The MANTA vascular closure device in transfemoral TAVI: a real-world cohort

INTRODUCTION

Transcatheter aortic valve implantation (TAVI) is an established treatment option for patients with severe symptomatic aortic stenosis,1 especially those at high surgical risk2 (also those at low and intermediate risk), and is often performed via transfemoral access route (TF-TAVI).1 However, TF-TAVI access requires large-bore catheters (5 mm to 7 mm) and their management is responsible for a significant number of TAVI-related adverse events. Complications can affect between 5% and 20% of the patients,3 and impact short- and long-term clinical outcomes.3-5 Therefore, successful closure of large-bore access sites remains essential.6,7

During the early years of TF-TAVI, the femoral artery was closed surgically.2 More recently, this method has been replaced by the use of suture-based vascular closure devices (VCD)1 like the Perclose ProGlide VCD (Abbott Vascular, United States).1,8 Although this closure technique proved to be a safe and effective first-line strategy for large-bore arterial access,1 major vascular complications occurred in up to 5% of patients mainly due to failed arteriotomy closure devices.

MANTA (Teleflex/Essential Medical, United States) is a plug-based VCD that has shown promising results in TF-TAVI.29-14 This device is dedicated to large-bore vessel closure and built on a proven concept of an intra-arterial toggle and extra-arterial collagen plug.5,15 Early feasibility trials have reported encouraging safety and efficacy outcomes in a variety of procedures requiring large-bore vascular access.1,9,11,16 Also, registry-based studies have demonstrated equivalence to suture-based techniques.1,17 However, data regarding vascular complications and device failure rates compared to the well-known suture-based VCDs are scarce.2 Recent studies, including small, selected patient cohorts concluded that compared to suture-based VCDs, plug-based VCDs were associated with significantly shorter lengths of stay following the procedure,1,7 and less VCD failure.1,5,7 No significant differences regarding mortality, bleeding or vascular complications were ever reported.7

This single-center study aims to investigate the safety and effectiveness of the MANTA VCD in patients undergoing TF-TAVI in an unselected and consecutive cohort of patients. We hypothesize that arterial closure with MANTA is associated with a high feasibility and low risk of major vascular and bleeding complications.

METHODS

Study design

This single-center observational, and retrospective study included a total of 245 consecutive patients who underwent TF-TAVI and in whom the MANTA device was used to close the arterial large-bore femoral access from March 2020 through February 2022 (figure 1). All patients had symptomatic severe aortic stenosis. Eligibility for TF-TAVI procedure was assessed by the heart team. The study was approved by the regional Human Research Ethics Committee (HREC) at Coimbra, Portugal. Informed consent was waived. Demographics, preoperative, intraoperative, and postoperative data were collected from medical records.

Figure 1. Central illustration. Flowchart of the patients incuded. TAVI, transcatheter aortic valve implantation; TF-TAVI, transfemoral transcatheter aortic valve implantation.

Study outcomes

The study primary efficacy outcome measure was the rate of device failure according to the Valve Academic Research Consortium 3 (VARC-3) definition.18 Device failure was defined as failure to successfully achieve hemostasis at the access site, thus leading to alternative treatment (surgery, balloon or covered stent).

The study secondary outcome was safety. Here we assessed the rate of VARC-3 major vascular and bleeding complications associated with the access site. Major vascular complications are lesions (perforations, ruptures, dissections, stenoses, ischemias, arterial thromboses, arteriovenous fistulas, pseudoaneurysms, hematomas, retroperitoneal hematomas, infections) resulting in death, VARC type ≥ 2 bleeding, limb or visceral ischemia or irreversible neurological impairment; distal embolization (noncerebral) from a vascular source resulting in death, amputation, limb or visceral ischemia or irreversible end-organ damage; unplanned endovascular or surgical intervention resulting in death, VARC type ≥ 2 bleeding, limb or visceral ischemia or irreversible neurological impairment. A major bleeding is considered type 2 if an overt bleeding requires the transfusion of 2–4 units of whole blood/red blood cells or else in the presence of an overt bleeding associated with a drop of hemoglobin levels from 3 g/dL to 5 g/dL; type 3 if bleeding is life-threatening, and type 4 if it leads to death.

