Intracoronary urokinase as an adjunct to percutaneous transluminal coronary angioplasty in patients with complex coronary narrowings or angioplasty-induced complications

Adjunctive Catheter-Directed Thrombolysis during Primary PCI for ST-Segment Elevation Myocardial Infarction with High Thrombus Burden

BACKGROUND

High coronary thrombus burden has been associated with unfavorable outcomes in patients with ST-segment elevation myocardial infarction (STEMI), the optimal management of which has not yet been established.

METHODS

We assessed the adjunctive catheter-directed thrombolysis (CDT) during primary percutaneous coronary intervention (PCI) in patients with STEMI and high thrombus burden. CDT was defined as intracoronary infusion of tissue plasminogen activator (t-PA; monteplase).

RESULTS

Among the 1849 consecutive patients with STEMI, 263 had high thrombus burden. Moreover, 41 patients received t-PA (CDT group), whereas 222 did not receive it (non-CDT group). No significant differences in bleeding complications and in-hospital and long-term mortalities were observed (9.8% vs. 7.2%, p = 0.53; 7.3% vs. 2.3%, p = 0.11; and 12.6% vs. 17.5%, p = 0.84, CDT vs. non-CDT). In patients who underwent antecedent aspiration thrombectomy during PCI (75.6% CDT group and 87.4% non-CDT group), thrombolysis in myocardial infarction grade 2 or 3 flow rate after thrombectomy was significantly lower in the CDT group than in the non-CDT group (32.2% vs. 61.0%, p < 0.01). However, the final rates improved without significant difference (90.3% vs. 97.4%, p = 0.14).

CONCLUSIONS

Adjunctive CDT appears to be tolerated and feasible for high thrombus burden. Particularly, it may be an option in cases with failed aspiration thrombectomy.

Local Intracoronary Fibrinolysis in Acute Myocardial Infarction of Ectatic Coronary Arteries in the Post-Abciximab Era

Percutaneous intervention in the context of coronary artery ectasia (CAE) is penalized with no-reflow phenomenon. The glycoprotein-IIb/IIIa-inhibitor abciximab was the most accepted method for pharmacology thrombus resolution in this scenario, nevertheless, this agent was recently withdrawn. We describe 5 patients treated with local intracoronary fibrinolysis administrated through predesigned catheters in the setting of AMI and CAE.

Role of Intracoronary Fibrinolytic Therapy in Contemporary PCI Practice

Plaque rupture or plaque erosion leads to intracoronary thrombus formation resulting in coronary artery occlusion and ST-segment elevation myocardial infarction. Early restoration of blood flow in occluded coronary artery is the mainstay of therapy and it can be achieved by either thrombolytic therapy or primary percutaneous coronary intervention (P-PCI) or a combination of these two in many different ways. It has been proved that primary PCI is better than thrombolytic therapy in establishing early and effective recanalization of infarct related artery, reducing major adverse cardiovascular events (MACE) and increasing survival. There have been tremendous advances in PCI techniques over the years with newer stents, thrombectomy devices, and adjunctive pharmacotherapy. However, intracoronary thrombus continues to be the bane of interventional cardiologists. Failure of recanalization, suboptimal results, distal embolization, no reflow and impaired myocardial perfusion are some of the unresolved difficulties, regularly seen during PCI of patients with large intracoronary thrombus burden indicating an unmet need. This review focuses on emerging evidence about the usefulness of intracoronary thrombolytic therapy as an adjunct to PCI in patients with large intracoronary thrombus burden.

A case of successful reperfusion through a combination of intracoronary thrombolysis and aspiration thrombectomy in ST-segment elevation myocardial infarction associated with an ectatic coronary artery

Background

Large thrombus burdens in ectatic coronary arteries that remain after aspiration thrombectomy can negatively impact outcomes following percutaneous coronary interventions in patients with acute myocardial infarction.

Case presentation

A 53-year-old man presented with ST-segment elevation myocardial infarction (STEMI). Coronary angiography revealed an ectatic right coronary artery (RCA) that was completely occluded in the mid portion by a large amount of thrombus. Catheter-directed intracoronary thrombolysis with alteplase led to recovery of coronary blood flow, which multiple attempts of aspiration thrombectomy had failed to achieve. Coronary angiography 9 days later showed good blood flow and insignificant stenosis remaining in the RCA; this had completely resolved in 6 months’ follow-up coronary angiography.

Conclusion

Catheter-directed intracoronary thrombolysis can be performed effectively and safely when repeat aspiration thrombectomy fails to produce satisfactory coronary reperfusion in STEMI patients with large thrombus burdens in ectatic coronary arteries.

