- Email: [email protected]
Comparison of Rotational Atherectomy Versus Orbital Atherectomy for the Treatment of Heavily Calcified Coronary Plaques
Comparison of Rotational Atherectomy Versus Orbital Atherectomy for the Treatment of Heavily Calcified Coronary Plaques Michael S. Lee, MDa,*, Kyung Woo Park, MD, PhDb, Evan Shlofmitz, DOc, and Richard A. Shlofmitz, MDd We evaluated the outcomes of patients with severe coronary artery calcification (CAC) who underwent rotational atherectomy (RA) and orbital atherectomy (OA). Severe CAC increases the complexity of percutaneous coronary intervention (PCI) because of the difficulty in optimizing stent expansion, leading to worse clinical outcomes. Both devices are effective treatment strategies for severe CAC. No comparisons have been performed to evaluate the clinical outcomes after RA and OA. The outcomes of 67 patients with severe CAC who underwent RA from July 2012 to June 2015 and 60 patients who underwent OA from February 2014 to September 2016 were evaluated. The primary end point was the rate of 30-day major adverse cardiac and cerebrovascular events, comprising cardiac death, myocardial infarction, target vessel revascularization, and stroke. The primary end point was similar in the RA and OA groups (6% vs 6%, p >0.9), as were the individual end points of death (0% vs 2%, p [ 0.8), myocardial infarction (6% vs 4%, p [ 0.7), target vessel revascularization (0% vs 0%, p >0.9), and stroke (0% vs 0%, p >9). Procedural success was achieved in all patients. Angiographic complications were uncommon in both groups. No patient had stent thrombosis. In conclusion, both RA and OA are safe and effective for the treatment of severe CAC as they provided similar clinical outcomes at short-term follow-up. Ó 2017 Elsevier Inc. All rights reserved. (Am J Cardiol 2017;119:1320e1323) Coronary artery calcification (CAC) was observed in 38% of all lesions with angiography and 74% with intravascular ultrasound.1 The treatment of severe CAC is technically challenging because of the difficulty in advancing balloons and stents and achieving optimal stent expansion, which may increase the risk of stent thrombosis and in-stent restenosis.2 Forceful advancement of a drugeluting stent in a heavily calcified lesion may damage the polymer coating. Percutaneous coronary intervention (PCI) of severe CAC is associated with worse clinical outcomes.3,4 Coronary atherectomy devices modify the calcified plaque to facilitate stent delivery and optimize stent expansion. The guidelines for PCI provide a class IIa recommendation for the use of rotational atherectomy (RA) for the treatment of fibrotic or heavily calcified plaques that cannot be crossed by a balloon catheter or adequately dilated before stent implantation (level of evidence C).5 The Evaluate the Safety and Efficacy of OAS in Treating Severely Calcified Coronary Lesions (ORBIT II) trial reported the
a Division of Cardiology, UCLA Medical Center, Los Angeles, California; bDepartment of Internal Medicine and Cardiovascular Center, Seoul National University Hospital, Seoul, Republic of Korea; cDepartment of Cardiology, Northwell Health, Manhasset, New York; and dCardiology Department, St. Francis Hospital-The Heart Center, Roslyn, New York. Manuscript received November 26, 2016; revised manuscript received and accepted January 18, 2017. See page 1323 for disclosure information. *Corresponding author: Tel: 310-696-9523; fax: 310-825-9012. E-mail address: [email protected] (M.S. Lee).
