of Fractional Flow Reserve (FFR) through a combination of Computational Fluid Dynamics (CFD) simulations using 45 clinical patient data with 58 lesions and ideal geometries. The analysis is conducted considering patients that were subjected to a computer tomography and also have direct measurements using a pressure guide. Influence of the stenosis severity, degree of occlusion and blood viscosity has also been studied. ResultsThe influence of pressure wires specifically affects severe stenosis with a lumen diameter reduction of 50 % or greater. This type of stenosis leads to reduced hyperemic flow and increased coronary pressure drop. Thus, we identified that the placement of wires during FFR measurements results in partial obstruction of the coronary artery lumen, leading to increased pressure drop and subsequent reduction in blood flow. The severity of low FFR values associated with severe stenosis may be prone to overestimation when compared to stenosis without severe narrowing. These results have practical implications, particularly in the interpretation of lesions falling within the “gray zone” (0,75−0,80). ConclusionsThe pressure wire's presence significantly alters the flow on severe lesions, which has an impact on the FFR calculation. In contrast, the impact of the pressure wire appears to be reduced when the FFR is larger than 0.8. The findings provide critical information for physicians, emphasizing the need for cautious interpretation of FFR values, particularly in severe stenosis. It also offers insights into improving the correlation between FFRct models and invasive measurements by incorporating the influence of pressure wires.

Subclavian arterial rupture due to blunt trauma injury: A case report.

Subclavian arterial injury due to blunt trauma is rare but can have devastating outcomes. Massive hemorrhage or limb ischemia might develop depending on the extent of damage, and open repair might be necessary to salvage the limb. However, life-saving treatments should be prioritized in critically unstable patients. A 21-year-old male patient who was transferred to our trauma center following a motorcycle accident. Abdominal and chest computed tomography (CT) revealed right renal injury and massive hemothorax with several rib fractures in the right chest. Right renal injury with multiple extravasations and right 8th intercostal arterial injury were detected during angiography. Emergent exploration with lateral thoracotomy was performed to manage right hemothorax. Pulsating bleeding from the thoracic roof observed in the operative field suggested a subclavian arterial injury. The unstable vital signs did not recover despite massive transfusion, and his right arm had already stiffened. Therefore, endovascular approach was adopted and the second portion of the right subclavian artery was embolized using microcoils and thrombin. Postoperative intensive care unit management performed to resuscitate patient from multiorgan failure included continuous renal replacement therapy (CRRT). After confirming the demarcation lines, transhumeral amputation of the right arm was performed on admission day 12. The patient recovered from multiorgan failure for more than 3 weeks after the accident; however, the patient survived. Limb salvage, albeit critical for quality of life, is not possible in some cases where life-saving measures require its sacrifice. In these cases, quick decision-making by the surgeon is paramount for patient survival. As illustrated in this case, endovascular approaches should be considered less invasive measures to save the patient's life.

Non-invasive fractional flow reserve estimation in coronary arteries using angiographic images

Coronary artery disease is the leading global cause of mortality and Fractional Flow Reserve (FFR) is widely regarded as the gold standard for assessing coronary artery stenosis severity. However, due to the limitations of invasive FFR measurements, there is a pressing need for a highly accurate virtual FFR calculation framework. Additionally, it’s essential to consider local haemodynamic factors such as time-averaged wall shear stress (TAWSS), which play a critical role in advancement of atherosclerosis. This study introduces an innovative FFR computation method that involves creating five patient-specific geometries from two-dimensional coronary angiography images and conducting numerical simulations using computational fluid dynamics with a three-element Windkessel model boundary condition at the outlet to predict haemodynamic distribution. Furthermore, four distinct boundary condition methodologies are applied to each geometry for comprehensive analysis. Several haemodynamic features, including velocity, pressure, TAWSS, and oscillatory shear index are investigated and compared for each case. Results show that models with average boundary conditions can predict FFR values accurately and observed errors between invasive FFR and virtual FFR are found to be less than 5%.

