0:06

Behind the Knife, the surgery

0:08

podcast. Relevant and engaging content

0:10

designed to help you dominate

0:12

the day. Calling

0:22

all surgical education junkies, Behind the Knife is

0:24

looking to add three new fellows to our

0:26

team this year. We are thrilled to

0:28

be adding these positions as we've got big plans for the

0:31

future and want you to be a part of them. We

0:34

are working on countless projects that will make a real impact

0:36

on surgical education. Like

0:38

our trauma surgery video atlas, comprehensive

0:40

student curriculum, global surgery

0:43

and innovation podcast series, and

0:45

our specialty oral board reviews. We

0:48

are looking for enterprising surgical residents to take the bull

0:50

by the horns, to build something

0:52

new and exciting, and to innovate. You

0:55

will benefit from ample support from the Behind the Knife

0:57

team, the use of our brand

0:59

new digital education platform, and

1:01

access to all of our resources including

1:03

illustrators, video editing, and more.

1:07

Get your name out there and build your CV by

1:09

being part of the number one surgery podcast in the

1:11

world. You will even get paid for your work

1:13

on choice projects. We are

1:15

offering a two year fellowship starting July 2024 and ending in

1:17

June 2026. Only

1:21

residents beginning their two year academic development

1:23

time will be considered and the residents,

1:25

institutions, and mentors must approve of this

1:27

fellowship. Check out the show

1:29

notes for the application link. All applications

1:31

are due March 25th. Hey

1:34

everyone, welcome back to another episode of Behind

1:36

the Knife. I'm Drew Braight here along with

1:38

Bobby Beaulieu and David Scheckman and we're here

1:41

to talk about some more vascular surgery. So

1:44

today we're going to dive into dialysis-associated

1:46

hand ischemia, or what many of you

1:48

probably know as Steele syndrome. And

1:51

because we just love to make things complicated

1:54

in vascular surgery, this has a lot of

1:56

different names. You'll hear

1:58

it called access-related hand ischemia. hemodialysis

2:01

access induced distal

2:03

ischemia or even dialysis

2:05

associated in Steele syndrome. So

2:08

for simplicity's sake we're just going to refer to

2:10

this as Steele syndrome for the remainder of this

2:12

episode. And for any

2:14

other trainees like myself I know that abcite and

2:16

vcite are in the rearview mirror but I think

2:19

before we take a deep dive into the specifics

2:21

of Steele syndrome we should do

2:23

a really brief review of some of

2:25

the high-yield basic principles in hemodialysis access.

2:28

So patients should be referred for long-term

2:30

AD access when their GFR is less

2:32

than 20 and that corresponds

2:35

to a CKD stage 4. And

2:38

when thinking of access the autogenous AB fistula

2:40

is going to be the gold standard and

2:42

that's going to be preferred to prosthetic due

2:44

to lower risk of infection and

2:47

improved patients rates. You should always

2:49

attempt to access first in the upper extremity

2:51

before looking into the lower extremity and consideration

2:54

should be given in making the

2:56

fistula or access in the

2:59

non-dominant arm first and

3:01

you should think about creating it as distally as

3:03

possible in the arm. So

3:06

the common fistula choices are going to be

3:08

the radiocephalic fistula or the snuffbox fistula, brachiocephalic

3:11

fistula or a brachobacilic

3:13

fistula. And when

3:15

you're thinking about grafts the common

3:17

choices are going to be a

3:19

forearm loop graft, brachial axillary graft

3:21

or an axillary axillary loop graft.

3:25

All patients should have vein mapping performed

3:27

prior to determine the size of their

3:29

veins and arteries with a minimum artery

3:31

size of 2.5 millimeters and

3:34

a vein above 3 millimeters. And

3:36

I'm sure we've all heard of know and love the

3:38

rule of sixes but just to quickly review a mature

3:41

fistula that's ready to use has

3:43

a flow of above 600 mils per

3:45

minute, a vessel diameter of

3:48

above 6 millimeters should be

3:50

located less than 6 millimeters from the

3:52

skin and have a cannulation segment that's

3:54

above 6 millimeters as well. So

3:56

these concepts get tested frequently and if you missed them

3:59

on this year's test Hopefully after this episode

4:01

you can steal an answer on

4:03

the test next year. No way I'm

4:05

gonna I'm not be done making some bad jokes here. So

4:07

Dave, why don't you kick us off and tell us what?

4:09

You know about Steele syndrome All

4:12

right, Drew moving away

4:14

from the bad puns Steele

4:17

syndrome refers to constellation of symptoms.

