Mean Arterial Blood Pressure While Awaiting Kidney Transplantation Is Associated With the Risk of Primary Nonfunction

Kidney Transplantation Outcomes of Patients With Chronic Hypotension in Dialysis

Introduction

Persistent chronic hypotension affects 5-10% of dialysis patients. It seems to be reversible after receiving a functioning graft, but data regarding its influence on transplant outcomes are scarce. We analyze the evolution of patients with chronic hypotension in dialysis who undergo kidney transplantation at our center.

Methods

A retrospective observational study was conducted. Sixty-six patients with chronic hypotension (defined as systolic blood pressure ≤ 100 mm Hg at the time of transplantation) were identified. A control group of 66 non-hypotensive patients was assigned. The evolution of both groups was compared.

Results

Hypotensive patients had higher rates of primary non-function (18.2% vs. 6.1%; P = 0.03) mainly due to venous thrombosis of the allograft, worse renal function at the end of follow-up (eGFR of 35 mL/min/1.73 m2 vs 48 mL/min/1.73 m2, P = 0.001) but there was no statistical difference in graft survival after censoring for primary non-function. After multivariable adjustment, chronic hypotension remained an independent predictor factor for graft failure (adjusted HR of 2.85; 95% CI: 1.24-6.57; P = 0.014). Use of vasoactive drugs and anticoagulation in hypotensive patients was associated with 7.1% of venous graft thrombosis compared to 17.3% in those with no intervention (P = 0.68). Receiving a functioning graft implied blood pressure normalization in patients with chronic hypotension.

Conclusion

Chronic hypotension in dialysis has a negative impact on short-term kidney transplant outcomes but a lower impact on long-term results. It is reversible after receiving a functioning graft. Identifying this subgroup of patients seems crucial to implement measures aimed at improving transplant results.

Recipient pre-existing chronic hypotension is associated with delayed graft function and inferior graft survival in kidney transplantation from elderly donors

BACKGROUND

Pre-existing chronic hypotension affects a percentage of kidney transplanted patients (KTs). Although a relationship with delayed graft function (DGF) has been hypothesized, available data are still scarce and inconclusive.

METHODS

A monocentric retrospective observational study was performed on 1127 consecutive KTs from brain death donors over 11 years (2003-2013), classified according to their pre-transplant Mean Blood Pressure (MBP) as hypotensive (MBP < 80 mmHg) or normal-hypertensive (MBP ≥ 80 mmHg, with or without effective antihypertensive therapy).

RESULTS

Univariate analysis showed that a pre-existing hypotension is associated to DGF occurrence (p<0.01; OR for KTs with MBP < 80 mmHg, 4.5; 95% confidence interval [CI], 2.7 to 7.5). Chronic hypotension remained a major predictive factor for DGF development in the logistic regression model adjusted for all DGF determinants. Adjunctive evaluations on paired grafts performed in two different recipients (one hypotensive and the other one normal-hypertensive) confirmed this assumption. Although graft survival was only associated with DGF but not with chronic hypotension in the overall population, stratification according to donor age revealed that death-censored graft survival was significantly lower in hypotensive patients who received a KT from >50 years old donor.

CONCLUSIONS

Our findings suggest that pre-existing recipient hypotension, and the subsequent hypotension-related DGF, could be considered a significant detrimental factor, especially when elderly donors are involved in the transplant procedure.

Kidney transplantation in patients with severe preoperative hypertension

BACKGROUND

Severe systemic hypertension (HTN) is a risk factor for perioperative cardiovascular complications; however, its impact at the time of kidney transplantation (KTX) is not well defined.

METHODS

A retrospective cohort study of adult kidney-only transplant recipients between October 2009 and December 2012 was performed to examine outcomes between patients with (n = 111) and without (n = 98) severe preoperative HTN defined as SBP > 180 or DBP > 110 mmHg.

