The Medicines and Healthcare products Regulatory Agency (MHRA) of the United Kingdom (UK) has issued a medical device safety alert concerning bi-leaflet mechanical heart valves.
MHRA is aware of 5 incidents worldwide over the last 15 years where mechanical bi-leaflet prosthetic valves of different models are believed to have been implanted inverted because they were put on their holder upside-down. The actual figure is likely to be higher as there is under-reporting of these events.
The probability of this error remains very low relative to the millions of valves implanted during this time, but the harm that can result is extreme, sometimes fatal.
Despite warnings in the manufacturers' instructions for use (IFU) not to remount a valve on its holder, this has not entirely prevented this practice, with tragic consequences. Although the risk of inverted valve implantation cannot be completely eliminated, the holder itself can be designed to be unidirectional, preventing inverted mounting. One manufacturer's (St. Jude Medical, now Abbott) holder design is currently unidirectional, thereby also eliminating the risk of inversion on the holder during valve assembly.
As a consequence of the recent UK incident, MHRA has acquired agreement from the other 3 manufacturers of mechanical heart valves (Liva Nova, Medtronic, On-X Life Technologies) to redesign their holders to be unidirectional.
These undertakings involve long-term design projects, including thorough risk/benefit assessment and regulatory approval. As a result, valves mounted on unidirectional holders are unlikely to become available in the UK for up to a year or more, depending on the manufacturer.
Until all manufacturers have made these changes, it is important that all clinical personnel handling mechanical heart valves are aware of the serious risk associated with inversion of the valve on its holder.
For details, please refer to the MHRA website:
https://www.gov.uk/drug-device-alerts/replacement-bileaflet-mechanical-heart-valves-risk-of-inverted-implantation
If you are in possession of the affected products, please contact your supplier for necessary actions.
Posted on 1 September 2017