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Complications in Valvular Heart Surgery. นพ. ณัฐ พล อารย วุฒิกุล ศูนย์โรคหัวใจโรงพยาบาล ลำปาง. Technique related complications. Massive bleeding require reoperation Heart block Stroke Perioperative MI Valve dysfunction Incomplete correction. Valve related complication.
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Complications in Valvular Heart Surgery นพ.ณัฐพล อารยวุฒิกุล ศูนย์โรคหัวใจโรงพยาบาลลำปาง
Technique related complications • Massive bleeding require reoperation • Heart block • Stroke • Perioperative MI • Valve dysfunction • Incomplete correction
Valve related complication • Thromboembolism and Bleeding • Endocarditis • Structural deterioration • Prosthetic valve thrombosis • Prosthetic-Patient Mismatch
Serious bleeding • Mediastinal bleeding requiring reoperation 5-11%
Serious mediastinal bleeding • Infant 6 kg • 70 cc in first hour • 60 cc in second hour • 50 cc in third hour • Total 130 cc by fourth hour • Total 150 cc by fifth hour • Adult 50 kg • 500 cc in first hour • 400 cc in second hour • 300 cc in third hour • Total 1000 cc by fourth hour • Total 1200 cc by fifth hour
Preoperative precautions • Aspirins • Should be stopped 1 week prior to surgery • Clopidogrel and ticlopidine • Should be stopped at least 1 week prior to surgery • NSAIDs • Should be stopped 1 day before surgery • Warfarin • Should be discontinued 3 days before surgery
Predisposing comorbid metabolic abnormalities • Uremia • Plt dysfunction/impaired vWf action • Plt transfusion usually not effective • Adequately dialyzed preoperatively • FFP , Cryoprecipitate and DDAVP are considered
Predisposing comorbid metabolic abnormalities Acute liver dysfunction DIC eg IE pt. Elevated D-dimers, thrombocytopenia, prolonged PT/PTT In adequatedheparinization during CPB leading to thrombosis in the oxygenator of the pump • Impaired synthesis function of factor 2,7 9 10 • Fibrinogen and platelets may be low • Increased fibrinolysis process • Preop vitamin K , FFP and platelets must be transfused to correct or normalize PT and platelet counts
How to prevent postoperative bleeding • Strict avoidance of hypertension • Aware of heparin rebound ( up to about 6 hrs. postop) • Anti fibrinolytic drugs • Tranexamic acid • Load 2.5-100 mg per kg over 30 mins • Continuous infusion 1-4 mg/kg/hr over 1-12 hr. • Desmopressin(DDAVP) • Vasopressin analogue, increase factor 8 and von Willibrand’s factor • IV 0.3 microgram per kg
Left Ventricular Rupture • Left ventricular rupture • Major lethal complication of MVR • Mortality ~ 75% • Risk factors • Female sex, advanced age,small left ventricle, previous operation • Extensive retraction of papillary muscle, inadvertent injury to annulus, too large prosthesis, impingement by a valve strut and deep sutures to the myocardium
Left Ventricular Rupture Ann ThoracSurg 46 Nov 1988
Heart Block • Heart block requiring a permanent pacemaker ~1% following AVR and MVR
Heart Block • Heart block requiring a permanent pacemaker ~2-7% following TVR
Stroke • Incidence* • 4.8% in aortic valve surgery • 8.8% in mitral valve surgery • 9.7% in double valve surgery *Ann Thorac 2003;Feb 75(2) 472-8 *Ann Thorac 2003;Feb 75(2) 472-8
Stroke • Aortic plaque* • Intraop palpation can detect around 50% • TEE – better than manual palpation but less sensitive in the mid and distal ascending Aorta • Epiaortic U/S – sensitivity 96.8% *Chest 2005; 127:60-65
Stroke • Left Atrial clot • Air • Cardiac vent + Aortic root vent • Intraoperative CO2 blowing 6-8 L/min • Inversion of the left atrial appendage/obliterate LAA • Tilting of the table from side to side with inflation of the lungs to dislodge any pulmonary vein bubbles • TEE
Stroke • Valve position (mitral versus aortic), adequacy of anticoagulation, presence of atrial fibrillation, and patient comorbidities. • Interestingly, the risk of thromboembolism appears equal regardless of whether the prosthesis is a mechanical or bioprosthetic valve.
Perioperative MI • (TEE) was invaluable in confirming the diagnosis in the setting of acute ventricular fibrillation and new left bundle branch block. • Iatrogenic injury to coronary arteries is a known complication of aortic valve surgery, and was the likely source of the ischemia and resultant arrhythmia.
