Unstable angina and evolving myocardial infarction following coronary bypass surgery: pathogenesis and treatment with interventional catheterization

Effective therapy for patients with unstable angina or evolving myocardial infarction following coronary bypass surgery requires accurate delineation of the pathoanatomy and prompt intervention. We therefore performed cardiac catheterization in 10 consecutive patients: four with acute myocardial infarction and six with refractory unstable angina (NYHA class IV). All patients with acute myocardial infarction were found to have completely thrombosed vein grafts supplying totally occluded native coronary arteries. In three patients with evolving myocardial infarction occurring within 4 weeks of coronary bypass surgery, graft thrombosis was caused by venous valves in two patients and a suboptimal anastomosis in a third. The fourth patient sustained a myocardial infarction 7 years after coronary bypass surgery with atherosclerotic plaque rupture causing vein graft thrombosis. Therapy with intragraft streptokinase resulted in complete clearing of thrombus, pain relief, and control of injury current in all four patients. Rest angina with concomitant ST and T wave changes occurred in six patients. In two patients symptoms occurred early (within 6 months), whereas angina developed 4 to 10 years after coronary bypass graft surgery in four patients. In the two patients with early recurrence of symptoms suboptimal anastomosis was found in one, while the other patient had a venous valve in the vein graft in conjunction with a stenosis in the native coronary artery. In three of four patients with late recurrence of angina, symptoms developed as a result of atherosclerotic stenosis in their vein grafts; in the fourth patient an occluded graft was found to supply a stenosed native coronary artery.(ABSTRACT TRUNCATED AT 250 WORDS)     

The internal mammary artery in myocardial revascularization

Internal mammary artery by-pass graft is a very usefull alternative to venous by-pass graft for myocardial revascularization. From February 1982 up to August 1984, 111 patients with coronarosclerosis have been operated on with left internal mammary artery. Right internal mammary artery has been also used in 2 cases. Left internal mammary artery has been used as a sequential graft 13 times. Vein grafts have been associated in more than 2/3 of the patients who had surgery with internal mammary artery and the mean of anastomoses per patient was 2.9. Five patients had a perioperative myocardial infarction and one an infarction shortly after the operation. Ten patients had immediate reoperation: 5 for postoperative bleeding, 2 for arterial graft anastomosis occlusion, 2 for sudden ST elevation and 1 for acute myocardial infarction. Only one patient died for acute myocardial infarction post-operatively, following coronary artery spasm. Eighty-six patients have been followed-up 3 to 31 months after surgery. Advantages and limits of this surgical technique are discussed.     

The spectrum of pathology associated with percutaneous transluminal coronary angioplasty during acute myocardial infarction

The purpose of this study was to determine at necropsy the morphologic consequences of percutaneous transluminal coronary angioplasty performed during acute myocardial infarction. The heart was examined in four patients who died between 6 hours and 4 days after coronary angioplasty. The patients had angioplasty of the left main coronary artery (one patient), left anterior descending coronary artery (two patients) and left circumflex coronary artery (one patient). Necropsy revealed residual stenosis, intimal hemorrhage and plaque disruption in all four patients. Also noted were distal embolization of plaque elements (two patients) and thrombotic occlusion of the coronary artery (one patient). In conclusion, the morphologic changes after angioplasty are varied. These changes illustrate the mechanisms of angioplasty and some of the complications that can be expected in a small number of cases. The morphologic changes associated with coronary angioplasty are similar in patients undergoing elective or emergency angioplasty although medial dissection was not observed in these patients with an evolving myocardial infarction.     

Surgical versus non-surgical management of patients soon after acute myocardial infarction

Of 510 patients admitted to hospital with acute myocardial infarction, 34 had coronary artery bypass grafting before discharge (6-43 days (median 20) after infarction). The patients who were given grafts generally had a smaller infarction with less functional impairment than the 476 patients who were not. The outcome of coronary artery bypass grafting was investigated in a retrospective matched pair study. Patients were matched on the basis of the presence of postinfarction angina, left ventricular ejection fraction, location of the infarction, peak creatine kinase activity, Killip clinical class, and severity of coronary disease with 34 patients who were given medical treatment only. At one year follow up fewer of the operated patients had symptoms than did the matched non-operated patients. Survival at one year in the operated and non-operated groups respectively was 94% vs 91%; angina within one year occurred in 3% vs 68%; congestive heart failure in 3% vs 6%; and 0% vs 32% were referred for later bypass grafting or coronary angioplasty. It is concluded that coronary artery bypass grafting can be performed safely soon after myocardial infarction provided that left ventricular function is not seriously compromised. Such treatment is more effective than medical treatment for relief of angina during the first year after infarction.     

