Relation of pulmonary vein to mitral flow velocities by transesophageal Doppler echocardiography. Effect of different loading conditions

MRI-based modelling of left atrial flow and coagulation to predict risk of thrombogenesis in atrial fibrillation

Atrial fibrillation (AF), impacting nearly 50 million individuals globally, is a major contributor to ischaemic strokes, predominantly originating from the left atrial appendage (LAA). Current clinical scores like CHA₂DS₂-VASc, while useful, provide limited insight into the pro-thrombotic mechanisms of Virchow's triad-blood stasis, endothelial damage, and hypercoagulability. This study leverages biophysical computational modelling to deepen our understanding of thrombogenesis in AF patients. Utilising high temporal resolution Cine magnetic resonance imaging (MRI), a 3D patient-specific modelling pipeline for simulating patient-specific flow in the left atrium was developed. This computational fluid dynamics (CFD) approach was coupled with reaction-diffusion-convection equations for key clotting proteins, leading to an innovative risk stratification score that combines clinical and modelling data. This approach categorises thrombogenic risk into low (A), moderate (B), and high (C) levels. Applied to a cohort of nine patients, pre- and post-catheter ablation therapy, this approach generates novel risk scores of thrombus formation, which are based of mechanistic characterisation of all aspects of the Virchow's triad. Currently, thrombogenesis mechanisms are not factored in widespread clinical risks scores based on demographic characteristics and co-morbidities. Notably, some patients with a CHA₂DS₂-VASc score of 0 (lowest clinical risk) exhibited much higher risks once the individual pathophysiology was accounted for. This discrepancy highlights the limitations of the CHA₂DS₂-VASc score in providing detailed mechanistic insights into patient-specific thrombogenic risk. This work introduces a comprehensive method for assessing thrombus formation risks in AF patients, emphasising the value of integrating biophysical modelling with clinical scores to enhance personalised stroke prevention strategies.

The prognostic value of changes in pulmonary vein flow patterns after surgical repair for primary mitral regurgitation

BACKGROUND

The pulmonary vein (PV) flow pattern is influenced by the presence of mitral regurgitation (MR). After a successful reduction in MR severity, the pattern is expected to be changed. We aimed to evaluate the prognostic value of a change in the PV flow pattern in patients with primary MR undergoing mitral valve repair (MVR).

METHODS

The PV flow pattern was assessed with transthoracic echocardiography in 216 patients (age 65 [IQR 56-72] years, 70% male) with primary MR before and after surgical MVR. The population was divided according to a change in the PV flow pattern following MVR into 'improvers' and 'non-improvers'.

RESULTS

Non-improvers (15%) had a higher prevalence of paroxysmal AF at baseline (46% vs. 22%, p = 0.004), left ventricular dysfunction (LVEF ≤60%) (39% vs. 21%, p = 0.020), and had lower systolic pulmonary artery pressure (28[IQR 25-38] vs. 35[IQR 26-48] mmHg, p = 0.018) compared to improvers (85%). After a median follow-up of 83[IQR 43-140] months, 26(12%) patients died. Non-improvers had higher mortality rates than improvers (p = 0.009). On multivariable Cox regression analysis, a lack of improvement in the PV flow pattern remained independently associated with all-cause mortality (HR 2.322, 95% CI 1.140 to 4.729, P = 0.020).

CONCLUSION

A lack of improvement in the PV flow pattern is independently associated with worse long-term survival in patients with primary MR undergoing MVR.

Impact of left atrial appendage occlusion device position on potential determinants of device-related thrombus: a patient-specific in silico study

BACKGROUND

Device-related thrombus (DRT) after left atrial appendage occlusion (LAAO) is potentially linked to adverse events. Although clinical reports suggest an effect of the device type and position on the DRT risk, in-depth studies of its mechanistic basis are needed. This in silico study aimed to assess the impact of the position of non-pacifier (Watchman) and pacifier (Amulet) LAAO devices on surrogate markers of DRT risk.

METHODS

The LAAO devices were modeled with precise geometry and virtually implanted in different positions into a patient-specific left atrium. Using computational fluid dynamics, the following values were quantified: residual blood, wall shear stress (WSS) and endothelial cell activation potential (ECAP).

RESULTS

In comparison to an ostium-fitted device position, deep implantation led to more residual blood, lower average WSS and higher ECAP surrounding the device, especially on the device's atrial surface and the surrounding tissue, suggesting increased risk for potential thrombus. For the non-pacifier device, an off-axis device orientation resulted in even more residual blood, higher ECAP and similar average WSS as compared to an ostium-fitted device position. Overall, the pacifier device showed less residual blood, higher average WSS and lower ECAP, compared to the non-pacifier device.

CONCLUSIONS

In this in silico study, both LAAO device type and implant position showed an impact on potential markers of DRT in terms of blood stasis, platelet adhesion and endothelial dysfunction. Our results present a mechanistic basis for clinically observed risk factors of DRT and the proposed in silico model may aid in the optimization of device development and procedural aspects.

Impact of left atrial wall motion assumptions in fluid simulations on proposed predictors of thrombus formation

Atrial fibrillation (AF) poses a significant risk of stroke due to thrombus formation, which primarily occurs in the left atrial appendage (LAA). Medical image-based computational fluid dynamics (CFD) simulations can provide valuable insight into patient-specific hemodynamics and could potentially enhance personalized assessment of thrombus risk. However, the importance of accurately representing the left atrial (LA) wall dynamics has not been fully resolved. In this study, we compared four modeling scenarios; rigid walls, a generic wall motion based on a reference motion, a semi-generic wall motion based on patient-specific motion, and patient-specific wall motion based on medical images. We considered a LA geometry acquired from 4D computed tomography during AF, systematically performed convergence tests to assess the numerical accuracy of our solution strategy, and quantified the differences between the four approaches. The results revealed that wall motion had no discernible impact on LA cavity hemodynamics, nor on the markers that indicate thrombus formation. However, the flow patterns within the LAA deviated significantly in the rigid model, indicating that the assumption of rigid walls may lead to errors in the estimated risk factors. In contrast, the generic, semi-generic, and patient-specific cases were qualitatively similar. The results highlight the crucial role of wall motion on hemodynamics and predictors of thrombus formation, and also demonstrate the potential of using a generic motion model as a surrogate for the more complex patient-specific motion. While the present study considered a single case, the employed CFD framework is entirely open-source and designed for adaptability, allowing for integration of additional models and generic motions.

Investigating the importance of left atrial compliance on fluid dynamics in a novel mock circulatory loop

The left atrium (LA) hemodynamic indices hold prognostic value in various cardiac diseases and disorders. To understand the mechanisms of these conditions and to assess the performance of cardiac devices and interventions, in vitro models can be used to replicate the complex physiological interplay between the pulmonary veins, LA, and left ventricle. In this study, a comprehensive and adaptable in vitro model was created. The model includes a flexible LA made from silicone and allows distinct control over the systolic and diastolic functions of both the LA and left ventricle. The LA was mechanically matched with porcine LAs through expansion tests. Fluid dynamic measures were validated against the literature and pulmonary venous flows recorded on five healthy individuals using magnetic resonance flow imaging. Furthermore, the fluid dynamic measures were also used to construct LA pressure-volume loops. The in vitro pressure and flow recordings expressed a high resemblance to physiological waveforms. By decreasing the compliance of the LA, the model behaved realistically, elevating the a- and v-wave peaks of the LA pressure from 12 to 19 mmHg and 22 to 26 mmHg, respectively, while reducing the S/D ratio of the pulmonary venous flowrate from 1.5 to 0.3. This model provides a realistic platform and framework for developing and evaluating left heart procedures and interventions.

