We have reviewed the development and current status of therapies based on exposure to non-ionizing radiation (with a photon energy less than 10 eV) aimed at suppressing the venous neointimal hyperplasia, and consequentially at avoiding stenosis in arteriovenous grafts. Due to the drawbacks associated with the medical use of ionizing radiation, prominently the radiation-induced cardiovascular disease, the availability of procedures using non-ionizing radiation is becoming a noteworthy objective for the current research. Further, the focus of the review was the use of such procedures for improving the vascular access function and assuring the clinical success of arteriovenous fistulae in hemodialysis patients. Following a brief discussion of the physical principles underlying radiotherapy, the current methods based on non-ionizing radiation, either in use or under development, were described in detail. There are currently five such techniques, including photodynamic therapy (PDT), far-infrared therapy, photochemical tissue passivation (PTP), Alucent vascular scaffolding, and adventitial photocrosslinking. The last three are contingent on the mechanical stiffening achievable by the exogenous photochemical crosslinking of tissular collagen, a process that leads to the decrease of venous compliance. As there are conflicting opinions on the role of compliance mismatch between arterial and venous conduits in a graft, this aspect was also considered in our review.

The no-touch saphenous vein with surrounding pedicle tissue harvesting technique preserved endothelium and vessel wall integrity and demonstrated improved long-term saphenous vein conduit patency that was comparable to internal thoracic artery conduit patency. Despite improved saphenous vein conduit patency rates, there is a possibility that no-touch saphenous vein harvest may increase wound complication rates by increased tissue disruption, including venous and lymphatic channels. Comprehensive strategies to minimize leg wound complications after no-touch saphenous vein harvest are discussed.

Although the saphenous vein is a widely used conduit for coronary artery bypass grafting, revascularization using the saphenous vein as an aortocoronary bypass graft has shown disadvantages of lower long-term graft patency rates and subsequently worse clinical outcomes, compared with revascularization using the internal thoracic artery. Of the various efforts to overcome the limitations of vein conduit that are resulting from structural and functional differences from arterial conduit, recent technical improvement in no-touch vein composite graft construction and outcomes of revascularization using no-touch vein composite grafts based on the left internal thoracic artery will be discussed in this topic.

We assessed the incidence of competitive flow with early postoperative angiograms in patients who received a \"no-touch\" saphenous vein (NT SV) composite graft and reexamined the status of competitive flow at 1-year. Early postoperative angiograms were performed in 806 patients who underwent myocardial revascularization using a NT SV Y-composite graft based on the in situ left internal thoracic artery (LITA). Competitive conduit flow was observed in 102 distal anastomoses (102 of 3039 [3.4%] anastomoses) of 94 patients (94 of 806 [11.7%]; NT SV competitive flow in 74 and LITA competitive flow in 20). Of the 94 patients, 63 patients (50 with NT SV competition and 13 with LITA competition) were re-evaluated with 1-year postoperative angiograms. Fifty-six competitive NT SV conduits in 50 patients were reevaluated at 1-year postoperatively: 44 (78.6%) early competitive anastomoses had become patent and 12 (21.4%) were occluded. NT SV with pedicle tissue showed a higher tendency of being perfectly patent at 1-year postoperatively than NT SV without pedicle tissue (17 of 40 [42.5%] vs 2 of 16 [12.5%]; P = 0.007). Thirteen competitive LITA conduit anastomoses in 13 patients were reevaluated 1-year postoperatively: 9 (69.2%) early competitive anastomoses had become patent and 4 (30.8%) were occluded. Competitive flow was shown on early postoperative angiograms in 3.4% of distal anastomoses in patients who received NT SV Y-composite grafts. Approximately 80% of the competitive NT SV conduits were patent 1-year postoperatively, and perfect patency rates were higher in patients who had received NT SV with pedicle tissue than in patients who had received NT SV without pedicle tissue.

暂无摘要。

BACKGROUND: We have observed reopening of the occluded \"no-touch\" saphenous vein (NT SV) composite grafts on follow-up angiograms in patients who underwent coronary artery bypass graftings (CABGs).
METHODS: Between 2008 and 2018, 1283 patients received NT SV conduits without or with surrounding pedicle tissue as composite grafts based on the in situ left internal thoracic artery (ITA) for CABG and underwent early postoperative angiographies. Among the 1283 patients, 53 patients showed 55 occluded SV conduit anastomoses, and 46 patients who had 48 occluded SV anastomoses were re-evaluated by 1-year postoperative angiographies.
RESULTS: Early postoperative angiographies in 1283 patients demonstrated overall occlusion rates of 1.2% (56/4518); occlusion rates of the ITA and SV were 0.08% (1/1259) and 1.7% (55/3260), respectively. One-year angiograms demonstrated that 14 occluded SV anastomoses (29.2% [14/48 occluded SV]) of 14 patients became patent. Reopening of occluded SV conduits occurred more frequently in NT SV with pedicle tissue than in NT SV without pedicle tissue (45.0% [9/20] vs. 17.9% [5/28]; p = .057). When we examined the preoperative and 1-year postoperative angiograms, reopening of the occluded SV conduits was not related with progression (p = .258) or preoperative reversibility score (p = .115) of native target coronary artery disease.
CONCLUSIONS: More than a quarter of the occluded SV composite grafts on early postoperative angiograms were patent in the 1-year angiograms. The reopening rates were higher in patients who had received NT SV conduits with pedicle tissue than those who had received NT SV conduits without pedicle tissue.

