Pelvic venous disorders: current diagnostic and therapeutic approach

Introduction

Pelvic venous disorders (PeVD) are increasingly becoming the focus of numerous studies. Researchers are attempting to determine the exact cause and the algorithm for management. Patients with pelvic pain seek assistance from specialists in various fields of medicine. Symptoms may present in gynecological, neurological, musculoskeletal, gastrointestinal, urological, vascular, or psychiatric contexts [1]. Chronic pelvic pain is defined as pain lasting more than 6 months, causing difficulties in daily functioning and requiring medical care [2]. The main symptoms reported by women are: a feeling of a weight pressing down on the pelvic area, which intensifies with prolonged standing and painful menstruation, dyspareunia, or sudden urination [3,4]. This is a problem affecting approximately 15% of women aged 18-50 in the United States and as many as 27% worldwide [5]. In search of an effective treatment, 12% of women opt for hysterectomy, 40% decide to undergo diagnostic laparoscopy, yet only half of them obtain a definitive explanation regarding the cause of their symptoms [6]. Diagnostic difficulties are caused by conditions that present with similar symptoms such as neuropathic pain, chronic lower back pain, irritable bowel syndrome, interstitial cystitis and endometriosis. This prolongs the diagnostic process and delays the initiation of appropriate treatment, which is a source of frustration and prolonged pain for patients [7].

Material and methods

A review of publications available on PubMed and Google Scholar was carried out using a combination of specific key words such as: pelvic venous disorders, pelvic varicose veins, pelvic venous insufficiency, chronic pelvic pain.

Classification

For a long time, diagnoses such as May-Thurner syndrome, nutcracker syndrome, or pelvic congestion syndrome were diagnosed as separate pathologies related to the abdominal and pelvic veins. The term PeVD was introduced to encompass all pelvic venous pathologies under a unified concept. To further organize these conditions and enable objective comparison, the Symptoms-Varices-Pathophysiology (SVP) classification was developed, providing a structured framework for diagnosis, research, and treatment standardization [8]. The SVP classification was proposed by the American Vein and Lymphatic Society (AVLS), which convened an international multidisciplinary panel to develop criteria for assessing women with pelvic pain symptoms. Based on expert opinions and available literature, a system was created – SVP – which is based on three fundamental pillars: symptoms (S), varices (V), and pathophysiology (P), which specifies the anatomical (A), hemodynamic (H), and etiological (E) characteristics of the patient [9]. Each patient is classified individually as SVP A, H, E. In a significant group of patients, classifications can be combined with a complementary system for classifying chronic venous insufficiency of the lower limbs (CEAP). The SVP system was created to facilitate the categorization of patients, whereas it is not suitable for assessing the severity of the disease, its progression, or the response to treatment [8]. Table 1 presents the classification described above.

Pathophysiology

Knowledge and understanding of the basic venous anatomy within the abdominal cavity, pelvis, and proximal segments of the lower limbs is essential for comprehending the pathogenesis of pelvic venous disorders. The primary route of venous outflow within the pelvis of women consists of the ovarian veins and the iliac veins. The right ovarian vein drains directly into the inferior vena cava, while on the opposite side, the blood path is longer, as the left ovarian vein connects with the left renal vein before draining into the superior vena cava. This results in asymmetric drainage within the pelvis and increased pressure on the left side. Blood from the internal iliac veins flows into the common iliac veins, which merge to form the inferior vena cava. The aforementioned drainage of the pelvis and abdominal cavity occurs through four interconnected systems – the ovarian veins, iliac veins, left renal vein, and superficial veins of the lower limbs [10].
One of the most important risk factors for PeVD is pregnancy. Due to increased blood volume and hormonal changes, there is increased circulation of blood within the ovarian and uterine veins and venodilation caused by high estradiol levels. The vasodilatory effect increases the load on the venous valves and the increased intrauterine pressure intensifies reflux in the ovarian veins [11,12].
The hormonal cause of pelvic venous disorders is confirmed by the reduction in the severity of symptoms after menopause. Estrogen is the hormone responsible for the vasodilatory component, which may exacerbate venous insufficiency, one of the causes of PeVD. To date, there have been isolated documented cases of patients who report alleviation of symptoms and meet the criteria for pelvic venous disorders [13].
Failure or absence of venous valves is also one of the significant risk factors. Venous valves are usually found in the distal portion of the ovarian vein, near the junction with the renal veins. Some women lack venous valves in the ovarian veins, most often on the left side [14].
The anatomical cause of pelvic venous insufficiency may originate from the compression of the left common iliac vein between the right common iliac artery and the lumbar segment of the spine, resulting in retrograde blood flow in the left iliac veins and then the outflow through other pelvic veins. Similarly, the compression of the left renal vein between the superior mesenteric artery and the aorta, which is defined as the nutcracker syndrome, leads to venous outflow disturbances from the left kidney area, causing pain along with hematuria [10].

