Direction value of endovascular pressure differences in endovascular management of subclavian steal syndrome

Objective To explore the direction value of endovascular pressure differences in endovascular management of subclavian steal syndrome (SSS). Methods Eleven SSS patients accepted endovascular management, admitted to our hospital from January 2016 to December 2017, were collected in this study. Before and after operation, pressure-sensing wire was used to measure endovascular pressure differences (mean distal stenosis pressure minus mean proximal pressure), digital substraction angiography (DSA) was used to assess the stenotic rate, transcranial doppler (TCD) was used to assess the steal degrees, and electronic sphygmomanometer was used to measure the systolic pressure differences between bilateral brachial arteries. The pressure differences before and after endovascular management were compared. Before operation, the relations of pressure differences with stenotic rate, steal degrees and systolic pressure differences between bilateral brachial arteries were analyzed. After operation, the relations of pressure differences with stealing and clinical symptom improvements were analyzed. The predictive values of pressure differences and residual stenosis in clinic success were compared. Results (1) After operation, the blood stealing disappeared and the clinical symptoms improved in 10 patients; although residual stenotic rate of one patient decreased obviously, blood stealing and clinical symptoms still existed after operation; the clinic success rate was 90.9%(10/11). (2) Pressure differences before surgery ([11.2±5.7] mmHg) were significantly higher as compared with those after the surgery ([2.5±5.3] mmHg, P<0.05). (3) Before operation, pressure differences were significantly correlated with stenotic rate (r=0.757, P=0.007) and bilateral systolic pressure differences (r=0.701, P=0.016). Six patients had pressure differences of 6-9 mmHg, enjoying degree I and II of stealing, and 5 patients had pressure differences≥10 mmHg, enjoying degree III of stealing. (4) After operation, pressure difference was 18 mmHg in one patient without clinic success, but pressure differences were≤3 mmHg in 10 patients with clinic success. (5) Significant difference was noted between the two clinic success indexes (residual stenotic rate≤30% by DSA and pressure differences≤3 mmHg, P<0.05). Conclusion Endovascular pressure differences can reflect the hemodynamic changes before and after endovascular management; as compared with residual stenosis, it is better to predict the clinic success after operation; it is useful to guide the endovascular management in the SSS patients. Key words: Subclavian steal syndrome; Endovascular treatment; Endovascular pressure difference; Pressure-sensing wire