Nonreversed saphenous vein grafts for coronary artery bypass grafting

Between August 1985 and December 1988, valvotomized saphenous vein grafts were used in 365 patients undergoing coronary artery bypass grafting (CABG). In this operation, the femoral end of the vein is attached to the aorta and the pedal end is attached to the coronary artery. Vein diameters measured 8 +/- 2 mm at the femoral end, 4.5 +/- 1.2 mm at the knee level, and 3.5 +/- 1.3 mm at the ankle. Ratios between levels were as follows: knee to femoral end, 0.56, and ankle to femoral end, 0.43. The ratio of knee to femoral end was 0.42 in cases with vein midthigh bifurcation. There were 1,310 grafts implanted (3.6 per patient). In 341 patients, CABG alone was performed, and 24 patients had combined procedures: 11 had CABG with mitral valve replacement, 9 had CABG with aortic valve replacement, 2 had CABG with repair of postinfarct ventricular septal defect, and 2 had CABG with automatic defibrillator implantation. Follow-up (up to 3.5 years) was attained in 97% of patients. For various reasons, 34 patients had a second angiogram between 3 and 41 months postoperatively. Of 120 vein grafts, 108 (90%) were patent. At autopsy, 11 patients with 45 vein grafts had 43 patent and clean grafts and two thrombosed. Use of nonreversed saphenous vein for coronary bypass is recommended. It assures a large proximal anastomosis, natural vein bifurcations can be used with fewer proximal anastomoses, better vein-coronary artery size matching is obtained, and the patency rate is satisfactory.     

Long-term patency of sequential and individual saphenous vein coronary bypass grafts.

OBJECTIVES: The long-term patency rates for individual and sequential saphenous vein grafts (SVG) as coronary bypass conduits are angiographically compared; the impact of native coronary vessel characteristics is investigated. METHODS: A total of 875 distal coronary anastomoses on 500 SVGs were assessed in 430 patients at an average of 5.8+/-3 years after a coronary revascularization procedure. RESULTS: The patency rates of sequential conduits were markedly higher than those of individual ones (82 vs. 68%, P=0.0005). Also, the anastomoses on the sequential conduits had better patency (75 vs. 68%, P=0.03). This difference was even more pronounced in coronary arteries of poor quality and small (<1.5 mm) diameter (57 vs. 28% for the sequential grafts and individual grafts, respectively, P=0.001). Also, when the most distally located coronary artery on a sequential graft was of poor run-off, the patency rate for the entire conduit was considerably low (42.5%). CONCLUSIONS: The patency of a sequential vein graft conduit is generally better than that of an individual one, especially for poor run-off coronary vessels, provided that the most distally located anastomosis is done on a good coronary artery in terms of quality and diameter. Using a minimal length of conduits is another advantage. However, failure of a single sequential conduit jeopardizes all the anastomoses along that graft segment. Besides, sequential grafting is technically more demanding, and the technical expertise in performing a sequential anastomosis is probably among the important determinants of short- and long-term patency.     

Intraoperative ultrasonic imaging of coronary artery and saphenous vein grafts in coronary bypass surgery

The intraoperative evaluation of native coronary atherosclerotic lesions and the anastomotic status of saphenous vein grafts were made using two-dimensional echography. Ultrasonic imaging was performed with a linear cross-sectional ultrasonograph and a high-frequency wide-brand microtransducer. In animal experiments, the lumens of the left main trunk and other major branches of coronary arteries of mongrel dogs were clearly visualized; the stenotic portion created by external constriction of the left anterior descending artery was also recognized in this manner. In the clinical application, 30 patients who required coronary artery this manner. In the clinical application, 30 patients who required coronary artery bypass grafting were examined during surgery. Intraluminal status of the left main trunk and proximal to mid portion of the other major coronary arteries were visualized satisfactorily. Stenotic portions detected by preoperative coronary cine-angiography were recognized. It was concluded that intraoperative echo coronary arteriography provides adequate information on the target coronary artery before the incision is made and that evaluation of anastomotic status is possible.     

Technical considerations in saphenous vein bypass grafts to the right coronary artery.

Measurement of the proper length for saphenous vein bypass grafts to the right coronary artery can be complicated by the increase in cardiac volume that takes place when extracorporeal circulation is discontinued. Inadequate or excessive allowance for this increase can cause undue tension on the grafts or troublesome kinking. This report describes an improved method of orienting vein bypass grafts to the right coronary artery which eliminates problems of incorrect measurement.     

