Patients with end-stage renal disease (ESRD) often require arteriovenous grafts (AVG) for hemodialysis. AVG thrombosis is a common complication, usually managed by percutaneous transluminal angioplasty (PTA) to restore blood flow. PTA achieves patency by balloon-mediated compression and fragmentation of thrombus. Small thrombus fragments may enter the venous circulation and cause transient pulmonary microembolism, leading to ventilation-perfusion (V/Q) mismatch. This study uses electrical impedance tomography (EIT) to noninvasively monitor short-term changes in regional ventilation and perfusion during and after PTA, exploring the immediate pulmonary physiological consequences of thrombus fragmentation and revascularization in dialysis patients.

Arteriovenous graft (AVG) thrombosis is a major source of vascular access failure in ESRD. PTA restores patency through balloon dilation and mechanical thrombus compression. Minor embolic debris can reach the pulmonary bed, transiently disturbing perfusion distribution and V/Q matching. Because the pulmonary circulation is sensitive to sudden peripheral hemodynamic shifts, the PTA period provides a unique opportunity to observe lung perfusion response dynamically.

This single-center, prospective, observational pilot study will continuously record regional ventilation and perfusion by EIT at six time points: 10 min before PTA, at recanalization, and 10, 20, 30 min after, and at procedure completion. Measured variables include: V/Q matching index (primary), physiological dead space fraction (Vd/Vt), intrapulmonary shunt fraction, SPO₂/FiO₂ ratio, and hemodynamic data (balloon pressure, recanalization time, blood flow recovery). Results will be analyzed using repeated-measures ANOVA or mixed-effects modeling.

Inclusion Criteria

1. Age ≥ 18 years.
2. Diagnosis of end-stage renal disease receiving maintenance hemodialysis.
3. Documented AVG thrombosis requiring PTA.
4. Able to cooperate and tolerate EIT monitoring.
5. Provided written informed consent.

Exclusion Criteria

1. Severe respiratory failure incompatible with supine position.
2. Thoracic skin condition or deformity preventing EIT electrode placement.
3. Acute pulmonary embolism or acute pulmonary edema before procedure.
4. NYHA Class IV heart failure or hemodynamic instability.
5. Pregnancy or breastfeeding.
6. Any other circumstance judged unsuitable by investigator.

Patients with end-stage renal disease (ESRD) undergoing maintenance hemodialysis who present with thrombosed arteriovenous grafts (AVG) requiring clinically indicated percutaneous transluminal angioplasty (PTA) to restore patency. The study population will consist of adult patients (18-80 years) admitted to the interventional radiology or dialysis access unit of the First Affiliated Hospital of Wannan Medical College (Yijishan Hospital). All participants will receive routine PTA treatment as part of standard care. EIT monitoring will be applied non-invasively to collect ventilation and perfusion signals before and after PTA. No additional interventions beyond routine clinical management will be introduced.