Coronary Angioplasty in Patients with Unstable Angina, with Special Reference to Preceding Treatment with Antithrombin III and Heparin

Seventy-nine patients undergoing percutane ous transluminal coronary angioplasty (PTCA) for unsta ble angina were analyzed with respect to preceding an tithrombin treatment; group I comprised patients (n = 26) without antecedent antithrombin therapy; group II, pa tients (n = 30) with heparin infusion for ≥24 h, and group III patients (n = 23) with ongoing heparin infusion and given antithrombin III concentrate immediately before the procedure because of plasma antithrombin III <85%. Immediate results were 89% (70 of 79) angiographic suc cess, five (6%) subacute occlusions (two subsequent non-Q wave infarctions), no emergency coronary artery bypass grafting (CABG), and no immediate mortality. There were no differences between the groups. From dis charge to 4 months, one patient died, one had a nonfatal infarction, and 24 (30%) had repeated PTCA or CABG. The cumulative 4-month event rate was 11 of 26 (42%) in group I, 10 of 30 (33%) in group II, and 7 of 23 (30%) in group III (NS). During PTCA, heparin bolus administra tion was guided by activated clotting time (ACT), aiming at>300 s. Baseline ACT was significantly less in patients not treated with heparin (129 ± 34 s in group I vs. 179 ± 38 and 162 ± 29 s in groups II and III, respectively; p < 0.05), but during the procedure, patients from all groups required the same amount of heparin (13,900 ± 4,800, 13,000 ± 6,800, and 13,000 ± 5,700 IU, respectively; NS) to reach similar maximum ACT levels (334 ± 36, 312 ± 32, and 319 ± 44 s, respectively; NS). Patients receiving warfarin ( n = 8) responded with a higher ACT (456 ± 110 s; p < 0.05) on lower doses of heparin (10,000 ± 3,800 IU). In conclusion, patients with unstable angina receiv ing individualized antithrombotic therapy can be success fully treated with PTCA, with an acute complication rate and long-term results comparable with those expected in patients undergoing elective procedures. The value of an tithrombin III substitution must be evaluated in random ized trials. Preprocedural heparin infusion does not re duce the need of extra heparin during the procedure. Key Words: Antithrombin III—Heparin—PTCA (percutane ous transluminal coronary angioplasty)—Unstable angina pectoris.

Adjunctive Pharmacotherapy for Thrombotic Coronary Lesions

Patients with unstable coronary syndromes are often found to have intracoronary thrombus on angiography. Despite advancements in catheter-based treatments for coronary disease, these lesions remain challenging, as percutaneous coronary intervention of thrombus-containing lesions may be associated with worse outcomes. This article reviews the literature on adjunctive pharmacotherapy in the treatment of thrombotic coronary lesions with special focus on ST-segment elevation myocardial infarction, lesions with high thrombus burden, and saphenous vein graft intervention.

Mechanical protection of cardiac microcirculation during percutaneous coronary intervention of saphenous vein grafts

Saphenous vein bypass grafts permeability is one of the most important limitations of open heart surgery. The risks associated with surgical re-intervention are greater than those associated with the initial procedure. While native coronary arteries usually have fixed, fibrotic or calcified atherosclerotic plaques, the disease in the vein grafts contains soft material. When this material is compressed during percutaneous angioplasty, there is an unfavorable immediate outcome due to distal embolization of thrombus and plaque debris. In addition, the risk of post-procedure adverse events are higher when the grafts have a long time of implantation, due to a greater risk of branch occlusion or no-reflow at the adjacent microcirculation. The clinical consequence is a Non-Q-Wave Myocardial Infarction that is reflected in the increased serum cardiac enzymes. It is because of this complication that the distal protection devices were developed. The purpose of this paper is to review and discuss the current data on the distal protection devices available now for the treatment of degenerative saphenous vein graft disease. Currently, there are two distal protection devices approved in the United States: the Guardwire Balloon and Aspiration (Export) System and the Filter Wire EX. Other devices like the Triactiv System, Angioguard XP/ECW, DOW, MedNova Cardioshield, Medtronic-AVE DPD and the E-Trap Filter are still being studied. The first observational studies showed the safety and efficacy of the approved devices. A large randomized trial initially confirmed a significant decrease of in-hospital and 30-day cardiac adverse events, mainly Non-Q-Wave Myocardial Infarction, when angioplasty was performed with the assistance of the Guardwire System. Subsequently, another randomized study showed an equivalence between the Guardwire System and the Filter Wire EX. Distal protection devices have an acceptable performance, however, further technological improvements are warranted for a quick preparation, delivery and/or retrieval of these devices.

Combined revascularization strategy for acute myocardial infarction in patients with intracoronary thrombus: preceding intracoronary thrombolysis and subsequent mechanical angioplasty

Thrombus in the infarct-related artery is one of the limitations for flow restoration in primary percutaneous transluminal coronary angioplasty (PTCA) treatment for acute myocardial infarction (AMI). The present study investigated the benefit of preceding intracoronary thrombolysis (ICT) by retrospectively analyzing acute phase flow restoration in 80 AMI patients with intracoronary thrombus: 40 undergoing primary PTCA alone (primary PTCA group) and 40 treated with preceding ICT plus PTCA (combined group). Acute phase Thrombolysis in Myocardial Infarction (TIMI) grade flow was as follows: TIMI 0/1: 35.0% vs 12.5% for the primary PTCA group and the combined group, p=0.06; TIMI 2: 7.5% vs 15.0%, p=NS; TIMI 3: 57.5% vs 72.5%, p=NS). In the subgroup analysis, it was also less in the combined group among 33 patients with a left anterior descending coronary artery (LAD) lesion (42.1 % vs 7.1%, p=0.08), but not among the remaining 47 with either a right coronary artery or left circumflex artery lesion. The combined therapy may potentially provide better acute phase flow restoration in AMI patients with an intracoronary thrombus in a LAD lesion.

