Office-Based Labs

The Transpedal Approach is the Future of Peripheral Intervention in Office-Based Labs

Farhan Ali, MD, MPH, MA, FACC, FSCAI, RPVI

Heart Center of North Texas, Fort Worth, Texas 

Farhan Ali, MD, MPH, MA, FACC, FSCAI, RPVI

Heart Center of North Texas, Fort Worth, Texas 

Can you describe your history and practice?

I am an interventional cardiologist and have been in practice a little over 10 years. I do a wide variety of procedures, ranging from peripheral interventions on the legs to coronary interventions and structural heart procedures. I have been with a private practice for the last 10 years, Heart Center of North Texas, in Fort Worth, Texas. We practice at four hospitals, three in Fort Worth and one 35 miles west in Weatherford. Within Fort Worth, there is quite a bit of peripheral vascular disease. The majority is handled by vascular surgeons, but many interventional cardiologists do perform complex peripheral interventions, including iliac, superficial femoral artery (SFA), and below-the-knee interventions. I have been doing peripheral interventions for the past 10 years and two of my partners have been involved in peripheral vascular intervention for about 20 years. Our fourth partner is relatively new and has been doing peripheral intervention for about 3 or 4 years. Our group opened an office-based laboratory (OBL) 4 years ago. Compared to the hospital setting, an OBL, to make an analogy, is just a different canvas to practice the art of peripheral intervention. It is not necessarily better or worse than a hospital system, but each setting has its own advantages and disadvantages. In the OBL, we predominantly treat patients with disabling claudication despite optimal medical therapy, who have failed exercise walking programs. We do treat some patients with limb loss and ulceration in the OBL, but case selection is crucial.

You don’t need an ambulatory surgical center (ASC) to perform peripheral interventions?

That’s a great question. You can do peripheral intervention in an OBL as well as in an ambulatory surgical center (ASC). Our lab is strictly an OBL, so we do not do coronary procedures, or pacemakers, defibrillators, or any electrophysiology-related procedures in our lab.

How is it set up?

There is one procedure room and a separate holding area in the back with six beds where patients recover from their procedures. We use a mobile C-arm (Philips Veradius Unity) and have an ultrasound on site (Fujifilm Sonosite) that we can use for access. The waiting area has a reception desk and can seat 10 to 15 people, but usually we only have one to two families at a time. Now with the Covid-19 pandemic, we only allow one family member in the waiting room. When the prevalence of the virus was higher in our area, family would have to sit in their car in the parking lot or come back after the procedure.

Tell us about your use of a transpedal approach for your peripheral procedures. 

We are using the transpedal approach more and more in our OBL. Transpedal access for peripheral interventions is a natural progression. Use of this access site has changed the patient’s entire experience, similar to the shift to radial artery access for coronary procedures. When we opened our office-based lab in 2016, about 27 to 30% of our cases were via the transpedal approach with ultrasound guidance. In 2017, we moved to about 50% transpedal as our first approach and the next year, 2018 to 2019, we were at about 70% transpedal. Today, we are approaching 90% transpedal access. The patients with peripheral arterial disease who experienced a groin approach in the hospital setting or elsewhere and then have a transpedal approach love it. They don’t have to lay flat immediately after the procedure, which is a benefit for a lot of our patients who have chronic back problems. They have less waiting time in the procedure room. They are walking out, on average, two hours after the procedure. In our OBL, we may fix a chronic total occlusion (CTO) in the SFA and two hours later, the patient walks out with a band-aid on their foot. All four interventionalists in our practice are increasingly choosing a transpedal approach. The procedure time is shorter: our average procedure time now is about 30 minutes. Our contrast use is less because we are taking selective angiograms through the catheter from the pedal approach and these are smaller vessels below the knee. We can take selective angiograms with our C-arm to get better resolution rather than the typical method, which is a runoff where you shoot from the femoral and follow the leg down the table. We get much crisper, sharper images, and because imaging is so selective, our contrast use is reduced. My average contrast use for a peripheral intervention is about 30 to 40 ml of contrast over an average procedural time of 30 minutes. Another advantage is if there is embolization distally in the vessel you are working on, the sheath is right there in the ankle. Open up the valve and the clot will come right out. Whereas if you are working from the femoral approach, now you have to go down to the foot to find it, and that is a very cumbersome, long process and not always completely successful. 

