Spectral Doppler of the Hepatic Veins in Pulmonary Hypertension

Evaluation of Portal, Splenic, and Hepatic Vein Flows in Children Undergoing Congenital Heart Surgery

OBJECTIVE

Little is known about changes in portal, splenic, and hepatic vein flow patterns in children undergoing congenital heart surgery. This study aimed to determine the characteristics of portal, splenic, and hepatic vein flow patterns using ultrasonography in children undergoing cardiac surgery.

DESIGN

Single-center, prospective observational study.

SETTING

Tertiary children's hospital, operating room.

PARTICIPANTS

Children undergoing cardiac surgery.

MEASUREMENT AND MAIN RESULTS

The authors obtained ultrasound data from the heart, inferior vena cava, portal, splenic, and hepatic veins before and after surgeries. In the biventricular group, which included children with atrial and ventricular septal defects and pulmonary stenosis (n = 246), the portal pulsatility index decreased from 38.7% to 25.6% (p < 0.001) after surgery. The preoperative portal pulsatility index was significantly higher in patients with pulmonary hypertension (43.3% v 27.4%; p < 0.001). In the single-ventricle group (n = 77), maximum portal vein flow velocities of Fontan patients were significantly lower (13.5 cm/s) compared with that of patients with modified Blalock-Taussig shunt (19.7 cm/s; p = 0.035) or bidirectional cavopulmonary shunt (23.1 cm/s; p < 0.001). The cardiac index was inversely correlated with the portal pulsatility index in the bidirectional cavopulmonary shunt and Fontan circulation. (β = -5.693, r² = 0.473; p = 0.001) The portal pulsatility index was correlated with splenic venous pulsatility and hepatic venous atrial reverse flow velocity in biventricular and single-ventricle groups.

CONCLUSIONS

The characteristics of venous Doppler patterns in the portal, splenic, and hepatic veins differed according to congenital heart disease. Further studies are required to determine the association between splanchnic venous Doppler findings and clinical outcomes in this population.

Ultrasound Imaging of the Superior Vena Cava: A State-of-the-Art Review

Greater interest in imaging the superior vena cava (SVC) in recent years has arisen because of increased focus on disorders of the right heart; the growing use of transvenous access lines, dialysis catheters, and device leads; and the emergence of right ventricular mechanical circulatory support systems via the transcatheter approach. As a low-pressure venous conduit in the right upper mediastinum, the SVC is prone to compression by various pathologic processes, to invasion by malignancies originating in nearby structures, and to complications arising from intraluminal device leads and indwelling catheters. Computed tomography and magnetic resonance venography are the modalities of choice for structural imaging of the SVC. Ultrasound allows a reasonable, yet less detailed anatomic assessment of this venous conduit. Spectral and color Doppler imaging by ultrasound are the most valuable noninvasive tools for the interrogation of SVC blood flow, a marker of the filling pattern of the right heart. Analysis of the velocity, duration, and direction of the Doppler waveforms and their phasic response to respiration makes it possible to distinguish normal from abnormal flow patterns and offers diagnostic insights into disorders that affect right heart function. The aims of this review are to demonstrate the added value SVC imaging provides during transthoracic and transesophageal echocardiographic studies, to outline its usefulness for the detection and evaluation of structural abnormalities, and to detail the role of spectral Doppler imaging in aiding the diagnosis of various disorders that affect the right heart.

