Impact of cigarette smoking on nitric oxide-sensitive and nitric oxide-insensitive soluble guanylate cyclase-mediated vascular tone regulation.

Cigarette smoking induces vascular endothelial dysfunction characterized by impaired nitric oxide (NO) bioavailability. There are two types of soluble guanylate cyclase (sGC), which is a cellular target of NO: NO-sensitive reduced form (the heme moiety with a ferrous iron) and NO-insensitive oxidized (the heme moiety with a ferric iron)/heme-free form. This study investigated the influence of cigarette smoking on NO-sensitive and NO-insensitive sGC-mediated vascular tone regulation in organ chamber experiments with isolated rat and human arteries. The rats were subcutaneously administered phosphate-buffered saline (PBS), nicotine-free cigarette smoke extract (N(-)-CSE) or nicotine-containing cigarette smoke extract (N(+)-CSE) for 4 weeks. Plasma thiobarbituric acid reactive substance (TBARS) levels were higher in the N(+)-CSE group than those in the N(-)-CSE group, and TBARS levels for these groups were higher than those for the PBS group. In the aorta and the pulmonary artery in rats administered N(-)-CSE or N(+)-CSE, acetylcholine-induced relaxation was significantly impaired compared with that in rats administered PBS; there was no significant difference in the relaxation between the N(-)-CSE and N(+)-CSE groups. However, sodium nitroprusside (NO-sensitive sGC stimulant)- and BAY 60-2770 (NO-insensitive sGC stimulant)-induced relaxations were not different among the three groups, regardless of the vessel type. In addition, in the human gastroepiploic artery, the relaxant responses to these sGC-targeting drugs were identical between nonsmokers and smokers. These findings suggest that NO-sensitive and NO-insensitive sGC-mediated vascular tone regulation functions normally even in blood vessels damaged by cigarette smoking.

The long-term patency of a gastroepiploic artery bypass graft deployed in a semiskeletonized fashion: predictors of patency.

OBJECTIVES: Whether or not using the gastroepiploic artery (GEA) is associated with improved outcomes of coronary artery bypass grafting (CABG) remains unclear. Previous research has shown that the short-term function of the GEA was strongly associated with the degree of native vessel stenosis. We assessed the association between long-term GEA patency and the degree of stenosis of the coronary artery. METHODS: We retrospectively examined 517 patients who underwent CABG with an in situ semiskeletonized GEA from January 2000 to January 2015. In this cohort, 282 (54.5%) patients underwent distant radiological evaluations for >1 year post-surgery (range 1-18 years after surgery). Quantitative coronary angiography was used to measure the degree of stenosis of the native coronary artery. Preoperative angiographic parameters include the minimal lumen diameter (MLD) and the percentage of target vessel stenosis. A multivariable stepwise Cox proportional hazards regression analysis was used to identify predictors of angiographic occlusion. RESULTS: The cumulative patency rate of the GEA was 79.3% at 10 years. A multivariable analysis showed that an MLD (hazard ratio 4.43, 95% confidence interval 3.25-6.82; P < 0.001) was an independent risk factor of GEA occlusion. A time-dependent receiver operating characteristic (ROC) curve analysis identified that an MLD >1 mm was set as the cut-off value for graft occlusion. Patients with an MLD <1 mm had a 10-year patency rate of 89.8%. CONCLUSIONS: The long-term patency of the semiskeletonized GEA was acceptable. The target vessel MLD obtained using quantitative coronary angiography was a strong predictor of patency. Good long-term patency can be expected for an MLD <1 mm.

Left Gastroepiploic Artery True Aneurysm: Case Report and Review of the Literature.

