Tricuspid Valve Disease Endocarditis Department of Thoracic

Tricuspid Valve Disease Endocarditis Department of Thoracic & Cardiovascular Surgery Seoul National University Hospital &

Tricuspid Valve ØAnatomy • Normal tricuspid valve area ; 10. 5 cm 2 • Normal valve diameter ; 40 - 45 mm • No actual tricuspid annulus ; attached to AV junction • Tricuspid valve ring is related to the base of AV, membranous septum, CFB, RCA, CS, bundle of His

Tricuspid Valve ØAnatomy • View of tricuspid valve and surgical importance

Tricuspid Regurgitation ØPathophysiology • The most common presentation of tricuspid regurgitation is secondary, functional rather than organic from mostly MS, MR or in isolated aortic valve disease • As pulmonary hypertension develops leading to right ventricular dilation, tricuspid annulus will dilate • The circumference of annulus lengthens primarily along the attachments of the anterior and posterior leaflets. • The septal leaflets is fixed between the fibrous trigones, preventing lengthening. • As the annular & ventricular dilation progresses, chordal papillary muscle complex becomes functionally shortened • This combination prevents leaflet apposition, resulting in valvular incompetence

Tricuspid Valve Disease ØEtiology • • • Mostly secondary (functional) to valve pathology Eisenmenger’s syndrome Primary pulmonary hypertension Marfan syndrome and other myxomatous disease Blunt or penetrating chest trauma Dilated cardiomyopathy in the late stages Infectious endocarditis Carcinoid syndrome Rheumatic disease of the tricuspid valve is always associated with mitral valve

Functional Tricuspid Regurgitation ØProcess of annular dilatation • Pathological process of tricuspid annular dilatation. Arrows designate the intercommissural distance that increases with dilatation and that is measured intraoperatively.

Functional Tricuspid Regurgitation ØPrerequisite • For the tricuspid valve to leak, the tricuspid annulus and hence the right ventricle has to be dilated • In addition to tricuspid dilatation, three important factors determine whether TR occurs: the preload, afterload, and right ventricular function. • This may explain why TR is difficult to accurately assess because these factors can interfere with regard to the severity of TR under different conditions.

Functional Tricuspid Regurgitation 1. Controversies 2. Early investigators advocated a conservative approach, arguing that functional TR, often secondary to pulmonary hypertension and concomitant mitral valve disease, should spontaneously improve after mitral valve repair 3. Subsequent studies, however, have demonstrated that TR does not necessarily regress after repair of left-sided valve lesions 4. Uncorrected TR increases both postoperative morbidity and mortality and is associated with poor long-term results with medical management alone

Tricuspid Regurgitation ØClinical presentation • Fatigue & weakness related to reduction of cardiac output • Right heart failure lead to ascites, venous engorgement, hepatospenomegaly, pulsatile liver, pleural effusions & peripheral edema • In late stage, cachexia, cyanosis, jaundice & AF is common

Tricuspid Regurgitation ØSigns

Tricuspid Stenosis ØClinical presentation • Most commonly rheumatic, rare isolated stenosis • Fatigue & malaise related to reduction of CO • As the right atrial pressure increases, venous congestion leads to distention of jugular veins, hepatomegaly, ascites, pleural effusion, & peripheral edema • Anatomic features are similar to mitral stenosis with fusion and shortening of chordae & leaflet thickening • The right atrial wall thickens and chamber dilates

Tricuspid Valve Disease ØIndications for surgery • Repair of tricuspid stenosis is indicated for class III-IV symptoms, including hepatic congestion, ascites, and peripheral edema that are refractory to medical treatment • Repair of tricuspid regurgitation is indicated for severe symptoms or when moderate-tosevere functional TR is present at left-sided valve surgery. Repair is especially important if PVR is elevated.

Tricuspid Valve Repair ØBicuspidalization Plicating the annulus along the posterior leaflet Flexible ring placed, ring can be above coronary sinus

Tricuspid Regurgitation ØTricuspid valve annuloplasty

Tricuspid Regurgitation ØTricuspid valve annuloplasty • Modified De. Vega annuloplasty

Tricuspid Regurgitation ØTricuspid valve annuloplasty • Suture bicuspidization is performed by placement of a 2 -0 pledgetsupported Ethibond mattress suture from the anteroposterior to the posteroseptal commissures along the posterior annulus.

