Surgical treatment of active infective endocarditis with paravalvular involvement

Aortic Valve Infective Endocarditis Complicated by Annular Abscess: Antibiotics in the Abscess Cavity

OBJECTIVES

Infective endocarditis of the aortic valve complicated by annular abscess is a challenging problem and often requires patch reconstruction after surgical debridement of the abscess cavity. Filling the remaining cavity with antibiotics is advocated to prevent recurrent endocarditis. This study aimed at evaluating the role of local antibiotics in patients with aortic valve infective endocarditis complicated by annular abscess.

METHODS

Between January 2012 and December 2021, all consecutive patients with aortic valve infective endocarditis complicated by annular abscess undergoing cardiac surgery and annular patch reconstruction were included. Patients receiving local antibiotics were compared with patients without local antibiotics. The primary endpoints were the incidence of recurrent endocarditis, re-operation, and mortality during two-year follow-up.

RESULTS

A total of 41 patients with aortic valve infective endocarditis complicated by annular abscess underwent surgical patch reconstruction after radical debridement. In total, 20 patients received local antibiotics in the abscess cavity and 21 patients were treated without local antibiotics. The most common causative microorganisms were the staphylococci species and the most common location of the abscess was the non-coronary annulus. During two-year follow-up, one patient in each group developed recurrent endocarditis (p > 0.99) and both patients were reoperated (p > 0.99). Two-year mortality was 30% in the local antibiotic group and 24% in the control group (p = 0.65).

CONCLUSIONS

Radical debridement and patch reconstruction of the aortic annulus in patients with aortic valve infective endocarditis complicated by annular abscess is an effective surgical strategy. Filling of the remaining abscess cavity with antibiotic seems not to affect the rate of recurrent endocarditis, reoperation, and mortality during two-year follow-up.

Contemporary surgical management of infective endocarditis of the aortic root

Infective endocarditis involving the aortic root is associated with a high degree of morbidity and mortality. Native aortic root infections can develop from aggressive organisms or from delays in diagnosis or definitive care, whereas prosthetic valve infections commonly result in extensive destruction of the aortic root and neighboring structures. Early detection, tailored antibiotic therapy, thoughtful pre-operative planning, and multidisciplinary heart team management are the keys to optimizing patient outcomes. Aggressive and complete surgical debridement are mandatory prior to aortic root reconstruction. Surgical experience and patient-centered decision making are critical in selecting the optimal reconstructive strategy for the aortic root and adjacent structures.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12055-023-01604-6.

The Effect of Local Administration of Vancomycin Suspended in Fibrin Glue for Prevention of Surgical Site Infection After Spinal Instrumentation: Comparison by Probability of Treatment Weighting Model

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

To compare the surgical site infection (SSI) rate in patients undergoing spinal instrumentation surgery who received vancomycin suspended in fibrin glue at the surgical site and those who did not.

SUMMARY OF BACKGROUND DATA

The intrawound application of vancomycin powder for preventing SSI after spinal surgery remains controversial. Vancomycin suspended in fibrin glue is another option for local administration that may be effective. The present study assessed whether vancomycin suspended in fibrin glue could prevent SSI after spinal instrumentation surgery.

MATERIALS AND METHODS

We enrolled patients who underwent posterior spinal instrumentation surgery with or without fusion for degenerative conditions, spinal trauma, or tumor. A multiple logistic regression model with inverse probability of treatment weighting based on propensity score was used to assess the efficacy of vancomycin suspended in fibrin glue and to account for confounding. A secondary multivariate logistic regression analysis was performed to identify the risk factors associated with SSI.

RESULTS

Of the 264 patients enrolled in this study, 134 underwent application of vancomycin suspended in fibrin glue at the surgical site and 130 did not. The incidence of SSI was lower in patients who were treated with vancomycin suspended in fibrin glue (2.2% vs. 8.5%) even after inverse probability of treatment weighting adjustment (adjusted odds ratio: 0.25; 95% CI, 0.0768-0.91; P =0.03). Multivariate logistic regression analysis showed that the treatment with vancomycin suspended in fibrin glue was significantly associated with a lower odds of SSI (odds ratio: 0.2; 95% CI, 0.05-0.85; P =0.03).

CONCLUSIONS

The administration of vancomycin suspended in fibrin glue was significantly associated with a lower likelihood of SSI in patients undergoing spinal instrumentation surgery.

In vitro and Ex vivo Assessments of the Compatibility of Fibrin Sealant with Antimicrobial Compounds

Background: Fibrin sealants are used as antimicrobial-releasing carriers for preventing surgical site infections; however, it is important to determine the release kinetics and antimicrobial effects of drugs added to fibrin sealants and the effects of drugs on clot/clotting properties. Materials and Methods: The antimicrobial and antibiofilm activity of cefazolin, colistin, gentamicin, oxacillin, tobramycin, and silver nitrate released from fibrin sealant were characterized using in vitro and ex vivo assays against bacteria commonly found on the skin. The effects of antimicrobial agents on the physical structure of the fibrin sealant were assessed with scanning electron microscopy (SEM) and on the clotting rate and strength of fibrin clots using run-off tests and rheology. Results: Generally, antibiotic agents were released gradually from fibrin sealant and were stable after release, with antimicrobial effects evident up to three days. Cefazolin, gentamicin, and oxacillin prevented biofilm formation of Staphylococcus aureus in porcine skin explants; gentamicin and colistin prevented biofilm formation of Pseudomonas aeruginosa. Gentamicin, cefazolin, colistin, and tobramycin did not affect the structural integrity or viscoelastic properties of fibrin sealant; changes were observed with oxacillin (SEM) and particularly silver nitrate (SEM and rheology). No antimicrobial agents caused deterioration of clotting time (run-off tests). Conclusions: From the antimicrobial agents tested, gentamicin and cefazolin showed prolonged release from fibrin sealant, sustained antimicrobial activity, and biofilm prevention properties against Staphylococcus aureus; similar results were observed for gentamicin and colistin against Pseudomonas aeruginosa. For each of these findings, the physical structure of the fibrin sealant, clotting rate, and strength of fibrin clots were unaffected.

