John R. Laird

Morphologic and angiographic features of coronary plaque rupture detected by intravascular ultrasound

OBJECTIVES This study was designed to report the clinical and angiographic correlates of plaque rupture detected by intravascular ultrasound (IVUS). BACKGROUND Acute coronary syndromes result from spontaneous plaque rupture and thrombosis. METHODS We report 300 plaque ruptures in 257 arteries in 254 patients. Plaque ruptures were detected during pre-intervention IVUS. Standard clinical, angiographic, and IVUS parameters were collected and/or measured. One lesion per patient was analyzed. RESULTS Multiple ruptures were observed in 39 of 254 patients (15%), 36 in the same artery. Plaque rupture occurred not only in patients with unstable angina (46%) or myocardial infarction (MI, 33%), but also stable angina (11%) or no symptoms (11%). The tear in the fibrous cap could be identified in 157 of 254 patients; 63% occurred at the shoulder of the plaque and 37% in the center of the plaque. Thrombi were more common in patients with unstable angina or MI (p = 0.02) and in multiple ruptures (p = 0.04). The plaque rupture site contained the minimum lumen area (MLA) site in only 28% of patients; rupture sites had larger arterial and lumen areas and more positive remodeling than MLA sites. Intravascular ultrasound plaque rupture strongly correlated with complex angiographic lesion morphology: ulceration in 81%, intimal flap in 40%, thrombus in 7%, and aneurysm in 7%. CONCLUSIONS Plaque ruptures occur with varying clinical presentations, strongly correlate with angiographic complex lesion morphology, may be multiple, and usually do not cause lumen compromise.

Nitinol Stent Implantation Versus Balloon Angioplasty for Lesions in the Superficial Femoral Artery and Proximal Popliteal Artery Twelve-Month Results From the RESILIENT Randomized Trial

Background—Controversy still exists regarding the best endovascular treatment strategy for patients with symptomatic disease of the superficial femoral artery. There are conflicting data regarding the benefits of superficial femoral artery stenting and the role of primary stenting compared with balloon angioplasty with provisional stent implantation. Methods and Results—A total of 206 patients from 24 centers in the United States and Europe with obstructive lesions of the superficial femoral artery and proximal popliteal artery and intermittent claudication were randomized to implantation of nitinol stents or percutaneous transluminal angioplasty. The mean total lesion length was 71 mm for the stent group and 64 mm for the angioplasty group. Acute lesion success (<30% residual stenosis) was superior for the stent group compared with the angioplasty group (95.8% versus 83.9%; P<0.01). Twenty-nine (40.3%) patients in the angioplasty group underwent bailout stenting because of a suboptimal angiographic result or flow-limiting dissection. Bailout stenting was treated as a target lesion revascularization and loss of primary patency in the final analysis. At 12 months, freedom from target lesion revascularization was 87.3% for the stent group compared with 45.1% for the angioplasty group (P<0.0001). Duplex ultrasound-derived primary patency at 12 months was better for the stent group (81.3% versus 36.7%; P<0.0001). Through 12 months, fractures occurred in 3.1% of stents implanted. No stent fractures resulted in loss of patency or target lesion revascularization. Conclusions—In this multicenter trial, primary implantation of a self-expanding nitinol stent for moderate-length lesions in the superficial femoral artery and proximal popliteal artery was associated with better acute angiographic results and improved patency compared with balloon angioplasty alone. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00673985.

Drug-coated balloon versus standard percutaneous transluminal angioplasty for the treatment of superficial femoral and popliteal peripheral artery disease: 12-month results from the IN.PACT SFA randomized trial.