0002-9149/17/$ - see front matter Ó 2017 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.amjcard.2017.01.025
safety and efficacy of orbital atherectomy (OA) up to 3 years, including a low rate of target lesion revascularization.6e8 We report the first evaluation of clinical outcomes comparing RA with OA for the treatment of severe CAC. Methods This retrospective analysis included 67 consecutive patients who underwent RA from July 2012 to June 2015 and 50 consecutive patients who underwent OA from January 2015 to September 2016 at the UCLA Medical Center, Los Angeles, California. All patients had severe CAC, as defined by the presence of radio-opacities on fluoroscopy of the vessel wall. Patients who presented with ST-elevation myocardial infarction were excluded. The institutional review board approved the review of the data. Rotational atherectomy (Boston Scientific, Maple Grove, Minnesota) contains a rotating olive-shaped burr coated with 2,000 to 3,000 microscopic diamond chips that modifies the calcified plaque and changes vessel compliance. The other components include the console, a nitrogen tank, and a turbine that is activated by a foot pedal. The burr, which is bonded to the drive shaft, advances over a 0.009-inch RotaWire (Boston Scientific). A Rota-flush solution containing 10,000 units of heparin in a 1-liter bag of normal saline solution was infused through the drive shaft to minimize the heat and friction between the device and RotaWire. The coronary orbital atherectomy device (Cardiovascular Systems, Inc. [CSI], St Paul, Minnesota) requires the ViperSlide (CSI) lubricant that is continuously infused through the drive shaft to minimize heat generation and www.ajconline.org
Coronary Artery Disease/RA Versus OA for Severely Calcified Coronary Lesions Table 1 Baseline clinical characteristics Variable Age (years) Men Diabetes mellitus Hypertension Hypercholesterolemia Prior stroke Previous myocardial infarction Previous percutaneous coronary intervention Previous coronary artery bypass grafting Left ventricular ejection fraction (%) Elective percutaneous coronary intervention Acute coronary syndrome Unstable angina Non-ST-elevation myocardial infarction ST-elevation myocardial infarction
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Table 2 Procedural characteristics RA (N¼67) 61 12 46 (69%) 26 (39%) 44 (66%) 43 (64%) 5 (7%) 16 (24%) 19 (28%) 88 (12%) 52 13 45 (67%) 22 (33%) 15 (22%) 7 (10%) 0
OA p-value (N¼50) 62 11 34 (68%) 18 (36%) 38 (76%) 36 (72%) 3 (6%) 11 (22%) 15 (30%) 5 (10%) 51 12 34 (68%) 16 (32%) 12 (24%) 4 (8%) 0
0.8 0.9 0.8 0.4 0.3 0.9 0.8 0.8 0.8 0.8 0.9 0.9
OA ¼ orbital atherectomy; RA ¼ rotational atherectomy.
friction. A 1.25-mm crown is coated with 30-mm diamonds and eccentrically mounted to expand laterally while rotating as a result of centrifugal force and is advanced over the 0.01400 ViperWire (CSI). A 6F guiding catheter was used for all cases. Standard techniques for PCI were used. All patients were pretreated with dual antiplatelet therapy before PCI. Unfractionated heparin was administered to maintain the activated clotting time >250 seconds. It was the discretion of the operator to insert a temporary pacing lead, use a hemodynamic support device, and use intravascular ultrasound for the assessment of lesion morphology and stent expansion. Drug-eluting stents were implanted unless there was a contraindication to prolonged dual antiplatelet therapy. The typical burr-to-artery ratio was 0.5. However, if the lesion was severely stenotic and the reference vessel diameter was 3 mm, a 1.25-mm burr was initially used followed by larger burrs. The RA burr was tested and primed before insertion into the guiding catheter at 150,000 to 170,000 rpm while being mounted on the RotaWire. After all patients were treated with low-speed (80,000 rpm) atherectomy, high-speed (120,000 rpm) atherectomy was performed if the reference vessel diameter was at least 3 mm. Each pass was limited to 20 seconds. The duration of the dual antiplatelet therapy was at least 1 month for a bare metal stent and 1 year for a drug-eluting stent. The primary end point was the rate of 30-day major adverse cardiac and cerebrovascular events, defined as the composite of death, myocardial infarction (MI), target vessel revascularization (TVR), and stroke. MI was defined as recurrent symptoms with new ST-segment elevation or re-elevation of cardiac markers to at least twice the upper limit of normal. TVR was defined as repeat revascularization of the target vessel. The Academic Research Consortium definition of stent thrombosis was used.9 Procedural success was defined as residual stenosis 30% and thrombolysis in myocardial infarction grade 3 flow without death, emergency coronary artery bypass graft
Variable Anticoagulation Heparin Patients pretreated with clopidogrel Vascular access Transfemoral Transradial Maximum burr size (mm) OA device speed (revolutions/min) Low only, 80,000 Low and high, 80,000 and 120,000 Burr(s) per case Passes per case Type of stent Drug-eluting Bare metal Stents per case Vessels treated Temporary pacemaker Intra-aortic balloon pump Impella Extracorporeal membrane oxygenation Bail-out use of GP IIb/IIIa inhibitors Final TIMI flow 0-1 2 3 French size 6F 8F
RA (N¼67)
OA (N¼50)
67 (100%) 50 (100%) 65 (97%) 48 (96%) 66 (99%) 1 (1%) 1.5 0.1
47 (94%) 3 (6%) NA
NA NA 1.3 0.2 3.6 1.2
14 (28%) 36 (72%) NA 3.3 1.3
61 (91%) 7 (9) 1.4 0.6 1.3 0.2 5 (7%) 6 (9%) 2 (3%) 0 0
46 (92%) 4 (8) 1.5 0.4 1.3 0.3 0 2 (4%) 1 (2%) 1 (2%) 0
p-value
>0.9 0.9 0.7
0.7 0.9
0.7 0.9 0.2 0.3 0.9 0.9 >0.9 >0.9
0 0 0 0 67 (100%) 50 (100%) 0.6 63 (94%) 4 (6%)
50 (100%) 0
NA ¼ not applicable; OA ¼ orbital atherectomy; RA ¼ rotational atherectomy.
