The effect of haemodialysis on transcutaneous oxygen tension in patients with diabetes—a pilot study

Variability of toe pressures during haemodialysis: comparison of people with and without diabetes; a pilot study

BACKGROUND

Diabetes, end stage renal disease (ESRD), and peripheral arterial disease (PAD) are associated with a higher risk of diabetes-related lower limb amputation. Timely identification of PAD with toe systolic blood pressure (TSBP) and toe-brachial pressure index (TBPI) is critical in order to implement foot protection strategies to prevent foot complications in people with ESRD. There is limited evidence describing the effect of haemodialysis on TSBP and TBPI. This study aimed to determine the variability of TSBP and TBPI during haemodialysis in people with ESRD, and to determine whether any observed variability differed between people with and without diabetes.

METHODS

TSBP and TBPI were taken before dialysis (T1), one hour into dialysis (T2) and in the last 15 min of dialysis (T3) during a single dialysis session. Linear mixed effects models were undertaken to determine the variability in TSBP and TBPI across the three time points and to determine whether this variability differed between people with and without diabetes.

RESULTS

Thirty participants were recruited, including 17 (57%) with diabetes and 13 (43%) with no diabetes. A significant overall reduction in TSBP was observed across all participants (P < 0.001). There was a significant reduction in TSBP between T1 and T2 (P < 0.001) and between T1 and T3 (P < 0.001). There was no significant overall change in TBPI over time (P = 0.62). There was no significant overall difference in TSBP between people with diabetes and people with no diabetes (mean difference [95% CI]: -9.28 [-40.20, 21.64], P = 0.54). There was no significant overall difference in TBPI between people with diabetes and people with no diabetes (mean difference [95% CI]: -0.01 [-0.17, 03.16], P = 0.91).

CONCLUSION

TSBP and TBPI are an essential part of vascular assessment of the lower limb. TBPI remained stable and TSBP significantly reduced during dialysis. Given the frequency and duration of dialysis, clinicians taking toe pressures to screen for PAD should be aware of this reduction and consider how this may have an impact on wound healing capacity and the development of foot related complications.

Correlation of ACR and TcPO2 in diabetic kidney disease patients: A pilot study

OBJECTIVE

Transcutaneous oxygen pressure (TcPO2) is used to assess microcirculation clinically; however, it is not widely available especially in rural hospital. The study was designed to explore potential alternatively biomarkers to assess microcirculation in diabetic kidney disease (DKD).

METHODS

A total of 404 patients from Xuzhou first hospital were recruited according to the case records system. Patients were grouped via the ratio of albuminuria and creatinine (ACR; <30 mg/g, 30-300 mg/g, >300 mg/g). Biomarkers in different ACR groups were compared by analysis of variance. Correlation analysis was determined by Pearson or Spearman analysis and binary logistic regression. The receiver operating characteristics (ROC) curve was performed to elucidate the prediction effect of ACR on TcPO2.

RESULTS

A total of 404 diabetic patients were recruited with 248 patients diagnosed as DKD and 156 non-DKDs. Age and cystatin C were significantly higher in the ACR3 group compared with those in the ACR1 group, whereas glomerular filtration rate, low-density lipoprotein cholesterol, and TcPO2 were markedly decreased in the ACR3 group (p < .05). Frequency of low TcPO2 (<40 mm Hg) was markedly increased as increment of ACR stages with 30.2% in the ACR3 group (p < .01). There was a negative correlation between TcPO2 and age, ACR, chronic kidney disease (CKD), fast blood glucose, diabetes mellitus (DM) duration, and diabetic neuropathy. Further, binary logistic regression showed ACR was an independent influence factor for low TcPO2. After adjusting for age, gender, hypertension, DM duration, body mass index, glycated hemoglobin, diabetic neuropathy, and CKD, ACR was still an independent influence factor for TcPO2 (odds ratio = 2.464, p < .01). The area under the ROC curve was 0.768 (95% confidence interval: 0.700-0.836, p < .001) for ACR. The analysis of ROC curves revealed a best cutoff for ACR was 75.25 mg/g and yielded a sensitivity of 71.7% and a specificity of 71.7%.

CONCLUSIONS

ACR could be used as an alternative biomarker for assessing microcirculation in DKD patients.

Intradialytic Hypotension and Newly Recognized Peripheral Artery Disease in Patients Receiving Hemodialysis

RATIONALE & OBJECTIVE

Intradialytic hypotension (IDH) may decrease systemic circulation to the legs, exacerbating symptoms of peripheral artery disease (PAD). We sought to evaluate the relationship between IDH and newly recognized lower extremity PAD among hemodialysis patients.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Linking data from the US Renal Data System to the electronic health records of a large dialysis provider, we identified adult patients (≥18 years of age) with Medicare Parts A and B who initiated dialysis (2006-2011) without previously recognized PAD.

EXPOSURE

The time-varying proportion of hemodialysis sessions with IDH defined as the nadir intradialytic systolic blood pressure <90 mm Hg. We categorized the proportion of sessions with IDH within serial 30-day intervals as 0%, >0% to <15%, 15% to <30%, and ≥30%.

OUTCOMES

Newly recognized PAD was ascertained using PAD diagnostic and procedure codes for amputation or revascularization, in serial 30-day intervals subsequent to each 30-day exposure interval.

ANALYTICAL APPROACH

To account for the competing risks of death and kidney transplantation, we estimated unadjusted and adjusted subdistribution hazard ratios using the Kaplan-Meier multiple imputation method in combination with the extended Cox model to account for IDH as a time-varying exposure.

