Small bowel transplantation: indications and prognosis

Small bowel transplantation is considered for chronic intestinal failure, when the patient's own intestines fail to absorb sufficient amounts of water, electrolytes, and nutrients, despite optimal rehabilitation and home parenteral nutrition. The most common causes are short bowel syndrome, severe motility disorders, and diffuse mucosal lesions. For adults and children, surgery is recommended only after consultation with a multidisciplinary team, as many patients can successfully resolve the problem without transplantation. [1]

Outcomes have improved in recent years, but it remains a rare, high-risk transplant requiring a specialized center. In 2023, 95 small bowel transplants were performed in the United States, up from 82 in 2022, but volumes remain low. The increase primarily affects adults, with the proportion of children declining due to improved rehabilitation. [2]

Home parenteral nutrition remains the primary method for maintaining life and quality of life in patients with benign causes of intestinal failure. Five-year survival rates with home parenteral nutrition in adults in large series reach approximately 70-80%, and are even higher in children. Therefore, transplantation is necessary for those who develop dangerous complications or who do not receive an acceptable quality of life. [3]

The position of modern guidelines is as follows: first, maximum possible intestinal rehabilitation, including nutritional optimization and drug approaches, then an assessment of the risks of home parenteral nutrition, and only in the case of a threat to life or an unacceptable risk of complications – referral for transplantation. [4]

When is a transplant really indicated?

The primary indications in adults and children are similar and include progressive liver disease associated with intestinal failure, multiple episodes of catheter-related infections, irreparable loss of venous access, uncontrolled dehydration with frequent hospitalizations, and rare malignant and non-malignant situations requiring multivisceral transplantation. In children, the most common causes are necrotizing enterocolitis and congenital anomalies, while in adults, resections due to ischemia and adhesive obstruction are more common. [5]

The decision to include the liver in the transplant is made in the presence of signs of liver failure due to long-term parenteral nutrition, portal hypertension, and severe cholestasis. This increases the chances of controlling immunological risks and reduces the likelihood of certain complications, but complicates the surgery. [6]

Contraindications include untreated infections, active malignant diseases outside the intestine, severe psychosocial limitations to adherence to therapy and rehabilitation, and severe multiple organ failure. Prior to listing, the standard included treatment of foci of infection, vaccination, and nutritional status correction. [7]

Adults with isolated intestinal failure without severe liver damage often undergo isolated small bowel transplantation, while those with liver failure often undergo combined intestinal and liver transplantation. Some patients require a multivisceral option, where other abdominal organs are transplanted along with the small intestine. [8]

Table 1. Clinical indications for small bowel transplantation

Situation	What's alarming	Why is this important?
Liver damage associated with intestinal failure	Rising bilirubin, hepatosplenomegaly, portal hypertension	Risk of liver failure without transplantation
Catheter infections	Repeated bacteremias in a short period of time	High mortality and loss of venous access
Loss of venous access	Central vein thrombosis	Inability to safely administer parenteral nutrition
Intolerable fluid loss	Frequent hospitalizations due to dehydration	Life-threatening and poor quality of life
Abdominal catastrophe or tumors	Irreparable anatomical problems	Indications for multivisceral transplantation
[9]

Transplant options and how to choose the type of surgery

There are four main types of surgery: isolated small bowel transplantation, combined small bowel and liver transplantation, multivisceral transplantation, and modified multivisceral transplantation. The choice depends on the cause of the failure, the condition of the liver, the presence of adhesions, and previous surgeries. [10]

Isolated transplantation is suitable for those with preserved liver function. Combined intestinal and liver transplantation is preferred for severe cholestasis and portal hypertension. Multivisceral transplantation is used for diffuse lesions of several abdominal organs, including the stomach and pancreas. [11]

In recent years, approaches to immunological risk stratification and the selection of induction regimens for different transplant types have been refined. This has allowed for better control of early rejections, although the frequency of biopsies and endoscopic monitoring remains high. [12]

An abdominal wall graft is sometimes used to cover the abdominal cavity in cases of severe tissue deficiency, but this is not necessary for everyone. The decision is made individually, taking into account safety and infection risks. [13]

