Mandatory medical device diagnostics.
- Ankle-brachial index* (ABI; examination method that can describe the risk for cardiovascular disease) – for suspected lower extremity occlusive disease (LEAD, lower extremities arterial disease) [see table below].
- Color-coded duplex sonography (FKDS; ultrasound examination: combination of a sonographic cross-sectional image (B-scan) and the Doppler sonography method; imaging method in medicine that can dynamically depict fluid flows (especially blood flow)) – for clarification of the aorta and its branches, as well as the iliac and leg arteries, resp. to detect plaques (patchy deposits in the vascular endothelium), thrombi (blood clots) and stenosis (narrowing) (suitable test to detect pAVD. (Evidence class 1)) [alternative to ABI]
* For screening, measurement of ankle-brachial index (systolic ankle artery pressure/systolic brachial artery pressure quotient) is recommended. Optional medical device diagnostics-depending on the results of the history, physical examination, laboratory diagnostics, and obligatory medical device diagnostics-for differential diagnosis.
- Intraarterial angiography (imaging of blood vessels by contrast medium in an X-ray examination) or intraarterial digital subtraction angiography (DSA; procedure for isolated imaging of vessels: images of the body region to be examined are first obtained without and then with a contrast medium. The resulting images are further processed by a computer, whereby the first images without contrast medium are subtracted from the subsequent images). – For the precise localization of suspected stenoses (narrowings); Disadvantage: contrast agent exposure (due tokidney damage in pAVK patients) [gold standard in terms of accuracy and clarity of vascular imaging].
- Magnetic resonance angiography (MR angiography) – imaging of the arteries after contrast agent administration with the help of magnetic resonance imaging (MRI; computer-assisted cross-sectional imaging method (by means of magnetic fields, that is, without X-rays)) – for the precise localization of suspected stenoses; disadvantage: no simultaneous intervention possible.
- Computed tomographic angiography (CTA): examiner-independent and valid examination method with high sensitivity and specificity in vascular diseases; disadvantages: radiation exposure, iodine-containing contrast medium administration and the overestimation of the degree of stenosis in thin-caliber vessels with calcifying stenoses.
- Transcutaneous oxygen measurement (determination of transcutaneous partial pressure of oxygen, tcPO2) – to estimate the risk of amputation in critical ischemia (reduced blood flow).
- TcPO2 value < 30 mmHg in the supine patient (depending on influencing variables such as skin condition, anemia, oxygen saturation (SpO2) of the blood, etc.): critical ischemia.
- TcPO2< 40 mmHg is associated with an increased complication rate after amputation (tcPO2 < 10 mmHg → risk of amputation 70%).
- Treadmill test – for atypical pAVK complaints.
Assessment of ABI indices
| Ankle-brachial index (ABI) | Clinical significance |
| > 1,3 | False high values (suspicion of mediasclerosis)* . |
| 0,9 | normal |
| 0,75-0,9 | mild pAVK |
| 0,5- ≤ 0,75 | moderate-severe pAVK |
| < 0,5 | Critical limb ischemia |
An ABI value of <0.9 is considered demonstrative of the presence of relevant pAVD (evidence class 1).
* Toe pressure measurement (TBI): because mediasclerosis affects the digital arteries less than the transtibial arteries, recording the big toe pressure at values ≤ 30 mmHg provides additional evidence of the presence of critical ischemia (reduced blood flow). Toe pressure is approximately 30 mmHg below systolic ankle pressure and the pathological toe-brachial index is 0.7 or less.
