Dr. Wissem Sdiri
Prof. Antoine Lafont,
Angiographic data are sometimes insufficient to assess the severity of a given coronary stenosis. This is usually the case in intermediate stenosis for which interventional cardiologists have 2 questions : can this lesion induce myocardial ischemia ? and consequently, does it require angioplasty ?
Stress echocardiography and stress perfusion scintigraphy can answer these interrogations with accuracy. However, non invasive tests have 2 limitations : they can be inconclusive and some patients undergo a coronary angiogram before a non invasive evaluation.
Fractional flow reserve (FFR) is an index derived from coronary artery pressure measurements, providing functional data through a simple and safe procedure. It is defined as the ratio between the maximal blood flow to the myocardium in the presence of a stenosis in the supplying artery and the theoretical normal maximal blood flow in the same area in the absence of the stenosis. To induce maximal hyperemia, some drugs are available: Adenosine (intracoronary bolus or intravenous infusion), ATP (intracoronary bolus or intravenous infusion) or Papaverine (intracoronary bolus). Each drug is used with a specific dosage, which is validated in humans to induce maximal hyperemia. In our institution, we use intracoronary bolus’ of Adenosine (40µg in the left coronary artery – 20µg in the right coronary artery). Adenosine induces hyperemia by stimulating specific receptors, mainly A2 arteriolar receptors. Therefore, there is no need to stop medicines such as nitrates, beta-blockers or calcium blockers. Another interesting feature of FFR, is that it is independent of haemodynamic conditions (heart rate, blood pressure, and contractility). In practice, a pressure guide wire is placed distal to the stenosis giving a distal pressure (Pd). Aortic pressure (Pa) is measured as usually through the guiding catheter. FFR is calculated at maximal hyperemia by dividing mean distal pressure by mean aortic pressure.
FFR = Pd /Pa
A cut-off value of 0.75 has been established in correlation with non invasive tests, to distinguish stenoses that can induce ischemia from those that do not. So, FFR is considered as an online scintigraphy, providing accurate data concerning functional severity of intermediate stenosis even in acute coronary syndromes without ST-segment elevation. More recently, some studies suggest that FFR, is feasible in infarct-related coronary arteries providing data regarding both ischemia and viability. Another application for FFR, is the assessment of stent deployment; this interesting field is investigated in the current FROST 4 trial. Unfortunately, FFR is still expensive so its use is limited to only a few centres. In conclusion, FFR is an accurate index for functional evaluation of intermediate stenosis, it can avoid abusive revascularisation, it shortens the length of hospitalisation and renders the interventional cardiologist more autonomous in his decisions.
The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.
Bech GJW, De Bruyne B, Bonnier HJRM and al. Long-term follow-up of percutaneous transluminal coronary angioplasty of intermediate stenosis on the basis of coronary pressure measurement. J Am Coll Cardiol 1998;31:841-847. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=9525557
Bech GJW, De Bruyne B, Pijls NHJ and al. Fractional flow reserve to determine the appropriateness of angioplasty in moderate coronary stenosis. A randomi sed trial. Circulation 2001;103:2928-2934. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11413082
Chamuleau SAJ, Meuwissen M, Koch KT and al. Usefulness of fractional flow reserve for risk stratification of patients with multivessel coronary artery disease and intermediate stenosis. Am J Cardiol 2002;89:377-380. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11835914
Chamuleau SAJ, Meuwissen M, Van Eck-Smit BLF and al. Fractional flow reserve, absolute and relative coronary blood flow velocity in relation to the results of technetium-99m sestamibi single-photon emission computed tomography in patients with two-vessel coronary artery disease. J Am Coll Cardiol 2001;37:1316-1322. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11300441
De Bruyne B, Pijls NHJ, Bartunek J and al. Fractional flow resreve in patients with prior myocardial infarction. Circulation 2001;104:157-164. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11447079
Lessar M, Abdul-Baki T, Akkus N, Sharma A, Kannan T, Bolli R. Use of fractional flow reserve versus stress perfusion scintigraphy after unstable angina. J Am Coll Cardiol 2003;41:1115-1121. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12679210
Pijls NHJ, De Bruyne B, Peels K and al. Measurement of fractional flox reserve to assess the functional severity of coronary-artery stenoses. N Eng J Med 1996;334:1703-1708. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=8637515
Pijls NHJ, Klauss V, Siebert U and al. Coronary pressure measurement after stenting predicts adverse events at follow-up. A multicenter registry. Circulation 2002;105:2950-2954. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12081986
Dr Wissem SDIRI, Dr. Antoine LAFONT Hopital Européen Georges Pompidou Université PARIS V, France
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