The pulsatile portal vein in cases of congestive heart failure: correlation of duplex Doppler findings with right atrial pressures

Monitoring the venous circulation: novel techniques and applications

PURPOSE OF REVIEW

Venous pressure is an often-unrecognized cause of patient morbidity. However, bedside assessment of PV is challenging. We review the clinical significance of venous pressure measurement, existing techniques, and introduce the Venous Excess Ultrasound (VExUS) Score as a novel approach using doppler ultrasound to assess venous pressure.

RECENT FINDINGS

Studies show clear associations between elevated venous pressure and adverse outcomes in critically ill patients. Current venous pressure measurement techniques include physical examination, right heart catheterization (RHC), two-dimensional ultrasound, and a variety of labor-intensive research-focused physiological maneuvers. Each of these techniques have specific shortcomings, limiting their clinical utility. To address these gaps, Beaubien-Souligny et al. introduced the VExUS Score, a novel doppler ultrasound-based method that integrates IVC diameter with doppler measurements of the hepatic, portal, and renal veins to generate a venous congestion assesment. Studies show strong correlations between VExUS score and RHC measurements, and well as an association between VExUS score and improvement in cardiorenal acute kidney injury, diuretic response, and fluid status shifts. However, studies in noncardiac populations have been small, heterogenous, and inconclusive.

SUMMARY

Early studies evaluating the use of doppler ultrasound to assess venous congestion show promise, but further research is needed in diverse patient populations and clinical settings.

Prospective Evaluation of Venous Excess Ultrasound for Estimation of Venous Congestion

BACKGROUND

Venous excess ultrasound (VExUS) is a novel ultrasound technique previously reported as a noninvasive measure of venous congestion and predictor of cardiorenal acute kidney injury.

RESEARCH QUESTION

Are there associations between VExUS grade and cardiac pressures measured by right heart catheterization (RHC) and cardiac biomarkers and clinical outcomes in patients undergoing RHC?

STUDY DESIGN AND METHODS

We conducted a prospective cohort study at the Denver Health Medical Center from December 20, 2022, to March 25, 2023. All patients undergoing RHC underwent a blinded VExUS assessment prior to their procedure. Multivariable regressions were conducted to assess relationships between VExUS grade and cardiac pressures, biomarkers, and changes in weight among patients with heart failure, a proxy for diuretic success. Receiver operating characteristic curve and area under the curve (AUC) were derived for VExUS, inferior vena cava (IVC) diameter, and IVC collapsibility index (ICI) to predict right atrial pressure (RAP) > 10 and < 7 mm Hg.

RESULTS

Among 81 patients, 45 of whom were inpatients, after adjusting for age, sex, and Charlson Comorbidity Index, there were significant relationships between VexUS grade of 2 (β = 4.8; 95% CI, 2.6-7.1; P < .01) and 3 (β = 11; 95% CI, 8.9-14; P < .01) and RAP, VExUS grade of 2 (β = 6.8; 95% CI, 0.16-13; P = .045) and 3 (β = 15; 95% CI, 7.3-22; P < .01) and mean pulmonary artery pressure, and VExUS grade of 2 (β = 7.0; 95% CI, 3.9-10; P < .01) and 3 (β = 13; 95% CI, 9.5-17; P < .01) and pulmonary capillary wedge pressure. AUC values for VExUS, IVC diameter, and ICI as predictors of RAP > 10 mm Hg were 0.9 (95% CI, 0.83-0.97), 0.77 (95% CI, 0.68-0.88), and 0.65 (95% CI, 0.52-0.78), respectively. AUC values for VExUS, IVC diameter, and ICI as predictors of RAP < 7 mm Hg were 0.79 (95% CI, 0.70-0.87), 0.74 (95% CI, 0.64-0.84), and 0.62 (95% CI, 0.49-0.76), respectively. In a subset of 23 patients with heart failure undergoing diuresis, there was a significant association between VExUS grade 3 and change in weight between time of RHC and discharge (P = .025).

INTERPRETATION

Although more research is required, VExUS has the potential to increase diagnostic and therapeutic capabilities of physicians at the bedside and increase our understanding of the underappreciated problem of venous congestion.

Prognostic value of Doppler waveform analysis of common femoral vein in septic patients: a prospective cohort study

OBJECTIVES

To assess whether there is an association between abnormal common femoral vein (CFV) Doppler waveform and intensive care unit (ICU) mortality in patients with sepsis.

