I operation may be necessary before infection is eradicated

Transcription

1 Results of Homograft Aortic Valve Replacement for Active Endocarditis Ishik C. Tuna, MD, Thomas A. Orszulak, MD, Hartzell V. Schaff, MD, and Gordon K. Danielson, MD Section of Cardiovascular Surgery, Mayo Clinic and Mayo Foundation, Rochester, Minnesota Since July 1985, cryopreserved homograft prostheses have been used for aortic valve replacement in 10 patients, aged 2 to 77 years, with active endocarditis. Five patients had positive bacterial cultures from excised valves, and all had clinical findings of uncontrolled infection while receiving appropriate antibiotics. Homograft valves (four) or valved conduits (six) were implanted for treatment of sepsis (6 patients), congestive heart failure (3) or recurrent emboli (1 patient), and complicating native (5 patients) or prosthetic valve (5) endocarditis. Staphylococci (6 patients), streptococci (31, and Cundidu (1) were infecting organisms. Preoperatively, Doppler echocardiography showed aortic regurgitation in all patients. At operation, 9 patients had gross vegetations, 9 had single or multiple abscess cavities, and 5 had pericarditis. Complex reconstruction of the aortic valve and annulus with homograft conduits was necessary in 6 patients (3 with previous aortoventriculoplasty). Two early deaths (ventricular failure, perioperative stroke) occurred. Mean follow-up of all operative survivors was 2.1 years (range, 0.6 to 3.6 years), and one late death resulted from arrhythmia. Homograft valve regurgitation increased in 1 patient, and 7 late survivors are asymptomatic. No patient has had recurrence of endocarditis. We conclude that cryopreserved homograft aortic valvehoot replacement is an effective method for management of active endocarditis complicated by annular destruction. (Ann Thorac Surg 1990;49:619-24) n both native and prosthetic aortic valve endocarditis, I operation may be necessary before infection is eradicated by antibiotic therapy. Valve replacement during this active phase of infection is required when sepsis is uncontrolled, when congestive heart failure resulting from valve insufficiency is severe and progressive, or when vegetations embolize despite optimal medical therapy. Often, patients with active infection have extensive annular destruction and perivalvular ring abscesses that complicate insertion of aortic valve prostheses. Several operative techniques for managing such problems have been proposed [l-141; this report reviews our recent experience with homograft valve replacement in patients with active aortic valve endocarditis. Material and Methods Patient Population From June 1985 through July 1988, 80 patients had aortic valve replacement using cryopreserved homograft valves. In 10 patients, the indication for operation was active endocarditis. These patients (all male) ranged in age from 2 to 77 years (mean age, 39 years); 5 patients had infection of their native aortic valve. Each of 5 patients with prosthetic valve endocarditis had undergone multiple prior cardiac operations (mean, 2.8 prior procedures), Presented at the Thirty-sixth Annual Meeting of the Southern Thoracic Surgical Association, Scottsdale, AZ, Nov 9-11, Address reprint requests to Dr Orszulak, Mayo Clinic, 200 First St SW, Rochester, MN including 3 who had prior aortoventriculoplasty (Konno- Rastan procedure) [15, 161. Symptoms, usually spiking fevers, were observed from 11 to 150 days (mean, 26 days) preoperatively, and bacteremia was subsequently documented by multiple (mean, seven) positive blood cultures in each patient. Causative organisms were staphylococci in 6 patients, streptococci in 3 patients, and Candida in 1 patient. All patients received antibiotics selected on the basis of culture results before operation, and duration of drug therapy ranged from seven to 70 days (mean, 22 days). Preoperative Doppler echocardiographic examination was performed in all patients; aortic regurgtation was graded as follows: none or trivial = 0, mild = 1, moderate = 2, and severe = 3. Preoperatively, mean grade of aortic regurgitation was 2.4. Echocardiographic-derived left ventricular ejection fraction ranged from 0.50 to 0.71 (mean, 0.63). Echocardiography showed valvular vegetations in 6 patients, and annular abscesses were identified preoperatively in 3 patients. Three patients had varying degrees of atrioventricular conduction disturbance. One patient with previous aortoventriculoplasty had complete heart block preoperatively and had a permanent transvenous pacemaker; 2 patients had first-degree heart block. In addition, 5 patients were in congestive heart failure; 2 had angina pectoris, and 1 had recently suffered myocardial infarction caused by coronary artery embolus. The primary indication for aortic valve replacement was persistent sepsis in 6 patients, progressive congestive heart failure in 3, and recurrent emboli in 1 patient. In by The Society of Thoracic Surgeons /90/$3.50

