I replacement was initiated in the early 1960s by Ross [l]

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1 Freehand Homograft Aortic Valve Replacement- The Learning Curve: A Technical Analysis of the First 31 Patients Ellis L. Jones, MD Division of Cardiothoracic Surgery, Emory University School of Medicine, Atlanta, Georgia The technique for implanting the homograft aortic valve is significantly more complex than that of either the bioprosthetic or mechanical valve. During development of the procedure, errors of technique were committed; a critical analysis of the learning experience is presented. In the initial 31 patients, the following problems were encountered: mitral stenosis secondary to inadequate debulking of the homograft (1 patient), prolapse of a single homograft leaflet necessitating valve replacement three days later (1 patient), incorrect homograft orientation with torsion in a calcified aorta necessitating subsequent replacement (1 patient), and aortic sinus perforation (thawing injury) (1 patient). In addition, another 4 patients had diastolic murmurs thought to be secondary to inadequate tension setting of the homograft commissural posts. From this experience, several important technical considerations for homograft replacement of the aortic valve were noted: use of interrupted subannular sutures; careful inspection for aortic perforation (thawing); extensive trimming of the homograft septum and mitral remnant; orientation of the homograft to the recipient aorta to obtain the best commissural and sinus alignment; selection of another type of valve if the size of the recipient annulus is greater than 27 mm; retention of the homograft sinus, which orients to the recipient noncoronary sinus (for a calcified aorta); and exaggerated tension on the homograft commissural posts before initiation of the second suture line. There has been 1 hospital death and no late deaths. Adherence to rigid principles of technique has resulted in no further valve replacements and no incidences of valvular leakage at early or late follow-up. (Ann Thorac Surg 1989;48:26-32) nterest in use of the homograft valve for aortic valve I replacement was initiated in the early 1960s by Ross [l] and Barratt-Boyes [2]. Since that time, several experienced surgeons [3-81 have advocated use of this valve as an equal, if not superior, choice for aortic valve replacement in young and older patients alike. To achieve clinical success, however, it is noteworthy that these same surgeons have spent considerable time in the development of a technique that assures excellent immediate and intermediate-term results [4-91. Although excellent results have been achieved and reported by these surgeons, a precise outline of implantation technique has been infrequently available [lo]. Careful processing and storage of the cryopreserved homograft valve has now made it immediately available to large numbers of surgeons, but past successful methods of implantation have been related more to technical artistry and experience than to specific step-by-step instruction. Without specific tutorial guidance from those having years of experience with freehand implantation techniques, potential problems can occur immediately or shortly after implantation; these necessarily dampen enthusiasm for what may prove to be an important and superior alternative for aortic valve replacement. Presented at the Thirty-fifth Annual Meeting of the Southern Thoracic Surgical Association, Marco Island, FL, Nov 10-12, Address reprint requests to Dr Jones, Emory Clinic, 1365 Clifton Rd, NE, Atlanta, GA The purpose of this report is to present a detailed technical analysis of my initial experience using the cryopreserved homograft valve in the aortic position with special emphasis on difficulties encountered during the learning curve for freehand implantation. Material and Methods Over the past 18 months, 31 cryopreserved homograft aortic valves (CryoLife Laboratories, Marietta, GA) have been implanted freehand by me at Emory University Hospital. There were 22 male and 9 female patients with a mean age of 50 years. The range of valve sizes is shown in Table 1. Aortic valve replacement was performed for aortic stenosis in 14 patients, aortic regurgitation in 11 patients, and combined aortic stenosis and aortic regurgitation in 6 patients. Two patients had prior coronary artery bypass grafting and 1 patient, a previous porcine bioprosthetic aortic valve replacement. Freehand homograft aortic valve replacement was performed with coronary artery bypass grafting in 3 of the patients and for healed endocarditis in 3 patients. In 2 patients, aortic root enlargement through the noncoronary sinus was combined with homograft valve replacement. Technique of Operation Because of the increased time required to perform the operation, superior myocardial preservation becomes extremely important. To accomplish these goals, bicaval by The Society of Thoracic Surgeons /89/$3.50

