Coronary blood flow velocities during rotational atherectomy

This study was designed to evaluate the alterations in doppler derived coronary blood flow velocities and flow reserve following rotational ablation. Changes in doppler derived coronary blood flow velocity variables have been valuable in assessing the physiological outcome following coronary balloon angioplasty. Rotational ablation's mechanism of plaque removal could alter distal vascular bed characteristics, and, as a result, intracoronary blood flow velocities and the coronary flow reserve. A 12-MHz doppler guidewire recorded intracoronary phasic velocities and coronary flow reserve (as assessed by the hyperemic response to adenosine [12-18 mcg intracoronary]) in 28 patients, before and after rotational ablation of 30 lesions. Adjunctive balloon angioplasty was performed in 27 of 28 patients (96%). Rotational ablation and adjunctive balloon angioplasty successfully reduced the lesion diameter (87 +/- 9% to 14 +/- 11%; P < 0.001). A significant increase in the mean distal average peak velocity (25 +/- 13 cm/sec, before; 47 +/- 22 cm/sec, after; P < 0.001), and decrease in the proximal to distal average peak velocity ratio, (2.1 +/- 1.3; to 1.2 +/- 0.4; P = 0.002) was recorded. The mean distal diastolic to systolic velocity ratio (before, 1.4 +/- 0.7; after, 1.6 +/- 0.8; P = 0.44) and the coronary flow reserve (before, 1.6 +/- 0.6; after, 1.5 +/- 0.5; P = 0.34) did not increase despite increases in distal velocities, following successful intervention. Doppler derived distal coronary blood flow velocities increased following rotational ablation and adjunctive balloon angioplasty, with resolution of transstenotic velocity gradient. Changes in distal phasic velocity pattern and coronary flow reserve, immediately after the intervention, were not useful in the assessment of the functional outcome and may be related to abnormalities in distal vascular bed vasoreactivity produced by rotational ablation.