4:19

We're having hand ischemia induced by

4:21

chemodialysis fistula or graft in

4:23

other words It refers to fistula or

4:26

graft stealing or siphoning blood from

4:28

the distal tissues most commonly the hand Unfortunately

4:32

in order to really understand dialysis access

4:34

on Steele syndrome. We do need to

4:36

talk to them about physics When

4:38

you create an AV fistula or AV graft

4:41

it substantially alters flow The

4:43

downstream effect of this is alterations

4:45

to resistance and dynamics affecting

4:49

flow going from one circuit

4:51

initially, which is high resistant to Having

4:54

a low resistance circuit competing with that

4:56

high resistance circuit of the hand It's

4:59

important to note that some amount of steel we

5:01

refer to as physiologic steel is

5:03

a normal phenomenon after AV fistula or

5:05

AV graft creation Physiologic

5:08

steel is common and Noted

5:10

in up to 73% of autologous access and 91%

5:12

of prosthetic access Almost

5:16

90% of patients do have some kind of reduction

5:18

in distal blood flow that we can measure But

5:21

may not be clinically significant So only

5:23

a small subset of these patients develop

5:25

Steele syndrome and we have to remember

5:27

we're talking about a syndrome We're talking about

5:30

a constellation of symptoms So no matter what

5:32

your angiographic or duplex findings are what

5:34

we're going to focus on today is what the patients

5:37

are experiencing And this is often hand

5:39

numbness coldness pain

5:41

weakness as well

5:43

as significantly reduced blood pressure and Changes

5:46

to the tissue distally to the access When

5:49

we think about it from a physiologic standpoint Bischemia

5:52

or Steele syndrome results from inadequate

5:54

collateral circulation and ability to meet

5:56

increased demand via

5:59

Increased. The A Copper envision a

6:01

lesion leading to decrease distal perfusion.

6:04

When. We think about this for a

6:06

physiologic standpoint. Ischemia or steal syndrome results

6:08

from inadequate cloud of recirculation. This.

6:11

Can be an inability to meet increase demand

6:13

in the hand when using it. Or.

6:15

Maintain flow to the hand during our

6:17

sessions. This. All leads to

6:20

a decrease in to stop protection and the

6:22

patient experiencing symptoms. Sir. Bobby. How

6:24

common. Steals under. They. Save

6:26

What! The incidence of Steel Syndrome is

6:28

actually quite variable depending on the literature

6:30

that Uri and he can be anywhere

6:32

from four to ten percent base can

6:34

all over the place. We. Do

6:36

know that the incidence varies with the type

6:39

in the location in Dallas. His axis. Is.

6:41

Seems it significance ios injure resulting

6:43

in the scheme yeah occurs in

6:45

about one to two percent of

6:47

autogyros. Access has performed at the

6:49

wrist. And between four and eight

6:51

percent of break your base access. Is.

6:54

Summoned This goes back to your for Sally's

6:56

ally which you recall is the flow is

6:58

proportional to their radius of the vessel, race

7:00

to the fourth power. So. A

7:02

larger vessel like that break your artery

7:04

will have more flow going through them

7:06

and can result in more. Seal.

7:09

Now. They're also may explain why a

7:12

the grass have higher rates of. Dallas.

7:15

Has really to seal syndrome then ab fistulas

7:17

grass when you put him in our just

7:19

bigger and they're in the six to seven

7:21

know me to range and can result in

7:23

the higher skill rate. Than. And blood

7:25

vessel such as as about painter. The

7:28

Sylvain that would be smaller typically.

7:31

Other factors that intact and it season

7:33

the other factors that impact. No.

7:35

Risk of seal syndrome include aged over

7:38

sixty, diabetes, a history of prefer artery

7:40

disease, or coronary artery disease, Tobacco.

7:43

Use larger conduit or larger and after

7:45

most he's performed at time in Minnesota

7:47

and replacement. Female. Sex a

7:49

history of Seal syndrome not really surprising

7:52

there and in multiple previous Dallas has

7:54

access attempts typically on that limb. Almost.

7:57

All these have some intuitive physiologic. the

7:59

explanation that you can eat base association

8:01

for example, We know that vessel compliance

8:04

decreases as we age in this can.

8:06

Really? Fun to some decrease just of

8:08

well beyond a of the shown. In.

8:10

Diabetic patients hyperglycemia decreases sheer induced

8:13

they so dilatation beyond the site

8:15

of a fisher. See. Won't have

8:17

as much laser dilatation under vessels in the forearm

8:19

leading down to the hand and therefore blame me.

8:22

Want to? got that? they show and then. Results:

8:25

Or decrease collateral recruitment inflow, artery

8:27

remodel, and. And in as

8:29

you may imagine atherosclerosis in the form of

8:31

for for artery disease or which coronary disease

8:33

is a risk factor as well. May.

8:36

Increase the risk of afloat limiting

8:38

lesion in either the inflow or

8:40

an increase prefer oh this ensued

8:42

atherosclerosis in the forearm vessels like

8:44

the radio and owner wrestles. So.

8:46

Drew How do we diagnose The

8:49

Steel Syndrome? Yeah. For sure.

8:51

So you're still centered. really can be.

8:53

Somewhat. Of a clinical diagnosis so odyssey

8:55

get me get history is going exam

8:57

and these patients is quite important. So.

9:00

When thinking about the symptoms, these really can

9:02

depend and really are pre variable and regards

9:05

to the severity of the disease. So.

9:07

Typically symptoms are going to develop over the

9:09

course of weeks to months after creation, but

9:11

they can occur years after the of this

9:13

was created. And as it has

9:16

been earlier, decent into good Coolest pierce. These

9:18

shows weakness in pain and and these are

9:20

typically often either during dialysis or worse with

9:23

our says, but patient certainly can have some

9:25

is human pain in some of these symptoms

9:27

even arrest. And added later stages.

9:29

Patients can even if tissue loss from this.

9:32

So. Dakota bit more about this later. We

9:34

discuss the stages, but just gonna touch on

9:36

that now. And. Then when you

9:38

examine these patients ya buses can be

9:40

quite variable with it are often times

9:42

they'll have a cool extremity with power.

9:44

Sinews is. Delayed. Capillary resell.

9:48

And. Even some patients may have absent

9:50

pulses or signals, and there he and.

9:52

Some. Patients my had diminished sensation, a

9:54

wheat bread or even ulceration and angry

9:56

like I mention. Your wedding?

