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MI, myocardial infarction; CABG, coronary artery bypass graft; TLR, target lesion revascularization; NR, not reported ap < 0.05

bdeath, MI, target vessel revascularization.

MI, myocardial infarction; CABG, coronary artery bypass graft; TLR, target lesion revascularization; NR, not reported ap < 0.05

bdeath, MI, target vessel revascularization.

device used (22). The high rate of restenosis associated with DCA in these trials was attributed to the 25% residual stenoses that were not treated with routine postdilation following DCA. Thus, the goal of more recent trials has been to perform "optimal" atherectomy, in which case the postprocedure lumen diameter is made as large as possible and the residual stenosis minimized (<10%). Two atherectomy trials, the Balloon vs Optimal Atherectomy Trial (BOAT) (23) and the Optimal Atherectomy Restenosis Study (OARS) (24), tested DCA followed by adjunctive low-pressure balloon dilation. High procedural success rates 97-98% and low rates of major in-hospital complications (death, Q wave MI, CABG surgery) (2.1-3.5%) were achieved in DCA patients with adjunctive PTCA (23,24). In addition, final diameter stenosis was reduced to less than 10% in both trials after adjunctive PTCA. The BOAT study also confirmed a 21% relative reduction in the 6-mo angiographic restenosis rate for DCA with adjunctive PTCA over PTCA alone (31.4 vs 39.8%, p = 0.01), thereby confirming that "bigger is better" (23). Because an increased postprocedural lumen diameter is such a significant correlate of reduced restenosis rates, conventional PTCA has become a common adjunct to successful but suboptimal (>10% residual stenosis) DCA procedures when the risk of additional atherectomy cuts seem to be substantial.

DCA has been associated with an increased risk of significant CK-MB leak. However, it is not clear that low levels of myocardial necrosis portend poorer prognoses in this subset of patients (25). Moreover, the use of adjunctive abciximab (a Gp IIb/IIIa antagonist) can reduce the incidence of periprocedural non-Q wave MI by over 50% (26). DCA provides a unique opportunity to essentially "biopsy" the lesion. This has demonstrated that the risk of restenosis following DCA may be influenced by other factors, such as prior cytomegalovirus infection (27). At present, DCA is indicated as an alternative to PTCA in de novo lesions in vessels >3 mm, bifurcation lesions, ostial lesions, and for the treatment of in-stent restenosis (ISR).

Rotational Atherectomy

Rotational atherectomy (RA) is a treatment technique that utilizes a diamond-studded burr spinning at speeds from 140,000-200,000 rpm to ablate atherosclerotic tissue in coronary arteries. This technique operates under the principle of differential cutting, whereby the less compliant diseased calcified tissue is preferentially abraded in preference to the more compliant nondiseased vascular tissue. The abrasive nature of lesion debulking leads to distal embolization of plaque microparticles, which are approx 2-5 im in size (i.e., smaller than a red blood cell) and generally pass through microcirculation, and are eventually cleared by the reticuloendothelial system. Occasionally, when these microparticles are liberated to the distal microvasculature in large concentrations, they can cause myocardial ischemia or even infarction. Indeed, the no-reflow phenomenon is more frequent in RA (7.7%) than PTCA procedures (0.3%) (28). As a result of this risk, RA of the right coronary artery is typically done with a temporary pacing wire in place, as A-V block and bradycardia are significant risks of right coronary artery manipulation. To combat the effects of no-reflow during RA procedures, intracoronary vasodilators such as nitrates and calcium channel blockers are routinely administered, therefore adequate vol status must be maintained. Recent evidence demonstrates that slower speeds (29) and the use of adjunctive Gp Ilb/IIIa antagonists (30) decrease platelet activation and aggregation and decreases the risk of no-reflow.

Intravascular ultrasound (IVUS) studies of rotational atherectomy have shown that improvement in lumen diameter is primarily due to selective removal of calcified plaque, with minimal stretching of the vessel (31). Due to the small diameter of available burrs, however, low-pressure adjunctive balloon PTCA is required in most rotational atherectomy cases (32).

In the ERBAC trial (14), rotational atherectomy was compared to conventional PTCA in complex lesions. Rotational atherectomy had a higher procedural success rate (91 vs 80%, p < 0.001), a lower residual percent diameter stenosis (31 vs 36%, p < 0.05), a similar restenosis rate (62 vs 54%, p = NS), but a higher repeat revascularization rate at 6 mo (46 vs 35%, p = 0.04) compared to conventional PTCA. A report from a 709 patient multicenter rotational atherectomy registry showed a high rate of procedural success (95%) and low rates of death (0.8%), Q wave MI (0.9%), non-Q wave MI (3.8%), and emergency CABG surgery (1.7%) (33). There was a somewhat lower 6-mo angiographic restenosis rate (38%) in 527 patients available for repeat angiography in this registry compared with that reported in the ERBAC study (33).

A pooled analysis of 5250 patients undergoing rotational atherectomy shows a 93.7% (4920 out of 5250) rate of procedural success, a 0.6% (32 out of 5035) mortality rate, a 1.6% (83 out of 5035) rate of CABG surgery, a 1.4% (72 out of 5035) rate of Q wave MI, and 6.8% (276 out of 4033) rate of non-Q wave MI (32-42) (Table 2). The rate of restenosis was 42% (697 out of 1657) at follow-up, a rate similar to that of conventional PTCA. Although there are observational data suggesting clinical benefits from RA in certain lesion subsets, there have been no multicenter randomized trials demonstrating its superiority over conventional PTCA.

Research into optimal rotational atherectomy strategies is ongoing. The Study to Determine Rotablator System and Transluminal Angioplasty Strategy (STRATAS) trial (43) was performed to evaluate an "aggressive" strategy (n = 249) with burr/artery ratio >0.70 alone or with low-pressure adjunctive balloon <1 atmosphere vs the "routine"

Table 2

Pooled Data from Early Studies of Rotational Atherectomy

Table 2

Pooled Data from Early Studies of Rotational Atherectomy

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