Kidney Transplant

Overview

Kidney Transplantation is the preferred treatment for a small number of people with end-stage renal failure (ESRD). Kidney transplantation has evolved from a surgical, nephrology, and immunology experiment to the chosen method of renal replacement therapy for patients with end-stage renal illness.

For people with end-stage renal disease, kidney transplantation is frequently the chosen therapeutic option. Over the last 50 years, the field of kidney transplantation has expanded enormously. Patients with end-stage renal illness who are placed on a waiting list and finally receive kidney transplantation have a superior long-term survival rate than those who remain on dialysis.

What is Kidney Transplant?

One of the most common organ transplant operations performed today is a kidney transplant. Kidneys that aren't operating properly are replaced with a kidney from a donor during this operation. Kidney transplantation has been done since the 1950s. 

people who undergo transplantation frequently have a higher quality of life and a 10-year survival advantage over those who stay on dialysis. Dr. Joseph Murray conducted the first successful kidney transplant in 1954, and important advances in transplantation and immunology have allowed for a broader range of eligible donors and recipients.

Anatomy and Physiology

The kidneys are one of the body's paired retroperitoneal organs. The diaphragm, together with the 12th rib, abuts the kidneys superiorly and posteriorly. The right kidney is anteriorly bounded by the right colonic flexure, liver (hepatorenal ligament), duodenum, and pancreatic head.

The left kidney is bounded anterosuperiorly by the colon's splenic flexure, the splenic arteries, and the pancreas. The left kidney also has an anteromedial association with the spleen, which is linked by the lienorenal ligament. Both kidneys are located inferoposteriorly, on and close to the psoas muscle. The adrenal glands are located at the upper pole of both kidneys. The perinephric fascia, also known as Gerota's fascia, surrounds both kidneys.

The kidney's hilar structures are organized from anterior to posterior in the following sequence in the conventional anatomic position: renal vein, renal artery, and ureter/renal pelvis. To feed each kidney, the renal arteries branch from the aorta laterally right below the takeoff of the superior mesenteric artery. The right renal artery enters the body from behind the inferior vena cava.

The renal artery is then divided into anterior and posterior branches. The anterior division delivers 75% of the blood to the kidney, whereas the posterior division delivers 25%. The arterial divisions are divided into segments: the anterior division is divided into four segments: apical, upper, middle, and lower, and the posterior division is divided into the posterior segmental branch.

Because segmental arteries are terminal arteries, they do not exhibit collateralization. As a result, if they are wounded or obstructed, the parenchyma they feed is vulnerable to ischemia harm. Finally, continued branching of the segmental arteries produces interlobar arteries, arcuate arteries, and interlobular arteries.

The renal vein is often positioned prior to the renal artery. The venous plexus capillaries, like the arterial distribution, merge into arcuate veins, which subsequently drain into interlobular veins, trunks, and, lastly, the renal vein. Because of the vena cava's ipsilateral placement, the right renal vein is frequently small, empties directly into the cava, and has no tributaries. To reach the inferior vena cava, the left renal vein travels anterior to the aorta.

As a result, it is two to three times as lengthy as the right renal vein. The left renal vein, unlike the right renal vein, has several tributaries, including the gonadal vein, adrenal vein, inferior phrenic, lumbar, and paravertebral veins. It is worth noting that the SMA can be located anterior and superior to the left renal vein when it crosses the aorta. If all other factors are equal, the left kidney is preferable in living donation because to its additional length, which makes anastomosis technically simpler to execute.

Indications of Kidney Transplant 

End-stage renal disease (ESRD) is becoming more common. Diabetes and hypertension are the most prevalent causes of renal failure. Other causes of CKD/ESRD are classified as follows:

• Prerenal (chronic or acute ischemia),
• Intrinsic renal (glomerulonephritis), 
• Focal-segmental glomerulosclerosis, or 
• Postrenal categories (reflux nephropathy, obstruction). 

Patients who attain chronic kidney disease (CKD) stage 4, which corresponds to a GFR less than 30 mL/min/1.73 m, should consult a nephrologist and be informed about kidney failure and treatment options, including transplantation.