9:58

That's really helpful as to do. The impression that official

10:01

or graph when you're a die reading these

10:03

patients and that often we do improvement and

10:05

all of these symptoms that we just mentioned.

10:07

And. As an aside I think yo important

10:09

a point out here that in a patient

10:12

who presents with pain and profound muscle weakness

10:14

and media the after creation of the saw.

10:16

An abnormal pulses or signals in their

10:18

hand? That's. Really concerning Frisky

10:20

make money on my like neuropathy

10:22

and that must be considered at

10:25

that point. So prop recognition in

10:27

differentiation of Iron Man. Versus

10:29

acutely Misty Mia is important and why

10:31

decent of the fistula? The tree. In

10:33

that case, I'm sure we've all taken

10:35

some. Abs I'd be say practice

10:37

questions are not than the stem. So.

10:40

Let's say we have a patient with a

10:42

six month old break your basilica eighty six

10:45

so on and they come in with he

10:47

in pain and pierce teachers and it's only

10:49

during dialysis. But. Their symptoms are

10:51

pretty bothersome. What diagnostic tests maybe

10:53

help confirm the diagnosis is? still

10:55

sit around. Thinks.

10:58

True. So. Currently, no

11:00

clear guidelines exists for

11:02

a. Testing Definition

11:04

of Steel Syndrome. Most

11:07

of that is because we've had

11:09

multiple studies that look at pressures,

11:11

wave forms, and geographic data and

11:14

duplex. In. These patients. And

11:16

wall patients on the extreme ends of

11:18

the It's spectrum tend to have are

11:21

not have Steel Syndrome. There's.

11:23

A Really. Can. A heterogeneous

11:25

group in the middle that may have.

11:28

relatively. Normal pressures and symptoms. Or

11:30

relatively abnormal pressures? A new symptoms.

11:33

So. My work

11:35

up for this involves pressure measurements,

11:38

Pulse. Oximetry, Sometimes.

11:41

Photoplethysmography, Doppler a duplex ultrasound

11:43

as well as. Tracy.

11:45

Tiniest oxygen pressure and even

11:47

invasive in geography. So. There's

11:49

also things in the toolbox to better understand

11:51

what's causing the patient's symptoms and what we

11:53

can do about it. All.

11:55

these tests when done should be done both

11:57

with this is sheila open and the show

12:00

compress to get an idea of the physiologic

12:02

changes that happen when you compress the fistula.

12:05

I mentioned that there's heterogeneous data. One

12:07

of the previous works published in GBS

12:10

in 2015 found that the digital brachial

12:12

index or DBI of less

12:14

than 0.7 had 100% sensitivity but only a 73% specificity for Steele

12:17

syndrome. This

12:21

paper also found out that an oxygen saturation

12:23

of less than 95% was

12:26

associated with Steele syndrome. So

12:28

once again, patients may have a higher

12:30

drop in no symptoms. They don't come Steele

12:32

syndrome. They do have an abnormal pressure. Another

12:36

paper, 2005 from Vascular Medicine, the co-authors

12:38

measured digital artery pressures in patients with

12:40

and without digital ischemia. They found that

12:42

the mean digital pressure was significantly lower

12:45

in patients with Steele syndrome, 30 versus

12:47

102 millimeters of mercury

12:50

in the normal group, as

12:52

well as a digital brachial index of

12:54

0.3 versus 0.8. Some

12:58

authors have proposed using post-operative systolic

13:00

pressure index, which is the post-operative

13:02

forearm pressure divided by the

13:04

contralateral forearm pressure. Using

13:07

this, they found that 42% of

13:09

mild to moderate ischemic symptoms occur

13:11

in patients with an SPI or

13:13

systolic pressure index of less

13:15

than 0.4. Finally,

13:18

some authors have proposed that a digital pressure

13:20

of less than 50 millimeters of mercury, a

13:23

digital brachial index of less than 0.6 for

13:26

a transcutaneous oxygen pressure less than 20

13:28

to 30 are most consistent with Steele.

13:31

I think the important thing to remember is that

13:33

we have lots of noninvasive tests to look for

13:35

this. And although there are

13:37

no exact guidelines to diagnose Steele, if you

13:39

have a patient with the right symptoms and

13:42

evidence of distal ischemia on noninvasive testing, you

13:44

probably have a patient with Steele syndrome. Yeah,

13:47

Dave. And I think another point is it's

13:49

probably helpful that when you get a duplex

13:51

ultrasound, you can get some sense of the

13:53

flow that goes through that fistula. And

13:57

the measurement of flow is not necessary, as you've

13:59

pointed out. really enter into

14:01

the diagnostic criteria, but there's a

14:03

couple numbers that are probably worth

14:05

keeping in mind. Fiscula

14:07

that have a flow rate less than 600

14:10

mls per minute are unlikely to

14:12

be useful for dialysis and probably

14:14

low likelihood to have steel as

14:16

well. Whereas a high output

14:18

fiscula is one that's over 1500

14:21

mls per minute and these can

14:23

get up into the several liters per

14:25

minute category and those are really the

14:28

ones where you start entertaining the diagnosis of Steel

14:30

syndrome a little bit more. I'd

14:32

say angiography is a staple of the

14:34

workup in Steel syndrome. An

14:36

angiogram allows for a clear assessment

14:38

of other possible contributing factors such

14:40

as an inflows stenosis, an outflows

14:42

stenosis and you get clear

14:45

visualization of the steel and the runoff to

14:47

the hand. It's important to

14:49

remember to repeat the angiography both with

14:51

and without fiscula compression. You can often

14:54

do this with metal instruments you

14:56

don't have your hand in the x-ray beans

14:58

sort of a Lara style right there. You

15:01

may see a significant arterial lesion

15:04

on the inflow and outflow that could be responsive to

15:06

angioplasty and you could treat it at that time. These

15:09

types of arterial lesions are present in about 14% of

15:12

all patients with AV-axis and up to

15:14

80% of patients with symptomatic steel syndrome.

