Predictors of left ventricular function after acute myocardial infarction: effects of time to treatment, patency, and body mass index: the GUSTO-I angiographic experience.

BACKGROUND: Despite the significant survival benefit associated with successful reperfusion therapy for acute myocardial infarction, global indices of outcome left ventricular function, such as ejection fraction, have often demonstrated little or no improvement. Although these measurements are confounded by numerous clinical, physiologic, and angiographic variables, no comprehensive analysis of this issue in a large series of patients is available. We used the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) database to better understand this phenomenon by determining independent predictors of left ventricular function and their interplay with regard to outcome ventricular function and improvement in function during the initial postinfarction week. METHODS: Ninety-minute and 5- to 7-day posttreatment global and regional indices derived from left ventriculograms were analyzed from a population of 676 patients. These observations were combined with clinical data to describe independent determinants of ventricular function outcome. RESULTS: Clinical factors predictive of global and regional ventricular function as well as improvement in function between 90 minutes and 5 to 7 days included time to treatment, early infarct-related artery flow grade, and body mass index. These same factors contribute significantly to compensatory hyperkinesis of the noninfarct zone, which is critical to maintenance of global ventricular function during this time period. CONCLUSIONS: The ventricular function benefits of early complete reperfusion after myocardial infarction are readily demonstrable after adjustment for multiple covariables and include (1) maintenance of global ventricular function and (2) prevention or delay in ventricular dilatation.

Relationship of infarct artery patency and left ventricular ejection fraction to health-related quality of life after myocardial infarction: the GUSTO-I Angiographic Study experience.

BACKGROUND: Post-myocardial infarction global ejection fraction and infarct-related artery patency might be expected to be associated with health-related quality-of-life (HRQOL) outcomes, but this association has not been previously shown. The GUSTO-I Angiographic Study cohort 2-year follow-up afforded an examination of such potential relationships. METHODS AND RESULTS: A total of 1848 patients (87.7% response rate) who were enrolled in the GUSTO-I Angiographic Study were contacted for a telephone interview regarding their current HRQOL (physical function, psychological well-being, perceived health status, and social function) 2 years after MI. In multivariable models, left ventricular ejection fraction (EF) was significantly related to physical (P:=0.021) and social (P:=0.014) function, psychological well-being (P:=0.042), and perceived health status (P:=0.024). Infarct-related artery patency was not directly related to any HRQOL outcome. A decreasing EF was predictive of poorer outcomes in each HRQOL dimension. Men consistently had better outcomes in all HRQOL dimension with the exception of perceived health status. Increasing age was predictive of poorer outcomes in all dimensions of HRQOL except for psychological well-being where the inverse occurred; younger patients experienced greater depression, anxiety and worry than their older counterparts. The presence of comorbidities increased the likelihood of worse outcomes in all dimensions. CONCLUSIONS: This is the first study to demonstrate a significant relationship between EF and long-term HRQOL outcomes. This advantage in left ventricular function preservation should be added to the mortality advantage when considering the impact of treatment strategies for myocardial infarction.

Low-molecular-weight heparins in acute myocardial infarction: rationale and results of a pilot study.

BACKGROUND: Antithrombotic adjuncts to fibrinolytic drugs for acute myocardial infarction increase the rate and speed of infarct artery recanalization. HYPOTHESIS: A low-molecular-weight heparin might be preferable to unfractionated heparin for this indication, as it has been shown to be in several other thrombus-related vascular disorders. METHODS: We performed a pilot study in 20 patients, all receiving aspirin and recombinant tissue plasminogen activator. Randomization was to standard dose intravenous unfractionated heparin or enoxaparin (the first dose given intravenously and followed by a subcutaneous administration). The endpoint was stability of anticoagulant effect. RESULTS: Enoxaparin produced stable therapeutic anti-Xa levels with minimal effect on activated partial thromboplastin times. Unfractionated heparin produced wide swings of these parameters, often outside desired levels. CONCLUSIONS: Enoxaparin may be a better antithrombotic agent than conventional unfractionated heparin when used in conjunction with fibrinolytics.

A randomized trial comparing primary angioplasty with a strategy of short-acting thrombolysis and immediate planned rescue angioplasty in acute myocardial infarction: the PACT trial. PACT investigators. Plasminogen-activator Angioplasty Compatibility Trial.

