Coronary malperfusion due to type A aortic dissection: mechanism and surgical management

BACKGROUND: Coronary malperfusion associated with aortic dissection is relatively rare, but when it occurs, it is fatal to the patient. To salvage such moribund patients, aggressive coronary revascularization concomitant with aortic repair is essential. We review the surgical results and mechanism of malperfusion in a group of 12 patients with coronary malperfusion caused by type A aortic dissection, and we discuss our surgical approach. METHODS: Between March 1990 and March 2003, 12 patients (6.1%) from a total of 196 consecutive patients with acute type A aortic dissection undergoing surgery suffered coronary malperfusion associated with the dissection. There were 4 men and 8 women (mean age, 60.8 +/- 8.3 years). Nine patients had acute myocardial infarction due to dissection before surgery, and 3 patients suffered coronary malperfusion after aortic declamping. RESULTS: Hospital mortality rate was 33.3% (4 patients). The mortality rate was higher than that in patients without coronary malperfusion (33.3% vs. 8.2%, p = 0.019). Three patients could not be weaned from cardiopulmonary bypass, and 1 patient died of heart failure in the intensive care unit. Involved coronary arteries included the right coronary artery (8 patients), left coronary (2 patients), and both (2 patients). Mechanisms of coronary obstruction were compression (2 patients), coronary dissection (7 patients), and coronary disruption (3 patients). Coronary artery bypass grafting was performed concomitant with aortic repair. CONCLUSIONS: Acute type A aortic dissection with coronary involvement is associated with high mortality rate, aggressive coronary revascularization and early aortic repair with simple techniques are necessary to salvage these critically ill patients.     

Technique and results with a roller pump left and right heart assist device

During the last 10 years we have inserted a roller pump-driven left heart assist device in 72 patients and a right heart assist device in 7 patients for profound heart failure after a variety of cardiac surgical procedures. In addition a percutaneous left heart assist device (transseptal insertion of left atrial cannula via a femoral vein) was employed in 5 patients with profound cardiogenic shock after acute myocardial infarction. Thirty patients (41.7%) were weaned from the left heart assist device and 21 (29.2%) were discharged from the hospital. Two patients (40.0%) were weaned from the right heart assist device, but both later died during the postoperative period. Of the 5 patients in whom a percutaneous left heart assist device was inserted, 4 underwent successful emergency percutaneous transluminal coronary angioplasty, but all 5 patients died. Causes of death included severe coagulopathy, irreversible extensive myocardial infarction and cardiac failure, refractory arrhythmias, severe "shock" lung, and multisystem failure. In summary, satisfactory results can be achieved with a roller pump-driven left and right heart assist device for severe postoperative heart failure. Further experience should be obtained with the percutaneous technique to assess its efficacy in treating patients with acute myocardial infarction and cardiogenic shock.     

Beating-Heart Coronary Artery Bypass Grafting for Left Ventricular Failure Assisted by the Abiomed BVS 5000

Two cases of postmyocardial infarction cardiogenic shock were treated with left ventricular assist device (LVAD) implantation. With the left ventricular function bypassed, beating-heart coronary artery bypass grafting (CABG) was performed. This technique may be useful in the setting of acute myocardial dysfunction where limited coronary revascularization is required.     

Oxygen consumption of the normal and failing heart during left heart bypass.

In order to determine whether myocardial oxygen consumption (MOC) is decreased during left heart bypass (LHB), two groups of 6 dogs each were subjected to 2 hours of heparinless LHB. Group 2 differed from Group 1 in that cardiogenic shock was induced by temporary coronary artery occlusion prior to LHB. In Group 1 animals (normal dogs), MOC decreased significantly during the surgical preparation but did not change appreciably during subsequent LHB. Upon completion of LHB, MOC increased slightly in all animals. This increase in MOC was insignificant, however, when adjusted to changes in mean aortic blood pressure (MAP). A highly positive linear correlation between MOC and MAP was noted regardless of whether the animals were on or off bypass. In Group 2 animals, MOC was markedly decreased after the iduction of cardiogenic shock but gradually increased during the 2 hours of LHB. Upon completion of bypass, MOC of the damaged heart increased to a remarkable degree, but not to initial control levels. However, the linear correlation between MOC and MAP, noted before the induction of cardiogenic shock, disappeared after shock and was not restored after 2 hours of apparently successful bypass. We have concluded that MOC is decreased surgical stress and is further decreased by temporary coronary artery occlusion. MOC is not, however, reduced by nearly total or total LHB in normal hearts. MOC is markedly decreased by cardiac damage but gradually increases in damaged hearts by the use of LHB.     

