Comparison of coagulation monitoring using ROTEM and Sonoclot devices in cardiac surgery: a single-center prospective observational study.

BACKGROUND: Viscoelastic tests (VETs) are recommended during cardiac surgery to monitor coagulation status and guide transfusion. We compared the results of two VETs, the Sonoclot Analyzer and the ROTEM Sigma. Agreement between viscoelastic tests' subdiagnoses and overall diagnosis severity was assessed. Correlations with conventional coagulation tests (CCT) and the discriminatory potential of numerical VET outputs for transfusion thresholds was determined. METHODS: Single-center, prospective observational study in a tertiary academic center. In fifty adult patients undergoing elective cardiac surgery, parallel Sonoclot, ROTEM and CCT analysis was performed before heparin, or after protamine or coagulation product administration. All patients completed the study, resulting in 139 data points. RESULTS: Agreement on the severity of coagulation disorders was acceptable (83%), but poor (27%) on the differentiation of the underlying causes. Correlations between ROTEM parameters and CCT were good (postprotamine: FIBTEM A5 (r2=0.90 vs. fibrinogen) and EXTEM-FIBTEM A5 difference (r2=0.81 vs. platelet count). Sonoclot correlated less (Clot Rate (r2=0.25 vs. fibrinogen) and Platelet Function (r2=0.43 vs. platelet count). This was reflected in the discriminatory potential of these parameters as found by linear mixed modelling. We suggest clinically useful grey zones for VET cutoff interpretation. CONCLUSIONS: ROTEM and Sonoclot accord well on the detection of severity of coagulation dysfunction, but not on the diagnosis of the underlying cause. ROTEM correlated more closely with CCT then Sonoclot. We propose a testing strategy that could lead to a cost-effective approach to the bleeding cardiac surgery patient.

Incongruous effect of phenylephrine on changes in cerebral blood volume measured by near-infrared spectroscopy (NIRS) indicating extracranial contamination.

We assessed extracranial contamination of the near-infrared spectroscopy (NIRS) signal during administration of phenylephrine. The study was performed with NIRO 200NX which employs both the Modified Beer-Lambert (MBL) method to measure total hemoglobin (tHb, expressed in µM), and Spatially Resolved Spectroscopy (SRS) to measure total hemoglobin content (nTHI, expressed in arbitrary units (a.u.)). SRS tends to not be affected by extracranial blood flow. As vasoconstriction with phenylephrine mainly occurs in the extracranial area, we hypothesized that if NIRS measurements are indeed prone to extracranial contamination, tHb will be more affected by the administration of phenylephrine than nTHI. After ethical committee approval, 20 consenting cardiac surgery patients were included. Phenylephrine was administered whenever clinically indicated and its effect on nTHI and tHb was evaluated. To adjust for the difference in raw scale units, Z-scores were calculated. Data were analyzed with Wilcoxon Signed Ranks Test and the Hodges-Lehmann method. A total of 191 data sets were obtained in 20 patients (10 male, 65 ± 15 years, 77 ± 16 kg, 166 ± 11 cm). The median difference before and after administration of phenylephrine was - 0.006 a.u. [95%CI - 0.010 to - 0.002] (p < 0.001) and - 0.415 µM [95%CI - 0.665 to - 0.205] (p < 0.001) for nTHI and tHb, respectively. The median difference between the Z-scores of nTHI and tHb was - 0.02 [95%CI - 0.04 to - 0.003] (p = 0.03), with a higher variability in the Z-scores of tHb. Phenylephrine induced significant larger changes in MBL values compared to SRS values, indicating that the MBL method might be more prone to extracranial contamination. Trial and clinical registry: Trial registration number: B670201939459, ethical committee number: 2019/0265, date of approval: March 19, 2019.

Assessing Left Ventricular Early Diastolic Velocities With Tissue Doppler and Speckle Tracking by Transesophageal and Transthoracic Echocardiography.

