CT pulmonary angiography: an over-utilized imaging modality in hospitalized patients with suspected pulmonary embolism

Abstract

AimsTo determine if computed tomographic pulmonary angiography (CTPA) was overemployed in the evaluation of hospitalized patients with suspected acute pulmonary embolism (PE).MethodsData were gathered retrospectively on hospitalized patients (n=185) who had CTPA for suspected PE between June and August 2009 at our institution.ResultsCTPA was done in 185 hospitalized patients to diagnose acute PE based on clinical suspicion. Of these, 30 (16.2%) patients were tested positive for acute PE on CTPA. The Well's pretest probability for PE was low, moderate, and high in 77 (41.6%), 83 (44.9%), and 25 (13.5%) patients, respectively. Out of the 30 PE-positive patients, pretest probability was low in 2 (6.6%), moderate in 20 (66.7%), and high in 8 (26.6%) (p=0.003). Modified Well's criteria applied to all patients in our study revealed 113 (61%) with low and 72 (39%) with high clinical pretest probability. When modified Well's criteria was applied to 30 PE-positive patients, 10 (33.3%) and 20 (66.6%) were found to have low and high pretest probability, respectively (p=0.006). D-dimer assay was done in 30 (16.2%) of the inpatients with suspected PE and all of them were found to have elevated levels. A lower extremity duplex ultrasound confirmed deep venous thrombosis in 17 (9.1%) of the patients with suspected PE, at least 1 week prior to having CTPA.ConclusionUnderstanding the recommended guidelines, evidence-based literature, and current concepts in evaluation of patients with suspected acute PE will reduce unnecessary CTPA examinations.

Role of Transthoracic Lung Ultrasonography in the Diagnosis of Pulmonary Embolism: A Systematic Review and Meta-Analysis

“…In recent years, CTPA has replaced PA as the gold standard for the diagnosis of PE [ 2 ]. It has been reported that the use of CT scan has increased from 3 to 70 million between 1980 and 2007 [ 11 ]. Whereas in patients undergoing CTPA for suspected PE, the prevalence of PE is only 5% to 10% in America and 20% to 30% in Europe [ 37 – 39 ].…”

“…In addition, it is associated with an increased risk of radiation exposure [ 2 , 4 , 5 ]. In the United States, 1.5%-2.0% of malignant tumors are associated with CT scan and the incidence of contrast-induced nephropathy after having CTPA in patients suspected of PE is up to 12% [ 11 ]. Therefore, we have a responsibility to find new diagnostic tools to reduce the number of unnecessary CTPA, such as TLS.…”

“…In recent years, CTPA has replaced PA as a first-line method for the diagnosis of PE, because of its easy availability, high accuracy and ability of differential diagnosis [ 6 , 9 ]. However, only 13%-33% of patients with suspected acute PE are tested positive for acute PE on CTPA [ 10 , 11 ]. Meanwhile, the use of CTPA results in significant exposure to ionizing radiation, as well as a risk of contrast nephropathy.…”

“…Meanwhile, the use of CTPA results in significant exposure to ionizing radiation, as well as a risk of contrast nephropathy. In addition, in most hospitals, particularly in developing countries, CTPA cannot be performed directly in the emergency room [ 11 ].…”

Proteomics in thrombosis research

“… 5 , 6 Because of its low specificity for VTE, D‐dimer is limited to ruling out VTE in low‐probability cases, whereas diagnostic imaging is necessary to rule out or confirm diagnosis in medium‐ or high‐probability cases. With less than 20% of computed tomography pulmonary angiograms performed on suspicion of PE confirming the diagnosis, 7 , 8 , 9 more specific biomarker‐based tools implemented in the diagnostic workup have potential to reduce unnecessary imaging. Several studies have proposed biomarker candidates for acute VTE (e.g., p‐selectin, microRNAs), 10 , 11 but none have yet translated to clinical implementation.…”