Although the aneurysm of the splenic artery represents the third most common abdominal arterial aneurysm next to the aortic and iliac aneurysms, the aneurysm of the gastroepiploic artery is extremely rare occurring at a frequency of 3-4% of all visceral arteries' aneurysms; only 17 cases have been reported in the English literature. We present the case of a 65-year-old woman with an asymptomatic visceral artery aneurysm, which was an incidental ultrasonography finding. Magnetic resonance imaging showed an arterial aneurysm close to the peripheral splenic artery with intense tortuosity of the celiac and splenic artery. Abdominal computed tomography angiography confirmed the existence of an arterial aneurysm with a diameter of 2.3 cm near the splenic hilus without identifying the involved vessel. Endoluminal treatment was considered cumbersome due to anticipated anatomic obstacles; the patient underwent an elective open surgery in which the tortuosity of the celiac and splenic arteries and the aneurysm of the left gastroepiploic artery were revealed. The aneurysm was resected after proximal and distal ligation of the gastroepiploic artery; the flow of the splenic artery was intact. Histologically, it was a true aneurysm. The patient left the hospital on the fourth postoperative day without any complication. Historically, most aneurysms of the gastroepiploic arteries have been observed in men in the sixth decade of their life and after rupture; in modern times, their early incidental apocalypse is frequent due to the widespread use of imaging studies. Diagnostic approach and preoperative planning is of paramount importance to avoid complications. Current therapeutic modalities include catheter-based techniques or laparoscopic surgery.

Conduits Used in Coronary Artery Bypass Grafting: A Review of Morphological Studies.

There is a significant variety of vascular conduits options for coronary bypass surgery. Adequate graft selection is the most important factor for the success of the intervention. To ensure durability, permeability, and bypass function, there must be a morphological similarity between the graft and the coronary artery. The objective of this review was to analyze the morphological characteristics of the grafts that are most commonly used in coronary bypass surgery and the coronary arteries that are most frequently occluded. We included clinical information regarding the characteristics that determine the behavior of the grafts and its permeability over time. Currently, the internal thoracic artery is the standard choice for bypass surgery because of the morphological characteristics of the wall that makes less prone to developing atherosclerosis and hyperplasia. The radial and right gastroepiploic arteries are the following second and third best options, respectively. The ulnar artery is the preferred choice when other conduits are not feasible.

Spasm and Reopening of the Right Gastroepiploic Artery Conduit After Coronary Artery Bypass Grafting.

BACKGROUND: The right gastroepiploic artery (RGEA) has advantages for use as an arterial conduit in coronary artery bypass graft surgery but perioperative spasm often develops. This study assessed the spasm and occlusion rates of RGEA conduits and elucidated the mechanism of reopening of occluded RGEA conduits. METHODS: Patients who received an RGEA conduit in coronary artery bypass graft surgery were studied (n = 976; 700 composite, 276 in situ, 16 free grafts; 16 received both in situ and composite grafts). Early, 1-year, and 5-year angiographies were performed in 961 patients (98.5%), 815 patients (83.5%), and 618 patients (63.3%), respectively. RESULTS: Graft spasm was demonstrated in early angiograms in 72 proximal graft trunks of 1,608 distal anastomoses (4.5%) constructed using an RGEA conduit. Early occlusion rates of composite, in situ, and free RGEA conduits were 1.1%, 2.5%, and 0%, respectively; 8.5%, 7.5%, and 21.4%, respectively, at 1 year; and 10.5%, 14.1%, and 37.5%, respectively, at 5 years. Nineteen of 23 patients who had RGEA conduit occlusions at early angiography (1 occluded anastomosis per patient) were reevaluated at 1 year, and 9 of them (47.4%) had become patent. Of 83 patients with occluded RGEA composite grafts (90 occluded RGEA conduit anastomoses) at 1-year angiography, 8 were reopened at 5 years (8.9%). Progression of native target coronary artery disease was observed in all 8 patients with reopened occluded RGEA conduits at 5 years but not in 9 patients with reopened RGEA conduits at 1 year. CONCLUSIONS: Reopening of occluded RGEA conduits occurred early and midterm postoperatively. Reopening appeared related to recovery from graft spasm, and could occur as late as midterm if associated with progression of native coronary artery disease.

Hepatic artery bridging lessens temporary ischemic injury to bile canaliculi.