METHODS

Patients admitted to the ICU with sepsis were included. Pulsed-wave Doppler was performed by examining the CFV in the short axis without angle correction and in the long axis with angle correction. An abnormal CFV Doppler waveform was determined by a retrograde velocity peak (RVP) > 10 cm/s in the long axis or RVP > 50% of the antegrade velocity peak in the short axis. TAPSE < 17 mm was defined as right ventricular (RV) dysfunction. The primary outcome was ICU mortality.

RESULTS

One hundred and ten patients were included. There was no association between abnormal CFV Doppler waveforms in the long (p = 0.709) and short axes (p = 0.171) and ICU mortality. TAPSE measurements were performed in 16 patients. RV dysfunction was identified in 8 (50.0%) patients. There was no association between the diagnosis of RV dysfunction based on TAPSE measurement and the identification of abnormal CFV Doppler waveforms in the long axis (p = 1.000) and in the short axis (p = 1.000).

CONCLUSION

Abnormal CFV Doppler waveforms were not associated with ICU mortality in patients with sepsis. Furthermore, in the exploratory analysis, these alterations were not useful in identifying RV dysfunction in these patients.

Venous Excess Doppler Ultrasound for the Nephrologist: Pearls and Pitfalls

The role of venous congestion in abnormal kidney function is being increasingly recognized. It is well known that unresolved congestion is associated with adverse kidney and overall outcomes in patients with heart failure. Similarly, any condition that leads to elevated central venous pressure, such as pulmonary hypertension, can result in impaired kidney perfusion by increasing its afterload. Point-of-care ultrasonography (POCUS) enables the clinician to objectively assess hemodynamics at the bedside and, thereby, guide patient management. Lung POCUS has received widespread attention in the recent past because of the relative ease of the technique, but it reflects only left heart pressures and not venous congestion. Although inferior vena cava POCUS is used to estimate right atrial pressure, its isolated use cannot demonstrate organ congestion. Moreover, it is associated with several technical and conceptual limitations. Recently, venous excess Doppler ultrasound has emerged as a tool to assess venous congestion at the organ level in real time. Severe flow abnormalities in hepatic, portal, and kidney parenchymal veins have shown to predict the risk of congestive kidney injury. In addition, it helps to objectively monitor the efficacy of decongestive therapy. In this review, we provide a brief overview of various components of venous excess Doppler ultrasound and share our perspective on incorporating this novel tool in nephrology practice.

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.

Lymphocytopenia During Hospitalization for Acute Heart Failure and Its Relationship With Portal Congestion and Right Ventricular Function

BACKGROUND

Lymphocytopenia is associated with mortality in acute heart failure (AHF), and portal congestion has been suggested to play a role in leukocyte distribution. The associations between lymphocytopenia and ultrasound surrogates for portal congestion have never been studied. We aimed to characterize the determinants of lymphocytopenia, explore the associations between lymphocytopenia and portal congestion, and explore the relationships between lymphocytopenia and outcomes in AHF.

METHODS AND RESULTS

Patients were compared according to tertiles of lymphocyte count (very low, <0.87 × 10⁹/L; low, 0.87-1.2 × 10⁹/L; or normal, >1.2 × 10⁹/L). One hundred three patients with AHF were prospectively assessed at baseline and discharge. At baseline, 69% of patients had a lymphocyte count below the normal range. Patients with baseline very low lymphocyte count were older, had more advanced disease and higher portal vein pulsatility index when compared with those in the higher tertiles. Very low lymphocyte count at baseline was associated with age (odds ratio (OR) 1.098), portal vein pulsatility index (OR, 1.026), and tricuspid annular plane systolic excursion (OR, 0.865, all P < .05). The portal vein pulsatility index was the most powerful determinant of lymphocytopenia at discharge (OR 1.033, P < .05). In a Cox model, lymphocytopenia at discharge was associated with mortality (hazard ratio 4.796, P < .05).

CONCLUSIONS

In AHF, lymphocytopenia is associated with ultrasound surrogates for portal congestion and right ventricular dysfunction. Whether these associations depict a potent pathophysiologic pathway or whether they only reflect a more advanced disease remains uncertain.

Assessing Splanchnic Compartment Using Portal Venous Doppler and Impact of Adding It to the EVEREST Score for Risk Assessment in Heart Failure

Background

The Efficacy of Vasopressin Antagonism in Heart Failure: Outcome Study with Tolvaptan (EVEREST) score has proven useful for risk prediction in acute decompensated heart failure (ADHF). However, this score does not include the characterization of the splanchnic compartment, which has been involved in worsening heart failure. Refining this score by integrating an assessment of the splanchnic compartment would allow for a better risk assessment. Therefore, we aimed to characterize the patterns of portal vein pulsatility (PVP), an ultrasound metric used for the assessment of splanchnic compartment and their determinants in patients with ADHF, to explore the relationships between abnormal patterns of PVP and outcomes, and to evaluate the added value of PVP to the EVEREST score for risk assessment in ADHF.