Electrophysiological evaluation of an anticancer drug gemcitabine on cardiotoxicity revealing down-regulation and modification of the activation gating properties in the human rapid delayed rectifier potassium channel

Gemcitabine is an antineoplastic drug commonly used in the treatment of several types of cancers including pancreatic cancer and non-small cell lung cancer. Although gemcitabine-induced cardiotoxicity is widely recognized, the exact mechanism of cardiac dysfunction causing arrhythmias remains unclear. The objective of this study was to electrophysiologically evaluate the proarrhythmic cardiotoxicity of gemcitabine focusing on the human rapid delayed rectifier potassium channel, hERG channel. In heterologous hERG expressing HEK293 cells (hERG-HEK cells), hERG channel current (IhERG) was reduced by gemcitabine when applied for 24 h but not immediately after the application. Gemcitabine modified the activation gating properties of the hERG channel toward the hyperpolarization direction, while inactivation, deactivation or reactivation gating properties were unaffected by gemcitabine. When gemcitabine was applied to hERG-HEK cells in combined with tunicamycin, an inhibitor of N-acetylglucosamine phosphotransferase, gemcitabine was unable to reduce IhERG or shift the activation properties toward the hyperpolarization direction. While a mannosidase I inhibitor kifunensine alone reduced IhERG and the reduction was even larger in combined with gemcitabine, kifunensine was without effect on IhERG when hERG-HEK cells were pretreated with gemcitabine for 24 h. In addition, gemcitabine down-regulated fluorescence intensity for hERG potassium channel protein in rat neonatal cardiomyocyte, although hERG mRNA was unchanged. Our results suggest the possible mechanism of arrhythmias caused by gemcitabine revealing a down-regulation of IhERG through the post-translational glycosylation disruption possibly at the early phase of hERG channel glycosylation in the endoplasmic reticulum that alters the electrical excitability of cells.

Predictors of Exercise Capacity in Dilated Cardiomyopathy with Focus on Pulmonary Venous Flow Recorded with Transesophageal Eco-Doppler

The aim of this study was to clarify the relative contribution of elevated left ventricle (LV) filling pressure (FP) estimated by pulmonary venous (PV) and mitral flow, transesophageal Doppler recording (TEE), and other extracardiac factors like obesity and renal insufficiency (KI) to exercise capacity (ExC) evaluated by cardiopulmonary exercise testing (CPX) in patients with dilated cardiomyopathy (DCM). During the CPX test, 119 patients (pts) with DCM underwent both peak VO2 consumption and then TEE with color-guided pulsed-wave Doppler recording of PVF and transmitral flow. In 78 patients (65%), peak VO2 was normal or mildly reduced (>14 mL/kg/min) (group 1) while it was markedly reduced (≤14 mL/kg/min) in 41 (group 2). In univariate analysis, systolic fraction (S Fract), a predictor of elevated pre-a LV diastolic FP, appeared to be the best diastolic parameter predicting a significantly reduced peak VO2. Logistic regression analysis identified five parameters yielding a unique, statistically significant contribution in predicting reduced ExC: creatinine clearance < 52 mL/min (odds ratio (OR) = 7.4, p = 0.007); female gender (OR = 7.1, p = 0.004); BMI > 28 (OR = 5.8, p = 0.029), age > 62 years (OR = 5.5, p = 0.03), S Fract < 59% (OR = 4.9, p = 0.02). Conclusion: KI was the strongest predictor of reduced ExC. The other modifiable factors were obesity and severe LV diastolic dysfunction expressed by blunted systolic venous flow. Contrarily, LV ejection fraction was not predictive, confirming other previous studies. This has important clinical implications.

Effects of the atrium on intraventricular flow patterns during mechanical circulatory support

Simulations of the ventricular flow patterns during left ventricular assist device (LVAD) support are mainly performed with idealized cylindrical inflow, neglecting the influence of the atrial vortex. In this study, the influence of the left atrium (LA) on the intra-ventricular flow was investigated via Computational Fluid Dynamics (CFD) simulations. Ventricular flow was simulated by a combined Eulerian (carrier flow)/Lagrangian (particles) approach taking into account either the LA or a cylindrical inflow section to mimic a fully support condition. The flow deviation at the mitral valve, the blood low-velocity volume as well as the residence time and shear stress history of the particles were calculated. Inclusion of the LA deflects the flow at the mitral valve by 25°, resulting in an asymmetric flow jet entering the left ventricle. This reduced the ventricular low-velocity volume by 40% (from 6.4 to 3.9 cm³), increased (40%) the shear stress experienced by particles and correspondingly increased (27%) their residence time. Under the studied conditions, the atrial geometry plays a major role in the development of intraventricular flow patterns. A reliable prediction of blood flow dynamics and consequently thrombosis risk analysis within the ventricle requires the consideration of the LA in computational simulations.

Prevalence, distribution, and determinants of pulmonary venous systolic flow reversal in severe mitral regurgitation

AIMS

This study aimed to evaluate the prevalence and distribution of pulmonary venous systolic flow reversal (PVSFR) in patients with severe mitral regurgitation (MR), and to examine the relationship between PVSFR profile and cardiac parameters.

METHODS AND RESULTS

A total of 125 patients with severe MR who had transoesophageal echocardiography (TOE) performed were reviewed. Of these, 121 (96.8%) patients showed all four pulmonary venous (PV) flows by TOE. They were categorized into three groups by the MR aetiology: degenerative MR (DMR) (n = 72), ventricular functional MR (V-FMR) (n = 20), and atrial functional MR (A-FMR) (n = 16). Eighteen (16.7%) patients had PVSFR in all four PVs. Twenty-nine (26.9%) had PVSFR in three PVs, 23 (21.3%) in two PVs, and 23 (21.3%) in one PV. PVSFR appeared at right PVs more frequently compared with left PVs. A high number of PVSFR was significantly correlated with higher pulmonary capillary wedge pressure (PCWP) and 3D vena contracta area (3D-VCA). With regard to MR aetiology, the number of PVSFRs was correlated with high 3D-VCA in patients with DMR and A-FMR, while it was correlated with high PCWP in patients with V-FMR. Laminar-type PVSFR appeared more frequently in FMR compared with DMR, and it had a relationship with higher PCWP and lower right ventricular fractional area change (RVFAC).

CONCLUSION

All four PV were detected in 96.8%, and 16.8% patients had PVSFR in all four PVs. PCWP and 3D-VCA were correlated with the number of PVSFRs in severe MR patients. Laminar-type PVSFR was related to higher PCWP and lower RVFAC.

Comprehensive data integration-Toward a more personalized assessment of diastolic function

BACKGROUND AND AIM

The main challenge of assessing diastolic function is the balance between clinical utility, in the sense of usability and time-efficiency, and overall applicability, in the sense of precision for the patient under investigation. In this review, we aim to explore the challenges of integrating data in the assessment of diastolic function and discuss the perspectives of a more comprehensive data integration approach.

