Effect of intracoronary thrombolytic therapy on exercise-induced ischemia after acute myocardial infarction

Intracoronary streptokinase (SK) therapy increases vessel patency rate after acute myocardial infarction (AMI) and thus may lead to a greater exercise-induced myocardial ischemia. This hypothesis was tested in 39 patients enrolled in an angiographically randomized trial of intracoronary SK (19 treated with SK and 20 control subjects); all patients underwent thallium-201 scintigraphy at rest before acute angiography, as well as at rest and during stress 5 to 6 weeks after AMI. The patients were classified into 2 groups based on the presence (n = 13) or absence (n = 26) of complete obstruction of the infarct-related coronary artery at the end of the acute angiography. Semiquantitative score of myocardial thallium uptake was expressed as percent of maximal defect score. Thallium defect score at rest between admission and 5 to 6 weeks' study decreased from 10 +/- 16% units in the control group and from 23 +/- 14% units in the SK group (p = 0.01). This decrease was related to opening of the infarct-related artery (opening 23 +/- 16% vs occlusion 5 +/- 10%). The change in exercise-induced defect score was significantly (p = 0.01) larger in patients in the SK group (11 +/- 6% units) than in those in the control group (5 +/- 7% units). The perfusion defect during exercise was larger (p = 0.006) in patients with incomplete obstruction or reperfusion (10 +/- 6% units) than in patients with complete obstruction (3 +/- 7%). This difference was independent of the number of diseased coronary vessels.(ABSTRACT TRUNCATED AT 250 WORDS)     

Percutaneous transluminal coronary angioplasty after thrombolytic therapy: a prospective controlled randomized trial

In 162 patients with acute transmural myocardial infarction, combined intravenous and intracoronary thrombolytic therapy with streptokinase was initiated. In vessels that remained occluded, mechanical recanalization was performed with a 3F recanalization catheter (group I, n = 79) or a 4F Grüntzig balloon catheter (group II, n = 83). After reperfusion, intracoronary streptokinase was administered superselectively. After termination of streptokinase infusion, angioplasty was performed only in patients in group II. There was no difference between the groups in relation to sex, age, infarct location, creatine kinase levels and time between onset of symptoms and start of treatment. Initial coronary angiography showed an open vessel in 27 (34%) of 79 patients in group I and 21 (25%) of 83 patients in group II. The final reperfusion rate was 90% (71 of 79) in group I and 86% (71 of 83) in group II. Angioplasty was attempted in 69 of the 71 patients in group II with a success rate of 65% and an occlusion rate of 3%. During the hospital stay, reocclusion occurred in 14 (20%) of 71 patients in group I. After thrombolytic therapy, coronary luminal narrowing in group I was 75 +/- 17% in patients without and 87 +/- 6% in patients with reocclusion (p less than 0.05). In group II, reocclusion was found in 10 (14%) of 71 patients. After angioplasty, the degree of coronary stenosis in group II was reduced from 82 +/- 12 to 51 +/- 30% (p less than 0.001). Reocclusion was found in 3 (7%) of the 45 patients with successful angioplasty and in 7 (32%) of the 22 patients with unsuccessful angioplasty (p less than 0.01). Improvement in regional left ventricular function was observed only in patients from group II with anterior myocardial infarction. In conclusion, by combined medical and mechanical recanalization, the rate of coronary reperfusion can be increased and infarct time shortened, providing the possibility of full revascularization by angioplasty, with improvement of regional wall motion and reduction of the rate of reocclusion.     

Coronary perfusion during acute myocardial infarction with a combined therapy of coronary angioplasty and high-dose intravenous streptokinase

