European guidelines on peri-operative venous... : European Journal of Anaesthesiology | EJA (2024)

Rationale and updated recommendations

Venous thromboembolism (VTE) is a rare but potentially fatal event for women during pregnancy and postpartum: in a national retrospective cohort of 1 235 149 caesarean deliveries in the United States, VTE incidence was 2.1 per 1000 deliveries at 330 days following delivery (95% confidence interval: 2.0 to 2.2).¹

1. Recommendation to implement a personalised evaluation of VTE risk factors as a safety tool for preventing mortality due to VTE:

In a national observational cohort during pregnancy and postpartum, a high proportion of the observed VTE-induced maternal mortality seemed potentially preventable; High-risk patient detection and treatment were not implemented.²

Throughout pregnancy and the postpartum period, the VTE risk assessment is based on the clinical and epidemiological evaluation of patient's risk.³ It should be evaluated through multidisciplinary scores.³ These scores should take into account personal and family history of thrombosis, clinical conditions such as bed rest or obesity, and pregnancy-induced diseases such as preeclampsia and postpartum haemorrhage, regardless of the mode of delivery.³ Each obstetric unit should adapt the scores to its own epidemiology and identify a systematic detection program for patients at risk. In cases of surgery during pregnancy and postpartum, the VTE risk inherent to surgery is added or combined to the identified individual patient risks.

In this context, we recommend that all pregnant women benefit from a personalised evaluation of VTE risk factors to be updated and, wherever possible, upgraded in surgery cases. An update should be performed during the postpartum period.

2. Recommendation of no changes to the previous ESAIC guidelines on caesarean section:

• (1) Thromboprophylaxis is recommended after caesarean section in all cases, except elective caesarean section in low-risk patients (Grade 1C), but there is no clear consensus on the definition of this population.
• (2) The duration of thromboprophylaxis following caesarean section should be at least 6 weeks for high-risk patients, and at least 7 days for the other patients requiring anticoagulation (Grade 1C).

3. Nonobstetric surgery during pregnancy and the early postpartum period:

No original articles or case reports were published during the review period (2018 to 2023). Even in international and national guidelines, non-obstetric surgery was not identified as a specific condition because of the rarity of the event.

We, therefore, recommend that there are no changes to the 2018 experts’ guidelines; thromboprophylaxis is broadly recommended because of the combined risk of surgery and pregnancy or postpartum period, regardless of the mode of delivery. We recommend prophylaxis following surgery during pregnancy or the postpartum period when they imply, as a consequence, bed rest until full mobility is recovered. (Grade 1C)

4. Pharmacology and therapeutic for preventing VTE in women undergoing surgery during pregnancy or postpartum:

Two recent randomised studies have been published concerning the adaptation of heparin doses in women during pregnancy and postpartum and may modulate the previous guidelines.

In a first randomised controlled trial (RCT), 74 women for which thromboprophylaxis was indicated after caesarean section, were randomised to two groups: in the fixed low molecular weight heparin (LMWH) dose group, patients received 40 mg daily for those with BMI less than 40 kg m⁻², or 40 mg every 12 h if BMI at least 40 kg m⁻². In the weight-based LMWH dose group, anticoagulation was calculated as 0.5 mg kg⁻¹ every 12 h. Those who received weight-based dosing were more likely to achieve prophylactic anti-Xa levels than those who received fixed dosing in primary analysis; 49/74 (66%) vs. 32/72 (44%), RR 1.49, 95% confidence interval (CI), 1.10 to 2.02 and secondary analysis; 49/60 (82%) vs. 32/57 (56%), RR 1.45, 95% CI, 1.12 to 1.88, respectively. There were no VTE events in either group.⁴

In a second RCT, out of 1110 women with a history of VTE receiving either LMWH weight-adjusted intermediate-dose or fixed low-dose from first trimester to 6 weeks postpartum. VTE occurred in 11 (2%) of 555 women and 16 (3%) of 555; [relative risk (RR) 0.69 (95% CI, 0.32 to 1.47); P = 0.33, with similar incidence of haemorrhagic complications.⁵

Thus, the experts recommend prophylactic postpartum LMWH dosage adjustment to patient weight when BMI is greater than 40 kg m⁻² and suggest that weight-adjusted intermediate dosing or a fixed low dose of LMWH are equipotent to decrease VTE incidence in pregnant and postpartum in patients with a history of VTE.⁵

5. Compression stockings:

There are no trials studying compression stocking effect on VTE incidence during and after surgery during pregnancy. Compression stockings and left lateral tilt are current practices during surgery in pregnant women to provide haemodynamic stability and avoid vasoplegia and pooling of blood in the lower limbs. In a meta-analysis of 12 studies involving 787 patients, compression stockings significantly reduced the incidence of hypotension during caesarean section versus no compression (RR 0.45, 95% CI, 0.32 to 0.62, I2 = 81%).⁶ Leg compression stockings also reduced maternal nausea and vasopressor requirement and increased maternal comfort, whatever the mode of anaesthesia used.⁷

Thus, the experts state on the clinical practice of compression stocking use for surgery during pregnancy.

Recommendations

• To decrease maternal mortality due to VTE, we recommend education of all patients on the symptoms and signs of VTE and to perform a personalised evaluation of VTE risk factors in all pregnant women, updated before any surgery (Grade 1C). We recommend an update in the postpartum period regardless of the mode of delivery (Grade 1C).
• When thromboprophylaxis is necessary, we suggest adjusting LMWH dosing to weight in women presenting with a BMI greater than 40 kg m⁻² (Grade 2C).
• In women with a personal history of VTE for surgery during pregnancy and postpartum, we recommend thromboprophylaxis with either a low dose or an intermediate dose of LMWH (Grade 2B).
• Compression stockings can be used during and after any surgery in pregnant or postpartum women, at least until ambulation. Although there is no evidence that compression stockings prevent peri-operative VTE, their use for surgery during pregnancy and the postpartum period might increase patients’ comfort and offset the effects of pregnancy-induced vasoplegia.

Acknowledgements relating to this article

Assistance with the article: none.

Financial support and sponsorship: the work was funded by ESAIC, EACTAIC, EACTS, ISTH, EURAPS and EKS.

Conflict of interests: none.

Presentation: none.

This article was reviewed by ESAIC members and approved by ESAIC Board.

This manuscript was handled by Jacky Nizard and Anne-Sophie Bouthors.

References

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