Surgical treatment of prosthetic endocarditis

Role of echocardiogram in decision making for surgery in endocarditis

Infective endocarditis is a serious disease that carries significant morbidity and mortality. Adequate treatment is based on a high degree of clinical suspicion, accurate microbiologic diagnosis, and high-quality imaging. Echocardiography has been shown to be a fundamental tool for diagnosis and management. Currently accepted Duke criteria include blood cultures and echocardiography. Transthoracic and transesophageal echocardiography play a critical role in the decision-making process, especially when surgical treatment is contemplated. Because infective endocarditis is considered a medical and surgical disease, and considering that the current rate of surgery is about 50%, echocardiography has definite value in preoperative diagnosis and surgical planning, intraoperative confirmation of lesions and quality of repair or replacement before and after cardiopulmonary bypass, and postoperative assessment.

Surgical Treatment of Paraannular Aortic Abscess

BACKGROUND

Aortic valve endocarditis with paraannular abscess remains a challenging problem in the surgical treatment of native and prosthetic valve endocarditis. The purpose of this study is to evaluate the long-term outcome of surgical intervention for aortic paraannular abscess.

METHODS

From January 1989 to November 2004, 32 consecutive patients (24 men, 8 women) were studied. Mean age was 50.6 +/- 16.2 (range, 17-80) years. Twenty-four had native valve endocarditis and 8 had prosthetic valve endocarditis. Eight of 24 patients who suffered from native valve endocarditis had bicuspid valve endocarditis. The predominant microorganism was Streptococcus viridans. No microorganisms were identified in 11 patients. Most patients were desperately ill at the time of surgery. Repair was performed by aggressive eradication of infected tissue and reconstruction of the defect with autologous pericardium (n = 24), bovine pericardium (n = 3), Dacron patch (n = 4), and primary closure (n = 1).

RESULTS

Although postoperative complications were common, early mortality occurred in only 4 patients (12.5%). Operative survivors have been followed for 5 months to 16 years (mean, 92.7 months). There were 2 late deaths but all were noncardiac deaths. Five patients (15.6%) underwent reoperation at a mean of 55.4 months after the initial surgery. The actuarial survival at 1, 5, and 10 years was 87.4% +/- 5.9%, 83.2% +/- 6.9%, and 79.1% +/- 7.7%, respectively. The freedom from reoperation at 1, 5, and 10 years was 88.7% +/- 6.2%, 79.8% +/- 8.1% and 75.4% +/- 8.8%, respectively.

CONCLUSION

These data suggest that aggressive surgical intervention and meticulous antibiotic therapy for aortic valve endocarditis with paraannular abscess yields a high success rate with relatively low mortality and good long-term results.

Pseudoaneurysm from the mitral-aortic intervalvular fibrosa following endocarditis

A rare case of a pseudoaneurysm from the mitral-aortic intervalvular fibrosa following bacterial endocarditis in a 17-year-old male is presented. Destructive infection secondarily involved the mitral-aortic intervalvular fibrosa. Perforation of this portion resulted in the formation of the pseudoaneurysm situated at the base of the left ventricle between the aorta and the left atrium. With echocardiography, computed topography, angiography, and magnetic resonance imaging (MRI), a pseudoaneurysm was diagnosed. MRI especially revealed detailed information and the extension of pseudoaneurysm. Our patient underwent resection of the pseudoaneurysm, reconstruction of left ventricular outflow with glutaraldehyde-preserved bovine pericardium, and replacement of the aortic valve. His postoperative course was uneventful. No recurrence of endocarditis was detected in the following year.

Acute endocarditis treated with radical debridement and implantation of mechanical or stented bioprosthetic devices

BACKGROUND

Operation for active infective endocarditis carries high mortality and morbidity rates, especially when the annulus is involved. Overall the literature favors the use of autograft and homograft valves because of better resistance to infection. In our clinic during the last 5 years we used an aggressive surgical approach to infective endocarditis in combination with implantation of mechanical or stented bioprosthetic devices.

