Vein Drainage Research Articles

A rare variations of the cephalic vein drainage: two cases report.

Throughout the years, anatomic studies have demonstrated numerous variations in the course of the cephalic vein (CV). There are, however, very rare cases of uncommon formation, course or termination of the vein to which our attention should be drawn. During a routine dissections conducted in the Department of Anatomy and Neurobiology, in two formalin-fixed cadavers, the very rare anatomical variants were found. In 80 year-old Caucasian female the right cephalic vein, after crossing the clavipectoral triangle, ascended anterior and superior to the clavicle and drained into the lateral branch of the right external jugular vein, which in turn opened to the right subclavian vein. In the second case, the dissection of 83 year-old Caucasian male cadaver revealed that after passing through the deltopectoral groove, the left cephalic vein run between clavicle and subclavius muscle to terminate in the left subclavian vein. Understanding of the topography, morphology and anatomical variations of the cephalic vein is important not only for the anatomists but for the clinicians and nurses as well. Such knowledge can prevent multiple complications during many invasive procedures including implantation of Cardiac Implantable Electronic Devices, central venous access, arteriovenous fistula creation or even iatrogenic injuries during clavicle or glenohumeral joint surgery.

Evaluation of inferior mesenteric vein drainage patterns in the Turkish population: A multidetector computed tomography study

Background/Aim: The inferior mesenteric vein (IMV) plays a crucial role in the venous system as it joins the superior mesenteric vein (SMV) and splenic vein to form the portal vein. The widespread adoption of multidetector computed tomography (MDCT) has greatly enhanced our ability to assess abdominal vascular structures. This study aimed to investigate the IMV drainage patterns in a Turkish population using MDCT. Methods: This descriptive, single-center, retrospective study included patients who had undergone abdominal computed tomography (CT) in the portal phase at our hospital for various clinical indications. Excluded from the study were patients who did not undergo imaging in the portal venous phase, those with incomplete evaluation of all IMV segments, and individuals who had undergone pancreaticoduodenal or intestinal surgery for any reason. We retrospectively analyzed a total of 877 contrast-enhanced MDCT examinations performed at our hospital between March 2022 and March 2023. Patients were classified based on their IMV drainage patterns into the following categories: type 1 (drainage into the splenic vein), type 2 (drainage into the SMV), type 3 (drainage at the junction level), type 4 (drainage into the branches of the SMV), and type 5 (patients in whom IMV assessment was not possible). Results: The mean age of the patients was 48.7 years (range: 24–92 years), with 449 (51.2%) being male and 428 (48.8%) female. The distribution of patients according to IMV drainage patterns was as follows: type 1, n=379 (43.2%); type 2, n=398 (45.4%); type 3, n=71 (8.1%); type 4, n=15 (1.7%); and type 5, n=14 (1.6%). Conclusion: Our study findings indicate that in the Turkish population, the IMV predominantly drains into the SMV before joining the splenic vein. This disparity from certain studies in the literature underscores the variability in IMV drainage patterns, emphasizing the importance of individualized patient evaluation in this regard.