As exploratory endpoints, we also evaluated cardiovascular and non-cardiac mortality during the index hospitalization and at 30-day follow-up.

Procedural details

Before TF-TAVI, all patients underwent an echocardiogram, blood tests, and a multi-detector computed tomography according to the TAVI protocol using a dedicated software (3mensio, Maastricht, The Netherlands). Multi-detector computed tomography was performed to assess iliofemoral arteries for vascular access prior to the procedure. The size of the vessel, tortuosity, amount of calcification, and minimal lumen diameter were all analyzed. Calcification and tortuosity were separately scored by consensus visual analysis of 2 observers who were blind to the remaining patient data. The sheath-to-femoral artery diameter ratios were analyzed too. Anticoagulant and antiplatelet therapies according to the guidelines: if the patient was on anticoagulation, he didn’t use the anticoagulant the day before and resumed it on the day of the procedure (in the absence of bleeding complications); if on antiplatelet therapy, single antiplatelet therapy was used; if not on anticoagulant or antiplatelet agent, an aspirin loading dose was used before the procedure followed by a single antiplatelet therapy agent. All procedures were performed under conscious sedation. Puncture of the femoral artery was performed with ultrasound guidance. During the procedure, heparin was administered and an activated clotting time between 250 s and 300 s was targeted. The bioprosthetic valves implanted were the CoreValve Evolut R/Pro (Medtronic, United States), ACURATE neo (Boston Scientific, United States), SAPIEN (Edwards Lifesciences, United States), and Navitor (Abbott, United States). After valve implantation, in cases where the activated clotting time was > 200 s, protamine sulfate was given before vascular closure.

MANTA device

The MANTA VCD is a collagen-based technology available in 2 sizes: 14-Fr and 18-Fr. It can be used for sheath sizes that go from 10-Fr to 14-Fr, and 15-Fr to 22-Fr, respectively. In brief, arteriotomy depth is determined with a centimeter-marked sizing tool before large-bore sheath insertion. At the end of the procedure, the large-bore sheath is exchanged for the dedicated MANTA sheath to accomodate the toggle–plug assembly. Afterwards, the anchor is opened 1.5 cm more than the femoral arterial wall-skin distance. The sheath is then removed, and the puncture site sandwiched between toggle and collagen that remain connected by a stainless-steel lock. Hemostasis success after the use of the MANTA VCD was evaluated through an angiography after vascular closure. As a standard practice, we typically use the contralateral femoral artery as a backup access, but do not routinely use a protection guide. In situations where access to the main site is necessary, we use a 0.035 in Glidewire Advantage guidewire that is advanced through the pigtail situated in the contralateral femoral artery and placed under the balloon. In the presence of bleeding complications that are not resolved by prolonged balloon inflation, a covered stent is often implanted.

Statistical analysis

Continuous variables are expressed as mean ± standard deviation if normally distributed or as median [interquartile range] if not. Normality was checked using the Shapiro–Wilk test and histogram observation. Categorical data were expressed as numbers and percentages and compared using Pearson’s chi-square test or Fisher’s exact test, when appropriate. Continuous variables were compared using the Student t test. Formal tests for interaction were performed using logistic regression. Statistical significance was always set at a 2-tailed probability level of < 0.05. Statistics were performed using SPSS version 28 (IBM, United States).

RESULTS

Baseline characteristics

A total of 245 of consecutive patients treated with TF-TAVI whose arterial large-bore femoral access was closed with the MANTA 18-Fr VCD were included in our study. The baseline characteristics are shown on table 1. The population mean age was 81 ± 6 years with a median EuroSCORE II of 3.15% [2.07%-4.75%]. Most patients were women (53.9%). The Evolut R/Pro valve was implanted in > 50% of the cases (52.7%).

Table 1. Baseline characteristics

Primary outcome: efficacy of the MANTA plug-based vascular closure device

Successful closure of the large-bore access site occurred in 92.2% of the patients (n = 226). The main access artery was the right common femoral one in 90.6% of the patients (n = 222). The mean minimal femoral arterial diameter at the access site was 7.5 ± 1.4 mm (table 1). The mean sheath-to-femoral artery diameter ratio was 0.69 ± 0.15 (table 2). Only 1 out of the 19 patients with device failure (7.8%) required a secondary surgical approach (due to occlusion of the femoral artery unresolved with balloon dilatation) (table 3).

