Total revascularization with T grafts

Comparative Analysis of Early Postoperative Period in Patients with Total Arterial Revascularization and Conventional Coronary Artery Bypass Grafting

The use of total arterial myocardial revascularization in patients with multivessel lesions of the coronary arteries has a number of advantages, namely the duration of functioning or patency of the grafts. The level of total arterial myocardial revascularization implementation in developed and developing countries remains quite low. The aim. Based on the analysis of our own experience, to determine the influence of the technique of total arterial revascularization on the frequency of complications in the early postoperative period. Materials and methods. From February 22, 2016 to December 24, 2020, 390 consecutive patients were operated at the Ukrainian Children’s Cardiac Center. The patients were divided into two groups: participants of the group I underwent total arterial myocardial revascularization, and those includedin the group II underwent conventional coronary artery bypass grafting (CABG). The inclusion criteria were: ischemic heart disease, stable angina or exertional angina, multivascular coronary artery disease, absence of valvular pathology. Results. There was zero 30-day mortality in both groups. The frequency of postoperative bleeding was higher in group II and amounted to 1.6%. Surgical wound complications (infection) were also more common in the group II: 1.2% versus 0.69% (p=0.906) in the group I. Similarly, laboratory parameters such as the level of creatine kinase-MB were almost identical. Conclusions. Total arterial myocardial revascularization is a safe method with good immediate results. The frequency of complications in total arterial myocardial revascularizationdoes not differ from that in conventional CABG. For a wider application of the total arterial myocardial revascularization,it is necessary to continue toconduct studies of the remote postoperative period.

Late Outcomes of In Situ Versus Composite Bilateral Internal Thoracic Artery Revascularization

BACKGROUND

We compared 2 configurations for revascularization of the internal thoracic arteries to the anterior and lateral walls. In the "in situ" configuration, an in situ right internal thoracic artery supplies the left anterior descending territory, and an in situ left internal thoracic artery is grafted to the left circumflex territory. In the "composite" configuration, an in situ left internal thoracic artery is grafted to the left anterior descending artery and a free right internal thoracic artery is attached end-to-side to the left internal thoracic artery and supplies the lateral wall.

METHODS

We compared outcomes of all the patients treated in our center by the described strategies during 1996 through 2011.

RESULTS

Of 2951 patients, 1220 underwent composite grafting and 1731 underwent in situ grafting; the median follow-up was 15.1 years (interquartile range, 11.2-18.6 years). Early mortality (2.2% vs 2.0%, P = .787) and other early adverse outcomes did not differ significantly between the groups. Long-term (15-year) survival was marginally significant in favor of the in situ group (53.5% vs 49.5%, P = .05); this difference disappeared after 20 years. Configuration strategy was not a predictor for better 15-year survival in multivariable analysis (hazard ratio, 0.97; 95% confidence interval, 0.85-1.09; P = .568). An additional analysis compared matched groups of 995 patients each who underwent the 2 configuration strategies and found no differences in early outcome or late survival between the groups.

CONCLUSIONS

This study demonstrated the safety and effectiveness of 2 strategies for bilateral internal thoracic artery revascularization to the left side, with comparable early outcomes and long-term survival.

A simple-to-use nomogram to predict long term survival of patients undergoing coronary artery bypass grafting (CABG) using bilateral internal thoracic artery grafting technique

BACKGROUND

Several risk scores have been created to predict long term mortality after coronary artery bypass grafting (CABG). Several studies demonstrated a reduction in long-term mortality following bilateral internal thoracic arteries (BITA) compared to single internal thoracic artery. However, these prediction models usually referred to long term survival as survival of up to 5 years. Moreover, none of these models were built specifically for operation incorporating BITA grafting.

METHODS

A historical cohort study of all patients who underwent isolated BITA grafting between 1996 and 2011 at Tel-Aviv Sourasky medical center, a tertiary referral university affiliated medical center with a 24-bed cardio-thoracic surgery department. Study population (N = 2,935) was randomly divided into 2 groups: learning group which was used to build the prediction model and validation group. Cox regression was used to predict death using pre-procedural risk factors (demographic data, patient comorbidities, cardiac characteristics and patient's status). The accuracy (discrimination and calibration) of the prediction model was evaluated.

METHODS AND FINDINGS

The learning (1,468 patients) and validation (1,467 patients) groups had similar preoperative characteristics and similar survival. Older age, diabetes mellitus, chronic obstructive lung disease, congestive heart failure, chronic renal failure, old MI, ejection fraction ≤30%, pre-operative use of intra-aortic balloon, and peripheral vascular disease, were significant predictors of mortality and were used to build the prediction model. The area under the ROC curves for 5, 10, and 15-year survival ranged between 0.742 and 0.762 for the learning group and between 0.766 and 0.770 for the validation group. The prediction model showed good calibration performance in both groups. A nomogram was built in order to introduce a simple-to-use tool for prediction of 5, 10, and 15-year survival.

CONCLUSIONS

A simple-to-use validated model can be used for a prediction of 5, 10, and 15-year mortality after CABG using the BITA grafting technique.

Composite Y Grafts From the Left Internal Mammary Artery: Current Considerations

The use of composite coronary artery bypass grafts from the left internal mammary artery (LIMA) has increased over the last 20 years. Total arterial revascularisation can be achieved with two arterial conduits and is associated with a reduced risk of stroke. However, the traditional coronary bypass graft configurations of the in situ LIMA and aorto-coronary saphenous vein grafts remain as the mainstay of coronary bypass surgery in most centres. Concerns regarding composite Y grafts relate to (1) the adequacy of a single inflow for all coronary bypass grafts; (2) the risk of compromising the LIMA flow to the left anterior descending coronary artery; (3) the effects of competitive flow on graft patency; and (4) the use of sequential coronary anastomoses. The evidence upon which these concerns are based will be discussed along with the evidence relating to the use of the various second conduit options.