surgery, and/or PCI during the first 24 hours. Data on angiographic complications included perforation, dissection leading to less than thrombolysis in myocardial infarction grade 3 flow, and no reflow. Baseline demographic and procedural data and adverse clinical events were entered into a dedicated PCI database. Continuous variables are presented as mean SD and compared using the Student t test. Categorical variables are presented as percentages and compared using the chi-square test. A p value <0.05 was considered statistically significant. All data were processed with SPSS (version 20.0, SPSS-PC, Inc., Chicago, Illinois). Results Baseline demographic and procedural characteristics were well matched in both groups (Tables 1 and 2). Procedural success and angiographic complications were similarly low in both groups (Table 3). The primary end point was similar in the RA and OA groups (6% vs 6%, p >0.9), as were the individual end points of death (0% vs 2%, p ¼ 0.8), MI (6% vs 4%, p ¼ 0.7), TVR (0% vs 0%, p >0.9), and stroke (0% vs 0%, p >9) (Table 4). The 1 patient who died was a 43-year-old man who had cardiac arrest at home, had cardiopulmonary resuscitation, was intubated, and had enhanced
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Table 3 Angiographic complications Variable Procedural success Perforation Cardiac tamponade Dissection leading to less than TIMI grade 3 flow No reflow Stent loss
RA (N¼67)
OA (N¼50)
p value
67 (100%) 0 0 0
50 (100%) 1 (2%) 1 (2%) 0
>0.9 0.9 0.9 >0.9
5 (7%) 0
2 (4%) 0
0.4 >0.9
OA ¼ orbital atherectomy; RA ¼ rotational atherectomy. Table 4 Clinical Events at 30 days Variable
RA (N¼67)
OA (N¼50)
p value
Major adverse cardiac and cerebrovascular events Cardiac death Myocardial infarction Target vessel revascularization Stroke Stent thrombosis
4 (6%)
3 (6%)
>0.9
0 4 (6%) 0 0 0
1 (2%) 2 (4%) 0 0 0
0.8 0.7 >0.9 >0.9 >0.9
OA ¼ orbital atherectomy; RA ¼ rotational atherectomy.
extracorporeal membrane oxygenation initiated for cardiogenic shock despite being treated with 4 vasopressors. He underwent emergent orbital atherectomy of the left main and left anterior descending arteries because he was not a candidate for surgical revascularization. No patients experienced stent thrombosis. Discussion In the first analysis that compared clinical outcomes of OA with those of RA, the main finding of this study was that both devices were safe and effective for the treatment of severe CAC, with low rates of angiographic complications and adverse clinical outcomes. OA is faster to set up and easier to use because it does not require a nitrogen tank or a foot pedal to activate the device. The mechanism of action, centrifugal force, involves the crown spinning on the ViperWire and orbiting along the periphery of the vessel to debulk the plaque even further with each pass, whereas the RA burr has only 1 axis of rotation on the RotaWire and ablates a fixed diameter. The single axis of rotation also gives rise to the possibility of burr entrapment because it ablates only in the antegrade direction because of the lack of diamond coating on the proximal portion of the burr. In contrast, the OA ablates bidirectionally, lowering the risk of crown entrapment. The operator has fingertip control to switch from low speed to high speed to treat a larger vessel diameter because of ablation of a larger radius. With RA, an assistant is required to adjust the speed on the console, and the burr requires removal, exchange to a larger burr, and readvancement to progressively ablate more extensively for large vessels, increasing the procedural time and complexity of the case.
