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.     

激光血运重建术治疗冠心病的临床研究

目的:总结分析了99年9月至99年11月激光血运重建术治疗冠心病3例的临床经验。资料及方法:3例冠心病患者均为不稳定性心绞痛,有阵旧性心肌梗塞1例,3例均合并Ⅱ期高血压病。超声心动图左室射血分数在0.57～0.62之间,FS 0.28～0.30。经心肌核素扫描99~M(Ti—MiBi)及心电图检查均提示前壁及下壁缺血。在全麻下经左胸前外侧第5肋间进胸,显露左心室壁,采用高功率二氧化碳激光打孔器(梅曼公司HL-100型)在左室缺血区域打孔8～14个。结果:3例病人术后2周全部康复出院,术后无心律失常,无心衰及心肌梗塞,术后心绞痛症状均全部缓解,一般体力活动不受限制。结论:激光血运重建术治疗冠心病是安全、有效的,对于国人由于冠状动脉血管纤细,激光血远重建术适应证可适当放宽。     

支架植入术治疗外伤性冠状动脉夹层并血栓形成致急性心肌梗死1例

患者男,63岁,车祸后全身多处(心前区、右上肢、右下肢及左上肢)疼痛1 h余,伴呼吸困难、全身大汗淋漓、心悸;既往无心脏病、糖尿病、脑血管病史。查体:右上肢、右下肢及左上肢关节活动障碍,右下肢皮下软组织肿胀、瘀青。心电图示V2导联异常Q波,V2、V3导联ST段抬高,Ⅱ、V5、V6导联ST段压低;诊断:前间壁急性心肌梗死。实验室检查:白细胞计数22.59×10⁹/L,D-二聚体13.76μg/ml,纤维蛋白原降解产物50.28μg/ml,降钙素原0.056 ng/ml,超敏肌钙蛋白Ⅰ0.204 ng/ml,肌红蛋白>1000.00 ng/ml,肌酸激酶MB亚型25.13 ng/ml。     

Angiogenesis three months after clinical transmyocardial laser revascularization using an excimer laser.

BACKGROUND AND OBJECTIVE: We present for the first time histologic findings 3 months after clinical transmyocardial laser revascularization using a XeCl excimer laser. STUDY DESIGN/MATERIALS AND METHODS: Histology was performed on a patient who died from a noncardiac cause 3 months post-excimer TMLR. RESULTS: In the treated myocardium, no patent channels were found but scars were seen with a linear distribution and in continuity with circumscribed small fibrotic endocardial and epicardial scars. The scars were highly vascularized by new vessels, ranging from small capillaries to large thin walled, and sometimes branching ectatic vessels. Sprouting of vessels into the adjacent myocardium was also observed. CONCLUSION: These results suggest that angiogenesis might play a role in the clinical improvement after TMLR.     

Volumetric preload measurement by thermodilution: a comparison with transoesophageal echocardiography

Background. End-diastolic volume indices determined by transpulmonarythermodilution and pulmonary artery thermodilution may givea better estimate of left ventricular preload than pulmonarycapillary wedge pressure monitoring. The aim of this study wasto compare volume preload monitoring using the two differentthermodilution techniques with left ventricular preload assessmentby transoesophageal echocardiography (TOE). Methods. Twenty patients undergoing elective cardiac surgerywith preserved left–right ventricular function were studiedafter induction of anaesthesia. Conventional haemodynamic variables,global end-diastolic volume index using the pulse contour cardiacoutput (PiCCO) system (GEDVI_PiCCO), continuous end-diastolicvolume index (CEDVI_PAC) measured by a modified pulmonary arterycatheter (PAC), left ventricular end-diastolic area index (LVEDAI)using TOE and stroke volume indices (SVI) were recorded beforeand 20 and 40 min after fluid replacement therapy. Analysisof variance (Bonferroni–Dunn), Bland–Altman analysisand linear regression were performed. Results. GEDVI_PiCCO, CEDVI_PAC, LVEDAI and SVI_PiCCO/PAC increasedsignificantly after fluid load (P<0.05). An increase >10%for GEDVI_PiCCO and LVEDAI was observed in 85% and 90% of thepatients compared with 45% for CEDVI_PAC. Mean bias (2 SD) betweenpercentage changes (     

Aortic connector for coronary revascularization in a patient with Takayasu''s disease

Takayasu's disease affects the aorta and its major branches including coronary arteries, some of which may require coronary artery bypass grafting (CABG). However, calcification of the aorta affected by Takayasu's disease often makes proximal anastomosis of a vein graft very difficult. In addition, since the major branches of the aortic arch are also frequently affected by it, the internal mammary arteries are unsuitable for use in CABG. We report a 60-year-old woman with stenosis of the left main coronary artery and heavy aortic calcification caused by Takayasu's disease whose severe angina was successfully relieved by off-pump CABG using mechanical aortic connectors for proximal vein graft anastomoses.     

