Right Heart Catheterization via Dialysis Arteriovenous Shunts in End-Stage Renal Disease Patients

Abstract: Objectives. Right heart catheterization is an important diagnostic tool but carries risks of adverse events. Little is known about the feasibility and safety of using dialysis arteriovenous (AV) shunts. We aim to evaluate the feasibility and safety of using dialysis AV shunts for access in right heart catheterization. Methods. Hemodialysis patients who required right heart catheterization were prospectively enrolled. A 7 Fr sheath was inserted and a balloon-tipped pulmonary artery catheter was advanced for right heart catheterization. Patients were followed for 1 month, and technical success, procedure details, and complications were recorded. Results. Thirteen patients received right heart catheterization via AV shunts. Three patients were evaluated for heart failure, and 10 were examined for pulmonary hypertension. Median patient age was 69 years (interquartile range [IQR], 58-77 years), and median shunt age was 50 months (IQR, 32-75 months). Five shunts were located in the upper arm, 2 were in the right arm, and 5 were native fistulas. All AV shunt punctures were successful on the first attempt. All right heart catheterizations were completed via AV shunts, and the technical success rate was 100%. Median fluoroscopy time was 6.9 minutes. No venous access complications or right heart catheterization–related complications occurred immediately after the procedure or during the 1-month follow-up period. Conclusions. AV dialysis shunts can be used for venous access for right heart catheterization with acceptable feasibility and patient tolerability. Further randomized studies are needed to confirm the benefits of this approach compared with other approaches. 

J INVASIVE CARDIOL 2016;28(12):480-484. Epub 2016 September 15.

Key words: dialysis access, end-stage renal disease, right heart catheterization

Right heart catheterization (RHC) is a useful tool in the diagnosis of congenital and acquired right heart diseases because of its ability to accurately measure cardiac events. Direct injection of medications, pressure measurement, and angiographic visualization can be carried out using this technique. In addition, RHC is used for the diagnosis of pulmonary hypertension, evaluation of potential reversibility, and guidance for therapeutic interventions. 

Although RHC is usually considered safer than left-side catheterization, the procedure can lead to serious and sometimes life-threatening complications, including hematoma, vagal reaction, and pneumothorax. Traditionally, femoral, internal jugular, subclavian, and brachial veins have been used for venous access during RHC. In patients with end-stage renal disease (ESRD) receiving maintenance hemodialysis, arteriovenous (AV) shunts, including synthetic grafts and native fistulas, are usually created to mitigate the need for repeated punctures. Most AV shunts are located in the upper limb, are enlarged in size, and are superficial with thrills to facilitate identification. Theoretically, AV shunts may provide suitable venous access for RHC in hemodialysis patients, with the possible advantages of easy puncture, simple hemostasis, and patient comfort. Thus, we carried out this prospective study to assess the feasibility, success, and safety of an AV shunt approach during the performance of RHC in hemodialysis patients.  

Methods

Patients. From January 2012 through December 2014, we consecutively invited hemodialysis patients in whom RHC was indicated to participate in this study. The inclusion criteria were: (1) presence of functional AV shunts – either native fistulas or synthetic grafts – created in the upper limb and present for at least 3 months; and (2) administration of regular maintenance hemodialysis for at least 3 months. The exclusion criteria were: (1) history of totally occluded subclavian vein at the ipsilateral side of the AV shunts; or (2) clinical evidence of AV shunt dysfunction or infection. The study protocol was approved by our hospital’s institutional review board. All participants provided written informed consent for both the study and RHC. 

Preprocedural preparation. All RHC procedures were performed on an outpatient basis. Before the procedure, the patient’s history and a physical examination of the AV shunt were obtained in the catheterization laboratory, including shunt flow and static venous pressure during dialysis, history of central vein stenosis, and difficulty in cannulation. Food or drinks were not allowed 4 hours before the procedure. Antiplatelet and anticoagulant agents were continued before the catheterization if already in use. Body temperature, heart rate, blood pressure, and oxygen saturation by pulse oximeter were checked, and history of hospitalization within 1 month was obtained. The procedure was canceled if fever, hypotension, respiratory distress, or clinical evidence of AV shunt infection were present. In all patients, standard aseptic techniques were used, but prophylactic antibiotics were not used. A continuous electrocardiogram monitor was set up as standard. 

