Monitoring antiplatelet therapy during peripheral vascular and coronary interventions

Platelets play a central role in the initiation and propagation of thrombus formation. The use of antiplatelet and antithrombotic medications during peripheral vascular and coronary interventions helps reduce the likelihood of intravascular thrombus formation and adverse ischemic events. As formation of intravascular thrombus and subacute stent thrombosis are thrombin- and platelet-mediated phenomenon, achieving optimal activated clotting time and platelet inhibition (PI) during the interventional procedure is critical. However, as a quick and easy measure of platelet function has previously not been available in the interventional laboratory, cardiovascular interventions are routinely performed after administration of oral or intravenous antiplatelet agents without evaluating platelet function. Recently, point-of-care rapid platelet function assays have become available that allow quick and reproducible measure of platelet function in the interventional laboratory after administration of aspirin, thienopyridines, and glycoprotein IIb/IIIa inhibitors. Though PI can now be routinely measured during vascular interventions, considerable inconsistencies exist in the management of patients based on these results. We present an algorithm for the management of antiplatelet therapy during cardiovascular interventions based on rapid evaluation of platelet function in the interventional laboratory.     

Percutaneous intravascular US as adjunct to catheter-based interventions: preliminary experience in patients with peripheral vascular disease

Catheter-based ultrasound (US) transducers may be introduced into the vascular system to record high-resolution images of the vessel wall and lumen. The potential advantages and existing liabilities of percutaneous intravascular US as an adjunct to transluminal vascular recanalization were investigated. A 6.6-F braided, polyethylene catheter enclosing a rotary drive shaft with a single-element, 20-MHz transducer at the distal tip was used in 17 patients undergoing percutaneous transluminal (balloon) angioplasty (PTA) alone (10 patients), PTA with implantation of an endovascular stent (two patients), atherectomy alone (two patients), or laser angioplasty with PTA and/or atherectomy (three patients). The arteries treated and examined included the common iliac in five patients, the external iliac in two, the superficial femoral in nine, and a vein graft-arterial anastomosis in one. In 14 cases PTA was employed as sole or adjunctive therapy; plaque cracks were clearly delineated with intravascular US in all 14 (100%) and dissections were observed in 11 (78%). Plaque-arterial wall disruption was less prominent in the arteries treated with mechanical atherectomy. The results of laser angioplasty reflected the adjunctive modality employed. After stent implantation, serial intravascular US documented effacement of PTA-induced plaque cracks and/or dissections. Intravascular US also aided in the quantitative assessment of luminal cross-sectional areas after the procedures (19.0-51.8 mm2). The observations recorded in this preliminary group of 17 patients illustrate the potential utility of intravascular US as an adjunct to conventional angiography in patients undergoing percutaneous revascularization.     

Adjunctive abciximab improves patency and functional outcome in endovascular treatment of femoropopliteal occlusions: initial experience

PURPOSE: To prospectively evaluate the safety and effectiveness of adjunctive administration of abciximab observed within 30 days and at 6 months after randomization in patients undergoing endovascular revascularization of long-segment femoropopliteal occlusions. MATERIALS AND METHODS: The study was approved by the local ethical committee, and patients gave written informed consent. In a prospective, double-blind, placebo-controlled design, patients undergoing percutaneous treatment for long-segment (>5 cm) femoropopliteal occlusions were randomly assigned to receive abciximab or a placebo; all patients also received standard-dose heparin. Effectiveness and safety analyses were based on an intention-to-treat approach. Patency was calculated according to life-table analysis, and P values were derived from the log-rank statistic. The P values for dichotomous safety end points were calculated with the Fisher exact test. Odds ratios were calculated for subgroup analyses. Logistic regression modeling was used for analysis of the safety bleeding data. RESULTS: A total of 98 patients (103 limbs) were included: 47 patients received abciximab and 51 received a placebo. Patency with abciximab versus placebo was 95.7% versus 80.4% (relative risk, 0.21; 95% confidence interval: 0.05, 0.96; P = .02) at 30 days and was 61.7% versus 41.2% (relative risk, 0.57; 95% confidence interval: 0.32, 1.01; P = .03), coupled with a better clinical outcome according to the Rutherford score, at the end of follow-up (P = .03). Risk of major bleeding was not significantly increased, while access-site bleeding was significantly higher among patients receiving abciximab (odds ratio, 2.9; 95% confidence interval: 1.04, 8.2; P = .04). CONCLUSION: The data show that adjunctive administration of abciximab has a favorable effect on patency and clinical outcome in patients undergoing complex femoropopliteal catheter interventions not hampered by serious bleeding. Treatment effect of abciximab observed at 30 days was maintained at 6-month follow-up.     

