Depends on the type.
There are several "artificial" heart valves, each with different manufacturers.
Here in the US - surgical mechanical valves - mostly St. Jude.
surgical biologic valves - mostly Edwards Lifesciences.
percutaneous (stented) valve
- Edwards currently available in US, but other companies like Medtronic and St. Jude (and other small companies) have devices in trials or experimental phase.