“Acquired” Subvalvular Aortic Stenosis after Repair of a Ventricular Septal Defect

"Acquired" Subvalvular Aortic Stenosis after Repair of a Ventricular Septal Defect* Maria Paola Cicini , M.D.; Salvatore Giannico, M.D.; Bruno .'\Jarino, M.D.; Fiore S. Iorio, M.D.; Antonio Como, M.D.; and Carlo Marcelletti, M.D.

Of 353 children who underwent surgical repair of a congenital heart defect, including closure of a ventricular septal defect (VSD), 12 patients (four with tetralogy of Fallot, five with a VSD, and three with a double-outlet right ventricle) developed subaortic stenosis, which was diagnosed one to six years after the surgical procedure. Five patients required surgical treatment of the subaortic

aortic stenosis (SAS) has been reported Subvalvular to constitute 10 percent of all forms ofleft ventricular outflow tract obstruction, 1 and it is frequently associated with other congenital heart defects, including ventricular septa) defect (VSD), patent ductus arteriosus, tetralogy of Fallot , and coarctation of the aorta. 2 ·5 In the great majority of pediatric patients previously described, SAS was diagnosed with a measured left ventricular-aortic gradient and progressed to more severe obstruction. 1·6 In a few reported cases, SAS developed after early cardiac catheterization and echocardiographic examination had documented the absence of left ventricular outflow tract obstruction. 1.1>-9 Therefore, the development of SAS, at least in a subgroup of patients, seems to be an "acquired" disease with progressive hemodynamic severity. w· 11 Although the development of SAS after surgical repair of several congenital heart defects has been described, 12 • 15 there are few data about the relative incidence of postsurgical SAS. The purpose of this report is to describe the development and the relative incidence of SAS after suq~ical correction of several congenital heart defects in patients who had no subaortic obstruction at echocardiography or cardiac catheterization before surgery.

stenosis, and one required percutaneous balloon angioplasty. Postsurgical subaortic stenosis appears to be an uncommon progressive acquired disease. (Chest 1992; 101:115-18) DORY= double-outlet right ventricle; SAS= suhvalvular aortic stenosis; VSD =ventricular septal defect

patients, the surgical procedures included the closure of a VSD; 153 children had an isolated VSD , 186 also had tetraloJ.,'Y of Fallot , and 14 also had a dmrble-outle t right ventricle (DORV) (Table I). \Ve excluded from the study patients with unreliable echocardiographic or hemodynamic data. Pre- and postoperative two-dimensional echocardiographic examinations were performed with Hewlett-Packard (Andover, Mass) equipment, with 2.5- , 3 .5-, or 5.0-Mllz transducers. The same standard sulx.•>stal, parasternal , apical, and supraste rnal views were used (Fig I) in pre- and postoperative examinations. The studies were reL•>rdt'd on videotape and Wt're independently rt'viewt'd by two of the authors (M.P.C., S.G .). All patients included in this study underwt'nt preoperativt' right and left cardiac catheterization. Left ve ntricular angiography was performed by using standard ante roposterior and lateral projections and le ft anterior oblique views or elongated axial projections (Fig 2). Tht' diagnosis of :K'l''ire
PATIENTS AND METHODS

Subvalvular aortic stenosis has been defined as a membrane or fibromuscular ring encircling the left ventricular outffow tract immediate ly below the aortic valve. The L"ndition has been L•>nsidered acquired when it has not been diagnosed or even suspected at the time of initial cardiac catheterization or echocardiographic evaluation or during the intraoperative inspection. We reviewed the surgical, echocardiographic, and cardiac catheterization reports of353 selected patients who unde rwt'nt surgical repair betwet'n June 1982 and March 1990 in our institution. In all

*From tht' Department of Pediatric CardioloJ.,'Y and Cardiac Surgery, Bambino Geslr Hospital, Rome (Drs. Cicini, Giannk.i, Marino, Iorio, and Marcelletti); and the Department of Cardiothoracic Surgt'ry, lstituto Scientifim San Raffaele , Milan, Italy (Dr. Como).

