The short saphenous vein: an alternative to the long saphenous vein for aortocoronary bypass.

The long saphenous vein and internal mammary artery are considered at present to be the best grafts available for coronary artery bypass. Patients who have had bilateral long saphenous vein stripping and who require multiple aortocoronary bypass grafts present a challenge to the cardiac surgeon. The short saphenous vein appears to be a suitable alterative.     

Gene delivery to aortocoronary saphenous vein grafts in a large animal model of intimal hyperplasia

OBJECTIVE: More than 50% of aortocoronary saphenous vein grafts are occluded 10 years after surgery. Intimal hyperplasia is an initial, critical step in the progression toward occlusion. To date, no clinically relevant large animal models of aortocoronary saphenous vein graft intimal hyperplasia have been fully characterized. Gene therapy holds promise as a novel treatment for aortocoronary saphenous vein graft intimal hyperplasia. The 2 objectives of this study are to characterize a canine model of aortocoronary saphenous vein graft intimal hyperplasia and to demonstrate that ex vivo gene delivery is possible in these grafts using adenoviral vectors. METHODS: Ten dogs underwent aortocoronary bypass grafting using saphenous veins. Six dogs underwent serial arteriograms to monitor graft patency. On postoperative day 90, the dogs were killed and their grafted and nongrafted saphenous veins were studied histologically. Four dogs underwent the same procedure, but their saphenous veins were treated with 1 x 10(12) total viral particles of a replication-deficient, recombinant adenovirus containing beta-galactosidase (n = 2) or the beta-adrenergic receptor kinase carboxyl terminus (n = 2). These animals were killed on postoperative day 7 for determination of transgene expression. RESULTS: All grafts were demonstrated patent by arteriogram before the animals were killed. The mean intimal area of the saphenous vein grafts was increased when compared with that of the nongrafted saphenous veins (2.83 mm(2) vs 0.09 mm(2), P <.0008). Adenoviral-treated saphenous vein grafts demonstrated positive transgene expression either by X-gal staining (beta-galactosidase) or Northern analysis (beta-adrenergic receptor kinase carboxyl terminus). CONCLUSION: This study characterizes a clinically relevant canine model of aortocoronary saphenous vein graft intimal hyperplasia. In addition, it demonstrates that adenoviral vectors can be delivered ex vivo to the saphenous vein graft vessel wall at subphysiologic distension pressures. This model may be used in future studies to manipulate molecular targets critical in aortocoronary saphenous vein graft intimal hyperplasia.     

Immunohistochemical and ultrastructural evidence that dendritic cells infiltrate stenotic aortocoronary saphenous vein bypass grafts

We earlier speculated that antigen-presenting dendritic cells may be involved in the immune reactions leading to saphenous vein bypass graft failure. The purpose of this study was to confirm whether dendritic cells are present in stenotic human saphenous vein bypass grafts. Segments of stenotic saphenous vein grafts were explanted from 14 patients at re-do bypass operation and ten normal saphenous veins were harvested during femoro-popliteal grafting. Sections of specimens were analysed using cell type specific antibodies to identify dendritic cells (CD1a, S-100), T-lymphocytes (CD3), macrophages (CD68), smooth muscle cells (alpha-SMA) and endothelial cells (FVIII). Dual immunostaining, confocal immunofluorescent laser scanning microscopy and electron microscopy were used. Stenotic grafts showed structural alterations of intimal hyperplasia and varying degrees of atherosclerotic degeneration. No cells expressing CD1a and S-100 were observed in the intima and media of normal saphenous veins. Cells expressing these antigens were present around areas of medial neovascularization and within intimal atherosclerotic lesions in saphenous vein bypass grafts. Electron microscopy demonstrated the presence of cells containing a well-developed tubulovesicular system which is unique to cells from the dendritic cell family. Double immunohistochemistry and confocal immunofluorescent microscopy revealed the co-localization of T-lymphocytes with dendritic cells. Dendritic cells are present in stenotic saphenous vein bypass grafts. Dendritic cells may be responsible for antigen presentation and modulation of immune reactions in accelerated graft atherosclerosis through their interaction with T-lymphocytes.     