Complications prior to revascularization among patients waiting for coronary artery bypass grafting and percutaneous transluminal coronary angioplasty

AIM: To describe the occurrence of death, development of acute myocardialinfarction and need for hospitalization among patients on thewaiting list for coronary artery by pass grafting and percutaneoustransluminal coronary angioplasty. PATIENTS AND METHODS: All the patients on the waiting list for possible coronary revascularizationin September 1990 in western Sweden. RESULTS: Of 718 patients waiting for either coronary artery bypass graftingor percutaneous transluminal coronary angioplasty, 15 (2.1%)died between the actual week in September 1990 and prior torevascularization and 12 (1.7%) developed a non-fatal acutemyocardial infarction during the same period. All 15 patientswho died before undergoing revascularization died a cardiacdeath. Death and/or the development of an acute myocardial infarctionwas significantly more frequent among the elderly, among patientswith a low ejection fraction and among patients with a historyof diabetes mellitus. In all, 29% required hospitalization priorto the procedure. The most common reason was symptoms of anginapectoris requiring hospitalization in 23% of the patients. CONCLUSION: Among patients on the waiting list before either coronary arterybypass grafting or percutaneous transluminal coronary angioplasty,15 (2.1%) died prior to the procedure and 1.7% developed a non-fatalacute myocardial infarction. The risk of either death or developingan acute myocardial infarction was highest among patients inthe older age groups, among patients with a history of diabetesmellitus and among patients with a lower ejection fraction.     

Surgical versus non-surgical management of patients soon after acute myocardial infarction.

Of 510 patients admitted to hospital with acute myocardial infarction, 34 had coronary artery bypass grafting before discharge (6-43 days (median 20) after infarction). The patients who were given grafts generally had a smaller infarction with less functional impairment than the 476 patients who were not. The outcome of coronary artery bypass grafting was investigated in a retrospective matched pair study. Patients were matched on the basis of the presence of postinfarction angina, left ventricular ejection fraction, location of the infarction, peak creatine kinase activity, Killip clinical class, and severity of coronary disease with 34 patients who were given medical treatment only. At one year follow up fewer of the operated patients had symptoms than did the matched non-operated patients. Survival at one year in the operated and non-operated groups respectively was 94% vs 91%; angina within one year occurred in 3% vs 68%; congestive heart failure in 3% vs 6%; and 0% vs 32% were referred for later bypass grafting or coronary angioplasty. It is concluded that coronary artery bypass grafting can be performed safely soon after myocardial infarction provided that left ventricular function is not seriously compromised. Such treatment is more effective than medical treatment for relief of angina during the first year after infarction.     

One-year follow-up after recombinant tissue plasminogen activator administered to patients with acute myocardial infarction

Of 106 patients seen within 4 h of chest pain with 107 episodes of acute myocardial infarction, nine died before or during hospitalization mainly from cardiogenic shock, and four died during the next year, three were sudden deaths. The 93 survivors were reviewed at a mean of 53 (range 49-70) weeks after infarction. Of these 93, 18 had had attempted angioplasty (successful in 12) and 15 had had coronary artery bypass grafting (including one patient who had coronary artery bypass grafting performed after unsuccessful angioplasty). The remaining 61 patients continued on medical therapy only. During the one-year follow-up two patients suffered reinfarction and a further 22 had one or more cardiac admissions, mostly for chest pain. At review, 22 patients had angina (16 New York Heart Association Grade I or II) and five dyspnoea (all NYHA Grade II). Forty-three patients were taking oral nitrates, 53 were receiving calcium antagonists, 54 were using betablocking agents and 73 used anti-platelet agents. However, many of these patients continued on anti-anginal therapy prophylactically after their myocardial infarction, without continuing chest pain. Thus after recombinant tissue plasminogen activator therapy and following hospital discharge the mortality rate for patients with acute myocardial infarction was four out of 97 (4.1%) and reinfarction rate among survivors was two out of 93 (2.2%). Although the incidence of cardiac symptoms was low this may be partly due to the high incidence of angioplasty and coronary artery grafting, together with the use of anti-anginal agents.     

