Orbital Atherectomy of the Iliofemoral Arteries Facilitates Large-Bore Access Prior to Transfemoral Transcatheter Aortic Valve Replacement

Objectives. To describe the use of orbital atherectomy to prepare iliofemoral vessels for large-bore access prior to transcatheter aortic valve replacement (TAVR). Background. Transfemoral (TF)-TAVR has been shown to be at least equivalent to surgery. Nevertheless, many patients do not qualify for the TF approach due to severe iliofemoral occlusive disease. The use of an atherectomy device in order to facilitate TF-TAVR has only been reported in case reports. Methods. We performed 1000 TAVR procedures from June 2017 to October 2019. Patient demographics, procedural characteristics, computed tomography characteristics, and short-term outcomes were recorded. Hostile access was defined as luminal size <5 mm, or <5.5 mm along with the presence of >270° calcification. The primary endpoint was the ability to successfully deliver a transcatheter valve via the intended pretreated access site. Results. During the study period, 6 subjects (0.6%) required alternative access and 68 patients (6.8%) were considered to have a hostile iliofemoral anatomy that required vessel preparation prior to TAVR. Forty-eight patients (70.6%) had angioplasty only and 20 patients (29.4%) required atherectomy and angioplasty. Out of 20 patients treated with atherectomy, successful TF delivery of the valve was achieved in 19 patients (95%). There was no in-hospital mortality or stroke. There were no perforations. One subject required placement of a self-expandable stent due to severe dissection. Conclusion. Orbital atherectomy used for vessel preparation is a safe and very effective technique to facilitate TF-TAVR in patients with hostile peripheral anatomy.

J INVASIVE CARDIOL 2021 July 14 (Ahead of Issue). 

Key words: hostile femoral access, orbital atherectomy, TAVR

Transcatheter aortic valve replacement (TAVR) has proven to be non-inferior to surgical aortic valve replacement (SAVR) for patients at low, intermediate, or high risk for surgical replacement.¹ Transfemoral (TF) access is the most common approach for TAVR. TF-TAVR was shown to improve outcomes when compared with both SAVR as well as TAVR performed via transapical approach.^2,3 Current guidelines suggest that SAVR should be reconsidered when TF access is not possible.⁴ Despite the significant downsizing of current device profiles, TF-TAVR is only performed in 80%-85% of all TAVR procedures.⁵ The most common reason for avoiding or aborting TF-TAVR access is the presence of severe calcified iliofemoral arteriopathy. The ability to pretreat iliofemoral vessels with angioplasty only in order to optimize large-bore access has been shown to allow transfemoral TAVR in the great majority of cases.⁶ However, in severely calcified vessels, a balloon angioplasty only approach may not suffice and atherectomy may be needed.

The Diamondback (DB) Orbital Atherectomy System (OAS) (Cardiovascular Systems, Inc [CSI]) is an atherectomy device specifically designed to treat calcified arteries. This manuscript describes our experience using DB 360 as the atherectomy device of choice when preparing iliac and femoral vessels for large-bore access in a group of patients deemed to have an otherwise hostile calcified femoral access. 

Study population. We reviewed our database for the last 1000 TAVR procedures. Computed tomography (CT) scans to evaluate peripheral access were available for all cases. The subjects who met the following criteria were considered to have hostile access for TF-TAVR and were included in the study: minimal lumen diameter (MLD) <5 mm or MLD <5.5 mm along with >270° arc of calcification.⁶ Tortuosity >120° in a calcified segment was the only exclusion criteria. Demographic data and procedure-specific data were collected in a prospective fashion. These included the type of peripheral procedure performed, anatomic characteristics, the type of access, additional procedures performed in order to facilitate access, type of atherectomy devices used, contrast volume, fluoroscopy time, procedural time, hospital length of stay, and perioperative complications up to 30 days.

Endpoints. The primary endpoint of the study was the successful completion of TAVR via the intended TF access after the iliofemoral vessels were treated with OA. The secondary feasibility endpoint was the ability of OA to facilitate full balloon expansion of the lesion. The secondary safety endpoints were procedural complications as defined by the Valve Academic Research Consortium (VARC)-2 criteria. Other secondary outcomes included in-hospital outcomes, all-cause mortality, stroke, myocardial infarction (MI), bleeding, and major vascular complications. The vascular complications recorded were vessel perforation, flow-limiting dissection, distal embolization, and access-site hematoma. In cases where the OA procedure preceded the TF-TAVR procedure, safety endpoints were recorded separately for each procedure. 