Long-term results of coronary artery bypass grafting: comparison of angiographic evaluation of internal thoracic artery and saphenous vein grafts

The long term (10 to 15 years) results of coronary artery bypass grafting (CABG) were studied in 20 patients. The duration of follow-up was ranged from 130 to 170 months with mean 146.4 months. Ten out of 20 patients underwent coronary angiography (CAG), which disclosed that the late patency of saphenous vein (SV) grafts was 68.8% (11/16), but 54.5% (6/11) of patent SV grafts showed atherosclerotic changes such as irregularity and localized narrowing. On the other hand, internal thoracic artery (ITA) grafts were all patent without any atherosclerotic luminal changes. We recognized that ITA grafts were superior to SV grafts from an angiographic standpoint of view in the long term in Japan.     

Evaluation of aortocoronary bypass operation using a He-Ne laser flowmeter--comparison between internal mammary artery grafts and saphenous vein grafts

It was very difficult to measure myocardial blood flow in clinical cases. Recently, a He-Ne laser doppler flowmeter was developed, and we made it possible to measure the pre-and post-operative myocardial blood flow in cases of coronary artery bypass grafting (CABG). We applied a laser flowmeter to 30 cases of bypass grafting to the left anterior descending coronary artery (18 cases with IMAG and 12 cases with SVG). The preoperative myocardial blood flow at the right ventricular anterior wall was 77 +/- 15 ml/min/100 gr, and the postoperative flow at the same point was 81 +/- 12 ml/min/100 gr. There was no significant change between the pre-operative value and the postoperative one. Myocardial blood flow at the left ventricular anterior wall in SVG group significantly increased from the preoperative value of 58 +/- 11 ml/min/100 gr to the postoperative value of 86 +/- 9 ml/min/100 gr (p less than 0.001). In IMAG group, myocardial blood flow at the left ventricular anterior wall similarly increased from 73 +/- 14 ml/min/100 gr to 83 +/- 15 ml/min/100 gr (p less than 0.01). The postoperative value of IMAG group was almost equal to the value of SVG group. The increased rate of myocardial blood flow at the left ventricular anterior wall was 52 +/- 32% in SVG group and 18 +/- 12% in IMAG group. These rates were obviously distinguished from the increased rate at the right ventricular anterior wall.(ABSTRACT TRUNCATED AT 250 WORDS)     

Composite Y internal thoracic artery-saphenous vein grafts: short-term angiographic results and vasoreactive profile

BACKGROUND: The angiographic patency of composite Y internal thoracic artery-saphenous vein grafts has not been investigated in detail. METHODS: Twenty-five patients who received composite Y internal thoracic artery-saphenous vein grafts had control angiography and vasoactive challenges with serotonin, acetylcholine, and isosorbide dinitrate at a mean of 2.5 +/- 1.2 years after surgery. RESULTS: The perfect patency rate of composite Y internal thoracic artery-saphenous vein grafts was 72% (18/25). The distal portion of the internal thoracic artery was stringed in 4 patients and occluded in 2. The saphenous branch of the composite Y internal thoracic artery-saphenous vein grafts was found patent in all patients except 1. No failures were reported in the proximal tract of the internal thoracic artery. The distal tract of the internal thoracic artery showed reduced capacity of endothelium-mediated relaxation. CONCLUSION: The short-term patency of composite Y internal thoracic artery-saphenous vein grafts is suboptimal and markedly influenced by distal runoff and native flow competition.     