High dose intravenous streptokinase in acute myocardial infarction--short and long term prognosis

Streptokinase (1 million international units) was given intravenously over 30 or 60 minutes to 50 patients four hours or less after the onset of acute myocardial infarction. All were aged less than or equal to 70 years and had 4 mm or greater ST segment elevation in anterior or inferior leads. Rapid (mean 95 min) ST segment resolution, which was taken to indicate reperfusion of the myocardium, occurred in 36 (72%) patients. In these 36 the average time from onset of symptoms to peak creatine kinase, creatine kinase MB, and myoglobin was 9.45 hours, whereas it was 17 hours in the 14 patients in whom indirect criteria did not indicate reperfusion. Reperfusion arrhythmias were invariably present and ventricular tachycardia developed in five patients and ventricular fibrillation in two. The infarct related artery was seen to be open in 28 (70%) of the 40 patients who had delayed coronary arteriography. The frequency of patency in the infarct related artery was no different in patients given streptokinase less than 2 hours or between 2-4 hours from onset of symptoms nor did it differ when streptokinase was infused over 30 or 60 minutes. Mean left ventricular ejection fraction was 57% in those with a patient infarct related artery and 48% in those with an occluded vessel. Eight patients subsequently underwent elective percutaneous transluminal coronary angioplasty after successful thrombolysis and six had coronary artery bypass grafting. There were nine in-hospital reocclusions of the infarct related coronary arteries. Two bleeding episodes occurred; one required transfusion. Five of the 50 patients died in hospital. All of them had had an anterior myocardial infarction; four had bifascicular block and one had right bundle branch block. During follow up, four patients died, two suddenly and two from reinfarction. During follow up (mean 15 months) the frequency of reinfarction, dyspnoea, and angina was low and there was no difference in the proportions of patients returning to work between those with an open infarct related artery and those with a closed infarct related artery. Intravenous administration of high dose streptokinase to selected patients during the acute phase of myocardial infarction is a safe, effective, and practical method of thrombolysis. It must, however, be followed by coronary arteriography to select those patients in whom percutaneous transluminal coronary angioplasty or coronary artery bypass grafting will be helpful.     

Outcome following emergency coronary artery bypass grafting for failed elective balloon coronary angioplasty in patients with prior coronary bypass

To assess frequency and outcome of emergency coronary artery bypass grafting (CABG) for failed coronary angioplasty in patients with prior CABG, 2,136 elective angioplasty procedures in prior CABG patients were reviewed over a 10-year period. Emergency surgical revascularization was required in 19 patients (0.9%) with prior CABG, compared with 130 of 6,974 patients (1.9%) without prior CABG (p = 0.001). The interval from the most recent CABG to the failed coronary angioplasty was 6.8 years (range 1 to 16). Referral for emergency CABG was made on the basis of an acute closure not responding to repeat dilatation in 12 native coronary arteries and in 7 saphenous vein grafts. Severe hemodynamic instability after acute closure required the placement of an intraaortic balloon pump in 3 patients, including 2 who required cardiopulmonary resuscitation. A total of 34 saphenous vein grafts and 1 internal mammary artery graft were placed emergently. Three patients with high-risk features (3 prior CABG operations in 1 patient, single remaining vessel to heart in 2 patients) could not be weaned from cardiopulmonary bypass. The remaining 16 patients were discharged after a mean hospital stay of 16 days. Four patients developed new Q waves after CABG. At follow-up (mean 52 months, range 3 to 99), 1 patient died late from an acute myocardial infarction. The 15 survivors had no or mild angina and were free of further CABG. Thus, emergency CABG after failed angioplasty in patients with prior CABG is required infrequently. In patients without extreme high-risk features, emergency repeat CABG can be accomplished with good hospital and long-term results.     

