MRI and ce-mra in patients who have undergone a Fontan operation or a Bidirectional Cavo-Pulmonary Connection for Single Ventricle physiology R.Crepaz, J.Stuefer*, C.Romeo, C.Pedron **, O.Milanesi ^, G. Stellin^^ Divisione di Cardiologia-Servizio di Cardiologia Pediatrica Servizio di Radiodiagnostica - Risonanza Magnetica * Dipartimento di Pediatria TIN ** - Ospedale Regionale Bolzano Cardiologia Pediatrica ^, Cardiochirurgia Pediatrica^^ Dipartimento Pediatrico - Padova
Objectives Evaluate with MRI techniques and contrast-enhanced MRA (ce-mra) the morphology of the central vessels, the caval and pulmonary flows and differential pulmonary blood perfusion in patients whith TCPC or PCPC for single ventricle (SV) physiology. Basic anatomy of the study population Tricuspid atresia Pulm atresia + IVS Mitral atr+lvh-dorv+ps cctga + RVH HLHS Associated malformations TCPC n = 13 5* 1* 2** 1^ 4^ 5 PCPC n = 7 1 3 ^ ^ 3 ^ 2& * All previous PCPC (2 previous right BTshunt) ; ** 1 previous Kawashima ^ Previous Norw stages (1 unbalanced AVC with previous PAB > PCPC); ^ ^ 2 previous right BTshunt 1 TAPVR, 1 Subao st, 1 Heterotaxia (polisplenia), 2 Dextrocardia ; & 1 Heterotaxia (asplenia/polisplenia), 2 Dextrocardia,
Clinical characteristics of the study population age O2 Sat % RV/ LV type Age at repair (yrs) Type of repair Fenestration yes/no Follow up ( yrs ) Redo * PTA ** Collaterals embolization ^ TCPC n = 13 9,9 ± 4,2 (3-16) 93 ± 3 (88-97) 7 / 6 3,7 ± 1,9 3 Lateral Tunnel 10 Extrac.Conduit 7 /6 6,3 ± 4,4 1 3 3 PCPC n = 7 4,9 ± 3,8 (2-13) 82.5 ± 4 (77-88) 5 / 2 0,9 ± 0,6 4 BDG 1 Bilat BDG 2 Kawashima 4 ± 3,5 2 1 * Stenosis of BDG ** PA branch stenosis ( 1 stent/rpa +1 stent /SVC, 1 stent/lpa ) ^ Coils embolization of aorta-pulmonary (4) and veno-venous collaterals (1 ) ^^ Therapy in TCPC / PCPC : Bosentan / Sildenafil ( 4/2), ACEi ( 8/5), diuretics (1/1), Warfarin (5/0), aspirin (8/4)
Methods Clinical + Echo-Doppler follow-up Cardiovascular Magnetic Resonance (CMR) SV function + late gadolinium enhancement Morphology of lateral and extracardiac tunnels, cavo-pulmonary anastomoses, RPA, LPA, aorta and sistemic-pulmonary collaterals (ce-mra + Cine) Flow patterns and quantification in different segments of the Fontan circulation by PC-MRI to obtain: Total caval flow = IVC + RSVC + LSVC and IVC % Total pulmonary flow = RPA + LPA and RPA% Aortic flow Flow dynamics and differential pulmonary blood perfusion by time-resolved cemra (contrast agent injected into arm and leg veins)
VG 2.5yrs DORV-TGA+PS-LV hypopl S/P bilateral BDG + PA bifurcation/patch Severe stenosis at the level of PA bifurcation/patch
Flow measurements by Phase contrast-mri TCPC Extracardiac conduit NORMAL FLOW measurements of RPA and LPA distal to anastomosis AORTO-PULMONARY COLLATERALS quantification by comparing flows between pulmonary veins and arteries
