Asian Cardiovasc Thorac Ann 1999;7:282-286
© 1999 Asia Publishing EXchange Pte Ltd
Enlargement of Small Aortic Annulus by Modified Manouguian's Technique
Nainar Madhu Sankar, PhD,
Sethurathinam Rajan, MS, MCh,
Rajarathinam Karnan Kalyan Singh, MD,
Kotturathu Mammen Cherian, FRACS
Madras Medical Mission
Institute of Cardiovascular Diseases
Chennai, India
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For reprint information contact: Kotturathu Mammen Cherian, FRACS Tel: 91 44 625 9801 Fax: 91 44 625 9920 Madras Medical Mission, Institute of Cardiovascular Diseases, 4A, Dr. Jayalalitha Nagar, Mogappair East, Chennai 600050, Tamil Nadu, India.
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Abstract
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From January 1981 to June 1994, 17 patients underwent aortic annulus enlargement by a modified Manouguian's technique. A small aortic root associated with stenotic lesions was the main indication. The ages of the patients ranged from 5 to 55 years (mean, 21 ± 14 years). There were 10 males and 7 females. Four had concomitant mitral valve replacement, 2 had open mitral valvotomy, 1 underwent ventricular septal defect closure, excision of a subaortic membrane, and ascending aortic replacement. The aortic roots were enlarged to between 20 to 30 mm. A Dacron patch was used in 16 patients and glutaraldehyde-treated autologous pericardium was used in 1. Two patients (12%) died in the postoperative period, 1 due to hemorrhage and the other due to septicemia. Mitral regurgitation (grade 1) was seen in 1 patient postoperatively but there was no further deterioration on serial evaluation. Four patients were lost to follow-up. Of the 11 followed up over a period of 10 years, 7 were in New York Heart Association functional class I and 4 were in class II.
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Introduction
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Aortic valve replacement in patients with a small hypoplastic annulus is a technically challenging problem. Replacement with a small prosthesis may result in prosthesis-patient mismatch with consequent left ventricular dysfunction. Moreover, a small prosthesis in a narrow aortic annulus may not provide clinical or hemodynamic benefits to a large or physically active individual. Thus, an annulus-enlarging procedure such as that described by Manouguian and colleagues,1 Nicks and colleagues,2 or Konno and colleagues3 is needed. We describe our experience of 17 patients in whom the Manouguian technique was used with modifications.
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Patients and Methods
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From January 1981 to June 1994, 597 patients underwent aortic valve replacement in our institution. Among these were 17 patients (3%) who had patch enlargement of the aortic annulus during isolated aortic valve replacement or of both aortic and mitral annuli during double valve replacement. Ages ranged from 5 to 55 years (mean, 21 ± 14). There were 10 males and 7 females and the body surface areas for the whole group ranged from 0.64 to 1.69 m2 (mean, 1.33 ± 0.3 m2). There were 4 children, 1 male and 3 females, one of whom had active bacterial endocarditis with an aortic root abscess; exteriorization of the abscess cavity with aortic root widening and valve replacement were performed. The adult patients comprised 6 males and 7 females, 4 had concomitant mitral valve replacement, 2 had open mitral valvotomy, 1 underwent ventricular septal defect closure, excision of a subaortic membrane, and replacement of the ascending aorta with a Dacron graft. The primary valvular pathology was rheumatic in 13 patients. Two patients had congenital bicuspid valves. Another patient who had previous surgery consisting of patent ductus arteriosus ligation, aortic valvotomy, and excision of a fibromatous left ventricular outflow tract obstruction, underwent ventricular septal defect closure, excision of the left ventricular outflow tract obstruction, patch repair of a saccular aneurysm of the ascending aorta, aortic annulus enlargement, and aortic valve replacement. The mean preoperative New York Heart Association functional class was 3.2 ± 0.7.
