Sequential Blood Collection from Inferior Vena Cava Followed by Portal Vein to Evaluate Gut Microbial Metabolites in Mice.

Gut microbial products are known to act both locally within the intestine and get absorbed into circulation, where their effects can extend to numerous distant organ systems. Short-chain fatty acids (SCFA) are one class of metabolites produced by gut microbes during the fermentation of indigestible dietary fiber. They are now recognized as important contributors to how the gut microbiome influences extra-intestinal organ systems via the gut-lung, gut-brain, and other gut-organ axes throughout the host. SCFAs are absorbed from the colon, through intestinal tissue, into the portal vein (PV). They then pass through the liver, and are consumed in various organs such as the brain, muscle, adipose tissue, and lungs. SCFAs are most easily measured in the expelled fecal material however, more accurate measurements have been obtained from intra-colonic fecal contents. Here we propose that sampling PV and systemic circulating plasma of a single subject may be preferable for studying the absorption, transport, and systemic levels of SCFAs in mice. We present a new technique for efficient blood sampling from the PV and inferior vena cava (IVC) that allows for the collection of relatively large volumes of blood from the portal and systemic circulations. This is accomplished by ligating the PV, thereby allowing for the dilation or enlargement of the PV as it backfills from the mesenteric veins that drain into it. Using this method, we were able to improve the rate of successful collection as well as the total amount of blood collected (up to 0.3 mL from IVC and 0.5 mL from PV).

A comparative analysis of deep learning and hybrid iterative reconstruction algorithms with contrast-enhancement-boost post-processing on the image quality of indirect computed tomography venography of the lower extremities.

PURPOSE: To examine whether there is a significant difference in image quality between the deep learning reconstruction (DLR [AiCE, Advanced Intelligent Clear-IQ Engine]) and hybrid iterative reconstruction (HIR [AIDR 3D, adaptive iterative dose reduction three dimensional]) algorithms on the conventional enhanced and CE-boost (contrast-enhancement-boost) images of indirect computed tomography venography (CTV) of lower extremities. MATERIALS AND METHODS: In this retrospective study, seventy patients who underwent CTV from June 2021 to October 2022 to assess deep vein thrombosis and varicose veins were included. Unenhanced and enhanced images were reconstructed for AIDR 3D and AiCE, AIDR 3D-boost and AiCE-boost images were obtained using subtraction software. Objective and subjective image qualities were assessed, and radiation doses were recorded. RESULTS: The CT values of the inferior vena cava (IVC), femoral vein ( FV), and popliteal vein (PV) in the CE-boost images were approximately 1.3 (1.31-1.36) times higher than in those of the enhanced images. There were no significant differences in mean CT values of IVC, FV, and PV between AIDR 3D and AiCE, AIDR 3D-boost and AiCE-boost images. Noise in AiCE, AiCE-boost images was significantly lower than in AIDR 3D and AIDR 3D-boost images ( P < 0.05). The SNR (signal-to-noise ratio), CNR (contrast-to-noise ratio), and subjective scores of AiCE-boost images were the highest among 4 groups, surpassing AiCE, AIDR 3D, and AIDR 3D-boost images (all P < 0.05). CONCLUSION: In indirect CTV of the lower extremities images, DLR with the CE-boost technique could decrease the image noise and improve the CT values, SNR, CNR, and subjective image scores. AiCE-boost images received the highest subjective image quality score and were more readily accepted by radiologists.

Proton-beam Therapy for Locally Advanced Hepatocellular Carcinoma With Inferior Vena Cava Tumor Thrombus: Case Report.

