An enlargement of the diameter of the right descending branch (RDB) of the pulmonary artery in chest radiographs may serve as a sign of pulmonary arterial hypertension. We tried at first to establish exactly the normal values for men and women of different age, analysing the radiographs of 112 healthy subjects. There is a relationship of RDB diameter to sex and age. We compared the RDB diameters in 95 men suffering from chronic bronchitis with the pulmonary arterial pressure, flow, and resistance, and with the right ventricular work: a highly significant relationship of RDB diameter to all but the blood flow values was found. Considering (in men over 40 years of age) a diameter of the RDB of 18 mm. or more as pathological, the reliability of the diagnosis of pulmonary hypertension in chronic bronchitis was 72-2% with readable films, or 64-2% when not reliably readable chest films were included. Nevertheless, a similar comparison in patients with mitral stenosis indicates that the radiographic picture of pulmonary hypertension differs according to the initial disease. Here we discuss the factors which may influence the RDB diameter.Compensated chronic cor pulmonale in chronic bronchitis and its complications frequently escape diagnosis unless an elevated pulmonary artery pressure is found by right heart catheterization.Physical signs of hypertrophy of the right ventricle are rare in the initial stages of cor pulmonale in chronic bronchitis associated with hypoventilation, and electrocardiographic signs are rarely found at this time.Radiological signs of pulmonary hypertension are more useful, as was proved by numerous authors who studied the radiological symptomatology of pulmonary hypertension (Assmann, 1920;Carmichael, Julian, Jones, and Wren, 1954; Dejdar, Widimsky, Valach, Fejfar, and Bergmann, 1959; Van Epps, 1958;Goodwin, Cleland, Hunter, Davies, and Steiner, 1955;Healey, Dow, Sosman, and Dexter, 1949;Milne, 1963;Schwedel, 1946;Steiner, 1957; Teichmann, Drib, Daum, and Ourednfk, 1961). The signs which may be related to pulmonary hypertension are enlargement of the right ventricle, enlargement of the main trunk of the pulmonary artery, enlargement of the hilar branches of the pulmonary artery, in particular of the right descending branch (described also as truncus intermedius or arteria intermedia), narrowing of branches of the peripheral arterial bed, and pulsation of the hilar arteries. We think that some of these signs are not frequent in pulmonary hypertension, or depend too much on the subjective evaluation of the physician, or appear only in heart failure (Teichmann and Drab, 1963).There is general agreement that the most useful radiographic sign is the width of the shadow of the descending branch of the right pulmonary artery (RDB).To elucidate the diagnostic importance of the RBD, we investigated the relation between its diameter and any pulmonary hypertension. We compared catheterization data with the width of the RDB and we tried to find out the difference, if any, between the radiographic appe...

The pathogenesis of pulmonary hypertension in chronic bronchitis is still obscure, though the relation of pulmonary artery pressure and tension of alveolar gases has been recognized since the classical experiment of von Euler and Liljestrand (1946).Our interest in the site of resistance was aroused by the increased pulmonary.artery wedge pressure in cor pulmonale without overt pathological changes in the left heart. Most of these patients were middle-aged or older men and ischaemic heart disease was suspected. However, the coincidence of ischaemic heart disease with cor pulmonale was found to be less frequent than would correspond to their separate incidence in the general population (Kralova et al., 1965).Pulmonary artery wedge pressure is virtually an artefact and the result of interplay of several factors (Herles, 1966 654for gas analysis was taken from the femoral and pulmonary artery under strict anaerobic conditions.The 02 and CO2 content of the blood was determined by the method of Van Slyke and Neill (1924), the blood pH by the pH meter (Godart and Cambridge). The blood CO2 tension was calculated from the CO2 content and pH.Cardiac output was determained from oxygen consumption and the arterio-venous oxygen difference using the Fick's formula. Total pulmonary resistance and arteriolar resistance were expressed in arbitrary Wood's units calculated according to the following formulae. where mRAP is mean pressure in the right atrium, mPAP is mean pressure in the pulmonary artery, mPAWP is mean pressure in the wedged pulmonary artery, CO is cardiac output in 1./min., CI is cardiac index, TPR is total pulmonary resistance, PAR is pulmonary arteriolar resistance, and Wr is work of the right ventricle. Extra-arteriolar or post-arteriolar (EAPR) pulmonary resistance was calculated from the difference between total resistance and arterial resistance. In calculating total pulmonary resistance, the left atrial pressure was not deducted, since it had not been ascertained and the deduction of an arbitrary value of 5 mm.Hg does not increase the comparability of the figures. Extraarteriolar resistance includes both the resistances of pulmonary venules and the "resistance" of the left side of the heart.Pressures at rest in the right atrium exceeding 5 mm. Hg, in the pulmonary artery exceeding 20 mm.Hg, and in the wedged pulmonary artery reaching or exceeding 12 mm.Hg, were considered to be increased.To follow separately the influence of pulmonary hypertension and of heart failure, the group of92 patients with cor pulmonale was subdivided into 3 groups: (1) 45 patients who at the time of examination and for two on 7 June 2019 by guest. Protected by copyright.

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