Diagnostic Performance of Pulsed Doppler Ultrasound of the Common Femoral Vein to Detect Elevated Right Atrial Pressure in Pulmonary Hypertension

Right atrial pressure (RAP) is an important prognostic criterion in pulmonary hypertension (PH). The main goals were to evaluate the following: (i) the accuracy of Doppler assessment of common femoral vein flow waveform to detect elevated RAP and (ii) the diagnostic accuracy of RAP assessed by echocardiography (eRAP). Fifty-seven patients, addressed for right heart catheterization, were included in a retrospective cross-sectional study during a 6-month period. Forty-five patients (78.9%) had PH confirmed by RHC. Elevated RAP was defined by RAP ≥ 10 mmHg. Femoral venous stasis index (FVSI) was highly correlated to RAP on both univariate (p < 0.001) and multivariate analysis (p = 0.003), and showed good diagnostic performances to detect elevated RAP (specificity: 92.3% [80.0-99.3], diagnosis accuracy: 90.4 [77.4-97.3], positive likelihood ratio: 12.5 [3.01-51.97]). Diagnosis accuracy of eRAP was only 51.2% (36.2-66.1). FVSI is independently correlated to RAP and a useful tool to predict elevated RAP in PH patients.

Venous Doppler to Assess Congestion: A Comprehensive Review of Current Evidence and Nomenclature

Organ congestion from venous hypertension is an important pathophysiological mechanism mediating organ injury in several clinical contexts including critical illness, congestive heart failure and end-stage chronic kidney disease. However, the practical evaluation of venous congestion is often challenging at the bedside because of the limitations of traditional methods. Point-of-care ultrasound (POCUS) enables the clinician to assess venous velocity profiles during the cardiac cycle using Doppler modalities. Venous Doppler profile abnormalities at multiple sites are detected when elevated venous pressure results in hemodynamic changes within the systemic venous circulation. The detection of these abnormal Doppler profiles may identify patients with clinically significant systemic venous congestion. These patients have been reported to be at increased risk of medical complications. Improving the evaluation of venous congestion may lead to individualized treatment and improved patient outcomes. In this review, we describe the physiologic principles necessary to understand venous Doppler assessment. We also propose a nomenclature for the description of venous Doppler profiles. Finally, we provide a narrative review of the current clinical evidence related to use of venous Doppler assessment in various clinical contexts.

Unexpected Vascular Ultrasound Findings Prompting Hemodynamic Management in an Infant in Respiratory Failure

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Central venous pulsatility can reflect pulmonary hypertension.

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Rapid assessment of cardiac findings helps expedite hemodynamic management.

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Procedural point-of-care ultrasound may suggest critical diagnostic findings.

Characterization of Doppler spectrum of hepatic veins in dogs with pulmonary hypertension

Pulmonary hypertension (PH) triggers hemodynamic changes within the right heart, which may affect hepatic venous flow. The aims of this study were three-fold: to investigate, prospectively, the reliability of the hepatic vein Doppler waveform to diagnose and characterize the magnitude of PH in dogs; to evaluate whether a correlation exists between hepatic venous flow waves and the structural and functional characteristics of the right ventricle (RV); and to determine whether age, gender, body weight, heart rate (HR), heart rhythm and systolic blood pressure affect the hepatic venous waveform pattern. A cross-sectional observational study was carried out in 43 dogs with varying degrees of PH and a control group of 15 healthy dogs. The velocities of the hepatic A, S, V and D spectral waves and the phasic pattern varied according to the severity of PH. Weak to moderate correlations were documented between hepatic vein waves and age, HR, and the structural and functional variables of the RV. A D Wave cut-off of 11.6 cm ∙ s-1 had a sensitivity of 100% and specificity of 35% for differentiation of dogs with severe PH from healthy dogs. Doppler assessment of hepatic venous flow was shown to be a reliable technique for screening dogs for PH.

Clinical utility of superior vena cava flow velocity waveform measured from the subcostal window for estimating right atrial pressure1

BACKGROUND

Superior vena cava (SVC) flow velocity waveform from the supraclavicular window reflects the right atrial pressure (RAP) status. Recent guidelines have stated that the subcostal window is an alternative view for recording SVC flow, but the validity of this approach remains unclear. This study aimed to determine the usefulness of SVC flow evaluation from the subcostal window for estimating RAP.

