Degree of Left Renal Vein Compression Predicts Nutcracker Syndrome

Insights into pelvic venous disorders

Pelvic venous disorders (PeVD), sometimes referred to as pelvic congestion syndrome (PCS), widely impact affected patients-mainly young women's quality of life, causing puzzling, uncomfortable symptoms sometimes requiring months or years to get an explanation, while simply remaining undiagnosed in other cases. Because pelvic pain is a non-specific symptom, an appropriate diagnosis requires a careful patient workup, including a correlation between history and non-invasive imaging. Invasive imaging is frequently required to confirm the diagnosis and plan treatment. Current therapeutic approaches principally rely on minimally invasive techniques delivered through endovascular access. However, while comprehensive descriptive classifications such as the symptoms-varices-pathophysiology (SVP) classification exist, universally accepted guidelines regarding therapy to apply for each SVP category are still lacking. This review strongly focuses on PeVD imaging and discusses available therapeutic approaches with regard to pathophysiological mechanisms. It proposes a new classification scheme assisting clinical decision-making about endovascular management to help standardize the link between imaging findings and treatment.

A systematic review on nutcracker syndrome and proposed diagnostic algorithm

OBJECTIVE

Nutcracker syndrome (NCS) is an increasingly recognized venous compressive disease. Although people with NCS can experience debilitating symptoms, making an accurate diagnosis can often be challenging owing to the broad spectrum of clinical presentations and radiologic findings. In the present systematic review, we assessed the most frequent clinical and radiologic criteria used in establishing a diagnosis of NCS and have proposed a comprehensive framework for clinical decision-making.

METHODS

We performed a systematic review to identify all observational studies or case series conducted within the previous 10 years that had studied patients with a clinical and radiologic diagnosis of NCS. The extracted data included details related to the study design, participant demographics, presenting clinical features, and radiologic criteria. These details were compared between studies and synthesized to establish a comprehensive diagnostic framework that would be applicable to clinical practice.

RESULTS

In the present review, we included 14 studies with a total of 384 patients with NCS. The most common clinical features of NCS were hematuria (69.5%), left flank or abdominal pain (48.4%), pelvic pain (23.1%), and varicocele (15.8%). Computed tomography and ultrasound were the most commonly used imaging modalities, with a threshold for left renal vein stenosis of >80% the most frequently used diagnostic parameter. Eight studies had used venography, with the renocaval pressure gradient the most commonly measured parameter. Two studies had reported using intravascular ultrasound. The findings from our review have shown that a thorough clinical workup of NCS should include critical evaluation of the presenting clinical features and exclusion of alternative diagnoses. All patients should undergo duplex ultrasound with or without the addition of computed tomography or magnetic resonance imaging. Any patient considered for therapeutic intervention should also undergo diagnostic venography with measurement of the renocaval pressure gradient and, if available, intravascular ultrasound with measurement of the left renal vein diameters.

CONCLUSIONS

NCS is a challenging condition in terms of the diagnosis and management both. We have proposed a comprehensive diagnostic framework based on the currently available literature to aid in clinical decision-making.

Nutcracker syndrome, conservative approach: a case report

The nutcracker phenomenon (NCP) refers to the compression of the left renal vein, most commonly between the aorta and the superior mesenteric artery (SMA). Nutcracker syndrome (NCS) should be limited to patients who present with the characteristic clinical signs and symptoms alongside diagnostic imaging of the anatomy associated with the syndrome. We report a case of NCS presenting with painless visible hematuria and left flank pain. Imaging showed a left renal vein stenosis at the origin of the SMA with collateralization. Diagnosis of NCP is made by a variety of imaging techniques; approaches to the treatment of NCS include conservative methods, open surgical, laparoscopic or endovascular techniques. Correlation with symptoms, laboratory results and excluding other causes continues to be important in the workup of NCS. Collaboration with the establishment of an International Consortium database will aid in the understanding of this rare disease.

Coexistence of superior mesenteric artery syndrome and nutcracker phenomenon

Superior mesenteric artery (SMA) syndrome is a rare cause of upper gastrointestinal obstruction. Nutcracker syndrome occurs as the result of external compression of the left renal vein. Although they share a similar pathophysiology, SMA and nutcracker syndrome occurring simultaneously is rare. In this case report, we discuss the pathophysiology and unique computed tomography findings in a 25-year-old female patient diagnosed with SMA syndrome who was also incidentally found to have a coexisting nutcracker phenomenon. Due to similar pathogenesis, radiologists should consider the possibility of coexistence of these rare syndromes in appropriate patients.

