Evan Rotar and Leora Yarboro
Heart Procurement
The topic of thoracic organ procurement has been extensively described through consensus reviews, technical articles and videos, book chapters, and ultimately by word of mouth from attendings to trainees venturing on procurements. Our goal with this chapter is to address the following: general procurement conduct, key operative steps and technical considerations, and cardiac preservation techniques. We hope that this review serves both experienced and novice readers alike, be it reviewing for board examinations, or as a quick read en route to a donor hospital.
General Procurement Conduct
First and foremost, it must be reinforced that cardiac donation is a true gift of life from one person and their family to another. Demonstrating respect for the donor and their family should be of utmost importance, even in the setting of potentially stressful procurement efforts. This idea further evolves to the professionalism and collegiality that is critical for a well-timed and smooth procurement operation, especially when multiple surgery teams are involved and logistics are challenging.
Open communication with recipient hospital, other surgical teams, the donor hospital anesthesia team, transplant coordinators and even pilots is mandatory for a well-executed procurement with optimal timing. Furthermore, it is important to expect the unexpected, prepare, and have backup plans in place, especially if the situation dictates an urgent procurement of the thoracic organ(s). If planning cannot be made ahead of time, be flexible when the unforeseen does arise and communicate liberally with the recipient OR. Be smooth and deliberate with intraoperative actions as frantic moves endanger the organ and do little to make up any additional time.
Upon arrival to the donor hospital, search for any new information and review all existing information including: UNOS identifiers, ABO compatibility, local definition of brain death if not a donor after cardiac death (DCD), appropriate consents, historical data and hospital course, CT imaging if readily available, current vitals and recent trends, current ventilator settings and level of vasopressor support necessary, CVP, cardiac output, ejection fraction, and the latest labs and available trends. Report any new information or aberrancies to the recipient hospital. Review echocardiographic data and coronary angiography, especially if not already known. Assessment for donor coronary disease is essential, with lesions 50% or greater being considered significant. Coordinate with the operating room team and take note of what instruments are available. It is worth noting not every donor hospital has a sternal saw, and familiarity with a Lebsche sternal knife is valuable.
After reviewing all pertinent information and familiarizing yourself with the donor hospital, it is crucial to be in the room with the donor at all times. For brain death donors, optimizing several factors will significantly impact the quality of the organ including: cardiac filling pressure, end-organ perfusion pressure, protective ventilation strategies and the preservation of metabolic homeostasis. While efforts may be ongoing to achieve these aims, understand the level of acceptable perturbations in patient condition. Communicate the range of tolerable hemodynamic parameters and medication dosing to donor anesthesia team. If significant changes arise, communicate these to the recipient hospital team. If there is concern for depressed cardiac function, transesophageal echocardiography should be employed expeditiously for assessment.
Outcomes of an excellent transplant are dependent on excellent procurement. Everything to maximize protection of the donor organ should be employed or advocated for. Marginal donors and high-risk recipients have an even smaller tolerance for error. Organ ischemia is of always of critical concern and all efforts to minimize this time should be undertaken.
Operative Steps
Surgeon preferences and institutional protocols may differ regarding the timing or approach to donor cardiectomy. Here, we highlight the fundamental operative steps and important technical considerations. Please note that additional resources are referenced below. The goal in understanding the steps of the operation is to ensure optimal visualization for incisions, allow adequate delivery of protective perfusate, and prevent organ distention. Although arrhythmias may occur in up to 20-30% of donors, all measures to prevent them should be taken.
- Wide preparation and drape patient chin to knees
- Midline incision in continuity with ex-lap if applicable; be mindful of the liver
- Median sternotomy and development of pericardial well
- Position retractor with crossbar out of common workspace
- Visually inspect and palpate heart for anomalies that may have been missed. Relay any new discoveries, including normalcy, to recipient team.
- Divide the adventitial attachments between aorta and pulmonary artery (PA)
- Mobilize the superior vena cava (SVC) to the level of the innominate vein, separating from the right PA. Mobilize the inferior vena cava (IVC) from the pericardial reflection.
- Place pursestring sutures in aorta and PA (if lungs are also being procured). Heparin (400U/kg) is administered and a cardioplegia cannula is inserted.
- Timing of heparin administration should be coordinated amongst all procuring surgeons and recipient teams.
- Depending on the planned transplantation technique, ligate the SVC at the level of the innominate vein (bicaval technique) or 2-3 cm from the right atrium (standard right atrial cuff technique). Divide the IVC above the diaphragm and coordinate with Liver team if applicable. Vent the LA through the appendage, left atrial wall anterior to the left inferior pulmonary vein, or Waterston’s groove.
- Venting through Waterston’s groove allows for precise interatrial incision to be performed without visual obstruction by blood before cross-clamping aorta. Be aware that dissection of Waterston’s groove can initiate arrhythmias and should be performed with caution.
- Place a pool-tip sucker in IVC to prevent venous blood and abdominal perfusate from reaching the heart and warming the tissue.
