The left internal thoracic artery and radial artery composite graft in off-pump coronary artery bypass grafting.

Arterial multivessel bypass grafting without extra corporeal circulation and manipulation of the ascending aorta should be a good surgical option for the treatment of coronary artery disease. An internal thoracic artery (ITA)-radial artery (RA) composite graft was used for this purpose. Between July 2000 and October 2001, we employed the LITA-RA composite graft for off-pump coronary artery bypass in 15 cases. Mean patient age was 71.3 +/- 5.8 years old. Left main trunk disease was present in six patients and triple-vessel disease in four patients. Preoperative concomitant disease was renal dysfunction in three cases, cerebrovascular disease in four and diabetes mellitus in five cases. Two patients had a so-called bad aorta. Twelve elective operations and three urgent operations were carried out for unstable angina. Two to four (mean 2.6 +/- 0.7) anastomoses were performed per patient. Complete revascularization was achieved in 12 out of 15 patients. Mean operating time was 335 +/- 53 min. Mean intraoperative blood loss was 595 +/- 375 ml and nine patients underwent the operation without blood transfusion. There was no PMI, no brain disorder, and no death. Postoperative coronary angiography in all patients documented a good patency rate (LITA 15/15, RA 21/21, right gastroepiploic artery (RGEA) 2/2, and saphenous vein graft (SVG) 0/2). LITA-RA composite grafting in off-pump coronary artery bypass enables arterial multivessel revascularization using an aortic no touch technique. This can be done with minimum postoperative complications and without risk of cerebral infarction even in patients at high risk for extracorporeal circulation (ECC).     

Contractile effects of arginine analogues on human internal thoracic and radial arteries

OBJECTIVES: Plasma levels of endogenous guanidino-substituted analogues of L -arginine are increased in various pathologic conditions. In the present study we determined the effects of some of these compounds on basal and stimulated release of nitric oxide in human internal thoracic and radial arteries. METHODS: Rings of human internal thoracic and radial arteries were obtained from 16 multiorgan donors. The rings were suspended in organ baths for isometric recording of tension. RESULTS: N(G)-monomethyl L -arginine (10(-6) to 10(-3) mol/L) and N(G),N(G)-dimethyl L -arginine (10(-6) to 10(-3) mol/L) caused concentration- and endothelium-dependent contractions. Maximal force of contractions for N(G)-monomethyl L -arginine and N(G),N(G)-dimethyl L -arginine in the internal thoracic artery were 18.0% +/- 4.3% and 17.8% +/- 3.8%, respectively, of the contraction to 100 mmol/L KCl, and those found in the radial artery were 9.6% +/- 2.5% and 9.1% +/- 2.4%, respectively. Aminoguanidine (10(-5) to 3 x 10(-3) mol/L) and methylguanidine (10(-5) to 3 x 10(-3) mol/L) produced endothelium-independent contractions. L -Arginine (10(-3) mol/L) prevented the contractions by N(G)-monomethyl L -arginine and N(G),N(G)-dimethyl L -arginine but did not change contractions induced by aminoguanidine and methylguanidine. N(G)-monomethyl L -arginine and N(G),N(G)-dimethyl L -arginine inhibited, in a concentration-dependent manner, the endothelium-dependent relaxation to acetylcholine in the internal thoracic artery and had little attenuating effect in the radial artery; aminoguanidine and methylguanidine were without effect. CONCLUSIONS: The results suggest that the contractions induced by N(G)-monomethyl L -arginine and N(G),N(G)-dimethyl L -arginine are due to inhibition of both basal and stimulated nitric oxide production, whereas aminoguanidine and methylguanidine do not affect the synthesis of nitric oxide. An increase in the plasma concentration of N(G)-monomethyl L -arginine and N(G),N(G)-dimethyl L -arginine is likely to represent a risk factor for abnormal vasomotor tone in conduit arteries used as coronary grafts.     

