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Mitral valve replacement through the aortic root
Mitral valve replacement through the aortic root This report discusses the case histories of two patients who had had previous cardiac operations and required extensive reoperations including mitral valve replacement. In both patients the replacement of the mitral valve was performed through the aortic root. This rare approach to the mitral valve, conducted with remarkable facility in these patients, encourages more liberal use of transaortic mitral valve operations in selected patients. (J 'fHORAC CARDIOVASC SURG 1994;107:1334-6)
Hassan Najafi, MD, and James R. Hemp, MD, Chicago, Ill.
In considering mitral valve replacement (MVR), the surgeon has several alternative approaches for exposure and execution of the procedure. The conventional incisions include a vertical left atriotomy, right atriotomy with atrial septotomy, and a cardiotomy through the roof of the left atrium. 1 Unconventional or rare approaches include (I) left ventriculotomy, (2) combined incision, cutting across the base of the right atrial appendage, the septum, and the superior aspect of the left atrium.? and (3) aortotomy.v" Replacement of the mitral valve through the aortic root was first demonstrated by Helseth and associates' in an operative movie shown at the meeting of the Society of Thoracic Surgeons in January 1983. Since then, to our knowledge only two reports have appeared in the literature (a total of eight patients in the series), indicating the rare use of this route for MVR.3, 4 Our experience with two instances of remarkably easy MVR through the aortic root under anatomic conditions initially considered unfavorable encouraged the submission of this report. Case reports CASE I. A 53-year-old man had undergone aortic valve replacement with a Bjork-Shiley prosthesis (Shiley, Inc., Irvine, Calif.) II years earlier. He had done well for the ensuing years but was recently admitted in congestive heart failure. Cardiac studies revealed a well functioning aortic valve prosthesis, severe
From the Department of Cardiovascular-Thoracic Surgery, Rush Medical College, Rush-Presbyterian-St. Luke's Medical Center, Rush Heart Institute, Chicago, Ill. Received for publication Aug. 17, 1993. Accepted for publication Oct. 17, 1993. Address forreprints: Hassan Najafi,MD, DepartmentofCardiovascular-Thoracic Surgery,Rush-Presbyterian-St. Luke'sMedical Center, 1653 W. Congress Parkway, 714 Jelke, Chicago, IL 60612. Copyright © 1994 by Mosby-Year Book, Inc. 0022-5223/94 $3.00 + 0
1334
12/1/52314
mitral regurgitation, aortic root aneurysm, a dilated, but vigorous left ventricle, and normal coronary arteries. The operation was performed on June 23,1992. Cardiopulmonary bypass was begun and, while the patient was being cooled, the exceedingly large heart and the aneurysmal ascending aorta were dissected free. A generous transverse aortotomy was made. Myocardial preservation was achieved by antegrade perfusion of cold blood cardioplegic solution. The markedly dilated sinuses of Valsalva indicated the need for insertion of a conduit. The Bjork-Shiley aortic valve was excised, with a relatively large but somewhat rigid anulus left behind. At this time the fibrotic septal leaflet of the mitral valve with its shortened chordae tendineae came into perfect view of the surgeon. Temptation led to excision of the mitral valve through the aortic root, and ample exposure permitted expeditious placement of a 33 mm St. Jude Medical mechanical prosthesis (St. Jude Medical, Inc., St. Paul, Minn.). This was followed by insertion of a 31 mm St. Jude Medical conduit to which the coronary orifices were implanted. It was pleasantly surprising to be able to pass with ease the 33 mm St. Jude Medical mitral prosthesis through a smaller and somewhat rigid aortic valve anulus. The patient was discharged after an uneventful postoperative course. He remains in New York Heart Association functional class I, working full-time and leading a normal lifestyle. CASE 2. A 57-year-old man with Marfan's syndrome underwent emergency replacement of a segment of the ascending aorta for acute aortic dissection at the age of 47 years. He had done well until a few weeks earlier when he was admitted to another institution in severe congestive heart failure. Angiography revealed severe aortic and mitral regurgitation and an aneurysmal process involving the sinuses of Valsalva, distal ascending aorta, and most of the transverse segment of the aortic arch. The short Dacron tube graft was noted. The coronary arteries and left ventricle were normal. The dissecting aortic aneurysm tapered as it reached the end of the transverse aorta with aneurysmal dilatation reappearing at the initial portion of the descending aorta. This anatomic observation encouraged the idea of staging the operation into all that could safely be accomplished through a repeat sternotomy and then consider operating on the descending aorta later through a left thoracotomy. The operation was performed on June I, 1993. After adequate dissection, arch reconstruction was found to be mandatory. Accordingly, the brachiocephalic arteries were encircled
The Journal of Thoracic and Cardiovascular Surgery Volume 107, Number 5