Surgical treatment and long-term outcome of aortic valve endocarditis with periannular abscess

Objectives

Aortic valve endocarditis is occasionally complicated by periannular spreading of the infection and abscess formation, leading to a more aggressive course of the disease and life-threatening complications. This retrospective observational study investigated the long-term outcomes of patients with this complication, which was surgically managed with annular reconstruction and aortic valve replacement.

Methods

Between 1998 and 2018, 69 patients were identified with aortic valve endocarditis complicated by periannular abscess formation. All patients were treated with debridement of the infected tissue, gentamicin filling of abscess cavities, annulus reconstruction with bovine pericardium, and valve replacement. Long-term follow-up was performed to detect the rate of recurrence of endocarditis, aortic valve reoperation and survival.

Results

Mean age was 58 ± 15 years, 81% of patients were male, and the infected valve was native in 51% of all patients. The overall mortality was 36%, with a 30-day mortality of 13% and 120–day mortality of 16%. Five- and 10-year survival was 69.4 ± 12.0% and 55.7 ± 14.3%, respectively. Ten-year freedom from recurrent endocarditis was 83.5 ± 13.3%.

Conclusion

Endocarditis with annular abscess remains associated with high morbidity and mortality and aggressive treatment of the infected tissue and abscess cavities is crucial. Compared with earlier literature, long-term outcome of annular reconstruction in this series is comparable to that of aortic root replacement.

Reoperative Aortic Root Replacement in Patients with Previous Aortic Root or Aortic Valve Procedures

Background

Generalization of standardized surgical techniques to treat aortic valve (AV) and aortic root diseases has benefited large numbers of patients. As a consequence of the proliferation of patients receiving aortic root surgeries, surgeons are more frequently challenged by reoperative aortic root procedures. The aim of this study was to evaluate the outcomes of redo-aortic root replacement (ARR).

Methods

We retrospectively reviewed 66 patients (36 male; mean age, 44.5±9.5 years) who underwent redo-ARR following AV or aortic root procedures between April 1995 and June 2015.

Results

Emergency surgeries comprised 43.9% (n=29). Indications for the redo-ARR were aneurysm (n=12), pseudoaneurysm (n=1), or dissection (n=6) of the residual native aortic sinus in 19 patients (28.8%), native AV dysfunction in 8 patients (12.1%), structural dysfunction of an implanted bioprosthetic AV in 19 patients (28.8%), and infection of previously replaced AV or proximal aortic grafts in 30 patients (45.5%). There were 3 early deaths (4.5%). During follow-up (median, 54.65 months; quartile 1–3, 17.93 to 95.71 months), there were 14 late deaths (21.2%), and 9 valve-related complications including reoperation of the aortic root in 1 patient, infective endocarditis in 3 patients, and hemorrhagic events in 5 patients. Overall survival and event-free survival rates at 5 years were 81.5%±5.1% and 76.4%±5.4%, respectively.

Conclusion

Despite technical challenges and a high rate of emergency conditions in patients requiring redo-ARR, early and late outcomes were acceptable in these patients.

Fibrin matrices: The versatile therapeutic delivery systems

Fibrin sealants, that have been employed for over a century by surgeons to stop post surgery bleeding, are finding novel applications in the controlled delivery of antibiotics and several other therapeutics. Fibrinogen can be easily purified from blood plasma and converted by thrombolysis to fibrin that undergoes spontaneous aggregation to form insoluble clot. During the gelling, fibrin can be formulated into films, clots, threads, microbeads, nanoconstructs and nanoparticles. Whole plasma clots in the form of beads and microparticles can also be prepared by activating endogenous thrombin, for possible drug delivery. Fibrin formulations offer remarkable scope for controlling the porosity as well as in vivo degradability and hence the release of the associated therapeutics. Binding/covalent-linking of therapeutics to the fibrin matrix, crosslinking of the matrix with bifunctional reagents and coentrapment of protease inhibitors have been successful in regulating both in vitro and in vivo release of the therapeutics. The release rates can also be remarkably lowered by preentrapment of therapeutics in insoluble particles like liposomes or by anchoring them to the matrix via molecules that bind them as well as fibrin.

Reconstructing the infected aortic root with antibiotic impregnated biological glue

Prosthetic valve dehiscence and persistent infection are two complications following reconstruction of the aortic root in destructive endocarditis. A technique is described involving the principles of aggressive debridement, closure of large abscess cavities with biological material incorporating a slurry of antibiotic-impregnated biological sealant, and replacement of the aortic valve with an aortic allograft valve. This strategy appears to have been successful in preventing persistent endocarditis and valve dehiscence in a limited number of patients.

Prevention of early vascular graft infection using regional antibiotic release

BACKGROUND

Infections after prosthetic replacement of the aorta remain a serious and life-threatening complication. The only appropriate treatment is the surgical removal of the infected prosthesis. Accordingly, there is a need for new procedures to prevent the infection of vascular prostheses. This in vitro experiment investigated the effect of the pretreatment of vascular prostheses with antibiotics (daptomycin or baneocin) and the effect of antibiotics combined with fibrin sealant as possible prophylaxis of perioperative graft infection.

