Exocrine Secretion in Simultaneous Kidney Pancreas Transplantation?

Robert J. Stratta, MD

Disclosures

December 14, 2000

Question

Our transplant service is beginning a simultaneous pancreas-kidney transplant program. How should we handle the exocrine secretion of pancreas, bladder, or ileoduodenal link?

A. I. David, MD

Response from Robert J. Stratta, MD

The decision regarding which technique of pancreas transplantation (PTX) to perform is an important one. The short answer is to perform whatever technique the surgeon or transplant team is most experienced or comfortable with. For programs that are starting out in PTX, it really depends on the training and experience of the surgeon(s). If the surgical team does not have formal training in PTX, then I would recommend that they pursue such training. In a perfect world, the surgeon(s) should have experience in all techniques of PTX, including systemic-bladder (S-B), systemic-enteric (S-E), and portal-enteric (P-E). I should preface this by stating that each of these techniques involves whole-organ pancreaticoduodenal transplantation with a variable length of donor duodenum transplanted with the pancreas.

I believe that the transplant should be done through a midline incision by means of an intraperitoneal approach and that the pancreas should be transplanted simultaneously with a kidney from the same donor. For new programs, I do not believe that they should start with solitary pancreas transplants (pancreas alone [PA], sequential pancreas after kidney [PAK]), but instead should restrict their activity initially to simultaneous kidney-PTX (SKPT). The perioperative management issues are more complex with solitary PTX, so these procedures should be performed only at centers that have an established track record and successful experience in SKPT. Furthermore, I believe that SKPT should only be performed at transplant centers that have an established track record and successful experience in kidney transplantation. PTX should only be performed by experienced transplant surgeons!

According to International Pancreas Transplant Registry (IPTR) data, over 14,000 PTXs have been performed worldwide from 1966 through July 20, 2000. In the United States, over 1200 PTXs are performed annually, with 83% being SKPTs. The current 1-year actuarial patient, kidney graft, and pancreas graft survival rates after SKPT in the United States in the most recent era (1996 to 1999) are 95%, 92%, and 84%, respectively.

Most PTXs are performed with systemic venous delivery of insulin (iliac vein drainage) and either bladder (S-B) or enteric (S-E) drainage of the exocrine secretions. From 1988 through 1995, more than 90% of PTXs were performed by the standard technique of S-B drainage. Because S-B drainage is safe, effective, time-tested, and mimics a kidney transplant procedure, most programs starting out find the transition to PTX easier by using this technique.

Bladder drainage by the duodenal segment technique became popular because it is safe, sterile, convenient, enables urinary monitoring of pancreatic secretions, affords access for cystoscopic biopsy, and permits easy control of anastomotic problems with urethral catheter drainage. However, this technique also creates a nonphysiologic connection between the allografted pancreas with a duodenal conduit and the urinary bladder that creates obligatory fluid and bicarbonate losses in the urine and alterations in the normally acidic, enzyme-free milieu of the lower genitourinary tract. Although well tolerated in most cases, bladder drainage has been associated with a finite rate of unique metabolic and urologic complications resulting from altered physiology. When these complications become intractable, conversion from bladder to enteric drainage (enteric conversion) may be therapeutic. Enteric conversion rates range from 10% to 25% in most large series. According to IPTR data, the rate of enteric conversion is 7% at 1 year and 11% at 2 years after PTX with bladder drainage.

Because of a favorable experience with enteric conversion, coupled with advances in preservation, donor selection, and immunosuppression that place the duodenal segment at a lower risk for ischemic or immunologic injury, there is renewed interest in avoiding the unique complications of bladder drainage by performing primary enteric drainage of the exocrine secretions. Since 1995, the number of PTX procedures performed with primary enteric drainage has steadily increased, accounting for 60% of cases in 1999. Initially, most cases of enteric drainage were performed with a diverting Roux-en-Y limb. More recently, the majority of cases with primary enteric drainage are being performed successfully with a side-to-side duodenoenterostomy. According to IPTR data, the 1-year results of SKPT are similar for S-B (bladder) and S-E (enteric) drainage, 85% and 84%, respectively, for cases performed from 1996 to 1999. Similarly, for cases of primary enteric drainage, the 1-year results are comparable with or without a diverting Roux limb. Consequently, at many experienced PTX centers, there has been a trend away from bladder drainage and a trend away from using a diverting Roux limb in order to simplify the surgical procedure.

Despite an evolution in surgical techniques, the majority of PTXs are performed with systemic (iliac) venous delivery of insulin (S-B, S-E drainage). To further improve the physiology of PTX and to avoid the potential complications of systemic hyperinsulinemia (such as dyslipidemia, accelerated atherosclerosis, and insulin resistance), another technique of PTX was developed with portal venous delivery of insulin and enteric drainage of the exocrine secretions (P-E). However, the proportion of cases with P-E drainage has remained low and represents only 15% to 20% of enteric-drained PTXs reported to the IPTR. In the most recent IPTR analysis including PTXs performed between 1996 and 1999, the 1-year pancreas graft survival rates were similar for P-E and S-E drainage, 83% and 84%, respectively. Recent prospective trials comparing the various techniques have concluded that each of them should be included in the repertoire of PTX. Depending on the individual case and anatomy, one technique may have specific advantages over the others. In composite, however, equivalent short-term results can be attained with each technique. The preferred technique may ultimately be determined by long-term studies investigating nonsurgical issues such as physiologic, immunologic, and metabolic aspects of the procedure.

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