Larger burrs (1.75 mm) require 7F guiding catheters, whereas OA can be performed with a 6F guiding catheter for all cases. Because of the single axis of rotation, the burr is in constant contact with the plaque, resulting in thermal injury and platelet activation.10 The average particulate size with RA is 5 mm, and particles are released in boluses compared with the OA crown, which is in intermittent contact and continuously releases 2-mm particles, accounting for less distal embolization and the differences in the rates of slow/ no-flow with RA (2% to20%) and OA (0.9%).6,11e14 A disadvantage of RA is that the RotaWire needs to be exchanged for a workhorse wire. This may be explained by the fact that it has a 0.009-inch-diameter shaft and is not supportive enough to advance balloons and stents. The ViperWire, which has a 0.012-inch-diameter shaft, can support the advancement of balloons and stents. It can be cut with a scissor to approximate the length of a 160-cm guidewire to complete the PCI. Another potential advantage of OA may be in patients with angulated and eccentric lesions. The guidewire may lie preferentially against the wall of the vessel as opposed to the center, so-called guidewire bias, as a result of the contour of the vessel and the position of the guiding catheter. The burr may ablate asymmetrically on the RotaWire, possibly creating a “furrow” as opposed to debulking throughout the entire vessel. The angle of the vessel correlated with the pre-RA and post-RA luminal changes in the vertical axis but not the horizontal axis, validating the guidewire bias effect. Asymmetric CAC may further augment guidewire bias because the RotaWire may not guide the burr toward the calcified lesion, leading to inadequate ablation during advancement, increasing the risk of burr entrapment. In contrast, the orbital movement of the crown may overcome these issues because it ablates throughout the entire circumference of the vessel and is less influenced by the guidewire position or the eccentricity of the calcified plaque. Optical coherence tomography demonstrated that compared with RA, OA resulted in more modification of the plaque, including longer cuts and deeper dissections, which may explain the lower percentage of stent strut malapposition and a trend toward improved stent expansion.15 Rotational atherectomy may be preferred in treating aorto-ostial disease because OA is associated with suboptimal anchoring and stabilization of the proximal portion of the device while inside the guiding catheter. One technique to overcome this issue is to initially advance the crown distally followed by ablating the aorto-ostial lesion while pulling back the device proximally. Another technique is to firmly engage the tip in the calcified aorto-ostial lesion to constrain its orbit before activating the device. The ORBIT II trial excluded patients with vessels >4 mm.6 The 1.25-mm crown orbiting at high speed may not sufficiently modify plaque in larger vessels. A 2-mm RA burr might be preferred in these larger vessels. Patients with vessels <2.5 mm were also excluded because the 1.25-mm crown may be too large and increase the risk of perforation. The tip of the OA device does not have an ablative surface and may not traverse subtotally occluded calcified lesions. The ablative surface is at the tip of the burr and may be preferred to cross subtotal occlusions.
Coronary Artery Disease/RA Versus OA for Severely Calcified Coronary Lesions
This study was a small, retrospective one from a single center. The duration of follow-up was short. Quantitative coronary angiography and angiographic follow-up were not performed. Cardiac biomarkers were not routinely obtained on all patients after PCI. Atherectomy with the respective devices were performed at 2 different time intervals. Disclosure
7.
8.
The authors have no conflicts of interest to disclose. 9. 1. Mintz GS, Popma JJ, Pichard AD, Kent KM, Satler LF, Chuang YC, Ditrano CJ, Leon MB. Patterns of calcification in coronary artery disease. A statistical analysis of intravascular ultrasound and coronary angiography in 1155 lesions. Circulation 1995;91:1959e1965. 2. Lee MS, Shah N. The impact and pathophysiologic consequences of coronary artery calcium deposition in percutaneous coronary interventions. J Invasive Cardiol 2016;28:160e167. 3. Lee MS, Yang T, Lasala J, Cox D. Impact of coronary artery calcification in percutaneous coronary intervention with paclitaxel-eluting stents: two-year clinical outcomes of paclitaxel-eluting stents in patients from the ARRIVE program. Catheter Cardiovasc Interv 2016;88:891e897. 4. Arora S, Panaich SS, Patel N, Patel NJ, Savani C, Patel SV, Thakkar B, Sonani R, Jhamnani S, Singh V, Lahewala S, Patel A, Bhatt P, Shah H, Jaiswal R, Gupta V, Deshmukh A, Kondur A, Schreiber T, Badheka AO, Grines C. Coronary atherectomy in the United States (from a Nationwide Inpatient Sample). Am J Cardiol 2016;117:555e562. 5. Levine GN, Bates ER, Blankenship JC, Bailey SR, Bittl JA, Cercek B, Chambers CE, Ellis SG, Guyton RA, Hollenberg SM, Khot UN, Lange RA, Mauri L, Mehran R, Moussa ID, Mukherjee D, Nallamothu BK, Ting HH. 2011 ACCF/AHA/SCAI guideline for percutaneous coronary intervention. A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions. J Am Coll Cardiol 2011;58:e44ee122. 6. Chambers JW, Feldman RL, Himmelstein SI, Bhatheja R, Villa AE, Strickman NE, Shlofmitz RA, Dulas DD, Arab D, Khanna PK, Lee AC, Ghali MG, Shah RR, Davis TP, Kim CY, Tai Z, Patel KC, Puma JA,
10.
