Recurrence Triangle for Venous Thromboembolism (VTE). Patient A: major transient risk factor associated VTE; patient B: minor/weak risk factor associated VTE, such as travel, estrogens, minor immobility, minor surgery; patient C: woman with true unprovoked VTE; patient D: man with unprovoked VTE. Abbreviations: DD, D-dimer; VTE, venous thromboembolism.VTE is a proximal deep vein thrombosis or pulmonary embolism.HERDOO2 score is only to be used in women.