Ventricular Outflow Tract Stenosis Research Articles

How to diminish reoperation rates after initial repair of tetralogy of Fallot?

Background. Complete correction of tetralogy of Fallot has good long-term results. Right ventricular outflow tract obstruction and pulmonary insufficiency occur which require reintervention. The present study evaluated the efficacy of reoperation following complete correction of tetralogy of Fallot, the sites of recurrences and impact of techniques used at first operation. Methods. Between 1980 and 1999, 501 patients underwent complete correction of tetralogy of Fallot. Reoperation rate was 7.4%. Residual or recurrent right ventricular outflow tract stenosis was seen in 25 patients (68%), and 7 patients (19%) had severe pulmonary insufficiency. Age at redo was 9.1 ± 6.4 years. Restenosis was most frequently observed (75%) at the bifurcation of the pulmonary artery. Extended 1-patch enlargement was used until 1989 and thereafter changed to a 2-patch technique. Results. Valvar-supravalvar 1-patch technique had a redo rate of 33.3%, compared with 4.3% for the 2-patch technique, p = 0.0264, with excellent freedom from reoperation rate. At reoperation right ventricular-pulmonary artery (RV-PA) conduits managed 29 patients and 3 had supravalvar patch enlargement. Hospital mortality was 5.4% (2 of 37). Twenty-five patients (68%) were in New York Heart Association functional class I to II at end of the follow-up, and none required further interventions. Conclusions. Redo rate following complete correction of tetralogy of Fallot was 7.4%. Right ventricular outflow tract pathology was the dominant reason for reoperations (86%). At reoperation, RV-PA conduits was the most frequently used technique. Reoperation was efficient in reducing the RV-PA gradient, had low hospital and late mortality. A 2-patch valvar-supravalvar enlargement at first operation reduced the risk for redo in long-term follow-up.

Results of the Lecompte procedure in malposition of the great arteries and pulmonary obstruction.

Assessment of the Lecompte procedure, our repair method of choice in malposition of the great arteries with pulmonary stenosis. A retrospective analysis of 42 patients (median age at operation, 1.4 years) operated on between 1986 and 1999 for various forms of great artery malposition, ventricular septal defect, and pulmonary stenosis. Relevant associated findings included the insertion of a tricuspid papillary muscle on the conal septum (nine patients), absence of conal septum (six patients), hypoplasia of a side pulmonary artery (four patients), and hypoplasia of the right ventricle (one patient). A preliminary systemico-pulmonary shunt was created in 28 patients and a cavo-pulmonary anastomosis in one patient. At operation, the conal septum (whenever present) was resected (36 patients), the pulmonary bifurcation was usually translocated over the ascending aorta (37 patients), and the main pulmonary artery was enlarged with a patch of pericardium. A monocusp valve was fashioned within the patch in 40 patients. The follow-up information was complete in 32 patients and ranged from 0.4 to 14 years (mean, 5.4+/-3.2 years). The survival rate at 5 years was 92+/-5%. Three patients died post-operatively (mortality, 7%) and none during follow-up. The freedom from reoperation was 86+/-8 and 51+/-22% at 5 and 10 years, respectively. Six patients were reoperated, all for a pulmonary stenosis. Calcification of the monocusp patch was present in all. Pulmonary stenosis developed in three further patients: one underwent percutaneous dilatation and two are awaiting surgery. No procedural factors thought to have a potential correlation with the development of right ventricular outflow tract stenosis could be individualized on univariate analysis. The Lecompte procedure, which allows early repair of these defects, provides overall good results. The need to reoperate on the right or left ventricular outflow tract seems reduced in comparison with the Rastelli operation, the other alternative.