Tricuspid Regurgitation ØTricuspid valve annuloplasty • Carpentier-Edwards ring annuloplasty

Tricuspid Valve Annuloplasty ØCosgrove-Edwards System Annular sutures extend from the posteroseptal to the anteroseptal commissure and are placed through the polyester velour band of the annuloplasty system

Tricuspid Valve Annuloplasty ØCosgrove-Edwards System A measured plication of the annulus adjacent to the anterior & posterior leaflets is achieved and the conduction system is not jeopardized.

Traumatic Tricuspid Regurgitation ØClover technique Surgical steps of the clover technique

Tricuspid Regurgitation ØTricuspid valvuloplasty • Partial Commissure Closure & Leaflet Cleft Repair

Tricuspid Regurgitation ØPartial annuloplasty

Tricuspid Valvuloplasty ØEdge-to-edge valve plasty A U-shaped 5 -0 polypropylene stitch reinforced with small pericardial pledgets passes through the middle point of the free edges of the tricuspid leaflets. The anterior leaflet is anchored to the facing edges of posterior and septal leaflets to create a triple orifice tricuspid valve.

Tricuspid Valve Disease ØOperative management • Results be interpreted with early & late results of mitral & double valve procedures • Indications ; NHYA functional class III & IV • TV repair is preferable to valve replacement - Due to unfavorable complications of TVR (TE, thrombosis, anticoagulation problems)

Tricuspid Valve Annuloplasty ØRisk factors for late failure • • Greater preoperative TR grade Preoperative TR without concomitant MR Higher postoperative PASP NYHA, preoperative PASP, preoperative RV dysfunction, recurrent MR were not significant risk factors.

Tricuspid Regurgitation ØResults of operative treatment • Clinical and surgical management of tricuspid valve disease have evolved from conservative approaches, that is, spontaneous regression after correction of leftsided lesions, to a more interventionist care. • At present, it is well known that tricuspid regurgitation grades 3+ and 4+ that are not surgically corrected or that reappear after operation are prognostic factors of poor long-term outcome. • Dysfunction after tricuspid valve repair requiring reoperation was associated with a high hospital mortality

Tricuspid Valve Replacement ØProsthetic valve choice • The choice of prosthesis follows the algorithm similar to that used for valve replacement in other cardiac valve positions ( demonstrating equality ) • The patient’s age, anticoagulation considerations in women and social issues must be considered • Degenerative changes were less for bioprosthesis in the tricuspid position than in the mitral, however , thrombus and pannus formation were more frequent in the tricuspid position • Prostheses with more than 27 mm internal diameter do not have clinically significant gradient • Recommend a mechanical valve to young patients who do not have a contraindication to anticoagulation

Tricuspid Valve Replacement ØMitral homograft

Prosthetic Valve Endocarditis

Infective Endocarditis ØIntroduction • Rates of infective endocarditis in the general population have remained relatively constant and are estimated to be 5. 0 to 7. 0 cases per 100, 000 person-years in the United States • Contemporary causes of infective endocarditis include intravenous drug use (IVDU), use of prosthetic valves, sclerotic disease in the elderly, and nosocomial infection • Although high mortality remains associated with infective endocarditis, surgical treatment has greatly increased survival versus antibiotic treatment alone Early aggressive surgical intervention is often indicated to optimize surgical results

Infective Endocarditis ØDevelopment • Endocarditis usually develops in individauls with underlying structural cardiac defects who develop bacteremia with organisms likely to cause endocarditis • Surgical and dental procedures and instrumentations involving mucosal surfaces or contaminated tissue cause transient bacteremia that rarely persists for more than 15 minutes • Bacteremia may lodge on damaged or abnormal heart valves or on the endocardium or the endothelium near anatomic defects, resulting in bacterial endocarditis or endarteritis. • Although bacteremia is common following many invasive procedures, only certain bacteria commonly cause endocarditis