RESULTS

Recipients with severe HTN were older (56.7 ± 13.0 vs. 53.5 ± 12.4 yr, p = 0.07) and significantly more likely to receive an expanded criteria donor kidney (32.7% vs. 12.2%, p = 0.02). No patients developed hypertensive crisis, intracranial hemorrhage, or life threatening ventricular arrhythmias within 30 d post-transplantation; however, three patients with severe HTN had cardiac events: two with demand ischemia and one with decompensate heart failure. Two patients in the control group had decompensated heart failure. There were no differences between the groups in terms of cardiac event (2.7% vs. 2.0%, p = 0.75), one-yr patient survival (98.2% vs. 98.0%, p = 0.90) or graft survival (90.1% vs. 92.9%, p = 0.48), nadir creatinine > 2 mg/dL (4.6% vs. 6.2%, p = 0.62), length of stay > 6 d (37.8% vs. 35.7%, p = 0.75), and DGF (52.3% vs. 63.3%, p = 0.11).

CONCLUSIONS

Our results suggest that severe preoperative HTN should not be considered an absolute contraindication to kidney transplant in patients who are otherwise clinically stable.

Primary graft dysfunction after liver transplantation

BACKGROUND

Primary graft dysfunction (PGD) causes complications in liver transplantation, which result in poor prognosis. Recipients who develop PGD usually experience a longer intensive care unit and hospital stay and have higher mortality and graft loss rates compared with those without graft dysfunction. However, because of the lack of universally accepted definition, early diagnosis of graft dysfunction is difficult. Additionally, numerous factors affect the allograft function after transplantation, making the prediction of PGD more difficult. The present review was to analyze the literature available on PGD and to propose a definition.

DATA SOURCE

A search of PubMed (up to the end of 2012) for English-language articles relevant to PGD was performed to clarify the characteristics, risk factors, and possible treatments or interventions for PGD.

RESULTS

There is no pathological diagnostic standard; many documented definitions of PGD are different. Many factors, such as donor status, procurement and transplant process and recipient illness may affect the function of graft, and ischemia-reperfusion injury is considered the direct cause. Potential managements which are helpful to improve graft function were investigated. Some of them are promising.

CONCLUSIONS

Our analyses suggested that the definition of PGD should include one or more of the following variables: (1) bilirubin ≥ 10 mg/dL on postoperative day 7; (2) international normalized ratio ≥ 1.6 on postoperative day 7; and (3) alanine aminotransferase or aspartate aminotransferase >2000 IU/L within 7 postoperative days. Reducing risk factors may decrease the incidence of PGD. A majority of the recipients could recover from PGD; however, when the graft progresses into primary non-function, the patients need to be treated with re-transplantation.

Efficacy and safety of phenylephrine in the management of low systolic blood pressure after renal transplantation

BACKGROUND

Phenylephrine can be used to treat postoperative hypotension after renal transplantation. However, its effect on the renal allograft is unknown. We evaluated the safety and efficacy of this approach.

STUDY DESIGN

A retrospective cohort study of 307 renal transplant recipients between November 2005 and October 2011 was conducted, including 75 who required phenylephrine, 46 of whom were deceased donors renal transplant (DDRT) recipients and 29 who were living donor transplant (LDRT) recipients. These were compared with 75 controls matched by sex, age, type of transplant, and etiology of renal failure. The primary outcome was rate of delayed graft function (DGF). The following statistical tools were used: paired t-test for continuous data, McNemar's test for categorical data, and a nonlinear mixed decay model for change in serum creatinine (Cr).

RESULTS

Of 46 DDRT recipients who required phenylephrine, 17 developed DGF compared with 10 matched controls (relative risk [RR] 2.9, CI 1.4 to 6.0, p = 0.0040). Only one LDRT recipient required hemodialysis (DGF). No differences were noted in the number of hemodialysis treatments required (mean 2.7 in treatment group vs 3.4 in control). No significant differences were observed between phenylephrine and control groups in renal function on postoperative days 30, 90, and 365 Cr or graft survival. The immediate postoperative normalization of Cr was slower in the DDRT phenylephrine group compared with DDRT controls (p < 0.0001), but no difference in Cr was noted before discharge (p = 0.49).

CONCLUSIONS

Although there is a brief association between phenylephrine administration and a slower rate of transplanted kidney recovery, there is no clinically or statistically significant impaired outcome in the phenylephrine group at time of discharge. Administration of phenylephrine to support low blood pressure after renal transplant appears safe.