Initial results on the use of mechanical devices for proximal saphenous vein graft anastomoses: a clinical and angiographic evaluation

Objective: To report on our initial clinical experience of the utilization of a mechanical anastomotic device (MAD) to perform saphenous vein graft to aorta anastomosis. Method: Between June 2002 and May 2003, 17 patients, including 13 male, with a mean age of 64.4 +/- 9.4 years, were selected for coronary artery bypass grafting using MAD. A total of 49 anastomoses, 19 arterial and 30 vein grafts, were performed with a mean of 2.9 +/-0.5 anastomoses per patient. Eleven (36.7%) vein-graft anastomoses were performed with conventional sutures and 19 (63.3%) using MAD. The clinical evolution, enzymatic and electrocardiographic alterations as well as an angiographic study were analyzed in the postoperative period. Results: Of the 17 patients, the mechanical device was used on 16 (94.1%). Six (37.5%) patients were operated on under cardiopulmonary bypass with a mean time of 102.9 +/-16.9 minutes. The postoperative evolution was satisfactory in all patients. No patient presented with enzymatic, myocardial infarction or other ischemic electrocardiographic alterations in the immediate postoperative period. Early postoperative angiography was performed in 9 (52.9%) patients. The anastomoses of the left internal thoracic artery to left anterior descending artery were patent in all cases. Of the 15 saphenous vein grafts studied, 11 (73.3%) were performed using MAD, 9 (81.8%) of which were patent. All the 4 conventionally sutured vein anastomoses were patent. No hospital deaths occurred. In the late follow-up, 88.2% of the patients were free of cardiac-related events. Conclusions: MAD for vein graft-to-aorta anastomoses proved to be feasible, but a wider analysis of the benefits of its utilization regarding operative time, aggression to the patient, patency of the grafts and final cost are necessary.     

Aneurysm of aortocoronary saphenous vein graft: case report and literature review

True aneurysms of aortocoronary saphenous vein bypass grafts are a relatively rare complication of bypass surgery, but because the complications of thrombosis, embolization, or rupture are potentially fatal, this condition requires immediate surgical intervention. We describe a 78-year-old man who had undergone coronary bypass 15 years previously and who presented with a saphenous vein graft that was severely degenerated and aneurysmally enlarged throughout its course, measuring as much as 5 to 6 cm in certain locations. Redo coronary artery bypass grafting using the right and left internal thoracic arteries and resection of the aneurysm were performed. We also present a review of the literature regarding diagnosis, management, and treatment of this condition.     

Expression of apoptosis-related proteins and structural features of cell death in explanted aortocoronary saphenous vein bypass grafts.

This study aimed to investigate the features of cell death occurring in aortocoronary saphenous vein bypass grafts. Human aortocoronary saphenous vein bypass grafts with angiographic luminal stenosis of > 75% were explanted from 14 patients at redo coronary artery bypass grafting. Proteins associated with apoptotic pathways were identified immunohistochemically using antibodies to Bcl-2, Fas, BAX, p53 and CPP32. Cells undergoing DNA fragmentation were identified by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). DNA synthesis was investigated using the antibody to proliferating cell nuclear antigen (PCNA). Ultrastructural features of cell death were examined by electron microscopy. Anti-apoptotic (Bcl-2) and pro-apoptotic (Bax, p53, CPP32 and Fas) proteins were expressed throughout the graft wall, but marked differences in the characteristics of cell death were noted between atherosclerotic and non-atherosclerotic areas of the intima. In atherosclerotic areas, pro-apoptotic proteins were widely expressed, but ultrastructural analysis failed to identify cells showing typical features of apoptosis. In these areas, necrotic cells were frequently observed, with negative correlation of Bcl-2 expression with TUNEL. Pro-apoptotic proteins showed no correlation with TUNEL. In contrast, in non-atherosclerotic areas of vein grafts, the expression of both anti-apoptotic (Bcl-2) and pro-apoptotic proteins (p53, Bax and CPP32) correlated with TUNEL. In atherosclerotic areas, non-atherosclerotic intimal areas, and in the underlying media, the numbers of TUNEL+ cells correlated with PCNA positivity. Ultrastructurally, apoptotic bodies and features of necrosis were observed in non-atherosclerotic areas of grafts. The present observations indicate that in atherosclerotic areas, cell death occurs mainly by necrosis, while in non-atherosclerotic areas, cell death occurs by both necrosis and apoptosis. An imbalance between DNA fragmentation and DNA synthesis may contribute to graft instability and failure.     