When we go transpedal, most of the time it is in patients that are failing medical therapy and failing their exercise walking program. They are still symptomatic and their quality of life is reduced because they are not able to walk without claudication pain, despite conservative management. Let’s say the patient is symptomatic in the right leg. Our practice has very good non-invasive cardiologists who have a very high correlation with their non-invasive ankle-brachial indices and peripheral arterial ultrasounds. We have a higher than 95% correlation with corresponding angiograms. If they believe that there is a 100 percent occlusion in the proximal SFA of the right leg, then there is good certainty we will find exactly that when we do the angiogram. I will use transpedal access and we will do selective angiograms with a support catheter such as a Rubicon catheter (Boston Scientific) or something that has an .035-inch diameter. We will be able to then figure out what we need to fix, and do atherectomy or percutaneous transluminal angioplasty and stenting, or some variation thereof. Sometimes we will use intravascular ultrasound to get a better definition of plaque burden evaluation and vessel sizing, especially in our patients with renal insufficiency requiring use of CO2 gas angiograms, which is available in the OBL. The time of the procedure is short, the contrast is much less than I would use in a procedure from the groin, and then after the procedure, the patient can immediately sit up. 

I do avoid looking at the other leg at the same time, which is a different strategy we use in our lab and is better for the patient. Going up and over the aortoiliac  bifurcation area from a transpedal approach can be done, but you are going to use a lot more contrast. If the patient has no symptoms on the other leg, why even look at it? If they do have symptoms, when we bring them back, we are going to fix the other leg anyway and so we will do the diagnostic and intervention at the same time. If there is difficult anatomy, then we might get a computed tomography angiography (CTA) runoff from radiology in order to have a better idea of what to fix. Typically that would be more for the aortoiliac areas. 

Can you share more about your use of intravascular ultrasound?

We use an OptiCross IVUS catheter (Boston Scientific) on a number of our cases to help guide intervention. Not all cases need IVUS, but for the cases where we do need it, IVUS helps reduce our contrast load even further. I’ve had some patients with chronic renal failure where we have only used 10 ml of contrast. It also takes the guessing out of stent/balloon sizing and whether atherectomy is needed.

What sheath size do you use when going transpedal?

Many people will start with the 4 to 5 French (Fr) diameter sheath, but we automatically go with a 6 Fr sheath, similar to the transradial sheath. We ultrasound the vessel first and if it is greater than 2.5 to 3 mm in diameter, we don’t have any issue advancing a 5 to 6 Fr Glidesheath Slender sheath (Terumo). If we use ultrasound and the vessel is a 1.5 mm vessel, then it may not be possible to approach from that vessel and we switch from the dorsalis pedis to posterior tibial or peroneal in order to find a better lumen vessel. Even if there is a single-vessel runoff where only the anterior tibial is open and the peroneal and posterior tibial are occluded, we have not found that going through the dorsalis pedis further compromises the foot or causes problems. There has been concern expressed nationally that you might shut down the distal vessels, but in our four years’ experience of doing over 600 cases, we have not had a single patient come back with an occlusion of that vessel because of the sheath. We do routinely check with Doppler immediately afterwards, but not again on post procedure follow-up. We have had to do repeat peripheral interventions on a few patients that might have some instent restenosis, and we access them the same way without difficulty. We also have not had any infections at all through the foot. We normally give patients enough heparin or anticoagulants to keep an ACT above 250. In some of the patients that have GI bleeding, we are able to reduce our amount of anticoagulation, because the speed of the procedure is so quick, and with a pedal approach, we don’t have a big 45 cm sheath that is up and over the aortoiliac bifurcation with long indwelling time. We do still try to maintain ACTs above 250 in these patients, but can be a little less generous with the anticoagulation. On the contrary, if patients are on Eliquis or coumadin, or are on blood thinners because of a blood-clotting disorder or hypercoagulable state, when we go from the pedal approach, we don’t worry too much about these patients restarting their blood thinners the same night or soon after the procedure, because it is a much smaller vessel and it is easier to gain control with manual pressure.

Is manual pressure typically used to obtain hemostasis with a transpedal approach? 

We use manual pressure. We have used something similar to a radial pressure band on the ankle, but for the most part, we can gain hemostasis within 5 to 10 minutes with light pressure. When we see patients in follow-up a week to two weeks later, they are often surprised that there may be no evidence of the access. I sleep better at night, knowing that I am not going to get a phone call for a possible, dreaded retroperitoneal bleed from groin access. You have one retroperitoneal bleed in your career and you never forget it. That’s why I think we have been moving so aggressively to radial and transpedal approaches. 

Does having a regular team in your OBL help with the transpedal approach?

