Heart & Lung Transplant

Heart-lung transplantation (HLTx) is a surgical procedure for replacing failed heart and lungs. This type of dual transplantation is often coupled with technical complexity, leading to early post-operative complications and emphasizing the need for meticulous surgical planning and efficient teamwork. Also, according to the based-on-risk-benefit ratio, this type of surgery is only performed once the patient meets specific criteria. 

Common Conditions

• Congenital Cardiac Diseases With Eisenmenger Syndrome: This type of syndrome is caused by disruptions in the normal physiology of the heart. Congenital anatomic defects like holes create a shunt, directing blood from the left to the right side due to pressure differences, making the condition life-threatening.
• Pulmonary Hypertension Disorders:  Pulmonary hypertension is characterized by high blood pressure in the arteries that supply the lungs, resulting in an increased resistance to blood flow in the pulmonary circulation. This condition often coexists with various conditions, like lung and heart diseases, frequently leading to heart failure.
• Systemic Diseases: Conditions such as cystic fibrosis, along with lifestyle factors like smoking, can lead to both cardiac and pulmonary failure. Examples of these diseases include emphysema and ischemic heart disease.
• Idiopathic Pulmonary Fibrosis: Idiopathic pulmonary fibrosis (IPF) represents a progressive and typically fatal pulmonary ailment, with a median survival post-diagnosis ranging from 2 to 5 years. Patients suffering from IPF often bear a substantial load of comorbidities, notably cardiovascular disease (CVD), and exhibit overlapping risk factors that are also associated with CVD.

Symptoms of Heart and Lung Failure Requiring Transplant

The symptoms of heart and lung failure might vary depending on the type of underlying disease. Some of them are listed below:

• Shortness of breath
• Vigorous exertion or exercise at the initial phase
• Difficulty breathing when lying flat and needing extra pillows at night because of orthopnea 
• Waking up in the middle of the night with paroxysmal nocturnal dyspnea 
• Swelling of arms and legs (edema)
• Persistent coughing or wheezing
• Severe shortness of breath, restricting exercise and daily activities
• Recurrent pneumonia and excessive sputum production
• Cyanosis or bluish discoloration of the skin and lips

Criteria for Heart-Lung Transplant

Individuals eligible for a heart-lung transplant must meet the following criteria:

• Candidates for a heart-lung transplant should be under 55 years old and free of additional medical conditions, such as AIDS, diabetes, or hepatitis. 
• They should also be mentally sound and able to adhere to post-operative requirements, including exercise and immunosuppressant medication regimen.

Dual organ failure necessitating heart-lung transplants can result from:

• Primary cardiac disorder, precipitating pulmonary failure.
• Primary pulmonary disorder, precipitating cardiac failure.
• A systemic condition or congenital disabilities contributing to both cardiac and pulmonary failure

Patients with heart-lung failure might be candidates for multiorgan transplantation, mainly if they present with associated organ failures, such as advanced heart and lung disease, leading to pulmonary hypertension. However, these candidates must meet all heart-lung transplant criteria. Due to limited experience and insufficient outcome data, only established transplant centers proficient in each involved organ system will consider such complex procedures.

Contraindications

Listed below are the specific reasons why HLTx is not recommended:

• Active malignancy or a history of it within the last two to five years
• Active substance abuse, uncontrolled psychiatric disorders, non-compliance, poor functional status, or inadequate social support
• ABO incompatibility and positive crossmatch between donor and recipient
• A significant mismatch in donor-recipient lung size beyond 10% of the recipient’s height or weight
• Advanced age
• Previous thoracic surgery history
• Bilirubin levels of 2.1 mg/dL or higher, indicating advanced pulmonary hypertension and a potential need for a combined heart-lung-liver transplant

Complications

Complications following HLTx, as per the latest research, include:

• Primary graft dysfunction of the lung, which leads to severe hypercapnia and hypoxia 
• Primary cardiac graft failure, defined by sustained severe hemodynamic status without a clear explanation
• Acute airway emergencies
• Chronic rejection of the lung graft, resulting in bronchiolitis obliterans syndrome 
• Heart graft rejection, leading to coronary artery vasculopathy 
• Infections, especially fungal infections, accounting for up to 14% of cases of infectious complications 
• Medication-induced side effects, including hypertension, hyperlipidemia, diabetes, and renal dysfunction
• Post-transplant malignancies, such as post-transplant lymphoproliferative disorder (PTLD), have a higher incidence in heart-lung transplant recipients 
• Surgical complications, including injury to the vagal nerves (resulting in gastroparesis, reflux disease, and aspiration), phrenic nerve (manifesting as dyspnea), and thoracic duct

Advancements and Survival Rates in Heart-Lung Transplant

HLTx survival rates have significantly improved over time, showing marked gains in early post-transplant and long-term outcomes. These improvements stem from enhanced patient selection, surgical advancements, improved immunosuppressive therapies, and a deeper understanding of the associated risks. Listed below are the key points regarding survival rates post-procedure:

• Since the initial successful HLTx in 1981, close to 4000 patients have been subjected to this surgical intervention due to advancements in surgical techniques.
• The median survival for heart-lung transplant has increased over the years from 2.1 years (1982–1993) to 3.7 years (1994–2003) and 5.8 years (2004–2016). 
• Patients who survive the first year post-transplant can expect a median survival of 10.3 years. 
• Long-term survival rates were documented among early transplant recipients who survived beyond 1-year post-transplant.

HLTx is recommended as a surgical option for meticulously chosen patients. It presents optimal survival benefits for severe heart failure or complex coronary heart disease with pulmonary hypertension. Managing such complicated patients necessitates a multidisciplinary approach. It is crucial to closely monitor their declining function to ensure timely consideration for improving their survival rates.