11. 12. 13.
14.
15.
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Makam P, Bertolet BD, Nseir GY. Pivotal trial to evaluate the safety and efficacy of the orbital atherectomy system in treating de novo, severely calcified coronary lesions (ORBIT II). JACC Cardiovasc Interv 2014;7:510e518. Généreux P, Lee AC, Kim CY, Lee M, Shlofmitz R, Moses JW, Stone GW, Chambers JW. Orbital atherectomy for treating de novo severely calcified coronary narrowing (1-year results from the pivotal ORBIT II trial). Am J Cardiol 2015;115:1685e1690. Chambers J. Orbital Atherectomy Treatment of Severely Calcified Coronary Lesions: Final 3-year Results of the ORBIT II Trial. Cardiovascular Research Technologies (CRT) Conference. Washington, D. C. Washington, D.C.; 2016. Cutlip DE, Windecker S, Mehran R, Boam A, Cohen DJ, van Es GA, Steg PG, Morel MA, Mauri L, Vranckx P, McFadden E, Lansky A, Hamon M, Krucoff MW, Serruys PW; Academic Research Consortium. Clinical end points in coronary stent trials: a case for standardized definitions. Circulation 2007;115:2344e2351. Lovik, R.D., Abraham, J.P., & Sparrow, E.M. (2009). Assessment of possible thermal damage of tissue due to atherectomy by means of a mechanical debulking device. In Proceedings of the ASME Summer Bioengineering Conference, SBC2008. (PART B ed., pp. 799e800). Zheng Y, Belmont B, Shigh AJ. Experimental investigation of the abrasive crown dynamics in orbital atherectomy. Med Eng Phys 2016;38:639e647. Hansen DD, Auth DC, Vracko R, Ritchie JL. Rotational atherectomy in atherosclerotic rabbit iliac arteries. Am Heart J 1988;115:160e165. Sakakura K, Funayama H, Taniguchi Y, Tsurumaki Y, Yamamoto K, Matsumoto M, Wada H, Momomura SI, Fujita H. The incidence of slow flow after rotational atherectomy of calcified coronary arteries: a randomized study of low speed versus high speed. Catheter Cardiovasc Interv 2016. http://dx.doi.org/10.1002/ccd.26698. Kini A, Marmur JD, Duvvuri S, Dangas G, Choudhary S, Sharma SK. Rotational atherectomy: improved procedural outcome with evolution of technique and equipment. Single-center results of first 1,000 patients. Catheter Cardiovasc Interv 1999;46:305e311. Kini AS, Vengrenyuk Y, Pena J, Motoyama S, Feig JE, Meelu OA, Rajamanickam A, Bhat AM, Panwar S, Baber U, Sharma SK. Optical coherence tomography assessment of the mechanistic effects of rotational and orbital atherectomy in severely calcified coronary lesions. Catheter Cardiovasc Interv 2015;86:1024e1032.
a Division of Cardiology, UCLA Medical Center, Los Angeles, California; bDepartment of Internal Medicine and Cardiovascular Center, Seoul National University Hospital, Seoul, Republic of Korea; cDepartment of Cardiology, Northwell Health, Manhasset, New York; and dCardiology Department, St. Francis Hospital-The Heart Center, Roslyn, New York. Manuscript received November 26, 2016; revised manuscript received and accepted January 18, 2017. See page 1323 for disclosure information. *Corresponding author: Tel: 310-696-9523; fax: 310-825-9012. E-mail address: [email protected] (M.S. Lee).