BACKGROUND: Assessing diastolic dysfunction is essential and should be part of every routine echocardiography examination. However, clinicians routinely observe lower mitral annular velocities by transesophageal echocardiography (TEE) under anesthesia than described by awake transthoracic echocardiography (TTE). It would be important to know whether this difference persists under constant loading conditions. We hypothesized that mean early diastolic mitral annular velocity, measured by tissue Doppler imaging (TDI, JOURNAL/asag/04.03/00000539-202105000-00029/inline-graphic1/v/2021-04-15T211206Z/r/image-tiff) would be different in the midesophageal 4-chamber (ME 4Ch) than in the apical 4-chamber (AP 4Ch) view under unchanged or constant loading conditions. Secondarily we examined (1) JOURNAL/asag/04.03/00000539-202105000-00029/inline-graphic2/v/2021-04-15T211206Z/r/image-tiff in an alternative transesophageal view with presumed superior Doppler beam alignment, the deep transgastric view (DTG), compared to those in the AP 4Ch, and (2) early diastolic speckle tracking-based strain rate (JOURNAL/asag/04.03/00000539-202105000-00029/inline-graphic3/v/2021-04-15T211206Z/r/image-tiff), in the ME 4Ch and in the AP 4Ch. METHODS: Twenty-five consecutive adult patients undergoing on-pump cardiac surgery from February 2017 to July 2017 were included. Both TTE and TEE measurements were obtained under anesthesia in a randomized order in the AP 4Ch, ME 4Ch, and DTG views. Within-patient average values were compared by paired t tests with a Bonferroni adjustment. Box plots, correlation, and agreement by Bland-Altman were examined for all 3 comparisons. A second echocardiographer independently acquired and analyzed images; images were reanalyzed after 4 weeks. Image quality and reproducibility were also reported. RESULTS: Averaged JOURNAL/asag/04.03/00000539-202105000-00029/inline-graphic4/v/2021-04-15T211206Z/r/image-tiff measurements were lower in the ME 4Ch than in the AP 4Ch (6.6 ± 1.7 cm/s vs 7.0 ± 1.5 cm, P = .028; within-patient difference mean ± standard deviation: 0.6 ± 1.2 cm/s). An alternative TEE view for JOURNAL/asag/04.03/00000539-202105000-00029/inline-graphic5/v/2021-04-15T211206Z/r/image-tiff, the DTG, also exhibited lower mean values (6.0 ± 1.6 cm/s, P = .006; within-patient difference mean ± standard deviation: 1.1 ± 1.8 cm/s). JOURNAL/asag/04.03/00000539-202105000-00029/inline-graphic6/v/2021-04-15T211206Z/r/image-tiff strain rate showed a low degree of bias, but greater variability (ME 4Ch: 0.87 ± 0.32%/s vs AP 4Ch: 0.73 ± 0.18%/s, P = .078; within-patient difference mean ± standard deviation: -0.1 ± 0.2%/s). CONCLUSIONS: This study confirms that TEE modestly underestimates JOURNAL/asag/04.03/00000539-202105000-00029/inline-graphic7/v/2021-04-15T211206Z/r/image-tiff but not to a clinically relevant extent. While JOURNAL/asag/04.03/00000539-202105000-00029/inline-graphic8/v/2021-04-15T211206Z/r/image-tiff in the DTG is not a promising alternative, the future role for speckle tracking-based early diastolic strain rate is unknown.

Rapid, Single-View Speckle-Tracking-Based Method for Examining Left Ventricular Systolic and Diastolic Function in Point of Care Ultrasound.

