108: Overview of Lung Transplantation with Anatomy and Pathophysiology

Introduction

While there are numerous challenges that face the recipient and practitioner, the field of lung transplantation continues to improve and expand with technical, immunological, and donor-related advancements. The utility of thoracic organ transplantation for end-stage lung disease was not meaningfully realized until the development of cyclosporine in the 1980s. In the preceding decades (1963–1983), fewer than 50 lung transplants were performed worldwide, and no recipient survived for more than 10 months. Early lung transplants failed for four principal reasons: nonfunction of the primary graft, dehiscence of the bronchial anastomosis, acute lung rejection, and pneumonia. Developments in surgical technique, perioperative care, and immunosuppressive drugs culminated in the first successful long-term lung transplant, performed in 1983 in a patient with idiopathic pulmonary fibrosis.¹ The technical highlights of this operation included the concept of using an omental wrap around the bronchial anastomosis to restore bronchial artery circulation and prevent dehiscence, careful patient selection, and effective long-term immunosuppression with cyclosporine. Shortly thereafter, Patterson et al.² performed the first successful double-lung transplant in a patient with emphysema (Fig. 108-1).

As the discipline matured, the application of these surgeries changed based on disease-specific factors. Techniques were derived based on specific patient needs as the science progressed. While living-related lobar transplant is no longer in high demand, primarily because of the creation of the current Lung Allocation Score (LAS), it continues to be a vital tool for the occasional patient. Drs. Barr and Starnes have further defined this role in Chapter 110. Single- and double-lung transplantations are the current mainstays of treatment for end-stage pulmonary disease. The essence of these techniques has not changed much in the past decade; however, the choice of operation, sidedness, and advancements are discussed in detail by Drs. Bharat and Patterson in Chapter 109. Combined heart–bilateral lung transplantation for multiple-organ failure in patients with primary pulmonary disease was once a more common surgery until it was observed that transplanting lungs earlier rather than later in these patients could prevent cardiac failure.

The advent of better therapies for pulmonary hypertension, closer monitoring of right heart function, and a better understanding of secondary pulmonary hypertension have had a significant impact on the need for combined heart–lung transplant. Heart–bilateral lung transplantation is now reserved for patients with other coexisting primary pulmonary and cardiac diseases, primarily of a congenital nature. The number of heart–lung transplantation procedures has declined over the years; however, new indications continue to arise for selected patients.

Some of the most exciting areas of advancement are in the mechanical means of supporting both the recipient and the donor lung, as well as a heightened awareness of the immunology of the lung transplant patient. Ex vivo ...