Atherectomy – Safe for All Ages?

Age is a significant risk factor for peripheral artery disease (PAD), a condition estimated to affect up to 1 in 5 people over the age of 60 and 1 in 4 people over the age of 80.¹ A number of structural and functional changes occur in aged vessels, contributing to the rapid increase in PAD prevalence over time. Decreased elastin coupled with increased intima-media thickness, collagen cross-linking, medial calcium deposits, and endothelial dysfunction² are some examples of peripheral vascular changes that occur with aging that result from a life-long continuum of events.

Claudication symptoms in the elderly can be challenging to manage conservatively given comorbidities and polypharmacy that may limit the efficacy of exercise programs and pharmacologic treatments. Furthermore, the medical complexity of older patients and the high frequency of concomitant ischemic heart disease often render the risks of surgical revascularization and anesthesia unfavorable. Endovascular technological advances have therefore made the minimally invasive percutaneous approach the treatment of choice for most in the initial management of symptomatic patients. Atherectomy is a procedure performed to remove or “debulk” the atherosclerotic plaque from diseased arteries, with orbital atherectomy being advantageous in densely calcified vessels. Atherectomy affords an opportunity to minimize plaque shift while generally avoiding stent placement, or prevents incomplete stent expansion when adjuvant stenting is deemed necessary. Recently, atherectomy device utilization has been increasing despite a lack of non-industry funded, large clinical trials and a paucity of comparative effectiveness research regarding the use of the four Food and Drug Administration (FDA)-approved devices.³  

Accordingly, the 2013 American College of Cardiology Foundation/American Heart Association Practice Guidelines regard the utilization of adjuvant techniques, including atherectomy, a class-IIb indication for routine use in femoral, popliteal, and infrapopliteal arterial lesions and a class-IIa indication when used as a bail-out strategy due to a failed or suboptimal result after balloon dilation.⁴ The latter becomes a very common scenario in aged, diffusely diseased vessels with less vascular compliance and unyielding calcific disease. Thus, it would be important to investigate how atherectomy fares in older patients. Despite a paucity of data in older patients from randomized controlled trials, data regarding short-term and long-term outcomes with atherectomy devices can be obtained from a variety of national, prospective registries.

In the August 2015 issue of the Journal of Invasive Cardiology, Lee et al analyzed nearly 3000 patients and 4500 infrainguinal lesions from the series of CONFIRM registries with regard to angiographic complications when stratified by age, in older (≥75 years) versus younger (<75 years) patients.⁵ These combined registry data mimic real-world experience, with the younger patient group having a higher proportion of males, smokers, and diabetics. Older PAD patients (mean age, 81 years vs 65 years) were more likely to present with limb ischemia (higher baseline Rutherford class), have longer lesions (75 mm vs 70 mm), and be treated for below-the-knee lesions, and had a trend toward more “severe” calcified lesions (46% vs 43%; P=.07). The main findings were a similar rate of composite adverse periprocedural events, dissection, vessel closure, spasm, and embolism. However, older patients had significantly less thrombus formation, but a higher rate of perforation (1.2% vs 0.4%; P=.01).

These data provide further reassurance that orbital atherectomy is safe, given the overall low event rates in an all-comer population. Many of the recorded events were clinically inconsequential, such as non-flow limiting dissections and spasm. It is likely that more complex and diffusely diseased lesions in elderly patients were not routinely included in this registry, given the relatively short length of lesions treated and minimal difference in degree of calcification in the two age groups. Despite these limitations, age was not a predictor of composite angiographic complications after adjustment, supporting the procedural safety of atherectomy in patients of all ages. Long-term patency rates and clinical efficacy in the elderly, however, need to be further examined.

A major limitation of the current analysis, as discussed by the authors, is the lack of core laboratory adjudication of angiographic data. In addition, given the lack of standardized definitions of calcification in PAD trials, operators subjectively categorized calcium severity. This allows for potential selection, observational, and reporting bias. Future studies should incorporate the recently introduced consensus definitions by the Peripheral Academic Research Consortium (PARC)⁶ to help mitigate some of these limitations. Severe calcification can now be uniformly defined as the presence of calcium on both sides of the vessel at the same location (>180°) while spanning greater than one-half of the total lesion length.