RESULTS

Among 45,591 patients, those with more frequent baseline IDH had a higher prevalence of cardiovascular diseases. During 61,725 person-years of follow-up, 7,886 patients had newly recognized PAD. We found a graded, direct association between IDH and newly recognized PAD. For example, having IDH in ≥30% of dialysis sessions during a given 30-day interval (vs 0%) was associated with a 24% (95% CI, 17%-32%) higher hazard than having newly recognized PAD in the subsequent 30 days.

LIMITATIONS

Unmeasured confounding; ascertainment of PAD from claims.

CONCLUSIONS

Patients receiving hemodialysis who had more frequent IDH had higher rates of newly recognized PAD. Patients with frequent IDH may warrant careful examination for PAD.

Risk factors for foot ulceration in adults with end-stage renal disease on dialysis: a prospective observational cohort study

Background

Dialysis patients experience high rates of foot ulceration. Although risk factors for ulceration have been extensively studied in patients with diabetes, there is limited high-quality, longitudinal evidence in the dialysis population. Therefore, this study investigated risk factors for foot ulceration in a stable dialysis cohort.

Methods

We prospectively collected clinical, demographic, health status, and foot examination information on 450 adults with end-stage renal disease from satellite and home-therapy dialysis units in Melbourne, Australia over 12 months. The primary outcome was foot ulceration. Cox proportional hazard modelling and multinomial regression were used to investigate risk factors.

Results

Among 450 dialysis patients (mean age, 67.5 years; 64.7% male; 94% hemodialysis; 50.2% diabetes), new cases of foot ulceration were identified in 81 (18%) participants. Overall, risk factors for foot ulceration were neuropathy (HR 3.02; 95% CI 1.48 to 6.15) and previous ulceration (HR 2.86; CI 1.53 to 5.34). In those without history of ulceration, nail pathology (RR 3.85; CI 1.08 to 13.75) and neuropathy (RR 2.66; CI 1.04 to 6.82) were risk factors. In those with history of ulceration, neuropathy (RR 11.23; CI 3.16 to 39.87), peripheral arterial disease (RR 7.15; CI 2.24 to 22.82) and cerebrovascular disease (RR 2.08; CI 1.04 to 4.16) were risk factors. There were 12 (2.7%) new amputations, 96 (21.3%) infections, 24 (5.3%) revascularizations, 42 (9.3%) foot-related hospitalizations, and 52 (11.6%) deaths.

Conclusions

Neuropathy and previous ulceration are major risk factors for foot ulceration in dialysis patients. Risk factors differ between those with and without prior ulceration. The risk factors identified will help to reduce the incidence of ulceration and its associated complications.

Excess risk of lower extremity amputations in people with type 1 diabetes compared with the general population: amputations and type 1 diabetes

OBJECTIVE

This study investigates how the excess risk of lower extremity amputations (amputations) in people with type 1 diabetes mellitus (DM) differs from the general population by diabetes duration, glycemic control, and renal complications.

RESEARCH DESIGN AND METHODS

We analyzed data from people with type 1 DM from the Swedish National Diabetes Register without prior amputation from January 1998 to December 2013. Each person (n=36 872) was randomly matched with five controls by sex, age, and county (n=184 360) from the population without diabetes. All were followed until first amputation, death or end of follow-up.

RESULTS

The overall adjusted HR for all amputation was 40.1 (95% CI 32.8 to 49.1) for type 1 DM versus controls. HR increased with longer diabetes duration. The incidence of amputation/1000 patient-years was 3.18 (95% CI 2.99 to 3.38) for type 1 DM and 0.07 (95% CI 0.05 to 0.08) for controls. The incidence decreased from 1998-2001 (3.09, 95% CI 2.56 to 3.62) to 2011-2013 (2.64, 95% CI 2.31 to 2.98). The HR for major amputations was lower than for minor amputations and decreased over the time period (p=0.0045). Worsening in glycemic control among patients with diabetes led to increased risk for amputation with an HR of 1.80 (95% CI 1.72 to 1.88) per 10 mmol/mol (1%) increase in hemoglobin A1c.

CONCLUSIONS

Although the absolute risk of amputation is relatively low, the overall excess risk was 40 times that of controls. Excess risk was substantially lower for those with good glycemic control and without renal complications, but excess risk still existed and is greatest for minor amputations.

Periprocedural Concerns in the Patient with Renal Disease

Treating patients with kidney disease can be both a difficult and a complex process. Understanding how to care for patients who have kidney disease is essential for lowering perioperative as well as periprocedural morbidity and mortality. The primary aim in renal evaluation and care is to control and mitigate factors that may result in acute kidney injury (AKI) and/or cause further decline in renal function. It is essential for the foot and ankle specialist to recognize patients who are predisposed to developing or already have impairment of renal function.

What lies downstream: Cellular oxygen delivery during hemodialysis

Hemodialysis has been linked to structural and functional damage to vital organs such as the brain and heart, possibly via repetitive intradialytic organ ischemia. There is increasing recognition that tissue ischemia can occur without changes in standard hemodynamic parameters such as blood pressure, leading to interest in more direct assessment of the adequacy of oxygen delivery to tissues. In this article, we discuss our current understanding of what happens to cellular oxygen delivery during hemodialysis: we review the underlying physiology, potential measurement techniques, and the clinical literature to date.

Does the Start of Dialysis Initiate a Period of Increased Risk of Ulceration or Amputation?

BACKGROUND

Dialysis therapy is associated with an increased incidence of lower-extremity wounds and amputations. We compared the incidence of foot ulcers and amputations before and after the start of dialysis.

