Effects of poorly perfused peripheries on derived transit time parameters of the lower and upper limbs

A simple and non-intrusive approach termed the pulse transit time ratio (PTTR) has recently been shown to be a potential surrogate of the ankle-brachial index (ABI). PTTR is based on the principle of PTT, which is known to be temperature-sensitive. In this study, 23 healthy adults with normally perfused peripheries and 10 with poorly perfused peripheries were recruited. No significant change in PTTR was observed between those with cold (1.287+/-0.043) and normal (1.290+/-0.027) peripheries (p>0.05). A cold periphery may cause pulse waveform changes and indirectly affect PTT owing to poor skin microcirculation, but may have a limited effect on PTTR, which is useful as an ABI alternative.