Safe pancreas transplantation in patients with coronary artery disease

Assessing Pancreas Transplant Candidate Cardiac Disease: Preoperative Protocol Development at a Rapidly Growing Transplant Program

Pancreas transplant rates, despite improving outcomes, have decreased over the past two decades. This is due, in part, to ageing, increasingly co-morbid pancreas transplant candidates. There is a paucity of published data regarding coronary artery disease (CAD) in this population. To inform peri-operative management strategies, we sought to understand the frequency of CAD among recipients of pancreas transplants at our center. Informed by these data, we sought to develop a standard protocol for evaluation. A retrospective review of pancreas transplants (solitary pancreas and simultaneous pancreas-kidney) was undertaken at the University of Maryland. Transplant outcomes and frequency of cardiac disease were analyzed. Current data were compared with historic controls. Over the study period, 59 patients underwent pancreas transplantation. Coronary architecture was assessed in 38 patients (64.4%). Discrete evidence of CAD was present in 28 of 39 patients (71.7%). All pancreas candidates (n = 21) who underwent left heart catheterization (LHC) demonstrated CAD (100%). No patients experienced myocardial infarction (MI) and no deaths resulted from cardiac disease in the early post-transplant period. Pancreas transplant candidates are at high risk for CAD. At a center in which pancreas transplant rates are increasing, a rigorous cardiac work up revealed that 71.7% of assessed recipients had CAD. Although asymptomatic, 6.8% required coronary artery bypass graft (CABG). Despite increasing age and co-morbid status, pancreas transplant recipients can enjoy excellent results if protocolized preoperative testing is used.

Predictors of 10-year pancreas allograft survival after simultaneous pancreas and kidney transplantation

OBJECTIVE

This study aimed to identify the preoperative, perioperative, and postoperative factors affecting 10-year pancreas allograft survival after simultaneous pancreas and kidney (SPK) transplantation.

METHODS

Analysis was performed on a prospectively maintained database of 56 SPK transplants consecutively performed between January 1992 and October 2002. The definition cutoff points of specific variables were obtained by the receiver operating characteristic curve and multiple logistic regression analyses that were performed to determine the predictors of pancreas allograft survival after 10 years.

RESULTS

In total, 44 (79%) patients had an overall survival of more than 10 years, and the overall 10-year pancreas allograft survival rate was 57% (n = 32/56). The significant predictors for pancreas allograft failure in 10 years and above were kidney allograft failure (P = 0.04), serum creatinine 1 year postoperatively (P = 0.002), and serum hemoglobin A1c (HbA1c) level 2 years postoperatively (P = 0.003). A serum creatinine cutoff value of more than 129 μmol/L at 1 year was 87.5% sensitive and 70% specific for predicting pancreas allograft failure at 10 years. Serum HbA1c of more than 5.6% at 2 years was 85.7% sensitive and 62.5% specific for predicting pancreas allograft failure at 10 years. On multivariate analysis, 129 μmol/L and above of serum creatinine and more than 5.6% of serum HbA1c were the independent predictors of pancreas allograft failure at 10 years.

CONCLUSIONS

These findings may provide important information for identifying patients at risk for long-term pancreas allograft failure after SPK transplantation.

[Role of simultaneous pancreas-kidney transplantation in the treatment of diabetes mellitus]

The life expectancy of patients with type 1 diabetes mellitus is inferior to that of patients with some malignancies. Simultaneous pancreas-kidney transplantation is the procedure providing the best survival results among all options of renal replacement therapy. The operative techniques and immunosuppresion have been standardized in the last decade. Although the number of transplantable organs falls behind the need, simultaneous pancreas-kidney transplantation is the method of choice for the eligible patients. The results of the two Hungarian simultaneous pancreas-kidney transplantation programs are in accordance with data published in the international literature.

Evolution of pancreas transplantation: long-term results and perspectives from a high-volume center

OBJECTIVE

To describe the evolution of pancreas transplantation from 1979 to 2011. The aim was to examine factors influencing long-term patient and graft survival, surgical methods, and risk factors influencing organ performance after transplantation.

