Difficult cannulation of hemodialysis arteriovenous fistula - Role of imaging in access management (DICAF STUDY)

BACKGROUND

Difficulty in cannulation of arteriovenous fistula (AVF) can lead to inadequate dialysis, transient to permanent loss of access and increases dependency on bridging catheters. This study aimed to analyze the causes for difficult fistula cannulation, using various imaging modalities.

METHODOLOGY

This was a retrospective single-center observational study conducted between October 2017 and June 2018. Patients whose fistulae were difficult to cannulate were initially evaluated by physical examination followed by doppler ultrasonography or/and fistulogram as necessary. The patients were divided into two groups that is, primary difficult cannulation (within first three months of creation of fistula) or secondary difficult cannulation (after three months).

RESULTS

We encountered difficult cannulation in 43 patients. About 60% were primary difficult cannulations. Most common causes for difficulty in cannulation were cannulation zone (CZ) stenosis (23.3%), immature fistula (20.9%), outflow stenosis (18.6%), inflow stenosis (11.6%), anatomical abnormalities (11.6%), outflow plus CZ stenosis (9.3%) and inflow plus CZ stenosis (4.7%). Among patients with primary difficult cannulation, immature fistula (34.6%) was the most common cause, whereas CZ stenosis (47.1%) was the most common etiology for secondary difficult cannulation. Edema leading to difficult cannulation was found in 12 patients (27.9%), all of which was due to central vein stenosis. Cannulation resulted in hematoma, fistula thrombosis, failure of fistula and pseudoaneurysm in 83.7%, 27.9%, 16.3%, and 2.3% of cases respectively. Bridging temporary dialysis catheter placement was required in 67.4% patients. Ultrasound doppler had lower diagnostic value when compared to fistulogram (71.4% vs 93.9%, p = 0.014).

CONCLUSION

Difficulty in cannulating the arteriovenous fistula is a common problem in hemodialysis patients. We suggest that patients whose fistulae are difficult to cannulate should undergo early radiological evaluation to decrease catheter dependency and access failure.

Factors Predicting Difficult Biliary Cannulation during Endoscopic Retrograde Cholangiopancreatography for Common Bile Duct Stones

Background/Aims

Difficult biliary cannulation is an important risk factor for post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP). Therefore, this study aimed to identify the factors that predict difficult cannulation for common bile duct stones (CBDS) to reduce the risk for PEP.

Methods

This multicenter retrospective study included 1,406 consecutive patients with native papillae who underwent ERCP for CBDS. Factors predicting difficult cannulation for CBDS were identified using univariate and multivariate analyses.

Results

Univariate analysis showed that six factors significantly predicted difficult cannulation: ERCP performed by non-expert endoscopists, low-volume center, absence of acute cholangitis, normal serum bilirubin, intradiverticular papilla, and type of major duodenal papilla. Multivariate analysis identified ERCP performed by non-expert endoscopists (odds ratio [OR], 2.5; p<0.001), low-volume center (OR, 1.6; p<0.001), intradiverticular papilla (OR, 1.3; p=0.007), normal serum bilirubin (OR, 1.3; p=0.038), and absence of acute cholangitis (OR, 1.3; p=0.049) as factors significantly predicting difficult cannulation for CBDS.

Conclusions

Initial cannulation by an experienced endoscopist, early rescue cannulation, or early takeover by an experienced endoscopist should be considered when performing ERCP for CBDS in the presence of factors predicting difficult cannulation.

Impact of periampullary diverticulum on biliary cannulation and ERCP outcomes: a single-center experience

BACKGROUND

Periampullary diverticulum (PAD) is frequently come upon during endoscopic retrograde cholangiopancreatography (ERCP), especially in elderly patients. However, less is known about the role of PAD in biliary cannulation difficulty.

AIM

This study aims to investigate the association of PAD and difficult cannulation and evaluate the impact of different types of PAD on the cannulation success rate and adverse events.

METHODS

Prospectively collected data on a total of 636 patients who underwent endoscopic retrograde cholangiopancreatography (ERCP) were divided into two groups based on the presence or absence of PAD. Besides, the patients were classified based on the PAD types into three groups. The primary outcomes were cannulation success rate, cannulation time, and ERCP-related adverse events. Further, the difficult cannulation and presence of PAD were analyzed using logistic regression models.

RESULTS

Significant higher rates of biliary stones, cholangitis, and biliary pancreatitis were observed in the PAD group. Successful selective cannulation was achieved in 97.6% in the PAD group and 95.3% in the control group. The cannulation time was significantly longer in the presence of PAD. There was no significant difference in the rate of overall adverse events and post-ERCP pancreatic PEP. Multivariate analysis showed that type 1 PAD, biliary stones, and cholangitis were factors related to difficult cannulation.

CONCLUSION

The presence of PAD did not affect the duration or success of the ERCP procedure. However, it was associated with longer cannulation time and an increase in the cannulation difficulty, especially with PAD type 1. Clinical Trial Study Registration This study is approved by Nanjing Medical University and registered at ClinicalTrial.gov PRS with ID/NCT03771547/.

Endoscopic retrograde cholangiopancreatography in elderly patients: Difficult cannulation and adverse events

BACKGROUND

Endoscopic retrograde cholangiopancreatography (ERCP) is a valuable therapeutic technique for pancreatobiliary diseases, and its application in the elderly is no longer limited. However, a higher incidence of procedure difficulty and periprocedural adverse events might be expected in elderly patients due to the presence of other medical disorders and the poor general condition of this population.

