Rotational Atherectomy in the Drug-Eluting Stent Era: A Single-Center Experience

ABSTRACT: Background. In heavily calcified lesions, rotational atherectomy (RA) improves procedural success and facilitates stent deployment. Reports on RA in the drug-eluting stent (DES) era are limited. The objective of this study was to determine the presenting characteristics, procedural and in-hospital clinical outcomes of patients who underwent RA at our institution in the DES era. Methods. Consecutive cases involving RA between January 1, 2004 and December 31, 2009 at a private, tertiary referral hospital were reviewed retrospectively. Results. A total of 158 patients (236 lesions) who underwent RA are described, including 112 patients (158 lesions) with subsequent DES implantation, 19 patients (28 lesions) with bare-metal stent (BMS) implantation, and 27 patients (50 lesions) with no stent. RA was utilized to modify heavily calcified plaque (84%), as bail-out therapy (16%), to preserve the patency of sidebranches (25%) and as debulking therapy for chronic total occlusion (13 lesions) and in-stent restenosis (7 lesions). DES were not placed in 46 patients (23%) due to reference vessel diameter 3.75 mm, inability to deliver DES, or desire to avert clopidogrel therapy. Angiographic and procedural success rates were significantly higher in the DES and BMS groups compared with the no stent group (angiographic success: 99.1% for DES versus 95% for BMS versus 63% for no stent; p Conclusion. In the DES era, RA remains utilized primarily to modify heavily calcified plaque. In unadjusted analysis, procedural success appears high with subsequent stent placement (DES or BMS) versus RA alone. However, 1 in 4 are not candidates for stent placement, and the lower procedural success rate in this population should be considered prior to embarking on RA. J INVASIVE CARDIOL 2011;23:133–139 Key words: atherectomy, drug-eluting stent, percutaneous coronary intervention, quantitative coronary angiography, calcification ——————————————————— Introduced in the early 1990s, rotational atherectomy (RA) failed to show consistent clinical benefit and resulted in a restenosis rate of 38% at 6 months.^1–4 However, RA has found a niche in improving procedural success rates in complex, heavily calcified lesions in which balloon angioplasty and stenting alone often result in failure or suboptimal stent expansion.^5,6 In heavily calcified lesions, adjuvant RA prior to bare-metal stent (BMS) deployment improved stent expansion,^7–10 but target lesion revascularization rates remained unacceptably high, ranging from 15–36% at 6–9 months.^10–13 Reports on RA in the drug-eluting stent (DES) era are limited, but indicate significantly improved target lesion revascularization rates in heavily calcified lesions, ranging from 2–10.6% at 6 months to 3 years.^12–16 Reports of RA in the DES era used focused inclusion criteria; that is, RA was indicated only for moderate to severe lesion calcification and all patients received a DES (some reports used a historical control group).^12–17 To our knowledge, no study in the DES era has examined overall use of RA, including patients treated with and without DES implantation and for indications other than severe calcification. Therefore, we sought to analyze patient characteristics, procedural characteristics and in-hospital clinical outcomes of patients who underwent RA between January 1, 2004 and December 31, 2009 to better define the use of RA in the DES era.

