Left Inferior Vena Cava Research Articles

Left inferior vena cava for device access of a leadless pacemaker.

Left inferior vena cava for device access of a leadless pacemaker.

A-056 Investigating Iodine Contrast Contamination in Cortisol and Aldosterone Samples

Abstract Background Primary aldosteronism (PA) is a condition characterized by hypertension resulting from excess secretion of aldosterone. PA caused by a unilateral aldosterone-producing adenoma can be treated with adrenalectomy but requires diagnosis by adrenal vein sampling (AVS). In this procedure, intravenous cosyntropin is administered to stimulate adrenal cortical secretion, followed by obtaining samples from the right and left adrenal veins and IVC. Laterization index is calculated by obtaining the aldosterone:cortisol ratio for each side, with a ratio cutoff ≥3 is used for confirmation. Iodinated contrast media facilitates visualization of catheter positioning during AVS and sometimes results in contamination of samples, evidenced by abnormal gel separator flotation (i.e. gel above plasma). This study had two aims: 1) to determine at what concentration contrast dye causes gel flotation and 2) discern whether contrast media interferes with our cortisol or aldosterone assays. Methods Gel flotation studies were performed by spiking pooled plasma samples with iohexol contrast media (Omnipaque 240, GE Healthcare) at concentrations ranging from 3%-10% v/v and aliquoting into fresh lithium heparin plasma separator tubes (BD, PSTs). Samples were then centrifuged and visually inspected for abnormal gel flotation. Contrast interference studies were performed using three pools of low (5 µg/dL), medium, (30 µg/dL), and high (55 µg/dL) cortisol concentrations. Sample pools were diluted with 20% contrast media or saline (control) and subsequently mixed at different ratios to create a range of dye concentrations (0.5%-18% v/v). Each mixture was assayed in triplicate for cortisol and aldosterone on a cobas e602 (Roche Diagnostics) and LIAISON XL (DiaSorin) immunoanalyzer, respectively. The total allowable error (TEa) was ±0.4 μg/dL or ±20% for cortisol and ±2 ng/dL or ±20% for aldosterone. Results Flotation of the gel separator was observed at a dye concentration of 4.5% v/v and greater. For the cortisol interference study, the bias was <5% for the three pools at all contrast media concentrations. Aldosterone was also measured in these pools, as bias could affect ratios calculated for PA. Aldosterone interference occurred at contrast dye concentrations ranging from 12%-20% v/v. An average positive bias of 34% was observed in aldosterone samples spiked with contrast media relative to the saline control. Compared to sample pool controls without added saline or dye, measurements for cortisol and aldosterone were 19%-22% and 16-25% lower in media- and saline-spiked samples (20% v/v), respectively, indicating a logical dilution effect. Conclusions Contrast dye contamination of AVS specimens can cause gel flotation in lithium heparin PSTs, preventing their analysis. The presence of contrast media at certain concentrations interfered with the DiaSorin aldosterone assay, leading to falsely elevated results. No cortisol assay interference occurred in the presence of contrast media but results were falsely decreased due to sample dilution. Samples collected during AVS may be contaminated with contrast dye causing gel flotation to occur. This is indicative of a minimum contrast media concentration of 4.5% v/v. Aldosterone:cortisol ratios may be inaccurate due to the positive aldosterone immunoassay bias with contrast media contamination. Care should be taken when reporting and interpreting AVS results with suspected contamination.

Impact of sympathetic hyperactivity induced by brain microglial activation on organ damage in sepsis with chronic kidney disease

