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We read with interest Bellenger et als description of the
determination of fractional flow reserve (FFR) to guide treatment of side
branch arteries following provisional stenting across a bifurcation. The
use of pressure wires to guide treatment of main vessel narrowings (1) and
ambigious stenoses in multi-vessel disease (2) and ACS (3) is established.
Based on their preliminary findings, tha...
Based on their preliminary findings, that there is a poor correlation
between the angiographic degree of nipping by quantitative coronary
angiography (QCA) and the FFR in the side branches after stenting the main
vessel, the authors called for a randomised controlled trial to determine
whether FFR-directed treatment of side branch nipping improves clinical
and angiographic outcome following PCI at bifurcations.
Given that such side branches may be relatively small (2.3 +/-0.2mm
in the current study) we question the assertion that a QCA stenosis
>50% would trigger treatment by many interventionists. FFR
determination encompasses the interaction between the degree of anatomic
stenosis and the area of myocardium perfused by the vessel.
This goes some
way in accounting for the occurrence of haemodynamically significant
obstruction in only a minority of vessels (3/14) in the current study.
Indeed others have shown that in larger side branches (> 2.5mm) where
QCA-assessed stenosis is >75% following main vessel stenting, a greater
proportion will demonstrate functional significance (38% vs 27% in vessels
< 2.5mm), although the overall occurrence of functionally significant
stenoses remains small (4). Further, were treatment of the side branch to
be undertaken, it is as likely to involve POBA as a second stent procedure
(5). The authors own findings would suggest that a strategy of treating
only the main vessel is sufficient, achieving a "functionally adequate
result" in the majority of cases (79%). Therefore the extra cost incurred
by routine use of a pressure wire in this situation might prove difficult
to justify if, as the authors concur, the likelihood of a functionally
significant lesion is "infrequent". In their small pilot study, none of
the lesions measuring less than 50% by QCA were associated with a FFR less
Undoubtedly deferring treatment of side branches will prevent
unnecessary coronary interventions and their related complications -
whether routine use of a pressure wire is required to achieve this is
1. Bech GJW, De Bruyne B, Pijls NHJ, et al. Fractional Flow Reserve
to Determine the Appropriateness of Angioplasty in Moderate Coronary
Stenosis : A Randomized Trial. Circulation. 2001; 103(24):2928-2934.
2. Berger A, Botman K-J, MacCarthy PA, et al. Long-Term Clinical
Outcome After Fractional Flow Reserve-Guided Percutaneous Coronary
Intervention in Patients With Multivessel Disease.JACC. 2005; 46(3):438-442.
3. Joshua J. Fischer X.Outcome of patients with acute coronary
syndromes and moderate coronary lesions undergoing deferral of
revascularization based on fractional flow reserve assessment. Catheterization and Cardiovascular Interventions. 2006; 68(4):544-548.
4. Koo B-K, Kang H-J, Youn T-J, et al.Physiologic Assessment of
Jailed Side Branch Lesions Using Fractional Flow Reserve.JACC. 2005; 46(4):633-637.
5. Pan M, de Lezo JS, Medina A, et al.Rapamycin-eluting stents for
the treatment of bifurcated coronary lesions: A randomized comparison of a
simple versus complex strategy. Am Heart J. 2004; 148(5):857-864.