METHODS

Untreated prostheses served as controls. Pretreated prostheses of double woven velour vascular grafts were contaminated with Staphylococcus epidermidis, and colony-forming units were counted each day (CFU/mL).

RESULTS

The period of sterility differed significantly as a function of the pretreatment. Uncoated prostheses were immediately non-sterile and exhibited 2.63 ± 0.61 × 10(5) CFU/mL. Baneocin pretreatment resulted in sterility for 1.7 ± 0.6 (95% confidence interval (CI) 1.0-2.4) d before we detected 2.14 ± 0.57 × 10(5) CFU/mL on the prostheses. Pretreatment with daptomycin yielded 2.9 ± 0.4 (CI 2.6-3.2) and fibrin sealant/baneocin compound yielded 3.1 ± 0.3 (CI 2.9-3.3) d of sterility, after which 1.81 ± 0.86 × 10(5) CFU/mL and 1.04 ± 0.77 × 10(5) CFU/mL were recorded. Finally, pretreatment with fibrin sealant/daptomycin led to sterility for 7.1 ± 0.3 (CI 6.9-7.3) d, after which 0.77 ± 0.60 × 10(5) CFU/mL were observed on the prostheses.

CONCLUSIONS

The risk of vascular graft infection is reduced by pretreating the prostheses with antibiotics. The antibiotic/fibrin compound exhibited an effect of delayed antibiotic release. Vascular prostheses should therefore be pretreated with antibiotic solution to reduce bacterial adhesion. This procedure might be an effective prophylaxis for perioperative vascular graft infection and provides suitable protection for the prosthetic material.

Commissural autologous pericardial patch repair: a novel technique for active mitral valve endocarditis involving the mitral annulus

In patients with massive destruction caused by mitral endocarditis, surgical valve repair remains a challenging issue. Although several procedures have previously been introduced, no standard method for complicated lesions has been established. We describe a technique of mitral valve repair for extensive destructive endocarditis involving both leaflets and the mitral annulus that has provided satisfactory initial results in 2 patients. This procedure is believed to be technically simple and beneficial in terms of mitral repair for active endocarditis.

Endocarditis with massive aortic root abscess and atrioventricular septal destruction

Endocarditis involving the aortic root and intervalvular fibrous skeleton presents a reconstructive dilemma. We report a case of endocarditis involving the aortic root and tricuspid valve with extensive destruction of the atrioventricular septum. Debridement necessitated resection of the aortic root, aortic valve, tricuspid valve, and a large portion of atrioventricular septum, leaving the right atrium, right ventricle, left ventricle and aorta in open communication. Reconstruction was accomplished by separating the left and right hearts with a Dacron patch, tricuspid valve replacement, and aortic root replacement. Proper planar localization of the aortic root was necessary to avoid left ventricular outflow obstruction and coronary torsion.

An alternative patch repair technique during valve replacement for native valve endocarditis

A patient with native valve endocarditis and vegetation on anterior mitral leaflet underwent aortic valve replacement with preservation of aortic noncoronary leaflet as a patch over the inflamed intervalvular fibrous body. This technique may minimize prosthetic material use, which is the most important risk factor for reinfection.

Evaluation and management of aortic valve and root disease

Aortic valve disease manifests in the form of stenosis, regurgitation, or some combination, yielding either excessive afterload and/or excessive preload on the left ventricle. Aortic root disease may affect valvular function, causing regurgitation; may simply be coexistent with stenotic aortic valvular disease; or may exist despite normal aortic valve function. Indications for intervening on aortic valve or root disease are determined by the presence of symptoms, by the pathology's impact on left ventricular function, or by the inherent risk of aortic catastrophe (dissection, disruption, or sudden death). Aortic valvular and root diseases are primarily treated by surgical replacement of the pathologic structures. Mechanical aortic valve replacement has long-term durability but requires continuous anticoagulation. Bioprostheses do not require anticoagulation but have more limited durability. Valve-sparing aortic root replacement and aortic valve repair offer the potential for indefinite durability without the need for anticoagulation but are technically more difficult to perform and require more stringent selection criteria based on determining the reparability of an aortic valve. Emerging percutaneous valve technologies offer new hope for patients who are not candidates for aortic valve surgery, but the applicability and durability of percutaneous aortic valves are not yet known. Timely and appropriate intervention in aortic valve and root disease can result in the restoration of a normal life span for patients with aortic valvular and/or root disease.

Surgical treatment of paravalvular abscess: long-term results

OBJECTIVE

To examine the outcomes of surgery for active infective endocarditis with paravalvular abscess.

METHODS

Paravalvular abscess was defined as infective necrosis of the valve annulus that required patch reconstruction before implanting a new valve. Of 383 patients with active infective endocarditis who underwent surgical treatment, 135 (35%) had paravalvular abscess. Patients' mean age was 51+/-16 years and 68% were men. The infected valve was native in 69 patients and prosthetic in 66. The abscess involved the aortic annulus in 73 patients, the mitral annulus in 27, the aortic and mitral annuluses in 33, and the aortic and tricuspid and/or pulmonary annuluses in 2. Surgery consisted of radical resection of the abscess, reconstruction of the annulus with patches and valve replacement. Mean follow-up was 6.2+/-5.2 years and complete.

