Low- versus high-dose recombinant urokinase for the treatment of chronic saphenous vein graft occlusion

A prospective double-blind randomized trial of urokinase flushes to prevent bacteremia resulting from luminal colonization of subcutaneous central venous catheters

PURPOSE

This study was undertaken to determine if central venous catheter (CVC)-related infection in children with cancer could be prevented by monthly flushing of the catheter with urokinase.

PATIENTS AND METHODS

Between August 1994 and July 1998, 103 patients with cancer were randomized at the time of subcutaneous CVC placement to receive monthly flushing of their catheters with either 5000 IU of urokinase-heparin or heparin alone. Patients subsequently had blood cultures taken from their CVCs during an episode of fever.

RESULTS

Seventy-four of the 103 patients (72%) enrolled in the study received at least 6 catheter flushes: 40 with urokinase-heparin and 34 with heparin. The median number of flushes was 9.5 in the urokinase-heparin group and 10.2 in the heparin-only group (P = 0.62). There were 5 positive blood cultures in the urokinase-heparin group and seven in patients receiving heparin alone (P = 0.27). Staphylococcus epidermidis was isolated from the blood of 3 patients receiving urokinase-heparin and 6 in those receiving heparin alone (P = 0.17).

CONCLUSION

Prophylactic monthly catheter flushes with 5000 IU urokinase did not significantly decrease the number of documented bacteremic events in children with cancer who have CVCs.

Distal filter protection during saphenous vein graft stenting: technical and clinical correlates of efficacy

OBJECTIVES

The aim of this study was to evaluate the clinical, angiographic, and technical factors related to successful stenting of diseased saphenous vein grafts (SVGs) using a novel filter-based distal protection device.

BACKGROUND

Protection of the distal microvasculature with a balloon occlusion and aspiration system has been shown to reduce atherothrombotic embolization and peri-procedural myocardial infarction (MI) after percutaneous coronary intervention (PCI) in SVGs. The safety, efficacy, and technical factors relating to procedural success with filter-based distal protection devices are unknown.

METHODS

Percutaneous coronary intervention was performed in 60 lesions in 48 patients undergoing SVG intervention with the FilterWire EX distal protection system in a phase I experience at six sites. A larger phase II study was then performed in 248 lesions in 230 SVGs at 65 U.S. centers.

RESULTS

Cumulative adverse events to 30 days occurred in 21.3% of patients in phase I, including a 19.1% rate of MI. Numerous anatomic, device-specific, and operator-related contributors to these adverse events were identified, resulting in significant changes to the protocol and instructions for use. Subsequently, despite similar clinical and angiographic characteristics to the phase I patients, the 30-day adverse event rate in phase II was reduced to 11.3% (p = 0.09), due primarily to a lower incidence of peri-procedural Q-wave and non-Q-wave MI.

CONCLUSIONS

Distal protection during SVG PCI with the FilterWire EX is associated with a low rate of peri-procedural adverse events compared to historical controls. A unique set of anatomic, technical, and operator-related issues exist with distal filters which, if ignored, may reduce their effectiveness.

Evaluation of a balloon occlusion and aspiration system for protection from distal embolization during stenting in saphenous vein grafts

Distal embolization after angioplasty in degenerated saphenous vein grafts (SVGs) results in high rates of periprocedural myonecrosis and mortality. Temporary protection of the distal microcirculation with aspiration of dislodged debris may improve the safety of SVG intervention. To evaluate the feasibility, safety, and efficacy of distal protection using the PercuSurge GuardWire Occlusion and Aspiration System, 103 consecutive patients undergoing planned stenting of 105 SVG lesions were prospectively enrolled in a multinational, multicenter study. Before angioplasty, protection of the distal circulation was achieved with the PercuSurge GuardWire distal balloon occlusion system, followed by stenting and debris aspiration. Quality assurance measures in the study included independent on-site data monitoring, clinical event adjudication, data analysis, and use of multiple core laboratories. Mean graft age was 8.9 +/- 4.0 years. The duration of distal balloon inflation was 5.4 +/- 3.7 minutes; premature balloon deflation for ischemia was not required in any patient. Macroscopically visible red and/or yellow debris was extracted in 91% of patients. By core lab analysis, postprocedural Thrombolysis In Myocardial Infarction-III flow was present in 98.9% of grafts (vs 83.5% before intervention). No patient developed angiographic evidence of no reflow or distal embolization. Postprocedural creatine phosphokinase MB isozyme levels were elevated to >3 x normal in only 5 patients (5%), and 97 patients (94%) were free of major adverse events at 30 days. We conclude that the GuardWire distal balloon occlusion and aspiration system is an effective and safe method for protecting distal microcirculation from the adverse consequences of embolization during mechanical intervention of degenerated SVGs.