Value of quantitative photoplethysmography for functional vascular diagnostics. Current status and prospects

The paper presents recent advances in photoplethysmography (PPG) and the role played by PPG in the noninvasive diagnostics of venous and arterial disease. The technical principles of the new self-calibrating photoplethysmographs are explained. These units allow a quantitative evaluation of all measurement data (e.g. time values, amplitudes, flow rates, blood volume kinetics) and hence a precise analysis of both venous and arterial hemodynamics. In combination with appropriate tests (muscle pump test, vein occlusion test, noninvasive venous pressure test, arterial pulse and pressure test), they are suitable for diagnosing and assessing the severity of vascular disease and monitoring its course and the efficacy of therapy. Now that PPG has gained worldwide acceptance as a routine diagnostic technique for venous disease, its spectrum should be expanded to the arterial side as well.