Pharmacologic prevention of acute ischemic complications of coronary angioplasty

The risk of acute coronary occlusion following percutaneous transluminal coronary angioplasty (PTCA) has remained high despite the traditional use of heparin and aspirin. Interest has focused on newer strategies for preventing intracoronary thrombus formation, which is an important mechanism of abrupt vessel closure. Pretreatment with thrombolytic agents has failed vigorous testing in double-blind trials. Retrospective and observational studies have indicated that pretreatment with intravenous heparin is of benefit in patients with unstable symptoms, but prolonged infusion after angioplasty increases bleeding complications without improving outcomes. Subcutaneous heparin may be safer, but has not proved more effective. Oral dipyridamole has shown no advantage over aspirin, although there is evidence to suggest a benefit when given intravenously. Direct thrombin inhibitors (such as hirudin and hirulog) are associated with fewer early complications compared with heparin, but have yielded no apparent long-term benefit. The use of the antiplatelet drug ticlopidine is increasing, although long-term data are lacking. A great deal of recent interest has focused on newer antiplatelet agents, particularly the glycoprotein IIB/IIIa receptor inhibitor c7E3 Fab. In a large-scale trial, c7E3 significantly reduced the 30-day rate of mortality and cardiac events, and these benefits were maintained at 6 mo. This drug, unlike other antiplatelet agents, inhibits the final common pathway of platelet aggregation, which influences not only acute closure but has lasting effects for at least 6 mo. This may reflect a reduction in restenosis, although this remains to be proven. This article gives a brief overview of the pharmacologic agents available for the prophylaxis and treatment of acute ischemic complications of PTCA.

Catheter-based local thrombolysis with urokinase: comparative efficacy of intraluminal clot lysis with conventional urokinase infusion techniques in an in vivo porcine thrombus model

Local delivery of urokinase directly to the site of intraluminal clot using catheter-based technology has recently been introduced as a new technique to treat intracoronary thrombus and thrombus-containing stenoses. The purpose of this study was to compare the efficacy of urokinase therapy administered by local drug-delivery catheters with conventional urokinase-infusion techniques in dissolving intraluminal clot and intramurally depositing drug at the site of arterial injury in an in vivo porcine model. Five techniques of urokinase administration were studied in 65 pigs, including intravenous systemic bolus (1,000,000 units), guiding catheter infusion (500,000 units), local intraluminal infusion with a Roubin catheter (150,000 units), local infusion by the Dispatch catheter (150,000 units), and local delivery by the hydrogel-coated balloon (700 units). All five techniques were initially compared with respect to the quantity of intraluminal lysis of 123I-fibrinogen-labeled thrombus in an in vivo thrombus model. Conventional balloon angioplasty was also assessed in this model as a nonpharmacologic, mechanical control. In addition, all five techniques were compared with respect to the quantity and efficiency of intramural urokinase deposition at coronary angioplasty sites. In the in vivo thrombolysis experiments, the quantity of artificial clot lysis measured 6.8% for systemic therapy, 20.8% for guiding catheter infusion, 25.2% for Roubin catheter infusion, 62.8% for Dispatch catheter infusion, 98.8% for hydrogel balloon delivery, and 53.6% for conventional balloon angioplasty. Both the Dispatch catheter and the hydrogel balloon resulted in more clot lysis than the systemic, guiding catheter, or Roubin catheter approaches (P < 0.05). In comparison with conventional balloon angioplasty, only the hydrogel balloon resulted in higher levels of thrombus dissolution (P < 0.05). In the intramural deposition studies, the efficiency of urokinase delivery was 0.0004% for systemic therapy, 0.004% for guiding catheter infusion, 0.004% for Roubin catheter infusion, 0.08% for Dispatch catheter infusion, and 1.8% for hydrogel balloon delivery. The Dispatch catheter resulted in higher intramural drug levels than did all other techniques (P < 0.05), whereas the efficiency of urokinase deposition was higher with the hydrogel balloon than with all other approaches (P < 0.05). In the porcine model, it is subsequently concluded that local delivery of urokinase by catheter-based techniques can result in more complete lysis of intraluminal thrombus by using similar or lower doses of drug than by using conventional urokinase infusion techniques. Mechanical deformation of thrombus, possibly to increase the surface area available for thrombolysis and to physically disrupt clot, may be an important component of the mechanism of site-specific thrombolysis, particularly with the hydrogel balloon. Local delivery techniques also deposit significant quantities of urokinase at balloon angioplasty sites, creating an intramural reservoir of drug that may result in prolonged local thrombolysis.

