Domingos Souza

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.

Does Periadventitial Fat-Derived Nitric Oxide Play a Role in Improved Saphenous Vein Graft Patency in Patients Undergoing Coronary Artery Bypass Surgery?

Background/Aims: The saphenous vein is commonly used for coronary artery bypass surgery but its patency is poor. Vascular damage occurs during conventional surgery. However, patency improves when the graft is harvested with minimal surgical trauma, partly due to preservation of vascular endothelial nitric oxide synthase (eNOS) and tissue sources of nitric oxide (NO), a factor possessing both dilatory and anti-proliferative properties. Apart from these grafts exhibiting an intact luminal endothelium they are harvested complete with a surrounding cushion of tissue, much of which is fat. Methods: Immunostaining for eNOS was performed on vein graft sections and reverse-transcriptase polymerase chain reaction and Western blotting were used to identify eNOS mRNA and protein. NO synthase activity was measured using the citrulline assay. Results: Immunohistochemistry identified eNOS staining of vein graft segments, including dense staining of the cushion of perivascular fat and associated structures surrounding the vein. eNOS protein was confirmed in both the vein and surrounding fat by Western blot analysis. Using the citrulline assay, the perivascular fat and underlying vein possessed comparable NO synthase activity. Conclusions: Our observations suggest that perivascular fat-derived NO plays a beneficial role in saphenous veins harvested atraumatically and used as grafts in patients undergoing coronary artery bypass surgery.

The no-touch saphenous vein for coronary artery bypass grafting maintains a patency, after 16 years, comparable to the left internal thoracic artery : a randomized trial

OBJECTIVES This study investigates whether the no-touch (NT) vein graft, at a mean time of 16 years, maintains a significantly higher patency rate than conventional (C) vein grafts and still has patency comparable to that of the left internal thoracic artery (LITA). METHODS A total of 156 patients accepted for coronary artery bypass grafting were randomly allocated to 1 of 3 groups. In the C group, the saphenous vein (SV) was stripped and distended. In the intermediate group, the SV was stripped but not distended. In the NT group, the SV was neither stripped nor distended, but rather harvested with a fat pedicle. This study is an angiographic follow-up of the C and NT groups, at a mean time of 16 years postoperatively. RESULTS Fifty-four patients were included (C group = 27; NT group = 27). In all, 72 and 75 vein grafts were completed in groups C and NT, respectively. Crude SV graft patency was 64% in the C group versus 83% in the NT group (P = .03), which was similar to the patency of the LITA (88%). The harvesting technique had a major impact on the patency with a hazard ratio for occlusion of 1.83 for the C group (P = .04). CONCLUSIONS Harvesting the SV with the NT technique conferred, at a mean time of 16 years, a significantly higher patency than the conventional technique that was still comparable to that of the LITA.

Hypothesis: A potential role for the vasa vasorum in the maintenance of vein graft patency

Autologous saphenous vein is the most commonly used conduit for coronary artery bypass surgery with more than 50% grafts occluding within 10 years. In conventional preparation the vein undergoes considerable surgical trauma with damage to the outer layers during harvesting. Within these regions are situated the vasa vasorum and small vessels providing oxygen and nutrients to the vessel wall. Certain vasa vasorum terminate in the vessel lumen where it is suggested that they have a physiological role. Preservation of the vasa vasorum of saphenous veins used as bypass conduits may play an important role in the maintenance of graft patency.

The "no-touch" harvesting technique for vein grafts in coronary artery bypass surgery preserves an intact vasa vasorum.

OBJECTIVES Our objective was to evaluate the impact of vein graft harvesting technique on structure and function of vasa vasorum. METHODS Paired segments of great saphenous veins harvested either with conventional harvesting technique or no-touch technique were obtained from 9 consecutive patients undergoing coronary artery bypass grafting. Quantitative measurements, using immunohistochemistry and morphometry, were performed. Ultrastructural analyses of vasa vasorum were performed with electron microscopy. Video footage of superficial vasa vasorum in an implanted saphenous vein graft harvested with the no-touch technique was captured during a coronary bypass operation and is presented for online viewing. RESULTS The total area of vasa vasorum in vein grafts harvested with the conventional technique was significantly reduced both in the media (P = .007) and in the adventitia (P = .014) compared with vein grafts harvested with the no-touch technique. Ultrastructural findings indicated that the no-touch technique preserved an intact vasa vasorum whereas the conventional technique did not. Video footage showed retrograde flow in the vasa vasorum in vein graft harvested with the no-touch technique. CONCLUSIONS These findings show that the no-touch technique for saphenous vein graft harvesting for coronary bypass grafting preserves an intact vasa vasorum. This could represent one of the mechanisms underlying the improved patency of saphenous vein grafts harvested with this technique.