Yes. We have one full-time radiologic technologist and one full-time nurse. Our team goes through the same process each time to prep the leg. We use 3 applications of standard ChloraPrep (BD) to prepare the site and have had zero infections over the last four years. Over those four years, we have done about 1200 peripheral interventions in our OBL and out of those, close to 700 were via a pedal approach. Prepping the foot and finding the vessel with the ultrasound have become second nature, simply because we have done so many. In contrast, in the hospital system, you don’t know who your team is going to be that day. You can request certain people, but you may have somebody that is not really adept at prepping the foot for a transpedal approach, because it is not a very common approach around the country, although I do think it is gaining more and more traction. I always joke that transpedal is the new transradial, because we are going to move in that direction. I think the future is going to be the transpedal approach. 

What do you think about the future of OBLs?

Peripheral procedures are going to increasingly move to an office-based system or an ambulatory surgical center, although we still do hospital procedures. Some insurance companies require a hospital-based procedure. Other reasons may be that the patient prefers to go to a hospital or has higher risk features that would be better suited to a hospital-based setting, such as a higher risk of bleeding, anemia, an advanced age, or certain comorbidities. Case selection is essential for an OBL. Safety comes first. The issue with the hospitals are that the cath labs are usually dual-purpose labs. If a hospital has 4 or 5 labs, for example, 3 of the labs may have digital subtraction angiography for peripheral intervention, but also function as a coronary lab. Let’s say I schedule John Smith at the hospital at 8:00 in the morning for an elective outpatient procedure, but an acute MI patient comes in. Other labs are in use and the next thing I know, my patient is bumped or moved until the emergent patient is treated. Often, as a result, your entire schedule has been compromised. You may have a clinic that day after procedures in the morning, so now all of your clinic patients are moved back. It can be detrimental to your whole day as a physician, as well as very irritating from a patient’s perspective, if you are pushed back or moved. That is the reason why we moved to an OBL for procedures. I do roughly 10 to 20 cases per week in the hospital. I typically will pick one day to do all my elective procedures in the hospital and have no office hours that day, because I know that if you have a few cases over the entire week, there is a chance that the physician in front of you is going to be slower or have delays or complications, and then you are pushed back. Over time, as you can imagine, you end up losing a lot of time with your family. We are always trying to find a way to be more efficient and better serve our patients in that regard as well, so that it is not as frustrating for them. I believe OBLs allow a physician more control over their time while providing multiple benefits to patients.

Do you have a business partner for your OBL?

Yes, and it is important to have the right managing entity. We started a partnership with RPNT Management Services, Inc. They are not invested partners, but manage all of the financial aspects of our OBL: billing, HIPAA, dictations, records, any problems with imaging equipment, any loans, etc. A good business partner is critical to running a successful lab, because when the billing, accreditations, and various administrative aspects are properly taken care of, then the physician can just worry about the patient. 

How has Covid-19 affected your OBL?

Whether true or not, patients have the perception that they are going to be higher risk for getting the coronavirus at a hospital. Data are coming out in Fort Worth specifically that this is not true — patients can go to a hospital safely and not be at an increased exposure for coronavirus. I don’t know what we will eventually determine regarding the ability to have visitors and loved ones staying with family, but I think patients are feeling like they are going to be less likely to get exposure in an OBL. In an OBL, there is less contact and no registration, because it is taken care of in the office beforehand. As we move into the use of telemedicine and less invasive approaches, we are moving more and more towards very short hospital stays and same-day discharge for elective procedures. In many cases, OBLs are a cheaper option for many insurance companies and for the patient in general, and those costs can translate down. However, I would be cautious in saying that we can do everything in the OBL. The key is case selection: knowing who is going to benefit from being in the hospital and who will benefit from the OBL. 

It sounds like you are not limited with transpedal access.

More people should be aware of the transpedal approach and that it is a viable option for daily use. We have fixed iliac arteries from the transpedal approach, using a 6 Fr sheath. We have fixed SFAs and chronic total occlusions. We have revascularized below-the-knee arteries, including anterior tibial, posterior tibial, and even peroneal vessels. We do all kinds of atherectomy and percutaneous transluminal angioplasty and stenting. We have done mechanical thrombectomy. Use of ultrasound in order to have a good pedal access is key. Certainly, going transpedal is not a skill set you can achieve overnight, but it is very feasible to gain that skill set over time, similar to how many operators have moved to a transradial approach for coronary procedures. 

Disclosure: Dr. Ali reports no conflicts of interest regarding the content herein.

Dr. Farhan Ali can be contacted at f.ali@hcnt.org.