Mechanical Circulatory Support for Severe Heart Failure After Operation

To evaluate the clinical results of circulatory support for severe heart failure after operation, we examined 62 patients (39 males and 23 females) who underwent circulatory support for postoperative heart failure from 1984 to 1996. Their ages ranged from 22 to 78 (mean 52) years. In 62 patients, 35 had valvular, 25 had ischemic, and 2 had congenital heart disease. Postoperation, 29 patients underwent venoarterial bypass (VAB), 20 had biventricular bypass (BVB), and 8 had left ventricular bypass (LVB). The remaining 5 patients received a pulsatile left ventricular assist device (LVAD). The weaning and discharge rates of the patients by type of support were 51.7% and 31.0% with VAB, 75.0% and 55.0% with BVB, 87.5% and 37.5% with LVB, and 60.0% and 40.0% with LVAD, respectively. The complete results of this series (64.5% weaning rate and 40.3% discharge rate) were acceptable.     

Cardiac surgery for patients with ventricular dysfunction

Coronary artery disease and aortic stenosis/regurgitation may cause irreversible myocardial damage, resulting in significant heart failure. Although the ultimate treatment of the end-stage heart failure is heart transplantation or ventricular assist devices, in most cases these patients still have some amount of functional and survival benefit by simple surgical treatment such as coronary artery bypass grafting (CABG) and valve replacement. However it is associated with significant perioperative mortality and morbidity.     

Analysis of Clinical Factors for Survival After Left and Biventricular Bypass Using Centrifugal Pump Following Open Heart Surgery in Infants and Adults

A total of eight patients, including three infants, received left or biventricular assist using centrifugal pump (CFP) following open heart surgery. Three infants, aged 9-11 months and with complex cardiac lesions, were supported by left heart bypass (LHB) using pediatric type CFP for 63 h, 64 h, and 13 days. All were weaned from LHB, but long-term survival was not obtained, mainly due to complications. In five adult patients, LHB alone was used in three, and biventricular support in two for 33-240 h with three survivals. The factors related to unsuccessful recovery were delayed start of support and multiorgan failure.     

Heartmate II Implantation with Right Coronary Bypass Grafting in Ischemic Cardiomyopathy with "Fixed" Pulmonary Hypertension: Treatment Strategy to Protect Right Ventricular Function

Abstract   A 49-year-old male patient suffering from end-stage ischemic cardiomyopathy with a left ventricular ejection fraction below 15% was presented to redo coronary artery bypass grafting (CABG). Coronary angiogram demonstrated an occluded left anterior descending artery and occluded right coronary artery, perfused retrogradely from the circumflex artery. Since positron emission tomography did not demonstrate viable left ventricular myocardium except for the basis of the left ventricle, CABG was considered futile. Cardiac transplantation was contra-indicated due to pharmacologically unresponsive pulmonary artery hypertension. The patient successfully underwent left ventricular assist device implantation in combination with right coronary artery revascularization. The article reflects the regimen of right ventricular preservation in this patient. (J Card Surg 2010;25:116-119)     

Multivessel distal sutureless off-pump coronary artery bypass grafting procedure using magnetic connectors

Proximal anastomotic devices for beating heart coronary artery bypass grafting (CABG) have been developed to avoid ascending aortic manipulation. Distal anastomotic devices may become an extremely useful tool to assist in enabling minimally invasive (robotic) multivessel CABG. As a transition phase toward this ultimate goal we have been using a distal anastomotic device for the left internal mammary artery-left anterior descending artery (LIMA-LAD) anastomosis. In addition we recently performed two off-pump coronary artery bypass procedures that were distally completely sutureless.     