METHODS

Review of traditional and novel approaches regarding data integration in the assessment of diastolic function.

RESULTS

Comprehensive data integration can lead to improved understanding of disease phenotypes and better relation of these phenotypes to underlying pathophysiological processes-which may help affirm diagnostic reasoning, guide treatment options, and reduce limitations related to previously unaddressed confounders. The optimal assessment of diastolic function should ideally integrate all relevant clinical information with all available structural and functional whole cardiac cycle echocardiographic data-envisioning a personalized approach to patient care, a high-reaching future goal in medicine.

CONCLUSION

Complete data integration seems to be a long-lasting goal, the way forward in diastology, and machine learning seems to be one of the tools suited for the challenge. With perpetual evidence that traditional approaches to complex problems may not the optimal solution, there is room for a steady and cautious, and inherently very exciting paradigm shift toward novel diagnostic tools and workflows to reach a more personalized, comprehensive, and integrated assessment of cardiac function.

Transesophageal echocardiographic evaluation of pulmonary vein diastolic wave deceleration time - As a predictor of left atrial pressure

Background:

The deceleration time of the pulmonary venous diastolic flow has been well-correlated with invasive pulmonary capillary wedge pressure in several studies regardless of left ventricular systolic function. This study was conducted to correlate deceleration time of pulmonary venous diastolic wave, DT_(D), and left atrial pressure (LAP), obtained noninvasively from mitral early diastolic inflow velocity-to-early diastolic mitral annulus velocity ratio (E/e′), and to assess the ease of each method in patients with coronary artery disease undergoing off-pump coronary artery bypass grafting (OPCAB) by transesophageal echocardiography.

Methods:

Forty-five adult patients with coronary artery disease, with left ventricular ejection fraction of ≥50% posted for elective OPCAB were enrolled in the study.

Results:

Forty values of LAP and DT_(D) were analyzed. A significant linear correlation (r = −0.64) was found between DT_(D) and LAP. Area under the curve of DT_(D) of ≤183 ms for predicting elevated LAP (>15) was 0.903 (95% confidence interval: 0.767 to 0.974, P < 0.0001).

Conclusion:

Deceleration time of pulmonary venous flow diastolic waveform, DT_(D), feasible promising echocardiographic measure in determining elevated LAP and DT_(D) ≤183 ms predicts elevated LAP.

Increased atrial contraction contribution to left ventricular filling during early septic shock

PURPOSE

To assess the atrial systolic function and the contribution of atrial contraction to left ventricular (LV) filling in septic shock patients as compared with healthy volunteers.

METHODS

Twenty-seven septic patients evaluated during first 48 h of ICU admission and compared with 27 healthy volunteers. Left atrial (LA) contraction contribution to LV filling was calculated as the active emptying atrial volume/LV end-diastolic volume. Atrial systolic function was evaluated with the atrial kinetic force [LAKE = 0.5 × blood density × LVV_active × (peak A velocity)²] and atrial ejection force [LASF = 0.5 × blood density × mitral annulus area × (peak A velocity)²].

RESULTS

LV ejection fraction was lower in septic patients than in control group: 51 ± 14%vs 60 ± 6% (p < 0.01). Contribution of LA contraction to LV preload was greater in septic patients than in normal subjects (26.7 ± 11.3% vs 15.9 ± 5.9%, p < 0.001), even if adjusted for age (0.49 ± 0.19 vs 0.35 ± 0.13, p = 0.004). LAKE and LASF were also significantly larger in septic patients than in normal subjects (21.8 ± 9.1 vs 7.3 ± 3 kdynes·cm, p < 0.001; 16.1 ± 11.7 vs 9.8 ± 4.3 kdynes, p = 0.048, respectively), and remained unchanged during the next 48 h.

CONCLUSION

In septic shock patients, LA systolic function increased and greatly contributed to support LV filling. These results highlight the role of preserving atrial contraction on the hemodynamic resuscitation in early septic shock.

Image-Based Flow Simulations of Pre- and Post-left Atrial Appendage Closure in the Left Atrium

PURPOSE

For patients with atrial fibrillation, the left atrial appendage (LAA) is often the site of thrombus formation due to low atrial ejection fraction that triggers strokes and other thromboembolic events. Recently introduced percutaneous LAA occlusion procedure is known to reduce LAA-induced strokes. Despite having the procedure, there are still 11% of the patients who continue to suffer from future strokes or transient ischemic attacks, not accounting for the procedural related complications. The high failure rate is largely due to the variabilities in LAA's shape, size, and contractility which may result in ineffectiveness of this procedure. To correctly identify the candidates and evaluate the effectiveness of the procedure, we rely on patient-specific CT scans which provides the exact LA and LAA geometries and predictive hemodynamic analysis to assist in evaluating quantitative flow parameters pre- and post-LAA occlusion procedures. Hemodynamic parameters are critical to predict adverse hemodynamic flow patterns in LAA as well as the effectiveness of LAA closure in individual patient. The aim of this paper is to establish an image-based patient-specific computational fluid dynamic (CFD) simulation framework specific to the prediction of treatment outcomes of LAA closure with atrial fibrillation. This framework utilizes automated LA/LAA image segmentation which yields significant reduction in image processing. One set of patient data with successful procedure outcome is used to illustrate the potential of the proposed framework.

METHODS

The proposed LAA occlusion simulation framework is composed of several components: (1) a novel image segmentation procedure, which is fully-automated to identify LA/LAA geometries from CT images, (2) a finite-element mesh generation procedure which transforms the surface geometry into a 3-D volume mesh and properly identified boundary planes, (3) performing CFD simulations with atrial fibrillation flow boundary conditions, and (4) analyzing flow characteristics (velocity, flow patterns, streamlines, vortices) within the LA for before and after LAA closure.

RESULTS

Based on the LA/LAA segmentation of a 65 year old female patient with chronic atrial fibrillation, a CFD analysis was pursued to examine flow characteristics upon LAA closure. The results showed that the flow velocity magnitudes were significantly reduced by a maximum factor of 2.21, flow streamlines were greatly stabilized, and mitral outflow appeared to be more organized. Vortices were dramatically reduced in size, number, intensity, as well as duration. During diastole, the peak vortex diameter was reduced from 2.8 to 1.5 cm, while the vortex duration was reduced from 0.210 to 0.135 s. These flow characteristics all indicated a reduced risk in future thrombus formation and strokes based on the established relationship between flow and thrombus formation. For the patient case under study, the effectiveness of the procedure is predicted and found to be consistent with the actual procedural outcome.

CONCLUSIONS

This framework successfully predicted patient-specific outcome of a LAA closure procedure for one patient with atrial fibrillation. It can be further developed into a useful tool for pre-procedural planning and candidate selection. More patient data are necessary for further validation studies.

