Good reading.
If Guardwire gets CE with 22 patients, we can easily get it with 40 patients. That answered my questions earlier.
Guardwire below is class III high risk...I seriously doubt AC5 is in the same category. The don't need hundreds (800 !!) of patients to get US approval for either external or internal.
The U.S. approval process for medical devices is very different, especially in terms of the scope and size of clinical trials required for high-risk devices. To receive approval to market a device in the EU, the manufacturer must demonstrate that the device is safe and that it performs in a manner consistent with the manufacturer's intended use. To receive approval to market a class III high-risk (and some class II) device in the United States, the manufacturer must demonstrate that the device is reasonably safe and effective. This typically requires a prospective, randomized controlled, adequately powered clinical trial involving hundreds of patients.
This significant difference is illustrated by the example of distal protection systems used in interventional cardiology. The first such system to be developed was a specialized coronary guide wire with an expandable balloon at its tip (GuardWire from Percusurge, Inc., which was later acquired by Medtronic). During a coronary angioplasty or stenting procedure, the device is inserted via femoral arterial access and the balloon is inflated distal to the lesion. After the balloon is expanded, the lesion is treated. The purpose of the device is to block any dislodged arterial debris from embolizing. After the lesion is treated, any debris is evacuated by aspiration and the GuardWire is removed.
In the EU, the GuardWire device was awarded CE marking by demonstrating safety and performance (i.e., the ability to aspirate material during the stenting procedure) in a 22-patient, single arm study.6 In the United States, this device was designated Class II. To demonstrate safety and effectiveness (defined as the ability to reduce complications associated with stenting of saphenous vein grafts) the FDA required an 800-patient, multicenter, randomized trial comparing distal protection to usual care (no protection).7
