Transcript INFECTIVE ENDOCARDITIS
INFECTIVE ENDOCARDITIS
Manoj Kuduvalli
Definition
Bacterial or Fungal infection within the heart (although chlamydial and rickettsial infections are known) ; the role of viruses is unknown
ORIGINAL CLASSIFICATION
(Prior to Antibiotic era)
Infective Endocarditis
Acute Virulent Organisms Normal Valve Death < 6 weeks Subacute Relatively avirulent organisms Abnormal valve Indolent course
Current Criteria for Classification
Underlying Anatomy: › Native Valve Endocarditis › Prosthetic Valve Endocarditis Infecting Organism › Serves as basis for therapy and prognosis
Native Valve Endocarditis Underlying Predisposing Conditions ›› 60 - 80% of non IV Drug abusers have a predisposing condition › Mitral Valve Prolapse 30 - 50% › Rheumatic Heart Disease 20 - 40% › Degenerative Aortic and 20 - 30% Mitral valve disease › Congenital Heart Disease 10 - 20%
Native Valve Endocarditis Microbiology ›› Streptococci 50 - 70% Viridans Streptococci (50% of all Strep) ›› Staphylococci ~ 25% Mostly Coagulase +ve Staph. Aureus Staph. Epidermidis ›› Enterococci ~ 10%
Native Valve Endocarditis Microbiology
Viridans Streptococci
Infect primarily abnormal valves Indolent clinical course Highly sensitive to Penicillins
Staph. aureus
Infect normal and abnormal valves
Fulminant course with rapid destruction of valves and multiple metastatic abscesses Mostly resistant to Penicillins and sensitive to penicillinase resistant ß-lactams Common with soft tissue infections, and infected IV catheters
Native Valve Endocarditis Microbiology
Staph. Epidermidis
Indolent Course
Affects abnormal valves
Enterococci
Normally affects damaged valves Recent history of genitourinary or gastrointestinal manipulation, disease or trauma Usually sensitive to Penicllin+Gentamicin Resistant strains prevalent
Prosthetic valve endocarditis
5 - 15% of all Infective Endocarditis
Overall incidence 1 - 4%
Risk of PVE peaks at 15 days postop. , then rapidly declines by 150 days
Prosthetic Valve Endocarditis Classification
Early ( < 60 days )
Late ( > 60 days)
Reflects perioperative contamination Incidence around 1% Microbiology
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Staph (45 - 50%)
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Staph. Epiderm (~ 30%)
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Staph. Aureus (~ 20%)
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Gram -ve aerobes (~20%) Fungi (~ 10%) Strep and Entero (5-10%)
After endothelialization Incidence 0.2 -0.5 % / pt. year Transient bacteraemia from dental, GI or GU Microbiology
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resembles native valve endocarditis
IE in IV Drug Abusers
Right sided predilection Tricuspid Valve Aortic Valve Mitral Valve Pulmonary Valve ~ 55% ~ 25% ~ 20% 1 - 1.5% Mixed Rt. And Lt. Side 5 - 6%
IE in IV Drug Abusers
Skin most predominant source of infection
Also contamination of drugs and paraphernalia
70 - 100% of Rt. sided IE results in pneumonia and septic emboli
Microbiology
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Staph aureus Streptococci and Enterococci Gram -ve bacilli Fungi (Candida and Aspergillus ~60% ~20% ~10% ~5%
IE in adults with congenital heart disease
Common defects VSD PDA Bicuspid AV PS Coarctation of Aorta Occurs in defects with --mild or no hemodynamic consequences --high gradients --high velocity jets impinging on endocardium
Microbiology very important since virulence of the infecting organism is a significant factor in determining the success rates of both medical and surgical treatment
Pathogenesis
Requires interaction between › Host vascular endothelium › Host haemostatic response › Adventitiously circulating organisms
Pathogenesis of Vegetations
Hemodynamic factors predisposing to Infective Endocarditis
High velocity abnormal jet stream
Flow from high to low pressure chamber
Narrow orifice between two chambers creating pressure gradient
Pathology
Local intracardiac infectious process Embolization Immune complex associated disease
Leaflet perforation VSD
Pathology
Intracardiac infections Rupture of chordae Valve ring abscesses Burrowing abscesses Conduction abnormalities Purulent pericardial effusions Fistulae Aneurysm of Sinus of Valsalva
Common sites of origin of extravalvular spread
Valve leaflets in native valve endocarditis Can extend into annulus
Pathology
Initially affects Annulus in prosthetic valve endocarditis Due to presence of sewing rim
Pathology -
Embolic Phenomena
Incidence
