Pulmonary embolism (PE) requires early diagnosis and treatment due to its association with high mortality and morbidity rates. The diagnosis of PE can be difficult because of symptoms are not always present and nonspecific (cough, dyspnea, hemoptysis and chest pain).
In current clinical practice, lung perfusion scintigraphy (LPS) is mainly used to exclude PE, especially in patients with contrast medium allergy, nephropathy or pregnancy.
The aim of this study was to highlight the role of LPS in the management of patients with suspected PE admitted to our Policlinic Hospital as an emergency in the “on call” 24hrs service.
We retrospectively revised all LPS performed from January 2012 to November 2014; 1145 patients that underwent LPS in the suspect of PE or in presurgery evaluation.
According to the EANM guidelines, LPS consisted in intravenous injection of 120–200 MBq of 99mTc – Macro Aggregated Albumin (99mTc-MAA) followed by images acquisition in supine position in at least four standard projections: posterior, anterior, left and right posterior oblique; eventually associated to a single photon emission tomography (SPET) acquisition.
We restricted our analysis at the exams performed as an emergency, in the “on call” 24hrs service including Saturday, Sunday and holidays; all exams were performed within 4 hours from the PE suspect onset.
891/1145 patients underwent LPS as an emergency; 528/891 were from emergency unit, 108/891 from pneumology, 56/891 from medicine unit, 52/891 from neurology, 25/891 from cardiology, 24/891 from surgery unit, 22/891 from orthopedic unit and the remaining 76/891 from other departments. 175/891 (20%) presented chest pain, 413/891 (46%) dyspnea, 96/891(11%) both symptoms and 207/891 (23%) none. All patient previously underwent D-dimer evaluation and 811/891 (91%) presented an high value (> 0.5 mg/L).109/891 (12%) had a contrast medium allergy or nephropathy. 128/891 (20%) were positive for PE; among these 72/128 (56%) had 1 wedge-shaped perfusion defect corresponding to anatomic regions of the lung, 38/128 (30%) had 2 defects and the remaining 18/128 (14%) had 3 or more defects. All positive patients were promptly treated; the remnants negative patients were followed in the suspect of other diseases; none of these revealed PE in the following days.
LPS has a fundamental role in PE diagnosis thanks to its high sensitivity. It presents several advantages: shorter time of execution, lower radiation exposure, absence of contraindications, absence of adverse reaction and lower costs. LPS can also be performed in patients with severe medical condition (e.g. patients on stretcher, in assisted ventilation). Our experience revealed the importance of performing LPS in emergency service that ensures the execution in not more than 4 hours from the request. LPS has equally importance in diagnosing and excluding PE because in both cases allows the correct diagnostic and therapeutic flowchart. We suggest that the LPS “on-call” 24hrs service should be present in at least one referral Hospital, thanks to the positive impact of this service in the patient management and in cost savings.