Infective Endocarditis

1
Infective Endocarditis

• Suhail Allaqaband
• Sinai Samaritan Medical Center
• Milwaukee, WI

2
EPIDEMIOLOGY

• An estimated 10,000 to 15,000 new cases of IE are
  diagnosed in the United States each year
• IE has increasingly become a disease of the
  elderly
• More than one-half of all IE cases in the United
  States now occur in patients over the age of 60
• This trend is probably due to two factors
• the decline in the incidence of rheumatic heart
  disease
• the increasing proportion of elderly subjects in
  the general population

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RISK FACTORS

• Injection drug use
• Highest risk factor in patients lt 40 years of age
• Prosthetic heart valves
• Prosthetic valve endocarditis comprises a small
  but important segment of IE cases
• More than 100,000 heart valves are implanted
  annually in the United States
• IE develops in 1 to 4 of valve recipients
  during the 1st year following valve replacement,
  and in approximately 1 percent per year
  thereafter

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RISK FACTORS

• Nosocomial endocarditis
• Usually a complication of bacteremia induced by
  an invasive procedure or a vascular device
• Structural heart disease
• Approximately three-fourths of all patients with
  IE have a preexisting structural cardiac
  abnormality
• Congenital heart disease is present in 10-20
  cases
• The most common predisposing congenital heart
  lesions are bicuspid aortic valves, PDA, VSD,
  coarctation of the aorta, and tetralogy of Fallot

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RISK FACTORS

• Degenerative valvular lesions
• The risk of IE in patients with MVP and
  associated regurgitation is estimated to be 5 to
  8 times higher than that in the normal population
  
• Aortic valve disease(stenosis or/and
  regurgitation) is present in 12 to 30 percent of
  cases

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RISK FACTORS

• History of infective endocarditis
• Recurrent endocarditis occurred in 4.5 percent of
  one large cohort of non-addicts
• Other studies have reported rates of IE
  recurrence ranging from 2.5 to 9 percent
• HIV infection
• A number of cases of IE have been reported in
  patients with HIV infection
• It has been suggested that HIV infection is an
  independent risk factor for IE in IV drug abusers

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• A number of other, less common predisposing
  factors for IE include
• Pregnancy
• AV fistulas used for hemodialysis
• Central venous and pulmonary artery catheters
  
• Peritoneovenous shunts for the control of ascites
• Ventriculoatrial shunts for the management of
  hydrocephalus
• In addition, patients with ulcerative lesions of
  the colon due to carcinoma or inflammatory bowel
  disease have a poorly understood predilection to
  develop endocarditis secondary to Strep.bovis

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Case Definition

• Duke criteria
• In 1994 investigators from Duke University
  modified the previous criteria to include the
  role of echocardiography in diagnosis
• They also expanded the category of predisposing
  heart conditions to include intravenous drug use

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Duke Criteria

• Definitive infective endocarditis
• pathologic criteria
• microorganisms demonstrated by culture or
  histology in a vegetation, or in a vegetation
  that has embolized, or in an intracardiac abscess
  or
• Pathologic Lesions vegetation or intracardiac
  abscess, confirmed by histology
• clinical criteria
• two major criteria, or
• one major and three minor criteria, or
• five minor criteria

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Duke Criteria

• Possible infective endocarditis
• findings consistent of IE that fall short of
  definite, but not rejected
• Rejected
• firm alternate Dx for manifestation of IE
• resolution of manifestations of IE, with
  antibiotic therapy for ? 4 days
• no pathologic evidence of IE at surgery or
  autopsy, after antibiotic therapy for ? 4 days

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Duke Criteria

• Major criteria
• positive blood culture for IE
• evidence of endocardial involvement
• Minor criteria
• predisposition (heart condition or IV drug use)
• fever of 100.40F or higher
• vascular or immunologic phenomena
• microbiologic or echocardiographic evidence not
  meeting major criteria

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Major Criteria

• Positive blood culture for IE
• typical microorganism for IE from two separate
  blood cultures in the absence of a primary focus
• strep viridans, strep bovis, HACEK group, staph
  aureus or enterococci
• Persistently positive blood culture
• blood cultures drawn more than 12 hr apart, or
• all of 3 or a majority of 4 or more separate
  blood cultures, with first and last drqwn at
  least 1 hr apart