Table 2. Graft types: comparison

Type	When choosing	Strengths	Restrictions
Isolated small intestine	The liver is intact	Less surgical trauma	Higher risk of lymphoproliferative complications
Small intestine with liver	Liver failure	Immune "protection" of the liver, fewer complications	A more complex operation
Multivisceral	Multiple organ involvement	Solving a complex problem	Longer surgery and recovery
Modified multivisceral	The composition needs to be “customized”	Precisely tailored to the clinical task	Limited availability of experience
[14]

Pre-transplant assessment and preparation

The assessment standard includes a nutritional audit, infection screening, venous access visualization, cardiopulmonary testing, immunological typing, and psychological assessment. Revaccination according to the schedule is mandatory, including prophylaxis against viral infections significant for recipients. [15]

It is important to consider the risk of catheter-related infections, thrombosis, and liver injury while on parenteral nutrition. Risk factors for an unfavorable outcome include a very short remnant of bowel, advanced age, frequent catheter-related infections, and progressive cholestasis. [16]

Pretransplant rehabilitation options include fluid optimization, catheter care training, and consideration of absorption-enhancing drug therapy. This approach can reduce dependence on parenteral nutrition and sometimes delay surgery. [17]

The decision to list is made collectively, balancing the prognosis with home parenteral nutrition with the expected risks of surgery and immunosuppression. The patient is informed about the frequency of endoscopies and biopsies in the early post-transplant period. [18]

Table 3. Pre-transplant checklist

Block	What to do	For what
Nutritional status	Correction of deficiencies, target protein and energy	Reduce postoperative complications
Infections	Screening and sanitation, vaccination	Reduce the risk of sepsis and reactivation
Venous access	Ultrasound and catheter planning	Ensure safe infusions
Immunology	Typing and risk of antibodies	Reduce the risk of rejection
Psychology	Assessing support and commitment	Improve rehabilitation outcomes
[19]

Surgery and the early postoperative period

The surgery involves vascular anastomoses with mesenteric vessels and usually the creation of an ileostomy for monitoring, followed by closure at a later date. Frequent endoscopic monitoring with targeted biopsies is necessary in the early weeks to detect rejection early. [20]

Typical early complications include bleeding, graft vessel thrombosis, anastomotic leakage, and sepsis. Success depends on the coordinated work of the surgical and intensive care teams and on early correction of hemodynamics and electrolytes. [21]

Enteral feeding begins as early as possible, as tolerated. Transition to full enteral autonomy takes weeks and months, requiring strict monitoring of fluid and electrolyte balance and nutritional markers. [22]

An ileostomy allows for safe observation of the mucosa and biopsy; once it stabilizes, it is closed. The timing depends on the patient's immunological status and anatomical conditions. [23]

Immunosuppression and infection prevention

Regimens typically include induction with antithymocyte globulin or alemtuzumab and maintenance therapy with tacrolimus and glucocorticosteroids, with mycophenolate sometimes added. Approaches depend on the type of transplant and immune risk, as well as on center protocols. [24]

Infection prevention is essential and includes strategies against cytomegalovirus, Pneumocystis pneumonia, and invasive mycoses, as well as monitoring for Epstein-Barr virus to reduce the risk of lymphoproliferative syndrome. Patient education on hygiene and risk management is critical to reducing early infection burden. [25]

The incidence of acute rejection in the first year after transplantation is lower today than previously, but remains significant. According to current registry data, approximately one-fifth of recipients experience an episode of acute rejection in the first year, requiring biopsy confirmation and intensive care. [26]

Lymphoproliferative complications are more common in isolated intestinal transplants than in liver transplants. This difference is explained by immunological factors and viral status, so risk stratification and monitoring are key. [27]

Table 4. Typical immunosuppression and prophylaxis regimens

Stage	Medicines	Target
Induction	Antithymocyte globulin or alemtuzumab	Reduce the risk of early rejection
Support	Tacrolimus plus glucocorticosteroids, sometimes mycophenolate	Long-term control of the immune response
Prevention	Antiviral, antifungal, prevention of Pneumocystis pneumonia	Reduce infectious complications
Monitoring	Endoscopies and biopsies, Epstein-Barr viral load	Early detection of rejection and lymphoproliferation
[28]