2 Ann Thorac Surg 1989;48:26-32 JONES 27 HOMOGRAFT AORTlC VALVE REPLACEMENT Table 1. Distribution of Valve Sizes in 31 Patients Valve Size (mm) No. of Patients 17" a Two patients had noncoronary sinus root enlargement with glutaraldehyde-treated pericardium. cannulation, systemic hypothermia to 21" to 25"C, and frequent administration of 4 C crystalloid cardioplegia are used. A standard "hockey-stick" aortotomy incision into the noncoronary sinus with removal of all annular and subannular calcium is performed. The aortic incision is planned to avoid any area of the aorta where commissural sutures will be placed. The diameter of the aortic annulus and the transcommissural diameters are measured to a tight fit with a disc sizer, and a homograft 3.0 mm smaller than the diameter of the annulus is thawed while interrupted pledgeted 3-0 sutures are inserted. These sutures are placed approximately 3.0 mm below the native annulus but in such a manner as to avoid the conduction system and the body of the anterior mitral valve leaflet. At these two levels, the sutures are moved back to the level of the native annulus. The subannular sutures are also placed low enough to avoid encroachment on the coronary ostia (Fig 1). I and others [4, 6, 101 believe that interrupted sutures for the proximal row allow better exposure and less chance for homograft malrotation than the continuous suture technique. Preparation of Homograft Once thawed, the homograft should be carefully inspected under magnification for intimal and medial tears that may become manifest at the time of warming. Any abnormality of the sinuses must also be noted, with particular attention paid to potential cusp prolapse. Next, the anterior mitral leaflet and then the septum of the homograft are carefully trimmed to a perfect cylinder 3 to 4 mm in width (Fig 2). The homograft septum is debulked thoroughly and the homograft aorta divided distally 1 cm above the commissural attachments. Only two of the three homograft sinuses are scalloped approximately 3 mm above the annulus in a U, not V, shape. This scalloping can be more precisely performed prior to insertion of the homograft into the aortic root, where manipulation and visibility are more limited. The sinus oriented to the recipient noncoronary sinus is not scalloped; this is particularly helpful when aortic wall calcification is dense at the lower portion of the sinus or when it is desirable to use the homograft noncoronary sinus wall to conform symmetrically to the recipient aorta, thereby maintaining the cylindrical configuration of the entire homograft unit. The latter technique is useful when the recipient noncoronary sinus is thinned and degenerative and in need of reinforcement. As a useful general guide, the depth of the scallop will be determined by the distance between the coronary ostia and the proximal suture line. Orientation of Homograft Although orientation of the anterior mitral leaflet of the homograft to the recipient septum gives the most even distribution of bulk within the annulus, the most versatile approach is to orient the homograft to whatever position gives the best commissural alignment. Orientation of the homograft mitral remnant to the left main coronary artery minimizes any bulky septa1 impingement on the ostium. If the transcommissural diameter (at the sinotubular ridge) is slightly smaller than the homograft aortic wall, orientation of the largest homograft sinus toward the recipient left sinus (which is usually long) allows any excessive circumference of the homograft aortic wall to be distributed evenly on either side of the left main coronary artery and into the noncoronary sinus. Although these guidelines are potentially helpful and should be appreciated, the most frequent practice has been to orient the homograft in the most natural position, ie, left sinus of the homograft to the left sinus of the recipient. Once oriented, the homograft is inverted (by pushing the commissural posts centrally) so that the leaflets occupy an external position (Fig 3). This maneuver is 9erformed to enhance visibility when passing the subannular 3-0 sutures into the muscular and fibrous base of the homograft valve. The homograft is lowered into position, but before the individual sutures are tied, the commis- Fig 1. Placeinent of sirbaiiizrrlar sutures below plane of left and right coronary ostia.