In the absence of transplant contraindications, the nephrologist will recommend the patient to a transplant facility while also initiating the appropriate procedures for potential dialysis commencement. There is a definite survival advantage for kidney transplant recipients versus dialysis patients. Furthermore, the duration of dialysis is an independent risk factor for worse results.

Contraindications of Kidney Transplant

Inability to endure surgery owing to severe cardiac or pulmonary illness, active malignancy, active infection, active drug misuse, and uncontrolled mental disorder are absolute contraindications to kidney transplantation.

Relative contraindications are more varied and can vary based on the institution and geographical region: morbid obesity with a BMI less than 40 kg/m, a history of noncompliance with dialysis schedule or drug regimen, fragility, psychological disorders, and a short life expectancy

Preparation for Kidney Transplant

• Patient Selection

The majority of ESRD patients have several co-morbidities and problems as a result of their renal illness. As a result, individuals are thoroughly examined for their ability to withstand surgery as well as the accompanying immunosuppression that comes with transplant surgery. The following is a summary of the comorbid condition evaluation:

• Cardiovascular Disease: Most ESRD patients require a thorough cardiovascular assessment, with noninvasive testing for those at high risk or experiencing symptoms. A dobutamine stress echocardiography, for example, has been demonstrated to have greater accuracy in predicting perioperative cardiac events. Cardiovascular disease is the major cause of mortality following kidney donation. As a result, if noninvasive testing reveals a positive result, these patients should have cardiac revascularization prior to transplant surgery.

• Cerebrovascular Disease: If a patient has a history of a cerebrovascular accident, including a transient ischemic stroke, he or she should be tested for carotid artery disease. A magnetic resonance angiography to test for aneurysms is also recommended if there is a history of polycystic kidney disease and concomitant symptoms. The femoral and pedal pulses should be felt. In the event of anomalies in the peripheral pulse exam, a history suggestive of PVD, and questions about sufficient iliac artery inflow, the desired location of implantation, further imaging (duplex US & CT) and possibly referral to vascular surgery should be explored. Any revascularization that is judged required should ideally take place prior to the transplant.

• Frailty: There are several frailty tests available to establish a candidate's suitability for transplant. The fragility test is a brief physical performance battery that yields an objective score. Unintentional weight loss, self-reported weariness, weakness (grip strength), poor walking speed, and limited physical activity are all areas of the Fried frailty criteria. These scales are very beneficial in the older population, particularly those above the age of 60.

• Gastrointestinal Disease: Anyone over the age of 50 who has a family or personal history of colon cancer or who is over the age of 50 should undergo a screening colonoscopy, according to USPSTF recommendations. Anyone suffering from active viral hepatitis or chronic liver disease should see a hepatologist about the possibility of a combined liver-kidney transplant.

• Hematologic Disorder: Patients having a history of thrombosis should be screened for hypercoagulable illnesses that may necessitate anticoagulant medication. A thorough coagulation panel should be performed on patients with bleeding diathesis.

• Infections: Active infection is a strict no-no for a kidney transplant. Most facilities will provide a thorough serology panel to screen for a variety of viral infections, TB, and other diseases. Vaccinations should also be current.

• Malignancy: To reduce the chance of post-transplant recurrence/metastasis exacerbated by immunosuppressive medication, most transplant facilities will need a cancer-free period of 2 to 5 years, depending on the kind of malignancy.

• Donor Selection/Allocation

There are two types of kidney donors: living or deceased.

Deceased donors are divided into two groups: those who are brain dead (DBD) and those who give after cardiac death (DCD). Brain dead donors, as the name implies, are individuals who have met the official criteria for brain death testing. DCD donors are people who, while not meeting the criteria for formal brain death, are regarded unlikely by neurologists to develop substantial neurologic recovery. In the event of DCD donation, procurement cannot commence until the heart has ceased beating and an impartial physician has declared the patient terminally extubated.