BackgroundSympathetic nerve activity (SNA) plays a central role in the pathogenesis of several diseases such as sepsis and chronic kidney disease (CKD). Activation of microglia in the paraventricular nucleus of the hypothalamus (PVN) has been implicated in SNA. The mechanisms responsible for the adverse prognosis observed in sepsis associated with CKD remain to be determined. Therefore, we aimed to clarify the impact of increased SNA resulting from microglial activation on hemodynamics and organ damage in sepsis associated with CKD.Methods and resultsIn protocol 1, male Sprague–Dawley rats underwent either nephrectomy (Nx) or sham surgery followed by cecal ligation and puncture (CLP) or sham surgery. After CLP, Nx-CLP rats exhibited decreased blood pressure, increased heart rate, elevated serum creatinine and bilirubin levels, and decreased platelet count compared to Nx-Sham rats. Heart rate variability analysis revealed an increased low to high frequency (LF/HF) ratio in Nx-CLP rats, indicating increased SNA. Nx-CLP rats also had higher creatinine and bilirubin levels and lower platelet counts than sham-CLP rats after CLP. In protocol 2, Nx-CLP rats were divided into two subgroups: one received minocycline, an inhibitor of microglial activation, while the other received artificial cerebrospinal fluid (CSF) intracerebroventricularly via an osmotic minipump. The minocycline-treated group (Nx-mino-CLP) showed attenuated hypotensive and increased heart rate responses compared to the CSF-treated group (Nx-CSF-CLP), and the LF/HF ratio was also decreased. Echocardiography showed larger left ventricular dimensions and inferior vena cava in the Nx-mino-CLP group. In addition, creatinine and bilirubin levels were lower and platelet counts were higher in the Nx-mino-CLP group compared to the Nx-CSF-CLP group.ConclusionsIn septic rats with concomitant CKD, SNA was significantly enhanced and organ dysfunction was increased. It has been suggested that the mechanism of exacerbated organ dysfunction in these models may involve abnormal systemic hemodynamics, possibly triggered by activation of the central sympathetic nervous system through activation of microglia in the PVN.

Calculated Right Adrenal Vein Aldosterone Levels in Patients Undergoing Adrenal Vein Sampling: The Potential to Lateralize Despite Unsuccessful Selection of the Right Adrenal Vein

PurposeThe aim of this study was to use calculated aldosterone level in the right adrenal vein (RAV) (cAldoRAV) rather than measured level for identifying the dominant side of aldosterone secretion in patients with primary aldosteronism undergoing adrenocorticotropic hormone–stimulated adrenal venous sampling (AVS). Materials and MethodsPatients with primary aldosteronism who had successful AVS (selectivity index, >3) were studied. Based on the assumption that cortisol production from both adrenal glands is equal, aldosterone level in the RAV was calculated using the data from the left adrenal vein and inferior vena cava. The aldosterone level in the left adrenal vein (AldoLAV) compared with the cAldoRAV (AldoLAV:cAldoRAV ratio) was then used to determine the dominant side of aldosterone secretion compared with standard AVS interpretation using lateralization index (LI). LI ≥4 indicated unilateral disease, and LI ≤3 indicated bilateral disease. The LI between 3 and 4 was diagnosed as indeterminate. ResultsSixty-eight patients with concordant results between AVS and adrenal imaging study (32 were left-sided, 22 were right-sided, and 14 were bilateral) were selected for studying diagnostic performance. The AldoLAV:cAldoRAV ratio with the cutoff values of ≥3 and ≤0.33 could identify unilateral diseases (left-sided and right-sided disease, respectively) with 92.6% sensitivity and 100% specificity. ConclusionsThe calculated AldoLAV:cAldoRAV ratio can determine the dominant side of aldosterone secretion with high sensitivity and specificity when compared with standard AVS interpretation of measured levels. It provides an option for identification of unilateral and bilateral disease in select patients in whom right adrenal vein selection is unsuccessful.

HYDATID CYST IN CAUDATE LOBE OF LIVER- A THERAPEUTIC CHALLENGE

Background: Treatment of Echinococcal disease depends on the type, size, and location of the cyst, presence of complications, and the experience of the team. Treatment options include percutaneous treatments, surgery, anti-parasitic drugs, and follow-up without intervention. Objectives: To report a case of hydatid cyst located in caudate lobe of liver. Materials and Methods: A 32-year-female, presented with c/o of Pain in abdomen since 1 week localized to right hypochondrium. USG (A+P) was suggestive of hydatid cyst in caudate lobe of liver. MRI was suggestive of hydatid cyst of liver with abutment of left portal vein and IVC. Patient was first started on medical treatment for 6 weeks and then planned for laparoscopic hydatid cyst excision. Cyst was approached laproscopically and fluid aspirated followed by injection of 10% betadine solution (scolicidal) and then reaspirated. Endocyst was removed. The resultant cavity was plugged with omentum. Results: Patient was discharged on POD-3 on T. Albendazole 400 mg BD for 3 months and T. Praziquantal 600 mg once a week for 3 months. After 6 months, patient is symptomatically well and has no complaints or signs of recurrence at present. Conclusion: Minimally invasive laproscopic sugery has more or less replaced the conventional open surgical approach for cystic hydatidosis. Our case is unique due to its location in the caudate lobe of liver alongwith abutment and mild compression of IVC and portal vein which poses a therapeutic challenge to the surgeon. The caudate lobe of the liver is an anatomically complex liver segment. Its unique and intimate location with the hepatic hilum and inferior vena cava (IVC) coupled with its dual supply from both portal pedicles and direct venous drainage into the IVC make vascular control a particular challenge. Technically challenging cyst excision can be performed laparoscopically with its benefits of improved perioperative outcomes.