Laser-assisted percutaneous angioplasty: initial clinical experience in peripheral arteries

Experimental and animal studies have shown that laser energy can vaporize intra-vascular thrombus and atheroma, suggesting that it may have a role in percutaneous angioplasty. Argon laser energy transmitted via a flexible fibre introduced through a percutaneous catheter was used in 15 patients undergoing balloon angioplasty of femoral or popliteal arteries. Of four stenoses, laser alone produced improvement of the lumen in two. Of 11 occlusions some degree of clearance of the lumen was achieved by laser in eight prior to balloon dilatation. Extravasation of contrast medium indicating wall perforation occurred in two patients, without clinical sequelae. No other complications, such as embolism, arterial spasm or toxic effects were observed. There was one acute re-occlusion, almost certainly not related to the use of laser. There have been no late complications. The ability of laser to influence favourably vascular occlusion is confirmed, but technical advances are necessary to avoid vessel wall perforation consistently and to improve the production of an adequate lumen before its potential can be fully realized.     

Use of aortic cuffs to exclude iliac artery aneurysms during AneuRx stent-graft placement: initial experience.

PURPOSE: As many as 39% of patients who undergo aortic endografting for abdominal aortic aneurysm disease will have ectasia of the iliac arteries that will require intervention. Coil embolization of the internal iliac artery and extension of the graft to the external iliac artery is one solution to this problem. However, 19%-41% of these patients experience buttock claudication, which may be permanent, after unilateral embolization. The authors examined an alternative: the use of larger-sized aortic cuffs to seal the iliac limb. Outcomes and short-term results are presented in this article. MATERIALS AND METHODS: From October 1999 to August 2000, 144 AneuRx stent-grafts were placed at the authors' institution. Among the population receiving stent-grafts, 14 patients had 15 aortic cuffs placed across the distal iliac graft limbs to seal them and preserve flow to the internal iliac artery. One patient had bilateral cuffs placed. Five patients had embolization of the contralateral internal iliac artery because of bilateral disease. Patients were followed with computed tomography (CT) at 1, 6, and 12 months to evaluate for endoleaks. RESULTS: One- and 6-month endoleak rates, determined from only those patients with follow-up CT, were 0% and 10%, respectively. One type II endoleak was first discovered 9 months after graft placement. It sealed spontaneously at 15-month follow-up. One patient among the five who had internal iliac artery embolization had claudication. Mean CT follow-up was 7.8 months (range, 1-15). One patient declined CT but was alive and well 11 months after endografting. One patient moved across the country and declined follow-up. CONCLUSION: Placement of aortic cuffs in dilated iliac arteries can preserve flow to the ipsilateral internal iliac artery and provide an adequate seal. Additionally, the option of later treatment is maintained. Patients with bilateral iliac ectasia can undergo stent-graft placement without bilateral internal iliac artery embolization. Longer-term follow-up in larger numbers of patients will be important to determine the ultimate durability of this technique.     

Percutaneous transluminal angioplasty of peripheral vascular disease: A two-year experience

Over a 23-month period, 172 successful peripheral angioplasties were performed. Life-table analysis gave a two-year patency rate for the total series of 80%. The patency rate for aorto-iliac and femoral-popliteal lesions was 86% and 70%, respectively. Only one late failure occurred in the group of 44 arteries follwed for longer than eight months.     

