The Ankle-Brachial Index (ABI) has been a standard diagnostic tool for Peripheral Arterial Disease (PAD) for decades. However, it has limitations—especially in patients with hypertension or advanced arterial calcification (medial sclerosis), where it can lead to misleading results.
An innovative alternative is the Pulse Wave Index (PWI™). This method provides a reliable assessment of blood circulation—independent of blood pressure fluctuations or stiffened arteries. But what exactly is PWI™, how does it work, and why is it a valuable addition to vascular diagnostics?
Why ABI Alone Is Not Always Reliable
The ABI is calculated by comparing blood pressure at the ankles and arms. A low ABI value indicates circulatory impairment and is a key indicator of PAD.
➤ However, there is a challenge: In patients with medial sclerosis (advanced arterial calcification, common in diabetic patients) or hypertension, the ABI may appear normal or even falsely elevated, despite the presence of circulatory disorders.
PWI™ – The Innovative Alternative to Traditional ABI Measurement
The Pulse Wave Index is a new, blood pressure-independent method for detecting circulatory disorders. Instead of relying on blood pressure measurements, PWI™ analyzes the propagation of pulse waves in the blood vessels.
How Does PWI™ Work?
- Measures pulse wave propagation and amplitude in the arteries.
- Unlike ABI, PWI™ is unaffected by blood pressure variations or medial sclerosis.
- Provides direct insights into vascular health, identifying PAD at an early stage by analyzing wave transit time and amplitudes.
Advantages of Puls Wave Index Over ABI:
- Blood pressure-independent measurement – unaffected by hypertension or arterial calcification.
- Early detection of PAD – even when ABI results appear normal or misleading.
- Fast, delegable application – ideal for routine clinical use.
According to a study by Mayr et al. (2019)*, PWI™ provides higher diagnostic accuracy than ABI:
“In our study, PWI™ outperformed both oABI and dABI. This result is not surprising, as PWI™ is strongly influenced by the time to peak of the volume curve. This parameter is highly sensitive to post-stenotic flow curves and is generally less affected by vascular wall properties such as medial sclerosis.”
Modern Vascular Diagnostics with PWI™ and AngE™ Systems
With AngE™ systems, PWI™ can be measured quickly, reliably, and operator-independently. The technology enables:
- Automatic calculation of the Pulse Wave Index for precise diagnostics.
- Combination with other vascular parameters such as ABI and TBI for comprehensive vascular analysis.
- Seamless integration into clinical practice with fast, painless examinations.
The PWI™ method is particularly valuable for high-risk patients with diabetes, hypertension, or ambiguous ABI results, offering a significant advantage in diagnosing vascular diseases.
PWI™ in Clinical Practice with AngE™ Systems
The AngE™ system enables fast and reliable PWI™ measurements, integrated into a comprehensive vascular diagnostics tool.
Key benefits for clinical application:
- Fully automated measurement – minimizes operator dependency.
- Quick screening in under 3 minutes – efficient and non-invasive.
- Delegable procedure – reduces the workload of healthcare professionals.
A study by Horstick et al. (2020)** highlights the need for additional screening criteria beyond ABI:
“Critical limb ischemia with subsequent foot ulcers and minor amputations often fall below ABI measurement thresholds. Since peripheral interventions increasingly target foot arteries, additional criteria that assess macro- and microcirculatory hemodynamic improvements are of the highest interest.”
Conclusion: PWI™ as a Future-Oriented Alternative in Vascular Diagnostics
While ABI remains a key component in vascular diagnostics, PWI™ provides a crucial complementary tool, especially in cases where traditional ABI measurements fall short.
Combining ABI, PWI™, and additional vascular parameters offers a more accurate and reliable assessment of vascular health, enabling earlier and more targeted treatment.
Interested in learning more about PWI™ and its clinical applications? Contact us for a consultation! You can also find more information in our Guide on PAD Screening.
*Mayr, Hirschl, Klein-Weigel, Girardi, Kundi; 2019, Diagnostic accuracy of ABI by Doppler versus Oscillometry, VASA – European Journal of Vascular Medicine – Full Text Download
**Horstick, Messner, Grundmann, Yalcin, Weisser, Espinola-Klein; 2020, TOPP: a simplified, more reliable, and faster assessment, AJP Heart – American Physiological Society – Full Text Download