BACKGROUND/AIM: We report on a case of locally advanced hepatocellular carcinoma (HCC) accompanied by an inferior vena cava tumor thrombus (IVCTT), treated successfully with proton-beam therapy (PBT). CASE REPORT: A 63-year-old male presented with a primary, single HCC with IVCTT, without metastasis to the intrahepatic region, lymph nodes, or distant organs. The clinical staging was identified as T4N0M0 Stage IIIB. The patient's liver function was classified as Child-Pugh class A (score: 6), with a modified albumin-bilirubin (mALBI) grade of 2a. The patient had liver cirrhosis due to non-alcoholic steatohepatitis. Magnetic resonance imaging revealed a nodular tumor measuring 13.2×8.9×9.8 cm across segments 1, 6, 7, and 8, along with IVCTT. The patient received PBT, with a total dose of 72.6 Gy (relative biological effectiveness) delivered in 22 fractions. Throughout the PBT treatment, the patient experienced no acute toxicities and completed the therapy as planned. Twelve months following PBT, the patient was alive without evidence of local recurrence, lymph node involvement, or distant organ metastasis. The only late toxicity observed was a mild worsening of the mALBI grade. CONCLUSION: We observed a favorable local response with manageable toxicities in a patient with locally advanced HCC and IVCTT treated with PBT. While this is a single case report, our findings suggest that PBT could be considered a viable treatment option for HCC with IVCTT.

A Morphometric Study of Cadavers for the Anterior Approach to the Lower Lumbar Spine.

AIM: To explore the relationship between the retroperitoneal vasculature and anterior surface of the lower spine, and to establish values for aiding in prediction of the pertinence of anterior approach at the L4-L5 and L5-S1 intervertebral discs. MATERIAL AND METHODS: The study included 13 fresh human cadavers. After exploration of the abdominal cavity and removal of the visceral organs, the vasculature, and anterior spinal surface were revealed beneath the lower extension of the perirenal fascia. Morphometric measurements of the great vessels and the intervertebral discs were obtained. All measurements were analyzed and presented as mean and standard deviation. Differences in the values between sexes were assessed. RESULTS: The anterior height of the L4-L5 and L5-S1 intervertebral disc was 6.8 ± 0.81 mm and 6.7 ± 0.99 mm, respectively. The widths of the aorta, inferior vena cava, right and left common iliac arteries, and right, and left common iliac veins were 16.4 ± 3.58, 20.6 ± 3.36, 11.5 ± 2.32, 11.5 ± 2.43, 14.7 ± 3.13, and 15.5 ± 3.27 mm, respectively. The mean aortic bifurcation angle was 45.5°. The aortic bifurcation was located above the lower endplate of the L4 vertebrae in 53.8% of the cadavers. The area of the interarterial and interiliac trigones was 14.6 ± 5.33 cm < sup > 2 < /sup > and 7.1 ± 4.35 cm2, respectively. No statistically significant differences were noted between the sexes. CONCLUSION: An elaborate radiological examination of the vasculature should be performed prior to surgery to avoid unwanted vascular complications during the anterior approach. Knowing the area of the interarterial and interiliac triangles and the aortic bifurcation location could be aid in assessing the safe working zone.

Time-Dependent Sequential Changes of IL-10 and TGF-ß1 in Mice with Deep Vein Thrombosis.

OBJECTIVES: To detect the expression changes of interleukin-10 (IL-10) and transforming growth factor-ß1 (TGF-ß1) during the development of deep vein thrombosis in mice, and to explore the application value of them in thrombus age estimation. METHODS: The mice in the experimental group were subjected to ligation of inferior vena cava. The mice were sacrificed by excessive anesthesia at 1 d, 3 d, 5 d, 7 d, 10 d, 14 d and 21 d after ligation, respectively. The inferior vena cava segment with thrombosis was extracted below the ligation point. The mice in the control group were not ligated, and the inferior vena cava segment at the same position as the experimental group was extracted. The expression changes of IL-10 and TGF-ß1 were detected by immunohistochemistry (IHC), Western blotting and real-time qPCR. RESULTS: IHC results revealed that IL-10 was mainly expressed in monocytes in thrombosis and TGF-ß1 was mainly expressed in monocytes and fibroblast-like cells in thrombosis. Western blotting and real-time qPCR showed that the relative expression levels of IL-10 and TGF-ß1 in each experimental group were higher than those in the control group. The mRNA and protein levels of IL-10 reached the peak at 7 d and 10 d after ligation, respectively. The mRNA expression level at 7 d after ligation was 4.72±0.15 times that of the control group, and the protein expression level at 10 d after ligation was 7.15±0.28 times that of the control group. The mRNA and protein levels of TGF-ß1 reached the peak at 10 d and 14 d after ligation, respectively. The mRNA expression level at 10 d after ligation was 2.58±0.14 times that of the control group, and the protein expression level at 14 d after ligation was 4.34±0.19 times that of the control group. CONCLUSIONS: The expressions of IL-10 and TGF-ß1 during the evolution of deep vein thrombosis present time-dependent sequential changes, and the expression levels of IL-10 and TGF-ß1 can provide a reference basis for thrombus age estimation.

