Surgical Management of Left Ventricular–Aortic Discontinuity Complicating Bacterial Endocarditis

ORIGINAL ARTICLES

Surgical Management of Left Ventricular- Aortic Discontinuity Complicating Bacterial Endocarditis Paul T. Frantz, M.D., Gordon F. Murray, M.D., and Benson R. Wilcox, M.D.

ABSTRACT Successful hemodynamic repair of left ventricular-aortic discontinuity complicating bacterial endocarditis in 2 patients was achieved using a composite valve-woven Dacron tube graft. The prosthetic valve was sutured without tension into the remaining aortic annulus, ventricular muscle, and base of the aortic leaflet of the mitral valve. Use of the composite graft allows adequate debridement of the abscess, restores ventricular-aortic continuity, excludes the abscess wall from systemic pressure, and does not require saphenous vein coronary bypass. Total exclusion of the aortic root, as described, is a lifesaving alternative repair in the care of desperately ill patients with this condition.

bacterial endocarditis in 2 patients using a composite prosthetic valve-Dacron tube graft. Use of the composite graft allows adequate debridement of the abscess, restores ventricularaortic continuity, and does not require saphenous vein coronary bypass. Case Reports Patient 1

A 22-year-old man was known to have had a heart murmur since childhood. Evaluation was prompted by two near syncopal episodes. There was a harsh grade 4/6 systolic murmur, and the electrocardiogram showed left ventricular hypertrophy. Moderate cardiomegaly Abscess of the aortic root complicating bacterial was demonstrated roentgenographically. Carendocarditis presents a relatively rare but for- diac catheterization revealed aortic stenosis midable challenge for the cardiac surgeon. with a valve area of 0.9 cm2and elevation of left Management of these lesions is difficult due to ventricular end-diastolic pressure to 15mm Hg. extensive tissue destruction associated with At operation on January 10, 1978, the aortic loss of supportive tissue in the aortic annulus valve was found to be bicuspid and partially and eventual left ventricular-aortic discon- calcified. The diseased valve was replaced with tinuity. Direct suture repair and valve replace- a No. 18 Lillehei-Kaster prosthesis. The postment often fail for this reason. Alternative sur- operative recovery was uneventful. Before the gical approaches dealing with aortic root patient’s discharge, one of the three postoperaabscess include repair of aortic and myocardial tive blood cultures grew Staphylococcus epiderdefects with Teflon felt in conjunction with midis, Clinical manifestations of endocarditis valve replacement [181, insertion of the were absent, and the staphylococcus was prosthetic valve in the ascending aorta and thought to be a contaminant. Subsequent blood placement of bypass grafts to the coronary ar- cultures grown when he was an outpatient were teries [13], and the use of a Dacron felt poly- sterile. propylene bolster to reinforce the cbsure of an Four months later, the patient was reaortic root abscess [30].This report describes admitted to North Carolina Memorial Hospisuccessful hemodynamic repair of left tal with complaints of fever, cough, weakness, ventricular-aortic discontinuity complicating and insomnia. A regurgitant aortic murmur was heard. Cardiac fluoroscopy demonstrated From the Department of Surgery, School of Medicine, Uni- excessive movement of the prosthetic valve. versity of North Carolina, Chapel Hill, NC. Multiple blood cultures again grew StaphylAccepted for publication Apr 20, 1979. ococcus epidermidis . Treatment with Kefzol Address reprint requests to Dr. Frantz, Clinical Sciences Building 229-H, University of North Carolina, Chapel Hill, (cefazolin sodium), gentamicin, and rifamNC 27514. pin was initiated. Cardiac catheterization re1

0003-49751801010001-07$01.25@ 1978 by Paul T.Frantz

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Fig 1. Extensive annular and subannular abscess associated with prosthetic valve dehiscence. Destruction of the aortic wall has extended to the ostium of the left coronary artery.