Symptoms

The most commonly reported symptoms in women with pelvic venous disorders are chronic pain, pelvic and vulvar varices, as well as atypical venous dilatations in the lower limb. The pain is described as unilateral or bilateral, non-cyclical, pulsating, and located at the level of the pelvis. The intensity increases after prolonged periods of standing and movement. Sometimes patients describe the occurrence of a sharp, stabbing pain. Tenderness at the level of the ovaries, pain persisting after childbirth, and exacerbation of symptoms after maintaining a prolonged standing position are all characteristic of chronic pelvic pain [15,16].
Dyspareunia, menorrhagia and pain at the end of the cycle are among the symptoms more frequently reported by women with PeVD. The occurrence of varicose veins in the pelvic area, gluteal area or on the medial surfaces of the thighs suggests incompetence of the superficial veins, which can be attributed to the presence of venous congestion in the pelvic area. In turn, urological complications of venous insufficiency can manifest as frequent urination, pain and burning during urination, or a feeling of incomplete emptying of the bladder. Symptoms of proctological character, such as hemorrhoids, perianal pain and discomfort, should shift the attending physician’s attention towards a possible diagnosis of PeVD.
The patients who should conduct further diagnostic evaluation regarding chronic pelvic pain (CPP) are women over the age of 30, reporting an increase in symptoms with each pregnancy [9]. Many conditions can cause symptoms related to pain in the pelvic and abdominal areas, complicating and delaying the establishment of an accurate diagnosis in women. Therefore, it is crucial to exclude as many conditions as possible associated with chronic pain complaints. Table 2 presents examples of such diseases [17].

