Intraoperative Beat-to-Beat Pulse Transit Time (PTT) Monitoring via Non-Invasive Piezoelectric/Piezocapacitive Peripheral Sensors Can Predict Changes in Invasively Acquired Blood Pressure in High-Risk Surgical Patients

Background: Non-invasive tracking of beat-to-beat pulse transit time (PTT) via piezoelectric/piezocapacitive sensors (PES/PCS) may expand perioperative hemodynamic monitoring. This study evaluated the ability for PTT via PES/PCS to correlate with systolic, diastolic, and mean invasive blood pressure (SBPIBP, DBPIBP, and MAPIBP, respectively) and to detect SBPIBP fluctuations. Methods: PES/PCS and IBP measurements were performed in 20 patients undergoing abdominal, urological, and cardiac surgery. A Pearson’s correlation analysis (r) between 1/PTT and IBP was performed. The predictive ability of 1/PTT with changes in SBPIBP was determined by area under the curve (reported as AUC, sensitivity, specificity). Results: Significant correlations between 1/PTT and SBPIBP were found for PES (r = 0.64) and PCS (r = 0.55) (p < 0.01), as well as MAPIBP/DBPIBP for PES (r = 0.6/0.55) and PCS (r = 0.5/0.45) (p < 0.05). A 7% decrease in 1/PTTPES predicted a 30% SBPIBP decrease (0.82, 0.76, 0.76), while a 5.6% increase predicted a 30% SBPIBP increase (0.75, 0.7, 0.68). A 6.6% decrease in 1/PTTPCS detected a 30% SBPIBP decrease (0.81, 0.72, 0.8), while a 4.8% 1/PTTPCS increase detected a 30% SBPIBP increase (0.73, 0.64, 0.68). Conclusions: Non-invasive beat-to-beat PTT via PES/PCS demonstrated significant correlations with IBP and detected significant changes in SBPIBP. Thus, PES/PCS as a novel sensor technology may augment intraoperative hemodynamic monitoring during major surgery.German Government sponsored ZIM (Zentrales Innovationsprogramm Mittelstand) programPeer Reviewe

Traveling Volunteers: A Multi‐Vendor, Multi‐Center Study on Reproducibility and Comparability of 4D Flow Derived Aortic Hemodynamics in Cardiovascular Magnetic Resonance

Background: Implementation of four-dimensional flow magnetic resonance (4D Flow MR) in clinical routine requires awareness of confounders. Purpose: To investigate inter-vendor comparability of 4D Flow MR derived aortic hemodynamic parameters, assess scan-rescan repeatability, and intra- and interobserver reproducibility. Study type: Prospective multicenter study. Population: Fifteen healthy volunteers (age 24.5 ± 5.3 years, 8 females). Field strength/sequence: 3 T, vendor-provided and clinically used 4D Flow MR sequences of each site. Assessment: Forward flow volume, peak velocity, average, and maximum wall shear stress (WSS) were assessed via nine planes (P1-P9) throughout the thoracic aorta by a single observer (AD, 2 years of experience). Inter-vendor comparability as well as scan-rescan, intra- and interobserver reproducibility were examined. Statistical tests: Equivalence was tested setting the 95% confidence interval of intraobserver and scan-rescan difference as the limit of clinical acceptable disagreement. Intraclass correlation coefficient (ICC) and Bland-Altman plots were used for scan-rescan reproducibility and intra- and interobserver agreement. A P-value 0.9: excellent, 0.75-0.9: good). Results: Ten volunteers finished the complete study successfully. 4D flow derived hemodynamic parameters between scanners of three different vendors are not equivalent exceeding the equivalence range. P3-P9 differed significantly between all three scanners for forward flow (59.1 ± 13.1 mL vs. 68.1 ± 12.0 mL vs. 55.4 ± 13.1 mL), maximum WSS (1842.0 ± 190.5 mPa vs. 1969.5 ± 398.7 mPa vs. 1500.6 ± 247.2 mPa), average WSS (1400.0 ± 149.3 mPa vs. 1322.6 ± 211.8 mPa vs. 1142.0 ± 198.5 mPa), and peak velocity between scanners I vs. III (114.7 ± 12.6 cm/s vs. 101.3 ± 15.6 cm/s). Overall, the plane location at the sinotubular junction (P1) presented most inter-vendor stability (forward: 78.5 ± 15.1 mL vs. 80.3 ± 15.4 mL vs. 79.5 ± 19.9 mL [P = 0.368]; peak: 126.4 ± 16.7 cm/s vs. 119.7 ± 13.6 cm/s vs. 111.2 ± 22.6 cm/s [P = 0.097]). Scan-rescan reproducibility and intra- and interobserver variability were good to excellent (ICC ≥ 0.8) with best agreement for forward flow (ICC ≥ 0.98). Data conclusion: The clinical protocol used at three different sites led to differences in hemodynamic parameters assessed by 4D flow. Level of evidence: 2 TECHNICAL EFFICACY STAGE: 2

