Authors and co-researchers have continued various clinical practice and research for years. Among them, various treatments are conducted including type 2 diabetes (T2D), cerebral vascular accident (CVA), ischemic heart disease (IHD), peripheral artery disease (PAD), chronic kidney disease (CKD), hemodialysis (HD), and other diseases [1]. Our hospital has HD department, and lots of HD patients have been treated. They have generalized problems in vascular diseases [2,3].

Especially, HD patients have frequent PAD in lower extremities, leading to crucial condition. Most severe situation would become acute limb ischemia (ALI) that progressively worsens within 2 weeks [4]. Due to comorbid conditions including CVA, IHD, the mortality rate remains high at 15–20% [5]. Before ALI, chronic vascular problem has been observed, which was formerly called as arteriosclerosis obliterans (ASO), and recently called as lower extremity artery disease (LEAD) [6]. For the diagnosis of LEAD, popular examination is known for ankle-brachial index (ABI? [7]. Recent trends introduced Wound, Ischemia, and foot Infection (WIfI) classification, which is from the Society for Vascular Surgery WIFI [8]. It would be useful for the management of PAD cases.

Furthermore, useful measurement of skin perfusion pressure (SPP) has been recently introduced to clinical practice. SPP refers to the perfusion pressure in the microcirculation of skin tissue, and it seems to be an index for maintaining material exchange. SPP can be applied for the assessment the severity of chronic limb-threatening ischemia (CLTI) and to decision of treatment options [9]. Authors have reported several articles about CKD, HD, and related clinical matters. We have tried to evaluate the status of PAD for HD patients by using SPP examination. From our experience, general data of SPP for HD patients with some related perspectives will be described in this article.

Patients and Methods

In this study, patients have received regular HD three times a week for years. We analyzed data from 41 consecutive SPP tests that have been recently performed at Kanaiso Hospital. They received SPP exams in right and left feet. Among them, 5 cases showed blank data of either right or left foot because of probable occlusive status from their PAD situation. We have omitted 5 cases, and 36 cases were investigated for statistical examination, associated with complete data of plantar/dorsal sites of right/left sides. Among 36 applicants, male and female were 24 and 12 cases, respectively.

Methods included the measurement of SPP by the clinical apparatus of PAD4000 developed by Kaneka Medical Product, Japan, which is product No. 22500BZX00516000 [10]. It can measure 0.0-4.1% skin perfusion stream, 0-250 mmHg as SSP, 0-80 mm of maximum amplitude, and 1-8 Hz of responsive frequency as air volume pulse wave.

Ethical Standards

Current protocol complied with the usual ethical guideline for Declaration of Helsinki [11]. In addition, some comments were found with the protected regulation for human information. This principle has been associated with the ethic regulation for actual practice and research for human cases. Some guidelines are informed by Japanese Ministry. It included the Ministry of Health, Labor and Welfare and the Ministry of Education, Culture, Sports, Science Technology, Japan. The authors and collaborators established the ethic committee for this patient, which is in Kanaiso Hospital, Tokushima, Japan. The committee has clinical and also legal personnel, including hospital director, internists, nurse, dietitian, pharmacist, and also legal professional. These members have discussed in satisfactory manner, agreed for the research protocol, and gained the written informed consent from current case.

Results

Current study included 36 HD patients (M/F 24/12), in which general data were analyzed. Their age showed 75.8 +/- 8.9 years old (mean +/- SD) with 76 years old in median. Detail quartile data of 36 cases were summarized in Table 1. The relationship between age and HD duration period was calculated in Figure 1 with negative significant correlation (p<0.05). The applicants were divided into 2 groups with 18 cases each (Figure 2). Younger group with 49-75 years showed wider distribution of SPP values than those of older group with 76-91 years. Furthermore, the applicants were divided into 3 groups with 12 cases each by the HD duration years, in which median value showed 4.9, 10.6 and 22.7 years, respectively (Figure 3).

In long HD group, SPP values showed the tendency of lower SPP levels than standard range of 50 mmHg. By analyzing the SPP value in left plantar and left amplitude level, short history (Hx) group showed rather scattered distribution, and long Hx group showed small narrower distribution (Figure 4).

Discussion

A meta-analysis with integrated data of some cohort studies showed that decreased ABI (<0.90) would be 1.1% [7]. From international systematic review, PAD has some main risk factors leading to LEAD, including smoking, age, diabetes, hypertension, dyslipidemia and CVA [12]. Among these situations, SPP becomes a reliable biomarker [13]. The interesting report has been found from an epidemiological study in Japan. It was the large study for PAD, named as Surveillance of Cardiovascular Events in Antiplatelet-Treated Arteriosclerosis Obliterans Patients in Japan (SEASON). As a result, prevalence of risk factors for PAD was shown as follows: they are 16.2% for smoking, 61.5% for hypertension, 38.3% for diabetes, 38.8% for dyslipidemia, 29.7% for heart disease, 17.1% for cerebrovascular disease, and 14.3% for CKD [14]. Using WLFI classification, the target limb is evaluated based on three factors of tissue loss, ischemia, and foot infection [15]. CLTI is diagnosed in adults who have been objectively diagnosed with LEAD and who have a variety of clinical symptoms [16].

This study included HD patients undergoing conventional standard treatment. To reflect the situation in daily medical practice, the subjects included 41 HD patients who had undergone continuous SPP examinations up to the present. However, five HD patients were excluded from the analysis because data on both sides could not be obtained due to PAD in the lower limbs. The data in this study were analyzed for cases with all data available, and the average and median of all 36 cases are shown (Table 1).