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Procedural success is defined as a residual stenosis <50% with no incidence of death, Q wave MI, or emergency CABG.

All complications (mortality, CABG surgery, Q wave MI, non-Q wave MI) are in-hospital.

Procedural success is defined as a residual stenosis <50% with no incidence of death, Q wave MI, or emergency CABG.

All complications (mortality, CABG surgery, Q wave MI, non-Q wave MI) are in-hospital.

strategy (n = 248) with burr/artery ratio < or = to 0.70 with balloon inflation >4 atmosphere. Initial and 6-mo follow-up clinical and angiographic results were similar, but multivariate analysis showed that left anterior descending location (odds ratio 1.67, p = 0,02) and operator-reported excessive speed decreases of >5000 rpm (odds ratio 1.74, p = 0.01) were independent predictors of restenosis. Similarly, the Coronary Angioplasty versus Rotablator Atherectomy Trial (CARAT) (44) was performed to evaluate whether a lesion-debulking strategy, accomplished with large burr/artery ratios (>0.7) conferred any advantage over a lesion-modifying strategy with smaller burr/artery ratios (<0.7). Angiographic success rates were similar, but larger burr/artery ratios were associated with more frequent serious angiographic complications when compared to smaller burr/artery ratios (12.7% vs 5.1%, p = 0.05).

Rotational atherectomy can be an effective technique in those lesions with angio-graphic characteristics predictive of low success rates following conventional PTCA. These include calcified lesions, ostial lesions, in-stent restenosis, and possibly total occlusions.

Transluminal Extraction Catheter

Transluminal extraction catheter (TEC) atherectomy enlarges the arterial lumen by cutting, aspirating, and removing thrombus, plaque, and other obstructing debris. In contrast to the discrete tissue fragments retrieved by DCA, TEC results in a slurry of blood and debris. The difficulty associated with treating highly thrombotic native coro nary or saphenous vein graft lesions, distal thromboembolism (DTE), and the "no reflow" phenomenon with conventional PTCA prompted the development of the TEC device and the Angiojet rheolytic thrombectomy catheter. The NACI registry has reported on the largest cohort of patients treated with this device. These results show a low device success rate (48%), but an acceptable procedural success rate with adjunctive PTCA (87%) (45). As a result of the small size (<2.5 mm) of the TEC cutters and a limited ability to aspirate, this procedure is associated with inadequate lumen enlargement when used as a "stand-alone" device (45). Follow-up reports from NACI have demonstrated that the multivariate predictors of DTE with TEC are noncardiac disease, stand-alone TEC, thrombus, and larger vessel size (46). The rate of DTE is 8.3% in this registry of high-risk patients, and it carries a high in-hospital mortality rate (18.5%).

Rheolytic Therapy

The Angiojet rheolytic thrombectomy system is a novel treatment technique that employs the Bernoulli principle in vacuum-extracting thrombus. The catheter has a stainless-steel tip that houses three jets that propel saline proximally into an effluent port system. The saline rushes past a circumferential opening (0.5 mm in width) in the catheter tip creating a relative vacuum that aspirates blood and thrombus adjacent to the tip into the effluent chamber. As thrombus enters the catheter, it is mechanically broken down by the action of the saline and flushed out of the body. Typically, the catheter is passed multiple times, until no further obstructing thrombus is seen, or no further improvements are made with additional passes.

Pilot studies of the Angiojet were encouraging, with significant reductions in thrombus burden, and high degrees of procedural and clinical success, notably in a relatively high-risk patient population with acute ischemic syndromes (47). Subsequent randomized comparative trials have demonstrated its relative safety and efficacy in comparison to the intracoronary administration of the thrombolytic medications urokinase (48). A recent trial of patients with acute MI demonstrated that the angiographic success was 93.8% with the use of adjunctive measures in 95% of cases (67% stent, 26% balloon alone, 1% RA, 1% DCA) (49). Procedural success was 87.5%, with an in-hospital mortality of 7.1%. Of note, bradycardia occurred in 52% of patients, requiring atropine, temporary pacemaker, or both in up to 31% of cases. The results of this trial are remarkable in light of the nonexclusion of patients with cardiogenic shock. Sixteen percent of patients met clinical criteria for shock at time of enrollment, a factor that has portended a very poor outcome in previous trials of acute MI (50). Thirty-day outcomes were excellent: no further MIs or deaths occurred, and freedom from major adverse cardiac event rate was 92.9%, reflecting the initial mortality of 7.1%.

The present indications for rheolytic thrombectomy therapy are the presence of moderate or severe thrombus in native vessels or saphenous vein grafts larger than 2.0 mm prior to the performance of definitive therapy with stent, PTCA, or other PCI for myocardial ischemia.

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