New Advances Offer Hope for Treating Heart Failure
Monday March 1, 2004
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The American Heart Association approximates there are nearly 5 million Americans with HF and an estimated 550,000 are newly diagnosed every year.1 The "blessings" of longevity for a growing aging population and better survival rates of patients with cardiovascular disease boost the numbers of patients living with HF. Ultimately, they battle functional impairment, decreased quality of life, and five-year mortality rates as high as 50%.2 Research is getting to the heart of the matter and offering hope to prevent or halt symptoms at HF's various stages.
Dial-Up Hemodynamics
"We want to keep heart failure patients out of the hospital - to catch symptoms before they become worse," says Gregory Poulin, RN, MSN, APRN-BC, a nurse practitioner at the Texas Heart Institute's (THI) Heart Failure Center at St. Luke's Episcopal Hospital, Houston. Every hospitalization relates to patients' weakening hearts and poorer prognoses.
Medtronic's Chronicle, a battery-powered implantable hemodynamic monitor that is under study at THI, may help better manage patients with advanced HF signs and symptoms at home. The Chronicle captures critical physiologic information in real-time, before patients may feel any change, permitting healthcare providers to intervene.
In the cath lab, the pacemaker-sized Chronicle is implanted under the skin in the left or right upper-chest area with a single lead that is inserted into the right ventricular outflow track. It senses and collects intracardiac pressures, heart rate, and physical activity. Patients use a remote monitor that plugs into a telephone jack to send data to a secure Internet site. Healthcare providers can access the network at any time and review screens that present summary information from the latest download, trend information, and detailed records from specified times or problem episodes.
"If patients experience tachycardia, for example, they use a wand to wave over the Chronicle site on their chests that will record what's happening physiologically," Poulin says. Healthcare providers interpret data and adjust patients' medications as needed, eliminating the guessing game from hemodynamic monitoring.
Behind the Scenes Genes
"Angiogenesis, the growing of new blood vessels, sounds like sci-fi," says Andrea Bowers, RN, BSN, (pictured at left) clinical research coordinator at Beaumont Hospital in Royal Oak, MI. In reality, angiogenesis occurs in the healthy body for healing wounds and for restoring blood flow to tissues after injury or insult.
For patients who've been through the ringer of medications, angioplasty, and coronary artery bypass graft (CABG) surgery, with recurrent but stable angina, Beaumont Hospital offers treatment trials in the third, pre-FDA-approval phase of angiogenic gene therapy.
The research focuses on supplementing the heart with growth factor protein to stimulate collateral blood vessel growth. Researchers attach fibroblast growth factor 4 (FGF 4) to a vector, the adenovirus or common cold virus, and infuse it via femoral access through a strawlike catheter into the appropriate area of the heart. "Over a period of weeks to months, FGF 4 coaxes the body to grow new, miniblood vessels, like minibypasses," Bowers explains.
Although clinical research nurses don't know which study participants receive FGF 4, they see improvement. Patients with previously limited mobility walk on treadmills longer and with less difficulty or shortness of breath. "Patients who've previously tried standard treatments to no avail tell us they feel as if they've been given back their lives," Bowers says. "The hope is to improve patients' quality of life by controlling activity-limiting angina." Five years down the road, researchers may better understand angiogenesis' potential as an additional treatment option.
Pumps On
Patients with damaged hearts, who are too ill to undergo surgery, may benefit from the TandemHeart. This percutaneous ventricular assist device (pVAD) provides circulatory support for high-risk patients during angioplasty or stent insertion.
"We slip a catheter into the heart before the procedure, 'steal' blood from the left side of the heart's atrium and run it through the device and let it generate cardiac output, then return it to the ventricle," explains Bernie Mendiondo, RN, CNS, cardiac ICU nurse manager at Cedars-Sinai Medical Center, Los Angeles. "TandemHeart reduces the ventricle's workload during interventional procedures, unloading the heart by circulating blood on the outside so that we can safely work on the heart to restore circulation and then remove the pump."
This external, hockey puck-sized pump is inserted in the cardiac cath lab using local anesthesia, eliminating invasive surgery. Unlike the currently used intra-aortic balloon pump, TandemHeart may help maintain patients' blood circulation near normal levels, preserve the heart, limit damage, and extend the time window for revascularization. Despite the advantages, TandemHeart is approved only as a bridge during cardiac interventions for HF patients who are at high risk during cardiac procedures.
Gamma Zaps
Despite the success of balloon angioplasty to open blocked coronary arteries, narrowing, or restenosis, still occurs. Brachytherapy and drug-eluting stents battle for top billing as reducers of postcoronary intervention restenosis. Brachytherapy provides radiation to the area to prevent excessive cell reproduction that may cause restenosis. Drug-eluting stents, which are paper-thin mesh tubes, prop open newly unclogged arteries as they release drugs to delay the scar formation that naturally occurs during the healing process.
"The rate of restenosis is high especially in the smaller peripheral blood vessels in the leg, making brachytherapy a viable option for patients with quality-of-life-limiting claudication," says Nelleke Yarbrough, RN, BSN, CCRC, research coordinator, American Cardiovascular Research Institute, Interventional Cardiology Division, St. Joseph's Hospital, Atlanta. As part of a safety and efficacy trial at St. Joseph's, the Therasource Intravascular Brachytherapy System deploys a palladium-coated wire through the balloon catheter in study patients' superficial femoral or popliteal arteries. The procedure lasts for about five to 10 minutes.
"The aim is to prevent restenosis by delaying healing at the internal layers of arteries," Yarbrough says. "With coronary and peripheral arterial disease on the rise, brachytherapy for lower extremities should be available soon."
Lorraine Steefel, RN, MSN, CTN, is a senior staff writer for Nursing Spectrum.
*Name has been changed.
References
1. ACC/AHA Guidelines for the Evaluation and Management of Chronic Heart Failure in the Adult. American College of Cardiology and the American Heart Association. September 2001. Available at: www.acc.org/clinical/guidelines/failure/pdfs/hf_fulltext.pdf. Accessed December 15, 2003.
2. Shively M, Wilson I. Health-related quality of life outcomes in heart failure; a conceptual model. In: Moser D, Riegel B, editors. Improving Outcomes in Heart Failure. Gaithersburg, MD: Aspen; 2001.
Latest Staging Takes Aim at Heart Failure Prevention
Heart failure (HF) is the only major cardiovascular disease increasing in prevalence in the United States.1 The latest American College of Cardiology (ACC)/American Heart Association(AHA) classification system of HF aims to reduce these unacceptably high statistics. Where the traditional New York Heart Association (NYHA) functional classification system categorizes HF according to the
relationship between symptoms and activities that trigger them, the newer system emphasizes the evolution and progression of HF. It cautions healthcare providers to recognize people at risk early on and provide timely treatment of risk factors, instead of waiting for structural heart disease, with or without traditional HF symptoms, to develop.
ACA/AHA
HF Stage Description
A High risk of HF, no apparent structural heart abnormality
B Structural heart disorder but no symptoms
C Structural disorder and past or current HF symptoms
D End-stage disease, person requires specialized treatments
NYHA
Class I No limitation of physical activity. No shortness of breath, fatigue, or heart palpitations with ordinary physical activity.
Class II Slight limitation of physical activity. Shortness of breath, fatigue, or heart palpitations with ordinary physical activity, but patients are comfortable at rest.
Class III Marked limitation of activity. Shortness of breath, fatigue, or heart palpitations with less than ordinary physical activity, but patients are comfortable at rest.
Class IV Severe to complete limitation of activity. Shortness of breath, fatigue, or heart palpitations with any physical exertion and symptoms appear even at rest.
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