Active Infective Endocarditis ØIntroduction • Depending on how promptly the disease is diagnosed and appropriate antibiotics are started, on the virulence of the microorganism, and on whether the infected valve is native or prosthetic, surgery may become indispensable to save the patient’s life and eradicate the infection • Staphylococcus aureus was the most common microorganism, & less virulent streptococcus viridans, always respond to antibiotics alone is erroneous, because these bacteria can cause extensive damage to a heart valve and surrounding tissues if inadequately treated

Infective Endocarditis Modified Duke Criteria [Major criteria] Blood culture positive for IE (A) Typical microorganisms consistent with IE from 2 separate blood cultures: (1) Viridans streptococci, Streptococcus bovis, HACEK group, staphtlococcu aureus; or (2) Community-acquired enterococci, in the absence of a primary focus (B) Microorganisms consistent with IE from persistently positive blood cultures, defined as follows; (1) At least 2 positive cultures of blood samples drawn 12 h apart; or (2) All of 3 or a majority of ＞ 4 separate cultures of blood (with first and last sample drawn at least 1 h apart) (C) Single positive blood culture for Coxiella burnetii or antiphase I Ig. G antibody titer e ＞ 1: 800 Evidence of endocardial involvement (A) Echocaridiogram positive for IE (TEE recommended in patients with prosthetic valves, rated at least “possible IE” by clinical criteria, or complicated IE [paravalvular abscess]; TEE as first test in other patients), defined as follows; (1) Oscillating intracardiac mass on valve of an alternative anatomic explanation; or (2) Abscess; or (3) New vavular regurgitation (worsening or changing of pre-existing murmur not sufficient) [Minor criteria] (A) Predisposition: predisposing heart condition or injection drug use (B) Fever: temperature ＞ 38℃ (C) Vascular phenomena: major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages, and Janeway’s lesions (D) Immunologic phenomena: glomerulonephritis, Osle’s nodes, Roth’s spot, and rheumatoid factor (E) Microbiological evidence: positive blood culture but does not meet a major criterion as noted above or serological evdence of active infection with organism consistent with IE

Infective Endocarditis Modified Duke Criteria (Diagnosis) Definite infective endocarditis Pathologic criteria (1) Microorganisms demonstrated by culture or histologic examination of a vegetation, a vegetation that has embolized, or an intracardiac abscess specimen; or (2) Pathologic lesions; begetation or intracardiac abscess confirmed by histologic examination showing active endocarditis Clincal criteria (1) 2 major criteria; or (2) 1 major criterion and 3 minor criteria; or (3) 5 minor criteria Possible infective endocarditis (1) 1 major criterion and 1 minor criterion; or (2) 3 minor criteria Rejected (1) Firm alternate diagnosis explaning evidence of infective endocarditis; or (2) Resolution of infective endocarditis syndrome with antibiotic therapy for ＜ 4 days; or (3) No pathologic evidence of infective endocarditis at surgery or autopsy, with antibiotic therapy for ＜ 4 days; or (4) Dose not meet criteria for possible infective endocarditis, as above

Infective Endocarditis 1. Situations of high complication 2. Prosthetic cardiac valves 3. Left-sided infective endocarditis 4. Fungal infective endocarditis 5. Previous infective endocarditis 6. Prolonged clinical symptoms(>3 months) 7. Cyanotic congenital heart disease 8. Patients with systemic to pulmonary shunt 9. Poor clinical response to antimicrobial therapy

Infective Endocarditis ØNeed for surgical intervention v Vegetation • Persistent vegetation after systemic embolization • Increase in vegetation size after 4 weeks of antimicrobial therapy v Valvar dysfunction • Acute aortic or mitral regurgitation with ventricular dilatation • Heart failure unresponsive to medical therapy • Valve perforation or rupture v Perivalvar extension • Valvar dehiscence, rupture, or fistula • New heart block • Large abscess or extension of abscess despite appropriate antibiotic therapy

Prosthetic Valve Endocarditis Early Onset < 60 days Organism Staphylococci; Late > 60 days Streptococci; S. epidermidis, aureus. S. viridans, Gr D. Gr(-) organisms. Staphylococci. Fungi, Diphteroids Streptococci. * Risk of PVE: greatest at 5 wks following valve implantation