Management of intracoronary thrombosis complicating percutaneous transluminal coronary angioplasty

With technological advances in equipment and increased experience of operators, the success rates of percutaneous transluminal coronary angioplasty (PTCA) now exceed 90%. However, acute periprocural occlusion continues to complicate approximately 6% of all procedures, and many of these occlusions are due to intracoronary (IC) thrombus. Patients at highest risk for this complication include those with acute ischemic syndromes or with angiographically apparent thrombus. These individuals may be candidates for the use of prolonged heparin infusions prior to dilatation, intracoronary thrombolytic therapy, or monoclonal antibody directed against the platelet glycoprotein IIb/IIIa receptor. All patients undergoing PTCA should receive adequate antiplatelet therapy, including aspirin, and heparin with dosing monitored by activated clotting times (ACT). In addition, some recommend the use of ionic contrast material. When IC thrombus accumulates following intervention, initial therapy should include IC nitroglycerin followed by a combination of redilatation and IC urokinase infusion. Prolonged balloon inflations may be useful, particularly with the use of autoperfusion catheters. Platelet glycoprotein IIb/IIIa receptor antagonists may prove to be beneficial in this situation as well. If the patient's clinical status deteriorates in spite of these measures, emergency coronary artery bypass graft surgery may be required.

Lesion-directed administration of alteplase with intracoronary heparin in patients with unstable angina and coronary thrombus undergoing angioplasty

Percutaneous coronary revascularization in patients with unstable angina and coronary thrombus carries a high complication rate. A new strategy to reduce thrombus burden before revascularization was tested in a multicenter prospective trial. Patients with unstable angina and coronary thrombus (n = 45) received alteplase through an infusion catheter at the proximal aspect of the target lesion and concomitant intracoronary heparin via a standard guiding catheter. Angiography was performed before and alter lesion-directed therapy and post-intervention. Systemic fibrinogen depletion and thrombin activation were not observed, while fibrinolysis was evident for > or = 4 hr after treatment. Target lesion stenosis did not change significantly after lesion-directed therapy, but thrombus score was reduced, particularly among patients who had large thrombi (mean 2.2 vs. 1.6, P = 0.02). Revascularization was successful in 89% of patients. Median final stenosis was 30% and mean final thrombus score was 0.4. Complications included recurrent ischemia (11%), MI (7%), abrupt closure (7%), severe bleeding (4%), and repeat emergency angioplasty (2%). Patients with overt thrombus appeared to derive the most angiographic benefit from lesion-directed alteplase plus intracoronary heparin. Later revascularization was highly successful. This strategy may be a useful adjunct to percutaneous revascularization for patients with unstable angina and frank intracoronary thrombus.

Efficacy of angioscopy in determining the effectiveness of intracoronary urokinase and TEC atherectomy thrombus removal from an occluded saphenous vein graft prior to stent implantation

Percutaneous revascularization of thrombus containing saphenous vein grafts is associated with a high incidence of acute complications. This case report describes successful revascularization of an occluded vein graft employing angioscopically guided sequential urokinase infusion, TEC atherectomy and stent implantation.

Angioplasty of complex lesions in ischemic rest angina: results of the Thrombolysis and Angioplasty in Unstable Angina (TAUSA) trial

OBJECTIVES

This study sought to analyze the role of complex lesion morphology on the acute results of angioplasty.

BACKGROUND

Acute complications of angioplasty are higher in unstable than in stable angina. The unstable culprit lesion is usually complex, indicative of plaque disruption and thrombus formation. Previous nonrandomized studies have shown that the presence of intracoronary thombus increases morbidity after coronary angioplasty. The role of complex morphology in coronary angioplasty outcome was studied in a prespecified subgroup analysis of a large multicenter coronary angioplasty trial.

METHODS

The results of coronary angioplasty from the Thrombolysis and Angioplasty in Unstable Angina (TAUSA) trial were analyzed. This large trial randomized 469 patients in double-blinded manner to receive either intracoronary urokinase or placebo during coronary angioplasty of the culprit lesion in ischemic rest angina with or without recent infarction. The study presented here analyzes in detail the results of coronary angioplasty in complex versus simple lesions in the urokinase and placebo groups. Complex lesions were defined before angioplasty by a core laboratory as having one or more of the following: irregular borders, overhanging edges, ulcerations or intraluminal filling defects proximal or distal to the lesion.