Two hundred and sixteen patients with acute myocardial infarction were treated with immediate infusion of high-dose (1.5 million units) intravenous streptokinase followed by emergency coronary angioplasty. The infarct lesion was crossed and dilated in 99% and persistent coronary perfusion after the procedure was achieved in 90% (including 3% with significant residual stenosis). Total in-hospital mortality was 12%. Multivariable analysis showed a higher hospital mortality with cardiogenic shock (41% vs 5% without shock), older age, lower left ventricular ejection fraction, and female sex. Final patency of the infarct-related vessel was determined by follow-up in-hospital cardiac catheterization. Coronary reocclusion occurred in 11% (symptomatic in 7%, treated with emergency angioplasty or bypass surgery; silent in 4%, treated medically). Of the surviving patients with successful initial establishment of infarct vessel patency, 94% were discharged from the hospital with an open infarct artery or a bypass graft to the infarct vessel. There was significant improvement in both ejection fraction (44% to 49%; p less than .0001) and regional wall motion in the infarct zone (-3.0 SD to -2.4 SD; p less than .0001) among patients with persistent coronary perfusion and insignificant residual stenosis at the time of the follow-up cardiac catheterization. Thus, a treatment strategy for acute myocardial infarction that includes immediate administration of streptokinase followed by emergency coronary angioplasty, and coronary bypass surgery when necessary, results in a high rate of early and sustained patency of the infarct-related vessel.     

Quantitative measurement of coronary flow during medical revascularization (thrombolysis or angioplasty) in patients with acute infarction

This study quantitatively evaluated the change in myocardial blood flow resulting from medical revascularization in patients with acute anterior myocardial infarction. Changes in great cardiac vein flow were measured using a thermodilution technique in 13 patients with acute infarction; 3 received intracoronary streptokinase and 10 percutaneous transluminal angioplasty. Average great cardiac vein flow during left anterior descending coronary artery occlusion was 62 +/- 6 ml/min and increased to 70 +/- 7 ml/min (p = 0.039) after arterial recanalization. There was significant individual variability in the great cardiac vein flow increments that was highly predictive of functional recovery as expressed by the change in ejection fraction at 7 to 10 days (r = 0.93, p = 0.0008). Incremental great cardiac vein flow was inversely correlated with the degree of residual stenosis and the duration of ischemia (r = 0.88, p = 0.0007). Patients with residual stenosis less than or equal to 50% had a significantly larger increase in great cardiac vein flow (14 +/- 5 ml/min) than did those with residual stenosis greater than 50% (0 +/- 2 ml/min, p = 0.026). Neither preinterventional left ventricular ejection fraction, hemodynamics nor age predicted incremental great cardiac vein flow. Therefore, quantitative measurements of great cardiac vein flow during medical revascularization in patients with an acute anterior myocardial infarction demonstrate variable reflow that is physiologically significant. A high grade residual stenosis and prolonged period of ischemia limit large increases in flow and prevent functional recovery. This study emphasizes the fact that recanalization in itself cannot be used as an indicator of the success of interventions designed to produce myocardial reperfusion.     

Quantitative and qualitative effects of intracoronary streptokinase in unstable angina and non-Q wave infarction

Thrombolytic therapy has been shown to be effective in reopening totally occluded arteries in acute myocardial infarction. Coronary thrombus is also believed to play a role in the pathophysiology of unstable angina and non-Q wave infarction. However, few patients with these two acute coronary syndromes have been treated with intracoronary streptokinase. Therefore, 100,000 to 300,000 IU (mean 177,000 +/- 80,000 IU) of intracoronary streptokinase was infused into 36 consecutive catheterized patients who either presented with an acute episode of unstable angina or had had a recent non-Q wave infarction and in whom a less than 100% occluded ischemia-producing artery could be identified. Qualitative techniques utilizing vessel magnification and quantitative analysis with digital subtraction were performed on the ischemia-producing coronary lesion before and immediately after streptokinase therapy and 3 to 10 days later in 18 patients who were restudied at the time of transluminal coronary angioplasty. Before streptokinase treatment, 24 (67%) of 36 ischemia-producing arteries contained eccentric, irregular lesions. The percent diameter stenosis and percent area stenosis in all ischemia-producing arteries averaged 83.8 +/- 8.3% and 94.8 +/- 3.3%, respectively. After streptokinase treatment there were 23 arteries (64%) with eccentric irregular lesions. The percent diameter stenosis and percent area stenosis in all ischemia-producing arteries were similar to pre-streptokinase values (82.9 +/- 5.9% and 93.8 +/- 4.0%, respectively). At restudy, there were also no significant changes in any quantitative or qualitative variable. Five individual patients showed a significant reduction in percent stenosis after streptokinase. This improvement was independent of duration of symptoms, use of heparin before angiography, streptokinase dose or reduction of fibrinogen levels post-streptokinase. Two additional patients deteriorated clinically and developed total occlusion of the ischemia-producing artery within 12 hours of streptokinase infusion. These data suggest that intracoronary streptokinase may be of limited utility in either unstable angina or recent non-Q wave infarction with a less than 100% occluded ischemia-producing artery. In these syndromes, thrombus may be organized or short infusions may be given too late to be effective. In some cases, thrombus may even be absent. Whether longer infusion of streptokinase or other thrombolytic agents will be of benefit remains to be determined.     