Table 2. Procedural characteristics

Table 3. Primary endpoint – efficacy

Secondary outcome: safety of the MANTA plug-based vascular closure device

According to the VARC-3 definition, no major vascular or bleeding complications associated with the plug-based device were reported. A total of 8.6% of all the patients included (n = 21) had a minor VARC-3 vascular complication (table 4). Two-thirds (n = 14) showed femoral artery stenoses, 23.8% (n = 5) hematomas, and 9.5% (n = 2) pseudoaneurysms associated with the common femoral artery. The rate of minor bleeding complications associated with the main access site (closed with MANTA) was 2.9% only (n = 7).

Table 4. Secondary outcome: safety

Predictors of device failure

Patients with device failure (7.8%) had a significant smaller minimal femoral artery diameter (6.6 ± 1.1 mm vs 7.6 ± 1.4 mm; P = .005) and consequently, significant higher sheath-to-femoral artery diameter ratios (0.78 ± 0.16 vs 0.69 ± 0.15; P = .019) (table 5>). Patients with failed VCDs had more tortuous and calcified arterial accesses as shown on table 5. No other differences were found.

Table 5. Failed device vs non-failed device

In-hospital and short-term outcomes

Duringt the index hospitalization, 2 patients (0.8%) died of cardiovascular causes not associated with the VCD closure. One patient died due to aortic dissection and left ventricular rupture during the procedure despite conversion to open heart surgery. A second patient died following an ischemic stroke. The 30-day mortality rate was 3/245 (1.2%) because another patient died of urosepsis 14 days after discharge. Device failure did not extend the postoperative length of stay (median time to discharge, 4 days [3-5]).

DISCUSSION

This single-center study shows the real-world experience with the MANTA VCD for large caliber arteriotomy closure in an unselected consecutive cohort of patients referred for TF-TAVI. Our results, in an older and more frail population compared to RCT1,5 [with a EuroSCORE II of 3.15% (2.07-4.75), higher than the 2.6% (1.9-3.6) of the MASH trial, but lower than the 4.5 ± 4.8% of the CHOICE-CLOSURE] demonstrate a low MANTA device failure rate of 7.8% with no major device-related bleeding or vascular complications.

Compared to the most recent RCTs (MASH5 and CHOISE-CLOSURE1 trials) that included 216 and 510 patients, respectively, our results showed a lower rate of device failure with the MANTA device compared to the MASH trial (7.8% vs 20%), but > 4.7% compared to the CHOISE-CLOSURE,1,5 and 5.2% in a recent metanalysis.19 However, in the latter trial, authors did not consider balloon dilatation bailout as device failure, which may explain the lower failure rate of the plug-based VCD while we used balloon dilatation in most devices failures (16 out of 19 failures).

The high success rate of the MANTA device (92.2%) is probably due to our extensive experience with this type of device. Since the beginning of the TAVI program, this has been the most widely used VCD, which differentiates us from former studies. Furthermore, all TF-TAVIs were performed by a small group of 3 experienced operators with a large volume of vascular closure cases using this device. Conversely, in the MASH trial, MANTA was introduced later in the clinical practice and, consequently, experience was more limited.5 Compared to suture-based large-bore arteriotomy closure, the MANTA device showed less device failure and shorter time to hemostasis in both trials.1,5

We did not report any major vascular or bleeding complications associated with the MANTA VCD unlike RCTs1,5 and the most recent observational study. Still, this last study used VARC-2 criteria to define major complications.20 Halim et al.2 showed rates of minor vascular and bleeding complications of 13.7% and 5.5%, respectively, almost doubling those of our cohort (8.6% and 2.9%, respectively). As previously mentioned, this may be explained by our experience with this VCD. Another possible reason was that we were used to smaller plug-based devices like Angioseal.1,9,16 Therefore, familiarity with this technique seems to facilitate short learning curves with the MANTA device.1,13,14

In the MASH and CHOISE-CLOSURE trials, patients whose large-bore arterial access site were closed with the MANTA device had more minor vascular and hemorrhagic complications compared to those whose access sites were closed with suture-based devices. However, they were not significatively different and no differences in major complications were ever reported. This fact can be explained by the greater knowledge and experience using the ProGlide VCD by these teams.1,5 In a meta-analysis that compared MANTA vs suture-based VCD7 the authors conclude that plug-based vascular closure with MANTA was associated with fewer chances of device failure following large-bore arteriotomy procedures without significant differences being reported in bleeding or vascular complications compared to suture-based closure devices.

