What is a lung transplant?


The View From the Inside.
The View From the Inside.

A lung transplant is a treatment, not a cure.  This is the single most important fact to keep in mind when considering a transplant.  As explained to me early on, a transplant is the process by which an untreatable disease is replaced with a treatable one.  Treatable in that you have to take anti-rejection/immune-suppression medications after the transplant to prevent chronic rejection and death.  However, for me and for the vast majority of patients with a disease that would otherwise prove fatal, this is an acceptable trade-off.  I felt that way going in, and I definitely feel that way some three years and change after the operation.

A lung transplant can be used to replace one or both lungs.  Some diseases require a double-lung replacement (e.g., cases with pulmonary hypertension), while others lend themselves well to a single-lung replacement (such as early- to mid-stage IPF).

Here are a  few details about donor organ allocation and patient eligibility that are specific to lung transplantation:

Allocation of donor lungs is not covered by a Status Level system, which enables a patient to move higher up the waiting list as he (or she) gets sicker, and is currently reserved for hearts, livers, and multiple-organ transplants.  Donor lungs are allocated through a basic Time-On-List method, therefore time is the primary factor used to determine when a lung transplant candidate will be transplanted.  In addition to time, there are other medical and/or physical categories of matching that are also involved, as follows:

1.  Size--You are a certain size, and so are your lungs.  People's sizes vary a great deal; so it is with lungs.  Obviously, a child's lungs could not support a grown adult, but the matching must be closer than that.  The height of the candidate and the height of the donor need to be as close as possible.

2.  Blood type--Basically speaking, the blood type of the donor has to match the blood type of the candidate.  Unlike with other organ transplants, with lungs, donor organs from one blood type are transplanted into candidates of the same blood type.  There is no exploitation of Type O+ (the "universal donor") lungs for candidates with other blood types, as has been the case with livers until very recently.

In addition to the matching categories listed above, the following factors are also sometimes used to determine a patient's eligibility for a given donor organ (or even sometimes a transplant in the first place), so I will also include them as well:

A.  CMV status matching of candidate and donor--CMV is sometimes known as the "daycare virus"; over 80% of the adult population of the US has been exposed to it and has antibodies for it.  If the donor and the candidate are not matched for CMV, there can be problems later with CMV infection, so some centers try to match prior to the transplant.  This policy varies, however, from center to center, and is (in my opinion) an exclusionary practice disguised as a protective measure.  As the transplant center should prophylactically treat for possible CMV infection with extended IV Gancyclovir infusions anyway, matching for CMV is essentially unnecessary.

B.  Prednisone dose level at time of transplant--It is commonly thought that the candidate should be taking no more than 20 mg. per day of Prednisone when they are transplanted.  This, too, is (in my opinion) another exclusionary practice that finds popularity at transplant centers attempting to stack all of the odds in their favor.  Common sense would tell you that the nature of most lung diseases, and the average waiting list time involved, makes increased steroid use a fact of life.  As the delayed healing effects of steroids are handled by the use of staples when closing the incision, and steroid use is required after the transplant anyway, this looks more and more like another restriction than a sensible requirement.

C.  Six-minute walk performance--This is another controversial issue (to me, anyway), that can be used as a tactic by transplant centers attempting to improve their success rates.  In fact, the "Welcome to the Program" letter I received from the transplant center at which I was initially listed stated in no uncertain terms that I could, at some point, become too sick to transplant.  Curiously, this never seems to be an issue with Status-Level allocated organs such as hearts and livers.  In fact, due to the very nature of the Status Level system, you basically have to be a day from death to even GET transplanted--there is always somebody sicker that moves in front of you on the list.  The fact is that at many centers, the six-minute walk has somehow become the standard by which a lung transplant candidate's ongoing transplantability is judged.  As such, it has become an object of fear that effectively undermines the relationship of trust that must exist between the patient and the transplant center.  I urge transplant centers to do a better job of listing patients earlier and being less restrictive after they are listed.

D.  Weight--Probably the most difficult issue facing many transplant candidates is pre-operative weight.  Unfortunately, a common side effect of pre-transplant steroid therapy is weight gain.  The reason given by transplant centers is that an overweight condition inhibits the patient's ability to rehabilitate.  The fact is that as the efficiency of a patient's oxygen system--the lungs, heart, and  blood--decreases through the course of their disease, it gets harder and harder to carry excess weight, so losing some only makes life easier anyway.  This one is probably legitimate.

This, then, is a brief summary of some of the basic operational and political issues regarding a lung transplant.  If you need to know what exactly is done during the procedure, ask your transplant surgeon.  My advice, however, is not to ask--there is a curse of knowing too much.  Let me put it this way--they disconnect a lot and reconnect only what is necessary.  Just get the best medical talent you can find, do what they say, stay viable until you get the call, and the rest will work itself out.