Clinical and angiographic follow-up after coronary recanalization during acute myocardial infarction

Coronary angiography followed by percutaneous transluminal coronary angioplasty and/or intracoronary streptokinase infusion was performed in 50 patients 288 +/- 162 min after the onset of symptoms of acute myocardial infarction. Subocclusion of the infarct-related vessel was found in 5 patients, all of whom had angioplasty of the residual stenosis. Recanalization was achieved in 37 patients (success rate 82%). There was no procedure-related death. One patient died 4 days after the intervention. Control coronary angiography 5 +/- 2 months after the procedure in 35 of 42 patients with recanalization documented recurrence of stenosis or reocclusion in 8 (23%). Comparison of preintervention and control angiograms in 33 patients showed an increase in left ventricular ejection fraction from 55 +/- 8 to 61 +/- 13%, p less than 0.001, in patients with collaterals to the infarct-related vessel and/or recanalization within 180 min after the onset of pain, and from 55 +/- 9 to 59 +/- 8%, nonsignificant, in patients with recanalization later than 180 min and without collaterals. At follow-up 7 +/- 4 months after the procedure, 1 patient had died and 36 (86%) were asymptomatic. Good long-term results can be achieved at a reasonable risk by coronary angioplasty with or without thrombolysis in evolving myocardial infarction. Left ventricular function is better preserved in patients with collaterals and/or early recanalization.     

Early reocclusion after in situ coronary desobstruction either with streptokinase or angioplasty during the acute phase of myocardial infarction

The aim of this study was to assess the incidence of early reocclusion after therapeutic reperfusion of coronary arteries in acute myocardial infarction. Seventy four patients underwent intracoronary thrombolysis and 133 patients had immediate coronary angioplasty. The success rates were 70 per cent and 86 per cent respectively (p less than 0.01) and the degree of residual stenosis was 77 +/- 13 percent and 25 +/- 15 per cent respectively (p less than 0.001). The patients in whom coronary reperfusion was successful, 52 after in situ thrombolysis, 48 after angioplasty alone, and 66 after combined angioplasty and intravenous thrombolysis, underwent coronary arteriography 24 to 36 hours later. Reocclusion was asymptomatic in 46 per cent of cases (13/28) and its prevalence was 16.9 per cent: 25.5 per cent for the right coronary compared with 12.8 per cent for the left anterior descending (p less than 0.05) and 11.7 per cent for the left circumflex artery; reocclusion occurred in 8.6 per cent of patients treated before the 3rd hour compared with 22.9 per cent of patients receiving treatment after the 3rd hour (p less than 0.05). The incidence of reocclusion was 17.3 per cent after intracoronary thrombolysis and 16.7 per cent after angioplasty (angioplasty alone 18.7 per cent; associated with thrombolysis 15.2%). The degree of residual stenosis was nil after intracoronary thrombolysis and 16.3 per cent after angioplasty when the stenosis was insignificant, and 20.5 per cent and 18.8 per cent respectively with stenotic lesions greater than 50 per cent.     

