Purely internal thoracic artery grafts: outcomes

BACKGROUND: Most of our patients with coronary artery disease have undergone bypass exclusively with purely internal thoracic artery grafts (PITA). Our goal has been to lengthen the time a patient benefits from coronary bypass operations. The present report describes an 8.5-year study of outcomes including mortality and the need for reintervention in patients who have undergone bypass with PITA. METHODS: We studied 897 patients who underwent PITA with a total of 3,784 internal thoracic artery (ITA) grafts (4.2 grafts per patient). Connecting ITA to ITA along with sequential anastomosis made the procedure possible. RESULTS: Early mortality for the group was 2.3%. Freedom from death was 86% and freedom from reintervention was 94% at 5 years after the operation. CONCLUSIONS: The acceptable early and late mortality and the 94% freedom from reintervention as long as 8.5 years after operation in this group of patients inspire us to continue choosing PITA for patients with three-vessel coronary artery disease.     

Fifteen-year follow-up for double internal thoracic artery grafts

The internal mammary artery (IMA) is the conduit of choice for myocardial revascularization. From 1972 to 1989, 586 patients received bilateral IMA and supplemental vein grafts. There were 506 men (86%) and 79 women (14%) with a mean age of 55.5 years (range 32-77 years). Unstable angina was present in 138 patients (24%), insulin-requiring diabetes mellitus in 83 (14%) and previous myocardial infarction (MI) in 25 (4%). Preoperative angiography demonstrated triple-vessel disease in 286 patients (49%) and double-vessel disease in the remaining 300 patients (51%). Left main coronary artery disease (stenosis greater than or equal to 50%) was present in 53 (9%). The mean left ventricular score was 7.4 with a range of 5 to 20. The mean number of grafts performed was 3.4 per patient. Hospital mortality was 3.6% (21 patients). Follow-up was done through direct patient contact, via the patient's physician or by telephone contact with the patient themselves or surviving family members. Follow-up was complete in 518 hospital survivors and ranged from 1 month to 17.5 years with a cumulative follow-up of 911 patient years. At 10 and 15 years, respectively, the actuarial freedom from MI was 78% and 72% and freedom from reoperation was 93% and 86%. Actuarial survival at 10 and 15 years was 85% and 70%, respectively. This longitudinal analysis demonstrates that bilateral IMA grafting has a low operative risk. The data suggest that utilization of two IMA grafts yield excellent freedom from recurrent symptoms and provides excellent long-term survival.     

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.     

Coronary revascularization with bilateral internal thoracic artery grafts]

Thirty-two patients underwent coronary revascularization with bilateral internal thoracic artery (ITA) grafts. Each patient received 2.7 grafts in average including double ITA grafts. Seventeen patients had the right ITAs as free grafts. The other sixteen were treated with 13 autologous veins and 9 right gastroepiploic arteries in addition. Fifty-five grafts out of 56 (98.2%) were proved to be patent at the time of hospital discharge. The postoperative morbidity included three reoperations for bleeding and one perioperative inferior myocardial infarction. One patient died of colon perforation after surgery and another died of cerebral infarction late after surgery. These results exhibited that coronary artery bypass grafting with bilateral ITA grafts had relatively low risks and could contribute to complete revascularization in patients with diseased coronary arteries.     

Multivessel coronary revascularization with bilateral internal thoracic artery grafts

Sixteen patients underwent coronary revascularization with bilateral internal thoracic artery (ITA) grafts between 1988 and 1989 at the Okayama University Hospital. A total 39 coronary grafts were performed, being an average of 2.4 grafts per patient. Each patient received bilateral ITA grafts, and in 5 patients an additional 7 grafts were constructed with 5 autologous veins and 2 gastroepiloic arteries. The right ITA was grafted as a free graft in 4 patients. The ITA graft patency rate was 96.8 per cent (31/32) at the time of hospital discharge. The postoperative morbidity included one reoperation for bleeding and one myocardial infarction. Coronary artery bypass grafting with bilateral ITA grafts can be safely performed and its application facilitates complete revascularization with arterial grafts.     

The bicruciate-retaining TKA: Two is better than one

Bicruciate-retaining total knee arthroplasty (TKA), which retains both the anterior and posterior cruciate ligaments, serves as an alternative to the traditional TKA procedure. This article highlights the relevant clinical investigations using the bicruciate-retaining TKA and their findings. Despite the difficulty of ensuring the structural integrity of the prosthesis, the bicruciate-retaining TKA can yield improved patient outcomes such as range of motion, kinematics, and even the survivorship of the implant. When possible, the bicruciate-retaining TKA can and should be considered as a viable option to treat end-stage arthritis of the knee.     