AIM: To study whether transfer of blood between the right gastroepiploic artery and gastroduodenal artery could lessens the damage to bile canaliculi. METHODS: Forty male Bama miniature pigs were divided into four groups as follows: a control group, two hepatic artery ischemia groups (1 h and 2 h), and a hepatic artery bridging group. The hemodynamics of the hepatic artery in the hepatic artery bridging group was measured using color Doppler ultrasound. Morphological changes in the bile canaliculus were observed by transmission electron microscopy. Cofilin, heat shock protein 27 and F-actin expression was detected by immunohistochemistry, Western blot, and real-time polymerase chain reaction. Terminal deoxynucleotidyl transferase-mediated nick end-labeling method was used to evaluate liver injury. RESULTS: The hemodynamics was not changed in the hepatic artery bridging group. The microvilli in the bile canaliculus were impaired in the two hepatic artery ischemia groups. The down-regulation of cofilin and F-actin and up-regulation of heat shock protein 27 were observed in the two hepatic artery ischemia groups, while there were no significant differences between the control group and hepatic artery bridging group. CONCLUSION: Hepatic artery ischemia aggravates damage to bile canaliculi, and this damage can be diminished by a hepatic artery bridging duct.

Celiac artery stent placement for coronary ischemia.

INTRODUCTION: The use of endovascular technology for mesenteric interventions has become an increasingly accepted treatment modality. We present an unusual case of celiac artery stent placement for coronary ischemia. CASE DESCRIPTION: A 66-year-old male with a history most notable for coronary artery disease and coronary artery bypass grafting (CABG) x 3 utilizing left internal mammary artery to left anterior descending, radial artery to first diagonal and his right gastroepiploic artery (GEA) to posterior descending artery presented with chest pain. His work-up included a cardiac catheterization that revealed a 90% stenosis at the origin of the celiac axis. A subsequent computerized tomography angiogram confirmed this and noted moderate stenosis of his superior mesenteric artery (SMA) as well as severe inferior mesenteric artery (IMA) stenosis. The patient was taken for mesenteric angiography by vascular surgery at which time he underwent balloon-expandable stent placement in the celiac axis. The patient tolerated this procedure well and was noted to have an improvement in his symptoms postoperatively. DISCUSSION: Use of arterial conduits for CABG have proven to be superior to vein. Long-term viability of the GEA as a conduit is dependent in part on the patency of mesenteric circulation. Our findings demonstrate a viable endovascular treatment option for angina pectoris secondary to mesenteric stenosis in this unique patient population.

[Laser doppler flowmetry in esophagogastroplasty].

AIM: To present the results of laser Doppler flowmetry for assessment of gastric wall microcirculation. MATERIAL AND METHODS: The study enrolled 22 patients who underwent esophagogastroplasty. The changes in gastric microvasculature during tubular isoperistaltic transplant formation are described. Significant markers of impaired circulation in stomach transplant 5-6 cm apart from right gastroepiploic artery termination were revealed. RESULTS: Esophagogastrostomy at this level and more proximally increases the risk of anastomosis failure and cicatrical stenosis.

Which is the best graft for the right coronary artery?

Bilateral internal mammary arteries directed to the left coronaries are gaining popularity; an increasing level of evidence nowadays supports this surgical strategy. On the other hand, composite right internal mammary artery, radial artery, and gastroepiploic artery targeting high-grade stenotic lesions in the right coronary artery system may confer improved mid- and long-term patency compared to long saphenous veins. This analysis looks into the evidence comparing data of the third best available conduit for grafting the right coronary artery, and by extrapolating this report, compares total arterial revascularization vs. conventional coronary artery bypass grafting.

Denervation of gastroepiploic artery graft can reduce vasospasm.

BACKGROUND: The right gastroepiploic artery is useful as an in situ arterial graft for coronary artery bypass grafting. However, the gastroepiploic artery is more likely to cause vasospasms compared with the internal thoracic artery. We hypothesized that the cause of the spasms is the stimulation of the periarterial sympathetic nerve, because the gastroepiploic artery is classified as a muscular artery. In this study, we examined whether the spasm is reduced by removing the periarterial sympathetic nerve. METHODS: Unused parts of the gastroepiploic artery were obtained from patients who underwent coronary artery bypass grafting. The vessel was cut into 2 segments, and they were assigned to control (N+) and denervation (N-) groups. The periarterial nerve was microscopically removed from the vessels of the N- group. The vessels in both groups were investigated by hematoxylin-eosin or immunohistochemical staining, and they were stimulated by electrical field stimulation with serial frequency for isometric tension measurement. RESULTS: Histologic analyses revealed that periarterial connective tissues including neuropeptide Y were removed to expose the external elastic membrane in the N- vessel, whereas they were preserved in N+. The mean contraction by electrical field stimulation with serial frequency was consistently lower in N- than in N+ (P < .05 at 20 and 50 Hz; n = 8 each). Endothelium-dependent relaxation and contractile function of the smooth muscle were similar in both groups. CONCLUSIONS: The removal of the periarterial sympathetic nerve from the human gastroepiploic artery reduced vascular contraction, elicited by peripheral nerve stimulation, without disturbing endothelial and smooth muscle contractile functions. This reduction may contribute to the prevention of vasospasms.