- Ligating the SVC distal to azygos will avoid SA node injury.
- Cross clamp the aorta and administer cold cardioplegia. Administer topical cooling with ice slush.
- Do not place slush until confirmation of adequate perfusate infusion has begun with good pressure.
- Continually check aortic root pressure and assure prevention of LV distension while perfusate infuses.
- Divide the aorta at the level of the aortic arch, and the pulmonary artery at the level of the bifurcation.
- Elevate the heart from the pericardium and mobilize by dividing the pulmonary veins at the level of their pericardial reflection.
- In cases where the lungs are also being harvested, the LA is divided on the left at the midpoint between the coronary sinus and the pulmonary veins. This is the most contentious donor cuff, but the minimum acceptable LA cuff on the donor heart is 1.5cm. Of importance, resection of left atrium to pulmonary vein bifurcation can result in pulmonary venous outflow obstruction. Good communication should ensure both teams are satisfied with the outcome.
- Division of the LA wall should be performed under direct vision with Metzenbaum scissors.
- Once the heart is out, complete a timely but thorough inspection for: PFO, atrial or ventricular septal defects, valvular abnormalities, vascular injury, cuff length, endocarditis or intracardiac masses.
- Final preparation includes placing the heart in sterile bag of 1,000 mL of 4°C solution. Then place in a second bag with another 1000 mL of solution to protect against contact-mediated hypothermic injury.
Cardiac Protection
The key principles of donor cardiac protection include hypothermic arrest of metabolic activity, providing a physical and biochemical environment to maintain tissue viability, and minimization of reperfusion injury. Acceptable “safe” ischemic time is between 4-6 hours, but is dependent on quality of preservation. During procurement, ventricular distention must be avoided at all costs, and close monitoring of the heart during entirety of procurement cannot be overemphasized. During instillation of preservation solution, a root pressure of 60-70 mmHg should be adequate, with higher pressures risking injury to the coronary arteries. It is worthwhile to manually palpate the aortic root to mentally establish what a safe physiologic perfusion pressure is in the event no perfusate pressure monitoring exists.
The most common preservation technique is static cold flush with crystalloid. At 4°C, metabolic rate is approximately 10-12% of normal body temperature. Many preservation solutions and additives exist, yet none has demonstrated superiority for organ preservation. Typically, solutions are hyperkalemic resulting in depolarized cardiac arrest. Furthermore, they usually contain oncotic additives to maintain normal osmotic pressure and prevent tissue edema, buffers to prevent acidosis, Krebs cycle intermediates for energy metabolism, and reactive oxygen species scavengers.
Significant interest surrounds ex-vivo perfusion of donor hearts to augment the preservation strategy. Proposed benefits include improved donor-recipient matching, allowance of continuous flow of oxygenated blood and washout of toxic metabolites, avoidance of hypothermia, and the possibility of rehabilitating marginal organs. The PROCEED II trial examined ex-vivo perfusion utilizing the Organ Care System and demonstrated non-inferiority to standard cold preservation for all primary and secondary endpoints. Cardiac preservation with the Organ Care System yielded significantly longer mean preservation time and reduced cold ischemic time compared to standard cold preservation technique. The Organ Care System has further been employed by selected centers worldwide for preservation of DCD organs.
Suggested Readings
- Copeland H, Hayanga JWA, Neyrinck A, et al. Donor heart and lung procurement: a consensus statement [published correction appears in J Heart Lung Transplant 2020;39:734]. J Heart Lung Transplant. 2020;39:501-17
- Camp JR, PC. Heart Transplantation: Donor Operation for Heart and Lung Transplantation. Operative Techniques in Thoracic and Cardiovascular Surgery. 2010;15:125-37
- Connellan M, Dhital K. Donor Heart Procurement From the Donation after Circulatory Death Pathway. Operative Techniques in Thoracic and Cardiovascular Surgery. 2017;22:58-67
- Salerno CT, Verrier ED. “Heart Transplantation.” Mastery of Cardiothoracic Surgery, edited by Kaiser LR, Kron IL, and Spray TL. Lippincott Williams & Wilkins. 2014, 621-628.
- Kachroo P, Rove JY, Bribriesco AC, Taghavi S, Pasque CC, Pasque MK. Cardiothoracic Organ Procurement for Transplantation: How I Teach It. Ann Thorac Surg. 2016;102:1042-5
- Copeland H, Copeland J, Awori Hyanaga, JW. Cardiac and Pulmonary Donor Procurement. Curr Opin Organ Transplant. 2018;23:281-285
- Jacobs S, Rega F, Meyns B. Current Preservation Technology and Future Prospects of Thoracic Organs. Part 2: Heart. Curr Opin Organ Transplant. 2010;15:156-159
- Jahania MS, Sanchez JA, Narayan P, Lasley RD, Mentzer Jr RM. Heart Preservation for Transplantation: Principles and Strategies. Ann Thorac Surg. 1999;68:1983-7
