Restenosis in coronary bare metal stents. Importance of time to follow-up: a comparison of coronary angiograms 6 months and 4 years after implantation.
OBJECTIVE
Angiographic late lumen loss measured 6 to 9 month after bare metal stent implantation in the coronary arteries is a validated restenosis parameter.


METHODS
We performed a second angiographic follow-up after 4 years in event free survivors from the DANSTENT trial cohort.


RESULTS
Quantitative comparison of paired coronary angiograms at 6 months and 4 years showed a reduction of late loss from 0.68+/-0.52 mm to 0.42 (+/-0.52) (mean difference 0.26 (0.17 to 0.36), p<0.0001). Minimal instent lumen diameter had increased from 2.39+/-0.62 mm to 2.64+/-0.56 mm (mean difference: -0.24 mm, 95% confidence interval: -0.34 mm to -0.14 mm, p<0.0001). Instent diameter stenosis decreased from 24.8+/-14.2% to 18.6+/-9.3% (mean difference 6.16%, 95% confidence interval: 2.82 to 9.48%, p=0.0006). This observed spontaneous decrease of instent restenosis corresponds to a 19% increase of minimal cross-sectional vessel area and a 39% reduction of the binary restenosis rate over time.


CONCLUSIONS
Instent late lumen loss in bare metal stents decreases spontaneously over time. Maturation of early hyperplastic tissue reaction after stent implantation with subsequent thinning of fibrotic tissue might explain this phenomenon.
Jørgensen
Erik
E
Cardiac Catheterisation Laboratory, Department of Cardiology, Rigshospitalet Copenhagen University Hospital, Copenhagen, Denmark. erik.joergensen@rh.regionh.dk
Helqvist
Steffen
S
Kløvgaard
Lene
L
Kastrup
Jens
J
Clemmensen
Peter
P
Holmvang
Lene
L
Engstrøm
Thomas
T
Saunamaki
Kari
K
Kelbaek
Henning
H
D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects / Q000295:instrumentation*; D017023:Coronary Angiography; D023903:Coronary Restenosis / Q000000981:diagnostic imaging / Q000209:etiology* / Q000401:mortality; D023921:Coronary Stenosis / Q000000981:diagnostic imaging / Q000401:mortality / Q000628:therapy*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D006965:Hyperplasia; D053208:Kaplan-Meier Estimate; D008297:Male; D008670:Metals; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000209:etiology; D011474:Prosthesis Design; D012075:Remission, Spontaneous; D015607:Stents; D013997:Time Factors; D016896:Treatment Outcome
D008670:Metals