Читать книгу Interventional Cardiology - Группа авторов - Страница 197

Fractional flow reserve has been assessed after coronary intervention in a number of studies. Post‐PCI FFR values below 0.90 predict a less favorable clinical outcome in an early PCI era [31,89]. Some of the post‐PCI studies were in a period of balloon angioplasty with stenting only used for bailout [31]. Subsequent studies in the DES era have similarly demonstrated a higher event rate in those patients in whom post‐PCI FFR is not optimal; there is consistent evidence for increased rates of target vessel failure and target vessel revascularization when FFR falls within lower tertiles or quartiles [25–27,29,32]. While individual studies do not have sufficient power to show higher rates of mortality and myocardial infarction, meta‐analysis has shown both are predicted by low FFR values post‐PCI [30,31]. Data collated from large randomized studies show the greatest clinical benefit is seen in patients with the largest gain in FFR [28]. Post‐PCI resting whole cycle Pd/Pa has also been shown to predict MACE events after intervention with values over 0.96 representing a more favorable result [90].

The frequency of an inadequate physiological result is more common than appreciated. Large studies have suggested that an FFR ≤0.80 can occur in 10–20% of cases suggesting a suboptimal interventional result [29,32].

A single focal stenosis without residual disease is expected to achieve a high post‐PCI FFR value. Those lesions with moderate or high burdens of residual disease, then lower post‐PCI FFR values are expected. However, the same limitations of angiography that exist prior to intervention, continue to impact assessment after PCI and can mean residual disease is under‐estimated. It is recommended that FFR is repeated after PCI and careful pullback measurement is made to assess the cause of residual pressure loss.

In some circumstances, the vessel remains ischemic and, in this setting, this can reflect: (i) the incorrect coronary stenosis has been targeted, (ii) there is an issue within the stented segment, or (iii) diffuse coronary atherosclerosis that was not amenable to treatment with a focal stent.