Computed tomographic reference ranges of intrathoracic caudal vena cava ratios in sedated adult dogs without cardiac, pulmonary, or hypovolemic disease.

BACKGROUND: Radiographic assessment of the intrathoracic caudal vena cava (CVC) is commonly used to evaluate hemodynamic status in veterinary patients without and with pulmonary, pericardial, or right-sided cardiac diseases. Many of these patients are now commonly evaluated with computed tomography (CT) in both emergency and referral settings. Traditional radiographic ratios in dogs, particularly the CVC height/aorta height (CVC/Ao) ratio, are often extrapolated to CT in order to determine if the CVC is normal in size. OBJECTIVES: The first goal of this retrospective study was to create an objective measurement method to evaluate the size of the CVC via CT. The second goal was to report normal CVC ratio values in both sagittal and transverse CT images. METHODS: The traditional lateral radiographic CVC ratios were extrapolated to similar ratios obtained from sagittal CT images in stable, sedated adult canine patients without known cardiac or pulmonary disease. Additionally, new methods of canine CVC ratios using transverse CT images were defined using vessel height and area. Mean, standard deviation, and 95% confidence intervals (CIs) of the CVC ratios in transverse and sagittal CT images were calculated to determine normal reference ranges. RESULTS: Ratio agreement from observers of different skill levels was moderate to excellent. Sagittal CT CVC/Ao mean was 1.07 ± 0.17 with a CI of 0.71.42. The mean and CI of transverse CT CVC/Ao height and area were 1.14 ± 0.27 and 0.781.44 and 1.36 ± 0.59 and 0.641.94, respectively. CONCLUSIONS: Application of normal sagittal and transverse CT ratio values in canine patients with and without hypotension, pulmonary, pericardial, or right-sided cardiac diseases is necessary to determine the clinical usefulness of these ratios.

Rodent Inferior Vena Cava Venoplasty Balloon Model.

Balloon venoplasty is a commonly used clinical technique to treat deep vein stenosis and occlusion as a consequence of trauma, congenital anatomic abnormalities, acute deep vein thrombosis (DVT), or stenting. Chronic deep venous obstruction is histopathologically characterized by thrombosis, fibrosis, or both. Currently, no direct treatment is available to target these pathological processes. Therefore, a reliable in vivo animal model to test novel interventions is necessary. The rodent survival inferior vena cava (IVC) venoplasty balloon model (VBM) allows the study of balloon venoplasty in non-thrombotic and post-thrombotic conditions across multiple time points. The local and systemic effect of coated and uncoated venoplasty balloons can be quantified via tissue, thrombus, and blood assays such as real-time polymerase chain reaction (RT-PCR), western blot, enzyme-linked immunosorbent assay (ELISA), zymography, vein wall and thrombus cellular analysis, whole blood and plasma assays, and histological analysis. The VBM is reproducible, replicates surgical human interventions, can identify local vein wall-thrombi protein changes, and allows multiple analyses from the same sample, decreasing the number of animals required per group.

A Case of Non-Seminomatous Germ Cell Tumor Complicated by Tumor Thrombus in an Active Duty Soldier.

Testicular malignancies commonly affect adolescent and young adult males. Although they tend to respond well to cisplatin-based chemotherapy with excellent overall survival, complications such as inferior vena cava tumor thrombus are rare and can be associated with high morbidity and mortality. We present a case of tumor thrombus in a 21-year-old active duty male with a newly diagnosed stage IIIB non-seminomatous germ cell tumor presenting with extensive left lower extremity swelling. Ultrasound with Doppler was notable for significant thrombus of the left common femoral, femoral, and popliteal vein. Computed tomography imaging revealed extensive thrombus of the inferior vena cava, left iliac veins, and left gonadal vein with sparing of the left renal vein. Endovascular thrombectomy was performed with pathologic analysis confirming the presence of malignant cells consistent with tumor thrombus. The patient continued subsequent non-seminomatous germ cell tumor treatment without complications.

