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Pressure Wire Evaluation of the Left Main Stem. Dr Phil MacCarthy Consultant Cardiologist King’s Cardiac Centre. Left Main 5+ at AA2007, Jan 24 th , 2007. No conflicts of interest. Assessment of critical LMS disease is sometimes easy…. A more common clinical scenario.
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Pressure Wire Evaluation of the Left Main Stem Dr Phil MacCarthy Consultant Cardiologist King’s Cardiac Centre Left Main 5+ at AA2007, Jan 24th, 2007.
How do you currently establish the haemodynamic importance of a LMS lesion? Surgery!
The angiogram is a 2D representation of a complex 3D structure Topol and Nissen, Circulation 1995
Correlation between LMS anatomy and physiology Jasti et al, Circulation 2004
54 patients with equivocal LMS stenosis – FFR>0.75 in 24 (medical), FFR<0.75in 30 (CABG) Bech et al Heart 2001; 86: 547
51 patients – 24 FFR>0.75 treated medically, 27 FFR<0.75 treated surgically Lindstaedt et al, Am Heart J 2006; 152: 156
Case 2 - Stable • Pressure-wire study LMS • FFR 0.88 – No significant step-up on hyperaemic pull-back • Proceed to PCI of RCA CTO….
5.5mm2 Case 2 - Unstable
Practical Tips • Intravenous, centrally administered adenosine • Guide catheter engagement/damping • Beware distal disease • Differing FFRs in the LAD and Cx
Intravenous Infusion of Adenosine 140 µg/kg/min Adenosine IV Femoral
Practical Tips • Intravenous, centrally administered adenosine • Guide catheter engagement/damping • Beware distal disease • Differing FFRs in the LAD and Cx
Guiding Catheter in Ostium = Stenosis 8F Area Stenosis 2.4 mm 3 mm 64% 7F 49 % 3 mm 2.1 mm 6F 36 % 3 mm 1.8 mm
Practical Tips • Intravenous, centrally administered adenosine • Guide catheter engagement/damping • Beware distal disease • Differing FFRs in the LAD and Cx
(Pa - Pw) (Pm - Pd) FFR(B)pred = Pa (Pm - Pw) Pa Pd - (Pm/Pa) Pw FFR(A)pred = A Pa - Pm + Pd -Pw Pm B Pd Pw=Coronary occlusive pressure De Bruyne et al, Circulation 2000
Practical Tips • Intravenous, centrally administered adenosine • Guide catheter engagement/damping • Beware distal disease • Differing FFRs in the LAD and Cx
FFR = 0.63 FFR = 0.90
Conclusions • Pressure wire assessment of the LMS is technically easy • Medical treatment when the FFR>0.75 seems safe • Use central, iv adenosine and disengage the guide catheter before measuring • Beware underestimating FFR with downstream disease