0002-9149/17/$ - see front matter Ó 2017 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.amjcard.2017.01.025
safety and efficacy of orbital atherectomy (OA) up to 3 years, including a low rate of target lesion revascularization.6e8 We report the first evaluation of clinical outcomes comparing RA with OA for the treatment of severe CAC. Methods This retrospective analysis included 67 consecutive patients who underwent RA from July 2012 to June 2015 and 50 consecutive patients who underwent OA from January 2015 to September 2016 at the UCLA Medical Center, Los Angeles, California. All patients had severe CAC, as defined by the presence of radio-opacities on fluoroscopy of the vessel wall. Patients who presented with ST-elevation myocardial infarction were excluded. The institutional review board approved the review of the data. Rotational atherectomy (Boston Scientific, Maple Grove, Minnesota) contains a rotating olive-shaped burr coated with 2,000 to 3,000 microscopic diamond chips that modifies the calcified plaque and changes vessel compliance. The other components include the console, a nitrogen tank, and a turbine that is activated by a foot pedal. The burr, which is bonded to the drive shaft, advances over a 0.009-inch RotaWire (Boston Scientific). A Rota-flush solution containing 10,000 units of heparin in a 1-liter bag of normal saline solution was infused through the drive shaft to minimize the heat and friction between the device and RotaWire. The coronary orbital atherectomy device (Cardiovascular Systems, Inc. [CSI], St Paul, Minnesota) requires the ViperSlide (CSI) lubricant that is continuously infused through the drive shaft to minimize heat generation and www.ajconline.org
Coronary Artery Disease/RA Versus OA for Severely Calcified Coronary Lesions Table 1 Baseline clinical characteristics Variable Age (years) Men Diabetes mellitus Hypertension Hypercholesterolemia Prior stroke Previous myocardial infarction Previous percutaneous coronary intervention Previous coronary artery bypass grafting Left ventricular ejection fraction (%) Elective percutaneous coronary intervention Acute coronary syndrome Unstable angina Non-ST-elevation myocardial infarction ST-elevation myocardial infarction
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Table 2 Procedural characteristics RA (N¼67) 61 12 46 (69%) 26 (39%) 44 (66%) 43 (64%) 5 (7%) 16 (24%) 19 (28%) 88 (12%) 52 13 45 (67%) 22 (33%) 15 (22%) 7 (10%) 0
OA p-value (N¼50) 62 11 34 (68%) 18 (36%) 38 (76%) 36 (72%) 3 (6%) 11 (22%) 15 (30%) 5 (10%) 51 12 34 (68%) 16 (32%) 12 (24%) 4 (8%) 0
0.8 0.9 0.8 0.4 0.3 0.9 0.8 0.8 0.8 0.8 0.9 0.9
OA ¼ orbital atherectomy; RA ¼ rotational atherectomy.
friction. A 1.25-mm crown is coated with 30-mm diamonds and eccentrically mounted to expand laterally while rotating as a result of centrifugal force and is advanced over the 0.01400 ViperWire (CSI). A 6F guiding catheter was used for all cases. Standard techniques for PCI were used. All patients were pretreated with dual antiplatelet therapy before PCI. Unfractionated heparin was administered to maintain the activated clotting time >250 seconds. It was the discretion of the operator to insert a temporary pacing lead, use a hemodynamic support device, and use intravascular ultrasound for the assessment of lesion morphology and stent expansion. Drug-eluting stents were implanted unless there was a contraindication to prolonged dual antiplatelet therapy. The typical burr-to-artery ratio was 0.5. However, if the lesion was severely stenotic and the reference vessel diameter was 3 mm, a 1.25-mm burr was initially used followed by larger burrs. The RA burr was tested and primed before insertion into the guiding catheter at 150,000 to 170,000 rpm while being mounted on the RotaWire. After all patients were treated with low-speed (80,000 