Should Bilateral Internal Thoracic Artery Grafting Be Used in Patients After Recent Myocardial Infarction?

Background

Bilateral internal thoracic artery grafting (BITA) is associated with improved survival. However, surgeons do not commonly use BITA in patients after myocardial infarction (MI) because survival is good with single internal thoracic artery grafting (SITA). We aimed to compare the outcomes of BITA with those of SITA and other approaches in patients with multivessel disease after recent MI.

Methods and Results

In total, 938 patients with recent MI (<3 months) who underwent BITA between 1996 and 2011 were compared with 682 who underwent SITA. SITA patients were older and more likely to have comorbidities (diabetes mellitus, chronic obstructive pulmonary disease, chronic renal failure, peripheral vascular disease), to be female, and to have had a previous MI. Acute MI and 3‐vessel disease were more prevalent in the BITA group. Operative mortality of BITA patients was lower (3.0% versus 5.8%, P=0.01), and sternal infections and strokes were similar. Median follow‐up was 15.21 years (range: 0–21.25 years). Survival of BITA patients was better (70.3% versus 52.5%, P<0.001). Propensity score matching was used to account for differences in preoperative characteristics between groups. Overall, 551 matched pairs had similar preoperative characteristics. BITA was a predictor of better survival in the matched groups (hazard ratio: 0.679; P=0.002; Cox model). Adjusted survival of emergency BITA and SITA patients was similar (hazard ratio: 0.883; P=0.447); however, in the nonemergency group, BITA was a predictor of better survival (hazard ratio: 0.790; P=0.009; Cox model).

Conclusions

This study suggests that survival is better with BITA compared with SITA in nonemergency cases after recent MI, with proper patient selection.

On-Pump versus Off-Pump Complete Arterial Revascularization Using Bilateral Internal Mammary Arteries and the T-Graft Technique: Clinical and Angiographic Results for 3,445 Patients in 13 Years of Follow-Up

BACKGROUND

This is an investigation of complete arterial coronary artery bypass grafting (CACABG) using bilateral internal mammary arteries (IMA) and the T-graft technique either on- or off-pump as a routine approach to treat coronary artery disease.

METHODS

Between January 2000 and December 2012, 3,445 patients underwent on-pump (n = 2,216) or off-pump (n = 1,229) CACABG. A 30-day follow-up was performed prospectively, a long-term follow-up by a questionnaire, and coronary angiography in selected patients.

RESULTS

End points at 30 days were death, myocardial infarction, stroke, repeat revascularization, renal replacement, reoperation, sternal wound infection and atrial fibrillation. FitzGibbon A patency rates were 89.8 vs. 91.4% (p = 0.464) with consecutive percutaneous coronary intervention in the grafted area of 1.8 vs. 1.1% (p = 0.693) on- vs. off-pump, and no reoperation in the grafted area in both groups.

CONCLUSION

CACABG by use of skeletonized bilateral IMA with the T-graft technique performed either on- or off-pump is a safe and effective approach.

Does the surgeon's experience have an impact on outcome after total arterial revascularization with composite T-grafts? A risk factor analysis

OBJECTIVES

When composite T-grafting is performed, total arterial revascularization (TAR) can be accomplished with only two grafts. There is the belief that composite grafting poses a risk of graft failure due to its single inflow via the left internal thoracic artery (LITA). High surgical quality is essential for left internal thoracic artery preparation, T-grafting and length estimation. We investigated whether the surgeon's experience influences postoperative outcome.

METHODS

We analysed the data of 1080 consecutive patients (88% male, age: 62 ± 9 years) who underwent composite T-grafting between 1996 and 2011 in our institution. Patients were operated on either by experienced surgeons (Group A) or by surgeons early on in their career (Group B). Primary end-points were mortality, myocardial ischaemia, graft dysfunction and low cardiac output syndrome. Secondary end-points were persistent neurologic deficits (PNDs), blood transfusions and re-thoracotomy. Logistic regression analysis was performed to reveal independent risk factors for adverse outcome.

RESULTS

Patients in Group B had a lower logistic EuroSCORE (2.8 vs 2.3%; P < 0.05), longer operative times (cross-clamp time: 41 ± 11 vs 47 ± 14 min; P < 0.001) and received less anastomoses (3.2 ± 0.7 vs 3.1 ± 0.7, P = 0.005). Mortality was low in both groups (Group A 0.6% vs Group B 0.4%; P = 1.0). Myocardial ischaemia occurred in 2.3% (Group A) and 2.5% (Group B; P = 0.82). Graft dysfunction was seen in 0.6% (Group A) and 1.4% (Group B; P = 0.25). Incidence of postoperative low cardiac output syndrome was comparable (Group A 1.4% vs Group B 0.7%; P = 0.53). Both groups showed similar incidence of secondary end-points (persistent neurologic deficit: Group A 2.9 vs 3.2% in Group B; P = 0.84; re-thoracotomy: 1.6% in Group A vs 1.8% in Group B, P = 1.0). Blood transfusions were more common in Group B (P = 0.005). Less surgical experience could only be identified as an independent risk factor for blood transfusion (P = 0.001).

CONCLUSIONS

Total arterial revascularization with composite T-grafts can be performed safely by surgeons with different surgical experience. Despite differences in surgical performance parameters (e.g. operation times, blood transfusions), complication rates were extremely low, irrespective of the surgeon's operative experience. Surgeons can be introduced to these procedures in an early phase of training.

