SMART: The microstent's ability to limit restenosis trial.

In this randomized, prospective, multicenter trial (n = 661) of patients with de novo or restenotic coronary lesions, 330 patients received the MicroStent(R) II (MSII), and 331 received the Palmaz-Schatz (PS) stent. The short-term procedural success rates were 94.4% and 95.7%, respectively (P = 0.47). The 30-day cumulative incidence of major adverse events [death, myocardial infarction, CVA, target lesion revascularization (TLR)] was 6.4% for the MSII and 4.5% for the PS stent (P = 0.31). The in-stent binary restenosis rate at 6 months was 25.2% for the MSII and 22.1% for the PS stent (P = 0.636). Using Kaplan-Meier estimates, the incidence of clinically driven TLR was 8.9% for the MSII and 9.2% for the PS stent at 180 days; at 270 days, it was 12.8% and 12.1%, respectively (P = 0.83). MSII and the PS stents were comparable with respect to short-term procedural success, complications, and late clinical and angiographic restenosis.

Role of coronary artery bypass surgery after intracoronary streptokinase infusion for myocardial infarction.

Intracoronary streptokinase infusion has been shown to improve left ventricular function and reduce hospital mortality in patients with acute myocardial infarction. Adjuvant coronary artery bypass surgery is of value in many of these patients who have recurrent angina, circulatory instability, severe coronary artery occlusive disease, or a high risk of reinfarction. There is little, if any, evidence that immediate coronary artery bypass surgery affects the results adversely--either because of recent myocardial infarction or recent streptokinase infusion, and early operation appears to be a safe and worthwhile modality of treatment in this group of patients with myocardial infarction.

Sustained improvement in left ventricular function and mortality by intracoronary streptokinase administration during evolving myocardial infarction.

One hundred eighty-eight patients with acute myocardial infarction were studied prospectively from August 1980 to September 1982. One hundred thirty-six of these patients were entered into a intracoronary streptokinase study after informed consent was obtained. The remaining 52 patients, who either met exclusion criteria for the study or refused to participate, served as a control group and were treated as those in the study group except that they did not undergo emergency cardiac catheterization. Left ventricular function was determined in both groups by gated radionuclide ejection fraction (EF) on admission to the hospital, at discharge, and 6 months after discharge. With successful reperfusion up to 18 hr after onset of chest pain, mean left ventricular function in the study group improved (EF 39 +/- 13% on admission and 46 +/- 12% at discharge; p less than .001). Mean EF in control patients and those not achieving reperfusion did not change from admission to discharge. Mean EF at 6 month follow-up was not significantly different than at discharge in the study group or the control group. Total cardiac mortality in the control group was 19% compared with 10% in the study group (p = .06, NS). When patients admitted in pulmonary edema or shock (Killip class III or IV) were excluded from both groups, total cardiac mortality in the study group was significantly lower (4%) compared with in the control group (12.5%, p less than .05. The administration of intracoronary streptokinase during evolving myocardial infarction up to 18 hr after onset of chest pain may result in decreased mortality and sustained improvement in left ventricular function.

Streptokinase reperfusion and early surgical revascularization in patients with acute myocardial infarction.

During a 21-month period, 150 patients with acute myocardial infarction were offered entry into a study comprising emergency cardiac catheterization, streptokinase infusion for thrombus if present, and coronary artery bypass surgery where appropriate. Forty refused or were excluded, and served as a control group. Approximately 80% of the remainder had coronary thrombosis and obtained benefit as a group from streptokinase reperfusion. Among the 44 who had coronary artery bypass mortality was low except in those having cardiogenic shock at the time of operation. Those without coronary thrombosis appeared to have a better result from early than from delayed operative revascularization. It appears that both streptokinase reperfusion and early coronary artery bypass have a beneficial role in the management of patients with acute myocardial infarction.

Beneficial effects of intracoronary thrombolysis up to eighteen hours after onset of pain in evolving myocardial infarction.