Fig 2 . Defect is repaired with reimplantation of both coronary arteries into the side of the graft.

vealed 3+ paraprosthetic regurgitation through a large posterior aortic root abscess. The prosthetic valve was separated from the annulus posteriorly and prolapsed into the left ventricle during diastole. Urgent reoperation was undertaken. The heart was exposed through a median sternotomy, and cardiopulmonary bypass was established with femoral arterial perfusion and cannulation of the venae cavae. Myocardial protection was afforded by core hypothermia, topical iced saline solution, and periodic infusion of potassium cardioplegic solution (4°C) directly into the coronary ostia. The prosthetic valve had detached from the aortic root posteriorly and laterally, and the sewing ring was covered by friable granulation tissue. When the prosthesis was removed, an extensive subannular abscess, which had destroyed the left and noncoronary sinuses, was uncovered. The aortic wall above the left sinus was destroyed within 2 mm of the inferior aspect of the left coronary ostium (Fig 1). The false aneurysm was debrided in an effort to remove all nonviable and infected tissue. The left atrial wall and the base of the pulmonary artery were exposed through the defect in the aortic root. Direct suture repair of the discontinuity between the left ventricle and aorta in conjunction with valve replacement was considered to be

impossible. Reconstruction was accomplished with a composite graft incorporating a No. 18 Lillehei-Kaster valve in a 30 mm woven Dacron tube graft. The composite prosthesis was sutured to the base of the heart with pledgeted horizontal mattress sutures through ventricular septum, ventricular wall muscle, and mitral valve. The coronary ostia were sutured into the side of the graft. The distal end of the graft was sutured into the lumen of the aorta, and the aortotomy was closed over the graft (Fig 2). Postoperative recovery was satisfactory except for a brief period of heart block, which resolved. Intraoperative cultures of the prosthetic valve and abscess were sterile, and gram stains failed to demonstrate bacteria. The patient completed a six-week course of Kefzol, gentamicin, and rifampin and is currently on a regimen of Septra (trimethoprim and sulfamethoxazole), administered orally. Six months after the second operation, the patient is free from infection and has resumed normal activities. Pa tien t 2 A 67-year-old man had mild, long-standing aortic insufficiency and stenosis. Four weeks prior to his admission, oral administration of erythromycin was started because of a productive cough and a right lower lobe pulmonary

3 Frantz, Murray, and Wilcox: Left Ventricular-Aortic Discontinuity

infiltrate. Two weeks later he was admitted to another hospital because of lethargy, fever, and chills. No congestive heart failure was noted. All blood and urine cultures grew Citrobacter freundii. Despite a two-week course of gentamicin, nafcillin, and carbenicillin, he continued to be febrile, and first-degree heart block and right bundle-branch block developed. The patient was transferred to North Carolina Memorial Hospital on May 20, 1978, and was found to be in mild congestive heart failure. Blood pressure was 115/35 mm Hg with Corrigan’s pulses, and a loud murmur of aortic insufficiency was noted. Blood cultures were sterile. Complete heart block developed, and a temporary pacemaker was inserted. Congestive heart failure increased despite intensive medical therapy. Cardiac catheterization revealed 4+ aortic insufficiency and a large abscess involving the aortic root. A fistulous communication between the abscess and right ventricle was also present. Further hemodynamic deterioration occurred, and operation was undertaken on May 26, 1978. The heart was exposed through a median sternotomy, and cardiopulmonary bypass was established with arch perfusion and cannulation of the venae cavae. Myocardial protection was afforded by core hypothermia, topical iced saline solution, and periodic coronary perfusion with potassium cardioplegic solution (4°C). Aortotomy revealed the right and noncoronary leaflets to be damaged and covered by exuberant vegetations. An abscess had replaced the aortic wall of the noncoronary and right sinuses of Valsalva, thereby creating left ventricular-aortic discontinuity in this area (Fig 3). The base of the pulmonary artery was exposed, and a communication existed between the abscess and the right ventricle through the interventricular septum. The valve was excised and the abscess debrided in an effort to remove all infected and nonviable tissue. Approximation of the left ventricle to the aorta by a direct suture technique was considered to be impossible. Thus, the aortic root was reconstructed with a composite No. 18 Lillehei-Kaster valve-30 mm woven Dacron graft conduit. The composite prosthesis was sutured to the remaining interventricular

Fig 3 . Destruction of the annulus and superior portion of the interventricular septum has resulted in ventricular-aortic discontinuity.

