BME100 f2017:Group7 W1030 L2

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BME 100 Fall 2017 Home
Lab Write-Up 1 | Lab Write-Up 2 | Lab Write-Up 3
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Sarah Brady
River Rodriquez
Kayla Culhane
Adriane Cana
Sevy Perez


Device Image and Description

Atherectomy Device

Our prototype is a handheld, self-injectable atherectomy plaque removal device. It is designed to mimic the lenticels on a mangrove tree that act as raised pores and open to move external 'gas' or liquid internally. The many raised pores on the surface of our device have holes in the center that open and close to attract soft plaque. Our device aims to decrease restenosis rates by more effectively and safely removing plaque than other atherectomy devices. It also removes the need for hospital surgical procedures, because the safer interior design will be housed in an external automated unit that resembles the design of a handheld insulin pump.

Technical and Clinical Feasibility

Technical Feasibility

The device will need a catheter (the standard arterial catheter) attached to a needle (20-gauge for adults, 22-gauge for children) specifically for insertion. To guide it, the device will need an automated guide wire that the patient will use to insert the device. A gel tip that is disposable made of some sort of silica gel will be used to make guiding the device much easier and a rubber or gel coating on the device itself will reduce the pain of the procedure. The device itself will be made of an iron alloy with a filtration system inside to capture different types of plaque. The filtration system will include mangrove-like pores that open and close, trapping the plaques inside.

Building the filtration system could become an issue because it has to be leveled properly so the less solid plaque does not escape the device through the solid’s filter. There also has to be a way that the calcium is broken down enough to be held inside of the device. We must find a way to open and close the filters just enough that the initial plaque is removed from the artery and held in the device while removing other remaining plaques.

Plaque could leak from the device, making the procedure completely obsolete. It may be difficult to build a filtration system that has pores that open and close on its own.

Clinical Feasibility

Based on the challenges indicated in the technical feasibility section, this would likely work in the clinic. Many atherectomy devices, from the rotablator to the SilverHawk, have already been approved for use in real human subjects. Our device builds on their design and actually is less invasive because it doesn’t break up the plaque through a ‘blade’ style. In this case, if we use a catheter design that already exists on the market, inserting our atherectomy device should be no more dangerous or difficult to manipulate than prior devices.

Clinical risks will be the same as those found with other atherectomy devices currently on the market. Risks include restenosis post-surgery, heart attacks, perforation.

There has been one clinical trial in the US that assessed the safety and efficacy of orbital atherectomy, which is a device currently on the market that most resembles ours. The trial evaluated safety and efficacy of OAS for severely calcified lesions. The study relied on data from 440 subjects using a Diamondback 360 Orbital Atherectomy System. The trial lasted for 12 months, testing the safety of the device post-procedure after the end of the time period. They trial found examined the occurrence of Cardiac death, myocardial infarction, or revascularization of the target vessel. They studied the safety and efficacy over 30 days and 12 month. For 30 days, they found 89.6% freedom from adverse cardiac events and 88.9% procedure success. They found 91.4% angiographic success in the same time period. For 12 months, they found 83.1% freedom from adverse cardiac events and provided no data for efficacy in this time period.

There were also two completed studies on carotid endarterectomy. The first conducted a trial to find the difference between routine carotid shunting or selective carotid shunting during Carotid endarterectomy. They did this to determine which was a safer option with less complications. They study was carried out from December 2006 to June 2009, which was about 2 years and 7 months. The overall perioperative complications found in routine shunt were 7 out of 98 and for selective shunt it was 8 out of 102. The second trial was conducted to compare cognitive function after carotid endarterectomy and stenting. The study started in April 2011 and ended in January 2014, which was approximately 2 years and 9 months. There were no study results posted.

There are currently no studies on a 'handheld' atherectomy device, so we would need to find more information about whether clinical trials would be necessary for that aspect of our design.