Coronary arteriography and intracoronary streptokinase (STK) infusion were performed on 89 patients with evolving acute myocardial infarction (AMI). Ventricular function was followed in these patients during their hospitalization by gated radionuclide ventriculography. In 35 of these patients thallium imaging was performed on admission and 4 hours after reperfusion. An additional 30 patients with AMI who either met exclusion criteria for the STK protocol or refused study served as a control group. In patients admitted 0 to 6, 6 to 12, or 12 to 18 hours after onset of pain, there was no difference in change in left ventricular ejection fraction (LVEF) from admission to discharge, in percent of patients with total occlusion demonstrating reperfusion, or in percent of patients demonstrating a significant increase in LVEF. The average increase in LVEF from admission to discharge in patients reperfused ws 8% (40% +/- 14% to 48% +/- 13%, p less than 0.001). No change in LVEF was demonstrated in the control population or in patients in whom coronary reperfusion was unsuccessful. Reperfusion produced an increase in thallium uptake in the infarct-related myocardium that was accompanied by an improvement in regional function. Failure of reperfusion produced no change in either thallium uptake or regional function.

Coronary artery reperfusion in acute myocardial infarction: beneficial effects of intracoronary streptokinase on left ventricular salvage and performance.

Coronary angiography was performed on hospital admission in 37 patients with acute myocardial infarction (AMI). Thirty patients had total occlusion of the infarct-related coronary artery and seven patients had severe proximal stenoses with poor distal flow. In 20 of 30 patients with total occlusion, intracoronary (IC) infusion of streptokinase (SK) resulted in reperfusion of the distal coronary artery. Left ventricular (LV) performance was assessed before coronary angiography and at discharge from the hospital by use of gated cardiac blood pool imaging techniques. In patients evidencing reperfusion of the infarct-related coronary artery, mean (+/- SD) left ventricular ejection fraction (LVEF) increased from admission through discharge (46% +/- 15% to 55% +/- 10%, p = 0.002). In contrast, LVEF did not change from admission through discharge in patients with severe proximal stenoses alone or in patients with total occlusion who did not demonstrate reperfusion following SK administration (47% +/- 17% vs 49% +/- 18%, p = ns). In an additional 14 control patients with AMI who were not evaluated with coronary angiography, LVEF did not change from admission through discharge (46% +/- 12% vs 48% +/- 14%, p = ns). Quantitative thallium-201 perfusion imaging demonstrated an increase (p less than 0.05) in thallium uptake in the infarct segment following coronary artery reperfusion. In contrast, thallium uptake did not change (p = ns) in the infarct segment in patients not evidencing angiographic coronary artery reperfusion. These data support the following : (1) Coronary artery thrombus occurs frequently in AMI and can be lysed by IC SK, and (2) reperfusion with IC SK in patients with evolving myocardial infarction results in myocardial salvage and improved LV performance through hospital discharge.

A new, simplified and accurate method for determining ejection fraction with two-dimensional echocardiography.

A new method to determine left ventricular (LV) ejection fraction (EF) with wide-angle, two-dimensional echocardiography (2-D echo) has been developed using the parasternal long-axis, apical four-chamber and apical long-axis views. End-diastolic and end-systolic measurements of LV short axes at the base and mid-LV cavity in the parasternal long-axis view and at the upper, middle and lower thirds of the cavity in the apical views are made, from which an averaged minor axis at end-diastolic and at end-systole is calculated. Fractional shortening of the LV long axis (delta L) is estimated from apical contraction. Satisfactory 2-D echoes were obtained in 55 of 58 nonselected patients (all three views in 32 patients, two views in 22 and one view in one); 42 of 55 patients had coronary artery disease. EF by 2-D echo was compared with EF by gated cardiac blood pool imaging in all patients (r = 0.927, SEE = 6.7%) and to EF by single-plane cineangiography (angio) in 35 of 55 patients (r = 0.913, SEE = 7.4%). LV dyssynergy was frequently present and involved the apex in 29 of 55 patients. Using angio as the standard for evaluating wall motion at the apex, 2-D echo was 100% sensitive and specific in detecting abnormal apical wall motion. We conclude that EF can be determined accurately with 2-D echo in a large group of patients with and without dyssynergy by a simple method that eliminates the need for planimetry or computer assistance.

Intracoronary infusion of streptokinase in patients with acute myocardial infarction: effects of reperfusion on left ventricular performance.