METHODS

We evaluated 150 consecutive diabetic patients receiving dialysis and compared the incidence of foot complications 30 months before and after initiation of hemodialysis. We used claims data for diabetes, ulceration, and dialysis and abstracted medical records to verify diagnoses and dates of ulcers and amputations. We compared initial and cumulative ulcer/amputation incidence to account for multiple events in the same person over time. We used the same formula to determine the incidence rate difference and 95% confidence intervals (CIs) to compare new ulcers and amputations during the study.

RESULTS

There was no significant difference in the incidence of first foot ulcers before (91.7 per 1,000 patient-years; 95% CI, 73.7-112.3 per 1,000 patient-years) and after (82.7; 95% CI, 65.7-102.3) the start of hemodialysis. The incidence of cumulative ulcers was significantly higher before (304.0 per 1,000 patient-years; 95% CI, 270.8-340.2) compared with after (210.7 per 1,000 patient-years; 95% CI, 183.0-240.9) dialysis. There was no difference in the incidence of first amputation before (29.3 per 1,000 patient-years; 95% CI, 1 9.4-41.7 per 1,000 patient-years) and after (37.3 per 1,000 patient-years; 95% CI, 19.4-41.7 per 1,000 patient-years) dialysis or in the cumulative incidence of amputations before (61.3 per 1,000 patient-years; 95% CI, 46.7-8.4 per 1,000 patient-years) and after (58.7 per 1,000 patient-years; 95% CI, 44.5-75.5 per 1,000 patient-years) dialysis.

CONCLUSIONS

There was no increase in the incidence of ulcers or amputations after beginning hemodialysis.

Factors associated with foot ulceration and amputation in adults on dialysis: a cross-sectional observational study

BACKGROUND

Adults on dialysis are at increased risk of foot ulceration, which commonly precedes more serious lower limb complications, including amputation. Limited data exist regarding the prevalence and factors associated with foot disease in this population. Hence, this study set out to investigate factors associated with foot ulceration and amputation in a dialysis cohort.

METHODS

This study presents a cross-sectional analysis of baseline data from a multi-center prospective cohort study. We recruited 450 adults with end-stage renal disease on dialysis from multiple satellite and home-therapy dialysis units in Melbourne, Australia from January to December 2014. Data collection consisted of a participant interview, medical record review, health-status questionnaire and non-invasive foot examination. Logistic regression analyses were conducted to evaluate associations between screened variables and study outcomes.

RESULTS

Mean age was 67.5 (SD, 13.2) years, 64.7% were male, 94% were on hemodialysis, median dialysis duration was 36.9 (IQR, 16.6 to 70.1) months, and 50.2% had diabetes. There was a high prevalence of previous ulceration (21.6%) and amputation (10.2%), 10% had current foot ulceration, and 50% had neuropathy and/or peripheral arterial disease. Factors associated with foot ulceration were previous amputation (OR, 10.19), peripheral arterial disease (OR, 6.16) and serum albumin (OR, 0.87); whereas previous and/or current ulceration (OR, 167.24 and 7.49, respectively) and foot deformity (OR, 15.28) were associated with amputation.

CONCLUSIONS

Dialysis patients have a high burden of lower limb complications. There are markedly higher risks of foot ulceration and/or amputation in those with previous and/or current ulceration, previous amputation, peripheral arterial disease, lower serum albumin, and foot deformity. Although not a major risk factor, diabetes in men was an important effect modifier for risk of ulceration.

Predictors of first ischemic lower limb ulcer in dialysis patients: an observational cohort study

BACKGROUND

Lower limb ischemia affects the quality of life, physical activity and life expectancy of dialysis patients. The aim of this study was to investigate the risk factors associated with ischemic foot ulcers considering clinical, laboratory and therapeutic domains.

METHODS

This observational cohort study was based on data from the Nephrology and Dialysis Department database of Alessandro Manzoni Hospital, Lecco (Italy). All of the incident patients who started dialysis between 1 January 1999 and 29 February 2012 were enrolled, excluding temporary guests, patients with acute renal failure and patients with previous limb ischemia or amputation. Multivariate Cox regression analysis identified the predictors in each domain, which were matched in the final model. A time-dependent approach was used to take into account the evolution of some of the prognostic covariates.

RESULTS

Of the 526 incident dialysis patients, 120 developed a lower limb ischemic lesion after a median of 13 months. The incidence of new ulcers was constant during the study period (6 per 100 person-years), but higher in the diabetics with a relative rate of 4.5. The variables significantly related to an increased risk of lower limb ulcers were age, male gender, diabetes, ischemic heart disease, treatment with proton pump inhibitors, iron, anticoagulants and calcium-based binders, and blood levels of phosphorus, triglycerides and C-reactive protein.

CONCLUSION

The incidence of lower limb ulcers was highest during the early dialysis follow-up and was associated with, in addition to diabetes, modifiable laboratory and therapeutic predictors such as anticoagulants, proton pump inhibitors, calcium-containing binders, calcimimetics and iron.

Association between estimated glomerular filtration rate and outcomes in patients with diabetic foot ulcers: a 3-year follow-up study

OBJECTIVE

End-stage renal disease and dialysis have been proven to be associated with poor prognoses in diabetic foot ulcers (DFUs). However, it has rarely been reported whether and to what extent milder renal insufficiency affects the prognosis. The purpose of this study was to investigate the categorized impact of estimated glomerular filtration (eGFR) on the outcomes of patients with DFU.

DESIGN AND METHODS

Three hundred and sixty-six DFU patients hospitalized in a Chinese tertiary hospital were recruited and classified into 4 groups according to the eGFRs as follows: normal (≥90), mildly reduced (60-89), moderately reduced (30-59), and severely reduced (<30). These patients were followed-up for an average of 37 months to observe the outcomes, including ulcer healing, amputation, ulcer recurrence, cardiac or cerebrovascular events and death. The associations between eGFR and the outcomes were analysed by Cox proportional-hazards models.