Sequential Radial Artery Grafting Three-Vessel Coronary Artery Disease

Our objective was to compare the results of revascularization by sequential radial artery (RA) grafting with a left anterior descending left internal mammary artery (LIMA)-RA t-composite grafting technique. Patients were grouped as those with proximal anastomoses performed on the ascending aorta (Group A; n = 38), and those with proximal anastomoses performed on the LIMA as t-grafts (Group T; n = 13). Neither of the two groups revealed any mortality. The average number of grafts was lower in Group T (2.23 ± 0.43 in group T and 2.85 ± 0.69 in group A, p < 0.05). The results of the control coronary artery angiographies were superior in Group A. The patency rate of the RA grafts was 96.8% in Group A. Of the 20 distal anastomoses performed with RA grafts in 8 patients from Group T, nine (45%) were found to be patent. The patency rates of RA grafts with sequential distal anastomoses were found to be better when the proximal anastomosis was performed on the ascending aorta rather than on the LIMA. In conclusion, sequential distal anastomosis of RA grafts seem to be safe and effective when proximal anastomoses are performed on the ascending aorta.

Myocardial Revascularization with Multiple Arterial Grafts

From October 1991 10 July 1994, 439 patients underwent elective or urgent coronary artery bypass grafting utilizing 2 or more arterial conduits. Age ranged from 28 to 79 years (mean, 62.3 years). Most of the patients had 3-vessel disease (301); the remaining had 2-vessel (120) or 1-vessel (18) disease. A stenosis of the left main trunk greater than or equal to 50% was present in 73 patients; in 16 cases it was a redo operation. The left ventricular ejection fraction ranged from 0.19 to 0.84 (mean, 0.53). We utilized 1110 arterial conduits (430 left internal mammary arteries, 259 right internal mammary arteries, 136 right gastroepiploic arteries, 120 inferior epigastric arteries, 165 radial arteries) together with 113 saphenous veins (2.63 arterial anastomoses per patient, ranging from 2 to 6). In 347 patients (79%) we performed a complete arterial myocardial revascularization with an average of 2.80 anastomoses per patient. Two arterial conduits were used in 245 patients, 3 in 163, 4 in 30, and 5 in 1 patient. The myocardial protection was achieved by means of intermittent antegrade warm blood cardioplegia. The mean cross-clamping time was 47.3 ± 16 minutes (range, 16 to 142 minutes). Five patients (1.1%) died in the postoperative period, none were in the operating theater. The causes of death were cardiac (2), sepsis (1), pneumonia (1) and pancreatic necrosis (1). In 7 patients (1.6%) a perioperative myocardial necrosis occurred without any hemodynamic sequelae. Out of 430 patients alive, 419 (97.4%) are asymptomatic. At the postoperative angiographic control all the arterial grafts explored showed complete patency; the midterm angiography (mean, 14 months) revealed a cumulative patency of 96% (range, 100% for the left internal thoracic artery to 94.1% for the radial artery). We conclude that on the basis of the early results the technique herein described is effective and reproducible, even if long-term follow-up is needed to confirm these data.

Myocardial Revascularization Exclusively With Bilateral Internal Thoracic Arteries in T-Graft Configuration: Effects on Late Survival

BACKGROUND

We studied long-term survival using bilateral internal thoracic artery (BITA) grafting in a T-configuration exclusively versus using single internal thoracic artery (SITA) grafting in patients with multivessel disease.

METHODS

Consecutive coronary operations performed at a single center between 1996 and 2014 were reviewed. Long-term survival among patients receiving coronary revascularization exclusively with BITA grafting in a T-configuration (n = 2,098) versus SITA grafts plus other types of conduits (saphenous vein graft [SVG] and radial artery [RA]) grafts (n = 1,659). In patients who underwent BITA grafting, the left internal thoracic artery (LITA) was grafted mainly to the left anterior descending artery, whereas the right internal thoracic artery (RITA) was used more commonly to graft the circumflex (Cx) artery and the right coronary system as T-grafts. A total of 485 pairs of patients were matched using propensity scores. Cox proportional hazard models were generated to examine the association of arterial BITA grafting with mortality.

RESULTS

Patients in the BITA group were more likely to be younger (BITA, 63.7 ± 9.1 versus SITA, 65.0 ± 9.9; p < 0.0001). At 30 days, patients who underwent BITA grafting experienced reduced unadjusted mortality (BITA, 1.2% versus SITA, 4.4%; p < 0.0001). At 10 years, patients who underwent BITA grafting experienced superior unadjusted survival (BITA, 82.6% ± 1.8% versus SITA, 76.1% ± 1.3%; p = 0.001). Cox regression analysis in the entire study cohort showed that BITA grafting was associated with improved survival (hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.58-0.87; p < 0.001). In the propensity-score-adjusted analysis, patients who underwent BITA grafting had similar in-hospital mortality (BITA, 1.6% versus SITA, 2.9%; p = 0.196). Patients who underwent BITA grafting still showed improved survival at 10 years (BITA, 81.0% ± 4.1% versus SITA, 71.8% ± 2.5%; p = 0.039).

CONCLUSIONS

This study suggests that coronary artery operations exclusively with BITA grafting in a T-configuration may be associated with better long-term survival than grafting with SITA plus other types of conduits.

Long-term outcome of revascularization with composite T-grafts: Is bilateral mammary grafting better than single mammary and radial artery grafting?

OBJECTIVE

Bilateral internal mammary artery (BIMA) grafting is associated with improved survival. However, many surgeons are reluctant to use this technique, owing to the potentially increased risk of sternal infection. The composite T-graft with radial artery (RA) attached end-to-side to the left internal mammary artery (IMA) provides complete arterial revascularization without increased risk of sternal infection. The purpose of this study is to compare outcomes of these 2 strategies.