Perioperative echocardiography-guided hemodynamic therapy in high-risk patients: a practical expert approach of hemodynamically focused echocardiography

The number of high-risk patients undergoing surgery is growing. To maintain adequate hemodynamic functioning as well as oxygen delivery to the vital organs (DO2) amongst this patient population, a rapid assessment of cardiac functioning is essential for the anesthesiologist. Pinpointing any underlying cardiovascular pathophysiology can be decisive to guide inter ventions in the intraoperative setting. Various techniques are available to monitor the hemodynamic status of the patient, however due to intrinsic limitations, many of these methods may not be able to directly identify the underlying cause of cardiovascular impairment. Hemodynamic focused echocardiography, as a rapid diagnostic method, ofers an excellent opportunity to examine signs of flling impairment, cardiac preload, myocardial contractility and the function of the heart valves. We thus propose a 6-step-echocardiographic approach to assess high-risk patients in order to improve and maintain perioperative DO2. The summary of all echocardiographic based fndings allows a diferentiated assessment of the patient’s cardiovascular function and can thus help guide a (patho)physiological-orientated and individualized hemodynamic therapy

Current Anesthetic Care of Patients Undergoing Transcatheter Aortic Valve Replacement in Europe:Results of an Online Survey

Objectives: Transcatheter aortic valve replacement (TAVR) has become an alternative treatment for patients with symptomatic aortic stenosis not eligible for surgical valve replacement due to a high periprocedural risk or comorbidities. However, there are several areas of debate concerning the pre-, intra- and post-procedural management. The standards and management for these topics may vary widely among different institutions and countries in Europe. Design: Structured web-based, anonymized, voluntary survey. Setting: Distribution of the survey via email among members of the European Association of Cardiothoracic Anaesthesiology working in European centers performing TAVR between September and December 2018. Participants: Physicians. Measurements and main results: The survey consisted of 25 questions, including inquiries regarding number of TAVR procedures, technical aspects of TAVR, medical specialities present, preoperative evaluation of TAVR candidates, anesthesia regimen, as well as postoperative management. Seventy members participated in the survey. Reporting members mostly performed 151-to-300 TAVR procedures per year. In 90% of the responses, a cardiologist, cardiac surgeon, cardiothoracic anesthesiologist, and perfusionist always were available. Sixty-six percent of the members had a national curriculum for cardiothoracic anesthesia. Among 60% of responders, the decision for TAVR was made preoperatively by an interdisciplinary heart team with a cardiothoracic anesthesiologist, yet in 5 countries an anesthesiologist was not part of the decision-making. General anesthesia was employed in 40% of the responses, monitored anesthesia care in 44%, local anesthesia in 23%, and in 49% all techniques were offered to the patients. In cases of general anesthesia, endotracheal intubation almost always was performed (91%). It was stated that norepinephrine was the vasopressor of choice (63% of centers). Transesophageal echocardiography guiding, whether performed by an anesthesiologist or cardiologist, was used only Conclusion: The results indicated that requirements and quality indicators (eg, periprocedural anesthetic management, involvement of the anesthesiologist in the heart team, etc) for TAVR procedures as published within the European guideline are largely, yet still not fully implemented in daily routine. In addition, anesthetic TAVR management also is performed heterogeneously throughout Europe. (C) 2020 Elsevier Inc. All rights reserved