Relation Between Pulmonary Venous Flow and Left Atrial Pressure During Percutaneous Mitral Valve Repair With the MitraClip

Pulmonary venous (PV) flow may provide valuable information in terms of the severity of mitral regurgitation and left atrial (LA) pressure. We sought to find PV flow determinants of LA pressure during MitraClip procedure. We analyzed 575 PV flows in 290 patients using transesophageal echocardiography before and after MitraClip procedure. We measured peak systolic velocity (Sv), diastolic velocity (Dv), systolic velocity time integral (Svti), diastolic velocity time integral (Dvti), and those systolic to diastolic ratio as PV flow parameters. Systolic PV flow velocity was lower than diastolic PV flow velocity before the procedure, but systolic PV flow velocity markedly increased after the procedure. Peak Sv/Dv ratio and Svti/Dvti ratio after the procedure were significantly higher than those before the procedure (peak Sv/Dv; 1.06 [inter-quartile range (IQR) 0.73 to 1.34] vs 0.32 [IQR 0.03 to 0.55], p <0.001, Svti/Dvti; 1.06 [IQR 0.76 to 1.61] vs 0.26 [IQR 0.02 to 0.51], p <0.001). Peak Sv/Dv ratio and Svti/Dvti ratio were negatively correlated with mean LA pressure and LA pressure V wave, respectively (peak Sv/Dv ratio; r = -0.50 and r = -0.59, Svti/Dvti ratio; r = -0.47 and r = -0.58, p <0.001). In receiver operating characteristics curve assessing the ability of PV flow to predict mean LA pressure ≥20 mm Hg after the successful procedure, the area under the curve of peak Sv/Dv ratio was 0.76 (p <0.001). Peak Sv/Dv ratio <0.98 best predicted LA pressure ≥20 mm Hg with 77% sensitivity and 71% specificity. In conclusion, systolic PV flow velocity immediately increased in response to mitral regurgitation reduction during MitraClip procedure. PV flow velocity, specifically systolic to diastolic ratio, was useful to evaluate invasively determined LA pressure.

Association of left ventricular myocardial dysfunction with diabetic polyneuropathy

BACKGROUND

The pathogenesis of left ventricular (LV) dysfunction in diabetes has been attracting attention. It has been reported that LV longitudinal systolic myocardial function determined by speckle tracking echocardiography (STE) is associated with diabetic polyneuropathy (DPN). However, the relationship between the severity of peripheral neuropathy and LV myocardial dysfunction is unknown. This study examined the relationship between the severity of DPN and echocardiographic parameters as well as clinical features.

METHODS

The subjects were 166 patients (57 ± 14 years old) with diabetes who had a normal LV ejection fraction (≥ 55%). To assess LV longitudinal systolic function, global longitudinal strain (GLS) was calculated by two-dimensional STE as the average peak strain of 18 LV segments in three standard apical views. A nerve conduction study (NCS) was performed in each subject to assess the severity of neuropathy based on the NCS Baba Classification (Grade 0: no apparent abnormalities-Grade IV: abolition). Three nerves in the lower extremity were examined: tibial nerve (F-wave latency, motor nerve conduction velocity, and amplitude), sural nerve (sensory conduction velocity and amplitude), and peroneal nerve (motor nerve conduction velocity and amplitude).

RESULTS

Of the 166 subjects, 112 subjects (67.5%) were confirmed to have DPN, and all the subjects were divided into two groups according to the presence/absence of DPN. When multivariate analysis was performed using significant factors from univariate logistic regression analysis as explanatory variables, GLS was found to be an independent determinant of DPN (odds ratio: 0.55, p < 0.001). In multivariate analysis of NCS data, F-wave latency was the most important determinant of DPN (odds ratio: 1.43, p < 0.001). There was a significant negative correlation between F-wave latency and GLS (r = - 0.43, p < 0.001). Regarding the relation between GLS and the severity of DPN, GLS was significantly lower in patients with Grade I or higher DPN than in patients without DPN, but showed no significant difference between the grades of neuropathy. In addition, GLS was significantly lower when 2-3 lower extremity nerves were affected by DPN than in patients without DPN.

CONCLUSION

Patients with diabetes may already have subclinical LV myocardial dysfunction when DPN is Grade I. Assessment of LV longitudinal systolic function by GLS may be important in diabetic patients with DPN.

Monitoring Changes in Hepatic Venous Velocities Flow after a Fluid Challenge Can Identify Shock Patients Who Lack Fluid Responsiveness

Background:

Evaluating the hemodynamic status and predicting fluid responsiveness are important in critical ultrasound assessment of shock patients. Transthoracic echocardiography with noninvasive diagnostic parameters allows the assessment of volume responsiveness. This study aimed to assess the hemodynamic changes in the liver and systemic hemodynamic changes during fluid challenge and during passive leg raising (PLR) by measuring hepatic venous flow (HVF) velocity.

Methods:

This is an open-label study in a tertiary teaching hospital. Shock patients with hypoperfusion who required fluid challenge were selected for the study. Patients <18 years old and those with contraindications to PLR were excluded from the study. Baseline values were measured, PLR tests were performed, and 500 ml of saline was infused over 30 min. Parameters associated with cardiac output (CO) in the left ventricular outflow tract were measured using the Doppler method. In addition, HVF velocity and right ventricular function parameters were determined.

Results:

Middle hepatic venous (MHV) S-wave velocity was positively correlated in all patients with CO at baseline (r = 0.706, P < 0.01) and after volume expansion (r = 0.524, P = 0.003). CO was also significantly correlated with MHV S-wave velocity in responders (r = 0.608, P < 0.01). During PLR, however, hepatic venous S-wave velocity did not correlate with CO. For the parameter ΔMHV D (increase in change in MHV D-wave velocity after volume expansion), defined as (MHV D_afterVE − MHV D_Baseline)/MHV D_Baseline × 100%, >21% indicated no fluid responsiveness, with a sensitivity of 100%, a specificity of 71.2%, and an area under the receiver operating characteristic curve of 0.918.

Conclusions:

During fluid expansion, hepatic venous S-wave velocity can be used to monitor CO, whether or not it is increasing. ΔMHV D ≥21% indicated a lack of fluid responsiveness, thus helping to decide when to stop infusions.

Chagas cardiomyopathy: The potential effect of benznidazole treatment on diastolic dysfunction and cardiac damage in dogs chronically infected with Trypanosoma cruzi

Cardiac involvement represents the main cause of mortality among patients with Chagas disease, and the relevance of trypanocidal treatment to improving diastolic dysfunction is still doubtful. In the present study, we used a canine model infected with the benznidazole-sensitive Berenice-78 Trypanosoma cruzi strain to verify the efficacy of an etiologic treatment in reducing the parasite load and ameliorating cardiac muscle tissue damage and left ventricular diastolic dysfunction in the chronic phase of the infection. The effect of the treatment on reducing the parasite load was monitored by blood PCR and blood culture assays, and the effect of the treatment on the outcome of heart tissue damage and on diastolic function was evaluated by histopathology and echo Doppler cardiogram. The benefit of the benznidazole-treatment in reducing the parasite burden was demonstrated by a marked decrease in positive blood culture and PCR assay results until 30days post-treatment. At this time, the PCR and blood culture assays yielded negative results for 82% of the treated animals, compared with only 36% of the untreated dogs. However, a progressive increase in the parasite load could be detected in the peripheral blood for one year post-treatment, as evidenced by a progressive increase in positive results for both the PCR and the blood culture assays at follow-up. The parasite load reduction induced by treatment was compatible with the lower degree of tissue damage among animals euthanized in the first month after treatment and with the increased cardiac damage after this period, reaching levels similar to those in untreated animals at the one-year follow-up. The two infected groups also presented similar, significantly smaller values for early tissue septal velocity (E' SIV) than the non-infected dogs did at this later time. Moreover, in the treated animals, an increase in the E/E' septal tissue filling pressure ratio was observed when compared with basal values as well as with values in non-infected dogs. These findings strongly suggest that the temporary reduction in the parasite load that was induced by benznidazole treatment was not able to prevent myocardial lesions and diastolic dysfunction for long after treatment.