METHODS

Patients who underwent BIMA grafting using the composite T-graft technique, between 1996 and 2010 (n = 1329), were compared with 389 patients who underwent composite grafting with a single IMA + RA during the same time period.

RESULTS

Patients undergoing single IMA grafting were older, more often women, and more likely to have diabetes, peripheral vascular disease, and COPD, and to need an emergency operation. Congestive heart failure, left main disease, and recent myocardial infarction were more prevalent with bilateral grafting. Propensity-score matching was used to account for differences between groups in preoperative patient characteristics. The 268 matched pairs had similar characteristics. The median follow-up time was 14.19 (95% confidence interval 13.43-14.95) years. Operative mortality and Kaplan-Meier 10-year survival of the 2 matched groups were similar (3.4% vs 3.7%, and 61.6% vs 64%, for the groups treated with BIMA and single IMA, respectively). Cox-adjusted survival was similar (P = .514). Age, chronic renal failure, and performance of <3 bypass grafts were independent predictors of decreased survival.

CONCLUSIONS

This study suggests that long-term outcomes of arterial revascularization with a composite T-graft constructed using left IMA and RA are not inferior to outcomes after BIMA grafting.

Multiple composite grafts (k, π or double-Y) in coronary artery surgery: a choice or a necessity?

OBJECTIVES

Composite grafts allow complete arterial revascularization with minimal aortic manipulations. The Y-T configuration supplies all distal branches adequately, whereas it is unclear whether complex composite configurations (K, Π or double-Y) are equally at rest or when challenged by maximal requirements.

METHODS

Forty-seven patients who underwent off-pump coronary artery revascularization by multiple arterial composite grafts (K, Π or double-Y) were retrospectively evaluated. Indication for this surgical option was porcelain aorta or conduit unavailability. Composite systems were evaluated by intraoperative flow measurements and perioperative transthoracic Doppler ultrasonography, 12 months later also by exercise test, sestamibi scintigraphy at rest and during induced hyperaemia and by 64-slice multidetector CT angiography.

RESULTS

A total of 141 distal anastomoses were implanted as composite grafts. Perioperative flow measurements and 12-month Doppler ultrasonography were adequate at rest. At stress test, chest pain and/or induced ECG evidence of ischaemia are found in 16 patients (39%). During dipyridamole-induced hyperaemia, single-photon emission computed tomography image revealed that mean summed stress score was 7.2 ± 5.7, summed difference score 5.3 ± 4.2 and coronary flow reserve 1.7 ± 0.2.

CONCLUSIONS

Multiple composite grafts, albeit adequate at rest, were unable to meet flow requirements during maximal hyperaemia. In daily practice, their use must be not a choice but rather a necessity in those patients without alternative options.

Optimal bypass graft design for left anterior descending and diagonal territory in multivessel coronary disease

OBJECTIVES

Coronary artery bypass grafting for multivessel disease requires an appropriate graft design to avoid the competition of flow between the graft and the native vessel in order to achieve a sufficient coronary flow and durable graft patency.

METHODS

Three-dimensional computational models of the left coronary artery were created based on the angiographic data. Three stenosis patterns of 75 and 90% combinations were created in the left anterior descending artery (LAD), the diagonal branch (Dx) and the circumflex artery (LCx). The left internal thoracic artery (LITA) was anastomosed to the LAD, and separate saphenous vein grafts (SVGs) were anastomosed to the Dx and the LCx in the 'Independent' model. The 'Sequential' model included sequential SVG anastomoses to the Dx and the LCx with a left internal thoracic artery-left anterior descending artery bypass, and Y-composite arterial grafts to LAD and Dx were created in the 'Composite' model.

RESULTS

The 'Independent' model had high reverse flow from the Dx to the LAD in systole, resulting in decreased LITA flow when Dx stenosis was mild. The 'Sequential' model also had reverse flow in diastole, resulting in additional LAD flow. The 'Composite' model distributed increased flow to the Dx when Dx stenosis was severe, resulting in decreased flow to the LAD.

CONCLUSIONS

Systematic flow evaluation is beneficial for determining the optimal bypass graft arrangement in patients with multivessel disease. Individual SVG anastomoses to the Dx and the LCx are not desirable when Dx stenosis is not severe and a Y-composite arterial graft to the LAD and the Dx is not desirable when Dx stenosis is severe.

Coronary artery bypass graft: why is the saphenous vein prone to intimal hyperplasia?

Proliferation and migration of smooth muscle cells and the resultant intimal hyperplasia cause coronary artery bypass graft failure. Both internal mammary artery and saphenous vein are the most commonly used bypass conduits. Although an internal mammary artery graft is immune to restenosis, a saphenous vein graft is prone to develop restenosis. We found significantly higher activity of phosphatase and tensin homolog (PTEN) in the smooth muscle cells of the internal mammary artery than in the saphenous vein. In this article, we critically review the pathophysiology of vein-graft failure with detailed discussion of the involvement of various factors, including PTEN, matrix metalloproteinases, and tissue inhibitor of metalloproteinases, in uncontrolled proliferation and migration of smooth muscle cells towards the lumen, and invasion of the graft conduit. We identified potential target sites that could be useful in preventing and (or) reversing unwanted consequences following coronary artery bypass graft using saphenous vein.

Implementation of bundled interventions greatly decreases deep sternal wound infection following cardiovascular surgery

OBJECTIVE

Surgical site infection (SSI), particularly deep sternal wound infection (DSWI), is a serious complication after cardiovascular surgery because of its high mortality rate. We evaluated the effectiveness of an SSI bundle to reduce DSWI and identify the risk factors for DSWI.

