Rota Rescue: Avoiding Regret

Case 

This report describes a 63-year-old male with a history of hypertension, tobacco usage, and hypercholesteremia, who was recently admitted with new onset atrial fibrillation. He had new onset left ventricular (LV) dysfunction on echocardiography, and a subsequent cardiac cath demonstrated a high-grade stenosis in the mid right coronary artery (RCA) with calcification. Initial revascularization was deferred until further work up for lung mass. He had a PET scan that was negative, and was staged for intervention the following week; however, he came in with chest pain and therefore, revascularization was performed.

Access was obtained in the left radial artery with a Terumo Slender 6 French (Fr) sheath. A 6 Fr Judkins right (JR) 4 guide was used to engage the right coronary system. Angiographically, the RCA had a mid-80% calcified stenosis. It was approximately a 10 mm lesion. The remaining RCA was widely patent. It was a large-caliber, dominant vessel, giving rise to a large posterior descending artery (PDA) and posterolateral vein (PLV).

Bivalirudin was initiated. A Runthrough wire (Terumo) was passed distally and predilatation was initially attempted with a 3.0 x 10 mm AngioSculpt (Spectranetics). It was unsuccessful in terms of getting the lesion to yield. A 3.5 x 12 mm Emerge (Boston Scientific) was utilized, but a significant waist remained in the focal segment. We returned to the AngiosSculpt at 24 atmospheres (atm); again, the lesion would not yield. After multiple inflations at 60 seconds and then 90 seconds at 24 atm, the lesion still did not yield. We went ahead and advanced a Rotawire (Boston Scientific) and used a 1.75 burr to perform rotational atherectomy and then went back with the same series of balloon dilatations. Aggressive dilation did not get the vessel to yield. An additional Runthrough .014-inch 300 cm wire was placed in place of the Rotawire. The guide was removed over the .014-inch wire and the .035-inch wire. The 6 Fr sheath was removed and a 7 Fr sheath inserted over the two wires, removing the .035-inch wire prior to re-engaging the RCA over the .014-inch wire, thus maintaining wire position during this process. The Rotawire was re-advanced and we utilized a 2.0 burr. There was some bradycardia with the 2.0 burr, but we were able to make polishing runs. We then tried the 3.0 x 15 mm Flextome cutting balloon (Boston Scientific) and a 3.5 x 15 mm Flextome, and again, could not get the vessel to yield despite high-pressure inflations of 18 atm with the Flextome. At this point, it was felt that the next step would be a 2.25 burr, which was not available in the lab. We therefore removed the wires and angiographically had TIMI-3 flow. No visible angiographic dissection or perforation was noted, with normal flow. There was no significant angiographic improvement in the lesion, despite the aggressive balloon manipulation and rotational atherectomy. The patient was placed on tirofiban and brought back after 48 hours, once 2.25 and 2.5 burrs were obtained. 

Videos:
Video 2. Dilatation with a 3.5 mm x 12 mm balloon.
Video 3. 1.75 burr.
Video 4. Guide exchange over long Runthrough (300 cm) and 260 cm exchange .035-inch wire (being removed).
Video 5. Seating guide over the long Runthrough wire.
Video 6. 2.25 mm burr.
Video 7. Final angiogram after first procedure.
Video 8. Flextome with buddy wire.
Video 9. Final angiogram after stent.

Due to the need for a 9 Fr sheath to accommodate the largest burr, femoral access was obtained. The right groin was prepped and draped in sterile fashion. The right groin was accessed, Preclose was performed, and 9 Fr sheath inserted. We used a 9 Fr JR 4 guide to engage the RCA system. Angiographically, the RCA had a mid-80% stenosis, a heavily calcified lesion about 15 mm in length. Bivalirudin was administered. A Samurai wire (Boston Scientific) was advanced distally and then to secure the guide, a Rotawire (Boston Scientific). The Samurai wire was removed, a 2.25 burr was advanced and multiple passes were performed. The patient did have asystole during the runs and the runs had to be kept to less than 10 seconds at 160 revolutions per minute (rpm) to allow the heart rate to recover. At one point, we had the burr get stuck. It was removed with slight traction and injection of Rotaglide. Polishing runs were made with the 2.25 burr without any hemodynamic compromise. We removed the burr and exchanged the Rotawire for the Samurai wire. A 3.5 x 10 mm Flextome cutting balloon (Boston Scientific) was advanced and pre-dilated, and this time, the Flextome fully expanded at 16 atm (the previous week expansion was attempted at 24 atm, with the lesion not yielding). Once we had good balloon dilatation, a Runthrough wire was advanced for a buddy wire to place a stent. A 4.0 x 28mm Synergy drug-eluting stent (Boston Scientific) was advanced. The buddy wire was removed and the stent was deployed at 14 atm and then post dilated with a 4.5 NC Emerge (Boston Scientific) at high pressure. Post-procedure IVUS Opticross (Boston Scientific) demonstrated full apposition of the drug-eluting stent. The patient tolerated the procedure well and was discharged the following morning. 

Discussion

It has been over 25 years since rotational atherectomy was introduced as one of several tools to treat coronary obstruction by physically removing plaque. Although initially considered as an alternative to angioplasty, it soon became complementary to treat, in particular, calcified lesions. The data, however, have not demonstrated a long-term benefit on  major adverse cardiac events (MACE) and restenosis. Current data suggest less than 5% use of rotational atherectomy¹; however, this may change as lesion preparation will be more imperative in the era of bioresorbable scaffolds. 