OBJECTIVES: The study evaluated the efficacy and safety of a short-acting reduced-dose fibrinolytic regimen to promote early infarct-related artery (IRA) patency during the inherent delay experienced by infarct patients referred for angioplasty as the principal recanalization modality. BACKGROUND: Previous approaches using long-acting, full-dose thrombolytic infusions rarely showed benefit, but they did increase adverse event rates. METHODS: Following aspirin and heparin, 606 patients were randomized to a 50-mg bolus of recombinant tissue-type plasminogen activator (rt-PA) (alpha half-life 4.5 min) or to placebo followed by immediate angiography with angioplasty if needed. The end points included patency rates on catheterization laboratory (cath lab) arrival, technical results when PTCA (percutaneous transluminal coronary angioplasty) was performed, complication rates, and left ventricular (LV) function by treatment assignment and time to restored patency following angioplasty. RESULTS: Patency on cath lab arrival was 61% with rt-PA (28% Thrombolysis in Myocardial Infarction trial [TIMI]-2, 33% TIMI-3), and 34% with placebo (19% TIMI-2, 15% TIMI-3) (p = 0.001). Rescue and primary PTCA restored TIMI-3 in closed arteries equally (77%, 79%). No differences were observed in stroke or major bleeding. Left ventricular function was similar in both treatment groups, but convalescent ejection fraction (EF) was highest with a patent IRA (TIMI-3) on cath lab arrival (62.4%) or when produced by angioplasty within an hour of bolus (62.5%). However, in 88% of angioplasties, the delay exceeded 1 h: convalescent EF 57.3%. CONCLUSIONS: Tailored thrombolytic regimens compatible with subsequent interventions lead to more frequent early recanalization (before cath arrival), which facilitates greater LV function preservation with no augmentation of adverse events.

Clinical predictors of early infarct-related artery patency following thrombolytic therapy: importance of body weight, smoking history, infarct-related artery and choice of thrombolytic regimen: the GUSTO-I experience. Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries.

OBJECTIVES: The purpose of this study was to determine patient characteristics that are a priori predictors of early infarct related artery patency following thrombolytic therapy, and to provide a paradigm which may identify patients who would be most likely to achieve restoration of normal (TIMI 3) coronary flow in response to thrombolytic therapy. BACKGROUND: Restoration of infarct-related artery perfusion in acute myocardial infarction is necessary for preservation of ventricular function and mortality reduction. Clinical variables that are a priori predictors of early patency with currently available thrombolytic regimens have not been fully characterized. METHODS: The probability of early infarct-related artery patency (TIMI 3 flow) was determined by multivariable logistic regression. We determined a reduced (parsimonious) model for predicting early (90 min) infarct-related artery patency (TIMI grade 3) based on data from 1,030 patients in the GUSTO-I Angiographic study. RESULTS: Predictors of 90 min TIMI 3 flow are use of an accelerated t-PA regimen (vs. streptokinase containing regimens) (chi2=39.1; p < or = 0.0001), infarct related artery (RCA/Lcx vs. LAD) (chi2=12.7; p=0.0004), body weight (chi2=10.3; p=0.001) and history of smoking (chi2=7.4; p=0.007). Time from symptom onset to treatment was not significant (p=0.71). CONCLUSIONS: The efficacy of currently available thrombolytic regimens is chiefly dependent on choice of thrombolytic regimen, body weight, infarct-related coronary artery and smoking history. Clinical variables alone correctly predict a priori TIMI 3 flow in the infarct-related artery 64% of the time. Patients with body weights greater than 85 kg are at a significant disadvantage with regard to achieving successful thrombolysis compared to those with lesser body weights.

Rescue angioplasty after failed thrombolysis: technical and clinical outcomes in a large thrombolysis trial. GUSTO-1 Angiographic Investigators. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries.