RESULTS

Of the 469 patients, 458 had identifiable culprit lesions, of which 245 were complex and 213 were simple. Complex lesions were associated with a higher abrupt closure rate than simple lesions (10.6% vs. 3.3%, respectively, p < 0.003). Patients with complex lesions also had higher recurrent in-hospital angina (p < 0.02) and emergent bypass surgery (p < 0.02). Further analysis of complex lesions revealed that abrupt closure was particularly high in the urokinase group (15.0% vs 5.9% for the placebo group, p < 0.03), and most abrupt closures were thrombotic. Composite clinical end points were also significantly higher with complex lesions and urokinase. In the placebo group, complex lesions had a higher abrupt closure rate as well as postcoronary angioplasty filling defects, but clinical end points were not significantly different.

CONCLUSIONS

Complex lesions before coronary angioplasty increase acute complication rates after coronary angioplasty. Urokinase as administered in the TAUSA trial had significant adverse effects, especially in complex lesions. However, even in the placebo arm, complex lesions were associated with higher complication rates than simple lesions. Newer antithrombotic measures that particularly target the platelet may eventually decrease complication rates in these lesions.

Impairment of fibrinolysis by streptokinase, urokinase and recombinant tissue-type plasminogen activator in the presence of radiographic contrast agents

OBJECTIVES

The purpose of this study was to determine whether an adverse interaction exists between radiographic contrast agents and thrombolytic drugs.

BACKGROUND

Coronary thrombosis may occur in the setting of unstable angina and after coronary angioplasty. However, the use of thrombolytic drugs in the setting of unstable angina has not been beneficial and, in one large trial of angioplasty in patients with unstable angina, was associated with an increased incidence of ischemic complications and abrupt closure. The reasons for these results are not clear. Coronary arteriography was performed in many of these trials, and it is known that fibrin structure and assembly are altered by radiographic contrast agents.

METHODS

Blood samples were obtained from patients before (n = 25) and after (n = 20) angiography using iohexol. Blood samples obtained before angiography were tested for response to streptokinase (10 and 100 IU/ml), urokinase (100, 200 and 500 IU/ml) and recombinant tissue-type plasminogen activator (rt-PA) (100 and 1,000 IU/ml) and the results measured. Iohexol, diatrizoate or ioxaglate (4% by volume) was added to separate aliquots of the baseline sample, and the test was repeated. Blood samples obtained after angiography were tested in a similar manner.

RESULTS

The onset of lysis at baseline by rt-PA at 1,000 IU/ml occurred at 72 +/- 8.2 s (mean +/- SD) and was markedly delayed in the presence of diatrizoate (527 +/- 181.7 s, p < 0.001) or iohexol (460 +/- 197.0 s, p < 0.001) but not ioxaglate. At 100 IU/ml, there was no lysis detected with rt-PA after the addition of any contrast agent. The addition of a contrast agent caused similar delays in the onset of lysis by urokinase and streptokinase; similar to rt-PA, the effect was smaller at higher concentrations of drug. In vivo blood samples obtained from the patient after angiography showed delays in the onset of lysis by rt-PA and urokinase but not streptokinase.

CONCLUSIONS

These data demonstrate that radiographic contrast agents impede fibrinolysis. This previously undescribed interaction was demonstrated using an in vitro test system, but these findings may have clinical relevance when thrombolytic drugs are used at the time of angiography.

Enhanced intracoronary thrombolysis with urokinase using a novel, local drug delivery system. In vitro, in vivo, and clinical studies

BACKGROUND

Current pharmacological regimens for treating intracoronary thrombus in the cardiac catheterization laboratory generally involve the administration of thrombolytic agents that result in a systemic fibrinolytic state and/or require prolonged arterial drug infusion. The purpose of the present study was to assess a new technique for treating intracoronary thrombus consisting of the local infusion of limited quantities of urokinase with a novel drug delivery device.

METHODS AND RESULTS

THe Dispatch coronary infusion catheter is a new local drug delivery system that allows for the prolonged infusion of therapeutic agents at an angioplasty site while distal coronary flow is maintained. Three experimental protocols were performed to determine the in vitro, in vivo, and clinical efficacy of this device. First, in vitro thrombolysis of fresh, porcine thrombus trapped in a 4-mm plastic tube with a 50% constriction and perfused with 20% porcine plasma was measured. Twenty-three thrombi were weighed before and after no treatment (n = 5), "systemic" urokinase administration (n = 4), local infusion of 150,000 U urokinase with a standard end-hole catheter (n = 4), local infusion of saline with the Dispatch catheter (n = 5), and local infusion of 150,000 U urokinase with the Dispatch catheter (n = 5). Second, 25 porcine coronary arteries in 23 pigs were dilated in vivo with conventional balloon angioplasty and then treated with 123I-labeled urokinase that was administered either by the Dispatch catheter (150,000 U; n = 16), intravenous systemic bolus (1,000,000 U; n = 3), guiding catheter infusion (500,000 U; n = 3), or local end-hole catheter infusion (150,000 U; n = 3). All vessels were subsequently harvested to quantify intramural deposition and subsequent washout of urokinase at the angioplasty site. Finally, 19 patients with angiographic evidence of intracoronary thrombus were treated with local urokinase infusion with the Dispatch catheter either before or after balloon angioplasty or directional atherectomy. In vitro studies demonstrated that infusion of urokinase with the Dispatch catheter decreased thrombus weight by 66% compared with no treatment (-25%), "systemic" urokinase administration (25%), end-hole catheter urokinase infusion (32%), or infusion of saline by the Dispatch catheter (32%) (P < or = .005). In vivo studies demonstrated immediate deposition of 0.12% of the urokinase delivered by the Dispatch catheter to the angioplasty site, compared with 0.0007% with systemic bolus, 0.003% with guiding catheter infusion, and 0.007% with local infusion with an end-hole catheter (P < .001). Urokinase deposited by the Dispatch catheter persisted intramurally for at least 5 hours. Patient studies demonstrated reduction of thrombus-containing stenoses and complete disappearance of intracoronary thrombus in all cases in which 150,000 U urokinase was locally infused over 30 minutes. There was no evidence of abrupt closure, distal embolization, or no reflow in any patient.