15:17

Another little tip and trick is you

15:19

should get an evaluation of the hand

15:21

itself with and without fiscula compression. Sometimes

15:24

it can be difficult to collimate your II

15:26

beam enough so that you reduce the radiation and get

15:28

a good image. If you put them

15:31

with some water

15:33

below their hand or a wet towel

15:36

it'll change the rate of x-ray

15:38

generation and make it a little bit easier to

15:40

see. So let's take the same

15:42

patient who presents for follow-up six months after creation

15:45

of a brachial bacillic AV fiscula. However let's switch

15:47

up the case a little bit and say this

15:49

patient has no symptoms but rather

15:51

was found to have evidence of decreased

15:53

digital pressure and evidence of steel on

15:55

his duplex. The patient says his hand

15:57

feels great and he successfully used the

15:59

fiscula for dialysis without any issues

16:01

whatsoever. Drew, do you need any

16:03

other workup for this case? Yeah,

16:06

I think what you're getting at here is

16:08

grading steel syndrome. So just to kind of

16:10

go through that real quick, steel syndrome is

16:12

most often split into four grades and it's

16:14

usually zero to three. I have seen some

16:17

sources that say one to four, but

16:19

the kind of textbooks that we like to read

16:22

generally say zero to three. So this

16:24

patient is probably a grade zero

16:26

of steel. So that really refers to the

16:29

fact that there's evidence of retrograde

16:31

diastolic flow, but this patient is

16:33

not having any symptoms. So for patients

16:36

with grade zero of steel, we can really

16:38

just observe them. So I guess to answer

16:40

your question, probably not. I think

16:42

we could probably schedule him for a follow-up appointment and

16:44

counsel him on symptoms really to watch out for. On

16:48

the other, in grade one, steel refers to mild

16:50

symptoms. So this is hand claudication or coolness like

16:52

we talked about. And these

16:54

symptoms, or patients with grade one, usually just

16:56

have these symptoms during dialysis. And

16:59

in some cases, they can be observed with

17:01

routine surveillance and hand exercises. But

17:03

if their symptoms are severe, meaning limiting

17:05

their ability to get through dialysis, then

17:08

you might need to do surf choir prevention. Grade

17:11

two steel refers to significant symptoms such

17:13

as pain at rest or very severe

17:15

co-audication during dialysis. And

17:17

grade three refers to patients with tissue loss,

17:20

so an ulceration, necrosis, or dangrene. And

17:22

or motor and sensory deficits. And both

17:25

grade two and grade three steel requires

17:27

surgical intervention. Okay, so let's go back

17:29

and pretend our patient has pain at

17:31

rest and evidence of steel on non-invasive

17:33

imaging. Drew, what kinds of

17:35

interventions can we offer for steel syndrome? Yeah,

17:39

so in patients with steel syndrome, the main

17:41

goals of treatment are really symptom resolution and

17:43

access preservation. Obviously, if they have a working

17:45

tissue, we wanna see that at all costs.

17:48

So patients with transient mild symptoms, like

17:50

we kinda talked about, can be managed

17:52

expectantly with reassessment and

17:54

their remaining in blood pressure management.

17:56

However, in patients with grade two

17:58

or three steel syndrome, surgical intervention

18:00

is needed. So there's

18:03

two basic strategies. There's access

18:05

flow reduction and that's coupled patients with

18:07

high flow AB fistulas. So like we

18:09

talked about those with the flow rate

18:11

of above 1500 milliliters per minute and

18:14

then augmentation of the distal arterial

18:17

flow to alter hemodynamics and improve

18:19

the digital perfusion and

18:21

those patients with lower normal flow AB

18:23

fistulas. So the options

18:26

that we have include banding, revision

18:28

using distal inflow which we call

18:30

Rudy, R-U-D-I, proximalization of

18:33

arterial inflow also known as

18:35

PI and distal revascularization

18:37

with interval ligation

18:40

or drill. And

18:42

then obviously there's a role for

18:44

arterial angioplasty as well. And

18:46

as a last resort which

18:48

just makes us all sad and nervous to

18:50

even say out loud on this podcast, ligation

18:53

can be used in those with limited life

18:55

expectancies, severe tissue loss

18:57

or poorly functioning access. So

19:00

I think it's really helpful as you go through

19:02

these options, we're kind of going to go through

19:04

each independently. Really encourage you to check out

19:06

the link in the show notes to this paper from 2016

19:09

in the Journal of Vascular Access. This

19:12

article has great diagrams of each

19:14

of these options so it's really

19:16

helpful to kind of check on that as

19:18

we kind of go through each of them and have like

19:21

a little graphic to watch them. Awesome,

19:23

so let's talk about banding first. So

19:25

in general, banding refers to creating

19:28

a stenosis near the arterial anastomosis

19:30

of the AVF or

19:32

as Dave likes to call it, just

19:34

as anastomosis. Decreasing the

19:36

radius and as you recall from your brief

19:38

physics review that we just had leading to

19:41

an increased resistance in the fistula and thus

19:43

decreased flow through the fistula. There

19:45

are many ways you can do this. You can

19:48

let your fellow complete the anastomosis. It can also

19:50

be done via suture plication, a single

19:52

tie, or wrapping a constrictive prosthetic

19:55

cuff. However, determining the

19:57

exact degree of stenosis needed is quite

19:59

helpful. quite difficult and is really more of

20:01

an art than a science, because not enough

20:03

stenosis and the steel will be improved, too

20:06

much stenosis and you risk thrombosing off the

20:08

fistula. Many of the

20:10

early series of bandings based the degree of

20:13

banding on intraoperative assessments of distal perfusion alone,

20:15

and were limited by high rates of access loss.

