Mildly positive TMT means that there might be a blockage in the blood supply  to the heart. And when the patient is running or climbing stairs or during exertion stress the heart is not getting sufficient blood supply. You need to confirm the same by doing a stress thallium or a stress echocardiography and if you want to skip them you can directly go for the gold standard test the angiography which will give the exact percentage of blockage in the blood vessels supplying blood to the heart. mean while she should start on anti platelets and blood thinners another supportive medications to prevent a heart attack