The impact of lung perfusion scintigraphy in the emergency management of patients with suspected pulmonary embolism.

Aim: The aim of our study was to highlight the role of Lung Perfusion Scintigraphy (LPS) in the management of patients with suspected pulmonary embolism (PE) admitted as urgent and in the “on-call” 24hrs service. Materials and Methods: We retrospectively revised 2166 LPS performed for PE suspicion(years 2012-2016). The relation between LPS and symptoms, risk factors (i.e. arythmia, drugs, surgery, thrauma, deep venous thrombosis), D-dimers dosage and other diagnostic imaging examination (Chest X-ray and/or Computed Tomography (CT)) were evaluated by contingency tables and Odds Ratio (OR). Results: 1730/2166 (79.8%) were urgent and admitted as emergency; 1026/1730 (59.3%) were performed during the on-call 24hrs service. The request of LPS came from emergency-room in 981/1730 (56.7%) patients, pneumology in 187/1730 (10.8%), neurology in 83/1730 (4.8%), internal medicine in 112/1730 (6.5%), surgery in 90/1730 (5.2%), cardiology in 57/1730 (3.3%), and other departments in 220/1730 (12.7%). LSP resulted positive for PE and treated in 294/1730 (17%) patients, while negative in 1436/1730 (83%). The presenting symptoms, single or differently associated, were chest pain in 536/1730 (31%), dyspnea in 900/1730 (52%), cough in 225/1730 (13%) and none in 69/1730 (4%); only the presence of dyspnea was significantly related to the presence of PE (OR=1.596 p=0.003); chest pain and cough were not related to PE (p> 0.005). Risk factors were present in 960/1730 (55.5%) patients and none of them were related to PE detected by LPS (p> 0.005). D-dimer dosage was increased in 1678/1730 (97%) patients and were not related to PE detected by LPS (p> 0.005). A previous diagnostic exam was performed in 1306/1730 (75.5%) patients. The Chest X-ray and/ or CT resulted negative in 332/1306 (25.4%), suspected for PE in 319/1306 (24.4%), non-specific with pleural effusion in 245/1306 (18.8%) and non-specific with inflammatory interstitial diseases in 410/1306 (31.4%). LPS resulted positive for PE in 46/332 (13.8%) with negative Chest X-ray and/or CT, in 75/319 (23.4%) with suspected PE, in 37/245 (15.2%) with pleural effusion and in 60/410 (14.7%) with inflammatory interstitial diseases. The relation between LPS and other imaging resulted statistically significant (χ2=17.5 p=0.001). Conclusions: LPS has a key role in the assessment of PE, optimizing the management of patients who do not require admission to intensive care unit avoiding high costs and overcrowded hospitalization. Our data support the need of LPS performed as emergency in on-call 24hrs service in each metropolitan area.