rpm) atherectomy, high-speed (120,000 rpm) atherectomy was performed if the reference vessel diameter was at least 3 mm. Each pass was limited to 20 seconds. The duration of the dual antiplatelet therapy was at least 1 month for a bare metal stent and 1 year for a drug-eluting stent. The primary end point was the rate of 30-day major adverse cardiac and cerebrovascular events, defined as the composite of death, myocardial infarction (MI), target vessel revascularization (TVR), and stroke. MI was defined as recurrent symptoms with new ST-segment elevation or re-elevation of cardiac markers to at least twice the upper limit of normal. TVR was defined as repeat revascularization of the target vessel. The Academic Research Consortium definition of stent thrombosis was used.9 Procedural success was defined as residual stenosis 30% and thrombolysis in myocardial infarction grade 3 flow without death, emergency coronary artery bypass graft
Variable Anticoagulation Heparin Patients pretreated with clopidogrel Vascular access Transfemoral Transradial Maximum burr size (mm) OA device speed (revolutions/min) Low only, 80,000 Low and high, 80,000 and 120,000 Burr(s) per case Passes per case Type of stent Drug-eluting Bare metal Stents per case Vessels treated Temporary pacemaker Intra-aortic balloon pump Impella Extracorporeal membrane oxygenation Bail-out use of GP IIb/IIIa inhibitors Final TIMI flow 0-1 2 3 French size 6F 8F
RA (N¼67)
OA (N¼50)
67 (100%) 50 (100%) 65 (97%) 48 (96%) 66 (99%) 1 (1%) 1.5 0.1
47 (94%) 3 (6%) NA
NA NA 1.3 0.2 3.6 1.2
14 (28%) 36 (72%) NA 3.3 1.3
61 (91%) 7 (9) 1.4 0.6 1.3 0.2 5 (7%) 6 (9%) 2 (3%) 0 0
46 (92%) 4 (8) 1.5 0.4 1.3 0.3 0 2 (4%) 1 (2%) 1 (2%) 0
p-value
>0.9 0.9 0.7
0.7 0.9
0.7 0.9 0.2 0.3 0.9 0.9 >0.9 >0.9
0 0 0 0 67 (100%) 50 (100%) 0.6 63 (94%) 4 (6%)
50 (100%) 0
NA ¼ not applicable; OA ¼ orbital atherectomy; RA ¼ rotational atherectomy.
surgery, and/or PCI during the first 24 hours. Data on angiographic complications included perforation, dissection leading to less than thrombolysis in myocardial infarction grade 3 flow, and no reflow. Baseline demographic and procedural data and adverse clinical events were entered into a dedicated PCI database. Continuous variables are presented as mean SD and compared using the Student t test. Categorical variables are presented as percentages and compared using the chi-square test. A p value <0.05 was considered statistically significant. All data were processed with SPSS (version 20.0, SPSS-PC, Inc., Chicago, Illinois). Results Baseline demographic and procedural characteristics were well matched in both groups (Tables 1 and 2). Procedural success and angiographic complications were similarly low in both groups (Table 3). The primary end point was similar in the RA and OA groups (6% vs 6%, p >0.9), as were the individual end points of death (0% vs 2%, p ¼ 0.8), MI (6% vs 4%, p ¼ 0.7), TVR (0% vs 0%, p >0.9), and stroke (0% vs 0%, p >9) (Table 4). The 1 patient who died was a 43-year-old man who had cardiac arrest at home, had cardiopulmonary resuscitation, was intubated, and had enhanced
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Table 3 Angiographic complications Variable Procedural success Perforation Cardiac tamponade Dissection leading to less than TIMI grade 3 flow No reflow Stent loss
RA (N¼67)
OA (N¼50)
p value
67 (100%) 0 0 0
50 (100%) 1 (2%) 1 (2%) 0
>0.9 0.9 0.9 >0.9
5 (7%) 0
2 (4%) 0
0.4 >0.9
OA ¼ orbital atherectomy; RA ¼ rotational atherectomy. Table 4 Clinical Events at 30 days Variable
RA (N¼67)
OA (N¼50)
p value
Major adverse cardiac and cerebrovascular events Cardiac death Myocardial infarction Target vessel revascularization Stroke Stent thrombosis
4 (6%)
3 (6%)
>0.9
0 4 (6%) 0 0 0
1 (2%) 2 (4%) 0 0 0
0.8 0.7 >0.9 >0.9 >0.9
OA ¼ orbital atherectomy; RA ¼ rotational atherectomy.