RESULTS

There were 21 (15.5%) operative deaths. Preoperative shock and abscess in the aortic and mitral annuluses were independent predictors of operative death. There were 34 (25%) late deaths. Survival at 15 years was 43+/-6% for all patients, 50+/-8% for native valve endocarditis and 35+/-9% for prosthetic (p=0.41). Age by increments of 5 years and recurrent endocarditis were independent predictors of late death. There were 16 episodes of recurrent endocarditis in 15 patients, and the freedom from recurrent endocarditis was 82+/-4% at 15 years. Fifteen reoperations were performed in 14 patients. Freedom from reoperation was 72+/-9% at 15 years.

CONCLUSIONS

Surgery for active endocarditis with paravalvular abscess was associated with high operative mortality, particularly in patients in shock and abscess of both mitral and aortic annuluses. Long-term survival was adversely affected by age and recurrent bouts of endocarditis.

Periannular complications in infective endocarditis involving native aortic valves

The extension of infection in native valve infective endocarditis (IE) from valvular structures to the periannular tissue is incompletely understood. It is unknown, for example, whether the prognosis of patients with aortocavitary fistulae is worse than that of those with nonruptured abscesses. The aims of this study were to determine the distinct clinical characteristics of patients with aortocavitary fistulae and nonruptured abscesses in native valve IE and to evaluate the impact of fistulization on the outcomes of patients with native aortic valve IE complicated with periannular lesions. In a retrospective multicenter study of 2,055 native valve IE episodes, 201 patients (9.8%) with periannular complications in aortic valve IE were identified (46 with aortocavitary fistulization and 155 with nonruptured abscesses). Rates of heart failure (p = 0.07), ventricular septal defect (p <0.001), and third-degree atrioventricular block (p = 0.07) were higher in patients with fistulization. Surgical treatment was undertaken in 172 patients (86%), and in-hospital mortality in the overall population was 29%. Multivariate analysis identified age >60 years (odds ratio [OR] 2.6, 95% confidence interval [CI] 1.3 to 5.2), renal failure (OR 3.0, 95% CI 1.5 to 6.0), and moderate or severe heart failure (OR 2.5, 95% CI 1.2 to 5.2) as independent risk factors for death. There was a trend toward increased in-hospital mortality in patients with aortocavitary fistulae (OR 1.5, 95% CI 0.7 to 3.0). The actuarial 5-year survival rate in surgical survivors was 80% in patients with fistulae and 92% in patients with nonruptured abscesses (log-rank p = 0.6). In conclusion, aortocavitary fistulous tract formation in the setting of native valve IE is associated with higher rates of heart failure, ventricular septal defect, and atrioventricular block than nonruptured abscess. Despite these higher rates of complications, fistulous tract formation in the current era of IE is not an independent risk factor for mortality.

Importance of surgical timing on postoperative outcome in patients with native valve acute endocarditis

BACKGROUND

The present study was undertaken to establish whether surgical outcome could be influenced by surgical timing in patients affected by native valve endocarditis (NVE).

METHODS

From March 2002 to December 2004, 19 patients underwent surgical operation for NVE. Aortic valve replacement (AVR) was performed in ten patients (53%), mitral valve repair (MVRep) was performed in five patients (26%) and multivalvular procedures were performed in the remaining four patients (21%). In three patients (15.5%), emergency surgery was required for refractory congestive heart failure, urgent surgery was necessary in ten patients [in six patients (31%) for paravalvular abscess, in three patients (15.5%) for macrovegetations and in one patient (6%) for systemic embolism, respectively], five patients (26.3%) with isolated valve incompetence underwent elective surgery, whereas delayed surgery was reserved for one patient (6%) because of pre-operative embolic stroke.

RESULTS

There were no surgical procedure, cardiac or infectious related deaths at 30 days in the entire group. One patient died from an intravenous overdose. Follow-up was 100% complete in the 18 hospital survivors and ranged from 4 to 37 months (mean 14.2 +/- 10 months). There were no late death, recurrence of endocarditis, or re-operation at follow-up.

CONCLUSIONS

The surgical results for NVE are excellent if surgical timing criteria are correctly applied during the acute phase of the infectious process. Immediate surgical correction is required when rapid hemodynamic deterioration occurs whereas a more aggressive surgical approach appears to be advisable in the case of paravalvular abscess, macrovegetations or systemic embolism. Delayed surgery is recommended when pre-operative stroke develops.

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.

Risk factor analysis of hospital mortality in patients with endocarditis with ring abscess

BACKGROUND

Endocarditis associated with ring abscess is a pathology with high morbidity and mortality.

AIM OF THE STUDY

The purpose of this study was to analyze hospital mortality risk factors in patients with ring abscess due to endocarditis.

METHODS

From January 1982 to December 2000, 104 patients underwent surgical intervention at the Heart Institute of the University of São Paulo Medical School for valve endocarditis with ring abscess. The age ranged from 6 years to 73 years, with an average of 40.3 years and 72.1% were male. According to NYHA functional class (FC), 12 (11.5%) were in FC II, 62 (59.6%) in FC III, and 30 (28.9%) in FC IV. Seventy-seven (74.0%) patients had endocarditis on a bioprosthesis, 58 (55.8%) in the aortic position and 19 (18.3%) in the mitral position. Twenty-nine (26.9%) patients had atrioventricular blockage prior to the operation. Univariate analysis was performed comparing variables and hospital mortality with a level of significance of 5%. Multivariate analysis was performed by logistic regression.

