Impairment of change in diameter of the hepatic portion of the inferior vena cava: a sonographic sign of liver fibrosis or cirrhosis

Sound waves and solutions: Point-of-care ultrasonography for acute kidney injury in cirrhosis

This article delves into the intricate challenges of acute kidney injury (AKI) in cirrhosis, a condition fraught with high morbidity and mortality. The complexities arise from distinguishing between various causes of AKI, particularly hemodynamic AKI, in cirrhotic patients, who experience hemodynamic changes due to portal hypertension. The term "hepatocardiorenal syndrome" is introduced to encapsulate the intricate interplay among the liver, heart, and kidneys. The narrative emphasizes the often-overlooked aspect of cardiac function in AKI assessments in cirrhosis, unveiling the prevalence of cirrhotic cardiomyopathy marked by impaired diastolic function. The conventional empiric approach involving volume expansion and vasopressors for hepatorenal syndrome is critically analyzed, highlighting potential risks and variable patient responses. We advocate for a nuanced algorithm for AKI evaluation in cirrhosis, prominently featuring point-of-care ultrasonography (POCUS). POCUS applications encompass assessing fluid tolerance, detecting venous congestion, and evaluating cardiac function.

Point-of-care ultrasonography in cirrhosis-related acute kidney injury: How I do it

Discerning the etiology of acute kidney injury (AKI) in cirrhotic patients remains a formidable challenge due to diverse and overlapping causes. The conventional approach of empiric albumin administration for suspected volume depletion may inadvertently lead to fluid overload. In the recent past, point-of-care ultrasonography (POCUS) has emerged as a valuable adjunct to clinical assessment, offering advantages in terms of diagnostic accuracy, rapidity, cost-effectiveness, and patient satisfaction. This review provides insights into the strategic use of POCUS in evaluating cirrhotic patients with AKI. The review distinguishes basic and advanced POCUS, emphasizing a 5-point basic POCUS protocol for efficient assessment. This protocol includes evaluations of the kidneys and urinary bladder for obstructive nephropathy, lung ultrasound for detecting extravascular lung water, inferior vena cava (IVC) ultrasound for estimating right atrial pressure, internal jugular vein ultrasound as an alternative to IVC assessment, and focused cardiac ultrasound for assessing left ventricular (LV) systolic function and identifying potential causes of a plethoric IVC. Advanced POCUS delves into additional Doppler parameters, including stroke volume and cardiac output, LV filling pressures and venous congestion assessment to diagnose or prevent iatrogenic fluid overload. POCUS, when employed judiciously, enhances the diagnostic precision in evaluating AKI in cirrhotic patients, guiding appropriate therapeutic interventions, and minimizing the risk of fluid-related complications.

Acute kidney injury and point-of-care ultrasound in liver cirrhosis: redefining hepatorenal syndrome

Acute kidney injury (AKI) in patients with cirrhosis is a diagnostic challenge due to multiple and sometimes overlapping possible etiologies. Many times, diagnosis cannot be made based on case history, physical examination or laboratory data, especially when the nephrologist is faced with AKI with a hemodynamic basis, such as hepatorenal syndrome. In addition, the guidelines still include generalized recommendations regarding withdrawal of diuretics and plasma volume expansion with albumin for 48 h, which may be ineffective and counterproductive and may have iatrogenic effects, such as fluid overload and acute cardiogenic pulmonary edema. For this reason, the use of new tools, such as hemodynamic point-of-care ultrasound (PoCUS), allows us to phenotype volume status more accurately and ultimately guide medical treatment in a noninvasive, rapid and individualized manner.

Design and performance analysis of a new inferior vena cava filter

This study proposes a novel inferior vena cava filter (IVCF) design, "Lotus," aiming to enhance release stability and endothelialization. A catheter-filter-vessel model was established for IVCF property analysis, validated by comparing numerical simulations and in vitro tests. Lotus's mechanical properties were analyzed, and optimization suggestions are provided. Compared to existing clinical filters, Lotus demonstrates improved release stability and thrombus capture ability. This work suggests Lotus as a potential technical reference for improved IVCF treatment.