3 28 JONES Ann Thorac Surg 1989;48:2&32 Fig 3. (A) In7lersiorz of hoino~yraft so that leaflets are external and readihy zlisible. (B) Honio,graft ns it appears in left ventricular cavity as siitiires are tied. Fig 2. (A) Trimming anterior leaflet of the mitral valve and septum 3 to 4 mm below the homograft leaflets. (B) Debulking the septa/ rniiscle remnant. (0 U-shaped scallop of left and right sinuses OJI/!/; thus retaining aortic wall, which orients to recipient noncoronary sinrrs. Anatomical Variations When there is a marked discrepancy between the aortic annulus diameter (small) and the body surface area of the patient (large), and aortic annulus enlargement is indicated, the homograft can still be used with a modification of the technique of Manouguian and Seybold-Epting [ll]. The aortotomy incision is carried down into the anterior leaflet of the mitral valve, and a generous portion of glutaraldehyde-treated pericardium is used to expand the native annulus to the desired homograft size (Fig 6). The annulus is sized, canting the disc sizer into the patch and sural posts are temporarily everted to check for suture entrapment. Once the sutures are tied, the valve is everted from the ventricle (Fig 4), and tension is set on the commissural posts, thus elevating the homograft commissures to a plane approximately 5 mm above the top of the native commissural attachments (Fig 5). This latter maneuver avoids leaflet prolapse under diastolic pressure once the operation has been completed. The direction of force applied to the commissural posts is that of the native commissures. A second row of sutures (4-0 Prolene, RB-1; Ethicon, Inc, Division of Johnson & Johnson, Somerville, NJ) evenly distributes the homograft throughout the circumference of the aorta. Fig 4. EZJC~S~OII of i d 7 fronr ~ left zmtricle.

4 Ann Thorac Surg 1989;48:2f3-332 JONES 29 Fig 5. (A) Teinporary tractioii sutitres elevate hornograft coiiriirissirml posts above and in line with native coinmissures. (B) Reterition of iioncoronary sinus of hoiirograft to niaintain c!/liiidrical confipratioii. (C) Coinpletion of second row of sutures, zihich even!y distribirtes homograft throughout the aortic circtiiiifereiice. marking the "new, expanded" pericardium with an ink pen. The interrupted 3-0 sutures are then passed through the pericardium at this level, and the suture line is completed in both the native and expanded pericardial annulus (Fig 7). The homograft valve is then inserted as described previously (Fig 8). Results There has been 1 death among the 31 patients for a combined early and late mortality of 3.2%. The patient died on the seventh postoperative day of an arrhythmia thought not to be related to the homograft valve. The patient was to be discharged from the hospital the following day. Explantation of the homograft was necessary in 5 patients, in 2 immediately and in 3 at 3, 8, and 37 days after implantation. In the 2 patients requiring immediate explantation, the reason was impairment of mitral valve function (restriction of anterior leaflet motion with left atrial pressure changes of mitral stenosis) in 1 patient and unacceptable aortic insufficiency after implantation of a 26-mm homograft into an aortic annulus 29-mm in diameter in the other. In 1 patient, a 23-mm homograft valve was explanted four days after implantation. The valve was preserved on removal and subsequently demonstrated prolapse of the noncoronary cusp when tested under hydrostatic pressure. Another patient required replacement of the homograft with a mechanical valve eight days after implantation. The 25-mm homograft demonstrated perfect apposition of the leaflets when the valve was viewed in the collapsed state, but was clearly leaking under diastolic pressure. The original reason for insertion of the homograft was to replace a failed 29-mm porcine bioprosthesis. In the final patient who required removal of the homograft (at 37 days), partial dehiscence of the valve, which was implanted into a heavily calcified aorta and annulus, developed. Torsion from malalignment of the homograft was also thought to be responsible.