Early and long-term patency of in situ skeletonized gastroepiploic artery after off-pump coronary artery bypass graft surgery.

BACKGROUND: There is at present no accurate figure for the long-term patency rate of the skeletonized gastroepiploic artery (GEA). METHODS: From January 2002 to July 2012, 956 consecutive patients underwent isolated off-pump coronary artery bypass graft (OPCABG) surgery at our institution. Of these, the 424 who underwent GEA grafting and postoperative GEA graft evaluation were the subjects of the present study. Of these 424 subjects, 155 (36.6%) underwent long-term outpatient evaluation using multidetector computed tomography angiography. RESULTS: No patient was converted from off pump to on pump surgery. Overall 30-day mortality was 0.5% (2 of 424). The overall early (4 to 21 days after surgery) patency rate of the skeletonized GEA was 98.2% (599 of 610 anastomoses). A total of 215 GEA anastomoses, including 55 sequential bypasses, were followed for long-term evaluation, of which 12, including three sequential bypasses, were found to be occluded. The overall patency rate in skeletonized GEA grafting over a mean follow-up period of 73 months was 94.4% (203 of 215). The cumulative patency rate of the skeletonized GEA was 97.8% at 30 days, 96.7% at 1 year, 96.0% at 3 years, 94.7% at 5 years, and 90.2% at 8 years after surgery. Multivariate Cox proportional hazard regression analysis showed that target vessel stenosis (p = 0.008, hazard ratio 0.086, 95% confidence interval: 0.014 to 0.53) was the only independent predictor of late graft occlusion. CONCLUSIONS: We demonstrated an accurate long-term patency rate for the skeletonized GEA superior to that for pedicled GEA or saphenous vein graft. A low-grade degree of target vessel stenosis was the only risk factor for late GEA occlusion.

A potential risk of myocardial ischemia during thoracoabdominal aortic repair after coronary artery bypass grafting using the right gastroepiploic artery.

In-situ right gastroepiploic artery (RGEA) has been used as one of the reliable conduits for coronary artery bypass grafting (CABG). We report a case of thoracoabdominal aortic aneurysm (TAAA) repair in a patient who had previous CABG using the RGEA graft. There is a great potential risk for critical myocardial ischemia when performing open repair for TAAA in those patients.

How does the right gastroepiploic artery compare with the saphenous vein for revascularization of the right coronary artery?

A best evidence topic was written according to a structured protocol. The question addressed was 'is the saphenous vein graft or right gastroepiploic artery a better conduit for revascularization of the right coronary artery?' One hundred and five articles were found using a designated search, of which 10 articles were found to represent the best available evidence to answer the clinical question. Of these 10 articles, two were reports of a randomized controlled trial and represented the highest level of evidence, whereas eight articles were retrospective observational studies. All were published between 2002 and 2012. Outcome measures varied considerably, but mostly included graft patency at varying periods of follow-up. The randomized evidence suggested that the saphenous vein had better early (6-month) and mid-term (3-year) graft patency than the right gastroepiploic artery when used for right coronary artery revascularization. The use of the saphenous vein was also found to be predictive of superior graft function using multivariate regression; however, a more recent propensity score analysis identified gastroepiploic-right coronary grafts to yield superior very long-term (>10 years) clinical outcomes. Overall, based on the best quality evidence and in view of technical limitations and flow characteristics of the right gastroepiploic artery, it appears that saphenous vein grafts may offer superior outcomes for revascularization of the right coronary artery in most cases, and should be preferentially used.

Right gastroepiploic artery is the first alternative inflow source for hepatic arterial reconstruction in living donor liver transplantation.