Puncture. Two interventional cardiologists performed the procedures. Ultrasound was not used for guidance of the puncture. The puncture site was chosen at the usual cannulation site for hemodialysis at the venous limb of the AV shunts. If the usual cannulation site was distal to the elbow, the puncture location was chosen as proximal as possible to another part of the shunt. After local anesthesia with lidocaine (2%, 2 mL), a puncture was made with a 30 mm, 20 gauge sheathed needle to AV shunt toward the venous limb and then slowly withdrawn to allow blood purge from the central hub of the needle. After the needle was removed, a 45 cm, 0.025˝ hydrophilic guidewire was inserted through the bleeding hub. The 20 gauge soft sheath was removed, and a 7 Fr short sheath (5 cm; Terumo) was introduced into the AV shunt through the guidewire. The guidewire was then removed, leaving the sheath in place, and normal saline was flushed into the sheath. The sheath was then fixed in place. Figure 1 shows the process to establish vascular access on a synthetic AV graft. 

Right heart catheterization. A 7 Fr 110 cm-length Safety Wedge pulmonary artery catheter (Biosensors International) was used for RHC. The catheter was advanced into the middle portion of the right atrium with gentle rotation and step-wise advancement under fluoroscopic guidance. If the catheter did not traverse the veins of the shoulder with ease, the balloon was inflated with 0.5 mL of air, and the catheter was withdrawn slightly before re-advancement. Road-mapping after puffs of contrast injection could be used to facilitate steering of the catheter. For sharp venous angulation, the advancement of the catheter could also be facilitated by a 0.025˝ wire or partial inflation–deflation of the tip balloon. If the presence of significant stenosis caused difficulty in advancing the catheter, a standard angioplasty procedure was performed before the pulmonary catheter was advanced.^1-3 In the right atrium, the balloon was inflated to a total volume of 0.8 mL, and the catheter was floated to the right ventricle and the pulmonary artery under pressure and with electrocardiographic monitoring. The balloon then proceeded downstream until pressure resembling the pulmonary artery wedge pressure was obtained. When appropriate wedge pressure was acquired, the balloon was deflated and the catheter was then withdrawn. Serial measurements of pressure and oxygen saturation at the pulmonary artery, right ventricle, and right atrium were performed, and cardiac output was determined by the thermodilution method with cold saline. The pulmonary artery catheter was then removed. Figure 2 shows the process of RHC on a patient with a native AV fistula. 

Postcatheterization care. After RHC, the sheath was removed and hemostasis was achieved by manual compression at the puncture site in the recovery area of the catheterization laboratory. Pressure was applied by digits to stop oozing at the puncture site while the thrills of the shunts were still palpable during compression. After hemostasis, an occlusive bandage was placed over the puncture wound. Patients were free to mobilize their arms. After 30 minutes of observation, the patients left the catheterization laboratory after a final examination of vital signs and the puncture wound. Patient condition and the status of their AV shunt were followed at outpatient clinics 1 week after discharge and again 1 month later by review of medical records, dialysis records, and telephone contact with their physicians and dialysis centers. 

Definitions. Access time was defined as the interval between local anesthetic injection and sheath placement in the AV shunts. Procedure time was defined as the interval between initial catheter insertion and completion of the right heart study. Technical success was defined as successful acquisition of the hemodynamic data, including the wedge pressure. Complication was classified as related to venous access or to RHC.

Statistical analysis. Results are reported as mean ± standard deviations for normally distributed continuous variables and as median (interquartile range [IQR]) for non–normally distributed variables. Categorical variables are reported as percentages. 

Results 

Patient and access characteristics. From January 2012 to December 2014, a total of 13 consecutive patients received RHC via AV shunt. The demographics of study participants are summarized in Table 1. The indications for RHC were to diagnose pulmonary hypertension in 10 patients and to evaluate heart failure in 3 patients. The mean age of study participants was 63 years, and 5 were male (38%). The median age of the patients’ AV shunts was 50 months (IQR, 32-75 months), and their median duration of dialysis was 68 months (IQR, 38-122 months). Five AV shunts were native fistulas, and the others were synthetic grafts. Two AV shunts were located in the right arm (15%) and 5 were located in the upper arm (38%). 

Procedure time and success rate (Table 2). All punctures to AV shunts were successful on the first attempt. No ultrasound guidance was needed for preprocedural screening or to facilitate the puncture. All patients tolerated the puncture with local anesthetic alone. The median puncture time was 48 seconds (IQR, 39-62 seconds). One patient had a significant cephalic vein stenosis that hampered the pulmonary catheter advancement. Balloon angioplasty was done, and RHC was completed afterward. In 1 patient, the operator experienced difficulty in crossing the cephalic arch by pulmonary artery catheter, but the procedure was facilitated by a 0.025˝ hydrophilic guidewire. Pulmonary artery catheters were successfully floated to the pulmonary artery wedge area in all patients. Complete measurements of hemodynamic profiles were made in all patients without the need to obtain other vascular access, and the technical success rate was 100%. All study participants tolerated the puncture well, without the need for additional sedation or analgesics. 