Cardiac catheterization and coronary angiography were performed on hospital admission in 32 consecutive patients with acute myocardial infarction. Twenty-six patients had total occlusion of an infarct-related coronary artery and six had severe proximal stenosis with poor distal flow. In 18 of the 26 patients with total occlusion, intracoronary infusion of streptokinase resulted in reperfusion of the distal coronary artery. Seventeen of these 18 patients had severe coronary arterial stenosis at the site of the previous total occlusion. Hemodynamic indexes of left ventricular performance and ejection fraction determined by gated cardiac blood pool imaging did not change immediately after reperfusion (p [probability] = not significant [NS]). The mean (+/- standard deviation) left ventricular ejection fraction increased significantly (p = 0.007) from admission (44 +/- 15 percent) to hospital discharge (55 +/- 7 percent) in patients evidencing reperfusion of the occluded coronary artery. It did not change (p = NS) in this time span in the patients with severe stenosis alone, in those with total occlusion not demonstrating reperfusion after administration of streptokinase or in an additional 10 control patients with acute myocardial infarction not evaluated with coronary angiography. These data suggest that (1) coronary arterial thrombus is frequent in acute myocardial infarction and can be lysed by intracoronary streptokinase; (2) reperfusion with intracoronary streptokinase in acute myocardial infarction results in improved left ventricular performance between admission and hospital discharge.

Left ventricular diastolic performance at rest and during exercise in patients with coronary artery disease. Assessment with first-pass radionuclide angiography.

We used first-pass radionuclide angiocardiography to assess filling fraction during the first third of diastole, peak filling rate and peak filling rate during the first third of diastole as indexes of left ventricular diastolic performance at rest and after upright bicycle exercise in 32 normal patients and 68 patients with coronary artery disease. The mean filling fraction was unchanged from rest to exercise in normal patients (47+/- 15% vs 46 +/- 13%; NS). Even in 49 coronary patients with normal (greater than or equal to 50%) ejection fraction at rest, filling fraction was less than that in normal patients at rest (35 +/- 11% vs 47 +/- 15%, p less than 0.001). Despite similar resting heart rates, patients with coronary disease had lower (p less than 0.001) peak filling rate and peak filling rate during the first third of diastole than normal patients. With exercise, filling fraction decreased (p less than 0.001) from the resting value in coronary patients. These data suggest that (1) indexes of diastolic performance can be noninvasively assessed at rest and during exercise using first-pass radionuclide angiocardiography, (2) abnormalities in early diastolic performance are often present at rest in patients with coronary artery disease despite normal systolic performance, and (3) exercise-induced ischemia results in increased early diastolic dysfunction in patients with coronary disease.

Sequential postoperative assessment of left ventricular performance with gated cardiac blood pool imaging following aortocoronary bypass surgery.

The comparative effects of normothermic intermittent ischemic arrest (IIA) and cardioplegia (C) on left ventricular (LV) performance were assessed by gated cardiac blood pool imaging in 57 patients undergoing aortocoronary bypass surgery. In 34 patients, IIA was employed; 23 patients received C. Patients were studied preoperatively, sequentially in the immediate postoperative period at 30-minute intervals, and at 1 week after the operation, C and IIA groups did not differ in mean (+/- SEM) age, anginal class, number of diseased vessels, previous myocardial infarction, or preoperative ejection fraction (EF)(50 +/- 3% vs 50 +/- 2% [p = ns]). Aortic cross clamp time was greater with C than IIA (50 +/- 5 minutes vs 28 +/- 3 minutes [p = 0.001]). During the six sequential postoperative studies, transient LV dysfunction (greater than or equal to 7% decrease in absolute EF) was observed in 10 patients receiving C and in 16 patients receiving IIA. By time of discharge, 24 of 26 patients had returned to preoperative EF. Mean EF at discharge in the cardioplegia group did not differ compared to preoperative EF; in the IIA group, EF increased compared to preoperative EF (50 +/- 2% vs 55 +/- 2% [p < 0.01]). These data suggest that in patients with normal preoperative LV performance both C and IIA afford satisfactory myocardial preservation during aortocoronary bypass surgery.

First pass radionuclide assessment of right and left ventricular ejection fraction in chronic pulmonary disease. Effect of oxygen upon exercise response.