Methods

Portal vein flow was assessed prospectively on admission and at discharge in 95 patients with ADHF using pulsed-wave Doppler. Abnormal PVP was defined for values ≥ 50%. Cox proportional hazards models were used for the assessment of the relationship between PVP and outcomes.

Results

Overall, 64% of patients on admission and 24% at discharge had abnormal PVP. PVP on admission was inversely correlated with right ventricular function (tricuspid annular plane systolic excursion, ρ = −0.434) and pulmonary pressure (ρ = 0.346), P < 0.05. Although PVP was associated with all-cause mortality (hazard ratio, 1.028, P < 0.001), the addition of this metric to the EVEREST score had little effect on its C-index (0.813 vs 0.818) for risk assessment.

Conclusions

Abnormal PVP is frequent and associated with right ventricular dysfunction in ADHF. Although abnormal PVP identifies higher-risk patients, this metric does not improve the performance of the EVEREST score for risk assessment.

Hepatic and portal vein Dopplers in the clinical management of patients with right-sided heart failure: two case reports

Background

Patients with right heart failure pose significant volume management challenges for hemodynamic optimization. We present two cases in which point of care ultrasound (POCUS) of the hepatic and portal veins contributed to the venous hypertension assessment and decongestive strategy for patients with right-sided heart failure.

Case presentation

Patient A was 91 years old with known pulmonary hypertension and right ventricular systolic dysfunction who presented in septic shock requiring vasopressor support. Hepatic and portal vein Dopplers were consistent with right heart failure and significant venous congestion, therefore, diuresis was initiated which resulted in portal flow normalization, renal recovery, and cessation of vasopressor support. Patient B was 82 years old with severe idiopathic pulmonary fibrosis on home oxygen who presented in decompensated right heart failure. Despite aggressive diuresis, a negative fluid balance was not achieved. The patient continued to deteriorate and prior to their death portal vein, Doppler showed significant flow reversal.

Conclusion

Hepatic and portal vein Doppler ultrasounds are venous hypertension assessment tools that can be readily used at the bedside by clinicians trained in POCUS that may contribute holistically to the hemodynamic profiling for patients with right heart failure and direct therapeutic interventions.

Experimental evaluation of portal venous pulsatile flow synchronized with heartbeat intervals: effects of vascular clamping on portal hemodynamics

PURPOSE

We previously showed that blood flow in the portal vein was pulsatile and influenced by both the inferior vena cava and the arterial system in a complex manner (Nihei et al., 38:141-149, 2011). The objective of the present study is to identify determinants of blood flow and to clarify the source of pulsatile flow in the portal vein.

METHODS

Three-breed terminal crossbreed mini-pigs underwent general anesthesia. Pressure and flow in the portal vein, inferior vena cava, hepatic artery, and mesenteric artery were measured simultaneously. Vascular occluders were placed in the inferior vena cava, hepatic artery, and mesenteric artery to examine the effects of clamping on portal venous flow.

RESULTS

Clamping of the mesenteric artery altered pressure and flow waves in the portal vein to waveforms similar to those in the inferior vena cava. Waves resembling those of the inferior vena cava superimposed on portal venous flow appeared later than waves of the inferior vena cava. Clamping of the inferior vena cava promptly altered portal venous pressure and flow. Because clamping of the inferior vena cava led to a sharp rise in portal venous pressure, detailed evaluations were not feasible. Clamping of the hepatic artery had no effect on flow-wave pulsation in the portal vein.

CONCLUSIONS

In the hepatic circulation, flow-wave pulsation in the portal vein is influenced by flow in the inferior vena cava via the sinusoids and by flow in the mesenteric artery via the capillary vessels of the intestine.

Hepatofugal portal venous flow on Doppler sonography after liver transplantation. Analysis of presumed causes based on radiologic and pathologic features

OBJECTIVES

The purpose of this study was to categorize hepatofugal portal venous flow on Doppler sonography after liver transplantation and to investigate its clinical importance and presumed causes based on radiologic and pathologic findings.

