DIAGNOSTIC RADIOLOGY

Abstract

Thirty-four men with left ventricular mechanical dysfunction were admitted to an intensive care unit with either an acute myocardial infarction (Group 1, n = 18) or worsening of clinical respiratory signs and symptoms in the setting of a chronic congestive cardiomyopathy (Group 2, n = 16). On admission, all individuals had pulmonary venous hypertension classified as at least Grade 3 by standard radiographic criteria. In each subject, mean pulmonary capillary wedge pressure (mm Hg), extravascular lung water (EVLW) (ml/kg), and chest radiographs were serially evaluated. In the patients in whom pharmacologic therapy successfully returned left ventricular filling pressures to near normal levels (less than or equal to 15 mm Hg), the chest radiograph returned to its baseline level (defined by the discharge radiograph) later in the patients with chronic heart failure (5.1 +/- 1.0 days) than in the patients with acute myocardial infarctions (2.1 +/- 1.2 days, p less than 0.01). Radiographic changes in extravascular water (interstitial and alveolar edema) mirrored changes in EVLW, although EVLW was initially greater in Group 2 (16.3 +/- 1.8 ml/kg) than in Group 1 (10.7 +/- 1.3 ml/kg, p less than 0.01). In the patients in whom filling pressures either worsened or changed less than 3 mm Hg, EVLW and chest radiographs did not markedly change. It is concluded that changes in radiographic pulmonary edema mirror changes in indicator-dilution measurements of EVLW. Radiographic phase lag represents a slow decline in EVLW after therapy for heart failure, which is prolonged in patients with chronic failure and greater EVLW.