Correlation of Internal Jugular Vein Collapsibility With Central Venous Pressure in Patients With Liver Cirrhosis

We aimed to compare internal jugular vein and inferior vena cava ultrasonography as predictors of central venous pressure in cirrhotic patients. We performed ultrasound assessments of the internal jugular vein (IJV) and the inferior vena cava and then invasively measured central venous pressure (CVP). We then compared their correlation with CVP and performed area under the receiver operating characteristic curves to determine which had best sensitivity and specificity. IJV cross-sectional area collapsibility index at 30° correlated better with CVP ( r = -0.56, P < 0.001), and an IJV AP-CI at 30° ≤ 24.8% was better at predicting a CVP ≥8 mm Hg, with 100% sensitivity and 97.1% specificity. Thus, IJV point-of-care ultrasound might be superior than inferior vena cava point-of-care ultrasound as a predictor of CVP in cirrhotic patients.

Ultrasonographic Measurements of the Liver, Gallbladder Wall Thickness, Inferior Vena Cava, Portal Vein and Pancreas in an Urban Region, Malaysia

Background:

Ultrasonographic (USG) measurements of the liver length, gallbladder wall thickness (GBWT), diameters of the inferior vena cava (IVC), portal vein (PV), and pancreas are valuable and reliable in diagnosis hepatobiliary and pancreas conditions. This study is aimed to determine the normal values of liver length, GBWT, AP diameters of the IVC and PV, AP diameter of the head and body of the pancreas.

Methods:

A prospective cross–sectional study was carried out in this study. A total of the 408 participants were randomly recruited using a systematic method. According to the USG reports, the subjects who had normal USG report for liver, biliary system, and pancreas were described as normals, whereas the subjects who had hepatobiliary diseases such as fatty liver, liver cysts, hemangioma, cirrhosis, gallbladder wall thickening, acute cholecystitis, gallstones, and polyps were recorded as abnormal subjects.

Results:

Of the 408 participants with a mean of 52.6 ± 8.4 years old. Of those, 294 (72.1%) participants were normal and 114 (27.9%) subjects were reported as abnormal. More than half of the study population was males, 52.9% versus 47.1% of females. There was a significant difference of liver length, head, and body of the pancreas between genders (P = 0.004, 0.002, and P < 0.001, respectively). Moreover, the pancreatic body only was significantly correlated with age (P = 0.026). There also was a significant difference of the liver length, head, and body of the pancreas between normal and abnormal subjects (P < 0.001, P = 0.007, and P < 0.001).

Conclusion:

Liver length, diameter of the head, and body of the pancreas were significantly associated with gender and hepatobiliary diseases. In addition, only the diameter of the body of the pancreas was significantly correlated with age.

Automated Ultrasound Measurement of the Inferior Vena Cava: An Animal Study

Because of continuous movement and variation in diameter of the inferior vena cava (IVC) with respiration, the measurements on IVC are labor-intensive and with considerable inter-operator variations. Some computer-assisted techniques have been developed to track the movement of the IVC semi-automatically. However, existing methods predominantly rely on reference marker selection and require many manual inputs. In this study, we developed a cross-correlation (CC)-based method for automated IVC movement tracking and measurement, which requires minimal manual input and avoids manual selection of reference markers. Based on the CC method, two approaches, named direct and relative approaches, were used to calculate the maximum, minimum, and variation of the IVC diameter, and compared with the manual measurement. Fifty-four ultrasound cine-loops collected from nine pigs were tested. The results reveal that both the proposed approaches were well agreed with the manual measurement. The errors of the direct approach were less than 9%, while those of relative approach were as high as 26.7%. It is concluded that the proposed direct approach is superior for IVC diameter measurements, which can be comparable with manual counterpart, serving as an alternative to traditional IVC measurement.

Feasibility of Using a Pocket-Sized Ultrasound Device to Measure the Inferior Vena Cava Diameter of Patients With Heart Failure in the Community Setting: A Pilot Study

Background: The incidence of heart failure as well as its treatment costs and rehospitalization rates are increasing worldwide. Physical assessment of elderly patients with heart failure living in their homes is challenging for community nurses. Pocket-sized echocardiographs will be useful for assessing the condition of the patients with heart failure during home-visit care. Objectives: This pilot study aimed to examine the feasibility of measuring the inferior vena cava (IVC) diameter using a pocket-sized ultrasound device. Methods: Nursing students were trained to use the pocket-sized ultrasound device (PUSD) for measuring the inferior vena cava diameter of a healthy subject. We evaluated the accuracy and rapidity of the nursing students' measurements compared with those of an expert sonographer. Results: In total, 83.3% of the participants accurately visualized the IVC using the PSUD. There was no significant difference in the mean IVC diameter between that measured by the students and the sonographer. In total, 25% of the participants accurately measured the IVC diameter. The mean measurement time was 201 seconds. Conclusion: Our training program allowed the participants to accurately visualize the IVC using the PSUD. However, these results on accuracy and measurement time still need to be improved before community nurses can use the PSUD during home visits.

