Dilated cardiomyopathy surgery
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-in-Chief: Sachin Shah, M.D.
Overview
Surgery and Device Based Therapy
Implantable cardiac defibrillators in dilated cardiomyopathy
Implantable cardiac defibrillators (ICDs) have also been extensively studied in systolic heart failure. A survival benefit has also been shown in select patient populations. ICDs are implanted in patients with systolic heart failure for primary prevention of sudden cardiac death. The AHA/ACC (American Heart Association/American College of Cardiology) class I indications for ICDs for primary prevention are: 1. EF < 35% due to prior MI, 40 days post MI, NYHA class II or III. 2. EF < 35% NYHA class II or III non ischemic dilated cardiomyopathy. 3. EF < 30%, prior MI, 40 days post MI, NYHA I. 4. EF < 40%, prior MI, NSVT and inducible VT/VF at EP study.
There are four major studies that have helped shape these indication for an ICD. The MADIT I evaluated NYHA class I to III heart failure patients with an EF < or = to 35%, with NSVT and inducible VT or VF on EP study and randomized 196 patients to ICD versus conventional medical therapy. The patients who received ICDs had improved survival at 5 years. 60% of patients received shocks by 2 years.[1] The findings from this study are encompassed in the remaining three studies.
Madit II randomized 1232 patients who had a prior MI > 1 month prior to enrollment, an EF < or = to 30% to ICD or medical therapy and after a follow up of an average of 20 months there was a survival advantage in the ICD group. The number needed to treat was 18 patients. [2]
MUSTT randomized 704 patients with an EF < or = to 40%, NSVT and inducible VT/VF at EP study to arrhythmia therapy (medications and ICDs) or no antiarrhythmia. At 5 years there was a 27 risk reduction in mortality in the antiarrhythmia group. The relative risk of mortality when comparing ICD vs. no ICD was 0.24. There was no difference in mortality in the antiarrhythmic medication vs. no antiarrthymic medication subgroups.[3]
SCD-HeFT randomized 2521 patients with class II or III CHF and EF < or = to 35% (ischemic or non ischemic) to three arms: 1. conventional therapy, 2. conventional therapy plus amiodarone, and 3. conventional therapy plus an ICD. After a median follow up of 46 months there was a relative risk of death of 0.77 in the ICD arm. Findings were similar in the ischemic and non-ischemic subgroups.[4]
NYHA class IV heart failure is a contraindication to ICD placement.
Indications for Surgery
In patients who have severe heart failure and are refractory to medical therapy cardiac transplantation may be an option (based upon patient characteristics such as age and comorbidities as well as disease characterisitics such as the etiology of dilated cardiomyopathy). As a bridge to cardiac transplantation multiple mechanical devices have been used. The most durable device is the LVAD (left ventricular assist device), certain patient populations not suitable for cardiac transplantation may also undergo LVAD placement by a cardiac surgeon as a "destination LVAD." This may be considered a palliative measure for end-stage heart failure patients. Other devices which may be more limited in the duration of use include the aortic balloon pump, Impella, and the PVAD (peripheral ventricular assist device) one of which is the Tandem Heart.