FRI196 Non-Hemorrhagic Adrenal Infarction in Pregnancy with Tuberous Sclerosis

Abstract Disclosure: A. Mahaldar: None. H. Al Jumaili: None. S.R. Campbell: None. M.Z. Baker: None. Background: Non hemorrhagic adrenal infarction is a rare diagnosis in pregnancy with less than 20 cases reported in literature so far. No cases have been reported in patients with tuberous sclerosis. Most patients present with abdominal pain. Clinical Case: 29 year old woman G2P1 presented at 35 weeks gestation with right upper quadrant pain. She reported two episodes of dizziness in first trimester but otherwise had an uneventful pregnancy prior to presentation. First pregnancy was uncomplicated. Past medical history included asymptomatic tuberous sclerosis. No previous history of blood clots. Physical examination revealed a distended abdomen appropriate for gestational age and right upper quadrant tenderness to palpation. Initial laboratory data was unremarkable except for leukocytosis with WBC 16.6 k/mm3 (4-11 k/mm3). Normal electrolytes and liver function tests. Abdominal ultrasound revealed cholelithiasis without evidence of acute cholecystitis and unremarkable renal findings. CT abdomen pelvis with contrast showed thickening with surrounding stranding of right adrenal gland suggesting acute adrenal infarction and multiple pancreatic cysts. 8 am cortisol was 4.9 mcg/dl (4.1-16.6 mcg/dl) and ACTH was 23 pg/ml (7.2-63.3 pg/ml). Patient had received 2 doses of betamethasone due to concern for preterm delivery at 48 hours and 36 hours prior to this blood draw. Hypercoagulable panel was sent prior to starting enoxaparin. Elevated Factor VIII >150% (50 to 150%) was noted as expected in pregnancy. Lupus anticoagulant was weakly positive with LA sensitive PTT 50.1 (0 to 51.9 sec). Anticardiolipin antibody and beta 2 glycoprotein antibody were normal. Patient was treated with hydrocortisone 15 mg by mouth daily and full dose enoxaparin for anticoagulation. At one month follow up 8 am cortisol was 24 mcg/dl. Hydrocortisone replacement was discontinued. Labor was uncomplicated with vaginal delivery at 38 weeks gestation. Day 1 postpartum at 7:30 AM cortisol was 20.94 mcg/dl. Patient was discharged home in a stable condition with continued anticoagulation with enoxaparin and no further hydrocortisone treatment. Conclusion: We present a case of non hemorrhagic adrenal infarction in a pregnant patient with tuberous sclerosis. Adrenal infarction without hemorrhage is rare. Anatomy of adrenal gland makes it prone to microvascular thrombosis and infarction in a thrombotic state because of single draining vein for venous drainage. Pregnancy as a hypercoagulable state has been previously associated with non hemorrhagic adrenal infarction in few case reports. Whether tuberous sclerosis played any role in our patient’s pathogenesis remains unclear as there are no data or case reports linking the two. In conclusion, the diagnosis of non hemorrhagic adrenal infarction needs to be considered in hypercoagulable or pregnant patients presenting with abdominal pain. Presentation: Friday, June 16, 2023

Standardized Methodology for Duplex Ultrasound Examination of Arteriovenous Access for Hemodialysis: A Proposal of the French Society of Vascular Medicine and the French-Speaking Society of Vascular Access.

Duplex ultrasound (DUS) is an essential tool for characterizing and monitoring arteriovenous (AV) access for hemodialysis. The aim of the work described here, requested by the French Society of Vascular Medicine in collaboration with the French-Speaking Vascular Access Society, is to propose a standardized methodology for performing and documenting DUS, taking into account the variety of AV access techniques and the problems routinely encountered. A steering committee reviewed the literature and selected the relevant references. A draft was prepared, and all items with missing or conflicting data were submitted to a Delphi consensus. The final document was discussed and approved by all participants. The principles of DUS evaluation of AV access consist of examination of the afferent artery, the anastomosis and the entire venous drainage system. DUS uses B-mode ultrasound, color flow, pulsed wave and power Doppler analysis. DUS can be used in a variety of clinical situations, which can directly influence the methodology of the examination and the interpretation of the results. Blood flow should be assessed as it correlates with the risk of thrombosis. The measurement should be adapted to the different anatomical and hemodynamic conditions encountered. Characterization of stenosis should take into account the residual diameter of the drainage vein and its hemodynamic consequences. Other complications can be assessed with a standardized DUS examination. When performed according to a rigorous methodology, DUS of the AV access allows a comprehensive assessment of its functionality and eliminates the need for further invasive diagnostic procedures.

Quantitative anatomy of the large variant right hepatic vein: A systematic three-dimensional analysis.

Anatomical variations of the right hepatic vein, especially large variant right hepatic veins (≥5 mm), have important clinical implications in liver transplantation and resection. This study aimed to evaluate anatomical variations of the right hepatic vein using quantitative three-dimensional visualization analysis. Computed tomography images of 650 patients were retrospectively analyzed, and three-dimensional visualization was applied using the derived data to analyze large variant right hepatic veins. The proportion of the large variant right hepatic vein was 16.92% (110/650). According to the location and number of the variant right hepatic veins, the configuration of the right hepatic venous system was divided into seven subtypes. The length of the retrohepatic inferior vena cava had a positive correlation with the diameter of the right hepatic vein (rs = 0.266, p = 0.001) and the variant right hepatic veins (rs = 0.211, p = 0.027). The diameter of the right hepatic vein was positively correlated with that of the middle hepatic vein (rs = 0.361, p < 0.001), while it was inversely correlated with that of the variant right hepatic veins (rs = -0.267, p = 0.005). The right hepatic vein diameter was positively correlated with the drainage volume (rs = 0.489, p < 0.001), while the correlation with the variant right hepatic veins drainage volume was negative (rs = -0.460, p < 0.001). The number of the variant right hepatic veins and their relative diameters were positively correlated (p < 0.001). The volume and percentage of the drainage area of the right hepatic vein decreased significantly as the number of the variant right hepatic vein increased (p < 0.001). The findings of this study concerning the variations of the hepatic venous system may be useful for the surgical planning of liver resection or transplantation.