Unlocking the Potential of VExUS in Assessing Venous Congestion: The Art of Doing It Right.

BACKGROUND: Congestion, marked by elevated cardiac filling pressures and their repercussions, is a contributing factor to morbidity and mortality in heart failure and critical illness. Relying on traditional methods for bedside evaluation often leads to inadequate decongestion and increased hospital readmissions. Point-of-care ultrasound (POCUS), particularly multi-organ POCUS, including the Venous Excess Ultrasound (VExUS) score, offers a promising approach in this scenario. VExUS enables the quantification of systemic venous congestion, aiding in fluid overload states by assessing inferior vena cava and venous Doppler waveforms. SUMMARY: This comprehensive review delves into the latest developments in comprehending and evaluating congestion, shedding light on technical intricacies to enhance the effective application of VExUS. Recent studies emphasize the importance of evaluating signs of hemodynamic congestion before administering intravenous fluids, highlighting the concept of "fluid tolerance." Moreover, VExUS-guided decongestion significantly improves decongestion rates in acute decompensated heart failure patients with acute kidney injury. Newer studies also highlight the prognostic implications of VExUS in the general ICU cohorts not confining to cardiac surgery patients. However, performing VExUS without understanding technical pitfalls may lead to clinical errors. Technical considerations in performing VExUS include nuances related to inferior vena cava and internal jugular vein ultrasound and familiarity with Doppler principles, optimal settings, and artifacts. Additionally, local structural alterations such as those seen in liver and kidney disease impact Doppler waveforms, emphasizing the need for careful interpretation. KEY MESSAGE: Overall, VExUS presents a valuable tool for assessing congestion and guiding management, provided clinicians are familiar with its technical complexities and interpret findings judiciously.

Impact of Left Renal Vein Ligation on Renal Function Following En Bloc Resection of Segmental Inferior Vena Cava and Right Kidney.

BACKGROUND: Renal function after left renal vein (LRV) ligation following en bloc resection of segmental inferior vena cava (IVC) and right kidney is understudied. We assessed the impact of LRV ligation on postoperative renal function following en bloc resection of segmental IVC and right kidney. METHODS: We retrospectively reviewed 28 patients who underwent LRV ligation during en bloc resection of segmental IVC and right kidney. Patient demographics, tumor characteristics, intraoperative factors, complications, length of hospital and intensive care unit (ICU) stay, and patient survival were collected. Pre- and postoperative renal function was retrospectively analyzed. RESULTS: Twenty patients underwent robot-assisted surgery and eight patients underwent open surgery. The median operative time was 162 min and estimated blood loss was 350 mL. Ten patients had normal renal function and 12 patients had an initial increase in creatinine but improved gradually. Six patients developed acute renal failure; five patients gradually recovered in 5-32 days after temporary hemodialysis. Renal replacement therapy significantly correlated with maximal anterior-posterior diameter of the LRV (p = 0.001). Complications were observed in 11 cases, four of which were Clavien-Dindo grades I-II. Thirteen patients were alive with no recurrence, nine patients were alive with metastasis, and six cases died during the follow-up period. CONCLUSIONS: LRV ligation following en bloc resection of segmental IVC and right kidney is feasible, with no significant long-term impact on renal function. The maximum anterior-posterior diameter of the LRV is a reliable method for predicting renal replacement therapy in the absence of collateral circulation.

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.

Impact of Breathing Control Training Program on sonographic quantification of abdominal vasculature.