Intramyocardial partial oxygen pressure in patients undergoing transmyocardial laser revascularization and bypass surgery

Objective—Numerous investigations could not clarify the exact mechanism of transmyocardial laser revascularization (TMLR). The aim of this study was to investigate, whether TMLR leads to an increase of myocardial oxygenation in comparison to patients undergoing coronary artery bypass grafting (CABG).

Design—Twelve patients (TMLR group) underwent TMLR alone with an 800?W CO ₂ laser through a left anterior thoracotomy. Seventeen patients (CABG group) underwent standard CABG. Myocardial oxygenation was determined by measuring intramyocardial partial oxygen pressure (p _ti O ₂ ). P _ti O ₂ was measured online and mean values at 1,?24,?32, and 48?h postoperatively were compared with baseline before intervention. Parameters influencing p _ti O ₂ (arterial pO ₂ , hemodynamic parameters, hemoglobin) were recorded.

Results—Mean baseline p _ti O ₂ was significantly lower in the TMLR group compared with the CABG group (p?<?0.05). In both groups p _ti O ₂ increased significantly in the postoperative course, whereby p _ti O ₂ in the TMLR group was significantly lower compared with the CABG group.

Conclusion—Although the exact mechanism of action of TMLR remains unclear, p _ti O ₂ and thus oxygen supply in the myocardium increased in patients undergoing TMLR at least in the early postoperative course. However, p _ti O ₂ increased to a lesser extent compared with CABG.     

Off-pump multivessel revascularization

Objective: Off-pump coronary artery bypass grafting (CABG) has come into widespread use with the availability adequate coronary stabilization devices. We studied the efficacy of second-generation coronary stabilization devices (suction device) comparing to the first-generation device (compression device). Methods: We prospectively analyzed consecutive patients who underwent isolated off-pump CABG via a midline sternotomy at Shin-Tokyo Hospital Group between July 1, 1996, and August 31, 2000, comparing perioperative, and follow-up data in the group using a suction device (group S) to that in the group using a compression device (group C). Results: Preoperative risk factors were identical between the two groups, with the exception of a higher incidence of three vessel disease in group S. Complete revascularization increased from 47.3% in group C to 88.1% in group S, and the number of distal anastomoses from 2.1±0.6 in group C to 2.9±0.9 in group S. Revascularization of the circumflex artery was achieved in 21.7% of group S patients, which was significantly higher than that in group C (2.2%). Postoperative recovery, mortality, and morbidity did not differ significantly between groups. Calculated event-free rates at 2 years was 88.7% in group C and 92.0% in group S (p=NS). Conclusions: Anastomosis to the posterior wall of the heart using the suction device is safe. An increased number of distal anastomoses may reduce the occurrence of cardiac events related to incomplete revascularization.     

Double-vessel revascularization using a composite graft approached from small left thoracotomy

Minimally invasive direct coronary artery bypass usually includes single vessel revascularization via a small skin incision. In most cases, the left internal mammary artery has been used for bypassing to the left anterior descending artery, and only single vessel revascularization used to be performed due to the limited operating field. We present 2 cases of successful double-vessel revascularization approached from a left small thoracotomy, using a composite graft of the internal mammary artery and the inferior epigastric artery, anastomosing to the left anterior descending artery and diagonal artery.     