Isolated persistent left superior vena cava associated with anomalous left hepatic vein drainage into the right atrium accidentally discovered after sternotomy.

Isolated persistent left superior vena cava associated with anomalous left hepatic vein drainage into the right atrium accidentally discovered after sternotomy.

Two Neighboring Spinal Dural Arteriovenous Fistulas with Multiple Bridging Veins Drainage

Two neighboring spinal dural arteriovenous fistulas (SDAVFs) with multiple bridging veins drainage are extremely rare. Here, we report a 55-year-old man with 2 neighboring SDAVFs at the levels of T4-T5 supplied by the right T5 intercostal artery (common stem of T4 and T5 arteries) with multiple draining veins. Intraoperatively, 3 draining bridging veins between T4 and T5 nerve roots were identified and resected successfully. This case demonstrated the complex microscopic angioarchitecture features of 2 neighboring SDAVFs with multiple draining veins. Although these complex SDAVFs are extremely rare, the clinicians should be aware of the possibility of 2 neighboring SDAVFs.

Sinus node dysfunction during transcatheter assessment and stent correction of sinus venosus atrial septal defects.

Covered stent correction of a superior sinus venosus atrial septal defect is increasingly performed as an alternative to surgical repair.While sinus node dysfunction requiring pacemaker implantation may be required after surgical repair, this has not been previously reported after covered stent implantation. We reviewed the experience in two interventional centers.Balloon inflation in the superior vena cava was used to confirm the anomalous pulmonary vein drainage would be unobstructed after stent implantation. During balloon testing in 62 consecutive patients, we assessed gradients across the pulmonary vein to left atrium while monitoring the rhythm. We observed the outcomes after covered stent correction in 51 patients.In a single patient, significant bradycardia and pauses developed on repeat balloon testing and the procedure was abandoned without stent implantation. In another patient, there was no sign of sinus node dysfunction during balloon testing but several hours after stent implantation, the patient became symptomatic from sinus bradycardia and pauses and had a pacemaker implanted 3 days later. Over a year later there are some signs of improvement in sinus node function.While sinus node dysfunction has not been described previously during balloon testing or after stent implantation, this report demonstrates for the first time that it may occur. Larger registries are therefore required to monitor for this uncommon complication.

Hairball-Like Migration of "Onyx Threads" into the Draining Vein during Transarterial Embolization of a Dural Arteriovenous Fistula: A Case Report and Experimental Validation.

Transarterial embolization using Onyx is a well-established treatment for dural arteriovenous fistulas (DAVFs). However, complications can arise when Onyx migrates into the venous side, impairing the draining veins. We encountered a case where Onyx, injected through the arterial side, strayed into the jugular vein, forming a hairball-like structure. Our study aimed to investigate the underlying mechanism of this unusual phenomenon. We postulated that Onyx precipitates into thread-like shapes when passing through extremely narrow openings. To test this, we extruded Onyx from a syringe through a 27-gauge needle into a silicone tube with flowing water. By varying the flow speed, we observed the hardening behavior of Onyx. Under slow flow, the extruded Onyx quickly solidified at the needle tip, forming a round mass. Conversely, high-speed flow resulted in Onyx being dispersed as small pieces. We successfully replicated the formation of "Onyx threads" under continuous slow flow conditions, similar to our case. This phenomenon occurs when Onyx unexpectedly migrates to the draining vein through a tiny opening during transarterial embolization for arteriovenous shunt diseases. Early recognition and appropriate measures are necessary to prevent occlusive complications in the draining veins and the pulmonary system.

