Tackling Below-the-Knee Disease in Critical Limb Ischemia
Critical limb ischemia (CLI) is a growing problem and challenging to adequately treat due to limited treatment modalities.1,2 The annual incidence of CLI is estimated at 220 to 1,000 new cases per 1,000,000 people, and the prevalence is estimated to be 1% of adults aged older than 40 years.3,4 Furthermore, approximately 10% of patients with peripheral artery disease (PAD) are estimated to have CLI,4 and between 5% and 20% of patients with asymptomatic PAD or intermittent claudication will progress to CLI over a 5-year period.5 The combination of an aging population burdened by increasing rates of cardiovascular risk factors and diabetes will lead to an increase in PAD and CLI prevalence. Even more concerning, CLI leads to adverse limb-related and systemic outcomes.2,6 A recent insurance registry of 41,882 patients with PAD in Germany found 4-year amputation rates among those with CLI and tissue loss to be 35% to 67%.7 The economic impact of PAD in the United States is significant, with annual health care costs estimated to be greater than $4 billion from Medicare data in 2001.8 The cornerstone of CLI treatment is revascularization to prevent limb loss and dysfunction, although the current paucity in clinical evidence renders the optimal revascularization strategy uncertain.2 With the advent of new technologies and devices, our options are improving.
The DEFINITIVE LE study demonstrated that directional atherectomy is a safe and effective treatment modality at 12 months in a diverse 800-patient population, including those with claudication or CLI.9 Furthermore, directional atherectomy was shown to be noninferior for treating PAD in patients with diabetes compared with those without diabetes, with a 1-year primary patency rate of 77% in diabetics compared to 78% in nondiabetics. Particularly in patients with CLI, the rate of freedom from major unplanned amputation of the target limb at 12 months in CLI patients was 95%. The primary patency rate of infrapopliteal vessels (average length, 5.5 cm) was 90% in the claudicant group and 78% in the CLI group (average length, 6 cm). The patency rates were similar in lesions longer than 10 cm. This established the safety and efficacy of directional atherectomy in infrapopliteal vessels. With a bailout stenting rate of < 4%, it also allowed interventionalists to treat with no metal left behind.9
Although directional atherectomy can be used as a stand-alone therapy, most often the luminal gain achieved after debulking is further enhanced with percutaneous balloon angioplasty (PTA). However, standard PTA causes multidirectional stress and trauma to the vessel wall leading to deformation and possible dissection (Figure 1).
These limitations of standard PTA are reduced with the Chocolate™* PTA balloon catheter (Medtronic), a special balloon design that incorporates a nitinol-constraining structure that creates pillows and grooves in the balloon to provide predictable, uniform, and atraumatic dilation (Figure 2). The pillows allow for vessel dilation without vessel scoring or cutting, while the grooves provide stress relief and plaque modification.
A 62-year-old man with a history of coronary artery disease, congestive heart failure, type 2 diabetes mellitus, hypertension, and dyslipidemia presented with a nonhealing ulcer of his left fifth toe (Rutherford class 5). Angiography revealed high-grade distal popliteal stenosis with single-vessel peroneal runoff (Figure 3A). The peroneal artery also had tandem high-grade lesions. We decided to treat these lesions with directional atherectomy with a HawkOne device (Medtronic, Figure 3B), followed by balloon angioplasty with a 2.5- X 100-mm Chocolate balloon (Figure 3C). Completion angiography revealed minimal residual stenosis with brisk flow (Figure 3D).
1. Fowkes FG, Rudan D, Rudan I, et al. Comparison of global estimates of prevalence and risk factors for peripheral artery disease in 2000 and 2010: a systematic review and analysis. Lancet. 2013;382:1329-1340.
2. Teraa M, Conte MS, Moll FL, Verhaar MC. Critical limb ischemia: current trends and future directions. J Am Heart Assoc. 2016;5:pii:e002938.
3. Norgren L, Hiatt WR, Dormandy JA, et al; TASC II Working Group. Inter-society consensus for the management of peripheral arterial disease (TASC II). J Vasc Surg. 2007;45(suppl S):S5-S67.
4. Nehler MR, Duval S, Diao L, et al. Epidemiology of peripheral arterial disease and critical limb ischemia in an insured national population. J Vasc Surg. 2014;60:686-695.e2.
5. Sigvant B, Lundin F, Wahlberg E. The risk of disease progression in peripheral arterial disease is higher than expected: a meta-analysis of mortality and disease progression in peripheral arterial disease. Eur J Vasc Endovasc Surg. 2016;51:395-403.
6. Dua A, Lee CJ. Epidemiology of peripheral arterial disease and critical limb ischemia. Tech Vasc Interv Radiol. 2016;19:91-95.
7. Reinecke H, Unrath M, Freisinger E, et al. Peripheral arterial disease and critical limb ischaemia: still poor outcomes and lack of guideline adherence. Eur Heart J. 2015;36:932-938.
8. Hirsch AT, Hartman L, Town RJ, Virnig BA. National health care costs of peripheral arterial disease in the Medicare population. Vasc Med. 2008;13:209-215.
9. McKinsey JF, Zeller T, Rocha-Singh KJ, et al. Lower extremity revascularization using directional atherectomy: 12-month prospective results of the DEFINITIVE LE study. JACC Cardiovasc Interv. 2014;7:923-933.
S. Hinan Ahmed, MD, FACC, FSCAI, FSVM
Division of Cardiology
San Antonio, Texas
Disclosures: Consultant for Medtronic; speaker’s bureau for Medtronic, Amgen Pharmaceuticals, Philips, and AstraZeneca.