Non-invasive estimation of coronary resistance and compliance: Prospective diagnostic study vs. angiography

Abstract

Background Early identification of coronary artery disease (CAD) remains challenging, particularly in patients who cannot undergo exercise-based or contrast-dependent diagnostic testing. We evaluated a non-invasive pulse wave-based device, Coronyzer (KH-3000), designed to derive resistance and compliance indices for early screening of CAD. Methods A prospective diagnostic accuracy study was conducted in 94 patients with suspected angina who underwent coronary angiography (CAG). Significant CAD was defined as >= 50% diameter stenosis. Diagnostic performance was assessed using pre-specified thresholds for resistance (R) and compliance (C). An independent retrospective validation study was performed in 136 patients who underwent CAG and computed tomography coronary angiography (CTCA). Diagnostic performance was evaluated using predefined OR and AND decision rules (R > 1.24 and/or C < 0.8). Results In the prospective cohort, sensitivity and specificity were 81% and 89%, respectively. In the validation cohort, the OR rule demonstrated high sensitivity (0.77) with lower specificity (0.41), whereas the AND rule showed lower sensitivity (0.53) but high specificity (0.78). Receiver operating characteristic (ROC) analysis demonstrated moderate overall diagnostic accuracy (area under the curve (AUC) = 0.67). Conclusions Coronyzer demonstrated clinically meaningful diagnostic performance as a non-invasive screening and risk stratification tool for coronary artery disease. By avoiding radiation exposure, contrast agents, and exercise requirements, the device may support early clinical triage and referral for further diagnostic evaluation, particularly in patient populations for whom conventional testing is limited.