Adult patients were operated under standard cardio-pulmonary bypass with moderate hypothermia. Profound hypothermia and low flow rates were used in the pediatric patients. Myocardial protection was carried out with cold blood cardioplegia injected every 30 minutes and topical cooling. Through an oblique aortotomy, the diseased valve was excised and the annulus was sized. If the annulus did not accept a 19-mm obturator, root widening was undertaken. The aortotomy incision was extended along the commissure between the left coronary and the noncoronary sinuses, across the center of the fibrous origin of the anterior mitral leaflet 1.5 to 2 cm short of its free margin (Figures 1A and 1B
). The attachment at the base of the aorta was divided and the left atrium was incised 1.5 cm posteriorly. A triangular Dacron patch (Gore-Tex; WL Gore, Flagstaff, AZ, USA) with the apex pointing towards the free margin was sutured to the defect in the anterior mitral leaflet (AML) up to the level of the aortic root with two continuous 4/0 or 5/0 Proline sutures (Ethicon Ltd, Edinburgh, Scotland, UK) with pledgets (Figures 2A and 2B). Use of a pericardial patch is associated with the risk of kinking of the root, aneurysmal dilatation, and rupture, hence a Dacron patch was preferred.
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Figure 1. (A) The aortotomy incision extending into the anterior mitral leaflet. (B) The incision in the commissure between the left and noncoronary cusps. L = left sinus, LA = left atrium, P = posterior, R = right sinus, RA = right atrium.
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Figure 2. (A) The defect in anterior mitral leaflet and the opened left atrium. (B) Closure of the defect in the anterior mitral leaflet with a Gore-Tex patch. AML = anterior mitral leaflet, LA = left atrium.
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The aortic valve prosthesis was inserted with a continuous suture. In the left and right coronary sinuses and at the noncoronary-right coronary commissure, interrupted sutures of either 3/0 Prolene or 3/0 Ti-Cron (Davis & Geck, Danbury, CT, USA) were passed through the valve annulus, the Dacron patch, and a triangular piece of pericardium; the last two sutures being left uncut. The defect in the roof of left atrium was closed with the pericardiac patch. This prevents tension on the suture line and reinforces the neo-annulus, thus reducing the risk of hemorrhage (Figures 3A and 3B). A separate 3/0 or 4/0 Prolene suture was used to reinforce the Gore-Tex patch, aortic valve, and pericardium. The defect in the aorta was closed, taking the shape of a tongue (Figures 4A and 4B). Care was taken to center the incision in the AML so that its symmetry was maintained to prevent iatrogenic mitral regurgitation. In patients requiring concomitant mitral valve replacement after enlargement of the aortic annulus, this was performed before aortic valve replacement (Figures 5A and 5B).
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Figure 3. (A) The prosthetic valve in position after widening the root. (B) Closure of the roof of the left atrium with a pericardial patch. LA = left atrium.
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Figure 4. (A) The remaining part of the Gore-Tex patch to be incorporated in the closure of the aortotomy. (B) The widened aortic root with the prosthesis at the end of the procedure.
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Figure 5. (A) Placement of the patch in relation to the mitral valve. (B) Position of the patch after combined aortic and mitral valve replacement. AV = aortic valve, MV = mitral valve.
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A Gore-Tex patch was used in 16 patients. Glutaraldehyde-treated pericardium was used in 1 patient for aortic root widening. A Lillehei-Kaster valve (Medical Inc., Inver Grove Heights, MN, USA) was used for valve replacement in 2 patients early in our experience, 7 had Bjork-Shiley prostheses (Shiley, Inc., Irvine, CA, USA), 4 had Starr-Edwards (Baxter Healthcare, Irvine, CA, USA), 2 each had Medtronic-Hall (Medtronic, Inc., Minneapolis, MN, USA) and St. Jude Medical valves (St. Jude Medical, Inc., St. Paul, MN, USA) in the aortic position. Among those who had mitral valve replacement, 2 received Starr-Edwards valves and the other 2 received St. Jude Medical valves. In the 5-year-old child with an aortic root abscess and type I aortic dissection, after debridement of the abscess cavity, the homograft was stitched so that it was exteriorized from the aortic annulus where the valve was to be seated; a pericardial patch was used for aortic root widening. All cases of suspected or confirmed infective endocarditis were treated with appropriate antibiotics for 4 to 6 weeks before surgery, followed by 4 to 6 weeks of parenteral antibiotics during the postoperative period. The patient who had previous surgery developed a bleeding diathesis during surgery and had extensive adhesions and poor anatomic delineation of the intrathoracic structures. All patients routinely underwent echocardiography before discharge to evaluate valve function. Postoperative follow-up was carried out at 3 and 6 months and yearly thereafter. Patient follow-up was achieved by direct contact with the patients and their family physician.