Background— Drug-coated balloons (DCBs) have shown promise in improving the outcomes for patients with peripheral artery disease. We compared a paclitaxel-coated balloon with percutaneous transluminal angioplasty (PTA) for the treatment of symptomatic superficial femoral and popliteal artery disease. Methods and Results— The IN.PACT SFA Trial is a prospective, multicenter, single-blinded, randomized trial in which 331 patients with intermittent claudication or ischemic rest pain attributable to superficial femoral and popliteal peripheral artery disease were randomly assigned in a 2:1 ratio to treatment with DCB or PTA. The primary efficacy end point was primary patency, defined as freedom from restenosis or clinically driven target lesion revascularization at 12 months. Baseline characteristics were similar between the 2 groups. Mean lesion length and the percentage of total occlusions for the DCB and PTA arms were 8.94±4.89 and 8.81±5.12 cm (P=0.82) and 25.8% and 19.5% (P=0.22), respectively. DCB resulted in higher primary patency versus PTA (82.2% versus 52.4%; P<0.001). The rate of clinically driven target lesion revascularization was 2.4% in the DCB arm in comparison with 20.6% in the PTA arm (P<0.001). There was a low rate of vessel thrombosis in both arms (1.4% after DCB and 3.7% after PTA [P=0.10]). There were no device- or procedure-related deaths and no major amputations. Conclusions— In this prospective, multicenter, randomized trial, DCB was superior to PTA and had a favorable safety profile for the treatment of patients with symptomatic femoropopliteal peripheral artery disease. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique Identifiers: NCT01175850 and NCT01566461.

Nitinol Stent Implantation Versus Balloon Angioplasty for Lesions in the Superficial Femoral Artery and Proximal Popliteal ArteryClinical Perspective

Background—Controversy still exists regarding the best endovascular treatment strategy for patients with symptomatic disease of the superficial femoral artery. There are conflicting data regarding the benefits of superficial femoral artery stenting and the role of primary stenting compared with balloon angioplasty with provisional stent implantation. Methods and Results—A total of 206 patients from 24 centers in the United States and Europe with obstructive lesions of the superficial femoral artery and proximal popliteal artery and intermittent claudication were randomized to implantation of nitinol stents or percutaneous transluminal angioplasty. The mean total lesion length was 71 mm for the stent group and 64 mm for the angioplasty group. Acute lesion success (<30% residual stenosis) was superior for the stent group compared with the angioplasty group (95.8% versus 83.9%; P<0.01). Twenty-nine (40.3%) patients in the angioplasty group underwent bailout stenting because of a suboptimal angiographic result or flow-limiting dissection. Bailout stenting was treated as a target lesion revascularization and loss of primary patency in the final analysis. At 12 months, freedom from target lesion revascularization was 87.3% for the stent group compared with 45.1% for the angioplasty group (P<0.0001). Duplex ultrasound-derived primary patency at 12 months was better for the stent group (81.3% versus 36.7%; P<0.0001). Through 12 months, fractures occurred in 3.1% of stents implanted. No stent fractures resulted in loss of patency or target lesion revascularization. Conclusions—In this multicenter trial, primary implantation of a self-expanding nitinol stent for moderate-length lesions in the superficial femoral artery and proximal popliteal artery was associated with better acute angiographic results and improved patency compared with balloon angioplasty alone. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00673985.

Intravascular Ultrasound Analysis of Infarct-Related and Non–Infarct-Related Arteries in Patients Who Presented With an Acute Myocardial Infarction

Background Previous studies have reported diffuse destabilization of atherosclerotic plaques in acute myocardial infarction (AMI). Methods and Results We used intravascular ultrasound (IVUS) to assess 78 coronary arteries (38 infarct‐related arteries [IRAs] with culprit and nonculprit lesions and 40 non‐IRAs) from 38 consecutive AMI patients. IVUS analysis included qualitative and quantitative measurements of reference and lesion external elastic membrane (EEM), lumen, and plaque plus media (P&M) area. Positive remodeling was defined as lesion/mean reference EEM>1.0. Culprit lesions were identified by a combination of ECG, wall motion abnormalities (ventriculogram or echocardiogram), scintigraphic perfusion defects, and coronary angiogram. Culprit lesions contained more thrombus (23.7% versus 3.4% in nonculprit IRA plaques and 3.1% in non‐IRA plaques; P<0.0011). Culprit lesions were predominantly hypoechoic (63.2% versus 37.9% of nonculprit IRA plaques and 28.1% of non‐IRA plaques; P=0.0022). Culprit lesions were longer (17.5±10.1, 9.8±4.0, and 10.3±5.7 mm, respectively; P<0.0001), had larger EEM area (15.0±6.0, 11.5±5.7, and 12.6±5.6 mm2, respectively; P±0.0353) and P&M area (13.0±6.0, 7.5±3.7, 9.3±4.3 mm2, respectively; P<0.0001), smaller lumens (2.0±0.9,4.1±3.1, and 3.4±2.5mm2, respectively; P=0.0009), and more positive remodeling (79.4%, 59.0%, and 50.8%, respectively; P=0.0155). The frequency of plaque rupture/dissection was greater in culprit, nonculprit IRA, and non‐IRA plaques in AMI patients than in a control group of chronic stable angina patients with multivessel IVUS imaging. Conclusions Culprit plaques have more markers of instability (thrombus, positive remodeling, and large plaque mass); however, these markers of instability are not typically found elsewhere. This suggests that the vascular event in AMI patients is determined by local pre‐event lesion morphologies. (Circulation. 2003;107:2889‐2893.)

