Responding to a recent study showing that 40% of patients who receive CRT-ICD therapy do not benefit from the device (Sipahi, et al – 6/13/11), Wojciech Zareba, MD, PhD, stated that improving risk stratification of heart failure patients eligible for an implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy with a defibrillator (CRT-D) is essential.
He notes that patients with left bundle branch block QRS morphology derived the most benefit from CRT-D, however, additional methods are needed to further ensure benefit of this therapy. Dr. Zareba is Professor of Medicine, Director of Cardiology Clinical Research, and Director of the Heart Research Follow-up Program at the University of Rochester Medical Center. He was the Principal Investigator on a study conducted under a collaborative agreement between Vicor Technologies, and the University of Rochester and the Catalan Institute of Cardiovascular Sciences in Barcelona. Vicor Technologies is a biotechnology company focused on the commercialization of its PD2i Analyzer™, an innovative, non-invasive diagnostic employing its patented, proprietary PD2i® nonlinear algorithm. Physician use of the PD2i Analyzer™ is supported by an expanding body of literature documenting the PD2i® nonlinear algorithm as a metric for risk stratifying specific target populations for future pathological events, including diabetics for the presence of diabetic autonomic neuropathy (DAN), cardiovascular disease patients for death resulting from arrhythmia or congestive heart failure, and trauma victims for imminent death absent immediate lifesaving intervention.
Dr. Zareba is a world-renowned cardiac researcher. He serves as Principal Investigator of ECG Core Labs’ studies, including the International LQTS Registry, the North American ARVD Registry, MADIT II, and MADIT-CRT, and large clinical trials testing the clinical effectiveness and safety of implantable cardiac defibrillators and resynchronization devices. Additionally, he served as Principal Investigator or co-Principal Investigator on numerous NIH- and corporate-funded studies focused on risk stratification of cardiac death and, clinical usefulness and prognostic significance of ECG parameters.
“Given the overburdened state of our health system, we cannot afford to have patients receive expensive therapies like ICDs and CRT-Ds that are not beneficial. Specifically, we need to more accurately identify those patients – specifically those at highest risk for cardiac and heart failure morbidity and mortality -- who will benefit from interventions that can reduce the enormous expenditures associated with heart failure decompensation, most significantly hospital/ICU admissions. Early intervention targeting those at highest risk for future decompensation may well help avoid costly re-admissions later,” Dr. Zareba stated.
To underscore the magnitude of the problem and its impact on the U.S. healthcare system, Dr. Zareba referenced the following statistics
- According to the American Heart Association, heart failure affects nearly 5.7 million Americans of all ages and is responsible for more hospitalizations than all forms of cancer combined. It is the leading cause for hospitalization among Medicare patients.
- Heart failure is the fastest-growing clinical cardiac disease entity in the U.S., affecting 2% of the population.
- Each year, 550,000 new cases of heart failure are diagnosed and 300,000 deaths are caused by heart failure.
- Nearly 2% of all hospital admissions in the U.S. are for decompensated heart failure; heart failure is the most frequent cause of hospitalization in patients older than 65 years, with an annual incidence of 10 per 1,000.
- The average duration of hospitalization for heart failure is 6 days.
Dr. Zareba explained that heart failure patients typically experience an insidious downward spiral. Their heart and overall physiology -- cardiac shape and function, and neurohormonal balance -- undergo “negative remodeling” resulting in more severe heart failure and eventually death. Initially, despite these negative changes having already begun, heart failure patients may appear relatively stable.
“Being able to identify those heart failure patients entering the downward spiral, especially in the early stages when interventions may be far more likely to succeed – be they lifestyle/nutrition, pharmacological, or device/procedural – has the potential to result in improved quality of life and vast cost savings for our overburdened healthcare system. The results of ‘Prognostic Significance of Point Correlation Dimension Algorithm (PD2i) in Chronic Heart Failure’ study are of major importance for those involved in the search to identify a means of enhancing risk stratification of heart failure patients eligible for ICD or CRT-D, ” Dr. Zareba continued.
The goal of “Prognostic Significance of Point Correlation Dimension Algorithm (PD2i) in Chronic Heart Failure” was to evaluate the ability of Vicor’s PD2i® nonlinear algorithm, to predict cardiac events in the 537 chronic heart failure patients enrolled in the MUSIC Trial; MUSIC Trial participants were followed for an average period of 44 months. The conclusion of the University of Rochester researchers who conducted the study is that the PD2i® nonlinear algorithm and software is predictive of total mortality, cardiac death, and heart failure death in patients with left ventricular ejection fraction of less than or equal to 35%. With a hazard ratio of 2.34 and a P value of 0.023 for congestive heart failure mortality, a hazard ratio of 1.89 and a p value of .013 for cardiac mortality and a hazard ration of 1.95 and a p value of .004 for total mortality, the study results are highly statistically significant and demonstrated the ability of the PD2i Analyzer™ to identify those patients at an elevated risk of total mortality, cardiac mortality and congestive heart failure death.
The results of this study appeared in a poster presentation -- "Prognostic Significance of PD2i, Novel Risk Marker in Heart Failure Patients” – at the American College of Cardiology 60th Annual Scientific Session on April 4, 2011
“These results are of major importance for risk stratifying heart failure patients who are eligible for therapy with an implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy with defibrillator (CRT-D). Testing heart failure patients using the PD2i® should enhance risk stratification and motivate physicians to implant these devices in ICD/CRT-D eligible patients with abnormal PD2i® test results,” Dr. Zareba concluded.
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