Creative arterial bypass grafting can be performed on the beating heart

Thrombelastographic changes in OPCAB surgical patients

The purpose of this study was to determine whether thrombelastography could detect hypercoagulability in the off-pump coronary artery bypass (OPCAB) patient. Seventeen OPCAB and six cardiopulmonary bypass (CPB) patients were studied pre- and postprocedure, as well as on each of the first three postoperative days (POD). In the OPCAB patients, there was a small reduction in the postprocedure coagulation index (CI). This was followed by an increase in the CI on each of the next three POD, reaching a level exceeding the mean preprocedure CI by 2.32 units, indicative of a state of relative hyper- coagulability. The mean CI for the CPB patients decreased significantly in the postprocedure sample. Over the next 72 h, the CI increased to a level that nearly equaled the preprocedure ‘baseline’. We concluded that our study identified a state of relative hypercoagulability in the OPCAB patient 72 h after surgery. The mechanism of this hypercoagulation, as well as the clinical significance of this finding, is yet to be determined.

Composite arterial grafting

The success of coronary artery bypass grafting, the gold standard for the treatment of multivessel coronary artery disease, is limited by poor long-term vein-graft patency. By contrast, the left internal mammary artery has been demonstrated to have a superior graft patency rate and has provided excellent clinical results. This suggests that the use of arterial conduits for coronary artery bypass grafting may be beneficial for long-term results. Recently, there has been an upsurge in the use of arterial grafts for myocardial revascularization based on the clinical advantage of the use of the left internal mammary artery as a bypass conduit. Many retrospective studies have supported the safety and the effectiveness of arterial grafting, and it has become apparent that the free arterial graft can be used as a branched or a lengthened conduit to the in situ arterial graft by adopting one or more of the several composite grafting techniques. Arterial composite grafts with or without sequential grafting techniques appear an attractive strategy as increased number of distal coronary anastomoses can be performed, with a limited number of grafts, avoiding proximal aortic anastomoses. However, concerns regarding the total dependence of the coronary bypass flow on the flow of one in situ arterial graft and technical error, resulting in compromised flow in one or both limbs of the composite graft have prevented composite arterial grafting from being universally adopted. It is expected that in the near future a prospective, multi-institutional, randomized controlled trial, to compare the short- and long-term outcomes of exclusive arterial grafting using composite and conventional aortocoronary revascularization strategies, will be undertaken to validate the safety and efficacy of composite arterial grafting.

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.

Modifications of composite grafts for coronary bypass surgery

We herein describe four modifications of graft construction in coronary bypass surgery, including composite left mammary arterial T graft, arterial-venous I, and U grafts, and coronary-coronary vein graft and discuss their indications.

Deleterious effects of cardiopulmonary bypass in coronary artery surgery and scientific interpretation of off-pump's logic

Cardiopulmonary bypass (CPB) has been suggested to be a cause of complex systemic inflammatory response that significantly contributes to several adverse postoperative complications. In the last few years, off-pump coronary artery bypass grafting (OPCAB) has gained widespread attention as an alternative technique to conventional on-pump coronary artery bypass grafting (ONCAB). However, a degree of uncertainty regarding the relative merits of ONCAB and OPCAB continues to be a significant issue. Surgeons supporting off-pump surgery, state that the avoidance of the CPB leads to significantly reduced myocardial ischemia-reperfusion injury, postoperative systemic inflammatory response and other biological derangements, a feature that may improve the clinical outcomes. However, perfection in perioperative care, surgical technique and methods of attenuating the untoward effects of CPB has resulted in better clinical outcome of ONCAB as well. Possible reasons of these controversial opinions are that high-quality studies have not comprehensively examined relevant patient outcomes and have enrolled a limited range of patients. Some studies may have been too small to detect clinically important differences in patient outcomes between these two modalities. We present a review of the available scientific interpretation of the literature on OPCAB with regard to safety, hemodynamic changes, inflammation, myocardial preservation and oxidative stress. We also sought to determine from different reported retrospective and randomized control studies, the initial and the long-term benefits of this approach, despite the substantial learning curve associated with OPCAB.

Total Arterial Myocardial Revascularization Using Composite and Sequential Grafting With the Off-Pump Technique

BACKGROUND

Multiple arterial myocardial revascularizations are increasingly undertaken using off-pump techniques; however, various arterial grafting techniques are utilized. This study aimed to review the outcome of combining arterial composite and sequential grafting with off-pump techniques.