20:19

So precision banding is a technique that

20:21

uses accurate measurements of the degree of

20:23

flow reduction in conjunction with one of

20:26

the aforementioned banding techniques. And

20:28

on final analysis, access below of 700 mls

20:31

per minute is an important cutoff

20:33

for maintenance of AV access

20:36

patency. And those that

20:38

are above that have a 74% patency versus those

20:40

that are below it have a 38% patency.

20:44

Suggesting the reason for the earlier failures of

20:46

banding may have been just tightening too much

20:48

and lowering the flow rates. However,

20:51

banding is not commonly done in

20:54

contemporary practice as it is still

20:56

limited by variable outcomes and the inability to

20:58

more accurately determine how tight you need to

21:01

make the band. Many

21:03

surgeons now advocate for the

21:05

Miller technique, which stands for

21:07

minimally invasive limited-ligation endoluminal assisted

21:09

revision. The Miller

21:12

technique uses a percutaneous

21:14

4-5mm endoluminal balloon placed

21:16

as a sizing dowel with

21:18

a suture placed around access with the

21:20

balloon inflated via a small incision. Series

21:24

describing this technique demonstrated that significant

21:26

clinical improvement occurred in 89%

21:28

of patients with an early thrombosis rate

21:30

of only 4.4%. Although

21:33

the role of banding is still debated, it

21:36

remains an option for the particularly useful for

21:38

Steel syndrome in high flow AV fistulas. However,

21:41

another technique has

21:43

described banding between puncture sites in

21:45

low flow AV fistulas to

21:47

maintain a pressure gradient between the arterial

21:49

and the venous puncture site. Every

21:53

fan knows the right player and the right

21:55

position can be a game changer. Put

21:58

life block between your identity and identity. To

22:00

monitor and alert you to threats you could

22:02

miss. Plus, with a U.S.-based

22:04

restoration specialist on your team, you won't

22:06

have to face drained accounts, fraudulent loans,

22:09

or other losses from identity theft alone.

22:12

All backed by the LifeLock Million

22:14

Dollar Protection Package. Change the game

22:17

on identity theft. Save up to

22:19

25% your first year at lifelock.com/aware.

22:23

If you own a vehicle with less than 200,000 miles

22:25

and have an auto warranty about to

22:28

expire or no warranty coverage at all,

22:30

listen up. CarShield has a low-cost, month-to-month

22:32

vehicle protection plan that covers more parts

22:34

than ever. Visit carshield.com/audio to find out

22:37

how you can pay almost nothing for

22:39

covered auto repairs. Drivers who activate this

22:41

vehicle protection today will also receive free

22:43

roadside assistance, free towing, and car rental

22:46

options at no additional cost. Get your

22:48

free quote today at carshield.com slash

22:50

audio. That's carshield.com/audio.

22:54

So Dave, how about Rudy, besides

22:56

being an all-time classic sports felon

22:59

and lead into the character of Samwise Ganji

23:02

in the Hobbit films, can you

23:04

explain that to us? Absolutely,

23:07

Bobby. So Rudy, also

23:09

known as revision using

23:11

distal inflow, in

23:14

this procedure the avificulate is ligated

23:16

to its origin or a

23:19

vein or prosthetic conduit is used to

23:21

establish inflow from a more distal arterial

23:23

source, usually proxible

23:25

to the mid radial artery. Again,

23:28

if you aren't driving a car or riding your

23:31

bike, take a second to pause and pull up

23:33

the article with the pictures. It will be helpful,

23:35

I promise. The way this works

23:37

is using a smaller distal artery as your

23:39

inflow causes increased

23:41

resistance and the fistulate

23:43

is lengthened. By increasing the length,

23:45

that also increases resistance. This

23:49

reduces the flow in the avificulate and can

23:51

help relieve symptoms. One

23:53

thing I want to say though is in practice, Rudy can

23:55

be really hard to find a good patient for because

23:58

most of these patients have distal inflow. peripheral

24:00

arterial disease which is why

24:02

the access is higher than a distal

24:04

target to begin with. So

24:08

looking at studies evaluating Rudy, they

24:10

have good symptom resolution and good access patency.

24:12

A review of 130 patients

24:14

from 11 articles noted an 82% success rate to

24:19

find as resolution or recruiting symptoms at 12

24:22

months. However, 11% of

24:25

officials did require a ligation for

24:27

continued symptoms and another 7.5% thrombosis.