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Clinically Pathologically 15 - 45% 45 - 65%
More with large mobile vegetations
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Fungi (Candida and Aspergillus) Group B and G Streptococci Staph aureus
Result in
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Infarcts
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Abscesses Mycotic aneurysms
Pathology
Immune Complex Associated
Glomerulonephritis
Arthritis
Osler’s nodes
Clinical Features
Onset usually within 2 weeks of infection
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Indolent course - Malaise - Fatigue - Night sweats - Anorexia - Weight loss › Explosive course - CCF - S/o severe systemic sepsis
Clinical features
› Fever - Usually < 39 °C, remittent - May be absent in - elderly - severe debility - CCF › Murmurs - Already on antibiotics - Appearance of new murmur or true change in existent murmur indicates infection with virulent organism
Other Clinical Features
Splenomegaly ~ 30%
Petechiae
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Conjunctivae Buccal mucosa
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palate skin in supraclavicular regions Osler’s Nodes 20 - 40% 10 - 25%
Splinter Haemorrhages 5 - 10%
Roth Spots
Musculoskeletal (arthritis) ~ 5%
Complications
Congestive Cardiac Failure (Commonest complication)
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Valve Destruction
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Myocarditis
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Coronary artery embolism and MI
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Myocardial Abscesses
Neurological Manifestations (1/3 cases)
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Major embolism to MCA territory
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Mycotic Aneurysms ~25% 2 - 10%
Complications
Metastatic infections
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Rt. Sided vegetations
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Lung abscesses Pyothorax / Pyopneumothorax
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Lt. Sided vegetations
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Pyogenic Meningitis Splenic Abscesses
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Pyelonephritis Osteomyelitis Renal impairment d/t Glomerulonephritis
Diagnosis
Blood Cultures
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Positive in 95% cases
Other Laboratory Parameters
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Anaemia
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Leucocytosis (WCC may be normal in indolent infection)
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Thrombocytopenia
ESR (may be absent in CCF and renal failure) Urine - Microscopic hematuria / proteinuria
Echocardiography
Can demonstrate lesion / vegetation in 60 80% of cases
Difficult in prosthetic valve endocarditis
TOE better than TTE
Can demonstrate
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Morphology of valve Annular abscesses Hemodynamics of the valves
Serial observations can contribute to decision for surgery
Treatment
Medical Surgical
Principles of Medical Management
Sterilization of Vegetations with antibiotics - prolonged Slowly metabolising bacteria due to high density, hence
sensitivity - high dose Bacteria deep inside vegetations -bactericidal
Principles of Medical Management
Acute onset, fulminant -Within two to three hours of clinical diagnosis. -Take cultures, but do not wait for results Timing of Therapy Subacute onset, or having received recent antibiotic -Within two to three days.
-Can wait for culture reports
Principles of Medical Management
Isolation of organisms very important
Therapy before isolation of organism
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Native valve endocarditis and in IV drug abusers
Directed against Staph aureus
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Prosthetic valve endocarditis
Broad spectrum antibiotics directed against
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Staph aureus Staph epidermidis Gram –ve bacilli
Indications for Surgery
Left sided native valve endocarditis
Valvular disruption leading to severe insufficiency and CCF
Extravalvar extension
Embolization of vegetations
Failure of medical management Positive blood culture and systemic signs of infection after “adequate” antibiotic therapy
Resistant organisms such as MRSA, Fungi , Pseudomonas
Echo detected vegetation > 1 cm ??
Indications for Surgery
Right sided native valve endocarditis Indications differ because: - Consequences of valve disruption and emboli are less - Success with antibiotics seems to be better Indications --Failure of medical treatment --CCF, with its complications (elective) --Recurrent pulmonary emboli with complications --Extravalvar spread (rare)
Indications for surgery
Prosthetic valve endocarditis
Early infection almost always require surgery
Late infection Antibiotic therapy succeeds more often with Bioprosthesis compared to mechanical valves Indications CCF due to prosthesis dysfunction Multiple emboli Persistent infection
Indications for Surgery Special situations
AIDS Not usually indicated since life expectancy due to AIDS very poor HIV +ve patient without AIDS IV Drug Abusers No change in indications since enough number survive > 10 years
When to operate ?
As soon as there is a major indication Valid reasons for delay Acute CNS injury - Hemorrhagic infarct (Wait for 10 days to allow healing) --Coma (very poor prognosis ) Renal failure due to Glom’nephritis Follow through the acute phase (Prerenal failure -- early operation)
Principles of operation
Repair or Replacement ?
(More important with mitral valves) Repair contemplated only if: --Infection well controlled --Repair structurally feasible after involved tissue excised
Principles of operation
Early operation once indicated
Preop. knowledge of morphology of valve
Good exposure mitrals) (may be difficult in
Excision and debridement of all infected or involved tissue even if extensive reconstruction or permanent pacing required
Principles of operation
Look for extravalvar extension
If present, evacuate abscess cavity and repair with biological material such as autologous or bovine pericardium
Suture valve onto clean and relatively strong tissue
Temporary pacing leads
Mechanical Which Prosthesis?
Stented Bioprosthesis Stentless Bioprosthesis Homograft
Choice of prosthesis
Important factor is location of infection -- Infection of cusps only: Choice does not matter, since all infected tissue is usually excised -- Perivalvar extension: No choice between mechanical and stented bioprosthesis (both with cloth sewing rims) Homograft, maybe stentless bioprosthesis have lesser incidence of infection
Choice of prosthesis
Mechanical v/s Bioprosthetic
No difference in linearized rates for recurrent or residual infection (~1-2% per patient year)
No difference in operative mortality and complication free survival
Infected bioprosthesis more easily sterilized (since infection initially involves leaflets)
However, infection in bioprosthesis may hasten SVD due to damage to leaflets
Choice of prosthesis
Homograft v/s others
Hazard function for recurrent endocarditis has only low constant phase and has no high early hazard phase like other prosthesis
Homograft best choice if valved conduit is required for root replacement ( > 50% annular dehiscence or aortoventricular discontinuity)
Postoperative Antibiotics
To continue for 6 weeks if › Operated for - Acute fulminant infection --Failure of medical therapy --Resistant organisms › Excised valve yields positive cultures › Periannular involvement › Valve culture –ve, but organisms seen on histology › Positive blood cultures 3 – 4 days postop.
Results of Treatment
Native valve endocarditis Medical Management Mortality 10 – 60 % Risk Factors Virulent organisms s/a MRSA, G-ve bacilli, fungi CCF Persistence of systemic sepsis Major septic embolus Extravalvar extension Acute renal failure
Results of Treatment
Native valve endocarditis Surgical Management Hospital Mortality 5 – 20% Risk factors Virulent organisms Perivalvar extension Intractable CCF Renal and multiorgan failure
Results of Treatment
Native valve endocarditis Surgical Management Recurrent Endocarditis ~ 2% Most occurs within 2 months post op.
Same organism No fresh source of infection Perivalvar leaks 3-7%
Results of Treatment
Prosthetic valve endocarditis Medical Management Mortality ~ 70% Risk factors Valve incompetence or perivalvar leak Early postoperative onset Virulent organism
Results of Treatment
Prosthetic valve endocarditis Surgical Management Hospital Mortality 0 –22% Risk factors Early postoperative infection Virulent organism Perivalvar extension Delay in operation
Results of Treatment
Prosthetic valve endocarditis Surgical Management
Long term results differ from valve replacement for NVE or other lesions
Have comparatively unfavourable rates of late death, recurrence of infection and reoperation
Antibiotic Prophylaxis
Protocol usually followed recommended by Dajani et al in JAMA 1990 Recommended in following conditions Prosthetic valves Previous history of infective endocarditis (even without underlying heart disease) Most congenital heart diseases Rheumatic or other acquired valve disease IHSS MVP with MR