Midterm results of complete arterial revascularization in more than 1,000 patients using an internal thoracic artery/radial artery T graft

OBJECTIVE: To report the authors' 7-year experience with the internal thoracic artery/radial artery (ITA/RA) T graft as the only conduits for myocardial revascularization in two- and three-vessel disease. SUMMARY BACKGROUND DATA: One and two arterial conduits provide increasing survival benefit for coronary grafting and reduce the need for reintervention. Exclusive use of arterial conduits may provide further benefit. METHODS: From October 1993 to November 2000, 1,020 patients underwent complete arterial revascularization with the ITA/RA T graft. The authors focus on the 909 having initial bypass, with a mean age of 60 and 20% age 70 or older. The incidence of triple-vessel disease was 73%, female gender 28%, diabetes mellitus 27%, peripheral vascular disease 11%, cerebrovascular disease 10%, and chronic obstructive pulmonary disease 6%; ejection fraction was less than 35% in 11%. Perioperative data were collected prospectively. Follow-up information was obtained at a mean of 35.4 months (range 1-88) and was 95% complete. RESULTS: There were seven (0.08%) deaths within 30 days of surgery. The incidence of perioperative infarction was 3.3%, low cardiac output 2.7%, stroke 2.2%, reoperation for bleeding 3.8%, and deep sternal infection 0.8%. The actuarial survival rate was 90% at 5 years, freedom from infarction was 94%, freedom from catheterization was 83%, and freedom from reintervention (angioplasty or reoperation) was 93%. CONCLUSION: The ITA/RA T graft for complete arterial revascularization is associated with a low rate of perioperative death and complications and 5-year survival and freedom from reintervention values consistent with other revascularization strategies.     

A new technique for the old arterial graft: internal thoracic artery

The internal thoracic artery (ITA) is the gold-standard conduit for coronary artery bypass surgery. It stays patent well in the long-term period, and this evidence is directly related to the superior later outcome in terms of longevity. Coronary artery bypass grafting with multiarterial grafts can be performed safely, and better long-term result can be expected with the use of arterial conduits, especially ITA. We describe a simple and practical technique for the left ITA grafting by dividing the ITA graft and using its proximal and distal parts in situ for the distal left anterior descending (LAD) artery and the obtuse marginal artery grafting.     

Off-pump awake coronary revascularization using bilateral internal thoracic arteries

Background

A new technique has been developed that permits complete arterial revascularization of the lateral and/or inferior wall of the heart using in situ bilateral internal thoracic artery grafts in awake patients. This technique, without cardiopulmonary bypass and mechanical ventilation, creates the least invasive revascularization method for the lateral and/or posterior wall of the heart yet described.

Methods

In 7 patients double or triple vessel coronary artery bypass grafting was performed without general anesthesia. A high thoracic epidural anesthesia was started one hour before surgery. Bilateral internal thoracic arteries were harvested and all anastomoses were performed with the off-pump technique by standard median sternotomy. Circumflex, or the right coronary artery, were anastomosed with bilateral internal thoracic arteries using a heart positioner. Six patients received double bypass grafting and one patient received triple bypass grafts (bilateral internal thoracic arteries and one radial artery).

Results

All patients remained awake throughout the whole procedure. There was no perioperative myocardial infarction or mortality. Pneumothorax was observed in three patients, but it was repaired in two. Only one patient completed the procedure with unilateral pneumothorax. There were no hemodynamic and pulmonary problems during lateral or posterior wall revascularization. Two patients required unexpected coronary endarterectomy during circumflex and right coronary artery anastomoses.

Conclusions

Complete arterial revascularization by median sternotomy using in situ bilateral internal thoracic artery grafts without general anesthesia is a feasible and safe procedure for multivessel disease. This approach gives a chance for awake revascularization of the right and/or circumflex coronary artery.     

Atherosclerosis of radial and internal thoracic arteries used in coronary bypass: atherosclerosis in arterial grafts

BACKGROUND: This study aimed to evaluate the degree and incidence of atherosclerosis in internal thoracic (ITA) and radial arteries (RA) harvested for coronary bypass grafting. MATERIALS AND METHODS: The association of major clinical events and etiological factors for atherosclerosis was investigated in 770 arterial segments obtained prospectively from 480 patients. Potential risk factors for atherosclerosis were age, gender, smoking, diabetes mellitus, peripheral vascular disease, cerebrovascular disease, chronic renal failure, hypercholesterolemia, obesity, hypertension, and a positive family history. RESULTS: Six types of histological lesions have been defined; grade III or more was present in the RA in 47 (16%) patients and in the ITA in 30 (7%). The mean grade was 1.6 +/- 0.6 in the ITA and 2.1 +/- 0.9 in the RA (p < 0.001). CONCLUSION: RA had a significantly greater prevalence of atherosclerosis than the same patients' ITA. There was a strong correlation between ITA atherosclerosis and age. The presence of calcification may lead surgeons to avoid an extra incision according to risk factors, although most of these are not predictive.     