24:29

Other things to think about

24:33

recurrence was noted at 50% of patients

24:36

at three years. Another

24:38

limitation is patient selection. As

24:40

I talked about, patients with distal

24:43

peripheral disease and small arteries beyond

24:45

where previous anastomosis was would not

24:47

be a candidate for Rudy. They

24:49

would need a new inflow procedure. Oftentimes

24:52

patients will be candidate for Rudy because

24:54

of this reason and we have to

24:56

talk about other options such as PI. Yeah

24:59

PI or proximalization of arterial inflow is

25:01

really all in the name. In this

25:03

technique the inflow for the AV access

25:05

is moved more proximally up in the

25:07

arterial level. Now I know

25:09

you're probably thinking this dude just talked all

25:12

about physics and how a bigger vessel increases

25:14

the flow and therefore could increase the risk

25:17

of steel syndrome. So how does

25:19

proximalization actually help with steel syndrome?

25:22

Well the first descriptions of PI or

25:24

by Zarnow et al describe ligation of

25:27

the anastomosis in conversion to a more

25:29

proximal inflow using just a

25:31

4 to 5 millimeter PTFE interposition.

25:34

In this case because PTFE is less compliant

25:36

and it's a smaller diameter, no

25:39

longer length actually helps lead to an

25:41

increased resistance and decreased flow through the

25:43

graph. However, some groups have described

25:45

the technique with vein and have similar results.

25:48

In that case the proximal arteries

25:50

diameter in higher capacity creates

25:53

lower pressure drop across the anastomosis

25:55

at similar flow rates. So

25:58

our simple placelae equation doesn't explain

26:00

everything in this scenario. The

26:03

primary advantage of PI is

26:05

preservation of the native arteries'

26:07

continuity. Symptom resolution occurred in

26:09

84% of patients, the

26:12

remaining significantly improved. Access

26:15

primary patency was 87% at 12 months, 67% at 3

26:17

years. Thorvin et

26:22

al. confirmed similar results but found that patients

26:24

with severe tissue loss did it

26:26

poorly. So last but not least,

26:29

what about the drill? Yeah,

26:32

so drill stands for Discal Revascularization with

26:34

Interval Legation. It always makes me cringe

26:36

a little bit to ligate a normal

26:38

artery. This was

26:41

originally described in the late 80s and is

26:43

now considered the gold standard by many vascular surgeons.

26:45

A drill consists of creating a

26:48

vein bypass originating 7-10 cm proximal

26:50

to the axis and esptomosis and

26:53

terminating it distal to the ligate artery.

26:57

Again, check out the

26:59

pictures in the article to help you keep

27:01

track of these different techniques. I

27:04

promise we don't get any royalties from

27:06

this article. In

27:09

the drill, retrograde flow is preserved

27:11

and a new bypass creates a

27:13

low resistance pathway to the peripheral

27:15

vascular bed. Of note,

27:17

typically when my practice prior to doing

27:20

a drill procedure, I performed upper extremity

27:22

angiography to confirm that the distal target

27:24

for bypass is adequate diameter without

27:27

significant calcifications. Long-term

27:30

results are excellent for both symptom

27:32

resolution and access patency with 89-100%

27:34

freedom of symptoms

27:37

and 73-100% patency depending on the

27:39

series. Recent

27:42

meta-analysis found best results with saphenous

27:44

vein conduit with resolution of symptoms

27:46

at 81% of patients and

27:49

patent fistulas at a mean of 22 months.

27:53

There are drawbacks to the drill. This includes perioperative

27:55

mortality as high as 6.8%, just putting in context,

28:00

how sick these patients really are. There's

28:03

also wound complications in the 10 to 20%

28:05

range, as well as dependence of the hand

28:11

on the bypass. So

28:13

we're taking their native artery, replacing

28:15

it with a bypass with 2-nastomosis

28:17

echinos, and

28:20

completely dependent flow to their hand

28:22

is off this bypass. Some

28:24

flow may be maintained to lead

28:27

to developmental collaterals, which could also

28:29

maintain distal perfusion if the bypass

28:31

occludes, but I

28:33

wouldn't tell a patient everything's going to be okay if

28:35

the bypass goes down. Well, what

28:37

a great view. Thanks, guys. I

28:39

don't know if I should be thanking you or

28:42

crying about all those physics equations, but I guess

28:44

they were somewhat helpful to hear how all this

28:46

stuff works. So I mean, with

28:48

all these options, how do we choose which

28:50

treatment to offer our patients? Yeah,

28:53

really, treatment should be individualized based

28:55

on a combination of the severity

28:57

of the patient's symptoms, the patient's

28:59

life expectancy, access flow rates,

29:01

meaning is it high, is it low, is

29:03

the distal even being used? Are

29:06

there other access options, specifically in

29:08

that limb or not? What

29:10

are the current inflow options, and what kind of

29:12

conduit does the patient have? So

29:14

Rudy, Drill, and Pie generally have similar

29:16

outcomes, but they require a little bit

29:19

bigger of a surgery with a higher

29:21

morbidity and mortality. That's

29:23

in comparison to ligation or banding, which is

29:25

better suited for those with limited life expectancy.

29:28

But as we talked about with banding, it's

29:30

hard to establish how much you need

29:32

to limit the graft, and that may

29:34

both decrease your effectiveness at treating steel

29:36

and increase the risk that you thrombose

29:38

off the excess, as well

29:41

as it might require multiple interventions. So sometimes when

29:43

you add up multiple interventions, you

29:45

get a higher overall risk. Most

29:48

cases of steel syndrome are high flow, meaning in autogenous

29:50

grafts, you have a flow higher than 800 mls per

29:52

minute. In prosthetic grafts, you

29:54

have a higher flow than 1200 mls per minute. In

29:58

less than a third of patients that present with steel, you can use a field

30:00

syndrome have either low flow or normal flow.