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Results
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The aortic roots were enlarged by 4 to 6 mm to between 20 to 30 mm. The mean cardiopulmonary bypass time was 129 ± 34 minutes. Aortic crossclamp times ranged from 43 to 128 minutes (mean, 77 ± 24 minutes). All 17 patients required inotropic support for 24 to 48 hours. Mitral regurgitation (grade 1) was seen in 1 patient postoperatively (6%). However, this did not progress on serial evaluation. Depending upon hemodynamic status, all patients were electively ventilated for 24 to 48 hours. Two patients (12%) died in the postoperative period, one due to septicaemia and the other due to hemorrhage. Four of the surviving 15 patients were lost to follow-up. Of the 11 patients followed up over a period of 10 years, 7 are in New York Heart Association functional class I and 4 are in class II.
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Discussion
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Manouguian and colleagues1 reported their surgical experience of patch enlargement of a narrow aortic valve annulus by posterior incision. In the techniques described by Nicks and colleagues2 and Blank and colleagues,4 the incision is continued downwards into the noncoronary sinus, dividing the aortic annulus and extending only as far as the origin of the AML. This enlarges mainly the supravalvular area and the aortic valve is usually widened by only a few millimeters. The indications for root enlargement and the advantages of this procedure are listed in Tables 1 and 2. In our series, the indication was a narrow aortic root in all cases. Narrowing of the aortic and mitral annuli was present in 6 patients and one child had bacterial endocarditis. If the aortic mitral septum is enlarged by more than 30 mm, the ring of the mitral prothesis protrudes into the left ventricular outflow tract. Precise surgical incision is necessary when the aortic incision is extended through the intervalvular trigone. It is important that the incision is directed precisely towards the center of the fibrous origin of the AML to avoid distortion due to patch enlargement.
Ranganathan and colleagues5 reported that the degree of enlargement of the aortic annulus is determined by extension of the aortic incision into the AML maximally to its appositional portion. The AML is the ideal site for extension of the aortic root incision because there is continuity between the posterolateral part of the aortic root and the anterior leaflet of the mitral valve. The portion of the aortic annulus to which the AML is attached exhibits no change during the cardiac cycle, as shown by cineradiographic studies.6 The AML is functionally passive and no impairment of mitral valve function results from the patch enlargement technique. Moreover, the AML consists of collagenous fibers and is quite strong and resistant. Patch repair of the anterior leaflet of the mitral valve is thus possible without much technical difficulty.
There is no permanent impairment of mitral function when the extension of the aortic incision into the AML is limited to approximately 1 cm because the initial portion of the AML is not actively involved in the valve action. However, when the incision extends into the appositional portion of the AML, the possibility of subsequent functional impairment of the mitral valve due to patch shrinking, stiffening, or distortion of the AML cannot be excluded.6 In 4 cases where fresh autologous pericardium was used by Kawachi and colleagues,7 no complications related to the pericardial patch occurred during the 5-year follow-up. Other studies with long-term follow-up have noted the durability of autologous pericardium in adults, which did not become aneurysmal in the aortic root or the left ventricle.8
The reasons for the absence of mitral regurgitation after extension of the aortic root incision into the AML are: the origin of the AML from the left fibrous annulus between the left and right trigone is not folded or stretched during the cardiac cycle; unlike the posterior mitral leaflet during systole and diastole, the AML is pressed against the posterior leaflet and is opened only mechanically by external function; and during systole, the non-appositional portion of the AML meets the appositional portion at a right angle and a greater portion of the posterior leaflet is in apposition to the anterior leaflet.5
In patients with a small aortic annulus, the decision to insert a small prosthesis (diameter of 21 mm or less) or to enlarge the annulus is controversial.9 The contrain-dications for aortic root enlargement include relative mitral incompetence that does not require immediate valve replacement and calcified aortic-mitral septum and AML. A small prosthesis in a normal aortic annulus may not provide clinical or hemodynamic benefits to a large or physically active individual. Foster and colleagues10 found no correlation between aortic transvalvular gradients and clinical status during long-term follow-up of patients with a body surface area of 1.6 m2 who had received 17-mm or 19-mm Bjork-Shiley valves. In our patients whose mean body surface area was 1.33 m2, aortic valve replacement with a 19-mm valve (Medtronic-Hall or St. Jude Medical) was found to be adequate with acceptable gradients and good functional benefits.