Prosthetic Valve Endocarditis ØPathology • Mechanical valve; Sewing ring, valve ring abscess, valve dehiscence, paravalvular leak • Tissue valve; Valve leaflets – greater success of antibiotic therapy

Infective Endocarditis ØParaannular ring abscess

Infective Endocarditis ØCauses of negative blood cultures • • • Rt-sided endocarditis Bacteria free-stage: very “chronic” SBE Uremia Poor bacteriologic sampling techniques Fastidious organisms needing special growth requirements • Prior administration of antibiotics • Nonbacterial causes of endocarditis

Native Valve Endocarditis ØSurgical indications • Presence of moderate-to-severe CHF • Persistent sepsis • Evidence of local extension producing annular or myocardial abscesses, conduction disturbance, or intracardiac fistula • Systemic embolization • Enlarging vegetations, threatened embolization

Infective Endocarditis 1. Surgical indications 2. Progressive heart failure 3. Significant heart failure: fails to improve 4. Major embolism, large vegetation ( >1 cm ) 5. Persistent bacteremia despite antibiotics 6. Fungal endocarditis 7. Patients with intravascular devices 8. Heart block 9. PV dehiscence or obstruction 10. Relapse

Infective Endocarditis 1. Tricuspid valve lesion 2. Increasing due to rising incidence of IV drug abuse 3. Surgical treatment is necessary when continued sepsis, moderate to severe HF, multiple pulmonary emboli(+) 4. Intensive medical Tx, valvectomy, valve replacement; aggressive counseling should be offered due to high incidence of recidivism

Endocarditis Prophylaxis ØCardiac conditions v High-risk category • Prosthetic cardiac valves, including bioprosthetic and homograft valves • Previous bacterial endocarditis • Complex cyanotic congenital heart disease • Surgical systemic pulmonary shunt or conduits v. Moderate-risk category • • Most other congenital cardiac malformations Acquired valvar dysfunction Hypertrophic cardiomyopathy Mitral valve prolapse with valve regurgitation and/or thickened leaflets

Endocarditis Prophylaxis ØCardiac conditions v. Negative-risk category (not greater than general) • Isolated secundum ASD • Surgical repair of ASD, VSD, or PDA ( without residua beyond 6 months ) • Previous coronary artery bypass graft surgery • Mitral valve prolapse without regurgitation • Physiologic, functional, or innocent heart murmur • Previous Kawasaki disease without valve dysfunction • Previous rheumatic fever without valvar dysfunction • Cardiac pacemakers( intravenous and epicardial ) and implanted defibrillators

Infective Endocarditis ØProphylactic regimens for procedures Situation Agent Srandard general Amoxicillin Regimen Adult; 2. 0 g orally 1 hour before procedure Child; 50 mg/kg orally Unable to oral intake Ampicillin Adult; 2. 0 g IM or IV, 30 m before procedures Child; 50 mg/kg 30 min. before Allergic to penicillin Clindamycin Adult; 600 mg, Child; 20 mg/kg 1 h before Cephalexin Adult; 2 g, Child; 50 mg/kg 1 h before Azithromycin Adult; 500 mg, Child; 15 mg/kg 1 h before or Clarithromycin Allergic & unable to Clindamycin or Oral intake Cefazolin Adult; 1 g, Child; 25 mg/kg 30 min. before procedure

Prosthetic Heart Valve Bioprosthetic Durability less Bleeding Cx. less Thromboemboism less Rheology Indication pregnant woman , old age Focus(BE) leaflet Mechanical more most pts sewing ring

Prosthetic Valve Endocarditis ØGross findings Tissue Valve Mechanical Valve

Redo Cardiac Valve Operation ØConsiderations • Careful preoperative study Chest lateral, Chest CT, Cardiac catheterization & angiography • Femoral dissection • Blood-saving procedure Autotransfusion, cell saver, aprotinin • Automatic implantable cardioverter defibrillator • Tissue valve(cusp tear) > mechanical valve(TE, SBE)

