TAVR Through Heavily Calcified Aorta Following Atheroma Retrieval With the "Elevator" Technique

Abstract: An 86-year-old Caucasian female with severe symptomatic, inoperable aortic stenosis was accepted for high-risk transfemoral transcatheter aortic valve replacement (TAVR) approach due to severe calcification of the aorta. During initial passage of a 22 Fr sheath, there was dislodgment with proximal migration of a circumferential tunnel of calcium from the infrarenal aorta. A novel “elevator” technique was used to secure and retrieve the dislodged aorta en bloc back to its original infrarenal aortic position and allow in situ fixation with stenting. A new TAVR system was then successfully placed through the stent and a 23 mm Edwards Sapien valve (Edwards Lifesciences) was implanted as planned. In case of calcification protruding into the lumen of the aorta and limiting the passage of the large valve delivery system sheath, the obstruction can be managed by stenting the calcification against the luminal wall under fluoroscopic and intravascular-ultrasound guidance, allowing successful passage of the valve delivery system. The elevator technique allows axial transportation of any calcified vascular fragments, should they become dislodged.

J INVASIVE CARDIOL 2015;27(10):E216-E219

Key words: aortic stenosis, drug-eluting stents, valve disease, new technique

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Case Report

An 86-year-old elderly female with past medical history of cirrhosis, emphysema, pituitary tumor surgery, hypertension, hyperlipidemia, diabetes, paroxysmal atrial fibrillation, and remote percutaneous coronary intervention with stents to proximal left anterior descending (LAD), diagonal (D1), and mid right coronary artery (RCA) presented with progressive dyspnea on exertion (New York Heart Association  class 3). She was diagnosed with severe aortic stenosis (aortic valve area, 0.7 cm² with peak and mean gradients of 67 mm Hg and 41 mm Hg, respectively) and normal left ventricular ejection fraction (60%). Her risk for mortality by standard EuroSCORE, logistic EuroSCORE, and STS score was found to be 9%, 11.4%, and 7.3%, respectively. She was deemed inoperable due to severe lung disease, severe diffuse aortic calcification, cirrhosis, and fraility. Hence, the option of transcatheter aortic valve replacement (TAVR) was considered. A comprehensive TAVR work-up was done. Angiography prior to TAVR procedure showed patent coronary stents with no other residual lesions elsewhere. A computed topography (CT) of the aorta was performed, which showed severe calcification in the course of the entire aorta from ascending to abdominal aorta (Figure 1). The narrowest diameter measured 0.78 x 0.79 cm at the level of the infrarenal aorta. An option of transapical TAVR was considered. However, the patient and family declined due to the significant lung disease and opted for the transfemoral approach, with understanding of the high-risk status due to diffusely calcified infrarenal aorta.