Results and forecast

According to national reports, 95 small bowel transplants were performed in 2023, an increase from 2022. The proportion of adults is increasing, and outcomes in children remain better than in adults for most endpoints. This reflects improved rehabilitation and candidate selection. [29]

For isolated transplantation in adults, median graft survival rates at 1 and 5 years are approximately 78% and 47%, while in children they are 76% and 52%. For combined transplantation with the liver in adults, the rates at 1 and 5 years are approximately 58% and 46%, while in children they are 81% and 60%. These figures illustrate the advantage of childhood and the complexity of adult cases. [30]

In the UK, volumes remain small over a ten-year period, and detailed five-year centre-by-centre evaluations are limited due to the rarity of the procedure. However, the report confirms the stability of the programmes and the comparability of results with countries with similar volumes. [31]

Retransplantation is associated with worse outcomes compared with primary surgery due to sensitization and cumulative complications. In large series, five-year survival after retransplantation is significantly lower, emphasizing the importance of preventing graft loss. [32]

Table 5. Key metrics based on current reports

Indicator	Meaning
US Operations for 2022	82
US Operations for 2023	95
Acute rejections in the first year	About 20% of patients
Five-year graft survival, isolated transplantation, adults	About 47%
Five-year transplant survival, intestine with liver, children	About 60%
[33]

Complications: what is most common?

Early surgical complications include bleeding, thrombosis, anastomotic leakage, and abdominal infection. Their prevention involves correct technique, careful hemodynamics, and early control of infection sources. [34]

Immunological complications include acute cellular and humoral rejection. Regular endoscopy with biopsies and rapid escalation of immunosuppression are required if the process is confirmed. Long-term monitoring of tacrolimus levels reduces the risk of relapse. [35]

Infectious risks remain the leading cause of hospitalization in the first year. The most dangerous are cytomegalovirus, invasive mycoses, and bacteremia. Prevention programs and patient education significantly reduce the incidence of severe complications. [36]

Lymphoproliferative complications associated with Epstein-Barr virus infection are more common in isolated intestinal transplants than in liver transplants, with a significant difference in five-year cumulative estimates. This necessitates monitoring viral load and cautious de-escalation of immunosuppression. [37]

Table 6. Common complications and key prevention

Complication	When to expect	Prevention
Thrombosis of graft vessels	The first days	Adequate antithrombotic tactics and monitoring
Acute rejections	First year	Induction, target tacrolimus levels, biopsy monitoring
Catheter infections	The entire period	Training, catheter locks, strict asepsis
Lymphoproliferation	Months and years	Monitoring of Epstein-Barr virus, optimization of immunosuppression
[38]

Transplantation or home parenteral nutrition: how to choose

A significant proportion of patients can achieve stability on home parenteral nutrition with an acceptable quality of life and manageable risks. Systematic reviews show that five-year survival rates are high for benign causes, and serious catheter infections are preventable with standard care. [39]

On the other hand, progressive liver damage, frequent bacteremia, persistent dehydration, and loss of venous access make surgery vital. In these scenarios, transplantation improves survival and fluid independence. [40]

Medication-assisted rehabilitation using glucagon-like peptide 2 analogues allows some patients to reduce infusion volumes and delay surgery. This effect has been confirmed by randomized and real-world studies, but requires candidate selection and safety monitoring. [41]

Quality of life after successful transplantation is generally improved in physical, emotional, and social domains compared to long-term parenteral nutrition, especially with complete enteral autonomy. This is an important consideration in shared decision-making. [42]

Table 7. Home parenteral nutrition and transplantation: a comparison

Criterion	Home parenteral nutrition	Small bowel transplantation
Survival in benign causes	High for 5 years	Lower on long horizons, but saves in case of life-threatening situations
Main risks	Catheter infections, thrombosis, liver damage	Rejection, infection, lymphoproliferation
Quality of life	Limited to infusions and catheter	Higher with autonomy from infusions
When is it preferable?	Stable flow without threats	In case of life-threatening complications
[43]