High dose intravenous streptokinase in acute myocardial infarction--short and long term prognosis.

Streptokinase (1 million international units) was given intravenously over 30 or 60 minutes to 50 patients four hours or less after the onset of acute myocardial infarction. All were aged less than or equal to 70 years and had 4 mm or greater ST segment elevation in anterior or inferior leads. Rapid (mean 95 min) ST segment resolution, which was taken to indicate reperfusion of the myocardium, occurred in 36 (72%) patients. In these 36 the average time from onset of symptoms to peak creatine kinase, creatine kinase MB, and myoglobin was 9.45 hours, whereas it was 17 hours in the 14 patients in whom indirect criteria did not indicate reperfusion. Reperfusion arrhythmias were invariably present and ventricular tachycardia developed in five patients and ventricular fibrillation in two. The infarct related artery was seen to be open in 28 (70%) of the 40 patients who had delayed coronary arteriography. The frequency of patency in the infarct related artery was no different in patients given streptokinase less than 2 hours or between 2-4 hours from onset of symptoms nor did it differ when streptokinase was infused over 30 or 60 minutes. Mean left ventricular ejection fraction was 57% in those with a patient infarct related artery and 48% in those with an occluded vessel. Eight patients subsequently underwent elective percutaneous transluminal coronary angioplasty after successful thrombolysis and six had coronary artery bypass grafting. There were nine in-hospital reocclusions of the infarct related coronary arteries. Two bleeding episodes occurred; one required transfusion. Five of the 50 patients died in hospital. All of them had had an anterior myocardial infarction; four had bifascicular block and one had right bundle branch block. During follow up, four patients died, two suddenly and two from reinfarction. During follow up (mean 15 months) the frequency of reinfarction, dyspnoea, and angina was low and there was no difference in the proportions of patients returning to work between those with an open infarct related artery and those with a closed infarct related artery. Intravenous administration of high dose streptokinase to selected patients during the acute phase of myocardial infarction is a safe, effective, and practical method of thrombolysis. It must, however, be followed by coronary arteriography to select those patients in whom percutaneous transluminal coronary angioplasty or coronary artery bypass grafting will be helpful.     

大隐静脉序贯桥行冠状动脉螺旋CT的中期随访结果

目的：评价冠状动脉旁路移植术中应用大隐静脉序贯桥的中期临床效果。方法: 对37例冠状动脉粥样硬化性心脏病患者以大隐静脉序贯桥行冠状动脉旁路移植术,其中男25例,女12例,年龄45-69岁,不稳定性心绞痛患者23例,陈旧性心肌梗塞患者10例,急性心肌梗塞患者4例,于术后2年行冠状动脉螺旋CT随访。结果：37例病人中,35例全部血管桥均通畅,有2例病人乳内动脉桥路通畅,大隐静脉血管桥闭塞,未予介入或手术干预。结论:大隐静脉序贯桥中期随访通畅率良好,虽有“一闭俱闭”的风险,但大多数不会导致心肌梗死。     

Acute coronary insufficiency. Review of 46 patients.

Forty-six patients admitted with acute coronary insufficiency are reviewed. All were investigated by coronary angiography; 4 had normal coronary arteries and are included in this study; the remainder had a distribution of coronary artery disease similar to other angina patients. The clinical and angiographic findings, management, and subsequent course of the other 42 patients are presented. Fourteen patients (33%) in whom rest pain persisted after 48 hours underwent emergency coronary angiography, with 3 deaths; of the surviving 11 who had acute saphenous vein bypass grafting, 2 died at operation and 3 had perioperative myocardial infarctions. Seventeen patients (41%) who initially improved required surgery within 6 months because of symptoms. Eleven patients (26%) were not operated on. It is concluded that acute coronary insufficiency is best managed initially by intensive medical therapy but a high proportion will require surgery later because of disabling angina. Early investigation and surgery are associated with a high mortality and incidence of myocardial infarction. Survivors of surgery are symptomatically improved and there is a low incidence of late infarction and death.     