Infective Endocarditis ØManagement in septic shock • Nitric oxide has been implicated in these derangements. Exposure to endotoxin and cytokines can trigger a de novo synthesis of the inducible, calcium-dependent isoform of nitric oxide synthase. • Methylene blue inhibits this process by decreasing intracellular cyclic guanosine monophosphate concentrations through guanylate cyclase inhibition, thus blocking its vasodilator properties. • Methylene blue increases arterial pressure, systemic vascular resistance, and left ventricular stroke work but does not increase cardiac output, oxygen delivery, or oxygen consumption. 4

Infective Endocarditis ØIndications for surgery • Infective endocarditis have continued to evolve, but frequently include new severe valvular regurgitation, intractable heart failure, abscess formation, conduction abnormalities, recurrent embolic events, organism involved(fungal endocarditis), and presence of prosthetic material • While mortality has improved from 30% to 15% over the past two decades, it remains substantial

Infective Endocarditis 1. Echocardiographic diagnosis 2. Three echocardiographic findings are considered to be major criteria for the diagnosis of endocarditis: (1) presence of vegetations defined as mobile echodense masses implanted in a valve or mural endocardium; (2) presence of abscess; or (3) presence of a new dehiscence of a valvular prosthesis 3. With the development of TEE imaging, the noninvasive detection of vegetations has substantially improved

Infective Endocarditis ØCauses of operative deaths • Often multifactorial, but the main reasons were multiorgan failure, low cardiac output syndrome, intractable sepsis, coagulopathy , technical errors, stroke, pulmonary embolism, acute myocardial infarction, ruptured aortic root, valve dehiscence, retroperitoneal bleeding, and right ventricular failure • The predictors of operative mortality includes preoperative shock, prosthetic valve endocarditis, S aureus, and paravalvular abscess.

Infective Endocarditis ØResults of operative treatment • Surgery for endocarditis continues to be challenging & associated with high operative mortality & morbidity • Age, shock, prosthetic valve endocarditis, impaired ventricular function, and recurrent infections adversely affect long-term survival • Long-term survival is satisfactory, particularly for patients with native valve endocarditis & differences between native and prosthetic valve endocarditis are likely multifactorial and include higher operative mortality, more complex operations, and such patient variables as older age and worse ventricular function

Anticoagulation

Anticoagulation ØPolicy for prostheisis 1. Mechanical valves: All patients should be anticoagulated with coumadin. In addition, all patients would receive aspirin and persantine. Persantine is discontinued after 3 months. 2. Porcine or bovine valves: a) Aortic valve replacement: Aspirin and persantine starting on the 5 th postoperative day for 3 months. No anticoagulants per se need be given. b) Mitral and tricuspid valve replacement: ⅰ) Children with chronic atrial fibrillation or proven intra-atrial clot should be anticoagulated with coumadin, sapirin and persantine permanently. ⅱ) Patients in sinus rhythm should be anticoagulated with coumadin, aspirin, and persantine for a period of 3 months. All drugs to be discontinued at 3 months. c) Pulmonary valve replacement: No anticoagulants are required. ASA is recommended indefinitely. 3. Homograft pulmonary or aortic valve: No anticoagulants are required. ASA is recommended indefinitely.

Anticoagulation Ø Protocol for children British Columbia children’s Hospital Policy 1. Mechanical valve: All patients with mechanical valve on the left side of the circulation should be anticoagulated with coumadin for three months. Coumadin is discontinued after three months and replaced by ASA(10 ㎎/㎏ per day) plus persantine (3 ㎎/㎏/day) indefinitely. Patients in atrial fibrillation or with a history of thromboembolism require life time anticoagulation (coumadin). Patient is then fully anticoagulated with coumadin when 18 years of age. 2. Porcine or bovine valves: All patients require coumadin for three months. Coumadin is discontinued after 3 months and replaced by ASA(10 ㎎/㎏ per day) and persantine (3 ㎎/㎏/day). 3. Homograft valve replacement: all patients require ASA(10 ㎎/㎏ per day). N. B. no heparin is given postoperatively as coumadin is started after 48 hours (per mouth or Nasogastric tube). Prothrombin time is to be kept between 1 -¹/₂to 2 times normal (15 -20 second)

