Heart transplantation surgical procedure
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Editor(s)-in-Chief: C. Michael Gibson, M.S., M.D.; Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [1]Ifrah Fatima, M.B.B.S[2] Edzel Lorraine Co, DMD, MD[3]
Overview
Surgery is usually reserved for patients with advanced, irreversible heart failure with a severely limited life expectancy. Surgery is not the first-line treatment option for patients with heart failure. The mainstay of treatment for heart failure is medical/device therapy.
Indications
- Surgery is the first-line treatment option for patients with either:
Systolic Heart Failure with a Left Ventricular Ejection Fraction less than 35%
- Due to either:
- Ischemic cardiomyopathy
- Dilated cardiomyopathy
- Valvular heart disease
- Hypertensive heart disease
- Etiologies which are excluded are amyloid, HIV, and cardiac sarcoma
Ischemic Coronary Artery Disease with Refractory Angina
- Ischemia which is not amenable to percutaneous or surgical revascularization (coronary artery bypass graft surgery CABG) and is refractory to maximally tolerated medical and/or device therapy. [2]
Intractable life-threatening Arrhythmias
- Ventricular arrhythmias which are not controlled by an implantable cardioverter-defibrillator and are refractory or not amenable to electrophysiologic guided single or combination medical therapy
- Patients that are not a candidate for catheter ablation therapy. [3]
Cardiomyopathies
- Restrictive and Hypertrophic Cardiomyopathies with NYHA Class IV heart failure symptoms that persist despite maximal medical therapy, myomectomy, alcohol septal ablation, mitral valve replacement
- Non-dilated cardiomyopathies such as arrhythmogenic right ventricular cardiomyopathy. [3]
Congenital Heart Disease
- CHD resulting in New York Heart Association functional class IV Heart Failure not amenable to surgery.
- Severe symptomatic cyanotic congenital heart disease.
- Presence of some degree of pulmonary hypertension with the potential risk of developing fixed and irreversible elevation of pulmonary vascular resistance (PVR) [4]
Surgery
- The feasibility of surgery depends on the patient meeting the criteria for a heart transplant and also the risk-benefit ratio.
Pre-operative Procedure
Heart transplantation needs a donor heart from a recently deceased or brain dead donor. The transplant patient is then thoroughly evaluated for the operation. The donor heart is also evaluated to check its suitability for transplantation.
Operative Procedure
Once the donor heart has passed its inspection, the patient is taken into the operating theatre and given a general anesthetic. Either an orthotopic or a heterotopic procedure is followed, depending on the condition of the patient and the donor heart. [5]
Orthotopic Procedure
In the orthotopic procedure a median sternotomy is done to expose the mediastinum. After opening the pericardium, the great vessels including the superior vena cava, inferior vena cava, pulmonary artery, pulmonary vein and aorta are dissected and cardiopulmonary bypass is attached. The diseased heart is taken out after transecting the great vessels and a part of the left atrium. The pulmonary veins are not transected; rather a circular portion of the left atrium containing the pulmonary veins is left in place. The donor heart is now fit onto the patient's remaining left atrium and great vessels. The transplanted heart is started after slowly weaning the patient from cardiopulmonary bypass. The procedure is completed by closing the chest cavity. [6] [7]
Heterotopic procedure
In the heterotopic procedure, the diseased heart is left in place and the donor heart is implanted. The donor heart is placed in a way to have the chambers and blood vessels of both hearts connected. This results in something to the effect of a 'double heart'. In this way, the patient's original heart can be given a chance to recover. Therefore, even if the donor heart fails, it is removed to allow the patient's original heart to start working again. Heterotopic procedure is advantageous when the donor heart is not strong enough to function independently. This may be due to various reasons such as disproportionate body size of the patient and donor, the donor heart being weak, or pulmonary hypertension in the patient.[8] [7]
Post-Operative
Post-operatively the patient requires ICU care. The following are essential in a post-transplant patient:
- Adherence to post-operative immunosuppressive medications
- Precautions against infections.
- Rehabilitation
- Emotional support.
Another post-operative change to expect is mild tachycardia of around 100 bpm because the vagus nerve is severed during transplantation.
Living organ transplant
- In February 2006, at Bad Oeynhausen Clinic for Thorax and Cardiovascular Surgery, Germany, a 'beating heart' was transplanted into a patient.[9]
- The donor heart is kept at body temperature and connected to a Organ Care System. This machine lets it to continue beating with oxygenated blood flowing through it. This ensures that the heart remains in a suitable condition for a longer time.
Contraindications
Absolute Contraindications
- Patients who have a systemic illness with a life expectancy of less than 2 years despite undergoing a HT, including
- Active or recent solid organ or blood malignancy in the last 5 years
- AIDS with a history of frequent opportunistic infections
- Active multisystem diseases like- systemic lupus erythematosus, sarcoidosis, or amyloidosis
- End-stage or irreversible renal or hepatic dysfunction
- Significant obstructive pulmonary disease
- Fixed or irreversible pulmonary hypertension
- Pulmonary artery systolic pressure >60 mm Hg
- Mean transpulmonary gradient >15 mm Hg
- Pulmonary vascular resistance >6 Wood units
Relative Contraindications due to associated comorbidities
- Age - Patients are considered for cardiac transplant if they are < 70 years of age; or carefully selected patients over age 70.
- Obesity- BMI > 35 kg/m 2 is associated with a worse outcome.
- Cancer- Careful assessment of each neoplasm with a collaboration with oncology specialists to stratify each patient must be done. [12]
- Diabetes- End-organ damage and persistent poor glycemic control (glycosylated hemoglobin [HbA 1c] > 7.5% or 58 mmol/mol) are relative contraindications
- Renal dysfunction- Irreversible renal dysfunction ( eGFR < 30 ml/min/1.73 m 2) is a relative contraindication
- Peripheral vascular disease- Clinically severe symptomatic cerebrovascular disease may be considered a contraindication.
- Infections- Use of immunosuppressive therapy post-transplantation may cause a flare up of active infections.
- Human immunodeficiency viral (HIV) infection
- Chagas disease
- Tuberculosis
- Hepatitis B and C viral (HBV and HCV) infections
- Tobacco use- Active tobacco smoking is a relative contraindication.
- Substance Abuse- Active substance abusers (including alcohol) cannot receive a heart transplant.
- Psychosocial evaluation- Lack of social support of presence of cognitive disability are relative contraindications.
Cardiac Transplantation (DO NOT EDIT) [13][14][15][16]
| Class I |
| "1. For selected patients with advanced HF despite GDMT, cardiac transplantation is indicated to improve survival and QOL. [17][18][19] (Level of Evidence: C-LD) " |