Analysis of blood flow patterns in the ascending aorta after different types of surgical aortic valve replacement with cardiovascular magnetic resonance imaging

Einleitung Es bestehen Hinweise darauf, dass der Aortenklappenersatz zu einer veränderten Hämodynamik führt und es in Folge dessen zu Umbauerscheinungen der Aorta ascendens kommt. Die in der Routine verwendete Echokardiographie weist den Nachteil auf, dass eine eingeschränkte Darstellung der Aorta ascendens mit resultierender Tendenz zur Unterschätzung der Prävalenz von Aortendilatationen möglich ist und das Flussverhalten nur durch die maximalen und mittleren Druckgradienten sowie die Geschwindigkeit charakterisiert wird. Die geschwindigkeitskodierte dreidimensionale und zeitlich aufgelöste Phasenkontrastmessung (4D-Fluss MRT) stellt eine relativ neue Möglichkeit dar, Flussmuster sowie Flussparameter wie Wandscherkräfte und Geschwindigkeiten zu bestimmen. Fragestellung Ziel dieser Arbeit ist es, die Machbarkeit der 4D- Fluss MRT für die verschiedenen Formen des Aortenklappenersatzes zu zeigen und eine erste hämodynamische Charakterisierung der unterschiedlichen Formen des Aortenklappenersatzes vorzunehmen. Methoden 38 Patienten mit einem Aortenklappenersatz (14 gerüsthaltige, 8 gerüstlose, 9 mechanische und 7 Autografts) sowie 9 Kontrollprobanden wurden mittels 4D-Fluss-MRT in einem 1,5 Tesla-MRT ohne Kontrastmittelapplikation untersucht. Zur Bestimmung der Klappenöffnungsfläche sowie linksventrikulären Funktion und Weite der Aorta ascendens wurden SSFP-Sequenzen verwendet. Drei Analyseschichten auf Höhe des sinotubulären Übergangs, der Mitte der Aorta ascendens sowie vor Abgang des Truncus brachiocephalicus wurden platziert. Die Blutflussmusterdarstellung erfolgte durch Stream- und Pathlines und wurde in Helices und Vortices anhand einer in der Literatur beschriebenen semiquantitativen Klassifikation eingeteilt. Die Blutflussparameteranalyse erfolgte schichtweise und segmentweise für 12 Segmente entlang der Zirkumferenz der Analyseschicht. Maximale und mittlere Geschwindigkeiten, Gesamtwandscherkräfte sowie axiale, inplane und zirkumferentielle Wandscherkräfte, oszillierende Wandscherindices und Blutflussexzentrizitäten wurden bestimmt. Ergebnisse Gerüsthaltige Bioprothesen zeigten vermehrt Vortices und Helices als die Kontrollen, Autografts und gerüstlosen Prothesen. Bei gerüsthaltigen Prothesen wurde eine höhere maximale Flussgeschwindigkeiten als bei mechanischen Prothesen, Autografts und Kontrollen vorgefunden. Nur eine segmentweise Analyse der Wandscherkräfte ergab signifikante Unterschiede. Axiale und Gesamtwandscherkräfte wiesen höhere Werte an der rechts-äußeren Kurvatur bei gerüsthaltigen und gerüstlosen biologischen Prothesen in Schicht zwei auf. Kontrollen und Autografts zeigten eine gleichmäßige Verteilung der Wandscherkräfte. Bei Analyse der Differenzen der Wandscherkräfte und der visuellen Beurteilung zeigte sich, dass alle mechanischen, gerüstlosen und gerüsthaltigen Prothesen einen exzentrischen Fluss aufwiesen. Der exzentrische Fluss war bis auf drei mechanische Prothesen auf die rechts-äußere Kurvatur gerichtet. Autografts waren die einzige Form, bei der auch ein zentraler Fluss beobachtet werden konnte. Diskussion Alle Formen des Aortenklappenersatzes unterschieden sich sowohl untereinander als auch von den Kontrollen in Bezug auf Flussmuster und –parameter. Die 4D-Fluss-MRT ist bei verschiedenen Formen des Aortenklappenersatzes anwendbar und gewährt neue Erkenntnisse hinsichtlich hämodynamischer Veränderungen nach einer Aortenklappenintervention.Background Aortic valve replacement is a standard procedure in heart surgery. There is evidence that the intervention alters the hemodynamics which ultimately leads to a remodeling of the ascending aorta. Echocardiography used in routine has the disadvantage to only display certain parts of the ascending aorta. As a consequence, the prevalence of dilatations is underestimated. Moreover, the hemodynamics are only characterized by the maximum and average pressure gradient and the velocity. 3D cine phase contrast cardiovascular magnetic resonance (4D Flow) is a new technique to investigate flow patterns and parameters. It was the object to demonstrate the feasibility of the 4D Flow technique in the context of different types of aortic valve prosthesis and to conduct a first hemodynamic characterization of the aortic valve replacement. Methods 38 patients with various forms of aortic valve replacement (14 stented, eight stentless, nine mechanical, seven autografts) and nine healthy controls underwent an MRI examination without the use of contrast media. SSFP-sequences were used to determine the valve orifice area, left ventricular function as well as the diameter of the ascending aorta. Three analysis planes were positioned at the level of the sinotubular junction, the midway of the ascending aorta and proximal to the brachiocephalic trunk. The analysis of the different blood flow patterns was done by using streamlines and pathlines. They were graduated into helices and vortices using a semiquantitative approach published in the literature. Blood flow patterns were analysed slicewise and segmentwise for twelve segments along the circumference. The maximum and average velocities, total, axial, inplane, circumferential and oscillatoric wall shear stresses as well as blood flow excenticities were determined. Results Patients with a stented bioprosthesis had an increased incidence of vortices and helices as compared to patients with autografts, stentless prostheses and control subjects. There was also a higher maximum velocity in contrast to patients with mechanical prostheses, autografts and control subjects. Only a segmentwise analysis of the wall shear stresses was able to show a significant difference in stented and stentless prostheses. Axial and total wall shear stresses had increased magnitudes at the right outer curvature in slice two. Controls and autografts had an equal distribution of wall shear stresses. When analyzing the differences of the wall shear stresses and visualizing the distribution it turned out that all patients with mechanical, stentless and stented prostheses had an eccentric flow. It was directed to the right outer curvature except for three mechanical prostheses. Autografts were the only form of aortic valve replacement that yielded a central flow. Conclusions All forms of aortic valve replacement differed among each other as well as in comparison to native aortic valves concerning the blood flow patterns and flow parameters. 4D Flow is a feasible technique to examine different types of aortic valve replacement and promises to allow gaining new insights into the remodeling process of the great vessels after an aortic valve intervention

