Patient Characteristics
From 2017 to 2019, 615 patients were selected, including 165 patients treated with NT technology and 450 patients with conventional technology. Finally, a total of 505 patients were included in the study. As shown in Figure 1, a total of 150 patients were enrolled in the NT group, and 355 patients were enrolled in the CON group. The baseline data of the two groups were compared. There were differences in sex, body mass index (BMI), smoking, hypertension, previous percutaneous coronary intervention (PCI) history and New York Heart Association (NYHA) classification between the two groups. After applying propensity score matching (1:1 matching), 148 patients were included in each group. There was no significant difference in the baseline data of the matched groups, as shown in Table 1. We promised that our experiment for involving humans was in accordance to guidelines of the Declaration of Helsinki. This study was approved by the Ethics Committee of Beijing Anzhen Hospital (Approval Numbers: 2018036X). Informed consent was obtained from all individual participants included in the study.
Table 1
Preoperative Characteristics and Risk Factors of Study Patients
Variables | All study patients | Propensity-matched patients |
---|
Group NT (n = 150) | Group CON (n = 350) | P value | Group NT (n = 148) | Group CON (n = 148) | P value |
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Age (years), mean ± SD | 59.8 ± 9.0 | 60.5 ± 9.0 | 0.423 | 59.9 ± 8.9 | 60.4 ± 8.6 | 0.605 |
Female, n (%) | 13(8.7) | 76(21.4) | 0.001 | 13(8.8) | 16(10.8) | 0.557 |
BMI>25(kg/m2), n (%) | 94(62.7) | 181(51.0) | 0.016 | 92(62.2) | 90(60.8) | 0.811 |
Smoking, n (%) | 73(48.7) | 137(38.6) | 0.036 | 72(48.6) | 83(56.1) | 0.20 |
Hypertension, n (%) | 100(66.7) | 176(49.6) | < 0.001 | 98(66.2) | 100(67.6) | 0.805 |
Diabetes mellitus, n (%) | 63(42.0) | 121(34.1) | 0.091 | 62(41.9) | 70(47.3) | 0.350 |
Previous MI, n (%) | 57(38.0) | 128(36.1) | 0.679 | 57(38.5) | 60(40.5) | 0.721 |
Previous PCI, n (%) | 23(15.3) | 32(9.0) | 0.037 | 22(14.9) | 19(12.8) | 0.614 |
Stroke, n (%) | 16(10.7) | 30(8.5) | 0.429 | 16(10.8) | 16(10.8) | 1.000 |
NYHA, n (%) | | | < 0.001 | | | 0.485 |
I | 2(1.5) | 3(0.8) | | 2(1.4) | 2(1.4) | |
II | 109(72.7) | 161(45.4) | | 107(72.3) | 101(68.2) | |
III | 36(24.0) | 182(51.3) | | 36(24.3) | 43(29.1) | |
IV | 3(2.0) | 9(2.5) | | 3(2.0) | 2(1.4) | |
LVEF(%)<45%, n (%) | 6(4.0) | 20(5.6) | 0.448 | 6(4.1) | 11(7.4) | 0.212 |
Left main disease, n (%) | 51(34.0) | 102(28.7) | 0.239 | 50(33.8) | 49(33.1) | 0.902 |
NT: No-touch saphenous vein graft harvesting; CON: Conventional saphenous vein graft harvesting; BMI: Body mass index; MI: Myocardial infarction;PCI: Percutaneous coronary intervention; NYHA: New York Heart Association; LVEF: Left ventricular ejection fraction. |
Operative Strategies
NT group
When harvesting the great saphenous vein, approximately 0.5cm of tissue on both sides of the main vein was preserved without destroying the adventitia. The visible branches of the main vein were ligated with ligation wire, and the left and right sides were clamped with silver clips. After the vein was obtained, it was stored in a mixture of heparin and papaverine without manual dilation. After anastomosing with the proximal end of the ascending aorta, the blood pressure of the ascending aorta was used to check whether there was branch leakage in the main vein. If so, silver clips were used for clamping. After all anastomoses were completed, the sequential venous graft was checked again for blood leakage.
CON group
When obtaining the great saphenous vein, the surrounding tissue was not preserved, and the branches were treated in the same way as in the NT group. After harvesting, the vein was manually dilated with a syringe filled with heparin saline to check for branch leakage. The remaining operation procedures were the same as those used for the NT group.
CCTA Evaluation of Graft Patency
One year after the operation, cardiac computed tomography angiography (CCTA) was performed to evaluate the patency rate of the sequential venous grafts. The venous patency rate was evaluated by the FitzGibbon classification system[18]. FitzGibbon-A refers to a wide range of unobstructed grafts or less than 50% narrow grafts; FitzGibbon-B is a limited flow graft with a narrowing higher than 50%. FitzGibbon-O refers to an occlusive graft without blood flow. In this study, FitzGibbon-A/B was used for patency, and FitzGibbon-O was used for graft failure. The diseased graft was also regarded as a lesion if the lesion was located at the proximal/distal anastomosis site or the graft trunk.
Evaluation of Clinical Outcomes
First, the incidence of postoperative complications, such as atrial fibrillation, acute kidney injury, and reoperation, was compared between the two groups. In addition, leg wound complications 3 months after the operation and the occurrence of MACCEs 1 year after the operation were evaluated.
Statistical Analysis
SPSS 22.0 for Mac (IBM SPSS Statistics) was used for statistical analyses. Continuous variables are reported as the mean +/− standard deviation or median (interquartile range) (IQR). Categorical variables were reported as the absolute frequency and as a percentage. Student’s t-test was applied for continuous data with equal or unequal variances. The Mann-Whitney U test was applied for continuous data that were not normally distributed. Pearson’s 2 and Fisher’s exact tests were used for categorical data. Statistical significance was accepted at p<0.05.