OBJECTIVES: A rapid, reliable quantitative assessment of left ventricular systolic and diastolic function is important for patient treatment in urgent and dynamic settings. Quantification of annular velocities based on a single 2-dimensional image loop, rather than on Doppler velocities, could be useful in point-of-care or focused cardiac ultrasound. We hypothesized that novel speckle-tracking-based mitral annular velocities would correlate with reference standard tissue Doppler imaging (TDI) velocities in a focused cardiac ultrasound-esque setting. METHODS: Two echocardiographers each performed transthoracic echocardiographic measurements before and after induction of anesthesia in supine patients undergoing cardiac surgery. Speckle-tracking echocardiography (STE)-based systolic (S'STE ) and diastolic (E'STE and A'STE ) velocities were compared to TDI and global longitudinal strain/strain rate. We also compared mitral annular displacement by speckle tracking with M-mode imaging. RESULTS: Twenty-five patients were included and examined in both preinduction and postinduction states. Speckle-tracking-based velocities correlated with TDI measurements in both states (S', r = 0.73 and 0.76; E', r = 0.87 and 0.65; and A', r = 0.65 and 0.73), showing a mean bias of 25% to 30% of the reference standard measurement. The correlation of S'STE with strain and the strain rate (S-wave) and E'STE with the strain rate (E-wave) was good in awake, spontaneously breathing patients but was less strong in the ventilated state. Similarly, displacement by speckle tracking correlated with M-mode measurements in both states (r = 0.91 and 0.84). Measurements required medians of 31 and 34 seconds; reproducibility was acceptable for S'STE and E'STE . CONCLUSIONS: Speckle-tracking-based mitral annular velocities and displacement correlate well with conventional measures as well as with deformation imaging. They may be clinically useful in rapidly assessing both systolic and diastolic function from a single 2-dimensional image loop.

Right Ventricular Systolic Assessment by Transesophageal Versus Transthoracic Echocardiography: Displacement, Velocity, and Myocardial Deformation.

OBJECTIVE: First, to compare tricuspid annular displacement and velocity in transthoracic and transesophageal echocardiography (TTE, TEE) using conventional angle-dependent technologies. Second, to evaluate both alternative TEE views as well as an alternative technology (speckle tracking) for overcoming proposed differences in TTE and TEE. DESIGN: Prospective, comparative, cross-over study with a randomized order of image acquisition. SETTING: University hospital. PARTICIPANTS: Adults undergoing cardiac surgery. INTERVENTIONS: Postinduction standardized image acquisition and analysis in TTE and TEE by 2 echocardiographers. MEASUREMENTS AND MAIN RESULTS: The authors measured tricuspid annular plane systolic excursion (TAPSE) by M-mode and velocity by tissue Doppler (S') in the apical 4-chamber TTE view and midesophageal 4-chamber TEE view (AP4C, ME4C). They then examined (1) the same measurements in alternative TEE views with proposed better ultrasound angulation; and (2) speckle tracking-based endpoints (TAPSE by speckle tracking, strain, and strain rate). Data were available in 24 of 25 patients. Conventional TAPSE by M-mode and velocity by tissue Doppler (TDI) were underestimated in the ME4C compared with the AP4C reference (mean ± standard deviation: TAPSE: 13.1 ± 3.8 mm v 17.3 ± 4.0 mm; S': 6.7 ± 2.1 cm/s v 9.1 ± 2.2 cm/s; both p < 0.001). Neither a modified deep transgastric view (TAPSE 14.5 ± 4.7 mm, p = 0.017; S' 6.8 ± 1.8 cm/s, p < 0.001) nor a transgastric right ventricular inflow view (TAPSE 12.3 ± 4.0 mm, p = 0.001; S' 6.0 ± 1.3 cm/s, p < 0.001) was similar to the AP4C. Speckle tracking TAPSE was unbiased but with high variability (mean bias = -0.3 mm, 95% limits of agreement = -9.1 to 8.4); strain and strain rate were higher in TEE than for TTE (-17.7 ± 3.6 v -12.6 ± 2.1, p < 0.001; -1.0 ± 0.2/s v -0.7 ± 0.1/s, p < 0.001). CONCLUSIONS: Right ventricular displacement, velocity, and myocardial deformation measured by TEE versus TTE are different. Neither alternative transesophageal echocardiography views nor speckle tracking-based deformation is promising; TAPSE by speckle tracking is unbiased but imprecise.

The impact of cardiopulmonary bypass management on outcome: a propensity matched comparison between minimally invasive and conventional valve surgery.