Diagnostics

Phlebography was historically the gold standard for assessing PeVD, but its role has started to evolve with advancements in non-invasive imaging techniques. Currently, ultrasound (US) is the first-line diagnostic method. Before initiating treatment, cross-sectional imaging is necessary, as it provides the most valuable information required for effective therapy. Magnetic resonance venography (MRV) is the preferred method, while computed tomography venography (CTV) is inferior to MRV in several key aspects: it has lower soft tissue resolution, provides poorer visualization of small-caliber veins, cannot differentiate other potential causes of symptoms, and requires radiation as well as an iodine-based contrast medium. Phlebography, being an invasive procedure that involves the use of contrast media and ionizing radiation, is used mostly during endovascular treatment, where it can confirm findings from other imaging modalities or resolve any diagnostic uncertainties.
Ultrasonography is performed using transabdominal, transvaginal, and transperineal approaches. The advantage of US, regardless of the selected approach, is the ability to perform a dynamic assessment under conditions that reflect real physiological load, including different body positions and the Valsalva maneuver. Its main drawback, however, is that it is operator-dependent. Both B-mode imaging and Doppler techniques are used. In transabdominal ultrasound, performed in the supine and semi-seated positions, the dimensions of the major venous trunks are assessed: the inferior vena cava (IVC), iliac veins, renal veins, ovarian veins, and uterine venous plexuses. The most commonly proposed cutoff value indicating ovarian vein incompetence is a diameter of the left ovarian vein (LOV) and right ovarian vein (ROV) > 6 mm [18]. The positive predictive value for a 6 mm diameter is 83.3% [19], while dilated uterine venous plexuses are defined as the presence of more than four vessels with a diameter > 4 mm [16]. The additional use of Doppler options allows for the visualization of reflux and measurement of its duration. There is no validated reflux time to confirm ovarian vein incompetence [18]. In one study [19], reversed flow in the ovarian veins correlated accurately with reflux presence in phlebography. The assessment of ROV is more demanding than LOV, as dilation of this vein may result not only from incompetence but also from compensatory enlargement [18].
In transvaginal ultrasound (TVUS), which is also used to exclude other pelvic or gyneacological pathologies, it is possible to evaluate the diameter of the uterine venous plexuses, arcuate veins within the myometrium, and the presence of reflux during the Valsalva maneuver. The biggest disadvantage of this method is its limited field of view and difficulty in visualizing the ovarian veins over a longer segment [18]. Tortuous uterine venous plexuses with a diameter > 5 mm are considered to have undergone varicose transformation [19]. The same threshold (> 5 mm) applies to dilated arcuate veins of the myometrium that connect the left and right sides, although this parameter has low specificity (25%) [19]. The dilation of any pelvic vein or uterine venous plexus > 8 mm has been proposed as a criterion for diagnosing PeVD, with a sensitivity of 86.1% and specificity of 66.7% [20]. Additionally, in patients with PeVD, ovarian cystic changes are observed more frequently than in the healthy population, which results from venous stasis and hyperstimulation with estrogens [19].
Perineal ultrasound is performed to assess incompetent leakage points from the pelvis in the perineal and gluteal regions, as well as to evaluate the origin of atypical lower limb varicosities.
The imaging modality providing the most comprehensive information is MRV of the abdomen and pelvis. However, all cross-sectional studies have a drawback – the supine position of the patient, which is non-physiological for evaluating reflux presence. As previously mentioned, in addition to vascular information, pelvic MR imaging provides insights into other conditions that may cause CPP, such as endometriosis and adenomyosis [21]. Modern vascular sequences (e.g., balanced steady-state sequences) allow for the anatomical assessment of pelvic veins without the need for gadolinium-based contrast agents, making it possible to evaluate large venous trunks, potential compression at the level of the left renal vein and left common iliac vein, pelvic venous plexuses, leakage sites from the pelvis, atypical lower limb and gluteal varicosities. Dynamic sequences, such as 4D-TRAK, TWIST, or TRICKS, which require contrast administration, enable real-time venous flow imaging, allowing for reflux assessment in major venous trunks and functional analysis of the venous system, e.g., during the Valsalva maneuver [22].
A systematic review by Steenbeek et al. demonstrated that the sensitivity of MR in detecting pelvic congestion syndrome (PCS) ranges from 88% to 100%, indicating the high effectiveness of this method in identifying pelvic venous pathology. However, specificity, or the ability to correctly exclude PCS, was more variable and ranged from 38% to 100%, depending on the imaging technique used [23]. Currently, the available studies on MR diagnostic utility are limited, and each employs a different scanning protocol, necessitating further research to establish its validity.
Some centers also use CTV, although it is inferior to MRV due to factors such as lower soft tissue resolution and significantly poorer vessel contrast – especially for small-diameter veins. Key advantages of CTV include cost, availability, shorter scan duration, and greater ease of execution compared to MRV (MR imaging requires specialized, less commonly available protocols and trai-ned electroradiologists). Computed tomography allows for the evaluation of major venous trunks in the venous phase and the assessment of indirect reflux indicators (ovarian vein diameter > 6 mm or the presence of pelvic varices). In some cases, direct reflux features can be observed, such as contrast retention in the LOV during the late arterial phase, but this assessment is significantly inferior to dynamic MR venography. The evaluation of small veins and uterine venous plexuses in CT is often impossible.
Phlebography remains the reference standard for non-invasive imaging [24]. It requires venous puncture of the jugular, brachial, or femoral vein and selective contrast injection into the ovarian and internal iliac veins. This procedure is more expensive, requires more personnel, takes longer, and necessitates access to angiographic suite. The examination is performed during normal breathing and during the Valsalva maneuver. Features of venous incompetence include: dilation and retrograde filling of the ovarian veins along their entire length, contrast stasis (> 20 seconds in dilated plexuses), abnormal contrast flow through pelvic veins (e.g., across the midline, into the vulvovaginal plexuses, or into thigh varicosities), and retrograde opacification of the internal iliac vein branches [22,25,26].

