A comparative study of 48 host valve and 24 prosthetic valve endocarditis cases

Infective endocarditis epidemiology over five decades: a systematic review

AIMS

To Assess changes in infective endocarditis (IE) epidemiology over the last 5 decades.

METHODS AND RESULTS

We searched the published literature using PubMed, MEDLINE, and EMBASE from inception until December 2011.

DATA FROM

Einstein Medical Center, Philadelphia, PA were also included. Criteria for inclusion in this systematic review included studies with reported IE microbiology, IE definition, description of population studied, and time frame. Two authors independently extracted data and assessed manuscript quality. One hundred sixty studies (27,083 patients) met inclusion criteria. Among hospital-based studies (n=142; 23,606 patients) staphylococcal IE percentage increased over time, with coagulase-negative staphylococcus (CNS) increasing over each of the last 5 decades (p<0.001) and Staphylococcus aureus (SA) in the last decade (21% to 30%; p<0.05). Streptococcus viridans (SV) and culture negative (CN) IE frequency decreased over time (p<0.001), while enterococcal IE increased in the last decade (p<0.01). Patient age and male predominance increased over time as well. In subgroup analysis, SA frequency increased in North America, but not the rest of the world. This was due, in part, to an increase in intravenous drug abuse IE in North America (p<0.001). Among population-based studies (n=18; 3,477 patients) no significant changes were found.

CONCLUSION

Important changes occurred in IE epidemiology over the last half-century, especially in the last decade. Staphylococcal and enterococcal IE percentage increased while SV and CN IE decreased. Moreover, mean age at diagnosis increased together with male:female ratio. These changes should be considered at the time of decision-making in treatment of and prophylaxis for IE.

LeukoScan for imaging infection in different clinical settings: a retrospective evaluation and extended review of the literature

PURPOSE

The aim of the current study was to determine the overall diagnostic accuracy of Tc-99m-labeled antigranulocyte monoclonal antibody Fab' fragments (LeukoScan) for the routine detection of bone and soft tissue infections in a retrospective evaluation.

PATIENTS AND METHODS

138 patients (63 men, 75 women; mean age, 58.29 +/- 25.38 years) with fever of unknown origin and possible endocarditis (n = 59), infection of arthroplastic joints (n = 20), arthritis (n = 16), peripheral (n = 15) and central bone infections (n = 14), soft tissue infection (n = 6), appendicitis (n = 4), pericarditis (n = 2), or vascular graft infection (n = 2) underwent imaging after injection of 555 to 925 MBq (15 to 25 mCi) Tc-99m-labeled antigranulocyte monoclonal antibody Fab' fragments (LeukoScan).

RESULTS

True-positive results were found in 63 of 81 lesions. The overall sensitivity and specificity were 76% and 84%, respectively. In arthritis, seven of seven foci could be detected, whereas false-negative results were found in infections of the femoral bone in three of nine lesions and in periprosthetic infections of long bones in three of eight lesions. Good results were found in five of six soft-tissue infections, in four of six patients with endocarditis, in three of four atypical cases of appendicitis, in two of two infected vascular grafts, and in one of one patient with pericarditis. Subacute and chronic infections of the spine always showed photopenic areas in eight of eight patients. If photopenic lesions were included as diagnostic criteria, the sensitivity and specificity were 88% and 67%, respectively.

CONCLUSIONS

Tc-99m-labeled antigranulocyte monoclonal antibody Fab' fragments can be used for imaging acute infections of peripheral bones and soft tissues. False-negative results are likely in patients with chronic infections. Sensitivity can be increased while decreasing specificity by including photopenic lesions in the spine as diagnostic criteria for localizing disease.

99mTC-labelled antigranulocyte monoclonal antibody FAB' fragments versus echocardiography in the diagnosis of subacute infective endocarditis

OBJECTIVE

We performed this pilot study to gain first clinical data of immunoscintigraphy with 99mTc-labelled anti-NCA-90 antigranulocyte antibody Fab' fragments (99mTc-Fab' (LeukoScan((R)))) in endocarditis.

PATIENTS AND METHODS

99mTc-Fab' and echocardiography were used in 24 consecutive patients with suspected endocarditis. Nuclear medicine imaging was performed after i.v. injection of 925 MBq 99mTc-Fab' fragments and evaluation was done by region of interest (ROI) technique and visually.

RESULTS

Seven patients were found to have endocarditis on the basis of the revised Duke criteria, which served as gold standard. Initial scintigraphy was true positive in five patients and false positive in one. In the five true positives, T/B ratios in projection to the heart valve plane (with T/B>/=1.3+/-0.072) were highly suspicious for florid endocarditis. TTE and TEE were true positive in two and in six patients, whereas false positives were seen in two and in four patients. Scintigraphy was positive in four of the five patients with the false negative TTE and negative in the three false positive TEE. Vice versa, TEE was positive in the two patients with false negative scintigraphy.

