Postoperative assessment of the univentricular repair by dynamic radionuclide studies.
BACKGROUND
The purpose of this investigation was to determine the role of radionuclide studies in evaluating postoperative Fontan hemodynamics and to quantify its diagnostic accuracy.


METHODS
One hundred five patients (105), aged 11 months to 35 years old, who had undergone univentricular repair, underwent first-pass and multigated acquisition scan 1 month to 10 years after univentricular repair. Forty-five patients with evidence of Fontan failure underwent radionuclide studies using Technetium-99 m as well as cardiac catheterization (group 1). The remaining sixty randomly selected patients with excellent functional status received radionuclide studies alone (group 2). The receiver operating characteristic curve analysis was done to quantify the diagnostic accuracy of the first-pass study.


RESULTS
There was paradoxical filling of the right lung after femoral injection in all cases of tunnel or conduit obstruction. A first-pass transit time of 16 to 25 seconds (mean +/- standard deviation [SD] = 18.82 +/- 2.69) was always associated with Fontan failure and high right atrial pressure (range = 20 to 24 mm Hg, mean +/- SD = 22.02 +/- 1.58). A first-pass transit time of 16 seconds was associated with a sensitivity of 100% and a specificity of 93.33%. The predictive accuracy of a positive or negative result was 91.8% and 100% respectively. The area measured under the receiver operating characteristic curve indicates that 99.41% (SE +/- 0.0035) of the time, the value of first-pass time is higher for the Fontan failure group (group 1) compared to the normal group (group 2; p = 0.000).


CONCLUSIONS
Our data indicate that Fontan circuit can be reliably evaluated for both anatomic and functional flaws by radionuclide studies; radionuclide first-pass time may be used to predict the chances of Fontan failure postoperatively as well as its presence; and in the presence of atrial fibrillation with fast ventricular rate, analysis using first-pass radionuclide may be impossible and gated equilibrium radionuclide angiocardiography may be the preferred method. Inspection of the systemic ventricular time-activity curve is of crucial importance in this regard.
Department of Cardiothoracic, Cardiothoracic Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi-110 029, India. ujjwalchow@rediffmail.com
Ujjwal K
UK
Chowdhury
Pankaj K
PK
Mishra
Rajesh
R
Sharma
Balram
B
Airan
Ganapathy K
GK
Subramaniam
Shyam S
SS
Kothari
Anil
A
Bhan
Chetan D
CD
Patel
Panangipalli
P
Venugopal
D000293:Adolescent; D000328:Adult; D006328:Cardiac Catheterization; D002648:Child; D002675:Child, Preschool; D004562:Electrocardiography; D018729:Fontan Procedure; D006352:Heart Ventricles / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006439:Hemodynamics; D006801:Humans; D007223:Infant; D008168:Lung / Q000000981:diagnostic imaging; D011183:Postoperative Complications / Q000503:physiopathology; D011184:Postoperative Period; D011237:Predictive Value of Tests; D011651:Pulmonary Artery / Q000473:pathology; D011652:Pulmonary Circulation; D012372:ROC Curve; D011877:Radionuclide Imaging; D012680:Sensitivity and Specificity; D013318:Stroke Volume; D013617:Tachycardia, Supraventricular / Q000503:physiopathology; D014655:Vascular Resistance