Transventricular revascularization by Laser

Transventricular acupuncture or revascularization by the method of producing channels between the ventricular cavity and the ischemic myocardium has challenged several investigators. The concept of producing these channels using high-energy CO₂ laser was based on the finding that the laser beam could produce small channels devoid of debris, and fibrosis would not occur. Four groups of mongrel dogs with six animals in each group were studied. In three groups the left anterior descending (LAD) branch of the coronary arteries was ligated above the first diagonal, and channels were made in the myocardium according to the protocol for each group. The fourth group was the control, the LAD was ligated but the myocardium was not exposed to laser treatment. In the control group all animals died within 20 minutes of LAD ligation. Animals in the other groups survived ligation with laser, and were subsequently sacrificed at varying intervals. At autopsy the epicardial component of the channels was visible. Penetration through the myocardium could be demonstrated. Microscopically the channels were patent and endothelialized. Further investigations are in process, but we believe laser channels protect and nourish the ischemic myocardium.     

Multivessel coronary revascularization and outcomes in kidney transplant recipients

Coronary artery disease is a major cause of morbidity and mortality in the kidney transplant population. We compared the long‐term outcomes of coronary artery bypass graft (CABG) surgery with percutaneous coronary intervention (PCI) for multivessel coronary disease in a contemporary cohort of US kidney transplant recipients. From the U.S. Renal Data System, we identified all adult kidney transplant patients with ≥6 months of Medicare A+B undergoing first recorded multivessel coronary revascularization from 1997 to 2009. The associations of CABG versus PCI with death and the composite of death or myocardial infarction (MI) were compared using proportional hazards regression. Of the 2272 patients included in the study, 1594 underwent CABG and 678 underwent PCI. The estimated 5‐year survival rate was 55% [95% confidence interval (CI) 53% to 57%] following coronary revascularization, with no significant association between revascularization type and death [adjusted hazard ratio (aHR) = 1.08; CI 0.94–1.23] or the composite of death or MI (aHR = 1.07; CI 0.96–1.18). Separate propensity score‐matched analyses yielded similar results. In this analysis of kidney transplant recipients undergoing multivessel coronary revascularization, we found no difference between CABG and PCI in terms of survival or the composite of death and MI.     

Surgeons should be wise when choosing a material to repair heart defects

Various types of prosthetic materials are available for usage in cardiac surgery to repair heart defects. PTFE, Dacron, and bovine pericardial are some examples of the most used materials for this purpose. In this article, the authors describe the potential failure of the CorMatrix®.     

Surgical Treatment for Ischemic Heart Failure (STICH) trial: A review of outcomes

Coronary artery disease (CAD) is a significant source of morbidity and mortality in developed countries. The landmark Surgical Treatment for Ischemic Heart Failure (STICH) trial has provided greatly needed evidence in the management of patients with severe left ventricle (LV) dysfunction (LVEF ≤ 35%) and CAD amenable to revascularization. The trial investigated two primary hypotheses: (i) that coronary artery bypass grafting (CABG) with optimal medical therapy (OMT) was superior to OMT alone, and (ii) that CABG with surgical ventricular reconstruction (SVR) would be superior to CABG alone. The results of the 10‐year follow‐up demonstrated significant long‐term benefits with the addition of CABG to OMT. However, the second hypothesis yielded controversial results as the study found no difference between CABG with SVR and SVR alone. The STICH trial, and the numerous subanalyses that followed have reinforced and challenged a number of widely held beliefs regarding the management of patients with severe LV dysfunction and ischemic heart failure. The purpose of this comprehensive review is to outline the published data from the STICH trial and its substudies while providing a balanced assessment of the evidence‐based conclusions and criticisms that have followed.     

冠状动脉旁路术同期瓣膜手术的体会

目的 介绍冠状动脉旁路术(CABG)同时行心脏瓣膜手术的体会。方法 45例患者,平均年龄59岁(42～75岁);心功能(NYHA)Ⅱ级7例、Ⅲ级30例、Ⅳ级8例;二尖瓣病变30例、主动脉病变7例、联合瓣膜病变8例,均伴有单支或多支冠状动脉病变。手术在中度低温体外循环下完成。心脏停跳后,先作静脉桥的远端吻合,然后置换瓣膜。心脏复苏后完成大隐静脉与升主动脉的吻合,或在升主动脉1次阻断下完成。乳内动脉的吻合在换瓣后心脏复苏前完成。本组6例行二尖瓣成形,31例行机械瓣置换,8例行进口生物瓣置换。结果 本组患者无手术死亡。术后呼吸机使用时间平均18．7h,ICU监护1．8d。住院时间平均9．2d。随访6个月～4年患者无死亡,心功能Ⅰ级35例、Ⅱ级10例。结论 冠状动脉旁路移植术同时行瓣膜手术是安全、有效的。