METHODS

From 1994 to 1999, 50 adults with aortic and/or mitral valve endocarditis underwent valve replacement. The median age of the 36 men and 14 women was 58 years (range, 17 to 78 years). All patients had active endocarditis at the time of operation. Native valve endocarditis was present in 48 patients and prosthetic valve endocarditis was present in 2 patients. The aortic valve was affected in 24 patients, the mitral valve in 21 patients, and both the aortic and mitral valves in 5 patients. Two of the patients with mitral endocarditis also had infection of the tricuspid valve. Annular destruction was present in 24 patients (48%). The patients were treated with radical excision of all infected tissue. The annular defects were closed, if possible, with direct sutures. Otherwise, a reconstruction was performed. Follow-up was 100% complete with a median follow-up period of 45 months (range, 6 to 66 months).

RESULTS

The procedures were performed without lethal bleeding complications. Early mortality was 12% and the actuarial survival at follow-up was 80%. In none of the patients who died was death related to the prosthetic valve or recurrence of the endocarditis. Only 1 patient (2%) developed recurrence of the infective endocarditis and was reoperated with a Ross procedure. Three and a half years later the patient developed severe valve insufficiency of the autograft and was operated again with implantation of a mechanical device.

CONCLUSIONS

Native and prosthetic valve endocarditis can be treated successfully with aggressive surgical debridement and implantation of mechanical or stented bioprosthetic devices with a low risk of recurrent endocarditis.

Reoperations on the ascending aorta and aortic root: pitfalls and results in 134 patients

BACKGROUND

This analysis was performed to evaluate the results of reoperations on the ascending aorta and aortic root.

METHODS

All reoperations (n = 134) on the aortic root and ascending aorta performed between February 1981 and April 1998 were retrospectively analyzed. Indications for reintervention were a true or false aneurysm (35%), acute dissection (3.0%), aortic valve stenosis and/or insufficiency (23.1%), prosthetic valve endocarditis (32.8%), and combinations (4.5%). The principal reoperations performed were aortic root replacement (composite graft, freestyle, aortic allograft, or pulmonary autograft) in 116 patients, ascending aortic replacement in 10 patients, and closure of a false aneurysm in 5 patients. Results were analyzed using univariate statistical methods.

RESULTS

Hospital mortality was 6.6% (8 patients). Univariate predictors of hospital death were preoperative functional class III or IV (p = 0.02), an interval of less than 6 months between the primary and actual operation (p = 0.02), preoperative creatinine level of more than 200 micromol/L (p = 0.001), acute aortic dissection (p = 0.001), intraoperative technical problems (p = 0.001), and postoperative dialysis (p = 0.001). Freedom from repetitive reoperation was 99% at 1 year and 98% at 5 and 10 years.

CONCLUSIONS

Reoperations on the aortic root and ascending aorta can be performed with an early mortality which is very acceptable.

Allograft aortic root replacement in prosthetic aortic valve endocarditis: a review of 32 patients

BACKGROUND

This study was conducted to evaluate allograft aortic root replacement in the setting of complicated prosthetic valve endocarditis with extensive annular destruction.

METHODS

From January 1990 through March 1996, 32 patients diagnosed with complicated prosthetic valve endocarditis underwent allograft root replacement. Mean age was 58.3 +/- 13.2 years; 23 patients were men. Mean preoperative New York Heart Association functional class was 3.4. Staphylococcus epidermidis (50%) and Enterococcus faecalis (19%) were the predominant causative microorganisms. Annular abscesses were found in 26 patients (81%), aortic-mitral discontinuity in 14 patients (43%), and left ventricular-aortic discontinuity in 11 patients (34%). A cryopreserved allograft was used in 31 patients (97%) and a fresh antibiotic-treated allograft was used in 1 patient (3%). Mean aortic cross-clamp time was 150 +/- 29 minutes. Mean duration of the postoperative antibiotic treatment was 38.5 +/- 11.8 days.

RESULTS

There were three operative deaths (9.4%); causes of death were multiorgan failure in 2 patients (6.2%) and low cardiac output in 1 patient (3.2%). Six patients (18%) had complete heart block (4 patients already before the operation), 3 patients (9.4%) had temporary respiratory insufficiency, and 1 patient (3.2%) needed temporary hemodialysis. Mean follow-up was 37.4 +/- 22.4 months. Two late deaths occurred: 1 patient had recurrent endocarditis, leading to a false aneurysm, and died at reoperation; another patient died of lung cancer. Actuarial 5-year survival was 87.3% (70% confidence interval, 76.8% to 97.8%); actuarial 5-year freedom from recurrent endocarditis was 96.5% (70% confidence interval, 90.0% to 100%).

