Perioperative enoximone infusion improves cardiac enzyme release after CABG

OBJECTIVE: To assess whether routine postoperative enoximone infusion compared with dobutamine improved clinical and biochemical results after coronary artery bypass grafting with cardiopulmonary bypass. DESIGN: Prospective nonrandomized study. Data collection was blinded to the choice of inotrope. SETTING: Double-institutional clinical investigation. PARTICIPANTS: Two hundred sixteen consecutive patients undergoing myocardial revascularization between May 2000 and December 2002. INTERVENTIONS: Seventy-two patients underwent myocardial revascularization and were treated with enoximone, 5 microg/kg/min (group A). They were compared in a ratio of 1:2 to 144 patients treated with dobutamine at the same dose (group B) after aortic cross-clamp removal. The groups proved to be homogenous in preoperative and intraoperative characteristics. MEASUREMENTS and MAIN RESULTS: Hospital outcome, electrocardiogram, echocardiography, further inotropic support, and biochemical markers of ischemia were compared. Subsets of patients with comorbidities and total arterial revascularization were analyzed. Perioperative myocardial infarction, postoperative low-output syndrome, intra-aortic balloon pump, atrial fibrillation, ST-segment changes, postoperative echocardiographic findings, and intensive care and hospital durations were similar between groups. In the postoperative course, more patients belonging to group A maintained low-dose inotropic support, whereas more patients belonging to group B required higher doses. Troponin I and creatine kinase-MB values were higher in patients of group B, especially when subgroups with diabetes, left ventricular hypertrophy, or total arterial revascularization were included. CONCLUSION: Postoperative enoximone reduced troponin I release and need for inotropic support in patients undergoing on-pump myocardial revascularization. Subgroup data were confirmed in diabetes, left ventricular hypertrophy, and total arterial revascularization.     

Myocardial perfusion correlates with improvement of systolic function of the left ventricle after CABG. Dobutamine echocardiography and Tc-99m-MIBI SPECT study.

OBJECTIVE: The aim of the study was to assess the effect of surgical revascularization [coronary artery bypass grafting (CABG)] on systolic function and perfusion of the left ventricle using dobutamine echocardiography (DE) and Tc-99m-MIBI SPECT (SPECT). METHODS: There were 32 patients mean age 52.2+/-7.2 years in whom DE and SPECT were performed before and 3-4 months after CABG using standard protocols. Wall motion score index (WMSI) and perfusion index (PI) were calculated. RESULTS: Significant improvement of WMSI at rest (1.44+/-0.46 vs 1.33+/-0.41; P=0.03) as well as after maximal dose of dobutamine (1.49+/-0.42 vs 1.39+/-0.44; P=0.02) was observed after CABG as compared to preoperative examination. Similar relation was observed during SPECT study. Perfusion index diminished significantly after revascularization during rest acquisition (2.19+/-0.71 vs 1.93+/-0.70; P=0.0008) and after Dipirydamole administration (2.73+/-0.73 vs 2.20+/-0.69; P=0.0001) as compared to preoperative examination. We found correlation between PI and WMSI at rest before CABG (R=0.46; P=0.01), PI after Dipirydamole and WMSI after maximal dose of Dobutamine before CABG (R=0.37; P=0.04), PI and WMSI at rest after CABG (R=0.39; P=0.03), PI after Dipirydamole and WMSI after dobutamine after CABG (R=0.38; P=0.03). CONCLUSIONS: Surgical revascularization significantly improves both perfusion and contractility. Increased perfusion after CABG correlates with improvement of systolic function of the left ventricle.     

Quantitative analysis of myocardial revascularization on left ventricular diastolic function

To evaluate the effects of myocardial revascularization on left ventricular diastolic function, we studied three groups of subjects. Group I consisted of 10 patients without any previous myocardial infarction. Group II consisted of 10 patients with previous myocardial infarction. The control group consisted of 8 normal subjects, all with no evidence of cardiac disease as determined by cardiac catheterization. Left ventricular diastolic function was assessed by maximum negative dp/dt, constant T, diastolic compliance and 1/3 fractional filling before and after surgical revascularization. (1) Constant T, maximum negative dp/dt and diastolic compliance: There was no significant difference among groups I, II and the control group preoperatively, and the variables were not improved postoperatively. (2) 1/3 fractional filling: 1/3 fractional fillings in groups I and II were significantly lower (p less than 0.05, p less than 0.01) than the control group preoperatively, and it was significantly improved in group I, but unchanged in group II postoperatively. In conclusion, myocardial revascularization improves left ventricular diastolic function in the patients without previous myocardial infarction. The effects of myocardial revascularization, however, in the patients with prior myocardial infarction do not bring about an enhancement of left ventricular diastolic function.     