METHODS

We retrospectively reviewed the records of 107 consecutive patients who underwent coronary bypass surgery with off-pump and arterial composite grafting techniques between April 2001 and March 2004. The left internal thoracic artery (LITA) was harvested in all patients, and the right internal thoracic artery (RITA), the radial artery (RA), and the gastroepiploic artery (GEA) were harvested in 69 patients, in 83 patients, and in 53 patients, respectively. Early postoperative angiograms were evaluated in 97 patients.

RESULTS

There were 488 distal anastomoses, an average of 4.5 per patient. Forty-four in situ LITAs were used as LITA Y-composite grafts with a free RITA (n = 19), RA (n = 24), or free GEA (n = 1). Forty-three in situ RITAs were used as RITA-RA grafts (n = 42) or a RITA-GEA graft (n = 1). Twenty-one in situ GEAs were used as composite grafts with the RA (n = 17) or a free RITA (n = 4). There were no hospital deaths. The patency of the LITA was 100%, and that of the RA was 97.3%, while patencies of both in situ and free RITA and GEA were 100%. During the follow-up period (mean: 22.1 months), there were 3 late deaths, but none were cardiac related.

CONCLUSIONS

Total arterial revascularization with composite and sequential grafting is a safe and effective technique in patients undergoing off-pump coronary artery bypass surgery.

Role of Radial Artery Graft in Coronary Artery Bypass Grafting

The use of the radial artery (RA) as a coronary artery bypass graft has assumed a revival and thus a multitude of issues have arisen surrounding the routine and widespread use of this conduit in myocardial revascularization. There has been no uniformity regarding harvest techniques, assessment of the adequacy of hand collateral circulation, antispasm protocols, selection of target vessels, and the site of proximal anastomosis. It is widely believed and practiced that the RA should be harvested as a pedicle graft and preferably be used to bypass critically stenosed (>70% stenosis) coronary arteries. It is used either as a free graft with proximal anastomosis to the ascending aorta or as a composite arterial graft along with the left or right internal thoracic artery. The patency of RA grafts depends on the severity of the target coronary artery stenosis and target artery location rather than its use as an aortocoronary conduit or composite graft. In this article, we reviewed the current knowledge regarding the use of RA grafts as a coronary bypass conduit in an attempt to suggest a few acceptable strategies concerning the above issues in a given clinical scenario.

Synergy of old and new technology results in successful revascularization of the anterior myocardium with relief of angina in the absence of suitable targets

BACKGROUND

Diffuse and distal left anterior descending (LAD) coronary disease that is refractory to conventional surgical and/or percutaneous revascularization represents a clinical and economic dilemma. Transmyocardial laser revascularization (TMLR) has improved angina without clear measurable improvement of myocardial perfusion. This study was undertaken to determine if combining a Vineberg implant with TMLR of the LAD distribution enhances myocardial perfusion and relieves symptoms.

METHODS

Twenty-one patients with an obliterated LAD and a viable anterior wall underwent off-pump coronary artery bypass grafting (OPCAB) (2.6 grafts/patient). Eight were studied with preoperative, postoperative-early (4-9 days), and postoperative-late (3-5 months) stress and rest nuclear imaging. In all but 3 cases, the Vineberg implant was modified such that the distal end of the conduit, as it emerged from the muscular tunnel, was anastomosed to any patent LAD segment. The anterior wall, to the left of the LAD, was also instrumented with a Holmium yttriumaluminum- garnet laser (8-16 sites).

RESULTS

There has been 100% follow-up with durations ranging from 6 to 36 months. There were no deaths. All patients had complete relief of their angina. Serial perfusion scans demonstrated a 2-phase improvement in perfusion. Three of the patients underwent angiography of the implant at 6 to 9 months; angiography in each case demonstrated a patent robust conduit. The 1 patient studied at 24 months demonstrated several sites of a myocardial "blush" consistent with neovascularization.

CONCLUSIONS

Although some of the benefits of TMLR/Vineberg may be a consequence of collateral blood flow from other revascularized regions, we believe there to be a synergistic effect on perfusion and angina relief by these combined procedures which may be related to angiogenesis.

Total arterial myocardial revascularization: analysis of initial experience

BACKGROUND

Total arterial myocardial revascularization is an attempt to overcome the problems of late vein graft atherosclerosis, occlusion and need for coronary re-operations. Despite increasing evidence of efficacy, the use of arterial conduits has not been accepted as a primary practice in most of the centers in Pakistan for various reasons. We analyze our initial experience to assess the feasibility of total arterial revascularization as a primary strategy in patients requiring first time coronary artery bypass grafting.