RESULTS

The hospital mortality was 19.2% (20 patients). Univariate analysis showed that atrioventricular blockage, age, and prosthetic valve endocarditis significantly influenced hospital mortality. Multivariate analysis identified atrioventricular blockage as an independent predictor of hospital mortality.

CONCLUSIONS

Preoperative atrioventricular blockage is an independent risk factor for hospital mortality in the surgical treatment of endocarditis with ring abscess.

Bacteriological Outcome after Valve Surgery for Active Infective Endocarditis: Implications for Duration of Treatment after Surgery

BACKGROUND

There has been no systematic evaluation of outcome after surgery for infective endocarditis with respect to duration of antibiotic treatment.

METHODS

We performed a retrospective chart review of episodes of valve surgery for active infective endocarditis at Green Lane Hospital (Auckland, New Zealand) for 1963-1999. We recorded the duration of antibiotic treatment before and after valve surgery; the extent of infection at operation; Gram stain, culture, and histopathological testing results for valve samples; and the bacteriological outcome after surgery. The primary outcome measure was relapse, defined as endocarditis due to the same species within 1 year after surgery.

RESULTS

For the 358 patients in our study, the median duration of follow-up was 4.8 years. Thirty-two patients (9%) had 36 subsequent episodes of endocarditis. Relapse occurred after 3 (0.8%) of the operations (95% CI, 0.2%-2.0%). Relapse of infection was unrelated to the duration of antibiotic treatment before or after surgery, positive valve culture results, positive Gram stain results, or perivalvular infection. Since 1994, we have reduced the duration of antibiotic treatment by approximately 7 days for those with positive valve culture results and by approximately 14 days for those with negative valve culture results, without any increase in the number of relapses.

CONCLUSIONS

Relapse is an uncommon event following surgery for endocarditis. Commonly suggested indications for prolonging postoperative treatment are not associated with higher relapse rates, and their relevance is debatable. We conclude that it is unnecessary to continue treatment for patients with negative valve culture results for an arbitrary 4-6-week period after surgery. Two weeks of treatment appears to be sufficient, and, for those operated on near the end of the standard period of treatment, simply completing the planned course should suffice.

Aorto-cavitary fistulous tract formation in infective endocarditis: clinical and echocardiographic features of 76 cases and risk factors for mortality

AIMS

To investigate the clinical features, echocardiographic characteristics, management, and prognostic factors of mortality of aorto-cavitary fistulization (ACF) in infective endocarditis (IE). Extension of infection in aortic valve IE beyond valvular structures may result in peri-annular complications with resulting necrosis and rupture, and subsequent development of ACF. Aorto-cavitary communications create intra-cardiac shunts, which may result in further clinical deterioration and haemodynamic instability.

METHODS AND RESULTS

In a retrospective multi-centre study over 4681 episodes of IE, a total of 76 patients with ACF [1.6%, confidence interval (CI) 95%: 1.2-2.0%] diagnosed by echocardiography or during surgery were identified. Fistulae were found in 1.8% of cases of native valve IE and in 3.5% of cases of prosthetic valve IE from the general population and in 0.4% of drug abusers. PVE was present in 31 (41%) cases of ACF. Transthoracic and transoesophageal echocardiography detected the fistulous tracts in 53 and 97% of cases, respectively. Peri-annular abscesses were detected in 78% of cases, fistulae originated in similar rates from the three sinuses of Valsalva, and the four cardiac chambers were equally involved in the fistulous tracts. Heart failure (HF) developed in 62% of cases and surgery was performed in 66 (87% CI 95% 77-93%) patients with a mortality of 41% (95% CI 30-53%) in the overall population. Multivariate analysis identified HF (OR 3.4, CI 95% 1.0-11.5), prosthetic IE (OR 4.6, CI 95% 1.4-15.4) and urgent or emergency surgical treatment (OR 4.3, CI 95% 1.3-16.6) as variables significantly associated with an increased risk of death. Major complications during follow-up (death, re-operation, or re-admission for HF) among the five operative survivors with residual fistulae occurred in 20 and 100% of patients at 1 and 2 years, respectively.

CONCLUSION

Aorto-cavitary fistulous tract formation is an uncommon but extremely serious complication of IE. In-hospital mortality was exceptionally high despite aggressive management with surgical intervention in the majority of patients. Prosthetic IE, urgent surgery, and the development of HF identify the subgroup of patients with IE and ACF that have significantly increased risk of in-hospital death.

Replacement of the aortic root for acute prosthetic valve endocarditis: Prosthetic composite versus aortic allograft root replacement

OBJECTIVE

Aortic root replacement for prosthetic aortic valve endocarditis with accompanying destruction of the aortic root is a well-established surgical intervention. However, there is still no consensus whether prosthetic material or allogeneic material should be used. Here we report on our experience with prosthetic composite and aortic allograft root replacement in such patients during a 10-year interval.

METHODS

From 1991 through 2001, 29 patients with prosthetic aortic valve endocarditis combined with aortic root destruction underwent reoperation at our institution. Sixteen patients received aortic root replacement with a cryopreserved aortic root allograft (group A) and 13 with a prosthetic composite graft (group B). The interval between the initial operation and reoperation was 29 months (range, 5-168 months) in group A and 55 months (range, 7-248 months) in group B.

RESULTS

Hospital mortality was 18.5% (n = 5 patients, 3 in group A and 2 in group B). Median follow-up was 21 months (range, 1-48 months) for group A and 34 months (range, 1-152 months) for group B (P >.2). Survival at 1 and 5 years was 81% +/- 10% and 81% +/- 10% in group A and 85% +/- 10% and 85% +/- 10% in group B, respectively. No patient underwent reoperation for recurrent prosthetic aortic valve endocarditis.

