RESUMEN
OBJECTIVE: To evaluate the association between the depth of trophoblastic infiltration and serum vascular endothelial growth factorconcentration in patients with an ampullary pregnancy. METHODS: This prospective cross-sectionalstudy involved 34 patients with an ampullary ectopic pregnancy who underwent salpingectomy between 2012 and 2013. Maternal serum vascular endothelial growth factor concentrations were measured using Luminex technology. Trophoblastic invasion was classified histologically as follows: stage I, limited to the tubal mucosa; stage II, reaching the muscle layer; and stage III,involving the full thickness. The qualitative data were compared using Fisher's exact test. The nonparametric Kruskal-Wallis and Mann-Whitney tests were used to evaluate differences in serum vascular endothelial growth factor among the degrees of trophoblastic invasion. ROC curves were constructed to determine vascular endothelial growth factor cut-off values that predict the degree of tubal invasion based on the best sensitivity and specificity. RESULTS: Eight patients had stage I trophoblastic invasion, seven had stage II, and 19 had stage III. The median serum vascular endothelial growth factorconcentration was 69.88 pg/mL for stage I, 14.53 pg/mL for stage II and 9.08 pg/mL for stage III, with a significant difference between stages I and III. Based on the ROC curve, a serum vascular endothelial growth factor concentration of 25.9 pg/mL best differentiated stage I from stages II and III with asensitivity of 75.0%, specificity of 76.9%, and area under the curve of 0.798. CONCLUSIONS: The depth of trophoblastic penetration into the tubal wall isassociated with serum vascular endothelial growth factor concentration in ampullary pregnancies.