Experimental and Clinical Studies on the Effect of Intra-Aortic Balloon Pumping for Cardiogenic Shock Following Acute Myocardial Infarction

The effect of intra-aortic balloon pumping (IABP) on cardiogenic shock following acute myocardial infarction was studied experimentally and clinically. Effects of IABP on hemodynamic and electro-cardiographic changes were studied with cardiogenic shock which was produced by multiple ligation of the coronary artery in dogs. Consequently, the hemodynamics as well as the ECG could be improved by diastolic augmentation and systolic unloading during IABP. But, these favorable effects of IABP were not seen in dogs whose infarcted area involved more than 50% of the free wall of the left ventricle. These facts were seen clinically in three autopsied cases. IABP was also attempted in dogs with complications such as ventricular septal defect (VSD) and mitral regurgitation (MR) following acute myocardial infarction, and significant improvement was obtained by IABP. No effects of IABP were seen in these series, however, when the value of the pulmonary-to-systemic flow ratio was over 4.5 in the VSD group and the mean left atrial pressure was more than 30 mmHg in the MR group. Clinically, IABP was employed in 16 patients with cardiogenic shock secondary to acute myocardial infarction. Six (37.5%) were weaned from IABP. It can be concluded that IABP is effective in improving hernodynamics as well as the ECG.     

Benefits of combined balloon pumping and percutaneous cardiopulmonary bypass.

Sixteen patients (2 women, 14 men) aged 29 to 72 years with continued cardiogenic shock during intraaortic balloon pumping (IABP) had additional treatment with percutaneous cardiopulmonary bypass (PBY). Cause of cardiogenic shock was myocardial infarction in 7 (3 survived), failed percutaneous transluminal coronary angioplasty requiring emergency coronary artery bypass grafting in 5, postoperative aortic valve replacement in 1, postoperative emergency coronary artery bypass grafting in 1, after cardiac transplantation in 1, and bridging to transplantation in 1. Mean blood pressure with PBY and IABP combined was 75 mm Hg versus 60 mm Hg with IABP off. Percutaneous cardiopulmonary bypass flows ranged from 0.8 to 2.1 L/min with a mean flow of 1.3 L/min. Time on IABP ranged from 24 hours to 1 week. Time on IABP to PBY ranged from 1 to 20 hours, and time on PBY ranged from 65 minutes to 20 hours. Ten of 16 (63%) were successfully weaned, and 3 died after weaning. Seven of 16 (44%) survive. Combined IABP with PBY appears to be a better therapy than either one individually. Staging the therapy as the balloon first in and last out appears to be a good methodology.     

心肌梗塞后室间隔穿孔的手术治疗

探讨急性心肌梗塞后室间隔穿孔的手术时机选择及影响手术疗效的因素。１６例急性心肌梗塞后室间隔穿孔病人接受了手术治疗。平均年龄５４．５岁。术前合并心源性休克５例，充血性心力衰竭伴肺水肿１例。１４例行冠状动脉造影，单支病变８例，多支病变６例，合并室壁瘤１３例。急症手术４例，择期手术１２例。行穿孔直接缝合２例，补片修补１３例，双侧补片修补１例；同期冠脉搭桥９例，室壁瘤切除或折叠１３例。术后应用主动脉内球囊反搏（ＩＡＢＰ）者８例。２例急症手术者早期死亡。结论：室间隔穿孔应先行内科治疗控制心源性休克，包括应用ＩＡＢＰ或左心室辅助等，使病人能坚持到穿孔４８小时后再积极手术。分流量小者应延至３～６周后手术。心源性休克是影响术后早期死亡率的主要因素     

A case of acute postinfarction mitral insufficiency and cardiogenic shock caused by total rupture of a papillary muscle

A 61-year-old male in cardiogenic shock was transferred to our hospital with an intra-aortic balloon pumping (IABP). He had had acute posterior myocardial infarction previous day. He had developed progressively increasing dyspnea and physical signs of severe congestive failure. On admission, his blood pressure was 60 mmHg even with IABP. He was anuric with a high blood urea nitrogen and serum creatinine level. An echocardiogram demonstrated a rupture of a posterior papillary muscle and massive mitral insufficiency. His deteriorating condition did not allow us to perform cardiac catheterization. He underwent an emergency operation. Total rupture of a posterior papillary muscle was confirmed. Mitral valve replacement with a SJM prosthetic valve was performed. A postoperative course was uneventful.     