METHODS

This retrospective study was approved by our Institutional Review Board, and the requirement for informed consent was waived. Examination of our database over 4 years revealed 30 patients in whom Doppler sonography showed hepatofugal portal venous flow during follow-up periods. We investigated its occurrence and clinical features, including radiologic and pathologic findings, and classified the possible causes into 5 types: A, systemic problems; B, gross vascular abnormalities correctable by intervention; C, specific cardiac problems; D, microscopic abnormalities of the graft; and E, miscellaneous. We classified the patterns of hepatofugal portal venous flow into continuous hepatofugal or hepatofugal-dominant to-and-fro flow and hepatopetal-dominant to-and-fro flow, and we investigated the relationship of the presumed causes and flow patterns with the clinical course.

RESULTS

The incidence of hepatofugal portal venous flow was 2.38%. The overall mortality rate was 26.67% (95% confidence interval, 11.1%-42.9%): all patients (n = 5) in group A, 1 in group C, and 2 in group D, died. Possible cause type B and a mainly hepatopetal flow pattern were good prognostic factors (P = .031 and .018, respectively).

CONCLUSIONS

Hepatofugal portal venous flow reflects diverse pathologic conditions after liver transplantation, and its clinical importance also differs depending on the cause.

Experimental evaluation of portal venous pulsatile flow synchronized with heartbeat intervals

PURPOSE

The aim of this study was to analyze pulsatile flow in the portal vein, to clarify the origin of pulsatile flow, and to acquire new knowledge about the hepatic circulation.

METHODS

Mini-pigs underwent general anesthesia. Pressure and flow in the portal vein, inferior vena cava, hepatic artery, and mesenteric artery were measured simultaneously. We (1) studied the relationship between changes in pressure and changes in flow and (2) measured heartbeat intervals and the onset times of pressure and flow waves.

RESULTS

In the inferior vena cava, pressure and flow showed mirror-image changes. In the hepatic artery and the mesenteric artery, pressure and flow increased simultaneously. In the inferior vena cava, the longer the heartbeat interval, the more delayed were the onset times of pressure and flow waves. The onset time of pressure and flow waves in the hepatic artery and the mesenteric artery was only minimally affected by changes in heartbeat interval. The relationship between pressure and flow in the portal vein was closer to that in the hepatic artery and the mesenteric artery. However, the onset times of pressure and flow waves in the portal vein showed two different patterns: some showed a pattern similar to that of the inferior vena cava, whereas others showed a pattern similar to that of the hepatic artery and the mesenteric artery.

CONCLUSIONS

Blood flow in the portal vein is pulsatile and influenced by both the inferior vena cava and the arterial system in a complex manner.

How far can we go with positive end-expiratory pressure (PEEP) in liver transplant patients?

STUDY OBJECTIVE

To assess the effect of positive end-expiratory pressure (PEEP) up to 15 cm H(2)O on blood flow throughput of the liver and its effects on systemic hemodynamics in patients following liver transplantation.

DESIGN

Prospective, interventional study.

SETTING

Intensive care unit (ICU) of a university hospital.

PATIENTS

74 consecutive liver transplant recipients with a regular allocated cadaveric graft.

INTERVENTION

The lungs of all study patients were postoperatively mechanically ventilated with biphasic positive airway pressure. Three different PEEP levels (5, 10, and 15 cm H(2)O) were randomly set within 4 hours of admission to the ICU. Systemic hemodynamic parameters were recorded using a pulmonary artery catheter and flow velocities were measured of the hepatic artery, portal vein, and right hepatic vein using a Doppler.

MEASUREMENTS AND MAIN RESULTS

PEEP of 15 cm H(2)O induced a significant increase in central venous pressure and pulmonary capillary wedge pressure versus PEEP 5 cm H(2)O. Flow velocities of the right hepatic vein, portal vein, and hepatic artery were not influenced by PEEP. There also was no impact of increased PEEP on mean arterial pressure or cardiac index.

CONCLUSION

PEEP up to 15 cm H(2)O does not impair liver outflow or systemic hemodynamics in liver transplant patients.

Is positive end-expiratory pressure suitable for liver recipients with a rescue organ offer?

PURPOSE

Rescue organ offers may help to overcome the organ shortage. However, because of initial poor liver function, the recipient may develop a severe lung injury with the requirement for higher positive end-expiratory pressure (PEEP) levels to achieve adequate oxygenation. Positive end-expiratory pressure has been associated with perfusion impairment in the hepatosplanchnic area. We assessed the effects of increased PEEP levels on systemic hemodynamic and liver perfusion in liver transplantation (LT) patients with a rescue organ.

METHODS

Twenty-four LT recipients of a rescue organ offer were enrolled. All patients were postoperatively mechanically ventilated with biphasic positive airway pressure, and 3 different PEEP levels (0, 5, 10 mbar) were randomly set within 4 hours after admission at the intensive care unit. Systemic hemodynamic parameters were recorded using a pulmonary artery catheter; and flow velocities of the hepatic artery, portal vein, and right hepatic vein were measured using Doppler.