CONCLUSIONS

Allograft aortic root replacement is a valuable technique in the complex setting of prosthetic valve endocarditis with involvement of the periannular region. Mortality and morbidity are low.

Homograft Aortic Root Replacement for Early Prosthetic Endocarditis

Early prosthetic aortic valve endocarditis was managed by aortic root replacement using fresh antibiotic sterilized pulmonary or aortic homografts. A report of 3 consecutive cases with a brief review of literature is presented.

Surgical technique of implanting the stentless porcine mitral valve

The new stentless porcine mitral valve was developed to serve as an anatomically correct substitute for a diseased mitral valve. Extensive acute animal experimentation was performed, and from this the logical sequence for selecting the correct valve size and the specific technique for implanting it were determined. The following are the major steps to successfully implant a mitral stentless valve: First, mitral valve complex analysis must be done to determine the correct procedure to be performed and the feasibility of using the stentless mitral valve. Second, the correct size of stentless mitral valve must be chosen. Third, the papillary muscle anatomy must be assessed to determine the site and number of sutures necessary for securely holding the new origin of the new chordae. Fourth, the papillary muscle sutures must be anchored to the free pericardial edge of the new chordal origin. Fifth, the chordal alignment with both trigonal areas must be perfect. Sixth, the annulus may be sutured using either continuous or interrupted sutures. Perioperative echocardiography, preferably transesophageal echocardiography, should be done in every patient. Although reoperation was necessary in 5 patients (non-valve-related), the results in 74 patients (3 early and 3 late non-valve-related deaths excluded) followed up for at most 26 months (mean, 14 months) have been excellent. The quality of the results obtained in this initial clinical trial has reinforced our current preference for this valve in patients requiring mitral valve replacement. Longer follow-up is required to confirm that these good results continue.

Allograft aortic root replacement: standardization and simplification of technique

A variety of surgical techniques for implantation of an allograft aortic valve have been described. Compounding this confusion, the host pathologic processes necessitating aortic valve or root replacement are many, often associated with asymmetry of the aortic root and valve annulus. These complexities can now be negated by routinely performing allograft aortic root replacement with pedicle coronary artery reimplantation in all situations. This procedure is described in a simple step-by-step manner that makes it amenable to all cardiac surgeons independent of experience.

Ascending Aorta to Femoral Bypass with Cryopreserved Vascular Homografts

Homograft vascular replacement is almost as old as vascular surgery itself. Gross and Dubost are credited as the first authors who clinically attempted vascular reconstruction using biological tissue of human origin. The advent of synthetic vascular prostheses together with the complexity of logistics in procuring, preserving, and storing vascular homografts made the routine use of vascular homografts impractical. Cryopreservation techniques have strongly influenced the use of biological tissue. The tireless work of a few authors has enabled us to better understand the behavior of homograft tissues in cardiovascular surgery. Homograft replacement of the aortic and pulmonary valves is now a recognized way to treat a number of conditions of the aortic root and the right ventricular outflow tract. Renewed interest in the use of cryopreserved homografts in cardiac surgery has led us to expand our own indications for their use. As our Cryopreservation Unit is fully operative, we also have vascular homografts available for implantation. Here we describe the extended use of vascular homografts in extraanatomic aortic bifurcation bypass in a patient with previous multiple vascular operations. To use the ascending aorta as the inflow source in cardiovascular reconstruction has been previously described; however, it has not been popular among surgeons. Robicsek termed this type of bypass graft “very long” aortic grafts, and we recently had the chance to use fully biological tissue of human origin for this type of reconstruction.

