Dr. Duane Davis – Thoracic Surgery

Fundoplication after Lung Transplant

a new article published in the annals of thoracic surgery on using fundoplication to prevent allograft (transplant) rejection in lung patients.

The theme of this article, along with many of the names of the authors should be familiar to readers – during my week with transplant surgeons down at Duke – I met with many of them to discuss gastroesophageal reflux and lung transplant (among other issues in transplant.)

Now Dr. Mathew Hartwig, along with Dr. Shu Lin, Dr. Duane Davis, Dr. Shekur Reddy along with several others in the department of lung surgery have published a study in the Annals of Thoracic Surgery, entitled, “Fundoplication After Lung Transplantation Prevents Allograft Dysfunction” discussing the role of GERD in lung transplant tissue rejection, and how use of early fundoplication procedures prevented graft rejection. In this study, it appears that fundoplication procedures helped preserve post-transplant lung function (in patients with proven GERD on pH probe testing). This certainly suggests that GERD plays a role in lung tissue damage in patients with measurable acid reflux.

I emailed Dr. Hartwig earlier this week for his comments – and I’ll update this post soon.

I met the young, dynamic Dr. Hartwig down at Duke and we briefly discussed his work in this area (before I raced off with Dr. Lin to the operating room.) Dr. Hartwig has been conducting animal studies examining the tissue changes in lung tissue exposed to gastric acids. He has also been heavily involved in several other studies on GERD and lung transplant recipients.

In the operating room with Dr. R. Duane Davis

Single lung transplant with Dr. R. Duane Davis, famous cardiothoracic surgeon, and chief of the Lung Tranplant program at Duke. Part of a series.

(Part of a series about the Lung Transplant Program at Duke University, in Durham, North Carolina).

3:40 am.. the surgical team keeps working steadily in the operating room as they wait for Dr. Reddy to arrive.. One diseased lung is being readied for removal to make room for the new organ. The anesthesia team maintains the patient’s oxygenation and blood pressure carefully, a delicate balance, using only one heavily damaged lung. The perfusionist stands by, to assist with CPB* (cardio-pulmonary bypass, also known as the heart-lung machine) if needed. [for this particular case – I was not present to witness this portion of the procedure]

at 03:45 we arrive, Dr. Reddy bringing in a wheeled cooler containing the organ. Quickly, Dr. Davis and another surgeon (one of the graduating thoracic surgery fellows) begins preparing the new lung for implantation.

The clock is ticking, and has been running since the moment the organ was removed, in that OR several states away. This is cold ischemia time – time when the organ is chilled, prior to implantation. The cold lessens the tissue damage, but doesn’t halt it completely. This is why organ procurement is such an orchestrated process, and why Dr. Davis is here, operating at 3 in the morning. Once the lung is removed from the icy solution and placed into the chest to start the implantation, the real clock (a wall mounted clock) is started, to keep track of warm ischemia time.

Warm ischemia time is the period during which the lung is being implanted into the recipient. This is when the most damage occurs to the harvested organ, and surgeons use several methods to limit the amount of warm ischemia that occurs. One of the ways they do this by infusing cold solutions intermittently while attaching the lung to the pulmonary arteries and veins (anastomosis) to re-establish blood flow prior to re-attaching the bronchus (the airway). The operating room clock is used to record the amount of warm ischemia so that the surgeons know when to re-infuse the solution and to keep track of the total ischemic time during the operation.

Once the lung is reattached by re-establishing both the blood supply from the recipient to the donor lung, and by connecting the airway – it’s time to re-inflate the lung. This is the most tense period of the operation – as surgeons wait to see if the new lung will function as intended. If not, the patient will be connected to ECMO (see below for more information on ECMO) to supply the lung with oxygen rich blood to prevent further injury. Often patients require ECMO for a short period of time after implantation.

One of the problems with lung transplantation is reperfusion injury, which begins at this point.