30:03

And in those, it's often due

30:05

to poor collateral circulation or atherosclerosis.

30:08

Both Rudy and Drill traditionally

30:10

require autogenous conduit as described,

30:13

whereas the PI uses PTFD. Finally,

30:16

patient's anatomy often plays the most

30:18

important role. A Rudy

30:20

cannot be performed if there is inadequate

30:22

distal inflow, which is often the case.

30:26

I think the best way to hammer this home is to go

30:28

through a case or two. But before we

30:30

cover that, I will mention a similar entity

30:33

called Palmer-Arched Steel Syndrome, or

30:35

PASS, which occurs

30:37

when retrograde flow through an intact

30:39

Palmer arch results in an adequate

30:42

digital flow in those with radiocythallic

30:44

AB access. You can think

30:46

of it basically as blood being stolen only from

30:49

the hand and blood going up in a retrograde

30:51

fashion to the radial artery out of the Palmer

30:53

arch. Treatment is ligation

30:55

or coil embolization of the distal radial

30:57

artery just beyond the fistula creation site.

31:01

It is critical to evaluate the ulnar artery

31:03

and Palmer arch patiency prior to the slightation,

31:05

most typically with an angiogram. OK,

31:08

with that our way, let's get into a

31:10

few cases. OK,

31:13

great. First off, Drew,

31:15

you can't answer peritoneal dialysis.

31:19

OK. So for a

31:21

first case, you have a 60-year-old woman

31:23

with a history of tobacco use,

31:25

hypertension, diabetes, and the sage-reel disease who

31:28

is on intermittent human dialysis via

31:30

left brachial cephalic AB fistula that

31:32

was placed six months ago. The

31:35

patient has pain and peristegis during her

31:37

dialysis that are very bothersome and have

31:39

resulted in her missing dialysis days on

31:41

more than one occasion. An

31:43

exam she has palpable but diminished pulses in

31:45

the left arm and

31:47

intact sensation to light touch. Doppler

31:51

shows triphasic flow in her

31:53

left subclavian, but biphasic flow

31:56

in her brachial, radial, and

31:58

ulnar arteries, all distal. to

32:00

the avi fistula anastomosis. Her

32:04

left digit pressure and waveforms are

32:06

low at rest but increase with

32:08

fistula compression. Drew, how would

32:10

you approach this patient? Well,

32:12

I guess since I can't discuss peritoneal

32:15

dialysis with her, I'll just discuss

32:17

Diehl syndrome. So I think she probably

32:19

has grade one's Diehl syndrome, at least

32:22

that's what it sounds like. So

32:24

this still does appear to be pretty severe

32:26

to her and I think this warrants further

32:28

workup and intervention which is based on her

32:30

symptomatology. Given that she

32:33

has triphysic flow at her subclavon or

32:35

even biphysic flow distal to that, I'm

32:37

concerned that she might have a potential

32:39

arterial inflows stenosis. So

32:42

given that concern, I think I'd book

32:44

her for an angiogram obviously after doing

32:46

a full history in physical and I

32:48

certainly would counsel her on stopping smoking.

32:53

All right, so the angiogram

32:55

shows left axillary artery stenosis,

32:58

approximately 80%, approximately

33:01

left brachial artery stenosis, about 90% and

33:03

evidence that steel does improve a fistula

33:06

compressor. You balloon

33:08

angioplasty the stenosis with improvement to less than

33:10

30% residual stenosis

33:13

and you repeat the angiogram of

33:15

the fistula and the distal hand still shows

33:17

evidence of steel that improves a fistula compression.

33:21

So, you've improved

33:23

the stenosis but you still have

33:25

angiographic evidence of steel syndrome. What

33:28

do you do now? Well,

33:30

I think that you first need to

33:32

just see how she's doing. I mean,

33:34

we've treated some inflows stenosis so her

33:36

symptoms might have improved even though she

33:38

still has radiographic steel. So

33:40

I guess I'd wake her up and chat with her about that

33:43

and give her some time to see if she

33:45

flies and if she doesn't improve, then

33:47

we can talk about doing an open-air version. Yeah,

33:50

exactly. In this case, the patient's

33:52

steel is primarily from her inflows stenosis. She

33:55

ended up doing well after her angioplasty

33:58

and we've been following her for her first symptom. Last

34:00

I heard she was asymptomatic and

34:02

hadn't missed any more HD sessions and

34:04

was even working on quitting smoking. All

34:08

right Drew, you're still in the hot seat

34:10

for the second one. So for our second

34:12

case, we have a 54 year old male

34:15

with a history of hypertension, hypo leukemia, diabetes,

34:17

a right nephrectomy for renal cell carcinoma and

34:20

NSA adrenal disease on hemodialysis

34:22

through a left brachial,

34:25

bacillic, AV fistula placed about two years

34:27

ago. He reports symptoms

34:29

of left hand coolness, numbness and pain over

34:31

the past two to three weeks and

34:34

more recently decreased fine motor function as

34:36

well. He especially experiences

34:38

coldness and pain during hemodialysis.

34:41

On exam he has a palpable but diminished

34:43

pulse in his left arm and decreased sensation

34:46

to light touch on the left compared to

34:48

the right. His left

34:50

digit pressures and waveforms are low at rest

34:52

but increase with fistula compression. Euplex

34:55

reveals a high flow AV

34:57

fistula. How are you going to manage this

34:59

one? Yeah, so I think

35:01

this patient appears to have grade

35:03

two steel and really that seems to

35:06

be that his symptoms are at rest.