Non-invasive Estimation of Right Atrial Pressure Using Inferior Vena Cava Echography

The pulsatility of the inferior vena cava (IVC) reflects the volume status and central venous pressure of patients. The standard clinical indicator of IVC pulsatility is the caval index (CI), measured from ultrasound recordings. However, its estimation is not standardized and is vulnerable to artifacts, mostly because of IVC movements during respiration. Thus, we used a (recently patented) semi-automated method that tracks IVC movements and averages the CI across an entire section of the vein, which provides a more stable indication of pulsatility. This algorithm was used to estimate the CI, pulsatility indicators reflecting either respiratory or cardiac stimulation and the mean diameter of the IVC. These IVC indices, together with anthropometric information, were used as potential features to build an innovative model for the estimation of the right atrial pressure (RAP) recorded from 49 catheterized patients. An exhaustive search was carried out for the best among all possible models that could be obtained by using combinations of these features. The model with minimum estimation error (tested with a leave-one-out approach) was selected. This model estimated RAP with an error of about 3.6 ± 2.6 mm Hg (mean ± standard deviation); the error when using only operator measured variables, without software, was about 4.0 ± 2.5 mm Hg. These promising results underline the need for further study of our RAP estimation method on a larger data set.

Noninvasive estimation of intravascular volume status in cirrhosis by dynamic size and collapsibility indices of the inferior vena cava using bedside echocardiography

Background and Aim

Echocardiographic assessment of the inferior vena cava diameter (IVCD) and collapsibility index (IVCCI) is a noninvasive estimate of intravascular volume status (IVS) but requires validation for cirrhosis. We evaluated IVC dynamics in cirrhosis and correlated it with conventional tools such as central venous pressure (CVP), pulmonary capillary wedge pressure (PCWP), and right atrial pressure (RAP).

Methods

A total of 673 consecutive cirrhotic patients were screened by echocardiography, and 125 patients underwent right heart catheterization with recording of hepatic venous pressure gradient (HVPG), RAP, pulmonary artery (PA) pressure, and PCWP. CVP data were available for 80 (64%) patients, and finally, 76 patients (84% male, 50% ethanol related, mean age 52.1 years, 57.8% with ascites) with complete data were enrolled.

Results

The mean CVP measured was 12.8 ± 4.8 mmHg, and IVCCI was 29.5 ± 10.9%. The IVCD ranged from 0.97 to 2.26 cm and from 0.76 to 1.84 cm during expiration and inspiration, respectively, with a mean of 1.8 ± 0.9 cm. The mean IVCD correlated with RAP (r = 0.633, P = 0.043) but not with HVPG (r = 0.344, P = 0.755), PCWP (r = 0.562, P = 0.072), or PA pressure (r = 0.563, P = 0.588). A negative linear correlation was observed between the CVP and the IVCCI (r = −0.827, P = 0.023) in all patients and substratified for those with (r = −0.748, P = 0.039) and without ascites (r = −0.761, P = 0.047). A positive correlation was observed between CVP and IVCD_max (r = 0.671, P = 0.037) and IVCD_min (r = 0.612, P = 0.040).

Conclusions

IVCD and collapsibility index provides noninvasive IVS assessment, independent of HVPG or ascites, with the potential for calculating fluid requirements in cirrhosis.

Gallbladder Scalloping, Mammillated Caudate Lobe, and Inferior Vena Cava Scalloping: Three Novel Ultrasound Signs of Cirrhosis

PURPOSE

We aimed to present three new ultrasound signs-gallbladder scalloping, mammillated caudate lobe, and inferior vena cava scalloping-and determine their accuracy in diagnosing liver cirrhosis.

MATERIALS AND METHODS

A total of 201 consecutive patients with a history of chronic liver disease who had undergone ultrasound imaging and liver biopsy were identified. A senior ultrasound radiologist blindly reviewed the ultrasound examinations. Specificity, sensitivity, positive predictive value, and negative predictive value of diagnosing cirrhosis were calculated for all evaluated ultrasound signs and selected combinations of signs, using the liver biopsy results as the reference standard.

