Evaluation of the long-term functional outcome assessed by myocardial perfusion scintigraphy following excimer laser angioplasty compared to balloon angioplasty in longer coronary lesions

Abstract

Objectives: Evaluation of the long-term functional outcome assessed by exercise myocardial perfusion imaging following excimer laser angioplasty compared to balloon angioplasty in coronary lesions > 10 mm in length.

Background: Previous randomized studies evaluating the effect of coronary interventions mainly focused on the long-term clinical and angiographic outcome. The functional outcome, assessed by myocardial perfusion scintigraphy, has not been evaluated in a randomized setting.

Methods: A total of 308 patients with stable angina and a longer coronary lesion (> 10 mm) were randomized to excimer laser angioplasty or balloon angioplasty. A 99mTechnetium-2-methoxy isobutyl isonitrile (MIBI) single-photon emission computed tomography (SPECT) study was performed in 139 patients before the initial angioplasty procedure and at 6 months follow-up (73 patients in the laser group versus 66 patients in the balloon group, respectively). Exercise tolerance at follow-up was compared to baseline values by means of exercise duration and double product at peak exercise. Myocardial perfusion of the randomized vascular bed was assessed semi-quantitatively on the MIBI SPECT images. The reversible defects were graded as mild, moderate or severe. Myocardial perfusion at follow-up was expressed as a percentage reduction in incidence and grading of the reversible defects compared to baseline values.

Results: Forty-four (61%) patients assigned to laser angioplasty were asymptomatic at 6 months follow-up compared to 34 (52%) patients assigned to balloon angioplasty (p = NS). Improvement in exercise duration and double product were 0.7 +/- 2.1 min and 4.3 +/- 6.2 min/mmHg/l,000, respectively, in the laser group, versus 0.3 +/- 2.5 min and 3.1 +/- 5.5 min/mmHg/1,000, respectively, in the balloon group (both p = NS). The percentage reduction of reversible defects was 23% in patients assigned to laser angioplasty vs. 29% in patients assigned to balloon angioplasty (Relative risk [RR]: 0.79, 95% confidence interval [CI]: 0.40-1.57; p = 0.50). The mild, moderate and severe reversible defects improved in 44.4, 63.6 and 66.6%, respectively, in the laser angioplasty group vs. 66.6, 53.8 and 90%, respectively, in the balloon angioplasty group. None of the comparisons were significantly different.

Conclusion: Excimer laser angioplasty compared to balloon angioplasty in coronary lesions > 10 mm in length yields a similar long-term functional outcome assessed by anginal status, exercise tolerance and myocardial perfusion.