extracorporeal membrane oxygenation initiated for cardiogenic shock despite being treated with 4 vasopressors. He underwent emergent orbital atherectomy of the left main and left anterior descending arteries because he was not a candidate for surgical revascularization. No patients experienced stent thrombosis. Discussion In the first analysis that compared clinical outcomes of OA with those of RA, the main finding of this study was that both devices were safe and effective for the treatment of severe CAC, with low rates of angiographic complications and adverse clinical outcomes. OA is faster to set up and easier to use because it does not require a nitrogen tank or a foot pedal to activate the device. The mechanism of action, centrifugal force, involves the crown spinning on the ViperWire and orbiting along the periphery of the vessel to debulk the plaque even further with each pass, whereas the RA burr has only 1 axis of rotation on the RotaWire and ablates a fixed diameter. The single axis of rotation also gives rise to the possibility of burr entrapment because it ablates only in the antegrade direction because of the lack of diamond coating on the proximal portion of the burr. In contrast, the OA ablates bidirectionally, lowering the risk of crown entrapment. The operator has fingertip control to switch from low speed to high speed to treat a larger vessel diameter because of ablation of a larger radius. With RA, an assistant is required to adjust the speed on the console, and the burr requires removal, exchange to a larger burr, and readvancement to progressively ablate more extensively for large vessels, increasing the procedural time and complexity of the case.
Larger burrs (1.75 mm) require 7F guiding catheters, whereas OA can be performed with a 6F guiding catheter for all cases. Because of the single axis of rotation, the burr is in constant contact with the plaque, resulting in thermal injury and platelet activation.10 The average particulate size with RA is 5 mm, and particles are released in boluses compared with the OA crown, which is in intermittent contact and continuously releases 2-mm particles, accounting for less distal embolization and the differences in the rates of slow/ no-flow with RA (2% to20%) and OA (0.9%).6,11e14 A disadvantage of RA is that the RotaWire needs to be exchanged for a workhorse wire. This may be explained by the fact that it has a 0.009-inch-diameter shaft and is not supportive enough to advance balloons and stents. The ViperWire, which has a 0.012-inch-diameter shaft, can support the advancement of balloons and stents. It can be cut with a scissor to approximate the length of a 160-cm guidewire to complete the PCI. Another potential advantage of OA may be in patients with angulated and eccentric lesions. The guidewire may lie preferentially against the wall of the vessel as opposed to the center, so-called guidewire bias, as a result of the contour of the vessel and the position of the guiding catheter. The burr may ablate asymmetrically on the RotaWire, possibly creating a “furrow” as opposed to debulking throughout the entire vessel. The angle of the vessel correlated with the pre-RA and post-RA luminal changes in the vertical axis but not the horizontal axis, validating the guidewire bias effect. Asymmetric CAC may further augment guidewire bias because the RotaWire may not guide the burr toward the calcified lesion, leading to inadequate ablation during advancement, increasing the risk of burr entrapment. In contrast, the orbital movement of the crown may overcome these issues because it ablates throughout the entire circumference of the vessel and is less influenced by the guidewire position or the eccentricity of the calcified plaque. Optical coherence tomography demonstrated that compared with RA, OA resulted in more modification of the plaque, including longer cuts and deeper dissections, which may explain the lower percentage of stent strut malapposition and a trend toward improved stent expansion.15 Rotational atherectomy may be preferred in treating aorto-ostial disease because OA is associated with suboptimal anchoring and stabilization of the proximal portion of the device while inside the guiding catheter. One technique to overcome this issue is to initially advance the crown distally followed by ablating the aorto-ostial lesion while pulling back the device proximally. Another technique is to firmly engage the tip in the calcified aorto-ostial lesion to constrain its orbit before activating the device. The ORBIT II trial excluded patients with vessels >4 mm.6 The 1.25-mm crown orbiting at high speed may not sufficiently modify plaque in larger vessels. A 2-mm RA burr might be preferred in these larger vessels. Patients with vessels <2.5 mm were also excluded because the 1.25-mm crown may be too large and increase the risk of perforation. The tip of the OA device does not have an ablative surface and may not traverse subtotally occluded calcified lesions. The ablative surface is at the tip of the burr and may be preferred to cross subtotal occlusions.
Coronary Artery Disease/RA Versus OA for Severely Calcified Coronary Lesions
This study was a small, retrospective one from a single center. The duration of follow-up was short. Quantitative coronary angiography and angiographic follow-up were not performed. Cardiac biomarkers were not routinely obtained on all patients after PCI. Atherectomy with the respective devices were performed at 2 different time intervals. Disclosure
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