CT review. All CT scans were analyzed using a dedicated workstation (3Mensio Valves Software, Pie Medical Imaging) at the interventional site from the common femoral artery (CFA) to the distal aorta. The following measurements were obtained: minimal lumen diameter (MLD); maximum luminal diameter; vessel area at the site of the most severe narrowing; degree of vessel calcification; and tortuosity. The mean lumen diameter was computed as the average vessel diameter (maximal + minimal diameter/2), measured at the MLD. Calcification was defined as severe if an arch >270° was present (Figure 1). 

Iliofemoral vessel preparation for large-bore access protocol. Left or right radial access was obtained with a 6 Fr (5 Fr outer diameter) radial sheath. Femoral access was allowed only when radial access was deemed impossible (bilateral radial arteries harvested, occluded radial arteries from prior use, occlusion in the proximal upper-extremity vessels diagnosed on CT, small radials, accessory arteries). Next, a 0.035˝ wire was directed to the descending aorta and the short sheath was replaced with a 119 cm-long, 6 Fr (5 Fr outer diameter) Destination sheath (Terumo). After selective angiogram was performed, the iliac artery was wired with a 0.014˝ ViperWire (CSI) and atherectomy was performed with a 2.0 mm crown. A minimum of 4-6 runs per vessel was required. Next, the wire was pulled in the distal aorta and reoriented toward the contralateral iliac artery. Atherectomy was performed in the contralateral vessel following the same protocol. The atherectomy device was then removed, and angioplasty was performed with a 5.0 or 6.0 mm balloon. The balloon was inflated until full expansion was documented on fluoroscopy. If there was residual balloon indentation, there was an option to perform further atherectomy. Once lack of flow-limiting dissection was documented, the wire was again pulled into the distal aorta and reoriented toward the first treated lower extremity; the same balloon inflation protocol was used. Stenting was not allowed unless a flow-limiting dissection was still present after multiple prolonged balloon inflations. The atherectomy and angioplasty techniques are demonstrated in Video 1. 

Second-stage TF-TAVR protocol. The second stage of the procedure involved a classical TF-TAVR protocol, as previously described.⁶ Briefly, contralateral access was achieved with a 7 Fr sheath, and an 0.018˝ wire was positioned down the access-site limb. Next, femoral arterial access was obtained and 2 Perclose devices (Abbott Vascular) were deployed in preclose fashion. An 11 Fr Terumo sheath was placed in the CFA intended for TAVR device delivery. Angioplasty of the ipsilateral iliac artery (the same vessel previously treated with OA and angioplasty) was now performed with a 7.0 mm balloon. Next, the aortic valve was crossed and a stiff 0.035˝ wire with a ventricular loop was placed in the left ventricle. The 11 Fr sheath was removed, and the sheathless Evolut catheter valve (Medtronic) was advanced across the iliofemoral vessels and deployed in the aortic position. The integrity of the access site vessels was tested at the end of the procedure with selective angiograms from the contralateral access site. 

Between June 2017 and October 2019, a total of 1000 patients underwent TAVR at our institution. Heart team review deemed 68 patients (6.8%) to have hostile access. These patients underwent peripheral interventions in order to facilitate TF-TAVR; 48 (70.6%) underwent angioplasty only and 20 (29.4%) underwent OA and angioplasty. The demographics and CT characteristics of the patients who underwent vessel preparation with OA are shown in Table 1. Seventeen of the 20 interventions were done as a separate procedure prior to the index TAVR procedure. The median time from the day of iliac atherectomy to the TAVR procedure was 7 days (range, 2-24 days). Radial artery was the access site for the iliofemoral OA/angioplasty in 15 of the 17 cases. One case had both radials harvested for prior bypass, and 1 case had severe tortuosity on CT angiogram that precluded radial access. In 3 cases, the OA was done via TF approach at the time of TF-TAVR. All staged iliofemoral interventions were done as outpatient same-day discharge procedures. The procedural characteristics of the vessel preparation and index TF-TAVR are shown in Table 2. 

The primary endpoint of successful completion of TF-TAVR after vessel preparation using OA was achieved in 19 of the 20 cases (95%). The secondary efficacy endpoint of successful vessel preparation with OA was achieved in 19 of the 20 cases (95%). All cases with a successful vessel preparation led to successful TF-TAVR. The secondary safety endpoints are shown in Table 3. 