Functional assessment of disease-free saphenous vein grafts at redo coronary artery bypass grafting

BACKGROUND: Reoperations for coronary artery bypass grafting are on the rise. The general rule of replacing all saphenous vein grafts (SVGs) older than 5 years of age at the time of reoperation has recently been challenged on clinical grounds. This study provides functional data of endothelial behavior in long-term vein grafts. METHODS: Previously placed SVGs were removed at the time of redo operations. Nitric oxide (NO) measurements in real time were carried out before and after stimulation with morphine. The measurements were compared to the angiographic appearance of the grafts obtained prior to operation. Grafts were categorized into 3 groups: disease-free, moderately diseased, and severely diseased. RESULTS: Sixteen grafts were analyzed. Five were angiographically disease-free, 4 had moderate, and 7 severe disease. In the disease-free group, peak NO production after 10(-6) mol/L morphine stimulation was 35 mol/L, equivalent to the production of native saphenous vein. The severely diseased group did not demonstrate an increase in NO production, and the moderately diseased group produced a small rise in production. CONCLUSIONS: Measurement of NO release of old SVGs, when angiographically pristine, equals that of native saphenous vein. These findings support the recent clinical observations that long-term angiographically disease-free vein grafts are biologically privileged.     

Percutaneous transluminal angioplasty of coronary saphenous vein bypass grafts

Between December 1981 and August 1983, percutaneous transluminal angioplasty of saphenous vein grafts was performed in 14 men and 4 women, selected because of recurrent anginal symptoms and graft stenosis. The interval from bypass to angioplasty was 41 +/- 36 months. Of 24 lesions, 9 were at the proximal anastomosis, 13 in the distal segment and 2 in the middle segment of the vein graft. The primary success rate was 79%. Failure to cross the stenosis occurred in three patients and failure to dilate in one. The stenosis was reduced from a mean of 82% +/- 13% to 26% +/- 15%. No patient required emergency coronary artery bypass grafting but two underwent elective grafting after the angioplasty had failed. No patient sustained a Q-wave myocardial infarction and all who had a successful angioplasty were asymptomatic or much improved after the procedure. Angiographic follow-up was available in 12 of 14 patients (86%). Six patients had significant symptoms (Canadian Cardiovascular Society class II to III) and five of these had evidence of restenosis. Among the six patients who were asymptomatic, two had angiographic evidence of restenosis. The overall rate of restenosis was 58% (7 of 12). Repeat angioplasty was successful in three of the five patients in whom it was attempted. The authors conclude that percutaneous transluminal angioplasty of a saphenous vein graft for a localized area of stenosis is effective and safe, but there is a high rate of restenosis that possibly is due to intimal fibrous proliferation in saphenous vein grafts.     

Long-term clinical outcomes after coronary artery bypass grafting with pedicled saphenous vein grafts

Background

Coronary artery bypass grafting (CABG) using saphenous vein grafts (SVG) is vitiated by poor long-term patency of the vein grafts. Pedicled SVG harvested with the “no-touch” (NT) technique have demonstrated improved patency and could confer better outcomes. We aim to compare long-term results after CABG where NT or conventional technique was used for vein graft harvesting in a hypothesis-generating registry-based study.

Methods

Two propensity score matched cohorts (1349 patients) undergoing CABG with veins harvested with NT (NTT) or conventional (CT) technique in Sweden over the period 2005–2015 were used to compare long-term outcomes. Mortality, postoperative incidence of coronary angiography and need for reintervention was recorded and multivariable hazard ratios adjusted for risk factors were calculated.

Results

The mean follow-up time (SD) was 6.8 (3.3) years for NTT and 6.6 (3.2) years for CT. The adjusted hazard ratios for death, first angiography and need for reintervention for NTT patients were (95% CI) 0.97 (0.80–1.19), 0.76 (0.63–0.93), 0.91 (0.78–1.05), and 0.91 (0.71–1.17), respectively. Failed grafts were found in 43.2% of NTT patients and 53.6% of CT patients at angiography.

Conclusions

In this study NT grafting was associated with a lower risk for repeat angiography, however no difference could be observed for mortality and need for reintervention. The earlier reported improvements in patency of NT veins could possibly be reflected in an improved clinical outcome during the first 10?years after surgery.

     

Thrombomodulin activity on human saphenous vein grafts prepared for coronary artery bypass.

