Generally, taking Lantus (insulin glargine) and Janumet (sitagliptin/metformin) together is safe and very common, even with a history of blood clots and stents. Managing your blood sugar effectively is actually key to protecting your blood vessels and heart. Since you have stents, avoiding low blood sugar (hypoglycemia) is very important. Please continue to monitor your blood sugars closely and discuss your regimen with your doctor, who will also monitor your kidney function to ensure these remain the safest options for you.