Plethysmographic Assessment of Jugular Venous Pulse in Jugular Venous Stenosis

Idiopathic intracranial hypertension (IIH) is a neurological disorder characterized by elevated intracranial pressure in the absence of an identifiable underlying cause. Symptoms: persistent headache, a sensation of cranial fullness, blurred vision, and occasionally, progressive vision loss. Identifying the subset of IIH patients whose condition is related to primary internal jugular
vein (IJV) obstruction which can be caused by: external compression by muscles or bones ⟶ angio-CT/MR1,2 intraluminal obstacles (webs, septa, or malformed valves) Methods This technology was originally developed in collaboration with the Italian Space Agency (ASI) and NASA to monitor cerebral venous return in microgravity conditions aboard the International Space Station. The jugular venous pulse (JVP) consists of three ascending and two descending waves per heartbeat, corresponding to cardiac phases. The distance between positive peaks (a, c, v) and negative troughs (x, y) represents the pressure gradient that facilitates cardiac filling from jugular veins [4]. Two cases of suspected IIH were investigated using a cervical plethysmographic (PG) sensor. In both patients, the PG signal exhibited abnormal JVP traces indicative of elevated venous pressure (Figure 2A). Doppler Ultrasound revealed immobile valve leaflets bilaterally, confirmed by catheter venography demonstrating bilateral narrowing of the IJV valve segments, with a pressure gradient of 6 cmH₂O compared to the superior vena cava. Both patients underwent balloon angioplasty without stenting, as the short, horizontal intraluminal obstacles were considered suitable for this approach [5]. The PG sensor generates data measured in nanoFarads (nF), synchronized with the ECG. The PG signal was processed using a Fourier transform filter with cut-off frequencies of 0.5–6.5 Hz to suppress low- and high-frequency noise. Subsequently, an algorithm identified key waveform peaks (a, c, v as maxima; b, x, y as minima). For each detected heartbeat,
differences ax, cx, and bx were calculated and averaged relative to the cardiac cycle, expressed as a percentage. Postoperative PG traces (Figure 1, red trace) demonstrated significant reductions in the v peak and x and y troughs. Although absolute PG values vary depending on acquisition conditions, within-cycle differences (ax, cx, bx) before and after surgery appeared
significantlly increased. This study demonstrates the effectiveness of a novel, non-invasive plethysmographic method for detecting pathological jugular venous pressure associated with IJV obstruction. Balloon angioplasty successfully normalized venous return in two patients with suspected IIH and confirmed IJV stenosis, as evidenced by significant changes in
plethysmographic parameters ax, cx, and bx. This method represents a promising diagnostic tool for selecting patients eligible for endovascular treatment.