Commentary: Dethrombosing Strategies and Endopharmacologic and Mechanical Techniques
- Volume 3 - Issue 3 - May/June 2006
- Posted on: 9/5/08
- 0 Comments
- 4681 reads
David E. Allie, MD
In this issue of VDM, Shammas has presented several algorithms regarding treatment of the spectrum of acute and chronic lower extremity ischemia with the emphasis refreshingly placed primarily on thrombus, platelets and “clot” management. I have referred to this as “endopharmacotherapy” in treating critical limb ischemia (CLI), and consider this tool just as important in achieving limb salvage as any of the recent novel device technologies we are now adding to our CLI “toolbox”.1 Endopharmacotherapy may even be more important when considering that ultimate limb loss often starts or ends up as minor distal tissue loss due to distal “infrapedal” digital vascular thrombosis and microvascular platelet aggregation that is essentially untreatable with any of our current device platforms. Furthermore, the realization that certainly microembolization and possibly macroembolization of athero or thromboembolic debris occur with every vascular intervention (including guidewire manipulation), should mandate interventionalists to consider novel pharmaceutical anticoagulation and antithrombus strategies in treating infrainguinal arterial occlusive disease, at least until “capillary-sized” distal protection devices (DPD) become available, which I do not foresee anytime soon.
The author nicely describes the acute, subacute, and chronic presentations of ischemia and algorithms for treatment. Considerable experience and expertise is generally required to optimize outcomes in these challenging patients with true CLI. Unfortunately, consensus definitions are still lacking today regarding the classification of lower-extremity ischemia, resulting in confusion and inconsistencies in treatments and the reporting of outcomes. Regardless, each algorithm appears to be well described and considered. The algorithm for acute limb ischemia (ALI) was built upon the platform of mechanical thrombectomy, utilizing the AngioJet system (Possis Medical Inc., Minneapolis, Minnesota) with or without the “Power-Pulse Spray” Technique, and is also our preferred method of treating ALI. There are a wealth of data supporting the safety and efficacy of utilizing the AngioJet in this setting, and advocating the concept of improved outcomes resulting from rapid removal of thrombus and return of flow in ischemic tissues.2,3 This is why we are proponents of treating the acutely ischemic leg like the acutely ischemic heart, hence the concept “treat ALI like ACS.”
The authors have appropriately identified the need for an optimal anticoagulation foundation utilizing bivalirudin (Angiomax, The Medicines Company, Parsippany, New Jersey) in each algorithm and identified the significant limitations of unfractionated heparin (UFH), which are magnified in the hyperthrombotic peripheral vascular disease (PVD) patient. I am in general agreement with algorithm 3A and 3B as the authors attempt to differentiate treatment in “subacute vs. chronic” CLI patients, where most of the inconsistencies and confusion exist around clinical care. Our endopharmacotherapy strategy, however, in each of those subsets or patients would include optimal periprocedural platelet inhibition with GP IIb/IIIa inhibitors regardless of clopidogrel. Every case is accompanied with some degree of distal microembolization, and therefore needs maximal perioperative protection from platelet microaggregation. It is our policy to have these patients on clopidogrel 75 mg a day for a one-week preprocedure, or immediately with a preprocedural load of 375 mg. Several recent reports support the safety and feasibility of this strategy in treating CLI like ACS even though randomized data are lacking.1,4,5 It must be mentioned that the recent report of the results of the Bilateral Lower Arterial Stenting Employing Reopro (BLASTER) trial, showing no difference in outcomes with abciximab (ReoPro, Eli Lilly and Company, Indianapolis, Indiana) in treating infrainguinal disease, was designed primarily for SFA endpoints treated with nitinol stents and not primarily for true CLI patients suffering primarily from severe infrapopliteal disease.6 These ACS patients undergoing percutaneous coronary intervention (PCI) that are known to benefit from GP IIb/IIIa inhibition include those patient with diabetes, small vessels, visible thrombus and complex lesions.1 This describes almost exactly the CLI patient population, hence a solid reason to apply this PCI strategy to the infrapopliteal vessels.
1. Allie DE, Hebert CJ, Lirtzman MD, et al. A Safety and feasibility report of combined direct thrombin and GP IIb/IIIa inhibition with bivalirudin and tirofiban in peripheral vascular disease intervention: Treating critical limb ischemia like acute coronary syndrome. J Invasive Cardiol 2005;17:427–432.
2. Ansel GM, George BS, Botti CF, et al. Rheolytic thrombectomy in the management of limb ischemia: 30 day results from a multicenter registry. J Endovasc Therapy 2002;9:395–402.
3. Kasirajan K, Gray B, Beavers F, et al. Rheolytic thrombectomy in the management of acute and subacute limb-threatening ischemia. J Vasc Interven Radiol 2001;12:413–421.
4. Krishna J. Rocha-Singh, Janiece Rutherford. Glycoprotein IIb-IIIa receptor inhibition with eptifibatide in percutaneous intervention for symptomatic peripheral vascular disease: The circulate pilot trial. Catheter Cardiovasc Interv 2005;66:470–473.
5. Shammas NW, Dippel EJ, Lemke JH, et al. Eptifibatide in peripheral vascular interventions: Results of the Inegrilin Reduces Inflammation in Peripheral Vascular interventions (INFLAME) trial. J Invasive Cardiol 2006;18:6–12.
6. Ansel GM, Silver MJ, Botti CF Jr, et al. Functional and clinical outcomes of nitinol stenting with and without abciximab for complex superficial femoral artery disease: A randomized trial. Catheter Cardiovasc Interv 2006;67:288–297.
7. Allie DE, Hebert CJ, Lirtzman MD, et al. Novel simultaneous combination chemical thrombolysis/rheolytic thrombectomy therapy for acute critical limb ischemia: The power-pulse spray technique. Catheter Cardiovasc Interv 2004;63:512–522.
8. U.S. Department of Health and Human Services. National Center for Health Statistics. National Hospital Discharge Survey: Annual Summary with Detailed Diagnosis and Procedure Data. Data from the National Hospital Discharge Survey. Series 13. 1983–2000.
9. Mayfield JA, Reiber GE, Maynard C, et al. Trends in lower limb amputation in Veterans Health Administration, 1989–1998. J Rehabil Res Dev 2000;37:23–30.
10. Yost, ML. Peripheral arterial disease: A report by the Sage Group. 2004; Vol. II.
11. Anonymous. Second european consensus document on chronic critical limb ischemia. Eur J Vasc Surg 1992;6:Suppl A:1–32.
12. Fisher RK, Harris PL. Epidemiological and economic considerations in the critically ischemic limb. Critical Limb Ischemia 1999:19–25.
13. Allie DE, Hebert CJ, Lirtzman MD, et al. Critical limb ischemia: A global epidemic. A critical analysis of current treatment unmasks the clinical and economic costs of CLI. EuroIntervention Journal 2005;1:75–184.