2 620 TUNAETAL Ann Thorac Surg 1990;49: Table 1. Patient Characteristics Duration of Preop White Preoperative Preoperative Blood Cell Patient Age Operative Antibiotics Temperature Count No. (yr) Previous Operations Indication Organism (days) ( C) (X 1,0001mL) 1 50 AVR (homograft), redo Sepsis Candida albicans AVR (Hancock) AVR (Braunwald- CHF Staphylococcus Cutter), repair of periprosthetic leak AVR (Starr-Edwards), Sepsis Staphylococcus redo AVR (Starr- Edwards), redo AVR (Konno, Bjork- Shiley) Aortic valvotomy, redo Sepsis Staphylococcus aortic valvotomy, AVR (homograft), redo AVR (Konno, St. Jude) Recurrent epidermidis Staphylococcus emboli CHF Streptococcus Aortic valvotomy, AVR Sepsis viridans Streptococcus (Konno, Bjork- Shiley) Sepsis pyogenes Streptococcus Sepsis viridans Staphylococcus CHF Staphylococcus AVR = aortic valve replacement; CHF = congestive heart failure. patients, acute hemodynamic collapse precipitated emergency aortic valve replacement. Patient characteristics are summarized in Table 1. Operative Course Standard cardiopulmonary bypass techniques were used, and duration of perfusion ranged from 125 to 344 minutes (mean, 210 minutes). Systemic hypothermia (mean perfusate temperature, 20 C) was used in all patients, and limited periods of circulatory arrest were required in 2. Multidose cold (crystalloid or blood) cardioplegia and topical cooling were used, and the period of aortic occlusion ranged from 92 to 194 minutes (mean, 135 minutes). Operative findings are shown in Table 2. Nine patients had valvular vegetations, 9 had annular abscesses, and 5 had pericarditis. Five patients subsequently had positive valve cultures, whereas 8 had organisms identified on Gram stain of valvular tissue or vegetations. The variety of defects in the annulus, aorta, and ventricular septum requiring reconstruction after debridement are summarized in Table 2. Goals of repair were (1) to provide a secure anchor for valve implantation, (2) to restore aortoventricular continuity, and (3) to exclude abscess cavities from the circulation. In 4 patients, these objectives were achieved by debridement and homograft valve implantation alone. In 6 patients, a homograft conduit was required, and 3 of these patients had additional defects repaired. Results Perioperative Course Two patients died early after operation; 1 patient had biventricular failure and could not be separated from cardiopulmonary bypass. Another patient suffered a fatal intracerebral hemorrhage from a mycotic aneurysm. Nonfatal complications included hemorrhage requiring reoperation in 1 patient and bacterial pneumonia in 3 patients. Duration of hospitalization ranged from nine to 49 days (mean, 29 days), with intensive care unit stays of two to 31 days (mean, nine days). Intravenous antibiotic therapy was usually continued during the postoperative hospitalization; 2 patients were discharged on long-term oral antibiotics. No patient had bacteremia postoperatively, and, on the average, eight blood cultures were obtained before the patient s dismissal. Early postoperative Doppler echocardiography showed only trivial or mild aortic homograft

3 Ann Thorac Surg 1990; TUNAETAL 621 Table 2. Operative Characteristics Patient No. Operative Findings Procedure Defect After Debridement 1 Prosthesis, multiple vegetations, large, penetrating annular abscess (NCC) 2 Dehisced prosthesis, multiple vegetations, annular abscesses (RCC, LCC) 3 Dehisced prosthesis, multiple vegetations, infected RVOT, VSD patches, purulent pericarditis, periaortic abscess Prosthesis, multiple vegetations, multiple annular abscesses (NCC, RCC, LCC) Bicuspid aortic valve, multiple vegetations, annular abscess (RCC), fibrinous pericarditis Bicuspid aortic valve, multiple vegetations, cusp perforation, annular abscess (NCC) Dehisced prosthesis, dehisced RVOT, VSD patches, multiple vegetations, annular abscess (NCC, LCC), infected pacemaker leads, purulent pericarditis 8 Bicuspid aortic valve, multiple vegetations, cusp perforation 9 Bicuspid aortic valve, multiple vegetations, annular abscesses (RCC, LCC), fibrinous pericarditis 10 Tricuspid aortic valve, cusp perforation, annular abscess (NCC), fibrinous pericarditis AVR with 23-mm homograft conduit, coronary ostial reimplantation AVR with 22-mm homograft valve, bypass graft to LAD, IABP AVR with 22-mm homograft conduit, VSD closure with anterior mitral leaflet of