METHODS

During the period January 2004 to February 2012, 1374 consecutive patients undergoing cardiovascular surgery via sternotomy were included. The cohort was separated into periods from January 2004 through February 2007 (period I, 682 patients) and March 2007 through February 2012 (period II, 692 patients). During period II, all preventive measures for DSWI were completed as an SSI bundle. We compared the DSWI rate between the 2 periods. Univariate and multivariate analyses were performed for the entire period to identify the risk factors for DSWI.

RESULTS

DSWI occurred in 13 patients (1.9%) during period I and in 1 patient (0.14%) during period II. The DSWI rate during period II was significantly decreased by 93%, compared with period I (P=.001). Independent risk factors for DSWI included obesity (odds ratio [OR], 3.4; 95% confidence interval [CI], 1.00-11.75; P=.049), the use of 4 sternal wires (OR, 8.2; 95% CI, 1.39-48.14; P=.020), long operative time (OR, 4.4; 95% CI, 1.20-16.23; P=.026), and postoperative renal failure (OR, 9.0; 95% CI, 2.44-33.30; P=.001).

CONCLUSIONS

Complete implementation of simple multidisciplinary prevention measures as a bundle can greatly decrease the incidence of DSWI.

Bilateral internal mammary artery grafting

The superiority of the left internal mammary artery over the saphenous vein graft led many surgeons to adopt bilateral internal mammary artery (BIMA) as a good surgical option for further improving late outcome of patients undergoing myocardial revascularization. However, routine use of BIMA was limited by some potential drawbacks: the increase of deep sternal wound problems, especially in diabetic patients; the shortness of right internal mammary artery (RIMA), which limited its utilization as an in situ graft; the low patency rate if grafted to the right coronary artery; and the longer operative time. The skeletonization of the internal mammary artery along with a better glucose control in diabetic patients significantly reduced the incidence of deep sternal problems. Another problem to solve was finding the optimal target of the RIMA. The general consensus is that RIMA appears to be more efficient if grafted to the lateral wall. The Y or T configuration of double mammary arteries could be more helpful to reach the lateral target vessels. Finally, recent reports clearly demonstrate the superiority of BIMA over single internal mammary artery in terms of survival or quality of life. The latter finding has also been reported in diabetic patients.

Conduits for coronary bypass: strategies

Strategic planning is integral to any operation but complexity varies immensely and therefore the effort necessary to create the optimal plan. The previous three reports have discussed individual conduits and herein is an attempt to present approaches to common situations which the author favors. Although much has been learned over 45 years about use and subsequent behavior of venous and arterial grafts we continue to learn and, as a result, evolve new strategies or modify those now popular. Thus the reader must recognize that in spite of trying to be balanced and inclusive all surgeons have personal opinions and also prejudices which influence the approach taken and which may not be the optimal one for others or for the patient.

Full myocardial revascularization with bilateral internal mammary artery Y grafts

BACKGROUND

Bilateral internal mammary artery (BIMA) grafting in coronary artery surgery provides better long term outcomes than single internal mammary artery and saphenous vein grafting but the optimum configuration of BIMAs has not been established. This study analyzed perioperative and late outcomes of patients who underwent BIMA grafting with a composite Y configuration.

METHODS

Patients (n=922) who underwent BIMA Y grafting were identified from a cardiac surgical database and then cross matched against hospital and cardiology databases and the state death register to identify episodes of repeat coronary angiography, cardiac surgical re-intervention and death. Analysis of repeat angiography was performed after retrieval of the angiogram reports.

RESULTS

In 95% of patients, full myocardial revascularization was achieved with BIMAs alone, using a composite Y configuration with an average of 4.1 IMA to coronary artery anastomoses per patient. The perioperative mortality was 1.5% and the 5-, 10- and 15-year survival estimates were 95%, 87% and 77% respectively. Analysis of 166 symptom-driven post-discharge coronary angiograms showed grafts to the left anterior descending artery and increasing severity of coronary artery stenosis at preoperative angiography as predictors of anastomotic patency.

CONCLUSIONS

Full myocardial revascularization can be achieved with reasonable safety in most patients with triple vessel disease and good left ventricular function, and provides good late survival.

The art of arterial revascularization-total arterial revascularization in patients with triple vessel coronary artery disease

The use of the left internal thoracic artery to graft the left anterior descending artery has been widely accepted as the gold standard for surgical treatment of coronary disease for over 40 years. However the use of multiple other arterial grafts to support this has not been accepted readily, in spite of evidence of superiority over saphenous vein grafts, probably because of perceptions of technical complexity, time constraints for conduit harvesting and increased peri-operative complications. As a result, even today most patients with multivessel coronary artery disease do not receive the potential benefits of extensive or total arterial revascularization. We discuss here the use of contemporary techniques and grafts configurations to simplify this, and the safety and benefit data underpinning this practice. Current patency data confirm that a left internal thoracic artery graft performs well beyond 20 years, with over 80% freedom from failure, but accumulating data suggest that the right internal thoracic artery behaves in the same way. Radial artery grafts are being studied in several randomized trials, but observational studies already suggest a performance which compares favourably with saphenous vein. Total arterial revascularization is achievable in most patients with a small but acceptable increase in risk of sternal complications when certain defined subgroups are excluded.

A novel composite coronary bypass graft strategy: the saphenous vein bridge--a pilot study

OBJECTIVES

The aim of this pilot study was to describe and assess the safety of a novel composite graft technique for coronary artery bypass grafting (CABG) surgery. A saphenous vein is grafted to the left anterior descending artery (LAD) and other anterolateral coronary arteries, creating a saphenous vein bridge (SVB) and the left internal mammary artery (LIMA) is anastomosed to the SVB, distributing the blood flow distally (LIMA-SVB).