Off-pump coronary artery bypass grafting for patients with cardiogenic shock due to acute myocardial infarction

Off-pump coronary artery bypass (OPCAB) is less invasive, so we have recently been expanding the indication. We performed OPCAB for 3 patients with cardiogenic shock due to acute myocardial infarction (AMI). PATIENTS: All patients were supported hemodynamically by intra-aortic balloon pumping (IABP) prior to surgery. RESULTS: We performed the revascularization of territories for the left anterior descending artery (LAD) and right coronary artery (RCA) in these high risk patients using OPCAB technique to improve the hemodynamic state. In all patients, IABP was removed within 48 hours after surgery and the postoperative course was uneventful. CONCLUSIONS: It seems that OPCAB is a useful and effective procedure for a selected patient even with cardiogenic shock due to AMI.     

Beating heart coronary artery bypass grafting for acute myocardial infarction

We consider that off-pump coronary artery bypass grafting (CABG) [OPCAB], which results in local myocardial ischemia, is more effective for patients with acute myocardial infarction (AMI) than conventional CABG under cardiac arrest with global myocardial ischemia. Twenty-one patients (15 males, 6 females) received OPCAB for AMI, among whom surgery was performed following percutaneous coronary intervention (PCI) failure in 4 and PCI was performed prior to OPCAB in 2, while PCI was not performed in the remaining 15. Preoperatively, 16 patients had intraaortic balloon pumping (IABP), and 4 had IABP and percutaneous cardiopulmonary support (PCPS). The mean interval from onset to surgery was 11.7 (range 3 to 40) hours. In 20 cases, a complete revascularization was performed. The mean number of bypasses was 2.3 and OPCAB was carried out in 14 patients. In 2 cases, OPCAB was converted to on-pump beating CABG for complete revascularization. Fourteen patients (67%), each maintained with preoperative left ventricular ejection fraction (EF), were discharged with an elective bypass. Four patients died after on-pump beating CABG, in whom EF was lower than 10%. In addition, 3 died of low cardiac output syndrome (LOS) under PCPS and 1 of ventricular fibrillation. Based on our results, we considered that complete revascularization using OPCAB was effective for cases of AMI with PCI difficulty. However, in shock cases requiring PCPS, cardiac function was not improved even after revascularization. Therefore, it is necessary to study new procedures for shock cases during the period from onset to surgery.     

Effect of RVAD for right heart failure involved with right ventricular infarction--especially studies of myocardial regional blood flow and epicardial mapping electrocardiography

In recent years, the number of cases in which a ventricular assist device is required for serious heart failure not responding to conventional mechanical circulatory assistance, has been increasing. It should be pointed out, however, that the majority of the new device is to assist the left ventricle, and that the effect of right ventricular assist device (RVAD) has not been fully clarified yet. The effect of RVAD and intra-aortic balloon pumping (IABP) on right ventricular failure due to right ventricular infarction was studied in swine. Right ventricular infarction was made by means of right coronary artery ligation. After preparation of right ventricular infarction, both mean aortic pressure and cardiac output were reduced and elevated central venous pressure, increased right ventricular end-diastolic pressure, dilatation of right ventricular free wall, were noted and diagnosed as a cardiogenic shock due to acute right ventricular infarction. Right ventricular infarcted area was evaluated by epicardial mapping ECG and myocardial regional blood flow. It was found that in the cases using IABP, the effect of reducing the infarcted area due to diastolic augmentation was noted, but the effect on the right ventricular support was not satisfactory, while in the cases using RVAD, the right ventricular preload was reduced and the right ventricular stroke work was decreased, and the effect of reducing the infarcted area was observed. But hemodynamic effect of these method were not satisfactory, enough to assist recovery from cardiogenic shock.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evolving Indications for Preoperative Intraaortic Balloon Pump Assistance

