ECHOCARDIOGRAPHIC AND RADIONUCLIDE PULMONARY BLOOD-FLOW PATTERNS AFTER TRANSCATHETER CLOSURE OF PATENT DUCTUS-ARTERIOSUS

Background Transcatheter occlusion of patent ductus arteriosus (PDA) h as been associated with protrusion of the occluder device into the lef t pulmonary artery (LPA). This study was conducted to evaluate the sig nificance of occluder protrusion and its implications for potential ob struction of the LPA and associated decrease of left lung perfusion. M ethods and Results Fifty-two patients underwent successful transcathet er PDA occlusion over a period of 5 years. In this study, 49 were reex amined between March and June 1995. In addition to clinical and echoca rdiographic examination, lung scintigraphy was performed. Protrusion i nto the LPA was present in 5 of 49 patients (10%). In these patients, maximal flow velocity in the LPA was significantly (P<.01) increased. Decreased left lung perfusion, defined as <40% of total pulmonary bloo d flow, was found in 7 or 49 patients (14%). Although mean left pulmon ary perfusion was significantly (P=.02) decreased in patients with pro trusion, there was considerable overlap with patients without protrusi on, and only a weak correlation was found (r=-.35, P=.01) between flow -velocity and left lung prefusion. Conclusions Our results demonstrate that protrusion of the device in the LPA in an infrequent finding. If present, it is associated with increased maximal flow velocity in the LPA and diminished left lung perfusion. However, echocardiography and lung scintigraphy are weakly correlated. Increased maximal blood flow velocities in the proximal LPA proved to be a poor indicator of impai red left lung perfusion. Also, decreased perfusion occurs in the absen ce of echocardiographic evidence of device protrusion.