Impact of routine angiographic follow-up on the clinical benefits of paclitaxel-eluting stents: results from the TAXUS-IV trial

OBJECTIVES

The objectives of the study were to evaluate the effect of angiographic follow-up on revascularization rates in the TAXUS-IV trial and to determine whether the relative benefit of paclitaxel-eluting stent implantation compared with bare metal stent implantation was modified by angiographic follow-up.

BACKGROUND

Although several clinical trials have demonstrated that drug-eluting stents (DES) reduce restenosis compared with bare-metal stents (BMS), virtually all of these studies have incorporated angiographic follow-up.

METHODS

In the TAXUS-IV trial, 1,314 percutaneous coronary intervention patients were randomized to receive paclitaxel-eluting stents (PES) (n = 662) or identical-appearing BMS (n = 652). Clinical outcomes were compared, stratified by assignment to angiographic follow-up or clinical follow-up alone.

RESULTS

Compared with clinical follow-up alone, angiographic follow-up patients had a significantly higher rate of target vessel revascularization (TVR) at 1 year (adjusted hazard ratio [HR] 1.46; p = 0.04), with similar relative increases in PES and BMS patients. Because PES reduced TVR by approximately 60% regardless of type of follow-up, assignment to angiographic follow-up tended to overestimate the absolute benefit of PES relative to clinical follow-up alone. In contrast, assessment of end points immediately before the time of follow-up angiography led to substantial underestimation of the absolute benefit of PES implantation.

CONCLUSIONS

Performance of mandatory angiographic follow-up increases rates of TVR among patients receiving both BMS and PES and overestimates the absolute clinical benefits of PES relative to clinical follow-up alone. Nonetheless, PES substantially reduces TVR regardless of assignment to mandatory angiographic follow-up or not. Future studies designed to determine the true clinical benefits of DES should either forgo routine angiographic follow-up or separate the time of repeat angiography from the primary clinical end point by as long as possible.

A randomized, controlled trial of saphenous vein graft intervention with a filter-based distal embolic protection device: TRAP trial

The purpose of this prospective, multicenter trial was to evaluate the safety and effectiveness of the TRAP Vascular Filtration System (VFS) to reduce embolic complications during stenting of diseased saphenous vein grafts (SVGs). Patients with SVG lesions were randomly assigned to undergo stenting with or without the TRAP device. The trial was designed to enroll 752 randomized patients. However, the sponsor terminated the study after a total of 467 patients (358 randomized) were enrolled because of poor recruitment once another distal protection device was approved for clinical use. The primary study endpoint, major adverse cardiac events at 30 days, occurred in 17.3% of control patients and 12.7% of patients treated with the TRAP device (P = 0.24). There was a trend toward a lower incidence of myocardial infarction in the TRAP group compared with the control group (16.2% vs 10.5%, P = 0.12). This difference was predominantly due to a lower incidence of moderate-large infarction (CKMB >5x) in the TRAP group. Use of the TRAP VFS during SVG intervention was safe and was associated with a trend toward a lower incidence of adverse events, however, due to low enrollment the study lacked sufficient power to detect a significant benefit with the device.

Comparison of a polymer-based paclitaxel-eluting stent with a bare metal stent in patients with complex coronary artery disease: a randomized controlled trial

CONTEXT

Compared with bare metal stents, drug-eluting stents reduce restenosis in noncomplex lesions. The utility of drug-eluting stents has not been evaluated in more difficult stenoses.

OBJECTIVE

To investigate the safety and efficacy of the polymer-based, slow-release paclitaxel-eluting stent in a patient population with more complex lesions than previously studied.

DESIGN, SETTING, AND PATIENTS

Prospective, placebo-controlled, double-blind, multicenter randomized trial conducted from February 2003 to March 2004 at 66 academic and community-based institutions with 1156 patients who underwent stent implantation in a single coronary artery stenosis (vessel diameter, 2.25-4.0 mm; lesion length, 10-46 mm), including 664 patients (57.4%) with complex or previously unstudied lesions (requiring 2.25-mm, 4.0-mm, and/or multiple stents) and 9-month clinical and angiographic follow-up.

INTERVENTIONS

Patients were randomly assigned to receive 1 or more bare metal stents (n = 579) or identical-appearing paclitaxel-eluting stents (n = 577).

MAIN OUTCOME MEASURE

Ischemia-driven target vessel revascularization at 9 months.

RESULTS

Baseline characteristics were well matched. Diabetes was present in 31% of patients. The mean (SD) reference vessel diameter was 2.69 (0.57) mm, the reference lesion length was 17.2 (9.2) mm, and 78% of lesions were type B2/C. A mean (SD) of 1.38 (0.58) stents (total mean [SD] length, 28.4 [13.1] mm) were implanted per lesion; 33% of lesions required multiple stents. Stents that were 2.25 mm and 4.0 mm in diameter were used in 18% and 17% of lesions, respectively. Compared with bare metal stents, paclitaxel-eluting stents reduced the 9-month rate of target lesion revascularization from 15.7% to 8.6% (P<.001) and target vessel revascularization from 17.3% to 12.1% (P = .02). Similar rates were observed for cardiac death or myocardial infarction (5.5% for bare metal stent group vs 5.7% for paclitaxel-eluting stent group) and stent thrombosis (0.7% in both groups). Angiographic restenosis was reduced from 33.9% to 18.9% in the entire study cohort (P<.001), including among patients receiving 2.25-mm stents (49.4% vs 31.2%; P = .01), 4.0-mm stents (14.4% vs 3.5%; P = .02), and multiple stents (57.8% vs 27.2%; P<.001).