CONCLUSIONS

Local urokinase delivery with the Dispatch catheter can result in rapid and complete intracoronary thrombolysis using substantially less drug than standard thrombolytic techniques. Intramural deposition of drug with this technique creates a local reservoir of urokinase that may provide prolonged thrombolytic activity at the infusion site.

Use of half (disarticulated) Palmaz-Schatz stents for thrombus-containing coronary lesions

Coronary stenoses associated with thrombus can lead to poor angioplasty results and increased procedural complications. Stenting in the presence of thrombus is associated with an increased risk of stent thrombosis. We report eight patients in whom half a Palmaz-Schatz stent was implanted for inadequate angioplasty results owing to thrombus. Stenting resulted in improved angioplasty results; no stent thrombosis occurred.

Efficacy of adjunctive thrombolytic therapy in percutaneous transluminal coronary angioplasty

Adjunctive thrombolysis has not been shown to improve angioplasty success or complication rates in elective angioplasty or myocardial infarction and may be detrimental in unstable angina. Thrombolysis of chronically occluded vessels achieves recanalization at a rate comparable to conventional angioplasty and is associated with a high rate of complications and limited long-term patency. Thrombolysis administered for thrombus or acute occlusion complicating angioplasty usually achieves coronary artery patency but is unable to forestall complications in many cases. A benefit of thrombolysis in reducing restenosis has not been conclusively demonstrated.

Treatment of intracoronary thrombus with local urokinase infusion using a new, site-specific drug delivery system: the Dispatch catheter

BACKGROUND

The presence of intracoronary thrombus significantly increases the risk of conventional balloon angioplasty because of a high incidence of abrupt closure, distal embolization, and no-reflow phenomenon. The purpose of this study was to assess a new technique for treating intracoronary thrombus consisting of the local delivery of urokinase directly to the angioplasty site with a novel, catheter-based, drug delivery system.

METHODS

The Dispatch catheter is a new local, drug-delivery device that allows for the prolonged infusion of therapeutic agents at an angioplasty site while still maintaining distal coronary perfusion. Six patients with angiographic or clinical evidence of intracoronary thrombus were treated with 150,000 units of urokinase over a 30-min period using this device prior to or following conventional balloon angioplasty and/or directional atherectomy.

RESULTS

Successful delivery of urokinase directly to the angioplasty site was achieved in all 6 patients without hemodynamic or electrocardiographic compromise. In all six cases, local urokinase therapy resulted in complete dissolution of angiographic intracoronary thrombus and/or reduction of the coronary stenosis. Limited ischemia due to side-branch occlusion by the catheter's coils was noted in one patient. Distal embolization or no-reflow phenomenon were not observed in any case.

CONCLUSION

The local drug-delivery catheter used in this study was able to successfully and rapidly achieve intracoronary thrombolysis by delivering limited quantities of urokinase directly to the angioplasty site, while still maintaining distal coronary perfusion. This technique of local, thrombolytic drug delivery may be useful in the percutaneous treatment of intracoronary thrombus and thrombus-containing stenoses.

Inhibition of platelet deposition and lysis of intracoronary thrombus during balloon angioplasty using urokinase-coated hydrogel balloons

BACKGROUND

Conventional balloon angioplasty of intracoronary thrombus is associated with a high incidence of abrupt closure, distal embolization, and no-reflow phenomenon. The purpose of this study was to assess a new technique for treating intracoronary thrombus consisting of the local delivery of urokinase directly to the angioplasty site with urokinase-coated hydrogel balloons.

