Improvement in conjunctival microangiopathy after simultaneous pancreas-kidney transplants

Functional slit lamp biomicroscopy metrics correlate with cardiovascular risk

PURPOSE

Our aim was to correlate cardiovascular risk factor estimation with bulbar conjunctival blood flow metrics as measured through Functional Slit Lamp Biomicroscopy (FSLB).

METHODS

Cross-sectional study of individuals with otherwise healthy eyelid and corneal anatomy recruited from the Miami Veterans Affairs (VA) Healthcare System eye clinic. We measured conjunctival microvascular hemodynamics by mounting a camera on a slit lamp and cardiovascular risk using the Framingham risk score. Our main outcome measures were correlations between conjunctival vessel parameters (axial and cross-sectional blood flow velocity, blood flow rate) and Framingham score.

RESULTS

We included 84 patients who underwent FSLB. The mean age was 60 years, the majority were male (88%) and approximately half the patients were black (54%). Mean vessel diameter was similar between all Framingham score categories. Axial and cross-sectional blood flow velocities and blood flow rate were lower in individuals with higher Framingham risk score. Specifically, mean cross-sectional blood flow velocity in individuals with a low Framingham risk score was 0.37 ± 0.0.9 mm/s, with an intermediate score was 0.30 ± 0.09 mm/s, and with a high score was 0.29 ± 0.10 mm/s, p = 0.04. Mean blood flow rate in individuals with a low Framingham risk score was 133.4 ± 59.6 pl/s, with an intermediate score was 123.6 ± 39.3 pl/s, and with a high score was 121.9 ± 52.6 pl/s, p = 0.04. The beta coefficient of the blood flow rate for change in Framingham score was -0.73; 95% CI-1.34-0.13, p = 0.02, adjusted for race.

CONCLUSION

FSLB correlates with cardiovascular risk estimation. Future studies should evaluate if FSLB can predict cardiovascular outcomes.

Assesment of Conjunctival Microangiopathy in a Patient with Diabetes Mellitus Using the Retinal Function Imager

Diabetes mellitus (DM) is notorious for causing retinal microangiopathy, but bulbar conjunctival microangiopathy (CM) mirroring the established retinal vessel changes, has also been observed. Recent studies suggest that CM occurs in all DM patients in various degrees depending on disease severity and occur even before non-proliferative retinopathy develops. Thus, CM might provide a means of early detection or even form a basis for early intervention of disease progression in DM patients. Herein we present - to our knowledge for the first time-the feasibility and applicability in diagnostic imaging of CM in a diabetic patient using a commercially available Retinal Function Imager (RFI, Optical Imaging Ltd, Rehovot, Israel).

Human conjunctival microvasculature assessed with a retinal function imager (RFI)

The conjunctival and cerebral vasculatures share similar embryological origins, with similar structural and physiological characteristics. Tracking the conjunctival microvasculature may provide useful information for predicting the onset, progression and prognosis of both systemic and central nervous system (CNS) vascular diseases. The bulbar conjunctival vasculature was imaged using a retinal function imager (RFI, Optical Imaging Ltd, Rehovot, Israel). Hemoglobin in red blood cells was used as an intrinsic motion-contrast agent in the generation of detailed noninvasive capillary-perfusion maps (nCPMs) and the calculation of the blood flow velocity. Five healthy subjects were imaged under normal conditions and again under the stress condition of wearing a contact lens. The retina was also imaged in one eye of one subject for comparison. The nCPMs showed the conjunctival microvasculature in exquisite detail, which appeared as clear as the retinal nCPMs. The blood flow velocities in the temporal conjunctival microvasculature were 0.86±0.08 (mean±SD, mm/s) for the bare eye and 0.99±0.11 mm/s with contact lens wear. It is feasible to use RFI for imaging the conjunctival vasculature.

Simultaneous pancreas-kidney transplantation reduces excess mortality in type 1 diabetic patients with end-stage renal disease

BACKGROUND

Diabetic renal disease continues to be the most significant cause of end-stage renal disease (ESRD) in the United States. Renal transplantation improves diabetic ESRD patient survival; however, the diabetic state remains associated with poor patient survival. Simultaneous pancreas-kidney (SPK) transplantation can restore normoglycemia and thus may improve outcomes.

METHODS

We assessed the impact of SPK on age-range-matched type 1 diabetic patients who underwent renal transplantation at a single center. The observed/expected life span and annual mortality rates (AMRs) were used as measures of survival. A Cox proportional hazards analysis was used to analyze the impact of potential variables on mortality in SPK recipients.

RESULTS

SPK transplantation (N = 335) increased the observed/expected life span compared with diabetic cadaveric (DM-Cad, N = 147) and live-donor (DM-Live, N = 160) transplant recipients (P = 0.004) and significantly reduced the AMRs (SPK, 1. 5%; DM-Cad, 6.27%; DM-Live, 3.65%, P = 0.008, SPK vs. other DM). Moreover, the SPK observed/expected life span and AMR were not significantly different from that of age-range-matched nondiabetic transplant recipients (N = 492). The only variable that was significantly associated with patient survival was discharge serum creatinine (relative risk 1.16, P < or = 0.0154).

CONCLUSION

These data demonstrate that SPK improves the ability for type 1 diabetic patients to live more of their expected life span. This suggests that glycemic control, even as a late intervention in a diabetic patient's lifetime, may beneficially affect survival.

The impact of hypoalbuminemia in kidney-pancreas transplant recipients

BACKGROUND

Hypoalbuminemia is associated with poorer outcomes in renal transplantation. Diabetes can compound hypoalbuminemia's detrimental effects. Kidney-pancreas transplantation alters the diabetic milieu; yet, some patients continue to be hypoalbuminemic.

METHODS

We retrospectively analyzed 232 patients who underwent simultaneous kidney-pancreas transplantation (SPK) between 1993 and 1997 to determine the incidence and clinical correlates of hypoalbuminemia in SPK recipients. Post-SPK hypoalbuminemia was defined as a serum albumin level < or =3.5 g/dl. Univariate analyses were performed to determine whether post-SPK hypoalbuminemia was associated with pre-SPK variables. The effect of albumin level and hypoalbuminemia on the risk of post-SPK events (cardiac events, cytomegalovirus [CMV] infection, rejection, readmission, kidney and pancreas graft failure, and death) was examined with a Cox proportional hazards model.

RESULTS

The study population consisted of 149 men and 83 women. Average follow-up was 2.0+/-1.3 years. Hypoalbuminemia (serum albumin level < or =3.5 g/dL) was most common early after SPK (3 months: 44% of evaluable patients were hypoalbuminemic; 12 months: 15.3%; 36 months: 8.3%). Acute rejection episodes and readmission were the most common adverse events after SPK transplantation. There were 24 episodes of renal allograft loss and only 5 cardiac events. Ten SPK recipients died during the study time period. SPK-related hypoalbuminemia was associated with an increased risk for CMV infection (risk ratio [RR] 2.5; P<0.02), renal graft failure (RR 2.41; P=0.05), pancreas graft failure (RR 3.66; P=0.01), and a trend toward an increased risk for death (RR 2.8; P=0.19).

CONCLUSIONS

Post-SPK hypoalbuminemia resolves over time in many patients. Persistent post-SPK hypoalbuminemia is associated with an increased risk for CMV infection, graft loss, and a trend toward decreased survival. Efforts to improve nutrition, as it may affect hypoalbuminemia in SPK recipients, may be one strategy for improving SPK outcomes.

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.