Lung Transplantation (Lung Transplant)

Overview of Lung Transplantation

Lung transplantation is a widely recognized and lifesaving procedure aimed at bettering the lives of patients who suffer from severe respiratory failure that cannot be improved with other medical or surgical treatments. This important operation has been performed over 69,200 times for adults up until mid-2018, according to the international medical data. The survival rates of those who receive lung transplants are encouraging: 85% survive for at least one year, 68% for 3 years, and 55% for 5 years after the procedure, as per the United States health data.

Lung transplantation has significantly progressed since its inception. The first ever lung transplant was performed by Dr. James Hardy and his team at the University of Mississippi in 1963. Although the patient was not ideal because they had severe lung disease, advanced lung cancer, and kidney problems, this groundbreaking operation paved the road for future advancements. In 1981, the first successful combined heart and lung transplant occurred, representing another major leap in transplant surgery’s history.

In the past 60 years, there have been substantial improvements in lung transplantation. Especially over the last decade, thanks to better ways to use donor organs and improvements in how they are acquired. The number of patients being able to receive lung transplants has gone up, and patient outcomes have gotten better due to advances in medical and surgical management, as well as better understanding and care of microbes and the immune system. This progress has allowed more patients to be eligible for lung transplants and enhanced the success rates and overall outlook for patients undergoing the procedure.

Anatomy and Physiology of Lung Transplantation

The human body has two lungs, each with its own set of characteristics and roles. The central windpipe, or trachea, is connected to both the right and left lungs. Each lung has three surfaces – costal which is against the ribs, medial which is towards the middle, and inferior or diaphragmatic which is towards the diaphragm. Each lung is surrounded by a layer called pleura, which shields it. The right lung is generally shorter and wider than the left, filling up less space.

There are variations between the two lungs. The right lung is divided into three sections – upper, middle, and lower, while the left lung only has two sections – upper and lower, with an area called the ‘lingula’ as part of the upper section. The lungs are further divided into smaller, independently functional sections called bronchopulmonary segments, which have their own blood supply, nerves, and lymph vessels. The right lung has ten such segments, while the left has eight.

The lungs also have a root or “hilum,” located on the medial side, where critical body structures like blood vessels and bronchi enter and exit. The importance of these structures is stressed during surgical removal, or pneumonectomy, of the lung. The surgeon must correctly identify and treat these structures.

Depending on how much of the lung is removed, lung surgeries can be sorted into ‘anatomical’ or ‘nonanatomical.’ While ‘anatomical resections’ such as segmentectomy, lobectomy, or pneumonectomy involve removing whole lung sections, ‘nonanatomical resections’ like the wedge resection imply that only a smaller piece is taken.

Lungs for transplantation are usually procured from donors who have either been declared brain-dead or have a confirmed circulatory death. In the past, these lungs would be kept on ice during transportation to prevent them from deteriorating. But this method had its limitations and often led to exaggerated damage when blood supply and oxygen were restored. To overcome these challenges, technology has made possible ‘ex vivo lung perfusion’ (EVLP), which enables transporting, analyzing, and restoring donor lungs in a state close to body temperature. This method reduces damage and enhances the quality and viability of transplanted organs.

Why do People Need Lung Transplantation

Choosing who should receive a lung transplant requires careful thought to ensure the risks are minimized and the results are as optimal as possible. Timing the referral for the transplant is very important. To be a candidate for a lung transplant, a patient needs to be sick enough to need it but also healthy enough to withstand the surgery. The Lung Allocation Score (LAS) helps doctors determine which patients should get a lung transplant first by rating them on a scale from 0 to 100. This score is calculated based on 12 factors that impact the health and survival of patients with severe lung disease. The higher the score, the more urgently the patient needs a lung transplant. Research has shown that the LAS is better than doctors’ clinical judgement at predicting patient survival while waiting for a transplant.

Lung transplants are typically considered for adults with severe, chronic lung disease who, without a transplant, are likely to pass away from their disease within two years, but who are also likely to survive at least 90 days after the lung transplant and have a good chance of surviving at least 5 years after the transplant, assuming they don’t experience serious organ rejection.

One of the top reasons someone might need a lung transplant is because they have chronic obstructive pulmonary disease (COPD), which accounts for 40% of all lung transplants conducted globally. Another common reason for a lung transplant is cystic fibrosis, a genetic disorder which causes severe lung damage. It’s considered particularly for suitable patients with cystic fibrosis who have a 2-year predicted survival rate of less than 50% and have severe physical limitations. The third common reason is interstitial lung disease, specifically idiopathic pulmonary fibrosis, which carries the worst prognosis. The diagnosis usually indicates a poor outcome, with only 20% to 30% of patients living longer than 5 years after being diagnosed.