RESULTS

Of the 201 patients, 152 (76%) had either pathology-proven cirrhosis or significant fibrosis. Caudate lobe hypertrophy was the most specific (88%) and most positive predictor (90%) for cirrhosis, whereas mammillated caudate lobe was the most sensitive (78%). Inferior vena cava scalloping was the most specific (78%) of the three proposed ultrasound signs. When signs were combined, the presence of either gallbladder scalloping or liver surface nodularity was highly sensitive for cirrhosis (87%), whereas the presence of either gallbladder scalloping or inferior vena cava scalloping with caudate lobe hypertrophy was highly specific (93%).

CONCLUSIONS

Gallbladder scalloping, mammillated caudate lobe, and inferior vena cava scalloping are three novel signs that improve the accuracy of ultrasound in diagnosing cirrhosis.

Automated Identification and Localization of the Inferior Vena Cava Using Ultrasound: An Animal Study

Ultrasound measurement of the inferior vena cava (IVC) is widely implemented in the clinic. However, the process is time consuming and labor intensive, because the IVC diameter is continuously changing with respiration. In addition, artificial errors and intra-operator variations are always considerable, making the measurement inconsistent. Research efforts were recently devoted to developing semiautomated methods. But most required an initial identification of the IVC manually. As a first step toward fully automated IVC measurement, in this paper, we present an intelligent technique for automated IVC identification and localization. Forty-eight ultrasound data sets were collected from eight pigs, each of which included two frames in B-mode and color mode (C-mode) collected at the inspiration, and two cine loops in B-mode and C-mode. Static and dynamic automation algorithms were applied to the data sets for identifying and localizing the IVC. The results were evaluated by comparing with the manual measurement of experienced clinicians. The automated approaches successfully identified the IVC in 47 cases (success rate: 97.9%). The automated localization of the IVC is close to the manual counterpart, with the difference within one diameter. The automatically measured diameters are close to those measured manually, with most differences below 15%. It is revealed that the proposed method can automatically identify the IVC with high success rate and localize the IVC with high accuracy. But the study with high accuracy was conducted under good control and without considering difficult cases, which deserve future explorations. The method is a first step toward fully automated IVC measurement, which is suitable for point-of-care applications.

Systemic vascular resistance and fluid status in patients with decompensated liver cirrhosis with or without functional renal failure in Egypt

BACKGROUND

Functional renal failure and cardiovascular dysfunction are common complications of liver cirrhosis. This study aimed to evaluate cardiac performance, systemic vascular resistance (SVR) and fluid status in patients with decompensated liver cirrhosis either with or without functional renal failure.

METHODS

Sixty patients diagnosed as having decompensated liver cirrhosis were divided into two groups. Group 1 included 30 patients with decompensated liver cirrhosis with ascites and with creatinine values ≤ 1.5 mg/dl. Group 2 included 30 azotemic decompensated cirrhotic patients with diagnostic criteria of hepatorenal syndrome (HRS). Also, 20 healthy subjects, of matched age and sex to the Group 1 and Group 2 patients, were included in the study as the control group. All patients and normal controls were subjected to clinical examination, laboratory evaluation, ECG, abdominal ultrasonography and echocardiographic studies.

RESULTS

The echocardiographic and ECG data showed significant increase in LAD (P<0.01, P<0.01), AoD (P<0.05, P<0.01), interventricular septum thickness (IVST) (P<0.01, P<0.01), posterior wall thickness (PWT) (P<0.01, P<0.01), EDD (P<0.01, P<0.01), ESD (P<0.05, P<0.01), left ventricular (LV) mass (P<0.01, P<0.01), and Corrected QT (QTc) (P<0.01, P<0.01) interval with significant decrease in SVR (P<0.01, P<0.01). Additionally, there was significant decrease in IVC diameter in both patients groups compared to the control group (P<0.01, P<0.01).

CONCLUSION

Patients with decompensated liver cirrhosis have low SVR, and Doppler echocardiography provides an easy noninvasive tool to assess this finding. Also, these patients demonstrate small inferior vena cava (IVC) diameter with normal collapsibility, which indicates low effective plasma volume. Measuring IVC diameter and collapsibility are of value in the prediction of intravascular fluid status in liver cirrhosis. This is especially true with renal dysfunction. Early addition of oral vasoconstrictors in decompensated patients may correct the SVR and circulatory dysfunction and hinder HRS occurrence.