homograft, coronary ostial reimplantation, RVOT reconstruction with bovine pericardium AVR with 23-mm homograft conduit, coronary ostial reimplantation AVR with 20-mm homograft valve, exclusion of abscess with homograft AVR with 22-mm homograft valve AVR with 19-mm homograft conduit, VSD closure with side of homograft, coronary ostial reimplantation, RVOT reconstruction with bovine pericardium AVR with 18-mm homograft valve AVR with 29-mm pulmonary homograft conduit, exclusion of abscesses with conduit, coronary ostial reimplantation, IABP, bypass graft to LAD AVR with 25-mm homograft conduit, repair of aortic defect with conduit, IABP Annulus, aorta in NCC position Annulus, septum in RCC, LCC position VSD, RVOT, annulus and ascending aorta Annulus and ascending aorta Annulus, septum in RCC position VSD, RVOT, annulus and ascending aorta Septum in RCC, LCC position Annulus, aorta in NCC position IABP = intraaortic balloon pump; LAD = left anterior descending coronary artery; LCC = left coronary cusp position; NCC = noncoronary cusp position; RCC = right coronary cusp position; RVOT = right ventricular outflow tract; VSD = ventricular septa1 defect. regurgitation (mean grade, 0.6; Fig 1). At dismissal from the hospital, all patients were afebrile and had normal white blood cell counts. Lute Outcome Follow-up of operative survivors ranged from 0.6 to 3.6 years (mean, 2.1 years). One late death occurred in a patient whose sudden collapse appeared to result from arrhythmia; postmortem examination showed serious coronary atherosclerosis with no evidence of infection. Homograft valve regurgitation assessed by Doppler echocardiography increased in a single patient from mild to severe during 2.7 years of follow-up (see Fig 1). Seven late survivors are asymptomatic, and 5 of these patients are taking no cardiac medications. No patient has had evidence of recurrent endocarditis. Preop Postop Late Fig 1. Severity of aortic valve regurgitation determined by Doppler echocardiography preoperatively (Preop), postoperatively (Postop), and at last follow-up (Late). See text for description of grades of regurgitation. Open circles denote operative nonsurvivors. Comment Aortic valve endocarditis is usually managed with antibiotic therapy initially; under ideal circumstances, valve replacement is delayed until infection is eradicated [17, 181. When earlier operation is required, valve infection is

4 622 TUNAETAL Ann Thorac Surg 1990; Fig 2. Complex repairs such as aortic root replacement and ventricular septal defect closure can be managed with homograft conduit implantation using the anterior mitral leaflet for septa1 defect closure. With annular abscesses or proximal aortic root defects, a trimmed homograft conduit may be used, with the proximal suture line in a subaortic position (mitral annulus or ventricular muscle), below the level of such defects. frequently associated with extensive annular destruction and perivalvular ring abscesses [14, 191. A variety of techniques for exclusion or closure of valve ring abscess cavities have been proposed; small defects can be closed by direct suture, but patch closure with Dacron or pericardium is generally preferred [lo, 12, 141. Posterior valve ring abscesses create deficiencies in aortoventricular continuity, and closure of these defects with patches is necessary to anchor the valve prosthesis securely without distorting the anterior leaflet of the mitral valve. In patients with extensive annular destruction, aortic valve translocation, conduit replacement, and extraanatomical bypass have been reported [2,3, 6-9, 111. Cryopreserved homograft prostheses have theoretical and practical advantages in aortic valve replacement for active endocarditis [7,20]. First, it seems prudent to avoid use of nonbiological material in areas of bacterial or fungal contamination to minimize risk of reinfection. Data from Greenlane Hospital and others suggest that risk of early endocarditis after aortic valve replacement with homograft prostheses is substantially lower than with mechanical valves or heterografts [21, 221. A second important advantage of homograft valves is flexibility in using the contiguous aorta and anterior mitral valve leaflet to repair abscess cavities; the valve can be individually tailored to conform to adjacent defects. Extreme examples in this series were 2 patients who had infection of aortoventriculoplasties; in these patients, all infected prosthetic material was removed and the resulting defect in the interventricular septum was reconsti- Fig 3. The proximal suture line is made with homograft conduit inverted into the ventricle. The conduit is then everted into the remnant of the native aorta.