OBJECTIVES: We sought to assess the angiographic outcome, complication rates and clinical features of percutaneous transluminal coronary angioplasty (PTCA) after failed thrombolysis for acute myocardial infarction. BACKGROUND: "Rescue angioplasty" refers to mechanical reopening of an occluded infarct-related artery (IRA) after failed intravenous thrombolysis. Although the procedure is commonly performed, data describing its technical and clinical outcome are sparse. Early reports suggested that rescue PTCA is less often successful and produces more complications than primary PTCA. Other reports have described beneficial effects of successful rescue PTCA but adverse outcomes when PTCA is unsuccessful. METHODS: Using data from the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-1) angiographic substudy, we compared clinical and angiographic outcomes of 198 patients selected for a rescue PTCA attempt with those of 266 patients with failed thrombolysis but managed conservatively and, for reference, with those of 1,058 patients with successful thrombolysis. RESULTS: Patients offered rescue PTCA had more impaired left ventricular function than those in whom closed vessels were managed conservatively. Rescue successfully opened 88.4% of closed arteries, with 68% attaining Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow. The interventions did not increase catheterization laboratory or postprocedural complication rates. Multivariate analysis identified severe heart failure to be a determinant of a failed rescue attempt. Successful rescue PTCA resulted in superior left ventricular function and 30-day mortality outcomes, comparable to outcomes in patients with closed IRAs managed conservatively, but less favorable than in patients in whom thrombolytic therapy was initially successful. The mortality rate after a failed rescue attempt was 30.4%; however, five of the seven patients who died after failed rescue PTCA were in cardiogenic shock before the procedure. CONCLUSIONS: Rescue PTCA tends to be selected for patients with clinical predictors of a poor outcome. It is effective in restoring patency. Patients who die after a failed rescue attempt are often already in extremis before the angioplasty attempt.

Extended mortality benefit of early postinfarction reperfusion. GUSTO-I Angiographic Investigators. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries Trial.

BACKGROUND: Reperfusion therapy for myocardial infarction, understood to reduce mortality by preserving left ventricular function, was initially expected to provide increasing benefits over time. Surprisingly, large controlled thrombolysis trials demonstrated maximum benefit at 4 to 6 weeks with no subsequent increased treatment advantage. Such studies, however, compared groups by assigned treatment, not physiological effectiveness. METHODS AND RESULTS: We calculated 2-year survival differences among 2431 myocardial infarction patients according to early infarct artery patency and outcome left ventricular ejection fraction using Kaplan-Meier curves. Hazard ratios for significant survival determinants were derived from Cox regression models. Two-year vital status (minimum, 688 days) was determined in 2375 patients (97.7%). A substantial mortality advantage for early complete reperfusion (Thrombolysis in Myocardial Infarction [TIMI] grade 3) and for preserved ejection fraction occurred beyond 30 days. The unadjusted hazard ratio for the TIMI 3 group compared with lesser grades at 30 days was 0.57 (95% confidence interval [CI], 0.35 to 0.94) and 30 days to > or = 688 days was 0.39 (95% CI, 0.22 to 0.69). Consequently, early TIMI 3 flow was associated with approximately a 3 patient per 100 mortality reduction the first month with an additional 5 lives per 100 from 30 days to 2 years. For ejection fraction >40% compared with < or = 40%, the unadjusted hazard ratio was 0.25 (95% CI, 0.16 to 0.37) at 30 days and 0.22 (95% CI, 0.15 to 0.33) after 30 days through 2 years (lives saved, approximately 9 and 11 per 100, respectively). CONCLUSIONS: Successful reperfusion and myocardial salvage produce significant mortality benefits that are amplified beyond the initial 30 days.

End-systolic volume index at 90 to 180 minutes into reperfusion therapy for acute myocardial infarction is a strong predictor of early and late mortality. The Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO)-I Angiographic Investigators.

BACKGROUND: Left ventricular remodeling is an important sequela of myocardial infarction (MI). Although remodeling occurs soon after MI, the effect of early left ventricular dilatation on outcome is not established and may be useful for early risk stratification. We assessed whether end-systolic volume index (ESVI) at 90 to 180 minutes into thrombolytic therapy for MI is associated with adverse outcomes. METHODS AND RESULTS: In the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO)-I study, 41021 patients with evolving MI received one of four thrombolytic regimens. At 90 or 180 minutes into reperfusion therapy, 1300 patients underwent left ventriculography. ESVI was measured and correlated with adverse outcomes: 30-day and 1-year mortality and in-hospital congestive heart failure, shock, and reinfarction. Clinical variables were also tested in a stepwise logistic regression analysis to determine predictors of left ventricular dilatation. ESVI was directly related to all adverse outcomes with univariate analysis. ESVI of > or = 40 mL/m2 was independently associated with mortality (adjusted odds ratio [95% confidence interval]: 30-day, 3.4 [2.0 to 5.9]; 1-year, 4:1 [2.6 to 6.2], both P < .001). Male sex, prior angina or MI, weight of < 70 kg, heart rate of > or = 80 bpm, systolic blood pressure of < 110 mm.Hg, and anterior infarction were independent predictors of an ESVI of > or = 40 mL/m2. CONCLUSIONS: Left ventricular ESVI early into reperfusion therapy for MI strongly predicts adverse outcomes, including early and late mortality. The study establishes the role of very early left ventricular dilatation on outcome in MI and may be useful in identifying high-risk patients who might benefit from aggressive treatment, including the early use of ACE inhibitors.