BACKGROUND

Pancreas transplantation has become the therapy of choice for patients suffering insulin-dependent diabetes and end stage renal failure.

METHODS

Retrospective analysis of 509 consecutive pancreas transplants (442 simultaneous pancreas and kidney [SPK], 20 pancreas transplanted alone [PTA], and 47 pancreas transplanted after kidney [PAK]), performed at the University Hospital Innsbruck. The data were statistically analyzed using the Kaplan-Meier method and log-rank test.

RESULTS

After overcoming initial immunological and technical problems between 1979 and 1988 (5-year pancreas graft survival rate, 29.7%), pancreas transplantation evolved during the second decade (1989-1996; 5-year pancreas graft survival rate, 42.2%). Technical changes, optimized immunosuppression, careful pretransplant evaluation, and improved graft monitoring have become standard in the last decade and result in excellent 5-year patient (94.3%), kidney (89.4%), and pancreas (81.5%) graft survival. Five-year graft survival was superior in SPK (68.8%) compared with PAK (62.5%) and PTA (16.4%). SPK retransplantation can be carried out safely with 5-year patient (87.5%) and pancreas graft (75.0%) survival. Overall 5-year patient survival after loss of the first pancreas graft is significantly better in patients who underwent retransplantation (89.4% vs. 67.9%, P = 0.001). Long-term pancreas graft survival is independent of donor body mass index, sex, and cause of death, anastomosis time and the number of human leukocyte antigen (HLA) mismatches, recipient age, body mass index, sex, current panel reactive antibodies, and waiting time. Significant risk factors for reduced graft survival are cold ischemia time and donor age.

CONCLUSIONS

During the last 32 years, many problems in pancreas transplantation have been overcome and it may currently represent the therapeutic gold standard for some patients with diabetes and end stage renal failure.

Preemptive versus Non-preemptive simultaneous pancreas-kidney transplantation: a single-center, long-term, follow-up study

BACKGROUND

Data regarding the timing-before or after initiation of dialysis-of simultaneous pancreas-kidney transplantation (SPKT) in type 1 diabetes mellitus patients with end-stage renal failure are sparse. We studied the effect of preemptive transplantation on patient survival, cardiovascular endpoints, and graft survival, as compared with non-preemptive transplantation.

METHODS

All 180 SPKT recipients (aged 23-58 years) who received a SPKT in Leiden between December 1986 and May 2004 were included in the analysis. Sixty-five patients (36.1%) were transplanted preemptively. Mean follow-up time was 6.3 years.

RESULTS

Up to 8.2 years after transplantation, we found no differences in patient survival. Later on, divergence occurred: 10-year patient survival was 71.3% in the preemptive group versus 63.8% in the dialysis group and 15-year patient survival was 64.8% versus 45.1% in the dialysis group, leading to an adjusted hazard ratio for mortality of 0.50 (95% CI 0.23-1.06, P=0.070). Cause of death was less often of cardiac origin in the preemptive group (adjusted HR 0.16; 95% CI 0.026-0.95, P=0.044). Graft survival did not follow the same trend. No significant differences were found between the two groups considering allograft survival, cerebrovascular accident, or myocardial infarction. The percentage of patients with minor or major amputation(s) after transplantation was slightly lower in the preemptive group (24.6 vs. 32.1%; adjusted HR 0.87; 95% CI 0.42-1.82, P=0.72).

CONCLUSION

Preemptive SPKT offered a patient survival benefit as compared with transplantation performed while already on dialysis and was associated with a lower rate of cardiac deaths.

