Maintenance of definitive vascular access (VA) for patients with end-stage renal disease can be a challenge, particularly in those who have been established on hemodialysis (HD) for many years. The optimal access route for patients on HD has long been thought to be an arteriovenous fistula (AVF), as high blood flow rates and improved clearance can be achieved, furthermore there are reduced risks of long-term complications and often financial benefits compared with other types of long-term VA (e.g., arteriovenous grafts and tunneled HD catheters [THCs]).
THCs are considered to be a less desirable form of long-term HD access because of the increased risk of complications and all-cause mortality, when compared with other forms of VA.
We present a case of a patient who presented with chest pain while dialysing through an AVF, after previously starting HD via a left internal jugular THC. Investigation demonstrated a mediastinal hematoma, hemopericardium, and hemothorax from a bleeding mediastinal collateral vessel. To our knowledge, there are no previous reports describing this presentation. It highlights the risks of THC use as well as the importance of, where possible, establishing optimal long-term access in the form of an AVF in all patients before commencing HD.
A 40-year-old woman with end-stage renal disease secondary to nephrotic syndrome of unknown cause presented via the emergency department with sudden onset of severe chest pain that developed while on HD. She had been established on HD for just over 3 years, after an initial period of 2.5 years on peritoneal dialysis. When peritoneal dialysis failed, she switched to HD via a left-sided internal jugular THC. This was used for 10 months until a left-sided brachiocephalic AVF was formed. The brachiocephalic AVF achieved pump speeds of 350 ml/min with a urea reduction ratio of 77%. Routine Doppler studies of the AVF, performed several months before presentation, had revealed a patent fistula with peak systolic velocity of 3.9 m/s and flow of 1800 to 2000 ml/min. A left brachiocephalic vein occlusion was identified, with blood flow draining via a large collateral vessel into the internal jugular vein. In spite of this finding, there was no associated elevation in venous pressures, difficulties needling the AVF, or symptoms, including arm swelling.
On initial assessment in the emergency department, the patient reported sharp central chest pain that radiated to the jaw and left arm, was worse on deep inspiration, and eased with opiate analgesia. There were no associated symptoms of cough, shortness of breath, nausea, or palpitations. She had completed her usual session of 4 hours of HD, anticoagulated with heparin, with 1.3-l ultrafiltration. She remained hemodynamically stable throughout the dialysis session, with no drop in blood pressure. Regular medications at the time of presentation included amlodipine, bisoprolol, doxazosin, ramipril, alfacalcidol, atorvastatin, folic acid, Sandocal (calcium carbonate; calcium lactate gluconate) with meals, Venofer (i.v. iron sucrose) 100 mg weekly on HD, and NeoRecormon (epoetin beta) 4000 units twice weekly on HD. On examination in the emergency department, 4 hours after completing HD, the patient was hemodynamically stable with a pulse rate of 83 beats per minute, blood pressure 144/86 mm Hg, oxygen saturations 96% on room air, and respiratory rate 18. The chest was clear on auscultation and heart sounds normal. Laboratory investigations at the time of presentation revealed hemoglobin 120 g/l, platelets 257 × 109/l, international normalized ratio 1.08, activated partial thromboplastin time ratio 1.40, and troponin I 24 pg/l. Additional laboratory values are shown in Laboratory values at the time of admission (a) Baseline posteroanterior (PA) chest radiograph (CXR) 4 months before admission. (b) Admission PA CXR; arrow demonstrates a widened mediastinum.Laboratory investigation, Units Results Reference range Hemoglobin, g/l 120 115–155 White blood cells, × 109/l 5.54 4.00–11.00 Mean corpuscle volume, fl 89.3 77.0–95.0 Mean corpuscular hemoglobin, pg 29.4 25–34 Mean corpuscular hemoglobin concentration, g/l 329 320–370 % Hypochromic cells 3.3 – International normalized ratio 1.08 0.9–1.2 Activated partial thromboplastin time ratio 1.40 0.85–1.15 Sodium, mmol/l 140 135–145 Potassium, mmol/l 4.2 3.5–5.0 Urea, mmol/l 3.6 3.3–6.7 Creatinine, μmol/l 354 45–120 Total protein, g/l 80 60–80 Albumin, g/l 51 35–50 C-reactive protein, mg/l 74 <5 Troponin I, ng/l 24 <16
A computed tomography angiogram ( Computed tomography angiogram demonstrating mediastinal collateral blood vessels and mediastinal hematoma lying anterior to the trachea causing anterolateral displacement of the superior vena cava (SVC).
