Total arterial myocardial revascularization without cardiopulmonary bypass

The risks associated with cardiopulmonary bypass have led to an interest in coronary surgery without the use of such a bypass. Six patients of mean (s.d.) age 62.0(8.0) (range 52–71) years were selected for elective coronary surgery without cardiopulmonary bypass. In five cases a midline sternotomy and in one case a small anterolateral thoracotomy were performed; in the latter case the harvesting of the proximal end of the left internal mammary artery was video-assisted by thoracoscopy. The left internal mammary artery was used in all cases; the right internal mammary artery was used in one case, the radial artery in four, the inferior epigastric artery in two and the right gastroepiploic artery in one. No patient died or had a stroke. There were no postoperative episodes of low cardiac output syndrome or perioperative myocardial infarction. All patients were extubated within a few hours after surgery. The mean(s.d.) intensive care unit and hospital stays were 1.3(0.5) and 5.0(0.9) days, respectively. Total arterial myocardial revascularization without cardiopulmonary bypass using composite grafts, is a new and promising technique that is feasible with low risks and good early results in selected cases. Copyright © 1996 The International Society for Cardiovascular Surgery.     

全动脉化冠状动脉搭桥的临床应用

目的 介绍全动脉移植物行冠状动脉搭桥的早期效果和临床经验。方法 采用全动脉移植物87例冠心病患者实施冠状动脉搭桥。其中男性患者82例,女性5例;单支冠状动脉病变14例,2支病变19例,3支病变54例。62例患者术前有心肌梗死,7例合并室壁瘤,1例合并主动脉瓣关闭不全。71例患者在体外循环下行冠状动脉搭桥术,16例在非体外循环下行冠状动脉搭桥术。同时行室壁瘤切除术7例,行主动脉瓣替换1例,行冠状动脉内膜剥脱2例。应用左乳内动脉84例次,右乳内动脉46例次,胃 网膜右动脉37例次,左桡动脉51例次。单个远端吻合14例,2个19例,3个50例,4个4例。结果 围手术期死亡2例（病死率2．3％）,1例为围手术期心肌梗死低心排,1例为顽固性心律失常。3例术后发生胸骨裂开切口感染,再次清创处理后痊愈。本组患者随访1．0－30．0个月（平均13．2个月）,1例患者因突发脑血管意外在术后40d死亡,其余患者术后均恢复良好,无心绞痛症状再发。B超检查乳内动脉移植血管均通畅。结论 全动脉化冠状动脉搭桥具有良好的临床应用效果,尤其适合于年轻的冠心病患者。     

Comparative anatomic studies of various arterial conduits for myocardial revascularization

Comparison was made between the morphologic condition of the left anterior descending artery and four arterial conduits: the internal mammary, right gastroepiploic, inferior epigastric, and radial arteries, harvested from 17 patients (aged 15 to 85 years, mean 64 years) who had died of nonvascular diseases. Proximal, mid, and distal segments were examined microscopically. The internal mammary artery was elastic, but the others were muscular. In all four conduits, atherosclerosis was absent to mild, the internal elastic lamina showed only minimal defects, and the vasa vasorum were confined to the adventitia. In all cases the left anterior descending artery showed mild to severe atherosclerosis and substantial defects in the internal elastic lamina with penetration of the vasa vasorum into the media and intima. Comparison of the mean distance (+/- standard deviation) from the lumen to the outermost portion of the media for the left anterior descending artery (320 +/- 63 microns) with the four conduits gave comparable values for the internal mammary artery (350 +/- 92 microns); p = not significant) and the right gastroepiploic artery (291 +/- 109 microns; p = not significant), versus 529 +/- 52 microns; p less than 0.002) for the radial artery and 249 microns (+/- 87 microns) (p less than 0.04) for the inferior epigastric artery (Kruskal-Wallis and Mann-Whitney U tests). The relatively scanty presence of smooth muscle cells in the thin-walled media of the internal mammary artery combined with a well-formed internal elastic lamina, even at advanced age, may be an important cause for its low susceptibility to atherosclerosis and a major determinant in its superior long-term patency as a coronary artery bypass graft. This finding emphasizes the justification of continued use of the ideally matching internal mammary artery, either as in situ or free graft, in coronary artery bypass grafting. In contrast to the thick-walled radial artery, which may be relatively prone to ischemia, an acceptable long-term patency of the inferior epigastric artery and right gastroepiploic artery, if harvested as pedicled grafts, is anticipated.     