METHODS

Two hundred patients undergoing first time CABG at our institution, from January 2000 to April 2001, were studied. Group 1 consisted of 100 patients undergoing total arterial revascularization (using bilateral internal thoracic and radial arteries) and Group 2 consisted of 100 patients undergoing conventional CABG (using one internal thoracic artery and supplemental veins). Thirty-day mortality and early morbidity with particular reference to resternotomy for bleeding, cerebrovascular accidents, renal failure, and sternal dehiscence were the main outcome measures.

RESULTS

Patients in Group 1 were younger (56.2 +/- 10.4 vs. 60.3 +/- 9.8 years; P < 0.001), had lower Parsonnet scores (4.8 +/- 0.4 vs. 9.6 +/- 1.8; P < 0.001), and had better left ventricular function. Both groups received a similar number of grafts. The percentage of patients undergoing total arterial revascularization rose from 20% in the first three months to over 65% in the three later three-month periods. Overall 30-day mortality was 1.5%, one patient (1%) in Group 1 and two patients (2%) in Group 2. There was a similar incidence of postoperative complications and length of median postoperative stay in both groups.

CONCLUSION

Total arterial revascularization can be adopted as a primary strategy in most patients undergoing CABG with no increase in mortality or morbidity.

Total Arterial Off-Pump versus On-Pump Coronary Revascularization:. Comparison of Early Outcome

BACKGROUND AND AIM

To assess differences in the early outcome after complete arterial myocardial revascularization with (ONCAB) or without cardiopulmonary bypass (OPCAB).

METHODS

Out of 870 consecutive CABG procedures 58 OPCAB and 91 ONCAB patients receiving exclusive arterial grafts were analyzed. OPCAB patients had more single-vessel (p < 0.0001), less triple-vessel (p < 0.0001) or left main disease (p = 0.0021), higher angina class (p = 0.003), unstable angina (p < 0.0001) or previous PTCAs (p < 0.0001).

RESULTS

ONCAB was associated with longer operations (182.5 +/- 38 vs. 147 +/- 56 min; p = 0.0001) and more anastomoses/patient (3.2 +/- 1 vs. 2 +/- 0.9; p < 0.0001), but incomplete revascularization was similar in both groups (11% vs. 17%; p = ns). ITA use was identical, whereas single left internal thoracic artery (LITA) use (25.9% vs.1%; p < 0.0001) and LITA jump anastomoses (10.3% vs. 7.7%; p < 0.0001) were more frequent in OPCAB. Radial artery (RA) use (89% vs. 46.6%; p < 0.0001) and RA jump anastomoses (57.1% vs. 12.1%; p < 0.0001) were more frequent in ONCAB. Mortality, arrhythmias, cerebro-vascular accidents (CVA), and renal failure were similar, but ventilatory support shorter (8.8 +/- 11.8 vs. 15.6 +/- 9.4 h; p < 0.0001) and cardiac enzyme release smaller (p < 0.0001) after OPCAB with a trend toward less myocardial infarction (1.7% vs. 7.7%; p = 0.12) and low output (1.7% vs. 8.8%; p = 0.089), and more respiratory complications (10.3% vs. 2.2%; p = 0.056).

CONCLUSIONS

Arterial OPCAB patients have less extensive CAD, but more severe symptoms. Early outcome is similar concerning mortality, arrhythmias, CVA, renal failure, or ICU and hospital stay, but with shorter ventilatory support and lower cardiac enzymes with a trend toward lower myocardial infarction and low output, but higher respiratory complication rates after OPCAB.

Total Arterial Revascularization for Multiple Vessel Coronary Artery Disease: With or without Cardiopulmonary Bypass

BACKGROUND

To assess the usefulness of off-pump technique for more technically demanding coronary artery bypass procedures using exclusively arterial conduits.

METHODS

Analysis of perioperative data of 324 consecutive patients in whom total arterial revascularization for multiple- vessel coronary artery disease was performed--181 cases on-pump and 143 cases off-pump.

RESULTS

On average in the on-pump group 2.7 +/- 0.8 (range, 2-5) grafts per patient were constructed versus 2.4 +/- 0.7 (range, 2-4) grafts per patient in the off-pump group (P < .001). Of the total number of 490 anastomoses performed on-pump, 83 (17%) were side-to-side and of 349 anastomoses performed off-pump, 51(15%) were side-to-side, a nonsignificant difference (P = .4). The aorta was used as a site for proximal anastomosis of 1 or more arterial conduits in 105 patients (58%) who underwent on-pump surgery and in 57 patients (40%) who underwent off-pump surgery (P = .002). In the off-pump group, the right internal thoracic artery (RITA) was rarely (12%) routed through the transverse sinus to circumflex branches compared with the on-pump group (34%) (P = .017). RITA in off-pump patients was more often used to revascularize the anterior wall (47% versus 29%; P = .08). We observed no difference in mortality (1.7% versus 0%; P = .3), incidence of perioperative myocardial infarction (8.8% versus 7.7%; P = .8), stroke (1.7% versus 1.4%; P = .8), or atrial fibrillation (24% versus 19%; P = .3). We observed less inotropic support and less blood-product use in off-pump patients.

