Balloon lesions

Not all researchers use the same definition of osteolysis in their radiographic analyses, complicating the comparison of results between smdies. Some researchers identily radiolucencies around the margin of an implant as a linear lytic defect [52], whereas in other smdies, only a focal lesion or cyst is classified as osteolysis [46]. Of greatest clinical concern are unstable or expansile lesions (so-called balloon lesions ) that grow over time and lead to aseptic loosening of a prosthetic component. 

Laser ablation systems hold considerable promise if restenosis (reblocking of the arteries) rates are reduced. The rate as of 1995 is 30%, typically within six months. Mechanical or atherectomy devices to cut, shave, or pulverize plaque have been tested extensively in coronary arteries. Some of these have also been approved for peripheral use. The future of angioplasty, beyond the tremendous success of conventional balloon catheters, depends on approaches that can reduce restenosis rates. For example, if appHcation of a dmg to the lesion site turns out to be the solution to restenosis, balloon catheters would be used for both dilating the vessel and deUvering the dmg. An understanding of what happens to the arterial walls, at the cellular level, when these walls are subjected to the various types of angioplasty may need to come first. 

Betriu A, Masotti M, Serra A, et al. Randomized comparison of coronary stent implantation and balloon angioplasty in the treatment of de novo coronary artery lesions (START) a four-year follow-up. J Am Coll Cardiol 1999 34 1498-1506. 

Recent evidence suggests that atherosclerosis is a chronic inflammatory process. The recruitment of mononuclear leukocytes and formation of intimal macrophage-rich lesions at specific sites of the arterial tree are key events in atherogenesis. Alterations of chemotactic and adhesive properties of the endothelium play an important role in this process [82]. Quercetin has been reported to inhibit the expression in glomerular cells of monocyte chemoattractant protein-1 (MCP-1) [83] a potent chemoattractant for circulating monocytes. Red wine reduced MCP-1 mRNA and protein expression in abdominal aorta of cholesterol fed rabbits after balloon injury and this effect was associated with a reduced neointimal hyperplasia [84]. The antioxidant-mediated inhibition of nuclear factor k B (NFkB) and the subsequent non selective reduction of cytokine transcription have been suggested to be responsible for these effects [83]. Additionally, quercetin downregulated both phorbol 12-myristate 13-acetate (PMA)- and tumour necrosis factor-a (TNFa)-induced intercellular adhesion molecule-1 (ICAM-1) expression in human endothelial cells [86]. 

Heparin-coated Palmaz-Schatz, Wiktor, Jostent, BX Velocity, and beStent have been investigated in clinical studies. All studies showed that heparin-coated stents are safe, even in high-risk lesions. When compared with balloon angioplasty, heparin-coated stents could significantly reduce the rate of subacute stent thrombosis and the late restenosis. However, no significant difference of restenosis was observed between the heparin-coated stent and the bare stent control. 

Serruys PW, Degertekin M, Tanabe K, etal. Intravascular ultrasound findings in the multicenter, randomized, double-blind RAVEL (RAndomized study with the sirolimus-eluting VEIocrty balloon-expandable stent in the treatment of patients with de novo native coronary artery Lesions) trial. Circulation 2002 ... 

The pivotal Sirolimus-coated BX VELOCITY Balloon-Expandable Stent in Treatment of Patients with De Novo Coronary Artery Lesions (SIRIUS) study of the CYPHER SES demonstrated a low rate of reintervention compared with... 

In 1997, Condado et al. was the first to investigate the effectiveness of ICB after PTCA in human coronary arteries. Twenty-one patients who underwent PTCA for unstable angina received ICB (gamma radiation) for prevention of restenosis, Immediate and six-month follow-up revealed improved freedom from major adverse cardiac event (MACE) defined as death, myocardial infarction or target lesion revascularization compared with several previously completed balloon angioplasty trials (20), More importantly, this trial demonstrated that ICB was a feasible technique for the prevention of restenosis without any unexpected acute complications in humans. 

Since these original studies, there have been numerous clinical randomized trials and prospective registries detailing the efficacy of ICB as an adjunctive therapy for de novo native coronary or sapheneous vein graft lesions treated with balloon angioplasty and/or stent implantation (Table I), The... 

Serruys PW, Foley DR Suttorp M-J, et al. A randomized comparison of the value of additional stenting after optimal balloon angioplasty for long coronary lesions. J Am Coll Cardiol 2002 39 393-399. 

Moussa I, Leon MB, Bairn DS, et al. Impact of sirolimus-eluting stents on outcome in diabetic patients a SIRIUS (SIRollmUS-coated Bx Velocity balloon-expandable stent in the treatment of patients with de novo coronary artery lesions) substudy. Circulation 2004 109 2273-2278. 

This is a critical step and requires careful attention since it is at this stage that embolic events are most likely to develop. The risk of embolization is minimized by conservative sizing of the balloon (5 mm) and by performing a single inflation. The balloon should be deflated slowly. Mild residual stenoses (<20%) or persistence of an ulcer at the lesion site should be accepted, since aggressive stent dilatation can produce cerbral embolization. 

Arteriosclerotic lesions in rats can result from chronic graft rejection and from balloon injury following angioplasty but are suppressed by CO [18]. 

The indications for PTCA have been provided by the ACC/AHA and now span single- or multivessel disease as weU as asymp-tomatic and symptomatic patients (see Table 15-7). PTCA generally is not useful if only a small area of viable myocardium is at risk, when ischemia cannot be demonstrated, with borderline (<50%) stenosis or with lesions that are difficult to dilate, or in patients who are at high risk for morbidity or mortality or both (e.g., left main or equivalent disease or three-vessel disease). PTCA alone or in conjunction or sequentially with thrombolysis for acute Ml is discussed in Chap. 16. Stent placement accompanies balloon angioplasty in about 80% of cases in the United States. The current recommendations for PCI are provided in Table 15-7 based on class of angina. 

FIGURE 3.2 Bifurcation lesion algorithm for coronary intervention. (DES, drug-eluting stent SB, side branch MB, main branch SKS, simultaneous kissing stents KB, kissing balloons.)... 

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