RESULTS
Thirteen patients (81%) had situs solitus and 3 (19%) patients had
situs inversus. We encountered double inlet ventricles in 6 of the cases
(37%). Three patients had tricuspid and two patients had mitral
atresia. In thirteen out of 16 patients (81%), one of the ventricles
were hypoplastic, right ventricle in 7 and left ventricle in 6 cases. In
3 cases, both of the ventricles were developed and the indication for
Fontan palliation were congenitally corrected transposition of the great
arteries (c-TGA) (pt. no 5 and 9) and a criss-cross atrioventricular
(AV) connection in the setting of double outlet right ventricle (DORV)
and a large ventricular septal defect (VSD) (pt. no 6).
Stage-1 palliation was deemed necessary in 8 of the cases (50%). These
interventions included balloon atrial septostomy or surgical atrial
septectomy in order to increase mixing at the atrial level, pulmonary
banding in order to control pulmonary arterial pressure and flow and
modified Blalock-Taussig shunt (MBTS). Patient no. 6 had a history of
supramitral membrane resection along with pulmonary artery banding and
atrial septectomy. All of the surgical atrial septectomy procedures were
performed as concomitant interventions, none of the patients were
operated on for surgical atrial septectomy alone. Five patients (31%)
had a history of systemic to pulmonary shunt surgery as stage I
palliation (pt. no 4,5,8,13 and 14). In patient no.13, early
postoperative shunt occlusion was encountered and primary surgical
thrombectomy was performed. In all other cases, MBTS grafts were
primarily patent until surgical closure at the following stages.
Stage-2 palliation was performed in all cases which included superior
cavopulmonary anastomosis and concomitant procedures, which included
atrial septectomy, pulmonary banding, pulmonary artery patch
augmentation and atrioventricular valve repair. The bidirectional Glenn
procedure was bilateral in patients 10, 14 and 15. Prior shunts were
clipped or divided at stage II, except for two cases. In patient no.8,
MBTS was still functional as an additional pulmonary blood flow source
and in pt. no 5, there was an unintentional residual shunt flow at the
time of stage III. Both of these cases were operated on at other cardiac
surgery centers at stage II palliation and these shunts were closed at
stage III.
Stage III Fontan completion was achieved with apolytetrafluorethylene (PTFE) tubular conduit
(GORE-TEX, W.L. Gore and Associates Ltd., Livingston,
Scotland) at sizes between 16 mm and 22 mm. Extracardiac Fontan
procedure was performed in all cases, except for pt. no 11 and 14 where
an intra-extra cardiac conduit was interposed. Concomitant procedures at
stage III included DeVega tricuspid annuloplasty, pulmonary artery
reconstruction, atrial re-septectomy and shunt closure. Fenestration was
performed in 4 cases (25%) (pt. no 1,4,11 and 12). At the time of stage
III, all of the patients underwent preoperative cardiac catheterization
under local anesthesia and sedation. In pt. no7, a major aortopulmonary
collateral artery was occluded via femoral route before stage III
completion. We did not encounter any inferior vena cava interruption and
azygos vein continuity. The mean pulmonary artery (Nakata) index was
calculated as 293 ± 72 mm2/m2 (range
171 to 456 mm2/m2). Interstage
period, i.e. the time between stage II and stage III operations were 4 ±
2.6 years (range 1 to 10 years). The stages of Fontan circulation and
concomitant procedures are summarized in table-3.
The mean preoperative MPAP measured at the catheterization lab and at
the operation room were 17.5 ± 2.1 mmHg and 16.5 ± 1.8 mmHg,
respectively. The central venous pressure (measured via internal jugular
vein catheter) that was recorded at the initiation of Fontan completion
in the operation room represented the MPAP, since all the patients had a
prior cavopulmonary anastomosis. All of the patients had antegrade
pulmonary blood flow except for the patients no. 4 and 5 who had atresia
of the pulmonary valve. The antegrade pulmonary blood flow was
diminished either by native valvular or subvalvular pulmonary stenosis
and/or a pulmonary band placed at the time of bidirectional Glenn
procedure in 13 of the cases, except patient no. 10, who had a double
inlet left ventricle with restrictive VSD. The mean pulmonary arterial
gradient (except pt. no 4, 5 and 10) was 73.5 ± 10.2 mmHg (range 50 to
86 mmHg) at the time of Fontan operation. Postoperative MPAP and
arterial oxygen saturation levels were 11.2 ± 2.8 mmHg (range 4 to 15
mmHg) and 97.8 ± 2 (range 93 to 100), respectively. The preoperative and
postoperative MPAP values of the patients following the Fontan
completion are presented in figure-1.