Prospectively randomized clinical trial to compare in situ and reversed saphenous vein grafts for femoropopliteal bypass

Two hundred and fifteen femoropopliteal bypass procedures using autologous saphenous vein grafts were randomly allocated to either the reversed or in situ technique. Eleven veins (5 per cent) were rejected at operation on the basis of their small size, nine in the reversed group and two in the in situ group, and there were two (2 per cent) perioperative deaths in each group, leaving 102 reversed and 98 in situ grafts for further study. The cumulative patency at 3 years of the reversed grafts was 77 per cent and that of the in situ grafts was 68 per cent (n.s.). The patency of all grafts was affected adversely by small veins (P less than 0.005), long grafts (P less than 0.05), low volume of blood flow in the grafts (P less than 0.001) and poor run-off (P less than 0.05). These factors influenced the outcome of the in situ and reversed operations to a similar degree and there was no statistically significant difference between them within any subgroup. The mean compliance of the in situ grafts measured 3 months or more after operation with an ultrasonic echo-tracking system was 0.024 +/- 0.01 per cent/mmHg (+/- s.d.) compared with 0.017 +/- 0.01 per cent/mmHg for the reversed grafts (t = 2.43, P less than 0.02). The incidence of fibrous stricture formation as shown by intravenous digital subtraction angiography was 29 per cent in both the reversed and the in situ grafts. The results of the study to date indicate that reversed and in situ vein grafts are equally effective for femoropopliteal bypass.     

Fractional flow reserve of pedicled internal thoracic artery and saphenous vein grafts 6 months after bypass surgery.

BACKGROUND: Although the internal thoracic artery was proven superior to saphenous vein graft in long-term patency, it is thought to be a more resistive conduit than the vein graft. Moreover, patency studies comparing both left and right internal thoracic arteries have provided results favoring the former. Fractional flow reserve is an established functional index of coronary blood flow. METHODS: To compare the fractional flow reserve between both internal thoracic arteries and saphenous vein grafts, 43 bypass grafts were studied 6 months after revascularization. Intra-graft pressures were measured during cardiac catheterization using a pressure-wire advanced to the first distal anastomosis of 12 left internal thoracic arteries (ITAs), 10 right ITAs and of 21 vein grafts. Pressure gradients between the aorta and the graft were measured at baseline and during a maximal hyperemia. RESULTS: At baseline, pressure gradient was recorded in the left ITA (2.9+/-2.2 mmHg), in the right ITA (1.2+/-1.2 mmHg) and in the vein graft (0.4+/-0.7 mmHg). During maximal hyperemia, pressure gradient increased to 9.6+/-3.2 mmHg in left ITA, to 4.5+/-2.0 mmHg in the right ITA (p<0.001 vs left ITA) and to 3.3+/-2.7 mmHg in vein (p<0.001 vs left ITA; NS vs right ITA). Fractional flow reserve was 0.90+/-0.04 in left ITA, 0.95+/-0.03 in right ITA (p<0.01 vs left ITA) and 0.96+/-0.03 in vein (p<0.001 vs left ITA). CONCLUSION: Internal thoracic arteries and saphenous vein grafts allow myocardial revascularization with minimal resistance to maximal blood flow. The resistance appears significantly higher in left ITA compared to both the right ITA and venous grafts.     

Great saphenous vein stripping with preservation of sapheno-femoral confluence: hemodynamic and clinical results