CONCLUSIONS

Our results indicate that excellent long-term results can be achieved regardless of the material used for aortic root replacement in patients with prosthetic aortic valve endocarditis.

A freeze-dried fibrin disc as a biodegradable drug release matrix

A fibrin clot loaded with soluble tetracycline (TET) was prepared and lyophilized to make discs of a size and shape to use as a drug delivery matrix. On subcutaneous implantation of these discs in mice, they were found to have degraded in 15 days as evidenced by gross and histological examination. The in vitro discharge kinetics of tetracycline from the disc into phosphate buffered saline (PBS) and human serum were compared. It was observed that the release rate of tetracycline from the matrix into serum remained steady from day 1 to day 12, maintaining sufficient concentration that may be required to control microbial growth in the medium. Two different concentrations of fibrinogen were used to fabricate discs denoted as FG200 and FG100, and in both cases the retention rate was comparable when the study medium was serum. In contrast, when suspended in PBS instead of serum, the delivery of the drug into the medium was found to be high for up to the 3rd day when a sharp decline in discharge was observed. The fibrinogen used is a factor that determines not only the longevity of discharge but also fibrinolysis. The degradation of the disc in vitro was visible when the discs were suspended in the buffer, and correspondingly fibrin degradation product (FDP) measured in the medium using an antibody-based assay system was high. Fibrin disc is haemostatic and biodegradable in vivo, and in vitro release of a small molecule at a controlled rate is demonstrated here. Hence, it may be a suitable candidate as a drug delivery implant for short-term use.

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.

Current best practices and guidelines. Assessment and management of complications in infective endocarditis

The most important complications of endocarditis are congestive heart failure, paravalvular abscess formation, and embolism, especially stroke. In addition, endocarditis may be complicated by septic arthritis, vertebral osteomyelitis, pericarditis, metastatic abscesses and an array of renal problems ranging from immune-complex glomerulonephritis to renal abscesses. Adverse reactions associated with medical treatment of endocarditis can also result in significant complications such as ototoxicity and nephrotoxicity, skin rashes, and serum sickness. This review focuses on the cardiac, embolic, neurologic and renal complications of endocarditis and discusses how these complications influence the clinical management of individual cases in daily practice.

Replacing the ascending aorta and aortic valve for acute prosthetic valve endocarditis: is using prosthetic material contraindicated?

BACKGROUND

The use of prosthetic material (rather than a homograft) for ascending aorta/aortic valve replacement (Bentall procedure) in cases of acute prosthetic valve endocarditis is controversial. We report favorable results using this technique almost exclusively (a homograft was used in only 3 patients with hematological problems) during a 12-year interval.

METHODS

Twenty-eight patients (55 +/- 14 years; 22 male) underwent a Bentall procedure for acute prosthetic valve endocarditis between 1988 and 2000. Twenty-five patients had undergone previous aortic valve replacement (1 with concomitant mitral valve replacement, 4 with coronary artery bypass grafting), and 3 had had a previous Bentall operation. The median interval between initial surgery and reoperation was 13 months (range, 1 to 106). Sixty-eight percent of operations were urgent or emergencies. Ninety-three percent of patients had significant aortic regurgitation; complete annuloaortic dehiscence occurred in 71%, and in 57%, an abscess was found. Causative organisms were identified in 25 of 28 patients: Staphylococcus epidermidis (9), Staphylococcus aureus (7), Streptococcus viridans (6), Pseudomonas (2), and Legionella (1).

RESULTS

Twenty-three patients had mechanical and 5 had biological valves implanted during the Bentall procedure. Hypothermic circulatory arrest was used in 64%. Hospital mortality was 11%: there was one intraoperative death, and two before discharge (one cardiac, one sepsis). Eighty-nine percent survived without stroke. During follow-up (median, 44.5 months; complete in 92%), 1 patient died of recurrent endocarditis at 4 months.

CONCLUSIONS

These results indicate that prosthetic root replacement may be superior to use of a homograft for acute aortic prosthetic valve endocarditis, with only a 4% incidence of recurrent endocarditis and reoperation.

Optimal Size of Prostheses for Functioning of the Aortic Prosthetic Valve in Aortic and Mitral Valve Replacement with Annular Enlargement through Manouguian's Technique

There is not yet agreement about the optimal size of the prostheses in aortic and mitral valve replacement with Manouguian's technique. In this technique, the aortic prosthetic valve can be pushed upon the mitral prosthesis which may cause dysfunction of the aortic prosthetic valve. The aim of this study was to clarify the size of the prostheses needed to avoid dysfunction of the aortic prosthetic valve. Three patients underwent aortic and mitral valve replacement through this procedure. Two of them had active aortic and mitral valve endocarditis. Aortomitral continuity involved with abscesses could be approached and completely excised using this technique. All patients survived the operation, but 1 of them suffered aortic mechanical valve dysfunction for the reason stated. Anatomical analysis of the geometrical relation of the 2 prosthetic valves suggests that the mitral annulus should be enlarged less than 25 mm to avoid dysfunction of the aortic prosthetic valve.