Gender and acute myocardial infarction: is there a different response to thrombolysis?

OBJECTIVES: This study sought to 1) determine the effect of gender on early and late infarct-related artery patency and reocclusion after thrombolytic therapy for acute myocardial infarction; 2) examine the effect of gender on left ventricular function in response to injury/reperfusion; and 3) assess the independent contribution of gender to early (30-day) mortality after acute myocardial infarction. BACKGROUND: Women have a higher mortality rate than men after myocardial infarction. However, the effect of gender on infarct-related coronary artery patency and left ventricular response to injury/reperfusion have not been fully defined in the thrombolytic era. METHODS: Patency rates and global and regional left ventricular function were determined in patients at 90 min and 5 to 7 days after thrombolytic therapy for acute myocardial infarction. The effect of gender on infarct-related artery patency and left ventricular function was determined. Thirty-day mortality differences between women and men were compared. RESULTS: Women were significantly older and had more hypertension, diabetes, hypercholesterolemia, heart failure and shock. They were less likely to have had a previous myocardial infarction, history of smoking or previous bypass surgery. Ninety-minute patency rates (Thrombolysis in Myocardial Infarction [TIMI] flow grade 3) in women and men were 39% and 38%, respectively (p = 0.5). Reocclusion rates were 8.7% in women versus 5.1% in men (p = 0.14). Women had more recurrent ischemia than men (21.4% vs. 17.0%, respectively, p = 0.01). Ninety-minute ejection fraction and regional ventricular function were clinically similar in women and men with TIMI 2 or 3 flow (ejection fraction [mean +/- SD]: 63.4 +/- 6% vs. 59.4 +/- 0.7%, p = 0.02; number of chords: 21.4 +/- 0.9 vs. 21.0 +/- 1.9, p = 0.7; SD/chord: -2.4 +/- 08 vs. -2.4 +/- 0.2, p = 0.9, respectively). No clinically significant differences in left ventricular function were noted at 5- to 7-day follow-up. Women had a greater hyperkinetic response than men in the noninfarct zone (SD/chord: 2.4 +/- 0.2 vs. 1.7 +/- 0.1, p = 0.005). The 30-day mortality rate was 13.1% in women versus 4.8% in men (p < or = 0.0001). After adjustment for other clinical and angiographic variables, gender remained an independent determinant of 30-day mortality. CONCLUSIONS: Women do not differ significantly from men with regard to either early infarct-related artery patency rates or reocclusion after thrombolytic therapy or ventricular functional response to injury/reperfusion. Gender was an independent determinant of 30-day mortality after acute myocardial infarction.

Angiographic findings and outcome in diabetic patients treated with thrombolytic therapy for acute myocardial infarction: the GUSTO-I experience.

OBJECTIVES: This study sought to determine whether diabetes mellitus, in the setting of thrombolysis for acute myocardial infarction, affects 1) early infarct-related artery patency and reocclusion rates; and 2) global and regional ventricular function indexes. We also sought to assess whether angiographic or baseline clinical variables, or both, can account for the known excess mortality after myocardial infarction in the diabetic population. BACKGROUND: Mortality after acute myocardial infarction in patients with diabetes is approximately twice that of nondiabetic patients. It is uncertain whether this difference in mortality is due to a lower rate of successful thrombolysis, increased reocclusion after successful thrombolysis, greater ventricular injury or a more adverse angiographic or clinical profile in diabetic patients. METHODS: Patency rates and global and regional left ventricular function were determined in patients enrolled in the GUSTO-I Angiographic Trial. Thirty-day mortality differences between those with and without diabetes were compared. RESULTS: The diabetic cohort had a significantly higher proportion of female and elderly patients, and they were more often hypertensive, came to the hospital later and had more congestive heart failure and a higher number of previous myocardial infarctions and bypass surgery procedures. Ninety-minute patency (Thrombolysis in Myocardial Infarction [TIMI] flow grade 3) rates in patients with and without diabetes were 40.3% and 37.6%, respectively (p = 0.7). Reocclusion rates were 9.2% vs. 5.3% (p = 0.17). Ejection fraction at 90 min after thrombolysis was similar in diabetic and nondiabetic patients ([mean +/- SEM] 6.10 +/- 1.6% vs. 60.1 +/- 0.7%, p = 0.7), as was regional ventricular function (number of abnormal chords: 19.1 +/- 2.0 vs. 17.5 +/- 0.8, p = 0.3; SD/chord: -2.3 +/- 0.2 vs. -2.4 +/- 0.1, p = 0.6). Diabetic patients had less compensatory hyperkinesia in the noninfarct zone (SD/ chord: 1.3 +/- 0.2 vs. 1.7 +/- 0.1, p < or = 0.01). No significant difference in ventricular function was noted at 5- to 7-day follow-up. The 30-day mortality rate was 11.3% in diabetic versus 5.9% in nondiabetic patients (p < or = 0.0001). After adjustment for clinical and angiographic variables, diabetes remained an independent determinant of 30-day mortality (p = 0.02). CONCLUSIONS: Early (90-min) infarct-related artery patency as well as regional and global ventricular function do not differ between patients with and without diabetes after thrombolytic therapy, except for reduced compensatory hyperkinesia in the noninfarct zone among patients with diabetes. Diabetes remained an independent determinant of 30-day mortality after correction for clinical and angiographic variables.