OBJECTIVES: To compare vascular scanning parameters (vessel diameter, peak systolic velocity, end-diastolic velocity, and resistive index) and scanning time before and after breathing control training program for selected abdominal vessels. METHODS: This study was pre and post quasi-experimental. The researchers designed a breathing training program that gives participants instructions through a video describing breathing maneuvers. Data were collected at the ultrasound laboratory/College of Health and Rehabilitation Sciences in Princess Nourah bint Abdul Rahman University, Riyadh, Saudi Arabia from January 2023 to November 2023. About 49 volunteers at the university participated in the study. Scanning was performed two times for the right renal artery, upper abdominal aorta, inferior vena cava, and superior mesenteric artery. Scanning time was measured before and after the program as well. A paired sample t-test was used to compare the parameters means and time before and after the program. RESULTS: The program had a significant effect on the following parameters: right renal artery peak systolic velocity (p=0.042), upper abdominal aortic peak systolic velocity, and resistive index (p=0.014, p=0.014 respectively), superior mesenteric artery and inferior vena cava diameters (p=0.010 and p=0.020). The scanning time was reduced significantly (p<0.001). CONCLUSION: The breathing training program saves time and improves ultrasound measurement quality. Hospitals and health centers should consider the importance of breathing control training programs before abdominal scanning.

CT findings of an incidental segmental aplasia of the caudal vena cava with azygos continuation in a guinea pig (Cavia porcellus).

Background: Segmental aplasia of the caudal vena cava (CVC) with azygos continuation is a congenital malformation macroscopically described in mammals including humans, dogs, and rodents. It is usually detected as an incidental finding and the final diagnosis is reached by computed tomography (CT), fluoroscopy, or post-mortem dissection. Case Description: A 3-year-old guinea pig (Cavia porcellus) presented with subacute dyspnea. A computed tomographic examination was performed for the evaluation of subtle pulmonary changes previously suspected on conventional radiography, and a segmental aplasia of the CVC with azygos continuation was identified as an incidental finding. Conclusion: According to database negative results, this is the first report describing a segmental aplasia of the CVC and azygos continuation in a guinea pig by CT.

Perioperative outcomes of utilizing infrahepatic inferior vena cava clamping and Pringle maneuver during hepatectomy: a meta-analysis.

PURPOSE: Intraoperative bleeding during hepatectomy is primarily controlled through anaesthesiological interventions or surgical techniques such as Pringle maneuver (PM). Infrahepatic IVC clamping (IIVCC) is an alternative surgical technique to reduce central venous pressure and prevent retrograde hepatic venous bleeding. The aim of the meta-analysis was to compare IIVCC+PM with PM alone in terms of intraoperative outcomes and perioperative complications. METHODS: Medline, Cochrane Library, Scopus, Web of Science, and EMBASE were searched for comparative studies till 16.04.2024, resulting in 679 articles, of which eight studies met inclusion criteria. Data on patient demographics, surgical technique, and perioperative outcomes was assessed. Cochrane Risk of Bias 2.0 (RoB 2.0) Tool and Newcastle-Ottawa Scale (NOS) were used for risk of bias assessment. RESULTS: Two randomized controlled trials, one prospective, and five retrospective cohort studies with 358 patients in IIVCC+PM and 397 patients in PM alone group were included. IIVCC+PM resulted in significantly greater CVP reduction, less intraoperative blood loss (MD (95% CI) = - 233.03 (- 360.48 to - 105.58), P < 0.001), and less intraoperative blood transfusion (OR (95% CI) = 0.38 (0.25 to 0.57), P < 0.001) compared to PM alone. The two groups had comparable total operative time, transection time and total intraoperative fluid infusion. Patients undergoing IIVCC+PM had significantly shorter length of stay (MD (95% CI) = - 0.63 days (- 1.21 to - 0.05 days), P = 0.03) and overall complication rates (OR (95% CI) = 0.63 (0.43-0.92), P = 0.02) compared to PM alone group. CONCLUSION: The utilization of IIVCC along with PM during liver resection may be beneficial in reducing intraoperative bleeding and blood transfusion without adversely influencing operative times or perioperative outcomes compared to PM alone.

Quantifying Inferior Vena Cava Compliance and Distensibility in an In Vivo Ovine Model Using 3D Angiography.

