Concordance between venous sinus pressure and intracranial pressure in patients investigated for idiopathic intracranial hypertension

Abstract

Background: Idiopathic intracranial hypertension (IIH) is a cause of chronic headaches that are probably driven by raised intracranial pressure (ICP). Cerebral venous sinus pressure is thought to play a role in the underlying pathology, but its relation with intracranial pressure requires further investigation. We aimed to evaluate the concordance between lumbar puncture opening pressure (LPOP) as indicator of the ICP and cerebral venous sinus pressure in patients investigated for IIH.

Methods: In this case-series replication study, all patients with IIH suspicion and who underwent cerebral venous sinus pressure measurement followed immediately by LP opening pressure (LPOP) measurement were retrospectively included. Pearson's correlation and measurement agreement (Bland-Altman plots) between venous pressure and LPOP were analyzed.

Results: 52 consecutive patients (46 women; median age, 31 years [IQR = 25-42]) were included. The mean pressure in the superior sagittal sinus (SSS) and in the torcular were 20.9mmHg (SD ± 7.3) and 20.8 mmHg (SD ± 6.8), respectively. The mean LPOP was 22mmHg (SD ± 6.4). Pressure measured in the transverse venous sinus, the torcular, and the SSS correlated with LPOP (p < 0.001). Bland-Altman plots showed that torcular pressure strongly agreed with LPOP (mean difference of 1.7mmHg). The limit of agreement (LOA) (mean difference ± 1.96SD) contained 98.1% of the differences between the two methods, confirming the concordance between the two measures. Torcular pressure and LPOP were consistent in patients with a trans-stenotic pressure gradient ≥ or < to 8 mmHg (mean difference: 1mmHg and 2.4mmHg, respectively), and for those with a LP OP ≥ or < to 18mmHg (mean difference: 1.8mmHg and 1.95mmHg, respectively).

Conclusions: In patients investigated for IIH, the ICP measured at the LP is correlated and concordant with the torcular pressure. These results confirm previous findings and further corroborate the hypothesis that cerebral venous system plays a major role in CSF dynamics and ICP.

Keywords: Concordance; Idiopathic intracranial hypertension; Lumbar puncture; Transverse venous sinus stenosis.

Fig. 1

(A-B). Patient position during cerebral venous pressure measurement (A): the transducer is zeroed to atmospheric pressure and is placed at the level of the left external meatus. Patient position during lumbar puncture opening pressure measurement (B): the pressure transducer is placed on the mid-sagittal line with the patient in left lateral decubitus

Fig. 2

Study flow chart

Fig. 3

(A-B-C-D). Bland-Altman plots illustrating the agreement between the LPOP and cerebral venous pressure measured in the Superior Sagittal Sinus (A), Torcular (B), right (C) and left (D) Traverse Venous Sinus

Fig. 4

(A-B-C-D). Bland-Altman plots illustrating the agreement between the LPOP and pressure recorded in the torcular in the subgroups of patients with LPOP ≥ 18 mmHg (A) and < 18 mmHg (B), as well as in patients with a trans-stenotic pressure gradient ≥8 mmHg (C) and < 8 mmHg (D)