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Major Criteria

• Evidence of endocardial involvement
• positive echocardiogram for endocarditis
• oscillating intracardiac mass on valve or
  supporting structure, or in the path of
  regurgitant jets, or on implanted material, in
  the absence of an alternate anatomic explanation
• abscess
• new partial dehiscence of prosthetic valve
• new valvular regurgitation (increase or change in
  pre-existing murmur not sufficient)

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Minor Criteria

• predisposition
• predisposing heart condition or iv drug use
• fever of 100.40F or higher
• vascular phenomena
• major arterial emboli
• septic pulmonary infarcts
• mycotic aneurysm
• intracranial hemorrhage
• conjunctive hemorrhages
• Janeway lesions

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Dukes Minor Criteria

• immunologic phenomena
• Glomerulonephritis
• Rheumatoid factor
• microbiologic evidence
• positive blood culture not meeting major criteria
  or serologic evidence of active infection with
  organism consistent with IE
• echocardiogram
• consistent with IE but not meeting major criteria

• Oslers nodes
• Roth spots

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Validity of Duke criteria

• 405 consecutive cases of suspected IE were
  studied
• 69 cases of IE were confirmed pathologically
• 55 (80 percent) were clinically classified as
  definite using the Duke criteria, versus only 35
  being classified as probable by the von Reyn
  criteria
• 12 of the pathologically confirmed cases were
  "rejected" by the von Reyn criteria whereas none
  by the Duke criteria
• New criteria for diagnosis of infective
  endocarditis Utilization of specific
  echocardiographic findings.
• Duke Endocarditis Service Am J Med 1994 96200

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Diagnostic approach to infective endocarditis

• History
• A careful history should be performed with
  special attention given to a history of prior
  cardiac lesions and historical clues pointing
  toward a recent source of bacteremia
• Physical examination
• A meticulous clinical examination should be
  performed looking for clinical evidence of small
  and large emboli with special attention to the
  fundi, conjunctivae, skin, and digits
• Cardiac examination may reveal signs of new
  regurgitant murmurs and signs of CHF
• Neurologic evaluation may detect evidence of
  focal neurologic impairment

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Diagnostic approach to infective endocarditis

• Positive blood culture results
• A minimum of three blood cultures should be
  obtained over a time period based upon the
  severity of the illness
• Additional laboratory tests
• An elevated ESR and/or an elevated level of CRP
  is usually present
• Most patients quickly develop a normochromic
  normocytic anemia
• The WBC count may be normal or elevated

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Diagnostic approach to infective endocarditis

• Additional laboratory tests
• elevated levels of serum globulins
• presence of cryoglobulins and circulating immune
  complexes
• hypocomplementemia
• false positive serologic tests for syphilis
• abnormal urinalysis
• microscopic or gross hematuria, proteinuria, or
  pyuria
• the combination of RBC casts on urinalysis and a
  low serum complement level may be an indicator of
  immune-mediated glomerular disease

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Diagnostic approach to infective endocarditis

• Electrocardiogram
• All patients with suspected IE should have an EKG
  to determine whether there is evidence of heart
  block or a conduction delay and to establish a
  baseline should such a complication develop later

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Diagnostic approach to infective endocarditis

• Echocardiography
• Should be performed in all patients with
  suspected IE
• A TTE should initially be obtained in patients
  with native heart valves, while those with
  prosthetic valves should undergo TEE
• Detection of a vegetation by TTE is a positive
  test
• However, a negative study does not preclude the
  diagnosis and should be followed by TEE, when
  there is an intermediate or high suspicion of IE

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Improved diagnostic value of echocardiography in
patients with infective endocarditis by
transoesophageal approach A prospective
study.Eur Heart J 1988 Jan9(1)43-53

• 96 patients were studied consecutively with TEE
  and TTE
• TEE had a sensitivity for the detection of
  vegetations of 100 percent as compared to 63
  percent with TTE
• Both TTE and TEE had specificity of 98
• Only 25 of vegetations less than 5 mm, 69 of
  vegetations 6-10 mm, and 100 of vegetations
  greater than 11 mm detected by TEE were also
  observed with TTE

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Major Pathogens

• Native Valve IE
• Strep.(55), mostly Viridans
• Staph.(30), mostly S.aureus
• Entrococci(5-10)
• Prosthetic Valve IE
• Early (0-2 months)
• Staph(50)- mostly S.epi.
• IE in IV drug abusers
• Staph. aureus(50-60)