Influence of Pulmonic Position on Durability of Bioprosthetic Heart Valves

Background. The insertion of bioprosthetic valves into the pulmonic position is not performed commonly because of uncertainty concerning the necessity and durability of such valves. Methods. We reviewed the long-term outcome of 10 patients who underwent pulmonary valve replacement with bioprostheses between March 1985 and March 1997. A Carpentier-Edwards supraannular bioprosthesis was used in 7 patients, a Hancock II bioprosthesis was used in 2 patients, and a Carpentier-Edwards pericardial bioprosthesis was used in 1 patient. The mean patient age at the time of pulmonary valve replacement was 38.9 ± 16.3 years (range, 15 to 63 years). The diagnoses were pulmonary valvular regurgitation after corrective surgery for tetralogy of Fallot in 7 patients, right ventricular outflow tract stenosis and absent right pulmonary artery combined with a double-outlet right ventricle in 1 patient, pulmonary valvular regurgitation with pulmonary artery dilatation in 1 patient, and aortic valve stenosis treated with our modification of the Ross procedure using a pulmonary bioprosthesis in 1 patient. Survivors were followed up for a mean of 5 years and 5 months. Results. One patient underwent reoperation because of infective endocarditis of the bioprosthesis. No bioprosthetic valve dysfunction has been observed on Doppler echocardiography during a maximum follow-up period of 12.2 years, except in the patient who underwent replacement at 15 years of age. Conclusions. Bioprostheses in the pulmonic position are durable in adult patients because they face a minimal hemodynamic load, but they may undergo early leaflet degeneration in younger patients.

Konno-aortoventriculoplasty with mechanical prosthesis in dealing with small aortic root: a good surgical option.

This study was undertaken to evaluate the effectiveness and the results with the Konno-aortoventriculoplasty. Over a 10-year period, 21 Konno-aortoventriculoplasties were performed in 20 patients utilizing mechanical cardiac valvular prostheses, in 14 male and 6 female patients for complex left ventricular outflow tract stenosis. The mean age was 9.2 years (range 1.7-25.7 years). The pre-enlargement mean aortic annular size was 11.5 mm (6-16 mm). The mean size of the prostheses implanted was 20.4 mm (19-23 mm). In a typical case, the aortic annulus was enlarged to twice its original size. The only operative death was in a 8 kg, 20-month old child with previous commissurotomy, due to intractable bleeding and low output state. The mean hospital stay was 9.4 days (1-15 days), and the mean ICU stay was 3.3 days (1-7 days). The only late death was in a patient who went on to have cardiac transplantation for progressive left ventricular dysfunction. The 10-year acturial survival was 90 +/- 7%, and the reoperation free survival was 89 +/- 7%. All of the 18 surviving patients are asymptomatic at the time of last clinic visit (mean follow-up of 61.1 +/- 31.7 months, range 0-139 months). All patients had resolutions of their left ventricular hypertrophy with insignificant gradient across the repair by echocardiography. Konno-aortoventriculoplasty is extremely effective in the treatment of small aortic annuli and complex left ventricular outflow tract obstruction. In the present era of increasing popularity of autograft and homograft operations, the Konno procedure should remain in the technical armamentarium of the cardiac surgeon.

Intra-arterial aortoinfundibuloplasty: hemodynamic and anatomical study of a new method for the enlargement of a small aortic annulus.

A new method for prosthetic valve replacement in a small aortic annulus is described. An anatomical examination showed that the intra-arterial approach via the main pulmonary artery made it feasible to incise the aortopulmonary septum at the middle point of both coronary ostia and also to relieve left ventricular outflow tract obstruction with a two-dimensional patch. The pressure study in three mongrel dogs demonstrated that 6-mm augmentation of the host aortic annulus with this procedure made no significant difference in the pressure gradient between the right ventricle and the main pulmonary artery before and after operation. The right ventricular end-diastolic pressure did not show any significant change with respect to hemodynamics. It is expected from these results that our procedure could be used for the treatment of various types of left ventricular outflow tract stenosis without affecting the hemodynamics and, especially, right ventricular function.