The Superior Mesenteric Artery Angle and Abdominal Main Vessel Diameters in Normovolemic Children: For Practical Sonographic Evaluation

BACKGROUND

Knowledge of the normal size of important abdominal vessels is important for determination of hydration status and intravascular volume. Knowing the normal value of superior mesenteric artery (SMA) exit angle from the aorta (SMA angle) is necessary for the diagnosis of clinical pathologies caused by SMA compression.

OBJECTIVES

The aim of this study was to determine the normal SMA angles and normal diameters of the main abdominal vascular structures of pediatric participants on ultrasonography (USG).

METHODS

Between January 2019 and July March 2019, the USG examinations obtained from 210 participants (age range, 1-214 years; mean age, 83.5 [SD, 5.5] months; females 51%, males 49%) with normal abdominal examinations were prospectively evaluated. The participants were divided into 5 groups according to age. Body mass index values of the participants were kept equal.

RESULTS

The diameters of the abdominal vascular structures increased with age, and the statistical differences among the age groups were significant. In all groups, no statistically significant difference was observed between sexes (P > 0.05). The SMA angle was between 17° and 58° (mean, 37.8° [SD, 8.5°]). A statistically significant difference was observed between the age groups in terms of SMA angle (P < 0.05). No statistically difference was found between sexes (P > 0.58-0.912).

CONCLUSIONS

In our study, we think that the measurements obtained by USG provide normal values of the diameters of the abdominal main vessels and SMA angle. These values can be used as a reference for interpreting hydration status, vascular diameter assessment, and SMA compression syndromes.

Nutcracker syndrome: diagnosis and therapy

Nutcracker syndrome (NCS) is an extrinsic compression of the left renal vein (LRV) by the superior mesenteric artery (SMA) anteriorly and aorta posteriorly resulting in renal vascular congestion manifesting as hematuria, proteinuria, orthostatic hypotension, pain, or even renal dysfunction. Long-standing venous compression can encourage collateral drainage pathways through gonadal and pelvic veins, which may explain reported symptom and syndrome overlap with pelvic congestion syndrome. Diagnosis can be challenging and variable, frequently involving a combination of ultrasound Doppler, cross-sectional, and invasive imaging. Often, intravascular pressure measurements are required to prove a renocaval pressure gradient to aid in a definitive diagnosis. Conservative management is appropriate, especially in children, who tend to outgrow the disorder. In the interim, medical management with angiotensin converting enzyme inhibitors (ACEIs) is a useful therapy to manage orthostatic hypotension in the pediatric population. In adults, invasive therapies are more frequently pursued. These are aimed at relieving the extrinsic compression on the LRV. The standard of care is renal vein transposition, with renal autotransplantation reserved for recalcitrant cases. Endovascular stenting is a less invasive option. Laparoscopic placement of an exovascular stent is a newer therapy intended to minimize trauma to the LRV. In this review, we will discuss the clinical manifestations, diagnostic criterion, imaging features, and conservative and surgical therapies for this condition.

Left renal vein compression complicating intragastric balloon insertion

Obesity is a real public health problem and is of growing concern. People are resorting to surgical or endoscopic means to fight against overweight and obesity. In recent years, there has been a marked increase in the use of these means and in particular the insertion of a gastric balloon which seems to present less risk than surgical methods. Renal complications from intragastric balloon placement are extremely rare. We report here the case of compression of the left renal vein revealed by lumbar pain and hematuria in an overweight 39-year-old woman who benefited from the balloon gastric placement one month before symptoms. The scanner made the diagnosis and showed a good evolution after the withdrawal of the balloon.

Value of magnetic resonance imaging indices of left renal vein entrapment in the diagnosis of nutcracker syndrome in children

BACKGROUND

Nutcracker syndrome (NCS) is also known as left renal vein (LRV) compression syndrome. Magnetic resonance imaging (MRI) can better depict the anatomical structure of soft tissues in the area of compression. Diagnosis of NCS using MRI in adults is not uncommon. However, there are few studies on the diagnosis of NCS using MRI in children. Therefore, we conducted this study to evaluate the clinical value of the MRI indices of the LRV in the diagnosis of NCS in children.