“Re-perfusion injury” itself is a generic term describing the injury that occurs to tissue once blood flow is re-established (whether this occurs during a treatment of a heart attack, stroke, organ transplantation or other disease process). A good way to think about re-perfusion injury is that this process occurs as part of the body’s (misguided) attempts to heal itself. Unfortunately, as the name implies – this sequelae of biochemical events results in more damage to the organ(s) itself. Medications are also used during this process to limit the amount of reperfusion injury.

Once the lung is functioning (breathing) and the patient is able to maintain oxygenation, and other vital signs (blood pressure and heart rate) the incisions are closed, and the patient is taken to the intensive care unit. From there, if everything goes well, the patient will be extubated (breathing tube removed and ventilator turned off) and out of bed and walking by the next day. (In lung transplant, like all lung surgeries, early ambulation is critical.)

* ECMO (extracorporal membraneous oxygenation) by veno-venous access, which is a therapy very similar to cardiopulmonary bypass is also available.

Watching Dr. Davis operating is an experience in itself – among lung transplant surgeons, he is a legend along with Dr. Joel Cooper and Dr. Ken McCurry. Dr. Davis, locally known as “Dr. McDreamy” for his classic good looks; with silver blond hair and piercing blue eyes is affable and kind. He was patient with my multiple questions, which is important; as in lung transplant it seems like every answer you discover just leads to another layer of questions.

We’d met before, on one of his visits to the hospital in Virginia where I worked, but I didn’t know him as well as Dr. Shu Lin, who initially extended the invitation for me to visit the Lung Transplant service when I’d expressed interest.

Now here in the operating room, performing one of his many transplants (he’s done around 750 to 800 lung transplants), Dr. Davis was focused, but confident. He remained in tune to his patient underneath all those drapes, noticing every change in respiration, heart rate or blood pressure before anesthesia could bring it to his attention, even during the more delicate portions of the operation. I’d come into this part of the procedure after a long day myself, starting at 2am the previous day in Virginia, then meeting with Dr. Lin, rounding on patients, witnessing several cardiac operations before flying off with Dr. Reddy. It all culminated in the operating room with Dr. Davis more than 24 hours later – watching him operate, and watching the lung struggle to take its first breaths in its new home. Somehow, all tiredness vanishes at moments like this [though it returns with a vengeance.]

In this case – the lung struggled and needed a very short period of ECMO before recovering in the operating room*. During all of this, Dr. Davis was calm, and in control. After a few tense minutes, the lung recovered and ECMO was discontinued. The remainder of the case proceeded uneventfully, and I stumbled home to get a few hours sleep before my formal interview with Dr. Davis the next day. It was, all told – another successful surgery for Dr. R. Duane Davis, the patient and the Duke Lung Transplant Program.

* This is related to the physiological function of the donor lung, and the patient response – and not due to technical aspects of the surgery.

Additional References: (to be updated)

Dr. Joel Cooper – thoracic surgeon who performed first ‘successful’ single and double lung transplants, known as the “Father of Lung Transplant“. The first actual lung transplant was performed in 1963 by Dr. James D. Hardy at the University of Mississippi in Jackson, MS.

Talking about Transplant with Dr. R. Duane Davis

Interview with Dr. R. Duane Davis, the Chief of Lung Transplant at Duke University

(Part of a series on the lung transplant program at Duke University in Durham, North Carolina)

Dr. R. Duane Davis is the Chief of the Lung Transplant Program at Duke, which is the second largest lung transplant program in the United States (after Cleveland Clinic which performed 154 transplants last year to Duke’s 117*). During my visit, surgeons performed their 70 & 71st transplant this year, and will probably complete around 140 transplants before the year’s end. Much of Duke’s success at becoming a high volume transplant center lays at the feet of Dr. Davis, who took over the program in 1994, after training with the famed Dr. Joel Cooper. However, he credits many of his achievements to his training with several pulmonologists. In fact, he reports that it was his collaborative efforts with pulmonologists that led to his initial observations regarding the frequency of gastric reflux among transplant patients. (Later this was translated into the seminal work on the relationship between reflux / aspiration and graft failure**.) He cites this as one of the more important recent discoveries in the field of lung transplantation.