Incidence of coronary heart disease and cardiac events in patients undergoing kidney and pancreatic transplantation

One major cause of graft loss after kidney transplantation or simultaneous kidney and pancreas transplantation is death of the recipient due to cardiac events. Records of 261 patients who underwent sole kidney (group A) or combined kidney-pancreas transplantation (group B) were retrospectively analyzed. Patients were divided into groups with basic cardiac evaluation (chest X-ray, electrocardiogram) and patients with additional diagnostics [echocardiography, exercise stress test, myocardial perfusion test, and coronary angiography (CAG)]. The results of the performed CAGs were as follows: proven coronary artery disease (CAD) in 22 patients (12.43%) in group A and 37 patients (44.05%) in group B; stenosis of one main coronary artery of 70% or greater in 8.47% (group A) and 16.67% (group B) of the patients. Subsequent revascularization procedures were performed in 15 candidates (8.47%) of group A and 11 (13.10%) of group B. The incidence of posttransplant cardiac events (PCE) was lower in recipients in both groups who underwent additional cardiac evaluation. Late postoperative deaths were reported in 3.45% of kidney recipients with no additional evaluation (group A), in 2.06% of patients with further diagnostics (group A), and in only 1.19% of patients with invasive pretransplant evaluation (group B). Patients with known CAD and no further invasive diagnostics or subsequent revascularization are at great risk. PCE were observed in three of seven patients in this subgroup. Careful cardiac evaluation including echocardiography, exercise stress test, myocardial perfusion test, and CAG is associated with a low incidence of PCE.

Cardiac evaluation for simultaneous pancreas-kidney transplantation and incidence of cardiac perioperative complications: preliminary study

Type I diabetes mellitus (IDDM) is associated with an increased cardiovascular risk, and eligibility protocols for simultaneous pancreas-kidney transplantation (SPKT) are consequently accurate for preoperative cardiovascular assessment. According to our algorithm, coronary angiography in SPKT candidates is indicated for patients not only experiencing previous cardiac events or symptoms, but also those with long-standing diabetes (more than 25 years) and/or age over 45 years. Furthermore, a basal transthoracic echocardiographic exam (TTE) is performed to assess cardiac volumes, left ventricular mass, systolic function, and kinesis. The aims of this study were to evaluate perioperative cardiac morbidity and mortality in 18 SPKT-eligible patients, divided into two groups on the basis of the presence/absence of angiographically evident coronary artery disease (CAD), as well as to assess the impact of left ventricular hypertrophy (LVH) on cardiac complications. Cardiac intraoperative morbidity and mortality and postoperative mortality and major morbidity were absent; minor cardiac morbidity consisted only of silent ischemic ECG alterations, without significant differences between groups, although the incidence seemed to be higher in the CAD-positive population. LVH detected preoperatively by TTE exam also failed to correlate with the incidence of such complications. Selection of SPKT candidates by coronary angiography may have positive effects on perioperative cardiac morbidity and mortality. A larger sample size is needed to give the study statistical power. Medium- and long-term follow-up studies are warranted to evaluate the effects of preoperative selection on survival rates.

Lessons learned from more than 1,000 pancreas transplants at a single institution

OBJECTIVE

To determine outcome in diabetic pancreas transplant recipients according to risk factors and the surgical techniques and immunosuppressive protocols that evolved during a 33-year period at a single institution.

SUMMARY BACKGROUND DATA

Insulin-dependent diabetes mellitus is associated with a high incidence of management problems and secondary complications. Clinical pancreas transplantation began at the University of Minnesota in 1966, initially with a high failure rate, but outcome improved in parallel with other organ transplants. The authors retrospectively analyzed the factors associated with the increased success rate of pancreas transplants.

METHODS

From December 16, 1966, to March 31, 2000, the authors performed 1,194 pancreas transplants (111 from living donors; 191 retransplants): 498 simultaneous pancreas-kidney (SPK) and 1 simultaneous pancreas-liver transplant; 404 pancreas after kidney (PAK) transplants; and 291 pancreas transplants alone (PTA). The analyses were divided into five eras: era 0, 1966 to 1973 (n = 14), historical; era 1, 1978 to 1986 (n = 148), transition to cyclosporine for immunosuppression, multiple duct management techniques, and only solitary (PAK and PTA) transplants; era 2, 1986 to 1994 (n = 461), all categories (SPK, PAK, and PTA), predominantly bladder drainage for graft duct management, and primarily triple therapy (cyclosporine, azathioprine, and prednisone) for maintenance immunosuppression; era 3, 1994 to 1998 (n = 286), tacrolimus and mycophenolate mofetil used; and era 4, 1998 to 2000 (n = 275), use of daclizumab for induction immunosuppression, primarily enteric drainage for SPK transplants, pretransplant immunosuppression in candidates awaiting PTA.