Methods

This was a retrospective analysis at Good Samaritan Hospital, a private, tertiary referral hospital, with approval from the Western Institutional Review Board. The cardiac catheterization database was searched to identify all cases involving RA between January 1, 2004 and December 31, 2009, during which time DES were commonly used. Cases were excluded if the intervention involved the left main coronary artery (reported separately), if the intervention involved the use of brachytherapy, or if the angiographic images could not be obtained. The use of RA and all other clinical decisions were at the discretion of the interventionalist. DES are routinely implanted during coronary interventions unless the clinical situation dictates otherwise (i.e., for lesions 3.75 mm, for patients with impending surgery or active bleeding, inability to deliver the DES, etc.). Patient demographics, medical history, procedural characteristics and in-hospital outcomes were recorded through a comprehensive chart review. Procedural and lesion characteristics were further defined using quantitative coronary angiography. Definitions. Patients who presented with a stress test suggesting myocardial ischemia without cardiac symptoms were labeled as having silent ischemia. Lesion calcification was defined prior to contrast injection as: severe if radiopacities were readily apparent without cardiac motion; moderate if radiopacities were apparent only with cardiac motion; mild if faint radiopacities were seen only with cardiac motion; and none if no radiopacities were seen.¹⁸ Lesions were classified according to American College of Cardiology/American Heart Association criteria.¹⁸ A lesion was defined as bifurcating if a branch > 1.5 mm with ostial disease originated within the stenosis and the branch was completely surrounded by stenotic portions of the parent vessel.¹⁸ A lesion that originated within 3 mm of the vessel origin was defined as ostial.¹⁸ Clinical outcomes were determined during the index hospitalization. Major adverse cardiac events (MACE) were defined as death, target vessel revascularization, Q-wave myocardial infarction, or non-Q wave myocardial infarction (new creatine kinase elevation above two times the upper limit of normal). Angiographic success was defined as Quantitative coronary angiography. Quantitative coronary angiography was performed using MDQM-QCA (Medcon Quantitative Measurements-Quantitative Coronary Arteriography; Medcon Limited, Tel Aviv, Israel) edge-detection software. Measurements were made using the view with the highest degree of stenosis and the least amount of foreshortening. A preintervention angiogram was used to determine lesion length. Reference vessel diameter was determined using a post-intervention image by taking the mean of the angiographically normal-appearing segments proximal and distal to the lesion. If normal-appearing proximal and distal segments were not available (e.g., ostial lesions), then estimates were made using the available segments (e.g., for ostial lesions, the reference vessel diameter was equal to or slightly greater than the normal-appearing distal segment). Minimal luminal diameter (MLD) was determined up to three times: 1) preintervention; 2) post-RA (and balloon angioplasty if balloon angioplasty was done); and 3) post-stenting (if a stent was placed). The percent diameter stenosis at each instance was determined by dividing the MLD at that instance by the reference vessel diameter. Acute gain was defined as post-intervention MLD minus pre-intervention MLD. Statistics. Results are reported as means ± standard deviations or percentages of the total. For statistical comparison, cases were stratified into three groups based on stent deployment: DES, BMS, or no stent. Statistical analysis was done using SAS, version 9.1 (SAS Institute, Inc., Cary, North Carolina). Statistical significance was considered a p-value or F-value Results A total of 268 cases involving RA were identified between January 1, 2004 and December 31, 2009. After excluding cases involving an intervention on the left main coronary artery (n = 31), brachytherapy (n = 10), or in which the angiographic images could not be obtained (n = 69), a total of 158 cases (involving 236 lesions) were included. DES were implanted in 112 patients (158 lesions), BMS were placed in 19 patients (28 lesions), and no stent was placed in 27 patients (50 lesions) (Table 1). The patients were elderly (72.3 ± 11 years) and comorbidities were common, including hypertension in 89%, diabetes mellitus in 46% and hyperlipidemia in 69% (Table 1). Compared with the DES group, the BMS group had lower ejection fractions (ejection