RISKS AND OUTCOME IN PATIENTS WITH ACUTE SUBDURAL HEMATOMAS UNDER ANTICOAGULANT TREATMENT WITH VITAMIN K ANTAGONISTS
Authors: Papacocea Toma , Florea Alina , Papacocea Serban 
Published: November 2024

In this study we tried to determine the existence of a link between the INR at admission of patients with acute subdural hematomas and their subsequent evolution, the risk of requiring decompressive surgery and the mortality rate. We thus formulate the following questions to be researched, in correlation with the objectives of the study:

Does anticoagulant treatment with VKA increase the risk of needing surgery in patients with acute SDH?
Are acute subdural hematomas larger in patients anticoagulated with VKA?
Is mortality in patients with acute subdural hematomas higher in the case of association with anticoagulant treatment

with VKA?

Material and Methods
Retrospective study.

Inclusion criteria:
Patients discharged from the “Neurosurgery” Department of the “Sf. Pantelimon” from Bucharest with the main diagnosis at discharge “Traumatic subdural hemorrhage”, identified in the ICD-10 system with code S06.5.

Exclusion criteria:
- Patients with other post-traumatic intracerebral injuries (lacerations, cerebral contusions, epidural hematomas) that required surgical treatment.
- Patients with severe polytrauma.
- Patients with severe thrombocytopenia (< 50000 platelets / mmc).
- Patients with increased INR due to other causes (hepatopathies, alcoholism, etc.).
- Patients with chronic subdural hematomas with rebleeding.

Thus, in the interval 01.01.2020 – 31.12.2023 (4 years), after applying the inclusion and exclusion criteria, we obtained a group of 294 patients who had an acute subdural hematoma as their main or secondary diagnosis. Of these, 130, representing 44.2%, underwent a surgical intervention to evacuate the hematoma through craniotomy. Mortality for the entire group was 36.7% (108 deaths). In the case of operated patients, the postoperative mortality was 47.7% (62 deaths out of 130 patients), and in that of conservatively treated patients the mortality from various causes was 28.1% (46 cases out of 164).

Having this general information, we began the analysis of the situation of patients who, at the time of the trauma, were under anticoagulant treatment with vitamin K antagonists (Thrombostop or Sintrom). We found 42 such patients, most of them on anticoagulant therapy for atrial fibrillation, but there were also a few cases of valve prostheses. Of these patients, 20 (47.6%) underwent decompression surgery by evacuation of acute HSD. By comparison, 110 patients without anticoagulant treatment out of 252 underwent surgery (43.6%). Only a small difference is observed, at the limit of statistical significance, between the 2 groups, which made us analyze this aspect in more detail. First, we observed the INR in all 42 patients under VKA treatment and found a surprising fact: only 20 patients (47.6%) had an altered INR. Of these, 11 (55%) were operated and 9 (45%) treated conservatively. If we compare these numbers with those of all patients with a normal INR (274 of which 119 were operated on, i.e. 43.4%) we will find a significant difference between the 2 groups, a fact that confirms the assumption that patients with a modified INR and HSD acute have a higher risk of requiring surgery to evacuate the hematoma. Going even further with this analysis, we tracked the indication for surgery in patients on anticoagulant treatment by hematoma size and Glasgow score. Thus, we found that 25 of the 42 (59.5%) anticoagulated patients had an indication for surgical treatment. If we look only at patients with altered INR (20), we find that 16 of them (80%) had a surgical indication. Where does this difference between the surgical indication and the actual number of operations come from? The explanation is simple: 5 patients in the anticoagulant group, all with modified INR (average INR in this group 3.33) and aged over 70 years, were in such a serious condition that they died before they could be operated on, either in the EU or in the ICU, during attempts to stabilize the coagulant balance.

At this point in the presentation, we can answer the first question of this study: “Does anticoagulant treatment with VKA increase the risk of requiring surgery in patients with acute SDH?” The answer is yes, provided the treatment is properly administered and changes the INR. If we nuance things a little, we will notice that there are 13 patients with an INR below 3 and 7 with an INR above 3. In the first group, the surgical indication was present in 10 out of 13 patients (76.9%) and in the second in 6 from 7 patients (85.7%), so we can conclude that the higher the INR, the more the subdural hematoma risks to become a surgical lesion.

We also analyzed the average thickness of the hematoma in the patients in the group receiving anticoagulant treatment and found a significant difference between the group of patients with normal INR (0.9 cm) and that of patients with modified INR (1.55 cm). And within this group we have a difference between patients with an INR below 3 (1.36 cm) and those with an INR above 3 (2.04 cm). Therefore, the answer to the question: “Are acute subdural hematomas larger in patients anticoagulated with VKA?”, is clearly affirmative.

Next, we tried to highlight the causal relationship between the INR value at the time of trauma and the mortality rate. Thus, in patients with normal INR, the overall mortality was 33.9% (93 deaths out of 274 cases) and the postoperative mortality was 45.4% (54 deaths out of 119 cases). In those with modified INR, it was 70% (14 deaths out of 20 cases), respectively 63.6% (7 deaths out of 11 cases). Paradoxically, in patients with altered INR operated the mortality is lower than in non-operated ones (7 deaths out of 9 cases i.e. 77.7%), which would suggest that a more aggressive surgical approach could be beneficial in patients with acute subdural hematomas and anticoagulant treatment. Of the 7 patients with INR above 3, the only one who survived was an operated patient. Therefore, the answer to question 3: Is mortality in patients with acute subdural hematomas higher in the case of association with VKA treatment with modified INR? is also affirmative

Conclusions

Properly administered vitamin K anticoagulant treatment resulting in elevated INR increases the risk of patients with acute subdural hematomas, who will be more likely to require decompressive surgery, have larger hematomas, and have a higher mortality rate, regardless of therapeutic conduct.
In these patients, early surgical intervention, even if the INR has not been completely brought under control, is a therapeutic approach associated with a lower mortality than conservative treatment until the normalization of the INR.