RESULTS

Compared to patients with normal eGFR, patients with moderately reduced eGFR had higher risk of healing failure (hazard ratio (HR) = 2.08, 95% confidence interval (CI): 1.13-3.82), cardiac events (HR = 5.25, 95% CI: 2.17-12.89) and death (HR = 3.54, 95% CI: 1.36-9.20). Severely reduced eGFR was associated with higher incidence of healing failure (HR = 2.84, 95% CI: 1.25-6.49) and death (HR = 4.45, 95% CI: 1.23-16.07). The impact of eGFR on ulcer recurrence and cerebrovascular events was not observed in all groups.

CONCLUSIONS

Moderately and severely reduced eGFR in patients with DFU were independent predictors for poor prognoses of both the limbs and the patients.

Comparison of the risk of non-traumatic lower extremity amputation between haemodialysis and peritoneal dialysis patients with end-stage renal disease

AIM

We used insurance claims data of Taiwan to compare the risk of non-traumatic lower extremity amputation between haemodialysis (HD) and peritoneal dialysis (PD) patients.

METHODS

We identified 77 669 HD patients and 10 035 PD patients without prior amputation from 2000 to 2010. Incidence rates and hazard ratios (HRs) of lower extremity amputation, and subsequent 30-day mortality after amputation were evaluated up to 31 December 2011.

RESULTS

There were 2427 and 216 patients undergoing lower extremity amputation during follow-up in the HD and PD groups with incidence rates of 8.35 and 5.79 per 1000 person-years, respectively. Compared with the HD group, the overall adjusted HR of lower extremity amputation for the PD group was 1.27 (95% CI = 1.10-1.46). The impact of diabetes status on the risk of lower extremity amputation interacted with dialysis modality significantly (P < 0.001). Compared with the corresponding HD patients, the PD patients with diabetes had an adjusted HR of 1.44 (95% CI = 1.24-1.67) for amputation, whereas those without diabetes had an adjusted HR of 0.58 (95% CI = 0.36-0.95). The subsequent 30-day mortality rates after amputation were not significantly different between the HD and PD groups (8.45% vs. 9.72%) with an adjusted odds ratio of 1.41 (95% CI = 0.87-2.28, PD versus HD).

CONCLUSION

Compared with corresponding HD patients, the amputation risk is higher for PD patients with diabetes, while the risk is lower for PD patients without diabetes. Dialysis patients have a high 30-day mortality risk after amputation.

Haemodialysis Impairs the Human Microcirculation Independent from Macrohemodynamic Parameters

Hemodynamic changes during haemodialysis are common. Often these changes are associated with symptoms that are thought to be the result of reduced microcirculatory blood flow and oxygen delivery. The microcirculatory effect of hemodialysis is scarcely researched, though of possible influence on patient outcome. New techniques have become available to visualise and analyse microvascular blood flow. We performed an observational study using Sidestream Dark Field imaging, a microscopic technique using polarised light to visualise erythrocytes passing through sublingual capillaries, to analyse the effect of haemodyalisis on central microvascular blood flow. We showed that there is a substantial impairment of microvascular blood flow and a discrepancy between micro- and macro-vascular parameters.

Changes in skeletal muscle microcirculation after a hemodialysis session correlates with adequacy of dialysis

Background

Monitoring of the microcirculation may add additional information in terms of improving the adequacy of hemodialysis (HD) for patients. Withdrawal of liquid and complement activation during a HD session reduces the external pressure on the microcirculation and leads to an increased dilatation of the peripheral capillaries. The purposes of this study were to assess the effect of a single HD or hemodiafiltration session on the thenar microcirculation in patients with end-stage renal disease (ESRD) with or without diabetes, investigate the possible relationship between changes in the microcirculation and adequacy of dialysis (including Kt/V and parameters indicating secondary hyperparathyroidism), and compare microcirculation measurements obtained from patients with ESRD and those from healthy controls.

Methods

This pilot prospective observational study including eleven patients with ESRD on maintenance HD (nine men of mean age 73±10.5 years, ten [91%] with hypertension), nine patients with ESRD on maintenance hemodiafiltration (six men of mean age 65.5±13.2 years, five [55.5%] with diabetes and four [44.5%] with hypertension), and eight healthy volunteers. Two paired microcirculation assessments were recorded for each HD patient before and after a dialysis session. Near infrared spectroscopy and the vascular occlusion test were used to assess the microcirculation, and blood work samples were collected before and after dialysis when the pump slowed down.

Results

Patients with ESRD showed an increase in thenar cell metabolism at rest after a 4-hour HD session, and changes in cell metabolism correlated with the Kt/V of the session. Pre-dialysis tissue oxygen saturation over the 4-hour HD session correlated with pre-dialysis serum calcium and parathyroid hormones. Vascular reactivity was lower in ESRD patients receiving HD or hemodiafiltration than in healthy controls.

Conclusion

Improvement in skeletal muscle microcirculation noted after a HD session was related to adequacy of dialysis. Evaluation of the microcirculation may provide additional information for management of patients on HD and identify novel targets for treatment. These preliminary findings need to be tested using a larger data set.

Detection of microcirculatory impairment by transcutaneous oxymetry monitoring during hemodialysis: an observational study

Background

Little is known about the effects of intermittent hemodialysis on microcirculatory perfusion. The aim of this study is to assess the effects of hemodialysis on microvascular perfusion using transcutaneous oxymetry (TCPO2).

