Pregnancy-Adapted YEARS Algorithm for Diagnosis of Suspected Pulmonary Embolism
Liselotte M. van der Pol, M.D., Cecile Tromeur, M.D., Ingrid M. Bistervels, M.D., Fionnuala Ni Ainle, M.D., Thomas van Bemmel, M.D., Laurent Bertoletti, M.D., Francis Couturaud, M.D., Yordi P.A. van Dooren, M.D., Antoine Elias, M.D., Laura M. Faber, M.D., Herman M.A. Hofstee, M.D., Tom van der Hulle, M.D.
BACKGROUND
Pulmonary embolism is one of the leading causes of maternal death in the Western world. Because of the low specificity and sensitivity of the d-dimer test, all pregnant women with suspected pulmonary embolism undergo computed tomographic (CT) pulmonary angiography or ventilation–perfusion scanning, both of which involve radiation exposure to the mother and fetus. Whether a pregnancy-adapted algorithm could be used to safely avoid diagnostic imaging in pregnant women with suspected pulmonary embolism is unknown.
METHODS
In a prospective study involving pregnant women with suspected pulmonary embolism, we assessed three criteria from the YEARS algorithm (clinical signs of deep-vein thrombosis, hemoptysis, and pulmonary embolism as the most likely diagnosis) and measured the d-dimer level. Pulmonary embolism was ruled out if none of the three criteria were met and the d-dimer level was less than 1000 ng per milliliter or if one or more of the three criteria were met and the d-dimer level was less than 500 ng per milliliter. Adaptation of the YEARS algorithm for pregnant women involved compression ultrasonography for women with symptoms of deep-vein thrombosis; if the results were positive (i.e., a clot was present), CT pulmonary angiography was not performed. All patients in whom pulmonary embolism had not been ruled out underwent CT pulmonary angiography. The primary outcome was the incidence of venous thromboembolism at 3 months. The secondary outcome was the proportion of patients in whom CT pulmonary angiography was not indicated to safely rule out pulmonary embolism.
RESULTS
A total of 510 women were screened, of whom 12 (2.4%) were excluded. Pulmonary embolism was diagnosed in 20 patients (4.0%) at baseline. During follow-up, popliteal deep-vein thrombosis was diagnosed in 1 patient (0.21%; 95% confidence interval [CI], 0.04 to 1.2); no patient had pulmonary embolism. CT pulmonary angiography was not indicated, and thus was avoided, in 195 patients (39%; 95% CI, 35 to 44). The efficiency of the algorithm was highest during the first trimester of pregnancy and lowest during the third trimester; CT pulmonary angiography was avoided in 65% of patients who began the study in the first trimester and in 32% who began the study in the third trimester.
CONCLUSIONS
Pulmonary embolism was safely ruled out by the pregnancy-adapted YEARS diagnostic algorithm across all trimesters of pregnancy. CT pulmonary angiography was avoided in 32 to 65% of patients.
Comentario
Este estudio proporciona evidencias sobre la seguridad en el uso de un algoritmo diagnóstico para pacientes embarazadas con sospecha de TEP. Permite evitar la realización de un angioTC de tórax en una proporción significativa de embarazadas (particularmente en el primer trimestre) y la incidencia de eventos trombóticos durante el seguimiento es muy baja.
Hay algunos aspectos de este estudio que merecen ser examinados. La mayoría de las pacientes (43 de 47) con sospecha de TVP recibieron una ecografía de compresión de miembros inferiores, con un diagnóstico final de TVP en el 7%. Se realizó también una ecografía en 79 pacientes que no tenían signos clínicos de TVP, y hubo un diagnóstico adicional de TVP en 1 de ellos (1%). Por tanto, este estudio no evalúa el papel de la ecografía en el algoritmo YEARS, particularmente cuando se requiere una prueba diagnóstica de imagen.
En este estudio se utilizó angioTC de tórax como prueba de imagen torácica, y no evaluó la gammagrafía ventilación/perfusión (V/Q). Algunas evidencias indirectas sugieren que en las mujeres fértiles el angioTC de tórax es una prueba que podría asociarse a más complicaciones que la gammagrafía V/Q. Adicionalmente, habría sido interesante que el estudio hubiera proporcionado información adicional sobre los diagnósticos alternativos proporcionados por el TC.
En función de los resultados de este estudio, se debe utilizar el algoritmo YEARS para el diagnóstico de pacientes embarazadas con sospecha de TEP. Para los pacientes que requieren prueba de imagen, es recomendable solicitaruna ecografía de miembros inferiores como prueba inicial. En caso de que requiera una prueba de imagen torácica, se ha de realizar una gammagrafía de perfusión a mitad de dosis para aquellas sin enfermedad cardiopulmonar, y un angioTC de tórax para el resto.
Van der Pol LM, Tromeur C, Bistervels IM, et al. Pregnancy-Adapted YEARS Algorithm for Diagnosis of Suspected Pulmonary Embolism. N Engl J Med 2019; 380: 1139-1149.