5 Ann Thorac Surg 1990;49: TUNAETAL 623 Although the present series is small, the absence of early or late reinfection encourages us to use cryopreserved homografts whenever possible for aortic valve replacement in active endocarditis. Further follow-up is necessary to determine whether late durability of homograft aortic valves will compare with that of other bioprostheses or mechanical valves. Fig 4. By placing the distal suture line above the level of any defects, the homograft may be used to reconstruct the proximal aorta and exclude annular abscesses from the circulation. Although the conduit may be scalloped to accommodate insertion of the coronay ostia (inset), we favor direct implantation of the corona y ostia into aortotomies and preservation of the sinus portion of the graft whenever possible. tuted with the anterior leaflet of the homograft conduit or by direct suture of the muscular portion of the valve annulus to the septum. We have used the cylinder technique for aortic valve replacement using pulmonary autografts and aortic valve homografts [23, 241. Figures 2, 3, and 4 show the operative technique. The sinus portion of the graft is left in place, thus preserving the natural orientation and distances between the valve commissures. Coronary ostia are sewn directly to 4- to 5-mm aortotomies. We believe that this method minimizes risk of central insufficiency. The cylinder technique was extremely useful in 3 patients in this series in whom the sleeve of homograft aorta between the upper and lower suture lines excluded abscess cavities. If a properly sized aortic homograft conduit is not available, we also consider the pulmonary autograft as an aortic valve substitute; the pulmonary valve may be replaced with a pulmonary homograft conduit. References 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: Donaldson RM, Ross DM. Homograft aortic root replacement for complicated prosthetic valve endocarditis. Circulation 1984;7O(Suppl 1):178. Reitz BA, Stinson EB, Watson DC, Baumgartner WA, Jamieson SW. Translocation of the aortic valve for prosthetic valve endocarditis. J Thorac Cardiovasc Surg 1981;81: Frantz PT, Murrary GF, Wilcox BR. Surgical management of left ventricular-aortic discontinuity complicating bacterial endocarditis. Ann Thorac Surg 1980;29:1-7. Zwischenberger JB, Shalaby TZ, Conti VR. Viable cryopreserved aortic homograft for aortic valve endocarditis and annular abscesses. Ann Thorac Surg 1989;48: Danielson GK, Titus JL,DuShane JW. Successful treatment of aortic valve endocarditis and aortic root abscesses by insertion of prosthetic valve in ascending aorta and placement of bypass grafts to coronary arteries. J Thorac Cardiovasc Surg 1974; Lau JKH, Robles A, Cherian A, Ross DN. Surgical treatment of prosthetic endocarditis. J Thorac Cardiovasc Surg 1984; Bove EL, Parker FB Jr, Marvasti MA, Randall PA. Complete extra-anatomic bypass of the aortic root: treatment of recurrent mediastinal infection. J Thorac Cardiovasc Surg 1983; 86: VanHooser DW, Johnson RG, Hein RA, Elkins RC. Successful management of aortic valve endocarditis with associated periannular abscess and aneurysm. Ann Thorac Surg 1986; 42: Bailey WW, Ivey TD, Miller DW Jr. Dacron patch closure of aortic annulus mycotic aneurysms. Circulation 1982;66(Suppl 1): Endo M, Nishida H, Imamura E, Koyanagi H. Sutureless aortic valve replacement for periannular abscess due to active bacterial endocarditis: a new translocation technique. Ann Thorac Surg 1988;45: Symbas PN, Vlasis SE, Zacharopoulos L, Lutz JF. Acute endocarditis: surgical treatment of aortic regurgitation and aortico-left ventricular discontinuity. J Thorac Cardiovasc Surg 1982;84: Frantz PT, Murray GF, Wilcox BR. Surgical management of left ventricular-aortic discontinuity complicating bacterial endocarditis. Ann Thorac Surg 1980;29:1-7. David TE, Komeda M, Brofman PR. Surgical treatment of aortic root abscess. Circulation 1989;8O(Suppl 1):26% Konno S, Imai Y, Iida Y, Nakajima M, Takuno K. A new method for prosthetic valve replacement in congenital aortic stenosis associated with hypoplasia of the aortic valve ring. J Thorac Cardiovasc Surg 1975;70: Rastan H, Koncz J. Aortoventriculoplasty: a new technique for the treatment of left ventricular outflow tract obstruction. J Thorac Cardiovasc Surg 1976;71:92& Wilson WR, Danielson GK, Giuliani ER, Geraci JE. Prosthetic valve endocarditis. Mayo Clin Proc 1982;5715%61.