Off-pump myocardial revascularization using arterial conduits without cardiopulmonary bypass.

OBJECTIVE: The feasibility of myocardial revascularization via a median sternotomy with arterial conduits, without and with cardiopulmonary bypass (CPB), was evaluated. MATERIAL AND RESULTS: From May 21, 1997, to November 30, 1999, 721 patients had myocardial revascularization without CPB via median sternotomy using at least two arterial conduits. The procedure was performed without CPB in 322 patients (Group A); the remaining 399 patients (Group B) underwent the same operation with the aid of CPB. Group A patients were older, with a higher ejection fraction and less redo than Group B. There was no early death in Group A versus nine (2.3%) patients in Group B (p < 0.02). Incidence of cerebrovascular accident (CVA) and acute myocardial infarction (AMI) were similar in both groups. Early major events incidences were 1.2% versus 8.0% (p < 0.001) in Groups A and B, respectively. Postoperative angiographic controls showed a cumulative patency rate of 98.4% and a perfect patency rate of 96.7%. After 30 months, Groups A and B showed an actuarial survival of 98.1 +/- 0.7 and 96.5 +/- 2.8 (p = ns) and an event-free survival of 96.6 +/- 1.0 and 96.5 +/- 2.8 (p = ns), respectively. CONCLUSION: Myocardial revascularization without CPB using arterial conduits can be accomplished with the same quality of results obtained with the use of CPB.     

Thoracodorsal artery as a free arterial graft for myocardial revascularization

When complete arterial revascularization of coronary circulation cannot be accomplished using the internal thoracic artery and other conventionally used arterial conduits, the thoracodorsal artery may be an excellent alternative. We report the use of the thoracodorsal artery as a free arterial graft in 3 patients, describe the harvesting technique, and review the anatomy.     

Role of right gastroepiploic artery in myocardial revascularization with arterial grafts

Between July 1990 and December 1992, 112 patients underwent myocardial revascularization with arterial grafts in the Department of Cardiac Surgery, University of Milan. Monovascular patients were excluded from the study. The right gastroepiploic artery was used in 44 patients (39.3%); mean age was 54.3 years and reoperation rate 18.2%. Of the 44 patients, previous myocardial infarction had occurred in 25 (57%). Emergency operation was performed in one case (2%). Mean left ventricular shortening fraction was 36% and mean ejection fraction 58.6%. Coronary artery disease was bivascular in 10 patients (23%) and trivascular in 34 (77%). The arterial revascularization in patients with gastroepiploic artery was performed using a left internal thoracic artery graft in all 44 patients; the right internal thoracic artery was used in 18 (41%) and the inferior epigastric artery in two (4%). The sites of gastroepiploic artery grafting were 55% posterior descending, 16% right coronary artery, 11% posterolateral branch, 14% circumflex and in 4% posterior descending and posterolateral as sequential graft. No patient died; postoperative myocardial infarction rate was 4%. No complications related to gastroepiploic artery utilization were noted. Forty-three (98%) of the gastroepiploic artery group underwent graft reinvestigation: the arteries were correctly visualized in 41 patients (95%) and were patent in 39 cases and stenotic in two. A mid-term postoperative stress test (mean 17.4 months) was performed in 91% of patients. Normal limits were found in 37 patients (92.5%) and an abnormal stress test result in three (7.5%). The contemporary follow-up showed no deaths or myocardial infarctions. Three patients (7%) had recurrent angina. The rote of gastroepiploic artery in arterial revascularization has become fundamental, especially, it is believed, for the posterior or posterolateral left ventricular wall. The present data show the patients to be clinically and functionally well 1 year after operation.     

