Unilateral pulmonary artery thromboembolic occlusion in patients: Is distal arteriopathy a consequence?

The characteristics and post-operative outcomes of eleven patients with total unilateral (UNI)pulmonary artery (PA) thromboembolic occlusion were compared with those of some 600 patients who underwent bilateral (BI) thromboendarterectomies during the same time period. METHODS: Pre-operative historical, physical and laboratory features and post-operative outcomes of these two groups were analyzed. RESULTS: The UNI group had no distinct historical features; however, they were younger (32± 10 years) than the BI group (57 ± 15) and dominantly female (10/11) versus a male predominance (62%) in the BI group. A small lung by chest X-Ray was common (7/11) in the UNI group. Pre-operatively, significantly lower PA mean pressures (30± 12 vs 46 ± 12 mmHg) and calculated pulmonary vascular resistance (360 ± 293 vs 901 ± 467 dynes-sec-cm^-5) were present in the UNI group. Post operatively 4 UNI patients developed unilateral rethrombosis (2 immediate; 2 late at several years post-surgery); this occurred in only one BI patient. Furthermore, of 6 patients in whom UNI occlusion had been present for more than one year, reperfusion was poor in four despite an adequate thromboendarterectomy in all. Postoperative pulmonary angiograms in two of these disclosed apparent atrophy of central and distal pulmonary arteries Conclusions: Prior observations in animal models indicate that unilateral PA occlusion is followed by development of a post-obstructive arteriopathy in the resistance arteries of the occluded lung. The unusual outcomes in this unique group of 11 patients suggest that these patients may develop a similar arteriopathy which requires special management considerations at surgery and in the post-operative period.