Fig 4 . The composite graft is sutured to the remaining healthy interventricular septum and the base of the aortic leaflet of the mitral valve.

septum, aortic annulus, and mitral valve with horizontal pledgeted mattress sutures. Two 5-mm circular openings were cut from the graft corresponding to the coronary ostia, which were sutured directly to the graft. The distal end of the graft was sutured within the aorta (Fig 4), and the aorta was closed over the graft. The patient was weaned from cardiopulmonary bypass, but complete heart block persisted and necessitated external pacing. Cultures of the valve and contents of the abscess cavity were sterile, and microscopic ex-

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amination of the debrided tissue revealed no organisms. The postoperative course was complicated by progressive mental deterioration, renal failure, and gastrointestinal bleeding. Throughout this period until the patient’s death on the tenth postoperative day, blood cultures remained sterile and no regurgitant murmurs appeared. Postmortem examination revealed the composite graft to be intact. A small, localized area of muscle necrosis was present in the interventricular septum at the base of the graft. This area contained inflammatory cells and fibrin, but no bacteria were present.

Comment The pathophysiology of acute bacterial endocarditis has changed dramatically during the past forty years. Prior to the introduction of antibiotic therapy, the mortality was quite high [251. Generally, patients with this disease died of septic complications of the infection before hemodyTamically significant valve lesions developed. The introduction of penicillin dramatically changed the outlook for patients with bacterial endocarditis. Frequent bacteriological cures with penicillin therapy were reported [lo, 151. The appearance of regurgitant lesions during antibiotic therapy became more common and carried grave prognostic implications [9, 28, 31, 401. The increasing incidence of heart failure from valve insufficiency was due to the elimination of early infectious deaths by antibiotics, the frequency of endocarditis caused by more virulent pathogens, and the prolongation of the inflammatory process by inadequate antibiotic therapy [35]. As reported by Wallace and co-workers [42] and later by Wilcox and associates [451, successful valve replacement in the presence of active endocarditis was possible. This experience provided the next major advance in the treatment of patients with this condition. Under the protective umbrella of high doses of antibiotics, removal of infected valves and granulation tissue is possible with a low incidence of prosthetic valve endocarditis and an acceptable incidence of paraprosthetic regurgitation [4,5,12, 18, 27, 29, 34, 39, 44, 47, 501. Endocarditis caused by antibiotic-resistant strains of bacteria

and fungi has been eradicated by excision of the infected site and valve replacement or repair of the intracardiac defect [21, 26, 33, 471. Operative mortality and long-term prognosis for patients with endocarditis confined to the valve leaflets are determined largely by the myocardial reserve at the time of operation [8, 27, 501. Timely surgical intervention should prevent extension of the valve infection to the aortic root [121. However, some patients are seen late in the course of the disease or have endocarditis due to a particularly virulent and invasive organism 1333. Extension of the infection to the aortic root with the formation of annular abscesses, aneurysms, or intracardiac fistulas significantly increases the incidence of surgical morbidity and mortality 1441. Prosthetic valve endocarditis is another cause of potentially lethal aortic root abscess. The annual incidence is less than 1% in patients with prosthetic heart valves; however, with the large number of patients at risk, this complication is significant [14, 22, 38, 491. Infection is commonly present within the sewing ring of the valve [2]. Spread of the infection from the sewing ring to the adjacent annulus increases the likelihood of abscess formation and prosthetic valve dehiscence [2, 171. The most common pathogen in these patients is staphylococcus, an organism that is highly destructive and difficult to eradicate when established on foreign material [l,2, 17, 341. Traditional surgical management for an abscess dictates removal of all foreign material from the infected site, debridement of nonviable tissue, thorough irrigation, and external drainage when possible. Unfortunately, an abscess within the aortic root often compromises strict adherence to these steps. Destruction of the fibrous tissue support within the aortic root reduces the amount of healthy tissue available for reconstruction by the usual surgical techniques. Although debridement and primary suture closure of a small aortic root abscess is possible in conjunction with valve replacement [19, 37, 441, larger abscesses associated with loss of annular fibrous tissue provide a more difficult management problem, as the remaining tissue is not suitable for suture placement.