BACKGROUND: Radiofrequency and laser vein treatment, which entail preservation of the saphenous confluence, have called into question the dogma of ligation of all tributaries at the sapheno-femoral confluence (SFC), so called "crossectomy". Nevertheless, crossectomy is still done when saphenous vein stripping is chosen for varicose vein treatment. The purpose of this study was to evaluate results after stripping procedures in which the SFC was preserved. METHODS: This was a retrospective cohort study for which limbs treated for varicose veins by surgical stripping of the great saphenous vein and preservation of the SFC were studied. All limbs had a preoperative duplex examination and showed SFC and truncal incompetence of the great saphenous vein. Periodic postoperative standing duplex ultrasound and clinical examinations were carried out, and results were recorded and analyzed retrospectively. RESULTS: A total of 195 lower limbs were operated on in 151 patients (128 women and 25 men) aged from 22 to 88 years (mean age 56.8). The preoperative diameter of the SFC ranged from 4.7 to 17 mm (mean 9.5 mm). The preoperative CEAP class distribution was C1 1.5%, C2 82.1%, C3 6.7%, and C4-C6 9.7%. Preoperative symptoms were present in 61.8% of cases. Postoperative thrombosis of the SFC was observed in one case with an extension to the deep femoral vein and pulmonary embolization at 1 month. Recovery was complete. At a mean of 24.4 months postoperatively (median 27.3 months, range 8 to 34.8), persistent SFC reflux was observed in only two cases (1.8%) and a SFC neovascularization in one case (0.9%). Recurrence of varicose veins appeared in seven cases (6.3%) but in conjunction with SFC reflux in only one case. Post treatment 83.9% of limbs were converted to CEAP clinical class 0 to 1 and significant symptom improvement was observed in 91.3% of cases with an aesthetic benefit in 95.5%. CONCLUSION: Preservation of the SFC during saphenous stripping gave good results with regard to hemodynamics and neovascularization on the SFC, varicose vein recurrence, improvement of symptoms, and aesthetic appearance for legs with a median follow-up of 27.3 months.     

Early and lage results of coronary revascularization with saphenous vein and internal mammary artery grafts.

Five hundred forty-seven consecutive coronary revascularizations for anginal syndromes and 72 combined with other procedures (valve replacement, myocardial resection, closure of septal rupture) were performed during a five year period beginning in January 1972. The 619 patients received 1,794 grafts; 208 had one or two internal mammary artery grafts (IMAG) into anterior coronary arteries with or without additional saphenous vein grafts (SVG), and 411 had SVGs only. A 99.5 per cent follow-up of eighteen to seventy-eight months (mean, 50 months) allows a balanced view of the merits and shortcomings of each conduit and an evaluation of long-term surgical results.Hospital mortality of 3.3 per cent (13 of 547) in revascularization alone included 9 deaths in 402 patients (2.2 per cent) with stable angina, 4 in 134 (3.0 per cent) with unstable angina, and 5 in 11 (45.0 per cent) with cardiogenic shock. Mortality and morbidity were similar with or without IMAGs. IMAG and SVG flows measured at operation were comparable, but one year patency was 97 per cent and 86 per cent, respectively (p < 0.05). Late occlusion (3 per cent) or “distal thread” stenosis (2 per cent) occurred only in those with small IMAGs, especially when the coronary lesion was only moderately severe. Graft occlusion and recurrence of symptoms required reoperation in five SVG and two IMAG patients. Actuarial survival was 95 per cent at one year, 93 per cent at three years, and 92 per cent at five years. Ninety-five per cent of the survivors improved one functional class (FC) or more, and 85 per cent are asymptomatic, with a higher proportion in IMAG patients. Eighty-two per cent of those less than age sixty years resumed gainful employment. Hospital mortality was higher for those with combined procedures, especially with infarctectomy and/or closure of septal rupture. Zero mortality occurred in the last two years in those with revascularization and valve replacement, perhaps related to cold cardioplegic myocardial protection.Coronary revascularization provides excellent long-term functional results. Survival in the entire group, including patients with unstable angina and those with cardiogenic shock, is significantly better than survival of patients with stable angina recently reported by the Veterans Administration Cooperative Study. A 10 per cent better long-term patency rate with an IMAG is particularly important in muscular young individuals with stable hemodynamics. Its use is not warranted in unstable patients, in patients with combined procedures, and in patients with massive left ventricular hypertrophy.     

Late results of first myocardial revascularization in multiple vessel disease: single versus bilateral internal mammary artery with or without saphenous vein grafts.