The No-Touch Saphenous Vein as the Preferred Second Conduit for Coronary Artery Bypass Grafting

BACKGROUND Injury incurred while saphenous veins are being obtained results in poor graft patency and impairs the results of coronary artery bypass grafting. A novel method of obtaining veins, the no-touch technique, has shown improved long-term saphenous vein graft patency. METHODS This randomized trial included 108 patients undergoing coronary artery bypass grafting and compared the patency of no-touch saphenous vein with that of radial artery grafts. Each patient was assigned to receive one no-touch saphenous vein and one radial artery graft to either the left or the right coronary territory to complement the left internal thoracic artery. RESULTS Angiography was performed in 99 patients (92%) at a mean of 36 months postoperatively. Graft and grafted coronary artery patency was evaluated. The patency of grafts for no-touch saphenous vein and radial artery was 94% versus 82% (p = 0.01), respectively. The patency of coronary arteries grafted with no-touch saphenous vein and radial artery grafts was 95% versus 84% (p = 0.005), respectively. Eighty-nine of 96 (93%) left internal thoracic artery grafts were patent. CONCLUSIONS No-touch saphenous vein grafts showed a significantly higher patency rate than the radial artery grafts and the patency was comparable to the patency for left internal thoracic artery grafts. This highlights the improvement in saphenous vein graft quality with the no-touch technique and increases the number of situations in which saphenous veins may be preferable to radial artery grafts as conduits in coronary artery bypass grafting.

Surgical trauma and vein graft failure: further evidence for a role of ET-1 in graft occlusion.

The saphenous vein (SV) is the most commonly used conduit for coronary artery bypass surgery. However, using traditional techniques, the occlusion rate for the SV is high, with over 50% of grafts failing within 10 years. In conventional coronary artery bypass surgery the SV is exposed to considerable damage during preparation for grafting. Recently, an increased graft patency has been described using a ‘no-touch’ technique, whereby the vein is prepared with minimal vascular trauma. There is evidence that the success of this form of coronary artery bypass surgery is a result, at least in part, of the retention of tissue-derived nitric oxide. We have examined the effects of conventional SV harvesting on vessel morphology, cell proliferation, endothelin-1 and its receptors. Considerable damage was observed in veins prepared using conventional surgery compared to ‘no-touch’ veins. The vessel wall exhibited evidence of surgical trauma, with regions of denudation of the luminal endothelium caused by distension. Endothelin-1 and endothelin-A receptors were present at subintimal regions of conventional SV segments where proliferating cells were identified. Endothelial endothelin-B receptors were also revealed that were absent at areas of distension-induced damage to the endothelium. These results suggest that endothelin-1 plays a role in vein graft failure, predominantly via the endothelin-A receptor.

Prognostic Factors for the Survival of Surgically Treated Patients for Non-Small Cell Lung Cancer

The survival and outcome rates of 284 patients who underwent surgical treatment for non-small cell lung cancer were assessed retrospectively. Resectability rate was 94.1%, hospital mortality 3.9% (n=11) and the mortality rates in patients who underwent pneumonectomy or lobectomy were 8.9% and 0.6%, respectively. The overall 5-year survival was 43.6%. Female gender, earlier stages of disease and a complete resection were strongly predictive for a long-term survival. Women in stage IA disease had a 5-year survival rate of 92.7%. The 5-year survival rate for patients in stages IIIA and N2 disease who underwent a complete resection was 21.9%, and 9% for those who did not undergo a complete resection. It is concluded that the best surgical results were observed in women who were operated on at an early stage of disease. A complete resection also contributed to a better outcome, even for patients in stage IIIA and N2 disease.

The Vasa Vasorum and Associated Endothelial Nitric Oxide Synthase is More Important for Saphenous Vein Than Arterial Bypass Grafts

No-touch (NT) saphenous vein (SV) grafts are superior to SVs harvested by the conventional technique (CT), with a patency comparable with the internal thoracic artery (ITA). Preservation of the vasa vasorum is implicated in the success of NT harvesting. We compared the vasa vasorum and endothelial nitric oxide synthase (eNOS) in NT SV with ITA and radial artery (RA) grafts. Skeletonized SV (SSV) was also analyzed. The NT SV had a higher number and larger vasa vasorum compared with ITA (P = .0001) and RA (P = .0004) that correlated with eNOS protein. Activity of eNOS in SSV grafts was significantly lower than NT SV grafts (P = 004). Since a high proportion of the vasa vasorum are removed in SSV using the CT, we suggest that preservation of the vasa vasorum and eNOS-derived NO contributes to the high patency for NT as compared with SSV grafts.

No touch vein harvesting technique for CABG improves the long-term clinical outcome.

Objectives. To investigate the long-term clinical outcome, averaging 8.5 years, of two saphenous vein harvesting techniques for CABG; no touch (NT) versus conventional (C). Design. In a randomized study, 49/52 in group NT and 44/52 in group conventional were evaluated for reangina, myocardial infarction, new revascularization, functional class, risk factors and medical treatment. The vein grafts and the native coronary arteries were correlated to the occurrence of reangina. Results. There were significantly more patients free from angina and in NYHA class I (67.3 versus 43.2%; p =0.02) in group NT compared to group C. No cardiac death was found in group NT versus three in group C. There were trends towards fewer patients with cardiac death or myocardial infarction (3.8 vs. 13.4%; p =0.16), more patients free from angina (75.5 vs. 63.6%; p =0.26) and fewer patients with graft occlusion (24.3 vs. 43.2% (p =0.14) in group NT. Conclusions. The results of the NT-technique are encouraging with no cardiac deaths, significantly more asymptomatic patients and a trend towards impact on hard clinical endpoints compared to the conventional technique.