Use of a novel percutaneous biopsy localization device: initial musculoskeletal experience

OBJECTIVE: To preliminarily evaluate a new CT-biopsy guidance device, the SeeStar (Radi, Uppsala, Sweden), for use in musculoskeletal applications. DESIGN: The device was evaluated using an imaging phantom and in various simulated clinical biopsy situations. The phantom study was undertaken to optimize the linear metallic artifacts produced by the guidance device. The phantom and guidance device were imaged with CT after altering different imaging parameters, including field of view, filter, focal spot size, kV, mAs, slice thickness and pitch. Clinical biopsy situations were simulated for a superficial biopsy, a deep biopsy and a horizontal biopsy approach. RESULTS: Altering CT parameters had little effect on the subjective appearance of the linear metal artifact, which is used to plan the biopsy approach. Placement of an 18-G needle inside of the biopsy device was subjectively helpful in exaggerating the artifact. Use of this artifact could be helpful in planning biopsy approach for deep lesions or lesions near critical structures. The metal guide on the device adequately supports a standard biopsy needle, making it potentially advantageous for biopsy of superficial lesions and lesions approached from a horizontal orientation. CONCLUSION: Use of this CT-biopsy guidance device is potentially useful for musculoskeletal applications. The linear metal artifact produced by the device can help plan the biopsy approach. The device can also be useful in biopsy situations where the biopsy needle requires external support during imaging.     

多层螺旋CT周围血管成像的初步应用

目的 :探讨多层螺旋CT(MSCT)在周围血管疾病中的应用价值。方法 :对 18例临床怀疑周围血管疾病的患者 ,均行上肢或下肢动脉或静脉CT血管造影。动脉系统疾病经肘前静脉以 3ml/s流率注入 10 0ml对比剂 ,延迟 2 5～40s后扫描 ;静脉性疾病经足背静脉或手背静脉以 1ml/s流率注入 5 0ml对比剂 ,延迟时间为 60～ 70s。扫描条件为层厚3 .2mm ,重建间隔 1.6mm ,螺距 1.2 5。结果 :动脉系统疾病 10例 ,狭窄或闭塞性疾病 9例 ,其中 1例合并动脉瘤 ,1例传统血管造影均不能插管操作 ,1例动脉瘤MRA以及传统血管造影均没有做出正确诊断 ;1例为正常下肢动脉。静脉系统疾病 3例 ,其中下肢深静脉血栓 2例 ,上肢多发性静脉瘤 1例 ,经传统血管造影证实。结论 :应用MSCT诊断周围血管疾病有一定的临床价值。     

The clinical application of cryoplasty for infrainguinal peripheral arterial disease

Interventional outcomes for peripheral arterial disease of the lower extremity have long suffered from suboptimal patency rates. Many drugs and devices have been studied in an attempt to alter the aggressive neointimal response witnessed in infra-inguinal vessels with little success. Cryoplasty, a recent entrant into the endovascular arena, combines the time-tested mechanics of percutaneous transluminal angioplasty with the biologically favorable effects of cryotherapy. Cryoplasty specifically targets infra-inguinal lesions and minimizes neointimal proliferation via induction of apoptosis in the cell lines that contribute to restenosis. In addition, the mechanistic effects on the architecture of the vessel wall and the plaque itself have been found to reduce the likelihood of significant dissection following cryoplasty as compared with those expected with percutaneous transluminal angioplasty. Several clinical trials have demonstrated the efficacy of cryoplasty in patients with superficial femoral and popliteal arterial disease, as well as in critical limb ischemia patients with tibioperoneal arterial disease. Current clinical applications in the lower extremity will be reviewed along with technical tips for device use and opportunities for device synergy with other existing technologies.     

Initial experience with the combination of reteplase and abciximab for thrombolytic therapy in peripheral arterial occlusive disease: a pilot study.