METHODS

All patients who underwent CABG with the LIMA-SVB between 2005 and 2008 at our centre were enrolled in this study. Perioperative data were retrospectively collected from hospital charts, and the clinical follow-up was completed by telephone interview. Graft patency was assessed by computed tomography angiography (CTA) in patients with the longest follow-up time (n = 20).

RESULTS

A total of 256 patients (mean age: 67 ± 12 years; 79% male) received 4.0 ± 1.0 grafts, including 2.2 ± 0.4 distal grafts provided by the LIMA-SVB. Nine (3.5%) deaths and 4 (1.6%) myocardial infarctions (MIs) were noted in the perioperative period. With a median follow-up time of 36 months [inter-quartile range 31-44], 1 (0.5%) MI and 2 (1.0%) strokes were reported. At 51 months post-surgery [47-53], CTA demonstrated a LIMA pedicle (n = 20) and SVB (n = 42) patency rate of 100 and 93%, respectively. Specifically, the LIMA-SVB patency rate was 100% to the LAD and 85% to diagonal arteries. Aortocoronary vein grafts (n = 38) patency rate in the same patients was 87%.

CONCLUSIONS

Revascularization of the anterolateral territory using the LIMA-SVB is a promising approach considering its clinical safety and favourable patency rate results. A prospective randomized clinical trial is underway to compare this technique to conventional CABG.

The history of arterial revascularization: from Kolesov to Tector and beyond

Coronary artery bypass grafting (CABG) is the one of the most effective revascularization strategies for patients with obstructive coronary artery disease. Total arterial revascularization using one or both internal thoracic and radial arteries has been shown to improve early outcomes and reduce long-term cardiovascular morbidity. Although CABG has evolved from an experimental procedure in the early 1900's to become one of the most commonly performed surgical procedures, there is still significant variation in grafting strategies amongst surgeons. We review the history and development of CABG with a particular emphasis on the early pioneers and the evolution of arterial grafting.

Conduits for Coronary Bypass: Arteries Other Than the Internal Thoracic Artery's

This is the third in a series on coronary artery bypass which reviews three alternative arterial conduits. The radial artery has become the most widely used of the three and accumulating experience demonstrates better patency at 10 years versus saphenous vein. Drawbacks are a long incision on the forearm, the propensity for spasm and persistent sensory disturbance in about 10%. The first is answered by endoscopic harvest which may yield a shorter conduit but reduces sensory nerve injury. Spasm is managed pharmacologically and by less harvest trauma. The gastroepiploic artery is used in situ and free and although the abdominal cavity is entered complications are minimal and patency compares favorably with the radial artery. Use of the inferior epigastric artery remains minimal and its similar length often requires composite use but limited patency data are supportive. Other arteries have had rare use and this is unlikely to change because the three presented here have significant advantages and acceptance.

Conduits for coronary bypass: internal thoracic artery

This second report in the series on coronary artery bypass presents the authors experience and personal views on the internal thoracic artery (ITA) which date to 1966. There has been a very gradual evolution in the acceptance of this conduit which was initially compared with the saphenous vein and viewed as an improbable alternative to it. As is common with concepts and techniques which are 'outside the box' there was skepticism and criticism of this new conduit which was more difficult and time consuming to harvest for the surgeon who had to do it all. It was viewed as small, fragile, spastic and its flow capacity was questioned. Only a few surgeons employed it because of these issues and some of them would frequently graft it to the diagonal artery as it was thought not to supply adequate flow for the left anterior descending unless it was small. After a decade, angiographic data revealed superior patency to vein grafts. Even this evidence and survival benefit reported a few years later did not convince many surgeons that their concerns about limitations justified its use. Thus widespread adaption of the ITA as the conduit of choice for the anterior descending required another decade and bilateral use is only now expanding to more than 5% of patients in the US and somewhat faster in other countries.

Off-pump coronary artery bypass grafting using a bilateral internal mammary artery Y graft

Objective

To evaluate the outcome of off-pump coronary artery bypass grafting (OPCABG) using a bilateral internal mammary artery (BIMA) Y configuration graft to achieve total arterial myocardial revascularization.

Methods

From October 2002 to December 2008, 208 patients (196 males and 12 females) underwent OPCABG using a BIMA Y configuration graft. The average age of the patients was 56.5 ± 11.3 years, with an age range of 33–78 years. A total of 167 (80.2%) cases had triple-vessel disease. Left main stem disease was found in 33 (15.9%) cases, and double-vessel disease was found in 8 (3.9%) cases. The semi-skeletonization technique was used to harvest the two internal mammary arteries (IMAs), and then the free right internal mammary artery was connected end-to-side to the left internal mammary artery (LIMA) in situ to complete the Y configuration graft. Off-pump and sequential anastomosis methods were used to perform coronary artery bypass surgery in all patients. Graft patency was assessed intra-operatively with the HT311 transit time flowmeter.

Results

A total of 728 distal anastomoses were performed in 208 patients, with the average being 3.5 ± 1.3 per person. No one died or experienced recurrent angina within 30 days after the operation.

Conclusions

OPCABG using the BIMA Y graft was safe and effective to achieve total arterial revascularization. This method avoids surgical operation on the ascending aorta and other incisions.

Anaortic, total-arterial, off-pump coronary artery bypass surgery: why bother?