fraction ≤ 35% was 21% with DES versus 53% with BMS; p = 0.0163), and the no stent group had a smaller mean reference vessel diameter (2.54 ± 0.46 mm versus 2.22 ± 0.66 mm; p Indications for RA. RA was indicated for plaque modification in the setting of moderate to severe calcification in 84% of lesions, but calcification was not the sole indication for RA in this series (Table 2). In 60 patients (25%), RA was deployed to preserve the patency of a sidebranch. RA was deployed in 13 chronic total occlusions and 7 in-stent restenoses, all of which achieved angiographic and procedural success. In 37 lesions (16%; 34 severe and 2 moderate calcifications), RA was not planned but was utilized as “bail-out” therapy after a prior attempt at PCI had failed or an angioplasty balloon could not be delivered to the lesion (some lesions had multiple indications for RA, so the sum of indications is > 100%). DES implantation. Most patients were treated with a stent (80%), and most stents were DES (71% of all patients). DES were avoided due to clinical factors in 37 patients (23%) for reasons that included a vessel diameter 3.75 mm, impending surgery and a high risk for bleeding (Table 3). In 9 patients (6%), DES implantation was attempted but failed due to an inability to deliver the stent to the lesion, vessel dissection (BMS used to avoid delayed endothelialization) or vessel perforation (no stent placed to avoid increased bleeding risk with clopidogrel). Thus, DES were successfully implanted in 94% of patients in whom DES placement was attempted despite severe calcification and lesion complexity. Procedural and in-hospital outcomes. Angiographic success and procedural success were achieved significantly more frequently in the DES and BMS groups compared with the no stent group (angiographic success: 99.1% versus 95% versus 63%, respectively; p Procedural characteristics. Thirty-three percent of patients were treated with multiple burrs (mean, 1.40 ± 0.62 burrs) (Table 5). Final burr size was 1.50 ± 0.22 mm and was similar among the three groups. The final burr-to-vessel ratio was larger in the no stent group (0.71 ± 0.17) compared to each of the stent groups (DES, 0.60 ± 0.11; BMS, 0.50 ± 0.09). Balloon angioplasty was utilized less often and with a lower maximum pressure in the no stent group (70%; 7.0 ± 4.1 atm) compared with each of the stent groups (DES, 92% and 9.9 ± 4.0 atm; BMS, 93% and 11.4 ± 4.8 atm). Eighty-four of 186 stented lesions (45%) underwent post-dilation at a mean maximum inflation pressure of 15.8 ± 3.9 atm. Utilization of intravascular ultrasound was low (3.8%) and procedure times were long (96 ± 31 minutes). Quantitative coronary angiography. Reference vessel diameter differed significantly between each group: 2.54 ± 0.46 mm in the DES group, 3.24 ± 1.07 mm in the BMS group, and 2.22 ± 0.66 mm in the no stent group; Table 5). Similarly, MLD measured initially, after RA, and after stenting differed between groups. Percent diameter stenosis was similar between groups before and after intervention, except that the no stent group reached a smaller percent diameter stenosis after RA and balloon angioplasty compared with each of the stent groups. In these complex, heavily calcified lesions, RA combined with stenting achieved a total acute gain of 1.58 ± 0.56 mm, and reduced an initial percent diameter stenosis of 68 ± 14% to 8 ± 12%. A small degree of vasoconstriction was frequently observed following RA as suggested by the mean minimal luminal diameter after RA and PTCA (1.47 ± 0.39 mm) being smaller than the mean burr size (1.50 ± 0.22 mm). Procedural complications. In this series with 37 bifurcation lesions (15%) and 66 ostial lesions (28%), RA was deployed specifically to preserve sidebranch patency in 60 lesions. Sidebranch patency was preserved in 59 of these 60 lesions (98.3%). Overall, procedural complications included coronary artery dissection in 4.2%, perforation in 0.8%, sidebranch occlusion in 0.4% and acute stent thrombosis in 0% (Table 4). Both perforations were contained (1 small, 1 moderate in size) and treated successfully with prolonged balloon inflations. Six of the 9 vessel dissections were small (type A or B). Three vessel dissections were type E or F and resulted in a Q-wave myocardial infarction, an emergency CABG surgery, and a death. The type F dissection was attributed to the guidewire and 1 of the type E dissections was attributed to balloon angioplasty. Occlusive coronary spasm occurred in 2.1% and marked no reflow was noted in 2.1%. Two cases each of occlusive spasm and no reflow correlated with significant hypotension and/or bradycardia that responded to medical therapy.

