Author + information
- Susan P. Bell,
- Douglas Adkisson,
- Mark Lawson,
- Li Wang,
- Henry Ooi,
- Douglas Sawyer and
- Marvin Kronenberg
Supply-demand energy imbalance resulting in myocardial “energy starvation” may contribute to the pathophysiology of heart failure in non-ischemic dilated cardiomyopathy (NIDCM). Spironolactone is known to facilitate left ventricular (LV) reverse remodeling and hence improvement in NIDCM. Cardiac magnetic resonance imaging (CMR) and [11C] acetate PET imaging were used to assess this hypothesis in NIDCM, and that aldosterone blockade facilitates reverse remodeling, improving the LV supply-demand energy imbalance.
12 subjects with NIDCM underwent CMR and [11C] acetate PET imaging at baseline and after > 6 months of spironolactone therapy. The myocardial perfusion index (MPI) was calculated as the normalized rate of myocardial signal augmentation following gadolinium at rest and during hyperemia. The myocardial perfusion reserve index (MPRI) compared MPI during adenosine to rest. The monoexponential clearance rate of [11C] acetate, kmono was used to calculate the work-metabolic index (WMI), a measurement of LV efficiency.
At baseline there was relative hypoperfusion of the subendocardium (MPRI = 1.63) compared to the subepicardium (MPRI= 1.80, P < 0.001), which improved significantly following spironolactone therapy to 1.80 (P<0.001). The relation of oxidative metabolism to demand, as defined by the ratio, kmono/rate-pressure product, increased from 5.5 (min-1/ beats min – mmHg) to 6.4 (P=0.003). The WMI increased from a median of 3.4 × 106 (ml × mmHg/m2) to 5.4 × 106(P=0.001). Reverse remodeling was observed with increased LVEF by 9% (P=0.002) and LV stroke volume by 30ml (P=0.002), and decreased LV mass index by 10gm/m2 (P=0.002) and LV wall stress by 47kPA (P < 0.001).
NIDCM is associated with subendocardial hypoperfusion coupled to impaired myocardial oxidative metabolism consistent with the energy starvation hypothesis. Spironolactone therapy > 6 months was associated with reverse remodeling and with a reduction of subendocardial energy starvation and demonstrates this concept for the first time in patients with non-ischemic heart failure.
Moderated Poster Contributions
Poster Sessions, Expo North
Saturday, March 09, 2013, 10:00 a.m.-10:45 a.m.
Session Title: Heart Failure: Innovations in Medical Therapy
Abstract Category: 17. Heart Failure: Therapy
Presentation Number: 1133M-270
- 2013 American College of Cardiology Foundation