Peri-operative cardiac morbidity in kidney transplant recipients: incidence and risk factors

BACKGROUND

Renal transplant recipients are known to be at increased risk for developing cardiac disease. In both general and peripheral vascular surgery, pre-operative risk stratification (and intervention when indicated) has decreased the incidence of peri-operative cardiac complications. In this study, we set out to identify subsets of patients at high risk for peri-operative cardiac complications after a renal transplant.

METHODS

We retrospectively reviewed the records of 2694 adult renal transplants performed at the University of Minnesota between January 1, 1985 and December 31, 1998. We determined the incidence of peri-operative (within 30 d post-transplant) cardiac complications, including myocardial infarction (MI). Risk factors for the development of these complications were determined by multivariate analysis.

RESULTS

We found 163 peri-operative cardiac complications, for an overall incidence of 6.1%. Specific cardiac complications included MI (n=43, 1.6%), arrhythmia (n=74, 2.7%), angina (n=31, 1.2%), cardiac arrest (n=13, 0.5%), and congestive heart failure (n= 2, 0.1%). By multivariate analysis, significant risk factors for any cardiac complication were age> or =50 yr (relative risk (RR)=3.0, p=0.0001) and pre-transplant cardiac disease (RR=3.3, p=0.0001). Not significant were diabetes mellitus (DM), cadaver donor source, pre-transplant dialysis, a history of smoking, and hypertension. Significant risk factors for peri-operative MI were age> or =50 yr, pre-existing cardiac disease, and DM. Diabetic patients with pre-existing cardiac disease were at especially high risk for peri-operative cardiac events.

CONCLUSIONS

Patients>50 yr and those with pre-existing cardiac disease, especially if diabetic, are at significantly increased risk for developing peri-operative cardiac complications after a renal transplant. Such patients require aggressive pre-operative investigations, which may include coronary angiography, to decrease the risk of post-transplant complications.

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.

Kidney retransplants after initial graft loss to vascular thrombosis

BACKGROUND

Vascular thrombosis early after a kidney transplant is an infrequent but devastating complication. Often, no cause is found. These recipients are generally felt to be good candidates for a retransplant. However, their ideal care at the time of the retransplant and their outcomes have not been well documented. We studied outcomes in 16 retransplant recipients who had lost their first graft early posttransplant (< 1 month) to vascular thrombosis.

METHODS

Of 2,003 kidney transplants between I January 1984 and 30 September 1998, we identified 32 recipients who had lost their first graft early posttransplant to vascular thrombosis. Of these 32 recipients, 16 were subsequently retransplanted and detailed chart reviews were done.

RESULTS

Of the 16 retransplant recipients, 12 lost their first graft to renal vein thrombosis and 4 to renal artery thrombosis. Thrombosis generally occurred early (mean, 3.6 d). Five recipients underwent a complete hematologic workup to rule out a thrombophilic disorder before their retransplant: 4 had a positive result (presence of antiphospholipid antibodies, n = 3; increased homocysteine levels, n = 1). These 4 recipients, along with 1 other recipient who had a strong family history of thrombosis, underwent thrombosis prophylaxis at the time of their retransplant. Prophylaxis consisted of low-dose heparin for the first 3-5 d posttransplant, followed by acetylsalicylic acid or Coumadin. Of the 16 retransplant recipients, none developed thrombosis. Of the 5 who underwent thrombosis prophylaxis, none had significant bleeding complications. At a mean follow-up of 5.4 yr, 10 (63%) recipients have functioning grafts. Causes of graft loss in the remaining 6 recipients were death with function (n = 5, 31%) and acute rejection (n = 1.6%). Graft and patient survival rates after these 16 retransplants were equivalent to results after primary transplants. The incidence of acute and chronic rejection was also no different (p = ns).

CONCLUSION

Vascular thrombosis in the absence of obvious technical factors should prompt a workup for a thrombophilic disorder before a retransplant. Recipients with an identified disorder should undergo prophylaxis at the time of the retransplant. Results in these retransplant recipients are equivalent to those seen in primary transplant recipients.

Pre-emptive transplants for patients with renal failure: an argument against waiting until dialysis

BACKGROUND

Pre-emptive kidney transplants have not been favored in some centers because of concern about possible increased noncompliance and allegedly inferior long-term results. We analyzed our experience with pre-emptive kidney transplants to determine whether such concerns are justified.