METHODS AND RESULTS

We assessed local urokinase delivery using hydrogel balloons in four protocols. First, we evaluated the pharmacokinetics of urokinase delivery in vitro using 125I-labeled urokinase to measure drug loading onto hydrogel balloons, drug retention by the hydrogel polymer during blood exposure, and drug transfer from the balloon surface to the arterial wall during balloon dilatation. Second, we measured 125I-urokinase washoff from the hydrogel balloon in the intact circulation and intramural drug delivery during in vivo balloon angioplasty in 10 anesthetized New Zealand rabbits. Third, we assessed the effect of local urokinase delivery on 111In-labeled platelet deposition after balloon angioplasty in vivo in 13 porcine carotid or iliac arteries dilated with urokinase-coated balloons and compared them with contralateral control arteries dilated with saline-coated balloons. Finally, we determined the clinical efficacy of urokinase-coated balloons in 15 patients with intracoronary thrombus, including 7 who demonstrated abrupt thrombotic closure after conventional angioplasty. Between 241 and 1509 U urokinase could be loaded onto hydrogel balloons ranging in size from 2 to 8 mm. In vitro and in vivo studies demonstrated that hydrogel balloons absorbed significantly more urokinase and demonstrated less drug wash-off than nonhydrogel balloons (P < .01). Similarly, both in vitro and in vivo studies demonstrated urokinase transfer from the hydrogel to the arterial wall during balloon angioplasty, with greater intramural drug deposition with larger balloons (P < .01). Local urokinase delivery after in vivo porcine angioplasty decreased 111In-labeled platelet deposition by 47% compared with contralateral control vessels (P = .03). Use of urokinase-coated balloons in patients with intracoronary thrombus resulted in thrombus dissolution and reversal of abrupt closure in all cases, without evidence of distal embolization.

CONCLUSIONS

With the use of hydrogel-coated balloons, urokinase can be delivered locally to an angioplasty site. This technique decreases platelet deposition after in vivo balloon angioplasty and is efficacious in treating intracoronary thrombus in patients, including those with abrupt thrombotic closure.

Prolonged intracoronary infusion of streptokinase: an alternative pharmacologic approach to extensive thrombus in native coronary artery

Several reports suggest that pretreatment of intracoronary thrombus with fibrinolytic agents may reduce the risk for complications during subsequent balloon angioplasty. We report a case, for the first time, of successful lysis of an extensive thrombus in a native coronary artery by administering a prolonged intracoronary infusion of streptokinase to facilitate subsequent angioplasty and discuss the management strategy when intracoronary thrombus is encountered.

Adjunctive thrombolytic therapy during angioplasty for ischemic rest angina. Results of the TAUSA Trial. TAUSA Investigators. Thrombolysis and Angioplasty in Unstable Angina trial

BACKGROUND

Acute closure is increased after angioplasty in unstable angina, and adjunctive intracoronary thrombolytic therapy has been used successfully to increase angiographic success. The role of prophylactic thrombolytic therapy during angioplasty in unstable angina is unknown.

METHODS AND RESULTS

Four hundred sixty-nine patients with ischemic rest pain with or without a recent (< 1 month) infarction were randomized in double-blind fashion to intracoronary urokinase or placebo. Randomization was carried out in two sequential phases. In phase I, 257 patients were randomized to 250,000 U of urokinase or placebo given in divided doses at the time of angioplasty. In phase II, 212 patients were randomized to 500,000 U of urokinase or placebo in divided doses. All patients were pretreated with aspirin, and activated clotting times were followed to maintain them at > 300 seconds during angioplasty. Angiographic end points of thrombus after angioplasty were insignificantly decreased by urokinase (30 [13.8%] versus 41 [18.0%] with placebo; P = NS). Acute closure, on the other hand, was increased with urokinase (23 [10.2%] versus 10 [4.3%] with placebo; P < .02). The difference in acute closure between urokinase and placebo was more striking at the higher dose of urokinase (P < .04) than in phase I at the lower urokinase dose (P = NS). Adverse in-hospital clinical end points (ischemia, infarction, or emergency coronary artery bypass surgery) were also increased with urokinase versus placebo (30 [12.9%] versus 15 [6.3%], respectively; P < .02). Angiographic and clinical end points were worse with urokinase in unstable angina without recent infarction than with angioplasty after a recent infarction.

CONCLUSIONS

Adjunctive urokinase given prophylactically during angioplasty for ischemic rest angina as administered in this trial is associated with adverse angiographic and clinical events. These detrimental effects may be related to hemorrhagic dissection, lack of intimal sealing, or procoagulant or platelet-activating effects of urokinase.

Febrile reaction associated with urokinase

Urokinase is an endogenously produced human proteolytic enzyme used to treat many thrombotic disorders. A 54-year-old man with recurrent myocardial infarction experienced fever during intracoronary urokinase infusion into a saphenous vein graft; the fever resolved after discontinuation of the infusion. After excluding all other possible etiologies of fever, urokinase was determined to be the cause. Several studies indicated that this reaction may be associated with urokinase infusion, but it is actually recognized by few individuals. This is the first published case report of the adverse event to our knowledge.

Thrombolysis as an adjunct to angioplasty

Acute coronary occlusion following angioplasty is a significant cause of in-hospital morbidity and mortality. Following acute closure, several strategies can be used to reopen the artery, including redilation, adjunctive thrombolysis, or other interventional techniques. Definite indications for thrombolysis as an adjunct to angioplasty include (1) recently occluded saphenous vein grafts, patent native vessels, or saphenous grafts with abundant intracoronary thrombus; and (2) acute closure during angioplasty, which is presumably secondary to thrombus formation and resistant to redilation alone.

