07/30/2025
As you may know, I was blessed over my career with a large number of interesting referrals, which form the bulk of my Facebook posts. Although just over 50% of my new patient referrals were for first-time access, the remainder were patients with problems with their existing accesses, failing accesses, "no access options", or higher risk patients. This patient with a high flow fistula came from the western part of Michigan.
------- Complex flow reduction in a patient with high-bifurcation of the brachial artery ------
The patient was a 45-year-old male referred for an aneurysmal and pulsatile left arm fistula with, arm pain, prolonged bleeding and demonstrated high flows. He denied hand symptoms but admitted to occasional shortness of breath, dyspnea on exertion, and paroxysmal nocturnal dyspnea.
A recent cardiac evaluation included an echocardiogram showing reduced global systolic function with a ejection fraction in the 35 to 40% range, wall motion abnormalities, bilateral atrial dilation, moderate to severe pulmonary hypertension with a RVS of 58 mm Hg; a stress test negative for reversible ischemia but with moderate fixed defects suggesting previous infarction in the distribution of the right coronary artery and LAD.
A recent vascular assessment in Battle Creek locally demonstrated a mean flow volume in the fistula of 5689 mL per minute and no other abnormalities other than excessive size.
On physical examination, the patient was a well-developed middle-aged male in no apparent distress, alert and conversive. He had a torturous and mildly aneurysmal left brachiocephalic fistula with a strong full cycle thrill and palpable radial pulses bilaterally. There was mild to moderate lower extremity edema. Office ultrasound demonstrated a patent sizable fistula without signs of stenosis or diverting branches. High bifurcation of the left brachial artery was noted from the upper third of the arm, with a 1 cm feeding artery proximally, and retrograde flow distally with evidence of cross antecubital collateralization from the ulnar artery by color flow Doppler.
The patient was offered a flow reduction procedure with a intraoperative fistulogram and flow measurements.
The procedure was done with regional anesthesia plus local and sedation to avoid the hemodynamic effects of general anesthesia and to allow for accurate flow measurements. The initial fistulogram demonstrated a large fistula without dramatic abnormalities and with patent cephalic arch and central veins. High bifurcation was confirmed although the retrograde arterial examination was limited by difficulty getting above the bifurcation and high flow. Flows were measured by a thermodilution method up to 4300 mL per minute.
The first part of the fistula was skeletonized and extreme thinning of the vessel wall was noted near the arterial anastomosis, making aneurysmoplasty hazardous with a risk of rupture (see "Lessons of the cases #3"), . Accordingly, the first part of the fistula from the arterial anastomosis to the lateral bend just above the antecubital crease was completely skeletonized and excised, the anastomosis being closed with direct repair of the brachial artery primarily. Re-arterialization of the fistula was performed with a 6 mm Artegraft from the artery proximal to the previous anastomosis. During the process, the artery was purged proximally and distally, showing very strong retrograde flow. After re-arterialization, flow measurements were repeated and found to be in the 3600 ml/min range.
Further flow reduction was indicated. Because of the very strong retrograde flow in the artery distal to the anastomosis, and previously demonstrated cross antecubital collateralization by color Doppler ultrasound, the artery distal to the new anastomosis was banded with a 7 mm Impra graft section to reduce retrograde flow without ligation of the vessel. Flows were remeasured and found to be in the 2300 ml/min range, showing that significant retrograde flow had been reduced. Next, a 5 cm stretch of the Impra graft was placed around the Artegraft and closed with interrupted 5-0 proline sutures until the flows were measured reproducibly in the 1300 ml/min range. The wound was closed with a quarter inch penrose drain placed in the excision bed and the patient kept overnight. The fistula remained usable for dialysis above the revision.
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Lessons of the case:
(1) Arterialized veins can grow to significant size and carry significant volumes of blood flow which can lead to complications such as distal extremity ischemia, high-output heart failure, pulmonary hypertension and right heart failure.
(2) Noninvasive ultrasound measurements of extremity blood flows are operator dependent and less accurate than thermodilution methods which require placement of an intravascular probe. Both are affected by the patient’s physiologic state including volume status, blood pressure and the effects of anesthesia. Inhalational anesthesia and IV propofol both effect blood pressure and cardiac output profoundly. For this reason, a procedure depending on accurate flow measurements is best done with regional anesthesia, local and sedation.
(3) Flow reduction in large fistulas is most commonly done by “banding”, which is a grab bag term for reducing the size of the dialysis conduit by placing ligatures or wraps around the fistula. Aneurysmoplasty (revision with reduction of size) is another option, and may be required just to allow placement of a band around the fistula. Other methods include replacement of the inflow section with a smaller diameter graft or section of vein.
(4) Patients undergoing flow reduction frequently experience immediate relief from digital ischemia or heart failure symptoms. However, long-term changes to cardiac structure and function may take a longer time to resolve or may prove to be permanent.
(5) If a vein can grow to become an aneurysmal fistula, a new vein segment or biologic graft (Artegraft or Procol) placed to reduce or moderate flow can also grow over time. Therefore, in situ inflow replacements, proximalizations, distalizations or bandings utilizing biologic materials can be expected to lose their efficacy with return of the high flow state eventually. For that reason they are not recommended in favor of a PTFE band or conduit. Aneurysmoplasty (revision with reduction of size), alone is not durable, as the revised section will start to stretch and redilate right away.
(5) Because of the risk of recurrence, once a high flow access is identified, long-term flow monitoring is recommended.