withtourniquets. With the aid of total cardiopulmonarybypass, the aneurysmal ascendingaorta was clamped proximal to the innominateartery. The aortic root was entered through a transverseincision and the coronaryorifices were perfusedwith cold blood cardioplegic solution. The frayed aortic leaflets were excised. The aortic anulus readily permitted excision of the mitral valveand insertion of a 33 mm St. Jude Medical mitral prosthesis. While MVR was beingdone, the patient was cooled to 24° C in anticipation of arch reconstruction. The oldgraft and aneurysmalascendingaorta and mostof the transverse segmentwere excised. The innominateand left commoncarotid arteries wereperfusedthrough an independentline from the oxygenator. A 30 mm Dacron graft was sutured directlyto the aorta at the originof the leftsubclavianartery and a narrow aortic segment containing the orifices of the innominate and left common carotid arteries. On completion of arch reconstruction, the clamp on the descending aorta was transferred to the Dacron graft proximal to the innominate artery. Thedurationofselective extracorporealcerebralcirculationwas 40 minutes. Insertionof a 31 mm St. Jude Medical conduit to which the coronary orifices were implanted and a final anastomosis betweenthe conduit and the arch Dacron graft completed the operation. The heart maintained satisfactory systemic circulation with a cardiac index of 2.8 Lzmin. The patient's coursewas complicated only by the need for prolonged intubation. He was dischargedon the eleventhpostoperative day and remains free of symptoms.
Discussion These two instances of MVR through the aortic root under conditions not ideal for this approach have convinced us that this approach could have been used more frequently in the past and therefore should be more liberally applied in the future. The advantages are obvious, particularly in reoperation on the heart. The procedure does not necessitate extensive release of adhesions surrounding the heart and, by obviating another cardiotomy, it minimizes mechanical trauma to the heart and shortens the duration of myocardial ischemia. The possible disadvantages include injury to the aortic root and improper coaption of the valve leading to paravalvular regurgitation. The facility with which the larger mitral prosthesis could be passed through the aortic anulus was surprising, and the exposure was excellent for the entire circumference of the mitral ring in both patients. Of course, this approach is feasible only if the aortic anulus is large enough to accommodate safe passage of the mitral valve prosthesis. In the two cases described here the aortic anulus permitted the passage of a 33 mm St. Jude Medical mitral valve while accommodating a 31 mm aortic conduit. An important anatomic consideration is the degree of elasticity of the aortic anulus. Obviously, a small and inelastic aortic valve ring obviates the use of this approach. Initially, this technique should be reserved for a select group of patients satisfying certain anatomic and patho-
Najafi and Hemp
1 33 5
physiologic requirements. Ideal indications consist of combined mitral and aortic regurgitation and aortic root aneurysm such as seen in Marfan's anomaly. Indeed, one of the first two patients described by Carmichael, Cooley, and Favor" in December 1983 and all six patients described by Crawford and Coselli 4 in March 1988 had a combination of aortic root aneurysm and bivalvular regurgitation. After the aortic leaflets are excised, the septal leaflet of the mitral valve with its chordae tendineae will be clearly in the view of the surgeon. The mural leaflet cannot be seen until the septal leaflet is removed. Care should be taken to leave a sufficient rim of tissues when the leaflets are excised. The surgeon begins the mitral excision by making an incision (with a No. 11 blade) in the septal leaflet beneath the left coronary sinus of Val salva, leaving behind approximately a 5 mm rim of mitral anulus. This incision is extended in both directions with scissors until the entire septal leaflet is detached. At this time the chordae are transected at their point of insertion on the papillary muscle. Partial resection of the mural leaflet is begun by dividing its chordae tendineae first. After the safety and feasibility of this approach has been established, 2-0 nonabsorbable, multistrand sutures with swedged-on large Teflon pledgets and two needles are used to insert the valve. We prefer, if possible, to place each suture through the native tissue and the sewing ring, rather than placing all sutures through the anulus first and then passing them successively through the prosthesis. The suturing is begun in the anulus posteriorly at a point corresponding to the middle of the mural leaflet. The surgeon has the choice of inverting or everting the anulus by placing the Teflon pledgets in horizontal orientation on the atrial or ventricular side of the anulus. After all the sutures are placed, the valve is lowered in place initially with traction on the sutures until the valve is at the level of the aortic anulus. Then tension on the sutures is released while the valve is passed through the outflow tract of the left ventricle into position. It is imperative to account for the proper course of every suture and satisfactory apposition of the sewing ring against the anulus before the sutures are tied. Ligation is begun in the middle of the anulus posteriorly (the farthest point), advancing from there in both directions successively until the top of the anulus has been reached, beneath the aortic valve. As experience is gained, replacing the mitral valve without totally excising the native tissues should be practical. The aorta need not be aneurysmal for this approach to be considered. The feasibility of transaortic MVR should be explored in patients with bivalvular regurgitation resulting from other etiologic mechanisms such as rheumatic fever and endocarditis.