Emergency coronary artery bypass surgery after intracoronary thrombolysis for evolving myocardial infarction

Sixteen patients underwent emergency coronary artery bypass surgery immediately after intracoronary streptokinase infusion for acute evolving myocardial infarction. Of these, 11 patients had 70% residual stenosis in the recanalised vessel, and in five thrombolysis was unsuccessful. There were no hospital deaths. All the patients sustained myocardial necrosis, the peak activity of creatine phosphokinase correlating with the time to reperfusion. Chest tube drainage (mean 960 ml) was significantly higher than for control patients but did not correlate with the total dosage of streptokinase. No patients had further myocardial infarction or developed recurrent angina. Selected patients may benefit from coronary bypass surgery after intracoronary streptokinase infusion. If necessary this may be performed immediately with low mortality and morbidity.     

Emergency coronary artery bypass surgery after intracoronary thrombolysis for evolving myocardial infarction.

Sixteen patients underwent emergency coronary artery bypass surgery immediately after intracoronary streptokinase infusion for acute evolving myocardial infarction. Of these, 11 patients had 70% residual stenosis in the recanalised vessel, and in five thrombolysis was unsuccessful. There were no hospital deaths. All the patients sustained myocardial necrosis, the peak activity of creatine phosphokinase correlating with the time to reperfusion. Chest tube drainage (mean 960 ml) was significantly higher than for control patients but did not correlate with the total dosage of streptokinase. No patients had further myocardial infarction or developed recurrent angina. Selected patients may benefit from coronary bypass surgery after intracoronary streptokinase infusion. If necessary this may be performed immediately with low mortality and morbidity.     

Emergency surgical revascularization in establishing myocardial infarctions. Treatment of subtotal coronary occlusions

The introduction of intracoronary thrombolysis as a treatment for myocardial infarction has led to an increase in the number of very early coronary angiographies carried out in the acute phase of myocardial infarction. These investigations can be performed without excessive risk. In some cases, severe stenosis with significant distal circulatory impairment without evidence of thrombosis is found. In these very early investigations, these findings may represent a "pre-thrombolic" lesion in an evolving myocardial infarction. Six cases of very severe pre-thrombolitic stenosis of the LAD were observed in a series of 67 coronary angiographies performed in the early stages of myocardial infarction. These six cases were selected on strict clinical, ECG and angiographic criteria. One patient was hospitalised with cardiogenic shock. The six patients underwent emergency coronary bypass surgery: average time from admission to coronary angiography was 55 minutes; average time from coronary angiography to surgery was 3 hours. These 6 pre-thrombolic lesions of the LAD were also associated with lesions of the left circumflex and right coronary arteries. There were no operative complications but two patients had stormy immediate postoperative periods. There was no hospital mortality. All patients were reinvestigated at 1 month and all grafts were shown to be patent. The left ventricular ejection fractions improved in 3 cases, remained unchanged in 2 cases, and deteriorated in 1 case (the patient with cardiogenic shock). These results suggest that emergency coronary bypass surgery is a rational treatment of pre-thrombolic coronary stenosis observed at early coronary angiography in patients with evolving myocardial infarction in order to preserve as much myocardial muscle as possible.     

Complications of emergency coronary angioplasty for acute myocardial infarction]

To assess the incidence and consequences of complications occurring during emergency percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction (AMI), we studied 347 patients who underwent PTCA within 24 hours after the onset of AMI. Acute occlusion occurred in 29 patients (8.4%), of whom 16 patients underwent successful repeat PTCA. All of them survived until hospital discharge. The in-hospital reocclusion rates of these 16 patients were comparable to those of patients who had not experienced acute occlusion (18.8 vs 12.8%, ns). In the remaining 13 patients, reperfusion were not successful after acute occlusion, and 6 died. Side branch occlusion occurred in 21 patients (6.1%). Left circumflex artery occlusion occurring during PTCA for the proximal left anterior descending artery was fatal in 3 patients. Right ventricular branch occlusion during PTCA for the middle of the right coronary artery resulted in intractable right ventricular infarction in one patient, and he died. Among 14 patients who underwent repeat angiography, 13 had a patent side branch which had been occluded during PTCA. One patient had coronary rupture and died. During PTCA of the proximal left anterior descending artery, acute occlusion of the artery without reperfusion or occlusion of the left circumflex artery was often fatal. However, the prognosis of acute occlusion was relatively good, if repeat PTCA was successful and most of the occluded side branches remained patent in the chronic state.     