PATIENTS AND METHODS

Between January 1, 1984, and June 30, 1998, we performed 1849 adult primary kidney transplants: 385 pre-emptive (recipients not undergoing dialysis, ND) and 1464 non-pre-emptive (recipients undergoing dialysis, D). Results were subdivided by donor source: cadaver (CAD) and living donor (LD). ND recipients tended to be younger, but otherwise, the two groups were similar. Posttransplantation quality of life in recipients was evaluated using the nationally standardized Short Form Health Survey (SF-36). The posttransplantation employment status of the recipients was also evaluated.

RESULTS

The patient survival rate 5 years posttransplantation was significantly better for ND (vs. D) recipients for both CAD (92.6% vs. 76.6%, P=0.001) and LD (93.3% vs. 89.5%, P=0.02) transplants. The 5-year patient survival rate was significantly higher for ND recipients compared with recipients undergoing dialysis for < 1, 1-2, and > 2 years pretransplantation for both CAD (P=0.0005) and LD (P=0.0001) transplants. The graft survival rate 5 years posttransplantation was similar between ND and D recipients for CAD transplants, but significantly better for ND (vs. D) recipients of LD transplants (92.3% vs. 84.8%, P=0.006). For CAD transplants, the 5-year graft survival rate was not different when ND recipients were compared with recipients undergoing dialysis for < 1, 1-2, and > 2 years pretransplantation; for LD transplants it was significantly higher for ND recipients compared with recipients undergoing dialysis for < 1, 1-2, and > 2 years pretransplantation (P=0.04). The incidence of acute and chronic rejection was no different between ND and D recipients for either CAD or LD transplants, and it was also not affected by the pretransplantation time undergoing dialysis. Graft loss secondary to the recipient's discontinuation of immunosuppressive therapy (a crude estimate of compliance) was similar between ND and D recipients. Five years posttransplantation, the SF-36 scores regarding the recipient's quality of life and the employment status were similar for ND compared with D recipients, regardless of donor source.

CONCLUSIONS

ND recipients do not seem to have higher rates of noncompliance than D recipients. Results for ND recipients seem to be superior than for D recipients, supporting the contention that renal failure patients should, if possible, undergo transplantation before dialysis.

Increased incidence of cardiac complications in kidney transplant recipients with cytomegalovirus disease

BACKGROUND

The transplant literature has not shown cytomegalovirus (CMV) disease to be a significant risk factor for posttransplant cardiac complications. A large number of nontransplant studies have, however, reported an association between coronary heart disease (CHD) and CMV disease. Pathology studies have demonstrated a high incidence of CMV in atheromatous plaques from the coronary circulation.

METHODS

We performed multivariate analysis to determine if posttransplant CMV disease was a significant risk factor for cardiac complications in kidney transplant recipients. We also performed univariate analysis to determine which cardiac complications were more common in the recipients with CMV disease.

RESULTS

Between January 1, 1984 and June 30, 1997, 1859 adults underwent kidney transplants at our institution. Of these, 377 developed one of the following cardiac complications posttransplant: myocardial infarction, angina, arrhythmia, congestive heart failure, and angiographic vessel occlusion. By multivariate analysis, significant risk factors for one of the above cardiac complications were recipient age >50 years [odds ratio (OR)=2.5, P=0.0001], diabetes (OR=1.99, P=0.0001), a history of cardiac disease pretransplant (OR= 1.34, P=0.04), and CMV disease (OR=1.5, P=0.01). Univariate analysis demonstrated that recipients with CMV disease had a higher overall incidence of cardiac complications. Arrhythmias, congestive heart failure, and vessel occlusion were more common in those with CMV disease. The incidence of myocardial infarction, angina, and cardiac arrest did not differ between the two groups (recipients with versus without CMV disease).

CONCLUSIONS

CMV disease is associated with an increased risk of cardiac complications in kidney transplant recipients. In our series, angiographic vessel occlusion was more common in recipients with CMV disease. This interesting finding may support the theory that CMV plays some role in the pathogenesis of CHD.