High Central Venous Pressure after Cardiac Surgery Might Depict Hemodynamic Deterioration Associated with Increased Morbidity and Mortality

Background: Cardiac surgery patients represent a high-risk cohort in intensive care units (ICUs). Central venous pressure (CVP) measurement seems to remain an integral part in hemodynamic monitoring, especially in cardio-surgical ICUs. However, its value as a prognostic marker for organ failure is still unclear. Therefore, we analyzed postoperative CVP values after adult cardiac surgery in a large cohort with regard to its prognostic value for morbidity and mortality. Methods: All adult patients admitted to our ICUs between 2006 and 2019 after cardiac surgery were eligible for inclusion in the study (n = 11,198). We calculated the median initial CVP (miCVP) after admission to the ICU, which returned valid values for 9802 patients. An ROC curve analysis for optimal cut-off miCVP to predict ICU mortality was conducted with consecutive patient allocation into a (a) low miCVP (LCVP) group (≤11 mmHg) and (b) high miCVP (HCVP) group (&gt;11 mmHg). We analyzed the impact of high miCVP on morbidity and mortality by propensity score matching (PSM) and logistic regression. Results: ICU mortality was increased in HCVP patients. In addition, patients in the HCVP group required longer mechanical ventilation, had a higher incidence of acute kidney injury, were more frequently treated with renal replacement therapy, and showed a higher risk for postoperative liver dysfunction, parametrized by a postoperative rise of ≥ 10 in MELD Score. Multiple regression analysis confirmed HCVP has an effect on postoperative ICU-mortality and intrahospital mortality, which seems to be independent. Conclusions: A high initial CVP in the early postoperative ICU course after cardiac surgery is associated with worse patient outcome. Whether or not CVP, as a readily and constantly available hemodynamic parameter, should promote clinical efforts regarding diagnostics and/or treatment, warrants further investigations