Complete myocardial revascularization with bilateral internal thoracic artery T graft

BACKGROUND: The internal thoracic artery is widely recognized as the ideal graft for coronary artery bypass procedures. However, because of the inadequate length of the conduit, use of bilateral internal thoracic artery grafting was not suitable for complete revascularization. To overcome this limitation, the T graft was introduced in the 1990s. We decided to prospectively assess the safety of this technique. METHODS: One hundred six patients with a mean age of 51.5 years underwent complete revascularization with an internal thoracic artery T graft. Mean left ventricular ejection fraction was 0.60 (range, 0.22 to 0.85). RESULTS: No patient required reexploration for bleeding, and no patient died within 30 days after operation. On the basis of electrocardiographic changes, 3 patients sustained a perioperative myocardial infarction. One patient had a sternal wound infection. Mean follow-up was 35 months (range, 15 to 61 months). The actuarial survival rate was 99% +/- 1% at 5 years. No myocardial infarctions were reported during the follow-up. Seven patients had recurrent angina. Eighty patients (76%) underwent postoperative stress tests, and 90% had negative results. CONCLUSIONS: Complete myocardial revascularization with the T graft is a safe and reliable technique with excellent midterm results.     

Effects of cerivastatin on vascular function of human radial and left internal thoracic arteries

Background. Statins may enhance vascular function independently of effects on cholesterol. This study investigated the ability of statins to modulate the vascular recovery of arteries used as coronary bypass grafts.

Methods. Specimens of radial artery and left internal thoracic artery were obtained during coronary artery bypass grafting. The specimens were divided into vascular rings, which were incubated in the absence or presence of cerivastatin (10⁻⁶ mol/L) for either 2 or 24 hours. Using an organ bath technique, endothelial function was examined using acetylcholine (10⁻⁹ to 10⁻⁵ mol/L) after contraction by 3×10⁻⁸ mol/L of endothelin-1.

Results. Time-related endothelial dysfunction was shown in the control group of radial artery but not in the cerivastatin group: maximal endothelium-dependent vasodilation in the control and cerivastatin groups were 56.8% ± 10.2% and 65.9% ± 10.1% at 2 hours and 39.4% ± 4.7% and 68.4% ± 5.0% (p < 0.01, vs control) at 24 hours, respectively. On the other hand, in the left internal thoracic artery, those in the control and cerivastatin groups were 38.3% ± 8.2% and 45.0% ± 5.5% at 2 hours and 38.1% ± 8.2% and 56.5% ± 8.8% at 24 hours, respectively (NS).

Conclusions. In radial artery, cerivastatin significantly preserved endothelium-dependent vasodilation, which diminished with time in the control group. This could have very important implications in the clinical practice of coronary artery bypass grafting.     

A novel technique for harvesting the internal thoracic artery: linear harvesting technique using an ultrasonic surgical aspirator

The internal thoracic artery (ITA) is an important graft for coronary artery bypass grafting (CABG). Conventionally, median sternotomy or three thoracoports has been necessary to harvest ITA. We examined a linear skeletonization technique in a porcine model using an ultrasonic surgical aspirator and electrothermal bipolar tissue sealing system via a subxiphoid approach for harvesting ITA grafts. Eight healthy pigs were used for this study. Under general anesthesia, a 2-cm skin incision was made at the subxiphocostal region. After dividing the rectus abdominis muscle, the superior epigastric artery was visualized. An L-shaped retractor was used to create a working space and insert an endoscope. An ultrasonic surgical aspirator was used to dissect the ITA, and then the electrothermal bipolar tissue sealing system was used to coagulate and cut branches. All procedures were performed under endoscopic vision, allowing safe harvest of sufficient vessel length for CABG. Harvest of the ITA required 45.4±10.9?min. Histologically, the dissected ITA was undamaged and not denatured. We have developed a linear ITA skeletonization technique using only one tiny skin incision. This technique increases the effective length of ITA bypass and is less invasive than conventional ITA harvesting.     