Off-pump total arterial myocardial revascularization according to the right Y-graft configuration

OBJECTIVES: The aims of this study were as follows: 1) to evaluate the early outcome of the off-pump total arterial myocardial revascularization according to the right y-graft (lambda-graft) configuration and 2) to compare baseline flow and maximum flow between patients undergoing on-pump and off-pump right y-graft (RYG) construction. METHODS: Between December 1998 and January 2001, 47 patients (Group I) and 20 patients (Group II) with three vessel disease underwent on-pump and off-pump coronary artery bypass graft (CABG) respectively according to the RYG configuration. The mean age was 55.5 +/- 4.7 years and 55 +/- 6.4 years in Groups I and II, respectively. The RYG was constructed employing both internal mammary arteries (IMAs) only, in 21 and 8 patients in Groups I and II, respectively, presenting proximal-middle third stenosis of the left anterior descending artery (LAD) and right coronary artery (RCA). The modified RYG configuration employing both IMAs and radial artery (RA) was performed in 26 and 12 patients in Groups I and II, respectively, presenting middle-distal third stenosis of the LAD and distal stenosis of the RCA or posterior descending artery stenosis. Postoperatively all patients underwent transthoracic echo color-Doppler (TTECD) contrast enhanced (by Levovist) before and after adenosine provocative testat one week and three months after operation. RESULTS: There were no hospital deaths. The mean mechanical ventilation was significantly different in Group I versus Group II patients, 18 +/- 4.4 hours versus 13 +/- 5.7 hours, respectively (p = 0.041). The mean intensive care unit stay was 1.5 +/- 0.6 days in Group I and 1 +/- 0.4 days in Group II (p = 0.033). There were no differences between Groups I and II regarding the IMA diameter, mean velocity, and mean flow. At follow-up time, 6 +/- 2.4 months after the surgical procedure, all patients were alive and free of angina. The coronary flow reserve (CFR) at LIMA main stem was significantly higher at three months when compared to the values at one week after the surgical procedure within the same group, (LIMA)CFR (three months) = 2.37 +/- 0.6 versus (LIMA)CFR (one week) = 2.07 +/- 0.4 (p = 0.005) in Group I and (LIMA)CFR (three months) = 2.4 +/- 0.4 versus (LIMA)CFR (one week) = 2.06 +/- 0.3 (p = 0.004) in Group II. Similarly, the CFR at RIMA main stem were significantly higher at three months when compared to the values at one week after the surgical procedure: (RIMA)CFR (three months) = 2.47 +/- 0.7 versus (RIMA)CFR (one week) = 2.1 +/- 0.5 (p = 0.004) in Group I and (RIMA)CFR (three months) = 2.48 +/- 0.5 versus (RIMA)CFR (one week) = 2.08 +/- 0.4 (p = 0.008) in Group II. CONCLUSION: The flow dynamic data, almost identical between patients undergoing off-pump and on-pump total arterial myocardial revascularization (TAMR) according to the RYG configuration, demonstrate that this technique can be applied with excellent results without the employment of cardiopulmonary bypass in selected coronary artery disease patients.     

Occurrence of myocardial ischemia immediately after coronary revascularization using radial arterial conduits

OBJECTIVE: To assess the incidence of myocardial ischemia in patients receiving radial arterial and left internal thoracic arterial conduits (RA+LITA) during the postrevascularization period. DESIGN: Nonrandomized observational sequential cohort. SETTING: University hospital. PARTICIPANTS: Thirty adult patients, scheduled for elective coronary artery bypass graft surgery with RA+LITA, compared with 30 patients who received saphenous vein graft and left internal thoracic arterial conduits. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Myocardial ischemic episodes were defined as reversible ST-segment depressions or elevations >or=1 mm and >or=2 mm at J +60 msec and lasting >or=1 minute using 2-channel Holter monitoring. During the post-cardiopulmonary bypass period, a significantly higher number of patients with >or=2 mm ischemic episodes (21.7%; p = 0.015) and higher number of >or=2 mm ischemic episodes per hour (0.19 +/- 0.4 episodes/hr; p = 0.03) were observed in the radial artery group versus the comparison group (0% of patients and 0 episodes/hr). During the postoperative period (24 hours), a significantly longer duration of >or=2 mm ischemic episodes was observed in the radial artery group (24 +/- 33 minutes v 8.4 +/- 21 minutes; p = 0.046). Radial artery graft, preoperative calcium antagonists, and pulmonary arterial mean pressure were independent predictors of the duration and area under the ST-segment curve of >or=2 mm ischemic episodes during the postoperative period. CONCLUSION: There is an association between the use of the radial artery graft and the incidence and severity of >or=2 mm postrevascularization ischemic episodes.     