He estimates that during his career (thus far) he has performed around 750 – 800 lung transplants, making him one of the world’s more prolific lung transplant surgeons.

Dr. Davis is also responsible for several decisions that have distinguished Duke among transplant programs.

One of these decisions was the elimination of upper age restrictions for recipients. Unlike many facilities, Duke does not limit eligibility for transplantation solely based on age. (Many facilities limit transplantation to patients in their mid-sixties or below.) As part of this, he also rejects much of the ageism that is often implicit in transplant. “If we have two patients, otherwise equally matched but one is 18-years-old and the other is 53, then everyone always wants to give the transplant to the 18-year-old,” he explains. “It’s ageism to do that, particularly when research shows that the 18-year-old may not do as well [due to risk of noncompliance with anti-rejection meds. etc] so we need to carefully consider all of the factors before deciding,” he continues. “It makes us all feel good to give it to the 18-year-old, but that’s not always the right decision.”

One of the other decisions is something we talked about in a previous post – the use of organs that other facilities have turned down, sight unseen. He credits this decision with the short waiting periods for Duke patients compared with other patients nationwide.

Dr. Davis explains this policy along with other efforts to expand the donor pool. “There will always be a larger demand than the supply, but by expanding our eligibility criteria we increase our likelihood of finding an organ for our patients. As Dr. Davis explains, using traditional criteria, only about 10,000 donors are available every year, and in this donor pool, only about 17% of donations are lungs. He believes this number should be at least 40%, and that many useful organs that could have been transplanted are discarded. This is why Duke often sends their procuring surgeon on site to examine the lungs personally before deciding to reject organs for transplantation, if the lungs are otherwise a good match; (by size, blood type, etc.). In an attempt to meet demand and extend the lives of patients that might not otherwise receive transplants due to the shortage of donors, Duke surgeons recently implemented a program to accept donors from cardiac death patients (where the heart has stopped beating.) In traditional donor criteria, the patient’s heart is still beating at the time of organ retrieval. However, this criteria severely restricts the amount of donors available. As part of his efforts towards these ends, he reminds people of the value that organ donation has to help others, and encourages people to become organ donors.

During the interview, he also talks about breakthroughs in transplantation, such as the double transplantation of Laura Margaret, a 16-year-old with an immune deficiency disorder (bubble boy disease) who received a double lung transplant, followed by a bone marrow transplant from the same donor. In particular, he sees this particular case as a gateway to future discoveries in preventing graft (organ) rejection.

Like most Lung transplant surgeons, transplantation is only part of what Dr. Davis does, he is also an accomplished cardiothoracic surgeon, and performs cardiac surgery (such as bypass surgery/ valve replacement and surgery for atrial fibrillation) routinely. He states that he doesn’t have a favorite procedure, but he does have a favorite scenario. “I love the Christmas transplant,” he explains, when a patient receives a transplant on or around the holidays, and I get to come out to the family after the operation, and tell them Merry Christmas.” It really is a wonderful gift for the patient, he finishes.

** Surprisingly, even very large centers such as John Hopkins (24 last year), Massachusetts General (16) and Mayo Clinic (16) perform less lung transplants that we might expect. Even UCLA only performed 50 lung transplants in 2010. (Information from Organ Procurement and Transplant Network). Like many thoracic procedures, (as mentioned during discussions on esophagectomy and other lung surgeries) better surgical outcomes are linked to high-volume centers. Whether this is a result of ‘practice makes perfect’ or is due to the fact that high volume centers like Cleveland Clinic and Duke are usually large academic centers with a wealth of resources is not entirely clear. However, I would advise patients to use caution before seeking organ transplant at a center that does only a few transplants per year (less than 20- 30.) A recent study by Weiss et. al (2009) at John Hopkins places this number at 20, which as Dr. Mathew Hartwig noted during a recent lecture, is coincidentally,the three-year average [number of lung transplants] at that center.

* Future article planned for this topic.

More about Laura Margaret:

Double lung transplant saves teen’s life

Pioneer transplant surgery

Laura Margaret story