Normal coronary flow reserve after arterial switch operation for transposition of the great arteries: an intracoronary Doppler guidewire study.
BACKGROUND
Recent studies performed with positron emission tomography have suggested that coronary flow reserve (CFR) is moderately to severely reduced after the arterial switch operation (ASO). These findings are of great concern but have not been confirmed by other methods.


RESULTS
Eleven symptom-free children were studied between 4 and 11 (median 6.0) years after the ASO. Flow velocity in the left anterior descending (LAD) and right coronary arteries (RCA) was measured with a 0.014-inch Doppler FloWire (Cardiometrics) before and after intracoronary injection of adenosine (0.5 microg/kg) and nitroglycerin (5 microg/kg). CFR was defined as the ratio of hyperemic to basal average peak velocity (APV). The median (range) CFR in the LAD was 3.7 (3.0 to 4.8) and 3.4 (2.9 to 4.8) in the RCA. The increase in APV after intracoronary injection of nitroglycerin was 300% (240% to 420%) in the LAD and 260% (190% to 460%) in the RCA. APV at rest was 15.0 (14.0 to 21.0) cm/s in the LAD and 16.0 (9.6 to 30.0) cm/s in the RCA. A linear relation was found between right ventricular systolic pressure and resting APV in the RCA (r=0.77, P=0.0056), and between resting APV and CFR (r=-0.61, P<0.05) in the RCA.


CONCLUSIONS
The CFR and coronary vasoreactivity to nitroglycerin in children treated for transposition of the great arteries with the ASO was within normal limits. Increased right ventricular pressure and myocardial hypertrophy can cause increased resting coronary flow velocity in the RCA and affect CFR negatively.
Oskarsson
Gylfi
G
Department of Pediatric Cardiology, University Hospital of Lund, Sweden. oggylfi@hn.is
Pesonen
Erkki
E
Munkhammar
Peter
P
Sandström
Staffan
S
Jögi
Peeter
P
D000241:Adenosine / Q000494:pharmacology; D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology; D006328:Cardiac Catheterization; D002648:Child; D002675:Child, Preschool; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology; D003327:Coronary Disease / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000187:drug effects / Q000502:physiology; D004452:Echocardiography; D004562:Electrocardiography; D006801:Humans; D017078:Laser-Doppler Flowmetry; D016014:Linear Models; D005996:Nitroglycerin / Q000494:pharmacology; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D011666:Pulmonary Valve Stenosis / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D015899:Tomography, Emission-Computed, Single-Photon; D014188:Transposition of Great Vessels / Q000150:complications / Q000503:physiopathology / Q000601:surgery; D014665:Vasodilator Agents / Q000494:pharmacology; D014666:Vasomotor System / Q000187:drug effects / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D014665:Vasodilator Agents; C078700:technetium tc-99m tetrofosmin; D005996:Nitroglycerin; D000241:Adenosine