The Obstetrics and Gynecology Devices Panel of the Medical Devices Advisory Committee met on June 23, 2005, in an open session.
The panel discussed the pre-market approval application (PMA P020001) from Neoventa Medical AB (Göteborg, Sweden) for the STAN® S31 Fetal Heart Monitoring System (STAN® System). The proposed indication for use for the STAN® System is for use in pregnancies at term (>36 completed gestational weeks) to improve the assessment of the fetal condition during labor and as an adjunct to standard fetal heart monitoring.
The STAN® S31 is an intrapartum monitoring system with fetal ECG (FECG) analysis capabilities. Previous fetal monitoring devices have collected FECG information, using a fetal spiral electrode. It is from this signal that the fetal heart rate (FHR) is derived from the R wave. The STAN® System uses the data acquired by the scalp electrode by deriving the T/QRS amplitude and ST segment slope and comparing the most recent values to baseline values collected during the first 20 minutes of data collection. As output, it provides automatic identification of three types of ST events on the monitor and tracing: episodic T/QRS rise, baseline T/QRS rise, and 3 grades of biphasic ST.
The PMA for the STAN® System was initially reviewed in 2002. The pivotal study supporting its safety and effectiveness was a multi-center randomized controlled study of 4966 subjects conducted in Sweden. The panel considered the PMA in April 2002 and expressed concerns about differences between Sweden and the U.S. for labor management practices and underlying medical terminology. When FDA found the PMA “not approvable,” Neoventa was asked to conduct bridging studies in the United States (U.S.) to show that clinicians here could learn the STAN® System technology and apply it in a clinically appropriate way. Since the time of that meeting, Neoventa designed and conducted two “bridging” studies.
The panel considered the submission of these two “bridging” studies, which looked at the use of STAN® System by clinicians in the United States. The first study, the Education study, was intended to evaluate the training of U.S. clinicians. This was a “virtual” clinical study where 13 U.S. clinicians read 51 pre-recorded cases three separate times: before training (FHR only), after training (FHR only), and after training (FHR + ST). Success was based on agreement of the U.S. raters with 7 Swedish experts and among themselves on whether and when to intervene. The second study, the Clinical Use study, involved actual patient management by U.S. clinicians. In this study, the STAN® System was used for the management of 530 women in labor at six U.S. sites. These same cases were evaluated by a panel of STAN® experts. Management decisions made by U.S. investigators were compared to recommendations of the expert panel. Three endpoints were compared: negative predictive value, positive percent agreement, and negative percent agreement.
The panel voted 9-0 recommending approval of the PMA for the STAN® S31 Fetal Heart Monitoring System, subject to the following conditions:
- changes to labeling, especially the indications/usage statement to reflect that it should be used as an adjunct to the assessment of non-reassuring fetal heart rate tracings
- development of complete set of education/training tools, including a required training/credentialing plan that can be adopted for different hospital settings (e.g., community vs academic, urban vs rural)
- above package of education/training materials must be a deliverable with each monitor
- postmarket study or surveillance program to evaluate the impact of this technology in the market setting on the following endpoints:
- cesarean delivery (compared to c-section rates before use of STAN® technology)
- fetal acidemia, as evidenced by umbilical cord arterial pH at delivery
- Apgar scores
- neonatal encephalopathy
- why the clinician used the STAN® device
- usage rate (i.e., for what percent of labors did institution use the STAN® monitor)
- compliance with/effectiveness of training program
Contact: Michael T. Bailey, Ph.D., Executive Secretary, 301-594-1180, x130.
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