Anticoagulation ØProthrombin time & INR • Determine by % • INR(international normalized ratio) • Mechanical vs. bioprostheis • Cardiac rhythm ; atrial fibrillation • Location of valve; aortic, mitral, tricuspid • Age ; old or young

Anticoagulation ØProthrombin time & INR

Anticoagulation ØDrug interaction with warfarin Potentiation Acetaminophen Alcohol(if liver D. ) Amiodarone Chloral hydrate Cefazolin Cimetidine Clofibrate Erythromycin Floxin antibiotics Fluconazole Isoniazid Lovastatin Metronidazole Omeprazole Phenylbutazone Phenytoin Propranolol Quinidine Tamoxifen Inhibition Azathioprine Barbiturates Carbamazepine Chlordiazepoxide Cholestyramine Cyclosporine Narcillin Sucralfate No Effect Alcohol (if no liver D. ) Antacids Atenolol Bumetanide Diltiazem Famotidine Ibuprofen Ketorolac Ketoconazole Metoprolol Nizatidine Ranitidine Vancomycin

Mechanical Valve Implantation ØPathogenesis of thromboembolism • The pathogenesis is a complex phenomenon, occurring through an interaction of a of prosthesis-related and patient-related factors • Damaged perivalvular tissue and deposition of fibrinogen on the valve surface activate platelets as soon as blood starts flowing across the valve and this leads to immediate platelet adhesion and aggregation, and within 24 hours after surgery, platelet deposition on the Dacron sewing ring can be imaged radiographically • Coagulation factors are also directly activated after valve implantation, leading to further clot formation as a result of the inherent thrombogenicity of the prosthetic material and sites of denuded tissue (valve excision site) • Transprosthetic turbulent flow leads to regional increases in shear stress, structurally damaging the endocardium, causing a loss of local resistance to thrombosis.

Mechanical Valve Implantation ØThromboembolic mechanism • Strong risk factor for thromboembolic complications, especially in the first three to six months after surgery • First, the pathologic sequelae of the patients' inherent valvular disease (atrial fibrillation, dilated left atrium, and dilated left ventricle) may predispose to areas of stasis and thrombus formation • Second, the increased thromboembolic risk early reflect incomplete endothelial proliferation on the raw intracardiac surfaces, sewing ring, and suture knots in the initial postoperative period • Early thromboembolic risk can also be attributed to inconsistencies of oral anticoagulation management. • During the first six months, the thromboembolic risk is up to seven times greater than in the after months and years.

Mechanical Valve Implantation ØEarly thromboembolic risk • The early thromboembolic risk associated with the placement of a mechanical prosthesis depends on the complex interactions between the recipient and valve, the intrinsic thrombogenic properties of the mechanical valve components, and the diligent management of postoperative anticoagulation. • Variable or inadequate anticoagulation, defined as an INR 25% or more below therapeutic range, has been demonstrated to increase the incidence of thromboembolism 2 to 6 times, especially in the postoperative period

Mechanical Valve Implantation ØAnticoagulation therapy • In patients not receiving anticoagulation therapy, the average rate of major thromboembolism is estimated to be 4 to 8 per 100 patient-years and this risk is reduced to 2. 2 per 100 patient-years with antiplatelet therapy, and further reduced to 1 per 100 patient-years with oral warfarin • Recommended, in their most recent guidelines, that contemporary mechanical valves in the aortic position be anticoagulated with a target INR of 2. 0 to 3. 0, and mechanical valves in the mitral position be anticoagulated with a target INR of 2. 5 to 3. 5 [.