5 Frantz, Murray, and Wilcox: Left Ventricular-Aortic Discontinuity

Attempted surgical repair is commonly complicated by paraprosthetic leak and dehiscence of the prosthetic valve [8, 16, 19, 37, 44, 461. Several innovative techniques have been used to repair aortic root defects due to bacterial endocarditis. Hatcher and associates [18] successfully repaired a ventricular septal defect with a Teflon felt patch in conjunction with an aortic valve replacement in a patient with annular and septal abscesses. Replacement of a necrotic portion of the aortic wall with a Teflon felt patch and aortic valve replacement was required in 2 other patients. Danielson and associates [13, 481 described implanting the prosthetic aortic valve in the ascending aorta. The coronary ostia were closed and reversed autogenous saphenous vein grafts sutured to the aorta above the prosthetic valve and to the right and left coronary artery systems. Whereas this technique obviates reimplanting a prosthetic valve into an infected annulus and promotes healing of the aortic root abscess, the wall of the subannular pseudoaneurysm is unprotected from systemic pressure, and expansion of the aneurysm may occur [13, 481. Gradual expansion and rupture of mycotic aneurysms in the aortic root have been reported [l, 6, 11, 32, 411. Furthermore, young patients whose myocardium is totally dependent upon reversed saphenous vein coronary bypass, are at risk for graft closure and myocardial infarction for many years. Olinger and Maloney [30] reported the use of a Dacron felt-polypropylene sponge bolster to reinforce the repair of left ventricular-aortic discontinuity complicating bacterial endocarditis. The bolster was designed to distribute the tension of the sutures and reduce the chance of dehiscence of the repair under these circumstances. An experimental technique of extraanatomical bypass of the aortic root was reported by Brown and colleagues [7]. A valve-containing conduit was inserted between the apex of the left ventricle and the descending thoracic aorta of a dog. A reversed autogenous saphenous vein graft was then interposed between the descending thoracic aorta and left anterior descending coronary artery. The ascending aorta was occluded with a clamp, thereby establish-

ing hemodynamic bypass of the aortic root. This technique allows removal of an infected aortic valve or prosthesis and permits debridement of an aortic root abscess without requiring insertion of a second prosthesis in the same area. In a human, however, closure of a friable, infected aortic root exposed to systemic pressure would be required. Coronary artery bypass grafting and placement of an apicoaortic conduit would also have the disadvantage of adding length and complexity to the operative procedure. Composite prosthetic valve-Dacron tube graft reconstruction of the aortic root, as described here, has previously achieved successful surgical repair of annuloaortic ectasia [3, 23, 24,36,43], ascending aortic aneurysm [24], and chronic aortic dissection with aortic valve involvement [24]. Use of the composite graft for repair of extensive aortic root abscess with left ventricular-aortic discontinuity has several attractive advantages not offered by other techniques. Debridement of the abscess and infected valves can be performed without the concern to leave sufficient tissue for direct suture approximation of the aorta and left ventricular muscle. The valve is sutured without tension directly into the remaining aortic annulus, ventricular muscle, and base of the aortic leaflet of the mitral valve. The remaining abscess wall is protected from systemic pressure by the Dacron graft, preventing gradual expansion and rupture of the aneurysm. The coronary ostia and the remaining rim of healthy aorta can be sutured to the graft in a fashion that prevents tension on the sutures and possible distortion of the coronary arteries. Hemostasis is assisted by suturing the composite graft within the lumen of the aorta and closure of the aorta over the graft. Coronary bypass is not required in this repair, avoiding potential late morbidity associated with the use of saphenous veins. The procedure can be done rapidly during a single period of ischemic arrest with potassium cardioplegic myocardial protection, an important feature in the care of these desperately ill patients. Successful hemodynamic repair of large aortic root defects was achieved in both patients

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reported here. Long-term success with composite prosthetic valve-graft reconstruction will depend on the incidence of graft infection. Past experience has shown that valve replacement in the presence of active endocarditis is possible without contamination of t h e prosthesis [4, 16,

