Frequently Asked Questions

The intended use of the CADScor®System is to record heart sounds, i.e. murmurs and vibration for calculation of a patient specific score, the CAD-score, indicating the risk of coronary stenosis, as an aid in cardiac analysis and diagnosis. We suggest using the CADScor®System as a first-line non-invasive diagnostic aid to rule-out CAD in patients suspected of stable CAD, to avoid further downstream testing and invasive diagnostic procedures. A patient with a low CAD-score (≤20) is highly unlikely to have CAD. A patient with an elevated CAD-score (>20) has an increased likelihood of disease and should be followed more closely or referred for further evaluation.

Patients with heart valves are not contraindicated. In Dan-NICAD, in a low number of patients with heart valve disease, higher CAD-scores were observed. Remarkably, this was only the case when the clinical risk factors were added, and not with the acoustic score only, indicating that patients with heart valve disease are diagnosed accurately. In case the artificial sound of the heart valves disturbs correct segmentation, the device would indicate this, but this has not been reported as a major issue.

Defining significant CAD as ≥50% luminal diameter reduction, the sensitivity to identify a patient with significant CAD is 87.5%. Specificity is 37.5%*. Under these conditions the test has a NPV of 96.2% in a 10.7% CAD prevalence population. Data has been calculated from the CADScor® clinical database using the latest implemented CADScor®System algorithm version.
*US-FDA revision 12.5

Sensitivity is the ability of a test to correctly classify an individual having a specific condition. Specificity is the ability of a test to correctly classify an individual not having a specific condition. Positive Predictive Value (PPV) is the percentage of patients with a positive test who have the condition. Negative Predictive Value (NPV) is the percentage of patients with a negative test who do not have the condition. Positive and NPVs are directly related to the prevalence of the condition in the population. Assuming all other factors remain constant, the PPV will increase with increasing prevalence; and NPV increases with decrease in prevalence.

No, the CADScor®System does not indicate the location of stenosis. We have demonstrated a correlation of the severity of CAD and the CAD-score. The more vessels show stenosis, the higher the CAD-score. (Winther S et al. Diagnostic performance of an acoustic-based system for coronary artery disease risk stratification. Heart (2018): 104, 928-935 and Schmidt SE et al. Coronary artery disease risk reclassification by a new acoustic-based score. Int J Cardiovasc Imaging (2019) 35: 2019–2028)

Yes, the Dan-NICAD study showed there was no correlation between the CAD-score and the anatomical location of the stenosis, indicating similar diagnostic accuracy in detecting stenosis in the four major coronary arteries (Winther S et al. Diagnostic performance of an acoustic-based system for coronary artery disease risk stratification. Heart (2018): 104, 928-935)

Yes, you can use the CADScor®System in suspected CAD patients with calcified arteries. We know that the higher the CACS (coronary artery calcium score), the higher the CAD-Score.

A total occlusion does not generate heart sounds from turbulent flow. Most patients with total occlusion do not have an isolated total occlusion but a generalized CAD. Accordingly, heart sounds generated from the ischemic heart will contribute to the CAD-score. In the majority of cases, patients with total occlusions will have a CAD-score >20 (elevated risk). (see eg. Winther S et al. Diagnosing coronary artery disease by sound analysis from coronary stenosis induced turbulent blood flow: diagnostic performance in patients with stable angina pectoris. Int J Cardiovasc Imaging (2016) 32:235–245.)

We do not have specific data on plaque composition. A plaque, irrespective of its nature, results in a change of coronary flow and changes the acoustic information in such a way that it can be distinguished form a healthy artery.

There are no specific instructions on breathing prior to the breathing pause in the user manual. It is recommended not to do any excessive inhalation or exhalation prior to holding the breath.

Schmidt et al showed that the CAD-score had similar sensitivity in groups according to BMI (<20, 20-<25, 25-<30, ≥30) but there was a trend toward lower specificity with increasing BMI (Schmidt SE et al. Coronary artery disease risk reclassification by a new acoustic-based score. Int J Cardiovasc Imaging (2019) 35: 2019–2028.)

The CADScor®System is approved in Europe (CE mark 2015) and has been marketed since Q2 2017. FDA Approval since November 2020.

Currently (beginning of 2022) the CADScor®System is used in Denmark, Sweden, Finland, Germany, Austria, Switzerland, Luxemburg, UK and USA.

The CADScor®System is a Class IIa device. The patch is a Class I device.

In section 11 of the CADScor®System user manual.

The system will indicate if the battery is low. The battery drain is significant during qualifications. Charging it for 15 minutes is sufficient for a couple of recordings, 30 minutes for approximately 10 recordings.

Guiding the patient during the CAD-score evaluation is essential. Two parts of each recording loop exists, one in which the patient is breathing normally and one in which the patient will hold his/her breath. During the breath holding period no talking (or noisy behavior) can take place.

No. The patch contains a specific code that is registered and marks the patch as used.

The used patches can be disposed together with other standard clinical waste.

In 2015 a study from Winther et al. (Denmark), with 228 patients, led to the approval of the device with algorithm v2 Europe. The study was published in 2016 with a diagnostic performance for diagnosing >50% stenosis with 90% sensitivity and 92% NPV (prevalence 28%). Dan-NICAD (Denmark), with 1675 patients, was published in 2017 and was the basis for the evolution of algorithm v2 towards algorithm v3.1 which is performing in the commercial device. The Dan-NICAD population showed a diagnostic performance of 81% sensitivity and 96% NPV for diagnosing >50% stenosis (prevalence 9.3%).

The combined database population (prevalence 10%) performs with 88.7% sensitivity and 97% NPV. 2016 and 2017 VALIDATE (Germany) were performed to gain data outside the intended population (high-prevalence population) to contribute to the evolution of the algorithm. Currently (beginning of 2022), all Dan-NICAD II patients are enrolled, follow-up period ongoing. The CADScor®System Algorithm v3.1 database performance is based on 2245 patients (prevalence 10%). Eight acoustic properties covering four aspects of the heart sound are assessed and subsequently combined with clinical risk factors (age, gender, Hypertension), using logistic regression into a CAD-score. Examples of the acoustic properties are the amplitude of the fourth heart sound, the characteristics of the systolic and mid-diastolic heart sound and the frequency distribution of the second heart sound. All those sounds have previously described to be predictive of the presence of CAD.

Yes, there are several clinical studies ongoing

• VALIDATE - Prospective, consecutive, blinded, clinical investigation validating the performance of the CADScor®System against invasive coronary angiography in subjects with symptoms of stable CAD referred for invasive coronary angiography. Ended,
• Dan-NICAD II - Danish study of Non-Invasive diagnostic testing in Coronary Artery Disease (CAD) II - Patientinclusion ended, Follow-Up on due.
• AKUSTIK – German study. Clinical utility of the acoustic detection of coronary stenosis as early rule-out system – a blinded comparison to standard care.
• FILTER-SCAD - A prospective, randomized, controlled, parallel-group, multicentre trial to examine the cost-effectiveness and safety of adding the CADScor®System as a rule-out test in patients referred with symptoms suggestive of stable coronary artery disease (CAD) 
• SCG-HF – (Seismo) – Exploratory study – New indication -Identification of heart failure patients by seismocardiography; a comparison with echocardiography and brain natriuretic peptide.