6 624 TUNAETAL Ann Thorac Surg 1990;49:61% Croft CH, Woodward W, Elliott A, Commerford PJ, Barnard CN, Beck W. Analysis of surgical versus medical therapy in active complicated native valve infective endocarditis. Am J Cardiol 1983;51: Amett EN, Roberts WC. Valve ring abscess in active infective endocarditis. Circulation 1976; Okita Y, Franciosi G, Matsuki 0, Robles A, Ross DN. Early and late results of aortic root replacement with antibioticsterilized aortic homograft. J Thorac Cardiovasc Surg 1988; 95:69& Kirklin JW, Barratt-Boyes BG. Aortic valve disease. In: Kir- klin JW, Barratt-Boyes BG, eds. Cardiac surgery. New York: John Wiley, Matsuki 0, Robles A, Gibbs S, Bodnar E, Ross DN. Longterm performance of 555 aortic homografts in the aortic position. Ann Thorac Surg 1988;46: OBrien MF, McGiffin DC, Stafford EG. Allograft aortic valve implantation: techniques for all types of aortic valve and root pathology. Ann Thorac Surg 1989;48: Matsuki 0, Okita Y, Almeida RS, et al. Two decades experience with aortic valve replacement with pulmonary autograft. J Thorac Cardiovasc Surg 1988;95: DISCUSSION DR FRED H. EDWARDS (Washington, DC): Do you think it would have been possible to repair any of these valves? If not, could you comment on what role you think valve repair has in this clinical scenario? DR TUNA The patients with prosthetic valve endocarditis obviously required excision of their prostheses. Patients in this series with native valve endocarditis typically had extensive destruction of the leaflets and the annulus, with ring abscess formation; I do not think the valves would have been amenable in any manner to repair. DR GEORGE R. DAICOFF (St. Petersburg, FL): These are marvelous results in a very difficult group of patients, and I think you should be congratulated. I believe that the problem with homograft valve regurgitation in the patients in this series could be solved by using the entire cuff of aorta and reimplanting the coronary arteries. I realize that this is a bigger operation and perhaps a trade-off. But the incidence of regurgitation is much higher when a freehand graft is used, as much as 30% to 35% early, and there is the worry about progressive regurgitation. You had a very low incidence of increasing regurgitation. Do you have any comments about that? DR TUNA We would agree with you entirely. We did have increasing regurgitation in 1 patient who had had a freehand valve scalloped in the traditional manner. That is why we have moved toward use of a homograft conduit implanted within the native aortic remnant. We believe that maintaining the sinotubular relationships and the support structures of the leaflets may prevent early and late regurgitation occumng in these valves. Selecting the appropriate size homograft in these patients can be quite difficult when the root has been destroyed and the architecture is distorted. DR DAICOFF Based on that experience, do you think it is worthwhile, with the additional pump time, additional ischemia, and risk of implanting the coronary arteries, of doing this as a routine aortic valve replacement rather than for infected valves only? DR ORSZULAK. Additional time is required when replacing a standard aortic valve with a homograft. It takes longer than a conventional valve replacement. The patients presented here had extremely complex conditions. Although the bypass time was prolonged, some of these patients had to be placed on cardiopulmonary bypass before sternotomy. Thus, bypass time and cross-clamp time, because of the complexity, do not reflect the time required for standard homograft replacement. It is longer, but we believe it is justifiable in patients who are candidates for homograft. Use of a homograft may increase the required crossclamp time by perhaps 50% over that needed for standard prosthetic valve replacement.