Treatment

Due to the complex and unclear etiology of chronic pelvic pain, the initiation of treatment should be based on the exclusion of acute conditions. Pain management should begin with behavioral treatment and should be supported by pharmacological treatment. Given the chronic nature of the condition and the significant psychological burden, patients should seek psychological assistance during treatment [27].
Various pharmacological agents include gonadotropin-releasing hormone (GnRH) agonists, danazol, combined oral contraceptives, progestins, phlebotonics, and non-steroidal anti-inflammatory drugs [28]. Other options include an etonogestrel implant, goserelin, or medroxyprogesterone acetate [29]. However, oral treatment does not provide sustained relief and is associated with undesirable effects, including menstrual irregularities, weight fluctuations, and reduced bone density. Treatment with venoactive drugs is associated with CPP relief but without affecting neuroinflammatory mediator levels (calcitonin gene-related peptide – CGRP; substance P – SP), whereas embolization/surgery not only relieves CPP and eliminates pelvic venous reflux, but also significantly reduces CGRP and SP levels [30].
Minimally invasive endovascular techniques are now the treatment of choice, offering fewer adverse effects and shorter hospitalization compared to surgical treatment. There are multiple possible embolization strategies: embolization of one or both ovarian veins, additional embolization of uterine veins (four-vein embolization), and embolization of other branches of the internal iliac veins, particularly the internal pudendal and obturator veins. The literature describes the use of various embolic and sclerotic materials, including pushable and detachable coils, occluders, glue, polymers, either used alone or in varied combination with polidocanol or sodium tetradecyl sulfate (STS) [31]. Because of the absence of strict guidelines for the treatment of PeVD, the Society for Vascular Surgery and the American Venous Forum recommend embolization as a level 2B treatment option [32]. The choice of method depends on the experience and skill of the operator, as no significant differences in efficacy have been proven.
The absence of standardized tools for evaluating PeVD treatment outcomes makes it difficult to compare studies and draw clear clinical conclusions. In a scoping review, significant heterogeneity in reported outcomes was found, with only 13.7% of studies including quality of life measures, despite their clinical importance [33]. No validated Core Outcome Set (COS) currently exists, and outcome reporting remains inconsistent [33]. Additionally, although many classification scales have been proposed, none are widely accepted, and only three have been formally validated [34]. This lack of standardization limits objective comparison of treatment strategies and highlights the need for unified diagnostic and evaluation tools in PeVD research [33,34].
Multiple clinical studies have consistently demonstrated that endovascular embolization is an effective treatment for PeVD. In seven of the reviewed trials, pain severity was assessed using the Visual Analog Scale (VAS) [35-41]. Baseline VAS scores ranged from 7.4 to 9.0, with post-treatment values decreasing to between 0.91 and 3.6, corresponding to a reduction of 3.6 to 6.5 points. In several studies, symptom relief was sustained over long-term follow-up, extending up to 5 years [38,40].
The proportion of patients reporting complete or significant clinical improvement ranged from 70.7% to 95.5% [36-40,42]. Clinical success rates above 89% were reported in three studies, with one study documenting 100% symptom resolution after three years of follow-up [37,38,40]. The lowest improvement rate (70.7%) was observed in a retrospective analysis, where approximately 30% of patients experienced no clinical benefit [36].
Several studies have reported improvement in symptoms beyond pelvic pain following embolization for pelvic venous disorders. In the retrospective study by Zhou et al., both treatment groups – coils with glue and coils with sclerosant – demonstrated significant relief of dyspareunia and posture-related discomfort (sitting/standing), with no significant difference between them [41]. In a long-term follow-up study, Gavrilov et al. reported complete symptom resolution in 77.6% of patients after one month and in 95.5% after three years. The assessed symptoms included dyspareunia, lower back pain, dysuria, tenesmus, and menstrual-related discomfort [37]. Van der Vleuten et al. used a multidimensional symptom questionnaire and found clinical improvement in 66.7% of patients at 2 months and 76.2% at final follow-up. The evaluation covered symptoms such as pelvic heaviness, dyspareunia, urinary frequency, and menstrual issues [42]. These findings support the role of embolization in addressing a wide range of functional and quality-of-life-related symptoms in PeVD, although standardized assessment tools remain limited. Across all studies, various embolic agents were utilized – including coils, vascular plugs, tissue adhesives, and sclerosing agents, either alone or in combination [35,40-42]. No significant differences in clinical effectiveness were found between the different embolization materials.
Recurrence of symptoms after embolization has been reported in numerous studies. Rates ranged from 3.4% to 18.8% in long-term follow-up [4,36,40-42]. In the largest cohort, recurrence occurred in 3.4% of patients treated with vascular plugs and 6.5% of patients treated with coils [40]. Smak Gregoor et al. observed recurrences in 11% of patients, with a median delay of 35 months; 4 out of 10 patients undergoing repeat embolization achieved partial symptom relief, while the remainder did not improve [36]. In the study by Zhou et al., re-intervention in 63% of 31 patients with recurrent symptoms led to a renewed reduction in pelvic pain (VAS scores) in both the coils-plus-glue and coils-plus-foam groups, with no significant differences between them. No details regarding the reintervention technique were provided [41]. In Van der Vleuten’s study, 42.9% of patients required a second embolization, but further benefit was not observed in those who failed to respond initially [42].
