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Ischemic Cardiomyopathy
Ischemic Cardiomyopathy
“The most common cause of heart failure in developed countries.”
He J, Ogden LG, Bazzano LA, et al. Risk factors for congestive heart failure in US men and women: NHANES I epidemiologic follow-up study. Arch Intern Med 2001; 161:996.
Definition of Ischemic Cardiomyopathy
“Impairment of left ventricular function that results from coronary artery disease”
Pathogenesis
Irreversible loss of myocardium from prior MI with ventricular remodeling
AND
Partially reversible loss of contractility due to reduced function of ischemic but still viable myocardium (Hibernating Myocardium)
Hibernating Myocardium
“Contractile dysfunction in viable myocardium that improves after revascularization or perhapmedical therapy”
Chareonthaitawee P, Gersh BJ, Araoz PA, Gibbons RJ. J Am Coll Cardiol. 2005 Aug 16;46(4):567-74.
http://www.britannica.com/blogs/wp-content/uploads/2011/05/dormouse.jpg
“No randomized trials of revascularization in patients with coronary artery disease with decrease LVEF”
“Multiple observational study suggesting improvement in outcome with CABG”
Current Recommendation for CABG in patient with poor LV function
1. Significant left main disease
2. Left main equivalent disease ( ≥ 70 % stenosis of proximal LAD and Proximal LCX)
3. Proximal LAD stenosis with two or three vessel disease
Coronary-Artery Bypass Surgery in Patients with Left Ventricular
Dysfunction(STICH trial)
STICH = Surgical Treatment for Ischemic Heart Failure
Methods
Study Design
• Non-blinded, Randomized study.
• Sponsored by NHLBI and Abbott Laboratories
• Design to have 90% power to detect a 25% reduction in mortality with CABG as compared with medical therapy alone
Study Patients
• CAD amenable to CABG
• EF of 35% or less
Study Procedures
• CABG is performed by cardiac surgeon in whom have operative death rate less than 5%
• Patients are followed at 30 days, every 4 months then every 6 months on next year
Primary Outcome
• Rate of death from any cause
Secondary Outcome
• “Rate of death from CVS cause”
• “Rate of death from any cause or hospitalization from cardiovascular cause”
Statistical Analysis
• Intention to treat analysis
• Kaplan Meier method
• As treated analysis
Result
Study Population
• 1212 Patients from 22 countries
• 602 has medial therapy
• 610 has CABG + Medical Therapy
CABG group610 Patients
529 (95%) got surgery
63 also got mitral valve
repair
Medical Group602 Patients
100 (17%) end up getting surgery
1. Progressive symptoms2. Acute decompensation3. Family ‘s decision4. Physician’s decision
Follow-up
• 5 of 1212 patients were loss to follow up.
• Median length of follow-up is 56 months
Outcome Medical Therapy CABG
Rate of death from any cause
41 % 36 %
Primary Outcome
Hazard Ratio with CABG 0.86 P Value 0.12
Secondary Outcome
Outcome Medical Therapy CABG Hazard Ratio
Death from cardiovascular
cause33 % 28 %
0.81(0.66-1.00)
Death from any cause or admit for
HF54 % 48 %
0.84(0.71-0.98)
As-treated analysis
CABG620 Patients
including cross over
Medical Management592 Patients
As-treated analysis
Limitations
• Non blinded study has an effect on non fatal outcome
• Trial was design to detect 25% reduction in mortality with CABG
• Limited power and limited duration of follow-up