A case of successful emergency coronary artery bypass grafting surgery for failed coronary angioplasty using percutaneous cardiopulmonary support]

This is the first Japanese case of the successful emergency coronary artery bypass grafting (CABG) surgery for failed percutaneous transluminal coronary angioplasty (PTCA) using percutaneous cardiopulmonary support (PCPS). A 81-year-old woman with old myocardial infarction and angina pectoris is presented. Her coronary angiogram showed the 90% and 50% stenosis of the right coronary artery (RCA) and the total occlusion of the left anterior descending artery (LAD). PTCA for the 90% stenosis of RCA was performed. But, during the balloon dilation, her heart rate and blood pressure decreased. PTCA was stopped. As her chest pain was worse, re-PTCA was tried, using PCPS. Under PCPS (3 l/min), the balloon dilation was performed safely and smoothly. But, the unexpected dissection of RCA occurred, and became larger rapidly. After 85 minutes, the emergency CABG was performed. By using PCPS, the stable hemodynamics was given till the operation. CABG to RCA and LAD was performed safely. After the surgery, the patient progressed well. PCPS was a very useful cardiopulmonary assist device.     

Evaluation of right ventricular function by intraoperative transesophageal echocardiography for patients with left ventricular dysfunction

We evaluated right and left ventricular function by intraoperative transesophageal echocardiography for the patients with left ventricular dysfunction (left ventricular ejection fraction (LVEF) < or = 40) who underwent isolated coronary artery bypass grafting (CABG). We divided these patients into two groups; group 1 who had difficulty of weaning from cardiopulmonary bypass due to hypotension (n = 8) and group 2 who did not have any difficulty of it (n = 17). Basement characteristics (age, gender, history of myocardial infarction, congestive heart failure, LVEF, severity of the right coronary artery disease) of both groups were not different significantly. Intraoperative characteristics (the number of distal anastomoses, duration of aortic cross-clamp and cardiopulmonary bypass, and bypass to the right coronary artery) were also not different between two groups. However, mean duration of ICU stay and in-hospital mortality were significantly longer and higher in group 1 than group 2. On the other hand, right ventricular systolic function was severely impaired, particularly postoperatively, in group 1 compared with group 2. Right and left ventricular systolic function of group 2 was fairly improved postoperatively. These results may indicate that right ventricular dysfunction is a potent predictor of postoperative morbidity and mortality for the patients with left ventricular dysfunction who undergo isolated CABG.     

Myocardial revascularization without extracorporeal circulation

Contemporary treatment of coronary disease includes: drug treatment, percutaneous coronary angioplasty (PCI), with or without stent implantation and surgical myocardial revascularization. For more than 30 years, conventional coronary bypass (on-pump CABG), using cardiopulmonary bypass (CPB), represented the standard regarding myocardial revascularization, particularly in patients suffering from three vessel disease or left main coronary artery stenosis. Recent development of invasive cardiology and increased interest in coronary surgery on the beating heart (OPCAB), challenging traditional on-pump CABG procedure, as optimal strategy for the treatment of coronary artery disease. In order to improve clinical outcome, OPCAB seems to be a good choice in patients with co-morbidities critical for use of CPB. Results of OPCAB revascularization in general patient population are considerably different and require further evaluation. This review article shows the development of OPCAB and elaborates potential advantages and weaknesses of this method of revascularization, from both, theoretical and clinical point of view, compared to standard surgical myocardial revascularization.     

Ischemia of the interventricular septum. A mechanism of right ventricular failure during mechanical left ventricular assist.

Right ventricular failure has been noted in up to 25% of patients requiring a left ventricular assist device. Altered septal motion or function is one proposed mechanism of right ventricular failure during left heart bypass. We studied the effect of regional ischemia and reperfusion of the interventricular septum on right ventricular function during complete left heart bypass. In six calves the septal perforating branches of the proximal left anterior descending coronary artery were isolated for intermittent occlusion. Complete left heart bypass was established with a Pierce-Donachy left ventricular assist device. Right and left ventricular function were studied with two-dimensional echocardiography and with intraventricular pressure monitors. Establishment of left heart bypass did not significantly affect right ventricular developed pressure, right ventricular end-diastolic area, or right ventricular fractional change in area. Left heart bypass significantly (p less than 0.001) decreased percent systolic septal wall thickening. Septal ischemia during left heart bypass resulted in a decrease in right ventricular developed pressure (p = 0.09), significant increase in right ventricular end-diastolic area (p = 0.002) and significant decrease in right ventricular fractional change in area (p less than 0.001), and a further decrease in interventricular septal wall thickening (p = 0.016). The interventricular septum became thin with flattening of its normal contour. Septal reperfusion resulted in right ventricular recovery with significant improvement in all factors (p less than 0.02). Similar results were documented during a second episode of septal ischemia with recovery after septal reperfusion. In some cases, septal ischemia may be an important factor in the development of right ventricular failure during left heart bypass.     