Extensive Left Sided Venous Thrombi and Bilateral Pulmonary Emboli in the Context of May-Thurner Syndrome for a Patient Presenting with Acute Flank Pain: A Case Report

May-Thurner syndrome is an underappreciated differential in the context of deep venous thrombosis. It is a symptomatic congenital abnormality resulting from compression of the left common iliac vein, sometimes also referred to as iliac vein compression syndrome in the literature. This case reports the presentation of a female with acute flank pain to the emergency department following a recent laparotomy for a complicated tubo-ovarian abscess. She was subsequently diagnosed with a sub-acute thrombus extending from the left common femoral vein into the left inferior vena cava, as well as new bilateral pulmonary emboli. As the patient had relative contraindications to thrombolysis, a shared decision was made with the vascular team to opt for conservative management only. In this instance, this included long-term oral anticoagulant therapy and compression stockings. This case asserts that clinicians should maintain a high index of suspicion for May-Thurner syndrome in the context of extensive left-sided thrombus formation.

Left Ventricular Geometry and Inferior Vena Cava Diameter Co-Modify the Risk of Cardiovascular Outcomes in Chronic Hemodialysis Patients.

Background and Objectives: Left ventricular hypertrophy (LVH) represents a significant cardiovascular risk in patients undergoing chronic hemodialysis (CHD). A large inferior vena cava diameter (IVCD), potentially indicative of fluid overload and a contributing factor to elevated cardiovascular risk, has not been sufficiently explored. Therefore, our study aims to gain further insights into this aspect. Materials and Methods: A retrospective cohort study enrolled patients receiving CHD in a single medical center with available echocardiography from October to December 2018. They were categorized into four groups based on LVH geometry and IVCD. Cox proportional hazard models assessed the risk of major adverse cardiovascular effects (MACEs) and cardiovascular and overall mortality after multivariate adjustments. Kaplan-Meier analysis depicted MACE-free events and survival during the follow-up time. Results: Of the 175 CHD patients, 38, 42, 45, and 50 exhibited small IVCD with eccentric and concentric LVH and large IVCD with eccentric and concentric LVH, respectively. Compared to small IVCD and eccentric LVH, large IVCD and eccentric LVH had the highest risk of MACEs, followed by large IVCD and concentric LVH (aHR: 4.40, 3.60; 95% CI: 1.58-12.23, 1.28-10.12, respectively). As for cardiovascular mortality, large IVCD and concentric LVH had the highest risk, followed by large IVCD and eccentric LVH, and small IVCD and concentric LVH. (aHR: 14.34, 10.23, 8.87; 95% CI: 1.99-103.35, 1.41-74.33; 1.01-77.87). The trend in overall mortality risk among the groups was similar to that of cardiovascular mortality. Conclusions: LVH geometry and IVCD co-modify the risk of MACEs and cardiovascular and overall mortality in CHD patients. The highest risk of MACEs is associated with large IVCD and eccentric LVH, while the highest risk of cardiovascular and overall mortality is linked with large IVCD and concentric LVH.

Liver Resection Under Total Hepatic Vascular Exclusion with In Situ Hypothermic Isolated Hepatic Perfusion for Advanced Liver Tumors.

Continuous dissection or simultaneous reconstruction of the hepatic vein (HV) and inferior vena cava (IVC) was achieved under total hepatic vascular exclusion (THVE) with in situ hypothermic isolated hepatic perfusion (HIHP) in two cases. CASE 1: The patient previously underwent liver resections with the right HV for colorectal liver metastasis (CRLM). This time, the CRLM had invaded the left HV and IVC, and five courses of FOLFILI plus ramucirumab were given, resulting in stable disease. Due to expected high HV pressure, liver parenchymal transection was started under THVE. Sub-segmentectomy with patch graft plasty of the IVC and reconstruction of the left HV using a jugular vein graft were performed under THVE and HIHP. This patient died at home 3 months after surgery; the cause of death was unknown. CASE 2: Hepatocellular carcinoma in the caudate lobe was in extensive contact with the roots of three main HVs and the IVC, and pressed the hepatocaval confluence, with high HV pressure expected. In addition, tumor thrombosis extended to both the main portal vein and the common bile duct, resulting in the inability to introduce chemotherapy. After tumor thrombectomy, liver parenchymal transection was started under THVE. Extended left hepatectomy with wedge resection, and primary suture of the right HV and IVC was performed under THVE and HIHP. Recurrence-free and overall survivals were 8 months (lung metastasis) and 31 months, respectively. In liver resection for liver tumors located in the hepatocaval confluence, THVE with HIHP is useful for ensuring the safety.