11. Chesler E, Korns ME, Porter GE, et al: False aneurysm of the left ventricle secondary to bacterial endocarditis with perforation of the mitral-aortic intervalvular fibrosa. Circulation 37:518, 1968 12. Crosby IK, Carrel1 R, Reed WA: Operative management of valvular complications of bacterial endocarditis. J Thorac Cardiovasc Surg 64:235, 1972 17, 20, 27, 29, 30, 39, 42, 44, 45,47,481. Preven13. Danielson GK, Titus JL, DuShane JW: Successful tion of contamination of t h e valve prosthesis is treatment of aortic valve endocarditis and aortic dependent on excision of the infected tissue, root abscesses by insertion of prosthetic valve in closure of annular abscesses, and antimicrobial ascending aorta and placement of bypass grafts therapy [8, 19, 341. As in our 2 patients, t h e to coronary arteries. J Thorac Cardiovasc Surg annulus m a y be grossly necrotic b u t cultures of 67:443, 1974 t h e annulus may be negative [21. Intensive 14. Dismukes WE, Karchmer AW, Buckley MJ, et al: Prosthetic valve endocarditis: analysis of 38 antibiotic therapy and thorough debridement cases. Circulation 48:365, 1973 of the diseased tissue should limit the occur- 15. Friedberg CK: Subacute bacterial endocarditis: ence of septic graft complications. revision of diagnostic criteria and therapy. JAMA 144:527, 1950 16. Gonzalez-Lavin L, Scappatura E, Lise M, et al: References Mycotic aneurysms of the aortic root: a complication of aortic valve endocarditis. Ann Thorac 1. Amoury RA, Bowman FO, Malm JR: Endocarditis associated with intracardiac prostheses: Surg 9:551, 1970 diagnosis, management and prophylaxis. J 17. Hairston P, Lee WH Jr: Management of infected Thorac Cardiovasc Surg 51:36, 1966 prosthetic heart valves. Ann Thorac Surg 9:229, 2. Arnett EN, Roberts WC: Prosthetic valve en1970 docarditis: clinicopathologic analysis of 22 nec- 18. Hatcher CR, Symbas PN, Logan WD, et al: Surgiropsy patients with comparison of observations cal aspects of endocarditis of the aortic root. Am J in 74 necropsy patients with active infective enCardiol 23: 192, 1969 docarditis involving natural left-sided cardiac 19. Hatcher CR, Symbas PN, Logan WD, et al: Surgivalves. Am J Cardiol38:281, 1976 cal management of complications of bacterial en3. Bentall H, DeBono A: A technique for complete docarditis. Ann Surg 173:1045, 1971 replacement of the ascending aorta. Thorax 20. Hurley EJ, Eldridge FL, Hultgren HN: Emergency replacement df valves in endocar23:338, 1968 ditis. Am Heart J 73:798, 1967 4. Boyd AD, Spencer FC, Isom OW, et al: Infective endocarditis: an analysis of 54 surgically treated 21. Kay JH, Bemstein S, Feinstein D, et al: Surgical cure of Candida albicans endocarditis with open patients. J Thorac Cardiovasc Surg 73:23, 1977 heart surgery. N Engl J Med 264:907, 1961 5. Braniff BA, Shumway NE, Hamson DC: Valve replacement in active bacterial endocarditis. N 22. Kloster FE: Diagnosis and management of complications of prosthetic heart valves. Am J CarEngl J Med 276:1464, 1967 diol35:872, 1975 6. Bristow JD, Parker BM, Haug WA: Hemopericardium following rupture of a bacterial 23. Koizumi S, Mohri H, Kagawa Y, et al: Surgical treatment of annuloaortic ectasia: experience in 7 aortic sinus aneurysm. Am J Cardiol 6:355, 1960 7. Brown JW, Salles CA, Kirsh MM: Extraanatomconsecutive patients. Ann Thorac Surg 25:425, 1978 ical bypass of the aortic root: an experimental 24. Kouchoukos NT, Karp RB, Lell WA: Replacement technique. Ann Thorac Surg 24:433, 1977 of the ascending aorta and aortic valve with a 8. Buckley MJ, Mundth ED, Daggett WM, et al: composite graft: results in 25 patients. Ann Surgical management of the complications of Thorac Surg 24:140, 1977 sepsis involving the aortic valve, aortic root, and 25. Lichtman SS: Treatment of subacute bacterial ascending aorta. Ann Thorac Surg 12:391, 1971 endocarditis: current results. Ann Intem Med 9. Carnes WH, Tinsley CM: The pathological re19:787, 1943 sults in cases of bacterial endocarditis treated 26. Littlefield JB, Muller WH, Dammann JF: Sucwith penicillin. Stanford Med Bull 4:78, 1946 cessful treatment of Pseudomonas aeruginosa sep10. Cates JE, Christie RV: Subacute bacterial enticemia following total aortic valve replacement. docarditis: a review of 442 patients treated in 14 Circulation 31:Suppl 1:1-103, 1965 centers appointed by the Penicillin Trials Committee of the Medical Research Council. Q J Med 27. Manhas DR, Mohri H, Hessel EA, et al: Experience with surgical management of primary in20:93, 1951

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