Effects of the ankle-brachial blood pressure index and skin perfusion pressure on mortality in hemodialysis patients

Laser Doppler blood flowmeter as a useful instrument for the early detection of lower extremity peripheral arterial disease in hemodialysis patients: an observational study

BACKGROUND

A simpler method for detecting atherosclerosis obliterans is required in the clinical setting. Laser Doppler flowmetry (LDF) is easy to perform and can accurately detect deterioration in skin perfusion. We performed LDF for hemodialysis patients to determine the correlations between blood flow in the lower limbs and peripheral arterial disease (PAD).

METHODS

This retrospective study included 128 hemodialysis patients. Patients were categorized into the non-PAD group (n = 106) and PAD group (n = 22), 14 early stage PAD patients were included in the PAD group. We conducted LDF for the plantar area and dorsal area of the foot and examined skin perfusion pressure (SPP) during dialysis.

RESULTS

SPP-Dorsal Area values were 82.1 ± 22.0 mmHg in the non-PAD, and 59.1 ± 20.3 mmHg in PAD group, respectively (p < 0.05). The LDF-Plantar blood flow (Qb) values were 32.7 ± 15.5 mL/min in non-PAD group and 21.5 ± 11.3 mL/min in PAD group (p < 0.001). A total of 21 non-PAD patients underwent LDF before and during dialysis. The LDF-Plantar-Qb values were 36.5 ± 17.6 mL/min before dialysis and 29.6 ± 17.7 mL/min after dialysis (p < 0.05). We adjusted SPP and LDF for PAD using logistic regression, SPP-Dorsal-Area and LDF-P were significantly correlated with PAD (p < 0.05). The receiver-operating characteristic curve analysis indicated cut-off values of 20.0 mL/min for LDF-Plantar-Qb during dialysis.

CONCLUSION

LDF is a simple technique for sensitive detection of early-stage PAD. This assessment will help physicians identify early-stage PAD, including Fontaine stage II in clinical practice, thereby allowing prompt treatment.

Brachial-ankle pulse wave velocity, cardio-ankle vascular index, and prognosis

Background

Brachial–ankle pulse wave velocity (baPWV) and cardio-ankle vascular index (CAVI) are indices of arterial stiffness, and several studies have used these indices. However, there is no comprehensive review of these parameters in the prognostic significance.

Methods

The aim of this study was to review the articles exploring the prognostic significance of these parameters. Articles demonstrating independent significance after multivariate analysis on the Cox proportional hazards model were defined as “successful.” The success rate was compared using Fisher’s exact test. In addition, multivariate logistic regression analysis was performed to explore the independent determinants of the success of prognostic prediction.

Results

The success rate of the baPWV articles (65.7% [46/70]) tended to be higher than that of the CAVI articles (40.0% [6/15]; P=0.083). Multivariate analysis demonstrated that log (number of patients) (OR 11.20, 95% CI 2.45–51.70, P=0.002) and dialysis population (OR 0.28, 95% CI 0.08–0.94, P=0.039) were positive and negative independent determinants of the success of prognostic prediction, respectively. In addition, after redefining two studies as the absence of arteriosclerosis obliterans (ASO) exclusion, baPWV (OR 3.36, 95% CI 0.86–13.20, P=0.083) and the existence of exclusion criteria of ASO (OR 3.08, 95% CI 0.96–9.93, P=0.060) exhibited statistical tendency in the multivariate analysis.

Conclusion

This study demonstrated that the number of study participants and dialysis population were the independent determinants of the success of prognostic prediction. This study also showed the importance of exclusion criteria of ASO when using these indices. In addition, a prospective large-scale study to confirm the superiority in the prognostic prediction of these indices is warranted.

Pitfalls in the ankle-brachial index and brachial-ankle pulse wave velocity

Background

The ankle-brachial index (ABI) and pulse wave velocity (PWV) are indices of atherosclerosis and arterial stiffness. The Japan-made measuring devices of those indices have spread widely because of their convenience and the significance of the parameters. However, studies that comprehensively discuss the various pitfalls in using these indices are not available.

