The efficacy of percutaneous transluminal angioplasty (PTA) is usually
expressed as the angiographic result. Access flow (Qa) measurements offer
a means to quantify the functional effects. This study was performed to
evaluate the short-term functional and angiographic effects of PTA and to
determine the longevity of the functional effects during the follow-up
period. Patients with an arteriovenous graft (AVG) or an arteriovenous
fistula (AVF) who were eligible for PTA (Qa values of <600 ml/min) were
included. Ultrasound-dilution Qa measurements were obtained shortly before
PTA and periodically after PTA, beginning 1 wk after the procedure. The
short-term effects were expressed as the increase in Qa and the reduction
of stenosis. The long-term effects were expressed as patency and the
decrease in Qa after PTA. Ninety-eight PTA procedures for 60 patients (65
AVG and 33 AVF) were analyzed. Qa improved from 371 +/- 17 to 674 +/- 30
ml/min for AVG and from 304 +/- 24 to 638 +/- 51 ml/min for AVF (both P <
0.0001). In 66% (AVG) and 50% (AVF) of cases, Qa increased to levels of
>600 ml/min. The degree of stenosis decreased from 65 +/- 3 to 17 +/- 2%
for AVG and from 72 +/- 5 to 23 +/- 7% for AVF (both P < 0.005). The
reduction of stenosis was not correlated with DeltaQa (r(2) = 0.066).
Six-month unassisted patency rates after PTA were 25% for AVG and 50% for
AVF. The decreases in Qa were 3.7 +/- 0.8 ml/min per d for AVG and 1.8 +/-
0.9 ml/min per d for AVF. Qa values before PTA and DeltaQa were correlated
with the subsequent decrease in Qa (P < 0.005). In conclusion, Qa
increases after PTA but, in a substantial percentage of cases, not to
levels of >600 ml/min. Qa values before PTA and the increase in Qa were
correlated with long-term outcomes, whereas angiographic results were not.
These data, combined with literature data, suggest that there is optimal
timing for PTA