Even when paired kidney exchange, which entails organ travel before implantation, living kidney donation provides the highest graft and recipient survival. Ages 18 to 70 years, BMI less than 35 kg/m, no active cancer, no active infection, and good renal function (GFR > 80) are the current qualifying criteria.

BMI larger than 40 kg/m, diabetes, active malignancy, HIV positive, GFR less than 70 mL/min/1.72m, albuminuria, hypertension needing more than one drug, pelvic or horseshoe kidneys, and mental problems are absolute contraindications to living kidney donation.

Surgical Technique

Transplant surgery always entails two surgeries, one for the donor and one for the receiver. The procedure can be done minimally invasively or, less usually nowadays, with open surgery for the living donor. The kidney is implanted in the recipient in an open procedure, with the arteries anastomosing to the external iliac vasculature and the ureter anastomosing to the bladder. As the peritoneum retracts medially, the iliac vessels are preferentially exposed retroperitoneally. However, intra-peritoneal implantation is permissible as well.

Laparoscopic and/or robotic surgery are both minimally invasive procedures that can be utilized to get either kidney. Access to the intraperitoneal space is achieved in order to put a port. After the left colon is released from its peritoneal attachments and tracked cephalad to identify and isolate the renal vein and artery, the ureter and gonadal vein are identified at the pelvic brim for the left kidney. The adrenal gland is detached from the kidney's upper pole, and the adrenal vein is split.

Once the kidney has been fully mobilized and is only connected by the artery, vein, and ureter, a little bigger incision (typically the Pfannenstiel) is created to prepare for quick extraction. The distal ureter is separated by clips, and the hilar arteries are separated with a laparoscopic vascular-load stapler. There are certain changes in dissection depending on which kidney is obtained. To reach the right kidney, the liver is retracted and the right colon and duodenum are slightly mobilized. Following extraction, the organ is removed from the field and placed on the back-table for implantation.

An open surgical approach for living donor procurement involves making a subcostal incision and exposing the retroperitoneal region. Before extraction, the ureter is traced down to the iliac vessels and eventually separated there. When the recipient team is ready, the renal artery and vein are transected and the organ is transported to the back-bench. After that, the tributary stumps are ligated or oversewn. As the kidney is being prepped for implantation, any remaining perinephric fat is trimmed.

Organ Preservation

Once the kidneys have been obtained, they must be kept before being implanted. The kidneys suffer from ischemia throughout this procedure (and as soon as the donor's heart stops beating and normal circulatory perfusion is terminated). Cold ischemia begins when normal perfusion ceases and concludes until the kidney is reperfused in its recipient - the kidney should be on the ice for as much of this period as feasible to reduce metabolic demand and harm.

Warm ischemia is thought to be more damaging to the organ. It is traditionally referred to as the "sew-in" period, which begins when the organ is taken from cold storage and ends when it is reperfused following vascular anastomosis.

It is vital to note that there is an initial phase of warm ischemia in the DCD donation procedure between when the patient goes into cardiac arrest and the aorta is cannulated and flushed with the preservative solution and the organs are topically cooled with ice During cold ischemia, the organ is preserved in a static cold solution, which is widely used in the United States.

Organs can also be preserved by machine perfusion. This is a newer technique, and studies show that using pulsatile machine perfusion reduces the risk of delayed graft function. Machine perfusion ("the kidney pump") diagnostics may also be employed to test the organ's vascular patency, with special emphasis on flow and resistance. These objective criteria may help in organ selection, especially for DCD donors (blood is allowed to stagnate during circulatory stoppage until the flush is developed) and older donors with atherosclerotic disease.

Kidney transplant success rate

According to the August 2020 Scientific Registry of Transplant Recipients (SRTR) data, the 1-year national predicted survival rate for a live donor kidney transplant is 98.11 %. The dead donor transplant had a success rate of 94.88 %.

Kidney transplant recovery

Within eight weeks of their transplant, the majority of kidney transplant patients may return to work and other typical activities. Lifting anything weighing more than 10 pounds should be avoided, as should any exercise other than walking until the incision has healed (usually about six weeks after surgery). Maintain regular checks while you recuperate. 

