As we begin a new year, it is appropriate to reflect back on all that happened in 2006.  This year, the number of BioZ^® ICG devices grew to over 5,000 and the number of ICG tests that have now been performed passed 5 million!  ICG technology continues to provide clinicians and their patients with reliable hemodynamic data that can make a difference in how cardiovascular medicine is delivered. 

Once again, there were abstracts on ICG at the annual meetings of the American College of Cardiology, Heart Failure Society of America, and American Heart Association.  A number of key researchers in hypertension and heart failure have begun new projects in 2006 using the BioZ.  In addition, several centers are studying potential new applications for ICG-derived hemodynamics including the screening of athletes for suspected hypertrophic cardiomyopathy, optimizing medications in trauma and/or shock, identification of hemodynamic abnormalities during hypertension of pregnancy, and assessing the hemodynamic changes in patients with sleep apnea.  Finally, I am pleased to report that as of today, over 800 subjects have undergone baseline BioZ testing for PREVENCION, a large, population-based study in Peru.  This long-term study will follow several thousand subjects and assess the hemodynamic predictors of cardiac events.

As you can see from the Bibliography posted at the clinical ICG website (www.impedancecardiography.com), there have been a number of articles published in peer-reviewed journals this past year on various aspects of the technology.  The most significant publications were the three multicenter trials: in heart failure (PREDICT), in hypertension (CONTROL) and in dyspnea in the emergency department (ED-IMPACT).  Full-text versions of these three studies are available for downloading at: www.cdic.com/cdclin30.html. Recently, a cost-effectiveness analysis of data from the CONTROL study was published, which demonstrated that ICG appears to be cost effective in both the short term and long term for use in patients with uncontrolled hypertension on therapy with 1 or more antihypertensive agents. These landmark studies are now part of the slide set used by the members of our Speakers Bureau.  The Speakers Bureau has had a busy year, sponsoring over 30 local and regional events in 2006.  

In 2007, enrollment will begin in PREVENT-HF, one of the largest randomized controlled trials ever conducted in device-guided management of heart failure.  PREVENT-HF will compare the results of using ICG-guided therapy to standard care with the primary endpoint of time to first heart failure hospitalization.  A total of 212 heart failure hospitalizations will be required to evaluate the primary endpoint, which is expected to require approximately 500 patients.  The study will be conducted in 35 experienced investigative centers in the United States, Canada, and the United Kingdom.  The principal investigator is Dr. Milton Packer (University of Texas, Southwestern) and the Executive Committee includes Drs. Clyde Yancy (Baylor-Dallas), William Abraham (The Ohio State University), Mandeep Mehra (University of Maryland), and Barry Massie (San Francisco VA Medical Center).

As always, it has been great to hear from the many physicians and nurses using ICG in their practices.  We welcome your questions and hope that you’ll think of us when you encounter interesting ICG-related cases.  You may send us comments or questions by email at bioznewsletter@cdic.com, or you may call me at 800-778-4825, extension 1200.  My email is ntreister@cdic.com. 

Please forward this newsletter to your colleagues and refer your friends to CardioDynamics so we can answer any questions they have on our BioZ ICG technology.

Warm regards and wishing you a happy and healthy 2007,

Neil W. Treister, MD, FACC

Medical Director

Last July, CardioDynamics announced an Original Equipment Manufacturer (OEM) agreement with Shenzhen Mindray Bio-medical Electronics Co, Ltd. (Mindray), the largest manufacturer of patient monitoring products in China.  Under the terms of the agreement, Mindray will integrate CardioDynamics’ BioZ technology into its patient monitoring products, and CardioDynamics will receive a licensing fee for each BioZ(R) ICG OEM kit purchased by Mindray.

Serial Monitoring

In a previous Newsletter, we presented the case of a 78-year-old woman with long-standing hypertension and a recent hospitalization for progressive dyspnea on exertion.  She was obese with COPD and had a normal ejection fraction on echocardiography.  When seen in the clinic, she was on the following medications:

o   furosemide 40 mg daily

o   enalapril 5 mg bid

o   KCL 20 meq daily

o   metoprolol extended release 100 mg daily

Prior ICG Interpretation and Implications: The low CI and higher SVRI were consistent with her dyspnea of cardiac origin, attributed to heart failure with preserved systolic function.  The low TFC was thought to be due to her obesity and COPD (fat and air are poor conductors and have an opposite effect than water on the overall baseline impedance from which TFC is derived), particularly as no prior value was available and she appeared, if anything, fluid overloaded.

The treatment suggested on the basis of these hemodynamic findings and her symptoms was the intensification of vasodilator therapy.

Current Interpretation:  The CI and SVRI have normalized with more effective vasodilation, in parallel with her improvement in exercise tolerance.  The trend downward of her TFC is further evidence that her “normal” value is below the reference range, reflecting her particular chest impedance.  Thus, this result helps establish a baseline TFC value that can be very helpful if she returns with signs or symptoms and unclear fluid status.  Remember, increased fat and air in the chest cavity act as “the opposite of fluid” and would be expected to raise the chest impedance (Z₀) and thus lower TFC (TFC = 1/Z₀).

By now, many of you have received your copy of the brand new Pocket Clinical Guide.  As the name implies, this handy clinical reference tool fits in your pocket and contains a large amount of practical information about how to use the ICG to manage patients with dyspnea, heart failure, or hypertension.  In the Guide, you’ll find a quick overview of ICG technology,  the most up-to-date algorithms for the disease states, and lists of commonly used cardiovascular medications.  Carry the Guide with you and use it when you perform a BioZ in your office or hospital.  If you do not have a copy of the Guide or need additional copies, contact your Territory Manager, Clinical Applications Specialist, or email Celine Peters at cpeters@cdic.com.

As you may know, CardioDynamics made a formal request in 2006 to the Centers for Medicare and Medicaid Services (CMS) to reconsider and expand coverage of ICG in patients with hypertension.  Despite support from a large number of ICG users, CMS chose to leave the current indications unchanged. 

Please send us your questions and comments regarding this Newsletter or any issues related to ICG. You may reach us at bioznewsletter@cdic.com.

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