Methods

In this observational study, hourly TCPO2 measurements were performed during hemodialysis sessions. Ankle brachial index (ABI) was carried out to classify patients according their vascular condition.

Results

50 patients (mean age 70 ± 8 years old) were enrolled. Mean TCPO2 decreased significantly on average 23.9% between start and finish of hemodialysis. Severe ischemia (TCPO2 < 30 mmHg) and critical ischemia (TCPO2 < 10 mmHg) occurred during dialysis in 47.1% and 15.5% respectively. Critical ischemia occurred only in limbs with ABI < 0.9 (8.3%) or > 1.3 (28%). Patients with critical ischemia experienced a significantly larger decline in mean blood pressure (32.4 ± 26.1 mmHg vs 12.7 ± 10.7 mmHg; P = 0.007) and a more pronounced ultrafiltration (45.55 ± 16.9 ml/kg vs 35.17 ± 18.2 ml/kg; P = 0.04) compared to patients without ischemia. Clinical outcomes (death or vascular procedures) were five times more frequent in patients who had developed critical ischemia (55.7% vs 10.1% P = 0.01). The elevated age of patients, the low basal value of TCPO2, and the occurrence of critical ischemia were more frequently associated with clinical outcome (P = 0.03, P = 0.048, P = 0.01 respectively).

Conclusions

This study demonstrates that hemodialysis induces microcirculatory injury, dependent on blood pressure reduction, peripheral vascular state and ultrafiltration. The occurrence of critical ischemia is associated to pejorative patient outcome and therefore, TCPO2 seems to be useful to avoid potential distal tissue damage during hemodialysis.

Early utilization of hypertonic peritoneal dialysate and subsequent risks of non-traumatic amputation among peritoneal dialysis patients: a nationwide retrospective longitudinal study

BACKGROUND

The hemodialysis (HD) population has a particularly high incidence of amputation, which is likely associated with decreased tissue oxygenation during HD. However, information about the risk factors leading to amputation in peritoneal dialysis (PD) patients is limited. Here, we have investigated the association between the use of hypertonic peritoneal dialysate (HPD) and subsequent amputation in PD patients.

METHODS

Based on the data from the Taiwan National Health Insurance research database, this observational cohort study enrolled 203 PD patients who had received HPD early during treatment and had not undergone amputation and 296 PD controls who had not undergone amputation. Subjects were followed through until the end of 2009 and the event rates of new non-traumatic amputation were compared between groups.

RESULTS

The incidence of amputation was 3 times higher for the HPD cohort than for the comparison cohort (23.68 vs. 8.01 per 1000 person-years). The hazard ratio (HR) for this group, estimated using a multivariable Cox model, was 2.48 (95% confidence interval [CI] = 1.06-5.79). The HR for patients with both diabetes and early adoption of HPD increased to 44.34 (95% CI = 5.51-357.03), compared to non-HPD non-diabetic PD controls.

CONCLUSION

Early utilization of HPD in PD patients is associated with increasing risk of amputation; this risk considerably increases for those with concomitant diabetes.

Prevalence of risk factors for foot ulceration in patients with end-stage renal disease on haemodialysis

BACKGROUND

End-stage renal disease (ESRD) has been associated with foot ulceration and lower extremity amputation (LEA). However, the underlying risk factors for foot ulceration have received limited attention in this population.

AIM

The aim of this study was to investigate the prevalence and type of risk factors for foot ulceration present in patients with ESRD on haemodialysis without the coexistence of diabetes mellitus (DM).

METHODS

One hundred and ninety participants with ESRD and/or DM were recruited over a 6-week period. Participants were allocated into one of three groups: (i) ESRD without DM; (ii) DM without ESRD; and (iii) coexisting ESRD and DM. Participants were screened for the risk factors for foot ulceration. Statistical comparisons were made between the three groups for both the prevalence and type of risk factors using a Fisher's exact test.

RESULTS

Risk factors for foot ulceration were found to be highly prevalent in the ESRD population. Participants with both ESRD and DM exhibited statistically significant differences in risk factor presentation for peripheral neuropathy (P= 0.033), vascular insufficiency (P= 0.001) and footwear (P= 0.037) in comparison with participants with DM alone.

CONCLUSION

There are high prevalence rates of risk factors for foot ulceration in the ESRD population on haemodialysis and are comparable with those with DM. Individuals with coexisting ESRD and DM have an even greater risk for foot ulceration and LEA. This highlights the importance that regular foot screening, preventative education and treatment are necessary for patients with ESRD potentially to reduce the risk of foot ulcerations and LEAs.

Prevalence of risk factors for foot ulceration in a general haemodialysis population

It is well documented that diabetic foot ulceration contributes to increased morbidity and mortality associated with renal replacement therapy. Much less is known about the risk of foot ulceration and lower limb amputation in the non-diabetic dialysis population. The aim of this study was to determine if the prevalence of risks factors for lower limb amputation in a stable haemodialysis population was greater in the diabetic cohort compared with the non-diabetic cohort. The study design is a prospective observational cohort study. Sixty patients attending a satellite haemodialysis unit in Cardiff were invited to have a comprehensive foot assessment as part of a Podiatry service review. The medical notes and hospital information system were used to identify the diabetic cohort. Patients were classified according to diabetic status (diabetic versus non-diabetic). The Renal Foot Screening Tool was developed to prospectively identify risk factors associated with foot ulceration. The assessment included peripheral neuropathy (PN), peripheral arterial disease (PAD) and foot pathology (FP). Fifty-seven patients gave informed verbal consent prior to inclusion. Risk factors for foot ulceration were recorded at baseline in the diabetic (n = 24) and non-diabetic (n = 33) groups and mortality data was revisited after a 3-year period. FP was identified in 79% of patients. Eighteen per cent of the non-diabetic patients had PN. PAD was identified in 45% of diabetic and 30% of non-diabetic patients. Forty-nine per cent of the total cohort had ≥2 of the 3 independent risk factors for foot ulceration (16/24 diabetic versus 12/33 non-diabetic). The presence of PAD and PN was predictive of mortality independent of age. The limitations of this study are its small sample size and patients were from a single satellite dialysis unit. There was a high prevalence of risk factors for foot ulceration in this population, which were not confined to the diabetic cohort. These findings suggest that non-diabetic patients on haemodialysis therapy are also at risk of developing foot ulceration. Further work on strategies to monitor and prevent FP in this high-risk cohort is needed to minimize morbidity and mortality associated with foot ulceration.