RESULTS

Positive end-expiratory pressure of 10 mbar did not impair the systemic hemodynamic. Flow velocities in the right hepatic vein, the portal vein, and the hepatic artery were not influenced by PEEP.

CONCLUSION

Our study demonstrates that PEEP up to 10 mbar did not impair the liver outflow in recipients with a rescue organ offer.

Doppler sonography of portal hypertension

Doppler sonography is frequently obtained in patients with chronic liver disease, patients with suspected portal hypertension, and patients with known portal hypertension. In this clinical setting, it is important to understand both the normal hemodynamics of the liver and the morphological and hemodynamic changes that occur with portal hypertension. Among the many findings of portal hypertension are enlargement of the portal vein, decreased portal vein velocity, increased congestion index, development of portosystemic collaterals, and reversal of portal vein flow. The most important portal systemic collaterals to focus on with Doppler are the coronary vein and the umbilical vein. Using all of these clues, it is possible to diagnose portal hypertension with a high degree of sensitivity and specificity in most patients.

Does PEEP impair the hepatic outflow in patients following liver transplantation?

OBJECTIVE

Evaluation of the impact of end-expiratory pressure (PEEP) ventilation on venous liver outflow, portal vein, and hepatic artery flows as well as systemic hemodynamics in patients following liver transplantation (LT).

DESIGN

Prospective, interventional patient study.

SETTING

University hospital intensive care unit.

PATIENTS

65 consecutive patients after LT.

INTERVENTIONS

All patients were intubated and mechanically ventilated with biphasic positive airway pressure (BIPAP). The effects of three levels of PEEP (0, 5, and 10 mbar) applied at random order on hepatic inflow and outflow were studied in the immediate postoperative period.

MEASUREMENT AND RESULTS

Central venous-, arterial pressure, and cardiac index was recorded from every patient at three different PEEP levels (0, 5, and 10 mbar). Simultaneously, flow velocities in the hepatic-, portal vein, and hepatic artery were determined by Doppler ultrasound. PEEP of 10 mbar significantly increased central venous pressure in comparison with zero PEEP. Mean arterial pressure and cardiac index was not influenced. Hepatic inflow and outflow of the transplanted livers were not impaired by any of the used PEEP levels.

CONCLUSIONS

BIPAP ventilation with PEEP levels up to 10 mbar does not affect systemic hemodynamics. Furthermore, neither venous outflow nor portal venous or hepatic artery inflow of the liver are impaired at PEEP levels up to 10 mbar immediately following liver transplantation. Although these results suggest that PEEP ventilation up to 10 mbar does not affect liver hemodynamics, further studies are needed to determine whether these findings could be confirmed for a longer ventilation period with PEEP.

Value of Doppler sonography in assessing the progression of chronic viral hepatitis and in the diagnosis and grading of cirrhosis

OBJECTIVE

The purpose of this study was to evaluate the value of Doppler sonography in assessing the progression of chronic viral hepatitis and in the diagnosis and grading of cirrhosis.

METHODS

Abdominal sonographic and liver Doppler studies were performed in 3 groups: 36 patients with chronic viral hepatitis, 63 patients with cirrhosis, and 30 control subjects with no evidence of liver disease. A series of Doppler indices of hepatic vascularity, including portal vein velocity, portal vein pulsatility score, flow volume of the portal vein, resistive and pulsatility indices of the hepatic artery, modified hepatic index, hepatic vascular index, waveform of the hepatic vein, and focal acceleration of flow, were measured and correlated with liver and spleen size, portal and splenic vein diameter, and presence of ascites and collateral vessels. These indices were compared across the 3 study groups and within the patient groups with respect to presence of inflammation, fibrosis, and steatosis, as determined by histologic evaluation.

RESULTS

The most useful indices were portal vein velocity, the modified hepatic index, and nontriphasic flow in the hepatic vein, which were helpful in distinguishing patients from control subjects. Hepatic vascular and modified hepatic indices were useful for differential diagnosis of cirrhosis and chronic viral hepatitis. However, all measurements were limited in their ability to determine the severity of chronic hepatitis.

CONCLUSIONS

Doppler sonography is sensitive to hemodynamic alterations resulting from inflammation and fibrosis, and if sonography is the study of choice to follow the progression of hepatitis, it will not be adequate without Doppler imaging. Doppler sonography has high diagnostic accuracy in cirrhosis despite some false-positive conditions. However, it has a limited role in clinical grading.