Magnetic Resonance Imaging of Cardiac Function and Morphology in Patients with Transposition of the Great Arteries Following Mustard Procedure

In order to assess the diagnostic possibilities of magnetic resonance imaging (MRI), 30 children (mean age 11.5 years) with d-transposition of the great arteries (TGA) corrected by the Mustard procedure were studied. Patient values were compared to those of 10 healthy volunteers. The most important postoperative abnormalities such as baffle leaks, systemic or pulmonary venous obstructions, left ventricular outflow tract (LVOT) stenosis and tricuspid regurgitation were assessed. Cardiac volumes and muscle mass were measured. Baffle leaks were found in 5 and obstruction of the baffle limbs in 6 patients. On gradient echo images 13 patients showed signs of LVOT stenosis and 12 tricuspid incompetence. Right ventricular end diastolic volumes in patients were significantly higher than the left ventricular volumes, but slightly lower than right ventricular volumes in the normals. In patients with TGA and ventricular septal defect (VSD) (n = 7) right ventricular (RV) volumes were found to be higher than in patients with intact ventricular septum (n = 23) and in normals. In contrast to the normal RV function of patients after Mustard surgery only patients with previous VSD showed a diminished RV ejection fraction. The muscular mass in TGA patients showed a ratio of 1.9:1 between right and left ventricles. In normals the ratio was 1:1.5. Magnetic resonance imaging allows a quantitative insight into the ventricular function and the morphology of the heart after inflow correction. Thus, it supplements the noninvasive evaluation of TGA patients.

Transoesophageal echocardiographic assessment of fixed subaortic obstruction in children.

To evaluate the clinical usefulness of transoesophageal echocardiography in the assessment of children with fixed left ventricular outflow tract stenosis. Eight consecutive children, aged over 5 years, with fixed subaortic stenosis and one child with fixed subpulmonary left ventricular outflow tract stenosis were prospectively assessed by precordial and transoesophageal echocardiography. Transoesophageal images of the left ventricular outflow tract were much clearer than precordial images in all patients except one with a prosthetic mitral valve. Improved visualisation provided further information on the nature of the lesion (additional chordal attachment of the mitral valve in one, accessory atrioventricular valve tissue with aneurysm formation in one), on the extent of the lesion (circumferential in three), and on the very close relation of a ridge to the aortic valve leaflets in one. Transoesophageal Doppler did not provide any additional information on aortic regurgitation and was unreliable for gradient estimation across the left ventricular outflow tract. Transoesophageal imaging provides an excellent means of visualising lesions in the left ventricular outflow tract and can be useful in a few children and adolescents in whom precordial echocardiography does not provide adequate information. The technique can also be used intraoperatively to define the full extent of the obstructive lesion and to assess residual lesions after surgery.

Anterolateral muscle bundle of the left ventricle in atrioventricular septal defect: Left ventricular outflow tract and subaortic stenosis

The anatomy of the left ventricular outflow tract (LVOT) in 77 hearts with atrioventricular septal defect (AVSD), 36 with a separate A V orifice and 41 with a common A V-orifice, were investigated. In all specimens, an anterolateral muscle bundle of the left ventricle was identified between the superior bridging leaflet and the left coronary aortic cusp. It displaced the attachment of the superior bridging leaflet, resulting in its clockwise rotation. The muscle bundle frequently bulged into the LVOT, but was never prominent enough to have caused significant subaortic stenosis. Measurement of the LVOT aortic ratio was possible in 54 hearts and ranged from 36-100%. In 23 cases (43%), there was mild to moderate subaortic narrowing with a ratio ranging from 53-88%. In six cases (11%), unequivocal subaortic stenosis was present, mainly in AVSD with separate A V orifices (five of six) and iatrogenic in one case with surgically corrected complete defect. A decreased ratio was mainly due to decreased anteroposterior width of the septum in the subaortic area, with anterior displacement of the superior bridging leaflet in cases with dense septal attachment of the superior bridging leaflet (i.e., in AVSD with separate A V orifices, type A complete defect with small ventricular septal defect, or surgically corrected complete defect). Significant subaortic stenosis was caused by hypertrophy of the ventricular septum in the subaortic area with anteroseptal twist in four cases, by anomalous chordal insertion of the superior bridging leaflet in one case, and iatrogenic in one case after surgical correction with left A V valve replacement in type C complete defect.(ABSTRACT TRUNCATED AT 250 WORDS)