Complication of Kidney Transplant

• Hemorrhage 

Hemorrhage is always a possibility during vascular surgery, both on the operating table and in the early postoperative period. Classical indications of bleeding may or may not be present. Because they are frequently on beta-blockers, patients may not exhibit conventional tachycardia in reaction to hypovolemia. Furthermore, due to parenchymal compression, they might be hypertensive rather than hypotensive.

They frequently report new-onset severe flank discomfort, and there may be a palpable lump or protrusion around the incision. A high level of clinical suspicion should be maintained, which may necessitate a return to the operating room. It's vital to remember that the kidney's segmented space in the retroperitoneum may tamponade bleeding, which would not be expected after intra-peritoneal implantation of the allograft.

• Thrombosis 

Renal vein thrombosis is thankfully uncommon, but it is linked with a significant risk of graft loss. This condition can emerge as new-onset hematuria, sudden-onset oliguria/anuria, and/or graft failure in the early postoperative phase. Arterial thrombosis is much rarer, yet it can be just as deadly and present identically in the receiver. Ultrasound is frequently diagnostic and should be conducted if the UOP of a previously functional allograft drops precipitously. Because to technical faults and/or clamp damage, a high level of suspicion for vascular problems should be maintained in the early postoperative period.

• Infection 

Infections are prevalent because patients are put on immunosuppression shortly after surgery. They are most immune-suppressed in the first 3-6 months after surgery, putting them at a higher risk of infection at that time. Conventional nosocomial and bacterial infections, such as UTIs and surgical site infections, are most frequent in the first month after transplantation (SSI)

A high level of suspicion should be maintained for unusual or opportunistic infections, especially in the months that follow. Cytomegalovirus, Epstein-Barr virus, and polyomavirus are among the most often examined viral infections. In the first 3-6 months, patients are frequently given preventive antivirals and antibiotics to reduce the chance of infection.

• Arterial Stenosis 

This is a late issue that is often asymptomatic. It is frequently discovered as a result of an ultrasonography check in the context of impaired graft function (elevated serum creatinine). Angiography can be used for both diagnostic and therapeutic purposes, and transluminal angioplasty can be undertaken.

• Lymphocele

This problem develops as a result of the disruption of related lymphatics during iliac vascular exposure. When feasible, careful ligation of lymphatic tissue should be performed during this dissection. Patients may have discomfort and swelling over the transplanted kidney. Alternatively, the collection might become contaminated, resulting in graft constriction and decreased function. Percutaneous drainage is used to treat symptomatic lymphoceles. To rule out a urine leak, the drain aspirate should be tested for fluid creatinine. Peritoneal window drainage can be used to treat persistent lymphocele.

• Urinoma 

This is most common within the first week following transplantation. Patients with lymphocele may have discomfort and edema near the incision, reduced graft function as a result of compression, or infection. In most cases, an increased creatinine level in the fluid aspirate supports the diagnosis. To prevent this complication as well as the delayed complication of ureteral stenosis, several centers put a ureteral stent at the moment of anastomosis. In the event of a urine leak, bladder decompression with the installation of a Foley catheter is usually all that is required. However, surgical intervention and ureteroneocystostomy correction may be required.

Kidney transplant cost

The average kidney transplant cost $442,500 in 2020. Charges for transplant admission, including surgery, are the most expensive line item, accounting for 34% of the entire cost.

Conclusion 

Kidney Transplant surgery is a significant procedure in which a person with kidney failure receives a new kidney from either a live or deceased donor. A successful kidney transplant is the closest thing to natural kidney function and is often regarded as the most effective treatment for ESRD, providing the opportunity for a longer, healthier life.

Transplantation is a multidisciplinary procedure. Patients are initially seen by nephrologists and hepatologists before being sent to a transplant surgeon. There are many additional stages before an organ is assigned once a referral is made and the patient is placed on a transplant list. When an organ becomes available, transplant coordinators assist in matching and assigning the organ.

After that, the patient is hospitalized for surgery, which is performed by surgeons, anesthesiologists, operating room technicians, and, later, critical care unit doctors, nurses, pharmacists, and social workers.