Wall motion and perfusion analysis of transmyocardial laser revascularization

OBJECTIVE: Transmyocardial laser revascularization (TMLR) creates channels in the myocardium. The aim of the treatment is to relieve angina in patients with end-stage coronary artery disease. We studied the effect of TMLR on myocardial function and perfusion with the combination of cine magnetic resonance imaging (MRI) and thallium scintigraphy. DESIGN: Eight patients with severe triple-vessel coronary artery disease were studied with MRI and thallium scintigraphy before and 6 months after laser treatment. RESULTS: TMLR did not improve global left ventricular (LV) function or myocardial perfusion. However, systolic wall thickening deprived in segments with fixed perfusion defects in 6 months and laser treatment prevented this deprivation (p = 0.03). In addition single photon emission computed tomography (SPECT) imaging indicated that TMLR prevented conversion of reversible into fixed defects. CONCLUSION: In severe, progressing coronary artery disease TMLR does not improve global LV function or myocardial perfusion, but it preserves systolic wall thickening in fixed defects (scar). It also prevents changes from ischemic myocardial regions to scar.     

Functional comparison of transmyocardial revascularization by mechanical and laser means

Background. As a result of the clinical benefit observed in angina patients treated by transmyocardial revascularization (TMR) with a laser, interest in mechanical TMR has been renewed. Although the injury induced by mechanical TMR is similar to laser TMR, the resultant impact on myocardial contractility is unknown. The purpose of this study was to determine whether mechanical TMR improves ventricular function as compared with laser TMR in chronically ischemic myocardium.

Methods. After establishing an area of chronic myocardial ischemia, 25 domestic pigs were randomized to treatment by: excimer laser (group I), a hot needle (50°C) (group II), a normothermic needle (group III), an ultrasonic needle (40 KHz) (group IV), or no treatment (group V). All devices create a transmural channel of the same diameter; 22 ± 1 transmural channels were created in each animal. Regional myocardial contractility was assessed by measuring ventricular wall thickening at rest and with dobutamine stress echocardiography. Six weeks after revascularization, the animals were restudied at rest and with stress. Postsacrifice and histologic analysis of angiogenesis and TMR effects was then assessed.

Results. Laser TMR provided significant recovery of ischemic myocardial function. This improvement in contractility after laser TMR was a 75% increase over the baseline function of the ischemic zone (p < 0.01). Mechanical TMR provided no significant improvement in function posttreatment. In fact, TMR achieved with an ultrasonic needle demonstrated a 40% worsening of the contractility versus the pretreatment baseline (p < 0.05). Histologic analysis demonstrated a significant increase in new blood vessels in the ischemic zone after laser TMR, which was not demonstrated for any of the other groups (p < 0.05). Additionally, evaluation of the mechanical TMR channels demonstrated significant scarring, which correlated with the functional results.

Conclusions. Using devices to create an injury analogous to the laser, mechanical TMR failed to improve the function of chronically ischemic myocardium. Only laser TMR significantly improved myocardial function.     

激光心肌打孔血运重建术的临床应用

作者对７例不能作冠状动脉搭桥和经皮冠状动脉球囊扩张、并且药物治疗无效的冠心病心绞痛患者使用国产７００瓦ＣＯ２激光器作激光心肌打孔血运重建术。７例患者心肌打孔数目１６２个,平均２４个。手术时间１５０±３０分。１例于术后第３天因呼吸衰竭死亡,其余６例术后随访２～１２个月。随访包括心绞痛级别、用药情况及心功能,并在术后３、６和１２个月检查超声心动图和心肌ＳＰＥＣＴ。结果显示：４例心绞痛消失,２例明显缓解。２例于打孔后１～６个月作平板运动试验,运动时间比术前延长,４例做超声心动图示静息状态下室壁动度均有增加,１例在术后１２个月左室射血分数由术前的４２％提高到５４％;２例做超声心动图－多巴酚丁胺检查示多巴酚丁胺对心室壁动度的作用及心肌对多巴酚丁胺的最大耐受量均比术前增强;心肌ＳＰＥＣＴ示与术前比心肌打孔区的血液灌注明显增加。作者认为：本方法作为冠心病治疗的一种新方法,可有效地缓解心绞痛,改善心肌血液灌注,提高心脏功能。     

