Introduction

Pelvic congestion syndrome (PCS), also known as pelvic venous insufficiency, is a chronic condition causing pelvic pain. PCS occurs when varicose veins develop around the ovaries in the setting of chronic pelvic pain (CPP). Similar to varicose veins in the legs, pelvic varicosities are thought to result from a combination of dysfunctional venous valves, retrograde blood flow, and venous engorgement [1].

Prevalence

PCS, or pelvic venous insufficiency, initially described around the 1850s, and correlated with pelvic pain in the 1940s–50s, is now a well-characterized etiology of PCS [2]. PCS typically affects women of reproductive age. Worldwide, rates of CPP, for women of childbearing age, range from 14% to 43% [2, 3]. CPP rates in the United States are approximately 15% for women of childbearing age [4]. Congested pelvic veins can be quite painful and can account for a range of 10%–40% of cases of CPP [1,2,5]. No cases have been reported in postmenopausal women [5].

Anatomical Considerations

The complex arena of venous circulation of the female pelvis must be considered when evaluating patients for PCS, as these plexuses are uniquely interconnected: the left renal and ovarian veins, the iliac veins (common, external, and internal), and the lower extremity veins. In addition to communications between these systems, there is also frequent crossover, from side to side. In the female pelvis, the ovarian veins drain blood flow from the parametrium, cervix, mesosalpinx, and pampiniform plexuses, which may also drain through the internal iliac as a collateral pathway [6]. These plexuses form the ovarian vein, which may have two to three trunks before becoming a single trunk at the level of L4–L6. The ovarian vein has a mean diameter of approximately 3 mm, which increases with pregnancy, and usually has two or three valves, which are incompetent in about 50% of women [6]. Although variations may occur, the right ovarian vein usually drains directly into the inferior vena cava (IVC), whereas the left drains into the left renal vein. The ovarian veins collateralize extensively with the ascending lumbar and peritoneal veins [5]. The internal iliac veins receive inflow from the utero-ovarian, vesicular, hemorrhoidal, and sacral venous plexuses [5]. The two systems, the ovarian, and internal iliac veins, run together in the broad ligament with extensive communication [5].

Pathophysiology

Insufficiency of the pelvic veins arises when there is abnormal dilation or distention of the venous territories between the iliac and ovarian veins. While the precise etiology of PCS remains uncertain, it is likely multifactorial. Valvular insufficiency, venous obstruction, and hormones all may play a role in the development of congestion of the pelvic veins [5]. The cause of pain due to the pelvic congestion remains unclear, but the most likely possibility is that increased dilatation, concomitant with stasis, leads to the release of local pain-producing substances [5]. Insufficiency can be delineated further into primary/intrinsic causes and secondary/extrinsic causes.

Primary venous insufficiency occurs due to either the absence of venous valves or the incompetence of such valves. Congenital absence of ovarian vein valves has been shown in 13%–15% of patients on the left side and in 6% on the right side [5]. Venous valves are incompetent in 41%–43% of women on the left side, and in 35%–46% on the right side [5]. There is higher prevalence of PCS in multiparous women, which may be related to the 50% increase in pelvic vein capacity during pregnancy [5]. This phenomenon can result in valvular incompetence as well as retrograde blood flow. These changes may persist for up to 6 months following pregnancy [5].

Secondary pelvic vein incompetence is related to venous outflow obstruction by extrinsic compression. Possible causes are nutcracker syndrome, wherein the left renal vein is compressed due to entrapment between the abdominal aorta and the superior mesenteric artery, or May–Thurner syndrome, in which the left common iliac vein is compressed by the right internal iliac artery [5]. Rarely, PCS may develop from regional venous overload from congenital venous and arteriovenous malformations due to cirrhosis, retro-aortic left renal vein, tumor thrombosis of the inferior vena cava, portal vein thrombosis, and renal cell carcinoma with left renal vein thrombosis [5].

Diagnosis

A thorough history and physical examination are paramount to achieve proper diagnosis in the case of PCS, especially given that patients with incompetent pelvic veins can be asymptomatic. Other causes of pelvic pain, both chronic and acute, should be ruled in or out based on the clinical history, such as, but not limited to, ovarian torsion, endometriosis, painful bladder syndrome, spastic pelvic floor syndrome, and others. Typical features are shown in Table 10.1 [5].