I 336
The Journal of Thoracic and Cardiovascular Surgery May 1994
Najafi and Hemp
It is safe to suggest that this approach, when feasible, may be desirable even in patients in whom the mitral valve can readily be excised and replaced through a conventional incision. To state this differently, in a patient with bivalvular disease the practicality of MVR through the aortic root (after excision of aortic leaflets) should be thoroughly examined before the surgeon commits to an atriotomy. This approach is particularly useful in patients who have previously undergone cardiac surgery. The transaortic approach obviates the need for release of adhesions surrounding the left ventricle. We acknowledge with great admiration the contributions of two previous reports on this subject.v" We also wish to increase the awareness of our colleagues and cautiously encourage the application of this undoubtedly underused approach to MVR in carefully selected patients. Ms. Elizabeth Wolff's efforts in preparing this report are greatly appreciated.
I.
2.
3.
4.
5.
REFERENCES Meyer BW, Verska JJ, Lindesmith GG, Jones Jc. Open repair of mitral valve lesions: the superior approach. Ann Thorac Surg 1965;1:453-7. Berrkklouw E, Hiisamettin E, Schoenberger JP. Combined superior-transseptal approach to the left atrium. Ann Thorae Surg 1991;51:293-5. Carmichael MJ, Cooley DA, Favor AS. Aortic and mitral valve replacement through a single transverse aortotomy: a useful approach in difficult mitral valveexposure. Tex Heart Inst J 1983;10:415-9. Crawford ES, Coselli JS. Marfan's syndrome: combined composite valve graft replacement of the aortic root and transaortic mitral valve replacement. Ann Thorac Surg 1988;45:296-302. Helseth HK, Haglin JJ, Stenlund RR, Peterson CR. Composite graft replacement of the aortic root and ascending aorta. Movie presented at the meeting of the Society of Thoracic Surgeons, January 17-19, 1983, San Francisco, California.
Hassan Najafi, MD, and James R. Hemp, MD, Chicago, Ill.
In considering mitral valve replacement (MVR), the surgeon has several alternative approaches for exposure and execution of the procedure. The conventional incisions include a vertical left atriotomy, right atriotomy with atrial septotomy, and a cardiotomy through the roof of the left atrium. 1 Unconventional or rare approaches include (I) left ventriculotomy, (2) combined incision, cutting across the base of the right atrial appendage, the septum, and the superior aspect of the left atrium.? and (3) aortotomy.v" Replacement of the mitral valve through the aortic root was first demonstrated by Helseth and associates' in an operative movie shown at the meeting of the Society of Thoracic Surgeons in January 1983. Since then, to our knowledge only two reports have appeared in the literature (a total of eight patients in the series), indicating the rare use of this route for MVR.3, 4 Our experience with two instances of remarkably easy MVR through the aortic root under anatomic conditions initially considered unfavorable encouraged the submission of this report. Case reports CASE I. A 53-year-old man had undergone aortic valve replacement with a Bjork-Shiley prosthesis (Shiley, Inc., Irvine, Calif.) II years earlier. He had done well for the ensuing years but was recently admitted in congestive heart failure. Cardiac studies revealed a well functioning aortic valve prosthesis, severe
From the Department of Cardiovascular-Thoracic Surgery, Rush Medical College, Rush-Presbyterian-St. Luke's Medical Center, Rush Heart Institute, Chicago, Ill. Received for publication Aug. 17, 1993. Accepted for publication Oct. 17, 1993. Address forreprints: Hassan Najafi,MD, DepartmentofCardiovascular-Thoracic Surgery,Rush-Presbyterian-St. Luke'sMedical Center, 1653 W. Congress Parkway, 714 Jelke, Chicago, IL 60612. Copyright © 1994 by Mosby-Year Book, Inc. 0022-5223/94 $3.00 + 0
1334
12/1/52314