Diastolic dysfunction in the critically ill patient

Left ventricular diastolic dysfunction is a common finding in critically ill patients. It is characterized by a progressive deterioration of the relaxation and the compliance of the left ventricle. Two-dimensional and Doppler echocardiography is a cornerstone in its diagnosis. Acute pulmonary edema associated with hypertensive crisis is the most frequent presentation of diastolic dysfunction critically ill patients. Myocardial ischemia, sepsis and weaning failure from mechanical ventilation also may be associated with diastolic dysfunction. The treatment is based on the reduction of pulmonary congestion and left ventricular filling pressures. Some studies have found a prognostic role of diastolic dysfunction in some diseases such as sepsis. The present review aims to analyze thoroughly the echocardiographic diagnosis and the most frequent scenarios in critically ill patients in whom diastolic dysfunction plays a key role.

Cardiac Imaging to Evaluate Left Ventricular Diastolic Function

Left ventricular diastolic dysfunction in clinical practice is generally diagnosed by imaging. Recognition of heart failure with preserved ejection fraction has increased interest in the detection and evaluation of this condition and prompted an improved understanding of the strengths and weaknesses of different imaging modalities for evaluating diastolic dysfunction. This review briefly provides the pathophysiological background for current clinical and experimental imaging parameters of diastolic dysfunction, discusses the merits of echocardiography relative to other imaging modalities in diagnosing and grading diastolic dysfunction, summarizes lessons from clinical trials that used parameters of diastolic function as an inclusion criterion or endpoint, and indicates current areas of research.

Left Atrial Function in Patients with Chronic Chagasic Cardiomyopathy

BACKGROUND

Chagas disease is a cause of dilated cardiomyopathy, and information about left atrial (LA) function in this disease still lacks.

OBJECTIVE

To assess the different LA functions (reservoir, conduit and pump functions) and their correlation with the echocardiographic parameters of left ventricular (LV) systolic and diastolic functions.

METHODS

10 control subjects (CG), and patients with Chagas disease as follows: 26 with the indeterminate form (GI); 30 with ECG alterations (GII); and 19 with LV dysfunction (GIII). All patients underwent M-mode and two-dimensional echocardiography, pulsed-wave Doppler and tissue Doppler imaging.

RESULTS

Reservoir function (Total Emptying Fraction: TEF): (p <0.0001), lower in GIII as compared to CG (p = 0.003), GI (p <0.001) and GII (p <0.001). Conduit function (Passive Emptying Fraction: PEF): (p = 0.004), lower in GIII (GIII and CG, p = 0.06; GI and GII, p = 0.06; and GII and GIII, p = 0.07). Pump function (Active Emptying Fraction: AEF): (p = 0.0001), lower in GIII as compared to CG (p = 0.05), GI (p<0.0001) and GII (p = 0.002). There was a negative correlation of E/e' (average) with the reservoir and pump functions (TEF and AEF), and a positive correlation of e' (average) with s' wave (both septal and lateral walls) and the reservoir, conduit and pump LA functions.

CONCLUSION

An impairment of LA functions in Chagas cardiomyopathy was observed.

Right Ventricular Depression After Cardiopulmonary Bypass for Valvular Surgery

OBJECTIVE

To assess if right ventricular (RV) dysfunction is associated with increased mortality after cardiac surgery.

DESIGN

Post-hoc analysis of a single-center double-blind randomized controlled trial.

SETTING

University hospital.

PARTICIPANTS

A total of 120 patients undergoing simple or complex valvular surgery.

INTERVENTIONS

Patients were randomized to receive intravenous amiodarone or placebo intraoperatively. As secondary analysis, patients were divided into those requiring or not requiring postoperative inotropic agents.

MEASUREMENTS AND MAIN RESULTS

After cardiopulmonary bypass (CPB), there were significant increases in heart rate, cardiac index, systolic and mean arterial pressures, central venous pressure and pulmonary capillary wedge pressure with reduction in systemic vascular resistance (p<0.05). Right ventricular end-systolic area became larger in those without inotropes and tricuspid annular plane systolic excursion was reduced in all patients; mitral annular systolic velocities were higher in patients receiving inotropes. Both right- and left-sided Doppler signals were altered significantly after CPB, which may be attributed to increased filling pressure. Inotropic agents were required in 56 patients after CPB (47%). The use of inotropic agents was associated with increased left and right atrial velocities (p<0.05). There were no differences in postoperative complications between groups; however, the number of deaths at 6 years was increased in patients who received inotropes after CPB (p = 0.0247).

CONCLUSIONS

The increases in right-sided dimensions after CPB are associated with reduction in RV function and increased biventricular filling pressure, suggesting worsening biventricular function and interventricular dependence. Inotropic medications were associated with unaltered RV dimensions and increased biatrial activity.

A novel ultrasound predictor of pulmonary capillary wedge pressure assessed by the combination of left atrial volume and function: A speckle tracking echocardiography study

BACKGROUND

We hypothesized that a development of a novel index based on the combination of left atrial volume (LAV) and left atrial (LA) function evaluated by the time-LA volume curve using speckle tracking echocardiography (STE) would be accurate and useful to estimate pulmonary capillary wedge pressure (PCWP). Our goal was to develop a novel index of PCWP based on a combination of LAV and LA function using STE.

METHODS

A cross-validation study was performed with the patients divided into a training study to define the novel index (n=50) and a testing study to validate the index (n=196). PCWP was measured by right heart catheterization, and phasic LAV and emptying function (EF) were measured by STE.

RESULTS

Simple linear regression analysis in the training study revealed that the novel index that best estimated PCWP was the kinetics-tracking index [KT index=log10 (active LAEF/minimum LAV index)]. Multiple regression analysis revealed that the KT index was the most reliable predictor of PCWP. It had the strongest correlation with PCWP (r=-0.86, p<0.001) among all echocardiographic parameters. In the testing study, PCWP estimated by the KT index was also strongly correlated with measured PCWP (r=0.92, p<0.001). These correlations were also strong in the patients with reduced left ventricular ejection fraction (<50%), chronic heart failure, and chronic atrial fibrillation (r=0.92, r=0.91, r=0.79, p<0.001, respectively).

CONCLUSIONS

A novel index (KT index) using a combination of LAV and LA function was a powerful and useful predictor of PCWP and may be valuable in routine clinical practice.

