Balloon angioplasty and stent implantation frequently resulted in impaired coronary flow reserve (33% and 58%, respectively) due to high baseline flow velocity, which normalized at 6 months.
Observational (n=54)
Does balloon angioplasty or stent implantation affect immediate and long-term coronary blood flow velocity reserve in patients with 1-vessel disease?
Impaired coronary flow reserve is common immediately after balloon angioplasty or stenting due to elevated baseline flow velocity, but normalizes by 6 months in the absence of restenosis, indicating delayed recovery of microvascular autoregulation.
Absolute Event Rate: 33% vs 58%
Background —There is controversy regarding the immediate and long-term effects of PTCA on the coronary flow reserve. Methods and Results —A total of 54 patients with 1-vessel disease and normal left ventricular function were studied after balloon angioplasty (n=34) or stent implantation (n=20). Distal coronary blood flow velocity reserve (CFR) was defined as the ratio of adenosine-induced hyperemic versus baseline blood flow velocity with a 0.014-in Doppler guidewire. The relative CFR was defined as the ratio of the distal CFR and the reference CFR measured in the normal adjacent coronary artery. Hemodynamic and angiographic measurements were performed before and directly after balloon angioplasty or stent implantation and at 6-month follow-up. CFR after PTCA ≤2.5 was defined as an impaired CFR. Immediately after PTCA, CFR improved toward the range of the reference artery CFR. In both the balloon-treated and the stent-treated groups, initial high CFR values decreased and impaired CFR values increased at follow-up toward the values of the reference CFR in patients without restenosis. Impaired CFR after balloon angioplasty (33%) or stent implantation (58%) in patients without restenosis was related to an increased baseline flow velocity that normalized at follow-up. Patients with an increase of CFR after stenting were characterized by an unaltered baseline flow velocity and an increased adenosine-induced hyperemic flow velocity. Conclusions —An impaired CFR (≤2.5) is a frequent finding after balloon angioplasty or stent implantation as a result of a high baseline flow velocity. Normalization of impaired CFR at follow-up in patients without restenosis was associated with a decline of the baseline flow velocity after both balloon angioplasty and stent implantation, supporting the contention that this phenomenon relates to a slow recovery of autoregulation of the microvascular bed.
Liebergen et al. (1998) conducted an observational in 1-vessel coronary artery disease (n=54). Balloon angioplasty vs. Stent implantation was evaluated on Impaired coronary blood flow velocity reserve (≤2.5) in patients without restenosis. Balloon angioplasty and stent implantation frequently resulted in impaired coronary flow reserve (33% and 58%, respectively) due to high baseline flow velocity, which normalized at 6 months.