BACKGROUND: Sufficient arterial flow after living donor liver transplantation (LDLT) is closely related to graft survival and prevention of postoperative complications. However, some unfavorable hepatic arterial conditions in recipients preclude reconstruction, requiring alternative stumps. We have used the right gastroepiploic artery (RGEA) as a first alternative for hepatic inflow. METHODS: From January 2006 to December 2008, we performed 754 LDLTs including 28 cases of RGEA among hepatic arterial anastomoses. The arterial anastomosis was performed by an single surgeon under 859 a microscope using an end-to-end interrupted suture technique. RGEA was mobilized over 15 cm from the greater curvature of stomach and greater omentum. RESULTS: The indications for RGEA use included severe hepatic arterial injury from previous transarterial chemoembolization (n=14), need for additional arterial flow in dual-grafts LDLT (n=13), poor blood flow from the recipient hepatic artery (n=3), and arterial injury during hilar dissection (n=3). The mean diameter of the isolated RGEA was 2.0±0.2 mm (range: 1.0-2.5). Most hepatic arterial anastomoses were performed with a significant size discrepancy of more than twofold. All reconstructed hepatic arterial flowes showed good; no complication was identified during the mean follow-up period of 56 months to date. CONCLUSIONS: Using RGEA as an alternative arterial inflow is a simple, reliable procedure for situations of inadequate recipient hepatic or multiple graft arteries.

Graft selection for the right coronary artery territory in off-pump coronary artery bypass.

BACKGROUND: The ideal bypass conduit in a right coronary artery (RCA) system remains controversial. METHODS: We analyzed 121 patients who underwent off-pump coronary artery bypass with internal thoracic arteries for the left coronary artery system and either in situ a right gastroepiploic artery (RGEA; n = 66) or a saphenous vein graft (SVG; n = 55) for the RCA system were enrolled. Follow-up coronary computed tomographic angiographic data were reviewed. RESULTS: The RGEA group showed higher graft patency at 5 years, especially in high grade stenosis (≥ 80%; p = 0.009). In the SVG group, no difference was found between high grade stenosis and low grade stenosis. Freedom from adverse cardiac events at 5 years was higher in the RGEA group (p = 0.006). On multivariate analysis, low grade stenosis of RCA was predictive of graft failure (p = 0.029, hazard ratio = 10.9). CONCLUSIONS: In high grade stenosis of RCA, the RGEA group showed higher patency rate. The patency rate of SVG was not dependent on the degree of stenosis of RCA.

Angiographic predictors of 3-year patency of bypass grafts implanted on the right coronary artery system: a prospective randomized comparison of gastroepiploic artery, saphenous vein, and right internal thoracic artery grafts.

OBJECTIVE: Saphenous vein, in situ right gastroepiploic artery, and right internal thoracic artery grafts are routinely used to revascularize the right coronary artery. Little is known about the predictive value of objective preoperative angiographic parameters on midterm graft patency. METHODS: We prospectively enrolled 210 consecutive patients undergoing coronary revascularization. Revascularization of the right coronary artery was randomly performed with the saphenous vein grafts in 81 patients and the right gastroepiploic artery in 92 patients. During the same study period, 37 patients received right coronary artery revascularization with the right internal thoracic artery used in a Y-composite fashion. All patients underwent a protocol-driven coronary angiogram 3 years after surgery. Preoperative angiographic parameters included minimum lumen diameter percent stenosis measured by quantitative angiography. A graft was considered "not functional" with patency scores of 0 to 2 and "functional" with patency scores of 3 or 4. RESULTS: Angiographic follow-up was 100% complete. A significant difference in the distribution of flow patterns was observed in the 3 groups. In multivariate analysis, the use of a saphenous vein graft was associated with superior graft functionality compared with the other conduits (odds ratio, 6.1; 95% confidence interval, 2.4-15). Graft function was negatively influenced by the minimum lumen diameter (odds ratio, 0.11; confidence interval, 0.05-0.25). In the right gastroepiploic artery and right internal thoracic artery groups, the proportion of functional grafts was higher when the minimum lumen diameter was below a threshold value in the third minimum lumen diameter quartile (0.64-1.30 mm). CONCLUSIONS: Preoperative angiography predicts graft patency in the right gastroepiploic artery and right internal thoracic artery, whereas the flow pattern in saphenous vein grafts is significantly less influenced by quantitative angiographic parameters.

En-bloc free gastroepiploic artery graft provides a good long-term patency rate.