METHODS

This study was a single-center retrospective analysis. One hundred seventy-four patients with suspected NCS were enrolled from January 2017 to July 2020. The inclusion criteria for suspected NCS were mainly based on clinical symptoms or signs, laboratory examinations and imaging reports. Other diseases that may cause hematuria and/or proteinuria were excluded. We grouped the patients based on the diagnostic criteria for NCS into a nutcracker group and a control group. The receiver operating characteristic (ROC) curve was constructed for evaluating the value of MRI indices in the diagnosis of NCS.

RESULTS

The majority of NCS patients presented with orthostatic proteinuria (OP) (67.2%), followed by hematuria (55.2%), abdominal pain (19.0%), and left flank pain (15.5%). The areas under the curve (AUCs) for the superior mesenteric artery (SMA) angle, beak sign, and compression ratio (CR) in the diagnosis of NCS were 0.870, 0.895, and 0.878, respectively, and the best cutoff values of the SMA angle and CR were 36.8 and 3.99, respectively. The specificities of SMA angle <36.8°, beak sign, CR >3.99, SMA angle <36.8° and beak sign, SMA angle <36.8° and CR >3.99, and beak sign and CR >3.99 were 82.5%, 93.8%, 93.8%, 97.9%, 95.9% and 97.9%, respectively.

CONCLUSIONS

Children with SMA angles less than 36.8°, beak signs and CR greater than 3.99 should be highly suspected of having NCS. Among these parameters, "beak sign" showed the highest diagnostic accuracy by MRI, and the combination of any two of the above parameters achieved a higher specificity than the single parameters.

The Symptoms-Varices-Pathophysiology classification of pelvic venous disorders: A report of the American Vein & Lymphatic Society International Working Group on Pelvic Venous Disorders

This Practice Guidelines document has been co-published in Phlebology [DOI: 10.1177/0268355521999559] and Journal of Vascular Surgery: Venous and Lymphatic Disorders [DOI: 10.1016/j.jvsv.2020.12.084]. The publications are identical except for minor stylistic and spelling differences in keeping with each journal’s style. The contribution has been published under a Attribution-Non Commercial 4.0 International (CC BY-NC 4.0), (https://creativecommons.org/licenses/by-nc/4.0/)

With the support of the American College of Obstetricians and Gynecologists, the American Vein & Lymphatic Society, the American Venous Forum, the Canadian Society of Phlebology, the Cardiovascular and Interventional Radiology Society of Europe, the European Venous Forum, the International Pelvic Pain Society, the International Union of Phlebology, the Korean Society of Interventional Radiology, the Society of Interventional Radiology, and the Society for Vascular Surgery

As the importance of pelvic venous disorders (PeVD) has been increasingly recognized, progress in the field has been limited by the lack of a valid and reliable classification instrument. Misleading historical nomenclature, such as the May-Thurner, pelvic congestion, and nutcracker syndromes, often fails to recognize the interrelationship of many pelvic symptoms and their underlying pathophysiology. Based on a perceived need, the American Vein and Lymphatic Society convened an international, multidisciplinary panel charged with the development of a discriminative classification instrument for PeVD. This instrument, the Symptoms-Varices-Pathophysiology (“SVP”) classification for PeVD, includes three domains—Symptoms (S), Varices (V), and Pathophysiology (P), with the pathophysiology domain encompassing the Anatomic (A), Hemodynamic (H), and Etiologic (E) features of the patient’s disease. An individual patient’s classification is designated as SVP_A,H,E. For patients with pelvic origin lower extremity signs or symptoms, the SVP instrument is complementary to and should be used in conjunction with the Clinical-Etiologic-Anatomic-Physiologic (CEAP) classification. The SVP instrument accurately defines the diverse patient populations with PeVD, an important step in improving clinical decision making, developing disease-specific outcome measures and identifying homogenous patient populations for clinical trials.

Left renal vein transposition for posterior Nutcracker syndrome

Nutcracker syndrome (NCS) is a rare cause of pelvic venous congestion syndrome and is secondary to either compression of the left renal vein in its normal anatomic position by the superior mesenteric artery and aorta or less commonly when the left renal vein is in a retroaortic position, compressed between the aorta and the spine. We herein present a unique case of NCS in a female patient with a history of chronic pelvic pain and venous congestion. We also review the literature and discuss the diagnostic modalities, differential diagnosis, and various open surgical and endovascular options for NCS.