Median procedure time was 19 minutes (IQR, 14-23 minutes) and fluoroscopy time was 6.9 minutes (IQR, 4.3-9.9 minutes). All catheters were floated to the wedge successfully. Median mean pulmonary artery pressure was 27 mm Hg (IQR, 14-52 mm Hg) and the median pulmonary capillary wedge pressure was 16.5 mm Hg (IQR, 10-32 mm Hg). Hemodynamic studies were completed in all cases. The median cardiac output was 3.8 L/min (IQR, 2.1-6.7 L/min) and pulmonary vascular resistance was 5.3 Wood units (IQR, 0.6-80 Wood units). Hemostasis was successfully achieved by manual compression in all patients, and all patients left the catheterization laboratory within 1 hour after the procedures and were discharged. 

Complications. Immediately after the procedure, no venous access complications, including puncture-site hematoma, fistula, or pseudoaneurysm, were noted. There was no inadvertent arterial puncture. No vascular rupture, dissection, or occlusion was found during or after the procedure. No vagal reaction with bradycardia or hypotension was noted after AV shunt puncture or RHC. There were no pneumothoraxes, pulmonary hemorrhages, or pulmonary embolisms reported at 1 month after the procedure. Transient atrial or ventricular premature complexes were common during the procedures when the catheter entered into the right atrium or ventricle, but no sustained arrhythmia, bundle-branch block, or complete heart block was found. Sedative agents were not given during the procedure; therefore, no adverse events were related to sedation. At the 1-week and 1-month follow-ups, no patient had experienced AV shunt complications such as hematoma, fistula, aneurysm, or thrombotic or infection events. There were no deaths within 1 month after the procedure. 

Discussion

In this prospective study, we described our single-center experience using dialysis AV shunts for RHC. According to the data we provided, dialysis AV shunts may be a feasible means of access for RHC and may have the advantages of time savings for access, rare occurrences of complications, and ease of postcatheterization care. 

RHC is an important diagnostic tool for both cardiac and pulmonary vascular diseases. For the diagnosis of pulmonary hypertension, it is the gold standard for diagnosis and facilitates decisions regarding therapeutic interventions. In our cohort of ESRD patients, a diagnosis of pulmonary hypertension was the most common indication for RHC. It is increasingly recognized that the prevalence of pulmonary hypertension is much higher in uremic patients than in the general population,⁴ and the condition is accompanied by a poor prognosis.⁵ Although transthoracic echocardiography is a convenient screening tool, a confirmative diagnosis still requires RHC to differentiate between precapillary and postcapillary pulmonary hypertension.^6,7

Although arterial puncture was not needed, RHC is still associated with a substantial risk of adverse events, including mechanical issues, thrombosis, infection, and cardiac events. In a large 5-year multicenter registry of 7218 RHCs performed following a diagnosis of pulmonary hypertension, RHC was associated with 29 vascular access-site complications and hemodynamic complications. Venous access complications, including hematoma, vagal reaction, pneumothorax, and AV fistulas, are the most common adverse events related to RHC.⁸ In studies of central venous catheter placement, complication rates were 19.8% for the femoral vein approach, 4.5% for the subclavian vein approach, and 1.7% for approach via the internal jugular veins.^9,10 In ESRD patients, the complication rate may be much higher for several reasons. First, femoral, jugular, or subclavian vein stenosis is more frequent in ESRD patients because of their history of temporary catheter insertion. Second, ESRD patients are at risk of bleeding or thrombosis due to hematologic or metabolic disarrangement secondary to uremia. Although no specific complication rate for RHC in ESRD patients is available, ESRD is a well-known risk factor for vascular access complications in patients who receive left heart catheterization.^11-13

The route for advancing the pulmonary artery catheter to the right heart is longer than for the femoral or jugular vein approach. The first human catheterization by Dr Forssmann in the 1920s was performed via the left cubital vein approach. The introduction of the Swan–Ganz balloon flotation catheter in 1970 for RHC used the antecubital vein as well. Actually, the route for catheter advancement from the dialysis AV shunt to the right heart was the same as for antecubital vein approach. In our study, the pulmonary artery catheter could be easily advanced across the shoulder veins. Although a variety of techniques could facilitate the use of the pulmonary artery catheter, they were rarely needed in our study. The creation of an AV shunt made the veins in the upper arm larger in size and increased the flow, which may facilitate the advancement of pulmonary artery catheters. 