Feasibility and safety of autologous myoblast transplantation in patients with ischemic cardiomyopathy

Successful autologous skeletal myoblast transplantation into infarcted myocardium in a variety of animal models has demonstrated improvement in cardiac function. We evaluated the safety and feasibility of transplanting autologous myoblasts into infarcted myocardium of patients undergoing concurrent coronary artery bypass grafting (CABG) or left ventricular assist device implantation (LVAD). In addition, we sought to gain preliminary information on graft survival and any potential improvement of cardiac function. Eighteen patients with a history of ischemic cardiomyopathy participated in a phase I, nonrandomized, multicenter pilot study of autologous skeletal myoblast transplantation concurrent with CABG or LVAD implantation. Twelve patients with a history of previous myocardial infarction (MI) and a left ventricular ejection of less than 30% were enrolled in the CABG arm. In a second arm, six patients underwent LVAD implantation as a bridge to heart transplantation and were required to donate their heart for testing at the time of heart transplant. Myoblasts were successfully transplanted in all patients without any acute injection-related complications or significant long-term unexpected adverse events. Follow-up PET scans showed new areas of viability within the infarct scar in CABG patients. Echocardiography measured an average improvement in left ventricular ejection fraction (LVEF) from 25% to 34%. Histological evaluation in four out of five patients who underwent heart transplantation documented survival and engraftment of the skeletal myoblasts within the infarcted myocardium. These interim results demonstrate survival, feasibility, and safety of autologous myoblast transplantation and suggest that this modality may offer a potential therapeutic treatment for end-stage heart disease.     

老年人非体外循环冠状动脉旁路移植术的心肌保护作用

目的比较70岁以上老年人非体外循环冠状动脉旁路移植术(OPCAB)和体外循环冠状动脉旁路移植术(CABG)围术期心肌损伤程度,探讨OPCAB的心肌保护效果。方法30例老年患者分为两组,A组15例,为CABG组,B组15例,为OPCAB组。分别于术前、术中30min、术中1h、术后6h、12h、24h、72h、120h取静脉血标本,分别测定心肌肌钙蛋白I(cTnI)水平和CKMB活性;另外记录围手术期各项临床指标。结果OPCAB组术后辅助呼吸时间较CABG组短(P<0.01),而且主动脉球囊反搏和输血例数较低(P<0.05)。CABG组与OPCAB组cTnI、CKMB的术前水平相,术后6hcTnI即有升高而后下降,术后30min至72h均较OPCAB组明显升高(P<0.05或0.01)。结论与CABG相比,OPCAB的心肌损伤较轻,心肌保护效果较好。     

Overview: Japanese guidelines for myocardial revascularization to treat stable ischemic heart disease 2012

Since its introduction in the early 1970s, coronary artery bypass grafting (CABG) has become an established surgical treatment for coronary artery disease (CAD). Percutaneous coronary intervention (PCI), first clinically applied in 1977, was promoted as an alternative to CABG during the mid-1980s. Along with the nationwide expansion of PCI, the ratio of PCI to CABG has exceeded 6–7:1. The Japanese Circulation Society (JCS) published “Guidelines on elective coronary intervention, including coronary artery bypass grafting (CABG), for ischemic heart disease in 2000” and “Guidelines on the selection of bypass conduits and operative procedures in coronary artery bypass grafting for ischemic heart disease”. The society intended to revise these guidelines in 2010 and to issue two new guidelines specific either to PCI or CABG. They also planned to issue joint guidelines for myocardial revascularization and PCI/CABG, which are primary indications for patients with stable CAD, especially with those with more complex left main trunk disease and/or multi-vessel disease. The scientific committee of JCS established the “Council for myocardial revascularization” that consisted of experts including interventional and non-interventional cardiologists, cardiac surgeons and physicians specialized in diabetes or nephrology selected by medical and surgical societies. After over 10 rounds of meetings, the Council prepared primary guidelines for myocardial revascularization to treat stable CAD, PCI/CABG. These guidelines consist of (1) Statements about myocardial revascularization, (2) Interpretation of the statements and (3) Indications for PCI/CABG including a table.     