Budd-Chiari Syndrome: A Rare Complication of Hepatic Hydatid Cyst

Budd-Chiari syndrome is a rare disease characterized by a defect in hepatic venous drainage. It can be primary, occurring due to venous thrombosis, or secondary, caused by compression or invasion of the hepatic drainage veins. Symptoms can be acute, chronic, or even asymptomatic. Diagnosis is based on imaging tests that show hepatic vein obstruction, collateral circulation, and morphological changes in the liver. Treatment aims to identify and treat the underlying disease.We report a case of a patient with Budd-Chiari syndrome secondary to a liver hydatid cyst to highlight the radiological aspects of this pathology.

Neuronavigation-assisted microsurgical clipping of pericallosal aneurysms: A single-center retrospective study

Surgical clipping of pericallosal artery aneurysm is technically challenging since it is fragile and tends to rupture accidentally during the operation. This study was aimed to evaluate the efficacy and safety of MRI-neuronavigation-assisted microsurgery for pericallosal artery aneurysm clipping. Forty patients diagnosed with pericallosal artery aneurysms who underwent craniotomy clipping were enrolled. Among these patients, 18 cases accepted routine surgical approaches, while another 22 cases accepted MRI-neuronavigation-assisted microsurgery. Design of craniotomy, operation pathway, operation duration, intraoperative cerebral protection and superior drainage vein protection were analyzed retrospectively. All the 40 cases underwent aneurysm clipping by pre-coronal inter-hemispheric approach, and all aneurysms were clipped completely confirmed by postoperative CTA or DSA. During the operations, MRI-neuronavigation provided precise spatial configuration of pericallosal artery aneurysms, and allowed accurate and real-time identification for the adjacent arteries and brain structures, and no aneurysms ruptured accidentally during the operations. Functional cortex and draining veins were protected well. Compared with routine surgical approaches, the MRI-neuronavigation-assisted microsurgery showed less operation duration, few adverse events induced by accurate location for aneurysm and less invasion to draining veins. Therefore, MRI-neuronavigation-assisted microsurgery could precisely locate the pericallosal artery aneurysm, optimize surgical approaches, and help to cerebral protection. It is expected to reduce the surgical risk and improve the precision and security, can be regarded as an effective technology in the clipping of pericallosal artery aneurysms.

High aldosterone levels in the renal capsular vein from the left aldosterone-producing adenoma on adrenal venous sampling.

A 42-year-old female patient was referred to our hospital with hypertension and hypokalemia and was diagnosed with primary aldosteronism. Dynamic contrast-enhanced computed tomography images revealed a 13-mm nodule on the lateral segment of the left adrenal gland and a fine venous connection between the nodule and the prominent renal capsular vein running nearby. The venograms in the left lateral tributary with a microcatheter confirmed alternative drainage to the left renal capsular vein during adrenal venous sampling, and the left renal capsular vein sampling was added. The patient was diagnosed with a left aldosterone-producing adenoma (APA) using the lateralization index (48.3) and a higher plasma aldosterone concentration (PAC) of the left lateral tributary (66 700 pg/mL) than other tributary samples after adrenocorticotropic hormone stimulation. Furthermore, markedly higher PAC (224 000 pg/mL) was observed in the left renal capsular vein blood than in the left adrenal central vein (45 000 pg/mL) and tributaries, confirming the diagnosis. Laparoscopic left partial adrenalectomy and following histopathological analysis revealed a CYP11B2-positive adrenocortical adenoma. Complete clinical and biochemical success for primary aldosteronism was achieved after 6 months. Direct evidence of APA blood venous drainage into the renal capsular vein has been demonstrated. Sampling from an alternative drainage pathway could be beneficial for APA diagnosis if such APA blood drainage is assumed. Aldosterone-producing adenomas may drain blood into an alternative pathway but for the adrenal vein. The presence of alternative venous drainage could be assumed by contrast-enhanced computed tomography or venogram during adrenal venous sampling. Sampling in the alternative drainage veins and demonstrating elevated aldosterone levels could help in diagnosing aldosterone-producing adenoma.

Four-dimensional imaging of umbilical-vein-to-right-atrium shunt in fetus with Type-I Abernethy malformation.