CONCLUSION

Compared with a bare metal stent, implantation of the paclitaxel-eluting stent in a patient population with complex lesions effectively reduces clinical and angiographic restenosis.

Early and sustained dual oral antiplatelet therapy following percutaneous coronary intervention: a randomized controlled trial

CONTEXT

Following percutaneous coronary intervention (PCI), short-term clopidogrel therapy in addition to aspirin leads to greater protection from thrombotic complications than aspirin alone. However, the optimal duration of combination oral antiplatelet therapy is unknown. Also, although current clinical data suggest a benefit for beginning therapy with a clopidogrel loading dose prior to PCI, the practical application of this therapy has not been prospectively studied.

OBJECTIVES

To evaluate the benefit of long-term (12-month) treatment with clopidogrel after PCI and to determine the benefit of initiating clopidogrel with a preprocedure loading dose, both in addition to aspirin therapy.

DESIGN, SETTING, AND PARTICIPANTS

The Clopidogrel for the Reduction of Events During Observation (CREDO) trial, a randomized, double-blind, placebo-controlled trial conducted among 2116 patients who were to undergo elective PCI or were deemed at high likelihood of undergoing PCI, enrolled at 99 centers in North America from June 1999 through April 2001.

INTERVENTIONS

Patients were randomly assigned to receive a 300-mg clopidogrel loading dose (n = 1053) or placebo (n = 1063) 3 to 24 hours before PCI. Thereafter, all patients received clopidogrel, 75 mg/d, through day 28. From day 29 through 12 months, patients in the loading-dose group received clopidogrel, 75 mg/d, and those in the control group received placebo. Both groups received aspirin throughout the study.

MAIN OUTCOME MEASURES

One-year incidence of the composite of death, myocardial infarction (MI), or stroke in the intent-to-treat population; 28-day incidence of the composite of death, MI, or urgent target vessel revascularization in the per-protocol population.

RESULTS

At 1 year, long-term clopidogrel therapy was associated with a 26.9% relative reduction in the combined risk of death, MI, or stroke (95% confidence interval [CI], 3.9%-44.4%; P =.02; absolute reduction, 3%). Clopidogrel pretreatment did not significantly reduce the combined risk of death, MI, or urgent target vessel revascularization at 28 days (reduction, 18.5%; 95% CI, -14.2% to 41.8%; P =.23). However, in a prespecified subgroup analysis, patients who received clopidogrel at least 6 hours before PCI experienced a relative risk reduction of 38.6% (95% CI, -1.6% to 62.9%; P =.051) for this end point compared with no reduction with treatment less than 6 hours before PCI. Risk of major bleeding at 1 year increased, but not significantly (8.8% with clopidogrel vs 6.7% with placebo; P =.07).

CONCLUSIONS

Following PCI, long-term (1-year) clopidogrel therapy significantly reduced the risk of adverse ischemic events. A loading dose of clopidogrel given at least 3 hours before the procedure did not reduce events at 28 days, but subgroup analyses suggest that longer intervals between the loading dose and PCI may reduce events.

Comparison of self-expanding and balloon-expandable stents for the reduction of restenosis

To compare the efficacy of self-expanding (SE) and balloon-expandable (BE) stents in native coronary arteries, we randomly assigned 1,096 patients with new and restenotic lesions to receive either device. Baseline demographics and coronary angiographic characteristics were similar in the 2 groups. The incidence of major adverse cardiac events including death, myocardial infarction, bypass surgery, and repeat intervention was similar for both groups at 1 month (2.9% vs 3.1% for SE vs BE, respectively) and at 9 months (19.3% vs 20.1%, SE vs BE respectively). In a subgroup of patients who underwent follow-up angiography (n = 250), the binary restenosis rates (24.2% vs 18.7%, p = 0.30), late loss (0.98 vs 94 mm, p = 0.60), and loss index (0.55 vs 55, p = 0.95) were not significantly different for both groups. In 62 patients who underwent intravascular ultrasound examination (IVUS), there was a trend toward a lower incidence of edge tears in the SE group (6% vs 23%, p = 0.06). Follow-up IVUS analysis showed that the minimum stent area of the SE stent increased by 33% at 6 months, whereas no change occurred in the BE stents; this was accompanied by a greater degree of intimal proliferation in the SE stents compared with BE stents (3.1 +/- 2.0 vs 1.7 +/- 1.7 mm(2)). Thus, the SE stents had similar clinical and angiographic outcomes in patients with lesions in native coronary arteries.