Evolution of early TIMI 2 flow after thrombolysis for acute myocardial infarction. GUSTO-1 Angiographic Investigators.

BACKGROUND: Patients with early Thrombolysis in Myocardial Infarction (TIMI) grade 2 flow after thrombolysis appear to have outcomes similar to thrombolytic failures. To evaluate the origin and evolution of early TIMI 2 flow, we examined early and late angiographic and ventriculographic data from the Global Utilization of Streptokinase and TPA for Occluded Arteries (GUSTO-1) angiographic study. METHODS AND RESULTS: Of the 914 patients with both 90-minute and 5- to 7-day catheterizations, 278 patients had TIMI grade 2 flow at 90 minutes. At follow-up, 188 (67%) had improved to TIMI grade 3 flow. At 90 minutes, patients with TIMI grade 2 flow had greater infarct vessel narrowing and a significantly greater incidence of thrombus than patients with TIMI grade 3 flow. At the 5- to 7-day follow-up, patients whose flow had improved from TIMI grade 2 at 90 minutes to grade 3 flow at follow-up had larger-caliber vessels (minimum luminal diameter, 0.99 +/- 0.47 versus 0.84 +/- 0.48 mm; P = .03) and a lower incidence of visible thrombus (26% versus 38%, P = .04) than those with persistent TIMI grade 2 flow. These patients also had a higher mean ejection fraction (57.5 +/- 14.1% versus 52.8 +/- 12.9%, P = .02) and better infarct zone wall motion (-2.1 +/- 1.5 versus -2.6 +/- 1.3 SD per chord, P = .01) at the 5- to 7-day follow-up. Patients in whom flow improved from TIMI grade 2 at 90 minutes to TIMI grade 3 by 5 to 7 days had significantly better left ventricular function than patients with persistent TIMI grade 0, 1, or 2 flow and constituted a group whose left ventricular function was intermediate between those who had no reperfusion (TIMI grades 0 and 1) and those whose reperfusion was complete (TIMI grade 3). CONCLUSIONS: These data suggest that incomplete clot lysis plays a significant role in the pathogenesis of TIMI grade 2 flow. Furthermore, early TIMI grade 2 flow may be sufficient to provide prolonged myocyte viability, which will further recover if flow normalizes.

Increased left ventricular dysfunction in elderly patients despite successful thrombolysis: the GUSTO-I angiographic experience.