Current best practices and guidelines. Assessment and management of complications in infective endocarditis

The most important complications of endocarditis are congestive heart failure, paravalvular abscess formation, and embolism, especially stroke. In addition, endocarditis may be complicated by septic arthritis, vertebral osteomyelitis, pericarditis, metastatic abscesses and an array of renal problems ranging from immune-complex glomerulonephritis to renal abscesses. Adverse reactions associated with medical treatment of endocarditis can also result in significant complications such as ototoxicity and nephrotoxicity, skin rashes, and serum sickness. This review focuses on the cardiac, embolic, neurologic and renal complications of endocarditis and discusses how these complications influence the clinical management of individual cases in daily practice.

Treatment and prevention of infective endocarditis

The paper presents the most recent recommendations for the treatment and prevention of infective endocarditis (IE). The treatment of IE is complex and requires close collaboration among specialists in infectious diseases, cardiology, cardiac surgery and microbiology. The mainstay of medical treatment is antibiotic therapy. Theoretical considerations regarding vegetations and antibiotics have practical consequences on the route and modalities of administration of antibiotics and on the techniques used to monitor treatment. The choice of antibiotics depends on the microorganism (streptococci, enterococci, staphylococci, HACEK group [Haemophilus sp., Actinobacillus sp., Cardiobacterium sp., Eikenella sp. and Kingella sp.], Coxiella, Brucella, Legionella, Bartonella, fungi) and on whether IE occurs on native or prosthetic valves. Treatment of IE with negative blood cultures is particularly difficult. Cardiac surgery is often needed during the bacteriologically active period (in ~50% of patients). The decision to intervene and the optimal timing of the intervention requires careful consideration of multiple potential risks: the haemodynamic risk, the infectious risk, the risk due to cardiac lesions, the risk due to extracardiac complications and the risk due to the location of infective endocarditis. Even though the efficacy of antibiotic prophylaxis of IE is not completely proven, it is recommended for selected patients who undergo an at-risk procedure. Lists of cardiac conditions and of medical procedures at risk are presented; specific antibiotic prophylactic regimens for dental and upper respiratory tract procedures in out-patients, procedures under general anaesthesia and urological and GI procedures are outlined.

Ross operation for active culture-positive aortic valve endocarditis with extensive paravalvular involvement

BACKGROUND

We evaluated the midterm results of the Ross operation in active advanced endocarditis.

METHODS

Between June 1994 and June 2000 a pulmonary autograft aortic root replacement was performed in 11 consecutive patients who had urgent or emergent procedures for active endocarditis with extensive involvement of the aortic root (10 native, 1 prosthetic). Patients ranged in age from 26 to 45 years (median, 33 years). Indications for operation were uncontrolled infection (n = 5), hemodynamic deterioration (n = 3), or both (n = 3). Four patients were in the New York Heart Association class III, 6 in class IV, and 1 was operated on while in cardiogenic shock. Four patients (36%) suffered an embolic cerebrovascular accident preoperatively. The endocarditis affected the mitral valve in 2 patients and the tricuspid valve in 1 patient.

RESULTS

There was no early or late death. Recurrent endocarditis was not detected in any of the patients during the follow-up period ranging up to 72 months (median, 40 months).

CONCLUSIONS

The autograft may well be the best substitute for aortic root reconstruction in advanced endocarditis.

Pneumococcal aortic valve endocarditis causing aortopulmonary artery fistula

We report a case of an aortic-pulmonary artery fistula secondary to acute bacterial endocarditis and aortic root abscess formation. The patient presented with generalized symptoms and an initial pneumococcal pneumonia, then developed respiratory and cardiac failure necessitating ventilation and inotropic agents. An echocardiogram showed a vegetation in the aortic valve, an abscess involving the aortic root, and suggested a fistula between the aorta and main pulmonary artery, which was confirmed at emergent operation. Despite a complicated early postoperative course the patient has made a full recovery.

Long term results of mechanical prostheses for treatment of active infective endocarditis

OBJECTIVE

To analyse the long term results of mechanical prostheses for treating active infective endocarditis.

DESIGN

Prospective cohort study of a consecutive series of patients diagnosed with infective endocarditis and operated on in the active phase of the infection for insertion of a mechanical prosthesis.

SETTING

Tertiary referral centre in a metropolitan area.

RESULTS

Between 1975 and 1997, 637 cases of infective endocarditis were diagnosed in the centre. Of these, 436 were left sided (with overall mortality of 20.3%). Surgical treatment in the active phase of the infection was needed in 141 patients (72% native, 28% prosthetic infective endocarditis). Mechanical prostheses were used in 131 patients. Operative mortality was 30.5% (40 patients). Ninety one survivors were followed up prospectively for (mean (SD)) 5.4 (4.5) years. Thirteen patients developed prosthetic valve dysfunction. Nine patients suffered reinfection: four of these (4%) were early and five were late. The median time from surgery for late reinfection was 1.4 years. During follow up, 12 patients died. Excluding operative mortality, actuarial survival was 86.6% at five years and 83.7% at 10 years; actuarial survival free from death, reoperation, and reinfection was 73.1% at five years and 59.8% at 10 years.

CONCLUSIONS

In patients surviving acute infective endocarditis and receiving mechanical prostheses, the rate of early reinfection compares well with reported results of homografts. In addition, prosthesis dysfunction rate is low and long term survival is good. These data should prove useful for comparison with long term studies, when available, using other types of valve surgery in active infective endocarditis.

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.

Nosocomial endocarditis in the intensive care unit: an analysis of 22 cases

OBJECTIVES

To review the intensive care unit experience of patients with admitted or acquired nosocomial endocarditis (NE) defined according to the Duke criteria.

DESIGN

Prospective, cohort study.

SETTING

University teaching hospital.

