Am Heart Hosp J. 2011;9(2):107–11


Lozenge Reference


Review


Viability Studies—Comparison of Techniques Dmitriy Kireyev, MD, FACC,1


Kenan Adib, MD,2 Mofid Khalil, MD, FACC3 Kian Keong Poh, FRCP, FACC,2 and Michael F Wilson, MD, FACC3


Ischemic cardiomyopathy is one of the most common causes of congestive heart failure. Despite multiple therapeutic options, morbidity and mortality remain high. Revascularization is one of the best options to improve ejection fraction and survival in patients with hibernating myocardium. This article discusses the role of positron emission tomography (PET), single-photon emission computed tomography (SPECT), dobutamine stress echocardiography (DSE), and magnetic resonance imaging (MRI)-based viability studies and their comparative evaluation.


than 5.8 million cases have been reported, with approximately 670,000 new cases each year.2


M Heart failure


is a diagnosis associated with high morbidity and mortality. CHF can be categorized as either systolic (reduced left ventricular ejection fraction) or diastolic (preserved ejection fraction) heart failure. Systolic heart failure may be due to multiple causes, one of these being dilated cardiomyopathy which can develop secondary to ischemic myocardium.


Angiotensin-converting enzyme inhibitors and some angiotensin receptor blockers have been demonstrated to significantly decrease morbidity and mortality in patients with CHF.8–14


Medical therapy of CHF due to systolic dysfunction has evolved significantly during the last several decades. Beta-blockers, such as bisoprolol, carvedilol, and metoprolol XL/CR, were shown to improve mortality and reduce hospitalizations in patients with systolic heart failure.3–7


Competitive


antagonists of aldosterone, such as spironolactone, as well as the aldosterone receptor blocker eplerenone further decrease mortality when added to standard therapy for CHF.15,16


Cardiac resynchronization


ore than 20 million people worldwide are estimated to have been diagnosed with congestive heart failure (CHF).1


In the US, more


therapy improves symptoms and quality of life and decreases mortality in patients with CHF and cardiac dyssynchrony.17


The most common cause of CHF is ischemic cardiomyopathy (ICM).18


A significant percentage of


patients (more than 50 % in some studies) with ICM will have decreased ejection fraction but viable myocardium.19,20 Revascularization remains one of the best treatment options in such cases.21


Multiple studies have shown an improvement in left ventricular ejection fraction and functional status and better long-term prognosis in patients undergoing revascularization based on the presence of viable myocardium.22–25


The outcome after revascularization is


related not only to the presence, but also to the extent of viable myocardium, thus making it especially important to quantify the amount of viable myocardium so as to properly assess the risks and benefits of potential interventions.26–28


Although multiple retrospective trials


and meta-analyses showed the benefit of using viability studies, one of the more recent substudies of the Surgical treatment for ischemic heart failure (STICH) trial did not show the same. Even though presence of viable myocardium, as assessed by single-photon emission


• 1. State University of New York, Buffalo and Cambridge Health Alliance, Cambridge MA; 2. National University Heart Center, Yong Loo Lin School of Medicine, National University of Singapore; 3. Cardiology Department, Kaleida Health, Buffalo


• Correspondence: Dmitriy Kireyev, MD, FACC, Cambridge Health Alliance, Whidden Memorial Hospital, 103 Garland Street, Everett, MA 02149. E: dkireyev@cha.harvard.edu


Winter 2011 Viability Studies—Comparison of Techniques 107


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