Case Study
The Small and Mighty LVAD Micro-Impeller
Overview:
Client: Cardiovascular Systems, Inc. (now part of Abbott)
Industry: Cardiovascular Medical Devices
Project: LVAD Micro-Impeller Feasibility Program
Time to Functional Prototype: Approximately 6 Months
60,000 RPM. Five Millimeters. Six Months.
Some engineering challenges demand more than experience—they demand unconventional thinking.
A leading cardiovascular medical device company approached Caztek with a confidential challenge unlike anything we'd tackled before: prove that an ultra-miniature Left Ventricular Assist Device (LVAD) was technically feasible inside a 4–5 mm package.
There would be no public announcements. No lengthy development timeline. No room for failure.
The objective was ambitious: develop a micro-impeller capable of operating at 60,000-80,000 RPM, deliver safe, hemocompatible blood flow, and validate the concept before committing to a larger development program. Exactly the type of challenge that energizes the Caztek team.
Working under strict confidentiality, our engineers assembled a cross-disciplinary "skunkworks" team, pulling ideas from cardiovascular devices, implantables, precision machining, micro-mechanisms, and even traditional watchmaking. Ruby jewel bearings—technology normally found inside precision timepieces—became a critical part of the solution, allowing an incredibly small shaft to spin at extreme speeds while maintaining precision and minimizing friction.
Rapid design-build-test cycles compressed what could have been a multi-year feasibility effort into approximately six months, delivering a functional prototype that demonstrated the concept and helped launch the next phase of development.
A Confidential Program Built to Move Fast
Although Cardiovascular Systems was widely recognized for their atherectomy technologies, leadership was exploring entirely new cardiovascular therapies.
Because the company was publicly traded, early feasibility work needed to remain completely confidential. Rather than committing internal resources before technical risk had been retired, they partnered with Caztek to execute the program quietly, rapidly, and independently.
The assignment wasn't simply to design another medical device.
It was to determine whether something many believed impossible could actually be engineered.
A Five-Gallon Bucket Started It All
Long before the program became an LVAD development effort, it began with a friendly engineering competition.
Our client challenged another veteran medical device engineer to an informal "pump-off" at an upcoming industry conference.
The goal? Build an impeller capable of throwing water higher from a five-gallon bucket.
Simple.
We quietly joined the effort behind the scenes, designed and machined a prototype in less than a week, and tested it exactly the way engineers often do—with whatever equipment was available.
When power was applied, the water plume climbed. We won.
That simple experiment demonstrated what mattered most: rapid engineering, creative problem-solving, and the ability to move faster than anyone expected.
It also earned Caztek the opportunity to tackle the confidential LVAD program.
Engineering at the Edge of What's Possible
Designing something this small changes everything.
At a diameter of only 4–5 millimeters, every micron matters.
Bearing alignment.
Surface finish.
Impeller geometry.
Blade clearance.
Even the smallest dimensional variation could dramatically affect both hydraulic performance and blood compatibility. Generating flow wasn't enough.
The system had to protect red blood cells from excessive shear stress, turbulence, and cavitation—all major contributors to hemolysis. This required careful CFD analysis, precision machining, and relentless iteration.
Engineering Highlights
Miniaturization Without Compromise
The complete pump architecture—including the impeller, bearings, shaft, and housing—was engineered inside an envelope only 4-5 mm in diameter, while remaining suitable for insertion through the femoral artery.
Blood-Safe Performance
Rather than simply maximizing flow, we optimized blade geometry, clearances, residence time, and pressure characteristics to achieve high hydraulic efficiency while minimizing blood trauma.
Borrowing from Watchmaking
Sometimes breakthrough engineering comes from unexpected places.
Instead of conventional miniature bearings, Caztek incorporated synthetic ruby jewel bearings, borrowing technology commonly found inside precision mechanical watches.
The result was exceptional concentricity, extremely low friction, and stable operation at rotational speeds approaching 80,000 RPM.
Cross-industry thinking like this is part of what makes Caztek different.
Rapid Engineering
Additive manufacturing allowed us to evaluate dozens of concepts in days rather than weeks.
Once performance converged, precision-machined components replaced printed parts, delivering the surface finish, concentricity, and tolerances required for high-speed operation.
Every iteration brought measurable improvements.
Six Months Instead of Years
Operating under strict confidentiality, our engineers maintained a rapid cadence of concept development, analysis, machining, testing, and refinement.
The result was a fully functional feasibility prototype in approximately six months—compressing what often becomes a multi-year development effort.
Quiet Innovation. Meaningful Impact.
The prototype successfully demonstrated technical feasibility, giving the client's leadership confidence to move the program forward.
More importantly, it validated the underlying engineering principles and laid the foundation for continued development.
Like many Caztek programs, the work happened quietly, behind the scenes, helping our client reduce technical risk, accelerate innovation, and make informed decisions with confidence.
Why Caztek
The toughest engineering problems rarely have textbook solutions.
That's why Caztek builds small, highly collaborative teams capable of moving quickly, challenging assumptions, and borrowing ideas from industries others never think to combine. Whether we're developing next-generation cardiovascular devices, aerospace systems, or advanced automation, our focus remains the same: accelerate innovation, eliminate technical risk, and deliver production-ready engineering faster than conventional development models allow.