TAVR procedure was started as planned with right external iliac cut-down access and right radial artery access (5 Fr) as well as with left femoral vein (for pacemaker) and right internal jugular venous (for Swan-Ganz catheter) access sites due to  diffusely calcified disease in both femoral arteries. Anticoagulation was obtained with 5000 U heparin and activated clotting time was >250 seconds. Initially, a 12 Fr sheath was inserted, through which a balloon aortic valvuloplasty (BAV) was performed with a 20 mm Z-Med II balloon in a standard fashion. There was trace aortic regurgitation after BAV and peak gradient was reduced to 36 mm Hg. After removal of the valvuloplasty balloon, serial iliac dilators were exchanged over the Amplatz super-stiff wire and 22 Fr sheath was finally introduced and advanced in the aorta at the level of the thoraco-abdominal junction. Due to some difficulty in advancing the last dilator and the sheath, an angiogram was performed. It revealed no extravasation and the presence of calcified atheroma just beyond the sheath tip, which was not seen originally in the CT angiogram in this location (Figure 1 and Video 1). It was thought that the large dilator might have sheared off the longitudinal calcified atheroma from its original position (ie, infrarenal aorta) and pushed it proximally along with the sheath tip to the thoraco-abdominal junction. The patient remained hemodynamically stable at all times. Intravascular ultrasound (IVUS) of the aorta was performed and confirmed the above suspicion by detecting a cylindrical calcified tubular structure (tunnel-like) within the thoracic aorta just proximal to the sheath edge (Figure 2 and Video 2). We opted for a novel strategy, the “elevator” technique, to secure and then pull the dislodged calcified atheromatous tunnel back down to its original distal position (Figure 3). IVUS imaging confirmed that the minimal and maximal dimensions of the lumen within the level of the dislodged fragment were 4.6 mm x 8.1 mm. The diameter of the thoracic aorta above the dislodged cylindrical piece, as well as in between the calcified fragment and the sheath tip, measured 12.5 mm (due to acoustic shadowing, no IVUS imaging was feasible outside the cylindrical calcified piece). In order to secure the fragment from moving, a 20 mm aortic occlusion balloon was introduced over the stiff wire in the thoracic aorta. It was precisely centered at the most proximal edge of the dislodged atheroma, so that the lower half of the balloon would assume upon inflation the diameter of the cylindrical tunnel (approximately 4-8 mm), while the upper half of the balloon would assume the diameter of the thoracic aorta (approximately 12 mm), allowing the “lock” of the dislodged segment between the mushroom-shaped balloon edge and the sheath tip. As the long sheath also held the atheroma from below, a downward pull was thus possible on the entire balloon-atheroma-sheath system by a steady, slow movement. This downward elevator-like movement (Video 3) allowed the gradual return of the dislodged calcified atheroma to the infrarenal level. The exact positioning of the dislodged fragment above the aortic bifurcation and at the same time below the renal arteries was critical. Hence, the available zone to land the “elevator” was small in order to prevent renal failure and to proceed with TAVR as planned without contralateral iliac occlusion. After the elevator was leveled appropriately, an angiogram was performed (Video 4), which confirmed the position of the calcified atheroma in the infrarenal aortic position without any extravasation and preserved flow in renal arteries. We proceeded with stenting of the lesion. Implantation of a 14 x 80 mm self-expanding stent was initially attempted, but it was found to be too long to avoid covering the left iliac artery ostium (Video 5). Thus, a shorter 14 x 60 mm self-expanding version was used to stent the atheroma in place between the renal and iliac arteries (Video 6). A 12 mm balloon was then used to postdilate the stent at 10 atm. A pelvic angiogram revealed preserved flow in renal, mesenteric, and iliac arteries with widely patent stent (Video 7). We then proceeded with TAVR, utilizing a new 23 mm Edwards Sapien valve system (Edwards Lifesciences). The sheath was introduced easily through the stented portion of the infrarenal aorta (Figure 4) and reached the distal thoracic aorta under fluoroscopic guidance. TAVR was successfully completed; final transesophageal echocardiogram and aortogram showed mild aortic regurgitation only (Video 8). A pelvic angiogram was also performed in the end of the case (Video 9) and showed patent aortic stent without any extravasation. Hemostasis of right external iliac artery access site was successfully performed surgically by primary suture. Heparin anticoagulation was reversed with protamine. The patient had an uneventful postprocedure course without renal failure/contrast-induced nephropathy, neurological, or bleeding complications and was discharged on postoperative day 5 and completed 1-year follow-up.

Discussion

Since its first human use by Alain Cribier,¹ TAVR is increasingly utilized in clinical practice, following supportive clinical data² in extreme-risk and high-risk patients. It was found that 15.3% had major vascular complications and 11.9% had minor vascular complications after transfemoral TAVR (TF-TAVR) in the PARTNER trial (combination of cohorts A and B).³ Major vascular complications of TF-TAVR were associated with high mortality. The majority of these patients with severe peripheral arterial disease will have transapical TAVR or transaortic TAVR. Once our patient declined transapical TAVR, we considered ascending aorta access as well as transaxillary or transsubclavian access, none of which were feasible due to extensive calcification and small arterial size.

