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SURGICAL MANAGEMENT OF HEART FAILURE
 

SURGICAL MANAGEMENT OF HEART FAILURE

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THE WHOLE SPECTRUM OF SURGICAL MANAGEMENT IS DESCRIBED

THE WHOLE SPECTRUM OF SURGICAL MANAGEMENT IS DESCRIBED

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    SURGICAL MANAGEMENT OF HEART FAILURE SURGICAL MANAGEMENT OF HEART FAILURE Presentation Transcript

    • Definition “a complex clinical syndrome that can result from any structural or functional cardiac disorder that impairs the ability of the ventricle to fill with or eject blood‟‟
    • Surgery for heart failure? It would appear so:  by removing the primary ventricular insult, so permitting recovery, or  by amelioration of the damaged ventricle with improvement of cardiac output (so called „„reverse remodelling‟‟ or „„ventricular restoration surgery‟‟). 
    • OPERATIONS TO REVERSE REMODEL THE FAILING HEART Intervention to improve CO by reducing ventricular afterload: – intra-aortic balloon pumping (IABP) – resection of obstructed left ventricular outflow in HCM Surgical procedures to improve cardiac output by reducing left ventricular size („„La Place surgery‟‟): – myo-splint – CorCap or Acorn device – Batista operation – left ventricular aneurysmectomy
    • Surgical strategies to re-power the failing heart: Mechanical: – cardiac resynchronisation therapy (CRT) – ventricular assist devices (left (LVAS), right (RVAS), bi- (BiVAS) and total artificial heart) Biological: – dynamic cardiac myoplasty – heart transplantation – cell transplantation – gene therapy – up-regulation of natural pathways
    • Surgical options Coronary artery revascularization  Valve surgery  Left ventricular reconstruction  Passive cardiac support devices  Assist devices  Cardiac transplantation 
    • Coronary artery revascularization Ischemic cardiomyopathy:  myocardial dysfunction that arises secondary to occlusive or obstructive coronary artery disease
    • Three inter-related pathophysiologic process:  Myocardial stunning  Myocardial hibernation  Myocyte cell death
    •  Clinical factors for selection of suitable heart failure patients the presence of angina,  severity of heart failure symptoms,  LV dimensions,  degree of hemodynamic compromise, and  comorbidities.   Other major technical issues to be considered are adequacy of target vessels for revascularization &  adequate conduit strategy. 
    •  The most important determinant, however, is the extent of jeopardized but still viable myocardium.  Current studies have suggest at least 25% of the myocardium should be viable
    • Risks of CABG  Studies have indicated that for patients with clinical heart failure, perioperative mortality rates will range from approximately 2.6% to 8.7%, depending on age and presence of one or more comorbid conditions
    •  CABG Patch trial – Angina - HF - : 1.3% – Angina - mild HF (NYHA I/II): 4.8% – Angina - severe HF(NYHA III/IV): 7.4% SHOCK trial  1-year mortality CABG : 42% to 56% medical therapy - 56% to 75%  IABP decreased in-hospital mortality but had no effect on 1-year survival. 
    • Benefits of Coronary Artery Bypass Grafting  The beneficial effect of revascularization should, theoretically, result from improved blood flow to hypoperfused but viable myocardium, with a subsequent improvement in LV function and clinical outcomes.  Alleviation of ischemia may also lessen the tendency toward proarrhythmias, thereby reducing the incidence of sudden cardiac death.  Accordingly, coronary artery revascularization has the potential to improve symptoms of heart failure, LV function, and survival.
    • Improvement in LV function
    • Symptomatic improvement In a study from Verona, 167 patients with an average LVEF of 28%, with angina and heart failure symptoms, demonstrated – Freedom from angina - 98% and 81% at 1 and 5 years. – Freedom from heart failure - 78% and 47% at 1 and 5 years. – Both - 54% of patients
    •  A blood flow–metabolism mismatch of more than 18% was associated with a sensitivity of 76% and a specificity of 78% for predicting a change in functional status after revascularization.  Another study showed a 34% increase in exercise capacity from 5.6 to 7.5 METs in the group of patients with revascularization PET mismatch.
    • Survival benefit SVD DVD TVD
    •  DUKE data base: CABG > medical therapy – regardless of age, LVEF, NYHA class, or presence of angina  Survival: CABG MEDICAL THERAPY 1 YEAR 83% 74% 5 YEARS 61% 37% 10 YEARS 42% 13%