OBJECTIVE: This study sought to determine whether the recovery of regional and global left ventricular function is reduced in elderly patients despite successful thrombolytic therapy for acute myocardial infarction. Comparisons were made between elderly (> or = 75 years old, n = 47) and adult (< 75 years old, n = 434) patients enrolled in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO) angiographic trial who underwent catheterization at 90 min and 5 to 7 days after thrombolysis and who had an open infarct-related artery with Thrombolysis in Myocardial Infarction (TIMI) grade 2 to 3 flow at both times. BACKGROUND: The morbidity and mortality of acute myocardial infarction is increased in elderly patients, presumably because of multiple adverse coexistent baseline variables. However, functional recovery after thrombolysis has not been characterized in the elderly. METHODS: Ejection fraction, end-systolic volume index, infarct and noninfarct zone contractile function (SD/chord) and infarct extent (number of chords) were determined. RESULTS: At 90 min, elderly patients with an open infarct-related artery had decreased infarct zone contractile function (-2.8 +/- 0.2 vs. -2.3 +/- 0.1 SD/chord in adults, p < or = 0.05) and a greater extent of injury (26.0 +/- 2.6 vs. 20.7 +/- 0.8 chords in adults, p < or = 0.05). At 5- to 7-day follow-up ventriculography, ejection fraction was reduced, and end-systolic volume index was significantly increased in elderly patients compared with adults. The severity of regional wall motion dysfunction in the infarct zone was also greater in the elderly than in adults at 5- to 7-day follow-up (-2.6 +/- 0.2 vs. -1.9 +/- 0.1 SD/chord, respectively, p < or = 0.005). Non-infarct zone contractile function at 90-min ventriculography was similar in both groups. Despite a patent infarct-related artery at 90-min, the 30-day mortality rate in the elderly remained elevated (17.8%) compared with that of adults (4%) (p < or = 0.0001). Elderly patients were predominantly female and had a higher prevalence of hypertension, multivessel coronary disease, previous infarction, anterior infarctions and later time to treatment (between 3 and 6 h) than adults. However, age > or = 75 years remained an independent determinant by multivariable regression analysis of 1-week postinfarction end-systolic volume index, regional left ventricular dysfunction (p = 0.02 and p < or = 0.008, respectively) and 30-day mortality (p < or = 0.0001). CONCLUSIONS: Elderly patients had increased damage in the infarct zone and had persistently increased mortality despite sustained infarct-related artery patency after successful thrombolysis. Although the causes are probably multifactorial, a more rapid progression of ischemic injury or a blunted postreperfusion recovery appears to contribute to the poorer outcomes in elderly patients.

Doppler guide wire flow-velocity indexes measured distal to coronary stenoses associated with reversible thallium perfusion defects.

A Doppler guide wire was used to measure phasic coronary blood flow velocity distal to coronary stenoses in 17 symptomatic patients with corresponding positive exercise or adenosine thallium scintigrams. Distal average peak velocity and diastolic/systolic flow-velocity ratio were obtained in 16 vessels with stenoses (55% to 85% diameter stenosis) and a corresponding reversible thallium defect and in 11 control vessels with no stenosis or thallium defect. Coronary flow-velocity reserve was obtained with intracoronary adenosine. Coronary flow reserve (2.3 +/- 0.4 vs 1.2 +/- 0.3, p < 0.01) and diastolic/systolic flow-velocity ratio (1.95 +/- 0.56 vs 1.44 +/- 0.59, p < 0.04) were significantly different between normal vessels and distal to stenoses, respectively. Excellent concordance between distal coronary flow reserve and diastolic/systolic flow-velocity ratio to thallium scintigraphy was noted. A coronary flow reserve of < 1.8 and a diastolic/systolic flow-velocity ratio of < 1.7 predicted a reversible thallium perfusion scintigram (concordance 96% and 88%, respectively). Distal coronary flow velocity indexes may provide an alternative means of physiologic assessment of lesion severity during coronary angiography.

Early angiography cannot predict postthrombolytic coronary reocclusion: observations from the GUSTO angiographic study. Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries.

OBJECTIVES: The purpose of this study was to determine whether early qualitative or quantitative angiographic features can predict reocclusion after initially successful coronary thrombolysis. BACKGROUND: Although both the benefits of early reperfusion and the consequences of subsequent reocclusion after thrombolysis for acute myocardial infarction have been well described, efforts to describe angiographic markers of lesions at high risk for reocclusion have produced conflicting results. The Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO) angiographic trial provides the opportunity to examine these relations in the largest single, prospective patient cohort studied to date. METHODS: We studied 559 patients undergoing follow-up angiography at 90 min and 5 to 7 days after thrombolysis in the GUSTO trial. Patients received one of four thrombolytic regimens: 1) streptokinase with intravenous heparin; 2) streptokinase with subcutaneous heparin; 3) accelerated-dose recombinant tissue-type plasminogen activator (rt-PA) with intravenous heparin; or 4) a combination of streptokinase and conventionally dosed rt-PA with intravenous heparin. Qualitative variables examined at 90-min angiography included Thrombolysis in Myocardial Infarction (TIMI) flow grade, visible thrombus and lesion morphology. Quantitative variables included percent diameter stenosis, percent area stenosis, minimal lumen diameter and lesion length. The study contained a power > 0.85 to detect clinically important differences in percent diameter stenosis, percent area stenosis and minimal lumen diameter between the groups with subsequent reocclusion and sustained patency at the p = 0.05 level. RESULTS: At follow-up, 33 patients (5.9%) had reocclusion. The reocclusion rate for patients with early TIMI grade 2 flow was 6.3% versus 5.6% for TIMI grade 3 flow (p = NS). When the group with reocclusion was compared with the group with continued patency, there were no differences in presence of early visible thrombus, complex lesion morphology, percent diameter stenosis, percent area stenosis, minimal lumen diameter or lesion length. CONCLUSIONS: Our findings demonstrate that neither qualitative nor quantitative angiographic variables at 90 min after initiation of thrombolytic therapy can be used to predict subsequent coronary reocclusion.