Over a two-year period about 1,000 operations were performed with cardiopulmonary bypass. Intraaortic balloon pump assistance (IABP) was employed on 150 occasions, and a review of these has permitted clarification of the indications for its use.Sixty patients had IABP for cardiogenic shock either after infarction or after cardiotomy, and 37 (62%) survived. Preoperative IABP in 90 high-risk patients resulted in survival for 79 (88%). The indications for prophylactic IABP included: (1) relief of severe pain, which occurred in 42 patients with acute coronary insufficiency, (2) improvement in the coronary perfusion pressure, which was accomplished in 20 patients with significant left main coronary artery occlusion or its equivalent, and (3) protection of left ventricular function, which was carried out in 28 patients with an LV ejection fraction of less than 0.40. The significance of the preoperative endocardial viability ratio (EVR) in relation to prophylactic IABP was also assessed: an EVR below 0.70 appears to be an indication for preoperative IABP.     

Evaluation of preoperative intra-aortic balloon pump support in high risk coronary patients

Objective: The intra-aortic balloon pump (IABP) is an established additional support to pharmacological treatment of the failing heart after myocardial infarction, unstable angina and cardiac surgery. The effect of preoperative IABP in high risk patients was evaluated. Methods: Between June 1994 and March 1996 all high risk patients for CABG (two or more of these criteria: Left ventricular ejection fraction (LVEF) ≤40%, left main stem stenosis ≥70%, REDO-CABG, unstable angina) were randomized into either of 3 groups: (1) IABP 1 day prior to surgery, (2) IABP 1–2 h prior to CPB and (3) no preoperative IABP, controls. Exclusion criteria: cardiogenic shock preoperatively. Fifty-two patients have entered the study—group 1 (13 patients), group 2 (19 patients) and group 3 (20 patients). Preoperative patient characteristics and operative data revealed no group differences. There were 56% REDO's, unstable angina 59%, LVEF≤40%, 87% (34.0±11.6%) and left main stem stenosis in 35%. Results: The CPB-time was shorter in groups 1 and 2 88.7±20.3 min than in group 3 105.5±26.8 min, P<0.001, while ischemia time did not differ. Hospital mortality was higher in group 3, 25% vs. 6% (groups 1 and 2). Postoperative low cardiac output was seen in 12 patients (60%) in group 3 vs. 6 patients (19%) in groups 1 and 2, P<0.05. Cardiac index increased significantly prior to CPB in groups 1 and 2. After CPB cardiac index was significantly higher in groups 1 and 2 compared to Group 3 and continued to increase. The IABP was removed after 3.1±1.0 days in group 3 vs. 1.3±0.6 days in groups 1 and 2, P<0.001. In group 3, 11 patients required IABP postoperatively compared to only 4 patients in groups 1 and 2. ICU stay was shorter in groups 1 and 2—2.3±0.9 days vs. 3.5±1.1 days for group 3, P=0.004. All patients received dopamin postoperatively, however in a lower dose in groups 1 and 2, 4.5 vs. 13.5 μg/kg/min. Dobutamine was added in 23% of the patients (group 1), 32% (group 2) and 95% (group 3). Adrenalin/amrinonum was required in 40% of the patients in group 3, 5% in group 2 and none in group 1. Group 1 patients had a better improvement of cardiac performance than group 2, while other parameters did not differ. Three months follow up of hospital survivors showed no group differences. Conclusions: The use of preoperative IABP in high risk patients lowers hospital mortality and shortens the stay in ICU, due to improved cardiac performance, compared to a controls. The procedure was cost-beneficial. One day preoperative IABP treatment improves cardiac performance more than 1–2 h preoperative IABP treatment, but does not significantly affect the outcome in terms of hospital mortality or postoperative morbidity.     

Intra‐Aortic Balloon Pump Support in the Isolated Beating Porcine Heart in Nonischemic and Ischemic Pump Failure