Limb Salvage following Laser-Assisted Angioplasty for Critical Limb Ischemia: Results of the LACI Multicenter Trial

Purpose: To evaluate the effectiveness of laser-assisted angioplasty for patients with critical limb ischemia (CLI) who were poor candidates for surgical revascularization. Methods: A prospective registry at 14 sites in the US and Germany enrolled 145 patients with 155 critically ischemic limbs; the patients were poor candidates for bypass surgery owing to inadequate target vessel or saphenous vein, prohibitive cardiac disease, or significant comorbidities (ASA class 4). Additional comorbid risk factors included diabetes in 66%, hypertension in 83%, previous stroke in 21%, and myocardial infarction in 23%. Endovascular treatment included guidewire traversal and excimer laser angioplasty followed by balloon angioplasty with optional stenting. Results: Occlusions were present in 92% of limbs. A mean of 2.7±1.4 lesions were treated per limb; the total median treatment length was 11 cm (mean 16.2, range 0.2–123). Stents were implanted in 45% of limbs. Procedural success, defined as <50% residual stenosis in all treated lesions, was seen in 86% of limbs. At 6-month follow-up, limb salvage was achieved in 110 (92%) of 119 surviving patients or 118 (93%) 127 limbs. Conclusion: Excimer laser-assisted angioplasty for CLI offers high technical success and limb salvage rates in patients unfit for traditional surgical revascularization.

Nitinol Stent Implantation vs. Balloon Angioplasty for Lesions in the Superficial Femoral and Proximal Popliteal Arteries of Patients With Claudication: Three-Year Follow-up From the RESILIENT Randomized Trial:

Purpose To evaluate longer outcomes of primary nitinol stenting for the treatment of femoropopliteal lesions up to 15 cm long after these stents were found to have superior short-term patency vs. balloon angioplasty. Methods Two hundred and six patients (143 men; mean age 67 years) with intermittent claudication due to superficial femoral and proximal popliteal artery lesions were randomized (2:1) to treatment with nitinol stents or balloon angioplasty at 24 US and European centers and followed for 3 years. In that time, 15 patients died, 20 withdrew consent, and 10 were lost to follow-up, leaving 161 (78.2%) patients for 36-month assessment. Results The 12-month freedom from target lesion revascularization (TLR) was 87.3% for the stent group vs. 45.2% for the angioplasty group (p<0.0001). At 3 years, there was no difference in survival (90.0% vs. 91.7%, p=0.71) or major adverse events (75.2% vs. 75.2%, p=0.98) between the stent and angioplasty groups. Duplex ultrasound was not mandated after the first year, so stent patency could not be ascertained beyond 1 year, but freedom from TLR at 3 years was significantly better in the stent group (75.5% vs. 41.8%, p<0.0001), as was clinical success (63.2% vs. 17.9%, p<0.0001). At 18 months, a 4.1% (12/291) stent fracture rate was documented. Conclusion In this multicenter trial, primary implantation of a nitinol stent for moderate-length lesions in the femoropopliteal segment of patients with claudication was associated with better long-term results vs. balloon angioplasty alone.

