Significance of hemodynamic assessment by pressure wire for endovascular therapy of subclavian steal syndrome.

OBJECTIVE: Subclavian steal syndrome results from hemodynamic impairment due to stenosis or occlusion of subclavian artery. Therefore, it is important for subclavian steal syndrome patients to assess hemodynamic status during endovascular therapy.
METHODS: Eleven subclavian steal syndrome patients undergoing endovascular therapy attended this study. Pressure wire was used to measure trans-stenosis pressure difference (ΔP). Digital subtraction angiography, Transcranial Doppler and Electronic sphygmomanometer were introduced to assess stenotic rate, steal grade and inter-arm systolic pressure difference, respectively. Clinical symptoms and restenosis were followed up after endovascular therapy. The associations of ΔP with stenotic rate, inter-arm pressure difference, steal degree, clinic symptoms and restenosis were analyzed in this paper.
RESULTS: Prior to the therapy, ΔP moderately correlated with stenotic rate (r = 0.757, p = 0.007) and inter-arm pressure difference (r = 0.701, p = 0.016). ΔP was ≥6 mmHg in all patients, and 6-9 mmHg for grade 1 steal and ≥10 mmHg for grade 2 and 3 steals. After the therapy, all patients had technique success, and 10 patients had clinic success, and 1 patient appeared restenosis. ΔP was ≤3 mmHg and steal disappeared in the patients with clinical success. ΔP was 18 mmHg and grade 3 steal still existed in one patient without clinical success. One patient with 1 mmHg of ΔP after therapy appeared restenosis in the follow-up.
CONCLUSION: The trans-stenosis pressure difference is closely related to steal degree and clinical symptoms. The measurement of hemodynamic status by pressure wire is very useful to guide endovascular therapy in subclavian steal syndrome patients. However, the restenosis may still occur, even though the hemodynamic impairment is improved.