Left internal thoracic artery composite grafting with the right internal thoracic versus radial artery in coronary artery bypass grafting

Abstract Background: The aim of this study was to compare the results of all arterial multivessel coronary artery bypass grafting using the left internal thoracic artery composite bypass graft constructed with the right internal thoracic artery or radial artery. Methods: Patients undergoing coronary artery bypass grafting with a left internal thoracic artery constructed as a composite bypass graft with either a right internal thoracic artery (n = 45; RITA group) or radial artery (n = 352; RA group) between 2003 and 2009 were included in the present study. Results: The three‐year patency rates for the RITA and RA groups were 91.8%± 4.3% and 78.6%± 3.4%, respectively (p = 0.12). Adjustments for covariates revealed the radial artery patency to be significantly inferior to the right internal thoracic artery graft (hazard ratio 4.35, 95% confidence interval 1.05 to 18.0; p = 0.043). Reintervention for target coronary artery occlusion was required in two patients in the RA group over a mean follow‐up period of 35.5 ± 21.5 months. There were 43 deaths in the entire cohort of which 20 were cardiac. After adjustment for significant variables, the risk of all‐cause mortality, cardiac death, and the composite of adverse events (death, reintervention, myocardial infarction, and stroke) were similar for the two groups (p = 0.98, 0.99, and 0.21, respectively). Conclusions: Although superior patency was observed with the right internal thoracic artery over the radial artery graft, a significant commensurate benefit in reducing the incidence of major adverse clinical outcomes was not necessarily shown. (J Card Surg 2011;26:579‐585)     

Histamine H1 and H2 receptor-mediated vasoreactivity of human internal thoracic and radial arteries

BACKGROUND: Although internal thoracic arteries (ITAs) and radial arteries (RAs) have been shown to have similar patency, RAs tend to be more vasospastic postoperatively compared with ITAs. Therefore, the purpose of this study was to examine the effect of histamine subclass 1 (H1) receptors and histamine subclass 2 (H2) receptors on vasoreactivity in human ITAs and RAs. METHODS: Vessels were obtained from coronary artery bypass grafting patients. Human arterial rings (2 mm) were mounted in tissue baths, and baseline contractility was determined. Histamine concentration response curves (10(-9)-10(-3) mol/L) were performed in the absence or presence of diphenhydramine (H1 antagonist, 10(-4) mol/L) or famotidine (H2 antagonist, 10(-4) mol/L). Comparison of curves was performed by 2-way analysis of variance with repeated measures and a Bonferroni post-t test. RESULTS: Maximal contraction to histamine was significantly greater in RA (8.3 +/- 0.8 g, n = 6) than in ITA (2.9 +/- 0.3, n = 6), (P < .05). However, there was no difference in sensitivity. Histamine-mediated responses of both RA and ITA were blocked by pre-exposure to H1 antagonist, whereas an H2 antagonist only partially inhibited RA responses while blocking most of the ITA response to histamine. CONCLUSION: These studies suggest that H1 receptors alone cause contraction in RA but not in ITA, which may have potential linkage to patency and vasospasm. Further studies are necessary to identify the exact role of H2 receptors in ITA.     

Off-pump coronary artery bypass grafting using in-situ right internal thoracic artery extended with radial artery as I-composite graft

OBJECTIVE: The purpose of this study is to assess the feasibility of utilizing the proximal right internal thoracic artery (RITA) extended with the radial artery (RA) as I-composite graft (RITA-RA graft) in off-pump coronary artery bypass grafting (OPCAB), which preserves the left internal thoracic artery to the left anterior descending artery as an isolated graft and the ascending aorta no-touch technique. METHODS: Between January 2002 and August 2006, 37 patients (aged 67.4+/-7.5 years, 86.5% male) underwent OPCAB using RITA-RA graft. All grafts were harvested in a skeletonized fashion. RITA transected at the middle portion was extended with entirely dissected RA. RITA-RA graft was anastomosed to 1 or 2 lateral artery in a parallel sequential pattern. RESULTS: The total number of distal anastomoses of RITA-RA graft was 48. The early graft patency rate was 97.9%. Five cases (13.5%) needed intra-aortic balloon pumping support during operation. Only 1 patient (2.7%) required ventilator support longer than 24 hours. The percentage of patients requiring homologous blood transfusion was 13.5%. There was no cerebrovascular accident or mediastinitis in the postoperative course. All patients were discharged from hospital. CONCLUSIONS: OPCAB using RITA-RA graft is feasible and safe. It provides satisfactory early clinical and angiographic outcomes.     