Doctors also consider lung transplantation for patients with pulmonary vascular disease, idiopathic pulmonary arterial hypertension, bronchiectasis, sarcoidosis, constrictive bronchiolitis, connective tissue diseases, and pulmonary hypertension because of congenital heart disease. The decision to list someone for a transplant depends on several factors. These include: how severe the disease is, how it affects the patient’s ability to compete in a test of how far they can walk in six minutes, whether they have hypertension in the lungs or right side of their heart, and the rate at which their health is declining.

When a Person Should Avoid Lung Transplantation

Lung transplantation is a complex treatment that’s high risk and can potentially lead to death during or after the procedure. Hence, it’s crucial to thoroughly evaluate each patient’s overall health and existing medical conditions to avoid complications. Although the points listed below highlight common concerns, they may not cover every possible medical scenario that could impact the transplant.

There are several clear-cut reasons, referred to as “absolute contraindications,” why a person can’t receive a lung transplant. These include:

• A recent history of cancer.
• Major organ system (like the heart, liver, kidney, or brain) not responding to treatment.
• Severe atherosclerosis, a condition where plaque builds up in the arteries leading to problems such as heart attack or stroke, that can’t be treated by improving blood flow through surgery.
• Immediate major health problems, such as severe infection throughout the body (sepsis), a recent heart attack, or liver failure.
• Uncontrollable bleeding disorder.
• Chronic infection with highly resistant or aggressive bacteria or viruses.
• A current active infection with Mycobacterium tuberculosis, bacteria that cause tuberculosis.
• Significant deformities of the chest wall or spine that would seriously limit lung movement after transplant.
• Obesity of class II or III (Body Mass Index, or how heavy you are relative to your height, of 35 or greater).
• Lack of that person’s ability to follow a medical treatment.

Also, psychiatric conditions that make it difficult for a person to communicate and work effectively with the medical team, stick to complex medication schedules, or a lack of proper and reliable support from friends or family can hinder the success of a lung transplant.

Sometimes, a person’s age or other medical conditions can make a lung transplant riskier but not impossible; these are known as “relative contraindications.” If you are one of these cases, the doctor would need to weigh the benefits and risks carefully:

• Being 65 or older with low physiological reserve (or a lack of strength and resilience).
• Class I obesity (Body Mass Index of 30-35), particularly if fat is concentrated around the waist.
• Severe malnutrition.
• Severe osteoporosis, a condition that weakens bones and makes them prone to fracture.
• Previous extensive chest surgery with lung removal.
• Infections with highly resistant or dangerous bacteria or viruses, including HIV.

Equipment used for Lung Transplantation

Recently, studies have shown that a technique called extracorporeal life support – a system that provides heart and lung support during surgery – has become an important method to manage lung functionality issues that occur after a lung transplant surgery. This technique is becoming more widely used to prevent and manage these issues globally. It’s also used in managing complex lung disorders before adopting this support system. A test known as a transesophageal echocardiogram, which is used to assess the function of the right side of the heart and detect high blood pressure in the lungs, is vital when using this support system efficiently before, during, and after the operation.

A new process called Ex Vivo Lung Perfusion (EVLP) has begun to show promise in addressing the shortage of donor organs. This method allows doctors to evaluate and potentially improve the quality of donor lungs that initially may not have been suitable for transplant. It also reduces risks related to long periods without blood supply caused by logistical issues. In the United States, the Food and Drug Administration has approved systems that use this technique, and these have shown promising results during trials. Past studies have suggested that the chances of survival after a transplant, for recipients of these so-called ‘marginal’ donor lungs improved by EVLP, are similar to those transplanted with lungs that were conventionally preserved and met standard criteria.

However, the widespread use of this technique has not increased much in the past few years due to the high costs associated with setting up EVLP programs. Current research is investigating ways EVLP could be used more broadly – like increasing the duration of organ preservation, improving the condition of initially unusable lungs, and enhancing the quality of already suitable lungs. As EVLP becomes more commonly used, these possible uses could be included in regular medical practice. This would allow for more donor organs to be available and could lead to improved outcomes for lung transplant patients.

Who is needed to perform Lung Transplantation?

The lung transplant process involves a team of different healthcare professionals who work together both inside and outside the operating room, all concentrating on making the transplant successful and ensuring the patient is well taken care of. The team inside the operating room involves:

• A cardiothoracic surgeon, a doctor who performs the lung transplant surgery.
• An anesthesiologist, a doctor who puts patients to sleep for the surgery and keeps a close eye on their vital signs while they are asleep.
• Surgical assistants, who provide help to the surgeon during the operation by handing over the instruments and other needs.
• Perfusionists, who operate the heart-lung machine used during the surgery.
• A circulating nurse, a medical professional who provides necessary help during the surgery.

