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Results of the Fluid Accumulation Status Trial (FAST)1

 
FAST study demonstrated OptiVol® was more accurate than daily weight monitoring in predicting worsening heart failure1

Fluid Accumulation Status Trial (FAST) n = 156 patients
The Fluid Accumulation Status Trial (FAST) study was a multicenter, prospective, double-blinded investigation of the clinical utility of a fluid index derived from intrathoracic impedance measurements (OptiVol).

Methods
• Each device recorded daily changes in intrathoracic impedance
• Daily impedance changes were used to calculate a reference impedance and a fluid index
• Subjects recorded daily weight in a diary
• Sensitivity was determined by the number of adjudicated heart failure events, including hospitalizations, emergency room visits, urgent care, or unscheduled office visits occurring within 30 days of a fluid index threshold crossing or an acute gain in weight, divided by the total number of adjudicated heart failure events.
• Unexplained detections were defined as threshold crossings or acute weight gains not associated with an HF event

Results
OptiVol sensitivity (76.4%) was significantly greater than weights (22.5%) for detecting worsening heart failure
OptiVol’s unexplained detection rate (1.9/pt/yr) was significantly lower than acute weight increases (4.3/pt/yr)
• Impedance measurements were performed on greater than 99% of the follow-up days versus 76% of days for weights

OptiVol Detected Three Times More Future HF Events than Weight Monitoring Alone
Data are Generalized Estimator Equation estimates (95% confidence interval)
* Fluid Index Threshold = 60 ohm-days
† Weight Threshold = 3 lbs. in one day or 5 lbs. in three days

Summary
OptiVol Fluid Status Monitoring was a more accurate predictor of worsening heart failure than daily weight monitoring in heart failure patients with implantable devices
• OptiVol data collection is not limited by patient adherence
OptiVol Fluid Status Monitoring should be considered for routine use in patients with implanted devices with this feature, but is not intended to replace assessments, which are part of standard clinical practice
• OptiVol Predicts Worsening Heart Failure 2,3

References
1 Abraham WT. Superior Performance of Intrathoracic Impedance-Derived Fluid Index versus Daily Weight Monitoring in Heart Failure patients. Results of the Fluid Accumulation Status Trial. Late Breaking Clinical Trials. HFSA Conference 2009.
2 Whellan DJ, Al-Khatib SM, Kloosterman EM, et al. Changes in intrathoracic fluid index predict subsequent adverse events: results of the multi-site program to access and review Trending INformation and Evaluate CoRrelation to Symptoms in Patients with Heart Failure (PARTNERS HF) Trial. J Card Fail. November 6, 2008;14(9):799.
3 Small RS, Wickemeyer W, Germany R, et al. Changes in intrathoracic impedance are associated with subsequent risk of hospitalizations for acute decompensated heart failure: clinical utility of implanted device monitoring without a patient alert. J Card Fail. August 2009;15(6):475-481.