Coronary artery bypass grafting (CABG) remains the standard of care for multi-vessel coronary disease. However, the increased rate of peri-operative stroke reported after surgery compared to percutaneous coronary intervention (PCI) remains of concern. Anaortic, total-arterial, off-pump coronary artery bypass (OPCAB) grafting is a technique that offers the main advantages of surgical revascularisation with a rate of stroke that is equivalent to that of PCI. Some recent trials comparing conventional on-pump CABG with OPCAB have questioned the efficacy of the off-pump technique - these are most often performed with manipulation of the ascending aorta. We review the potential benefits of the anaortic, total-arterial OPCAB technique to explain why it is being employed by an increasing number of surgeons.

Total Arterial Off-pump Coronary Revascularization with a Bilateral Internal Mammary Artery Y Graft (208 cases)

Objective:

The aim was to evaluate the early outcome of off-pump coronary artery bypass grafting (OPCABG) with a bilateral internal mammary artery (BIMA) Y configuration graft to achieve total arterial myocardial revascularization.

Materials and Methods:

From October 2002 to December 2008, 208 patients (196 male and 12 female patients) underwent OPCABG by only using a BIMA Y configuration graft. The average age of the patients was 56.5±11.3 years, with the age range being 33–78 years. A total of 167 (80.2%) cases had triple-vessel disease. Left main stem disease was found in 33 (15.9%) cases, and double-vessel disease was found in 8 (3.9%) cases. The semiskeletonization skill was used to harvest the two IMAs, and then the free right internal mammary artery was anastomosed end-to-side to the in situ left internal mammary artery to composite a Y configuration graft. Off-pump and sequential anastomosis methods were used to perform coronary artery bypass surgery for the patients. Graft patency was assessed by using the HT311 transit time flowmeter (USA Transonic Systems Inc.), intraoperatively.

Results:

We performed distal anastomoses of the grafts in 728 patients, the average being 3.5±1.3 per person. No one died and got recurrent angina within 30 days after operation.

Conclusion:

OPCABG by using the BIMA Y graft was safe and effective to achieve total arterial revascularization, and avoid surgical operation on the ascending aorta, and other incisions.

Anaortic coronary bypass surgery

Review of the benefits and techniques for anaortic coronary bypass surgery.

Comparison of fractional flow reserve of composite Y-grafts with saphenous vein or right internal thoracic arteries

BACKGROUND

Composite Y-grafts, using the left internal thoracic artery as the inflow, allow a more efficient use of conduits without the need to touch a diseased ascending aorta. Among other conduits, the saphenous vein graft may be an alternative to the radial artery in elderly patients.

PATIENTS AND METHODS

We evaluated the hemodynamic characteristics of 17 composite Y-grafts made with the left internal thoracic artery anastomosed to the left anterior descending coronary artery in all cases and with either the free right internal thoracic artery (RITA group, n = 10) or a saphenous vein graft (SVG group, n = 7) implanted proximally to the left internal thoracic artery and distally to the circumflex territory 6 months after the operation.

RESULTS

At baseline, the pressure gradient measured with a 0.014-inch pressure wire was minimal between the aorta and the internal thoracic artery stem (2 +/- 1 mm Hg), the internal thoracic artery and left anterior descending (4 +/- 2 mm Hg), the internal thoracic artery and left circumflex (3 +/- 1 mm Hg), and the saphenous vein graft and left circumflex (2 +/- 2 mm Hg). During hyperemia induced by adenosine, the pressure gradient increased significantly to 6 +/- 2 mm Hg in the internal thoracic artery stem, 9 +/- 4 mm Hg in the internal thoracic artery and left anterior descending artery, 9 +/- 3 mm Hg in the internal thoracic artery and left circumflex, and 7 +/- 4 mm Hg in the saphenous vein graft and left circumflex. Fractional flow reserve was 0.94 +/- 0.02 in internal thoracic artery stem, 0.90 +/- 0.04 mm Hg in the internal thoracic artery and left anterior descending, 0.91 +/- 0.03 mm Hg in the internal thoracic artery and left circumflex, and 0.92 +/- 0.06 mm Hg in the saphenous vein graft and left circumflex. No difference between the two types of composite Y-grafts was observed for pressure gradients or fractional flow reserve measured in internal thoracic artery stem or in distal branches.

CONCLUSIONS

Composite Y-grafts with saphenous vein or right internal thoracic arteries allow similar and adequate reperfusion of the left system with minimal resistance to maximal flow and an even distribution of flow in both distal branches.

Y grafting for coronary artery bypass: is it as good as single grafting?

PURPOSE OF REVIEW

The use of multiple arterial grafting has gained popularity in recent years due to its clinical advantages when compared with conventional CABG surgery. The purpose of the present review is to focus in particular on the safety and efficacy of composite Y grafting in coronary surgery.

RECENT FINDINGS

Several studies demonstrated mid-term and long-term benefits of total arterial myocardial revascularization when compared with conventional CABG, that is utilizing the left internal mammary artery and multiple veins. Nevertheless, there have been concerns whether it is safe to have a single inflow rather than multiple aorto-coronary grafts. There is evidence in literature that composite arterial grafting is nowadays a well established technique, and several configurations can be performed according to the specific patients' needs. Moreover, the use of Y grafting completely avoids aortic manipulation, especially when used in association with the off-pump technique.

SUMMARY

Composite Y grafting with the exclusive use of arterial conduits is a well tolerated and effective technique. The choice of the second arterial conduit should be tailored according to the specific patients' characteristics. The association of composite arterial grafting and off-pump technique allows a no-touch technique of the ascending aorta, thereby also minimizing the risk of neurological events.

Does bilateral pedicle internal thoracic artery harvest increase the risk of mediastinitis?

