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Percutaneous transluminal angioplasty (PTA) is an effective treatment for autogenous arteriovenous hemodialysis access (AAVA) stenosis; however, it causes pain in most cases. Therefore, safe and effective anesthesia for PTA is required.
We introduced a method of ultrasound-guided cradle-like infiltration anesthesia (UCIA) to administer analgesia during PTA. Using ultrasound guidance, 1% lidocaine was injected into the bilateral and inferior perivascular spaces of the stenosis to form a cradle-like region. In this study, 100 consecutive patients were divided into two groups, and the analgesic effect of UCIA was evaluated using a numerical rating scale with non-ultrasound-guided infiltration anesthesia as a control. Meanwhile, we compared the effect of PTA between the two groups with the postoperative internal diameter of the stenosis.
The numerical rating scale score was 4.6 ± 1.9 and 2.0 ± 1.6 (P < 0.001) in UCIA group and non-ultrasound-guided infiltration anesthesia group, respectively. The postoperative internal diameter of stenosis was 3.9 ± 0.6 mm and 4.1 ± 0.7 mm (P = 0.113); the postoperative AAVA flow volume was 627 ± 176 mL/min and 644 ± 145 mL/min (P = 0.600).
This study preliminarily showed that UCIA is effective and safe for the analgesia of AAVA PTA.
Functional vascular access is a prerequisite for hemodialysis in patients with end-stage renal disease (ESRD). The 2019 Kidney Disease Outcomes Quality Initiative (KDOQI) clinical practice guidelines for vascular access consider it reasonable to have autogenous arteriovenous hemodialysis access (AAVA) or arteriovenous graft in a patient requiring hemodialysis for their ESRD Life-Plan and overall goals of care.
However, vascular stenosis is one of the most common complications of AAVA, which not only reduces the adequacy of hemodialysis due to reduced blood pump flow rate or increased dialysis recirculation rate, but also results in thrombosis in severe cases.
Percutaneous transluminal angioplasty (PTA) is an effective approach for dealing with AAVA stenosis and is recommended as the primary treatment according to the 2019 KDOQI clinical practice guidelines.
PTA therapy could dilate the stenosed vessel effectively; however, causes obvious pain over the affected area in many cases. Balloon dilation stimulates the reticular plexus on the vascular wall, resulting in the generation of obvious pain. Thus, analgesia should be implemented during PTA for AAVA stenosis.
Approaches to anesthesia for vascular access procedures generally include general anesthesia (GA), intravenous moderate conscious sedation (IVCS), locoregional anesthesia (LRA), and local infiltrative anesthesia (LIA). Patients with ESRD are generally associated with multiple underlying diseases and complications, which increase the risk of GA or IVCS.
LIA is a simple and effective approach to analgesia with rare complications. The anesthetic solution is injected into the perivascular space to block the afference of the pain signal from the perivascular nerves to the central nervous system, which might theoretically work in PTA analgesia. Accurate injection of the analgesic into the appropriate area is the key to LIA, and the use of ultrasound guidance might be a good alternative. We introduced a method of ultrasound-guided cradle-like infiltrative anesthesia (UCIA) by injecting the analgesic into the bilateral and inferior perivascular spaces of the stenosis to form a cradle-like nerve block region. In this study, the analgesic effect of UCIA in AAVA PTA was evaluated using non-ultrasound-guided infiltrative anesthesia (NUIA) as a control.
MATERIALS AND METHODS
A total of 100 consecutive patients who underwent ultrasound-guided PTA for the treatment of AAVA stenosis in Sir Run Run Shaw Hospital (Hangzhou, China) from November 2016 to April 2017 were included in this single-center, prospective, controlled study. The study protocol adhered to the Declaration of Helsinki and was approved by the ethics committee of the hospital. Informed consent was obtained from all the patients participating in the study.
Patients aged 18–70 years who were conscious and able to participate in a pain assessment, with a forearm AAVA actively being used for dialysis that was greater than 3 months old, with evidence of single stenosis of AAVA that did not exceed 2 cm, agreed to undergo ultrasound-guided PTA were included. Stenosis was defined with reference to the 2006 KDOQI clinical practice guidelines and recommendations as the internal diameter (ID) of the vessel more than 50% smaller than that of the adjacent normal vessel, accompanied by decreased blood pump flow rate in hemodialysis, increased dialysis venous pressure, or increased dialysis recirculation rate.