Hepatic response to right ventricular pressure overload

BACKGROUND & AIMS

Modifying the afferent blood supply to the liver does not change the zonal expression pattern of hepatic enzymes in the rat.

METHODS

We used pulmonary trunk banding (PTB) to study the effect of an efferent hindrance of blood flow on hepatic architecture and zonation of gene expression.

RESULTS

Most PTB rats developed right ventricular hypertrophy and congestive heart failure. The hepatic response to PTB developed concomitantly with the decline in heart function. Enzyme expression in the periportal region was not affected, but the pericentral rim of hepatocytes expressing glutamine synthetase, ornithine aminotransferase, and NADPH cytochrome P-450 reductase (CYPred) first declined in diameter, then became discontinuous, and finally disappeared. Meanwhile, ornithine aminotransferase and especially CYPred, became re-expressed in the periportal zone. These changes occurred without appreciable cell death or fibrotic changes; the expression of fibronectin and alpha-smooth muscle actin increased perisinusoidally, but that of collagen did not. Electron microscopic analysis revealed normal fenestration of the sinusoidal endothelial cells without detectable deposition of basement membrane material, but both the width of the space of Disse and the length and number of hepatic microvilli were significantly reduced, implying a decreased flow of fluid in the space of Disse.

CONCLUSIONS

The reprogramming of gene expression in livers with a postsinusoidal hindrance of blood flow results from declining access of the hepatocytes to intrasinusoidal signal-transduction molecules and suggest that the impaired biotransformation that accompanies right ventricular failure is caused by a central-to-portal shift in expression of the corresponding enzymes.

Color Doppler sonographic signs of respiration-dependent hepatofugal portal flow

PURPOSE

The role of respiration in modulating blood flow in the portal vein is unclear. The aim of this study was to investigate the phenomenon of respiration-dependent periodic hepatofugal portal venous blood flow as detected on color Doppler sonography.

METHODS

Within 1 year, we identified 13 patients with respiration-dependent reversal of blood flow in the portal vein that was diagnosed on color Doppler sonography. This phenomenon was investigated by color Doppler sonographic examination of the portal venous flow during both mid-inspiration breath-holding and a respiratory cycle including deep inspiration; evaluation of hepatic vein Doppler waveforms as normal (triphasic) or decreased (flattened); and echocardiographic examination to determine the presence or absence of tricuspid regurgitation.

RESULTS

The patients' median age was 53 years (range, 26-87 years). Seven of the 13 patients had heart disease (tricuspid regurgitation) with or without liver disease, 3 had liver disease without heart disease, and 3 had other diseases with no evidence of heart or liver disease. On Doppler sonography, 10 of the 13 patients had increased portal venous pulsatility (7 of the 10 had tricuspid regurgitation; the other 3 did not); the remaining 3 patients had neither increased pulsatility nor tricuspid regurgitation. Sonographic follow-up within 4 weeks in 4 of the 13 patients revealed loss of the respiration-dependent hepatofugal portal flow.

CONCLUSIONS

Respiration-dependent hepatofugal portal flow is a rare finding associated with periodic portal hypertension in patients with right heart insufficiency and liver disease. Its clinical significance is unclear. Among our patients, its occurrence was predominantly associated with an increased venous pulsatility index due to tricuspid regurgitation or venous outflow obstruction. Further study is needed to investigate whether periodic respiration-dependent hepatofugal portal flow is predictive of the occurrence of continuous flow reversal.

Pictorial review: Colour Doppler ultrasound flow patterns in the portal venous system

Doppler ultrasound is a well established method for assessment of the portal venous system to detect the direction of portal blood flow. It is helpful for non-invasive diagnosis of intra-abdominal portosystemic shunts, especially in patients with cirrhosis. Less attention has been paid to other influences on portal venous flow, e.g. tricuspid regurgitation, increased hepatic out-flow resistance, respiratory cycle. The aim of this pictorial review is to describe the spectrum of physiological and pathological Doppler ultrasound flow patterns in the portal venous system.

Portal vein pulsatility and spectral width changes in patients with portal hypertension: relation to the severity of liver disease

Using Doppler ultrasound in patients with chronic liver disease (CLD) and portal hypertension, portal vein pulsatility pattern and spectral width changes were assessed and evaluated in relation to the severity of liver disease as determined according to the Child-Pugh score. The pulsatility index (PI) was significantly lower in CLD patients (mean+/-SD: 0.23+/-0.08) compared with healthy subjects (0.39+/-0.1) (p<0.001) and lower in Child-Pugh class C compared with Child-Pugh class A patients (0.21+/-0.07 vs 0.25+/-0.08, respectively) (p<0.05). The spectral width index was significantly higher in CLD patients vs healthy subjects (0.91+/-0.16 vs 0.60+/-0.12, respectively) (p<0.001). The difference was also noted in the early stage (Child-Pugh A patients) when compared with healthy subjects (0.88+/-0.17). In conclusion, portal vein pulsatility and spectral width indices can reflect the early haemodynamic changes in CLD patients. These changes become more pronounced with the progression of liver disease.