Has the in situ right internal thoracic artery been overlooked? An angiographic study of the radial artery, internal thoracic arteries and saphenous vein graft patencies in symptomatic patients.

OBJECTIVE: The right internal thoracic artery is being used infrequently despite favorable observational angiographic data. Conversely, the radial artery utilization has increased with only limited data available. The purpose of this paper is to re-evaluate the roles of the right internal thoracic artery and the radial artery grafts. METHODS: We reviewed all ischemia-directed coronary angiographic procedures from January 1996 to December 2003. A total of 219 patients had primary coronary artery bypass grafting with an internal thoracic artery and a radial artery as two of the bypass grafts. Six hundred and seventy-nine (679) graft angiograms (45 saphenous vein, 363 radial artery, 54 right internal thoracic artery and 217 left internal thoracic artery) were studied. The mean period from operation to re-angiogram was 1104+/-761 days. Angiographic outcomes were divided into groups as: (1) patent (<50% stenosis) or (2) failed (>or=50% stenosis, string sign or occluded). A generalized linear mixed model was used to analyze predictors of graft patency. Turnbull's estimates of cumulative patency were used to compare graft failure rates over time. RESULTS: A total of 632/679 (93%) grafts were patent and 47/679 (7%) grafts had failed. Empirical saphenous vein graft patency was 40/45 (89%), radial artery patency 329/363 (91%), right internal thoracic artery patency 51/54 (94%) and left internal thoracic artery patency 212/217 (98%). Pairwise comparisons of patency from the generalized linear mixed model were: LITA>RITA, OR=1.5 (P=0.5); LITA>RA, OR=5.7 (P<0.001); LITA>SV, OR=6.5 (P<0.001); RITA>RA, OR=3.9 (P=0.01); RITA>SV, OR=4.4 (P=0.01); RA>SV, OR=1.1 (P=0.7). Five-year patency estimates from the Turnbull's model were the left internal thoracic artery (95.9%), right internal thoracic artery (91.2%), the radial artery (90.6%) and the saphenous vein (81.8%). CONCLUSIONS: Consideration should be given to the routine use of both internal thoracic arteries for coronary artery bypass grafting. When additional grafts are required, there is no evidence to suggest that either the radial artery or saphenous vein is superior.     

T grafts with the right internal thoracic artery to left internal thoracic artery versus the left internal thoracic artery and radial artery: flow dynamics in the internal thoracic artery main stem.

OBJECTIVE: Complete arterial coronary artery bypass grafting with 2 grafts can be achieved even in triple vessel disease by use of a T configuration. There is still uncertainty whether the coronary flow reserve in the main stem of the left internal thoracic artery is sufficient to supply more than 1 anastomosed coronary vessel. METHODS: Between March 1996 and February 1999, 251 patients with multivessel coronary artery disease underwent complete arterial revascularization with T grafts, using either the left internal thoracic artery with the free right internal thoracic artery graft (n = 73, group I) or the left internal thoracic artery and radial artery (n = 178, group II). A mean of 4.0 (group I) versus 4.3 (group II) coronary vessels were anastomosed per patient. One week (n = 92) and 6 months (n = 28) after the operation, flow was measured in the proximal left internal thoracic artery with a Doppler guide wire. Maximum flow was determined after injection of adenosine (30 microg). RESULTS: The in-hospital mortality was 2.7% (group I) versus 2.3% (group II). At angiography (n = 142, 56.6%) the patency rate was 96.3% (group I) versus 98.2% (group II). There was no significant difference between baseline flow, maximum flow, and coronary flow reserve between the 2 groups. Coronary flow reserve increased in both groups within the first 6 postoperative months (group I, 1.85 +/- 0.31 vs 2.77 +/- 0.77, P =.0002; group II, 1.82 +/- 0.4 vs 2.53 +/- 0.73, P =.009). CONCLUSION: Both variants of T grafts allow for complete arterial revascularization with good perioperative results. The flow reserve of the proximal internal thoracic artery is adequate for multiple coronary anastomoses irrespective of the choice of the second arterial graft.     