The blood pressure changes induced by the intra‐aortic balloon pump (IABP) are expected to create clinical improvement in terms of coronary perfusion and myocardial oxygen consumption. However, the measured effects reported in literature are inconsistent. The aim of this study was to investigate the influence of ischemia on IABP efficacy in healthy hearts and in shock. Twelve slaughterhouse porcine hearts (hearts 1–12) were connected to an external circulatory system, while physiologic cardiac performance was restored. Different clinical scenarios, ranging from healthy to cardiogenic shock, were simulated by step‐wise administration of negative inotropic drugs. In hearts 7–12, severe global myocardial ischemia superimposed upon the decreased contractile states was created. IABP support was applied in all hearts under all conditions. Without ischemia, the IABP induced a mild increase in coronary blood flow and cardiac output. These effects were strongly augmented in the presence of persisting ischemia, where coronary blood flow increased by 49 ± 24% (P < 0.01) and cardiac output by 17 ± 6% (P < 0.01) in case of severe pump failure. As expected, myocardial oxygen consumption increased in case of ischemia (21 ± 17%; P < 0.01), while it slightly decreased without (?3 ± 6%; P < 0.01). In case of progressive pump failure due to persistent myocardial ischemia, the IABP increased hyperemic coronary blood flow and cardiac output significantly, and reversed the progressive hemodynamic deterioration within minutes. This suggests that IABP therapy in acute myocardial infarction is most effective in patients with viable myocardium, suffering from persistent myocardial ischemia, despite adequate epicardial reperfusion.     

Treatment of post-myocardial infarction angina by intra-aortic ballon pumping and emergency revascularization.

Twenty-one patients with postinfarction angina (2 to 15 days after acute myocardial infarction) unresponsive to medical therapy were treated by intra-aortic balloon pumping (IABP). Anginal pain and electrocardiographic (ECG) ST-segment changes were prevented in all patients. Coronary angiograms were obtained during IABP without complication and confirmed severe coronary artery disease. Of the four nonoperated patients, three had reinfarction and two died of cardiogenic shock. Seventeen patients underwent aorta-coronary bypass grafting, associated with aneurysmectomy in two patients and closure of a ventricular septal defect in one. Sixteen patients survived the operation. All survivors are in clinically improved condition and 14 are pain free from 9 to 28 months postoperatively, but three have mild heart failure.     

Operation for acute postinfarction mitral insufficiency and cardiogenic shock

Since 1973, 11 patients have had emergency valve replacement for severe mitral insufficiency and cardiogenic shock within 1 month (mean 10.0 days) of acute myocardial infarction. Mean age was 60 years (range 44 to 71 years). Nine infarcts affected the inferior wall, one patient had a prior myocardial infarction, and only two patients had a history of cardiac symptoms. Ten patients had pulmonary edema, five were oliguric (less than 0.5 ml/kg/hr for 12 hours), four required endotracheal intubation, nine required preoperative intra-aortic balloon support, and three had had a cardiac arrest. Preoperative cardiac index averaged 1.7 L/m2/min even with pharmacologic and circulatory support. Eight patients had cardiac catheterization and nine had echocardiograms. Left ventricular ejection fraction varied from 23% to 83% (mean 51%) and was not prognostic. Five patients had papillary muscle rupture and six patients had papillary muscle dysfunction. The mitral valve was replaced with a mechanical prosthesis in all patients. Five had simultaneous coronary artery bypass grafts. Three of five patients with papillary muscle rupture and two of six with papillary muscle dysfunction survived hospitalization. Two patients could not be weaned from cardiopulmonary bypass, two patients died within 24 hours of low cardiac output, and two patients died 3 weeks postoperatively of acute tubular necrosis and sepsis following prolonged preoperative cardiogenic shock. The interval from onset of shock to operative therapy averaged 1.7 days for survivors versus 9.3 days for nonsurvivors. Although the amount of viable left ventricular mass cannot be measured preoperatively, we recommend early operation, before other organ systems fail, for patients having severe mitral insufficiency and cardiogenic shock within 30 days of acute myocardial infarction.     

Intra-aortic balloon counterpulsation in the treatment of infarction-related cardiogenic shock--review of the current evidence

