Sponsored by AccessClosure, Inc.

Mynx Vascular Closure Device Early Ambulation Study

The safety and benefits of 1-hour ambulation with the Mynx 5-F Vascular Closure Device.

By Vikranth R. Gongidi, DO; Ahsan Jafir, DO; and Vijay Verma, MD, FACC, FSCAI
 

Vascular closure devices (VCDs) are increasingly used for femoral access closure in cardiac catheterization, in large part because they allow for early ambulation after the procedure. The benefits of early ambulation include improved hospital throughput and earlier dischargeability, resulting in cost savings. In some cases, this early discharge can convert a potential inpatient procedure to an outpatient case. Early ambulation also can improve patient comfort, especially for those with comorbidities (eg, obesity, back pain, etc.) for whom extended time lying flat can be quite painful.

Early ambulation is of particular value for patients undergoing diagnostic procedures. The risk of vascular complications from diagnostic cardiac catheterization is relatively low, ranging from 0.4% to 3%,1,2 and diagnostic procedures are less likely to involve heavy use of anticoagulants. Clinicians routinely perform diagnostic procedures entirely with 5-F catheters to minimize trauma to the vessel and reduce the risk of complications. Select VCDs, including the Mynx Vascular Closure Device (AccessClosure, Inc., Santa Clara, CA) (Figure 1), allow closure through an existing 5-F procedural sheath. The aim of the present study was to assess the safety and feasibility of early ambulation in patients undergoing diagnostic procedures utilizing a 5-F introducer sheath and compare outcomes to those in patients undergoing procedures with a 6-F sheath.

TECHNOLOGY OVERVIEW

The Mynx VCD is designed to achieve femoral artery hemostasis via delivery of an extravascular, watersoluble synthetic sealant using a balloon catheter in conjunction with the existing procedural sheath. The sealant is made of a polyethylene glycol material that expands upon contact with blood and subcutaneous fluids to seal the arteriotomy (Figure 2). The sealant is resorbed by the body within 30 days.

The Mynx received US Food and Drug Administration approval in May 2007. The original clinical study performed on the Mynx 6/7-F VCD has been described by Scheinert et al.3 The Mynx VCD is indicated to seal femoral arterial access sites while reducing time to hemostasis and ambulation in patients who have undergone diagnostic or interventional endovascular procedures using a 5-, 6-, or 7-F procedural sheath.4

Procedures using 5-F sheaths for diagnostic coronary and peripheral catheterization are now common. These smaller sheaths decrease damage to the artery and reduce complications. However, many commercial VCDs require procedure sheath exchanges and upsizing to enable deployment of the closure implant. The 5-F Mynx (approved in 2009) was designed to eliminate the need for sheath exchange, as it can be deployed through the existing 5-F procedural sheath. This prevents the need to enlarge the arterial hole or traumatize the surrounding tissue.

THE MYNX EARLY AMBULATION STUDY

At the New Jersey Heart Institute, Our Lady of Lourdes Medical Center, we examined clinical outcomes of patients receiving the 5-F Mynx VCD in a single-center, postmarket setting, and ambulating at 1 hour after VCD deployment.

This single-center, prospective study enrolled patients undergoing percutaneous diagnostic procedures using a 5-F procedural sheath in the common femoral artery and arteriotomy closure with a 5-F Mynx VCD. The study was approved by the Institutional Review Board, and written informed consent was obtained from patients before enrollment. Primary and secondary endpoints included the number of major complications at 30 ± 7 days, device success, time to ambulation, time to discharge, and minor complications.

This study was intended to demonstrate noninferiority of the 5-F Mynx VCD when ambulating patients at 1 hour to the historical safety of the 6/7-F Mynx VCD as reported by Scheinert et al3 and in the regulatory filing of the Mynx VCD. 4A sample size of 160 patients was required (alpha = 0.05, 90% power) to test the study hypothesis (nQuery Advisor, version 7.0; Statistical Solutions, Saugus, MA). Two hundred patients were enrolled in the study to account for any patients that were withdrawn or lost to follow-up. All statistical analyses were performed with statistical analysis software (version 9.2 SAS Institute, Cary, NC).