PURPOSE: To report the efficacy of catheter-directed thrombolysis with a combination of a thrombolytic agent (reteplase) and a glycoprotein (GP) IIb/IIIa platelet receptor antagonist (abciximab) in peripheral arterial occlusive disease. MATERIALS AND METHODS: Fifteen patients with lower extremity arterial thromboses (age range, 40-96 y; mean, 73 y) were prospectively enrolled in a protocol approved by the Institutional Review Committee. Nine patients had native arterial occlusions, three (33%) of whom had subacute symptoms (>14 d) and one of whom had chronic symptoms (>3 mo). Four patients had acute arterial graft thromboses. Two patients with lower extremity bypass grafts presented with subacute limb ischemia. All patients received catheter-directed infusion of reteplase (0.5 U/h) in combination with intravenous administration of abciximab (0.25-mg/kg bolus followed by 0.125 microg/kg/min infusion) for 12 hours without systemic heparinization. The thrombolytic success was studied by Doppler ultrasonography (US) and angiography. RESULTS: Complete thrombolysis and clinical success was achieved in 14 of the 15 patients (93%). One patient with unsuccessful thrombolysis underwent major amputation. The mean thrombolysis time per Doppler US procedure was 6.8 hours (range, 2-30 h). Angiographic patency was achieved at a mean of 17.5 hours (range, 4-36 h) corresponding to a mean dose of reteplase of 8.8 U. The mean increase in ankle-brachial index was 0.52 (range, 0-0.9). No major hemorrhagic complications occurred. The 30-day primary patency rate was 93%. CONCLUSION: The combination of reteplase and abciximab in catheter-directed arterial thrombolysis is feasible and effective. This combination therapy pilot study suggests short thrombolysis times and minimal adverse effects in catheter-directed thrombolytic therapy for peripheral arterial occlusive disease.     

Catheter-directed thrombolytic therapy in peripheral artery occlusions: combining reteplase and abciximab

OBJECTIVE: The goal of this study was to assess the safety and efficacy of combination therapy consisting of the third-generation plasminogen activator reteplase and the glycoproteins IIb and IIIa platelet receptor antagonist abciximab for thrombolysis in peripheral artery occlusive disease. This two-center experience focused on immediate thrombolytic success, thrombolysis time, complication rate, and 30-day patency rate. SUBJECTS AND METHODS: Fifty patients with arterial occlusive disease (age range, 40-96 years; mean age, 69 years) were prospectively enrolled at two centers. Eighteen patients (36%) had native artery thromboses, and 32 patients (64%) had graft thromboses. Catheter-directed intraarterial thrombolytic infusion of reteplase (average dose, 0.51 U/hr; range, 0.25-1 U/hr) was combined with IV infusion of abciximab (bolus, 0.25 mg/kg of body weight; 12-hr infusion, 0.125 microg/kg of body weight per minute). Nontherapeutic heparin (100-400 U/hr) was given intraarterially during the thrombolytic infusion. RESULTS: Complete thrombolysis was achieved in 89% of the patients with native artery occlusions and 94% of the patients with graft occlusions for an overall rate of 92%. The average thrombolysis time was 20.7 hr (range, 4-41 hr) with a mean reteplase dose of 12.1 U (range, 2-23 U). Major hematoma occurred in 12% of the patients, with an average blood transfusion of 3.1 U of packed RBC (range, 1-11 U), and correlated to increased thrombolysis time and dose. No intracranial hemorrhage occurred. The 30-day primary patency rate was 92%. Two patients (4%) underwent amputation, including one major amputation (2%), within 30 days of thrombolysis. CONCLUSION: The combination of reteplase and abciximab in catheter-directed arterial thrombolysis is feasible and effective. Results of this combination therapy suggest acceptable thrombolysis times and doses with tolerable complication rates. Which patient group might benefit the most from combination therapy and the long-term results of combination therapy still need to be determined.     

Lowering iodinated contrast concentration in infrainguinal endovascular interventions: a three-armed randomized controlled non-inferiority trial

Objectives

To determine the influence of lowering iodinated contrast concentration on confidence of interventional radiologists in diagnosing and treating lesions during endovascular interventions in patients with symptomatic peripheral arterial disease (PAD).