[A case of phlebosclerotic colitis in a hemodialysis patient]

Phlebosclerotic colitis is a rare disease of intestinal ischemia caused by calcified peripheral mesenteric veins and a thickened colonic wall, differentiating it from the typical ischemic colitis. A 68-year-old man who was undergoing hemodialysis presented with hematochezia and abdominal pain. Colonoscopic findings showed typical dark purple-colored edematous mucosa. Linear calcifications in the colon were noted on both a plain abdominal radiolography and abdominal computer tomography. These findings suggested that the patient suffered from phlebosclerotic colitis. Following bowel rest and fluid therapy, there was full recovery. We herein report a rare case of phlebosclerotic colitis in a hemodialysis patient and include a review of the relevant literature.

Disturbances of skin microcirculation in lower extremities in diabetes mellitus:a pathophysiological phenomenon or an object for therapy?

Functional microcirculatory abnormalities in the foot have been given much attention in the recent years for their potential pathogenetic role in thedevelopment of diabetic neuropathy and diabetic foot syndrome. This paper reviews data on the disturbances of skin microcirculation in lower extremitieswith reference to the role of neuropathy and endothelial dysfunction in this pathology. Possible relationships between end-stage renal disease, highplantar pressure and compromised skin microcirculation are discussed. The influence of several drugs on foot skin microcirculation and prospects fortheir use for therapeutic purposes are considered.

The impact of creatinine clearance on the outcome of diabetic foot ulcers in north Indian tertiary care hospital

AIM

Wound healing has been reported to be poor in diabetic patients with impaired kidney functions that usually accompanies retinopathy and neuropathy. The insensitive foot is vulnerable to repeated trauma and development of ulcer precedes 70-80% of non-traumatic lower extremity amputation. The present study was aimed to study the impact of creatinine clearance (CCre) on the outcome of diabetic foot ulcers (DFU).

MATERIALS AND METHODS

Data from 162 DFU patients admitted to Rajiv Gandhi Centre for Diabetes and Endocrinology of J.N. Medical College, Aligarh Muslim University, Aligarh, India, between December 2009 and March 2011 were analyzed. Detailed history and patient's profile, grade of DFU, co-morbidities and complications, laboratory data, microbiological profile and final outcome were collected. CCre was calculated according to MDRD formula.

RESULTS

The study revealed that, DFU healing was worst in patients with decreased CCre than in those who had normal CCre. Other factors associated with poor outcome were, higher grade of ulcer, infection type (subcutaneous and osteomyelitis) and biofilm infection. Amputation rates were also found to be higher in those with poor renal functions.

CONCLUSIONS

The results suggest that CCre is an important factor affecting wound healing in patients with DFUs. The automatic reporting of eGFR each time a serum creatinine concentration is requested will increase the awareness of significant kidney dysfunction in clinical practice especially in DFU patients and appropriate measures will improve the outcome.

Plasma albumin levels correlate with decreased microcirculation and the development of skin defects in hemodialyzed patients

OBJECTIVES

Difficulty healing wounds and skin defects is a frequent problem in patients on chronic hemodialysis (HD) because of malnutrition, inflammation, and atherosclerosis (MIA) syndrome. The aim of the present study was to estimate the influence of peripheral blood flow changes during HD on the development of foot defects and its relationship to plasma albumin levels.

METHODS

Peripheral skin blood flow was measured using a laser Doppler line scanner in 10 different areas of the dorsal part of the instep and the toes of each foot before and during HD with ultrafiltration (897 +/- 465 mL/procedure) in 31 HD patients (10 female, 21 male; age 36-79 y, body mass index = 28 +/- 5.0). No skin defects or apparent acute disease or infection were detected in any patient at the time of laser Doppler line scanner measurement. The feet of the patients were clinically re-examined carefully over the next 18 mo.

RESULTS

We found a significant and constant decrease of skin blood flow during the HD procedure (P < 0.001). Skin blood flow was significantly correlated with serum albumin level both before HD (r = 0.36, P = 0.05) and during HD (r = 0.47, P = 0.007). Skin defects developed in 11 patients, with significantly lower skin blood flow during the 18-mo follow-up period. A significantly larger number of patients who had normal perfusion remained defect-free in comparison to patients with critical perfusion (93% versus 38%, P = 0.002, Kaplan-Meier analysis).

CONCLUSION

Skin blood flow may be impaired in HD patients. The apparent malnutrition and inflammation in HD patients are likely responsible for the decreased skin blood flow and the development of the difficulty to heal skin defects and wounds.