Deep circumflex iliac artery as a free arterial graft for myocardial revascularization

When complete revascularization cannot be obtained with the internal thoracic artery and the other arterial grafts, the deep circumflex iliac artery (DCIA) may be an excellent alternative conduit. The deep circumflex iliac artery was used as a free graft for direct myocardial revascularization in 4 patients from January to July 1999. We describe our experience with this arterial conduit, review the anatomy of the artery, and present our harvesting technique.     

Hybrid myocardial revascularization

Background

In patients with advanced coronary artery disease (CAD), coronary artery bypass grafting (CABG) is associated with improved long-term outcomes while percutaneous coronary intervention (PCI) is associated with lower periprocedural complications. A new approach has emerged in the last decade that attempts to reap the benefits of bypass surgery and stenting while minimizing the shortcomings of each approach, hybrid myocardial revascularization (HMR).Three strategies for timing of the hybrid revascularization exists, each with their own inherent advantages and shortcomings: (1) CABG followed by PCI, (2) PCI followed by CABG, or (3) simultaneous CABG + PCI in a hybrid suite.

Studies

The results of the first randomized control trial comparing HMR (CABG first) and standard CABG, POL-MIDES (Prospective Randomized PilOt Study EvaLuating the Safety and Efficacy of Hybrid Revascularization in MultIvessel Coronary Artery DisEaSe), show HMR was feasible for 93.9% of patients whereas conversion to standard CABG was required for 6.1%. At 1 year, both groups had similar all-cause mortality (CABG 2.9% vs. HMR 2%) and major adverse clinical event (MACE)-free survival rates (CABG 92.2% vs. HMR 89.8%). Results of observational and comparative studies show that minimally invasive HMR procedures in patients with multivessel CAD carry minimal perioperative mortality risk and low morbidity and do not increase the risk of postoperative bleeding. The advantage they offer in comparison to classical surgical revascularization is indeed faster rehabilitation and patient’s return to normal life.

Conclusion

Hybrid myocardial revascularization has been developed as a promising technique for the treatment of high-risk patients with CAD. Hybrid revascularization using minimally invasive surgical techniques combined with PCI offers to a part of patients an advantage of optimal revascularization of the most important artery of the heart, together with adequate myocardial revascularization in a relatively delicate way. Indeed, to patients with high operative risk of standard surgery, it offers an alternative which should be considered carefully.

     

Laser myocardial revascularization

A significant number of patients with ischemic heart disease are not candidates for coronary artery bypass or percutaneous transluminal angioplasty and do not respond to medical management. This group includes those who have diffuse coronary artery disease, those with poor ventricular function, and those who have had poor results from previous surgery. Developing a method to directly revascularize the myocardium by creating channels through the ventricular wall has challenged many investigators. Early methods, including needle acupuncture, were successful in the acute phase, but long-term patency could not be achieved. Closure of the channels was due to fibrosis and scarring. Experiments in our laboratory demonstrated that myocardial channels, made with the CO2 laser, remained patent up to five years. Histopathologic examination of the channels showed minimal damage to the surrounding cells in the acute phase. Studies at intervals of two months to two years showed patent endothelialized channels, with no evidence of fibrosis. Channels created in the myocardium protected the ventricle against an ischemic event when the left anterior descending branch of the coronary artery was ligated. Clinical experience with direct myocardial revascularization by CO2 laser indicates it may be a viable method of treating those patients with ischemic heart disease who are not candidates for other forms of management. The treatment and early postoperative follow-up in one patient are described.     