Left main coronary artery stenosis: factors predicting cardiac events in patients awaiting coronary surgery

Although most patients with left main coronary artery stenosis undergo urgent coronary artery bypass grafting, limited information is available regarding the risk factors that might lead to cardiac events between angiographic diagnosis and surgery. We retrospectively reviewed 1,731 cases of coronary artery bypass grafting at our institution, 97 of which were performed in patients with significant (> or = 50%) left main coronary artery stenosis. These patients were placed in 1 of 2 groups: eventful waiting or uneventful waiting. We analyzed multiple preoperative variables, and the incidence of serious cardiac events (death, myocardial infarction, unstable angina, left ventricular failure, and life-threatening ventricular arrhythmias) during the waiting period between angiography and surgery Four patients (4.1%) experienced serious cardiac events while awaiting surgery (1 had non-ST-elevation myocardial infarction; 3 had life-threatening ventricular arrhythmias); none died. All the events occurred more than 24 hours after cardiac catheterization. Of the preoperative variables analyzed (acute coronary syndrome, age, history of diabetes, hypertension, hyperlipidemia, smoking, renal failure, severity of left main stenosis, right coronary artery involvement, ejection fraction, and use of intra-aortic balloon pump), only acute coronary syndrome predicted the incidence of preoperative cardiac events (P=0.001). The occurrence of severe cardiac events while patients await coronary artery bypass grafting is rare. Carefully selected patients with severe left main coronary artery stenosis can safely await surgery. Concomitant acute coronary syndrome and severe left main coronary artery stenosis indicate a high risk for cardiac events. Therefore, in patients with these conditions, emergency coronary artery bypass may be preferable.     

Acute anterior myocardial infarction due to aortosaphenous vein graft occlusion with very large thrombus burden

A 75-year-old man, with a previous history of myocardial infarction and three-vessel coronary artery bypass grafting, presented with an acute anterior ST-elevation myocardial infarction. The vein graft to the left anterior descending artery was occluded with heavy thrombus burden, and the other grafts were patent. After administering a bolus dose of tirofiban and then undergoing percutaneous coronary intervention without stenting to the left anterior descending artery saphenous vein graft, intracoronary thrombolytic infusion was performed to maintain the patency of the vein graft. The patient was asymptomatic after medical follow-up. This may be an effective treatment option in patients with large thrombus burden and requires further investigation through large-scale trials.     

Percutaneous transluminal coronary angioplasty in acute myocardial infarction

Percutaneous transluminal coronary angioplasty (PTCA) has, in general, been restricted to therapy for patients with angina pectoris. Thrombolytic therapy and guide wire recanalization have been used to recanalize coronary arteries in patients with evolving myocardial infarction. Recently we and others have examined the use of PTCA to recanalize the acutely occluded artery associated with the early evolving phase of myocardial infarction. PTCA was performed as definitive therapy in eight patients with acute myocardial infarction. Seven of these had totally occluded arteries to the region of infarct. The infarct-related artery was open within 20 minutes in each of these cases. PTCA recanalization resulted in evidence for reperfusion in each case. Residual stenoses either were not present or were minimal. The procedure was well tolerated. These preliminary results suggest that PTCA may be a reasonable alternative to intracoronary thrombolytic therapy in certain patients with acute evolving myocardial infarction.     

Percutaneous transluminal coronary angioplasty of native coronary arteries via saphenous vein grafts

We analyzed the immediate and long-term outcome of percutaneous transluminal angioplasty (PTCA) of native coronary arteries via saphenous vein grafts (SVG) in 30 patients. The mean age of the grafts was 69 months. Angioplasty was successful in 27 (90%) patients. One patient died following emergency bypass surgery. There were no distal embolizations and one non-Q myocardial infarction. Follow-up angiography was performed in 12 patients, which revealed restenosis in three patients. At a mean follow-up of 20 months, cumulative survival was 93%. Freedom from myocardial infarction, repeat bypass surgery, and death was 80%. We conclude that PTCA of native coronary arteries via SVG is a safe alternative to repeat CABG in selected patients.