Hospital outcome after aorta-radial versus internal thoracic artery-radial artery grafts

BACKGROUND: We researched our data to determine whether use of radial artery (RA) led to similar hospital morbidity as use of pedicled internal thoracic artery (ITA) with vein grafts. We also investigated if use of RA, different RA operative techniques, or number of inflow grafts were predictors for hospital outcome. METHOD: Retrospectively the hospital outcome of the first 512 patients with RAs (RA group) was compared with 108 matched patients with left ITA (LITA) and vein grafts (LITA control group). Two subgroups of RA operative techniques were further analyzed: 327 patients with RA directly from aorta (aorta-RA group), and 185 patients with RA from ITA, as a composite graft, (ITA-RA group). RESULTS: Hospital outcome of the RA group was similar to that of the LITA control group. When all ischemic events (IE) were grouped together, univariate analysis showed that aorta-RA group resulted in less IE than the ITA-RA group (2.1% versus 5.9%, respectively, p = 0.025). Number of inflow grafts did not influence IE. Multivariate analysis, however, did not show that technique of proximal RA anastomosis or number of inflow grafts were predictors for IE. CONCLUSIONS: Hospital outcome after the use of the RA is similar to that of LITA with vein grafts. Univariate analysis shows less IE after direct aorta-RA anastomoses, but multivariate analysis did not show that technique of proximal RA anastomosis and number of inflow grafts are important predictors for hospital outcome.     

Assessment of left internal thoracic artery grafts by atrial pacing

The flow reactivity of a left internal thoracic artery graft (LITAG) in response to atrial pacing was evaluated in 14 patients who underwent coronary artery bypass grafting (CABG) with LITAG to left anterior descending artery (LAD). Systolic peak velocity and diastolic peak velocity were recorded using a duplex scanner of 7.5 MHz, and flow volumes in each phase and flow ratio were calculated. The external temporary atrial pacing was used to increase heart rates 25 and 50%. Diastolic peak velocity and flow volume increased predominantly on both pacing rates. In contrast, systolic peak velocity decreased when heart rate was raised 50%, and there was no significant difference between the pacing modes in systolic flow volumes. As a result, flow ratio increased predominantly on both pacing rates. Based on the present studies, there may be some advantages with atrial pacing to increase the LITAG flow in response to the myocardial oxygen demand.     

Assessment of internal thoracic artery grafts using duplex scanning]

In an effort to develop a noninvasive method to evaluate flow characteristics of the internal thoracic artery grafts (ITAG) after coronary artery bypass grafting, we performed duplex scanning of ITAGs of 51 patients who underwent bypass grafting. The ITAG was visualized with a duplex scanner of 7.5 MHz through the first or second left intercostal space. The visualization of the ITAG was adequate to make reliable measurements in 47 patients (92.2%). The diameter of the vessel, systolic peak velocity, and diastolic peak velocity were recorded, and systolic flow volume, diastolic flow volume, velocity ratio, flow volume ratio, and diastolic flow volume fraction were calculated. The velocity ratio, flow volume ratio, and diastolic flow volume fraction were markedly higher in the unstenotic subjects than in the stenotic subjects. In the group in which severe LAD stenosis were recognized preoperatively, both systolic and diastolic flow volumes were increased compared with moderately stenotic group. No differences in flow characteristics could be demonstrated between the subjects with old anterior myocardial infarction and without it. In 10 patients in whom flow pattern was abnormal or not identified, angiography revealed graft stenosis or predominant native coronary arterial flow. Duplex scanning is thought to be a reliable, sensitive, and noninvasive technique for the assessment of the ITAG.     

Free flow capacity of skeletonized versus pedicled internal thoracic artery grafts in coronary artery bypass grafts.

OBJECTIVE: The internal thoracic artery (ITA) is the ideal conduit for coronary artery bypass grafting (CABG). The skeletonization technique of this arterial conduit has been proposed to reduce chest wall trauma, increase graft length and facilitate construction of sequential anastomoses. Nevertheless, some surgeons decline this technique because of potentially increased trauma to the ITA with impairment of flow. In this investigation we compared the free flow of skeletonized with that of pedicled ITA grafts. METHODS: Two surgeons operated on 80 consecutive patients with coronary artery disease for elective CABG. In group I (n = 40), the left ITA was dissected using the skeletonization technique. In group II (n = 40), it was harvested as a pedicled graft. In 23 patients of group I both ITA's were dissected in skeletonized fashion for complete arterial revascularization. Diluted papaverine was instilled into the lumen of the ITA after distal transection of the vessel in both groups. Free flow of the ITA was registered before and 15 min after intraluminal application of diluted papaverine. Mean arterial pressure was maintained at 70 mmHg. RESULTS: Before the application of papaverine, free flow of skeletonized and pedicled ITA grafts was identical between the two groups. After treatment with papaverine maximum free flow was significantly higher in the skeletonized ITA's (group I 197.2 (+/-66.6) ml/min; group II 147.1 (+/-70.5) ml/min; P < 0.05). There was no significant difference between free flow after dilatation of the left and right ITA in group I (left 197.2 (+/-66.6) ml/min; right 198.9 (+/-61.8) ml/min). CONCLUSIONS: Preparation of the ITA with the skeletonization technique results in significantly, higher free flow capacity than in pedicled grafts. This may increase the safety of arterial revascularization by reducing the risk of ITA hypoperfusion syndrome.     

