Device Trial Participant Snapshot: Esprit BTK Everolimus Eluting Resorbable Scaffold System
Device Category: Cardiovascular
Summary:
What is this device used for?
The Esprit BTK Everolimus Eluting Resorbable Scaffold System is a stent and catheter system (an expandable mesh coil inserted with a flexible tube) used to help open arteries in the leg below the knee. It's mainly for adults who have peripheral arterial disease (narrowing arteries) and are at risk of needing an amputation due to lack of blood flow to their leg or foot. The stent contains a drug (everolimus) meant to help prevent the artery from becoming blocked again.
How is the device used?
The doctor uses the catheter tube to place the stent in the artery during an angioplasty procedure. The procedure involves guiding the system through a blood vessel to the location where the artery is narrowing. A balloon on the catheter inflates to open the artery and expand the stent to keep it in place where it will help the artery stay open. The stent is temporary and dissolves after the artery heals over it.
What are the benefits of this device?
In the clinical study, patients treated with the Esprit BTK were more likely to have their arteries remain open compared to those treated with PTA.
What are the risks and potential harmful side effects of this device?
The main risks are related to the angioplasty procedure used to place the device in the artery. The area where the system is inserted may bleed, bruise, or become infected. The artery being treated may become damaged during the procedure, which could cause bleeding or worsened blood flow. If the stent becomes damaged or isn’t placed correctly, additional medical procedures may be needed to fix it.
Demographics Snapshot:
Figure 1. Participant Demographics by Sex
Figure 2. Participant Demographics by Race
Figure 3. Participant Demographics by Ethnicity
Table 1: Participant Demographics
| Category | Average | Range |
|---|---|---|
| Age (years) | 72.5 | 47-94 |
| Number of Participants | Percentage (%) | |
| Sex | ||
| Male | 178 | 68% |
| Female | 83 | 32% |
| Race | ||
| American Indian or Alaskan Native | 1 | 0.4% |
| Asian | 47 | 18% |
| Black or African American | 32 | 12% |
| Native Hawaiian or Pacific Islander | 3 | 1% |
| White | 154 | 59% |
| Unknown | 25 | 10% |
| Ethnicity | ||
| Hispanic or Latino | 43 | 16.5% |
| Non-Hispanic or Latino | 202 | 77.4% |
| Unknown | 16 | 6.1% |
Who participated in the clinical trial studies?
The clinical study included adult patients that had pain in their leg even when not walking or unhealing wounds to the skin caused by lack of blood flow. The trial helped determine if the product was safe and effective. For more information about the demographics of all participants, please see Table 1.
What did the trials evaluate?
Patients underwent an angioplasty procedure either with the Esprit BTK or without a stent (called percutaneous transluminal angioplasty, or PTA). Safety was measured by comparing over time how many patients in each group died, needed an amputation above the ankle, or had another major procedure on the same leg. Effectiveness was measured by comparing how many patients in each group kept their leg and kept their artery open after one year.
Were there any differences in how well the device worked in clinical trials among sexes, races, ethnicities, and age groups?
No important differences were seen between male and female participants in the clinical trial. Arteries were kept open and no above the ankle amputations were needed for 73% of male participants and 77% of female participants one year after being treated with the Esprit BTK.
The Esprit BTK was more effective than PTA in every racial and ethnic group included in the trial. The data showed a bigger advantage of the Esprit BTK over PTA in Black or African American patients than in White patients, but this could be due to random chance.
The data showed a bigger advantage of the Esprit BTK over PTA in patients 65 years and older than in patients younger than 65, but this could also be due to random chance.
Were there any differences in risks among sex, race, and age groups?
After receiving the device, no female participants and few (5%) male participants experienced any of the serious problems the trial was designed to study. Two male participants had an amputation above the ankle within 6 months of treatment, one male participant had a major additional procedure on his leg within 6 months, and two male participants died within 30 days. None of these problems occurred with female participants. There were more male participants in the trial, and it is likely that this difference was due to random chance. There is also no evidence that the Esprit BTK caused these events to happen.
Three of the five patients that had one of the events described above were of Hispanic or Latino ethnicity. All five described their race as White. There isn’t enough information to know if Hispanic or Latino patients have a real difference in risk compared to non-Hispanic or Latino patients.
Patients 65 and older were equally as likely as patients younger than 65 to have a safety event.
Summary for Clinical Audiences
The clinical study was a randomized controlled trial that enrolled 261 participants in a 2:1 ratio for Esprit BTK or PTA. The primary safety endpoint was freedom from major adverse limb events at six months and peri-operative death at 30 days. Esprit BTK was shown to be non-inferior to PTA for this endpoint (97% vs. 100%, respectively). The primary effectiveness endpoint was the composite rate of primary patency and limb salvage at one year. Esprit BTK was superior to PTA for this endpoint (74.5% vs. 43.7%, respectively). A post approval study will examine device performance under commercial use, which is expected to include a more heterogeneous patient population.