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