Efficiency of the Guide Extension Catheter-Facilitated Tip-in Technique in the Recanalization of Coronary Chronic Total Occlusion

Figures & data

Figure 1 Depiction of guide extension catheter-facilitated tip-in technique. (A) The guide extension catheter could advance into the coronary artery to “pick up” the retrograde wire. (B) The guide extension catheter narrowed the lumen which facilitated the entry of retrograde wire into the antegrade microcatheter.

Table 1 Demographic and Clinical Characteristics

	Total (n=66)	Tip-in (n=33)	Wire Externalization (n=33)	p value
Age (years)	56 (47–66)	56 (46–65)	56 (48–67)	0.837
Male	60 (90.9)	31 (93.9)	29 (87.9)	0.392
Hypertension	46 (69.7)	20 (60.6)	26 (78.8)	0.108
Diabetes mellitus	23 (34.8)	12 (36.4)	11 (33.3)	0.796
Smoking history	32 (48.5)	16 (48.5)	16 (48.5)	1.000
OMI	18 (27.3)	10 (30.3)	8 (24.2)	0.580
Prior PCI	49 (74.2)	25 (75.8)	24 (72.7)	0.778
Prior CABG	1 (1.5)	0 (0)	1 (3.0)	1.000
Prior attempts of the target CTO	18 (27.3)	8 (24.2)	10 (30.3)	0.580
Laboratory and auxiliary examinations
Creatinine (mg/dl)	85 (75–97)	90 (73–103)	84 (75–95)	0.457
eGFR (mL/min/1.73m^2)	85 (70–97)	81 (65–100)	87 (72–96)	0.501
hs-CRP (mg/L)	0.8 (0.5–2.4)	1.6 (0.5–2.9)	0.7 (0.4–1.3)	0.120
White Blood Cell Count (x10^9/L)	6.22 (5.18–8.08)	6.04 (5.19–7.48)	6.27 (5.18–8.55)	0.202
Platelet (x10^9/L)	201 (158–253)	184 (156–232)	222 (170–264)	0.059
Hemoglobin (g/L)	140 (131–150)	138 (132–150)	140 (130–151)	0.663
NT-proBNP (pg/mL)	151.0 (69.4–350.1)	179.2 (81.2–487.0)	131.0 (64.0–205.0)	0.135
Cardiac troponin T (ng/mL)	0.012 (0.009–0.017)	0.015 (0.009–0.025)	0.011 (0.009–0.013)	0.051
Total cholesterol (mmol/L)	3.18 (2.71–3.87)	3.18 (2.86–3.58)	3.28 (2.61–3.87)	0.818
Low density lipoprotein (mmol/L)	1.38 (1.10–1.87)	1.37 (1.08–1.98)	1.46 (1.10–1.82)	0.918
Triglyceride (mmol/L)	1.60 (1.21–2.45)	1.86 (1.24–2.45)	1.48 (1.11–2.61)	0.603
High density lipoprotein (mmol/L)	0.90 (0.80–1.05)	0.89 (0.80–1.04)	0.90 (0.80–1.06)	0.969
Lp(a) (mmol/L)	28 (11–70)	33 (19–79)	23 (9–70)	0.696
Uric acid (μmol/L)	376 (326–427)	378 (333–427)	371 (325–428)	0.793
Ejection fraction (%)	62 (51–66)	62 (47–66)	64 (57–67)	0.066
Ejection fraction < 40%	6 (9.1)	5 (15.2)	1 (3.0)	0.199

Note: Data are shown as median (interquartile range) or n (%).

Abbreviations: CABG, coronary artery bypass grafting; CTO, chronic total occlusion; eGFR, estimated glomerular filtration rate; hs-CRP, high-sensitivity C-reactive protein; Lp(a), lipoprotein (a); NT-proBNP, N-terminal pro-B-type natriuretic peptide; OMI, old myocardial infarction; PCI, percutaneous coronary intervention.

Table 2 Lesion and Procedural Features

	Total (n=66)	Tip-in (n=33)	Wire Externalization (n=33)	p value
Syntax score	19.0 (12–22.5)	20.0 (13.5–23.4)	16.0 (11.0–21.5)	0.072
J-CTO score	2 (2–3)	2 (2–3)	2 (2–3)	0.533
Retrograde route				0.473
Septal	57 (86.4)	27 (81.8)	30 (90.9)
Epicardial	9 (13.6)	6 (18.2)	3 (9.1)
Rentrop classification				0.296
2	22 (33.3)	13 (39.4)	9 (27.3)
3	44 (66.7)	20 (60.6)	24 (72.7)
Werner’s classification				0.597
CC1	21 (31.8)	12 (36.4)	9 (27.3)
CC2	45 (68.2)	21 (63.6)	24 (72.7)
Target vessel
LAD	24 (36.4)	14 (42.4)	10 (30.3)	0.306
LCX	1 (1.5)	1 (3.0)	0 (0)	1.000
RCA	41 (62.1)	18 (54.6)	23 (69.7)	0.205
Antegrade guide catheter size				0.282
6F	9 (13.6)	3 (9.1)	6 (18.2.)
7F	57 (86.4)	30 (90.9)	27 (81.8)
Retrograde guide catheter size				0.186
6F	45 (68.2)	25 (75.8)	20 (60.6)
7F	21 (31.8)	8 (24.2)	13 (39.4)
Antegrade microcatheter
None	5 (7.6)	0 (0)	5 (15.2)	0.053
Corsair (Asahi)	20 (30.3)	5 (15.2)	15 (45.5)	0.007
Instantpass (APT)	39 (59.1)	28 (84.8)	11 (33.3)	<0.001
KDLC (Kaneka)	2 (3.0)	0 (0)	2 (6.1)	0.492
Retrograde microcatheter
Corsair (Asahi)	36 (54.5)	18 (54.5)	18 (54.5)	1.000
Instantpass (APT)	27 (40.9)	15 (45.5)	12 (36.4)	0.453
Finecross (Terumo)	2 (3.0)	0 (0)	2 (6.1)	0.492
Retrograde extension catheter				0.641
Guidezilla (6F, Boston Scientific)	5 (7.5)	2 (6.1)	3 (9.1)
Expressman (5F, APT)	61 (92.5)	31 (93.9)	30 (90.9)
Retrograde crossing technique
Wire escalation	25 (37.8)	15 (51.6)	10 (24.2)	0.205
Reverse CART	39 (59.1)	16 (42.4)	23 (75.8)	0.080
Parallel wire	2 (3.0)	2 (6.1)	0 (0)	0.490
PTCA without stenting	6 (9.1)	2 (6.1)	4 (12.1)	0.669
Stent length (mm)	67.8±35.1	62.0±33.2	73.7±36.5	0.052
Contrast volume (mL)	310 (240–410)	315 (235–405)	310 (240–410)	0.949
Manipulation time^# (second)	493 (376–720)	389 (272–478)	706 (560–914)	<0.001
Operation time (minute)	150 (108–190)	141 (106–170)	159 (124–201)	0.079
Radiation dose (mGy)	2706 (1879–3605)	2363 (1701–3873)	2771 (2192–3605)	0.223

Notes: Data are shown as median (interquartile range), mean ± standard deviations or n (%). ^#The time interval from the first retrograde wire entering the antegrade guide to the first antegrade balloon inflation in the occlusion was calculated.

Abbreviations: CART, controlled antegrade and retrograde subintimal tracking; LAD, left anterior descending artery; LCX, left circumflex artery; PTCA, percutaneous coronary angioplasty; RCA, right coronary artery.