Discussion

This study sought to describe the contemporary use of RA in the DES era. This study confirms that RA is used primarily in complex lesions with moderate to severe calcification where the operators felt balloon angioplasty and stenting alone would not be sufficient. Additionally, this real-world experience reflects the use of RA to preserve the patency of sidebranches in bifurcation and ostial lesions and to debulk large plaque burdens in chronic total occlusions and in-stent restenoses. In the DES era, RA is followed by DES deployment in approximately 3 of 4 patients, whereas 1 in 4 patients are treated with BMS or no stent due to clinical and procedural characteristics, including vessel size. In unadjusted analyses, angiographic and procedural success rates are higher when a stent (either DES or BMS) is placed. However, those in whom no stent was placed faced greater angiographic and procedural failure rates. Anticipated ability to place a stent should be taken into account prior to embarking on RA. The literature describes the use of RA in heavily calcified lesions to improve procedural success^5,6 and improve stent expansion.^4,7–10 RA enabled DES deployment in nondilatable, calcified lesions.^16,17 In heavily calcified lesions, RA and DES deployment results in target lesion revascularization rates ranging from 2–10.6% at 6 months to 3 years, which is significantly better than RA and BMS.^12–16 Reports on RA and DES focused on calcified lesions.^12–16 RA to modify calcified plaque. RA was employed to modify calcified plaque in 199 lesions (84%) in this series and successfully facilitated DES implantation in 112 of 121 attempts (92.6%). When utilized to facilitate stent implantation in heavily calcified lesions, RA is performed with a relatively small burr-to-vessel ratio (0.5–0.6) because maximizing luminal gain is not necessary.^8,11,13,17 Rather, the objective is to alter the compliance of a calcified lesion in order to optimize stent expansion. In heavily calcified, eccentric lesions, stent expansion is optimized and more symmetric following adjuvant RA to reduce the lesion’s rigidity and eccentricity.⁹ The benefit of RA cannot be measured by its corresponding acute luminal gain, which was 0.67 ± 0.42 mm in this series. Instead, the impact of RA is reflected in the residual percent stenosis after stenting (8 ± 12% in this series), which would not have been possible without plaque modification from RA. Our operators had a low threshold for using RA to treat heavily calcified lesions. Had RA not been planned, percutaneous intervention by way of stent deployment may have failed in a substantial portion of these calcified lesions, meaning the percentage of “bail-out” procedures would have been higher than reported (37 lesions; 16%). The greatest clinical impact of RA may be enabling percutaneous intervention in lesions that may otherwise require surgical revascularization. Of note, a burr-to-vessel ratio 19 RA may also improve drug delivery to the subintimal tissue by limiting trauma to the DES coating during deployment in rigid, calcified lesions.¹³Indications for RA. RA was indicated for moderate to severe calcification in 84% of patients in this series. However, in contrast to other reports of RA and DES, this real-world experience also included the use of RA to preserve sidebranch patency in 60 lesions (25%), and to debulk large plaque burdens in 13 chronic total occlusions and 7 in-stent restenoses. Considering the current trend toward the exclusive use of balloon angioplasty and stenting and less use of other modalities in percutaneous coronary interventions, it is important to note these indications for RA in lesion subsets that pose challenges to balloon angioplasty and stenting. RA to prevent sidebranch occlusion. In bifurcation and ostial lesions, RA preserved the patency of sidebranches by debulking large plaque burdens and limiting the “snow plow” effect whereby balloon or stent expansion shifts plaque from one vessel into another vessel, compromising its patency.^20,21 In this series, RA successfully preserved sidebranch patency in 59 of 60 lesions (98.3%). Often, the parent vessel with a bifurcation lesion was treated with routine DES implantation, whereas the smaller “daughter” branch with ostial disease was treated with provisional stenting. This technique is reflected in the significantly higher portion of ostial lesions in the no stent group and the trend toward increased bifurcation lesions in the DES group (Table 1). Drug-eluting stent implantation following RA. In the DES era, and in this series, DES are routinely implanted during coronary intervention unless the clinical situation dictates otherwise. Indeed, RA was followed by DES implantation in 112 patients (71%) in this series. DES implantation was attempted but failed in an additional 9 patients (6%) due to vessel perforation (n = 1), dissection (n = 2), or an inability to deliver the stent because of severe calcification (n = 5). A BMS was planned in 14 patients (9%) and no stent was planned in 23 patients (15%). DES were avoided because of a reference vessel diameter 3.75 mm (DES are not produced this large), or to avert the need for clopidogrel therapy in patients with impending surgery or at high risk for bleeding. Angiographic success and in-hospital outcomes. In accordance with the literature, angiographic success (defined as Study limitations. The treatment of “secondary” lesions impacted these results. RA was indicated for the majority of secondary lesions due to calcification, but the degree of stenosis of many secondary lesions would not have prompted intervention without their proximity to the culprit lesion. Thus, the inclusion of secondary lesions reduced what would have been a higher initial percent diameter stenosis. All 4 class A lesions were secondary lesions. As all patients received RA, this was not a study of whether RA is superior to other approaches in these patients, but rather a descriptive study of the real-world outcomes in those who receive RA in the current era. Thus, no statements can be made regarding the merits of RA over alternate approaches. It is uncertain whether the results of this retrospective analysis at a single center will translate prospectively to interventional practice in the community. A total of 69 patients were excluded because the angiographic images could not be obtained. Consequently, this relatively small number of patients may not be representative of the larger cohort or of larger patient populations. Differences in outcomes were not adjusted for baseline or angiographic differences. Long-term follow up was not investigated, where DES are expected to demonstrate benefit over BMS and over RA alone.

