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.
Study Type
OBSERVATIONAL
Enrollment
20
Non-invasive 16-electrode EIT belt applied at the 4th intercostal level. Continuous data acquisition begins 10 min pre-PTA, continues throughout balloon angioplasty, and up to 30 min post-recanalization. No alteration to standard clinical care.
The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital of Wannan Medical College)
Wuhu, China
RECRUITINGChange in Ventilation-Perfusion Matching Index
Quantitative index derived from EIT ventilation and perfusion maps, indicating spatial regional correlation of air and blood flow distribution.
Time frame: Baseline (10 min before PTA), immediate post-recanalization, 10, 20, 30 minutes, and procedure end.
Change in Peripheral Oxygen Saturation
Time frame: Baseline (10 min before PTA), immediate post-recanalization, 10, 20, 30 minutes, and procedure end.
Change in Physiological Dead Space Fraction
Ratio of physiologic dead space to tidal volume, calculated by EIT validated algorithm, reflecting inefficiency of ventilation.
Time frame: Baseline (10 min before PTA), immediate post-recanalization, 10, 20, 30 minutes, and procedure end.
Change in Intrapulmonary Shunt Fraction
Percentage of the lung region showing perfusion without ventilation, estimated from EIT perfusion signals.
Time frame: Baseline (10 min before PTA), immediate post-recanalization, 10, 20, 30 minutes, and procedure end.
Change in Regional Ventilation and Perfusion Distribution
Variation in spatial patterns of pulmonary ventilation and perfusion derived from pixel-based EIT data.
Time frame: Baseline (10 min before PTA), immediate post-recanalization, 10, 20, 30 minutes, and procedure end.
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