Effects of high-gravity acceleration forces and anti-gravity maneuver on the cardiac function of fighter pilots.

The fighter pilots exposed to high gravitational (G) acceleration must perform anti-G maneuvers similar to the Valsalva maneuver. However, the effects of high-G acceleration and anti-G maneuvers on cardiac function have rarely been studied. This study aimed to investigate the effects of high-G forces on cardiac function of fighter pilots. Fighter pilots who underwent regular health check-ups and echocardiography were included (n = 29; 100% men, 41 ± 10years old; mean flight time, 1821 ± 1186h). Trainees who had not experienced any flights were included in the control group (n = 16; 100% men, 36 ± 17years old). Echocardiographic data included left ventricular chamber size, systolic and diastolic functions, right ventricular systolic pressure (RVSP), inferior vena cava (IVC) collapsibility, and tricuspid annular plane systolic excursion (TAPSE). No significant differences in left ventricular ejection fraction, RVSP, or IVC collapsibility were observed between two groups. In the multivariate linear regression analysis with total flight time as an independent continuous variable for fighter pilots, TAPSE was positively correlated with total flight time. The experience of fighter pilots who were exposed to high-G acceleration forces and anti-G maneuvers did not cause cardiac structural changes, but the exposure might be associated with right heart function changes.

The Utility of Echocardiography in Estimating Fluid Responsiveness.

Assessing the volume status in critically ill patients is the key to maintain the stability of the hemodynamics; however, it can be challenging to view the complexity of cases and the diversity of shock etiology. Multiple noninvasive means have been used to study the effectiveness of volume resuscitation, but none of them have been used as gold standard. We aim to illustrate the most used techniques: left ventricular outflow tract velocity time integral versus inferior vena cava compressibility index, and highlight their limitations and strengths. These tools are both operator-dependent and might be affected by several factors including ventilator settings.

Diagnostic accuracy of left ventricular outflow tract velocity time integral versus inferior vena cava collapsibility index in predicting post-induction hypotension during general anesthesia: an observational study.

Point of care ultrasound (POCUS) is being explored for dynamic measurements like inferior vena cava collapsibility index (IVC-CI) and left ventricular outflow tract velocity time integral (LVOT-VTI) to guide anesthesiologists in predicting fluid responsiveness in the preoperative period and in treating post-induction hypotension (PIH) with varying accuracy. In this prospective, observational study on included 100 adult patients undergoing elective surgery under general anesthesia, the LVOT-VTI and IVC-CI measurements were performed in the preoperative room 15 minutes prior to surgery, and PIH was measured for 20 minutes in the post-induction period. The incidence of PIH was 24%. The area under the curve, sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of the two techniques at 95% confidence interval was 0.613, 30.4%, 93.3%, 58.3%, 81.4%, 73.6% for IVC-CI and 0.853, 83.3%, 80.3%, 57.1%, 93.8%, 77.4% for LVOT-VTI, respectively. In multivariate analysis, the cutoff value for IVC-CI was >51.5 and for LVOT-VTI it was ≤17.45 for predicting PIH with odd ratio [OR] of 8.491 (P=0.025) for IVCCI and OR of 17.427 (P<0.001) for LVOT. LVOT-VTI assessment was possible in all the patients, while 10% of patients were having poor window for IVC measurements. We recommend the use of POCUS using LVOT-VTI or IVC-CI to predict PIH, to decrease the morbidity of patients undergoing surgery. Out of these, we recommend LVOT-VTI measurements as it has showed a better diagnostic accuracy (77.4%) with no failure rate.