Reoperation for myocardial revascularization

At The Cleveland Clinic Foundation, reoperations for myocardial revascularization make up 2.7% of all cardiac operations. Major indications for reoperation include: (a) graft failure, (b) progressive atherosclerosis in grafted or ungrafted vessels, (c) previous incomplete revascularization, and (d) combinations of the other 3. Almost one-half of the candidates satisfy more than 1 of the first 3 indications. Although few in number, late graft closure due to atherosclerosis is seen with increasing frequency. Systemic hypothermia coupled with intermittent cold cardioplegia shortens operating time, enhances myocardial protection, and markedly reduces the occurrence of low cardiac output postoperatively. Recent methods of blood conservation and their potential effect on morbidity are discussed. In the first 219 patients operated on through mid-1975, the operative mortality rate was 3.7%, and in subsequent years it was 2%. Although complete relief of angina is achieved less frequently after reoperation, in a follow-up period of 2.5 years, 87% of the 202 surviving patients improved at least one functional class. Relief of angina is virtually the same for each indication category. Those with progressive atherosclerosis had essentially the same clinical result as those operated on for graft failure. A successful result depends on selection of patients with adequate vessel caliber and runoff. Internal mammary artery (IMA) grafting is the procedure of choice for a failed anterior descending vein graft. Although complete revascularization is ideal, many of those who still have perfusion deficits because of diffuse disease can be improved clinically.

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Résumé A la Cleveland Clinic Foundation, les réinterventions de revascularisation myocardique représentent 2.7% de toute la chirurgie cardiaque. Les principales indications de réintervention sont: (a) échec du bypass, (b) artériosclérose progressive des vaisseaux coronaires ou des bypass, (c) revascularisation faite antérieurement mais incomplète, (d) combinasion des 3 premières indications. Près de la moitié des candidats à l'opération répondent à plus d'une des 3 premières indications. La sténose tardive d'un bypass par artériosclérose est actuellement encore relativement rare, mais sa fréquence augmente. L'hypothermie générale avec cardioplégie froide intermittente raccourcit la durée de l'opération, protège le myocarde, et réduit considérablement le risque de défaillance cardiaque postopératoire. Nous discutons les effets possibles, sur la mortalité, des méthodes récentes de conservation sanguine.Pour les 219 premiers malades opérés avant mi1975, la mortalité opératoire était de 3.7%. Pour les années suivantes, elle est de 2%. Bien que les réinterventions ne soulagent pas toujours l'angor, 87% de 202 malades ayant survécu à l'opération et suivis pendant 2.5 ans ont été améliorés d'au moins une classe au point de vue fonctionnel. L'amélioration de l'angor est pratiquement la même pour chaque indication: les résultats cliniques sont similaires chez les malades opérés pour artériosclérose progressive et pour échecs de bypass. La qualité des résultats dépend de la sélection des malades, en particulier du calibre des vaisseaux et de l'état du lit vasculaire en aval des sténoses. Pour les échecs des pontages aorto-coronaires sur la descendante antérieure, l'anastomose mammaire interne est l'opération de choix. La revascularisation complète est, bien sûr, l'idéal; mais nombreux sont les malades cliniquement améliorés malgré des lésions diffuses laissant des déficits de perfusion.

     

Operative technique of myocardial revascularization

With time and experience, improvements in the operative techniques of myocardial revascularization have evolved. Like operations in other areas, the individual preferences of different surgeons play a major role in the selection of the operative procedure or the technical maneuvers to be used. Employment of a systematic approach that encompasses adequate myocardial protection, principles of micro-vascular surgery, precise correction, and complete revascularization has produced an operative mortality rate of less than 1%.

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Résumé Le temps et l'expérience ont amélioré les techniques de revascularisation myocardique. Comme dans toute la chirurgie, le choix de l'opération et des techniques est guidé, en très grande partie, par les préférences individuelles de chaque chirurgien. Avec une technique systématisée comportant une protection efficace du myocarde, des principes de microchirurgie vasculaire, une correction exacte des lésions et une revascularisation complète, la mortalité a été abaissée en-dessous de 1%.