Numerical analysis of hemodynamic changes in the left atrium due to atrial fibrillation

Atrial fibrillation (AF) disrupts movement of the left atrium (LA) and worsens the vital prognosis by causing thromboembolism. Ultrasound Doppler measurement, phase-contrast magnetic resonance imaging (PC MRI), as well as computational fluid dynamics (CFD) have revealed hemodynamic changes in the LA due to AF, such as stagnation of blood flow in the left atrial appendage (LAA). However, quantitative evaluation of the hemodynamics during AF has not been conducted, and the effects of important AF characteristics, such as a lack of active contraction of the LA (atrial kick) in late diastole and the occurrence of high-frequency fibrillation (>400bpm) of the atrial wall, on blood flow field and concomitant hemodynamic stresses have not been completely understood. In this study, the effects of the above-mentioned two characteristic phenomena of AF on blood flow and hemodynamic parameters were quantitatively investigated. Based on MRI of a healthy volunteer heart, one healthy LA model and two AF models (one without atrial kick, and one without atrial kick and with high-frequency fibrillation) were constructed to perform hemodynamic analysis, and the computational results were compared. The results revealed that each characteristic phenomenon of AF influenced hemodynamics. Especially, atrial wall movement by high-frequency fibrillation had a large impact on the stagnation of blood flow. The relative residence time (RRT), which is an indicator of stagnation of blood flow, increased in the upper part of the LAA during AF. This result implies that there is a local thrombus-prone site in LAA when AF occurs.

Interatrial septum motion but not Doppler assessment predicts elevated pulmonary capillary wedge pressure in patients undergoing cardiac surgery

BACKGROUND

Left atrial pressure and its surrogate, pulmonary capillary wedge pressure (PCWP), are important for determining diastolic function. The role of transthoracic echocardiography (TTE) in assessing diastolic function is well established in awake subjects. The objective was to assess the accuracy of predicting PCWP by TTE and transesophageal echocardiography (TEE) during coronary artery surgery.

METHODS

In 27 adult patients undergoing on-pump coronary artery surgery, simultaneous echocardiographic and hemodynamic measurements were obtained immediately before anesthesia (TTE), after anesthesia and mechanical ventilation (TTE and TEE), during conduit harvest (TEE), and after separation from cardiopulmonary bypass (TEE).

RESULTS

Twenty patients had an ejection fraction (EF) of 0.5 or greater. With the exception of E/e' and S/D ratios, echocardiographic values changed over the echocardiographic studies. In patients with low EF, E velocity, deceleration time, pulmonary vein D, S/D, and E/e' ratios correlated well with PCWP before anesthesia. After induction of anesthesia using TTE or TEE, correlations were poor. In normal EF patients, correlations were poor for both TEE and TTE at all five stages. The sensitivity and specificity of echocardiographic values were not high enough to predict raised PCWP except for a fixed curve pattern of interatrial septum (area under the curve 0.89 for PCWP ≥ 17, and 0.98 for ≥ 18 mmHg) and S/D less than 1 (area under the curve 0.74 for PCWP ≥ 17, and 0.78 for ≥ 18 mmHg).

CONCLUSION

Doppler assessment of PCWP was neither sensitive nor specific enough to be clinically useful in anesthetized patients with mechanical ventilation. The fixed curve pattern of the interatrial septum was the best predictor of raised PCWP.

Acute intraoperative effect of intravenous amiodarone on right ventricular function in patients undergoing valvular surgery

BACKGROUND

Amiodarone is commonly used in the acute care setting. However the acute hemodynamic and echocardiographic effect of intravenous amiodarone administered intraoperatively on right ventricular (RV) systolic and diastolic function using transesophageal echocardiography (TEE) has not been described.

METHODS

The study design was a randomized controlled trial in elective cardiac surgical patients undergoing valvular surgery. Patients received an intravenous loading dose of 300 mg of either amiodarone or placebo in the operating room, followed by an infusion of 15 mg/kg for two days. Hemodynamic profiles, echocardiographic measurement of RV and left ventricular (LV) dimensions, Doppler interrogation of tricuspid and mitral valve, hepatic and pulmonary venous flow combined with tissue Doppler imaging of the tricuspid and mitral valve annulus were obtained before and after bolus.

RESULTS

Although more patients in the placebo group had chronic obstructive lung disease (14 vs 6, p=0.05) and diabetes (14 vs 5; p=0.0244), there was no difference in terms of baseline hemodynamic, 2D and Doppler variables. After bolus, a significant increase in pulmonary artery pressure, central venous pressure and pulmonary vascular resistance index (p<0.05) was observed in the amiodarone group with reduction in systolic to diastolic (S/D) ratio of the hepatic (p=0.0247) and pulmonary venous (p=0.0052) velocity.

CONCLUSION

Acute administration of amiodarone is associated with alteration in RV diastolic properties and has minimal negative inotropic effect on RV systolic function in cardiac surgical patients with valvular disease.

Tissue doppler myocardial performance index in patients with heart failure and its relationship with haemodynamic parameters

The myocardial performance index (MPI) reflects both the systolic and diastolic function of the heart, and is easily applied in practice. In this study, we aimed to determine the relationship between MPI and invasive haemodynamic parameters in heart failure patients. A total of 126 patients with heart failure were selected, all of whom were referred for diagnostic cardiac catheterisation, and were divided into two groups. Group I consisted of 59 patients (32 men and 27 women, mean age 61 ± 10; functional capacity New York Heart Association (NYHA) Class I; and left ventricular end-diastolic pressure (LVEDP) <16 mmHg). Group II included 67 patients (34 men and 33 women, mean age 60 ± 9; NYHA Class ≥ II; LVEDP ≥ 16 mmHg). The following parameters were measured in all patients: ejection fraction with Simpson method, the peak mitral early (E) and late (A) diastolic velocities, E/A ratio, deceleration time (DT) and tissue Doppler from four different areas of the mitral annulus (septum, lateral, inferior and anterior). In order to measure MPI with two methods (standard Doppler and tissue Doppler), isovolumetric contraction time (IVCT), isovolumetric relaxation time (IVRT) and ejection time (ET) were measured from four areas and mean values of MPI were calculated. There was no difference between the two groups in E/A ratios, DT and IVRT (p > 0.05). Group II patients had longer IVCT and ET, when compared with group I patients (p < 0.05). MPI, measured by both standard pulsed wave Doppler and tissue Doppler methods, was significantly higher in group II patients, when compared with the values obtained from group I patients (Group I: 0.50 ± 0.2 and 0.50 ± 0.14; group II: 0.98 ± 0.3 and 1.2 ± 0.32; p < 0.001). According to receiver operating characteristics curve analysis, the cut-off value for MPI measured by tissue Doppler was 0.74. The sensitivity and specificity of this value were measured as 92.5 and 91.5%, respectively. MPI measured by standard Doppler method was 0.67, and its sensitivity and specificity were 85.1 and 83.1%, respectively. We found a strong relationship between MPI and LVEDP (r = 0.83, p < 0.001; r = 0.96, p < 0.001), especially when measured by tissue Doppler. In addition, we observed a significant relationship between the MPI values measured by tissue Doppler and those measured by standard traditional methods (r = 0.85, p < 0.001). We showed that MPI was reliable for the evaluation of global cardiac functions in patients with heart failure, as measured with both pulsed-wave Doppler and tissue Doppler. We assert that, in order to differentiate between those patients with symptomatic heart failure from the asymptomatic cases, MPI as measured with the tissue Doppler method is an improvement on MPI as measured using traditional methods.

