Percutaneous treatment of coronary bifurcations: lesion preparation before provisional bare metal stenting and subsequent immunosuppression with oral prednisone. The IMPRESS-Y study

The many roles of cathepsins in restenosis

Drug-eluting stents (DES) and dual antiplatelet regimens have significantly improved the clinical management of ischemic heart disease; however, the drugs loaded with DES in clinical practice are mostly paclitaxel or rapamycin derivatives, which target symptoms of post implantation proliferation and inflammation, leading to delayed re-endothelialization and neo-atherosclerosis. Along with the treatments already in place, there is a need for novel strategies to lessen the negative clinical outcomes of DES delays as well as a need for greater understanding of their pathobiological mechanisms. This review concentrates on the function of cathepsins (Cats) in the inflammatory response and granulation tissue formation that follow Cat-induced damage to the vasculature scaffold, as well as the functions of Cats in intimal hyperplasia, which is characterized by the migration and proliferation of smooth muscle cells, and endothelial denudation, re-endothelialization, and/or neo-endothelialization. Additionally, Cats can alter essential neointima formation and immune response inside scaffolds, and if Cats are properly controlled in vivo, they may improve scaffold biocompatibility. This unique profile of functions could lead to an original concept for a cathepsin-based coronary intervention treatment as an adjunct to stent placement.

Noninvasive assessment of foot perfusion in cholesterol-fed rabbits using dynamic volume perfusion CT with an upslope method

To evaluate the feasibility of dynamic foot volume CT with the upslope method and to demonstrate macrovascular reactivity and microvascular perfusion during cuff-induced reactive hyperemia state in cholesterol-fed rabbits. 30 New Zealand male rabbits were divided into 2 groups: dietary hypercholesterolemia (n = 10) and normal diet control (n = 20). To measure for macrovascular reactivity, perfusion parameters of the left posterior tibial artery was measured at baseline and at reactive hyperemia state. For the evaluation of microvascular perfusion, color-coded perfusion map of the plantar dermis was generated for perfusion CT scan by an in-house developed dedicated analysis software based on upslope method. Dermal perfusion values were measured and analyzed before and after cuff-induced reactive hyperemia. Foot dynamic volume CT with the upslope method demonstrated significant impairment of both macrovascular reactivity and microvascular perfusion in cholesterol-fed rabbits without significant macrovascular lesions during cuff-induced reactive hyperemia (CRH) state. Arterial time-to-peak of cholesterol-fed rabbits failed to show acceleration while chow-fed rabbits showed significant decrease in time. Microvascular perfusion calculated by perfusion value (P < 0.01) and perfusion ratio (P = .014) showed decreased microvascular perfusion in cholesterol-fed rabbits compared to chow-fed rabbits during CRH state. Post-CT pathologic examination revealed decreased endothelial cell density in cholesterol-fed rabbits (P < 0.001). Foot perfusion CT using upslope method provides perfusion parameters for large arteries and a perfusion map of the foot during cuff-induced reactive hyperemia in cholesterol-fed rabbits. It may be a useful tool to assess microvascular reactivity in patients with peripheral artery disease but no apparent macrovascular lesions.

Use of endothelial progenitor capture cell stent during percutaneous treatment of coronary bifurcations: a prospective angiographic registry

BACKGROUND

The treatment of bifurcation lesions remains a challenge with poor immediate results and higher restenosis rate than in nonbifurcated lesions. Drug-eluting stents improve the outcome after coronary stenting, but are associated with a small but statistically significant increase in late and very late stent thrombosis. Thus, aim of the present study was to evaluate the angiographic and clinical results of a new type of stent (coated with murine monoclonal antihuman CD34 antibodies designed to attract circulating endothelial progenitor cells to rapidly establish a functional endothelial layer and promote healing stent implantation) in a cohort of consecutive patients with coronary bifurcation lesions.

METHODS AND RESULTS

Between December 2007 and July 2008, a total of 43 consecutive patients were enrolled and 47 consecutive bifurcation lesions were treated with endothelial progenitor capture cell stents. The angiographic end points binary restenosis rate inside the stent (within 5 mm of the stent edges or in the segments treated with balloon angioplasty) was 5% (2.1% in the main branch and 10.5% in the side branch). No stent thrombosis was observed. Clinical follow-up was completed in all patients at mean time of 34.5 days after percutaneous coronary interventions by clinical evaluation and 12.3 months with a telephone contact. Angina at rest was present in 3 patients (7.9%). No in-hospital, 30-days, or 12-months major adverse cardiac events (death, myocardial infarction, and repeat revascularization coronary artery bypass graft or percutaneous coronary angioplasty) were reported.

CONCLUSIONS

The use of endothelial progenitor capture cell in the setting of coronary bifurcation appears to be feasible and safe with no incidence of late stent thrombosis and a very low rate of repeated revascularization.