35:08

This seems pretty severe for him. It

35:11

certainly sounds like this is probably a high

35:13

flow AV fistula because

35:15

you told me that. Your

35:17

powers of repetition are amazing. I

35:22

think in this setting I think I'd still

35:24

just offer him an angiogram first and certainly

35:26

do fistula, an angiogram with and without fistula

35:28

compression to see where we're at. Perfect.

35:31

Alright, so the fistula gram shows evidence of

35:34

steel syndrome that does indeed improve with fistula

35:36

compression. His brachial artery

35:38

and proximal radial artery appear healthy without

35:40

evidence of stenosis. He has

35:42

a patent ulnar artery but a

35:44

small caliber and calcified mid to

35:46

distal radial artery with

35:48

an intact palmar arch. Is

35:51

there an operation you would offer him and which one? Yeah,

35:55

I think I'd discuss a few options

35:57

with him. He seems to me...

36:00

Criteria for a drill just based on

36:02

the anatomy you described for me But

36:04

I certainly think that other options could

36:07

be a banding or a pie and

36:09

I suppose you could even try a

36:11

Rudy As long as he's

36:13

a Hobbit fan but

36:15

I'm Pretty sure that

36:17

the distal to mid radial artery

36:19

disease would probably make Rudy not

36:21

a good call here So

36:24

it certainly make me skeptical about so I

36:26

guess just kind of based on our discussion.

36:28

I'd still lean towards a drill Yeah,

36:30

and that's what we ended up doing

36:32

a drill using left great saphenous vein

36:34

as the conduit the patient did fine

36:36

postoperatively and had an improvement in both

36:39

the pain and numbness and Had

36:41

no more symptoms at rest and

36:44

I would say you know If you're looking

36:46

at how to answer questions about steel syndrome

36:49

in your mind You should pretty much

36:51

be considering a drill first after you've

36:53

done your work up Provided the anatomy

36:56

makes sense and then work through the

36:58

rest of these after that It's just

37:00

tends to be the standard of care and a lot

37:02

of patients do meet criteria for it. So great answer

37:04

on that one Cool.

37:07

Well, thank you guys for a really comprehensive

37:09

and nice overview of steel syndrome And thanks

37:11

for giving me the opportunity to answer some

37:13

questions in front of a bunch of listeners.

37:15

So I look super smart So

37:17

as a quick recap, you know We've

37:19

reviewed some high-yield pearls regarding the basics

37:22

of dialysis access the incidence and risk

37:24

factors for steel syndrome We've talked

37:26

about kind of general diagnostic approach and

37:28

presentation We did a deep

37:30

dive of the non-invasive studies and the

37:33

cervical options including banding drill Rudy and

37:35

pie And last but not least

37:37

we reviewed some physics concepts that I'm sure you were

37:39

all hoping you could forget further We

37:41

hope you enjoyed this episode and found something you can

37:43

take away from this and apply to your practice Even

37:46

if you're not in vascular surgery and as always thanks

37:48

for listening and until next time dominate the day Be

37:52

sure to check out our website at www.behindtheknife.org

37:54

for more great content. You can also

37:56

follow us on Twitter at behind the

37:58

knife and Instagram at Behind the Knives

38:00

podcast. If you like what you hear,

38:02

please take a minute to leave us

38:04

a review. Content produced by Behind the

38:06

Knife is intended for health professionals and

38:08

is for educational purposes only. We do

38:10

not diagnose, treat, or offer patient-specific advice.

38:12

Thank you for listening. Until next time,

38:15

dominate today. Every

38:26

fan knows the right player in the

38:29

right position can be a game changer.

38:31

Put LifeLock between your identity and identity thieves

38:33

to monitor and alert you to threats you

38:36

could miss. Plus, with a

38:38

U.S.-based restoration specialist on your team, you

38:40

won't have to face drained accounts, fraudulent

38:42

loans, or other losses from identity theft

38:45

alone. All backed by

38:47

the LifeLock Million Dollar Protection Package. Change

38:50

the game on identity theft. Save

38:52

up to 25% your first year at

38:54

lifelock.com. If you only have a 401k,

38:56

you're not getting the most for retirement. Wait, what?

38:58

Add a Robinhood IRA on top, then they'll boost

39:01

it by 3%. You can do that?

39:03

And if you transfer in any retirement account, you get 3%

39:05

on top of that. Is there

39:07

a limit to the match? No limit. Robinhood

39:09

Gold gets you the biggest contribution match of

39:11

any IRA on the market. Sign up for

39:13

Robinhood Gold at robinhood.com/boost by April 30th. Subscription

39:15

fees apply. Investing involves risk. 3% match requires

39:18

gold for one year from first match. Must

39:20

keep IRA for five years. Match on transfer

39:22

subject to additional terms and conditions. Robinhood Financial

39:24

LLC. Member SIPC. Get. Ahead of

39:26

postage rate increases this year. with stamps.com

39:28

it's like your own personal post office.

39:31

Sign up with promo Code program for

39:33

a four week trial plus free postage

39:35

and a free digital scale. Know long

39:37

term commitment or contracts that stamps.com code.

39:39

Program. You

39:55

won't have to face drained accounts, fraudulent loans

39:57

or other losses from identity theft

39:59

alone. All backed by

40:01

the LifeLock million dollar protection package.

40:03

Change the game on identity theft.

40:06

Save up to 25% your first

40:08

year at lifelock.com/aware.