For coronary artery bypass grafting, the use of free gastroepiploic artery is unpopular because of its tendency to vasospasm. We assessed the en-bloc free gastroepiploic artery graft, which has the gastroepiploic vein anastomosed to the right atrial appendage to prevent graft spasm, and compared it to the skeletonized free gastroepiploic artery graft. A retrospective review was conducted in 57 patients who received en-bloc grafts and 29 who had skeletonized grafts. Kaplan-Meier analysis demonstrated the superiority of the en-bloc free gastroepiploic artery graft with an 80-month patency rate of 96.6% compared to 66.7% with skeletonized grafts. We selected 13 cases from each group, using propensity-score matching, and compared the long-term patency rates. Propensity-score matched analysis showed 80-month patency rates of 100% for en-bloc grafts and 60% for skeletonized grafts. Coronary artery bypass using free gastroepiploic artery grafts with venous drainage seems to provide good long-term results.

Transit-time flow characteristics of in situ right gastroepiploic arterial grafts in coronary artery bypass grafting.

OBJECTIVE: We investigated flow characteristics of right gastroepiploic arterial grafts, widely used to extend in situ arterial conduits in coronary artery bypass grafting. METHODS: Intraoperative transit-time measurements and postoperative angiographic findings were obtained for 111 patients undergoing coronary artery bypass grafting with gastroepiploic artery and bilateral internal thoracic arteries: mean, maximum, and minimum flows; pulsatility index; insufficiency rate; and differentiated index of early diastolic flow. RESULTS: Favored target for gastroepiploic artery was posterior descending artery (106 patients, 95%). Patency rates were 91.0% for gastroepiploic artery, 98.2% for left internal thoracic artery, and 97.5% for right internal thoracic artery. There were four flow profiles of gastroepiploic arteries: A (systolic protruded), B (trapezoidal), C (sine waved), and D (diastolic-dominant biphasic). Functional gastroepiploic arteries showed A in 16 cases, B in 6, C in 31, and D in 48, with prevalence according to severity of stenosis in target coronary artery. Two occluded gastroepiploic arteries showed type A, and reverse or competitive flows were types A in 1, B in 1, C in 4, and D in 2. Relative to functional internal thoracic arteries, functional gastroepiploic arteries showed significantly lower minimum flow, higher insufficiency rate, and lower differentiated index of early diastolic flow. CONCLUSION: Intraoperative transit-time flow profiles of patent in situ gastroepiploic arterial grafts were classified into four types, closely associated with disease severity of target coronary artery. Patent in situ gastroepiploic arterial grafts show more regurgitant flow and lower differentiated index of early diastolic flow than in situ internal thoracic arterial grafts.

Improving patency of coronary conduits "valveless" veins and/or arterial grafts.

BACKGROUND: Veins used for coronary artery bypass operation have a well-documented limited long-term patency. Internal thoracic artery (ITA) grafts have shown exceptional "durability." Assumptions were made that other arterial conduits have similar characteristics. AIM OF THE STUDY: The purpose of this article is to compare different conduits long-term patency including saphenous veins to other available arterial conduits: inferior epigastric artery (IE), right gastroepiploic artery (RGEA), and radial artery (RA). METHODS: Recent studies have shown that radial artery bypasses have lower patency rate than saphenous veins. Flow patterns, physiological flow characteristics are reviewed including native vessel disease and area of myocardium supplied. In the case of venous bypasses, the primary culprit of failure seemed to be the quality of the vein itself and the reverse venous valves in the conduit resulting in: (a) trapping-hypertension, (b) thrombosis, (c) turbulence, (d) intimal damage, (e) mismatching in size. RESULTS: Clinical follow-up of our patients up to 8 to 11 years (average 8.9 years) have proved the superior characteristics of the so-called "good veins." In a retrospective study of 436 patients sequential, valveless veins patency was 88.6% versus 72% of reversed valvular segments (p < 0.01). Patients' survival seemed to be significantly improved if these veins were combined with ITA grafts. Patients' survival with one valveless limb HS + ITA was 78% versus HS + SV 52% (p < or = 0.0017) and HS + ITA versus HS + ITA + SV (p < 0.0057). CONCLUSION: Selective decision-making of the surgeon at the time of the operation is required to choose the best conduit to be able to perform the best operation with the best long-term result.