Unique Constellation of Vascular Anomalies in a Female Cadaver: IVC, Renal Vein, and Left Colic Artery Variation

Embryological development of the vascular system consists of growth and regression of developing vessels, often resulting in numerous variations. This cadaveric case report describes an individual with a duplicated inferior vena cava accompanied by multiple left accessory renal veins and a superior mesenteric artery-derived left colic artery. These structures may present clinical concerns when physicians are unaware of their presence during even routine surgeries. The 74-year-old female donor was dissected as part of a medical gross anatomy elective course. Anatomy was photographed and measurements were taken. Dissection revealed a duplicated inferior vena cava with a confluence between the right and left inferior venae cavae, known as the preaortic trunk. The left gonadal vein drained directly into the left inferior vena cava, inferior to the vena cava’s junction with the left renal vein. The multiple accessory left renal veins drained into the left inferior vena cava at the level of the primary left renal vein. All three anomalies examined in this donor have the potential to create complications during surgery. Promoting familiarity amongst physicians, particularly radiologists and surgeons, with vascular anomalies can aid in their ability to assess patients and provide better care.

Quantification of whole-organ individual and bilateral renal metabolic rate of oxygen.

Renal metabolic rate of oxygen (rMRO2 ) is a potentially important biomarker of kidney function. The key parameters for rMRO2 quantification include blood flow rate (BFR) and venous oxygen saturation (SvO2 ) in a draining vessel. Previous approaches to quantify renal metabolism have focused on the single organ. Here, both kidneys are considered as one unit to quantify bilateral rMRO2 . A pulse sequence to facilitate bilateral rMRO2 quantification is introduced. To quantify bilateral rMRO2 , measurements of BFR and SvO2 are made along the inferior vena cava (IVC) at suprarenal and infrarenal locations. From the continuity equation, these four parameters can be related to derive an expression for bilateral rMRO2 . The recently reported K-MOTIVE pulse sequence was implemented at four locations: left kidney, right kidney, suprarenal IVC, and infrarenal IVC. A dual-band variant of K-MOTIVE (db-K-MOTIVE) was developed by incorporating simultaneous-multi-slice imaging principles. The sequence simultaneously measures BFR and SvO2 at suprarenal and infrarenal locations in a single pass of 21 s, yielding bilateral rMRO2 . SvO2 and BFR are higher in suprarenal versus infrarenal IVC, and the renal veins are highly oxygenated (SvO2 >90%). Bilateral rMRO2 quantified in 10 healthy subjects (8 M, 30 ± 8 y) was found to be 291 ± 247 and 349 ± 300 (μmolO2 /min)/100 g, derived from K-MOTIVE and db-K-MOTIVE, respectively. In comparison, total rMRO2 from combining left and right was 329 ± 273 (μmolO2 /min)/100 g. The present work demonstrates that bilateral rMRO2 quantification is feasible with fair reproducibility and physiological plausibility. The indirect method is a promising approach to compute bilateral rMRO2 when individual rMRO2 quantification is difficult.

Technical Feasibility and Clinical Efficacy of Iliac Vein Stent Placement in Adolescents and Young Adults with May-Thurner Syndrome.

To report technical feasibility and clinical efficacy of iliac vein stent placement in adolescent patients with May-Thurner Syndrome (MTS). Single-institution retrospective review of the medical record between 2014 and 2021 found 63 symptomatic patients (F = 40/63; mean age 16.1years, 12-20years) who underwent left common iliac vein (LCIV) stent placement for treatment of LCIV compression from an overriding right common iliac artery, or equivalent (n = 1, left IVC). 32/63 (50.7%) patients presented with non-thrombotic iliac vein lesions (NIVL). 31/63 (49.2%) patients presented with deep vein thrombosis of the lower extremity and required catheter-directed thrombolysis after stent placement (tMTS). Outcomes include technically successful stent placement with resolution of anatomic compression and symptom improvement. Stent patency was monitored with Kaplan-Meier analysis at 3, 6, 12, 24, and 36months. Anticoagulation and antiplatelet (AC/AP) regimens were reported. Technical success rate was 98.4%. 74 bare-metal self-expanding stents were placed in 63 patients. Primary patency at 12, and 24-months was 93.5%, and 88.9% for the NIVL group and 84.4% and 84.4% for the tMTS group for the same period. Overall patency for the same time intervals was 100%, and 95.4% for the NIVL group and 96.9%, and 96.9% for the tMTS group. Procedural complication rate was 3.2% (2/63) with no thrombolysis-related bleeding complications. Clinical success was achieved in 30/32 (93.8%) and 29/31 (93.5%) patients with tMTS and NIVL groups, respectively. CIV stent placement in the setting of tMTS and NIVL is technically feasible and clinically efficacious in young patients with excellent patency rates and a favorable safety profile.