Secondary forms of pain-predominant pelvic venous disorders can result from outflow obstruction syndromes such as May-Thurner syndrome (MTS) or nutcracker syndrome (NCS), and are now integrated into structured classifications such as SVP. Their recognition is crucial, as it fundamentally alters patient management and requires addressing the primary underlying cause of symptoms. The optimal treatment strategy for pelvic venous disorders remains a matter of debate in the literature. While some authors report symptom relief following stent implantation, others advocate embolization as the initial step. There are no standardized recommendations regarding the type or dimensions of stents to be used in PeVD; selection typically depends on the operator’s preferences and experience. Importantly, the decision to implant a stent should be guided by the overall clinical context, as venous stenosis is frequently observed even in asymptomatic patients. In the studies mentioned below, patient qualification was based on the presence of symptoms and imaging evidence of iliac vein stenosis exceeding 50% of the vein diameter. In a study by Lakhanpal et al., patients with iliac vein stenosis and the presence of reflux in the ovarian veins were treated with stenting the iliac vein alone, and most of them showed remission of symptoms [43]. 29/38 patients reported remission of all symptoms after treatment in 6-month follow-up. In the subgroup of patients diagnosed with a “pelvic reservoir” pattern on phlebography, the rate of complete clinical response was lower, at 58%. Trześniowski A et al. reported a retrospective study involving 141 women with PeVD characterized by iliac vein stenosis (IVS) and ovarian vein reflux (OVR) [44]. The treatment involved stent implantation from the inferior vena cava IVC to the left external iliac vein in 83% of patients, and from the IVC to the right external iliac vein in 13%. Most patients were satisfied with the improvement in their symptoms, and only 19 required reintervention [44]. The real improvement in women’s daily functioning was reported in a 5-year study involving 113 women with chronic pelvic pain treated exclusively with venous stenting, without concomitant ovarian vein embolization [45]. After the procedure, 98% of patients reported pain improvement, and 73% experienced complete pain resolution. Despite technically successful interventions, postoperative care remains essential. Due to the lack of official guidelines and limited data, the use of anticoagulant therapy remains a controversial topic. Current literature supports an individualized approach to initiating pharmacological therapy.
Classical surgery was used to treat pelvic venous disorders even before the development of dedicated endovascular techniques. The earliest procedures included hysterectomy with or without oophorectomy, followed by open extraperitoneal ovarian vein resection. Later, laparoscopic ovarian vein ligation was introduced [46]. Although early outcomes were favorable, this approach was largely abandoned due to a high rate of complications, such as retroperitoneal hematoma, ureteral injury, and adhesive disease. However, less invasive methods have since become the standard of care due to their lower complication rates. Notably, some centers still perform laparoscopic ligation, with good results; for example, Gavrilov et al. reported over 95% clinical improvement after surgical treatment in a comparative study with embolization [37]. Despite the effectiveness of both approaches, universal treatment algorithms and guidelines for primary care providers remain lacking.
The selection of a minimally invasive approach appears to be the safest treatment option for patients, although it is not entirely free from complications. One of the most common adverse effects is post-embolization syndrome, occurring in approximately 20% of patients. It is characterized by increased pelvic pain, low-grade fever, and tenderness over the embolized vein, and typically resolves with nonsteroidal anti-inflammatory drugs (NSAIDs) [47]. Other possible complications include vessel perforation, hematoma, local thrombophlebitis, contrast reactions, and symptom recurrence. A more serious but rare complication is coil or vascular plug migration, most often associated with embolization of the internal iliac vein [48]. The most frequently reported complication following stent implantation is back pain, which is believed to be related to stent oversizing. Up to 66% of patients experience severe back pain lasting more than one week, although symptoms generally resolve within one month [49].

Conclusions

Venous disorders of the pelvis occur in the form of various ailments and are a common issue among women of reproductive age. Due to the lack of a clear definition and an established diagnostic algorithm, the diagnosis is often delayed, leading to prolonged, ineffective treatment and a decline in the quality of life for patients. Problems related to pelvic venous insufficiency may encompass the fields of gynecology, vascular surgery, interventional radiology, and urology. Successfully identifying the affected group of patients and outlining alarm symptoms will facilitate the process of diagnosis and referral of patients to the appropriate specialists, which will contribute to the quicker implementation of endovascular or surgical interventions and effective treatment of the underlying issue. It is necessary to develop a common, universal algorithm that will streamline and expedite the processes of diagnosis and treatment.

Disclosures

1. Institutional review board statement: Not applicable.
2. Financial support and sponsorship: None.
3. Conflicts of interest: None.

References