CONCLUSION

Total arterial revascularization for multiple-vessel coronary artery disease may be safely performed off-pump. We observed tendency to somewhat smoother postoperative course in the off-pump group.

Total arterial revascularization with composite skeletonized gastroepiploic artery graft in off-pump coronary artery bypass grafting

BACKGROUND

Total arterial revascularization in coronary artery bypass grafting has recently become of great interest to many surgeons. At the same time, off-pump coronary bypass grafting has also become a popular procedure because of its low morbidity and mortality. Here we report our recent series of off-pump coronary bypass grafting performed with a grafting technique we developed by using the skeletonized gastroepiploic artery and the radial artery composite graft to achieve total arterial revascularization.

METHODS

From September 2000 to April 2003, 98 patients underwent total arterial revascularization with the skeletonized gastroepiploic artery and radial artery composite graft on the beating heart. We used the gastroepiploic artery graft of choice in patients with a right coronary artery lesion. When multiple grafting was required in inferior, posterolateral, or lateral ventricular walls and the gastroepiploic artery graft was too short to cover these areas, we used the composite grafting technique.

RESULTS

There were no in-hospital deaths and there was no severe morbidity among the study patients. Postoperative angiography showed graft occlusion at the anastomosis site between the gastroepiploic and radial arteries. The patency rate of the gastroepiploic arterial composite graft was 98.3% (118/120 distal anastomoses).

CONCLUSIONS

A composite graft with the skeletonized gastroepiploic artery and the radial artery ensured sufficient caliber size and length for myocardial revascularization on inferior, posterolateral, and lateral ventricular walls. This composite graft can be used safely and effectively even in off-pump coronary bypass surgery with excellent early clinical and angiographic outcome in selected patients, although longer follow-up periods are necessary to draw definitive conclusions.

Early results of complete off-pump coronary revascularization using left internal thoracic artery with composite radial artery

OBJECTIVE

Off-pump coronary artery bypass (OPCAB) using the left internal thoracic artery (LITA) with a composite radial artery (RA) was employed for arterial revascularization in order to minimize neurological complication.

METHODS

Sixty-one patients underwent OPCAB using the LITA with a composite RA. Angiography was performed in all patients at two weeks postoperatively.

RESULTS

The mean number of distal anastomoses was 3.2 +/- 0.4. A Y-composite graft was used in 55 patients, and K-composite graft was used in the other 6 patients. There was no hospital death, no neurological complication nor deep sternal infection. Furthermore, there was no episode of perioperative myocardial infarction nor hypoperfusion syndrome. Patients have been angina-free during a mean follow-up period of 1 year. The graft patency of the LITA to the left anterior descending artery (LAD) was 100% (61/61 anastomoses). The RA became occluded in 4 patients, and the patency rate was 95.6% (130/136 anastomoses). String or coronary-coronary bypass resulting from flow competition was observed in the LITA of 6 patients and in the RA of 13 patients. The string of the LITA occurred in the segment distal from the anastomosis with the composite RA. The string or coronary-coronary bypass was observed more often in cases in which the recipient coronary artery had less than 75% stenosis.

CONCLUSION

OPCAB using only the LITA with a composite RA can be successfully and safely performed in patients with multivessel disease. Late postoperative follow-up of the flow competition is necessary to delineate the significance of flow competition.

Off-pump coronary revascularization: current state of the art

Patients presenting for surgical coronary artery bypass grafting (CABG) are older and have more comorbidity than patients in prior decades. Cardiopulmonary bypass (CPB) may add to the elevated morbidity and mortality seen in these higher-risk patients. After the re-introduction of single-vessel bypass without CPB, surgeons have developed techniques for multivessel off-pump coronary artery bypass (OPCAB) through sternotomy. Understanding the causes of the hemodynamic disturbances seen during cardiac displacement has led to surgical techniques that minimize mechanical compression and the effects of temporary regional ischemia. With careful attention to detail, OPCAB has been shown to be feasible in nearly all patients needing coronary artery bypass. The procedure has been demonstrated to be safe and effective. Early outcomes and graft patency rates appear to be at least as good as those seen with traditional CPB-supported CABG. Certain high-risk groups may be better treated with OPCAB, but further studies are necessary to elucidate which patients should be offered OPCAB and which should receive standard CABG.