Heparin delivery at the site of angioplasty with a novel drug delivery sleeve

Local delivery of heparin post-PTCA: a multicenter randomized pilot study

Bailout stenting for major dissection and threatened closure has high rates of ischemic complications. We performed a randomized trial of local heparin delivery using the infusion sleeve before bailout stenting for suboptimal angioplasty results. In phase I, 20 patients were randomized to local delivery with either 40- or 100-psi infusion pressure. In phase II, 37 patients were randomized to local delivery at 100 psi or standard therapy. Local delivery succeeded in all but one patient; overall there was no significant worsening of intimal dissection. One patient treated with 100-psi drug infusion suffered a perforation after stent placement. There were no significant differences in the composite endpoint of death, MI, CABG, urgent repeat angioplasty, and stent thrombosis at 30 days (21% vs. 0%; P = 0.18). At 6 months, the rates of myocardial infarction in phase II were 27% with local delivery vs. 10% with standard treatment (P = 0.4). Local heparin delivery in dissected vessels may be associated with increased complications and should be approached with caution.

Local drug delivery: impact of pressure, substance characteristics, and stenting on drug transfer into the arterial wall

Injection parameters for local drug delivery are frequently determined by studies with marker substances. However, the pharmacologic properties of the actual drug may influence delivery efficiency and lead to different results. Aim of this study was to assess the delivery capacities of two device-drug combinations in order to verify this approach for further in vivo studies. Tritiated (3H) preparations (5 ml) of the hydrophylic low-molecular-weight heparin reviparin and the lipophilic taxane paclitaxel were injected into the left anterior descending artery of freshly explanted porcine hearts with the Infusasleeve II catheter system. A balloon support pressure of 6 atm and infusion pressures of 40, 60, 80, or 100 psi were used. In three additional groups, reviparin was injected following stent implantation and paclitaxel was injected prior to or following stent implantation. Arteries along with surrounding myocardium were harvested. The artery was carefully dissected, and artery and myocardium were separately homogenized, and activity was measured. Of the totally delivered activity, 0.09%+/-0.03% (40 psi) to 0.17%+/-0.13% (100 psi) of reviparin and 2.03%+/-0.67% (60 psi) to 2.68%+/-1.57% (100 psi) of paclitaxel were found in the vessel wall. The results for different injection pressures were not significantly different for either drug. The percentage activity delivered to the vessel wall was substantially larger in the paclitaxel group as compared to reviparin delivery (P < 0.01 at 60, 80, and 100 psi). The mean concentration of reviparin in the artery was 20 to 33 times higher than in the myocardium. For paclitaxel the factors were 110 to 243. Stent implantation prior to or following local delivery did not result in a different delivery efficiency. The results demonstrate that the characteristics of the delivered drug contribute largely to the delivery efficiency. Using identical injection parameters, drug concentrations in the arterial wall were significantly higher for the lipophilic paclitaxel as compared to the hydrophilic reviparin. Stenting of the artery did not influence delivery efficiency.

Local heparin delivery prior to coronary stent implantation: acute and six-month clinical and angiographic results

Stents increase smooth muscle cell proliferation, which may also lead to in-stent restenosis. A local delivery strategy provides higher drug concentration at the angioplasty site and may limit the proliferative response following stenting. Local heparin delivery was attempted in 35 patients following balloon angioplasty using an "over-the-balloon" style catheter (infusion sleeve). The infusion sleeve was successfully tracked and heparin was delivered in 33 (94%) patients. Heparin (1,000 IU/ml) was delivered under low (45 psi, 2 ml, n = 4), intermediate (75 psi, 4 ml, n = 11), and high (100 psi, 4 ml, n = 18) proximal infusion pressures. Stent placement was successful in all cases. Acute and in-hospital complications were a severe arterial spasm after heparin delivery, a non Q-wave myocardial infarction, and two vascular complications. Ten dissections were observed after PTCA and prior to heparin delivery. Of these dissections, 7 remained unchanged, 2 worsened, and 1 improved with local delivery. When heparin was delivered in the absence of dissection, no new dissections were observed. Of the 33 patients who received heparin, 30 (91%) had no symptoms and a negative exercise test at clinical follow-up. QCA analysis of 6-month follow-up angiograms, performed in 32 of 33 (97%) patients, demonstrated an acute gain of 1.98 +/- 0.67 mm, a late loss of 0.94 +/- 0.78 mm, a net gain of 1.04 +/- 0.78 mm, and a loss index of 0.48 +/- 0.32. Restenosis (> or = 50% stenosis) was observed in 4 of 32 (12%) patients. Local delivery of heparin via the infusion sleeve following PTCA and prior to stent deployment is feasible with an acceptable safety profile and a low clinical and angiographic restenosis rate at 6 months.