Methods

This study presents several representative pitfalls in using the ABI and brachial-ankle PWV (baPWV) by showing the result sheets of the device, “the Vascular Profiler”. Furthermore, some considerations when utilizing these indices in the future are also discussed.

Results

Several diseases such as arteriosclerosis obliterans (ASO), arterial calcification in the lower limb, arterial stenosis in the right upper-limb, aortic valve diseases, arterial stenosis in the upper-limb of the contralateral side of the hemodialysis access, are the representative pitfalls when evaluating ABI and baPWV. Moreover, a measurement error is found to actually exist. Furthermore, same phenomena are considered most likely to occur when using other similar indices and devices.

Conclusion

The ABI and baPWV are the useful and significant biomarkers. Nevertheless, caution is sometimes necessary when interpreting them. Moreover, rigorous patient exclusion criteria should be considered when using those indices in the severely conditioned patient population. And the results of this study can be applied to enhance the literacy using other indices, such as the cardio-ankle vascular index and other similar devices.

Long-Term Survivor Characteristics in Hemodialysis Patients with Type 2 Diabetes

BACKGROUND

Data concerning long-term mortality predictors among large, purely diabetic hemodialysis collectives are scarce.

METHODS

We used data from a multicenter, prospective, randomized trial among 1,255 hemodialysis patients with type 2 diabetes mellitus (T2DM) and its observational follow-up study. The association of 10 baseline candidate variables with mortality was assessed by Cox proportional hazards regression.

RESULTS

Overall, 103 participants survived the median follow-up of 11.5 years. Significant predictors of mortality were age (hazard ratio [HR] 1.03, 95% CI 1.02-1.04), cardiovascular (HR 1.42, 95% CI 1.25-1.62) and peripheral vascular disease (HR 1.55, 95% CI 1.36-1.76), higher hemoglobin A1c (HbA1c; HR 1.08, 95% CI 1.03-1.14), and loss of self-dependency (HR 1.20, 95% CI 1.03-1.39). Higher albumin (HR 0.72, 95% CI 0.59-0.89) and body mass index (BMI; HR 0.98, 95% CI 0.96-0.99) had protective associations. There was no significant association with sex, diabetes duration, and cerebrovascular diseases. Subgroup analyses by age and diabetes duration showed stronger associations of cardiovascular disease, HbA1c, albumin, BMI, and loss of self-dependency in younger patients and/or shorter diabetes duration. Loss of self-dependency and energy resources (albumin, BMI) increased mortality more severely in women, whilst the impact of cardiovascular and peripheral vascular diseases was more pronounced in men.

CONCLUSION

Long-term mortality risk in patients with T2DM on hemodialysis was associated with higher age, vascular diseases, HbA1c, loss of self-dependency, and low energy resources. Interestingly, it does not vary between sexes. Further individualized prognosis estimation and therapy should strongly depend on age, diabetes duration, and gender.

Skin Perfusion Pressure and the Prevalence of Atherothrombosis in Hemodialysis Patients

End-stage renal disease is associated with atherothrombosis (ATIS), which, in turn, can promote peripheral arterial occlusive disease (PAOD), coronary artery disease (CAD), and/or cerebrovascular disease (CVD). The aim of this study was to determine whether low plantar skin perfusion pressure (SPP) was related to ATIS among 122 patients receiving maintenance hemodialysis (HD) from March to November 2013 at our outpatient facility. We routinely measured SPP and used the value for analysis. In addition, we retrospectively evaluated the prevalence of ATIS with patients categorized to CAD, CVD, or PAOD groups. Of the 122 outpatients, ATIS was diagnosed in about half (N = 60, 49.2% vs. 62, 50.8%; average SPP, 56.6 vs. 72.9 mm Hg, respectively). These data show that SPP was significantly lower in patients with ATIS (difference, 16.3 mm Hg; P < 0.001) and there was a negative relationship between average SPPs and past history of ATIS complications. When the patients were stratified by the presence of diabetes mellitus, this trend was stronger. Particularly, receiver operating characteristic analysis of HD patients with diabetes revealed a cutoff point of 53.0 mm Hg and an area under the curve value of 0.84, with a sensitivity of 77.0% and specificity of 91.3%. Therefore, we concluded that SPP enables the evaluation of not only local PAOD, but also systemic ATIS. Moreover, we found that a cutoff point of 53.0 mm Hg was useful for detection of ATIS in HD patients.

