Relative contraindications include Age (single lung recipients must be < 65; double lung recipients, < 60; and heart-lung recipients, < 55) Current cigarette smoking Previous thoracic surgery For some cystic fibrosis patients and at some medical centers, lung infection with resistant strains of Burkholderia cepacia, which greatly increases mortality risk Single and double lung procedures are about equally common and are at least 8 times more common than heart-lung transplantation.