Clinical determinants of multiple acute rejection episodes in kidney transplant recipients

BACKGROUND

Recipients with multiple (more than one) acute rejection (AR) episodes have significantly lower graft survival rates than those with no AR or only one treated episode. However, fewer than 50% of recipients treated for one AR episode will have another episode.

METHODS

We studied recipients with at least one AR episode to determine whether any clinical features could identify risk factors for multiple AR.

RESULTS

Between January 1, 1984, and June 30, 1997, a total of 1793 recipients underwent a kidney transplant at our institution. Of these, 354 were treated for one AR episode, 307 for more than one. By multivariate analysis, recipients at highest risk for multiple AR episodes were those with initial delayed or slow graft function (relative risk=1.5, P=0.05), those with initially severe AR (as judged by vascular involvement or steroid resistance), and those with an initial early AR episode (<6 months posttransplant). The remaining variables tested were not significant. Graft survival in recipients with more than one AR episode was significantly lower than in those with only one AR episode. Graft survival at 5 years posttransplant was 52.5% in recipients with more than one AR episode and 85.1% in recipients with one AR episode (P=0.0001). Chronic rejection as a cause of graft loss was significantly more common in recipients with more than one vs. only one AR episode (34.8% vs. 8.9%, P=0.001).

CONCLUSION

Clinical features may be used to identify recipients at higher risk for multiple AR episodes. These recipients can then be targeted with more aggressive or novel immunosuppressive regimens in an attempt to reduce the likelihood of another AR episode.

Renal transplantation for type II diabetic patients compared with type I diabetic patients and patients over 50 years old: a single-center experience

INTRODUCTION

Transplantation of renal allografts for Type II diabetic patients has become increasingly common. Like Type I diabetics and patients over age 50, Type II diabetics are in a high-risk category for renal transplantation. Some investigators argue that the scarce resources of the valuable donor pool should not be allocated to these high-risk, older individuals with end-stage renal disease (ESRD) who often have significant comorbidity. We studied the outcome of renal transplantation for 90 Type II diabetics and compared it with the outcome for Type I diabetics and patients over age 50 with other primary diseases.

METHODS

We conducted a retrospective review of data on all renal transplants performed at the University of Minnesota since September 1984 for Type II diabetics. We analyzed both patient and graft survival rates and compared them with the outcome for Type I diabetics and separately for all nondiabetics over age 50. We grouped recipients by donor source (living vs. cadaver) and age at transplant (< 50 vs. > 50). We studied reasons for graft loss, patient death, pre-operative morbidity, and post-operative complications.

RESULTS

We found that recipient age and donor source did not affect outcome. Overall 5-yr patient survival for Type II diabetics was 61%; graft survival, 53%. Type II diabetics had significantly worse patient and graft survival than Type I diabetics and than nondiabetics over age 50. However, death-censored graft survival was not different between these groups, suggesting little difference in immunologic graft loss.

CONCLUSIONS

Renal transplantation is a relatively safe, viable option for Type II diabetics with ESRD and significant comorbidity. Although their overall graft survival is less than for Type I diabetics and for nondiabetics over age 50, the immunologic graft failure rate is the same in all three groups.

Living unrelated donors in kidney transplants: better long-term results than with non-HLA-identical living related donors?

BACKGROUND

Given the severe organ shortage and the documented superior results obtained with living (vs. cadaver) donor kidney transplants, we have adopted a very aggressive policy for the use of living donors. Currently, we make thorough attempts to locate a living related donor (LRD) or a living unrelated donor (LURD) before proceeding with a cadaver transplant.

METHODS

We compared the results of our LURD versus LRD transplants to determine any significant difference in outcome.

RESULTS

Between 1/1/84 and 6/30/98, we performed 711 adult kidney transplants with non-HLA-identical living donors. Of these, 595 procedures used LRDs and 116 used LURDs. Immunosuppression for both groups was cyclosporine-based, although LURD recipients received 5-7 days of induction therapy (antilymphocyte globulin or antithymocyte globulin), whereas LRD recipients did not. LURD recipients tended to be older, to have inferior HLA matching, and to have older donors than did the LRD recipients (all factors potentially associated with decreased graft survival). Short-term results, including initial graft function and incidence of acute rejection, were similar in the two groups. LURD recipients had a slightly higher incidence of cytomegalovirus disease (P=NS). We found no difference in patient and graft survival rates. However, the incidence of biopsy-proven chronic rejection was significantly lower among LURD recipients (16.7% for LRD recipients and 10.0% for LURD recipients at 5 years posttransplant; P=0.05). LRD recipients also had a greater incidence of late (>6 months posttransplant) acute rejection episodes than did the LURD recipients (8.6% vs. 2.6%, P=0.04). The exact reason for these findings is unknown.