Repair of complete atrioventricular septal defect with tetralogy of Fallot

Repair of complete atrioventricular canal with tetralogy of Fallot was performed in 9 patients. Ventricular septal defect was closed through the right atrium using a single polytehafluoroethylene patch with ample anterior extension to avoid subaortic obstruction. The atrial septal defect was closed with a separate patch. Undivided atrioventricular valve leaflets were sandwiched between the two patches. Right ventricular outflow tract stenosis was relieved by pulmonary valvotomy and an infundibular patch in 7, a supravalvar patch (none transannular) in 6, and right ventricle-to-pulmonary artery conduit in 2. There was one hospital death ( 1 / 9 , 11%) in a patient with persistent clinically significant postoperative pulmonary stenosis and low cardiac output requiring reoperation and right ventricle-to-pulmonary artery conduit insertion. There was no late mortality. All patients are asymptomatic 0.3 to 5.6 years after operation. Follow-up right ventricular outflow tract gradient ranged from 11 to 43 mm Hg and was 70 mm Hg in 1 patient who later had successful relief of obstruction. Three patients had mitral valve insufficiency; 1 needed reoperation. Aggressive relief of right ventricular outflow tract stenosis with maintenance of pulmonary valve competence and use of two separate patches for closure of the septal defects contribute to optimum immediate and long-term results after repair of this lesion.

Differences of Postextrasystolic Behavior of Left Ventricular and Aortic Pressures Between Fixed and Dynamic Left Ventricular Outflow Tract Stenosis

The dynamic behavior of fixed LV outflow tract stenosis partly resembles that of OCM. To analyze their differences we studied basal and postextrasystolic (post-PVC) peak-to-peak LV aortic gradients, aortic systolic pressure, and pulse pressure in 14 OCM and in 36 pure VAS without two-dimensional echocardiographic findings of OCM. Fifteen mild VAS had basal gradients similar to those of OCM (39 +/- 17 mm Hg vs 24 +/- 16 mm Hg). Patients with OCM show a post-PVC gradient (109 +/- 41 mm Hg) similar to that of VAS (110 +/- 50 mm Hg). However, the latter were departing from much higher gradients (VAS 72 +/- 30 mm Hg vs OCM 24 +/- 16 mm Hg). Decrement of post-PVC aortic systolic pressure and pulse pressure were frequent in both groups, but decrement of pulse pressure greater than 5 mm Hg were more frequent in OCM. We concluded that (1) post-PVC increased aortic gradients and decreased aortic systolic pressure occurred in both VAS and OCM; (2) post-PVC decreased aortic pulse pressure might occur in VAS; and (3) association of post-PVC gradient increment greater than 75 percent and pulse pressure decrement greater than 5 mm Hg are strongly suggestive of OCM.

An autopsy case of sudden unexpected death due to atherosclerotic coronary heart disease associated with simple right ventricular outflow tract stenosis

