Even if the HeartMate 3TM left ventricular assist device is associated with excellent outcomes, complications, such as pump thrombosis continue to affect patients on hemodynamic support. We report the history of a 68-year-old man who underwent implantation of an HeartMate 3TM as a bridge to transplantation. Nineteen months later, he developed signs of heart failure leading to cardiogenic shock. Neither clinical examination nor parameters from the device allowed a clear-cut diagnosis. Only surgical exploration revealed the presence of clots between the polyethylene terephthalate (Dacron®) and polytetrafluoroethylene tubes. This constitutes a weakness of this device for which we propose to the manufacturer for minimal modifications to overcome the problem.