Reduced caval and pulmonary vessels pulsatiliy in TCPC Pulsatility index (PI) = (max Flow rate min Flow rate)/mean Flow rate PI = 0,8 PI = 0,8 PI = 1,1 PI =0,6 TCPC Extracardiac conduit - 10yrs PI = 1,6 PI = 0,9 PI = 3,5 PI = 3,9 Normal 8 yrs
Caval and Pulmonary Artery flows in TCPC and PCPC age O2 Sat % Total caval flow (ml/min/m2) IVC flow % Pulmonary flow (ml/min/m2) RPA flow % Aortic flow (ml/min/m2) Pulm / Caval flow Caval / Aortic flow Pulm/ Aortic flow TCPC * n = 13 9,9 ± 4,2 (3-16) 93 ± 3 (88-97) 2370 ± 689 57 ± 12 1860 ± 443 47 ± 12 2870 ± 723 0,81 ± 0,15 0,85 ± 0,23 0,70 ± 0,24 PCPC^ n = 7 4,9 ± 3,8 (2-13) 82.5 ± 4 (77-88) 2265 ± 346 42 ± 14 1643 ± 692 58 ± 17 3460 ± 1030 0,56 ± 0,06 0,76 ± 0,21 0,46 ± 0,15 * Fenestrations ( 7/13) Systemic-Pulmonary (3) and veno-venous collaterals (1) ^ Systemic-Pulmonary (3) and veno-venous collaterals (1)
Caval and Pulmonary Artery flows in fenestrated vs non-fenestrated TCPC Fenestrated n = 7 Non fenestrated n = 6 P value age 10,4 ± 2,9 9,3 ± 5,7 O2 Sat % 91 ± 3 (88-95) 95 ± 2 (92 97) < 0.05 Total caval flow (ml/min/m2) 2637 ± 617 2035 ± 700 ns IVC flow % 55 ± 9 58 ± 15 ns Pulmonary flow (ml/min/m2) 1809 ± 432 1900 ± 561 ns RPA flow % 41 ± 14 52 ± 7 ns Aortic flow (ml/min/m2) 3283 ± 637 2355 ± 460 < 0.05 Pulm / Caval flow 0,69 ± 0,09 0,95 ± 0,06 < 0.01 Caval / Aortic flow 0,81 ± 0,16 0,89 ± 0,28 < 0.05 Pulm/ Aortic flow 0,60 ± 0,15 0,88 ± 0,28 < 0.01 Systemic-pulmonary (3 fenestrated -1 non fenestrated) and veno-venous collaterals (1 fenestrated)
GJ 9yrs PA+IVS - S/P rbtshunt and PTA of RPA - S/P fenestr TCPC/LT Mild RPA stenosis - Systemic-pulmonary collateral for right lung RPL 35 % Quantification of RL collaterals by comparing flows of RPA with right PVs
Time-resolved ce-mra with CM injected in right arm and leg Simmetric pulmonary perfusion
DP 14yrs Left Isomerism/polisplenia-single RV with double outlet and mitral atresia - S/P bilateral BDG at 9mths S/P TCPC (extracardiac conduit with hepatic veins connection at 2yrs) Total caval flow by PC-MRI by summing flows: -RSVC -LSVC -Azigos -Conduit (hepatiic veins)
Conclusions Caval and pulmonary flow patterns and quantification as well as morphology of the central vessels and anastomoses can be adequately assessed in pts with TCPC or PCPC by PC-MRI and CE-MRA and these data are useful for planing eventual interventional procedures Time-resolved CE-MRA can also depict the flow dynamics of the entire Fontan circulation as well as the lung perfusion status. After TCPC there is usually an asymmetric flow of the venae cave into the lungs No radioactive or contrast agent needed for MRI, thus reducing the overall radiation exposure of these pts who often require serial evaluations post surgical/interventional procedures
DP 13yrs S/P TCPC (Bicaval + Extracardiac tunnel) Flow measurements in the Fontan circulation by Phase contrast - MRI Rsvc 588 ml/min/m² Lsvc 539 ml/min/m² Rpa 1519 ml/min/m² Lpa 1029 ml/min/m² Livc 1470 ml/min/m² Conduit 490 ml/min/m²
GR 4yrs HLHS S/P Norwood 1.Stage (Sano)- S/P BDG at 6 mths severe RV dilatation and systolic dysfunction