A case of a 35-year-old male who died suddenly after a blow on the chest by his opponent during a quarrel. From both the clinical and autoptical examinations there was no evidence of trauma found anywhere, even in the chest. The heart was the only one of all the internal organs whereon significant pathologic changes were observed during autopsy. It's lesions were as follows: (I) The right ventricle was greatly enlarged simply due to the simple right ventricular outflow tract stenosis (SRVOTS); the heart weight was 587 g. (II) All the main trunks of coronary arteries were involved by atheroslcerosis. In addition, the appearance of the lumen at the proximal end of the left anterior descending artery narrowed by an atheromatous plaque (grade II) was completely occluded by a newly formed thrombus. The authors believed that both the coronary atherosclerotic changes and the enlarged heart due to the SRVOTS played a role in the pathogenesis of death (Kelberlus, H.E. and Wellens, H.J.J., Sudden Death, Developments in Cardiovascular Medicine, Vol. 4, Martinys Nijhoff Publishers, London, 1980, pp. 34–48; Jinming, Qin, A study of cardiac sudden death (51 cases) on the clinical pathologic view, Tianjin Med., 8 (1980) 458–461). The quarrel and blow were the disposing factor.

Two-dimensional echocardiographic detection of pulmonary venous channel stenosis after Senning's operation.

Stenosis of the common pulmonary venous (PV) channel after Senning's operation for complete transposition of the great arteries is a serious problem, and a method for noninvasive diagnosis is highly desirable. Therefore, our purpose was to devise a method to diagnose PV channel stenosis noninvasively. The newly created common PV channels were measured and the short-axis views of the left ventricle were observed by means of two-dimensional echocardiography in 16 patients who had undergone Senning's procedure. In seven patients we used the original procedure and in nine patients we used a modified procedure with a pedicled pericardial patch. The shape of the left ventricle became round abruptly when the width of the PV channel decreased below a critical value (a range of 6 to 9 mm). Three patients with a relatively round-shaped left ventricle and a narrow PV channel (below 9 mm) were all confirmed to have PV channel stenosis at reoperation. All of the patients with a wide PV channel (above 10 mm) and a flat-shaped left ventricle were in good condition both clinically and as determined from the catheterization data. After the operation, patients who had tricuspid regurgitation, pulmonary vascular obstruction, or residual left ventricular outflow tract stenosis had a relatively round-shaped left ventricle even though the PV channel was wide enough (above 10 mm). Measurement of the PV channel confirmed the effects of these conditions. Correct diagnosis of PV channel stenosis can therefore be made by observing the shape of the left ventricle and by measuring the PV channel.

M-mode echocardiographic assessment of D-transposition of the great arteries and associated defects.

M-mode echocardiographic, hemodynamic, and angiographic correlations are presented for 97 patients with d-transposition of the great arteries. Forty-one patients were studied before and 73 patients after the Mustard operation; 17 patients were studied sequentially before and after the Mustard operation. The echocardiographic diagnosis of d-transposition could be made with high accuracy by using two criteria: (1) opening of the posterior semilunar valve earlier than the anterior semilunar valve, and (2) location of the anterior semilunar valve to the right of the posterior semilunar valve with transducer angulation toward the right shoulder. In the pre-Mustard group the presence of associated lesions such as patent ductus arteriosus and ventricular septal defect was suggested by an elevated left ventricular end-diastolic/right ventricular end-diastolic dimension ratio (>1.2). In the post-Mustard group, after correction of shunting lesions, this ratio was similar to that in patients with intact ventricular septum. In pre-Mustard patients the anatomically fixed type of left ventricular outflow tract stenosis was suggested by a left ventricular outflow tract/pulmonary artery ratio of less than 0.5. This ratio was 0.52±0.1 in those in whom resection of the anatomic stenosis and Mustard operation were performed. Right ventricular function could be assessed by the pre-ejection period/right ventricular ejection time ratio; a ratio of greater than 0.5 was associated with angiographically determined ejection fraction of 0.5 or less.

Surgical treatment of various types of left ventricular outflow tract stenosis by aortoventriculoplasty--clinical results.