5 30 JONES Ann Thorac Surg 1989;48:2&32 Fig 6. Technique employed for expanding aortic root diameter using pericardial gusset when annulus is hypoplastic. See text for details. Comment Freehand aortic homograft implantation in the subcoronary position was introduced by Ross [l] in 1962 and used subsequently by Barratt-Boyes [2] in Experience was limited to very few centers because of complex problems with availability, procurement, and preservation, difficulty of insertion, reports of early failures, and availability of satisfactory alternative bioprostheses [6, 8, 12-15]. Fig 7. Determining nezu plane of mlve and placement of sutures when aortic annulus is enlarged into noncoronary sinus and anterior leaflet of nlitrfll Recent interest in freehand homograft replacement of the aortic valve has been generated by several factors: the suggestion that cryopreserved valves contain living cells

6 Ann Thorac Surg 1989;48:26-32 JONES 31 Fig 8. Final orientation of homograft in expanded aortic root. (fibroblasts) of donor origin a time long after valve implantation; development of effective procurement, preservation, and distribution techniques; and reports that long-term durability of efficiently procured antibioticsterilized cryopreserved valves in a variety of sizes is substantially better than predicted in early reports and may approach an actuarial 10-year freedom from degeneration of close to 90% once technical problems of insertion have been overcome [4, 6, 7, 9, 121. In addition, worldwide experience has demonstrated that thromboembolism is almost nonexistent with a homograft valve and that the incidence of endocarditis after implantation of such a valve is the lowest among all valve choices for heart valve replacement [5, 71. It is the valve of choice for the treatment of active endocarditis [16]. In spite of improved procurement and availability, quantities are not yet sufficient to allow ABO or Rh compatibility matches between donor valve and recipient. Blood group mismatch has not been associated with a higher incidence of tissue failure to date, but as tissue preservation techniques improve, this might become a problem in the future [6, 7, 171. Before meaningful actuarial curves of valve degeneration, freedom from reoperation, or freedom from valverelated death can be constructed, freedom from technical problems related to the operative procedure must be achieved. Important aspects of the learning curve that are worthy of emphasis include accurate sizing of both the diameter of the annulus and the transcommissural diameter in the recipient aorta, interrupted subannular pledgeted sutures, and extensive debulking of the homograft. Whenever the transcommissural diameter of the recipient is substantially larger than that of the aortic annulus or the homograft itself, others (9, 14, 15, 181 have suggested aortic root tailoring procedures. Barratt-Boyes and associates [9] performed this in 7.5% of patients in an early series. In the patients so treated, the aortic root was excessively large in proportion to the homograft diameter. At the Southampton hospital in England, Virdi and coworkers [14] performed aortic root tailoring in 53% of 200 patients having freehand homograft aortic valve replacement. However, early diastolic murmurs were quite frequent (28%) among patients having a tailoring procedure, and Virdi and co-workers recommended avoiding the homograft if the diameter of the recipient annulus was greater than 24 mm. The incidence of aortic regurgitation in patients having alteration (plication or excision of a strip of aortic wall) of the noncoronary sinus was also increased in the series reported by Thompson and colleagues [15]. Miller and Shumway [6] used extra material to expand the aortic root in 30% to 40% of patients in their series. In either case, whether there is plication of a large aortic root or placement of a gusset in the small aortic root, the primary objective is to maintain the cylindrical size and shape of the noncoronary sinus to prevent distortion of the homograft, poor leaflet coaptation, and subsequent aortic regurgitation. Although excellent clinical surgeons still effectively use a continuous suture technique for the proximal subannular attachment of the homograft [7, 9, 161, Matsuki and associates [5], as well as Moreno-Cabral and co-workers [lo], believe that use of interrupted sutures for the lower suture line dramatically reduces the incidence of technical failure due to malrotation. For this reason, as well as improved exposure and more secure placement, I also have used the interrupted technique. Extensive debulking of the homograft while avoiding perforation of the muscle remnant or encroachment on the homograft leaflets is important to prevent excessive tissue in and around the coronary ostia (Fig 9). If the amount of retained septa1 muscle is extreme, impairment of mitral valve function can also occur, resulting in clinical mitral stenosis (Fig 10). Technically successful implantation also depends on precise scalloping of two homograft sinuses only (retaining the noncoronary sinus), inversion of the ho- Fig 9. Inadequate debulking of septum can produce encroachment on coronary ostia with obstruction.

