Periventricular lucency evaluated by second‐derivative finger plethysmography

Background: The purpose of the present paper was to clarify the etiologic and pathophysiologic bases of periventricular lucency (PVL). Methods: The relationship between PVL severity and hemodynamic variables derived by second‐derivative finger plethysmography (SD‐PTG) was studied. A total of 307 consecutively examined outpatients 60 years or older (mean age: 77.7 years; 149 men, 158 women) was enrolled. On the basis of brain computed tomography, PVL was classified into four grades (0–3) according to a modification of the classification of van Swieten. The grade of PVL was assessed at two points in each patient: anterior and posterior. The heights of the a, b, and d waves on the SD‐PTG waveform were measured from baseline. The b/a ratio, indicating distensibility of the aorta, and the d/a ratio, indicating peripheral resistance, were calculated. Results: An anterior PVL of grade 3 had a significantly higher b/a ratio and a significantly lower d/a ratio than that of grade 0 or grade 1 (both P < 0.05). For posterior PVL, the b/a ratio and the d/a ratio were similar for all four grades. The anterior PVL grade was compared with the posterior PVL grade in individual subjects. This comparison yielded six groups: four in which PVL grade was similar (0, 1, 2 or 3) in both regions, one in which the grade for anterior PVL was higher than that for posterior PVL (predominantly anterior group), and one in which the grade for posterior PVL was higher than that for anterior PVL (predominantly posterior group). In patients with predominantly anterior PVL, the b/a ratio and incidence of lacunae were significantly higher than that in patients with predominantly posterior PVL. Conclusion: These findings indicate that the frontal white matter is susceptible to hemodynamic stress. It is suggested that decreased aortic distensibility may promote fibrohyaline thickening of the medullary arteries, increasing the risk of PVL.