Restenosis in coronary bare metal stents. Importance of time to follow-up: A comparison of coronary angiograms 6 months and 4 years after implantation

Figures & data

Table I.  Baseline characteristics

	All DANSTENT patients	6 months and 4 years angio
	n=424	No n=64	Yes n=44	p
Demographics
Mean (SD) age, years	60.3 (±10.0)	62.6(±10.1)	56.8(±9.0)	0.002
Men,%	70.4	64.0	79.5	0.09
Risk factors
Diabetes mellitus,%	11.1	9.3	13.6	0.22
Smokers, previous or current,%	71.3	64.0	81.8	0.13
History
Myocardial infarction,%	51.9	48.4	56.8	0.23
Unstable angina,%	18.5	15.6	20.4	0.57
Angina class ≥CCS 2	93.6	84.3	81.2	0.60
Study Lesion Location
LAD,%	44.4	43.7	45.4
LCX,%	20.3	20.3	20.4	| 0.97
RCA,%	35.2	35.9	34.0
Number of diseased vessels,%
1	66.7	62.5	72.7
2	29.6	31.2	27.2	| 0.19
3	3.7	6.2	0.0
Lesion morphology
Type A,%	16.7	14.6	20.4
Type B,%	75.0	76.5	72.7	| 0.63
Type C,%	8.3	9.3	6.8
Length, mm	12.0 (±4.5)	12.3 (±4.6)	11.6 (±4.2)	0.47
Stent type/technique
Palmaz-Schatz stent,%	49.5	59.3	50.0	| 0.43
Nir stent,%	44.5	40.6	50.0
Stent balloon pressure, atm	15.2 (±3.0)	15.2(±3.2)	15.0(±2.6)	0.75

CCS class 1, 2 or 3, refers to severity of angina according to the Canadian Cardiovascular Society angina classification.

LAD=Left anterior descending artery, LCX=Left circumflex artery, RCA=Right coronary artery. Lesion morphology is classified according to the American College of Cardiology/American Heart Association coronary lesion morphology classification.

Figure 1.  Kaplan Meier distribution of major adverse events Any event=the composite of death (cardiac and non-cardiac), coronary artery bypass surgery, any percutaneous coronary intervention (target segment and non-target segment) and myocardial infarction.

Table II.  Number of major adverse events in patients with and without paired 6 months and 4 years angiograms

	Paired Angiograms		Total
Major adverse events	no	yes
None	29	31	60
Target vessel PCI	12	0	12
CABG	6	0	6
Myocardial infarction	2	4	6
Cardiac/sudden death	3	0	3
Any other death	7	0	7
Non-target vessel PCI	5	9	14
Total	64	44	108

Table III.  Angiographic baseline data in patients with and without paired 6 months and 4 years angiogram

	Paired 6 month and 4 years angiograms
	No	Yes	Difference (95% CI)	p
Before procedure	n=61	n=44
Reference vessel diameter, mm	2.98 (±0.54)	3.13 (±0.62)	−0.15 (−0.38 to 0.07)	0.18
Minimal lumen diameter, mm	1.01 (±0.46)	1.01 (±0.50)	0.00 (−0.18 to 0.19)	0.98
Diameter stenosis, %	64.9 (±16.3)	67.7 (±14.4)	−2.8 (−8.9 to 3.2)	0.36
After procedure	n=61	n=44
Reference vessel diameter, mm	3.22 (±0.47)	3.33 (±0.61)	−0.10 (−0.32 to 0.10)	0.31
Minimal lumen diameter, mm	2.83 (±0.43)	3.07 (±0.55)	−2.3 (−0.43 to-0.04)	0.01
Diameter stenosis, %	11.6 (±9.6)	7.3 (±9.0)	−0.2 (5.6 to 8.0)	0.02
At 6 months follow-up	n=49	n=44
Reference vessel diameter, mm	3.08 (±0.55)	3.18 (±0.56)	0.11 (−0.32 to 0.13)	0.41
Minimal lumen diameter, mm	1.90 (±0.79)	2.39 (±0.62)	0.14 (−0.78 to 0.11)	0.01
Diameter stenosis, %	37.9 (±23.9)	24.8 (±14.3)	13.2 (5.0 to 21.4)	0.002

Figures are means (± standard deviation), CI=Confidence interval

Table IV.  Angiographic results in patients with 4 years follow-up

	Time to follow up
	6 months	4 years	Difference (95% CI)	p
Reference Vessel Diameter, mm	3.18 (±0.56)	3.23 (±0.55)	−0.05 (−0.13 to 0.04)	0.25
Minimal Lumen Diameter, mm	2.39 (±0.62)	2.64 (±0.56)	−0.24 (−0.34 to −0.14)	<0.0001
Diameter Stenosis,%	24.8 (±14.3)	18.6 (±9.16)	6.15 (2.82 to 9.48)	0.0006
Late Loss, mm	0.68 (±0.52)	0.42 (±0.52)	0.26 (0.17 to 0.36)	<0.0001
Net Gain, mm	1.38 (±0.78)	1.62 (±0.72)	−0.24 (−0.34 to −0.14)	<0.0001
Loss Index	0.35 (±0.29)	0.20 (±0.27)	0.15 (0.10 to 0.20)	<0.0001
Minimal Cross-Sectional Area, mm^2	4.80 (±2.35)	5.71 (±2.34)	−0.92 (−1.30 to −0.53)	<0.0001

Figures are means (± standard deviation). CI=Confidence interval. Late Loss=Minimal lumen diameter post procedure minus minimal lumen diameter at follow-up. Net gain=Acute gain minus late loss. Loss index=Late loss divided by acute gain. Minimal cross-sectional area=(Minimal lumen diameter/2) ²×π

Figure 2.  The expected binary restenosis rate The curve to the right is the cumulative distribution of diameter stenosis in all patients in the DANSTENT study 10. In the curve to the left, the expected 4 years cumulative distribution of diameter stenosis, is calculated by subtracting the expected late restenosis regression of 6.15% for each patient. The binary restenosis rates (% of patients with ≥50% diameter stenosis) at 6 months follow-up and at 4 years follow-up are indicated with the arrows

Stone GW, Ellis SG, Cannon L, Mann JT, Greenberg JD, Spriggs D, et al. Comparison of a polymer-based paclitaxel-eluting stent with a bare metal stent in patients with complex coronary artery disease: A randomized controlled trial. JAMA. 2005; 294: 1215–23

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