Infective endocarditis in patients who had replacement of the aortic root

In 12 patients who had had composite replacement of the aortic valve and ascending aorta, infective endocarditis developed 2 months to 17 years after operation. Six patients had mechanical valves and 6 had biological ones (four homograft and two porcine valves). All patients needed operation because of shock, heart failure, persistent sepsis in spite of adequate antibiotic therapy, or the development of a paravalvular false aneurysm. The predominant microorganism was Staphylococcus. All 6 patients who had mechanical valves were found to have an abscess in the junction between the aortic annulus and the prosthesis; in patients who had biological valves the infection was limited to the leaflets in 3 (one homograft and two porcine valves) and leaflets and annulus abscess in 3 (three homograft valves). Operation consisted of radical resection of tissues suspected of being infected and reconstruction of the left ventricular outflow tract and of the surrounding structures with glutaraldehyde-fixed bovine pericardium. The aortic valve and ascending aorta were replaced with a new valved conduit. An aortic homograft was used in only 1 patient. There was only one operative death due to right ventricular infarction but most patients experienced serious postoperative complications. Operative survivors were followed up from 3 to 156 months (mean, 42 months). One patient died 35 months postoperatively due to bleeding complications of anticoagulation; 1 patient suffered a cardiac arrest at home 2 months after operation, sustained permanent cerebral damage, and died 4 months later. The remaining patients are asymptomatic from the cardiovascular viewpoint.(ABSTRACT TRUNCATED AT 250 WORDS)

Annular abscesses and GRF glue

Infective endocarditis of the aortic prosthesis is a serious complication of valve surgery. The correction of this condition is difficult and complex procedures are often required. Two patients with aortic bioprosthetic endocarditis complicated with annular abscesses were operated on. The aortic valve was replaced with a bioprosthesis and the annular abscesses were debrided and closed with the aid of gelatin-resorcin-formalin (GRF) glue, which completely sealed the abscess cavities. One year later the patients were asymptomatic and had no clinical or echocardiographic signs of aortic incompetence.

Fibrous skeleton endocarditis: repair using Konno procedure

Information about the surgical management of fibrous skeleton endocarditis is incomplete, as the vast majority of current literature describes the isolated repair of either the aortic or the mitral annulus, the combination rarely being addressed. Annular destruction, in the presence of endocarditis, demands extreme ingenuity for surgical treatment and cure. We describe and illustrate the Konno procedure for replacement of both infected mitral and aortic valves and repair of mycotic ventricular septal defects.

Composite graft replacement of the aortic valve and ascending aorta with Cabrol technique

Replacement of the aortic valve, root and ascending aorta with the technique first described by Cabrol was performed on 17 patients. In five cases the aortic arch was also replaced. The indications were type A aortic dissection with aortic insufficiency (8 cases, with acute dissection in 7), native endocarditis with severe aortic insufficiency and aortic root abscess (3 cases), prosthetic endocarditis (3), and true aneurysm of the ascending aorta with aortic insufficiency (3). Acute surgery was performed in 15 cases (88%). The overall operative mortality was 41%. For the patients discharged from hospital the mean observation time was 30 months. None died, but in one case the right leg of the interposition graft became occluded and reoperation was required 40 months after the primary operation for acute type A dissection. The described technique of aortic valve and root displacement can be used in all cases in which use of a composite graft is indicated, except in situations where the coronary ostia and arteries are damaged by acute dissection.

The efficacy of controlled antibiotic release for prevention of polyethyleneterephthalate- (Dacron-) related infection in cardiovascular surgery

Infection of prostheses containing polyethyleneterephthalate (Dacron) remains a dreaded complication in cardiovascular surgery despite perioperative antibiotic (AB) prophylaxis. Dacron, which is widely applied as a fabric for manufacturing vascular prostheses and also the sewing rings of artificial heart valves, remains a source for infection once implanted in the body. In order to increase the AB concentration in Dacron, an experimental study including topical application of the gentamicin derivative EMD 46/217 and fibrin sealant (F) as AB carrier was initiated. In-vitro pretreatment of Dacron with the gentamicin derivative and F was followed by constant AB release for three weeks. In a subsequent animal study, four Dacron rings with different pretreatments were implanted in the descending aorta of ten pigs after direct contamination with 10 8 Staph. aureus solution. One ring was pretreated with the AB/F compound, a second ring with the AB alone. Ring 3 (no pretreatment) and ring 4 (F alone) served as controls. After one week, the Dacron rings and their corresponding implantation sites were asserved for measurement of AB content and for culture. The AB content of AB/F rings was 24.99 +/- 7.16 mug/g wet weight, while Dacron rings pretreated with the AB alone contained no measurable drug amounts, with the exception of one specimen (0.5 mug/g)(AB/F versus AB rings: P less than 0.0005).(ABSTRACT TRUNCATED AT 250 WORDS)