RESULTS

Patient and primary cadaver pancreas graft functional (insulin-independence) survival rates at 1 year by category and era were as follows: SPK, era 2 (n = 214) versus eras 3 and 4 combined (n = 212), 85% and 64% versus 92% and 79%, respectively; PAK, era 1 (n = 36) versus 2 (n = 61) versus 3 (n = 84) versus 4 (n = 92), 86% and 17%, 98% and 59%, 98% and 76%, and 98% and 81%, respectively; in PTA, era 1 (n = 36) versus 2 (n = 72) versus 3 (n = 30) versus 4 (n = 40), 77% and 31%, 99% and 50%, 90% and 67%, and 100% and 88%, respectively. In eras 3 and 4 combined for primary cadaver SPK transplants, pancreas graft survival rates were significantly higher with bladder drainage (n = 136) than enteric drainage (n = 70), 82% versus 74% at 1 year (P =.03). Increasing recipient age had an adverse effect on outcome only in SPK recipients. Vascular disease was common (in eras 3 and 4, 27% of SPK recipients had a pretransplant myocardial infarction and 40% had a coronary artery bypass); those with no vascular disease had significantly higher patient and graft survival rates in the SPK and PAK categories. Living donor segmental pancreas transplants were associated with higher technically successful graft survival rates in each era, predominately solitary (PAK and PTA) in eras 1 and 2 and SPK in eras 3 and 4. Diabetic secondary complications were ameliorated in some recipients, and quality of life studies showed significant gains after the transplant in all recipient categories.

CONCLUSIONS

Patient and graft survival rates have significantly improved over time as surgical techniques and immunosuppressive protocols have evolved. Eventually, islet transplants will replace pancreas transplants for suitable candidates, but currently pancreas transplants can be applied and should be an option at all stages of diabetes. Early transplants are preferable for labile diabetes, but even patients with advanced complications can benefit.

Trends and perspectives in pancreas and simultaneous pancreas and kidney transplantation

Pancreas transplantation is still the best option to achieve normoglycaemia and insulin independence in patients with type I diabetes. As a result of improvements in surgical techniques, immunosuppression and patient selection, one year survival rates of 95, 83, and 88% for patient, pancreas, and kidney survival, respectively, are reported for patients with simultaneous pancreas and kidney transplantation. The main goals for the future are to reduce postoperative morbidity, to identify the relevant indications for single pancreas transplantation, to adopt the best surgical technique for individual patients' needs (bladder versus enteric drainage with or without portal venous delivery of insulin), and to develop immunosuppressive strategies with low nephrotoxic and diabetogenic potential.

Progression of macrovascular disease after transplantation

INTRODUCTION

Cardiovascular and cerebrovascular disease are major causes of morbidity and mortality after kidney transplantation. The aim of this longitudinal study was to examine the natural history of carotid plaque and to determine risk factors for the progression of vascular disease in uremic, type 1 diabetic patients who received a combined kidney and pancreas transplant.

METHODS

Carotid artery (n=765) and lower limb vascular duplex scanning (n=656) were prospectively undertaken in 82 recipients before transplantation, at 6 months, and then at annual intervals for up to 10 years. Plaque in the internal carotid artery (ICA), external carotid artery, and common carotid artery was classified by type, location, extent, and degree of functional obstruction, and evaluated using multivariate analysis.