Mid-term results of combined transmyocardial laser revascularization and coronary artery bypass

BACKGROUND: Transmyocardial laser revascularization is increasingly used to treat intractable angina in the absence of graftable vessels; however, its role in combination with coronary artery bypass grafting remains undefined. The aim of this pilot study was to investigate the outcome of the combination therapy at mid-term follow-up. METHODS: Patients (n = 20) who had elective coronary artery bypass with one or more nongraftable coronary arteries were prospectively randomized to have either coronary artery bypass grafting alone or combination coronary artery bypass grafting plus transmyocardial laser revascularization with a holmium:YAG (yttrium-aluminum-garnet) laser to nongraftable areas. All patients had an exercise tolerance test preoperatively and at 6, 18, and 36 months follow-up. Stress echocardiography was performed on 17 patients at 18 months postoperatively, and regional wall motion score index was calculated in lased and nonlased nonrevascularizable myocardium of the left ventricle at rest and with dobutamine stress. RESULTS: Both groups of patients were similar in preoperative demographics and operative data. There was no perioperative death. There was no difference between the two groups in angina scoring at 6, 18, and 36 months follow-up. Exercise tolerance improved by a mean of 46.8 +/- 20.0 seconds in the coronary artery bypass grafting group versus 199.2 +/- 66.5 seconds per patient in the coronary artery bypass grafting plus transmyocardial laser revascularization group (p = 1.8 x10(-6)) at 6 months; this benefit was maintained at 18 months (157 +/- 46.3 versus 61 +/- 39.2 seconds; p = 4 x10(-4)) but was lost at 36 months (57.2. +/- 42.1 versus 68.1 +/- 46.7 seconds; p = 0.70). The mean values for wall motion score index in the lased and nonlased regions at each stage of dobutamine stress at 18 months after surgery were not statistically significant. CONCLUSIONS: The combination of coronary artery bypass and transmyocardial laser revascularization improved exercise tolerance in patients in whom complete revascularization could not be achieved by bypass grafting alone in the short term, but this benefit was lost by 36 months postoperatively. The transient improvement in exercise tolerance cannot be explained by changes in contractility in the lased areas.     

Surgical ventricular restoration for ischemic cardiomyopathy; to further improve surgical outcomes

One of the problems of the surgical treatment for ischemic heart failure (STICH) trial was that they did not clearly show how they assessed preoperative myocardial viability. We have been stressing on the importance of accurate preoperative evaluation of myocardial viability to determine the indication of surgical ventricular restoration (SVR), and the location of the exclusion area, if indicated. To this end, we have been using late enhancement of magnetic resonance imaging (MRI), and the surgical strategy for patients with left ventricular ejection fraction (LVEF) less than 35% was constructed based on the findings of MRI. When the ventricle had the extent of hyperenhancement of less than 50% of its wall thickness in any region, complete revascularization with coronary artery bypass grafting (CABG) was performed without SVR. When the ventricle had extensive area of hyperenhancement of 50% or more of its wall thickness, the area was surgically excluded. The early and mid-term surgical outcomes were satisfactory in both the CABG only group and the CABG + SVR group. However, the patients who had residual myocardium with low viability were likely to show higher incidences of cardiac death and readmission for heart failure after SVR in the mid-term. Regeneration therapy of myocardium need to be developed to improve myocardial contractility of residual myocardium after SVR to obtain further better long-term surgical outcomes.     

Should coronary artery bypass be delayed following successful direct coronary artery streptokinase thrombolysis during evolving myocardial infarction?