Other technical and procedural factors associated with atherectomy use may differentially impact outcomes in the elderly. For example, since atherectomy use may prolong the procedure duration due to set-up and atherectomy run times, as well as the need for distal embolic protection placement/retrieval, the elderly could be more susceptible to side effects from longer sedation, pain control, or contrast-induced nephropathy. On the other hand, atherectomy allows for lower balloon inflation pressures and results in <10% frequency of adjunctive stenting. Unfortunately, there have been no head-to-head comparisons between the currently available atherectomy devices. Rotational, directional (extractional), and excimer-laser atherectomy systems have independently been shown to have comparable adverse event rates in a wide range of patient ages.^7-9 Therefore, a class effect likely exists with regard to safety of atherectomy device utilization in older patients. Operator choice will likely be influenced then by other technical factors, such as the need for distal embolic protection placement, ease of use, availability, capital equipment-related costs, and training of support staff.

In summary, the overall quality of care delivered to our aging population is improving due to continued innovation in device technology. Despite older patients having unfavorable baseline characteristics, Lee et al have shown that orbital atherectomy results in similar composite rates of adverse events when compared with a younger population. We should continue to think broadly in terms of alternative strategies for improving procedural and clinical outcomes in older patients. Bleeding avoidance strategies, such as using lower-profile sheaths and careful selection and monitoring of periprocedural antithrombotic pharmacotherapy and long-term antiplatelet therapies, are essential. Future studies in the elderly should also focus on examining the safety of same-day discharge versus an overnight stay after peripheral intervention. Importantly, additional studies are required to identify a durable and cost-effective strategy for treatment of complex, calcified lesions, which may include a combination of atherectomy and emerging technologies, such as drug-eluting balloons and possibly bioabsorbable stent platforms.

References

1. Peripheral arterial disease fact sheet. Centers for Disease Control and Prevention. Available at https://www.cdc.gov/DHDSP/data_statistics/fact_sheets/fs_PAD.htm. Updated July 26, 2013. Accessed April 6, 2015.
2. Swaminathan RV, Alexander KP. Pulse pressure and vascular risk in the elderly: associations and clinical implications. Am J Geriatr Cardiol. 2006;15:226-232.
3. Ambler GK, Radwan R, Hayes PD, Twine CP. Atherectomy for peripheral arterial disease. Cochrane Database Syst Rev. 2014;3:CD006680.
4. Anderson JL, Halperin JL, Albert NM, et al. Management of patients with peripheral artery disease (compilation of 2005 and 2011 ACC/AHA guideline recommendations): a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation. 2013;127(13):1425-1443.
5. Lee MS, Beasley R, Adams GL. Impact of advanced age on procedural and acute angiographic outcomes in patients treated for peripheral artery disease with orbital atherectomy: a CONFIRM registries subanalysis. J Invasive Cardiol. 2015;27:381-386.
6. Patel MR, Conte MS, Cutlip DE, et al. Evaluation and treatment of patients with lower-extremity peripheral artery disease: consensus definitions from Peripheral Academic Research Consortium (PARC). J Am Coll Cardiol. 2015;65:931-941.
7. Minko P, Katoh M, Jaeger S, Buecker A. Atherectomy of heavily calcified femoropopliteal stenotic lesions. J Vasc Interv Radiol. 2011;22:995-1000. 
8. Zeller T, Krankenberg H, Steinkamp H, et al. One-year outcome of percutaneous rotational atherectomy with aspiration in infrainguinal peripheral arterial occlusive disease: the multicenter pathway PVD trial. J Endovasc Ther. 2009;16:653-662.
9. Dave RM, Patlola R, Kollmeyer K, et al. Excimer laser recanalization of femoropopliteal lesions and 1-year patency: results of the CELLO registry. J Endovasc Ther. 2009;16:665-675.

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From the Division of Cardiology, Weill Cornell Medical College, New York Presbyterian Hospital, New York, New York.

The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Feldman reports consultant/speaker fees for Abbott Vascular, Eli Lilly/Daiichi Sankyo, Bristol Myers Squibb, and Pfizer. Dr Swaminathan reports no conflicts of interest regarding the content herein.

Address for correspondence: Dmitriy N. Feldman, MD, Director, Endovascular Services, Associate Professor of Medicine, Weill Cornell Medical College, New York Presbyterian Hospital, Department of Medicine, Greenberg Division of Cardiology, 520 East 70th Street, Starr-434 Pavilion, New York, NY 10021. Email: dnf9001@med.cornell.edu