Original Title: Utilizing Post-Intervention Fractional Flow Reserve to Optimize Acute Results and the Relationship to Long-Term Outcomes
Reference: Shiv K. Agarwal et al. J Am Coll Cardiol Intv. 2016;9(10):1022-1031.
Courtesy of Dr. Agustín Vecchia.
At present, fractional flow reserve (FFR) has become the gold standard to define ischemia in intermediate lesions, and to guide its management. Post PCI assessment of lesions continues to depend almost completely on angiographic appearance and partly on other intravascular images such as IVUS and OCT.
In these last years, new studies have suggested that incorporating functional analyzis of treated lesions has prognostic value and, in addition, could help functional optimization. The latest guidelines and consensuses have not stated anything on the matter.
The aim of the present study was to assess positive FFR after successful PCI, post intervention management and prognostic value of FFR at long term (one year) in this context. It included 574 consecutive patients (664 lesions) from the Arkansas healthcare system between January 2009 and September 2014. Patients had pre and post FFR. Primary end point was MACE (a combination of death, MI unrelated to procedure and target vessel revascularization). Follow up was 31 ± 16 months.
Results
- PCI was associated to significant improvement of FFR values from 0.65 ± 0.14 to 0.87 ± 0.08 (p < 0.0001).
- After PCI, 143 lesions with satisfactory angiographic appearance (21%) had positive FFR (FFR ≤ 0.81).
- After further interventions, FFR increased from 0.78 ± 0.08 to 0.87 ± 0.06 (p < 0.0001) in these lesions.
- A final FFR of 0.86 was the cutoff value that best predicted MACE (FFR ≤0.85 was a predictor of repeat revascularization).
- Patients with FFR ≥ 0.86 had significantly lower MACE than the group with FFR lower than cutoff value (17% vs. 23%; log-rank p = 0.02).
- A final FFR ≤ 0.86 had incremental prognostic value over clinical and angiographic variables for MACE prediction.
Conclusion
The authors concluded that through FFR we can reclassified 20% of angiographically satisfactory lesions requiring further intervention, which in turn improved patient prognosis.
Editorial Comment
Even though FFR has already shown prognostic value, at present there are no recommendations as regards its prognostic value post PCI. Johnson and collaborators published in this magazine in 2014 a meta-analyzis of nearly 9000 patients where the authors concluded that the use of FFR after PCI had inverse gradient with a risk of events.
The mechanisms underlying positive FFR after PCI are four: unmasking a second lesion, residual diffuse disease, pressure sensor drift or suboptimal stent deployment.
One of the limitations to this analyzis is that is does not specify which of this mechanisms is actually responsible. The importance of this information lies on two main factors:
- The greatest benefit of post PCI management may be unmasking new lesions, not post dilation, since in prior analyzes (ILUMIEN 1 trial) post dilation has not shown important benefits as regards improved FFR; that is, it would be interesting to analyze benefits according to the mechanism underlying positive FFR.
- Explaining the cause of FFR + could have helped determine the specific value associated to prognosis that most probably is no other than diffuse residual disease.
To conclude, the use of FFR post PCI depends on the lesion treated. In focal lesions, its benefit may be meagre but for bifurcations or sequential lesions, we can rely on this useful tool. In diffuse disease, the use of FFR is mainly prognostic and could eventually help justify residual symptoms or positive functional tests.
Courtesy of Dr. Agustín Vecchia. German Hospital, Buenos Aires, Argentina.
