The diagnosis of pulmonary embolism (PE) in the non-pregnant population relies on clinical pre-test probability, D-Dimer and chest imaging studies. Physiologic changes of pregnancy affect the predictive power of the clinical pre-test probability and clinical impression as well as that of D-dimers. Therefore, clinicians may rely more heavily on imaging studies. Surveys show that over half of thoracic radiologists use CT pulmonary angiogram (CTPA) as a first line test; however, there are no available outcome studies of CTPA to support its use.The purpose of this study is to evaluate outcomes of negative CTPA in suspected PE in the pregnant population.
A retrospective review of pregnant patients with negative consecutive CTPAs between 2004 and 2008 was conducted. CTPAs and medical records were reviewed. Data collected include clinical presentation, risk factors, presence or absence of PE on CTPA or evidence of venous thromboembolism (VTE) on any subsequent imaging study. Radiological and medical record follow up data on events of VTE at 3 months following the date of CTPA were also extracted.
342 patients with suspected PE and negative CTPAs were reviewed. Dyspnea (75%) and chest pain (65%) were the most common complaints. Personal history and family history of VTE were identified in 5.2% and 4.4% of patients respectively. Positive smoking history was obtained in 21% of patients. 271 had a technically adequate study, 68 had some technical limitation and 3 were non-diagnostic. Out of 342 patients, 60% had compression ultrasonography (CUS) within 48 hours of the CTPA and 12 were lost to follow up. There were no VTE events at 3 months.
Despite the lack of validated clinical prediction tools and the debated use of D-dimer tests in the pregnant population, this study showed no reports of VTE events at 3 months following negative 4-row multidetector CTPAs in pregnancy.
CTPAs may safely exclude pulmonary embolism in pregnancy based on this retrospective outcome study but a prospective evaluation is still needed.
Ghada Bourjeily, No Financial Disclosure Information; No Product/Research Disclosure Information