The Rotablator (Boston Scientific) ablates plaque using a diamond-encrusted elliptical burr, rotated at high speeds (140,000 to 180,000 rpm) by a helical drive shaft that advances gradually across a lesion over a proprietary guidewire. The burr preferentially ablates hard, inelastic material, such as calcified plaque, that is less able to stretch away from the advancing burr than is healthy arterial wall (differential cutting). High rotational speeds facilitate longitudinal burr movement across calcific lesions by orthogonal displacement of friction.^2-4

Two trials have demonstrated increased procedural success with rotational atherectomy in calcified lesions. In the ERBAC trial, 685 patients were randomized to various atherectomy methods. The primary endpoint was procedural success. Lesions treated in this study were severe, with >70% classified as American Heart Association (AHA)/American College of Cardiology (ACC) type B2 or C. Though the initial procedural success was greatest in patients treated with rotational atherectomy (RA) [89% (RA) vs 77% (excimer laser coronary angioplasty, ELCA) vs 80% (percutaneous transluminal coronary angioplasty, PTCA)], target lesion revascularization (TLR) at 1 year was significantly increased.⁵ Similar results were also found in the COBRA trial. Five hundred and two patients with heavily calcified and complex lesions were randomized to RA vs PTCA. Procedural success was greatest with RA (85% vs 78%; P<0.05), but there was no difference in restenosis, TLR, or symptomatic outcome at 6 months.⁶ As a result, rotational atherectomy is typically used in heavily calcified lesions where inadequate vessel preparation may result in procedural failure, stent under deployment (a risk factor for stent thrombosis), and increased restenosis. This may be of more value with drug-eluting stents (DES), as manipulation of DES through calcified lesions can potentially disrupt the polymer coating; suboptimal deployment of DES in these complex lesions may further increase the risk of stent thrombosis already posed by the delayed endothelialization; local delivery of drug could be impaired; and finally, DES have a twofold higher failure to deliver rates when compared with BMS in calcified lesions.⁷ Atherectomy could potentially address these issues.

Adjunctive therapy with an atherotomy balloon (or a “focal force” technique), in this case a cutting balloon, provides better torsional, longitudinal, and radial force compared to balloon angioplasty. The microtome edge initiates an indentation into the plaque, after which, the shear force applied by the balloon inflation propagates the crack. Depending on balloon size, the cutting force at the blade edge is enhanced 200,000 to 400,000 times.⁸ Other options for treating this lesion include more aggressive dilation with larger balloons. Aggressive dilation has the potential to result in coronary perforation or dissection, or balloon rupture, and a resulting high-pressure contrast jet causing subintimal dissection. However, this method is readily available and does not require any additional capital equipment; hence this is a typical first approach to treat undilatable lesions. This approach can be modified with use of a buddy wire or atherotomy balloon. The created “focal force” may reduce circumferential plaque dissection and enhance longitudinal plaque fissuring. However, when a lesion proves resistant to this approach, alternative options need to be considered, which can include atherectomy (laser, rotational, or orbital atherectomy) or surgical revascularization. In this particular lesion, a larger laser with contrast may have achieved the same result. However, the larger laser catheters have shorter runs, and the addition of contrast increases the acousticomechanical effect and the potential for complications. Given the limit in crown size, orbital atherectomy likely would not have achieved adequate plaque modification, but remains a consideration.  

References

1. Mota P, Santos R, Pereira H, et al. Facts on rotational atherectomy for coronary artery disease: multicentric registry (abstr). Paper presented at: EuroPCR; May 21, 2013; Paris, France.
2. Hansen DD, Auth DC, Vracko R, et al. Rotational atherectomy in atherosclerotic rabbit iliac arteries. Am Heart J. 1988; 115 (Part 1): 160-165. 
3. Hansen DD, Auth DC, Vracko R, et al. Mechanical thrombectomy: A comparison of two rotational devices and balloon angioplasty in subacute canine femoral thrombosis. Am Heart J. 1987; 114: 1223-1231.
4. Safian RD, Freed MS. The Manual of Interventional Cardiology. Royal Oak: Physicians’ Press; 2002. p 618.
5. Reifart N, Vandormael M, Krajcar M, et al. Randomized comparison of angioplasty of complex coronary lesions at a single center. Excimer Laser, Rotational Atherectomy, and Balloon Angioplasty Comparison (ERBAC) Study. Circulation. 1997; 96:91-98. 
6. Dill T, Dietz U, Hamm CW, et al. A randomized comparison of balloon angioplasty versus rotational atherectomy in complex coronary lesions (COBRA study). Eur Heart J. 2000; 21: 1759-1766.
7. Moussa I, Ellis SG, Jones M, et al. Impact of coronary culprit lesion calcium in patients undergoing paclitaxel-eluting stent implantation (a TAXUS-IV sub study). Am J Cardiol. 2005; 96: 1242-1247.
8. Michiels R. Cutting balloon system technology: The engineering perspective. J Invasive Cardiol. 1996;8: 6A-8A.

Disclosures: Orlando Marrero reports he is a consultant for Boston Scientific. Dr. Zaheed Tai reports the following: speaker/proctor for Terumo, Spectranetics, Boston Scientific, and Abiomed.  

Orlando Marrero, RCIS, MBA can be contacted at orlm8597@icloud.com. 

Dr. Zaheed Tai can be contacted at zaheedtai@gmail.com.