RESULTS

Carotid plaque was present in 22.5% of patients at initial scanning, but increased to 56.6% by 7-10 years after transplantation, especially in the ICA and common carotid artery. Both the severity and extent of plaque increased, and plaque became more complex and heterogeneous with time after transplantation (P<0.001). Carotid plaque was associated with older age, current cigarette smoking, hyperphosphatemia, hypoalbuminemia, duration of pretransplantation dialysis, and presence of lower limb plaque (P<0.05-0.001). The severity of carotid plaque increased in older, hypertensive recipients and was associated with metabolic acidosis and hyperphosphatemia (all P<0.05). Severity of ICA disease correlated with disease in the contralateral ICA (r=0.57, P<0.001) and femoral arteries (r=0.42, P<0.001). Paradoxically, each carotid artery progressed independently of the other. ICA disease severity progressed when heterogenous, calcified, or new plaque was present on scanning, and with reduced renal transplant function (P<0.01-0.001). The mean ICA blood flow remained stable with time but was progressively impaired by hypertension, fasting hyperglycemia, and a lower prednisolone dose (P<0.05). Cerebrovascular events occurred in only four patients and were unrelated to carotid disease, implying relative plaque stability.

CONCLUSION

Extensive carotid vascular wall abnormalities increased significantly despite kidney and pancreas transplantation. Initiation of plaque was associated with systemic factors, whereas progression of established plaque was largely influenced by local factors within the arterial wall.

Mortality after vascularized pancreas transplantation

BACKGROUND

Previous studies have questioned the safety of vascularized pancreas transplantation (PTX), particularly because diabetes is an independent risk factor for coronary artery disease and cardiac death.

METHODS

A retrospective analysis of the timing and causes of death after PTX was performed. From April 1989 through December 1995, 196 PTXs were performed in 186 diabetic patients including 134 simultaneous kidney-PTXs, 59 solitary PTXs, and 3 combined liver-PTXs. All patients underwent whole organ PTX with bladder drainage, received triple or quadruple immunosuppression, and had a minimum follow-up of 1 year (mean 3.8 years).

RESULTS

A total of 22 patients (12%) died at a mean of 19 months after PTX. Infection was the most common cause of early death, whereas the majority of late deaths were due to cardiac causes. In the 8 deaths caused by infection, 6 were associated with operative complications, but only 2 received excessive immunosuppression for rejection. In the 10 cardiac deaths, 6 patients were older than 40 years at the time of PTX and 4 had experienced pancreas graft loss before death. Four-year actuarial patient survival was 92% after simultaneous kidney-PTX and 87% after solitary PTX.

CONCLUSIONS

In this series, the mortality rate after PTX was 12%, with infection, myocardial infarction, and sudden death accounting for over 80% of deaths. Deaths from infection most commonly occurred early and were associated with operative complications, whereas cardiac deaths usually were late and related to recipient age or preceded by pancreas graft loss. Future strategies aimed at reducing mortality after PTX should emphasize appropriate recipient selection and target prevention of operative complications.

What is the optimal approach for the end-stage diabetic nephropathy patient considering simultaneous pancreas-kidney transplantation?

This case-based discussion regards two very different patients with end-stage diabetic nephropathy (ESDN) who are considering transplantation. What is the best approach for each individual: pancreas-kidney transplant or kidney transplant alone? Suppose a live kidney donor is available? What are the risks and benefits of each approach? In the candidate evaluation process, medical issues, such as uncorrectable coronary artery disease, are investigated and may preclude transplantation altogether or dictate the optimal approach. Similarly, a careful psychosocial profile is important to tailor the approach to the patient. The multidisciplinary transplant team has an obligation to provide informed consent, foster realistic expectations, and advise the candidate based on collective expertise. Ultimately, the decision as to the best course-pancreas-kidney, kidney transplant alone, or no transplantation-is the result of a collaborative effort between the patient and the transplant team.

Pancreas and pancreas-kidney transplantation

Pancreas transplantation consistently results in an insulin-independent normoglycemic state in insulin-dependent diabetic recipients. Registry data show insulin independence is achieved in 80% of simultaneous kidney and pancreas recipients, more than 70% of pancreas after kidney recipients, and more than 60% of nonuremic pancreas transplant alone recipients. Advances in immunosuppression and careful monitoring for rejection in conjunction with biopsies are largely responsible for improved results. However, complications do occur, and improvements in surgical technique and patient care continue to evolve.