Synthetic vascular grafts overcome some challenges of allografts, autografts, and xenografts but are often more rigid and less compliant than the native vessel into which they are implanted. Compliance matching with the native vessel is emerging as a key property for graft success. The current gold standard for assessing vessel compliance involves the vessel's excision and ex vivo biaxial mechanical testing. We developed an in vivo method to assess venous compliance and distensibility that better reflects natural physiology and takes into consideration the impact of a pressure change caused by flowing blood and by any morphologic changes present. This method is designed as a survival procedure, facilitating longitudinal studies while potentially reducing the need for animal use. Our method involves injecting a 20 mL/kg saline bolus into the venous vasculature, followed by the acquisition of pre and post bolus 3D angiograms to observe alterations induced by the bolus, concurrently with intravascular pressure measurements in target regions. We are then able to measure the circumference and the cross-sectional area of the vessel pre and post bolus. With these data and the intravascular pressure, we are able to calculate the compliance and distensibility with specific equations. This method was used to compare the inferior vena cava's compliance and distensibility in native unoperated sheep to the conduit of sheep implanted with a long-term expanded polytetrafluorethylene (PTFE) graft. The native vessel was found to be more compliant and distensible than the PTFE graft at all measured locations. We conclude that this method safely provides in vivo measurements of vein compliance and distensibility.

Tislelizumab combined with GT chemotherapy for intimal sarcoma of inferior vena cava: A case report.

RATIONALE: Intimal sarcoma of inferior vena cava (IVC) is a rare soft tissue sarcoma with no typical symptoms and specific imaging features in the early stage, and there is a lack of standardized treatment and methods. PATIENT CONCERNS: A 54-year-old female patient presented to Fenghua District People's Hospital with a post-active cough and hemoptysis and was subsequently referred to our hospital. DIAGNOSES: The patient was pathologically diagnosed as intimal sarcoma of IVC complicating multiple intrapulmonary metastases. Chest CT revealed left lung malignant tumor with multiple intrapulmonary metastases; while enhanced upper abdominal CT showed cancer embolus of IVC with extension to right atrium and bilateral renal veins. Besides, hematoxylin and eosin staining suggested intimal sarcoma of veins. Immunohistochemical staining showed positivity for PD-L1, Ki-67, CD31, Desmin and ERG. INTERVENTIONS: The patient initially received GT chemotherapy (gemcitabine injection + docetaxel). Then, immunotherapy (tislelizumab) was added based on the results of genetic testing (TP53 gene mutation). OUTCOMES: The disease was stabilized after receiving the treatment. LESSONS: Given the lack of characteristic clinical manifestations in patients with intimal sarcoma of IVC, imaging examination combined with immunohistochemical index were helpful for diagnosis of intimal sarcoma of IVC. Furthermore, the combination of tislelizumab and GT chemotherapy was feasible in such patients with positive PD-L1 expression and TP53 mutation.

New risk model by right ventricle - pulmonary arterial coupling and inferior vena cava from echocardiography in patients with conventional low-intermediate risk pulmonary artery hypertension under targeted treatment.

BACKGROUND: Accurately stratifying patients with pulmonary arterial hypertension (PAH) is very important, and traditional risk scores still have internal heterogeneity. This study aimed to construct a risk stratification model that can accurately identify clinical worsening (CW) events in conventional low-intermediate risk patients with pulmonary hypertension under targeted drug treatment by using echocardiographic parameters. METHODS: This study is a single-center, prospective study, including 105 PAH patients who underwent regular follow-up at Guangdong Provincial People's Hospital from October 2021 to April 2023. The primary endpoint was the occurrence of CW, including death, hospitalization due to pulmonary hypertension, escalation of targeted drug therapy, and worsening of PAH. The predictive value of the echocardiography-based three-strata risk model was assessed using Kaplan-Meier curves and COX regression analysis. RESULTS: A total of 98 PAH patients were ultimately included in this study. The median follow-up duration was 26 months (range 7-28 months). The echocardiography-based three-strata model included the ratio of tricuspid annular plane systolic excursion and pulmonary artery systolic pressure (TAPSE/PASP) and inferior vena cava (IVC). The echocardiography-based three-strata model had higher diagnostic value (C-index = .76) compared to the 2022 ESC/ERS three-strata model and four-strata model (C-index = .66 and C-index = .61, respectively). PAH patients with lower TAPSE/PASP and wider IVC showed a higher CW rate compared to patients with higher TAPSE/PASP and normal IVC (HR = 15.1, 95%CI:4.4-51.9, p < .001). CONCLUSION: The echocardiography-based three-strata model based on TAPSE/PASP and IVC can effectively improve the stratification of low-intermediate risk PAH patients under targeted treatment.