OBJECTIVE: Little data exist regarding the potential of external stents to mitigate long-term disease progression in saphenous vein grafts. We investigated the effect of external stents on the progression of saphenous vein graft disease.
METHODS: A total of 184 patients undergoing isolated coronary artery bypass grafting, using an internal thoracic artery graft and at least 2 additional saphenous vein grafts, were enrolled in 14 European centers. One saphenous vein graft was randomized to an external stent, and 1 nonstented saphenous vein graft served as the control. The primary end point was the saphenous vein graft Fitzgibbon patency scale assessed by angiography, and the secondary end point was saphenous vein graft intimal hyperplasia assessed by intravascular ultrasound in a prespecified subgroup at 2 years.
RESULTS: Angiography was completed in 128 patients and intravascular ultrasound in the entire prespecified cohort (n = 51) at 2 years. Overall patency rates were similar between stented and nonstented saphenous vein grafts (78.3% vs 82.2%, P = .43). However, the Fitzgibbon patency scale was significantly improved in stented versus nonstented saphenous vein grafts, with Fitzgibbon patency scale I, II, and III rates of 66.7% versus 54.9%, 27.8% versus 34.3%, and 5.5% versus 10.8%, respectively (odds ratio, 2.02; P = .03). Fitzgibbon patency scale was inversely related to saphenous vein graft minimal lumen diameter, with Fitzgibbon patency scale I, II, and III saphenous vein grafts having an average minimal lumen diameter of 2.62 mm, 1.98 mm, and 1.32 mm, respectively (P < .05). Externally stented saphenous vein grafts also showed significant reductions in mean intimal hyperplasia area (22.5%; P < .001) and thickness (23.5%; P < .001).
CONCLUSIONS: Two years after coronary artery bypass grafting, external stenting improves Fitzgibbon patency scales of saphenous vein grafts and significantly reduces intimal hyperplasia area and thickness. Whether this will eventually lead to improved long-term patency is still unknown.

Introduction The long-term patency of the grafts used during the coronary artery bypass grafting (CABG) is one of the most significant predictors of the clinical outcomes. The gold standard graft used during CABG with the best long-term patency rate and the better clinical outcomes is left internal thoracic artery (LITA) grafted to the left coronary artery (LCA). The controversy lies in choosing the second-best conduit for the non-left coronary artery (NLCA) with similar patency rate as LITA. This meta-analysis examines the long-term patency and clinical outcomes of all arterial grafts versus all venous grafts used during the CABG. Methods A comprehensive literature search of all published randomized control trials (RCTs) assessing long-term patency and clinical outcomes of grafts used in CABG was conducted using PubMed, Cochrane Central Registry of Controlled Trials, and Google Scholar (1966-2018). Keywords searched included combinations of \"CABG\", \"venous grafts in CABG\", \"arterial grafts in CABG\", \"radial artery grafts in CABG\", \"gastroepiploic artery grafts in CABG\", \"patency and clinical outcomes\". Inclusion criteria included: RCTs comparing the long-term patency, and clinical outcomes of radial artery, right internal thoracic artery, gastroduodenal artery, and saphenous vein grafts used in CABG. Long-term patency of the grafts and clinical outcomes were analyzed. Results Eight RCTs involving 2,091 patients with 1,164 patients receiving arterial grafts and 927 patients receiving venous grafts were included. There was no difference between the long-term patency rate (relative risk (RR) = 1.050, 95% confidence interval (CI) = 0.949 to 1.162, and p = 0.344), overall mortality rate (RR = 1.095, 95% CI = 0.561 to 2.136, and p = 0.790), rate of myocardial infarction (MI) (RR = 0.860, 95% CI = 0.409 to 1.812, and P = 0.692), and re-intervention rate (RR = 0.0768, 95% CI = 0.419 to 1.406, and P = 0.392) between arterial and venous grafts. Conclusion The use of arterial conduits over the venous conduits has no significant superiority regarding the long-term graft patency, the rate of MI, overall mortality, and the rate of revascularization following CABG. Additional adequately powered studies are needed to further evaluate the long-term outcomes of arterial and venous grafts following the CABG.

Angiographically visible plaques in patent vein grafts are usually detected years after surgery. Our aim was to examine early plaque formation in vein grafts.
Bypass angiography and intravascular ultrasonography (IVUS) examination were performed on 77 aortocoronary saphenous vein grafts (SVGs) implanted in 36 patients during the first 2 years after CABG. In each graft, a good quality 25 mm ultrasound image was analyzed. We measured: plaque area, lumen area, external elastic membrane (EEM) area, graft area and wall area. For the comparative assessment of SVGs, the index plaque area/EEM area was calculated. Data were analyzed for the following 4 time periods: I - 0-4 months (22 grafts), II - 5-8 months (23 grafts), III - 9-12 months (19 grafts) and IV - 13-16 months (13 grafts) after CABG. Student\'s t and Fisher-Snedecor tests were used for the purpose of statistical analysis in this retrospective study.
In period I, plaque formation (neointimal) was observed in 10 grafts (45%), with a mean plaque area of 1.59 mm., in 6 grafts (26%) in period II, with a mean plaque area of 1.03 mm. and in 15 grafts (71%) in period III, with a mean plaque area of 1.41 mm., and in all (100%) grafts in period IV, with mean plaque area of 2,3 mm.. Average index plaque area/EEM area in periods I, II, III and IV were 0.12, 0.08, 0.13 and 0.22. We have showed a significant plaque increase between periods II and IV(P=0.038).
IVUS showed plaque in about 40% of venous grafts during the first year after CABG. Between 13-16 months plaque was visible in all studied grafts.

Hemodynamic compromise immediately after chest closure can be potentially fatal event. Such condition warrants urgent reopening of sternum. In the present case, we discover An uncommon cause of unstable hemodynamics.