METHODS

All patients underwent diagnostic angiography according to standard practice. At the end of the procedure, angiography of the access site was performed. If the puncture site was deemed appropriate based on the iliofemoral angiogram, the Mynx VCD was deployed per the manufacturer's instructions. After closure, the access site was assessed for hemostasis. Device success was defined as successful deployment of the Mynx device and hemostasis achieved with no more than 10 minutes of manual compression. Patients were ambulated 1 hour after Mynx deployment, and the time to ambulation and dischargeability were recorded. Patients were assessed for complications postprocedure, at ambulation, and at discharge and were contacted via telephone at 30 ± 7 days to assess any late complications. Any patients seeking medical attention after the procedure for access site– or procedure related concerns received ultrasound evaluation of the access site. All adverse events had independent adjudication of complication classification.

RESULTS

Two hundred patients were enrolled in the study from April 2010 to March 2011. All deployments (100%) were successful, and there were no device failures. One major (0.5%) complication (requiring an endovascular procedure) occurred within 30 days. No minor complications occurred. The average time to ambulation after deployment was 1.03 hours. The average time to dischargeability was 1.9 hours (Table 1).

Comparison to Historical Data

In the original Mynx clinical study by Scheinert et al,3 the 6/7-F Mynx VCD was studied in both diagnostic (n = 95) and interventional (n = 95) patients, and detailed clinical data are available in the Mynx device Instructions for Use document. 4The time to ambulation was similar for both arms (mean, 2.5 ± 2.1 vs 2.8 ± 3 h).4 This was a significant improvement over both manual compression control arms, for which the time to ambulation was 5.4 ± 2.7 hours for diagnostic patients (n = 82) and 9.4 ± 5.6 hours (n = 78) for interventional patients.4 Safety and efficacy endpoints with the Mynx VCD were similar for both patient populations as well: major complications were observed in 0% of diagnostic patients and 1.1% of interventional patients, whereas minor complications were observed in 3.2% and 4.2%, respectively.4

This study evaluated the 5-F Mynx device in diagnostic patients with the goal of comparing these results to the diagnostic arm of the original Mynx study. Per protocol, ambulation was required at 1 hour, and as a result, the mean time to ambulation in our study was less than half of that in the original Mynx study (1.03 ± 0.16 vs 2.5 ± 2.1 h).4 The major complication rate was comparable (0.5% vs 0%) to the diagnostic arm in the original Mynx study4 and remained within the acceptable complication rate of < 1% for low-risk diagnostic angiographic procedures as recommended by the American Heart Association scientific statement on arteriotomy closure devices.5 The minor complication rate improved from 3.2% in the diagnostic arm of the original study3 to 0% in our study.

Patient Characteristics

The baseline patient characteristics are described in Table 2. The average age was 59 years, sexes were evenly divided at 50%, and the average body mass index was 30.2. There were 59/200 patients (29.5%) with a history of ipsilateral femoral access or closure device. A majority of the patients had hypertension (74.5%) and hypercholesterolemia (74.5%). There were a small number of patients with a history of diabetes mellitus (23.5%), cerebrovascular accident or transient ischemic attack (5.5%), and peripheral vascular disease (3.5%). A majority of the patients were outpatient (98.5%). See the Inclusion and Exclusion Criteria sidebar for an overview of how these factors applied in this study.

Procedural Characteristics

Table 3 summarizes the procedural characteristics. International normalized ratios were available in 79 patients (39.5%) and averaged 1 ± 0.11. During the procedure, aspirin was used in one patient (0.5%, N = 1/200), and heparin was used in two patients (1%, N = 2/200). No patients received warfarin, enoxaparin, bivalirudin, clopidogrel, or dypridamole during the procedure. The average blood pressure was 133 ± 18 mm Hg systolic

Complications

See the Definitions of Major and Minor Complications sidebar for an overview of how these were defined in this study. Postprocedure, 15 patients sought medical attention for access site– or procedure-related concerns, of which only one patient met the criteria for major or minor complications. One major complication was noted in one patient (0.5%), who presented at another institution with groin pain. The ultrasound could not rule out thrombus in the femoral artery, and the patient underwent thrombectomy with infusion of lytics. No minor complications occurred (Table 4).

DISCUSSION

This study shows that the Mynx 5-F VCD is a safe choice for patients undergoing diagnostic procedures and demonstrates that early ambulation at approximately 1 hour after deployment is feasible and safe for this low-risk patient population.