Although recommendations21 tell us that we should not use the MANTA device in vessels with minimum diameters < 6 mm, some of our patients had lower values. The main reason observed for VCD-related adverse vascular events was common femoral artery stenosis due to poor toggle positioning in smaller femoral arteries. This has been previously reported in the medical literature.22 Therefore, the implantation of MANTA in smaller femoral arteries should be avoided. Thus, as expected, those with device failure had a significantly smaller minimal femoral diameter, higher sheath-to-femoral artery diameter ratios, and more tortuous and calcified arterial accesses.

A recent study23 showed that when ultrasound was used to guide MANTA implantation, fewer vascular complications and device failure were reported perhaps because ultrasound helps clinicians choose the best site, thus avoiding calcium plaques and confirming the anchor in the proper position and the collagen pad delivered to the vessel wall through subcutaneous tissue. We had already used ultrasound to guide femoral access, which may explain our low rate of vascular complications. However, if in the future we also guide the deployment of MANTA, it can be possible to further reduce device failure not associated with postoperative length of stay or mortality as in former studies.1,5,7 We had a lower rate of in-hospital mortality (0.8%) compared to the 1.5% of the CHOICE-CLOSURE trial. No deaths were associated with the MANTA device.1,5

As far as we know, this is the largest real-world study ever conducted using MANTA to close large-bore femoral arterial accesses after TF-TAVI whose primary outcome was device efficacy using the VARC-3 criteria. The MANTA device shows promising results with low rates of vascular/bleeding complications and device failure without compromising the length of stay or the in-hospital/short-term mortality in the real-world setting. The shorter learning curve compared to suture-based VCDs is another plus. Therefore, the MANTA device could become the preferred option for large-bore vascular closure in TF-TAVI. The ultrasound-guided implantation of MANTA seems to be a solution for the complications and device failure seen in these patients. Thus, futures studies must compare the efficacy and safety profile of suture-based VCDs and ultrasound-guided plug-based VCDs in the real-world setting.

Limitations

This was a retrospective study and a single-center experience where we did not compare the plug-based VCD to another closure system. Therefore, it may be subject to different biases. Finally, our study did not perform postoperative ultrasounds in all patients. Therefore, we could have left out the asymptomatic vascular complications despite the angiographies performed after the procedure. However, no clinical impact was seen at follow-up of the putative asymptomatic vascular complications.

CONCLUSIONS

In this single-center, real-world, unselected and consecutive large cohort of patients treated with TF-TAVI, a plug-based VCD for large-bore arteriotomy closure turned out effective and safe, and enabled arterial access-site management with a low rate of complications. Smaller minimal femoral artery diameters and higher sheath-to-femoral artery diameter ratios were associated with a higher risk of failed VCDs.

FUNDING

None whatsoever.

ETHICAL CONSIDERATIONS

The study was approved by the regional Human Research Ethics Committee (HREC) at Coimbra, Portugal. Informed consent was waived. The authors confirm that variables such as sex and gender were taken into account in accordance with SAGER guidelines.

STATEMENT ON THE USE OF ARTIFICIAL INTELLIGENCE

Artificial intelligence was not used for the development of this work.

AUTHORS’ CONTRIBUTIONS

Study design, data collection and review, statistical analysis, and manuscript preparation: S. Martinho, E. Jorge, A. Vera Marinho, R. Baptista, M. Costa, and L. Gonçalves; Coordination and document submission: S. Martinho. All authors reviewed and approved the final version of the manuscript.

CONFLICTS OF INTEREST

None reported.

REFERENCES