Technical Feasibility Score

2, This device is simple in theory to build since it is just a cylinder of iron with a filter in it. The major issue with the technical feasibility will be the filtration system, but with proper research it will be easy to make. The research will not cost much money from what we understand, however it may take a lot of time. The design is fairly straightforward as the interior is biomimetic and the exterior is similar to a handheld insulin pump. This can also be accomplished at a reasonable cost as the device is quite small.

Clinical Feasibility Score

2, There are multiple atherectomy devices on the market, yet only one clinical study that proved efficacy and safety. Thus, there is a clear path to clinical success for our device, as others such as SilverHawk from Medtronic have been successful in bypassing the clinical process. The one caveat is that because our device is handheld, it may require special expertise/research (though success is likely).

Market Analysis

Value Creation

The device will be a more effective and cheaper way to remove plaque from arteries. The 'lenticel' design, enclosed by a rubbery/gel exterior is less damaging to veins and more thoroughly removes plaque. It also relies on silicone and iron, which are relatively cheap to buy in bulk. We will design it to fit into an automated, handheld exterior that a patient can use on themselves. This will reduce the cost and discomfort for the patient immensely. This device will also reduce the need for stent implants for those with cardiovascular disease.

Manufacturing Cost


  • Surface Area of design: 196.35 mm^2
    • Cost of Iron: $0.2 per 100 grams
    • Cost of Silicone Gel: $0.1 per 100 grams
    • Cost per pound of iron: $90.782
    • Cost per pound of silicone gel: $45.3592
      • Total Cost: $136.1412/lb
  • Cost of a 3 mm wide by 20 inch iron wire: $5.138
  • Volume of the cylinder: 196.35mm^3
    • Cost to fill up cylinder: $2.56
  • Packaging: $1 per device

Total Cost (materials) per 1 device: $8.698 (about 9)

Quality Assurance

Outsourced Audit of Suppliers: $15 per device

Machinery and Equipment

Outsourced Jigs and Fixtures: $10 per device


Outsourced Machine Manufacture: $20 per device

Final Manufacture Price

About $54 per device

Overview of Cost Determination Steps:

The group used the cost per pound of each material to find out the total cost. The costs determined were $90.782 per pound of iron and $45.3592 per pound of silicone. The weight of a 3mm wide by 20 inch iron wire was .0566 pounds. This was multiplied by the cost per pound of iron to get $5.138. The volume of our cylinder was 196.35mm^3. The amount of silicone gel to fill up the cylinder would be $2.56. In total the materials cost would be $7.698. Additional costs per device were then also added.

Sales Price

The average sales price would be $54 multiplied by 5 (to account for desired profit margin), which would be $270.

Market Size

More than 15,800,000 people have known coronary artery disease, yet there are only about 3,000 to 4,000 vascular surgeons in the US. As such, in order to make this device viable, it needs to be purchased directly by patients (reimbursed by insurance) rather than doctors. This would involve designing it similarly to handheld diabetes monitors. It would then be an easily injectable, super safe procedure. We estimate that half of the afflicted population would seek this type of treatment, which is about 7,900,000 people. Our estimated market size at $270 per unit with 5% penetrance in a market of about 7,900,000 people would be $106,650,000.

Market Size Score

1, Because our market size is between 80M and 200M.

Fundability Discussion

Based on the six fundability criteria we have so far assigned a score to (Customer validation: 1, Market size (US only): 1, Competition: 1, IP Position: 1, Technical Feasibility: 2, Clinical feasibility: 2), our device should be funded. Though it seems to balance on the edge of viable/not viable, we would predict it to be a device that grows in popularity as the ease of use becomes wider known in the population. None of our scores were zero and our highest scores were in technical and clinical feasibility. When we assigned scores of 1 to competition and customer validation originally, we assumed that physicians would be the primary purchasers. Now, we have changed our assumption to a mostly novel product that can be used by patients at home. This would raise both of these scores, because there are currently no known handheld atherectomy devices on the market. This means reduced competition and potentially increased customer excitement. On the other hand, this might decrease our feasibility scores since there are clinical trials for atherectomy devices but not for handheld atherectomy devices. Overall, there is some traction in the marketplace and the possibility of decent monetary return on investment.