The effect of deferring immediate coronary artery bypass was evaluated in two groups of similar patients having successful direct coronary artery thrombolysis with streptokinase in the treatment of evolving myocardial infarction. Within 6 hours of onset of myocardial infarction, 140 patients underwent immediate cardiac catheterization and infusion of intracoronary streptokinase up to 500,000 units. Of those patients having restoration of orthograde coronary blood flow coupled with immediate evidence of myocardial salvage, 31 patients (group I) had immediate coronary artery bypass and 34 patients (group II) had coronary artery bypass deferred. Group I had no hemorrhagic, hemodynamic, or new cardiac complications. There were no deaths, reinfarction, recurrence of angina, or loss of salvaged myocardium at restudy. In group II, 11 of 34 patients had early reinfarction (p less than 0.01 vs. group I), 16 of 34 patients had recurrent angina (p less than 0.01 vs. group I) and two deaths occurred from cardiac causes. Subsequent coronary bypass was needed in 16 patients. All restudied reinfarction patients lost restored myocardium. We concluded that immediate coronary artery bypass is safe after acute myocardial infarction and coronary artery thrombolysis with streptokinase, delay of coronary artery bypass leads to an unacceptable incidence of reinfarction and recurrent severe angina, and early coronary artery bypass is needed to ensure success of thrombolysis.     

Efficacy of crystalloid cardioplegic solutions in patients undergoing myocardial revascularization. Effect of infusion route and regional wall motion on preservation of adenine nucleotide stores

The effect of varying the mode of cardioplegic delivery and the presence of regional wall motion abnormalities on myocardial protection by crystalloid cardioplegic solutions was assessed in 68 patients undergoing coronary artery bypass grafting. Serial transmural biopsy specimens from the left ventricular apex were assayed for adenosine triphosphate. All patients had more than 75% stenosis of the left anterior descending coronary artery. They were prospectively randomized into Groups I and II to receive (I) all cardioplegic solution infused via the aortic root or (II) reinfusions of cardioplegic solution given both centrally and through the completed distal left anterior descending anastomosis. Patients were also stratified as to the presence of normal (N) or impaired (Ab) apicoanterior regional wall motion. Inadequate delivery of cardioplegia during ischemia in Group I was manifested by a 41% (p less than 0.01) depletion of adenosine triphosphate stores in abnormally contracting myocardium distal to the left anterior descending stenosis that was not repleted after restoration of coronary flow and a 27% (p less than 0.05) decline in ATP stores during reperfusion in myocardium with normal preoperative wall motion. In contrast, nucleotide stores were preserved at preischemic levels throughout ischemia and reperfusion in Group II regardless of preoperative wall motion. Preservation of ATP did not correlate with duration of ischemia, highest recorded septal temperature, or volume of cardioplegic solution infused. Two patients in each group had a new perioperative infarction. However, 38% of patients in Group IAb required transient inotropic support versus 5% in Group IIAb (p less than 0.05). These data emphasize that reinfusion of cardioplegic solutions distal to coronary obstructions is mandatory for optimal myocardial protection during coronary revascularization.     

Results after transplantation using donor hearts with preexisting coronary artery disease

OBJECTIVE: Cardiac allografts with coronary artery disease may permit a selective expansion of the donor pool. Twenty-two recipients who received donor hearts with mild to moderate coronary artery disease on angiography were reviewed. All donor organs had preserved left ventricle function on echocardiogram. METHODS: The procedure was explained to the patients in detail. All survivors have at least 1 year of follow-up. If the coronary arteries of the donor heart were significantly occluded, then the implanting surgeon performed coronary revascularization. Donors were allocated to patients facing imminent death (group I, n = 4) or to those who would otherwise not have been transplanted (group II, n = 18). Median recipient age was 57 years old for group I and 68 years old for group II. Median follow-up was 25 months for group I and 44 for group II. RESULTS: Outcome was evaluated using survival and freedom from graft coronary disease as end points. In group I, 3 of the 4 hearts required revascularization. In group II, 10 of the 18 required revascularization. The majority of the revascularizations were recipient saphenous vein grafts (84.6%) to the donor left anterior descending artery (50%). The 1-month and 2-year actual survivals for group I are 75% and 50% and 87.5% and 81.3 for group II. One patient in group I who was in extremis and 3 in group II died at less than 90 days. Group II early deaths had donor risk factor combinations of coronary artery disease, left ventricular hypertrophy, and long distance. Freedom from new graft coronary artery disease was 100% at 2 years in group I and 87.5% in group II. CONCLUSIONS: Selective use of donor hearts with coronary artery disease is acceptable. Early deaths are related to recipient factors as well as associated donor risk factors. Donor hearts with mild or moderate coronary artery disease and preserved function on echocardiogram can be used but may require revascularization with recipient conduit and/or percutaneous transluminal coronary artery angioplasty. Coronary disease in donor hearts requires grading and does not categorically preclude use, particularly in risk-matched recipients.     