Role of echocardiography in the contemporary management of chronic heart failure

Echocardiography is an excellent noninvasive tool for the assessment of ventricular size and both systolic and diastolic function, and it is routinely used in patients with heart failure. This review will discuss the role of echocardiography in heart failure diagnosis, prognostic assessment and in the management of heart failure patients.

Pulmonary venous flow index as a predictor of pulmonary vascular resistance variability in congenital heart disease with increased pulmonary flow: a comparative study before and after oxygen inhalation

AIMS

There is no definitive and reliable echocardiographic method for estimating the pulmonary vascular resistance (PVR) to differentiate persistent vascular disease from dynamic pulmonary hypertension. The aim of this study was to analyze the relationship between the pulmonary venous blood flow velocity-time integral (VTIpv) and PVR.

METHODS AND RESULTS

Eighteen patients (10 females; 4 months to 22 years of age) with congenital heart disease and left to right shunt were studied. They underwent complete cardiac catheterization, including measurements of the PVR and Qp:Qs ratio, before and after 100% oxygen inhalation. Simultaneous left inferior pulmonary venous flow VTIpv was obtained by Doppler echocardiography. The PVR decreased significantly from 5.0 ± 2.6 W to 2.8 ± 2.2 W (P = 0.0001) with a significant increase in the Qp:Qs ratio, from 3.2 ± 1.4 to 4.9 ± 2.4 (P = 0.0008), and the VTIpv increased significantly from 22.6 ± 4.7 cm to 28.1 ± 6.2 cm (P = 0.0002) after 100% oxygen inhalation. VTIpv correlated well with the PVR and Qp:Qs ratio (r = -0.74 and 0.72, respectively). Diagnostic indexes indicated a sensitivity of 86%, specificity of 75%, accuracy of 83%, a positive predictive value of 92% and a negative predictive value of 60%.

CONCLUSION

The VTIpv correlated well with the PVR. The measurement of this index before and after oxygen inhalation may become a useful noninvasive test for differentiating persistent vascular disease from dynamic and flow-related pulmonary hypertension.

Transthoracic echocardiographic parameters in the estimation of pulmonary capillary wedge pressure in patients with present or previous heart failure

Multiple echocardiographic criteria are routinely used for the estimation of left heart filling pressures. We assessed the predictive value of various echocardiographic parameters to estimate the left heart filling pressure and proposed a simplified approach for its evaluation. We collected the clinical, echocardiographic, and invasive hemodynamic data from 93 patients with heart failure who underwent right-sided heart catheterization and transthoracic echocardiography within a 24-hour period. Of these 93 patients, 57% had a left ventricular ejection fraction <50% and 69% had an elevated mean pulmonary capillary wedge pressure of ≥ 15 mm Hg. A mitral E/E' of ≥ 15 had a sensitivity of 55% but a specificity of 96%. A left atrial area of ≥ 20 cm(2) had a sensitivity of 66% and specificity of 89%. A deceleration time <140 ms had a sensitivity of 51% and specificity of 93% to predict a pulmonary capillary wedge pressure of ≥ 15 mm Hg. The combination of E/E' ≥ 15 ± left atrial area of ≥ 20 cm(2) ± deceleration time <140 ms provided a sensitivity of 92% and specificity of 85%. On multivariate analysis, the combination of E/E' ≥ 15, left atrial area of ≥ 20 cm(2), and deceleration time <140 ms was the most significant predictor of a pulmonary capillary wedge pressure of ≥ 15 mm Hg (odds ratio 48, 95% confidence interval 10 to 289, p <0.001). In conclusion, this simplified approach using 3 echocardiographic parameters provides an accurate and a practical approach for the routine estimation of the elevated left heart filling pressure.

Abnormal early diastolic intraventricular flow 'kinetic energy index' assessed by vector flow mapping in patients with elevated filling pressure

AIMS

Recently developed vector flow mapping (VFM) enables evaluation of local flow dynamics without angle dependency. This study used VFM to evaluate quantitatively the index of intraventricular haemodynamic kinetic energy in patients with left ventricular (LV) diastolic dysfunction and to compare those with normal subjects.

METHODS AND RESULTS

We studied 25 patients with estimated high left atrial (LA) pressure (pseudonormal: PN group) and 36 normal subjects (control group). Left ventricle was divided into basal, mid, and apical segments. Intraventricular haemodynamic energy was evaluated in the dimension of speed, and it was defined as the kinetic energy index. We calculated this index and created time-energy index curves. The time interval from electrocardiogram (ECG) R wave to peak index was measured, and time differences of the peak index between basal and other segments were defined as ΔT-mid and ΔT-apex. In both groups, early diastolic peak kinetic energy index in mid and apical segments was significantly lower than that in the basal segment. Time to peak index did not differ in apex, mid, and basal segments in the control group but was significantly longer in the apex than that in the basal segment in the PN group. ΔT-mid and ΔT-apex were significantly larger in the PN group than the control group. Multiple regression analysis showed sphericity index, E/E' to be significant independent variables determining ΔT apex.

CONCLUSION

Retarded apical kinetic energy fluid dynamics were detected using VFM and were closely associated with LV spherical remodelling in patients with high LA pressure.

Perioperative assessment of diastolic dysfunction

Assessment of diastolic function should be a component of a comprehensive perioperative transesophageal echocardiographic examination. Abnormal diastolic function exists in >50% of patients presenting for cardiac and high-risk noncardiac surgery, and has been shown to be an independent predictor of adverse postoperative outcome. Normalcy of systolic function in 50% of patients with congestive heart failure implicates diastolic dysfunction as the probable etiology. Comprehensive evaluation of diastolic function requires the use of various, load-dependent Doppler techniques This is further complicated by the additional effects of dehydration and anesthetic drugs on myocardial relaxation and compliance as assessed by these Doppler measures. The availability of more sophisticated Doppler techniques, e.g., Doppler tissue imaging and flow propagation velocity, makes it possible to interrogate left ventricular diastolic function with greater precision, analyze specific stages of diastole, and to differentiate abnormalities of relaxation from compliance. Additionally, various Doppler-derived ratios can be used to estimate left ventricular filling pressures. The varying hemodynamic environment of the operating room mandates modification of the diagnostic algorithms used for ambulatory cardiac patients when left ventricular diastolic function is evaluated with transesophageal echocardiography in anesthetized surgical patients.

CMR for Assessment of Diastolic Function

Prevalence of heart failure with preserved left ventricular ejection fraction amounts to 50% of all cases with heart failure. Diagnosis assessment requires evidence of left ventricular diastolic dysfunction. Currently, echocardiography is the method of choice for diastolic function testing in clinical practice. Various applications are in use and recommended criteria are followed for classifying the severity of dysfunction. Cardiovascular magnetic resonance (CMR) offers a variety of alternative applications for evaluation of diastolic function, some superior to echocardiography in accuracy and reproducibility, some being complementary. In this article, the role of the available CMR applications for diastolic function testing in clinical practice and research is reviewed and compared to echocardiography.

Diastolic dysfunction and abnormal exercise ventilation predict adverse outcome in elderly patients with chronic systolic heart failure

BACKGROUND

Heart failure is increasing in the elderly and represents a socioeconomic burden requiring the correct management for which risk stratification is mandatory. Among younger patients, echocardiogram and cardiopulmonary exercise test are useful in prognostic stratification. Few studies have analyzed the utility of these tests in elderly patients.