OBJECTIVES: Research concerning cardiopulmonary bypass (CPB) management during minimally invasive cardiac surgery (MICS) is scarce. We investigated the effect of CPB parameters such as pump flow, haemoglobin concentration and oxygen delivery on clinical outcome and renal function in a propensity matched comparison between MICS and median sternotomy (MS) for atrioventricular valve surgery. METHODS: A total of 356 patients undergoing MICS or MS for atrioventricular valve surgery between 2006 and 2017 were analysed retrospectively. Propensity score analysis matched 90 patients in the MS group with 143 in the MICS group. Logistic regression analysis was performed to investigate independent predictors of cardiac surgery-associated acute kidney injury in patients having MICS. RESULTS: In MICS, CPB (142.9 ± 39.4 vs 101.0 ± 38.3 min; P < 0.001) and aortic cross-clamp duration (89.9 ± 30.6 vs 63.5 ± 23.0 min; P < 0.001) were significantly prolonged although no differences in clinical outcomes were detected. The pump flow index was lower [2.2 ± 0.2 vs 2.4 ± 0.1 l⋅(min⋅m2)-1; P < 0.001] whereas intraoperative haemoglobin levels were higher (9.25 ± 1.1 vs 8.8 ± 1.2; P = 0.004) and the nadir oxygen delivery was lower [260.8 ± 43.5 vs 273.7 ± 43.7 ml⋅(min⋅m2)-1; P = 0.029] during MICS. Regression analysis revealed that the nadir haemoglobin concentration during CPB was the sole independent predictor of cardiac surgery-associated acute kidney injury (odds ratio 0.67, 95% confidence interval 0.46-0.96; P = 0.029) in MICS but not in MS. CONCLUSIONS: Specific cannulation-related issues lead to CPB management during MICS being confronted with flow restrictions because an average pump flow index ≤2.2 l/min/m2 is achieved in 40% of patients who have MICS compared to those who have a conventional MS. This study showed that increasing the haemoglobin level might be helpful to reduce the incidence of cardiac surgery-associated acute kidney injury after minimally invasive mitral valve surgery.

Assessing Right Ventricular Function in the Perioperative Setting, Part I: Echo-Based Measurements.

This article reviews transesophageal echocardiography-based assessment of perioperative right ventricular function and failure, including catheter-based methods, three-dimensional echocardiography, and their combination to make pressure-volume loops. It outlines right ventricular pathophysiology, multiple assessment methods, and their relationship to analogous transthoracic echocardiogram measurements. technologies used and developed for transthoracic or left ventricular assessment show significant limitations when applied to transesophageal assessment of the right ventricle. The article provides an overview of right ventricular assessment modalities that can be used in transesophageal echocardiography. Ultimately, clinicians must know limitations of measurements, synthesize information, and assess it in the clinical context.

Assessing Right Ventricular Function in the Perioperative Setting, Part II: What About Catheters?

An-depth assessment of right ventricular function is important in a many perioperative settings. After exploring 2-dimensional echo-based evaluation, other proposed monitoring modalities are discussed. Pressure-based methods of right ventricular appraisal is discussed. Flow-based assessment is reviewed. An overview of the state of current right ventricular 3-dimensional echocardiography and its potential to construct clinical pressure-volume loops in conjunction with pressure measurements is provided. An overview of right ventricular assessment modalities that do not rely on 2-dimensional echocardiography is discussed. Tailored selection of monitoring modalities can be of great benefit for the perioperative physician. Integrating modalities offers optimal estimations of right ventricular function.

A Novel Speckle-Tracking Based Method for Quantifying Tricuspid Annular Velocities in TEE.