Abstract 15979: En Bloc Heart-Lung Transplantation and Vascular Reconstruction With Native Tissue in a Patient With Situs Inversus Totalis

Case: A 62-year-old male with primary ciliary dyskinesia, bronchiectasis, dextrocardia, ccTGA, VSD, ASD, and severe ventricular dysfunction was listed for HLTx. Suitable organs became available from a 21-year-old male donor after brain death. The right sided aorta, persistent left superior vena cava (LSVC), RIJ, and LCFV were cannulated for CPB. The bloc was procured in the typical fashion along with the donor’s pericardium and intact innominate vein. During the recipient cardiectomy, the LSVC was transected proximally, and right atrial (RA) tissue preserved in continuity with the left inferior vena cava (LIVC). To achieve situs solitus positioning of the mediastinum, a pericardial sling was created by plicating the right pericardium to the diaphragmatic pericardium, and the left pericardium was augmented with excess donor pericardial tissue to create a neo-pericardium in the left chest. The recipient’s RA tissue was used to extend the LIVC by forming a cavoatrial conduit and anastomosed to the donor RA, which required a slightly counterclockwise rotation of the cardiac axis and facilitated positioning the left phrenic nerve posterior to the apex. The tracheal and aortic anastomoses were performed in the typical fashion. The donor innominate vein was of sufficient caliber and length to complete the anastomosis to the recipient LSVC and the donor RIJ was ligated. Discussion: HLTx remains the only definitive therapy for patients with combined end-stage cardiopulmonary disease. The leading indication for HLTx is congenital heart disease. Accordingly, centers performing HLTx must be experienced in complex vascular reconstructions and concomitant procedures to address a broad spectrum of anatomical variants. With thoughtful pre-operative planning, close communication with the procurement team, and surgical experience, these procedures may be performed without the use of synthetic materials that predispose to infectious and thromboembolic complications.

Abstract 14776: Myopericarditis Mimicking Myocardial Infarction With Non-Obstructive Coronary Arteries

This is a case of a 76-year-old female with a past medical history of recurrent paroxysmal symptomatic supraventricular tachycardia (SVT), atherosclerotic heart disease, mild aortic and mitral valve regurgitation, mild-moderate tricuspid regurgitation, right bundle branch block, hypothyroidism and bronchiectasis who presented to her dermatology appointment with palpitations and dizziness. She visited the cardiologist's office and was found to have SVT on electrocardiogram which did not terminate with Valsalva maneuvers. She arrived at the emergency department with chest pain and converted to sinus rhythm after 6 mg of intravenous adenosine was administered. Her troponin peaked to 0.21 and she was admitted with concerns for non-ST segment elevation myocardial infarction. Transthoracic echocardiogram showed left ventricular ejection fractions of 61 percent with no wall motion abnormalities and left atrial and inferior vena cava dilation. She underwent left heart catheterization which only showed mild calcification and minimal luminal irregularities of the left anterior descending artery. Cardiac MRI showed myopericarditis and she was discharged with 0.6 mg of colchicine twice daily with plans for outpatient follow up. Discussion Patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) are discovered to have myocarditis on cardiac MRI 25-30% of time. However, this case uniquely demonstrates myopericarditis as the cause for MINOCA which may not have been previously specified. In addition, it is important to emphasize the utility of Cardiac MRI as a non-invasive modality to diagnose MINOCA “mimics”, especially in the female population.

How I treat nutcracker syndrome

Anatomic compression of the left renal vein in the angle between the aorta and superior mesenteric artery may be asymptomatic or may result in symptoms, including flank pain, hematuria, or pelvic pain and/or congestion. Patients can be referred to a vascular surgeon due to symptoms and/or radiologic findings. Because symptoms of nutcracker syndrome can be vague and/or nondiagnostic, careful evaluation, assessment, and counseling with patients are required before undertaking intervention, which is often an open surgical procedure. The definitive diagnosis is ideally confirmed with diagnostic venography, including pressure measurements from the left renal vein and inferior vena cava. The optimal treatment includes open decompression of the left renal vein with renal vein transposition or gonadal vein transposition, with or without concomitant management of pelvic varicosities if symptomatic. Because most patients with nutcracker syndrome are young, long-term follow-up with scheduled ultrasound examinations should be maintained.