The European ST-elevated myocardial infarction (STEMI) guideline suggested the intra-aortic balloon pump (IABP) with a recommendation level I and a level of evidence C as an effective measure in combination with balloon angioplasty in patients with cardiogenic shock (CS), stent implantation, and inotropic and vasopressor support. Similarly, upon mechanical complication due to myocardial infarction (MI), the guideline suggests that in patients with a ventricular septal defect or in most patients with acute mitral regurgitation, preoperative IABP implantation is indicated for circulatory support. The American College of Cardiology/American Heart Association STEMI guideline recommends the use of the IABP with a recommendation level I and a level of evidence B if CS does not respond rapidly to pharmacological treatment. The guideline notes that the IABP is a stabilizing measure for angiography and early revascularization. Even in MI complications, the use of preoperative IABP is recommended before surgery. Within this overview, we summarize the current evidence on IABP use in patients with CS complicated by MI. From our Cochrane data analysis, we conclude that in CS due to acute MI (AMI) treated with adjuvant systemic fibrinolysis, the IABP should be implanted. In patients with CS following AMI, treated with primary percutaneous coronary intervention (PCI), the IABP can be implanted, although data are not distinctive (i.e., indicating positive and negative effects). In the future, randomized controlled trials are needed to determine the use of IABP in CS patients treated with PCI. When patients with CS are transferred to a PCI center with or without thrombolysis, patients should receive mechanical support with an IABP. To treat mechanical MI complications-in particular ventricular septal defect-patients should be treated with an IABP to stabilize their hemodynamic situation prior to cardiac surgery. Similar recommendations are given in the German Austrian guidelines on treatment of infarction-related CS patients (http://www.awmf.org/leitlinien/detail/ll/019-013.html).     

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.     

The effect and role of the intraaortic balloon pumping in off-pump coronary artery bypass

Eighty consecutive patients who underwent off-pump coronary artery bypass (OPCAB) were studied. They were divided into group I (n = 10) which received preoperative intraaortic balloon pumping (IABP), and group II (n = 70) which did not receive IABP. The indications for preoperative IABP were severe left main coronary artery disease in 7 patients, severe 3 vessel disease in 3 patients, unstable angina in 5 patients, acute myocardial infarction in 3 patients. There was no operative mortality in both groups. The average number of distal anastomosis 2.7/patients in group I and 3.3/patients in group II. There was no differences in ventilator support time, length of stay in the intensive care unit and morbidity between 2 groups. The average postoperative IABP support time was 5.4 hours. There was no IABP-related complication in group I. IABP was very effective to perform OPCAB surgery safety. Preoperative IABP may be effective modality to support OPCAB surgery not only in emergent case but also in elective case.     

Intraaortic balloon counterpulsation and cardiac surgery

Sixteen months' experience with intraaortic balloon pumping in a cardiac surgical unit is reported. Eight patients presented in cardiogenic shock and required immediate pumping prior to cardiac catheterization and operation. Sixteen patients undergoing elective cardiac procedures had pumping in the immediate postoperative period because of myocardial depression. Twenty of these 24 patients were able to be restored to cardiovascular stability. Mortality and morbidity in these patients are discussed as well as complications of intraaortic balloon counterpulsation. Our current methods of balloon insertion and deployment are presented.     

New aspects on the role of blood pressure and arterial stiffness in mechanical assistance by intra-aortic balloon pump: in-vitro data and their application in clinical practice

Despite the well-known beneficial effects of the intra-aortic balloon pump (IABP) generally, there are still some clinical conditions accompanied by IABP ineffectiveness. The aim of this study was the investigation of the independent effects of arterial stiffness and blood pressure on acute IABP effectiveness. For this purpose, a mock circulatory system and 20 patients with cardiogenic shock due to acute myocardial infarction, were employed. It was shown that IABP acute efficiency was determined primarily by arterial compliance (AC) rather than blood pressure alone. IABP induced low hemodynamic effects in patients with systolic blood pressure > 80 mm Hg but with increased AC, whereas IABP resulted in greater hemodynamic effectiveness in cases with systolic pressure < 70 mm Hg but lower AC. The present study provides evidence concerning the hemodynamic conditions, which might lead to optimization of IABP or to the prediction of its acute hemodynamic performance, based on both measurements of AC and blood pressure.     

