Download Prosthetic valve thrombosis

Complications in Valvular
Heart Surgery
นพ.ณัฐพล อารยวุฒิกลุ
ศูนย์ โรคหัวใจโรงพยาบาลลาปาง
Technique related complications
• Massive bleeding require
reoperation
• Heart block
• Stroke
• Perioperative MI
• Valve dysfunction
• Incomplete correction
Valve related complication
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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.
• 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
• Elevated D-dimers,
thrombocytopenia,
prolonged PT/PTT
• In adequated
heparinization during
CPB leading to
thrombosis in the
oxygenator of the pump
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 Thorac Surg 46 Nov 1988
LV Rupture Type 1
LV Rupture Type 2
LV Rupture Type 3
Repair LV rupture
Repair LV rupture
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
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
Perioperative MI
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
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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
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
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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)
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
Prosthetic-Patient Mismatch
• Prevention
- Implant another type of
prosthesis with large EOA such
as stentless valve
- Enlarge the aortic root