CFD Study of the Effect of the Angle Pattern on Iliac Vein Compression Syndrome.

Iliac vein compression syndrome (IVCS, or May-Thurner syndrome) occurs due to the compression of the left common iliac vein between the lumbar spine and right common iliac artery. Because most patients with compression are asymptomatic, the syndrome is difficult to diagnose based on the degree of anatomical compression. In this study, we investigated how the tilt angle of the left common iliac vein affects the flow patterns in the compressed blood vessel using three-dimensional computational fluid dynamic (CFD) simulations to determine the flow fields generated after compression sites. A patient-specific iliac venous CFD model was created to verify the boundary conditions and hemodynamic parameter set in this study. Thirty-one patient-specific CFD models with various iliac venous angles were developed using computed tomography (CT) angiograms. The angles between the right or left common iliac vein and inferior vena cava at the confluence level of the common iliac vein were defined as α1 and α2. Flow fields and vortex locations after compression were calculated and compared according to the tilt angle of the veins. Our results showed that α2 affected the incidence of flow field disturbance. At α2 angles greater than 60 degrees, the incidence rate of blood flow disturbance was 90%. In addition, when α2 and α1 + α2 angles were used as indicators, significant differences in tilt angle were found between veins with laminar, transitional, and turbulent flow (p < 0.05). Using this mathematical simulation, we concluded that the tilt angle of the left common iliac vein can be used as an auxiliary indicator to determine IVCS and its severity, and as a reference for clinical decision making.

Congenital venous anomalies associated with retrocaval ureter: evaluation using computed tomography.

Retrocaval ureter is a rare congenital anomaly resulting from anomalous development of inferior vena cava (IVC) and not from anomalous of the ureter. The anomaly always occurs on the right side due to regression of right supracardinal vein and persistence of right posterior cardinal vein. Retrocaval ureter tends to be associated with various vena cava anomalies because of the embryogenesis. We aimed to identify the prevalence of associated congenital venous anomalies (CVA) resulting from cardinal vein development in adults with retrocaval ureter using computed tomography (CT) images. The study included 22 adults with retrocaval ureter. We evaluated CT findings and determined the incidence of associated CVA using thin slice data sets from CT scanner with 64 or more detectors. We compared the prevalence of CVA in the retrocaval ureter group (mean age: 57 ± 19 years) and in the control group of 6189 adults with normal ureter (mean age: 66 ± 14 years). In the retrocaval ureter group, 4 (18.2%) adults had CVA including double IVC, right double IVC, preisthmic IVC with horseshoe kidney, and preaortic iliac confluence. One of 2 adults with preaortic iliac confluence had right double right IVC. In the control group, 49 (0.79%) adults had CVA including 37 double IVC, 11 left IVC, and 1 IVC interruption azygos continuation. Fifteen horseshow kidneys were found. The prevalence of associated CVA in the retrocaval ureter group was higher than that in the control group (p < 0.001). Retrocaval ureter is frequently associated with CVA. Various CVA with retrocaval ureter could happen because of abnormal development of not only the right posterior or supra cardinal vein but also other cardinal veins.

Thrombus formation in the suprahepatic inferior vena cava after microwave ablation in patients with hepatic metastasis: a case report

BackgroundMicrowave ablation (MWA) via ultrasound guidance is an important tool in the treatment of liver metastases. The most common postoperative complications are abdominal hemorrhage and bile leakage, whereas thrombosis in the suprahepatic inferior vena cava (IVC) is very rare, and clinical management is very difficult when the head end of the thrombus reaches the right atrium.Case presentationThis is a case report of a 52-year-old man with hepatic metastasis 21 months after radical resection of rectal cancer. After chemotherapy combined with targeted therapy, metastasis in segment IV (S4) of the liver was treated with microwave ablation. Two months after treatment, the hepatic metastasis in S4 showed a microwave ablation zone on MRI.Enhanced MRI showed venous thrombosis located in the left hepatic vein and IVC, and the head of the thrombus reached the right atrium. After two weeks of anticoagulation and thrombolytic treatment, the follow-up MRI showed that the venous thrombus had nearly disappeared.ConclusionWhen liver metastases are close to the hepatic vein, clinicians should pay attention to the occurrence of hepatic vein and IVC thrombosis following MWA; through early diagnosis and anticoagulation, pulmonary thromboembolism (PTE) can be minimized.