Elective stenting in small coronary arteries: results of the Italian prospective multicenter registry MICROSCOPE.
BACKGROUND
The role of stent implantation in small coronary arteries is still controversial. The MICROSCOPE study (Ministenting in small coronary arteries, a prospective evaluation) is a multicenter registry addressed to prospectively evaluate the immediate and mid-term clinical and angiographic results of elective stenting of lesions located in coronary arteries with an angiographic reference diameter < or = 2.75 mm.


METHODS
A total of 146 patients (160 lesions) were included in the study. The percentage of complex lesions (B2 and C lesions) was 49.3%. The clinical indications for stent implantation were: stable angina (55.0%), unstable angina (24.6%), and clinical evidence of myocardial ischemia in asymptomatic patients (20.4%); 60% of patients had multivessel disease. Stent deployment could be performed in 96.2% of lesions. The baseline reference diameter was 2.12 +/- 0.36 mm. In all cases the Ministent (Cordis, a J&J Company, Miami, FL, USA), specifically designed for small coronary arteries, was employed. The stent was pre-mounted on low profile balloons available in three different diameters (2.25, 2.50 and 2.75 mm) and three different lengths (11, 15 e 26 mm).


RESULTS
The primary endpoint of successful stent-assisted angioplasty in all study vessels without major adverse cardiac events was achieved in 95.8% of the patients. The minimal lumen diameter increased from 0.64 +/- 0.24 to 2.02 +/- 0.43 mm and the dimensions of the stenosis (expressed as a percentage of the diameter of the coronary vessel) decreased from 68.6 +/- 10.8 to 16.2 +/- 10.7% (< 30% standard deviation in all cases). After the procedure all the patients received double antiplatelet therapy for 4 weeks. Post-procedural complications were limited to 2 patients (1.3%) who had a non-Q wave myocardial infarction at 6 months of follow-up; 13 patients (11%) required target lesion revascularization. No patient died following the procedure. Angiographic control was performed in 44% of lesions. The minimal lumen diameter decreased to 1.12 +/- 0.47 mm and the percent stenosis increased to 45.9 +/- 23.2%. The incidence of binary restenosis (stenosis > or = 50%) was 41%.


CONCLUSIONS
Elective stenting of small coronary arteries with the Ministent can be safely performed and is associated with a low incidence of acute or subacute stent thrombosis. The mid-term results indicate a high rate of angiographic restenosis but a low need of target vessel revascularization. These data suggest that stenting cannot be considered the treatment of choice for unselected lesions located in coronary arteries with a small reference diameter, but represents a safe solution if unsatisfactory results are obtained with balloon angioplasty alone.
Interventional Cardiology Unit, San Raffaele Hospital, Milan.
Flavio
F
Airoldi
Carlo
C
Di Mario
Patrizia
P
Presbitero
Luigi
L
Maiello
Addolorata
A
Carcagnì
Alessandro
A
Bortone
Alberto
A
Cremonesi
Fausto
F
Castriota
Arian
A
Frasheri
Antonio
A
Rubino
Vincenzo
V
Pernice
Paolo
P
Rubartelli
Bernhard
B
Reimers
Antonio
A
Colombo
D000368:Aged; D000800:Angioplasty, Balloon; D017023:Coronary Angiography; D023903:Coronary Restenosis / Q000175:diagnosis; D003331:Coronary Vessels / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis / Q000601:surgery*; D011446:Prospective Studies; D012042:Registries; D015607:Stents; D013997:Time Factors; D016896:Treatment Outcome