Periaortic hematoma formation leading to aortic valve failure. A complication of homograft placement for second valve surgery

The aortic homograft has become the replacement valve of choice in the treatment of complicated endocarditis involving native and prosthetic aortic valves. Complications are rare, typically involving chronic leaflet degeneration causing valvular insufficiency or rarely chronic calcific stenosis. We present a case in which functional stenosis of the homograft valve was caused by compression and distortion by blood transmitted directly from the left ventricle into a space between the homograft and an external cavity formed by a Dacron wrap. The latter had been placed to help control suture-line bleeding. This case presentation demonstrates an unusual cause of homograft failure and suggests that wrapping of a homograft conduit by native aorta or an external Dacron wrap is not a substitute for meticulous surgical technique to assure a hemostatic suture line.

Pulmonary autograft. An aortic valve replacement alternative

In selected patients, the pulmonary autograft procedure utilizing cryopreserved homografts for reconstruction of the right ventricular outflow tract is becoming an increasingly popular aortic valve replacement alternative. Longitudinal statistical reports show that patients need reoperation less often with this procedure. Because the valve is autogenous tissue, all indications to date show that the valve continues to function for extended periods of time in all patients and can accommodate growth in children. At the same time, transfer of the pulmonary valve to the aortic position provides a natural valvular flow pattern and freedom from the degenerative changes associated with bioprosthetic valves or the need for anticoagulation associated with mechanical valves.

Comparison of allografts and prosthetic valves when used for emergency aortic valve replacement for active infective endocarditis

Aortic valve replacement (AVR) using allografts is an established method of treating aortic valve disease. It is uncertain, however, whether the increased technical demands of allograft AVR can be justified in emergency operations. This study reports 15 patients treated between 1987 and 1990 for acute bacterial or fungal endocarditis involving the aortic valve. Patients underwent emergency AVR because of severe congestive failure, overwhelming sepsis or cerebral emboli. Eight patients received prosthetic valves (group I: 4 mechanical, 4 porcine) and 7 received human allografts (group II: 5 aortic and 2 pulmonary). The groups were comparable in age (group I, 55 years; group II, 51 years), intravenous drug abuse (group I, 1; group II, 3), and previous AVR (group I, 3; group II, 2). One group I and 4 group II patients had septal abscesses. Additional procedures in group I included mitral valve replacement (2), tricuspid valve replacement (1) and aortic root replacement (1). Additional procedures in group II were mitral valve repair (1), root replacement (1), atrial septal defect closure (1) and aortocoronary bypass (1). Mean bypass times (group I, 189 minutes; group II, 204 minutes) and cross-clamp times (group I; 108 minutes; group II, 121 minutes) were similar. Operative deaths occurred in 4 of 8 group I and 1 of 7 group II patients. All surviving patients have been successfully followed (group I, 28 months; group II, 18 months). No group I patient has required reoperation. One group II patients required reoperation for recurrent infection affecting the allograft, and another group II patient died 10 months postoperatively from noncardiac causes.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of complicated prosthetic aortic valve endocarditis with annular abscess formation by homograft aortic root replacement