Immunosuppressive therapy with oral prednisone to prevent restenosis after PCI. A multicenter randomized trial

BACKGROUND

Prednisone at immunosuppressive doses after stenting has shown remarkable efficacy in reducing ischemic recurrences in nondiabetic patients with high post-procedural levels of C-reactive protein; the study aim was to compare the clinical outcome obtained in a control group of patients treated with bare metal stents versus 2 other study groups--bare metal stent plus oral prednisone or drug eluting stents--assuming similar optimal adjunctive medical treatment.

METHODS

Five tertiary Italian hospitals enrolled 375 nondiabetic patients with coronary artery disease and no contraindications to dual antiplatelet treatment or corticosteroid therapy in a randomized, controlled study performed between 2007 and 2009. Patients were allocated into 3 study groups: bare metal stents (controls), bare metal stents followed by a 40-day prednisone treatment, or drug-eluting stents. The primary endpoint was the event-free survival of cardiovascular death, myocardial infarction, and recurrence of ischemia needing repeated target vessel revascularization at 1 year as adjudicated by an independent clinical events committee.

RESULTS

One-year follow-up was obtained in all patients. Patients receiving bare metal stents alone as compared to those treated with prednisone or drug-eluting stents had lower event-free survival; the primary endpoint was 80.8% in controls compared to 88.0% in the prednisone and 88.8% in the drug-eluting stent groups, respectively (P=.04 and .006).

CONCLUSION

Compared with bare metal stents alone, prednisone treatment after bare metal stents or drug-eluting stent implantation result in a better event-free survival at 1 year.

Avoiding restenosis: is there a role for glucocorticoids in the drug-eluting stent era?

Restenosis is an important limitation of percutaneous coronary interventions (PCI). In-stent restenosis is mainly due to neointimal hyperplasia, a proliferative process modulated by inflammatory mechanisms. Numerous technical and pharmacological means have been tested to reduce restenosis rates, with frequently disappointing clinical results. Drug-eluting stents (DES) have demonstrated a high efficacy in reducing restenosis, but there are some associated problems that limit its generalized utilization. Glucocorticoids (GC), as potent anti-inflammatory agents, may exert beneficial effects on neointimal proliferation. Clinical studies with oral and intracoronary GC therapy have demonstrated reduction in restenosis rates in selected patients. Although further investigations are warranted, GC might have a potential role for restenosis prevention in selected cases.

Glucocorticoids in the prevention of restenosis after coronary angioplasty: therapeutic potential

Vessel luminal narrowing after percutaneous coronary intervention (PCI) is characterised by platelet aggregation, release of growth factors, inflammatory cell infiltration, medial smooth muscle cell (SMC) proliferation, proteoglycan deposition and extracellular matrix remodelling. It is broadly accepted that the central mechanism at the basis of the whole pathophysiological process of restenosis is inflammation, triggered by vascular injury and activated through autocrine or paracrine mediators. Glucocorticosteroids exert beneficial effects on platelet function, on SMC proliferation and on collagen synthesis as well as inflammatory cell migration and activation, thus interfering with several steps of the cascade leading to neointima formation and subsequent late lumen loss. Initial experiences with systemic administration of glucocorticoids after PCI failed to confirm the expected benefits of this treatment, probably as a result of inadequate dosage and pharmacokinetic calculations. Recently a short-term, high-dose immunosuppressive treatment scheme with oral prednisone has demonstrated remarkable clinical and angiographic results when prednisone was given orally at a dose of 1 mg/kg for 10 days, 0.5 mg/kg for 20 days and 0.25 mg/kg for 15 days. This treatment has dramatically reduced the incidence of clinical vascular events at 1 year compared with controls (relative risk 0.34; 95% CI 0.12, 0.96; p = 0.006) and reduced the incidence of angiographic restenosis below 10% in different clinical and angiographic subsets. Secondary effects of a short course of glucocorticoids are generally minor, predictable and reversible: gastric pain, water and salt retention and worsened hypertension manifest in nearly 10% of patients. The addition of diuretics and acid suppressants before discharge, and the upgrading of antihypertensive medication thereafter, if needed, are useful preventive measures to control these temporary disorders. A routine blood cell count 4 weeks after PCI is advised in patients receiving thienopyridines (clopidogrel or ticlopidine) in addition to prednisone to rule out infrequent haematological dyscrasias. Emerging evidence supports this strategy as a convenient and well tolerated alternative to more expensive and complex revascularisation procedures such as drug eluting stent (DES) implantation or cardiac surgery, provided that the treatment is reserved for carefully selected candidates, i.e. after the exclusion of those with diabetes mellitus, a recent transmural myocardial infarction, or contraindications to the administration of a short-course of high-dose glucocorticosteroids. The recent concerns regarding the long-term safety of first-generation DES and the as yet undetermined duration of dual anti-platelet treatment, further supports the need for a simple pharmacological treatment that can be applied in a large percentage of patients currently treated with PCI. Multicentre randomised studies aimed at defining the efficacy and safety of oral prednisone treatment compared with metallic stents and DES are ongoing, and will become available in upcoming years.