A well-functioning VA is the key to ensuring sufficient hemodialysis and to improving the prognosis of hemodialysis patients [2]. For various reasons such as complications, vascular exhaustion, technical and economic problems, some patients cannot choose arteriovenous access or catheters as VA for hemodialysis. DAP has the advantages of being used for emergency dialysis and low cost. One more choice means one more chance to live for hemodialysis patients.
Our results showed that there were 38(0.43%) patients received maintenance hemodialysis with DAP in 30 hemodialysis centers, Which was less than 1.8% of superficialization of artery reported by the Statistical Survey Committee of the Japanese Society for Dialysis Therapy among 172,244 patients surveyed [14]. The median duration of DAP was 1428 days with a interquartile range (141~ 2950 days), which not only solved the needs of temporary hemodialysis, but also met the requires of long-term hemodialysis in certain patients. When it comes to reasons for hemodialysis with DAP, 19 (50%) patients claimed to be unwilling to afford the cost of AVF creation or maintenance since DAP could maintain their hemodialysis treatment. All patients in this survey have already established vascular access before applying DAP for more than once, and even up to 7 times. AVFs are the preferred type of access, but the cost associated with creation and maintenance remains high [15]. The median annual overall cost for each hemodialysis patient was 87,125 Renminbi and more than one-third of the spending was related to VA maintenance [16]. In fact, both developing and developed countries bear the huge cost of VA maintenance [17]. Although the Chinese government is committed to having universal health coverage, as some medical insurance is voluntary, some patients fail to go through the procedures as required, which affects the reimbursement of medical expenses. In addition, the extra costs undoubtedly increase the burden on hemodialysis patients since their work ability was impaired [18]. Thus, patients would rather rely on DAP for treatment since the DAP could work successfully with little cost. Secondly, 39.5% of patients expressed the reason for DAP was that the matured arteriovenous fistula cannot be created because of the poor condition of vascular or cardiac function. The rapid growth of the aging population and the high prevalence of comorbidities, particularly diabetes mellitus and peripheral vascular disease, in patients requiring hemodialysis inevitably deteriorate the ability to construct and maintain a conventional AVF because of these patients’ insufficient vascular adaptability. In addition, an arteriovenous shunt can increase the heart burden. A decrease in systemic vascular resistance may produce cardiac symptoms which can lead to heart failure due to the arteriovenous shunt [19]. Such patients virtually face death in the absence of hemodialysis therapy, as a renal transplant is not readily available especially requiring emergency hemodialysis. CVC is effective but related to high infection complications impacting the image, comfort and even life of the patients. The KDOQI clinical practice guideline encouraged the selection of appropriate vascular access according to patient's ESKD Life-Plan [4] DAP is sure to be a good choice in a certain situation. However, DAP was limited due to complications such as hemorrhage, infection, vascular insufficiency, ischemia, thrombosis, embolization, and neuronal or adjacent structure injury [20]. Therefore, we must evaluate necessity and feasibility of DAP for patients undergoing hemodialysis.
In this study, 24 cases (63.2%) of DAP were on the radial artery. Radial artery, being easily accessible because of its superficial location, is one of the most preferred sites for DAP and has a low rate of procedural complications [9]. Radial artery puncture is a relatively safe procedure with an incidence of permanent ischemic complications of 0.09% [21]. Apart from cannulation on peripheral autologous arteries, 6 cases (15.8%) were punctured on anastomotic sites of abandoned fistula, which is so full and superficial as to puncture easily. It can be seen that choosing the correct cannulation site is particularly important to reduce complications. In addition, the puncture technique of nurse is vital to the success of DAP. In this survey, all DAP procedures were conducted by senior nurses. As reported, improving the puncture technique of nursing staff and using Doppler ultrasound guided puncture technique can improve the success rate of puncture, avoid injury of blood vessels, and prevent complications such as aneurysm, hematoma and massive bleeding [22]. The time-to-hemostasis compression after needle withdrawal was 0.5~1 hour among 16(42.1%) patients, Which was slightly longer than AVF cannulation. The methods of hemostasis depend on the different puncture sites. The brachial artery is deeper compared to radial artery, so the time of manual compression should be longer. Lower extremity with DAP should avoid walking before hemostasis. Accurate compressing point and suitable time to hemostasis could effectively reduce the occurrence of hematoma, hemorrhage and pseudoaneurysm. A vascular closure device set onto the skin and punctured by dialysis needle prevents bleeding from the punctured vessels, making hand compression unnecessary [23].
When it comes to the pain of cannulation, 29 (76.3%) patients self-reported mild pain during cannulation (NRS: 0~3 scores), indicating that most patients can stand the pain caused by DAP. The feeling of pain might adversely affect patient compliance with dialysis and quality of life. For the patients with pain intolerance, injection of local anesthetic and music therapy could decrease the pain of DAP [24].
As for the complications of DAP, aneurysm or pseudoaneurysm was reported in 16(42.1%) patients, which was one of the most common complications of DAP [25]. A study involving 28 patients was reported that,1 patient suffer from an infected pseudoaneurysm formation associated with DAP and 2 patients required an aneurysmectomy during 3 years [11]. Another study was reported that patients with hypertension, atrial fibrillation, or chronic kidney disease were more likely to develop a pseudoaneurysm than those without these conditions [26]. Therefore, when facing with patients prone to develop pseudoaneurysm, nurses should be more cautious and find ways to free the patients from pseudoaneurysm. Thrombin and external compression may be effective in treating upper extremity pseudoaneurysms [27]. Another complication more often reported was infiltration 12(31.6%) in this study. Whether in arteriovenous access cannulation or DAP, infiltration is a very common complication [28]. Missed cannulation was a vital reason for infiltration [29]. Before cannulation, the risk of missed cannulation could be minimized by fully evaluating the characteristics of the patient and the qualified nurses [29]. Ultrasound-guided cannulation and choosing appropriate plastic cannulae could decrease complications such as needle injuries caused by needle displacement due to arterial pulsation and restlessness of patients [4].
The results of this study show that DAP can provide average blood pump speed of 224.21±26.57ml/min, which was similar to studies on superficial brachial artery [11], higher than direct vena puncturing on cephalic vein as the inflow to dialyzer with a blood roller pump at a low rate of 120 to150ml/min [30], Moreover, the results of this study show that DAP was comparable to dialysis adequacy of other VA types. And compared with patients using CVC, there seems to be higher dialysis adequacy. It may be that when the VA is CVC, repeated circulation occurs and the inadequacy of dialysis happens for the relatively close distance between the inflow and outflow holes of the catheter [31], Therefore, DAP can achieve the required prescribed blood pump flow and adequacy of hemodialysis.
Limitations
This research has inherent shortcomings in cross-sectional research. First, the patency of DAP was not included in this study. Second, the effect of DAP is affected by the nurse's puncture technique. Third, the key of successful cannulation of DAP depends on the patients themselves naturally superficial artery, which may be the selection bias we could not avoid. In addition, DAP are limitted with the complications of aneurysm or pseudoaneurysm. We suggest improving the puncture technique and the safety of DAP with Color Doppler ultrasound or other advanced equipment and patients education rather than abandoning the direct arterial puncture technique that may paly an important role in saving patients under emergency conditions.