    •  meta-analysis of 24 studies (3088 patients) – revascularization decreased the risk of death by 79.6% in patients with evidence of viable myocardium – annual mortality of 3.2% compared with 16.0% for patients without revascularization.  The type of viability study did not affect the clinical outcomes.  In contrast, patients without viability showed no survival benefit with revascularization.
    •  A study of 908 CABG patients looking at mid- and long-term results showed the independent risk factors for short- and long-term event-free survival are – quality of coronary arteries, – degree of myocardial viability, – completeness of revascularization, – number of grafts, and – elective operation.
    • STICH TRIAL
    • (1) CABG combined with medical therapy improves long-term survival compared with medical therapy alone; and (2) SVR provides additional long-term survival benefit when it is combined with CABG and medical therapy
    •  Current ACC/AHA guidelines for CABG in patients with poor LV function recommend surgery Class I - patients with left main or equivalent disease, Class IIa - patients with viable noncontracting muscle, Class III - without evidence of ischemia or viability.
    • Surgical options Coronary artery revascularization  Valve surgery  Left ventricular reconstruction  Passive cardiac support devices  Assist devices  Cardiac transplantation 
    • VALVE SURGERY MITRAL REGURGITATION:  Progressive LV remodeling progressive LV dilation more spherical shape Functional MR • annular dilation, • papillary muscle displaceme • chordal tethering.
    • Consequences:  increased preload,  increased wall tension,  increased LV workload, Heart failure Significance:  independent risk factor of poor outcome, in both nonischemic and ischemic causes
    • BOLLING hypothesis  there is an “annular solution for a ventricular problem . . . such that reconstruction of the mitral valve annulus‟ geometric abnormality by an undersized ring restores valvular competency, alleviates excessive ventricular workload, improves ventricular geometry and improves ventricular function.”
    • the reduction of the annulus by a small ring reduces a radius of curvature of the LV at the base equatorial and apical levels restore a more elliptical ventricular shape reverse remodelling
    • Acorn trial
    •  Operative morality 2% – 5%  Recurrent MR – 30% - 40%  No survival benefit
    • Surgical options Coronary artery revascularization  Valve surgery  Left ventricular reconstruction  Passive cardiac support devices  Assist devices  Cardiac transplantation 
    • Left ventricular reconstruction The goals of ventricular reconstruction are – to remove or to exclude the infarcted segment – to restore an elliptical ventricular chamber – to diminish remote wall stress – to promote helical fiber orientation and – to increase thickening of the akinetic or dyskinetic portion of the chamber – to reduce end-systolic volume – to diminish mitral insufficiency, and – to eliminate residual ischemia
    • The goal is to reduce ESV by at least 30% while ensuring that the ventricle is not too small.
    •     The RESTORE (Reconstructive Endoventricular Surgery returning Torsion Original Radius Elliptical shape to the left ventricle) Concomitant procedures included CABG in 95% and mitral valve repair in 22%. The operative mortality - 5.3%. At 5 years, the overall survival was 68% ± 2.8%, and freedom from hospital readmission for heart failure was 78%.
    •  Risk factors for death – LVEF less than 30% – LV end-systolic volume index ≥80 mL/m2 – advanced NYHA functional class, and – age older than 75 years  Decrease in LV ESVI (from 80.0 ± 5.1 to 56.0 ± 34.3 mL/m2)  Increase in LVEF (from 29% ± 11.0% to 39% ± 12.3%).  30-day mortality of 1% and 1-, 3-, and 5-year survival of 92%, 90%, and 80%, respectively.
    • The SVR portion of the STICH trial  Bypass surgery alone was done in 499 patients, and CABG plus SVR was performed in 501 patients.  Median follow-up of 48 months.  There were no differences in deaths from any cause or hospitalization for cardiac causes during the 5 years of the study.
    • Criticism:  The average %reduction in ESV after CABG plus SVR was only 19%.  This is below the accepted criterion for successful LV reconstruction of a minimum of 30% reduction in ESV.  In addition, the absolute end-systolic volume index in the STICH patients undergoing CABG plus SVR was 67mL/m2.
    • The results of Menicanti
    • Surgical options Coronary artery revascularization  Valve surgery  Left ventricular reconstruction  Passive cardiac support devices  Assist devices  Cardiac transplantation 
    • Passive Cardiac Support Devices  The CorCap cardiac support device (CSD) is a fabric mesh sock that is surgically implanted around the heart.  The CSD is designed to provide circumferential diastolic support and to reduce LV wall stress, thereby leading to reverse cardiac remodeling.