Methods

A randomized controlled non-inferiority trial was performed in 60 patients. Intervention was performed with contrast concentrations (in mg of iodine per mL, mgI/mL) of 300 (standard), 240, or 140 mgI/mL. Primary outcome was confidence (score 0-100 %) of radiologists in diagnosing and treating arterial lesions. Secondary outcomes were procedural iodine load and image quality (i.e. non-diagnostic, limited, diagnostic, exemplary).

Results

Median confidence scores in diagnosing lesions were 100 % (range 81-100 %) for the 300 group (n?=?21), 100 % (range 82-100 %) for the 240 group (n?=?19), and 100 % (range 91-100 %) for the 140 group (n?=?20) (both p?=?1.00 compared to the 300 group). Median scores for treating lesions in the 240 and 140 groups, 100 % (range 79-100 %, p?=?0.40), and 100 % (range 63-100 %, p?=?0.25), respectively, were not lower compared to the 300 group (median 100 %, range 78-100 %). Procedural iodine load was lower in the 240 (24.3?±?7.6 g, p?=?0.022) and 140 groups (17.8?±?5.6 g, p?<?0.001) compared to the 300 group (29.7?±?6.3 g). Image quality was diagnostic for all groups.

Conclusion

Using iodine contrast of 140 mgI/mL for diagnosis and interventions in PAD patients significantly reduces administered iodine load without compromising image quality. Future use of lower iodine dose is recommended.

Key Points

? Lower iodinated contrast concentration during endovascular intervention does not decrease radiologist’s confidence. ? Image quality of standardized angiographies remains diagnostic using 140 mgI/mL iodinated contrast concentration. ? Iodine load during intervention can be decreased by >40 % when using 140 mgI/mL. ? Implementing the use of a lower iodinated contrast concentration will reduce the costs of the procedure.

     

Carbon-dioxide-guided vascular interventions: technique and pitfalls

Purpose: To evaluate the usefulness of carbon dioxide (CO2) angiography to guide vascular interventions. Methods: A prospective study was carried out of 50 procedures (angioplasty, stenting, stent-grafting and embolization) using CO2 angiography. Indications for using CO2 were renal impairment, cardiac failure, previous reaction to conventional iodinated contrast, or likelihood of needing high doses of conventional contrast. CO2 was intended to be the sole contrast agent. The use of additional conventional contrast or gadolinium was recorded, as were procedural complications. Radiation dose was compared with similar procedures using conventional contrast. Results: Angiographic quality was satisfactory in 44 (88%) procedures and CO2 guidance was all that was required; in 6 (12%) cases adjunctive use of conventional contrast or gadolinium was necessary. Contrast doses were significantly reduced and there was a trend toward decreased radiation doses with CO2. There were two significant complications but only one related to the use of CO2. Conclusion: CO2 angiography is well tolerated and can be successfully used to guide even complex vascular interventions. High-risk patients can be spared the risks of conventional contrast agents.     

1620例次外周血管介入治疗围手术期严重并发症的分析

目的 分析在外周血管介入诊治中出现的严重并发症类型、发生原因、处置及结局,以提高认识和处理严重并发症的能力.方法 回顾性分析近5年来在1 620例次外周血管介入诊治中所出现的严重并发症,每种并发症的发生率,发生后给予的处置,以及最后结局.结果 在1 620例次介入诊治中,在术中及术后1周内出现严重并发症共76例次,发生率为4.69%.出现的严重并发症达12种.大部分经处理后恢复正常,未遗留后遗症.部分患者遗留永久性合并症,如截瘫、下肢瘫痪、臀部肌肉坏死等.6例患者死亡.在死亡的6例患者中,4例同时发生肝功能衰竭及粒细胞缺乏症,1例死于腹膜后血肿及腹腔积血,1例死于肺栓塞.结论 ①多数外周血管介入治疗均可能出现严重并发症,这些并发症的发生大部分与术者对疾病的认识水平低和操作失当相关.②具备良好的基础知识、基本理论和基本技能,慎重选择介入治疗的适应证,细心操作,是减少介入治疗中严重并发症发生的关键.