METHODS

Differences in SVC flow characteristics between opposite approaches were examined in 38 healthy adults. In 115 patients with cardiovascular diseases who underwent cardiac catheterization and echocardiography within 48 h, the ratio of peak systolic to diastolic forward SVC flows was measured (SVC-S/D), and the diagnostic ability of SVC-S/D for elevated RAP was tested. A validation cohort was conducted to confirm the diagnostic ability of SVC-S/D in 48 patients who underwent both cardiac catheterization and echocardiography within 24 h. In 59 patients of derivation and validation cohorts, the relationship between SVC flow and RAP was compared between the opposite windows.

RESULTS

Both systolic and diastolic SVC flow velocities were higher in the subcostal than in the supraclavicular approach, and effect of position change on the subcostal SVC-S/D was smaller than that on the supraclavicular SVC-S/D in healthy adults. Measurement of SVC-S/D from the subcostal window was feasible in 98 patients (85%). RAP was inversely correlated with SVC-S/D (r=-0.50, P<.001), and was an independent determinant of SVC-S/D after the adjustment for right ventricular systolic function (β=-0.48, P<.001). A cutoff value of 1.9 for SVC-S/D showed 85% sensitivity and 74% specificity in identifying elevated RAP. Additionally, SVC-S/D showed an incremental diagnostic value combined with inferior vena cava size and collapsibility (P=.006). When the cutoff value, SVC-S/D<1.9, was applied to the validation cohort, it showed an acceptable accuracy of 72%, and an incremental diagnostic value combined with inferior vena cava parameters (P=.033). SVC-S/D from the subcostal window correlated better with RAP than that from the supraclavicular window (P<.001, Meng's test).

CONCLUSIONS

Measurement of SVC flow velocity from the subcostal window was feasible, and SVC-S/D from the subcostal window could be an additive parameter for estimating RAP.

Transgastric Abdominal Ultrasonography in Anesthesia and Critical Care: Review and Proposed Approach

The use of transesophageal echocardiography (TEE) in the operating room and intensive care unit can provide invaluable information on cardiac as well as abdominal organ structures and function. This approach may be particularly useful when the transabdominal ultrasound examination is not possible during intraoperative procedures or for anatomical reasons. This review explores the role of transgastric abdominal ultrasonography (TGAUS) in perioperative medicine. We describe several reported applications using 10 views that can be used in the diagnosis of relevant abdominal conditions associated with organ dysfunction and hemodynamic instability in the operating room and the intensive care unit.

Doppler Interrogation of the Femoral Vein in the Critically Ill Patient: The Fastest Potential Acoustic Window to Diagnose Right Ventricular Dysfunction?

Objectives

To report the use of common femoral vein Doppler interrogation as a simple technique to diagnose right ventricular dysfunction.

Design

Case report.

Setting

Cardiac surgical ICU.

Patients

Postoperative cardiac surgical patients.

Interventions

Common femoral pulsed-wave and color Doppler examination associated with hepatic, portal, and renal venous Doppler measurement were obtained in both patients and before and after treatment in patient number 1. In addition, right ventricular pressure waveform examination was obtained in patient number 2.

Measurements and Main Results

The technique to obtain common femoral venous Doppler is described. Two cases of patients presenting with right ventricular dysfunction and fluid overload with portal and renal venous congestion in the perioperative period undergoing complex multivalvular cardiac surgery are presented. Hemodynamic waveform monitoring was performed alongside echocardiographic, hepatic, and renal venous flow Doppler assessment, and spectral Doppler profiles of the common femoral veins were examined. Those findings were useful in confirming our diagnosis and guiding our response to treatment. An algorithm was developed and tested on two additional hemodynamically unstable patients.

Conclusions

Doppler examination of the common femoral vein is a simple, fast, and noninvasive technique that could be useful to rule in the presence of right ventricular dysfunction with venous congestion and help guide the management of such patients.