    •  The Acorn trial - CSD-treated patients – fewer cardiac procedures – improvement in NYHA class. – decrease in LV EDV and ESV→ reverse cardiac remodeling, – increase in the LV sphericity index → indicative of a more elliptically shaped ventricle – improvement in quality of life scores. Additive benefits with mitral valve surgery  Continued benefits up to 5 years, with no evidence of constrictive physiology  Currently not approved by the FDA. 
    • Surgical options Coronary artery revascularization  Valve surgery  Left ventricular reconstruction  Passive cardiac support devices  Assist devices  Cardiac transplantation 
    • Cardiac transplantation  Christiaan Barnard performed the first clinical human cardiac transplantation in 1967.  The most potent predictor of outcome in ambulatory patients with heart failure is a test of symptom-limited metabolic stress to calculate peak oxygen consumption (V.o2)  A peak V.o2 of <12 mL/kg/min is indicative of a poor prognosis, with a survival rate that is lowerthan that for transplantation
    •  Each patient undergoes immunological evaluation, which is increasingly sophisticated, to determine ABO blood type; antibody screening; testing for panel reactive antibody (PRA); and human leukocyte antigen (HLA) typing.  The presence and levels of anti-HLA antibodies is determined by cytotoxic testing in which the recipient‟s serum is incubated with lymphocytes from 30 to 60 individuals that represent a wide range of HLA antigens.  The PRA value is expressed as a percentage of cell panel members that undergo cytolysis and is considered positive if more than 10% of the cell panel members undergo cytolysis.
    • The acceptable “cold ischemia” time for cardiac transplantation is approximately 4 hours.  The two most common surgical approaches for the implantation of the donor heart are the biatrial and bicaval anastomoses.  The biatrial anastomosis technique has long had a reputation for being simple, safe, and reproducible;  four suture lines are made in the left atrium, pulmonary artery, aorta, and 
    •  The bicaval anastomosis technique was introduced in the early 1990s with the intentions toreduce right atrial size, to minimize distortion of the recipient heart, to preserve atrial conduction pathways, and to decrease tricuspid regurgitation.  This alternative procedure entails five anastomoses: left atrium, pulmonary artery, aorta, inferior vena cava, and superior vena cava.
    •  Although there has been no prospective trial to establish th superiority of either technique, the bicaval technique is now performed more often in the United States, primarily because it appears to decreasethe need for permanent pacemakers in transplant recipients.
    •  The most common reason for failure to wean a heart transplant recipient from cardiopulmonary bypass is right-sided heart failure, evidenced by a low cardiac output despite a rising central venous pressure.  Right ventricular function may be enhanced with inotropic agents and pulmonary vasodilators,
    • Most immunosuppressive regimens begin with the simultaneous use of three classes of drugs:  Glucocorticoids,  Calcineurin inhibitors, and  Antiproliferative agents. 
    • Outcomes Survival:  During the first year after transplantation, early causes of death are graft failure, infection, and rejection, with an overall 1-year survival rate of 87%.  Nonspecific graft failure accounted for 41% of deaths during the first 30 days after transplantation, whereas noncytomegalovirus infection was the primary cause of death during the first
    •  After 5 years, CAV and late graft failure (31% together), malignancy (24%), and noncytomegalovirus infection (10%) were the most prominent causes of death. Functional Outcomes  By the first year after transplantation surgery, 90% of surviving patients report no functional limitations, and approximately 35% return to work
    • Surgical options Coronary artery revascularization  Valve surgery  Left ventricular reconstruction  Passive cardiac support devices  Assist devices  Cardiac transplantation 
    • Mechanical Circulatory support Short – term: 1. Intra-aortic Balloon Pump 2. Abiomed Biventricular System 5000 3. Abiomed AB5000 4. Bio-Medicus Bio-Pump 5. Levitronix CentriMag 6. TandemHeart Percutaneous Transseptal VAD 7. Impella Devices
    • Bridge to transplantation 1. Thoratec Percutaneous Ventricular Assist Device System 2. CardioWest Total Artificial Heart 3. Novacor Ventricular Assist System 4. HeartMate XVE Left Ventricular Assist Device 5. HeartMate II Left Ventricular Assist Device
    • Future devices: 1. Jarvik 2000 2. MicroMed DeBakey VAD 3. HeartMate III 4. MVAD by HeartWare 5. Abiomed Total Artificial Heart