What leads to varicose veins? Varicose veins are mainly attributable to weakened or harmed valves during the veins, bringing about blood pooling along with the veins getting swollen and twisted. Deep Vein Thrombosis: This occurs whenever a blood clot is created while in the deep veins and produces a blockage. https://www.sgvascularctr.com/varicose-vein-treatment-in-singapore-everything-you-need-to-know/