Multi-site comparison of parametric T1 and T2 mapping: healthy travelling volunteers in the Berlin research network for cardiovascular magnetic resonance (BER-CMR)

Abstract Background Parametric mapping sequences in cardiovascular magnetic resonance (CMR) allow for non-invasive myocardial tissue characterization. However quantitative myocardial mapping is still limited by the need for local reference values. Confounders, such as field strength, vendors and sequences, make intersite comparisons challenging. This exploratory study aims to assess whether multi-site studies that control confounding factors provide first insights whether parametric mapping values are within pre-defined tolerance ranges across scanners and sites. Methods A cohort of 20 healthy travelling volunteers was prospectively scanned at three sites with a 3 T scanner from the same vendor using the same scanning protocol and acquisition scheme. A Modified Look-Locker inversion recovery sequence (MOLLI) for T1 and a fast low-angle shot sequence (FLASH) for T2 were used. At one site a scan-rescan was performed to assess the intra-scanner reproducibility. All acquired T1- and T2-mappings were analyzed in a core laboratory using the same post-processing approach and software. Results After exclusion of one volunteer due to an accidentally diagnosed cardiac disease, T1- and T2-maps of 19 volunteers showed no significant differences between the 3 T sites (mean ± SD [95% confidence interval] for global T1 in ms: site I: 1207 ± 32 [1192–1222]; site II: 1207 ± 40 [1184–1225]; site III: 1219 ± 26 [1207–1232]; p = 0.067; for global T2 in ms: site I: 40 ± 2 [39–41]; site II: 40 ± 1 [39–41]; site III 39 ± 2 [39–41]; p = 0.543). Conclusion Parametric mapping results displayed initial hints at a sufficient similarity between sites when confounders, such as field strength, vendor diversity, acquisition schemes and post-processing analysis are harmonized. This finding needs to be confirmed in a powered clinical trial. Trial registration ISRCTN14627679 (retrospectively registered

Echocardiographic Evaluation of Right Ventricular (RV) Performance over Time in COVID-19-Associated ARDS—A Prospective Observational Study

(1) Background: To evaluate time-dependent right ventricular (RV) performance in patients with COVID-19-associated acute respiratory distress syndrome (ARDS) undergoing intensive care (ICU) treatment. (2) Methods: This prospective observational study included 21 ICU patients with COVID-19-associated ARDS in a university hospital in 2020 (first wave). Patients were evaluated by transthoracic echocardiography at an early (EE) and late (LE) stage of disease. Echocardiographic parameters describing RV size and function as well as RV size in correlation to PaO2/FiO2 ratio were assessed in survivors and nonsurvivors. (3) Results: Echocardiographic RV parameters were within normal range and not significantly different between EE and LE. Comparing survivors and nonsurvivors revealed no differences in RV performance at EE. Linear regression analysis did not show a correlation between RV size and PaO2/FiO2 ratio over all measurements. Analysing EE and LE separately showed a significant increase in RV size correlated to a lower PaO2/FiO2 ratio at a later stage of COVID-19 ARDS. (4) Conclusion: The present study reveals neither a severe RV dilatation nor an impairment of systolic RV function during the initial course of COVID-19-associated ARDS. A trend towards an increase in RV size in correlation with ARDS severity in the second week after ICU admission was observed