Videoclip S1: The four-chamber view showing dilated right atrium and significant herniation of the RFOA into the left atrium resulting in stretching of the primum septum resembling an ostium primum atrial septal defect. Videoclip S2: Four-chamber grayscale and color Doppler showing vigorous and bidirectional blood flow across the foramen ovale and reduced mitral inflow. Videoclip S3: Grayscale and color Doppler sweep from fetal upper abdomen to four-chamber view showing the umbilical vein draining directly into the right atrium. Videoclip S4: Sagittal color Doppler imaging of the fetal abdomen showing the anomalous extra-hepatic course of the umbilical vein draining directly into the right atrium. Videoclip S5: Axial four-chamber 4D STIC HD-live color silhouette volume rendering showing the extra-hepatic course of umbilical vein draining into the right atrium (hand symbol). Videoclips S6 and S7: Sagittal 4D STIC HD-live color silhouette volume rendering of the fetal abdomen showing the extra-hepatic course of the umbilical vein draining into the right atrium. The ductus venosus and intrahepatic portal venous system (right and left portal veins) were absent. Videoclip S8: Axial color Doppler examination of the fetal abdomen showing compensated liver perfusion by increased hepatic artery blood flow and end to side extrahepatic drainage of main portal vein to inferior vena cava. Videoclip S9: Oblique sagittal 4D STIC HD-live color silhouette volume rendering of the fetal abdomen showing the increased hepatic artery blood flow (hand symbol). Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Clinical features, treatment strategies and outcomes of craniocervical junction arteriovenous fistulas: a cohort study of 193 patients

BackgroundCraniocervical junction (CCJ) arteriovenous fistulas (AVFs) are rare. The current treatment strategies for AVFs with different angioarchitecture need to be clarified. The present study aimed to analyse the correlation between...

Value of fat-suppressed T2-weighted imaging for predicting short-term pain relief after sclerotherapy for venous malformations in the extremities

PurposeThis study aimed to evaluate the value of fat-suppressed T2-weighted imaging (FS-T2WI) for predicting short-term pain relief after polidocanol sclerotherapy for painful venous malformations (VMs) in the extremities.Materials and methodsThis retrospective study included patients with painful VMs in the extremities between October 2014 and September 2021, had their first sclerotherapy without history of surgical therapy, and underwent magnetic resonance imaging before sclerotherapy. Pain relief was assessed 2 months after 3% polidocanol sclerotherapy and was categorized as follows: progression, no change, partial relief, or free of pain. The associations between pain relief and imaging features on FS-T2WI were analyzed.ResultsThe study included 51 patients. The no change, partial relief, and free of pain groups included 6 (11.8%), 25 (49.0%), and 20 (39.2%) patients, respectively. No patient experienced progressive pain. The lesion diameter was ≤ 50 mm in 13 (65.0%) patients in the free of pain group, whereas it was > 50 mm in all patients in the no change group (p = 0.019). The lesions showed well-defined margin in 15 (75.0%) patients in the free of pain group, whereas they showed ill-defined margin in 5 (83.3%) patients in the no change group (p = 0.034). The most common morphological type was cavitary in the free of pain group (14 [70.0%] patients), whereas there was no patient with cavitary type lesion in the no change group (p = 0.003). Drainage vein was demonstrated in 6 (100%), 22 (88.0%), and 11 (55.0%) patients in the no change, partial relief, and free of pain group, respectively (p = 0.011).ConclusionA lesion size of 50 mm or less, a well-defined margin, a cavitary type, and no drainage vein on FS-T2WI were significant features for predicting short-term pain relief after polidocanol sclerotherapy for painful VMs in the extremities.

Partial anomalous venous connection with intrapulmonary dual drainage: Transcatheter treatment of a rare entity.

Partial anomalous pulmonary venous return (PAPVR) is a rare congenital condition, and dual-drainage connection PAPVR to the left atrium has been reported in a few cases in the literature; in which cases, percutaneous catheterization was successfully used in lieu of surgery. We, hereby, describe a 7-month-old boy with a functional single-ventricle physiology with dual drainage of the left upper pulmonary vein to the left atrium and the innominate vein. Appropriate recognition of this entity allowed safe occlusion of the anomalous draining vein.