Semi-automated tracking and continuous monitoring of inferior vena cava diameter in simulated and experimental ultrasound imaging

Assessment of respirophasic fluctuations in the diameter of the inferior vena cava (IVC) is detrimentally affected by its concomitant displacements. This study was aimed at presenting and validating a method to compensate for IVC movement artifacts while continuously measuring IVC diameter in an automated fashion (with minimal interaction with the user) from a longitudinal B-mode ultrasound clip. Performance was tested on both experimental ultrasound clips collected from four healthy patients and simulations, implementing rigid IVC displacements and pulsation. Compared with traditional M-mode measurements, the new approach systematically reduced errors in caval index assessment (range over maximum diameter value) to an extent depending on individual vessel geometry, IVC movement and choice of the M-line (the line along which the diameter is computed). In experimental recordings, this approach identified both the cardiac and respiratory components of IVC movement and pulsatility and evidenced the spatial dependence of IVC pulsatility. IVC tracking appears to be a promising approach to reduce movement artifacts and to improve the reliability of IVC diameter monitoring.

Inferior vena cava percentage collapse during respiration is affected by the sampling location: an ultrasound study in healthy volunteers

OBJECTIVES

Physicians are unable to reliably determine intravascular volume status through the clinical examination. Respiratory variation in the diameter of the inferior vena cava (IVC) has been investigated as a noninvasive marker of intravascular volume status; however, there has been a lack of standardization across investigations. The authors evaluated three locations along the IVC to determine if there is clinical equivalence of the respiratory percent collapse at these sites. The objective of this study was to determine the importance of location when measuring the IVC diameter during quiet respiration.

METHODS

Measurements of the IVC were obtained during quiet passive respiration in supine healthy volunteers. All images were recorded in B-mode, with cine-loop adjustments in real time, to ensure that maximum and minimum IVC dimensions were obtained. One-way repeated-measures analysis of variance (ANOVA) was used for comparison of IVC measurement sites.

RESULTS

The mean (+/-SD) percentage collapse was 20% (+/-16%) at the level of the diaphragm, 30% (+/-21%) at the level of the hepatic vein inlet, and 35% (+/-22%) at the level of the left renal vein. ANOVA revealed a significant overall effect for location of measurement, with F(2,35) = 6.00 and p = 0.006. Contrasts showed that the diaphragm percentage collapse was significantly smaller than the hepatic (F(1,36) = 5.14; p = 0.03) or renal caval index (F(1,36) = 11.85; p = 0.002).

CONCLUSIONS

Measurements of respiratory variation in IVC collapse in healthy volunteers are equivalent at the level of the left renal vein and at 2 cm caudal to the hepatic vein inlet. Measurements taken at the junction of the right atrium and IVC are not equivalent to the other sites; clinicians should avoid measuring percentage collapse of the IVC at this location.

Hypovolemic shock evaluated by sonographic measurement of the inferior vena cava during resuscitation in trauma patients

BACKGROUND

Inferior vena cava (IVC) diameter immediately after fluid resuscitation has not yet been investigated in trauma patients with shock on arrival.

METHODS

Between June 2004 and May 2005, 30 trauma patients with hemorrhagic shock were prospectively investigated. Using ultrasound, we measured maximum anterior-posterior diameter of the IVC just below the diaphragm in the hepatic segment, in the expiratory phase. This was performed on arrival and when systolic blood pressure had been raised to over 90 mm Hg by fluid resuscitation in the emergency room. Subjects were divided into two groups: a transient responder group (n = 17) in which shock recurred after leaving the emergency room and a responder group (n = 13) in which blood pressure remained stable.

RESULTS

There were no significant differences between the two groups regarding age or gender, or regarding vital signs or IVC diameter on arrival. Average injury severity score in the transient responder group was significantly greater than that in the responder group. After fluid resuscitation, no significant intergroup differences were observed regarding vital signs. However, IVC diameter was significantly smaller in the transient responder group than in the responder group (6.5 +/- 0.5 mm; mean +/- SE vs. 10.7 +/- 0.7 mm, p < 0.05).

CONCLUSION

In trauma patients, inadequate dilatation of the IVC by fluid resuscitation, might indicate insufficient circulating blood volume despite normalization of blood pressure. In this small study, IVC diameter appeared a better predictor of recurrence of shock than blood pressure, heart rate, or arterial base excess. A larger prospective study is called for to clearly establish the sensitivity and specificity of this method.