The long-term results of the endovascular treatment of the ischemic heart disease

The long-term follow-up treatment results were analyzed for 171 patients operated on the reason of multiple coronary vessels atherosclerosis. The average follow-up time was 14.85 ± 2.52 months. The complete myocardium revascularization was achieved in 63 patients; functionally adequate myocardial function was registered in 86 patients; 22 patients demonstrated noncomplete revascularization rate. Results of complete and functionally adequate revascularization were not significantly different by the myocardial infarction, repeated revascularizative manipulations and main cardio-vessel complications rates. Patients of the third group demonstrated the statistically higher rates of myocardial infarction (p=0.016) and necessity of the coronal shunting (p=0.033).     

A clinical study of the myocardial protective effect of allopurinol

This study was proposed to study the myocardial protective effect of allopurinol clinically. This study involved 65 patients undergone coronary artery bypass operations or cardiac valve replacements or plasties. Patients were divided into two groups: group I, 30 patients received 2,400 mg of allopurinol preoperatively; group II, 35 patients undergoing no treatment of allopurinol. Postoperative values of GOT, CK-MB and LDH1 + LDH2 in group I were significantly lower than that of group II. These results suggest that allopurinol has advantageous effect on myocardial protection.     

Intramyocardial and intracoronary basic fibroblast growth factor in porcine hibernating myocardium: a comparative study

OBJECTIVE: Therapeutic angiogenesis is an alternative method of revascularization for end-stage coronary artery disease. We determined the effects of intramyocardial and intracoronary basic fibroblast growth factor 2 on myocardial blood flow and function in a porcine model of hibernating myocardium. METHODS: Twenty-four mini-swine with 90% left circumflex artery stenosis and documented hibernating myocardium by positron emission tomography and dobutamine stress echocardiography were randomized to intramyocardial basic fibroblast growth factor 2 at 0.6 microg/kg (mid-dose, n = 6, 30 injections/animal), 6 microg/kg (high-dose, n = 6, 30 injections/animal), or intramyocardial vehicle control (n = 6). The intracoronary group received 6 microg/kg basic fibroblast growth factor 2 (n = 6) into the right and left circumflex artery coronary arteries. Positron emission tomography and dobutamine stress echocardiography were repeated at 1 and 3 months. RESULTS: In the vehicle group, normalized left circumflex artery myocardial blood flow was 0.74 +/- 0.04 at 1 month and 0.75 +/- 0.07 at 3 months compared with 0.68 +/- 0.03 at baseline. In the intracoronary group, myocardial blood flow was 0.71 +/- 0.03 at 1 month and 0.72 +/- 0.04 at 3 months compared with 0.67 +/- 0.04 at baseline. In the mid group, myocardial blood flow was 0.73 +/- 0.06 at 1 month and 0.85 +/- 0.05 at 3 months (P <.001) compared with 0.67 +/- 0.04 at baseline. In the high group, myocardial blood flow was 0.81 +/- 0.06 at 1 month and 0.83 +/-.04 at 3 months (P =.03) compared with 0.71 +/- 0.02 at baseline. No significant improvements in ischemia were demonstrated in any of the groups by dobutamine stress echocardiography at 1 or 3 months. CONCLUSIONS: In porcine hibernating myocardium, intramyocardial basic fibroblast growth factor 2 significantly improved regional myocardial blood flow 3 months after treatment. There was no significant change in function in any of the 4 groups. These data suggest that intramyocardial dosing of basic fibroblast growth factor 2 (0.6 microg/kg) may be an optimal dose for improving perfusion in the treatment of end-stage coronary artery disease.     

Beating versus arrested heart coronary revascularization: evaluation by cardiac troponin I release

Background

This prospective randomized study aimed to compare beating and arrested heart revascularization in patients undergoing first elective coronary artery bypass graft, with cardiac troponin I release used to evaluate myocardial injury.

