Circulation Heart Failure, a journal of the American Heart Association, recently published the results from a study concluding that ventilator efficiency is more accurate than the current listing criteria for heart transplantation in identifying patients likely to derive a survival benefit from such intervention. The study conclusions reinforce the science behind the Shape-HFTM Cardiopulmonary Exercise Testing system, which measures ventilation parameters including ventilatory efficiency.
(PRWEB) April 6, 2010 -- Circulation Heart Failure, a journal of the American Heart Association, recently published the results from a study concluding that ventilator efficiency (VE/VCO2 slope) is more accurate than the current listing criteria for heart transplantation in identifying patients likely to derive a survival benefit from such intervention. The study conclusions reinforce the science behind the Shape-HFTM Cardiopulmonary Exercise Testing system, which measures ventilation parameters including ventilatory efficiency.
“Cardiopulmonary exercise testing (CPX) has been used for many years to help doctors understand the severity and prognosis in patients with chronic heart failure,” says Dean MacCarter, Ph.D., vice president of clinical studies for Shape Medical Systems Inc. “Peak CPX testing can guide physicians in their clinical decision-making, but conducting CPX tests at such levels comes with its own set of problems such as maximal physical effort by the patient, specialized training, and interpretation challenges.”
“This recent study reinforces the accuracy and reliability of measuring the VE/CO2 slope, which is a core parameter measured by the Shape-HF,” says Clarence Johnson, Shape Medical Systems President. “Further Shape-HF ventilatory efficiency measurements add resolution to the New York Heart Failure Association classification system for heart failure by providing a full range of values that make the assessment more sensitive and specific.”
Ventilatory Efficiency and Heart Transplantation Study Results
A total of 663 chronic heart failure patients who underwent cardiopulmonary exercise testing were tracked for cardiac mortality and heart transplantation. Symptom-limited CPX testing was performed on all patients. Oxygen uptake (VO2), carbon dioxide production (VCO2) and minute ventilation (VE) were measured on a breath-by-breath basis. Peak VO2 was defined as the highest 20- to 30-second average achieved during exercise. Patients were evaluated for the occurrence of death or heart transplantation. Follow-up was right-censored at three years.
Results showed that using a VE/VCO2 slope threshold instead of the current exercise criteria would classify 39 more subjects as high-risk, correctly identifying 19 more patients who died during follow-up, and 16 others who underwent transplantation. VE/VCO2 slope provided significant discrimination between the three years survival of both high- and low-risk patients relative to post-transplant patients. Re-analysis of survival data using death or heart transplantation as endpoint showed similar results. (Ferreira A, Tabet J, Circ Heart Fail, online Feb 22, 2010)
Shape-HF™ Cardiopulmonary Exercise Testing System
The Shape-HF System is the first gas exchange testing device specifically designed for cardiology. It is FDA-approved, easy to use, easy on the patient, and provides clinically relevant data that is easy to understand, reproducible and immediately useful to a cardiologist. Shape-HF measures a patient’s functional capacity and quantifies the severity of dyspnea on exertion. The test takes 15 minutes and involves measuring ventilation parameters while the patient exercises on a treadmill at a very low intensity. The Shape test also quantifies the heart rate response to exercise to determine if it is appropriate and can unmask potential co-morbidities that may adversely affect heart failure prognosis or therapy response.
Shape-HF is the only device that objectively measures cardiopulmonary gas exchange easily and quickly without undue strain on the patient. It can be used in the office setting and provides real-time physiological assessment to help physicians elucidate the physiological underpinnings of dyspnea, objectively assess patient functional classification, monitor therapy response and progress, identify potential co-morbidities, and optimize CRT at exercise levels consistent with patient daily activity. Importantly, Shape-HF exercise testing is cost-effective and easy to use.
Shape Medical Systems Inc. is a privately held, St. Paul, Minnesota-based medical device company whose core technology lies in the development and commercialization of products for assessing heart/lung interaction and ventilation in chronic heart failure and other cardiopulmonary disease. Shape's clear mission is to develop products that increase the quality of patients' lives by helping doctors quantify shortness of breath, assess patient functional capacity, optimize drug, device and rehabilitation therapy, and monitor patient progress. Shape testing provides evidence based outcomes. Shape Medical Systems was founded in 2004 and received FDA market clearance for the Shape-HF Cardiopulmonary Testing System in April 2009. The Shape-HF System, testing protocols and applications are protected by patent 7,225,022 and other U.S. and foreign patents issued and pending.
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