Tips for Users — Optimizing Your Setup for Accurate Results
Small Adjustments - Big Impact in Vascular Flow Simulations
In previous articles of our Tech series, we’ve covered the core fluid dynamic principles that shape pulse duplicating pump systems, the role of compliance, how flow and pressure interact, and the importance of calibration. Now, in this article, we turn to you — the user.
Even with the best pump and most advanced vascular models, an improperly configured setup can skew your results. This article offers practical tips to help you optimize your simulation system for more realistic, reproducible, and physiologically accurate outcomes.
1. Minimize Pressure Drop: Tubing Selection Matters
What to avoid:
Long or narrow tubing increases resistance, causing significant pressure loss before the fluid even reaches your vascular model.
What to do instead:
Use hoses with a large inner diameter (≥10 mm) for high-volume flows.
Keep the length as short as possible, especially between the pump outlet and the model inlet.
Avoid sharp bends and Y-connectors unless absolutely necessary.
Why it matters:
The longer and narrower the tubing, the more pressure is lost. That makes it harder to achieve physiological values inside your model, even if your pump is working perfectly.
2. Clamp Down on Leaks and Air Bubbles
What to avoid:
Unsealed connections or unnoticed micro-leaks introduce air — and that ruins pressure transmission and waveform quality.
What to do instead:
Always use hose clamps or Luer lock fittings where possible.
Prime the system carefully and check for trapped air in bends, valves, or model chambers.
Use a degassing system if needed.
Why it matters:
Air compresses — unlike fluid — and this distorts pressure and dampens your pulse wave. Even small bubbles can corrupt your data.
3. Choose the Right Compliance for Your Goals
What to avoid:
Using either too stiff or too soft vascular models or tubing for your intended application.
What to do instead:
Match compliance to the vessel being simulated. Use softer silicone for arteries, and stiffer materials for calcified models.
If a more rigid model is required (e.g. for stent deployment), compensate by tuning pump parameters or reducing flow volume.
Why it matters:
Compliance controls how the vessel expands and contracts. That expansion affects both pressure and flow — critical in training and testing scenarios.
4. Match Stroke Volume to Model Scale
What to avoid:
Using full heart-equivalent stroke volumes (e.g. 70 ml) for models representing only a segment of the vascular system.
What to do instead:
Scale stroke volume to match the region of interest.
For a model of the aortic arch, 15–30 ml might be enough.
Use blood distribution charts to estimate realistic flow needs.
Why it matters:
Too much stroke volume in a small model will generate unrealistically high velocities, distorted pressure curves, and turbulent flow.
5. Consider Sensor Placement and Calibration
What to avoid:
Assuming that sensor readings near the pump match those inside the model.
What to do instead:
Place pressure sensors as close as possible to your region of interest.
Calibrate sensors using a reference gauge, ideally at multiple points.
Use software correction factors if needed.
Why it matters:
As we’ve shown in a previous article, pressure isn’t the same everywhere — and calibration helps ensure your numbers actually reflect physiological reality.
6. Keep It Simple - When a Systolic-Only Flow Is Good Enough
What to avoid:
Don’t overcomplicate your simulation setup with components you may not need. Many users assume a full arterial pressure waveform is always required, but that’s not true for all scenarios. Adding compliance chambers, back-pressure modules, or waveform controllers too early can increase setup time, cost, and instability - without meaningful benefit.
What to do instead:
Use systolic-only output for simulations that do not rely on the diastolic phase. These include:
Venous flow simulations
Educational or anatomical demonstration models (e.g. our Angiotrainer)
Device testing in isolated vascular segments (e.g., renal or femoral arteries)
Early-stage flow visualization setups
These systems benefit from a simple, repeatable pulse that represents cardiac ejection, without needing recoil or elastic decay.
Why it matters:
By keeping your setup simple, you reduce the number of failure points, streamline your experiment or training session, and improve the reliability of your data. It also makes troubleshooting and transport easier — which is a huge plus in mobile or multi-site environments.
7. How to Realize Diastolic Pressure When Your Pump Only Delivers Systolic Output
What to avoid:
Avoid assuming that your pump will automatically simulate realistic diastolic pressures just by setting the correct waveform or stroke volume. Most standard pumps — including piston, gear, or centrifugal types — only produce active systolic pressure. Without any additional system compliance, pressure will drop to zero after each pulse. This can lead to unrealistic flow, underpressurized distal sections, and ineffective training or testing conditions.
What to do instead:
If your setup requires a realistic arterial pressure curve with diastolic pressure retention, consider one of the following:
Add a compliance chamber
Simulates vascular elasticity and sustains pressure between pulses.Introduce an adjustable flow restriction (afterload)
Helps delay pressure decay and increases baseline pressure.Use static pre-pressurization
A reservoir with controlled pressure can provide a constant offset.Upgrade to a programmable or dual-phase pump
Allows real-time shaping of the entire waveform.
Each solution has trade-offs, but a compliance chamber offers the best combination of affordability, effectiveness, and simplicity for most simulation users.
Why it matters:
Diastolic pressure plays a critical role in coronary perfusion, valve closure, and overall vascular behavior. Incomplete waveforms can lead to misleading results, especially in device testing, valve training, or simulation of elastic arteries like the aorta. If your model needs to replicate realistic hemodynamics, actively managing the diastolic phase is essential for credibility and performance.
Takeaway: Realism Comes from Details
Optimizing your setup isn’t about expensive upgrades — it’s about knowing where to look and what to adjust. Shorten tubing, eliminate leaks, match stroke volume and compliance, and validate your pressure readings.
By refining your setup, you transform your vascular simulation from a basic fluid loop into a realistic training or research environment.
Next time, we’ll take a broader look at the different pump technologies used in vascular simulation — from peristaltic and syringe pumps to centrifugal systems like the Flowbox. We’ll discuss the pros, cons, and ideal use cases of each system to help you choose the right one for your simulation needs.