Right and left ventricular ejection fraction (RVEF; LVEF) were determined in patients with severe chronic pulmonary disease (mean +/- SEM [FEV1 percent predicted 36 +/- 3%; PaO2: 64 +/- 3 mm Hg]), utilizing first pass radionuclide angiocardiography. RVEF and LVEF were measured at rest and again during upright bicycle exercise while patients breathed room air, and again during low flow oxygen (O2) administration. Mean RVEF was abnormal (less than 45%) at rest and did not increase with exercise while subjects breathed room air (44 +/- 2 percent vs 44 +/- 3 percent, P = ns), but improved significantly during exercise while patients breathed O2 (45 +/- 5 percent vs 51 +/- 3 percent, P less than .05). Breathing room air, RV exercise ejection fraction was abnormal (less than 5 percent increase in absolute RVEF) in 15 of 18 patients, but only 5 of 10 patients were abnormal during O2 administration. LVEF at rest was normal in all subjects. These data suggest: 1) RV exercise ejection fraction is abnormal in most patients with chronic pulmonary disease; 2) while low flow O2 does not alter RV performance at rest, it improves RV exercise ejection fraction in some patients.

Quantification of hyperaemia bordering ischaemic myocardium in experimental myocardial infarction.

To quantify and determine the time course of hyperaemia adjacent to acutely ischaemic myocardium, 19 dogs underwent open-chest coronary-artery occlusion and 4 had sham-occlusion. At 15 min (19 animals) and 45 min (9 animals) post-occlusion regional myocardial blood flow (RMBF) was measured by the radionuclide-labelled microsphere technique. The dogs were sacrificed after 24 hours, the hearts were excised, sectioned into four segments from apex to base, and stained with triphenyl tetrazolium chloride (TTC). Transmural samples were taken from necrotic areas, normal areas, and the zone bordering the infarct. Each sample was divided into an endocardial and epicardial layer. At 15 min post-occlusion RMBF in the border zone was 16% greater than in the normal myocardium (116+/-16 vs 100+/-12 cm3xmin(-1)x100g(-1);P<0.05). In addition, the ratio of endocardial to epicardial flow was lower in the border zone (0.87+/-0.05) compared with normal myocardium (1.01+/-0.02; P<0.05) indicating that the hyperaemia observed was predominantly epicardial. From 15 to 45 min hyperaemic endocardial flow tended to decline: 126 to 108 cm3xmin(-1)x100g(-1) (P<0.05). In four sham-occlusion dogs there were no differences (P>0.05) in RMBF between sites equivalent to those sampled in occluded animals. These studies document a hyperaemic border zone persisting at least 45 min post-occlusion. Hyperaemia appears to be more prominent and of longer duration in the epicardium than endocardium.

Radionuclide assessment of right and left ventricular exercise reserve after total correction of tetralogy of Fallot.

First pass radionuclide angiocardiography under conditions of rest and exercise was utilized to evaluate a group of 16 postoperative patients who had undergone total surgical correction of tetralogy of Fallot. Functional data were related to thallium-201 myocardial imaging at rest, a noninvasive means of detecting right ventricular hypertrophy. All 16 patients were asymptomatic and 15 demonstrated normal right ventricular ejection fraction (equal to or greater than 45 percent) at rest. However, 13 patients manifested abnormal right ventricular ejection fraction responses to exercise (normal response is an absolute increment in an ejection fraction of 5 or greater percent). For the entire group, right ventricular ejection fraction at rest was 55 +/- 2 percent, whereas at exercise it was 52 +/- 2 percent (p = not significant). In contrast, left ventricular ejection fraction responses were normal in all patients. Thallium-201 imaging revealed substantial right ventricular uptake consistent with residual right ventricular hypertrophy, which was quantifiable in all patients. Thus, abnormalities in right ventricular performance during exercise may be detected readily by this radionuclide approach in these postoperative patients despite their asymptomatic clinical status and generally normal right ventricular performance at rest.

Multiple gated cardiac blood pool imaging for left ventricular ejection fraction: validation of the technique and assessment of variability.