Correlation of right atrial pressure and blood flow velocities in the common femoral vein obtained by duplex Doppler sonography

PURPOSE

The purpose of this study was to correlate the right atrial pressure with the blood flow velocity and pulsatility index (PI) values obtained with duplex Doppler sonography of the common femoral vein.

METHODS

Thirty consecutive patients with suspected right-sided heart failure who had right atrial pressure measurements for correlation were included in the study. The common femoral veins were examined with duplex Doppler sonography. Irrespective of the presence or absence of clinical right-sided heart failure, patients were divided into 2 groups on the basis of their right atrial pressures. The mean flow velocities and PIs in the common femoral veins of the 2 groups were compared.

RESULTS

In patients with elevated right atrial pressure (> or = 8 mm Hg), the mean minimum flow velocity + standard deviation (-0.15 +/- 0.11 m/second) in the common femoral vein was significantly lower than that in patients with normal right atrial pressure (< 8 mm Hg) (0.01 +/- 0.10 m/second) (p < 0.001). There was no significant difference in the mean maximum flow velocities in the common femoral vein between the patients with elevated right atrial pressure (0.25 +/- 0.08 m/second) and the patients with normal right atrial pressure (0.21 +/- 0.09 m/second). The mean PI in patients with elevated right atrial pressure (7.75 +/- 3.19) was significantly higher than the mean PI in patients with normal right atrial pressure (1.55 +/- 1.30; p < 0.001). There was a weak negative correlation between the minimum flow velocity and the pressure in the right atrium in patients with elevated right atrial pressure (p = 0.05; r = -0.4760). The amplitude of retrograde waves seen in patients with normal right atrial pressure was significantly smaller than in patients with elevated right atrial pressure (p < 0.05).

CONCLUSIONS

The association of a decreased minimum velocity, especially a negative value, and an increase in PI in the common femoral vein may indicate an elevated right atrial pressure. Sonographic assessment of retrograde flow velocity in the common femoral vein may be useful in monitoring the response to medical treatment to decrease atrial pressure.

Doppler sonographic diagnosis of severe portal vein pulsatility in constrictive pericarditis: flow normalization after pericardiectomy

This case report describes the noninvasive assessment of hepatic and portal vein hemodynamics in a patient with constrictive pericarditis before and after pericardiectomy. Doppler sonography of the hepatic veins demonstrated a typical W-shaped pattern with pronounced late diastolic flow reversal that disappeared after surgery. Preoperatively, we observed severe pulsatility of the portal vein with flow reversal in systole; after pericardiectomy, portal venous flow was normal. We concluded that the high right atrial pressure in this patient might have led to increased hepatic venous outflow resistance, with subsequent trans-sinusoidal shunting between the hepatic artery and portal vein causing severe portal vein pulsatility. After pericardiectomy and a decrease in right atrial pressure, portal vein flow normalized.

Doppler ultrasound evaluation of advanced portal vein pulsatility in patients with normal echocardiograms

The hypothesis tested that mechanisms other than retrograde transsinusoidal fluid wave transfer reported in patients with right heart failure are responsible for the ultrasonographic sign of advanced portal vein pulsatility (APP). Within a time-period of 3 years we have seen 13 patients with APP, defined as temporary portal flow reversal in the face of a normal echocardiogram. Nine of these patients had biopsy-proven liver cirrhosis and four with liver disease were without cirrhosis or cardiac pathology. A randomly selected control group of 18 healthy subjects was studied. Doppler ultrasound evaluation of the hepatic veins as well as the intra and extrahepatic portal vein territories was performed in both groups. Hepatopetal portal flow with APP reversed to hepatofugal flow in follow up studies in two patients. In another two hepatopetal flow with APP in the main portal vein and hepatofugal flow in the intrahepatic portal radicles was recorded during the same examination. The remaining group displayed APP in the intra and extrahepatic portal vein territories. None of the normal subjects presented with APP. Hepatic venous outflow obstruction associated with excessive arterioportal shunting is likely to account for APP of all of our patients. Based on a causal link between angiographic 'to-and-fro' flow pattern and the sonographic APP sign in patients with sinusoidal outflow obstruction we suggest, that APP expresses a short, transitional period of portal hypertension just before the occurence of flow reversal.