Conclusion

In the DES era, it appears that RA is used primarily in patients with moderate to severe calcification, but other indications were also noted. In the current DES era, approximately 3 of 4 patients treated with RA subsequently received a DES and were met with high angiographic and procedural success; however, DES were avoided or not deliverable in approximately 1 of 4 patients. Importantly, these latter patients had significantly lower angiographic and procedural success rates. Anticipated ability to place a stent (either BMS or DES) should therefore be considered prior to embarking on RA in the current era.

References

1. Mauri L, Reisman M, Buchbinder M, et al. Comparison of rotational atherectomy with conventional balloon angioplasty in the prevention of restenosis of small coronary arteries: Results of the Dilatation vs Ablation Revascularization Trial Targeting Restenosis (DART). Am Heart J 2003;145:847–854.
2. vom Dahl J, Dietz U, Haager PK, et al. Rotational atherectomy does not reduce recurrent in-stent restenosis: Results of the angioplasty versus rotational atherectomy for treatment of diffuse in-stent restenosis trial (ARTIST). Circulation 2002;105:583–588.
3. Warth DC, Leon MB, O'Neill W, et al. Rotational atherectomy multicenter registry: Acute results, complications and 6-month angiographic follow-up in 709 patients. J Am Coll Cardiol 1994;24:641–648.
4. Tran T, Brown M, Lasala J. An evidence-based approach to the use of rotational and directional coronary atherectomy in the era of drug-eluting stents: When does it make sense? Catheter Cardiovasc Interv 2008;72:650–662.
5. MacIsaac AI, Bass TA, Buchbinder M, et al. High speed rotational atherectomy: Outcome in calcified and noncalcified coronary artery lesions. J Am Coll Cardiol 1995;26:731–736.
6. Kiesz RS, Rozek MM, Ebersole DG, et al. Novel approach to rotational atherectomy results in low restenosis rates in long, calcified lesions: Long-term results of the San Antonio Rotablator Study (SARS). Catheter Cardiovasc Interv 1999;48:48–53.
7. Whitbourn RJ, Sethi R, Pomerantsev EV, Fitzgerald PJ. High-speed rotational atherectomy and coronary stenting: QCA and QCU analysis. Catheter Cardiovasc Interv 2003;60:167–171.
8. Henneke KH, Regar E, Konig A, et al. Impact of target lesion calcification on coronary stent expansion after rotational atherectomy. Am Heart J 1999;137:93–99.
9. Hoffmann R, Mintz GS, Popma JJ, et al. Treatment of calcified coronary lesions with Palmaz-Schatz stents. An intravascular ultrasound study. Eur Heart J 1998;19:1224–1231.
10. Hoffmann R, Mintz GS, Kent KM, et al. Comparative early and nine-month results of rotational atherectomy, stents, and the combination of both for calcified lesions in large coronary arteries. Am J Cardiol 1998;81:552–557.
11. Moussa I, Di Mario C, Moses J, et al. Coronary stenting after rotational atherectomy in calcified and complex lesions. Angiographic and clinical follow-up results. Circulation 1997;96:128–136.
12. Rathore S, Matsuo H, Terashima M, et al. Rotational atherectomy for fibro-calcific coronary artery disease in drug eluting stent era: Procedural outcomes and angiographic follow-up results. Catheter Cardiovasc Interv 2010;75:919–927.
13. Khattab AA, Otto A, Hochadel M, et al. Drug-eluting stents versus bare metal stents following rotational atherectomy for heavily calcified coronary lesions: Late angiographic and clinical follow-up results. J Interv Cardiol 2007;20:100–106.
14. Vaquerizo B, Serra A, Miranda F, et al. Aggressive plaque modification with rotational atherectomy and/or cutting balloon before drug-eluting stent implantation for the treatment of calcified coronary lesions. J Interv Cardiol 2010;23:240–248.
15. Mezilis N, Dardas P, Ninios V, Tsikaderis D. Rotablation in the drug eluting era: Immediate and long-term results from a single center experience. J Interv Cardiol 2010;23:249–253.