Accuracy of oscillometric noninvasive blood pressure at the ankle in the lateral position during general anesthesia

BackgroundThis study aimed to evaluate the accuracy of ankle blood pressure measurements in relation to invasive blood pressure in the lateral position.MethodsThis prospective observational study included adult patients scheduled for elective non-cardiac surgery under general anesthesia in the lateral position. Paired radial artery invasive and ankle noninvasive blood pressure readings were recorded in the lateral position using GE Carescape B650 monitor. The primary outcome was the ability of ankle mean arterial pressure (MAP) to detect hypotension (MAP < 70 mmHg) using area under the receiver operating characteristic curve (AUC) analysis. The secondary outcomes were the ability of ankle systolic blood pressure (SBP) to detect hypertension (SBP > 140 mmHg) as well as bias (invasive measurement – noninvasive measurement), and agreement between the two methods using the Bland-Altman analysis.ResultsWe analyzed 415 paired readings from 30 patients. The AUC (95% confidence interval [CI]) of ankle MAP for detecting hypotension was 0.88 (0.83–0.93). An ankle MAP of ≤ 86 mmHg had negative and positive predictive values (95% CI) of 99 (97–100)% and 21 (15–29)%, respectively, for detecting hypotension. The AUC (95% CI) of ankle SBP to detect hypertension was 0.83 (0.79–0.86) with negative and positive predictive values (95% CI) of 95 (92–97)% and 36 (26–46)%, respectively, at a cutoff value of > 144 mmHg. The mean bias between the two methods was − 12 ± 17, 3 ± 12, and − 1 ± 11 mmHg for the SBP, diastolic blood pressure, and MAP, respectively.ConclusionIn patients under general anesthesia in the lateral position, ankle blood pressure measurements are not interchangeable with the corresponding invasive measurements. However, an ankle MAP > 86 mmHg can exclude hypotension with 99% accuracy, and an ankle SBP < 144 mmHg can exclude hypertension with 95% accuracy.

The Role of Serum Lactate Values as a Predictor of Morbidity in Preterm Infants

Abstract Background Early hemodynamic assessment of critically ill newborns requires mostly invasive measurements in neonatal intensive care unit. Base deficit and serum lactate concentrations may be important prognostic indicators in preterm infants. Aim and Objectives to investigate the relationship between serum lactate levels and adverse outcome in preterm infants who were admitted to NICU of Ain Shams University Hospital. Subjects and Methods This study is prospective cohort study, that included 90 preterm patients that were admitted to neonatal intensive care unit during a period of 6 months, all the neonates had the level of serum lactate been evaluated by ELISA (at 6, 12, 18 and 24 hours of birth) and correlated with the incidence of intracranial hemorrhage as diagnosed by cranial ultrasonography. Result: The initial serum lactate level was compared with the follow up readings at 12, 18 and 24 hours and showed statistically significant reduction of serum lactate in follow up recordings (p-value &amp;lt;0.05), Serum lactate was statistically significant predictors of death with increase serum lactate at 12hrs., at 18hrs. and at 24hrs, with p-value (p &amp;lt; 0.05). Serum lactate had no statistically significant association with intracranial hemorrhage as detected by transcranial ultrasonography. Conclusion Serial lactate measurements greater than 5.6 mmol/l predict adverse outcome and may aid the clinician in bedside decision making.

Evaluación invasiva de la disfunción microvascular coronaria y resultados cardiovasculares en todo el espectro de la EC: un metanálisis

Introduction and objectivesCoronary microvascular dysfunction (CMD) is highly prevalent and is recognized as an important clinical entity in patients with coronary heart disease (CHD). Nevertheless, the association of CMD with adverse cardiovascular events in the spectrum of CHD has not been systemically quantified. MethodsWe searched electronic databases for studies on patients with CHD in whom coronary microvascular function was measured invasively, and clinical events were recorded. The primary endpoint was major adverse cardiac events (MACE), and the secondary endpoint was all-cause death. Estimates of effect were calculated using a random-effects model from published risk ratios. ResultsWe included 27 studies with 11 404 patients. Patients with CMD assessed by invasive methods had a higher risk of MACE (RR, 2.18; 95%CI, 1.80-2.64; P<.01) and all-cause death (RR, 1.88; 95%CI, 1.55-2.27; P<.01) than those without CMD. There was no significant difference in the impact of CMD on MACE (interaction P value=.95) among different invasive measurement modalities. The magnitude of risk of CMD assessed by invasive measurements for MACE was greater in acute coronary syndrome patients (RR, 2.84, 95%CI, 2.26-3.57; P<.01) than in chronic coronary syndrome patients (RR, 1.77, 95%CI, 1.44-2.18; P<.01) (interaction P value<.01). ConclusionsCMD based on invasive measurements was associated with a high incidence of MACE and all-cause death in patients with CHD. The magnitude of risk for cardiovascular events in CMD as assessed by invasive measurements was similar among different methods but varied among CHD populations.