The current study reports the safety and efficacy of transradial OA and angioplasty in preparing severely diseased iliofemoral vessels for large-bore access during TF-TAVR. The following outcomes were observed: (1) radial access is safe, effective, and the preferred access site for these procedures; (2) OA safely and predictably prepares severely calcified iliofemoral vessels for full balloon expansion; (3) The 2-stage approach of vessel preparation followed by TF-TAVR is safe and reliably predicts successful TF-TAVR.

The radial artery is routinely used as an access site for diagnostic and interventional coronary procedures. Although the use of transradial peripheral interventions has been reported,⁷ this approach has not yet gained enough popularity. There are numerous reasons to use transradial access for endovascular iliofemoral interventions in general, and for vessel preparation for large-bore access in particular. First, this patient population has significant peripheral arterial disease frequently involving the common femoral arteries. Avoiding additional insult to this vascular bed is a sufficient reason to consider an alternative access site. Second, it was shown extensively that the use of radial artery significantly reduces access-site complications when compared with TF access.⁸ CFA complications prior to index TAVR procedure could lead to a further negative impact in the future TF-TAVR. Third, the transradial access allows easy treatment of both lower extremities during the same session, which is needed in many of these cases. 

The need for atherectomy as an adjunctive tool during vessel preparation is mostly determined by the extent and severity of the vessel calcification. The presence of Mockenberg medial calcinosis, especially when circumferential, could lead to poor angioplasty results. Using a calcium-dedicated atherectomy device may allow for a more uniform angioplasty result and minimize vessel barotrauma. In our review, only one-third of the subjects classified as hostile access required atherectomy. The decision to use atherectomy was based on our review of the CT scans, and selecting only cases with calcification involving >270° of the vessel circumference. The DB 360 OAS is our atherectomy device of choice when facing severely calcified iliofemoral vessels. The surface of the DB crown contains microdiamonds, which are designed to modify the surface of calcified plaque, releasing microparticles that are later engulfed by macrophages. The eccentric crown design allows for gradual orbiting, which leads to controlled plaque removal.⁹ Although the safety and efficacy of using OA in treating the superficial femoral artery and tibial vessels has been demonstrated in numerous studies,^10,11 the use of OA in the treatment of calcified iliac arteries has only been described in a few isolated reports.¹² Furthermore, we demonstrate for the first time the use of this technique via transradial approach in preparation for large-bore access. In our series, there were no complications associated with OA. The procedural time, (average duration of only 71 minutes), the low contrast use (average of 47 mL), and the same-day discharge in all cases add to the safety and efficiency of this procedure. The use of the device has allowed full balloon expansion in 19 of the 20 treated iliac arteries. The lack of balloon expansion in 1 case translated to inability to deliver the transcatheter valve and abortion of the TF-TAVR procedure. Indeed, the full balloon expansion to 6 mm post OA predicted with 100% accuracy the success of the TF-TAVR procedure. 

The 2-stage approach to vessel preparation is recommended for multiple reasons. It can be done either at the time of the coronary check prior to the TAVR, or as a planned intervention when the coronary anatomy is already defined. It minimizes the contrast use during index TAVR procedure, but most importantly, it predicts the success of TF-TAVR. All 19 cases where the OA facilitated full balloon inflation underwent successful TF-TAVR. The 1 case where the balloon inflation was incomplete in spite of multiple passes with a 2.0 crown translated into a failure to deliver the catheter valve. This finding allows operators to decide with high degree of confidence which case can be further treated with TF-TAVR, and when to default to an alternative access. As shown by Rymer et al,¹³ aborted TF-TAVR is associated with an increased risk of death and stroke. In their series, peripheral artery disease was the main reason for aborted procedures. Therefore, the ability to select the difficult access cases who are very likely to succeed via TF approach is very appealing. 

Study limitations. This study is limited by the relatively small number of subjects enrolled and by the single-center experience. Nevertheless, the safety signal was very strong, and the predictive value of TF-TAVR success following this strategy is compelling. Further experience involving multiple centers and a larger cohort of patients is warranted.

Orbital atherectomy used for vessel preparation in selected patients is a safe and very effective technique to facilitate TF-TAVR in patients with hostile peripheral anatomy.