CONCLUSIONS

Immunoscintigraphy with 99mTc-Fab' fragments in combination with TEE improves diagnostic accuracy compared with TTE/TEE in patients with subacute infective endocarditis.

Immunoscintigraphy using technetium-99m-labeled anti-NCA-95 antigranulocyte antibodies as an adjunct to echocardiography in subacute infective endocarditis

OBJECTIVES

This study was performed to assess the clinical value of immunoscintigraphy in subacute infective endocarditis.

BACKGROUND

Radiolabeled granulocytes can reveal inflammatory lesions.

METHODS

Using technetium-99m-labeled anti-NCA-95 anti-granulocyte antibodies, planar scintigraphy and single-photon emission computed tomography of the thorax were performed in 72 consecutive patients with suspected endocarditis. Each patient also underwent transthoracic and, if findings were negative, transesophageal echocardiography.

RESULTS

Thirty-three patients were found to have endocarditis on the basis of clinical criteria (surgical confirmation in 17 patients), and the remaining 39 served as control subjects. Initial scintigraphy was true positive in 26 patients (sensitivity 79%) and false positive in 7 (specificity 82%). Echocardiography was true positive in 29 patients (sensitivity 88%) and false positive in 1 (specificity 97%). Scintigraphy was positive in the four patients with false negative echocardiography, and echocardiography was positive in the seven patients with false negative scintigraphy. Thus, the combination of scintigraphy and echocardiography yielded a sensitivity of 100% and a specificity of 82%. In 10 of the 11 patients with two to three follow-up studies, scintigraphy became negative parallel to clinical improvement, indicating decreasing floridity of the inflammatory process.

CONCLUSIONS

Immunoscintigraphy in patients with subacute infective endocarditis provides valuable diagnostic information in equivocal echocardiographic findings and may be used to monitor antibiotic therapy.

Prosthetic valve endocarditis 1976-1987. Antibiotics, anticoagulation, and stroke

We retrospectively reviewed the clinical characteristics and outcomes of 61 patients with 62 episodes of prosthetic valve endocarditis, paying particular attention to neurologic complications (stroke). Atypical features of the group included a benign outcome of early postoperative infection (18% mortality) and a high stroke morbidity and mortality rate with Staphylococcus epidermidis infections. Eleven patients (18%) suffered an embolic stroke, most less than or equal to 3 days after diagnosis and before the initiation of antimicrobial therapy; the rate of embolic stroke recurrence was low (9%). The risk of embolic stroke was lower with bioprosthetic than with mechanical valves. No protective effect of anticoagulation therapy with warfarin was observed. Six patients (8%) suffered brain hemorrhage due to septic arteritis, brain infarction, or undetermined causes; no specific risk of hemorrhagic stroke was evident with anticoagulation therapy. Antibiotic treatment appears to be more important than anticoagulation to prevent neurologic complications in patients with prosthetic valve endocarditis.

Staphylococcus epidermidis endocarditis and mitral valve prolapse

Staphylococcus epidermidis is an infrequent cause of native valve endocarditis. We describe two cases associated with mitral valve prolapse, and discuss the significance, diagnosis and management of this condition.

[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.

Association of parenteral nutrition catheter sepsis with urinary tract infections

The infection rate (IR) of central venous catheters (CVCs) used for parenteral nutrition (PN) was prospectively evaluated over a 12-month period, with emphasis on the relationship between CVC sepsis and preexisting sites of infection. Sepsis was presumed if the CVC tip or blood culture was positive, or if defervescence followed CVC removal. Four hundred seventy-three CVCs were placed for PN for a total of 5,422 patient days, with a mean length of stay of 11.5 days. Twenty two CVCs led to sepsis for an IR of 4.65% or 4.06 infections per 1000 patient days. Twenty of the 22 septic CVCs were in patients with other sites of infection. The IR was 12.0% (20/166) when other sites of infection were present and 0.65% (2/307) in the absence of a second site. The mean length of stay was 13.2 days for CVCs with other sites of infection and 10.3 days for CVCs with no other site of infection. Fifty nine percent of septic CVCs had secondary sites of infection that included urinary tract infections (UTI). Of all septic CVCs, 22.7% had no site of infection other than UTI. The presence of UTI appears to present a high risk of CVC sepsis. Appropriate identification and treatment of UTI prior to CVC insertion is recommended.