Coronary Microcirculation During Left Heart Bypass with a Centrifugal Pump

Abstract: To estimate coronary microcirculation during left heart bypass (LHB), we performed an experimental comparison study of LHB and intraaortic balloon pumping (1ABP). LHB was performed with a BioMedicus BP-80 pump supporting half of the flow of cardiac output whereas the IABP was pumped in a 1:1 mode for cardiogenic shock in a swine model. Coronary circulations were analyzed by electromagnetic flowmeter, pulsed Doppler velocimeter, and laser Doppler flowmeter. Left ventricular end-diastolic pressure (LVEDP) was reduced significantly by LHB. Although there was no significant difference in epicardial flow between the LHB and IABP groups, endocardial flow was increased significantly by LHB. In the LHB group, the systolic reverse wave of the coronary velocity called a myocardial invalid circulation was reduced remarkably. There was a significant inverse correlation between endocardial flow and LVEDP. These results suggested that LHB was more effective for myocardial microcirculation than was IABP.     

Experience of coronary artery bypass grafting on the beating heart with right heart bypass; 3 cases of octogenarian

Right heart bypass (RHB) yields more stable hemodynamics by increasing left ventricular preload and collapse right ventricular chamber during the displacement of the heart on beating heart coronary artery bypass grafting (CABG). Recently beating heart CABG gaining popularity, and the indications for CABG have increasingly expanded to elderly person. Using RHB while exposing posterior branches by displacing the beating heart, we have attempted to make total revascularization in beating heart CABG. We performed beating heart CABG with RHB in 3 cases of octogenarian. All patients had left main trunk lesion and needed revascularization of posterior vessels. Introduction of RHB enabled us to approach to posterior target vessels in better exposure and under greater hemodynamic stability. All three patients had no complications postoperatively. Strictly speaking CABG with RHB is not off-pump CABG, but RHB system does not include either artificial lung or manipulation of the aorta. Therefore we think it is very effective support system which enables multiple coronary revascularization for elderly person.     

The beating open heart for rebuilding ventricular geometry during surgical anterior restoration

Heart failure is an increasing problem because of successful therapies in younger age groups and an overall increase in age in the general population. Ischemic cardiomyopathy secondary to myocardial infarction is the most prevalent entity among the several causes for cardiac failure. Among the surgical options for these patients, neither transplantation nor current ventricular assist devices are able to treat a sufficient number of patients. Ventricular restoration, however, may evolve as a surgical option to treat myocardial failure secondary to postinfarction ventricular dilatation. This procedure must be undertaken in high-risk coronary artery bypass graft (CABG) patients in heart failure. We describe the techniques for both the conventional procedure (CABG +/- mitral valve [MV] repair) using cardioplegic methods, and the beating open heart for surgical anterior ventricular restoration (SAVR) for dyskinetic and akinetic areas in ischemic cardiomyopathies. This combined approach allows safe restoration of the ventricular geometry with minimal use of mechanical support (ie, intra-aortic balloon pump [IABP]) in 195 consecutive patients undergoing this procedure by members of an international team called the RESTORE group.     

Effect of Synchronous and Asynchronous Pulsatile Flow During Left, Right, and Biventricular Bypass

Ventricular assist devices augment flow from the left atrium to the aorta and/or from the right atrium to the pulmonary artery. Most devices are used in the asynchronous full-to-empty mode (asynchronous) but may also be used in a synchronous counterpulsation mode (synchronous). This study determines the optimal assist modes to reduce myocardial oxygen consumption (MVO2) and metabolism. Twelve pigs were instrumented with carotid artery and Baim coronary sinus catheters for determination of MVO2 and myocardial lactate production (LACT). Six were implanted with a Pierce-Donachy left ventricular assist device (LVAD) and 6 with both right and left ventricular assist devices (BIVAD). Two periods each of control, synchronous, and asynchronous bypass were instituted, the midanterior descending coronary artery (LAD) was ligated, and the sequence was repeated. After each period, MVO2 and LACT were determined and myocardial biopsy specimens were obtained for tissue, lactate, and ATP assay. Following LAD ligation, biopsy specimens were obtained from both the infarct and noninfarct zones of the heart. MVO2 decreased (p < 0.05) in the asynchronous BIVAD mode compared with control. MVO2 was unchanged in synchronous BIVAD or either LVAD mode. Tissue ATP and tissue lactate were unaffected by any mode of bypass. Only BIVAD in the asynchronous mode reduced MVO2. When ventricular assist devices are utilized to aid recovery of the natural heart, two devices should always be inserted to allow biventricular assist. Synchronous counterpulsation offers no advantage.