7 32 JONES Ann Thorac Surg 1989:48:26-32 excessively dilated. Although Barratt-Boyes and coworkers [9] have stated this occurs when the aortic annulus diameter is greater than 30 mm, this approach requires great experience and knowledge of aortic root tailoring procedures with their known disadvantages. In my opinion, an alternative valve should be selected whenever the aortic annulus diameter is greater than 27 mm provided at least a 25-mm homograft is readily available. The experience in two of the five instances of failure lends support to this recommendation. Fig 10. Retained excessive bulk of homograft muscle can prodtice impairment of mitral valve function. mograft so that the leaflets are externally visible, setting excessive tension on the homograft commissural post above that of the native commissural attachment, and avoiding use of the homograft valve altogether when excessively large roots are encountered. By retaining the noncoronary sinus, the spatial relationships of the other commissures are maintained, preserving the beneficial cylinder so important in avoiding valvular regurgitation [4]. Miller and Shumway [6] retain the noncoronary sinus for use as a gusset to keep the spatial relationship of the commissures. With inversion of the homograft wall, the aortic leaflets are external and are more easily protected from injury from the 3-0 needle. Exaggeration of the tension on the homograft commissural posts above the normal commissural attachments prevents prolapse of the leaflets into the ventricle once a diastolic load is imposed on the cusp edges (Fig 11). Finally, there are anatomical conditions that dictate selection of an alternative valve substitute, and this most commonly arises when the aortic root of the recipient is Fig I I. If tension on homograft cornnzissural posts is not exaggerated above (approximately 5.0 inin) native commissural attachinent, prolapse of leaflets uiith aortic regrirgitation can occrir. References 1. Ross DN. Homograft replacement of the aortic valve. Lancet 1962;2: Barratt-Boyes BG. Homograft aortic valve replacement in aortic incompetence and stenosis. Thorax 1964;19: Ross DN. Replacement of aortic and mitral valve with a pulmonary autograft. Lancet 1967;2:95fS. 4. Ross D. Application of homografts in clinical surgery. J Cardiac Surg 1987;1(Suppl): Matsuki 0, Robles A, Gibbs 5, Bodnar E, Ross DN. Longterm performance of 555 aortic homografts in the aortic position. Ann Thorac Surg 1988;46: Miller DC, Shumway NE. "Fresh" aortic allografts: long-term results with free-hand aortic valve replacement. J Cardiac Surg 1987; 1 : O'Brien MF, Stafford EG, Gardner MAH, Pohlner PG, McGiffin DC. A comparison of aortic valve replacement with viable cryopreserved and fresh allograft valves, with a note on chromosomal studies. J Thorac Cardiovasc Surg 1987; 94: O'Brien MF, Stafford G, Gardner M, et al. The viable cryopreserved allograft aortic valve. J Cardiac Surg 1987; l(suppl): Barratt-Boyes BG, Roche AHG, Subramanyan R, Pemberton JR, Whitlock RML. Long-term follow-up of patients with the antibiotic-sterilized aortic homograft valve inserted freehand in the aortic position. Circulation 1987;75: Moreno-Cabral CE, Miller DC, Shumway NE. A simple technique for aortic valve replacement using freehand allografts. J Cardiac Surg 1988;3: Manouguian 5, Seybold-Epting W. Patch enlargement of the aortic valve ring by extending the aortic incision into the anterior mitral leaflet. J Thorac Cardiovasc Surg 1979; 78: Kirklin JW, Barratt-Boyes BG. Aortic valve disease. In: Kirklin JW, Barratt-Boyes BG, eds. Cardiac surgery. New York: John Wiley & Sons, 1986: Angell WW, Angell JD, Oury JH, Lamberti JJ, Grehl TM. Long-term follow-up of viable frozen aortic homografts. A viable homograft valve bank. J Thorac Cardiovasc Surg 1987;93: Virdi IS, Monro JL, Ross JK. Eleven year experience of aortic valve replacement with antibiotic sterilized homograft valves in Southampton. Thorac Cardiovasc Surg 1986;34: Thompson R, Yacoub M, Ahmed M, Somerville W, Towers M. The use of "fresh' unstented homograft valves for replacement of the aortic valve. Analysis of 8 years' experience. J Thorac Cardiovasc Surg 1980;79: Kirklin JK, Kirklin JW, Pacific0 AD. Aortic valve endocarditis with aortic root abscess cavity: surgical treatment with aortic valve homograft. Ann Thorac Surg 1988;45: Clark DR. Discussion of Angell et a1 ( Barratt-Boyes BG. A method for preparing and inserting a homograft aortic valve. Br J Surg 1965;52: