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prosthetic heart valves

Prosthetic Heart Valves

Dr. Mona Youssef

http://www.cardiologylinks.webs.com/home

complications
complications
  • Primary valve failure
  • Prosthetic valve endocarditis (PVE)
  • Prosthetic valve thrombosis (PVT)
  • Thromboembolism
  • Mechanical hemolytic anemia
  • Anticoagulant-related hemorrhage
make up
Make UP
  • Composition:

- Synthetic material (mechanical prosthesis)

- Biological tissue (bioprosthesis).

- Homografts or preserved human aortic valves

  • Three main designs :

- Caged ball valve

- Tilting disc (single leaflet) valve

- Bileaflet valve.

*The only Food and Drug Administration (FDA)–approved caged ball valve is the Starr-Edwards valve

bioprosthetic xenograft valves
Bioprosthetic (xenograft) valves

Made from:

  • Porcine valves e.g. Carpentier-Edwards valves

or

  • Bovine pericardium e.g. Perimount series

valves

valve failure
Valve failure
  • Abruptly:

-Tearing e.g. suture line dehiscence or

breakage of components with acute valvular

regurgitation or embolization of the valve

fragments

-Thrombus suddenly impinging on leaflet

mobility

  • Gradually:

- Calcifications with stiffening of the leaflets

- Thrombus / pannus formation

acute mitral valve failure
Acute Mitral Valve Failure
  • Sudden left atrial volume overload
  • Increased left atrial pressure
  • Pulmonary venous congestion
  • Pulmonary edema
  • Decreased left ventricular output due to regurgitatnt volume into the left atrium
  • The compensatory mechanism of increased sympathetic tone:

- Increases the heart rate and the systemic vascular

resistance (SVR)

- Decreases diastolic filling time

- Impedes left ventricular outflow

- Increases the regurgitant volume

acute aortic valve failure
Acute Aortic valve Failure
  • Rapidly progressive left ventricular volume overload
  • Increased left ventricular diastolic pressure
  • Pulmonary congestion and edema
  • Decreased cardiac output
  • The compensatory mechanism of increased sympathetic tone:

- Increases heart rate and yields a positive inotropic state,

aiding in the maintenance of cardiac output

BUT also:

-increases SVR impeding forward flow

-Increases systolic wall tension yielding a rise in myocardial

oxygen consumption& Myocardial ischemia, even in the absence

of coronary artery disease.

bioprosthesis
Bioprosthesis
  • Mostly suffer from slow degeneration, calcification, or thrombus formation
  • Asymptomatic
  • gradually worsening congestive heart failure, with increasing dyspnea.
  • Unstable angina
  • Systemic embolization
slide13
Early PVEoccurring within 60 days of implantation Due to: perioperative contamination or hematogenous spread
  • Charecteristic lesion in mechanical valves : ring abscesses

*Ring abscess may lead to:

- Valve dehiscence and perivalvular leakage

- Local extension with formation of myocardial abscesses

- Further extension to the conduction system producing a new

atrioventricular block

- Less frequently valve stenosis and purulent pericarditis

  • Bioprosthetic valve PVE usually causes leaflet tears or perforations. Valve stenosis is more common with bioprosthetic valves than with mechanical valves. Ring abscess, purulent pericarditis, and myocardial abscesses are much less frequent in bioprosthetic valve PVE.
  • Finally: glomerulonephritis, mycotic aneurysms, systemic embolization, and metastatic abscesses
incidence
Incidence
  • Prosthetic valve thrombosis is more common in mechanical valves
  • Thromboembolic complication rates:

- Hightest in Caged ball valves

- Lowest in bileaflet valves

  • Valve thrombosis is increased with:

- Valves in the mitral position

- In patients with subtherapeutic anticoagulation.

  • Anticoagulant-related hemorrhagic complications :

- Major hemorrhage in 1-3% of patients per year

- Minor hemorrhage in 4-8% of patients per year.

slide17
hemolytic anemia

- Low-grade in 70% of prosthetic heart valve recipients

- Severe hemolytic anemia occurs in 3%

*The incidence is increased with caged ball valves and

in those with perivalvular leaks.

  • Primary valve failure occurs in:

- 3-4% of patients with bioprostheses within 5 years of

implantation and in up to 35% of patients within 15 years.

- Mechanical valves have a much lower incidence of primary

failure.

  • PVE occurs in 2-4% of patients:

- 3% in the first postoperative year, then 0.5% for subsequent

years.

- The incidence is higher in mitral valves.

- Mechanical and biological valves are equally susceptible.

mortality morbidity
Mortality/Morbidity
  • Acute failure of a prosthetic aortic valve usually leads to sudden or near-sudden death.
  • PVE has an overall mortality rate of 50%.
  • In early PVE, the mortality rate is 74%.
  • In late PVE, the mortality rate is 43%.
  • The mortality rate with a fungal etiology is 93%.
  • The mortality rate for staphylococcal infections is

86%.

  • Fatal anticoagulant-induced hemorrhage occurs in 0.5% of patients per year.
slide19
Age
  • The incidence of having any prosthetic valve complication decreases with age.
  • In children, bioprostheses rapidly calcify and undergo rapid degeneration and valve dysfunction.
  • Bioprosthetic failure is much higher in patients younger than 40 years.
history
History
  • Sources include a wallet-sized identification card (typically given to the patient at the time of surgery) and/or a review of medical records.
  • Symptoms depend on the type of valve, its location, and the nature of the complication.

-With valvular breakage or dehiscence, failure often

occurs acutely with rapid hemodynamic

deterioration.

-Failure occurs more gradually with valve thrombosis,

calcification, or degeneration.

  • Heavily calcified or infected valvular annulus is suggestive of a perivalvular leak
  • Acute prosthetic valve failure often present with the sudden onset of dyspnea, syncope, or precordial pain.
slide22
Subacutevalvular failure maybe asymptomatic/ present with:

- Gradually worsening congestive heart failure.

(increasing dyspnea with exertion, orthopnea,

paroxysmal nocturnal dyspnea, and fatigue)

- Unstable angina

  • Embolic complications have symptoms related to the site of embolization:

- Stroke

-Myocardial infarction (MI)

- Sudden death

- Symptoms of visceral or peripheral embolization.

  • Anticoagulant-related hemorrhage symptoms are related to the site of hemorrhage.
  • PVE: Fever
physical exam
Physical Exam
  • Normal prosthetic heart valve sounds
    • Mechanical valves:

.Tilting disc and bileaflet valves:

*A loud, high-frequency, metallic closing sound.

Can frequently be heard without a stethoscope

Absence of this distinct closing sound is abnormal and implies

valve dysfunction

* +/- a soft opening sound

.Caged ball valves (Starr-Edwards) have low-frequency opening and

closing sounds of nearly equal intensity.

    • Tissue valves: Closing sounds are similar to those of native valves. A low-frequency early opening sound may present in the mitral position.

*Muffled or absent normal prosthetic heart sounds may be a clue to valve

failure or thrombosis.

slide24
Prosthetic heart valve murmurs
    • Aortic prosthetic valves

-Smaller orifice size always yields some degree of outflow obstruction

producing a systolic ejection murmur

- The intensity of the murmur increases with rising cardiac output

- Caged ball and small porcine valves produce the loudest murmurs

- Tilting disc valves and bileaflet valves upon closure do not occlude

their outflow tract competely allowing for back flow producing a

low-intensity diastolic murmur, but never more than 2/6 (suspect

valvular failure)

- Caged ball and tissue valves cause no diastolic murmur since they

completely occlude their outflow tract in the closed position (any

degree of diastolic is pathologic unless proven otherwise.

slide25
- Mitral prosthetic valves

- A low-grade systolic murmur maybe heard with Caged ball

valves due to the turbulent flow caused by the cage projecting

into the left ventricle

- Any holosystolic murmur greater than 2/6 is

pathologic in a patient with an artificial mitral valve.

-Short diastolic murmurs

- best heard at the apex with the patient in the left

lateral decubitus position

-may be heard with bioprostheses and,

the St. Jude bileaflet valve

slide26
Acute valvular failure results in cardiogenic shock and severe hypotension:
    • Evidence of poor tissue perfusion : diminished peripheral pulses, cool or mottled extremities, confusion or unresponsiveness, and decreased urine output.
    • A hyperdynamicprecordium and right ventricular impulse is present in 50% of patients
    • Absence of a normal valve closure sound or presence of an abnormal regurgitant murmur
  • Subacutevalvular failure may present with signs of gradually worsening left-sided congestive heart failure.
    • Rales and jugular venous distention
    • A new regurgitant murmur
    • Absence of normal closing sounds.
    • A new or worsening hemolytic anemia (may be the only presention)
slide27
PVE (often obscure)
    • Fever occurs in 97% of patients
    • A new or changing murmur is present in 56% of patients

.produced by valvular dehiscence, stenosis, or perforation

. May not occur early in the course of the illness & its absence does not exclude

the diagnosis

    • Classic signs for native valve endocarditis, including petechiae, Roth spots, Osler nodes, and Janeway lesions are often absent
    • Splenomegaly present in only 26% of early PVE cases and in 44% of late PVE cases.
    • PVE may present as congestive heart failure, septic shock, or primary valvular failure.
    • Systemic emboli may be the presenting symptom in 7-33% of cases of PVE(more common with fungal etiologies)
  • Thromboembolic complications: signs related to the site of embolization.

. Stroke ,MI, sudden death, or visceral or peripheral embolization

. Systemic embolization should alert the physician to suspect valve thrombosis/ PVE

  • Anticoagulant-related hemorrhage: Signs depend on the site of hemorrhage
causes
Causes
  • Prosthetic valve endocarditis (PVE) has been divided into 2 subcategories in accordance with differences in clinical features, microbial patterns, and mortality:
    • Early PVE occuring within 60 days of valve insertion

. is usually the result of perioperative contamination

. Causative organisms include

- Staphylococcus epidermidis (25-30%)

-Staphylococcus aureus (15-20%)

- gram-negative aerobes (20%)

- fungi (10-12%)

- streptococci (5-10%)

- diphtheroids (8-10%).

slide29
Late PVE appearing after 60 days of valve insertion

. is usually the result of transient bacteremia from

dental or genitourinary sources, GI manipulation,

or intravenous drug abuse

. The causative organisms

-are similar to those causing native valve

endocarditis

-Include Streptococcus viridans (25-30%)

S epidermidis (23-38%)

S aureus (10-12%)

gram-negative bacilli (10-12%)

group D streptococci (10-12%)

fungi (5-8%)

and diphtheroids (4-5%).

slide30
*Multiple negative blood culture maybe seen with infections by

- The (HACEK) group:

Haemophilusaphrophilus

Actinobacillusactinomycetemcomitans

Cardiobacteriumhominis

Eikenellacorrodens

and Kingellakingae

- Serratia and Rickettsia species

- Aspergillus

- Histoplasma

- and Candida species.

**Brucella :rare

differential diagnoses
Differential Diagnoses
  • Chronic anemia
  • Peripheral vascular disease
  • Aortic regurgitation/ stenosis
  • Mitral regurgitation/ stenosis
  • Pulmonary embolism
  • Cardiogenic shock / septic shock
  • CHF & Pulmonary edema
  • Endocarditis
  • stroke Hemorrhagic/ ischemic
  • Myocardial infarction
imaging studies
Imaging Studies
  • An overpenetratedanteroposterior chest radiograph could aid in delineating the valvular morphology and whether or not the valve and occluder are intact. In more stable patients, a lateral chest film helps identify the valve position and type.
  • Radiographic appearance of the more commonly seen valves
    • Starr-Edwards caged ball valve
      • Radiopaque base ring
      • Radiopaque cage
      • Three struts for the aortic valve; 4 struts for the mitral or tricuspid valve
      • Silastic ball impregnated with barium that is mildly radiopaque (but not in all models)
    • Bjork-Shiley tilting disc valve (discontinued, but many patients still have these valves implanted)
      • Base ring and struts are radiopaque.
      • Two U-shaped struts project into base ring.
      • Edge of occluder disc is also radiopaque.
    • Medtronic-Hall tilting disc valve
      • Radiopaque base ring
      • Radiopaque struts that project into base ring: 3 small ones and 1 large hook-shaped one
      • Occluder disc that is mildly opaque but often cannot be seen
slide34
Alliance Monostrut valve
    • Occluder has a radiopaque rim.
    • The base ring and two struts are radiopaque.
  • St. Jude medical bileaflet valve
    • Mildly radiopaque leaflets are best seen when viewed on end. Seen as radiopaque lines when the leaflets are fully open.
    • Base ring is not visualized on most models.
    • The valve may not be visualized on some radiographs.
  • CarboMedicsbileaflet valves: Valve housing and leaflets are radiopaque and easily visible.
  • Carpentier-Edwards porcine valve: The tall serpiginous wire support is the only visualized portion.
  • Hancock porcine valve
    • The radiopaque base ring is the only visible part in some models.
    • Other models have radiopaque stent markers with or without a visible base ring.
  • Ionescu-Shiley bovine pericardial valve: Base ring and wide fenestrated stents are one piece.
laboratory studies
Laboratory Studies
  • Complete blood count
    • Microscopic evidence of hemolysis should be present.
    • A sudden increase in hemolysis may signal a perivalvular leak.6
    • A hematocrit lower than 34% is present in 74% of patients and is the most common hematologic finding.
    • A WBC count lower than 12,000 is present in as many as 54% of patients with PVE.
  • Urinalysis: Hematuria is present in 57% of patients with PVE.
  • Blood cultures
    • Culture results are positive in multiple samples in 97% of patients with PVE.
    • Blood cultures should be held for 3 weeks.

*Multiple blood cultures should be taken.

slide36
Prothrombin time (PT)/international normalized ratio (INR) general guideline( but therapy must be individualized)
    • Bioprosthetic valves:

INR 2-3 for 3 months following implantation;

may then be discontinued unless otherwise indicated e.g. AF or

development of prosthetic valve thrombosis.

    • Mechanical valves:

. INR 2.5-3.5

. patients with AF and those with valves in the mitral

position should be kept at the higher end of this range

. Patients with bileaflet valves may be kept at the lower end

of this range

    • Subtherapeutic values should raise the suspicion of valve thrombosis or systemic embolization.
slide37
Echocardiography
    • Acoustic shadowing originating from the components of the prosthetic valve especially the mitral can severely limit the image interpretation
    • Two-dimensional and Doppler echocardiography may demonstrate :

perivalvular leaks

vegetations

inadequate valve/occluder movement.

    • Two-dimensional echocardiography and Doppler echocardiography can detect the presence of acute valvular regurgitation and grade the severity.
    • Transesophageal echocardiography is the imaging study of choice in patients with a suspected prosthetic valve complication.
    • A normal transthoracic echocardiogram does not rule out a pathologic process.
  • Cinefluorography may detect impaired occluder movement but often cannot readily determine the etiology.
other tests
Other Tests
  • Electrocardiography
    • An atrioventricular (AV) block may indicate the presence of a myocardial abscess.
    • A fever and new AV block is considered PVE until proven otherwise.
    • Atrial fibrillation is common in mitral valve replacement and may cause hemodynamic compromise.
emergency department care
Emergency Department Care
  • In patients with acute valvular failure, diagnostic studies must be performed simultaneously with resuscitative efforts.
  • Primary valve failure: due to breakage or abrupt tearing of the components usually present with acute hemodynamic deterioration and needs immediate valve replacement, meanwhile:
    • Reduce the impedance to forward flow and improve peripheral perfusion via afterload reduction and inotropic support .

-If the mean arterial pressure is higher than 70 mm Hg: sodium

nitroprusside

- If the mean arterial pressure is lower than 70 mm Hg: dobutamine

alone or in combination with inamrinone

    • Avoid inotropic agents with vasoconstricting properties.
    • In cases of acute mitral regurgitation and surgical facilities are not immediately available: Intra-aortic balloon counterpulsation
    • Intra-aortic balloon counterpulsation is relatively contraindicated in the presence of an incompetent aortic valve.
slide41
Prosthetic valve endocarditis
    • Administer intravenous antibiotics

. after 2 sets of blood cultures are drawn

. Vancomycin and gentamicin may be used empirically pending blood

cultures and determination of methicillin resistance

    • Consider anticoagulation , the incidence of systemic embolization is as high as 40%.
    • Consider emergency surgery in

. patients with moderate-to-severe heart failure

. patients with an unstable prosthesis noted on echocardiography or

fluoroscopy

  • Thromboembolic complications
    • Patients presenting with embolization need to be anticoagulated if they are not already taking anticoagulants or have a subtherapeutic INR.
    • Assessment of valve function is needed.
slide42
Prosthetic valve thrombosis
    • Surgery

. the mainstay of treatment

. associated with a high mortality rate: 20-40% in

NYHA class IV

    • Thrombolytic therapy may be used to treat select patients with thrombosed prosthetic valves.
    • Patients with right/left -sided prosthetic valve thrombosis and NYHA class III and IV, pulmonary edema, or hypotension may benefit from thrombolysis due to the higher operative mortality.
slide43
Contraindications to thrombolysis of left-sided prosthetic valve thrombosis :

. presence of a large left atrial thrombus

. ischemic CVA less than 6 weeks ago

. <4 d postoperative

  • Thrombolytic therapy should always be done in conjunction with cardiovascular surgical consultation.
  • Thrombolysis is emerging as the treatment of choice in obstructing prosthetic valvular thrombosis.
  • The chance of a successful thrombolysis is inversely related to:

. the size of the thrombus

. the amount of time that has elapsed since the onset of

symptoms

slide44
Anticoagulant-related hemorrhage
    • Major anticoagulant-related hemorrhage require reversal of their anticoagulation with fresh frozen plasma and vitamin K.
    • The time off anticoagulants should be as short as possible to avoid valve thrombosis.
    • Use of recombinant factor VIIa or prothrombin complex concentrate should not be used to reverse excessive anticoagulation in patients with prosthetic heart valves
medication
Medication
  • Antibiotics
  • Vasodilators
  • Inotropic agents
  • Anticoagulants
vasodilators
Vasodilators
  • Role:

- in acute mitral or aortic valve failure ,a

significant portion of the cardiac output is

regurgitated through the incompetent

valve

- catecholamines worsen this effect by

increasing peripheral vascular resistance

- Vasodilators reduce SVR allowing forward flow,

improving cardiac output.

slide47
Nitroprusside (Nitropress) :
  • Action:

. Produces vasodilation

. increases inotropic activity

. Causes peripheral vasodilation by direct action on venous and arteriolar smooth

muscle, reducing peripheral resistance.

. At higher dosages, may exacerbate myocardial ischemia by increasing heart rate.

  • Dosing

Adult

. Begin infusion at 0.3-0.5 mcg/kg/min IV

. increase in increments of 0.5 mcg/kg/min, titrating to desired hemodynamic

effects

. average dose is 1-6 mcg/kg/min IV *Infusion rates >10 mcg/kg/min IV may lead to cyanide toxicity

Pediatric: as in adults

  • Interactions : additive effect when administered with other hypotensive agents
slide48
Contraindications

.Documented hypersensitivity

.subaorticstenosis

. atrial fibrillation or flutter

  • Pregnancy

Fetal risk : not established in humans

  • Precautions

increased intracranial pressure

hepatic failure

severe renal impairmen

hypothyroidism

sodium nitroprusside has the ability to lower blood pressure and thus

should be used only in patients with mean arterial pressures >70 mm Hg

* in renal or hepatic insufficiency, nitroprusside levels may increase

leading to cyanide toxicity

inotropic agents
Inotropic agents
  • Action: increase cardiac output. Avoid vasoconstricting agents to avoid increases in valvular regurgitation.
  • Dobutamine (Dobutrex)

-A Synthetic direct-acting sympathomimetic ,catecholamine

and beta-receptor agonist

- Produces vasodilation and increases inotropic state.

- At higher dosages:

. may increase heart rate, excerbating myocardial

ischemia

-Does not significantly increase myocardial oxygen demands:

its major advantage over other direct-acting catecholamines.

slide50
-Dosing

Adults

-Start at low rate (1 mcg/kg/min IV infusion)

-titrated at intervals of few minutes guided by:

patient's response including : systemic blood pressure

urine flow

frequency of ectopic activity

heart rate

and if possible: measurement of cardiac output

central venous pressure

and/or pulmonary capillary wedge

pressure - usual range :2-20 mcg/kg/min IV dictated by clinical response

Pediatrics: as in adults

slide51
-Interactions:

Beta-adrenergic blockers antagonize effects of dobutamine;

general anesthetics may increase toxicity

-Contraindications

Documented hypersensitivity

subaorticstenosis

atrial fibrillation or flutter

- Pregnancy: Fetal risk not confirmed

-Precautions

Increased intracranial pressure

severe renal / hepatic impairment: increased evels may cause cyanide toxicity

hypothyroidism

following MI

correct hypovolemic state before using this drug

slide52
Inamrinone (Inocor): Formerly amrinone

A Phosphodiesterase inhibitor with positive inotropic and

vasodilator activity

More likely to cause tachycardia than dobutamine

exacerbating myocardial ischemia.

-Dosing

Adult

0.75 mg/kg IV bolus slowly over 2-3 min

maintenance infusion is 5-10 mcg/kg/min IV

do not to exceed 10 mg/kg dose adjusted according to patient's response

Pediatric Not established; may administer as in adults

slide53
-Interactions

Diuretics may cause significant hypovolemia and

a decrease in filling pressure

additive effects to cardiac glycosides

  • Contraindications:Documented hypersensitivity
  • Pregnancy: Fetal risk not established
  • Precautions

liver toxicity

correct hypokalemic states before inamrinone

anticoagulants
Anticoagulants
  • Indications:

-bioprosthetic valves need anticoagulants for 3 months

- mechanical valves and in patients with atrial fibrillation need lifelong

anticoagulation

- Any patients presenting with thromboembolic complications must be

promptly anticoagulated if they do not have a therapeutic INR of 2.5-3.5.Heparin: - Augments activity of antithrombin III and prevents conversion of fibrinogen to fibrin

- Does not actively lyse but is able to inhibit further thrombogenesis

- Prevents reaccumulation of clot after spontaneous fibrinolysis.

  • Dosing

- Adult : Initial dose: 40-170 U/kg IV Maintenance infusion: 18 U/kg/h IV Alternatively:50 U/kg/h IV initially, followed by continuous infusion of

15-25U/kg/h and increase dose by 5 U/kg/h q4h prn using aPTT results

-Pediatric : Initial dose: 50 U/kg IV Maintenance infusion: 15-25 U/kg/h IV Increase dose by 2-4 U/kg/h IV q6-8h prn using aPTT results

slide55
Interactions : Effect decreased by: Digoxin

nicotine

tetracycline

antihistamines

Toxicity may be increased by: NSAIDs

aspirin

dextran

dipyridamole

hydroxychloroquine

  • Contraindications: Documented hypersensitivity

subacute bacterial endocarditis

active bleeding

history of heparin-induced thrombocytopenia

  • Pregnancy : safety not established
  • Precautions : In neonates: preservative-free heparin is recommended to avoid

possible toxicity (gasping syndrome) by benzyl alcohol

caution in severe hypotension and shock

antibiotics
Antibiotics

Amoxicillin:

Derivative of ampicillin

Active against certain gram-positive and gram-negative

organisms

Superior bioavailability and stability to gastric acid

broader spectrum of activity than penicillin.

less active against Streptococcus pneumococcus

Penicillin-resistant strains also resistant to amoxicillin less so

at higher doses

More effective against gram-negative organisms (eg, N

meningitidis, H influenzae)

bactericidal : interferes with synthesis of cell wall

mucopeptides during active multiplication

DOC for prophylaxis in nonallergic patients undergoing

dental, oral, or respiratory tract procedures.

slide57
. Dosing:

Adult: 2 g PO 1 h before procedure

Alternatively, 3 g PO 1 h before procedure, followed by

1.5 g PO 6 h after initial dose

Pediatric : 50 mg/kg PO 1 h before procedure

. Interactions: May reduce efficacy of oral contraceptives

. Contraindications : Documented hypersensitivity

. Pregnancy : safety unestablished

. Precautions: Renal impairment

slide58
Ampicillin :

- Broad-spectrum bactericidal

- Interferes with bacterial cell wall synthesis during active replication

- Alternative to amoxicillin when unable to take medication orally. - prophylaxis in patients undergoing dental, oral, or respiratory tract

procedures.

- Coadministered with gentamicin for prophylaxis in GI or genitourinary

procedures.

  • Dosing

Adult : 2 g IV/IM 30 min prior to procedure High-risk patients: 2 g ampicillin IV/IM followed 6 h later by 1 g IV/IM

Pediatric : 50 mg/kg IV/IM 30 min prior to procedure High-risk patients: 50 mg/kg IV/IM ampicillin

followed 6 h later by 25 mg/kg IV/IM

slide59
Interactions

-ampicillin level elevated by Probenecid and disulfiram

-allopurinol decreases ampicillin effects and has additive

effects on ampicillin rash

-may decrease effects of oral contraceptives

  • Contraindications : Documented hypersensitivity
  • Pregnancy: safety not established
  • Precautions :Adjust dose in renal failure

evaluate rash and differentiate from

hypersensitivity reaction

slide60
Azithromycin :

-Acts by: binding to 50S ribosomal subunit of susceptible

microorganisms and blocks dissociation of peptidyltRNA

from ribosomes, causing RNA-dependent protein synthesis

to arrest.

-Nucleic acid synthesis is not affected.

-Concentrates in phagocytes and fibroblasts contributing to drug

distribution to inflamed tissues

-Treats mild-to-moderate microbial infections. - tissue concentrations are higher than Plasma concentrations giving it

value in treating intracellular organisms.

-Has a long tissue half-life. -Used in penicillin-allergic patients undergoing dental, esophageal, and

upper respiratory procedures.

slide61
. Dosing :

Adult : 500 mg PO 1 h before procedure

Pediatric : 15 mg/kg PO 1 h before procedure; not to exceed 500 mg

.Interactions : May increase toxicity of : theophylline

warfarin

digoxin

effects are reduced with coadministration of aluminum and/or magnesium

antacids

nephrotoxicity and neurotoxicity may occur when coadministered with

cyclosporine

.Contraindications : Documented hypersensitivity

hepatic impairment: do not administer with pimozide

.Pregnancy : not established

.Precautions : Site reactions can occur with IV route

bacterial or fungal overgrowth may result from prolonged antibiotic use

may increase hepatic enzymes and cholestatic jaundice

prolonged QT intervals

pneumonia

hospitalized geriatric or debilitated patients

slide62
Cefazolin:

-First-generation semisynthetic cephalosporin that

-arrests bacterial cell wall synthesis and inhibits bacterial replication by

binding to 1 or more penicillin-binding proteins

- Poor capacity to cross blood-brain barrier

-Primarily active against skin flora, including S aureus

-typically used alone for skin and skin-structure coverage

slide63
.Dosing:

Adult: 1 g IV/IM 30-60 min before procedure

Pediatric: 50 mg/kg IV/IM 30-60 min before procedure

Do not to exceed 1 g/dose

.Interactions: Probenecid prolongs effect of cefazolin

coadministration with aminoglycosides may increase renal

toxicity and yield false-positive urine-dip test results for

glucose

.Contraindications : Documented hypersensitivity

.Pregnancy :safety not established

.Precautions: high doses may cause CNS toxicity ,Adjust dose in severe

renal insufficiency

prolonged use or repeated therapy may yield superinfections

and promotion of nonsusceptible

slide64
Ceftriaxone:

-Third-generation Bactericidal cephalosporin

- Acts by inhibiting cell wall synthesis

-broad-spectrum gram-negative activity

-lower efficacy against gram-positive organisms

-Highly stable in presence of beta-lactamases, both penicillinase and

cephalosporinase, of gram-negative and gram-positive bacteria.

- 33-67% excreted unchanged in urine,

remainder secreted in bile and then feces as microbiologically inactive

compounds.

- Reversibly binds to human plasma proteins

slide65
Dosing

Adult: 1 g IV/IM 30-60 min before procedure

Pediatric : 50 mg/kg IV/IM 30-60 min before procedure; not to exceed 1 g

  • Interactions:

- Probenecid may increase ceftriaxone levels

- coadministration with ethacrynic acid, furosemide, and aminoglycosides may increase

nephrotoxicity

- simultaneous administration with IV calcium-containing solutions may cause

precipitation (thoroughly flush infusion lines between ceftriaxone and calcium)

  • Contraindications : Documented hypersensitivity

hyperbilirubinemic neonates

  • Pregnancy : safety not established
  • Precautions : -Adjust dose in severe renal insufficiency (high doses may cause CNS toxicity)

- superinfections and promotion of nonsusceptible organisms may occur with

- prolonged use or repeated therapy

- caution in breastfeeding women

- may displace bilirubin from albumin-binding sites, increasing the risk of

kernicterus

- caution with gallbladder, biliary tract, liver, or pancreatic disease

- caution in patients with history of colitis or penicillin hypersensitivity

slide66
Cephalexin:

- First-generation Bactericidal cephalosporin that inhibits bacterial

replication by inhibiting bacterial cell wall synthesis

(effective against rapidly growing organisms forming cell walls)-Resistance occurs by alteration of penicillin-binding proteins.

-Effective against streptococcal & staphylococci, including

penicillinase-producing staphylococci.

slide67
Dosing

Adult : 2 g PO 1 h before procedure

Pediatric : 50 mg/kg PO 1 h before procedure; not to exceed 2 g/dose

  • Interactions:

Coadministration with aminoglycosides increases nephrotoxic

potential

  • Contraindications: Documented hypersensitivity
  • Pregnancy : safety not established
  • Precautions: Adjust dose in severe renal insufficiency

(high doses may cause CNS toxicity)

prolonged use or repeated therapy may yield

superinfections

and promotion of nonsusceptible organisms

slide68
Clarithromycin:

-Semisyntheticmacrolide

-reversibly binds to P site of 50S ribosomal

subunit of susceptible organisms

-may inhibit RNA-dependent protein

synthesis by stimulating dissociation of peptidyl

tRNA from ribosomes, causing bacterial growth

inhibition. -Used in penicillin-allergic patients undergoing

dental, esophageal, and upper respiratory

procedures.

slide69
Dosing

Adult : 500 mg PO 1 h before procedure

Pediatric : 15 mg/kg PO 1 h before procedure; not to exceed 500 mg/dose

  • Interactions: Toxicity increases with fluconazole

and pimozide

effects decrease and GI adverse effects may increase with rifabutin

or rifampin

may increase toxicity of anticoagulants

cyclosporine

tacrolimus

digoxin

carbamazepine

ergot alkaloids

triazolam

HMG-CoAreductase inhibitors

slide70
Plasma levels of certain benzodiazepines may increase, prolonging

CNS depression

arrhythmias and increases in QTc intervals occur with disopyramide

coadministration with omeprazole may increase plasma levels of

both agents

decreases metabolism of repaglinide, thus increasing serum levels

and effects

  • Contraindications : Documented hypersensitivity

coadministration with pimozide

  • Pregnancy: safety not established
  • Precautions: Coadministration with ranitidine or bismuth citrate is not

recommended with CrCl <25 mL/min

give half dose or increase dosing interval if CrCl <30 mL/min

diarrhea may be a sign of pseudomembranous colitis

superinfections may occur with prolonged or repeated antibiotic

therapies

slide71
Clindamycin: Semisynthetic antibiotic produced by 7(S)-chloro-substitution

of 7(R)-hydroxyl group of parent compound lincomycin

Inhibits bacterial growth, possibly by blocking dissociation of

peptidyltRNA from ribosomes, causing RNA-dependent

protein synthesis to arrest

Widely distributed in the body

Does not penetrate the CNS

Protein bound

Excreted by the liver and kidneys

Used in penicillin-allergic patients undergoing dental, oral, or

respiratory tract procedures

Useful for treatment against streptococcal and most

staphylococcal infections

slide72
Dosing

Adult : 600 mg PO/IV 1 h prior to the procedure;

150 mg PO/IV 6 h after first dose

Pediatric : 20 mg/kg PO 1 h

or 20 mg/kg IV 30 min before procedure

Do not to exceed 600 mg/dose

  • Interactions : Increases duration of neuromuscular blockade induced by tubocurarine and pancuronium

erythromycin may antagonize effects of clindamycin

antidiarrheals may delay absorption of clindamycin

  • Contraindications: Documented hypersensitivity

regional enteritis

hepatic impairment

ulcerative colitis

antibiotic-associated colitis

  • Pregnancy : safety not established
  • Precautions: Adjust dose in severe hepatic dysfunction

associated with severe and possibly fatal colitis

slide73
Gentamicin:

- Aminoglycoside antibiotic for gram-negative bacteria including

Pseudomonas species

- Synergistic with beta-lactamase against enterococci

- Interferes with bacterial protein synthesis by binding to 30S

and 50S ribosomal subunits. - Dosing regimens are numerous and are adjusted based on:

CrCl

changes in volume of distribution

body space into which the agent needs to distribute

- may be given IV/IM

- Each regimen must be followed by at least trough level drawn

on third or fourth dose, 0.5 h before dosing;

may draw peak level 0.5 h after 30-min infusion.