AIM

To evaluate the incidence, causes, and management of difficult biliary cannulation during ERCP in elderly patients and the role of difficult cannulation as a risk factor for adverse events.

METHODS

A total of 614 patients who underwent ERCP during the study period were prospectively studied and divided into two groups based on their age. One hundred and forty-six patients were aged 80 years or older and 468 patients were aged less than 80 years. The primary outcome measurements were cannulation difficulty, cannulation success rate, ERCP procedure time, and related adverse events.

RESULTS

There was no difference in the incidence of difficult cannulation among the two groups (32.9% vs 34.4%, P = 0.765), as well as in the cannulation success rate (96.6% vs 96.8%, P = 0.54). The cannulation techniques were shown to be safe and efficient in achieving successful cannulation. Logistic regression analysis showed that patients aged 80 years or older were not associated with increased adverse events; however, difficult cannulation cases [adjusted odds ratio (AOR) = 3.478; 95% confidence interval (CI): 1.877-6.442; P < 0.001] and patients with Charlson Comorbidity Index ≥ 2 (AOR = 1.824; 95%CI: 0.993-3.349; P = 0.045) were more likely to develop adverse events. In contrast, other factors including age ≤ 65 (AOR = 3.460; 95%CI: 1.511-7.922; P = 0.003), female gender (AOR = 2.362; 95%CI=1.089-5.124; P = 0.030), difficult cannulation (AOR = 4.527; 95%CI: 2.078-9.860; P < 0.001), and patients with cholangitis (AOR = 3.261; 95%CI: 1.204-8.832; P = 0.020) were strongly associated with a higher rate of post-ERCP pancreatitis.

CONCLUSION

Advanced age has not been proved to be a risk factor for difficult cannulation, and secondary cannulation techniques can be safely and efficaciously utilized in this group. Patients with a Charlson Comorbidity Index ≥ 2 and difficult cannulation are associated with an increased overall adverse events rate, while age ≥ 80 years is not.

Clinical significance of different periampullary diverticulum classifications for endoscopic retrograde cholangiopancreatography cannulation

BACKGROUND

Different types of periampullary diverticulum (PAD) may differentially affect the success of endoscopic retrograde cholangiopancreatography (ERCP) cannulation, but the clinical significance of the two current PAD classifications for cannulation is limited.

AIM

To verify the clinical value of our newly proposed PAD classification.

METHODS

A new PAD classification (Li-Tanaka classification) was proposed at our center. All PAD patients with native papillae who underwent ERCP from January 2012 to December 2017 were classified according to three classification systems, and the effects of various types of PAD on ERCP cannulation were compared.

RESULTS

A total of 3564 patients with native papillae were enrolled, including 967 (27.13%) PAD patients and 2597 (72.87%) non-PAD patients. In the Li-Tanaka classification, type I PAD patients exhibited the highest difficult cannulation rate (23.1%, P = 0.01), and type II and IV patients had the highest cannulation success rates (99.4% in type II and 99.3% in type IV, P < 0.001). In a multivariable-adjusted logistic model, the overall successful cannulation rate in PAD patients was higher than that in non-PAD patients [odds ratio (OR) = 1.87, 95% confidence interval (CI): 1.04-3037, P = 0.037]. In addition, compared to the non-PAD group, the difficulty of cannulation in the type I PAD group according to the Li-Tanaka classification was greater (OR = 2.04, 95%CI: 1.13-3.68, P = 0.004), and the successful cannulation rate was lower (OR = 0.27, 95%CI: 0.11-0.66, P < 0.001), while it was higher in the type II PAD group (OR = 4.44, 95%CI: 1.61-12.29, P < 0.01).

CONCLUSION

Among the three PAD classifications, the Li-Tanaka classification has an obvious clinical advantage for ERCP cannulation, and it is helpful for evaluating potentially difficult and successful cannulation cases among different types of PAD patients.

Management of difficult or failed biliary access in initial ERCP: A review of current literature

Selective bile duct cannulation is the prerequisite for all endoscopic biliary therapeutic interventions, but this cannot always be achieved easily. Despite advances and new developments in endoscopic accessories, selective biliary access fails in 5%-15% of cases, even in expert high volume centers. Various techniques - such as double-guidewire induced cannulation, pre-cut papillotomy or transpancreatic sphincterotomy with or without placement of a pancreatic stent - have been used to improve cannulation success rates. Repeated and prolonged attempts at cannulation increase the risk of pancreatitis. Repeating the ERCP within a few days after initial failed pre-cut is a successful strategy and should be tried before contemplating more invasive, alternative interventions such as percutaneous-endoscopic or endoscopic ultrasound guided rendezvous procedure, percutaneous transhepatic or surgical intervention. However, standard guidelines or sequential protocol has not been existed up to now. In certain circumstances, there are unique clinical indications for which invasive, alternative interventions should be preferred. We present and discuss the methods that can be used in difficult or failed initial ERCP, therefore to provide practical advice for endoscopists, especially those who are inexperienced.

Management of difficult bile duct cannulation in ERCP

In Encoscopic Retrograde Cholangiopancreatography (ERCP), the main concern is to gain access into the bile duct while avoiding the pancreatic duct because of the risk of post-ERCP pancreatitis. Difficult cannulation is defined as a situation where the endoscopist, using his/her regularly used cannulation technique, fails within a certain time limit or after a certain number of unsuccessful attempts. Different methods have been developed to manage difficult cannulation. The most common solution is to perform a precut papillotomy either with a needle knife or with a sphincterotome with or without a guide wire. This review describes different methods to overcome cases of difficult cannulation. We will discuss the success rate and complication rates associated with different methods of reaching the biliary tract.