METHODS

We report on 90 patients over 70 years old, on whom cardiopulmonary tests and echocardiograms were performed between 1998 and 2006 (67 M, 23 F; 75 ± 3 years; ejection fraction (EF) 30 ± 6%; NYHA 2.1 ± 0.8; 60% ischemic; therapy according to international guidelines). Echocardiographic variables were (1) left ventricular ejection fraction (EF); (2) severity of diastolic dysfunction on multiparametric examination of Doppler and TDI parameters; (3) severity of functional mitral regurgitation. Cardiopulmonary variables were (1) peak VO(2); (2) peak O(2) pulse; (3) peak respiratory quotient (RQ); (4) VE/VCO(2) slope. Endpoint considered was mortality of any cause at three-years follow-up.

RESULTS

Mortality was 21%. At univariate analysis, survivors (n = 71) and deceased (n = 19) were similar for age, NYHA class, peakVO(2) and RQ; they differed for EF, severity of mitral regurgitation, severity of diastolic dysfunction, O(2) pulse and VE/VCO(2) slope. At multivariate analysis, only VE/VCO(2) slope and severe diastolic dysfunction (restrictive filling pattern) discriminated between the two groups. In particular, the association of restrictive filling pattern and VE/VCO(2) slope ≥ 45 predicted 3-year mortality with sensitivity of 84% and specificity of 88%.

CONCLUSIONS

Echocardiographic and cardiopulmonary data can identify high-risk elderly patients with systolic heart failure, who may need aggressive clinical management.

Physiopathologic correlates of intrathoracic impedance in chronic heart failure patients

BACKGROUND

Increased plasma levels of amino-terminal fraction of brain natriuretic peptide (NT-proBNP) and alterations of diastolic filling as described by Doppler transmitral flow pattern are well-known markers of decompensated heart failure (HF). Recently, some implantable defibrillators have allowed monitoring of intrathoracic impedance, which is related to lung water content, potentially indicating HF deterioration. The aim of this study was to assess the correlation between intrathoracic impedance and NT-proBNP and echo-Doppler transmitral flow indexes.

METHODS

Data were collected from 111 HF patients, in six Italian centers. All patients were on optimal medical therapy. Device diagnostics, echographic data, NT-proBNP determination, and clinical status as assessed by the Heart Failure Score (HFS) were registered at baseline, at bimonthly visits, and at unscheduled examinations due to HF decompensation or device alerts.

RESULTS

Over a median follow-up of 413 days, 955 examinations were performed. Intrathoracic impedance was significantly correlated with NT-proBNP (P = 0.013) and with mitral E-wave deceleration time (DtE) (P = 0.017), but not with HFS. At the time of confirmed alert events, NT-proBNP was significantly higher than during confirmed nonalert event examinations; DtE did not differ, whereas impedance was significantly lower.

CONCLUSION

A decrease in intrathoracic impedance is inversely correlated with NT-proBNP and directly correlated with DtE. Intrathoracic impedance monitoring therefore has the physiologic basis for being a useful tool to identify early HF decompensation.

Transthoracic bioimpedance and brain natriuretic peptide levels accurately indicate additional diastolic dysfunction in patients with chronic advanced systolic heart failure

AIMS

Diastolic dysfunction in patients with heart failure has prognostic relevance, possibly because of its relationship with worsening haemodynamic status. In the quest for simpler indexes of haemodynamic status in patients, brain natriuretic peptide (BNP) levels have been proposed as a surrogate of diastolic function. To date, the value of combining BNP levels with non-invasive haemodynamic monitoring by transthoracic electric bioimpedance (TEB) for the prediction of diastolic function has not been evaluated.

METHODS AND RESULTS

We compared left ventricular diastolic function measured by tissue Doppler imaging (TDI) with TEB results and BNP levels in 120 patients with chronic advanced systolic heart failure on optimal treatment (70 +/- 9 years, NYHA 2.4 +/- 0.8, ejection fraction 31 +/- 5%). Of the TEB variables measured, we only considered thoracic fluid content (TFC). To describe diastolic function, we used the TDI of the velocity of displacement of the mitral annulus (E') and the ratio E/E'. In all patients, E/E' was significantly related to TFC and to BNP levels (P < 0.001). Moreover, the combination of BNP > or = 350 pg/mL and TFC > or = 35/kOmega identified patients with diastolic dysfunction (defined as E/E' > or = 15) with high sensitivity and specificity (95 and 94%, respectively).

CONCLUSION

The combination of transthoracic bioimpedance monitoring and BNP measurement accurately indicated the presence of diastolic dysfunction in most patients. These user-friendly and operator-independent tools may be useful as a screening assessment for diastolic dysfunction, and consequently abnormal central haemodynamic status, either in ambulatory patients or when an adequate echocardiographic evaluation is not readily available.

Effects of phlebotomy and phenylephrine infusion on portal venous pressure and systemic hemodynamics during liver transplantation

BACKGROUND

A regimen of fluid restriction, phlebotomy, vasopressors, and strict, protocol-guided product replacement has been associated with low blood product use during orthotopic liver transplantation. However, the physiologic basis of this strategy remains unclear. We hypothesized that a reduction of intravascular volume by phlebotomy would cause a decrease in portal venous pressure (PVP), which would be sustained during subsequent phenylephrine infusion, possibly explaining reduced bleeding. Because phenylephrine may increase central venous pressure (CVP), we questioned the validity of CVP as a correlate of cardiac filling in this context and compared it with other pulmonary artery catheter and transesophageal echocardiography-derived parameters. In particular, because optimal views for echocardiographic estimation of preload and stroke volume are not always applicable during liver transplantation, we evaluated the use of transmitral flow (TMF) early peak (E) velocity as a surrogate.

METHODS

In study 1, the changes in directly measured PVP and CVP were recorded before and after phlebotomy and phenylephrine infusion in 10 patients near the end of the dissection phase of liver transplantation. In study 2, transesophageal echocardiography-derived TMF velocity in early diastole was measured in 20 patients, and the changes were compared with changes in CVP, pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), cardiac output (CO), and calculated systemic vascular resistance (SVR) at the following times: postinduction, postphlebotomy, preclamping of the inferior vena cava, during clamping, and postunclamping.

RESULTS

Phlebotomy decreased PVP along with CO, PAP, PCWP, CVP, and TMF E velocity. Phenylephrine given after phlebotomy increased CVP, SVR, and arterial blood pressure but had no significant effect on CO, PAP, PCWP, or PVP. The change in TMF E velocity correlated well with the change in CO (Pearson correlation coefficient 95% confidence interval 0.738-0.917, P< or =0.015) but less well with the change in PAP (0.554-0.762, P< or =0.012) and PCWP (0.576-0.692, P< or =0.008). TMF E velocity did not correlate significantly with CVP or calculated SVR.

CONCLUSION

Phlebotomy during the dissection phase of liver transplantation decreased PVP, which was unaffected when phenylephrine infusion was used to restore systemic arterial pressure. This may contribute to a decrease in operative blood loss. CVP often increased in response to phenylephrine infusion and did not seem to reflect cardiac filling. The changes in TMF E velocity correlated well with the changes in CO, PAP, and PCWP during liver transplantation but not with the changes in CVP.