OBJECTIVES: A novel speckle-tracking-based option for measuring tricuspid annular velocities in the midesophageal 4-chamber view (ME4C) was compared with velocities measured by tissue Doppler in the apical-4 chamber view (AP4C). Because this method was based on a modified speckle-tracking-based measurement of tricuspid annular plane systolic excursion (TAPSE), the authors also compared TAPSE by speckle tracking in the ME4C with TAPSE by M-mode in the AP4C. The authors hypothesized that velocities measured by speckle tracking in transesophageal echocardiography (TEE) would be similar, correlate, and agree with those measured by tissue Doppler in transthoracic echocardiography (TTE). DESIGN: Prospective diagnostic study with randomization of the order of post-induction echocardiography views by TTE (AP4C) and TEE (ME4C). Images were both acquired and analyzed by 2 echocardiographers independently. The primary outcome was S'; secondary outcomes were E', A', and TAPSE. SETTING: Single university hospital. PARTICIPANTS: Consecutive adult patients undergoing cardiac surgery (mainly coronary artery bypass grafting). INTERVENTIONS: None. MAIN RESULTS: Complete data was available in 24 of 25 patients. For the primary outcome, S' measured by speckle tracking in the ME4C correlated and agreed with S' measured by tissue Doppler in the AP4C (S'STE = 0.87STDI + 0.60, p < 0.001, r = 0.78; mean bias -0.6 cm/s, 95% limits of agreement (LoA) -3.5 to 2.4 cm/s). Similarly results were found for E', but not A' (E'STE = 0.69E'TDI + 2.37, p < 0.001, r = 0.71; mean bias 0.1 cm/s, 95%LoA -2.5 to 2.8cm/s; A'STE = 0.15A'TDI + 11.17, p = 0.629). TAPSE measurements by the authors' modified speckle-tracking-based technique were similar to TAPSE by M-mode (18.2 ± 5.5 mm and 17.1 ± 3.9 mm, respectively). CONCLUSIONS: Tricuspid annular velocities (S'STE, E'STE) determined by speckle tracking in TEE seem to be promising surrogates for velocities measured in TTE. This may be important for perioperative assessment of the right ventricle.

Elastic image registration to quantify 3-D regional myocardial deformation from volumetric ultrasound: experimental validation in an animal model.

Although real-time 3-D echocardiography has the potential to allow more accurate assessment of global and regional ventricular dynamics compared with more traditional 2-D ultrasound examinations, it still requires rigorous testing and validation should it break through as a standard examination in routine clinical practice. However, only a limited number of studies have validated 3-D strain algorithms in an in vivo experimental setting. The aim of the present study, therefore, was to validate a registration-based strain estimation methodology in an animal model. Volumetric images were acquired in 14 open-chest sheep instrumented with ultrasonic microcrystals. Radial strain (ɛRR), longitudinal strain (ɛLL) and circumferential strain (ɛCC) were estimated during different stages: at rest, during reduced and increased cardiac inotropy induced by esmolol and dobutamine infusion, respectively, and during acute ischemia. Agreement between image-based and microcrystal-based strain estimates was evaluated by their linear correlation, indicating that all strain components could be estimated with acceptable accuracy (r = 0.69 for ɛRR, r = 0.64 for ɛLL and r = 0.62 for ɛCC). These findings are comparable to the performance of the current state-of-the-art commercial 3-D speckle tracking methods. Furthermore, shape of the strain curves, timing of peak values and location of dysfunctional regions were identified well. Whether 3-D elastic registration performs better than 3-D block matching-based methodologies still remains to be proven.

A pathophysiological approach towards right ventricular function and failure.

The scope of this review is to provide a pathophysiological summary of perioperative right ventricular function and failure. In recent decades, the importance of right ventricular function in the perioperative period has been established. However, much of our current knowledge on the management of this clinical entity is based on extrapolation of results from left ventricular research, although biventricular physiology is known to be markedly different in many aspects. Here, on the basis of a thorough literature search, we review theoretical as well as practical aspects of perioperative right ventricular failure. After underlining the importance of this topic, we review basic right ventricular anatomy and physiology, with an emphasis on the role of ventricular interaction. Next, potential causes of perioperative right ventricular failure are discussed. The emphasis of this review is on the perioperative anaesthetic considerations, ranging from preoperative assessment through intraoperative monitoring to specific contemporary therapeutic options of perioperative right ventricular failure.