Children's characteristics

In children, the underlying cause is often necrotizing enterocolitis and congenital anomalies. Transplant survival in children is generally higher than in adults, especially in combination with liver transplantation. This is due to differences in the immune response and management. [44]

Transition to enteral autonomy in children after successful surgery and adequate rehabilitation is possible within months. Adequate enteral nutrition and reduced hospitalizations have a beneficial effect on growth and neurocognitive development. [45]

The key to success is early referral to specialized intestinal rehabilitation centers that can maximize recovery potential and delay or avoid transplantation in some patients. [46]

Issues of vaccination, monitoring of Epstein-Barr virus, and prevention of lymphoproliferation in children are particularly critical due to the high rate of primary seronegativity. Surveillance programs are age-adapted. [47]

Table 8. What to look for in children

Topic	Practical emphasis
Reasons	Necrotizing enterocolitis, atresia, congenital malformations
Tactics	Rehabilitation in a specialized center, early nutritional support
Infections	Vaccination and control of Epstein-Barr virus
Forecast	Higher chances of autonomy and transplant survival
[48]

Life after transplantation

The goal is complete or maximum enteral autonomy, gradual expansion of diet and physical activity. The patient is taught to recognize early signs of rejection and infection, adhere to the medication regimen, and attend scheduled endoscopies and biopsies. [49]

Most quality-of-life scales demonstrate improvement in psychoemotional and social parameters after successful surgery. Return to work and school is possible with stable graft function and reliable infection prevention. [50]

Follow-up visits are particularly frequent during the first year. Thereafter, intervals are increased, but viral monitoring and cancer screening continue on an ongoing basis. Correction of nutritional status and bone mineralization remains part of the standard plan. [51]

Long-term risks include chronic nephrotoxicity from tacrolimus, metabolic disturbances, and increased cancer risk. These are mitigated by individualized immunosuppression and regular screening. [52]

Disease codes for documentation

Proper coding is necessary for accounting and research. ICD-10-CM uses the following codes: K90.83 for intestinal failure, K90.82 and its refined variants for short bowel syndrome, including variants with preserved or absent connection with the colon. [53]

In ICD-11, short bowel syndrome is coded as DA96.04, and the neonatal variant as KB89.1. These codes help standardize clinical data and compare results between centers. [54]

Table 9. ICD-10-CM and ICD-11: Key Codes

Classification	Code	Name
ICD-10-CM	K90.83	Intestinal failure
ICD-10-CM	K90.82	Short bowel syndrome
ICD-10-CM	K90.821	Short bowel syndrome with preserved continuity with the colon
ICD-10-CM	K90.822	Short bowel syndrome without continuity with the colon
ICD-11	DA96.04	Short bowel syndrome
ICD-11	KB89.1	Short bowel syndrome in newborns
[55]

Questions patients ask most frequently

Is it possible to avoid surgery by reducing infusion volumes with medication?
Sometimes, yes. Glucagon-like peptide 2 analogs can reduce the need for infusions and delay transplantation in some patients, but the decision is always individual and depends on risks and tolerability. [56]

Is it true that transplantation is always "better" than home parenteral nutrition?
No. In stable and non-life-threatening conditions, home parenteral nutrition provides a high five-year survival rate. Surgery is indicated when there is a predicted threat to life or unacceptable complications. [57]

What are the chances of rejection in the first year?
Approximately one-fifth of recipients experience acute rejection in the first year, so close endoscopic and biochemical monitoring is necessary. [58]

What is the risk of lymphoproliferative complications and how are they prevented?
This is an oncological complication associated with the Epstein-Barr virus and the intensity of immunosuppression. Prevention includes risk stratification, viral load monitoring, and careful de-escalation of therapy at the first sign of a problem. [59]

Table 10. Brief decision-making roadmap

Step	Question	Action
1	Is stability achievable with home parenteral nutrition?	Optimizing rehabilitation and care
2	Is there a threat to life due to complications?	View listing
3	Is a liver needed as part of a transplant?	Assess liver function and portal hypertension
4	Is the patient ready for an immunosuppressive regimen?	Training and commitment assessment
5	Is there an opportunity in the center with experience?	Selecting a specialized program
[60]