The low complication rate observed with the Mynx VCD may be attributed to several factors. Procedural factors, such as the use of small sheaths (5 F) and the lack of anticoagulation, may have contributed to the safe nature of the closure procedure. Device factors favorably affecting outcomes include the compatibility of the Mynx VCD with existing procedure sheath (ie, nonrequirement of sheath exchanges and associated arteriotomy manipulations). Although the only complication observed in this study resulted in a requirement for intervention, this type of complication has been shown to occur significantly less often with Mynx (0.06%) versus other closure devices (0.61% in Angio-Seal [St. Jude Medical, Inc., St. Paul, MN]; P < .0001), or manual compression (0.19%; P = NS).6

In addition to reductions in discomfort associated with early ambulation, the Mynx VCD has been shown to provide improved patient comfort and is particularly valuable to patients undergoing diagnostic procedures, which often require minimal sedation. Fargen et al reported significantly reduced pain at closure with the Mynx device as compared to Angio-Seal (P = .009) in a blinded, randomized controlled study.7

Study Limitations

The current study compares closure outcomes in diagnostic procedures utilizing 5-F introducer sheaths to historical data available from diagnostic procedures utilizing 6/7-F sheaths. The impact of sheath size has been shown to be a direct predictor of closure outcomes.8 The relatively small sheath size in the present study may have offset the complication risk arising from early (1-h) ambulation and could explain the difference in minor complications seen in the present study (0%) versus historical data (3.2%).

CONCLUSION

In this single-center study investigating the use of the Mynx VCD in patients undergoing diagnostic procedures, early (1-h) ambulation was feasible. Only one major complication and no minor complication events were observed. This was comparable to historical safety data available on the Mynx device.

We acknowledge Nancy Markiewicz and Julie Bettelli for their assistance on this project. We would also like to thank the AccessClosure team for their assistance in the preparation and submission of the manuscript.

Vikranth R. Gongidi, DO, is affiliated with Our Lady of Lourdes Medical Center in Camden, New Jersey. He has disclosed that he holds no financial interests in any of the products or manufacturers mentioned in this article. Dr. Gongidi may be reached atvgongidi@yahoo.com.

Ahsan Jafir, DO, is affiliated with Our Lady of Lourdes Medical Center in Camden, New Jersey. He has disclosed that he holds no financial interests in any of the products or manufacturers mentioned in this article. Dr. Jafir may be reached atajafir@gmail.com.

Vijay Verma, MD, FACC, FSCAI, is affiliated with Cardiovascular Associates of the Delaware Valley, Pennsylvania, and the New Jersey Heart Institute at Our Lady of Lourdes Medical Center in Camden, New Jersey. He has disclosed that he holds no financial interests in any of the products or manufacturers mentioned in this article. Dr. Verma may be reached atvkvmd72@gmail.com.

Disclosure Statement:

The authors disclose that a partial research grant provided by AccessClosure, Inc. was used to support this study.

AccessClosure and Mynx are trademarks of AccessClosure, Inc., registered in the US Patent and Trademark Office.

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  2. Pepine CJ, Allen HD, Bashore TM, et al. ACC/AHA guidelines for cardiac catheterization and cardiac catheterization laboratories: American College of Cardiology/American Heart Association Ad Hoc Task Force on Cardiac Catheterization. Circulation. 1991;84:2213-2247.
  3. Scheinert D, Sievert H, Turco MA, et al. The safety and efficacy of an extravascular, water-soluble sealant for vascular closure: Initial clinical results for Mynx™. Catheter Cardiovasc Interv. 2007;70:627-633.
  4. Mynx™ Vascular Closure Device Instructions for Use. 2009 LBL 4112 Rev. R.
  5. Patel MR, Jneid H, Derdeyn CP, et al. Arteriotomy closure devices for cardiovascular procedures. Circulation. 2010;122:1882-1893.
  6. Noor S, Meyers S, Curl R. Successful reduction of surgeries secondary to arterial access site complications: a retrospective review at a single center with an extravascular closure device. Vasc Endovascular Surg. 2010;44:345-349.
  7. Fargen KM, Hoh BL, Mocco J. A prospective randomized single-blind trial of patient comfort following vessel closure: extravascular synthetic sealant closure provides less pain than a self-tightening suture vascular compression device. J NeuroIntervent Surg. 2011;3:219-223.
  8. Cantor WJ, Mahaffey KW, Huang Z, et al. Bleeding complications in patients with acute coronary syndrome undergoing early invasive management can be reduced with radial access, smaller sheath sizes, and timely sheath removal. Catheter Cardiovasc Interv. 2007;69:73-83.
 

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