mitral regurgitation, aortic root aneurysm, a dilated, but vigorous left ventricle, and normal coronary arteries. The operation was performed on June 23,1992. Cardiopulmonary bypass was begun and, while the patient was being cooled, the exceedingly large heart and the aneurysmal ascending aorta were dissected free. A generous transverse aortotomy was made. Myocardial preservation was achieved by antegrade perfusion of cold blood cardioplegic solution. The markedly dilated sinuses of Valsalva indicated the need for insertion of a conduit. The Bjork-Shiley aortic valve was excised, with a relatively large but somewhat rigid anulus left behind. At this time the fibrotic septal leaflet of the mitral valve with its shortened chordae tendineae came into perfect view of the surgeon. Temptation led to excision of the mitral valve through the aortic root, and ample exposure permitted expeditious placement of a 33 mm St. Jude Medical mechanical prosthesis (St. Jude Medical, Inc., St. Paul, Minn.). This was followed by insertion of a 31 mm St. Jude Medical conduit to which the coronary orifices were implanted. It was pleasantly surprising to be able to pass with ease the 33 mm St. Jude Medical mitral prosthesis through a smaller and somewhat rigid aortic valve anulus. The patient was discharged after an uneventful postoperative course. He remains in New York Heart Association functional class I, working full-time and leading a normal lifestyle. CASE 2. A 57-year-old man with Marfan's syndrome underwent emergency replacement of a segment of the ascending aorta for acute aortic dissection at the age of 47 years. He had done well until a few weeks earlier when he was admitted to another institution in severe congestive heart failure. Angiography revealed severe aortic and mitral regurgitation and an aneurysmal process involving the sinuses of Valsalva, distal ascending aorta, and most of the transverse segment of the aortic arch. The short Dacron tube graft was noted. The coronary arteries and left ventricle were normal. The dissecting aortic aneurysm tapered as it reached the end of the transverse aorta with aneurysmal dilatation reappearing at the initial portion of the descending aorta. This anatomic observation encouraged the idea of staging the operation into all that could safely be accomplished through a repeat sternotomy and then consider operating on the descending aorta later through a left thoracotomy. The operation was performed on June I, 1993. After adequate dissection, arch reconstruction was found to be mandatory. Accordingly, the brachiocephalic arteries were encircled
The Journal of Thoracic and Cardiovascular Surgery Volume 107, Number 5
withtourniquets. With the aid of total cardiopulmonarybypass, the aneurysmal ascendingaorta was clamped proximal to the innominateartery. The aortic root was entered through a transverseincision and the coronaryorifices were perfusedwith cold blood cardioplegic solution. The frayed aortic leaflets were excised. The aortic anulus readily permitted excision of the mitral valveand insertion of a 33 mm St. Jude Medical mitral prosthesis. While MVR was beingdone, the patient was cooled to 24° C in anticipation of arch reconstruction. The oldgraft and aneurysmalascendingaorta and mostof the transverse segmentwere excised. The innominateand left commoncarotid arteries wereperfusedthrough an independentline from the oxygenator. A 30 mm Dacron graft was sutured directlyto the aorta at the originof the leftsubclavianartery and a narrow aortic segment containing the orifices of the innominate and left common carotid arteries. On completion of arch reconstruction, the clamp on the descending aorta was transferred to the Dacron graft proximal to the innominate artery. Thedurationofselective extracorporealcerebralcirculationwas 40 minutes. Insertionof a 31 mm St. Jude Medical conduit to which the coronary orifices were implanted and a final anastomosis betweenthe conduit and the arch Dacron graft completed the operation. The heart maintained satisfactory systemic circulation with a cardiac index of 2.8 Lzmin. The patient's coursewas complicated only by the need for prolonged intubation. He was dischargedon the eleventhpostoperative day and remains free of symptoms.