Valve Dysfunction • Sutures loop around the struts • Free ends of the sutures must be short and placed properly to avoid being caught in the closing prosthetic leaflets • Subvalvular tissue
Valve Dysfunction • Periprosthetic leakage • Usually there is no different between mechanical and bioprosthetic valve
Predisposing factors • annular calcification • Infection • PPM • Excessive tension on suture or annulus • Incorrect / insufficient number of sutures
Incomplete Correction • Residual regurgitation • Stenosis • SAM (Systolic anterior motion)
Systolic Anterior Motion • Adverse outcome after valve repair • Anterior leaflet obstruct LVOT • Etiology • Increased redundancy in leaflet tissue • Small annuloplasty ring
Systolic Anterior Motion • Treatment Medical Rx if parameter of repair is good • Avoid inotropic drug except for norepinephrine • Maintain adequate preload Surgical Rx • Posterior leaflet sliding procedure • Slightly oversized the annuloplasty ring • Use Alfieri stitch to A1/P1 • Implant Gortex suture to reduce height of anterior leaflet
Thromboembolism and Bleeding • Major causes of thromboembolism • Interrupted anticoagulant or inadequate INR • High risk group*: • Prior embolic complications • AF • Left atrial thrombus • Recent operation ( first operative year ) • Operation before the mid 1970s
Thromboembolism • MVR – more common due to AF and large LA • AF – important factor for thromboembolism • Multiple valve replacement higher embolic rate
Anticoagulant-related Hemorrhage • Incidence - 1%-4% per person year - same rate in MVR and AVR - Risk: increase in INR > 4.0
Prosthetic Valve Endocarditis • Early - within 2 months - incidence 1% per patient/year - mortality 50%-70% - highly destructive process valve ring abscess & paravalvular leaks and conduction disturbances
Prosthetic Valve Endocarditis • Early PVE has higher mortality rate ( 75% VS 43% ) due to • Predominance of nonstreptococcal mechanisms • More debilitated patients • Involve freshly implanted, nonendothelialized valve and sewing ring
Prosthetic Valve Endocarditis • Late - more than 2 months - Source of infection : Dental and Genitourinary tract - Mechanical sewing cuff - Bioprosthesis cusps(leaflets) less at sewing cuff paravalvular leaks rare
Prosthetic Valve Endocarditis • Indication for Surgery • Early prosthetic valve endocarditis (first 2 mo) • Heart failure with prosthetic valve dysfn • Evidence of perivalvular extension • Persistent infection after 7-10 d of adequate ATBs • Recurrent emboli despite appropriate ATBs • Infections due to organisms with poor response ATBs • Obstructive vegetation
Structural Deterioration • Bioprosthetic Valve Failure - freedom from valve deterioration for the two most commonly used bioprosthesis valve ( Carpentier-Edward and Hancock ) is between 60% and 80% at 10 years and drops sharply to 45% at 14 years - Mitral valve higher rate of failure
Prosthetic valve thrombosis • Any obstruction of a prosthesis by non infective thrombotic material • Incidence: 0.5-8% in Lt. sided mechanical Valve 20% in tricuspid position • Thrombosis 77% • Pannus 10.7% • Pannus + Thrombosis 11.6% • Mitral position more frequent than aortic position
Prosthetic valve thrombosis • Obstructive PVT abnormal dyspnea, heart failure • Non-obstructive PVT embolic episode • Echo findings: • Abnormal movement of prosthesis • Paraprosthetic thrombus • Abnormal transprosthetic flow • Mitral gradient > 8 mmHg, effective area < 1.3 cm2 • Aortic mean gradient > 40 mmHg Heart 2007;93:137-142
Prosthetic valve thrombosis • Surgery Mortality: 4% in pt with FC I-III 17.5% in pt with FC IV • Thrombolysis: success 82% mortality 10% systemic emboli 12.5% bleeding 2-5% J.Heart Valve Dis Vol.14. No.5. Sep 2005
Prosthetic valve thrombosis • Emergency operation is reasonable for patients with a thrombosed left-sided prosthetic valve and NYHA functional class III-IV or a large clot burden (IIa level C) • Fibrinolytic therapy is reasonable for thrombosed right-sided prosthetic heart valves with NYHA class III-IV or a large clot burden (IIa level C) ACC/AHA Practice Guidelines 2006
Prosthetic valve thrombosis • Fibrinolytic Rx may be considered as a first-line Rx for patients with a thrombosed left-sided prosthetic valve, NYHA class I-II, and a small clot burden (IIb level B) • Fibrinolytic Rx may be considered as a first-line Rx for patients with a thrombosed left-sided prosthetic valve, NYHA class III-IV or a large clot burden if Sx is high risk or not available (IIb level C) ACC/AHA Practice Guidelines 2006
Prosthetic valve thrombosis • Intravenous UFH as an alternative to fibrinolytic therapy may be considered for patients with a thrombosed valve who are in NYHA class I-II and have a small clot burden (IIb level C) ACC/AHA Practice Guidelines 2006
Which type of valve to be selected • Risks of anticoagulant-related bleeding • Risks of structural failure • Risk of reoperation • Underlying medical or surgical problems