Apparatus for diagnosing lesion severity, and method therefor

Apparatus for diagnosing lesion severity of a lesion in an arterial lumen supplying blood to a muscle in its non-hyperemic state of a human subject based on processing information relating to the shape of the dicrotic notch of at least one pressure pulse of his proximal non-hyperemic pressure waveform and either the absence of dicrotic notches along his distal non-hyperemic pressure waveform or the shape of the dicrotic notch of at least one pressure pulse of his distal non-hyperemic pressure waveform if present to calculate the value of a PTC parameter indicative of the severity of the lesion.