Thrombomodulin, a membrane glycoprotein present on normal vascular endothelium, binds circulating thrombin and is important in protein C activation. These functions contribute to the nonthrombogenic nature of endothelium. Damage during harvest and ex vivo storage of vein grafts may result in dysfunction of this endothelial anticoagulant barrier and possibly contribute to early graft thrombosis. We studied the functional activity and antigenic expression of thrombomodulin on saphenous veins before (initial) and after (harvested) harvest and storage for coronary artery bypass grafting in 15 patients. Also, fresh saphenous vein was studied after mechanical endothelial stripping. After storage for 2.7 +/- 0.6 hours at room temperature in heparinized saline, thrombomodulin functional activity in harvested vein segments was 28% less than initial segments (p = 0.08). Endothelial stripping resulted in a 79% reduction in thrombomodulin activity compared with initial segments (p = 0.04). Immunohistochemical staining confirmed thrombomodulin antigen on vein grafts after harvest and storage, but not on segments stripped of endothelium. Thrombomodulin functional activity and antigenic expression on human saphenous vein grafts is not significantly changed by harvest and relatively short periods of storage at room temperature in heparinized saline.     

High early patency of saphenous vein graft for coronary artery bypass harvested with surrounding tissue

BACKGROUND: Surgical trauma to the saphenous vein, used as a conduit for coronary artery bypass grafting, affects their occlusion rate. This study evaluates the early patency of saphenous vein grafts harvested with a pedicle of surrounding tissue that protects the vein from spasm and trauma. METHODS: Fifty-two patients underwent coronary artery bypass grafting with saphenous veins harvested with surrounding tissue. Forty-five patients, who received a total of 124 vein grafts and 42 left internal mammary arteries, underwent angiographic follow-up at a mean of 18 months (9 to 24 months). RESULTS: Patency for saphenous vein grafts was 95.4% and for left internal mammary arteries, it was 93.3%. Twenty-nine of 30 (96.7%) vein grafts anastomosed to arteries 2.0 mm or more, 65 of 67 (97%) grafts to 1.5 mm, and 10 of 13 (77%) anastomosed to 1-mm arteries were patent. Nineteen of 22 (86.4%) vein grafts with flow rates 20 mL/min or less, 32 of 34 (94.1%) with flow between 20 and 40 mL/min, and 50 of 51 (98%) with flow more than 40 mL/min were patent. Other registered surgical and clinical factors did not contribute to vessel occlusion. CONCLUSIONS: Early patency rate of saphenous veins harvested with surrounding tissue is very high, even in saphenous vein grafts demonstrating low blood flow. Preservation of graft endothelium using our harvesting technique may be the explanation of this success.     

Patency of sequential and individual saphenous vein grafts after off-pump coronary artery bypass grafting

Abstract Background: The impact of the grafting techniques (individual or sequential grafts) on the graft patency of off‐pump coronary artery bypass grafting (OPCAB) has not been reported. The mid‐term patency rates for individual and sequential saphenous vein grafts (SVGs) as coronary bypass conduits of OPCAB were compared. Methods: A total of 714 distal coronary anastomoses on 448 SVGs were assessed using a 64‐multislice computed tomography in 398 patients at an average of 26.4 ± 23.6 months (three months to five years) after an OPCAB procedure. The blood flow of grafts in the proximal segment of individual and sequential SVGs was also compared. Results: The overall patency of sequential SVGs (95.9%) was significantly superior to individual ones (90.6%, p = 0.022). The anastomoses on the sequential conduits had better patency (95.1% vs. 90.1%, p = 0.013). The patency of side‐to‐side anastomoses (97%) was better than that of end‐to‐side anastomoses (93.1%) and also better than that of the individual end‐to‐side anastomoses (90.1%, p = 0.002, p = 0.041). No significant difference was observed between the two approaches in regard to the three major coronary systems; however, anastomoses on sequential grafts had superior patency to those on individual grafts in the right coronary system (p = 0.008). The blood flows of double and triple sequential SVGs were significantly higher than those of individual ones (p < 0.001, p = 0.048, respectively). Conclusions: The mid‐term patency of a sequential SVG conduit after OPCAB is excellent and generally superior to that of an individual one. (J Card Surg 2010;25:633‐637)     

Cryopreserved homologous saphenous vein: early and late patency in coronary artery bypass surgical procedures

Autologous saphenous vein has proved to be a satisfactory conduit for use in coronary artery bypass grafting. Unfortunately, it is not always available, and substitute material must sometimes be used. When satisfactory autologous veins were not available and the internal mammary arteries were unsuitable, cryopreserved homologous saphenous veins were used in 28 patients. A total of 76 grafts were constructed. Cryopreserved homologous veins were used for 61 grafts, autologous saphenous veins for 11 grafts, and the internal mammary artery for 2 grafts. Coronary angiography was performed 8 to 12 days postoperatively in 16 patients. Of the 31 homografts studied, 8 were occluded (26%), 3 were stenotic (9%), and 20 were normal (65%). The one internal mammary artery and six autologous veins studied were all patent. Six patients underwent late catheterization 6 to 12 months postoperatively. Thirteen homografts were studied at late catheterization: 11 were occluded, 1 was severely stenotic, and 1 was mildly stenotic. At late catheterization, the one internal mammary artery studied was patent, and the one autologous saphenous vein was 95% occluded. Results of both early and late catheterization performed on 18 patients demonstrated that of the 35 homografts studied, 17 (49%) were occluded, 3 (9%) had greater than 70% stenosis, 1 (3%) had mild disease, and 14 (40%) were free of disease. One year follow-up data obtained on 26 patients revealed that 4 patients (15%) died of cardiac causes, 2 patients (8%) died of noncardiac causes, 11 patients (42%) have recurrent angina, and 9 (35%) are asymptomatic. It is concluded that use of cryopreserved homologous saphenous veins for coronary artery bypass grafting should be avoided if at all possible.     

