Lawrence A. Garcia

Stent Thrombosis After Successful Sirolimus-Eluting Stent Implantation

Background—Stent thrombosis (ST) is a rare but devastating complication of coronary stent implantation, occurring in 0.5% to 1.9% of patients with bare metal stents. The incidence of ST with drug-eluting stents is less well studied, particularly among patients outside of clinical trials. Methods and Results—The aim of this study was to evaluate the incidence and potential risk factors for ST in patients receiving sirolimus-eluting stents (SES) in the “real world” after commercial release in the United States in April 2003. All 652 patients who underwent SES implantation (776 lesions treated) at our institution between April and October 2003 were followed up prospectively after the procedure (median follow-up 100 days). During that period, 7 patients (1.1%, 95% CI 0.4% to 2.2%) developed ST within a range of 2 to 13 days, and 1 patient had an ST-elevation myocardial infarction on day 39 with evidence of thrombus within the SES at angiography. Patients with an ST had significantly smaller final nominal balloon diameters (2.75 versus 3.00 mm, P =0.04), and in 4 (57%) of the 7 patients with ST versus 1.7% of patients without ST (P <0.001), antiplatelet therapy had been discontinued after the procedure. Among the ST patients, 1 died and 5 had myocardial infarctions. Conclusions—In this single-center experience, the incidence of ST after SES implantation was ≈1%, which is within the expected range of bare metal stents. The discontinuation of antiplatelet therapy was strongly associated with the development of ST in this patient population.

Midterm Outcomes from the TALON Registry: Treating Peripherals with SilverHawk: Outcomes Collection

Purpose: To determine midterm clinical outcomes among patients with lower extremity peripheral arterial disease who underwent revascularization with catheter-based plaque excision (PE). Methods: Between August 2003 and February 2005, 19 institutions participating in the observational, nonrandomized, multicenter TALON registry enrolled 601 consecutive patients (353 men; mean age 70±11, range 36–98) with 1258 symptomatic lower extremity atherosclerotic lesions (748 limbs) treated by plaque excision with the SilverHawk catheter. Approximately 50% of the patients had diabetes, and nearly one third of the procedures were indicated for Rutherford ischemia category ≥4. Mean lesion lengths above and below the knee, respectively, were 62.5±68.5 mm (interquartile range [IQR], 20.0–80.0) and 33.4±42.7 mm (IQR 15.0–37.5). The primary endpoints of the study were target lesion revascularization (TLR) at 6 and 12 months. Results: The device achieved ≤50% residual diameter stenosis in 94.7% of lesions; procedural success was 97.6%. Nearly half (41.9%) of the procedures involved PE of ≥2 lesions. Nearly three quarters (73.3%) of the lesions did not require adjunctive therapy, and stent placement following PE occurred in only 6.3% of lesions. The 6- and 12-month rates of survival free of TLR were 90% and 80%, respectively. Rates of TLR were similar among patients with diabetes (11%) and without diabetes (9%). In the multivariate analysis, significant predictors of TLR at 6 months were a history of MI or coronary revascularization (HR 5.49, 95% CI 1.87 to 16.10, p=0.0008), multiple (≥2) lesions (HR 1.37, 95% CI 1.11 to 1.70, p=0.0019), and increasing Rutherford category (HR 1.84, 95% CI 1.28 to 2.65, p=0.0003). Lesion length >50 mm was associated with a 2.9-fold increased risk for TLR (HR 2.88, 95% CI 1.18 to 7.01, p=0.012); lesion length >100 mm was associated with a 3.3-fold increase in TLR (HR 3.32, 95% CI 1.15 to 9.56, p=0.016). Conclusion: In patients undergoing revascularization for lower extremity atherosclerotic disease, catheter-based PE achieves favorable procedural success and avoids the need for repeat revascularization at midterm follow-up. These findings support PE as a primary endovascular therapy for patients undergoing lower extremity arterial revascularization.

Lower extremity revascularization using directional atherectomy: 12-month prospective results of the DEFINITIVE LE study.