Following admission to the renal ward, the patient underwent heparin-free HD via her AVF using low pump speeds of 250 ml/min. The HD circuit was prevented from clotting with the use of intermittent flushes of 0.9% saline, and the patient remained stable on HD throughout. Repeat blood tests demonstrated only a small drop in hemoglobin from admission 120 g/l to 94 g/l, which subsequently remained stable. The patient was observed to be hemodynamically stable for 72 hours. A repeat computed tomography angiogram then demonstrated stable appearances of the mediastinal hematoma and pericardial effusion, but with new bilateral hemothoraces. These were managed conservatively, and the patient was discharged back to her satellite HD unit without intervention. She was later discussed in the local complex access multidisciplinary meeting. A decision to attempt radiologically guided crossing of the brachiocephalic occlusion ± dilatation and stenting was made, to relieve pressure in the collateral vessels and prevent further bleeding. At the time of writing, the patient had received a deceased donor renal transplant and remained stable off HD, with excellent renal function. All vascular intervention procedures were therefore cancelled.
The rising incidence of patients commencing HD as unplanned starters has led to THC and temporary CVC being increasingly used as first-line VA in many. Factors associated with an increased risk of central venous thrombosesVariable Risk factors Catheter factors Type Peripherally inserted central catheter Polyethylene Size Increased lumen diameter Increased number of lumina Position Tip above superior vena cava–atrial junction Subclavian and left-sided lines Insertion site Left-sided catheters Femoral Insertion attempts Multiple Patient factors Hypercoagulability Malignancy Sepsis End-stage renal disease Inherited thrombophilias Previous venous thromboembolism Age Increased Medications Chemotherapy Number of previous catheters Increased
In addition to the symptoms that may result from CVTs, their presence can have superadded consequences, including thromboembolic phenomena, catheter-related infections, catheter dysfunction, post-thrombotic syndrome (edema, pain, and limb swelling) and venous hypertension.
This case demonstrates a previously undescribed risk associated with medium/long-term THC VA use in patients on HD. Our patient developed a CVT in the left brachiocephalic vein as a consequence of left internal jugular THC placement, despite placement for only 10 months. As with many patients who develop occlusive disease, collateral venous blood vessels developed and matured around this thrombus to permit blood to bypass the occluded segment.
Collateral blood vessels (collaterals) tend to be of smaller caliber than the main vessel whose function they replace. They often develop from existing vessels to form a new pathway around an occluded vessel segment.
Collateral development is stimulated by increased shear stress on the vascular endothelium, following occlusion of a major vessel. This leads to activation of complex pathways that ultimately result in altered growth factor gene expression, and in turn remodelling of the endothelium and smooth muscle cells within collateral vessel walls.
Most work surrounding collateral vessel development and maturation observes changes in arterioles, following artery occlusion. There are few studies observing the extent of these changes in the venous system, to see if and how the changes that occur within vessel walls may differ. The overall integrity of collateral blood vessel walls in comparison with major blood vessels is not well understood. It is assumed collateral vessels are more fragile than established large-bore vessels, meaning they are at increased risk of damage from minor insults. It is unclear how our patient bled from a collateral vessel, and what might have precipitated this event. One theory is that it could be related to the added stress from the large volume and turbulent flow going through her AVF. More work is required to observe the cellular aspects of venous collaterals to characterize the nature of these vessels, their associated integrity, and how/if blood flow on HD may affect them.
In conclusion, increasing numbers of patients commence HD via suboptimal VA, that is, CVC and THC. Although these methods of obtaining VA are a life-line, they should be avoided where possible to reduce the risk of associated complications. CVTs are an increasingly common complication of HD catheter insertion, which, with proper planning of VA options, could potentially be avoidable in many ( Teaching points Arteriovenous fistulas are considered to be the most optimal form of long-term VA in patients on HD. Increasing numbers of patients are commencing HD via suboptimal forms of VA (temporary CVC or THC). THC and CVC are more frequently associated with complications, including CVTs. CVTs can result in thromboembolism, post-thrombotic syndrome, collateral blood vessel formation, and, ultimately, loss of VA. Where possible, clinicians should aim to ensure patients have optimal VA formed before commencing HD. Clinicians should be mindful of the need to establish definitive VA when other methods of renal replacement therapy (including peritoneal dialysis and transplantation) are failing. CVC, central venous catheter; CVT, central venous thrombosis; HD, hemodialysis; THC, tunneled hemodialysis catheter; VA, vascular access.
All the authors declared no competing interests.
The authors acknowledge Dr. Hugh Cairns who cared for the patient during her inpatient stay.
TR reviewed the case and wrote the main body of text. MF reviewed and amended subsequent drafts and approved the final version. TA reviewed and provided the radiological images and approved the final version. FDF reviewed and approved the final version.