In our patient, we also considered the option of stenting the abdominal aorta before proceeding with TAVR, since the CT angiogram measurements were borderline regarding the feasibility of iliofemoral valve delivery. Staged treatment of aortic stenosis by TAVR and infrarenal aortic aneurysm by endovascular stent grafts had been described before,⁴ but the present patient’s disease was of different pathology and included  stenotic infrarenal aorta in combination with severe valvular aortic stenosis. Considering the hemodynamic severity of valvular aortic stenosis and availability of borderline-acceptable lumen as assessed by CT, we proceeded with TAVR with the anticipation of some difficulty in delivering the valve sheath. Although the infrarenal aortic diameter was larger than the nominal diameter of the valve delivery sheath, its angulated entry to the distal aorta ultimately caused dislodgment (“scraping” – “peeling” of a long, cylindrical calcified [“tunnel-like”] piece of atheroma), but not an aortic perforation. Strategies that may have been considered after dislodgment of the calcified atheroma from the infrarenal aorta included stenting at the level of thoraco-abdominal junction using covered or regular stent or relegating the patient to cardiopulmonary bypass for a surgical aortic valve replacement with embolectomy of the dislodged calcified atheroma. Proceeding with an endovascular stent graft was not attemped in our case due to the risk of covering distal thoracic aorta side branches such as lumbar arteries, artery of Adamkiewitz, and the celiac axis. The use of non-covered stent was not attempted since we were not sure of the compatibility to overdilate the 8 mm in-diameter segment (calcified atheroma) up to 12.5 mm in-diameter thoracic aorta segment. Indeed, the very heavy calcification of the dislodged fragment might have precluded full balloon expansion and the following circumstances might have developed: (1) complete absence of expansion with creation of a highly thrombogenic area between the dislodged segment and the thoracic aorta wall; (2) due to this complete absence of expansion, the fragment above the aorta might still be mobile; (3) in case of a partial fracture of the atheromatous cylinder, its apposition and fixation might still be unfeasible and at the same time, the elevator technique might just complete the fracture rather than securely transporting it en bloc to the desired location. We therefore devised a novel elevator technique to bring the atheroma back down to its “ground floor” original location and stent at precisely the right location.

To the best of our knowledge, proximal dislodgment of calcified atheroma from infrarenal aorta during TAVR that was later pulled down to its original distal aortic site has never been described. Hence, the elevator technique, with a partially inflated locking balloon above the migrated/dislodged atheroma with the support of the sheath from below can achieve upward or downward (proximal or distal) movement en bloc until the optimal spot is reached for fixation with balloon and stent. The avoidance of only partial movement of the dislodged aortic fragment is also vital, and is analogous to avoiding the elevator stopping in between the floors. In this particular case, we successfully moved the atheroma back down to the infrarenal aorta (approximately 120 mm) and the elevator technique allowed the secure over-the-wire transportation of the atheromatous piece to any arterial location that could accommodate its diameter.

References

1. Cribier A, Eltchaninoff H, Bash A, et al. Percutaneous transcatheter implantation of an aortic valve prosthesis for calcific aortic stenosis: first human case description. Circulation. 2002;106:3006-3008.
2. Kodali SK, Williams MR, Smith CR, et al. Two-year outcomes after transcatheter or surgical aortic-valve replacement. N Engl J Med. 2012; 366:1686-1695. 
3. Généreux P, Webb JG, Svensson LG, et al. Vascular complications after transcatheter aortic valve replacement: insights from the PARTNER (Placement of AoRTic TraNscathetER Valve) trial. J Am Coll Cardiol. 2012;60:1043-1052. 
4. Ghosh-Dastidar M, Dworakowski R, Lioupis C, et al. The combined treatment of aortic stenosis and abdominal aortic aneurysm using transcatheter techniques: a case report. J Cardiovasc Surg (Torino). 2011;52:895-898. Epub 2011 Jun 29.

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From Mount Sinai Medical Center, New York, New York. 

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Sharma reports speaker’s bureau fees from Abbott Vascular, Boston Scientific, Angioscore, Cardiovascular Systems, Inc, and LillyDSI. The remaining authors report no conflicts of interest regarding the content herein.

Manuscript submitted January 30, 2015, final version accepted February 2, 2015.

Address for correspondence: George D. Dangas, MD, Mount Sinai Medical Center, New York, NY 10029. Email: George.Dangas@MountSinai.org