Value of negative spiral CT angiography in patients with suspected acute PE: analysis of PE occurrence and outcome

Abstract

The aim of this study was to analyze pulmonary embolism (PE) occurrence and retrospective clinical outcome in patients with clinically suspected acute PE and a negative spiral CT angiography (SCTA) of the pulmonary arteries. Within a 35-month period, 485 consecutive patients with clinical symptoms of acute PE underwent SCTA of the pulmonary arteries. Patients with a negative SCTA and without anticoagulation treatment were followed-up and formed the study group. Patient outcome and recurrence of PE was evaluated retrospectively during a period of 6 months after the initial SCTA, and included a review of computerized patient records, and interviews with physicians and patients. Patients were asked to fill out a questionnaire concerning all relevant questions about their medical history and clinical course during the follow-up period. Special attention was focused on symptoms indicating recurrent PE, as well as later confirmation and therapy of PE. Of the 485 patients, 325 patients (67%) had a negative scan, 134 (27.6%) had radiological signs of PE, and 26 (5.4%) had an indeterminant result. Of 325 patients with a negative scan, 269 (83%) were available for follow-up. The main reasons for loss to follow-up were change of address, name, or phone number, or non-resident patients who left abroad. Of 269 patients available for follow-up, 49 patients (18.2% of 269) received anticoagulant treatment because of prior or recent deep venous thrombosis (32.6%) or a history of PE (34.7%), cardiovascular disease (18.4%), high clinical probability (8.2%), positive ventilation-perfusion scan (4.2%), and elevated D-dimer test (2%). The remaining 220 patients, who did not receive anticoagulant medication, formed the study group. Of this study group, 1 patient died from myocardial infarction 6 weeks after the initial SCTA, and the postmortem examination also detected multiple peripheral emboli in both lungs ( p=0.45%; 0.01-2.5, 95% confidence interval). The PE did not occur in any other patient. In patients with suspected PE and negative SCTA without anticoagulant therapy, the risk of recurrent PE in this study was less than 1% and similar to that in patients after a negative pulmonary angiogram. Therefore, we conclude that patients can be managed safely without anticoagulation therapy; however, this approach may not be appropriate for critically ill patients and those with persistent high clinical suspicion of acute PE.

Severity assessment of pulmonary embolism using dual energy CT – correlation of a pulmonary perfusion defect score with clinical and morphological parameters of blood oxygenation and right ventricular failure

“…In addition to a fast and accurate PE diagnosis with a high negative predictive value of a negative examination for an adverse outcome in patients with suspected PE [6], CTPA offers a variety of imaging features that are helpful for an individual risk assessment when PE is confirmed, as they are related to the haemodynamic severity and patient outcome, e.g. the right to left ventricular short-axis diameter ratio (RV/LV ratio) and the diameter of the central pulmonary artery [7].…”

Spiral computed tomography of pulmonary embolism

“…The authors concluded that in patients with negative spiral CT, clinical outcome was comparable to that in patients with negative V/Q scintigraphy or negative pulmonary angiography. In the author9s institution, a retrospective study of patients who underwent SCTA for suspected PE between 1993-1995 showed that in 260 cases with negative SCTA, where anticoagulation was withheld, there was only one recurrent PE (0.4%) [32]. Recently, GOODMAN et al [33] followed patients who had negative imaging results and who were not anticoagulated for 3 months.…”

Role of Multislice Computed Tomography of the Thorax for the Evaluation of Suspected Pulmonary Embolism

“…On the other hand, subsegmental emboli have a much greater likelihood of being asymptomatic and resolving without treatment. MDCT has been shown to provide better visualization of the subsegmental vessels, 40 but appears to have a similar negative predictive value (95%-99%) 31,32,41 as SDCT. This includes data from the recent Prospective Investigation of Pulmonary Embolism Diagnosis II trial, which compares MDCT against a composite reference diagnosis using a combination of clinical and other imaging modalities.…”