Other important specialists involved in the lung transplant process include:

• A transplant pulmonologist, a lung doctor who supervises the condition of patients before and after the surgery.
• A transplantation cardiologist, a heart doctor who provides consultation on heart-related aspects of the transplant.
• A transplant nurse, who helps coordinate the care and acts as a link between the patient and the medical team.
• A physical therapist, who helps the patient regain their strength and ability to move after the surgery.
• A psychologist, who provides mental health support and helps the patient manage the emotional effects of the transplant.
• A social worker, who helps sort out social and practical needs such as arranging support services and counselling.
• Infectious disease specialists, doctors who help prevent and manage infections in the patients, who can be more susceptible to infections after the transplant because their immune system is suppressed to prevent rejection of the new lung.
• Hematologists, or blood doctors, who handle any issues related to blood that may arise during or after the procedure.
• Intervention counselors, who provide support for the patients in managing any changes in their behavior and substance use disorders.

All of these healthcare professionals work together as a unified healthcare team, to provide patients undergoing lung transplantation with complete care. This covers all their needs such as medical, surgical, psychological, as well as social, throughout their transplantation process.

Preparing for Lung Transplantation

Getting ready for lung transplant surgery involves a few key steps:

First, there’s a pre-surgery evaluation. This includes usual blood tests, a heart tracing (also known as an electrocardiogram or ECG), a special type of ultrasound called a TEE, and other imaging and diagnostic tests. The doctor will also review your medical history and do a physical examination.

Second, you will need to give your consent for the lung transplant surgery after understanding all the details and potential risks involved.

Third, the process of matching a donor lung to a recipient is a complex one. It starts with the donor’s age (whether they’re a child or an adult) and where the donor hospital is located. Donor lungs are then matched to patients who have the right blood type and size. The lung goes to the patient on the waiting list who has the highest LAS, a score that’s used to identify who needs the transplant the most and who is most likely to do well after the transplant.

Before the surgery, the patient is moved to the intensive care unit (ICU), where the medical team prepares them for the procedure. For those with more severe illnesses, doctors may use a machine called ECMO to help keep them stable until they can get a lung transplant.

The donated lungs are carefully reviewed. Their quality is assessed based on medical images, various tests, and the donor’s cause of death. In the hospital where the donation takes place, further checks are done. The lung is looked at again using a procedure called a bronchoscopy. Another physical check is done once the chest is opened. Doctors also review the levels of gases in the blood from all four veins in the lung before they agree the lung is fit for transplantation.

How is Lung Transplantation performed

A lung transplant surgery requires a lot of planning and involves many steps. When you’re in the operation room, the doctors will make sure you’re fully asleep with general anesthesia. Once you’re asleep, they will put a tube down your throat which will allow each lung to be ventilated separately. They will also put a catheter in your neck and leg for giving you medication and to monitor your heart rate and blood pressure during the surgery. If needed, these points can also provide the means to start specialized life support.

To watch your heart pump and check how your lungs are functioning, the medical team will use a special tool called a Swan-Ganz catheter. This device helps them understand your body’s dynamics during surgery in real-time.

For a lung transplant surgery, you’ll be placed flat on your back on the table, and the areas from your neck to your knee will be cleaned and sterilized properly.
The way the surgery is done depends on whether one or both lungs are being transplanted. For single lung transplants, the surgeon makes a cut on the side of your upper body. For double lung transplants, a larger cut across the chest is needed, similar to opening a clamshell. But nowadays, many doctors try to avoid making large cuts to reduce your discomfort and recovery time after surgery.

After the cuts are made, the surgeon will remove the sickest lung first. To do this, they have to carefully separate the lung from the chest cavity. Then, the blood vessels and bronchus (a passage that lets air in and out of the lung) are cut and prepared for the new lung.

At the same time, another team is preparing the new lung or lungs for transplant. The lung or lungs are kept cold to ensure that they stay healthy and viable for transplant. After the lung is ready, it’s attached to the bronchus and the blood vessels in your chest. This is done very carefully to make sure the lung is securely in place and airtight.

After the lung is attached, the medical team will gradually adjust the mechanical ventilator that helps you breathe to minimize the risk of injury to the newly transplanted lung.

After the surgery is over, tubes are inserted into different parts of your chest to drain fluids. These tubes help prevent complications after surgery. The cuts are then stitched up and bandaged.

Post-surgery, doctors exchange the double anesthetic tube to a single one, helping in normal breathing. Further, they’ll perform a bronchoscopy to check if everything is alright and suture lines are in place. A feeding tube will be inserted through the nose to maintain your nutritional needs while you recover.