Experience with directional coronary atherectomy since pre-market approval

Directional coronary atherectomy (DCA) received Food and Drug Administration (FDA) Pre-Market Approval in September 1990 and was then released through formal training certification of physicians at each new site. Procedure volume has increased dramatically since approval, with > 17,000 DCA procedures performed in 1991 and a cumulative total of > 33,000 procedures by mid-1992, at > 670 centers in the United States. Clinical application and results since approval have generally been similar to preapproval multicenter investigational results. Comparison of pre- and postapproval usage at the Medical College of Virginia shows similar baseline characteristics and indications, although recent patients show a higher proportion of "salvage" DCA for failed or suboptimal angioplasty (6% vs 14%) or DCA in combination with multidevice multiple vessel intervention (30% vs 38%). Overall results in 300 patients and 345 procedures included procedural success in 95%, clinical success in 94%, with major complications in 4.6% (including urgent bypass surgery in 3.8%, Q wave myocardial infarction in 1.7%, and hospital mortality in 0.3%). Results before and after FDA approval were similar for procedural success (94% vs 96%), clinical success rate (94% vs 94%), and major complications (5.5% vs 4.4%). There was a trend toward lower urgent surgery rate (5.4% vs 3.3%) in the more recent experience. In addition to its established efficacy for highly eccentric lesions, newer applications for which DCA is being used following FDA approval include treatment of saphenous vein grafts, thrombus-associated lesions, aorto-ostial lesions, failed or suboptimal percutaneous transluminal coronary angioplasty result, bifurcation lesions, and use as part of multivessel intervention.(ABSTRACT TRUNCATED AT 250 WORDS)

Excimer laser-assisted coronary angioplasty for lesions containing thrombus

OBJECTIVES

The purpose of this study was to analyze the success rates for excimer laser-assisted coronary angioplasty performed in patients undergoing angioplasty for lesions containing thrombus.

BACKGROUND

The presence of intracoronary thrombus increases the risk of a poor clinical outcome after balloon angioplasty. The effect of intracoronary thrombus on the safety and efficacy of excimer laser-assisted coronary angioplasty is unknown.

METHODS

Percutaneous excimer laser-assisted coronary angioplasty was attempted in 142 patients, of whom 12 had angiographic evidence of intracoronary thrombus in 14 lesions, defined as a filling defect surrounded by contrast medium or an area of contrast staining.

RESULTS

Clinical success (< 50% residual stenosis without myocardial infarction, death or bypass surgery at any time during hospitalization) was achieved in 7 (58%) of the 12 patients with intracoronary thrombus, compared with 123 (95%) of the 130 patients without thrombus (p = 0.00001). Angiographic and clinical complications were more common in patients with thrombus: embolization (25% vs. 1%, p < 0.001), myocardial infarction (33% vs. 2%, p < 0.001), abrupt closure (17% vs. 4%, p = 0.049). Angiographic restenosis at 6 months was seen at 7 (70%) of 10 treated sites with intracoronary thrombus and at 59 (51%) of 116 sites without thrombus (p = 0.245). Presence of intracoronary thrombus was identified as the most important predictor of clinical success (p = 0.013) by multivariable logistic regression analysis, which controlled for other co-variables, such as lesion complexity or lesion location in a saphenous vein graft.

CONCLUSIONS

This analysis shows that the success of excimer laser-assisted coronary angioplasty is compromised when thrombus is detected angiographically. Further investigation of other strategies is needed to improve the outcome of angioplasty for this challenging problem.

Laser facilitated angioplasty and thrombolysis in acute myocardial infarction complicated by prolonged or recurrent chest pain

To date, application of laser angioplasty in acute myocardial infarction (MI) has not been reported. In nine patients with acute myocardial infarction complicated by continuous or recurrent severe ischemia and chest pain, a mid-infrared, solid-state, pulse-wave holmium/thulium:YAG coronary laser was applied. In six of these patients the laser was specifically utilized for the purpose of coronary thrombolysis. In each case a guidewire was placed across the stenosis and a multifiber laser catheter was utilized, emitting 250-600 mJ/pulse at 5 Hz, followed by adjunctive balloon angioplasty. Laser success (defined as ability to cross the lesion, reduction of > or = 20% in stenosis and thrombolysis when a thrombus is present) was achieved in all patients. Final angiograms revealed residual stenosis < or = 30%, adequate thrombolysis and no major complication (MI, perforation, emergency CABGS, CVA, death) in each patient. Clinically, all nine patients improved, survived the acute infarction and were discharged. This initial clinical experience demonstrates the feasibility and safety of holmium/thulium:YAG laser application in thrombolysis and plaque ablation in selected patients who experience acute myocardial infarction complicated by prolonged or recurrent ischemia and chest pain.