Patients who had pain in their arm for other reasons, an unstable condition, anastomotic stenosis, arterial stenosis, central venous stenosis, AAVA infection or thrombosis, or allergy to lidocaine were excluded.
We generated 100 random numbers using the SPSS 13 statistical software package (IBM, USA) for the 100 patients. Patients were then listed and grouped by random numbers (patients with the top 50 larger random numbers were classified into group A and others to group B). NUIA and UCIA were administered to patients in groups A and B, respectively. The grouping information was preserved by a specific researcher, blinded to the patients consistently, and to operator until the operation began. Demographic data, PTA-related data, pain assessment scores, and complications were recorded for all patients. PTA-related data included PTA balloon diameter and pressure, the postoperative ID of stenosis, postoperative AAVA flow volume (FV), improvement of AAVA FV, and anatomic and clinical success rate. The pain was assessed using the numerical rating scale (NRS),
which used a 0–10 system to assess the degree of pain: 0 = no pain, 1–3 = mild pain, 4–6 = moderate pain, 7–9 = severe pain, and 10 = the most severe pain.
All procedures were performed by a nephrologist who was well trained in vascular ultrasound and PTA techniques and experienced in ultrasound-guided PTA for the treatment of AAVA stenosis.
All procedures were performed in the operating room, and the patients were monitored for electrocardiograms, oxygen saturation, and blood pressure. Prearranged plans for the adverse reactions of the local anesthetic were well prepared. The instruments used in this study included a duplex ultrasonography system (Vivid I, GE, Boston, USA) with a high-frequency linear-array transducer (9–12 MHz), and 5 mL syringes with 23–gauge needles.
Preoperative ultrasound examination was performed to measure the ID and length of the stenosis, the ID of the adjacent normal vessel, and the FV of the AAVA.
Before PTA procedures, all patients were instructed to learn to assess the pain using the NRS scores, and it was assured that the preoperative NRS scores at the limb of the AAVA were 0.
The PTA procedure consisted of the following steps:
After local anesthesia using 1% lidocaine in the puncture point, the AAVA vein was cannulated toward the stenosis under the guidance of ultra sound. A 5-French introducer sheath (Terumo, Tokyo, JP) was inserted, and 2,000 units of heparin were injected through the sheath.
A 0.035-in hydrophilic guidewire (HiWire, Cook, USA) was inserted to ensure that the head of the guide wire passed through the stenosis under ultrasound guidance.
NUIA and UCIA were applied to patients in groups A and B, respectively. Five milliliters of 1% lidocaine were used as the local anesthetic in both groups.
The first PTA was performed after the LIA. The diameter of the PTA balloon catheter (Armada, Abbott, USA) was determined to be 10% larger than that of the adjacent normal vessel. Under ultrasound monitoring, the PTA balloon catheter was placed over the guidewire, and the balloon was placed across the stenosis. The balloon was inflated by a pump until the stenosis was completely dilated, marked by the disappearance of the dent on the balloon. The complete dilating pressure was maintained for 30 sec and then gradually reduced to withdraw the balloon. The dilating pressure was not lower than the nominal pressure of the PTA balloon catheter but did not exceed the rated burst pressure. If the initial PTA balloon catheter could not dilate the stenosis successfully, an ultra-high pressure PTA balloon catheter (Conquest, BD, USA) of identical ID and length was used as an alternative.
The NRS scores for the first PTA were assessed and recorded. Pain assessment before and during the operation was administered by a specific assessor, who was unaware of the grouping, present but not participating in the operation. The operator would remind the patient and assessor before lidocaine was injected, or the balloon was inflated. The pain assessment was conducted just after reducing the pressure of the balloon to ensure that the pain assessment was for angioplasty only.
To maintain the balloon at the same place, the stenosis dilation procedure was repeated once with the same dilating pressure.
After PTA, the effects and complications were assessed by physical examination and ultrasonography. The ID of the stenosis and the FV of the AAVA were measured using ultrasound examination.
Removal of the sheath and hemostasis.
The anesthesia procedures of both groups consisted of the following steps.