The effect of creatinine clearance on the short-term outcome of neuropathic diabetic foot ulcers

Reduced creatinine clearance is related to an increased risk for diabetic foot ulcer development. Wound healing has been reported to be worse in diabetic patients with impaired kidney functions than general diabetic population. This study aimed to investigate the effect of creatinine clearance on the short-term outcome of neuropathic diabetic foot ulcers. Data from 147 neuropathic diabetic foot ulcer episodes were included in this observational study. Patients were admitted to Dokuz Eylul University Hospital between January 2003 and June 2008. Patients were excluded if they had limb ischemia. Diabetic nephropathy was investigated by 24h urinary albumin excretion and serum creatinine levels. Creatinine clearance was calculated according to Cockcroft-Gault formula. Foot ulcers were followed up for 6 months to determine the outcome. Our short-term follow-up revealed that neuropathic diabetic ulcers healed worse in patients with decreased creatinine clearance than in those who had normal creatinine clearance. Amputation rates were also found to be higher. Our results suggest that creatinine clearance is an important factor affecting wound healing in patients with neuropathic diabetic foot ulcers.

Diabetic foot disease in people with advanced nephropathy and those on renal dialysis

Among the spectrum of risk for diabetic foot disease conferred by chronic kidney disease (CKD), end-stage renal disease (ESRD) has emerged as a novel independent risk factor. Apart from the classical triad of neuropathy, infection, and peripheral arterial disease that operate in these individuals, the risk is further compounded by inadequate foot self-care by patients and by dialysis centers not providing onsite foot care, as medical priorities are diverted to the dialysis itself. Consequently, the burden of diabetic foot disease has increased in the CKD and ESRD population as exemplified by high ulceration, amputation, and foot-related mortality rates. Current guidelines on foot care in diabetes should recognize advanced CKD and ESRD/dialysis as a separate risk factor for foot disease to alert professionals and highlight the opportunity for prevention. Recent studies have demonstrated improved foot outcomes when chiropody programs are instituted within dialysis units.

Evaluation of skin microcirculation during hemodialysis

BACKGROUND

Cardiovascular mortality in hemodialysis (HD) patients remains high despite improvements in HD technique such as dialysis adequacy, dialysis fluid purity, and membrane biocompatibility. Optimal fluid balance to maintain optimal hemodynamic stability during hemodialysis (HD) procedure is essential. At the present time, hemodynamic stability is conventionally assessed as stability of macrocirculation, especially as maintenance of systemic blood pressure with no attention paid to peripheral perfusion. Peripheral ischemic vascular disease represents a serious problem with high mortality and morbidity. We estimated skin microcirculation changes during HD using new device, Laser Doppler Line Scanner (Moor Instruments, Devon, UK).

AIMS

The aims were to introduce the novel method of detection of skin perfusion changes during hemodialysis and to evaluate possible relationship of these to ultrafiltration as well as to selected biochemical characteristics.

METHODS

In 36 hemodynamically stable patients, we performed paired measurements of skin blood flow in both hands before and during HD with registering the time of dialysis and the total ultrafiltration achieved.

RESULTS

We found a significant decrease in a majority of the evaluated areas. However, the skin blood flow change was not homogenous as it decreased more on the fingers.

CONCLUSION

To our knowledge, this is the first study when the microcirculatory changes during hemodialysis are demonstrated and evaluated in large skin surface area, and showing not only a decrease in a majority of areas but also the heterogeneity of the changes.

Medial arterial calcification in diabetes and its relationship to neuropathy

Calcification of the media of arterial walls is common in diabetes and is particularly associated with distal symmetrical neuropathy. Arterial calcification also complicates chronic kidney disease and is an independent risk factor for cardiovascular and all-cause mortality. The term calcification is not strictly accurate because the morphological changes incorporate those of new bone formation, i.e. ossification. The processes are complex, but are closely related to those involved in bone homeostasis, and it is relevant that calcification of the arterial wall and osteopenia often co-exist. One particular factor linked to the development of arterial calcification is distal symmetrical neuropathy; indeed, it has been suggested that neuropathy explains the distal distribution of arterial calcification in diabetes. It has also been suggested that the link with neuropathy results from loss of neuropeptides, such as calcitonin gene-related peptide, which are inherently protective. The association between distal symmetrical neuropathy and calcification of the arterial wall highlights the fact that neuropathy may be an independent risk factor for cardiovascular mortality.

Microcirculatory changes and skeletal muscle oxygenation measured at rest by non-infrared spectroscopy in patients with and without diabetes undergoing haemodialysis

Introduction

Haemodialysis has direct and indirect effects on skin and muscle microcirculatory regulation that are severe enough to worsen tolerance to physical exercise and muscle asthenia in patients undergoing dialysis, thus compromising patients' quality of life and increasing the risk of mortality. In diabetes these circumstances are further complicated, leading to an approximately sixfold increase in the incidence of critical limb ischaemia and amputation. Our aim in this study was to investigate in vivo whether haemodialysis induces major changes in skeletal muscle oxygenation and blood flow, microvascular compliance and tissue metabolic rate in patients with and without diabetes.

Methods

The study included 20 consecutive patients with and without diabetes undergoing haemodialysis at Sant Andrea University Hospital, Rome from March to April 2007. Near-infrared spectroscopy (NIRS) quantitative measurements of tissue haemoglobin concentrations in oxygenated [HbO₂] and deoxygenated forms [HHb] were obtained in the calf once hourly for 4 hours during dialysis. Consecutive venous occlusions allowed one to obtain muscular blood flow (mBF), microvascular compliance and muscle oxygen consumption (mVO₂). The tissue oxygen saturation (StO₂) and content (CtO₂) as well as the microvascular bed volume were derived from the haemoglobin concentration. Nonparametric tests were used to compare data within each group and among the groups and with a group of 22 matched healthy controls.