Impact of different reperfusion modalities on ventricular function after acute myocardial infarction

Single-plane contrast ventriculography was performed on admission and before hospital discharge in more than 200 patients with acute myocardial infarction participating in a series of prospective clinical trials including intracoronary streptokinase, percutaneous transluminal coronary angioplasty (PTCA), intravenous tissue plasminogen activator (rt-PA) and thrombolysis (intravenous rt-PA or streptokinase) followed by PTCA. Both global ejection fraction (EF) and regional wall motion of the infarct zone were measured to assess serial changes. Patients treated with intracoronary streptokinase 3.6 +/- 1.8 hours after symptom onset had no increase in EF (mean change 1 +/- 6%, difference not significant [NS]), but patients treated with primary PTCA at 3.0 +/- 1.2 hours did (mean improvement 8 +/- 7%, p less than 0.001). Patients treated with sequential intravenous streptokinase and PTCA 2.6 +/- 1.3 hours after symptom onset showed similar improvement in EF (mean change 6 +/- 12%, p less than 0.002). Patients treated with rt-PA had no change in EF whether treated with rt-PA alone or rt-PA followed by immediate angioplasty (mean change -2 +/- 8% and 0.5 +/- 8%, p = NS, respectively). When angioplasty was used in patients with persistent occlusion after thrombolytic therapy, EF improved in those who had received intravenous streptokinase (mean change 10 +/- 7%, p less than 0.002), but not those who had received rt-PA (+0.5%, p = NS). However, infarct zone regional wall motion improved in patients treated with intracoronary streptokinase (+0.59 +/- 0.79 standard deviation/chord, p less than 0.05), primary PTCA (+1.32 +/- 1.32, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Treatment by redilatation and thrombolysis of occlusion occurring during percutaneous coronary angioplasty

In patients who develop acute coronary occlusion during or after percutaneous coronary angioplasty, surgery is not mandatory, and other treatments may be considered, namely redilatation and/or thrombolysis. Between June, 1984 and January, 1988 we performed 500 dilatations of coronary arteries, not counting the attempts made in the acute phase of myocardial infarction. Acute coronary occlusion without angiographic image of occlusive dissection occurred in 31 patients (6.2%) and was treated by attempted redilatation and intracoronary thrombolysis. In 10 patients (group A) either the occlusion could not be removed and emergency surgery was tried (5 cases with 2 infarctions and 1 death), or the occlusion was removed but myocardial infarction took place (5 cases). In 21 patients (group B), the occlusion was removed and the outcome was favourable without myocardial infarction. Altogether, myocardial infarction or death occurred in only 8 cases, or 26% of acute occlusions. The clinical and angiographic features of the two groups before and after angioplasty were compared; two of them differentiated group A from group B: (1) unstable angina, 7/10 in group A, 4/21 in group B (p less than 0.01), and (2) degree of stenosis, 93.1% in group A, 78% in group B (p less than 0.01). When coronary occlusion occurs during or after coronary angioplasty and is poorly tolerated with fall in blood pressure, surgery must be contemplated at once, even after recanalization of the vessel and subsidence of ischaemia. In all other cases, treatment with both redilatation and thrombolysis should restore the benefits of angioplasty without myocardial infarction.     

Recurrence of stenosis after first and repeat coronary angioplasty. Clinical and angiographic follow-up

The incidence of restenosis after initially successful first coronary angioplasty and the long-term effectiveness of repeat angioplasty for recurrence were examined on the basis of data on 282 consecutive patients with successful angioplasty. Primary success of first coronary angioplasty was obtained in 86% of patients and major complications (death, acute myocardial infarction and emergency coronary bypass surgery) occurred in 5% of patients. Control coronary angiography 10 +/- 6 months after successful angioplasty in 195 patients documented recurrence of stenosis in 33%. Repeat angioplasty was attempted in 52 patients with a primary success of 92%. One patient sustained an acute infarction as a complication of the procedure (2%). Control coronary angiography 7 +/- 4 months after a successful second procedure in 28 patients documented a second recurrence of stenosis in 39%. Recurrence rates after first and second coronary angioplasty were comparable (33 vs 39%, ns) but, for lesions of the left anterior descending coronary artery, recurrence was observed more frequently after second than after first angioplasty (47 vs 31%, p less than 0.05). Restenosis after second angioplasty, but not after first, was more frequent in women than in men. Patients with second recurrence were older than those with continuing angiographic success (59 +/- 8 vs 50 +/- 12 years, p less than 0.05). Recurrence was treated by a third coronary angioplasty in 5 patients, with success in all. Clinical follow-up 8 +/- 6 months after the last successful procedure was available for all 43 patients with repeat angioplasty who did not cross over to coronary surgery.(ABSTRACT TRUNCATED AT 250 WORDS)     