Discussion These two instances of MVR through the aortic root under conditions not ideal for this approach have convinced us that this approach could have been used more frequently in the past and therefore should be more liberally applied in the future. The advantages are obvious, particularly in reoperation on the heart. The procedure does not necessitate extensive release of adhesions surrounding the heart and, by obviating another cardiotomy, it minimizes mechanical trauma to the heart and shortens the duration of myocardial ischemia. The possible disadvantages include injury to the aortic root and improper coaption of the valve leading to paravalvular regurgitation. The facility with which the larger mitral prosthesis could be passed through the aortic anulus was surprising, and the exposure was excellent for the entire circumference of the mitral ring in both patients. Of course, this approach is feasible only if the aortic anulus is large enough to accommodate safe passage of the mitral valve prosthesis. In the two cases described here the aortic anulus permitted the passage of a 33 mm St. Jude Medical mitral valve while accommodating a 31 mm aortic conduit. An important anatomic consideration is the degree of elasticity of the aortic anulus. Obviously, a small and inelastic aortic valve ring obviates the use of this approach. Initially, this technique should be reserved for a select group of patients satisfying certain anatomic and patho-
Najafi and Hemp
1 33 5
physiologic requirements. Ideal indications consist of combined mitral and aortic regurgitation and aortic root aneurysm such as seen in Marfan's anomaly. Indeed, one of the first two patients described by Carmichael, Cooley, and Favor" in December 1983 and all six patients described by Crawford and Coselli 4 in March 1988 had a combination of aortic root aneurysm and bivalvular regurgitation. After the aortic leaflets are excised, the septal leaflet of the mitral valve with its chordae tendineae will be clearly in the view of the surgeon. The mural leaflet cannot be seen until the septal leaflet is removed. Care should be taken to leave a sufficient rim of tissues when the leaflets are excised. The surgeon begins the mitral excision by making an incision (with a No. 11 blade) in the septal leaflet beneath the left coronary sinus of Val salva, leaving behind approximately a 5 mm rim of mitral anulus. This incision is extended in both directions with scissors until the entire septal leaflet is detached. At this time the chordae are transected at their point of insertion on the papillary muscle. Partial resection of the mural leaflet is begun by dividing its chordae tendineae first. After the safety and feasibility of this approach has been established, 2-0 nonabsorbable, multistrand sutures with swedged-on large Teflon pledgets and two needles are used to insert the valve. We prefer, if possible, to place each suture through the native tissue and the sewing ring, rather than placing all sutures through the anulus first and then passing them successively through the prosthesis. The suturing is begun in the anulus posteriorly at a point corresponding to the middle of the mural leaflet. The surgeon has the choice of inverting or everting the anulus by placing the Teflon pledgets in horizontal orientation on the atrial or ventricular side of the anulus. After all the sutures are placed, the valve is lowered in place initially with traction on the sutures until the valve is at the level of the aortic anulus. Then tension on the sutures is released while the valve is passed through the outflow tract of the left ventricle into position. It is imperative to account for the proper course of every suture and satisfactory apposition of the sewing ring against the anulus before the sutures are tied. Ligation is begun in the middle of the anulus posteriorly (the farthest point), advancing from there in both directions successively until the top of the anulus has been reached, beneath the aortic valve. As experience is gained, replacing the mitral valve without totally excising the native tissues should be practical. The aorta need not be aneurysmal for this approach to be considered. The feasibility of transaortic MVR should be explored in patients with bivalvular regurgitation resulting from other etiologic mechanisms such as rheumatic fever and endocarditis.
I 336
The Journal of Thoracic and Cardiovascular Surgery May 1994
Najafi and Hemp
It is safe to suggest that this approach, when feasible, may be desirable even in patients in whom the mitral valve can readily be excised and replaced through a conventional incision. To state this differently, in a patient with bivalvular disease the practicality of MVR through the aortic root (after excision of aortic leaflets) should be thoroughly examined before the surgeon commits to an atriotomy. This approach is particularly useful in patients who have previously undergone cardiac surgery. The transaortic approach obviates the need for release of adhesions surrounding the left ventricle. We acknowledge with great admiration the contributions of two previous reports on this subject.v" We also wish to increase the awareness of our colleagues and cautiously encourage the application of this undoubtedly underused approach to MVR in carefully selected patients. Ms. Elizabeth Wolff's efforts in preparing this report are greatly appreciated.
I.
2.
3.
4.
5.
REFERENCES Meyer BW, Verska JJ, Lindesmith GG, Jones Jc. Open repair of mitral valve lesions: the superior approach. Ann Thorac Surg 1965;1:453-7. Berrkklouw E, Hiisamettin E, Schoenberger JP. Combined superior-transseptal approach to the left atrium. Ann Thorae Surg 1991;51:293-5. Carmichael MJ, Cooley DA, Favor AS. Aortic and mitral valve replacement through a single transverse aortotomy: a useful approach in difficult mitral valveexposure. Tex Heart Inst J 1983;10:415-9. Crawford ES, Coselli JS. Marfan's syndrome: combined composite valve graft replacement of the aortic root and transaortic mitral valve replacement. Ann Thorac Surg 1988;45:296-302. Helseth HK, Haglin JJ, Stenlund RR, Peterson CR. Composite graft replacement of the aortic root and ascending aorta. Movie presented at the meeting of the Society of Thoracic Surgeons, January 17-19, 1983, San Francisco, California.