A 66 y/o Man was admitted to our hospital because of dyspnoea and elevated body temperature (38.1°C). A month prior, the pt. suffered an ischaemic CVA. Hx also revealed a MI, 7 years ago and a TIA. PE: BP 130/80 mmHg, pulse 102 BPM and regular; the central venous pressure was elevated. RR 36 breaths/min. Examination of the lungs and heart revealed no abnormalities. The right lower extremity was red, warm and swollen and painful on palpation. most likely diagnosis?