The goal of this study was to establish whether changes in microvascular perfusion play an important role in the development of hypertension. To achieve this goal, we measured the photoplethysmographic waveforms recorded from the fingertips of patients with untreated hypertension. The photoplethysmographic waveforms were obtained from 60 healthy, normotensive male controls (NTs) and 30 untreated hypertensive male patients (HTs). The NTs were divided into two groups: a younger NT group (age 20 to 40 years, 30 individuals) and an older NT group (age 40 to 60 years, 30 individuals). The PPG waveform displayed a steep rise and a notch on the falling slope in the younger NT group. And for younger subjects, there were two positive waves (P1 and P2) and one negative wave (V).In the older NT group, a more gradual rise and fall was observed. For the HT group, no pronounced dicrotic notch was observed. A program was used to calculate the P2/P1 and P2/V ratios. The P2/P1 and P2/V ratios can indicate the perfusion to the fingertips during cardiac diastole. There were no significant differences in P2/P1 between the older NT group and HTs (0.37±0.07 versus 0.33±0.05, p>0.05).The P2/V ratios were significantly different between the older NT group and HTs (0.93±0.11 versus 0.59±0.08, p<0.05). These results indicate that there is a decrease in perfusion to the fingertips in hypertensive subjects during cardiac diastole.