F1c:t'HE I. Sulx..istal long-:Lxis echocardiographic ,·ie w obtained after n •pair of tetraloJ.,'Y of Fallot shows narrowing of the left \'entricular outffow tract due to a fihromuscular ridgt• and/or acc:t~

s sory

tnitral tisstw. CHEST I 101 I 1 I JANUARY. 1992

115

F1cn1t: 2 . Elongated long-axis dew from l1·ft n·11tric11lar angiogram shows SAS aft t'r DOR\. n•pair. Narrowing Sl't'lllS to ht• elm• to the ll'ft wntrirnlar i11fu11dil111lar fold appoS<•d to fibrous tissut' around tlw pateh . Contrast material shunts in the right n ·ntride through a small n•e11rn ·11t \ 'SD.

F1ll angioplasty. Suhvalvular narrowing set'ms to he rt'duce d (tilt' l.. ft Vt'nlricularaorlit· prt'ssurt' gradit•nt fall from fiO lo 30 nun Ilg).

sizt• was hast•d 011 the criteria for , ·ah-11lar aortic slt'nosis (Fig 3)."

flanges. One patient with DORV underwent successful percutaneous halloo11 angioplasty, which more than halved the left ventricular-aortic gradient (Table 2).

HESl l l.TS

We identified 12 patients (four with tetralo1-.ry of Fallot [2 . 1 percent of 186 patients], five with a VSD [3.2 percent of 153 patients], and three with DORV [21 .4 percent of 14 patients]) with acquired postsurgical suhaortic obstrnctio11 (fable I) in whom an SAS was diagnosed one to six yt'ars (median , three years) after surgical repair (fable 2). In ni11t' of these patients SAS was l'aUst'd by a fihrnm11sl'11lar ridge and/or acl't' ssory 111itral tissue: in thret' patients with DORv: it ,,·as l'a11s1·d by a left vt'ntril'ular infundihular fold apposed to fibrous tissnt' annmd the patch . Six patients had a lt'ft ,·e11tril'11lar-aortil' peak systolic gradient of less than 40 111111 Ilg without appeara11l'e of aortil' rt•g11rgitatio11. Six patit'11ts had a left ve11tricular-aortil' pt'ak systolic gradient of·m mm Hg or more with modt'ra!P aortic regmgitatio11 (Fig 4). Four of these six patie11ts u11dt•1we11t surgical resectio11 of a sull\·ah-ular mt•mhrane , aud one patient with DOHV u 11denn·11 t reseet ion of bilateral hu lhm·en t ric11 lar Tahle 1-0crnrrence of Posts11rgical SAS

<:011g1·11ital ( :011ditio11*

!'lio. of l'ati1·11ts \\'ho l'11dt•1we11I Ht·pair

!'lio. of l'alit·nts with l'oslsnrgieal SAS( % )

(2. ll

TF

ISH

.t

\'SD

l!l:3

.5 n.2)

l.t

:l (21.t )

DOIW

*TF = lt'lralogy of Fallot.

116

D1scuss10N The development and incidence of SAS after surgical repair of se\·eral congenital heart defects were documented in this series of patients. Although the small 1111mher of patients does not allow definitive condusio11s, postsurgical SAS seems to lw an uncommon l'Olllplil'atio11 in patients with VSD and tt'lralogy of Fallot (3 .2 percent aml 2.1 pt>rce11t. n•spedi\'ely) hut to he rt'latiw·ly mon• fr<'quent in patients with DOHV (21.4 perl't>nt). A possiblt• cause of this diAereJl(:e can he found in tlw different morphologic features: in patit>nts with DOHV the left ventricular infull(lihular fold more frequently induces a suhaortic narrowing apposed to fihrous tissue around the patch. It is conceivable that , in the presence of a VS D, the hemodynamic diagnosis of a suhaortic obstruction (peak-to-peak catheterization gradient or instantaneous echo-Doppler gradient) might he difficult. 2 ·1x The VSD may decompress the left ventricle and minimize any pressure gradient, and at angiocardiography the