Inferior mini-sternotomy for off-pump CABG using bilateral internal thoracic arteries

Case 1: A 72-year-old woman with effort angina underwent coronary artery bypass grafting. A preoperative coronary angiogram showed 90% stenosis in the proximal main RCA, and total occlusion in the proximal LAD, distal of which was an area well supplied by collaterals from the RCA. This patient had previously undergone right upper lobectomy due to lung cancer. With a skin incision of 8 cm, the LITA was inserted into the LAD and the RITA was inserted into the mid RCA through an inferior mini-sternotomy while the heart was beating. Case 2: A 69-year-old man with effort angina underwent CABG. A preoperative coronary angiogram showed 90% stenosis in the proximal main RCA, 75% stenosis in the PDA and total occlusion in the proximal LAD, distal of which was an area well supplied by collaterals from the RCA. With a skin incision of 11 cm, the LITA was inserted into the LAD, the RITA into the mid-RCA and the radial artery graft attached to the RITA was grafted to the PDA through an inferior mini-sternotomy while the heart was beating. In both cases, the sternum was not cut transversely in order to prevent injury to the ITAs and pseudo-joint formation. With the use of this technique, exposure of the LAD and RCA was excellent. Postoperative recovery in both patients was uneventful and postoperative angiograms revealed widely patent grafts. This technique was very useful when performing off-pump CABG using bilateral ITAs.     

Spontaneous recanalization of functionally occluded bilateral internal thoracic artery T graft

Functional occlusion of the left internal thoracic artery T graft is reported. The patient underwent triple coronary artery bypass grafting with bilateral internal thoracic artery, anastomosing in situ to the left internal thoracic artery to the left anterior descending artery, free right internal thoracic artery to the obtuse marginal and posterolateral branch of the left circumflex artery. Early angiography showed occlusion of the in situ left internal thoracic artery to the moderately stenosed left anterior descending artery and patent side arm to circumflex. However, mid-term angiography revealed restoration of the left internal thoracic artery flow. A negative exercise stress test was noted throughout the postoperative period. Flow competition with a native coronary artery may be responsible for functional occlusion of the left internal thoracic artery.     

Bilateral internal thoracic artery grafting: midterm results of composite versus in situ crossover graft

BACKGROUND: Two common techniques of bilateral internal thoracic artery grafting are the composite T graft and in situ crossover graft. The superiority of one method over the other has not yet been established. METHODS: From April 1996 to July 1999, bilateral skeletonized internal thoracic arteries were used as T grafts (composite group, n = 649) and in situ grafts (cross group, n = 351) in 1,000 consecutive patients. In the cross group, in situ right internal thoracic artery was routed anterior to the aorta across the midline for grafting to the left anterior descending artery, and the left internal thoracic artery was used for the circumflex branches. RESULTS: The two groups had comparable preoperative risk profiles. Bypass time and aortic cross-clamping time were longer in the composite group (80 +/- 38 and 67 +/- 29 minutes versus 66 +/- 43 and 55 +/- 34 minutes, respectively). Number of anastomoses per patient was similar (3.1 versus 3.2). However, more sequential anastomoses were performed in the composite group (62% versus 53%), and the gastroepiploic artery was used more often in the cross group (30% versus 19%). Thirty-day mortality was 3.9% in the composite and 2.3% in the cross group (not significant). Occurrence of postoperative complications (sternal infection, myocardial infarction, cerebrovascular accident, and bleeding) was similar. Late follow-up (2 to 56 months) showed increased return of angina (6% versus 3.1%; p = 0.046) and decreased 4-year survival (Kaplan-Meier; 86% +/- 2.7% versus 92.4% +/- 1.5%; p = 0.07) in composite patients. CONCLUSIONS: Early results of bilateral internal thoracic artery grafting with composite T graft are comparable with those of in situ grafts. However, increased angina return and decreased midterm survival led us to recommend in situ grafting whenever technically possible.