Nutcracker Syndrome: A Single-Center Experience

Nutcracker syndrome, whose prevalence and natural history are still poorly known, is a clinical syndrome caused by left renal vein compression between the superior mesenteric artery and the aorta. Long-term results and treatment outcomes are not well known. Our group aimed to characterize 7 patients diagnosed with nutcracker syndrome in childhood and to describe their clinical manifestations, diagnostic approaches, and mostly their clinical evolution, rate of complications, and treatment outcomes.

Doppler US and CT Diagnosis of Nutcracker Syndrome

Nutcracker syndrome (NCS) is a syndrome caused by compression of the left renal vein (LRV), between the abdominal aorta and the superior mesenteric artery, resulting in hypertension of the LRV and hematuria. Doppler ultrasonography (US) has been commonly used for the diagnosis of NCS. However, several technical issues, such as Doppler angle and sample volume, need to be considered to obtain satisfactory results. In addition, morphologic changes of the LRV and a jetting phenomenon across the aortomesenteric portion of the LRV on contrast-enhanced computed tomography (CECT) are diagnostic clues of NCS. With proper Doppler US and CECT, NCS can be diagnosed noninvasively.

Cross-sectional imaging of acute gynaecologic disorders: CT and MRI findings with differential diagnosis-part I: corpus luteum and haemorrhagic ovarian cysts, genital causes of haemoperitoneum and adnexal torsion

Acute gynaecologic disorders are commonly encountered in daily clinical practice of emergency departments (ED) and predominantly occur in reproductive-age women. Since clinical presentation may be nonspecific and physical findings are often inconclusive, imaging is required for a timely and accurate diagnosis. Although ultrasound is the ideal non-invasive first-line technique, nowadays multidetector computed tomography (CT) is extensively used in the ED, particularly when a non-gynaecologic disorder is suspected and differential diagnosis from gastrointestinal and urologic diseases is needed. As a result, CT often provides the first diagnosis of female genital emergencies. If clinical conditions and scanner availability permit, magnetic resonance imaging (MRI) is superior to CT for further characterisation of gynaecologic abnormalities, due to the excellent soft-tissue contrast, intrinsic multiplanar capabilities and lack of ionising radiation.

The purpose of this pictorial review is to provide radiologists with a thorough familiarity with gynaecologic emergencies by illustrating their cross-sectional imaging appearances. The present first section will review the CT and MRI findings of corpus luteum and haemorrhagic ovarian cysts, gynaecologic haemoperitoneum (from either ruptured corpus luteum or ectopic pregnancy) and adnexal torsion, with an emphasis on differential diagnosis. Additionally, comprehensive and time-efficient MRI acquisition protocols are provided.

Nutcracker Syndrome in Children: Role of Doppler Ultrasonographic Indices in Detecting the Pattern of Symptoms

The purpose of this study was to evaluate the clinical characteristics of 44 pediatric patients who were diagnosed as having nutcracker syndrome (NCS). We also investigated the left renal vein Doppler ultrasonography (DUS) results, to determine whether or not there was an association between clinical symptoms and DUS findings among these patients. The clinical data from 44 pediatric patients who were diagnosed as having NCS from January 2008 to December 2015 were retrospectively reviewed. We grouped the patients according to the presenting symptoms as symptomatic (loin pain; macroscopic hematuria or both) and non-symptomatic (microscopic hematuria and proteinuria were detected incidentally) and evaluated the left renal vein DUS indices in these two groups separately. Asymptomatic NCS was found in 27 (61.4%) patients; 21 (47.7%) of whom were admitted for the evaluation of proteinuria. The most frequent presenting symptoms were left flank pain (20.5%) and macroscopic hematuria (13.6%); and 2 (4.5%) patients presented with a combination of left flank pain and macroscopic hematuria. The mean ratio of the diameter of the hilar portion of the left renal vein (LRV) to that of the aortomesenteric portion was 4.36 ± 1.55. The mean ratio of the peak velocity (PV) between the two sites of the LRV was 7.32 ± 2.68 (3.1–15.6). The differences in the ratio of the diameters were statistically significant between the two groups and significantly higher in children with asymptomatic NCS (p = 0.025). The PV ratios of the LRV (p = 0.035) were significantly higher in asymptomatic children with NCS than in the symptomatic group. Our study identifies that increased compression ratio of the LRV entrapment is most observed in orthostatic proteinuria and microscopic hematuria.