There are several advantages of using dialysis AV shunts for RHC. First, the AV shunts are easily visible with palpable thrills that facilitate localization. In contrast, the femoral and internal jugular veins are relatively deep and are more challenging to identify, and anomalies or stenosis may be present, which can create difficulties related to punctures or wiring. Ultrasound sometimes may be needed to facilitate a safe puncture of the femoral or internal jugular veins. In our study, the punctures of AV shunts were always successful on the first attempt without the need for ultrasound guidance.^14,15 Inadvertent arterial punctures during femoral or jugular vein approach may complicate the procedure or even cause vascular complications. In contrast, the superficial location of AV shunts mitigates the risk of arterial puncture. In ESRD patients, bleeding or thrombotic tendencies are present in a substantial portion of patients.^16,17 Use of a dialysis AV shunt is easy for both puncture and to reduce bleeding. Hence, this approach greatly reduces the risk of venous access-site complications. 

After sheath removal, hemostasis was achieved by gentle digital pressure or use of an elastic bandage for hemostasis after hemodialysis. Hemostasis was also achieved with patients in the sitting position, without the need for postprocedural recumbency to avoid disruption at the puncture site. This may be especially helpful for patients with heart or lung disease and hip or back pain. Monitoring for puncture-site bleeding was easy and could be undertaken by the patient or a family member. Therefore, the dialysis AV shunt approach reduced not only the puncture-site complications but also allowed immediate mobilization after the procedure and shortened the hospital observation period. Therefore, RHC could be scheduled as an outpatient procedure, which increased the patient’s comfort and satisfaction, reduced the workload of the nursing staff, and decreased medical costs. 

Some drawbacks of this approach should be addressed. The major concern for this approach is a risk of injury to AV shunt. Nonetheless, no dysfunction or thrombosis of AV shunt occurred in the 1-month follow-up period. Our study demonstrated the feasibility and safety of the AV shunt approach for temporary diagnostic use of RHC. The safety of prolonged catheterization for hemodynamic monitoring in the intensive care unit still needs to be investigated. Sometimes, resistance may be encountered when the catheter traverses shoulder veins. The passing of catheters could usually be facilitated by a test contrast, use of a guidewire, or partial inflation of the balloon. In the presence of significant stenosis in the outflow vein, balloon dilation was sometimes needed. Because of the variations in the length from the AV shunts to the wedge area, the working length of the pulmonary artery catheter may not be sufficient if venous access was initiated below the elbow. 

Study limitations. The main limitation of this study is the small sample size. Difference in the length from the access point to the pulmonary artery secondary to variation in body habitus may limit the generalizability of our findings. The operators in the present study were experienced in the intervention of AV shunts. The safety of this new technique in the hands of less experienced operators still needs to be investigated.  

Conclusion

The present study demonstrated that RHC via dialysis AV shunts appears to be feasible, with good patient tolerability. Our findings, however, need to be confirmed in future randomized trials with comparisons to other approaches. 

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From the ¹Cardiovascular Center, National Taiwan University Hospital, Hsinchu Branch, Taiwan; ²College of Medicine, National Taiwan University, Taipei, Taiwan; ³Department of Internal Medicine and Center for Critical Care Medicine, National Taiwan University Hospital Hsinchu Branch, Hsinchu, Taiwan; ⁴Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan; ⁵Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan; ⁶School of Medicine, National Yang-Ming University, Taipei, Taiwan; ⁷Institute of Biomedical Engineering, National Tsing-Hua University, Hsinchu, Taiwan.

Funding. This study was supported by grants from the National Taiwan University Hospital, Hsinchu Branch (DOH-99-HO-2022, 100-026-F, HCH101-12, HCH102-33, HCH103-067, HCH103-001, HCH104-011).  

Disclosure. The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

Manuscript submitted March 10, 2016, provisional acceptance given May 5, 2016, final version accepted May 23, 2016.

Address for correspondence: Chih-Cheng Wu, MD, Cardiovascular Center, National Taiwan University Hospital Hsinchu Branch, Taiwan, National Taiwan University, College of Medicine, Taiwan, No. 25, Lane 442, Sec. 1, Jingguo Rd, Hsinchu City 300, Taiwan. Email: chihchengwumd@gmail.com