Methods

Seventy patients were randomly assigned to a beating or arrested heart revascularization group. Cardiac troponin I concentrations were measured in serial venous blood samples drawn preoperatively in both groups: after aortic unclamping at 6, 9, 12, and 24 hours in the arrested heart group and after the last anastomosis at 6, 9, 12, and 24 hours in the beating heart group. Analysis of covariance with repeated measures was performed to test the effect of group and time on cardiac troponin I concentration.

Results

The total amount of cardiac troponin I released was higher in the arrested heart revascularization group than in the beating heart revascularization group (8.25 ± 6.16 vs 3.18 ± 4.75 μg, p < 0.0001). Cardiac troponin I concentrations were significantly higher in the arrested heart group at hours 6, 9, 12, and 24 than in the beating heart group (p < 0.0001).

Conclusions

The lower release of cardiac troponin I in the beating heart revascularization group indicates that conventional coronary artery bypass graft with cardioplegic arrest causes more damage to the heart than off-pump myocardial revascularization.     

Beating versus arrested heart revascularization: evaluation of myocardial function in a prospective randomized study.

OBJECTIVE: Conventional coronary artery bypass grafting (CABG) is both safe and effective. Nevertheless, the use of cardiopulmonary bypass (CPB) and cardioplegic arrest are associated with several adverse effects. Over the last 2 years there has been a revival of interest in performing CABG on the beating heart. In this prospective randomized study we evaluated the efficacy and safety of on and off pump coronary revascularization on myocardial function. METHODS: Eighty patients (65 males, mean age 61+/-9.7 years) undergoing first time CABG were prospectively randomized to: (i) conventional revascularization with CPB at normothermia and cardioplegic arrest with intermittent warm blood cardioplegia (on pump) or (ii) beating heart revascularization (off pump). Troponin I (Tn I) release was serially measured as a specific marker of myocardial damage. Haemodynamic measurements as well as inotropic requirement, incidence of arrhythmia and postoperative myocardial infarction were also recorded. RESULTS: There were no significant differences between the two groups in terms of age, sex, extent of disease, left ventricular function and number of grafts. There were no deaths or intraoperative myocardial infarctions in either group. Tn I release was constantly lower in the off pump group and this was significant at 1, 4, 12 and 24 h postoperatively. Furthermore, in this group there was a significantly reduced incidence of arrhythmias. Inotropic requirements were less in the off pump group but this did not reach statistical significance. CONCLUSION: These results suggest that off pump coronary revascularization is a safe and effective strategy for myocardial revascularization. Myocardial injury as assessed by Tn I release is also reduced when compared with conventional coronary revascularization with CPB and cardioplegic arrest.     

Myocardial perfusion scintigraphy as a screening method for significant coronary artery stenosis in cardiac transplant recipients.

BACKGROUND: Several studies have explored the feasibility of using myocardial perfusion imaging to detect allograft vasculopathy after heart transplantation. We undertook the present prospective consecutive study to comparatively evaluate the role of serial myocardial perfusion single-photon emission computed tomography (SPECT) scanning and coronary arteriography (CAG) in detecting coronary artery stenosis suitable for coronary angioplasty in heart transplant recipients. METHODS: Within a 2-week interval during a follow-up period of 5.6 (95% confidence limits 2.1 to 12) years, 255 serial CAGs and myocardial perfusion scintigraphies were performed in 67 patients. Arteriography and scintigraphy were performed once yearly after heart transplantation. We retrospectively analyzed the data. RESULTS: Myocardial scintigraphy showed pathologic reversible defects in 9 out of 67 patients. Four of these patients had significant (>50% and also >70%) focal segmental stenosis in the middle and proximal parts of the coronary arteries (Type A lesions), 1 had diffuse and circumferential narrowing in the distal parts (Type B lesions), whereas CAG showed no lesions in the remaining 4 patients. The patients with significant Type A lesions were revascularized with percutaneous coronary angioplasty. Coronary arteriography showed that 1 patient had extensive Type A and Type B lesions, whereas myocardial perfusion scans detected no. The predictive value of a negative (normal) SPECT was 98% (95% confidence limits 94% to 100%) for the detection of lesions suited for revascularization. CONCLUSIONS: Annual myocardial SPECT seems well suited to screen for significant coronary artery stenosis. A SPECT study without reversible defects virtually excludes lesions suitable for coronary artery revascularization.     

