TARGET LESION CALCIFICATION IN CORONARY-ARTERY DISEASE - AN INTRAVASCULAR ULTRASOUND STUDY

Objectives. The purpose of this study was to evaluate the frequency, amount and distribution of target lesion calcification in patients undergoing transcatheter therapy for symptomatic coronary artery disease. Background. Coronary artery target lesion calcification may be an important determinant of response to transcatheter therapy: balloon angioplasty causes dissections in calcified lesions, directional atherectomy cuts calcium poorly, rotational atherectomy causes preferential ablation of calcium and laser irradiation effect may vary. Intravascular ultrasound imaging is a highly sensitive technique for detection of plaque calcification in vivo. Methods. We performed intravascular ultrasound imaging before or after, or both, various transcatheter therapies in 110 patients. These 84 men and 26 women had a mean age of 60 years and a duration of angina of 22 +/- 34 months. Forty-nine patients had one-vessel, 29 had two-vessel, 25 had three-vessel and 7 had left main coronary disease. Vessels treated and imaged were the left main (n = 7), left anterior descending (n = 47), left circumflex (n = 18) and right (n = 38) coronary arteries. Results. Eighty-four patients (76%) had target lesion calcification; 29 patients had one-quadrant, 25 had two-quadrant, 17 had three-quadrant and 13 had four-quadrant calcification. The calcification was superficial in 42 patients, deep in 13 and both superficial and deep in 31. The axial length of calcium could be measured in 29 patients; it was less-than-or-equal-to 5 mm in 11 and greater-than-or-equal-to 6 mm in 18. Fluoroscopy detected calcification in 50 patients (48%, p < 0.001 vs. detection by ultrasound); this proportion increased to 74% in patients with calcification of two or more quadrants and to 86% in patients with calcification greater-than-or-equal-to 6 min in length of two or more quadrants. Calcification was more common in patients who smoked and tended to be more common in patients with multivessel disease or previous coronary artery bypass graft surgery. Conclusions. We conclude that target lesion calcification occurs in 75% of patients with symptomatic coronary artery disease requiring angioplasty. Target lesion calcification is best detected, localized and quantified by intravascular ultrasound. These observations may be important in selecting devices for transcatheter therapy.