< < 6 patients with LV-Ao<40mmHg

Morphologit· ft'alures Fihromuscular ridge an
12 patients with SAS

5 patients underwent resection

6 patients with

LV-Ao ~40

mm Hg

1 patient underwent PBA

F1t:l 'llE 4. 011tmmt• in 12 palil'nls with SAS. Tlw six patit'nls with a leli vt'nlricular-aortie pt·ak systolic gradient (LV-Ao) of )pss than 40 mm I lg had no l'Vidl'lll't' of aortic rt·gurgitation. PBA = percutaneous halloon angioplasty. "Acquired " Subvalvular Aortic Stenosis (Cicini et al)

Table 2-Coune of lbtienta with Pomurgical SAS* SAS Diagnosis SAS Treatment Patient 1 2 3 4 5

6 7 8 9 10 11 12

Date of Birth 01181 12183 05/81 03/82 10/89 03/81 11184 ()2187 08/85 02/83 10/82 10/84

Diagnosis VSD VSD VSD

05/81 0118.5 11182

TF VSD

()2184

DORY

TF TF VSD DORY DORY

TF

Date

Modality

LV-Ao, mmHg

03/87 12186 09/86 06/86 10/89

E2D Cath E2D Cath E2D E2D E2D Cath E2D Cath Cath E2D

45 100 50 70 30 15 30 25 25 60 40 15

Date of Repair

W87 09/81 04/86 06/89 09/87 11184 11183 08/86

07186 03/90

10/89 03/90 02J88

10/85

07/90

Date

Modality

05/87 01187 04/88 09/86

Resection Resection Resection Resection

07188

PBA(20) Resection

11185

*LV-Ao =left ventricul~aortic peak systolic gradient; E2D =two-dimensional echocardiography; Cath = catheterization; TF = tetralogy of Fallot; PBA =percutaneous balloon angioplasty (value in parentheses is LV-Ao after treatment).

contrast material shunted through the VSD may mask the presence of a membrane in the left ventricular outflow tract. Thus, the obstruction may become hemodynamically relevant and unmasked only after closure of the VSD. Therefore, the diagnosis of subaortic obstruction is usually made on the basis of morphologic data obtained at two-dimensional echocardiography rather than on the basis of the hemodynamic gradient. However, in all of our cases, there was no evidence of obstruction at the angiographic, twodimensional echocardiographic, and Doppler examinations obtained before surgical closure of the VSD. The finding of significant SAS some years after surgery in all of these patients suggests that trivial or mild obstructions tend to progress. The etiology and pathogenesis of SAS are still incompletely understood. A possible mechanism can be found in the hemodynamic changes due to surgical repair. However, there are still some unresolved questions: Is the development of the subaortic obstruction in congenital heart defects an acquired, progressive, independent process? Is the surgical closure of VSD a determinant or just an accelerating factor? In conclusion, we believe that discrete SAS is an uncommon late complication of surgical repair of several congenital heart defects, including VSD closure, and that it is an acquired condition with progressive hemodynamic severity. Recent studies and our experience suggest that this malformation requires surgical treatment or percutaneous balloon angioplasty. •s-22 ACKNOWLEDGMENTS: The authors are grateful to Maria Giulia Galdiardi, M.D., and Alessandro Giamberti, M.D., for the revision of the clinical data; to Mrs Maria Lina Riva for technical assistance; and to Miss Orietta Castellacci for the editing of the manuscript. REFERENCES 1 Newfeld EA, Muster AJ, Paul MH, Idrin FS, Riker WL.

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3

4 5

6

7 8

9

10

11

12

13

14

15

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Plan to Attend ACCP's

58th Annual Scientific Assembly f'Ulf'A~n Chicago ~ October 25-29, 1992

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"Acqulrad" SUbvalvular Aor1lc Stenoala (Clclnl et al}