The intrinsic variability and accuracy of left ventricular ejection fraction determined by multiple gated cardiac blood pool imaging was evaluated in 83 patients. Ejection fraction by gated studies correlated well with data from first pass radionuclide angiocardiography (r = 0.94) and from contrast angiography (r = 0.84). Intra- and interobserver variabilities of absolute ejection fraction were minimal (mean +/- standard deviation 1.4 +/- 1.2 and 1.6 +/- 1.5 percent, respectively) and were not different for normal (ejection fraction 55 percent or greater) and abnormal patients. Ejection fraction was determined twice in 70 patients: on the same day at intervals separated by 1 to 2 hours (41 patients) and on 2 different days (29 patients). Ejection fraction ranged from 18 to 91 percent and was normal in 37 patients. There was no difference in mean serial variabilities of absolute ejection fraction for all repeat studies performed on the same and separate days (3.3 +/- 3.1 versus 4.3 +/- 3.1 percent (not significantly different). The mean variability of absolute ejection fraction for repeat studies in normal patients was significantly greater than in abnormal patients (5.4 +/- 4.4 versus 2.1 +/- 2.0 percent, P less than 0.01). The incidence rate of absolute interstudy changes of 5 percent or more was significantly higher in normal than in abnormal patients (P less than 0.01). This differential variability should be considered in interpreting sequential changes in left ventricular ejection fraction. To be attributed to nonrandom physiologic alterations, the absolute change in ejection fraction should be 10 percent or more in normal patients and 5 percent or more in abnormal patients.

Serial assessment of doxorubicin cardiotoxicity with quantitative radionuclide angiocardiography.

We measured cardiac performance sequentially, using quantitative radionuclide angiocardiography to estimate left ventricular ejection fraction in 55 patients receiving doxorubicin for treatment of cancer. With final doxorubicin dosages greater than 350 mg per square meter, the lowest ejection fraction measured was significantly less than the initial determination. Five patients had severe cardiotoxicity (congestive heart failure). All had an ejection fraction of less than 30 per cent at the time of heart failure, and demonstrated moderate cardiotoxicity (a decline in ejection fraction by at least 15 per cent to a final value of less than 45 per cent) before clinical manifestations. Six patients with moderate toxicity in whom doxorubicin was discontinued did not have heart failure or a further decline in ejection fraction during the follow-up period. Moderate toxicity was continued, but mild toxicity (decline of ejection fraction by greater than 10 per cent, noted in 11 patients) was not well predicted. The assessment of radionuclide left ventricular ejection fraction during doxorubicin therapy may make it possible to avoid congestive heart failure.

Radionuclide assessment of ventricular performance during propranolol withdrawal prior to aortocoronary bypass surgery.

The effects of oral propranolol upon left ventricular performance were assessed in 18 patients with angiographically documented coronary artery disease in whom propranolol was tapered prior to elective aortocoronary bypass surgery. Left ventricular ejection fraction, ejection rate, and regional wall motion were obtained on three occasions with first-pass radionuclide angiocardiographic techniques. Patients were studied at peak propranolol dose ( +/- SEM) 224 +/- 29 mg./day; serum propranolol level, 85 +/- 22 ng./ml.), intermediate dose (99 +/- 9 mg./day; serum propranolol, 30 +/- 6 ng./ml.), and 24 hours following discontinuation of propranolol therapy. Heart rate increased significantly (62 +/- 2.3 vs 67 +/- 3.0 vs 73 +/- 2.3 beats/minute, p less than 0.001) during propranolol withdrawal, while systolic blood pressure did not change significantly (114.7 +/- 4.3 vs 110.3 +/-3.0 vs 113 +/- 3.0 mm. Hg, p greater than 0.05). There was no significant change in ejection fraction (59.1 +/- 2.4 vs 60.4 +/- 2.0 vs 59.2 +/- 2.5 per cent) or ejection rate 2.80 +/- 0.18 vs 2.87 +/- 0.18 vs 2.92 +/- 0.20 sec.-1) as propranolol was tapered (p greater than 0.05). No patient demonstrated a change in regional wall motion in response to propranolol withdrawal. The results of this study suggest that oral propranolol in commonly used clinical dosages does not significantly affect radionuclide measures of left ventricular performance in the basal state.