Group A: LIA was performed on both sides of the stenosis without ultrasound guidance. The needle was inserted parallel and close to the vessel with the injection of 1% lidocaine (2.5 mL) on each side (Fig. 1). Injection of lidocaine into the vessel was avoided by withdrawing the plunger of the syringe to ensure that there was no back blood. After NUIA, the injection site was gently massaged to facilitate the distribution of the analgesic.
Group B: The ultrasound probe was placed at the midpoint of the stenosis to scan the vessel in the transverse section (Fig. 2), and the needle was then inserted under ultrasound guidance. In the ultrasound image, the needle could be identified by the banded hyperechoic structure. After the needle tip entered the subcutaneous site, a small amount of 1% lidocaine was injected to relieve pain at the puncture site. Then, the needle was advanced under ultrasound guidance until the tip approached one side of the stenosis. After injecting lidocaine, a hypoechoic area could be detected by ultrasound (Fig. 3A), indicating the successful infiltration of the anesthetic. Subsequently, the direction of the needle was changed to the inferior of the stenosis, and lidocaine was injected in the same manner (Fig. 3B). The needle tip was then passed under the stenosis to reach the contralateral side and continued with the anesthetic injection (Fig. 3C). As with UCIA, the plunger of the syringe was withdrawn before each injection to check whether the needle tip was inserted into the vessel. After LIA with a total of 5 mL 1% lidocaine, a hypoechoic area of the anesthetic was displayed on the ultrasound image, which formed a cradle-like area that wrapped the stenosis from the bilateral and inferior sides (Fig. 3D). The hypoechoic area under the stenosis can also be displayed on the images of the longitudinal scan (Fig. 4). The injection site was gently massaged to evenly distribute the anesthetic.
Study Outcomes and Statistical Analysis
Enumeration data and measurement data were analyzed using the chi-square test and t-test of two independent samples, respectively. Values of P < 0.05 were as considered statistically significant.
The demographic data and the the preoperative parameters of the patients in the two groups were recorded and compared, including age, sex, hypertension, diabetes, ID and length of a stenosis, and the FV of AAVA.
The diameter of the PTA balloon catheter and the balloon pressure of the first PTA were recorded. The ID of the stenosis and the FV of the AAVA after PTA were recorded and compared between the two groups. The anatomic and clinical success rates of PTA were also compared between the two groups. A residual stenosis rate not exceeding 30% was regarded as an anatomic success, and the resumption of at least one successful dialysis session using the treated AAVA was defined as clinical success.
The NRS scores of the first PTA were compared between the two groups.
Adverse events were also recorded and compared, including the side effects of the anesthetic and complications of PTA (vascular rupture and thrombosis).
All analyses were performed using the SPSS 13 Statistical Software Package (IBM,USA).
The demographic data and preoperative parameters of the two groups are listed in Table I. Analyses of the data revealed no significant differences between the two groups.
Table IDemographic data and preoperative parameters
The preoperative AAVA FV in group A was greater than that in group B, and the improvement of FV in group B was greater than that in group A; no other significant differences were found between the two groups, including demographic data, preoperative parameters, operative parameters, and postoperative parameters. The mean NRS score in group B was significantly lower than that in group A. No side effects of the anesthetic or complications of PTA occurred in either group.
PTA therapy for AAVA stenosis is often associated with severe pain, which not only causes great mental distress to the patients but also interferes with their therapeutic compliance. Additionally, severe pain may cause unfavorable neurohumoral responses, such as vascular spasm, hypertension, tachycardia, or even cardiovascular diseases (CVD), of which patients with ESRD are at high risk.
GA is technically complicated and can only be performed by experienced anesthetists. Meanwhile, patients with ESRD are generally associated with underlying diseases and complications such as CVD, neuropathy, and chronic obstructive pulmonary disease, all of which increase the risk of GA.
Although IVCS is simpler than GA, the depth of analgesia is also restricted by the underlying diseases and complications in patients with ESRD. Low ventilation and hypoxia are the major risks of IVCS that increase mortality, which is even higher than that of GA.
LRA has sympatholytic and venodilatory effects and cardiovascular stability and has become a preferred choice for vascular access surgery. However, the implementation of LRA requires an experienced anesthetist and is relatively complicated for the PTA procedure. Moreover, LRA causes several hours of limb paralysis after the operation. Thus, a safe, minimally invasive, and simple approach for PTA is urgently needed. LIA is safer than GA and IVCS and simpler than LRA and might be a favorable alternative for PTA. However, clinical studies on LIA in PTA of AAVA are rare. A clinical study with a small sample size preliminarily demonstrated that tumescent anesthesia (TA) had an analgesic effect on the PTA of AAVA.
