Renal Doppler ultrasonography in the diagnosis of nutcracker syndrome

Left renal vein entrapment syndrome: nutcracker syndrome!

Nutcracker syndrome (NCS) is a rare vascular compression disorder that involves compression of the left renal vein most commonly between the aorta and the superior mesenteric artery (SMA), although variations exist. It is associated with the formation of the left renal vein from the aortic collar during the 6th-8th week of gestation and abnormal angulation of the SMA from the aorta. Collateralisation of venous circulation including mainly the left gonadal vein and the communicating lumbar vein are the most significant effects. It has a female predilection occurring in the third to fourth decade and it tends to be diagnosed earlier in men. Affected individuals may present with a myriad of symptoms such as haematuria, left flank pain and proteinuria. As patients often present with these non-specific symptoms to primary care, knowledge of NCS is essential. The diagnosis can be rendered with Doppler ultrasonography, retrograde venography, CT angiography, intravascular ultrasound and magnetic resonance angiography. The authors describe the case of a 39-year-old woman with a low body mass index (BMI) presenting with generalised abdominal and flank pain as well as chronic microcytic anaemia. Physical examination findings were suggestive of biliary or renal colic. Laboratory investigations confirmed her anaemia (haemoglobin 88 g/L, mean corpuscular volume (MCV) 72 fL), but were otherwise unremarkable. Urinalysis showed proteinuria and haematuria. However, ultrasonography was unremarkable with a normal gallbladder and no evidence of calculi. Her CT scan showed marked compression of the left renal vein between the aorta and the SMA (nutcracker phenomenon), with upstream left renal, left gonadal and left lumbar vein dilatation. She was managed conservatively. This paper provides an overview of the aetiology, embryology, clinical manifestations, imaging modalities and management of NCS.

Salvage Renal Autotransplant Following Previous Renal Vein Stenting in Nutcracker Syndrome

OBJECTIVES

Nutcracker syndrome is rare, and a proportion of patients with this syndrome continue to have intractable pain and symptoms. Due to the heterogeneity of patients' chief complaints and symptoms, the surgeon's preferred approach may be inherently different but is of paramount importance to the outcome.

MATERIALS AND METHODS

We present 4 cases in which renal autotransplant with extraction and ligation of previously placed gonadal coils was performed following previously attempted renal vein stenting or combined renal vein transposition followed by renal vein stenting.

RESULTS

Autotransplant resulted in flank pain resolution with improvement in symptoms associated with pelvic congestion syndrome.

CONCLUSIONS

The approach to such cases requires meticulous and adequate vena cava exposure, with preparation for potential caval reconstruction. No firm inferences can be made from such a small series; however, we believe in renal autotransplant as first-line therapy, and failure after an initial renal vein stent should be salvaged by renal autotransplant over further endovascular attempts.

Evaluation of posterior nutcracker phenomenon using multisection spiral CT

AIM

To prospectively evaluate the epidemiological, anatomical classification, clinical importance, and radiological features of posterior nutcracker phenomenon (PNP) in patients examined with multisection spiral computed tomography (MSCT).

MATERIAL AND METHODS

Patients who underwent abdominal enhanced MSCT from January 2012 to July 2016 were evaluated retrospectively. Combined with the blood, normal biochemistry, and urine tests, patients were assessed retrospectively for renal vein diameter measurements, the compression ratio of blood vessels, gender differences, anatomical classification, percentage of proteinuria and haematuria, and clinical symptoms.

RESULTS

The study included 6,225 consecutive patients, PNP was observed in 2.06% involving the CLRV in 1.22% and retro-aortic left renal vein in 0.84%. The proportion of posterior nutcracker syndrome (PNS) was lower in PNP (17.2%). There was no difference by sex and age in the prevalence of PNP (p>0.05). In patients with urological symptoms, the number of type II abnormalities was more frequent than type Ia and type Ib abnormalities. Meanwhile, the number of type II abnormalities was frequent than the other two types. There was a significant difference between PNS and asymptomatic PNP (aPNP) in all measured values (p<0.001), the ratio was >4, especially in type II abnormalities (ratio >5.0).

CONCLUSIONS

PNP is a type of left renal vein entrapment. It is exceptionally rare and might be underdiagnosed. MSCT and measured values can be useful in diagnosis and recognition.

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.

Minimally invasive treatments for venous compression syndromes

The management of venous compression syndromes has historically been reliant on surgical treatment when conservative measures fail. There are, however, several settings in which endovascular therapy can play a significant role as an adjunct or even a replacement to more invasive surgical methods. We explore the role of minimally invasive treatment options for three of the most well-studied venous compression syndromes. The clinical aspects and pathophysiology of Paget-Schroetter syndrome (PSS), nutcracker syndrome, and May-Thurner syndrome are discussed in detail, with particular emphasis on the role that interventionalists can play in minimally invasive treatment.

Venous compression syndromes: clinical features, imaging findings and management

Extrinsic venous compression is caused by compression of the veins in tight anatomic spaces by adjacent structures, and is seen in a number of locations. Venous compression syndromes, including Paget-Schroetter syndrome, Nutcracker syndrome, May-Thurner syndrome and popliteal venous compression will be discussed. These syndromes are usually seen in young, otherwise healthy individuals, and can lead to significant overall morbidity. Aside from clinical findings and physical examination, diagnosis can be made with ultrasound, CT, or MR conventional venography. Symptoms and haemodynamic significance of the compression determine the ideal treatment method.