Mechanical Valve Implantation ØAntiplatelet therapy • In the absence of anticoagulation, antiplatelet therapy seems to be insufficient to prevent thrombi. • Because platelet aggregation occurs despite anticoagulation, the co-administration of antiplatelet agents with anticoagulation has been advocated to reduce the frequency of thromboembolic complications • Recommended that the addition of aspirin (80 to 100 mg/day) to warfarin be strongly considered for all patients with mechanical valves, for patients who have had an embolus while on warfarin therapy, those with vascular disease, or those with hypercoagulability

Mechanical Valve Implantation ØEarly anticoagulation strategies • The three common early postoperative anticoagulation strategies (1) oral warfarin starting on postoperative day one, without the use of therapeutic heparin anticoagulation; (2) intravenous unfractionated heparin beginning in the early hours after surgery, oral warfarin starting on postoperative day one, and the continuation of heparin until a therapeutic INR has been achieved; (3) low molecular weight heparin (LMWH) beginning in the early hours after surgery, oral warfarin starting on postoperative day one, and the continuation of LMWH until a therapeutic INR has been

Mechanical Valve Implantation ØStrategies • Oral warfarin alone Aanticoagulation with oral warfarin alone has been advocated as the safest regimen • Intravenous unfractionated heparin and oral warfarin Because the risk of thromboembolism is greatest in the early postoperative period (within 24 hours), with oral anticoagulation starting on the first postoperative day • 3. Low molecular weight heparin and oral warfarin Better safety profile with less thrombocytopenias, less bleeding, a more predictable and rapidly reached anticoagulant effect, the possibility of self-administration without laboratory monitoring, and shorter hospital stays

Anticoagulation ØThromboembolic level (TEL) • TEL 1; Presence of nonobstructive thrombus in the vicinity of the prosthetic valve as identified by clinical imaging (echocardiography); • TEL 2; Documented evidence of peripheral limb and visceral embolization (solid organs, coronary thrombus); • TEL 3; Documented evidence of central nervous system embolization (transient ischemic attack or cerebrovascular accident); • TEL 4; Prosthesis thrombosis requiring thrombolysis or emergency surgery; • TEL 5; A fatal thromboembolism.

Anticoagulation ØBleeding level (BL) • BL 1; Mild bleeding such as recurrent epistaxis or periodontal bleeding (more than two events) and gastrointestinal bleeds not requiring hospitalization or transfusions; • BL 2; Documented large pericardial effusion (>1 cm thickness on echocardiography); • BL 3; G-I bleeding requiring hospitalization, transfusion, endoscopic intervention or surgery; • BL 4; Documented cardiac tamponade requiring intervention; • BL 5; Documented CNS hemorrhage • BL 6; Fatal bleeding.

Anticoagulation ØTissue valved conduit replacement • Small patients with a greater mismatch between conduit size and normal valve size, prophylactic anticoagulation is recommended. • Due to the initially good overall performance, the Contegra bovine jugular vein conduit has become our preferred device for RVOT reconstruction. • Anticoagulated with heparin during their hospital stay followed by aspirin (10 mg/d) after discharge until they gain a weight of 5 to 6 kg. Since the introduction of this regimen we have not observed any other case of conduit valve thrombosis

Anticoagulation Ø Systemic-pulmonary shunt • PTFE conduit in Fontan patient received warfarin for 6 -12 months for anticoagulation to maintain an INR between 2. 5 and 3. 0. In addition, they were administered aspirin (5 mg/kg per day), which was continued indefinitely. • Trend in recent years toward using smaller shunts has contributed to a decrease in perioperative mortality due to excessive pulmonary blood flow but perhaps also to an increase in the incidence of shunt thrombosis • Shunt size is made more difficult by variations in technique such as the location of the proximal end of the shunt and its length

Anticoagulation ØTissue valve implantation • Warfarin was given to patients in sinus rhythm for the first 3 months postoperatively, then aspirin at a dose of 150 mg. • Keep on warfarin in patients in chronic atrial fibrillation and maintain the INR between 2. 5 and 3. 5. • Aanticoagulate our patients with tissue valves for the first 3 months postoperatively because thromboembolic risk outweighs the risk of bleeding in this group of patients • Thromboembolic rates in patients with aortic pericardial valves parallel those observed in patients with aortic porcine valves

Ideal Anticoagulation ØFactors of clinical situations • Valve replacement MVR, AVR, DVR, TVR Mechanical vs. tissue • Bentall operation • Mitral ring annuloplasty • Graft replacement of large vein • Pulmonary embolism, deep vein thrombosis • Atrial fibrillation, LA thrombi