Off-pump coronary artery bypass

OBJECTIVES: Off-pump coronary artery bypass grafting (CABG) on the beating heart has become popular procedure in cardiac surgery and its initial results appeared favorable. We report our early and mid-term results of off-pump CABG performed at Shin-Tokyo Hospital. METHODS: Medical records of patients undergoing off-pump or conventional on-pump CABG from September 1, 1996, to August 31, 1999 were retrospectively reviewed. Patients underwent off-pump CABG were further classified into 2 groups; MIDCAB (Off-pump CABG for single vessel revascularization via a small skin incision) and OPCAB (off-pump CABG mainly approached via midline sternotomy) group. Their preoperative, perioperative, and follow-up data were collected and analyzed. RESULTS: Among a total of 995 cases of CABG, 194 cases were off-pump CABG (male/female 142/52, mean age 66.9). The mean number of distal anastomoses in off-pump CABG was 1.9 +/- 0.9 (1.0 +/- 0.0 in MIDCAB and 2.3 +/- 0.7 in OPCAB), which was significantly fewer than in on-pump CABG (3.6 +/- 1.1), with p < 0.0001. Intubation time (5.3 +/- 5.7 hours in off-pump CABG vs 13.1 +/- 24.2 hours in on-pump CABG), ICU stay (1.7 +/- 1.1 vs 3.2 +/- 3.0 days), and postoperative hospital stay (14.0 +/- 7.9 vs 18.1 +/- 12.1 days) in off-pump CABG were significantly shorter than in on-pump CABG (p < 0.0001). In the off-pump CABG group, there were no in-hospital deaths and 14 major complications, fewer than in on-pump CABG (8 hospital deaths and 114 major complications). Postoperative angiography before hospital discharge was conducted in 80 patients (41.2%) and showed 2 occlusions, giving a graft patency rate of 98.6% in the off-pump group. During follow-up (0.9 +/- 0.6 year) period, there were 5 non-cardiac deaths and 20 cardiac events in the off-pump group. The actuarial survival rate at 36 months was 94.6% for off-pump CABG, showing no significant difference from the rate for conventional CABG patients (95.2% at 36 month, p = NS) The event-free rate was 84.0% at 36 months in off-pump CABG patients; however, which was less favorable than on-pump CABG patients (88.0% at 36 months, p < 0.05). CONCLUSIONS: Both in-hospital and mid-term results for off-pump CABG patients were acceptable. Isolated CABG can thus be safely performed without cardiopulmonary bypass. Advances in coronary stabilization have contributed to these improved results. The observed long-term cardiac events may be related to incomplete revascularization.     

Long-term patency of aorto-coronary saphenous vein grafts]

One hundred eighty-two cases with 814 aorto-coronary saphenous vein grafts were studied according to coronary risk factors (smoking, hypertension, hyperlipidemia, diabetes mellitus, obesity and family history). The patency rates of all cases were as follows, early-term (within one year after operation): 92.3%, mid-term (within 5 years after operation) 80.7%, long-term (more than 5 years after operation): 66.0%. Coronary risk factors have great influence upon the mid- and long-term patency, especially upon the latter. The long-term patency rate of the grafts complicated with hyperlipidemia was 57.4% and that without hyperlipidemia was 81.8% (p less than 0.01). Hyperlipidemia, complicating 55.5% of all cases, was one of the most influential factors on the patency and also the most difficult one to be controlled. In the United States and Europe, many cases were complicated with hyperlipidemia, and it was considered that the poor patency of the saphenous vein grafts in those countries was due to this fact. Pathological studies revealed that hyperplasia of intima and media, characteristics of venosclerosis, appeared frequently in the saphenous vein grafts having more than three risk factors, and that the factors had effect not only upon arteries but also upon veins. So we conclude that saphenous vein grafts are the materials of good long-term patency, and that the control of the risk factors, particularly hyperlipidemia, is the key to improve the patency.