Coronary revascularization in end-stage coronary heart disease in relation to assessment of myocardial vitality]

From 4/1986-12/1990, 177 pts. with endstage coronary artery disease (CAD) and left ventricular ejection fraction 10-30% received coronary artery bypass grafting (CABG). Preoperatively myocardial infarction rate was 1.5 (mean). Presupposition for CABGs was myocardial ischaemia at present demonstrated in myocardial viability test. 66.1% of the pts. had signs of ischaemia at e.c.g. after work. Additionally 97.6% of the pts. had myocardial ischaemia defined as redistribution in myocardial scintigraphy. Angina pectoris was present in 93.8% of the pts. preoperatively. 1-5 (mean 2.9) CABG per pt. were performed. 35 pts. received an internal mammaria bypass to the left coronary artery also. Operative mortality was 11.3% (1986-1990) and in 1990 alone 7.3%. Actuarial survival rate was calculated after one year to 87.4% after two years to 86.1% and after three years to 84.8%. Postoperatively all pts. were free from angina pectoris. 5 months after the operation e.c.g. after work was performed. The physical stress bearing area was increased to 82.7 Watt (mean) compared to 51.7 Watt (mean) preoperatively (p less than 0.001 s.). In conclusion pts. with endstage CAD and left ventricular ejection fraction 10-30% appeared to be good candidates for CABG with good prognosis and significant symptomatic improvement when signs of myocardial ischaemia are present preoperatively.     

Quantitative assessment of myocardial viability following coronary artery bypass grafting using exercise thallium-201 myocardial single photon emission computed tomography and left ventricular regional wall motion

Using exercise thallium-201 myocardial single photon emission computed tomography (SPECT) and % radial shortening (%RS), 58 patients were evaluated before and after coronary artery bypass grafting (CABG) to quantitatively assess myocardial viability and the effect of CABG. The patient was classified, according to redistribution pattern, as group I with only complete redistribution (20 cases) and group II with including incomplete redistribution (22 cases) and group III with no redistribution (16 cases). 1. Group I was expected complete improvement of ischemic myocardium after CABG but regional left ventricular wall motion was unchanged (sigma i%RS: 142.5 +/- 54.7----138.4 +/- 39.6, sigma a%RS: 201.2 +/- 51.1----238.2 +/- 68.2). 2. Group II was expected to diminish ischemic size after CABG and left ventricular regional wall motion was significantly improved (sigma i%RS: 68.8 +/- 25.9----154.9 +/- 42.6 p less than 0.01, sigma a%RS: 108.4 +/- 62.3----178.9 +/- 77.6, p less than 0.05). 3. Group III was no significant change of ischemic size and left ventricular wall motion after CABG (sigma i%RS: 67.8 +/- 24.1----83.9 +/- 19.2, sigma a%RS: 86.0 +/- 29.0----94.0 +/- 33.9). The present study suggests that quantitative assessment of myocardial viability using exercise thallium-201 myocardial SPECT and %radial shortening was useful method to determine the indication and to assess the effect of CABG.     

Coronary artery bypass grafting in patients with poor left ventricular function using retrograde continuous cold blood cardioplegia]

Patients with poor left ventricular function or those requiring urgent surgery may have more extensive ischemic myocardial injury if myocardial preservation is incomplete. We have performed coronary artery bypass grafting (CABG) aimed at complete revascularization in such cases using RC-CBCP, which is considered more effective on myocardial preservation during aortic cross-clamping in particular to protect ischemic area distal to severe coronary artery stenosis or obstruction. In the present study, in 25 patients with poor left ventricular function (left ventricular ejection fraction; LVEF less than or equal to 0.3) including 10 patients who required urgent surgery, the operative results were evaluated. All the distal and proximal anastomoses of grafts (average 2.5 grafts) were completed during one aortic cross-clamping using RC-CBCP, therefore graft flow was obtained immediately after release of the aortic clamping. Though this method required 142 minutes of a mean aortic cross-clamping time, myocardial protection was considered to be preferable judging from postoperative isoenzymatic evaluation and improved ventricular function. Fifteen patients with elective CABG were all alive and restored to NYHA class I to II. Among 10 patients requiring urgent CABG, 4 patients with acute myocardial infarction died but others were restored to NYHA class I to II. We conclude that it is important to aim at complete coronary revascularization in patients with poor left ventricular function and RC-CBCP achieves more effective myocardial protection during CABG in the patients.