slide74
Dosing

Adult : -Penicillin-susceptible streptococcal endocarditis:

1 mg/kg IV q8h for 2 wk; used in combination with

ceftriaxone -Enterococcal: 1 mg/kg IV q8h for 4 wk; used in combination

with ampicillin -MSSA: 1 mg/kg IV q8h for 3-5 d; used in combination with

nafcillinPediatric : as in adults

  • Interactions

-Coadministration with other aminoglycosides, cephalosporins, penicillins,

and amphotericin B may increase nephrotoxicity

-aminoglycosides enhance effects of neuromuscular blocking agents

prolonged respiratory depression may occur

-coadministration with loop diuretics may increase auditory toxicity with

possible irreversible hearing loss of varying degrees may occur

(monitor regularly)

slide75
Contraindications: Documented hypersensitivity;

non – dialysis-dependent renal insufficiency

  • Pregnancy : safety not established
  • Precautions :

- Narrow therapeutic index (not intended for long-term therapy)

- caution in renal failure (not on dialysis)

- adjust dose in renal impairment

- myasthenia gravis

- hypocalcemia

-conditions that depress neuromuscular transmission

slide76
Vancomycin:

Potent antibiotic directed against gram-positive organisms

and Enterococcus species

treatment of septicemia and skin structure infections

Indicated for patients who:

-cannot receive or have failed to respond to penicillins

and cephalosporins

-have infections with resistant staphylococci

adjust dose in patients with renal impairment.

slide77
Dosing

Adult : Dental, oral, upper respiratory tract, and genitourinary procedures:

1 g IV infused over 1 h, 1 h prior to procedure

Pediatric: Dental, oral, upper respiratory tract, and genitourinary procedures:

20 mg/kg IV over 1 h, 1 h prior to procedure

  • Interactions: Erythema, histaminelike flushing, and anaphylactic reactions may occur when

administered with anesthetic agents

when taken concurrently with aminoglycosides, risk of nephrotoxicity may

increase above that with aminoglycosidemonotherapy

effects in neuromuscular blockade may be enhanced when coadministered with

nondepolarizing muscle relaxants

  • Contraindications: Documented hypersensitivity
  • Pregnancy: safety not established
  • Precautions: renal failure

neutropenia

red man syndrome is caused by too rapid IV infusion (dose given over a few

min) but rarely happens when dose is given as 2-h administration or as

PO or IP administration; red man syndrome is not an allergic reaction

transfer
Transfer

The mortality is related directly to the delay of surgical correction.

prophylaxis
Prophylaxis
  • antibiotic prophylaxis :
    • Dental and oral procedures
    • Respiratory procedures, particularly those which involve disruption of the respiratory mucosal surface, or when a known infection is present
      • If a known infection caused by Staphylococcus aureus is present, prophylaxis with an antistaphylococcal penicillin, cephalosporin, or vancomycin should be given.
      • In cases of known or suspected methicillin-resistant Staphylococcus aureus, prophylaxis with vancomycin should be given.
    • Sclerotherapy of bleeding esophageal varices
    • Routine prophylaxis for gastrointestinal or genitourinary procedures is no longer recommended, unless in the presence of a known infection.
      • Urethral catheterization in the presence of a suspected urinary tract infection
      • Vaginal delivery in the presence of infection
    • Incision and drainage of infected tissues
slide80
For dental, oral, or upper respiratory tract procedures, use amoxicillin 2 g PO 30-60 minutes before the procedure.
    • If unable to take PO medication, use ampicillin 2 g IM/IV OR cefazolin 1 g IM/IV, OR ceftriaxone 1 g IM/IV 30-60 minutes before the procedure.
    • For penicillin-allergic patients, use clindamycin 600 mg PO/IM/IV OR azithromycin 500 mg PO OR clarithromycin 500 mg PO OR cephalexin 2 g PO 30-60 minutes before the procedure.
    • These are all single-dose regimens.
    • Do not use cephalexin in patients with a documented significant allergy to penicillin unless there is documentation that the patient can tolerate cephalosporins.
complications81
Complications
  • Glomerulonephritis
  • mycotic aneurysms
  • and metastatic abscesses
special concerns
Special Concerns
  • Pregnancy

Some debate exists:

    • Warfarin increases the chance of spontaneous abortion and stillbirths and is associated with teratogenicity from 6-12 weeks' gestation.
    • Current recommendations are to use heparin from 6-12 weeks and from 38-40 weeks' gestation. Warfarin may be used for the remainder of pregnancy.
    • The American College of Obstetrics and Gynecology have recommended that low molecular weight heparin not be used in pregnancy.
slide83
Heart Disease has been around as long as we have.

Medications, surgery, PCI, Stents….. All cure the heart that we can see and physically touch.

The essence of our heart, the one with the soul that is inconceivable to our physical science, has yet to be tackled.

Love,hate, jealousy,lonlinless,and all the lost souls need mending too…

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