Portal vein pulsatility ratio provides a measure of right heart function in chronic heart failure

Portal vein flow was recorded by color Doppler sonography in 31 patients with chronic heart failure and 18 control subjects. Compared with patients showing a forward flow (Group A), those with reversed portal vein flow (Group B) had higher prevalence of tricuspid regurgitation (75% vs. 43%), hepatic congestion (100% vs. 30%) and ascites (50% vs. 18%), and showed higher right atrial pressure (25.3 +/- 3.01 mmHg vs. 11.8 +/- 5.75 mmHg, p < 0.01). In controls, portal vein pulsatility ratio was 0.66 +/- 0.08, in Group A it was 0.46 +/- 0.28 (p < 0.01), in Group B -0.60 +/- 0.19 (p < 0.01). Portal vein pulsatility ratio negatively correlated with right atrial pressure (r = -0.87; p < 0.01). In Group A, hepatic congestion, ascites and tricuspid regurgitation were associated with a higher portal vein pulsatility. This study indicates that portal vein pulsatility ratio reflects the level of impairment of the right heart.

Portal vein pulsatility ratio and heart failure

PURPOSE

Heart diseases can alter liver volume, morphology, and circulation. The Doppler pulsatility of the portal vein and its pulsatility ratio (PR) have been reported as being closely associated with the right atrial pressure and with the New York Heart Association (NYHA) class. We examined the relationships between measurements of liver and spleen dimensions and blood flow in portal and hepatic veins, assessed noninvasively by Doppler sonography, and compared them with echocardiographic data.

METHODS

The study group comprised 87 inpatients with heart failure. The mean age was 64+/-12 years. Patients underwent duplex Doppler sonography of the heart and portal and hepatic veins.

RESULTS

Patients with more severe left ventricular failure (NYHA class III-IV) showed more dilatation of the left ventricle and atrium, reduced systolic function, and reduced portal vein mean velocity compared with patients with milder heart failure (NYHA class I-II); in addition, the hepatic vein diameter was increased and portal vein PR was reduced. Considering all patients, significant positive correlations were found between portal vein PR and left ventricular shortening fraction (r= 0.34, p < 0.01) and ejection fraction (r= 0.38, p < 0.001). Significant negative correlations were found between PR and hepatic vein diameter (r= -0.44, p < 0.001), right ventricle diameter (r = -0.38, p < 0.001), left ventricular end-diastolic volume (r = -0.31, p < 0.01), and left atrium diameter (r = -0.33, p < 0.01). Patients with hepatic vein dilatation had increased left ventricular volumes, reduced systolic function indices, and portal vein alterations (increased diameter, reduced mean velocity, and reduced PR). In patients with an ejection fraction of no more than 50%, only PR was significantly reduced, while other sonographic liver measurements were not significantly different.

CONCLUSIONS

The effects of cardiac failure on portal blood flow, which declines progressively with worsening cardiac function, is shown better by the pulsatility pattern of the portal vein than by morphologic caval and hepatic vein measurements. PR can be used as a reliable adjunctive sign of heart failure.

Sonographic diagnosis of hepatic vascular disorders

Perhaps the most valuable application of duplex sonography in the abdomen is in the diagnosis of vascular disorders of the liver. Duplex sonography provides an accurate assessment of the portal and hepatic venous systems that is both noninvasive and convenient, because the examination can be conducted at the bedside. In this article, the normal features of portal and hepatic venous flow are considered as well as the sonographic manifestations of pathological conditions, including: (1) portal hypertension; (2) portosystemic collaterals; (3) portal vein thrombosis; and (4) hepatic vein thrombosis (Budd-Chiari syndrome).

Portal vein pulsatility in normal and cirrhotic adults without cardiac disease

The literature indicates that Doppler demonstration of pulsatile flow in the portal vein suggests heart disease, and that retrograde transsinusoidal transmission of atrial pulsations is the mechanism. We noninvasively investigated portal vein pulsatility (PVP) in normal subjects and in patients with cardiac and liver disease, and performed invasive studies in cirrhotic humans and normal pigs. We found that accentuated PVP occurred in some normal subjects and in some patients with cirrhosis, and that mechanisms other than transsinusoidal transmission of atrial pulsations contributed to PVP. Determinants of PVP may include pulsatile portal inflow, transmission of pulsations from the vena cava (IVC) and location of the Doppler sample volume relative to the IVC.