After the operation, you’ll be taken to the intensive care unit (ICU), where your condition and the new lung will be carefully monitored and adjusted as needed. Pain control and anti-rejection medications will also be provided to ensure smooth recovery.

Once you are stable, physical therapy and exercises are initiated to help you regain strength and functionality. The whole process from the surgery to complete recovery is carefully managed by a team of specialized medical professionals to ensure your best health and well-being.

Possible Complications of Lung Transplantation

After a lung transplant, a patient might experience some complications. These can happen at different times – like right away (within 72 hours), soon after (within the first 3 months), a bit later (4 months to 1 year), or even much later (more than 1 year).

Right after the transplant, a patient might experience:

– Hyperacute rejection, which is a rare but serious condition where the body rapidly rejects the new lung. This could be because of certain antibodies in a patient’s blood that don’t match with the new lung.
– Donor-recipient mismatch, where the new lung isn’t a good match with the patient’s body. A good match depends on having compatible blood types and similar lung sizes, which is figured out using the patient’s height and age.
– Primary graft dysfunction, which is damage to the new lung caused by a lack of blood flow and then too much blood flow. This is a major issue that can lead to death soon after surgery or more complications later on. It’s assessed through a series of evaluations using X-rays and measuring the oxygen levels in the patient’s blood.

A few months after the transplant, a patient might face:

– Bleeding.
– Pleural complications, which are issues with the space between the lung and chest wall, like fluid buildup, blood buildup, air leaks, or a chylothorax which is a specific type of fluid buildup.
– Acute kidney injury.
– Acute rejection, where the body’s immune cells attack the new lung. This can start happening as early as one week after surgery and account for a small percentage of deaths within the first month after a lung transplant.

Over the medium term, between 4 months to 1 year post-surgery, a patient might experience:

– Acute rejection which can still occur, impacting up to 30% of patients in their first year after surgery.
– Airway complications, which might require a medical procedure using a tube passed down the throat, or further surgery.
– Vascular complications, or issues with blood vessels.
– Pulmonary thromboembolism, which is a dangerous condition where a blood clot blocks a vessel in the lungs.
– Infections, which can include those caused by viruses, bacteria, and fungi.
– Metabolic conditions such as high ammonia levels, diabetes, and heart disease.

After a year or more, patients might face:

– Chronic lung allograft dysfunction (CLAD), which is persistent lung damage. One type of CLAD blocks airflow and can happen in about 50% of patients within 5 years after transplant, usually surviving between 3-5 years after diagnosis. The other type of CLAD can damage the lung in a way that restricts its movement, and has a worse prognosis.
– Posttransplant lymphoproliferative disease, where immune cells that are supposed to control the body’s response to the transplant start to grow out of control.
– Recurrence of the original lung disease that required a transplant.
– Bronchogenic carcinoma, which is a type of lung cancer.

What Else Should I Know About Lung Transplantation?

Lung transplantation is a last resort treatment for patients suffering from serious lung disease. This treatment option becomes essential when all other medical and surgical treatments have not yielded the desired results. Today, more and more people are suffering from chronic lung diseases, and now with long-term lung damage due to COVID-19, there is an increasing demand for lung donors. Unfortunately, there is a shortage of donor organs, leading to an increase in death rates among those waiting for a lung transplant.

Recently, a new method called EVLP has emerged to deal with the shortage of donor lungs. EVLP allows doctors to test and prepare lungs from donors that might not have been used before and potentially increase the pool of usable organs for transplantation. This technique is particularly significant because of the limited number of ideal lung donors and the risks linked to extended time without blood supply during traditional methods of preservation.

Even though lung transplant procedures have been performed more frequently in recent years, the average survival rate for recipients from 2009 to 2016 is roughly 6.5 years. While enhancements in surgical techniques and care immediately after the surgery have greatly improved survival rates for the short-term, success in the long-term has not shown the same rate of improvement. This slowdown in long-term survival is mainly due to a condition called CLAD, which affects over 50% of lung transplant recipients within 5 years after the surgery. CLAD presents a major problem because there are currently no effective treatments to prevent or manage this condition, which greatly affects the long-term success of lung transplants.

In conclusion, lung transplantation remains an essential treatment option for patients with severe lung disease. While there have been improvements in short-term results, significant challenges still exist in this field. Rising demand and a shortage of donor lungs, as well as the impact of CLAD on long-term survival, emphasize the need for continued research and innovation. New advancements such as EVLP show promise in increasing the pool of donors and enhancing transplant success rates. However, more work is needed to address the root causes affecting long-term outcomes.