Intracoronary thrombus in syndromes of unstable myocardial ischemia

The association of coronary thrombosis and transmural myocardial infarction is well documented. We have recently observed apparent intracoronary thrombl in patients with unstable myocardial ischemia without transmural infarction. To assess the frequency and angiographic characteristics of intracoronary defects consistent with thrombi, we reviewed the angiograms of all patients undergoing catheterization within 1 month of the onset of unstable angina or the intermediate coronary syndrome. Of 129 such patients, eight (6.2%) had nonoccluding, hazy, or nonopacified intracoronary filling defects consistent with thrombus in angiographically well-opacified vessels. All defects were just distal to a significant (80% to 99%) coronary stenosis. In each instance the thrombus-involved vessel supplied a myocardial segment referable to the electrocardiographically defined area of ischemia. Support for the theory that the intracoronary defects were thrombi includes three patients with enlargement of the filling defects, who underwent repeat angiography within 7 days, and two patients with embolization of defect fragments. Furthermore these defects were angiographically similar to poststenotic intraluminal defects seen transiently in some patients after partial intracoronary streptokinase recanalization. In conclusion, we have observed, angiographically, intracoronary filling defects consistent with thrombus in some patients with unstable myocardial ischemia.     

Results of coronary surgery after failed elective coronary angioplasty in patients with prior coronary surgery

The results of coronary artery bypass surgery after failed elective coronary angioplasty in patients who have undergone prior coronary surgery are unknown. Coronary angioplasty may be performed to relieve angina after surgery either to the native coronary vessels or to grafts. Failure of attempted coronary angioplasty may mandate repeat coronary surgery, often in the setting of acute ischemia. From 1980 to 1989, 1,263 patients with prior coronary bypass surgery underwent angioplasty; of these patients, 46 (3.6%) underwent reoperation for failed angioplasty during the same hospital stay. Of the 46 patients who underwent reoperation, 33 had and 13 did not have acute ischemia. In the group with ischemia, 3 patients (9.1%) died and 14 (42.4%) died or had a Q wave myocardial infarction in the hospital compared with no deaths (p = NS) and no deaths or Q wave myocardial infarction (p = 0.005) in the group without ischemia. At 3 years, the actuarial survival rate was 88 +/- 6% in the group with ischemia, whereas there were no deaths in the group without ischemia (p = NS), and freedom from death or myocardial infarction was 51 +/- 10% in the group with ischemia, versus no events in the group without ischemia (p = 0.006). In most patients with prior coronary bypass surgery, coronary angioplasty was performed without the need for repeat coronary bypass surgery. Should coronary angioplasty fail, reoperation in patients without acute ischemia can be performed with overall patient survival comparable to that of elective reoperative coronary bypass without coronary angioplasty.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of fibrinolysis and percutaneous transluminal coronary angioplasty on the frequency of ventricular premature complexes

This study evaluated the aggressive management of acute myocardial infarction to determine how it modifies the incidence of ventricular arrhythmias and of other determinants of prognosis during recovery. The population consisted of 344 consecutive survivors of acute myocardial infarction admitted to the hospital with chest pain and ST-segment elevation on the electrocardiogram. Three groups constituted the study population: 168 control patients treated conservatively or in whom fibrinolysis was unsuccessful, 73 patients successfully reperfused with intravenous streptokinase and 103 patients with both successful fibrinolysis and successful percutaneous transluminal coronary angioplasty (PTCA) of the artery responsible for the infarct. Early spontaneous angina occurred in 47 control patients (28%), 25 streptokinase patients, (34%) and, in significantly fewer number, 20 PTCA patients (19%, p less than 0.05). Similarly, exercise-induced ST-segment depression on the predischarge exercise treadmill test was less frequent with PTCA (p less than 0.05). The number of ventricular premature complexes (VPCs) on a 24-hour Holter recording was 40 +/- 123/hr in the control group and significantly less in the streptokinase (21 +/- 64, p less than 0.05) and PTCA groups (17 +/- 61, p less than 0.05). Three or more VPCs/hr were observed in 50% of the control patients, compared with 29% of the streptokinase and 27% of the PTCA patients (p less than 0.005). Mean radionuclide ejection fraction was greater than 40% and similar in the 3 study groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Usefulness of coronary angioplasty in asymptomatic patients