Changing pattern of infective endocarditis

There has been a significant trend toward an increase in the age of patients with endocarditis, and it seems likely that the age of these patients will continue to increase as the population ages. The proportion of patients with endocarditis who have rheumatic heart disease as an underlying lesion has decreased from about 40 percent in patients studied from 1950 to 1970 to about 25 percent in more recent series, and this trend will probably continue. Prosthetic valves and degenerative heart disease will undoubtedly become increasingly important underlying heart lesions in patients with endocarditis. Another large group of patients with infective endocarditis have no diagnosable underlying heart disease and comprise an increasing proportion of patients with endocarditis. Because of the aging of the population, more Streptococcus bovis and enterococcal endocarditis should be expected. With more prosthetic valves and with the aging of the population, more staphylococcal endocarditis should be anticipated. Economic forces will probably result in earlier discharge from the hospital, with either shorter courses of therapy or completion of therapy at home and perhaps more valve replacements.

Factors affecting survival in prosthetic valve endocarditis. Review of the effectiveness of prophylaxis

We review factors affecting survival of 44 episodes of prosthetic valve endocarditis occurring in 39 patients from 1965 to 1982. The mortality was 31.8 percent (14/44), and 21.6 percent (8/37) if the fungal cases are excluded. The development of a new murmur of valvular regurgitation in 18 patients led to valve replacement or death in every patient. Streptococcal endocarditis in 11 patients resulted in no deaths and only two valve replacements; staphylococcal infections had a mortality of 27.1 percent (6/22). Length of medical therapy before valve replacement did not relate to a successful outcome. Eight cases of early staphylococcal endocarditis occurred in which the organism was susceptible to the prophylactic antibiotic therapy. Changes in prophylaxis have led to no cases of early endocarditis over the past three years in 261 valve replacements.

Surgical management of native valve endocarditis

From 1972 to 1981 40 patients have required urgent valve replacement for left-sided bacterial endocarditis. The aortic valve was replaced in 31 patients, the mitral valve in four, and both in five patients. Twenty-six patients (65.5%) were in functional class IV heart failure according to the New York Heart Association criteria, and 13 patients (32.5%) were in class III heart failure at the time of operation. One patient in class II was operated on urgently for multiple cerebral embolism but died of fatal cerebral haemorrhage. In 22 patients (55%) there were no pre-existing valvular lesions and these patients were found to be more liable to develop severe haemodynamic failure. Premature closure of the mitral valve, documented by M-mode echocardiography, was a useful diagnostic aid and successfully determined the best timing of surgery in 14 out of 20 patients with severe aortic regurgitation. Cardiac arrest before operation appeared to be a significant risk factor (p = 0.0015) unless followed by immediate cardiopulmonary bypass. There were eight operative deaths (20%). Of 26 patients who were in functional class IV heart failure, 19 were operated on within four days of their haemodynamic deterioration and all survived. The operation was delayed in the remaining seven patients and none of them survived (p = 0.000003). There were no operative deaths among the patients in class III heart failure. There was only one episode of reinfection in the 16 patients followed up for at least three years. The duration of postoperative antibiotic treatment (four to six weeks in our patients), rather than any preoperative antibiotic regimen, seems to be important for preventing reinfection. At present there are 28 survivors, of whom 24 are in functional class I and four in class II.

Evaluation and management of prosthetic valve endocarditis

Despite improved operative technique and sophistication in managing patients undergoing cardiac valve replacement, prosthetic valve endocarditis (PVE) remains a source of major morbidity (overall recent incidence approximately 2.1%), and these patients have a high case-fatality rate (58% overall). Early PVE (less than 60 days postoperative) has a worse prognosis (78% case-fatality rate) and is usually caused by staphylococcal species, gram-negative rods, and fungi; whereas the case-fatality rate in late PVE is 46%, owing to the lower fatality of streptococcal species infections that tend to occur late. Risk factors that portend a poor clinical response to medical therapy alone include the presence of congestive heart failure, paravalvular leakage, systemic embolic, early PVE, nonstreptococcal etiology, aortic location in a nonheterograft valve, as well as persistent fever (greater than 10 days). Given the frequently dismal outcomes in the medical management of these patients, the case is made for early surgical intervention in most cases of PVE (except for late streptococcal disease), especially if any of the aforementioned risk factors are present.

Ten years' experience with pulmonary autograft replacements for aortic valve disease

Pulmonary autograft valves have been used to replace isolated, diseased aortic valves for 10 years, with a long-term survival of 73%. The low incidence of degeneration supports the principle that the autograft valve is a potentially permanent valve replacement. Operative mortality is now less than 5%, despite the longer, more complex operation. The current use of fresh homograft valves for the pulmonary replacement has contributed to these excellent long-term results.