OBJECTIVES The aim of this study was to assess the safety and effectiveness of directional atherectomy (DA) for endovascular treatment of peripheral arterial disease (PAD) in infrainguinal arteries in patients with claudication or critical limb ischemia. BACKGROUND To date, no prospective, multicenter, independently-adjudicated study has evaluated the effectiveness and durability of DA in the treatment of PAD. Previous DA studies have not been prospectively powered to evaluate any differences in outcomes in patients with and without diabetes. METHODS DEFINITIVE LE (Determination of EFfectiveness of the SilverHawk(®) PerIpheral Plaque ExcisioN System (SIlverHawk Device) for the Treatment of Infrainguinal VEssels / Lower Extremities) prospectively enrolled subjects at 47 multinational centers with an infrainguinal lesion length up to 20 cm. Primary endpoints were defined as primary patency at 12 months for claudicants and freedom from major unplanned amputation for critical limb ischemia (CLI) subjects. A pre-specified statistical hypothesis evaluated noninferiority of primary patency in diabetic versus nondiabetic claudicants. Independent angiographic and sonographic core laboratories assessed outcomes, and events were adjudicated by a clinical events committee. RESULTS A total of 800 subjects were enrolled. The 12-month primary patency was 78% (95% confidence interval: 74.0% to 80.6%) in claudicants, with a 77% rate in the diabetic subgroup versus 78% in the nondiabetic subgroup (noninferior, p < 0.001). The rate of freedom from major unplanned amputation of the target limb at 12 months in CLI subjects was 95% (95% confidence interval: 90.7% to 97.4%). Periprocedural adverse events included embolization (3.8%), perforation (5.3%), and abrupt closure (2.0%). The bail-out stent rate was 3.2%. CONCLUSIONS The DEFINITIVE LE study demonstrated that DA is a safe and effective treatment modality at 12 months for a diverse patient population with either claudication or CLI. Furthermore, DA was shown to be noninferior for treating PAD in patients with diabetes compared with those without diabetes. (Study of SilverHawk/TurboHawk in Lower Extremity Vessels [DEFINITIVE LE]; NCT00883246).

Epidemiology and Pathophysiology of Lower Extremity Peripheral Arterial Disease

Peripheral arterial disease (PAD), a major cause of disability, loss of work, and lifestyle changes in the United States, is defined as obstruction of blood flow into an arterial tree excluding the intracranial or coronary circulations. PAD is mostly silent in its early stages, but when lesion obstruction exceeds 50%, it may cause intermittent claudication with ambulation. Further disease progression typically leads to rest pain or frank tissue loss. However, some patients may remain asymptomatic with severe disease because of extensive collateralization in the lower extremity. Estimates of the prevalence of intermittent claudication vary by population, from 0.6% to nearly 10%; the rate increases dramatically with age. Approximately 20% to 25% of patients will require revascularization, while fewer than 5% will progress to critical limb ischemia. Limb loss, although rare, is associated with severe disability and an overall poor prognosis, with 30% to 40% mortality in the first 24 months after limb loss. As with coronary artery disease, the most common cause of symptomatic obstruction in the peripheral arterial tree is atherosclerosis, a systemic inflammatory process in which cholesterol-laden plaque builds up in the artery and eventually blocks the lumen. Typical risk factors include age, gender, diabetes, tobacco abuse, hypertension, and hyperlipidemia.

Wire-Interwoven Nitinol Stent Outcome in the Superficial Femoral and Proximal Popliteal Arteries Twelve-Month Results of the SUPERB Trial

Background—Stent-based therapy in the superficial femoral and popliteal arteries in patients with peripheral artery disease is compromised by restenosis and risk of stent fracture or distortion. A novel self-expanding nitinol stent was developed that incorporates an interwoven-wire design (Supera stent, IDEV Technologies, Inc, Webster, TX) to confer greater radial strength, flexibility, and fracture resistance. Methods and Results—This prospective, multicenter, investigational device exemption, single-arm trial enrolled 264 patients with symptomatic peripheral artery disease undergoing percutaneous treatment of de novo or restenotic lesions of the superficial femoral or proximal popliteal (femoropopliteal) artery. Freedom from death, target lesion revascularization, or any amputation of the index limb at 30 days (+7 days) postprocedure was achieved in 99.2% (258/260) of patients (P<0.001). Primary patency at 12 months (360±30 days) was achieved in 78.9% (180/228) of the population (P<0.001). Primary patency by Kaplan–Meier analysis at 12 months (360 days) was 86.3%. No stent fracture was observed by independent core laboratory analysis in the 243 stents (228 patients) evaluated at 12 months. Clinical assessment at 12 months demonstrated improvement by at least 1 Rutherford–Becker category in 88.7% of patients. Conclusions—The SUPERB Trial, an investigational device exemption study using an interwoven nitinol wire stent in the femoropopliteal artery, achieved the efficacy and safety performance goals predesignated by the Food and Drug Administration. On the basis of the high primary patency rate, absence of stent fracture, and significant improvements in functional and quality-of-life measures, the Supera stent provides safe and effective treatment of femoropopliteal lesions in symptomatic patients with peripheral artery disease. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00933270.

Atherectomy for Infrainguinal Peripheral Artery Disease

Compared to conventional percutaneous transluminal angioplasty (PTA) and stent implantation for arterial occlusive diseases, atherectomy offers the theoretical advantages of eliminating stretch injury on arterial walls and reducing the rate of restenosis. Historically, however, neither rotational nor directional atherectomy, whether used alone or with adjunctive PTA, has shown any significant long-term benefit over PTA alone in the coronary or peripheral arteries. However, the SilverHawk Plaque Excision System has produced positive results in single-center prospective registries of patients with femoropopliteal and infrainguinal lesions, with reduced adjunctive PTA, minimal adjunctive stenting, and competitive 6-month and 12-month patency rates. In the observational nonrandomized TALON (Treating Peripherals with SilverHawk: Outcomes Collection) registry, freedom from target lesion revascularization was 80% for 87 patients at 12 months. Questions remaining for further research with this device include more accurate determination of an event rate for distal embolization, the appropriate use of distal protection, the value of and appropriate circumstances for adjunctive angioplasty, and definitive patency and clinical outcomes. Other atherectomy devices are discussed.