Non-invasive pulse arrival time is associated with cardiac index in pediatric heart transplant patients with normal ejection fraction

Objective. Cardiac Index (CI) is a key physiologic parameter to ensure end organ perfusion in the pediatric intensive care unit (PICU). Determination of CI requires invasive cardiac measurements and is not routinely done at the PICU bedside. To date, there is no gold standard non-invasive means to determine CI. This study aims to use a novel non-invasive methodology, based on routine continuous physiologic data, called Pulse Arrival Time (PAT) as a surrogate for CI in patients with normal Ejection Fraction (EF). Approach. Electrocardiogram (ECG) and photoplethysmogram (PPG) signals were collected from beside monitors at a sampling frequency of 250 samples per second. Continuous PAT, derived from the ECG and PPG waveforms was averaged per patient. Pearson’s correlation coefficient was calculated between PAT and CI, PAT and heart rate (HR), and PAT and EF. Main Results. Twenty patients underwent right heart cardiac catheterization. The mean age of patients was 11.7 ± 5.4 years old, ranging from 11 months old to 19 years old, the median age was 13.4 years old. HR in this cohort was 93.8 ± 17.0 beats per minute. The average EF was 54.4 ± 9.6%. The average CI was 3.51 ± 0.72 l min−1 m−2, with ranging from 2.6 to 4.77 l min−1 m−2. The average PAT was 0.31 ± 0.12 s. Pearson correlation analysis showed a positive correlation between PAT and CI (0.57, p < 0.01). Pearson correlation between HR and CI, and correlation between EF and CI was 0.22 (p = 0.35) and 0.03 (p = 0.23) respectively. The correlation between PAT, when indexed by HR (i.e. PAT × HR), and CI minimally improved to 0.58 (p < 0.01). Significance. This pilot study demonstrates that PAT may serve as a valuable surrogate marker for CI at the bedside, as a non-invasive and continuous modality in the PICU. The use of PAT in clinical practice remains to be thoroughly investigated.

Dimensions of Arachnoid Bulk Ratio: A Superior Optic Nerve Sheath Index for Intracranial Pressure.

Background Discrepancies in the literature regarding optimal optic nerve sheath diameter (ONSD) cutoffs for intracranial pressure (ICP) necessitate alternative neuroimaging parameters to improve clinical management. Purpose To evaluate the diagnostic accuracy of the dimensions of the perineural subarachnoid space to the optic nerve sheath ratio, measured using US, in predicting increased ICP. Materials and Methods In a prospective cohort study from April 2022 to December 2023, patients with suspected increased ICP underwent optic nerve US to determine the dimensions of arachnoid bulk (DAB) ratio and ONSD before invasive ICP measurement. Correlation between the parameters and ICP, as well as diagnostic accuracy, was assessed using area under the receiver operating characteristic curve (AUC) analysis. Results A total of 30 participants were included (mean age, 39 years ± 14 [SD]; 24 female). The DAB ratio and ONSD were significantly larger in participants with increased ICP (38% [0.16 of 0.42] and 14% [0.82 of 6.04 mm], respectively; P < .001). The DAB ratio showed a stronger correlation with ICP than ONSD (rs = 0.87 [P < .001] vs rs = 0.61 [P < .001]). The DAB ratio and ONSD optimal cutoffs for increased ICP were 0.5 and 6.5 mm, respectively, and the ratio had higher sensitivity (100% vs 92%) and specificity (94% vs 83%) compared with ONSD. Moreover, the DAB ratio better predicted increased ICP than ONSD, with a higher AUC (0.98 [95% CI: 0.95, 1.00] vs 0.86 [95% CI: 0.71, 0.95], P = .047). Conclusion An imaging ratio was proposed to predict ICP based on the relative anatomy of the cerebrospinal fluid space, demonstrating more accurate diagnosis of increased ICP and a strong correlation with ICP values, suggesting its potential utility as a neuroimaging marker in clinical settings. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Shepherd in this issue.