Infection of glutaraldehyde-preserved porcine valve heterografts

Gross, histologic and ultrastructural changes associated with bacterial infection are described in four porcine valve heterografts that had been in place in patients for 6 days to 28 months. In one patient, culture of the aortic tissue tag included in the heterograft container grew Mycobacterium chelonei; however, examination of the heterograft, recovered at necropsy 6 days after implantation, revealed small colonies of bacteria that differed morphologically from mycobacteria. A second heterograft was the site of staphylococcal infection associated with extensive destruction of collagen in the leaflets. Similar destruction was observed in a third heterograft, which was found to have organisms on ultrastructural study even though bacterial cultures of the valve were negative. The fourth heterograft, from a patient who died of coronary embolism secondary to dislodgment of vegetative material, contained structures resembling lysed bacteria. Observations in these 4 patients and review of published reports of infection involving 43 other patients with porcine valve heterografts indicates that infection in these valves: (1) develops in the fibrin layer that covers the cusps, (2) can involve the collagen in the leaflets, and (3) is uncommonly (three patients) associated with valve ring abscesses.

Valve replacement in patients with active infective endocarditis

Eleven of 138 patients with infective endocarditis (IE) who underwent cardiac valve replacement for IE during a 12 1/2-year period had active IE. Eight of the 11 (all with aortic IE) had positive blood cultures within 48 hours preoperatively; six of the eight had positive Gram stains and cultures of the excised cardiac tissue. All 11 patients had Class IV cardiac functional disability (New York Heart Association classification) at the time of surgery. Staphylococci (three patients with Staphylococcus aureus and one with S. epidermidis) were the most frequent isolates. Three patients died; two of these three deaths occurred in patients who had a sudden onset preoperatively of severe aortic regurgitation and heart failure. In one patient (S. epidermidis infection) prosthetic valve endocarditis developed. Cardiac valve replacement may be performed successfully in patients with active IE even when blood cultures are positive in the immediate perioperative period. The hemodynamic status of patients with IE should be the determining factor in the timing of cardiac valve replacement, rather than the activity of the infection or the length of preoperative antimicrobial therapy. A radical surgical procedure may be necessary in patients with myocardial or aortic abscesses in whom conventional aortic valve replacement is not possible.

The determinants of survival following reoperation on prosthetic cardiac valves

In an effort to identify the determinants of survival following reoperation on patients with prosthetic cardiac valves, the experience with a group of 33 patients at the University of Rochester Medical Center was reviewed. The survival rate was 58% (19/33). Survival was not related to the valve involved, the age of the patient, or the technical hazards of a second cardiac operation. Ten (77%) of the 13 patients in New York Heart Association (NYHA) Functional Class II survived compared with 8 (40%) of the 20 in Class III or IV. The survival rate for patients with a paravalvular fistula was 79% (11/14); with valve dysfunction, 50% (6/12); and with prosthetic valve infection, 29% (2/7). The determinants of survival seem to be similar to those for primary operation (i. e., NYHA patient classification and indication for operation) and less related to the potential operative complications of a reoperation.

Changing concepts in management of infective endocarditis

Sixty-four patients were treated for 73 episodes of infective endocarditis over the five-year period 1970 to 1974 at St Vincent's Hospital, Sydney. There were 13 deaths with a mortality rate of 18-1% compared with 38% (1950 to 1959). Included were 13 cases of infection on prosthetic valves with three deaths. Fifty-one per cent of patients were studied by cardiac catheterization. Early or emergency surgery was performed in 28% of cases and late surgery in 16%. The improved results were due to multiple factors, including early diagnosis, prompt investigation in a specialized unit, rational use of appropriate antibiotics, careful management of complications and early surgery.

The epidemiology of 2056 remote site infections and 1966 surgical wound infections occurring in 1865 patients: a four year study of 40,923 operations at Rush-Presbyterian-St. Luke's Hospital, Chicago

Over a 4-year period 40,923 operations and 44,716 surgical admissions were monitored for both community and hospital onset infections. One thousand eight hundred sixty-five patients had 1966 surgical wound infections and 2056 remote infections including 1652 hospital onset and 404 community onset infections. One thousand one hudnred forty-four patients with multiple infections averaged 40 days in the hospital contrasted with 24 days for 721 patients with a single wound infection. The total excess cost of hospitalization for these patients was $951,150. A statistically significant reduction occurred for urinary tract infections, lower respiratory infections and clean and contaminated surgical wound infections. It is suggested that these are all inter-related and a significant reduction in surgical wound infections can be achieved through control of infections at remote sites, particularly those associated with medical devices. The coagulase positive staphylococcus is still the most important single bacterial species in the primary etiology of surgical wound infections. When the gastrointestinal tract is entered or "supra" infecting organisms appear, gram negative bacteria and mixed gram negative and gram positive infections are dominant. Reduction in remote site infections occurring in surgical patients is necessary to reduce the incidence of surgical wound infections, suggest preventive and control measures, and document the effectiveness of such measures.