In a patient with characteristic symptoms, the diagnosis is supported by bimanual examination exhibiting cervical motion tenderness, uterine tenderness, and/or ovarian tenderness. However, patients can also have no pain on exam. A study by Beard reported the combination of tenderness on abdominal palpation over the adnexa compounded by a history of postcoital ache was 94% sensitive and 77% specific for discriminating pelvic congestion from other causes of pelvic pain [5, 7]. Unfortunately, no clear diagnostic algorithm exists for PCS, and therefore a multidisciplinary approach for pelvic pain, utilizing gynecological, urological, vascular, or interventional radiological input may be helpful. Imaging should be performed to support but not define diagnosis, especially given that incompetent and dilated ovarian veins are common, nonspecific findings. Further, although dilatation of the ovarian vein is necessary but not sufficient for diagnosis, there is no consensus on the optimum cut-off for ovarian vein diameter in PCS and no validated measures for venous congestion and tortuosity. Furthermore, the reported cut-off values for ovarian vein diameter differ between the imaging techniques [5].

Predisposing risk factors for the development of PCS are those of most women alive today: being of reproductive age. Pregnancy and its changes on total blood volume, and the distribution of said volume, are an obvious predisposing factor. However, there are cases of PCS in patients without prior pregnancy. This may be due to intrinsic issues with the veins, or lifestyle choices in which intraabdominal pressure is routinely increased, such as patients who must stand for prolonged periods of time, routinely lift heavy objects, or engage in extreme sports, such as skydiving or bungee-jumping. In all these cases, increased intraabdominal pressure is common denominator. However, we must note here the effect of estrogen, which can act as a vasodilator, causing smooth muscle relaxation and loss of vascular responsiveness [5]. This effect may explain why these symptoms improve with time and the parallel decline of estrogen, as there is complete regression of symptoms after menopause [5].

Imaging

Ovarian venography is, and has been, the gold standard for diagnosis [6]. Initially published by Beard et al. in 1984, these criteria included ovarian diameter of 6 mm or greater, contrast retention in the pelvic venous plexus of more than 20 seconds, congestion of the pelvic venous plexus and/or opacification of the ipsilateral (or contralateral) internal iliac vein, and/or filling of vulvovaginal and thigh varicosities.

Each variable was assigned a value of 1 to 3, depending on the degree of abnormality, with a score greater than 5 indicating PCS [7]. A benefit of contrast venography is that the tool is both diagnostic and therapeutic, after which sclerotherapy or embolization may be performed. These treatments will be discussed later in the chapter. However, numerous less invasive imaging options are available.

Ultrasound

Ultrasound imaging is the least invasive imaging testing available to date. It is helpful in that it can thoroughly evaluate pelvic anatomy, as well as include or exclude other etiologies of pain. PCS can be suspected in patients with dilation of ovarian vein greater than 4 mm, reversed or retrograde blood flow, slow blood flow (<3 cm/second), presence of tortuous and or dilated veins, dilated arcuate veins crossing the uterine myometrium, or variable duplex waveform in the varicoceles during Valsalva maneuver [5]. However, the ability to obtain such detail is operator dependent, so further workup may be warranted.

Both CT and MRI offer detailed cross-sectional imaging of both anatomy and pelvic vasculature. Both modalities are sensitive for pelvic varices, ovarian vein dilation, and compression of iliac and renal veins [5]. Unfortunately, CT requires radiation, and neither modality provides hemodynamic information, a clear benefit of duplex ultrasonography. Duplex ultrasound has become the diagnostic test of choice in most venous centers [6]. Additionally, as these two modalities typically require the patient to be positioned in the supine position, there is concern for less specificity of results.

Laparoscopy is often performed in patients with pelvic pain. The rate of any pathological findings at time of laparoscopy, in women with CPP, is 35%–83%, however, the rate of PCS seen at time of laparoscopy is 20% [5]. PCS is likely to be missed at the time of laparoscopy due to CO₂ insufflation and Trendelenburg position causing venous collapse [5]. Therefore, laparoscopy should not be considered a first-line diagnostic tool for PCS [5].

Table 10.2 summarizing these imaging modalities as described by Borghi et al details these issues.

Complications/Fertility

There is scant information in the literature regarding rate of pregnancy and associated outcomes after treatment for PCS, regardless of modality. The procedure appears to do no harm to ovarian function, as no significant differences in hormone levels were observed before and after therapy [8]. Additionally, reports about pregnancy and ovary hormone levels after embolization are also rare [8]. Further studies are warranted.