OBJECTIVE(S): We evaluated our experience to investigate if the use of bilateral internal mammary artery (BIMA) grafting, with or without complementary saphenous vein grafts (SVGs), if compared to the use of single IMA and SVG(s), increases the quality of the results of coronary bypass grafting in patients younger than 75 years who undergo first myocardial revascularization. METHODS: From September 1986 to December 1999, 1602 patients younger than 75 years underwent first myocardial revascularization using left internal mammary (LIMA) to left anterior descending (LAD) and SVG(s) (n=576) or BIMA (one IMA on the LAD) with or without SVG(s) (n=1026). Propensity score analysis was used to select 1140 patients with the same preoperative and operative characteristics. Thirty day outcome was evaluated as well as 10-year freedom from death by any cause, cardiac death, acute myocardial infarction (AMI), AMI in a grafted area (GA), redo/PTCA, redo/PTCA in a GA, target cardiac events (death from cardiac cause, AMI in a GA, redo/PTCA in a GA), and any event. Follow-up ranged from 3.5 to 16.8 years (mean 7.3+/-4.8 years). RESULTS: Thirty day mortality was 2.8% in Group LIMA and 2.1% in Group BIMA, P n.s.; incidence of major complications was, respectively, 7.0 versus 5.4%, P n.s. Group BIMA showed better 10-year freedom from cardiac death (96.5+/-0.8 versus 91.3+/-1.4, P=0.0288), AMI (98.0+/-0.6 versus 94.3+/-1.2, P=0.0180), AMI in a GA (98.4+/-0.6 versus 94.7+/-1.1, P=0.0057) and target cardiac events (93.9+/-1.1 versus 86.3+/-1.8, P=0.0388). Cox analysis confirmed that LIMA+SV(s) was an independent risk factor from lower freedom from cardiac death, AMI, AMI in a GA and cardiac events. CONCLUSIONS: As freedom from cardiac events is a main target of any revascularization procedure, we think that, when a patient undergoes a first coronary surgery and is younger than 75 years, BIMA grafting should not be denied, especially if his life expectancy is higher than 10 years.     

In situ saphenous vein bypass: technical aspects and results

A consecutive series of 113 non-reversed saphenous vein grafts is presented to illustrate the technique of the procedure, modifications necessary to overcome its disadvantages and the results obtainable using such methods. The grafts were performed between January 1986 and January 1989. During this period vein utilization rate rose to more than 90%. Eighty-one procedures were performed for limb salvage (mean preoperative ankle pressure index: 0.32 +/- 0.16). Cumulative patency at 30 months was 88% (+/- 4%) for the 81 limb salvage procedures and 89% (+/- 3%) for the total 113 grafts in the series. Twelve grafts permanently failed. No graft has failed after 2 months. Amputation was avoided in 88% of limb salvage procedures. Operative mortality was 4.4%, the average age of those dying being 77 years. Fifty-three in situ grafts were followed prospectively after accurate mapping of their valve lysis was performed during surgery. Patterns of valve lysis and technical aspects related to the performance of in situ grafts will be presented.     

In situ saphenous vein bypass grafts for limb salvage: A current fad or a viable alternative to reversed vein bypass grafts?

Revascularization of the lower extremity using the in situ saphenous vein bypass graft has resurfaced as a clinical alternative to reversal of the saphenous vein. Early patency rates have been excellent, however, concern has been raised about the durability of the in situ technique. Our total experience with this technique has been reviewed to evaluate its effectiveness on a teaching vascular service. Seventy-six limbs in 71 patients were revascularized using the in situ technique. The distal anastomosis was created at the below-the-knee popliteal level in 26 limbs and at the infrapopliteal level in 50 limbs. Operative assessment of the vein quality showed 42 percent to be phlebitic or less than 4 mm in diameter. Hospital mortality was 0 and late mortality was 8 percent. Cumulative life table analysis showed the graft patency rate to be 89 percent 1 month postoperatively, 82 percent at 1 year, 77 percent at 2 years, and 72 percent up to 4 year postoperatively. Patency was independent of runoff to the pedal arch and the level of the distal anastomosis. Limb salvage at 4 years was 83 percent for distal popliteal grafts and 79 percent for infrapopliteal reconstructions. Our results indicate that the long-term durability of the in situ saphenous vein graft is excellent despite suboptimal veins and poor runoff. When performed properly, it is the preferred technique for arterial reconstruction below the knee joint.