Prediction of Development of Critical Limb Ischemia in Hemodialysis Patients

Hemodialysis (HD) patients with critical limb ischemia (CLI) suffer chronic inflammation and repeated infection, require intervention, and may have a protracted hospital stay. Therefore, early prediction is particularly important for management of CLI in patients with suspected peripheral artery disease. The purpose of this study is to develop a simple score for predicting the incidence of CLI in HD patients with suspected peripheral artery disease. The subjects were 139 asymptomatic patients receiving maintenance HD and with ABI <1.0. Multivariate logistic regression analysis was used to identify factors associated with development of CLI. These factors were subsequently weighted and integrated into a scoring system for the prediction of onset of CLI. Twenty-five patients had onset of CLI. Five factors selected from the multivariate model were weighted proportionally using their respective odds ratio (OR) for incidence of CLI (history of cerebral vascular disease, OR 6.42 [3 points]; diabetes, OR 3.92 [2 points]; hypoesthesia, OR 4.21 [2 points]; left ventricular ejection fraction <50%, OR 3.89 [2 points]; serum albumin <3.5 g/dL, OR 4.39 [2 points]). Three strata of risk were defined (low risk, 0 to 3 points; intermediate risk, 4 to 6 points; and high risk 7 to 11 points) with excellent prognostic accuracy for progression to CLI using the Kaplan-Meier method. Five factors were identified that increased the risk of progression to CLI in HD patients with suspected peripheral artery disease. A combination of those factors permitted establishment of three risk strata for accurate prediction of onset of CLI.

Perfusion index derived from a pulse oximeter can detect changes in peripheral microcirculation during uretero-renal-scopy stone manipulation (URS-SM)

Background

The objective of this study was to test the effect of removal of a ureteral obstruction (renal calculus) from anesthetized patients on the perfusion index (PI), as measured by a pulse oximeter, and on the estimated glomerular filtration rate (eGFR).

Patients and Methods

This prospective study enrolled 113 patients with unilateral ureteral obstructions (kidney stones) who were scheduled for ureteroscopy (URS) laser lithotripsy. One urologist graded patient hydronephrosis before surgery. A pulse oximeter was affixed to each patient's index finger ipsilateral to the intravenous catheter, and a non-invasive blood pressure cuff was placed on the contralateral side. Ipsilateral double J stents and Foley catheters were inserted and left indwelling for 24 h. PI and mean arterial pressure (MAP) were determined at baseline, 5 min after anesthesia, and 10 min after surgery; eGFR was determined at admission, 1 day after surgery, and 14 days after surgery.

Results

Patients with different grades of hydronephrosis had similar age, eGFR, PI, mean arterial pressure (MAP), and heart rate (HR). PI increased significantly in each hydronephrosis group after ureteral stone disintegration. None of the groups had significant post-URS changes in eGFR, although eGFR increased in the grade I hydronephrosis group after 14 days. The percent change of PI correlates significantly with the percent change of MAP, but not with that of eGFR.

Conclusion

Our results demonstrate that release of a ureteral obstruction leads to a concurrent increase of PI during anesthesia. Measurement of PI may be a valuable tool to monitor the successful release of ureteral obstructions and changes of microcirculation during surgery. There were also increases in eGFR after 14 days, but not immediately after surgery.