EXTENT OF CENTRILOBULAR AND PANACINAR EMPHYSEMA IN SMOKERS LUNGS - PATHOLOGICAL AND MECHANICAL IMPLICATIONS

In order to quantify the extent of centritobular (CLE) and panacinar ( PLE) emphysema and the degree of the possible overlap between the two forms in smokers, the lungs of 25 smokers undergoing lung resection fo r peripheral lung rumours were studied. The extent of CLE and PLE was assessed by point counting, and the lungs were classified as having pu re CLE (C, n=5), predominant CLE with areas of PLE (CP, n=7), predomin ant PLE with features of CLE (PC, n=7), and pure PLE (P, n=6) accordin g to the percentage of lung involved by either form. Preoperative pulm onary function tests and the score of inflammation and the diameters o f the small airways were also measured. Mean linear intercept (Lm), a measure of mean interalveolar wall distances and forced expiratory vol ume in one second (FEV(1)) were similar in the four groups. Small airw ay pathology was a predominant feature in lungs with CLE, and was sign ificantly decreased in a stepwise fashion as the amount of PLE increas ed. This was especially so for the amount of muscle in the airway wall and the diameters of the airways. By contrast, lung compliance was hi gher in panacinar than in centrilobular emphysema. We conclude that: 1 ) smokers may reach similar values of airflow obstruction and parenchy mal destruction in two completely different ways, developing either ce ntrilobular or panacinar emphysema; 2) these two types of emphysema ma y be present in pure form or may overlap each other, but one type is a lways clearly predominant; and 3) the degree of either form has import ant consequences on the degree of airway abnormality and on the mechan ical properties of the lung.