Human gastroepiploic artery has greater chymase activity than the internal thoracic artery

Objective: Recent reports have demonstrated that long-term patency of the gastroepiploic artery (GEA) in coronary artery bypass grafting (CABG) is less satisfactory compared with the internal thoracic artery (ITA). However, the reason has not been fully elucidated. Angiotensin II is known to play an important role in the development of intimal hyperplasia, we hypothesized that the GEA is different from the ITA with respect to angiotensin II-forming ability. Accordingly, we measured activities of angiotensin II-forming enzymes, angiotensin-converting enzyme (ACE) and chymase, in human GEA and ITA. Methods: Remnant of the GEAs and ITAs were obtained from 24 patients who underwent CABG in which both conduits were used simultaneously. Activities of ACE and chymase were measured by using the extract form the GEA or ITA. Sections of the GEA or ITA were immunohistochemically stained with anti-human chymase antibody. Results: The ACE activity of the GEA (0.28 ± 0.16 mU/mg protein) was greater than that of the ITA (0.18 ± 0.11, p < 0.001). The chymase activity of the GEA (11.11 ± 7.15 mU/mg protein) was also greater than that in the ITA (7.13 ± 4.89, p < 0.001). The density of chymase-positive cells in the GEA (3.8 ± 4.2 cells/mm²) was greater than that in the ITA (1.1 ± 1.2, p < 0.01). Conclusion: Activities of both ACE and chymase were significantly greater in the GEA compared with the ITA. The GEA may be different from the ITA with respect to potential ability of angiotensin II-formation.     

Bilateral skeletonized internal thoracic artery grafts in patients with diabetes mellitus

OBJECTIVE: Increased risk of deep sternal infections has prohibited routine bilateral internal thoracic artery grafting in diabetic patients. The technique for harvesting the skeletonized internal thoracic artery provides the potential to minimize this risk. The purpose of this study was to compare the outcome of bypass grafting with bilateral skeletonized internal thoracic arteries in diabetic and nondiabetic patients. METHODS: From May 1996 to April 1998, 231 consecutive diabetic and 534 nondiabetic patients underwent bilateral skeletonized internal thoracic artery grafting. Mean age was 66 years. Compared with the nondiabetic group, the diabetic group comprised more women (29% vs 18%, P =.001), had a greater prevalence of hypertension (53% vs 44%, P =.019) and congestive heart failure (20% vs 14%, P =.016), but a lower prevalence of preoperative acute myocardial infarction (26% vs 34%, P =.027). RESULTS: Operative mortality of diabetic patients was comparable with that of nondiabetic patients (3% vs 2.6%). The two groups also had similar occurrences of deep sternal infection (2.6% vs 1.7%, respectively, P =.40). Deep sternal infection was significantly more prevalent in obese, diabetic women (3/20 = 15%) than in diabetic patients without this combination of risk factors (3/211 = 1.4%, P <.0001) (odds ratio 11.1, confidence interval 2.1-59.4). Diabetic patients also had a higher incidence of stroke (3.5% vs 0.9%, P =.014). Three-year actuarial survival of diabetic patients was lower (91.3% vs 94.7%, P =.083). CONCLUSIONS: Bilateral skeletonized internal thoracic artery grafting is a good surgical revascularization option in diabetic patients. Operative mortality and prevalence of sternal infection are comparable with those of nondiabetic patients. However, the risk of sternal infection in obese diabetic women is high, and for them we advocate the use of a single artery instead of bilateral internal thoracic arteries.     

Early vasoreactive profile of skeletonized versus pedicled internal thoracic artery grafts

BACKGROUND: No data are available on the early vasoreactive profile of skeletonized internal thoracic artery grafts. METHODS: Fifteen patients undergoing primary isolated coronary artery bypass grafting were randomly assigned to receive a skeletonized or pedicled internal thoracic artery graft. On the second postoperative day all patients were subjected to follow-up angiography and endovascular infusion of serotonin, acetylcholine, and isosorbide dinitrate. RESULTS: Internal thoracic artery grafts were widely patent in all cases. Mean diameters of the internal thoracic artery were 1.95 +/- 0.17 mm in the pedicled group and 2.26 +/- 0.40 mm in the skeletonized group. After serotonin challenge, mean internal thoracic artery diameters were reduced to 1.44 +/- 0.34 mm and 1.64 +/- 0.14 mm, respectively; acetylcholine challenge lead to a moderate degree of vasoconstriction (1.55 +/- 0.59 mm in the pedicled group and 1.84 +/- 0.15 mm in the skeletonized group). No statistically significant difference was evident between the two groups at any step. CONCLUSION: Skeletonization does not affect the early vasoreactive profile of internal thoracic artery grafts used for surgical myocardial revascularization.