A rare case of the combination of total abnormal pulmonary vein drainage with congenital lung lymphangiectasia

The article describes a clinical report of a combination of congenital heart disease due to total anomalous pulmonary venous drainage into the right atrium with congenital lung disease — lymphoangiectasia in a newborn infant. The role of extracardiac pathology on the course and outcome of cardiac surgery and the complexity of early diagnosis of a rare lung pathology are presented

Vortex Veins in Eyes With Pachychoroid Spectrum Disorders Evaluated by the Adjusted Reverse 3-Dimensional Projection Model

To compare the distribution of vortex vein ampulla (VVA) between pachychoroid spectrum disorder (PSD) and controls. A single-center, case-control study. This study included 75 PSD, 35 fellow, and 65 control eyes. We quantified VVA distribution using a 3-dimensional reverse projection model corrected for image distortion. We investigated the distribution of major drainage veins (MDV), in which macular Haller's vessels directly influx. The mean distances from the optic disc to VVAs and the mean angles between VVAs and the fovea-disc line. The PSD group had significantly fewer VVA in infranasal sector (PSD, fellow, control; 1.6±0.6, 1.8±0.6, 1.9±0.6, respectively, P= 0.026). In supralateral sector, for PSD, fellows, and controls, the mean distances from the optic disc to VVAs were 14.1±1.0 mm, 14.1±1.1 mm, and 13.6±1.4 mm, respectively, and were significantly farther in PSD than in controls (P= 0.023). The mean angles between VVAs and the fovea-disc line were 64.8±5.9°, 66.4±6.4°, and 61.7±6.4°, respectively, and were significantly higher in PSD and fellows than in controls (P=0.008). The mean distances from the optic disc to MDV in supratemporal sector were 14.1±1.2 and 13.7±1.2 in eyes whose Haller's vessels extended beyond the fovea-disc line (asymmetry), and those that did not, respectively, with the asymmetric eyes significantly farther (P= 0.016). The VVA position in supralateral sector was farther and higher in PSD than in controls, suggesting that the distribution of VVA may be associated with the development of PSD. Proprietary or commercial disclosure may be found after the references.

A retrospective study of 78 adult tentorial middle line region dural arteriovenous fistulae.

Dural arteriovenous fistulae (DAVF) in the tentorial middle line region are uncommon with specific features and more cognitive disorders than any other region. The purpose of this study is to present clinical characteristics and our experience with endovascular treatment in this specific region. During a 20-year period, 94.9% of patients (74/78) underwent endovascular treatment (36 in galenic, 48.6%) (12 in straight sinus, 16.2%) (26 in torcular, 35.1%). There were 63 males and 15 females with mean age of 50 (50 ± 12) years in total of 78 patients. The clinical presentation, angiographic features, treatment strategy, and clinical outcomes were recorded. Transarterial embolization (TAE) was performed in 89.2% of the 74 patients (66/74), transvenous embolization alone in one patient and mixed approach in seven. Complete obliteration of the fistulas was obtained in 87.5% of the patients (64/74). 71 patients (mean, 56months) had phone, outpatient, or admission follow-up. The digital subtraction angiography (DSA) follow-up period (25/78, 32.1%) was 13.8 (6-21) months. Two of them (2/25, 8%) had fistula recurrences after complete embolization and were embolized again. The phone follow-up period (70/78, 89.7%) was 76.6 (40-92.3) months. Pre-embolization and post-embolization mRS ≥ 2 were in 44 patients (44/78) and 15 (15/71) patients, respectively. DAVF with internal cerebral vein drainage (OR 6.514, 95% Cl 1.201-35.317) and intracranial hemorrhage (OR 17.034, 95% Cl 1.122-258.612) during TAE were the risk factors for predicting poor outcomes (followed up mRS ≥ 2). TAE is the first-line treatment for tentorial middle line region DAVF. When pial feeders' obliteration is difficult to achieve, it should not be forced due to the poor outcomes after intracranial hemorrhage. The cognitive disorders caused by this region were not reversible as reported. It is imperative to enhance the care provided to these patients with cognitive disorders.

Resection of Midbrain Cavernous Malformation Associated With Complicated Draining Veins From Coexistent Developmental Venous Anomalies: 360° Virtual Reality Enhanced Operative Video.

Department of Neurosurgery, Saitama Medical Center, Saitama Medical University, Saitama, Japan Correspondence: Soichi Oya, MD, PhD, Department of Neurosurgery, Saitama Medical Center, Saitama Medical University, 1981 Kamoda, Kawagoe, Saitama350-8550, Japan. Email: [email protected]