Rivaroxaban versus low-molecular weight heparin prior to scheduled Ultrasound evaluatioN in patients with suspected Deep Vein Thrombosis

In patients with deep vein thrombosis (DVT) of the lower extremity, urgent diagnostics and treatment are needed. During the time between clinical suspicion and definite ultrasound diagnosis patients go untreated, with risk for embolization of the thrombus, which could lead to severe morbidity and even death. In almost all hospitals, patients with suspected DVT are therefore referred to the emergency department for further diagnostics and treatment. However, this system poses a large burden on health care services, very often resulting in overtime work by physicians and several hours of waiting time for the patients. Therefore, Zuyderland MC uses a more directive approach (to the best of our knowledge as the only hospital in the Netherlands), by performing DVT diagnostics during a scheduled appointment at a specialized DVT clinic the next day, instead of referring patients to the emergency department. In order to prevent embolization of the DVT, all patients receive one dose of an anticoagulant from their general practitioner, awaiting further testing. This transition from emergency care to elective care for patients suspected for DVT has several potential benefits: reducing peak load in emergency departments, reducing waiting times, improving patients and physicians’ satisfaction, and enabling deployment of dedicated care givers specialized in thrombosis instead of general emergency department staff. However, ‘real world’ data on these benefits are lacking, hampering the implementation of such system in other hospitals. Therefore, the first goal of this study is to evaluate these potential benefits, including patients’ and physicians’ satisfaction by means of questionnaires.

Secondly, the preferred type of anticoagulant drug will be evaluated. Currently, Zuyderland Medical Centre uses low-molecular weight heparin (LMWH) as the preferred type of pre-emptive anticoagulation. However, as LMWHs have to be dosed on body weight, have to be stored under controlled circumstances, and have to be administrated parenterally which requires some training, this results in several logistic disadvantages. Therefore, general practitioners asked Zuyderland Medical Centre to explore alternative approaches such as the use of direct oral anticoagulants (DOACs) instead of LMWHs as this could take away many of these inconveniences: all patients can use the same dose, patients can take the pill without help, and the general practitioner could keep a small stock at his/her practice which make urgent pharmacy visits no longer necessary.
Current guidelines support the use of DOACs in case diagnostic studies are deferred and from a pharmacokinetic/dynamic point of view there are no reasons to believe that DOACs are inferior to LMWH. Therefore, in 2021 the regional protocol will be changed from LMWH to DOAC as the preferred type of pre-emptive anticoagulation. However, in our opinion studies on the use of DOACs in this setting are scarce and evidence on potential benefits such as patients’ and physicians satisfaction of DOACs over LMWH are lacking. Therefore, we will evaluate the change in protocol from LMWH to DOAC in a regular clinical setting of pre-emptive anticoagulation (even though guidelines support the use of DOACs in this setting), in order to provide ‘real world data’ and to evaluate if all assumptions on potential benefits including patients’ and physicians’ satisfaction are true.

Primary:
1) Prospective evaluation of scheduled/elective care for patients suspected for DVT in terms of patients’ and physicians satisfaction (PROMs and PREMs) and waiting hours for the patients.
2) To evaluate whether oral administration of rivaroxaban would be preferred over the currently used injection of dalteparin in terms of patients’ and physicians satisfaction, non-major bleedings and cost-effectiveness.
Secondary:
3) To evaluate whether this approach is also feasible for patients with active malignancy.
4) To explore if PROMS, either alone or in combination with standard laboratory tests (D-dimer, complete blood count, C-reactive protein etc.), may help in differentiating between different causes of a swollen leg (such as deep vein thrombosis, bacterial infection, ruptured Baker’s cyst, venous insufficiency etc.).

- Clinically relevant bleeding within 72 hours after administration of anticoagulant drug (definitions see secondary outcome section).
- Symptomatic pulmonary embolism within 72 hours after administration of anticoagulant drug, requiring evaluation by a physician or hospital admission.

Questionnaires