In patients undergoing double valve replacement, the sizes of the prosthetic valves are crucial. If the aortic-mitral septum is enlarged by more than 30 mm, the ring of the mitral prosthesis protrudes under the aortic prosthesis and causes obstruction of the left ventricular outflow tract. Kawachi and colleagues7 reported exchanging 33-mm Hancock valves for 29-mm Hancock valves in 2 patients because of left ventricular outflow tract obstruction. When the left ventricular outflow tract is narrowed along with aortic valve stenosis or incompetence, aortoventriculoplasty as described by Konno and colleagues3 and Rastan and colleagues11 can be performed.
In this study, the aortic roots could be enlarged by 4 to 6 mm, allowing placement of a larger prosthetic valve. We recommend aortic root widening prior to valve replacement in patients with a small aortic root to avoid prosthesis-patient mismatch in adults and to preclude redo valve replacement surgery at a later date in children.
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References
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Manouguian S, Abu-Aishah N, Neitzel J. Patch enlargement of the aortic and mitral valve rings with aortic and mitral valve replacement. Experimental study. J Thorac Cardiovasc Surg 1979;78:394–401.[Abstract]
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Nicks R, Cartmill T, Bernstein L. Hypoplasia of the aortic root. Thorax 1970;25:339–49.[Abstract/Free Full Text]
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Konno S, Imai Y, Iida Y, Nakagima M, Tatasuno K. New method for prosthetic valve replacement in congenital aortic stenosis associated with hypoplasia of the aortic valve ring. J Thorac Cardiovasc Surg 1975;70:909–17.[Abstract]
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Blank RH, Pupello DF, Bessone LN, Harrison EL, Sbar S. Method of managing the small aortic annulus during valve replacement. Ann Thorac Surg 1976;22:356–61.[Abstract]
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Ranganathan N, Lam JHE, Wigle ED, Silver MD. Morphology of human mitral valve. II. The valve leaflets. Circulation 1970;41:459–67.[Abstract/Free Full Text]
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Manouguian S, Seybold-Epting W. Patch enlargement of the aortic valve ring by extending the aortic incision into the anterior mitral leaflet. New operative technique. J Thorac Cardiovasc Surg 1979;78:402–12.[Abstract]
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Kawachi Y, Tohinage R, Tokunaja K. Eleven-year follow-up study of aortic or aortic mitral annulus enlargement procedure by Manouguian's technique. J Thorac Cardiovasc Surg 1992;104:1259–63.[Abstract]
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David TE, Feindel CM, Ropchan GV. Reconstruction of the left ventricle with autologous pericardium. J Thorac Cardiovasc Surg 1987;94:710–4.[Abstract]
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Jaffe WM, Corerdale HA, Roche AHG, Whitelock RML, Neutz JM, Barratt-Boyes BG. Rest and exercise hemodynamics of 20 to 23 mm allograft, Medtronic Intact (porcine) and St. Jude Medical valves in the aortic position. J Thorac Cardiovasc Surg 1990;100:167–74.[Abstract]
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Foster AH, Tracy CM, Greenberg GJ, McIntosh CL, Clark RE. Valve replacement in narrow aortic roots serial hemodynamics and long-term clinical outcome. Ann Thorac Surg 1986;42:506–16.[Abstract]
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Rastan H, Abu-Aishah N, Rastan D, Heisig B, Konez J, Bojornstad PG, et al. Results of aortoventriculoplasty in 21 consecutive patients with left ventricular outflow tract obstruction. J Thorac Cardiovasc Surg 1978;75:659–69.[Abstract]
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Abstract
Introduction