PATIENTS

We reviewed the records of 22 patients documented with NE during a 6-yr period from 1992 to 1997.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Twenty-two patients (9 women/13 men) aged 38-83 yrs (mean 65+/-9 yrs) had a NE (prevalence of 5 per 1,000 admissions). For six patients, NE was the reason for the admission to the intensive care unit. For 17 patients, the time elapsed between admission and diagnosis of NE was 39+/-25 days. Sixteen patients were predisposed to infection and seven had underlying heart conditions that put them at risk for acute endocarditis: three prosthetic valves, two valvular diseases, and two cardiac pacemakers. In 21 cases (one unknown portal of entry), NE was the consequence of bacteremia related to a medical or surgical procedure: 11 intravascular devices, eight surgical wounds, one tracheal procedure, and one leg ulceration. The bacteriologic agents detected in blood cultures were: staphylococci (n = 17), Streptococcus (n = 2), Pseudomonas aeruginosa (n = 2), and Candida (n = 2). Fourteen patients underwent echocardiography according to cardiac signs (cardiac failure, new cardiac murmur, or embolic event). For the eight remainders, echocardiography was performed systematically because of fever and positive blood cultures. The lesions detected by 21 transthoracic and 17 transesophageal echocardiographs were the following: vegetations (n = 19), myocardial abscesses (n = 5), and valvular perforation (n = 1). On 16 surgical indications, only five patients underwent surgery because the others were in too poor of a condition. The overall mortality was 68% (n = 15) and was directly associated with NE in 36% of cases (n = 8). Seven patients (28%) were discharged 34 days after the diagnosis of endocarditis.

CONCLUSIONS

NE is a frequent nosocomial infection that occurs late during hospitalization. Persistent fever with positive blood cultures is sufficient symptomology to promptly perform an echocardiogram. The poor prognosis is related to the poor condition of those patients who cannot be referred for surgical treatment.

Studies in thoracic aortic graft infections: the development of a porcine model and a comparison of collagen-impregnated dacron grafts and cryopreserved allografts

OBJECTIVE

A porcine model of thoracic aortic graft infection was created, and various anatomic sites and the timing of inoculation of the graft to induce infection were investigated. Ultimately, the ability of cryopreserved allograft to resist infection was compared with that of collagen-impregnated Dacron graft.

METHODS

Yorkshire pigs (n = 16) underwent placement of an expanded polytetrafluoroethylene patch graft in the ascending aorta and the left atrial appendage (phase I). Eight animals were immediately given a 50-mL bolus (1 x 10(8) cfu/mL) of Staphylococcus aureus whereas the other 8 received the infusion 24 hours later. Animals were put to death 8 weeks later and the grafts were sterilely explanted and analyzed via microbiologic culture and standard histologic procedures for evidence of infection. The results displayed that the aortic graft and a delay of induced bacteremia of 24 hours were more reliable methods of producing infection. During phase II, 13 pigs were randomized to receive either a collagen-impregnated Dacron graft (n = 6) or a cryopreserved allograft (n = 7) in the ascending aortic position only and infusion of S aureus 24 hours after the operation. The experiment then proceeded to completion.

RESULTS

Phase I results displayed that use of an aortic graft and induced bacteremia 24 hours after the operation was a more reliable and reproducible method of producing infection. In phase II, graft infection was present in 38.5% (5/13) of animals, with only 16.7% (1/6) in the collagen-impregnated Dacron graft group and 57.2% (4/7) in the cryopreserved allograft group becoming infected. There was no significant difference between the collagen-impregnated Dacron graft and cryopreserved allograft groups in the incidences of thoracic aortic graft infections (P =.27, Fisher exact test).

CONCLUSIONS

This novel porcine model of thoracic aortic graft infection is a reproducible method for the investigation of thoracic aortic graft infections. The phase I study investigated the timing of the induced bacteremia and the most susceptible position of a graft. Phase II demonstrated that collagen-impregnated Dacron grafts are equivalent, if not superior, to cryopreserved allografts in resisting central vascular graft infections in the ascending aorta.

New developments in the treatment of infective endocarditis infective cardiovasculitis

The natural history of infective endocarditis has undergone remarkable changes over the past 100 years as regards both the demographic characteristics of the disease and changes in the incidence of the so-called diagnostic signs. Alongside these changes and the development of new and better diagnostic tools and criteria, we are also facing new problems with the precise definition of cardiovascular infections and calculation of the incidence of the disease. Nosocomial endocarditis presents an emerging problem of diagnosis and treatment after heart valve surgery, with pace-maker catheters, defibrillators and a very large variety of foreign materials used in connection with heart valve surgery. New technological progress including new types of prosthetic valves and use of homografts or the Ross operation will give a greater possibility of choosing the best solution in a particular case. Antimicrobial chemotherapy is mainly based on our understanding of the pathophysiology of the disease and efficacy of the antibiotics achieved in an experimental animal model of endocarditis. Important recommendations of single or combined drug therapy or the dosing regimens of antibiotics are still an expression of expert opinion not always supported by experimental or clinical proof. A typical example is the recommendation of two divided doses of gentamicin for treatment of streptococcal endocarditis. Nevertheless, it is the author's opinion that the development of uncomplicated, easy to handle diagnostic and treatment regimens are justified in order to achieve better compliance with these recommendations.

Aorto-Left Atrial Fistula Complicating Native Aortic Valve Endocarditis

A 21-year-old male with native aortic valve Streptococcus viridans endocarditis was found to have an aorto-left atrial fistula by transthoracic echocardiography. He underwent successful fistula plication and aortic valve replacement.