Results

The total haemoglobin concentration and [HHb] increased significantly during dialysis in patients without and with diabetes. Only in patients with diabetes, dialysis involved a [HbO₂], CtO₂ and increase but left mVO₂ unchanged. Multiple regression StO₂ analysis disclosed a significant direct correlation of StO₂ with HbO₂ and an inverse correlation with mVO₂. Dialysis increased mBF only in diabetic patients. Microvascular compliance decreased rapidly and significantly during the first hour of dialysis in both groups.

Conclusions

Our NIRS findings suggest that haemodialysis in subjects at rest brings about major changes in skeletal muscle oxygenation, blood flow, microvascular compliance and tissue metabolic rate. These changes differ in patients with and without diabetes. In all patients haemodialysis induces changes in tissue haemoglobin concentrations and microvascular compliance, whereas in patients with diabetes it alters tissue blood flow, tissue oxygenation (CtO₂, [HbO₂]) and the metabolic rate (mVO₂). In these patients the mVO₂ is correlated to the blood supply. The effects of haemodialysis on cell damage remain to be clarified. The absence of StO₂ changes is probably linked to an opposite [HbO₂] and mVO₂ pattern.

Changes in the volume status of haemodialysis patients are reflected in sublingual microvascular perfusion

BACKGROUND

After the introduction of sidestream darkfield imaging (SDF) of the microcirculation, it has become clear that in sepsis, microcirculatory alterations can exist in the absence of systemic haemodynamic abnormalities. However, it is unclear whether this phenomenon also occurs in the treatment of end-stage kidney disease (ESKD) where alterations in the volume status of patients occur during dialysis. We tested the hypothesis that volume changes during dialysis directly affect the perfusion of the microcirculation in a group of adult haemodialysis patients. Secondly, we evaluated microcirculatory response to autotransfusion using the Trendelenburg position (TP).

METHODS

Patients who were on chronic intermittent haemodialysis were assessed for sublingual microvascular flow by SDF imaging pre- and post-TP, performed before and after ultrafiltration (UF). Sublingual microvascular flow was estimated using a semi-quantitative microvascular flow index (MFI) in small (diameter <25 microm, which includes capillaries), medium (25-50 microm) and large-sized (50-100 microm) microvessels (no flow: 0, intermittent flow: 1, sluggish flow: 2 and continuous flow: 3). Changes were evaluated with the non-parametric paired Wilcoxon test. P < 0.05 was judged to indicate a significant difference.

RESULTS

Thirty-nine adult patients took part in the study. The underlying diseases causing ESKD were predominantly hypertension (HT, n = 10), diabetes mellitus (DM, n = 7) or both (n = 3). At the start of UF, microvascular flow did not change significantly by TP. After completion of UF, MFI had decreased significantly in all types of microvessels (P < 0.001). After UF (median volume extraction 2.49l), MFI was lower than that at the start of UF and increased in most patients after TP (P < 0.001) in all categories of vessels. Changes were most prominent in the smallest microvessels.

CONCLUSIONS

Sublingual microvascular perfusion is reduced by UF and can be restored temporarily using autotransfusion by TP due to increased venous return. SDF imaging is able to detect these volume changes. SDF imaging and TP could become a useful bedside tool to evaluate the patient's (microvascular) volume status and response to therapy in dialysis or intradialytic hypotension.

Haemodialysis is associated with changes in cutaneous microcirculation in diabetes mellitus

AIMS

To examine the cutaneous microcirculation on the dorsum of the foot before, during and after haemodialysis in diabetic and non-diabetic patients.

METHODS

Fourteen age-matched patients (seven diabetic, seven non-diabetic) without active foot ulceration were studied. Cutaneous microcirculation was assessed using a micro-lightguide spectrophotometer to measure venous oxygen saturation and relative blood flow determined at two tissue depths: 2 and 6 mm. Cumulative relative changes of each parameter during haemodialysis were calculated as area under the curve. Differences between and within the groups were calculated by Mann-Whitney U-test and anova following post hoc testing, respectively.

RESULTS

At baseline, relative blood flow at 6 mm tissue depth was significantly greater in diabetic patients (P = 0.048). Thirty minutes after the end of dialysis, relative blood flow at 2 and 6 mm tissue depth was significantly higher in non-diabetic patients (P = 0.048 and P = 0.001). Mean cumulative relative changes in venous oxygen saturation and relative blood flow at 2 mm as well as 6 mm tissue depth were positive for non-diabetic subjects and negative for diabetic patients.

CONCLUSIONS

Haemodialysis is associated with changes in cutaneous microcirculation, which differ between people with and without diabetes. In those without diabetes, we found an increase in blood flow during haemodialysis, whereas blood flow was reduced in diabetic patients. This may be the result of abnormal vasomotor regulation due to distal neuropathy.

The diabetic foot in end stage renal disease

Diabetic foot lesions remain a major cause of morbidity in patients with renal failure, especially those on dialysis. Foot complications are encountered at a more than twofold frequency in diabetic patients with end-stage renal disease, and the rate of amputations is 6.5-10 times higher in comparison to the general diabetic population. The causal pathways of the diabetic foot in renal failure are multiple and inter-related. Three major pathologies--neuropathy, ischemia, and infection--are the main contributory factors. Increased awareness of this condition and careful clinical examination are indispensable to avoid serious complications. Appropriate management needs to address all contributory factors. Treatment options include revascularization, off-loading to relieve high-pressure areas, and aggressive control of infection. Equally important is the collaboration between health care providers in a multidisciplinary foot care setting. Moreover, patient education on the measures required to achieve both primary and secondary prevention is of great value. Certainly, technical innovations have made considerable progress possible, but there is a need for further improvement to reduce the number of amputations.