• Late (gt60 days)
• Staph(30)

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Treatment of infective endocarditis

• GENERAL CONSIDERATIONS
• Antimicrobial therapy should be administered in a
  dose designed to give sustained bactericidal
  serum concentrations throughout much or all of
  the dosing interval
• In vitro determination of the minimum inhibitory
  concentration of the etiologic cause of the
  endocarditis should be performed in all patients

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Treatment of infective endocarditis

• GENERAL CONSIDERATIONS
• The duration of therapy has to be sufficient to
  eradicate microorganisms growing within the
  valvular vegetations
• The need for prolonged therapy in treating
  endocarditis has stimulated interest in using
  combination therapy to treat endocarditis

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VIRIDANS STREPTOCOCCI AND STREP. BOVIS

• Antibiotic Dosage and route Duration Comments
• Aqueous crystalline 12-18 million U/24 h 4
  wks preferred in most patients older than 65 yrs
• penicillin G sodium IV either continuously and
  in those with impairment of the eighth
• or in 6 divided doses nerve or renal
  function
• or
• Ceftriaxone sodium 2g once daily IV or IM 2 wks
• Aqueous crystalline 12-18 million U/24 h 2
  wks when obtained 1h after a 20-30 min.
• penicillin G sodium IV either continuously IV
  infusion or IM injection, serum
• or in six equally concentration of gentamicin
  of
• divided doses approximately 3 mcg/mL is
  desirable
• with gentamicin 1 g IM or IV every 8 h 2
  wks trough concentration should be lt 1 pg/mL
• sulfate
• Vancomycin 30 mg/kg per 24 h IV 4 wks vancomycin
  therapy is recommended for
• hydrochloride in two equally divided patients
  allergic to beta lactams peak doses, not to
  exceed 2 serum concentrations of vancomycin
  should
• gram/24h unless serum be obtained one h after
  completion of the
• levels are monitored infusion and should be in
  the range of

JAMA 1995 2741706
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ENTEROCOCCI
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STAPH. ENDOCARDITIS IN NATIVE VALVES
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STAPH. ENDOCARDITIS IN PROSTHETIC VALVES
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HACEK ORGANISMS
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Indications for surgery in IE

• The indications for surgery in patients with
  native-valve IE and prosthetic-valve IE are
  essentially the same
• Surgery is warranted for patients with active IE
  who have one or more of the following
  complications
• CHF that is directly related to valve dysfunction
• Persistent or uncontrolled infection while
  receiving appropriate antimicrobial therapy,
  including evidence of perivalvular extension
• Recurrent emboli, particularly in the presence of
  large vegetations

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Indications for surgery in IE

• Relative indications for surgery
• Evidence of perivalvular infection, such as
  intracardiac abscess or fistula formation
• Rupture of a sinus of Valsalva aneurysm
• Fungal endocarditis
• Endocarditis due to highly resistant
  microorganism
• Relapse after a course of adequate antimicrobial
  therapy, particularly in prosthetic valve
  endocarditis
• Culture-negative IE with fever more than 10 days
  after starting empirical therapy

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Indications for surgery in prosthetic valve IE

• Same as native valve endocarditis
• Perivalvular infection
• Valve Dehiscence
• excessively mobile prosthesis on echo
• results in hemodynamic instability

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OUTCOME OF SURGERY

• The outcome of surgery in patients with IE has
  been good, particularly when surgical treatment
  is radical with the removal of all infected and
  necrotic tissue
• In a recent study of 138 patients who underwent
  valve surgery in the presence of active
  infection, the early mortality, due to heart
  failure or septic multiorgan failure, was 11.5
• Risk factors for early mortality were NYHA class
  IV or cardiogenic shock, advanced age,
  preoperative acute renal failure, and
  staphylococcal infection
• Operation for infective endocarditis Results
  after implantation of mechanical valves. Ann
  Thorac Surg 1998 65359.

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ACC/AHA recommendation for surgery in patients
with native valve endocarditis
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ACC/AHA recommendation for surgery in patients
with prosthetic valve endocarditis
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ACC/AHA recommendation for valve replacement with
mechanical prosthesis
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ACC/AHA recommendation forvalve replacement with
bioprosthesis