Emergency coronary artery bypass grafting for acute coronary syndrome with preoperative intraaortic balloon pumping; comparative surgical outcome and long-term results

With recent technical improvements in catheter interventional therapy, percutaneous coronary intervention (PCI) has now become the treatment of first choice for acute coronary syndrome (ACS). The objective of the present study was to evaluate critically the timing of coronary artery bypass grafting (CABG) for severe ACS with preoperative intraaortic balloon pumping (IABP). Since 1994, a total of 70 patients have gone emergency or urgent CABG for ACS. Of 70 patients, 50 patients required preoperative IABP. There were 22 patients (17 men, 5 women) with acute myocardial infarction (AMI), with a mean age of 67.7 years, and 28 patients (19 men, 9 women) with unstable angina pectoris (UAP), with a mean age of 69.2 years. There was a significant difference, between AMI and UAP, in the prevalence of emergency operation (95.5% vs 25.0%), in preoperative cardiogenic shock (81.8% vs 17.9%), in the level of preoperative CPK-MB (196.7 IU/l vs 2.0 IU/l) and in preoperative ejection fraction (41.8% vs 47.3%). Two patients in AMI required percutaneous cardiopulmonary support (PCPS). Thirteen patients in AMI and 22 patients in UAP presented left main trunk (LMT) disease. Of the 13 LMT patients in AMI, 4 patients were AMI due to acute occlusion in the LMT. The AMI patients received 2.45 distal anastomoses on average, while the UAP patients 3.14 distal anastomoses (p = 0.019). Excluding the mean number of distal anastomoses, there was no difference in the intraoperative technical factors, such as aortic cross clamping duration, cardiopulmonary bypass duration, rate of complete revascularization, between AMI and UAP. There were postoperative significant differences in low cardiac output syndrome (LOS) [45.6% in AMI vs 3.6% in UAP] and in prolongation of mechanical ventilation (59.1% in AMI vs 14.3% in UAP). The hospital mortality was 9.1% (2/22) in AMI, and 3.6% (1/28) in UAP, with no significant difference. Of these 3 patients, 1 patient died from perioperative cerebrovascular accident (CVA), another from LOS, and the other from postoperative mesenteric ischemia, with an overall mortality of 6.0% (3/50). The overall patency rate of the grafts was 100% in AMI and 96.6% in UAP. The 5-year-survival rate excluding in-hospital death was 72.5% in AMI, and 89.6% in UAP. The 5-year-cardiac event-free rate was 77% in AMI and 89.4% in UAP. The overall survival rate, and cardiac event-free rate, at 5 years was 80.8%, and 83.8%, respectively. In conclusion, for ACS cases, especially UAP cases of LMT, in which symptoms, findings of ischemia and hemodynamics are stabilized by medical intervention including IABP; emergency surgery could be avoided immediately after coronary angiography. Recovery in the ischemic myocardium is intended by IABP, and urgent surgery should be performed after sufficient and precise preoperative examinations. An improvement not only in the perioperative but also long-term results can be expected by performing complete revascularizations.     

The effects of intraaortic balloon counterpulsation on myocardial infarct size.

The left anterior descending coronary artery was ligated in 6 baboons. Subsequently, 3 animals were supported with long-term (24-hour) intraaortic balloon pumping (IABP), and 3 were on coronary occlusion alone. Animals were studied hemodynamically and with unipolar electrocardiographic mapping acutely and then were studied after a week and killed. A histological measurement of infarct size was made. The use of IABP had no influence on the area of ischemia determined by unipolar mapping or on infarct size measured quantitatively at a week. Similarly, there were no acute hemodynamic differences between the two groups. The only significant difference noted was a reduction in systolic pressure in IABP animals during balloon pumping and a significantly higher left ventricular systolic pressure a week following infarction in animals treated with IABP. The data indicate no significant effect of IABP on altering infarct size in animals with acute coronary ligation in the absence of cardiogenic shock.     

Cardiovascular parameters after acute myocardial infarction and streptokinase administration in patients receiving coronary artery bypass grafts

In 16 patients requiring coronary artery bypass grafting (10 control and 6 streptokinase patients), we compared the preoperative, operative, and postoperative cardiovascular parameters. Streptokinase patients had an acute myocardial infarction and attempted reperfusion with streptokinase before coronary artery bypass grafting. One patient failed to recannalize with streptokinase and one patient had reocclusion after withdrawal of heparin necessitating coronary artery bypass grafting. Examination of hemodynamic parameters revealed a lower preoperative mean blood pressure and an elevated pulmonary artery wedge pressure in streptokinase patients. The elevated pulmonary artery wedge pressure persisted through the postoperative period of observation. These results indicate that only minor differences exist between control and streptokinase patients. Emergency and elective coronary artery bypass grafting can be safely performed in patients treated with streptokinase for acute myocardial infarction without associated cardiogenic shock.