Of 6,545 patients who had elective coronary angioplasty procedures performed over a 7.5-year period from June 1980 through December 1987, 114 (1.7%) never had symptoms of myocardial ischemia. Exercise-induced silent myocardial ischemia was documented before angioplasty in 94% of these asymptomatic patients. Angioplasty was successful in 87%, whereas emergency coronary artery bypass grafting was required in 4%, and a further 2% had myocardial infarctions after the procedures. The remaining 7% had unsuccessful angioplasty procedures but experienced no in-hospital cardiac events. The follow-up period after hospital discharge averaged 43 +/- 20 months (range 5 to 93). There were no deaths. In the group of 99 patients with initially successful angioplasty procedures the follow-up interval ranged from 5 to 92 months. During that period, 7 patients underwent coronary bypass surgery, 4 patients had myocardial infarction and 30 patients had repeat angioplasty procedures for restenosis. The cumulative probability of event-free survival over 5 years for the group with successful angioplasty was: 100% freedom from death, 95% freedom from myocardial infarction, 87% freedom from myocardial infarction or coronary bypass surgery and 61% freedom from myocardial infarction, coronary bypass surgery or repeat angioplasty. Thus, coronary angioplasty performed in 114 asymptomatic patients, most with exercise-induced silent myocardial ischemia, achieved very good primary success and was accompanied by low cardiac event rates and no deaths over several years of patient follow-up.     

Coronary vessel stent implantation in patients with symptomatic dissections following balloon dilatation

Dissections after coronary balloon angioplasty are risk factors for acute or subacute vessel closure. Intracoronary stenting was developed to avoid this complication by wrapping the intimal and medial flaps against the vessel wall, which reduces the risk of acute thrombosis. A total of 17 stents were implanted into the coronary arteries of 10 patients with angiographically documented dissections after balloon angioplasty, who presented angina and ischemic ECG changes. Mean minimal stenosis diameter was 1.11 +/- 0.35 mm (65.1%) before, and 1.48 +/- 0.56 mm (53.9%, n.s.) and 2.45 +/- 0.62 mm (23.5%, p less than 0.005), respectively, after balloon angioplasty with and without taking the dissection membrane into account. All patients reported an immediate recovery of their anginal complaints after stent delivery, and ischemic ECG changes disappeared. The mean residual stenosis after coronary stenting was measured as 3.33 +/- 0.23 mm (0%, p less than 0.001). The immediate control angiograms and these after 24 h depicted smooth vessel walls without any irregulations at the site of implantation, and the mean residual stenosis diameter remained unchanged after 24 h (3.3 +/- 0.23 mm; 1.2%, p less than 0.001). No patient suffered acute myocardial infarction, one patient underwent coronary bypass surgery because of persisting episodes of angina pectoris. Thus, intracoronary stenting seems to be a secure and effective method to handle dissections after balloon angioplasty, and perhaps reduces the rate of acute complications and the need for emergency bypass surgery after coronary balloon angioplasty.     

Prospective randomized trial of intravenous and intracoronary streptokinase in acute myocardial infarction

