One may argue that the current study is a case of ovarian torsion simultaneously with an event of VTE; however, we believe there is no need to debate as it is virtually impossible to confirm the relationship between ovarian torsion and VTE. The clinical significance of this study is to remind physicians that 1) VTE could occur after ovarian detorsion during pregnancy; 2) Early ambulation and anti-embolism stockings may not prevent VTE and therefore 3) the epidemiology, diagnosis and treatment regimens should be reviewed due to its rarity and complexity regarding to foetal health during pregnancy.
Current research status
About 10–22% of adnexal torsion occurred during pregnancy [6, 7]. It is more likely to occur between the 10th week and the 17th week of gestation with an ovarian mass larger than 4 cm in diameter [8]. The venous thromboembolism risk was reported to be 0.03% in pregnant women, which is increased by 5 folds as compared to non-pregnant women [9, 10]. The above-mentioned data were mainly focused on the population of pregnant women. In addition to that, to the best of our knowledge, the subgroup of pregnancies with VTE after ovarian torsion-detorsion has seldom been evaluated. A comprehensive search was performed in Embase and PubMed. The search strategies were designed using controlled vocabulary and plain language without language restrictions (Supplementary material). As a result, there has been only one case of VTE and three cases of pulmonary embolism (PE) in patients with adnexal torsion in the literature across the globe. Three of four cases received adnexal resection without detorsion and all of the three cases were complicated with PE. One of four cases received cystectomy with detorsion and developed postoperative DVT. However, none of the cases occurred during pregnancy [Table 1]. Therefore, we are the first to present a case of an ovarian torsion in a pregnant woman which has been complicated with VTE after the surgical intervention with ovarian detorsion.
Table 1
Reports of venous thromboembolism after adnexal torsion
Author, year | age | Pregnant/non-pregnant | Torsion site | Surgery | Thromboembolic event |
Jauch,1922(15) | 19 | non-pregnant | Fallopian tube | Salpingectomy without detorsion | Pulmonary embolism |
McGovern,1999(11) | 38 | non-pregnant | Fallopian tube | Salpingectomy without detorsion | Pulmonary embolism |
McGovern,1999(11) | 16 | non-pregnant | Left ovarian torsion | Detorsion + Cystectomy | deep vein thrombosis (right iliac vein) |
McGovern,1999(11) | 44 | non-pregnant | Right adnexal torsion | Right salpingo-oophorectomy without detorsion | Pulmonary embolism |
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Epidemiology
In order to evaluate the epidemiological characteristics of pregnancies with post-detorsion VTE, we reviewed all of the medical records of our hospital from September 1991 to September 2019. Consequently, there were totally 256086 deliveries, out of which 260 cases had adnexal torsion and 17 cases had isolated fallopian tube torsion, amounting to an incidence of 0.11% and 0.007%, respectively. Of the 260 cases, 223 had ovarian tumour and 1 case developed VTE after the surgical detorsion, giving an incidence of 0.38% (Fig. 1 flow diagram).
Evaluation and diagnosis
The diagnosis of VTE after ovarian torsion-detorsion during pregnancy mainly depends on the clinical symptoms, physical examination and imaging tests. Patients with deep vein thrombosis (DVT) may present with calf pain, swelling and tenderness in the leg and a positive Neuhof's sign. On the other hand, those who develop iliac vein thrombosis may complain of inguinal, pelvic, or abdominal pain, and experience swelling of the entire leg. Pregnant women with a high suspicion of DVT should undergo a D-dimer test and compression ultrasonography (CUS). If the initial CUS is negative, repeat CUS must be performed when there is a high index of suspicion. In comparison with DVT, PE is more challenging to diagnose as the clinical presentation may be non-specific. One should be cautious of PE when the patient complains of weakness and faintness, which is usually considered as the normal recovery process after the surgical detorsion and is therefore neglected. Some may experience tachycardia and tachypnea [11]. Under such circumstances, a computed tomography pulmonary angiogram (CTPA) is highly recommended [12]. CUS should be performed after the confirmation of PE as DVT and PE are usually associated. In our study, the patient presented with calf pain and soreness of the lower limb and the diagnosis was established with an elevated D-dimer level and CUS. We did not perform further test for PE as the patients showed no clinical signs of any respiratory or cardiovascular diseases.
Treatment
The prophylactic measurements after surgical detorsion during pregnancy are early ambulation, anti-embolism stockings and intermittent pneumatic compression devices. It should be noted that the prophylactic measurements may not be able to prevent VTE. As in our case, VTE occurred although early ambulation and anti-embolism stockings were applied. Unfractionated heparin (UFH) and LMWH are both safe during pregnancy as neither will cross the placenta. However, administration of anticoagulants need careful considerations as heavy bleeding has been reported in 1.98% of pregnancies [13]. In clinical practice, LMWH is the drug of choice for it is relatively easy to use and doses not require tedious monitoring. Guideline from the Royal College of Obstetricians and Gynaecologists [14] suggests that thromboprophylactic doses for antenatal LMWH should be based on weight with the most frequently used LMWH being Enoxaparin, Dalteparin and Tinzaparin. LMWH is recommended in therapeutic doses once daily or twice daily in the management of acute VTE in pregnancy. Nevertheless, for pregnant women with PE or severe VTE, LMWH should be initiated with therapeutic doses twice daily [12]. In the current study, we started the treatment with therapeutic doses twice daily, and the complete resolution of emboli occurred in two weeks.