PURPOSE

Bilateral in situ internal thoracic artery (ITA) bypassing may result in excellent myocardial revascularization without increasing the risk of deep sternal wound infection. Although there have been concerns with the use of pedicled bilateral ITA, the risk of infection may not be greater than the use of skeletonized ITA.

MATERIALS AND METHODS

The present study was retrospectively undertaken to determine if pedicled BITA grafts are associated with a higher risk of sternal wound complications. A total of 207 patients who underwent bilateral ITA bypasses with or without existing diabetes mellitus, and 162 patients of those received bilateral pedicled ITA and 98 patients received unilateral ITA bypass grafts.

RESULTS

No sternal wound complications were noted in either the bilateral ITA or unilateral left ITA groups.

CONCLUSION

Bilateral pedicled ITA harvesting was not associated with a greater incidence of infectious sternal complications compared to patients receiving unilateral ITA bypass grafts.

Late results of conventional versus all-arterial revascularization based on internal thoracic and radial artery grafting

BACKGROUND

Use of one or more arterial grafts to revascularize two-vessel and three-vessel coronary artery disease has been shown to improve coronary artery bypass graft surgery (CABG) survival. Yet, the presumed long-term survival benefits of all-arterial CABG have not been quantified.

METHODS

We compared propensity-adjusted 12-year survival in two contemporaneous multivessel primary CABG cohorts with all patients receiving 2 or more grafts: (1) all-arterial cohort (n = 612; 297 three-vessel disease [49%]); and (2) single internal thoracic artery (ITA) plus saphenous vein (SV) cohort (n = 4,131; 3,187 three-vessel disease [77%]).

RESULTS

Early (30-day) deaths were similar for the all-arterial and ITA/SV cohorts (8 [1.30%] versus 69 [1.67%]) whereas late mortality was substantially greater for the ITA/SV cohort (85 [13.9%] versus 1,216 [29.4%]; p < 0.0001). The risk-adjusted 12-year survival was significantly better for all-arterial (with a risk ratio [RR] = 0.60; 95% confidence interval [CI]: 0.48 to 0.75; p < 0.001), but this benefit was true only for three-vessel disease (RR = 0.58; 95% CI: 0.43 to 0.78; p < 0.001) and not for two-vessel disease (RR = 0.97; 95% CI: 0.66 to 1.43; p = 0.89). The all-arterial survival benefit was also true for varying risk subcohorts: no diabetes mellitus (RR = 0.50; 95% CI: 0.37 to 0.69), diabetes mellitus (RR = 0.77; 95% CI: 0.56 to 1.07), ejection fraction 40% or greater (RR = 0.60; 95% CI: 0.45 to 0.78), and ejection fraction less than 40% (RR = 0.62; 95% CI: 0.40 to 0.98). Lastly, the multivariate analysis indicated a strong long-term effect of completeness of revascularization, particularly for all-arterial patients, so that compared with patients with two grafts, survival was significantly better when three grafts (RR = 0.54; 95% CI: 0.33 to 0.87) or four grafts (RR = 0.40; 95% CI: 0.21 to 0.76) were completed.

CONCLUSIONS

All-arterial revascularization is associated with significantly better 12-year survival compared with the standard single ITA with saphenous vein CABG operation, in particular for triple-vessel disease patients. The completeness of revascularization of the underlying coronary disease is critical for maximizing the long-term benefits of arterial-only grafting.

Patch aortoplasty for proximal anastomosis of coronary artery bypass grafts in patients with complex aortic pathology

Proximal anastomosis of conduits to the ascending aorta in patients undergoing coronary artery bypass grafting may be hazardous or impossible in the presence of complex aortic pathology. We describe a technique of the excision of a segment of the diseased aortic wall, reconstruction with a bovine pericardial patch, and attachment of the grafts to the patch. The technique was used successfully in 2 patients (ie, 1 patient with Takayasu's disease and the other with a heavily calcified aorta).

Configurations and classifications of composite arterial grafts in coronary bypass surgery

The aim of this review is to present the configurations and classifications of composite arterial grafts in coronary bypass surgery. Articles were collected by tracking references cited in the literature with regard to the configurations of composite arterial grafts in coronary bypass surgery. Figures of the configurations were drawn in accordance to the schematic drawings, angiograms, photographs, table contents or written captions of the literature. According to their structural nature, composite arterial grafts can be classified as: (i) alphabetical (Y, T, I, U, K, X and H) and (ii) complex grafts (TY, loop, pi and sling grafts). According to the conduits that form the composite graft, they can be classified as: (i) definite (all standard alphabetical grafts, classic pi and sling grafts); (ii) varying [internal mammary artery (IMA) loop, modified pi graft]; and (iii) indefinite conduit graft (TY graft). According to their application in coronary artery bypass grafting (CABG), they can be divided into complete arterial revascularization for: (i) triple vessel disease (T, Y, K, X, TY, pi and sling grafts); (ii) two vessel disease (U, right Y, and two-thirds right IMA T grafts); and (iii) single vessel disease, mainly the left anterior descending artery with or without the diagonal branch (H, I, IMA loop and left IMA T grafts). According to the CABG method, they can be classified as: (i) for conventional CABG (sling graft); (ii) for minimally invasive direct coronary artery bypass (H graft); and (iii) for both conventional CABG and off-pump coronary artery bypass (T, Y, U, K, I, TY, IMA loop, and pi grafts). Standard Y and T grafts have been accepted as the common figurations of composite arterial grafts to maximum graft length for the bypass of triple vessel disease. Composite arterial grafts overcome the limited availability of arterial conduits for performing total arterial myocardial revascularization, allow a gain in conduit length, and minimize the ascending aorta manipulation.