The outcome of 30 consecutive patients with active aortic prosthetic valve endocarditis and root abscesses treated by the technique of homograft aortic root replacement with reimplantation of the coronary arteries is detailed. The principles of this technique are the removal of all abscesses and infected areas likely to drain into the infected mediastinum, excision of infected tissues down to healthy noninfected tissue and replacement with an antibiotic-impregnated homograft aortic root. All patients had evidence of progressive cardiac failure and ongoing sepsis. Mean patient age (+/- SD) at the time of operation was 42 +/- 18 years. The mean number of previous aortic valve replacements per patient was 1.6 +/- 0.7; 14 patients (47%) had undergone greater than or equal to 2 previous replacements. At operation, aortic root abscesses were found in all patients; abscess extension to adjacent structures and partial valve dehiscence had occurred in 23. In-hospital death occurred in 9 (30%) of the 30 patients. The 21 hospital survivors have been followed up for a mean of 66 +/- 42 months (range 9 to 144). Overall, 17 (81%) of the 21 hospital survivors have remained free of major adverse events (recurrence of endocarditis, need for reoperation or death). The results of our study suggest that homograft aortic root replacement should be considered favorably in the treatment of patients with aortic prosthetic valve endocarditis and root abscesses.

Results of homograft aortic valve replacement for active endocarditis

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 (3), and Candida (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 valve/root replacement is an effective method for management of active endocarditis complicated by annular destruction.

Use of pericardium to control bleeding after ascending aortic graft replacement

We present the case of a patient who required replacement of an ascending aortic composite graft for endocarditis complicated by uncontrollable bleeding from the proximal anastomotic site. A new method of creating a right atrial-to-periprosthetic space fistula with autologous pericardium was used with a favorable result.

Allograft aortic valve implantation: techniques for all types of aortic valve and root pathology

The geometry and degree of symmetry of the diseased aortic root and valve dictate the technical method of implantation of the allograft aortic valve. Five methods are available that are suitable for the full range of aortic root disease: the small aortic root with a valve annulus diameter less than 21 mm, the common aortic valve lesions (valve annulus diameter, 21 to 29 mm), the aneurysmal noncoronary sinus, the moderately large annulus (valve annulus diameter greater than 30 mm), and the aneurysmal aortic root and dilated annulus. Implantation methods include the subcoronary technique, miniroot inclusion technique, and aortic root replacement. Technical variations such as valve inversion during implantation, valve rotation, and continuous or interrupted suture methods are important in certain techniques. The allograft aortic valve is a versatile device that can be used in the surgical management of the full range of aortic valve and aortic root pathology.

Viable cryopreserved aortic homograft for aortic valve endocarditis and annular abscesses

Six consecutive patients with active aortic valve endocarditis, including 2 with extensive subannular aortic root abscess, were successfully treated with viable cryopreserved homograft aortic valve replacement. Two patients required extensive aortic root reconstruction with an appropriately trimmed aortic homograft to cover large abscess cavities. All patients showed resolution of infection with no perioperative mortality or clinically significant morbidity. Three patients had a minor degree of aortic insufficiency on postoperative echo-Doppler study. On follow-up at 6 to 48 months, all patients were in New York Heart Association functional class I. The resistance of the unstented homograft to infection makes it an attractive choice for patients requiring aortic valve replacement for active endocarditis. The results of surgical intervention in patients with extensive aortic root involvement may be further improved by the flexibility afforded by the homograft to be "custom-fit" to the abnormal aortic root and the ability to achieve secure abnormal aortic root and the ability to achieve secure valve fixation without use of prosthetic material.

Homograft aortic root replacement to correct infective endocarditis requiring seven open cardiac procedures

Infective endocarditis, presumably from a septic dental focus, affecting the aortic valve was seen as acute aortic regurgitation in a 20-year-old woman. Seven open cardiac procedures for replacement of the aortic valve and left ventricular outflow tract were performed over the subsequent 6 years. Aortic root replacement using a fresh antibiotic-sterilized homograft was performed as the last definitive operative procedure. This article is presented to highlight (1) the use of homograft aortic root replacement for extensive involvement of aortic valve and left ventricular outflow tract in cases of infective endocarditis and (2) the feasibility of multiple sternal reentries when indicated.

[Bacterial endocarditis on prosthetic valves]

Bacterial endocarditis is a rare, but often lethal, complication of cardiac valve replacement. The endocarditis is called "early" when it occurs within 2 months of the operation, and "late" when it develops after that period. Contamination of the prosthesis with bacteria may occur intra-operatively or post-operatively. The clinical diagnosis is often difficult in early endocarditis when another focus of infection is present and in late endocarditis in the absence of fever and positive blood cultures. Isolation of the pathogen from blood cultures is essential to the diagnosis and treatment. Therapeutic surgery now has wider indications than formerly. The incidence of this dangerous complication can only be reduced by well-planned and well executed prophylactic measures.