Use of a Constitutively Active Hypoxia-Inducible Factor-1α Transgene as a Therapeutic Strategy in No-Option Critical Limb Ischemia Patients Phase I Dose-Escalation Experience

Background— Critical limb ischemia, a manifestation of severe peripheral atherosclerosis and compromised lower-extremity blood flow, results in a high rate of limb loss. We hypothesized that adenoviral delivery of a constitutively active form of the transcription factor hypoxia-inducible factor-1&agr; (ie, Ad2/HIF-1&agr;/VP16 or HIF-1&agr;) into the lower extremity of patients with critical limb ischemia would be safe and might result in a durable clinical response. Methods and Results— This phase I dose-escalation program included 2 studies: a randomized, double-blind, placebo-controlled study and an open-label extension study. In total, 34 no-option patients with critical limb ischemia received HIF-1&agr; at doses of 1×108 to 2×1011 viral particles. No serious adverse events were attributable to study treatment. Five deaths occurred: 3 in HIF-1&agr; and 2 in placebo patients. In the first (randomized) study, 7 of 21 HIF-1&agr; patients met treatment failure criteria and had major amputations. Three of the 7 placebo patients rolled over to receive HIF-1&agr; in the extension study. No amputations occurred in the 2 highest-dose groups of Ad2/HIF-1&agr;/VP16 (1×1011 and 2×1011 viral particles). The most common adverse events included peripheral edema, disease progression, and peripheral ischemia. At 1 year, limb status observations in HIF-1&agr; patients included complete rest pain resolution in 14 of 32 patients and complete ulcer healing in 5 of 18 patients. Conclusions— HIF-1&agr; therapy in patients with critical limb ischemia was well tolerated, supporting further, larger, randomized efficacy trials.

Excimer laser-assisted recanalization of long, chronic superficial femoral artery occlusions.

PURPOSE To examine the safety and efficacy of excimer laser-assisted angioplasty (ELA) for recanalization of superficial femoral artery (SFA) occlusions. METHODS Data were analyzed from 318 consecutive patients (207 men; mean age 64.2 +/- 10.7 years, range 33-91) who underwent ELA of 411 SFAs with chronic occlusions averaging 19.4 +/- 6.0 cm in length. More than 75% of patients had severe claudication (category 3). Critical lower limb ischemia with rest pain or minor tissue loss was present in 6 and 15 patients, respectively. The mean ankle brachial index (ABI) before and after exercise was 0.62 +/- 0.15 and 0.40 +/- 0.18, respectively. RESULTS The initial attempt (crossover approach 89.7%, antegrade 6.6%, transpopliteal 3.6%) to cross the occlusion with an excimer laser catheter was successful in 342 (83.2%) of 411 limbs. A secondary attempt performed in 44 of 69 failed cases was successful in 30 limbs, increasing the technical success rate to 90.5% (372/411). Complications included acute reocclusion (4, 1.0%), perforation (9, 2.2%), and distal thrombosis/embolization (16, 3.9%). Postprocedurally, 219 (68.8%) patients were asymptomatic; mild (category 1) or moderate (category 2) claudication remained in 53 (16.6%) and 26 (8.2%) patients, respectively. The primary patency at 1 year was 33.6%. In the majority of patients, reocclusion was treatable on an outpatient basis. The 1-year assisted primary and secondary patency rates were 65.1% and 75.9%, respectively. CONCLUSIONS Long SFA occlusions can be recanalized safely and successfully by ELA. However, to maintain patency and quality of life, intensive surveillance using objective testing followed by prompt repeat intervention are mandatory.

Overview of New Technologies for Lower Extremity Revascularization

Lower extremity peripheral arterial occlusive disease poses a unique challenge to traditional angioplasty-based endovascular therapies. The diffuse nature of lower extremity atherosclerotic disease, the presence of chronic total occlusions, poor distal runoff, and the presence of critical limb ischemia all have contributed to the disappointing results of balloon angioplasty for complex infrainguinal arterial disease. These challenges have spawned the development of a host of new technologies in an attempt to improve the safety and effectiveness of percutaneous revascularization for lower extremity peripheral arterial occlusive disease. This review summarizes the recent advances in available technologies, including novel angioplasty balloons; nitinol stents, stent grafts, and drug-eluting stents; excisional, laser, and rotational atherectomy devices; devices for crossing total occlusions; true-lumen reentry devices; thrombectomy catheters; and embolic protection devices.