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

Recanalization of a totally occluded saphenous vein graft (SVG) using commercially available urokinase from human kidney cells has been shown to be effective, but the duration of infusion and complications such as allergic reactions, bleeding events, and non-Q-wave myocardial infarction have limited its acceptance. Recently, genetic engineering has allowed the synthesis of recombinant urokinase (r-UK). Patients with an occluded SVG from 37 centers were randomized to receive a 6-hour infusion of either low-dose (125,000 IU/hour) or high-dose (350,000 IU/hour) r-UK followed by up to a maximum of 18 hours of r-UK (125,000 IU/hour) via a subselective catheter directly into the occluded vein graft. The primary study end point was final preintervention achievement of Thrombolysis In Myocardial Infarction (TIMI) flow > or = 2 using core angiographic analysis. One hundred seven patients were randomized and 98 received the study drug (low dose 52 patients, high dose 46 patients). TIMI flow > or = 2 after completion of the study drug was higher in the high-dose group (51% vs 24%, p = 0.019). This difference narrowed, but a trend was still evident on the final angiogram after adjunctive mechanical intervention (72% vs 58%, p = 0.254). Bleeding complications were frequent; severe or life-threatening bleeding occurred in 12% of patients on the low dose and 11% of patients on the high dose (p = NS), including 2 intracerebral bleeds, both of which were fatal with 1 in each group. Thus, in patients with an occluded SVG, a randomized trial of direct low-dose versus high-dose r-UK infusion demonstrated increased recanalization rates (TIMI flow > or = 2) in the high-dose arm. Percutaneous revascularization of SVG with r-UK can be accomplished with acceptable success rates, but complications are frequent.

Effect of direct thrombin inhibition with Bivalirudin (Hirulog) on restenosis after coronary angioplasty

The direct antithrombin, bivalirudin, did not reduce angiographic restenosis measured either as the dichotomous restenosis rate of 62% for bivalirudin and 58% for heparin (p = 0.70), or as the late loss in lumen diameter of 0.44 +/- 0.47 mm for bivalirudin and 0.39 +/- 0.53 mm for heparin (p = 0.62). Direct thrombin inhibition with bivalirudin neither reduces angiographic restenosis nor alters the impact of several established risk factors for restenosis.

PTCA using the right radial artery access site

In order to evaluate the right radial artery approach (RRA) in PTCA, our first 50 patients (pts) who had undergone PTCA from this access site were evaluated. Seventy-eight percent of pts were male, 68% had unstable angina or recent MI. Seventy-seven lesions were dilated (31 type A, 32 type B, 13 type C). Access time was 4.3 +/- 2.4 minutes (min). Six French Voda and multipurpose guide catheters were primarily utilized (mean 1.2 guides/case). Several different balloon types were used satisfactorily (mean 1.5 balloons/case). Sheaths were pulled 3.4 +/- 1.2 hours post-procedure when ACT was less than 200 seconds. Compression time was 24.8 +/- 11 and heparin was immediately resumed. No access site complications occurred. Results were compared to a cohort of 100 pts who had undergone PTCA from the right femoral artery approach (RFA). PTCA time, fluoroscopy time, contrast utilized, primary success rate, emergency bypass and cath lab charges were the same in both groups. Access site complications were significantly less in the right radial group (0 RRA vs. 4 RFA, p < .02). Post PTCA length of stay (1.9 +/- 0.3 vs. 3.4 +/- 0.6, p < .05) and total hospital length of stay (3.7 +/- 0.5 vs. 5.2 +/- 0.6, p < .05) were significantly less in the radial group. As a result of the shorter hospital stay, total hospital charge was less in the radial group (14,730 +/- 882 vs. 17,461 +/- 908, p < .05).

CONCLUSION

Results of PTCA performed from RRA are similar to those from RFA with a significant reduction in access site complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Infected femoral arteriovenous fistula after percutaneous insertion of an intra-aortic balloon

We have reported an infected arteriovenous fistula of the femoral artery after percutaneous intra-aortic balloon insertion. This case was successfully managed with extra-anatomic bypass followed by resection and drainage of the infected area.

Evaluating the radiographic assessment of pulmonary venous hypertension in chronic heart disease

This study evaluated how accurately the chest film could be used to determine pulmonary capillary wedge pressure (PCW) in patients with chronic heart disease. Six experienced readers interpreted the erect posteroanterior chest radiographs of 50 patients whose measured PCWs ranged from 6 to 38 mm Hg. Direct numeric estimates of PCW from the films were closely related to measured levels of PCW (r = 0.675). This linear correlation increased to 0.81 when individual-reader variations were reduced by taking a "consensus" (mean) of the six readers' estimates for each case. A combination of the judged degree of pulmonary blood flow redistribution (PFR) and three particular signs of pulmonary venous hypertension (PVH), basal and perihilar vascular blurring and alveolar edema, adequately summarized the radiographic information about PCW. These combined judgments of PFR/PVH identified films from patients with higher and lower PCW levels as accurately as readers' numeric estimates of PCW. Other radiographic signs (enlargement of the heart and central pulmonary vessels and the presence of Kerley lines or pleural effusion) were also positively related to increases in PCW, but added little to the information provided by the PFR/PVH criteria.