CONCLUSION

Although LURD recipients have poorer HLA matching and older donors, their patient and graft survival rates are equivalent to those of non-HLA-identical LRD recipients. The incidence of biopsy-proven chronic rejection is lower in LURD transplants. Given this finding and the superior results of living donor (vs. cadaver) transplants, a thorough search should be made for a living donor-LRD or LURD-before proceeding with a cadaver transplant.

Predicting clinical outcome in the elderly renal transplant recipient

BACKGROUND

The purpose of this study was to evaluate graft and patient survival in first-time kidney transplant recipients 60 years old or older, and to identify pretransplant risk factors that predict clinical outcome.

METHODS

We reviewed the clinical course of 206 recipients, 60 years old or older, of first kidney transplants at the University of Minnesota. Patient and graft survival were compared with 1640 patients aged 18 to 59 transplanted during the same time period. Regression analysis was performed to identify risk factors that predicted a poor outcome.

RESULTS

In patients 60 years old or older, graft survival at one and five years was 86 and 60%, and patient survival at one and five years was 90 and 68%, respectively. Graft and patient survival were decreased compared with recipients aged 18 to 59, but were similar when censored for patient death as a cause of graft loss. A pretransplant history of nonskin malignancy and vascular disease and a current smoking history were risk factors for decreased graft and patient survival. To determine the potential impact of screening for low-risk patients, we evaluated graft and patient survival in patients age > or =60 without these risk factors versus those with one or more risk factors. In the absence of risk factors, both graft and patient survival were significantly improved compared with patients with these risk factors and were equivalent to that of patients aged 18 to 59.

CONCLUSIONS

Renal transplantation is a safe and effective therapy for the older renal failure patient. In the absence of identified risk factors, graft survival is equivalent to that seen in younger patients.

Impact of acute rejection on development of chronic rejection in pediatric renal transplant recipients

For pediatric kidney transplant recipients, chronic rejection has become the predominant cause of graft loss. This article reviews risk factors for chronic rejection and what can be done to lower the risk of chronic rejection for future transplant recipients.

Iliac artery stenosis masquerading as diuretic resistant congestive heart failure

Iliac artery stenosis is a rare cause of renal dysfunction in renal allograft recipients. Its presence can mimic renovascular hypertension and yet alter the very radiologic tests used to diagnose renal artery stenosis. We investigate a case of iliac artery stenosis that presented with diuretic resistant fluid overload, hypertension and limb claudication that exposed the pitfalls in the diagnosis and management of this condition. Successful stent placement, 8 months after transplant, resulted in return of the serum creatinine below the post-transplant nadir.

Should I accept this kidney?

BACKGROUND

Transplant candidates frequently ask whether they should, based on information available at the time, accept a cadaver kidney or wait for a potentially better one.

METHODS

We analyzed 937 first and second cadaver transplants done between January 1, 1984 and December 31, 1997 to determine if information available at the time an offer is made could be used to predict long-term graft survival.

RESULTS

By Cox regression, risk factors for worse long-term graft survival were older donor age, cardiovascular or cerebrovascular cause of donor death, and delayed graft function (DGF). HLA-ABDR mismatch was marginally significant. Whether DGF will occur is not known at the time of an offer, but risk factors can be determined; we found these to be older donor age and > 10% panel-reactive antibodies (PRA) at transplantation (by Cox regression). Using these variables (PRA, ABDR mismatch, donor age, and donor cause of death) known at the time of an offer, we calculated the relative risk of worse long-term graft survival for each subgroup (Table 3 in manuscript). In general, older age and donor death from cardiovascular or cerebrovascular disease were associated with worse outcome. Kidneys from donors of < 50 yr had the best outcome, irrespective of match.

CONCLUSION

The data provided can be used to help guide patients as to whether they are better off accepting an offered kidney or waiting for a potentially better one. If an offer is declined, the next kidney may have a potentially worse outcome.