Hepatic venous Doppler assessment can anticipate simplified pulmonary embolism severity index and right ventricle dysfunction in patients with acute pulmonary embolism

PURPOSE

Acute pulmonary embolism (APE) is a life-threating cardiothoracic thromboembolic emergency in which right ventricle dysfunction (RVD) is a major concern. In the present study, we examined the hepatic veins (HVs) blood flow with pulsed-wave spectral Doppler ultrasonography to determine its relationship with the simplified pulmonary embolism severity index (sPESI) and the patient's RVD status.

METHODS

We divided the 243 patients who met the inclusion criteria into two groups based on both their sPESI scores and their RVD status. Transthoracic echocardiography was performed to evaluate the RVD and the HVs within 1 hour after patient admission. The liver was evaluated using subcostal and intercostal echocardiographic windows in grayscale B-mode, and HVs were assessed using color and spectral Doppler assessment though the same echocardiographic windows.

RESULT

A cut-off value of the systolic reverse flow velocity-time integral (SrVTI) = 2.2 cm carried a sensitivity and specificity of 84.29% and 74.89%, respectively, for the prediction of sPESI ≥ 1. A SrVTI cut-off value of 2.1 cm yielded a sensitivity and specificity of 83.03% and 73.91%, respectively, for the prediction of RVD.

CONCLUSION

HV Doppler assessment could be a useful method for anticipating the sPESI and the presence of RVD in patients with APE. In addition, it may provide information regarding the hemodynamic impact of APE.

Hemodynamic changes of the middle hepatic vein in patients with pulmonary hypertension using echocardiography

The aim of this study was to analyze the changes of the middle hepatic vein (MHV) spectra in patients with pulmonary hypertension (PH) caused by congenital heart disease (CHD) and determine the proper parameters of MHV to predict PH. Eighty patients with CHD were included, whose pulmonary artery pressure was measured via right heart catheterization, and the MHV spectra were detected via echocardiography. The peak value of velocity (V) and velocity time integral (VTI) of the waves, including S wave, D wave and A wave, were measured at the end of inspiration. The values of the MHV parameters that were predictive of PH were evaluated and their cut-off points were determined. Compared with the control group, V of S wave (S), VTI of S wave (SVTI), V of D wave (D), VTI of D wave (DVTI) decreased and V of A wave (A), VTI of A wave (AVTI), A/S, AVTI/SVTI, A/(S+D), AVTI/ (SVTI+DVTI) increased in the PH group. These differences were statistically significant (P<0.05). A correlation analysis determined that the ratios of A/S, A/(S+D), AVTI/(SVTI+DVTI) were positively correlated with pulmonary artery mean pressure (r=0.529,0.575,0.438,P<0.001). An ROC curve analysis determined that the diagnostic effect of A/(S+D) was superior to the other two parameters. On the ROC curve, when the ratio of A/(S+D) was 0.30, the sensitivity was 85.37% and specificity was 75.00% for predicting PH. The spectral parameters of MHV, including the ratios of A/S, A/(S+D) and AVTI/(SVTI+DVTI), increased with increasing pulmonary pressure in CHD patients. When the ratio of A/(S+D) was 0.30 in MHV spectra, it had sufficient sensitivity and specificity for diagnosing PH, and this method could be used as a new non-invasive complementary echocardiographic parameter for predicting PH.

Respiratory hemodynamics in the hepatic veins-normal pattern

Doppler interrogation of blood flow in the hepatic veins (HVs) is a part of any comprehensive echocardiographic examination. Data derived from the HV Doppler provide a useful tool for the assessment of right heart function. Beyond its dependence on the cardiac cycle, right heart hemodynamics, and compliance of the liver parenchyma, blood flow in the HVs is influenced by the respiratory cycle. Systematic analysis of the behavior of the HV Doppler during respiration allows one to recognize normal and abnormal flow-patterns and distinguish among various disease states that involve the right heart. In this manuscript we discuss the effect of respiration on the HV Doppler in individuals with normal right heart function.