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Although distal coronary flow velocity reserve (CFVR) measured by intracoronary Doppler guide wires 1-8 improves significantly after successful balloon angioplasty, it frequently remains subnormal. 2 9 10 This suboptimal increase of distal CFVR after successful angioplasty has been ascribed to ischaemic stunning of the myocardial microvasculature, 11 to a residual luminal narrowing not appreciated on angiography, 12 or both. Coronary stenting results in a larger lumen gain than after balloon angioplasty and has been shown to result in a greater increase in distal CFVR. 12-16
However, even after successful stenting CFVR may remain suboptimal. 17 This can be caused by impaired microvascular vasodilatation but also by unsatisfactory lumen enlargement after stent placement. Different stent types probably do not have the same properties in the coronary artery. Coil stents are possibly not as effective as tubular stents in restoring the conduit function of the epicardial arteries. Coil stents have a more open design that promotes plaque prolapse and do not always provide a uniform radial expansion of the vessel lumen. This may result in a lower lumen increase and therefore a lower CFVR increase than when a tubular stent is used. In this study we compared the effect of tubular and coil stents on epicardial flow conductance and on distal CFVR.
Methods
PATIENT POPULATION
The study population comprised 31 patients with stable angina undergoing elective coronary angioplasty and stenting of a non-occlusive major stenosis (diameter stenosis > 50%) in a native coronary artery (table 1 ). All patients had single vessel disease with normal left ventricular function; stenting was performed because of a suboptimal angioplasty result (residual diameter stenosis > 35%) or threatened closure (residual diameter stenosis > 50% with dissection type C or D). Patients with a myocardial infarction in the perfusion territory of the treated artery, valve disease, congestive heart failure, or notable left ventricular hypertrophy were excluded. Angiographic exclusions included presence of collateral circulation, bypass graft to the target vessel, ostial narrowing inducing wedging of the catheter, distal lesions with small perfusion bed, and lesions not amenable to be crossed by the Doppler coronary guide wire.
Table 1 Patient characteristics and angiographic findings
Values are numbers unless otherwise indicated.
LAD, left anterior descending artery; RCA, right coronary artery; CX, circumflex artery, ACC, American...