To evaluate the relative thrombolytic efficacy and complications of intracoronary vs high-dose, short-term intravenous streptokinase infusion in patients with acute myocardial infarction, we performed baseline coronary arteriography and then randomly allocated 51 patients with acute myocardial infarction to receive either intracoronary (n = 25) or intravenous (n = 26) streptokinase. Patients getting the drug by the intracoronary route received 240,000 IU of streptokinase into the infarct-related artery over 1 hr, whereas those getting the drug by the intravenous route received either 500,000 IU of streptokinase over 15 min (n = 10) or 1 million IU of streptokinase over 45 min (n = 16). Angiographically observed thrombolysis occurred in 76% (19/25) of the patients receiving intracoronary streptokinase, in 10% (1/10) of the patients receiving 500,000 IU of streptokinase intravenously, and in 44% (7/16) of the patients receiving 1 million IU of streptokinase intravenously. Among patients in whom thrombolysis was observed, mean elapsed time from onset of streptokinase infusion until lysis was 31 +/- 18 min in patients receiving intracoronary streptokinase and 38 +/- 20 min in those receiving intravenous streptokinase (p = NS). Among patients in whom intravenous streptokinase "failed," intracoronary streptokinase in combination with intracoronary guidewire manipulation recanalized only 7% (1/15). Fibrinogen levels within 6 hr after streptokinase were significantly lower in the patients receiving intravenous streptokinase (39 +/- 17 mg/dl) than the levels in those receiving intracoronary streptokinase (88 +/- 70 mg/dl) (p less than .05) but were similar 24 hr after streptokinase in the two groups. Bleeding requiring transfusion occurred in one patient in each group. Thus, in this prospective randomized trial of intracoronary vs intravenous streptokinase, hemorrhagic complications were few, although both regimens produced a systemic lytic state. Although the thrombolytic efficacy of intracoronary streptokinase was superior to that of high-dose, short-term intravenous streptokinase, the higher-dose intravenous regimen (1 million IU over 45 min) achieved thrombolysis in a significant minority (44%) of patients and might be useful therapy for patients not having access to emergency catheterization.     

Coronary angioplasty. Results observed in 14 cases

Between December, 1985, and May, 1988 we have performed coronary angioplasty of 14 lesions in 12 patients. Before angioplasty 8 patients had a history of unstable angina, and 3 developed angina after streptokinase because of an acute myocardial infarction. We attempted angioplasty of 11 proximal and 3 distal lesions; these included a coronary bypass graft lesion, and 3 lesions in one vessel. We successfully dilated 12 lesions (85%). The coronary stenosis was reduced on average from 84.2 +/- 9 to 17.5 +/- 7 per cent (P less than 0.0001); and the pressure gradient was reduced from 74 +/- 16.25 to 18.3 +/- 9 mmHg (P less than 0.001). Procedure-related complications included: coronary occlusion in 4 patients (28.5%) that were successfully resolved during angioplasty in 3 patients, but one developed myocardial infarction (8.3%); and one urgent surgery and death in a patient with 3 vessel disease. Twelve patients (83%) with no evidence of myocardial ischemia returned to their normal activities. These initial data confirm coronary angioplasty as a safe, efficatious and successful alternative in the management of selected patients with coronary artery disease.     

Management comparison for acute myocardial infarction: direct angioplasty versus sequential thrombolysis-angioplasty

To compare the results and outcome of different management approaches for acute myocardial infarction, we analyzed our experience with early (i.e., within 6 hours of infarct onset) direct percutaneous transluminal coronary angioplasty (group A) versus initial treatment with thrombolytic therapy (group B) followed by angioplasty. From 1982 to 1989 a total of 214 patients underwent primary angioplasty for acute myocardial infarction. During this time 157 patients underwent initial thrombolytic therapy, 104 with intravenous streptokinase and 53 with intravenous tissue-type plasminogen activator followed by angioplasty. Other than age (group A, 61.7 +/- 11.5 years; group B, 57.3 +/- 11.6 years; p = 0.0002), the clinical characteristics of the groups were similar. In group A, 197 (92.1%) had successful results, and 17 (7.9%) were failures. Of the group treated with thrombolytic therapy, there was an overall 81.5% patency rate for patients treated with streptokinase and tissue-type plasminogen activator with no significant difference between the agents. Angioplasty success after thrombolytic therapy was 94.3%. In-hospital and 1-year survival was significantly better in group B patients (95.5% and 95.5%, respectively) than in group A patients (92.1% and 89.3%, respectively). We conclude that both direct angioplasty and thrombolytic therapy followed by angioplasty provide high recanalization rates but that short- and long-term survival is improved when thrombolytic therapy precedes angioplasty in acute myocardial infarction patients.