Ideal Anticoagulation ØIdeal levels of INR • • Mitral valve replacement( 2. 5 to 3. 5 INR ) Aortic valve replacement(2. 0 to 3. 0 INR) Tricuspid valve replacement Pulmonary valve replacement Annuloplasty rings Extracardiac conduit Fontan operation Prosthetic angioplasties

Anticoagulation ØChoice of prosthesis • The incidence of anticoagulation-related complications such as bleeding and thromboembolic events increase sharply with advanced age • Oral anticoagulation is required lifelong, some may argue that implantation of bioprostheses should be preferred instead of mechanical prostheses in order to reduce the risk of anticoagulation-related complications with advanced age

Postoperative Blood Loss ØFactors • • Prior intake of antiplatelet drugs Endothelial response to cardiopulmonary bypass Systemic inflammatory response Systemic hypothermia Heparin excess and heparin rebound Platelet dysfunction and fibrinolysis Type of operation, reoperation, duration of CPB Presurgical anticoagulation status

Hemostasis ØPhysiology • Vascular function, which consists of three discrete layers; intima, media, and adventitia. The intima comsists of a monolayer of nonthrombogenic endothelial cells and an internal elastic membrane. The media consists of smooth muscle cells and the adventitia, external elastic lamina and membrane and supportive connective tissues. • The platelets, which must be normal in both number and function • The plasma protein, which include procoagulants, anticoagulants, and fibrinolytic proteins

Anticoagulants ØWarfarin • Interfere with vitamin K –mediated formation of clotting factors, including prothrombin as well as factor II, VII, IX and X, ; warfarin may also block the release of prothrombin from the liver • The absorption of vitamin K , as well as warfarin, is influenced by bile salts , dietary fat and in addition, affected by gastrointestinal tract transit time and intrinsic hepatic function and oral antibiotics that alter the gut flora • The maximam teratogenic action occurs between 6 and 9 weeks of pregnancy(oral anticoagulants cross the placenta and produces fetal abnormality)

Anticoagulants ØWarfarin • Action; interfere with hepatic synthesis of vitamin K – dependent coagulation factors(II, VII, IX, X) • Stability; protect from light in IV form(inject over 1 -2 minutes) • Dose adjustment in hepatic disease • Dietary consideration; foods in high vitamin K inhibit anticoagulant effect • Contraindications; hypersensitivity to warfarin or any components of formulation of bleeding tendency • Adverse reaction; bleeding is major and others nonspecific & some allergic

Warfarin Ø Pharmacokinetics • Onset of action; anticoagulation effect from oral 36 -72 hours, peak therapeutic effect 5 -7 days, INR increase in 36 -72 hours, IV administer as a slow bolus injection 2 -5 mg/day • Absorption; rapid , oral • Stability; protect from light in IV form(inject over 1 -2 minutes) • Duration; 2 -5 days • Metabolism; hepatic • Half life elimination; 20 -60 hours

Aspirin ØPharmacokinetics • Mechanism of action; Inhibits prostaglandin synthesis, acts on the hypothalamus heat-regulating center to reduce fever, blocks prostaglandin synthetase action which prevents formation of the platelet-aggregating substance thromboxane A 2 • Duration; 4 -6 hours, rapid absorption, & rapid dstribution and cross the placenta and enter fetal circulation and also enters breast milk • Metabolism; hydrolyzed to salycylate(active) by esterase in GI mucosa, RBC, blood; primarily by hepartic conjugation; metabolic pathways are saturable

Aspirin ØActions v Mechanism • Aspirin inhibits platelet aggregation by irreversible inhibition of platelet cyclooxygenase and thus inhibits the generation of thromboxane A 2 v Child dose • Antiinflammatory, 60 -80 mg/day/Kg in every 4 -6 hours • Antiplatelet effects; 3 -5 mg/Kg– 5 -10 mg/Kg in single dose • Mechanical prosthetic valve 6 -20 mg/Kg in single dose v Adult dose • 75 -325 mg/day in CABG, 80 -325 mg/day in PTCA, 160325 mg in stent, 30 -325 mg/day to prevent stroke(upto 1300 mg)