In-hospital costs of self-expanding nitinol stent implantation versus balloon angioplasty in the femoropopliteal artery (the VascuCoil Trial).

PURPOSE Although several prospective studies have examined the safety and efficacy of stent placement for femoropopliteal arterial disease, the current cost of these procedures is unknown. To estimate and compare hospital costs associated with conventional balloon angioplasty (percutaneous transluminal angioplasty [PTA]) and stent placement for patients with symptomatic peripheral arterial disease, the authors performed a prospective economic evaluation in conjunction with the Intracoil Femoropopliteal Stent Trial (VascuCoil). MATERIALS AND METHODS Between May 1997 and December 1999, 266 patients with stenotic or occluded superficial femoral or popliteal arteries were prospectively randomized to treatment with the IntraCoil stent or PTA. Detailed resource use and cost data for each patients initial revascularization procedure and ensuing hospitalization were collected and analyzed on an intention-to-treat basis. RESULTS Compared with conventional balloon angioplasty, stent placement did not improve clinical outcomes but increased procedure duration, equipment costs, and physician services. As a result, initial hospital costs were approximately 3,500 dollars higher for patients randomized to the IntraCoil stent, compared with PTA (8,435 dollars vs 4,980 dollars; P < .001). CONCLUSIONS As performed in the VascuCoil trial, primary stent placement for femoropopliteal disease did not improve clinical outcomes but increased initial treatment costs by more than 3,000 dollars. Because there were no substantial differences in subsequent clinical outcomes between the two treatments, it is unlikely that these increased initial costs would be offset by savings in follow-up costs. These findings suggest that a strategy of routine stent implantation for patients undergoing femoropopliteal PTA is not optimal on economic grounds and that PTA with provisional stent implantation is preferred.

One-Year Outcomes Following Directional Atherectomy of Infrapopliteal Artery Lesions Subgroup Results of the Prospective, Multicenter DEFINITIVE LE Trial

Purpose: To report a subgroup analysis of the prospective, multicenter, single-arm DEFINITIVE LE trial to assess the effectiveness of directional atherectomy for the treatment of infrapopliteal artery lesions at 1 year. Methods: In the DEFINITIVE LE trial, follow-up assessments occurred up to 1 year postprocedure. Of the 800 patients enrolled, 145 subjects with 189 infrapopliteal lesions met the criteria for this analysis. Seventy (48.3%) and 75 (51.7%) patients were suffering critical limb ischemia (CLI) and intermittent claudication, respectively; 68.3% (99/145) had diabetes. The mean lesion length was 58±44 mm (all lesions); 20.2% were occluded. The primary endpoint for patients with claudication was duplex ultrasound–derived primary patency, while for subjects with CLI it was freedom from major amputation of the target limb at 1 year. Endpoints and adverse events were independently assessed. Results: Procedure success (≤30% residual stenosis) was achieved in 84% of treated lesions. The 1-year primary patency rate was 84% (claudicants 89.6% and CLI patients 78%, p=0.11), and the freedom from major amputation rate was 97.1% (claudicants 100% and CLI 93.8%, p=0.03). In both claudication and CLI patients, significant improvements in Rutherford category and objective measures of walking distance and quality of life were seen at 1 year in comparison to baseline. Conclusion: This study demonstrates that directional atherectomy in infrapopliteal arteries results in promising technical and clinical results at 1 year for claudicant as well as CLI patients.

SUPERB final 3-year outcomes using interwoven nitinol biomimetic supera stent

Long‐term outcomes of an interwoven nitinol stent design represent the best in class for treatment of lower limb arterial obstructive disease

Neutrophil lymphocyte ratio in peripheral vascular disease: a review

ABSTRACT Peripheral vascular disease (PVD) carries a significant morbidity and mortality. The role of inflammatory markers in cardiovascular medicine has been extensively studied. Neutrophil Lymphocyte ratio (NLR) is a novel biomarker which has been proposed as a marker of cardiovascular disease. We review the association of NLR with PVD. NLR has been shown to be an independent predictor of early and midterm amputation in patients with acute limb ischemia after embolectomy. A recent risk stratification model including NLR has emerged as a predictor of mortality and/or major amputation in critical limb ischemia. NLR appears to be an independent predictor of severity of PVD based on TransAtlantic Inter-Society Consensus classification, which classifies PVD based on the nature of the lesion and its anatomic distribution. A review of a large cohort of patients who had major vascular surgery, an NLR > 5 was found to be an independent predictor of mortality. In patients with intermediate carotid artery disease, NLR of 2.6 was found to be an independent variable for symptomatic carotid artery disease. It is a good predictor of early death in acute pulmonary embolism. NLR is inexpensive and readily available and appears to have a major role in peripheral vascular disease.