16. Clavijo LC, Steinberg DH, Torguson R, et al. Sirolimus-eluting stents and calcified coronary lesions: Clinical outcomes of patients treated with and without rotational atherectomy. Catheter Cardiovasc Interv 2006;68:873–878.
17. Schluter M, Cosgrave J, Tubler T, et al. Rotational atherectomy to enable sirolimus-eluting stent implantation in calcified, nondilatable de novo coronary artery lesions. Vascular Disease Management 2007;4:63–69.
18. Kini AS. Coronary angiography, lesion classification and severity assessment. Cardiol Clin 2006;24:153–162.
19. Safian RD, Feldman T, Muller DW, et al. Coronary angioplasty and Rotablator atherectomy trial (CARAT): Immediate and late results of a prospective multicenter randomized trial. Catheter Cardiavasc Interv 2001;53:213–220.
20. Sharma SK, Bhalla N, Dangas G, et al. Rotational atherectomy prior to coronary stenting prevents sidebranch occlusion (abstract). J Am Coll Cardiol 1997:498A.
21. Tan RP, Kini A, Shalouh E, et al. Optimal treatment of nonaorto ostial coronary lesions in large vessels: Acute and long-term results. Catheter Cardiovasc Interv 2001;54:283–288.

——————————————————— From the ^*Heart Institute and ^§Department of Cardiology, Good Samaritan Hospital, Los Angeles, California and the ^£Department of Internal Medicine, Division of Cardiovascular Medicine, Keck School of Medicine at the University of Southern California, Los Angeles, California. Disclosures: An educational grant from Boston Scientific Corporation was used to support this project. Dr. Burstein is on the speakers bureau for Abbott Vascular and Boston Scientific; Dr. Shavelle has received grants from Abbott Vascular and Abiomed and speaker honoraria from Abbott Vascular; Dr. Mayeda has received speaker honoraria from Boston Scientific. Manuscript submitted September 29, 2010, provisional acceptance given November 9, 2010, final version accepted January 18, 2011. Address for correspondence: Bryan Schwartz, MD, Heart Institute, Good Samaritan Hospital, 1225 Wilshire Blvd., Los Angeles, CA 90017-2395. E-mail: bschwartz15@hotmail.com