Since 1974 the new concept of aortoventriculoplasty (AVP) has been applied clinically in Göttingen. Out of 1,112 patients with various types of congenital aortic stenosis 502 patients have undergone commissurotomy, resection of a subvalvular ring, myotomy and supravalvular patch plasty. Fifty-seven patients were treated by AVP, in only 11 patients was AVP the first procedure, 46 had had one or more previous operations. Total hospital mortality was 12.2%; in the last 37 cases there was only one death. Two patients suffered permanent AV block. The mean left ventricular-aorta gradient was reduced from 94 +/- 24 mmHg to 14 +/- 15 mmHg after AVP. In our clinical material the indications for AVP (n = 57) have been the following: valvular aortic stenosis with narrow annulus (8 patients), diffuse subaortic stenosis (20) (from collar-like to tunnel-like, out of these patients 6 with Shone-complex), multi-level stenosis (20), outgrown prosthesis (4), hypertrophic obstructive cardiomyopathy (5). In comparison to the apico-aortic conduit procedure and total replacement of the aortic root by homograft, the clinical results indicate AVP to be a simple and easy-to-apply operative technique.

Clinical manifestations of dynamic left ventricular outflow tract stenosis in infants with d-transposition of the great arteries with intact ventricular septum

Four infants with d-transposition of the great arteries and intact ventricular septum who manifested early clinical symptoms and deterioration due to dynamic left ventricular outflow stenosis are presented. All four had an anatomically adequate atrial septal defect, made at the initial balloon atrial septostomy, that was later confirmed intraoperatively. Two infants continued to have a low arterial oxygen saturation level because of inadequate interatrial mixing, and one of these had severe persistent cyanosis and was treated with the Mustard operation at age 4 days. The other two infants subsequently presented with hypercyanotic spells at age 3 months. All four infants had features of dynamic left ventricular outflow stenosis on hemodynamic, angiocardiographic and echocardlographic studies. The left ventricular outflow pressure gradient was shown to increase after administration of isoproterenol in one infant, and relief of a cyanotic spell with reduction of left ventricular systolic pressure was achieved in another after intravenous administration of propranolol. The Mustard operation relieved symptoms in all infants. The effect of left ventricular outflow tract stenosis on the mechanisms responsible for interatrial mixing in d-transposition of the great arteries with intact ventricular septum is discussed.

Bronchopulmonary circulation in d-transposition of the great arteries: Possible role in genesis of accelerated pulmonary vascular disease

Hemodynamic and angiograhic data from 209 patients with d-transposition of the great arteries were reviewed to estimate the incidence of prominent bronchopulmonary circulation and to explore its role in the genesis of accelerated pulmonary vascular disease in these patients. The degree of bronchopulmonary circulation was assessed visually by considering the extent of the pulmonary arterial opacification and the circulation to the left atrium. An initial survey study revealed a marked degree of collateral circulation in 20 of 138 patients with d-transposition having cardiac catheterization before age 2 years at the Hospital for Sick Children, Toronto, between 1967 and 1972. Detailed analysis of 71 additional patients with d-transposition aged 1 week to 72 months (mean 17 months) studied at Children's Memorial Hospital, Chicago, between 1967 and 1974 showed collateral circulation of marked degree in 23 and of mild degree in 14. The bronchopulmonary collateral vessels were more freqently demonstrated in the patients with intact ventricular septum than in those with ventricular septal defect or left ventricular outflow tract stenosis. In a prospective study in 12 of 15 patients during cardiac catheterization the functional patency of the bronchopulmonary collateral circulation was demonstrated by obstructing pulmonary blood flow in the right or left pulmonary artery, or both, with an inflated balloon and obtaining from the pulmonary arterial segment distal to the occlusion blood with an oxygen saturation similar to that of the aorta. A hypothesis is presented concerning the role of systemic hypoxemia and local pulmonary hypoxemia induced by way of the bronchopulmonary collateral vessels and the bronchial arterial vasovasorum in promoting pulmonary vasoconstriction. It is suggested that increased pulmonary blood flow and pressure due to the physiologic features of ventricular septal defect, patent ductus arteriosus or transposition of the great vessels, in the face of this regionally increased hypoxemia results in accelerated pulmonary vascular disease.