Patient/prosthesis mismatch: how to evaluate and when to act? Svend Aakhus, MD, PhD Oslo University Hospital, Norway Disclosures: No conflict of interest
Types of aortic valve prostheses (AVR) Mechanical single disk Mechanical bi-leaflet AVR Stented bio-prosthesis Stentless bio-prosthesis
Definition of patient/prosthesis mismatch, PPM Valve orifice area inadequate in a patient despite normal function of the prosthesis Pibarot P and Dumesnil JG. JACC 2000;36:1131
mean AVR gradient (mmhg) Classification of PPM Severe PPM: EOAi < 0.65 cm 2 /m 2 rest Moderate PPM: 0.65 EOAi 0.85 cm 2 /m 2 No PPM: EOAi > 0.85 cm 2 /m 2 peak exercise Pibarot P and Dumesnil JG. JACC 2000;36:1131
Prevalence of AVR PPM Severe (EOAi<0.65 cm 2 /m 2 ): 2% Moderate (EOAi 0.65-0.85 cm 2 /m 2 ): 31% Normal (EOAi>0.85 cm 2 /m 2 ): 67% Mohty D et al. JACC 2009;53:39
Patient example F 73 yrs St. Jude 19, NYHA II Vmax 3.6 m/s MG 24 mmhg EOA 1.1 cm 2 AVR dysfunction? JG290337 5 yrs later: NYHA II Vmax 3.8 m/s MG 31 mmhg EOA 0.9 cm 2
Causes of increased AVR gradient Patient-prosthesis mismatch (PPM) Gorlin equation Pressure recovery ΔP = [ CO ] k. A 2 Increased flow Obstruction LVOT AVR malfunction AVR gradient relates to: Transvalvular flow Effective orifice area
Determinants of AVR gradient AVR bioprosthesis In vitro study Dumesnil JG and Yoganathan AP. Eur J Cardiothorac Surg 1992;6:34
Evaluation of AVR AVR maximal blood flow velocity AVR mean gradient AVR Doppler acceleration time/ velocity profile Doppler velocity index (DVI) Effective orifice area (EOA) Fluoroscopy
AVR, Doppler flow Maximal blood flow velocity, Vmax AV Mean gradient, MG ΔP =4 v 2 Acceleration time, AT Doppler velocity index, DVI: CW AVR VTI AV MG Vmax AV PW LVOT DVI Vmax = Vmax LVOT Vmax AV VTI LVOT Vmax LVOT AT DVI VTI = VTI LVOT VTI AV
AVR effective orifice area, EOA Doppler LVOT LVOT CSA Doppler AVR PW Doppler LVOT VTI LVOT Continuity equation, EOA: EOA = CSA LVOT x VTI LVOT VTI AV CSA LVOT = π(d/2) 2 CW Doppler AVR VTI AV EOAi = EOA/BSA (cm 2 /m 2 )
LVOT diameter in AVR LVOTd Ao AML HEA270759
AVR, fluoroscopy Knowledge of: Prosthesis characteristics Leaflet opening angle HSG261166
AVR prosthesis function Echo parameters: Normal Significant stenosis Peak velocity, m/s <3 >4 Mean gradient, mmhg <20 >35 AT, ms <80 >100 CW jet contour Triangular Rounded DVI 0.30 <0.25 EOA, cm 2 >1.2 <0.8 Adapted from: Zoghbi WA et al JASE 2009;22:975
Causes of increased AVR gradient JG290337 F 73 yrs St. Jude 19, NYHA II Vmax 3.6 m/s MG 24 mmhg AT 72 ms DVI VTI 0.34 EOAi 0.7 cm 2 /m 2 - PPM 5 yrs later: NYHA II Vmax 3.8 m/s MG 31 mmhg AT 65 ms DVI VTI 0.32 EOAi 0.6 cm 2 /m 2 Severe PPM?
Expect PPM in patients with: Larger BSA Smaller LVOT diameters Native aortic valve stenosis Older age (>70 years) Calcified aortic annulus
Consequences of PPM Increased AVR gradient Increased LV work Sustained LV hypertrophy Clinical symptoms Increased mortality and morbidity
PPM: 30-days relative mortality risk Blais C et al. Circulation 2003;108:983
PPM and long-term prognosis severe PPM moderate PPM Mohty D et al. JACC 2009;53:39
Other causes of increased AVR gradient - pressure recovery phenomenon Bileaflet prostheses, central high velocity jet EOA corrected for pressure recovery Energy loss coefficient: E L Co = EOA x Ao A Ao A - EOA Bach DS JACC CV img 2010;3:296 Small asc. aorta diameter ( 3.0 cm)
Other causes of increased AVR gradient - increased flow M 51 yrs CM23, NYHA III Vmax 3.7 m/s MG 32 mmhg DVI VTI 0.36 EOAi 0.6 cm 2 /m 2 AT 97 ms Severe paravalvular AR HEA270759
Other causes of increased AVR gradient - obstruction, AVR malfunction F 38 yrs Mosaic 23, NYHA II Vmax 3.7 m/s MG 33 mmhg DVI VTI 0.27 EOAi 0.6 cm 2 /m 2 AT 120 ms Significant bio-prosthesis stenosis AEB160471
Characteristics of PPM induced high AVR gradient Smaller AVR and/or larger BSA High gradient early after AVR Sustained gradients over years Normal DVI and AT EOA within reference range Normal fluoroscopy
Prevention of PPM problems Pre-operative Identify LVOT/BSA discrepancy Identify reduced LV function Select AVR prosthesis: Ideally EOA > 0.9 cm 2 x BSA Per-operative Maximize AVR EOA If PPM is likely: consider stentless bioprosthesis, aortic root enlargement, xeno- or homografts Post-operative Early baseline echocardiography
When to re-operate in AVR PPM Severe PPM (EOAi < 0.65 cm 2 /m 2 ) Significant daily life symptoms Dyspnea/fatigue Anginous chest pain Syncope Technical availability Risk vs. benefit consideration
In summary, PPM Is prevalent after AVR Impairs symptomatic improvement and survival after AVR May be prevented by pre- and peroperative considerations Re-op. indicated in selected patients
Reasons for over-estimating PPM High flow situation Febrilia, anemia, hyperthyroidism, etc Pressure recovery Small ascending aortic diameter (<3.0 cm) Central jet in bileaflet AVR Technical Contamination of AVR signal by MR signal Erroneous overtracing of Doppler signal Angle correction of Doppler
Reasons for underestimating PPM Low-flow situation Technical: Angle deviation > 20 degrees
Systematic evaluation of elevated AVR gradient Zoghbi WA et al JASE 2009;22:975
Bach D JACC img 2010