Fifty cases of late prosthetic valve endocarditis: improvement in prognosis over a 15 year period

The clinical course, prognostic factors, and management of 50 cases of late prosthetic valve endocarditis, occurring more than two months after valve replacement, were reviewed. Twenty nine cases that presented from 1971 to 1980 were compared with 21 cases that presented from 1981 to 1985. Apart from an appreciable decrease in the frequency of neurological complications between the first period (38%) and the second period (10%) no differences in clinical or bacteriological features were seen. Seventeen (59%) of the 29 cases in the earlier period and four (19%) of the 21 cases in the later period died. The rationale for antimicrobial treatment was similar during both periods. Cardiac surgery was performed in eight of 29 cases between 1971 and 1980 and in 11 of 21 between 1981 and 1985; the mean (SD) time between diagnosis of endocarditis and operation was 28 (19) days and 43 (44) days respectively. Six of the eight cases operated on in the first period died as did two of the 11 operated on in the second period. Twenty seven of the 29 cases presenting between 1971 and 1980 were treated with anticoagulants--either warfarin (15 of 27) or heparin sodium (12 of 27). Sixteen of the 21 cases presenting later were given anticoagulants and 15 of these cases were given heparin sodium. Control of anticoagulation was inadequate in nine of the 27 cases treated with anticoagulants during the first period and in only two of 16 treated during the second period. During the first treatment period neurological complications were more frequent when control of anticoagulation was inadequate.

A practical approach to prosthetic valve endocarditis

Prosthetic valve endocarditis (PVE) is an infrequent but dread complication, occurring in 1 to 2% of patients both early (less than 60 days) and late postoperatively. Diagnosis is always (99%) possible by two sets of blood cultures, but occasional exogenous causes of bacteremia may cloud the diagnosis, as will culture-negative cases of PVE and skin contaminants. With obvious exogenous sources of bacteremia, achieving sterile blood cultures after eradication of the noncardiac source permits discontinuation of antibiotics after two weeks. When skin contaminants are suspected, withholding antibiotics and obtaining two sets of blood cultures is recommended, because the bacteremia with PVE is continuous. Preventive measures, including perioperative antibiotics, are warranted but will probably not significantly reduce the low incidence of infection already achieved. The major cause of improved survival in recent years is earlier operation (valve rereplacement). This has been demonstrated in the last ten years and is absolutely indicated for major heart failure, ongoing sepsis, fungous etiology, valve obstruction, new-onset heart block, and unstable prosthesis by fluoroscopy.

Patch closure of aortic annulus mycotic aneurysms

Twenty-three patients with bacterial endocarditis and mycotic aneurysms of the aortic annulus were treated between 1978 and 1985. There were 18 men and 5 women ranging from 24 to 72 years old. All patients had congestive heart failure and positive blood cultures as a complication of the endocarditis and were in New York Heart Association (NYHA) Functional Class III or IV. The aneurysm complicated late prosthetic valve endocarditis in 7 patients and native valve endocarditis in 16. The most common infecting organisms were streptococci (12 patients) and staphylococci (7 patients). The noncoronary sinus was the most frequent site for aneurysm formation. Following debridement of the abscess cavity, the orifice of the aneurysm was closed with a patch of Dacron in 20 patients and autologous pericardium in 3. A prosthetic valve (18 bioprosthetic and 5 mechanical) was secured to the noninfected portion of the native annulus and to the patch at the level of annulus. There were 3 deaths, 1 perioperative and 2 late, each without evidence of residual infection or aortic insufficiency. There are 20 late survivors (87%). After a mean follow-up of 1 year, all patients are in NYHA Functional Class I. Patch closure of mycotic aneurysms involving the aortic annulus permits aggressive debridement of the abscess cavity and affords closure of the orifice without tension. The prosthetic valve can be seated at the level of the native annulus, thus avoiding complicated reconstructive procedures of the aortic root and coronary arteries. This technique is an effective alternative in selected cases of mycotic aneurysms involving the aortic annulus.