TA is advantageous owing to the low concentration of the local anesthetic; however, may lead to local edema and tissue dissection, as it requires a relatively large volume of anesthetic solution. Haines et al. reported that the mean volume of the anesthetic solution needed for PTA procedures was 14.5 Ml.
However, the large volume of the anesthetic solution may result in compression of the stenosed vessel, which may increase the risk of thrombosis of AAVA. Additionally, injection of such a large volume of anesthetic would induce obvious tissue dissection and cause obvious pain. Thus, we attempted to reduce the required volume of the anesthetic by increasing the concentration to obtain a similar analgesic effect.
UCIA aims to inject the anesthetic accurately into a certain area around the stenosed vessel under ultrasound guidance. The anesthetic was injected to both sides and the inferior aspect of the stenosis to form a cradle-like area that wrapped the stenosed vessel inside. Consequently, most algesia impulsions from the stenosed vessel may be inhibited from being sent out. Ultrasound can display the movement of the needle and ensure accurate injection of the anesthetic close to the stenosis, which makes UCIA superior to NUIA. The advantage of the transverse scan is that the needle and vessel can be shown in the same image, which makes the anesthetic operation visual and simple, even allowing the needle to pass through the inferior aspect of the vessel and reach the contralateral side. In some cases, distinguishing the needle from the tissue is challenging as the strength of the echo is similar. To deal with this problem, a small amount of the anesthetic solution was injected to form an aqueous hypoechoic area so that a stronger echo of the needle tip can be identified more easily. Another advantage of UCIA is that only a single puncture point is needed, unlike NUIA, which requires bilateral puncture points. Moreover, we performed anesthesia after the guidewire passed through the stenosis; otherwise, the compression of the anesthetic on the stenosis would increase the challenge in guidewire passing. Additionally, the early passage of the guidewire before anesthesia could facilitate the placement and dilation of the PTA balloon, which could shorten the duration of the compression on the stenosis and decrease the risk of thrombosis.
According to the results, although the preopera tive stenosis ID and mean diameter of the balloons used in the two groups were similar, the NRS score in the UCIA group was significantly lower than that in the NUIA group, indicating that the analgesic effect of UCIA is better than that of NUIA. No significant differences were found in the mean postoperative ID of stenosis, anatomic success rate or clinical success rate between the two groups, while the improvement of FV in group B was greater than that in group A, indicating that UCIA does not produce negative effects on the therapeutic efficacy of PTA as compared with NUIA.
It has been found that 70% of lidocaine is metabolized in the liver by N-dealkylation and hydrolysis,
suggesting that lidocaine should still be used with caution in patients with ESRD. For regional nerve blocks in ESRD adults, a single dose of lidocaine should not exceed 4.5 mg/kg, and the daily dose should not exceed 300 mg.
The incidence rate of lidocaine toxic reaction is 0.02–0.8% in a dose- and concentration-dependent manner and the main adverse effects of lidocaine include neurotoxicity, cardiovascular toxicity, and hypersensitivity.
Other than hypersensitivity, most adverse effects are related to the dose and entry of lidocaine into the circulation. In addition to withdrawing the plunger of the syringe to check the back blood, ultrasound guidance can also help avoid the entry of lidocaine into the blood.
Nevertheless, the conclusion of the present study can be further completed. The superiority of the UCIA should be further verified in multicenter randomized controlled trials. In addition, further studies are required to determine whether a lower concentration or smaller volume of lidocaine could achieve a similar analgesic effect. A lower dosage indicates a lower risk of anesthetic toxicity, which is particularly important for cases with multiple or long stenoses.
This single-center study preliminarily showed that UCIA is a safe, simple, and minimally invasive approach for the analgesia of AAVA PTA, which produces minimal pain for patients undergo PTA procedures.
CONFLICT OF INTEREST
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
This study was supported by the Natural Science Foundation of Zhejiang Province (Grant No. LSY19H050001 ).
KDOQI clinical practice guideline for vascular access: 2019 Update.