Bedside monitoring of heparin therapy: comparison of activated clotting time to activated partial thromboplastin time.

Heparin anticoagulation is utilized during and after interventional cardiac catheterization procedures to reduce the risk of acute thrombotic coronary artery occlusion. The short half-life of heparin, the importance of maintaining therapeutic anticoagulation, and the time delay inherent in the processing and retrieval of the activated partial thromboplastin time (aPTT) by the hospital laboratory has generated interest in point-of-care heparin monitoring. The activated clotting time (ACT), the aPTT as assessed by both a new portable device, as well as the hospital laboratory, and heparin levels (H) were obtained from the same sample of blood in 100 patients receiving intravenous heparin. There was an excellent correlation between the aPTT determined at the bedside and by the hospital laboratory (r = .89). The ACT did not correlate well with either the laboratory or bedside aPTT (r = .63, .68 respectively). In the sub-therapeutic and therapeutic range, there was essentially no correlation between ACT and H. Only ACT values > 225 sec were predictive of therapeutic or supra-therapeutic aPTTs. ACT values < 225 sec, however, were not useful in predicting degree of anticoagulation. In situations in which the maintenance of therapeutic anticoagulation is critical as well as those in which the determination of lack of anticoagulation is required, the bedside determination of aPTT appears to be a useful tool.

Ventricular free wall and septal rupture (double rupture): a "pseudocomplication" during post-infarction laser angioplasty.

We report the rare occurrence of double rupture of the myocardium occurring immediately following successful laser recanalization of an occluded right coronary artery in a 72-year-old woman 5 days following infero-posterior myocardial infarction.

Peptide inhibition of myointimal proliferation by angiopeptin, a somatostatin analogue.

Vascular smooth muscle cell hyperplasia is a major component of atherogenesis in various animal models. Angiopeptin, a cyclic octapeptide analogue of somatostatin, markedly inhibits myointimal proliferation in response to endothelial cell injury in the rat carotid artery, rabbit aorta and iliac arteries and in coronary arteries of transplanted rabbit hearts. Angiopeptin does not affect serum lipid profiles in nonhuman primates. It is unlikely, therefore, that its antiproliferative effect is mediated by alterations in cholesterol metabolism. Angiopeptin and other peptide analogues of somatostatin are potent inhibitors of growth hormone release and insulin-like growth factor-1 production. However, inhibition of smooth muscle cell proliferation in vivo is not a property common to all somatostatin analogues. This suggests that plasma growth hormone and growth hormone-dependent insulin-like growth factor-1 production are not physiologic stimuli for myointimal proliferation in vivo. Angiopeptin inhibits 3H-thymidine incorporation into rat carotid artery explants, suggesting a local effect on autocrine or paracrine mechanisms regulating cell growth. In view of its potent inhibitory effect on smooth muscle cell replication, angiopeptin may have clinical utility in preventing restenosis after percutaneous transluminal coronary angioplasty and in preventing accelerated coronary atherosclerosis after cardiac transplantation.

Effect of cyclooxygenase inhibition on the pulmonary vasodilator response to furosemide.

Furosemide is a potent vasodilator of the systemic arterial and venous systems. The mechanism of vasodilatation, however, remains unclear. We investigated the vasodilatory effect of furosemide and its relation to endogenous prostaglandins (PGs). In the isolated canine lung lobe, furosemide significantly decreased mean pulmonary artery pressure. This effect was inhibited by indomethacin. Furosemide also attenuated the pulmonary vasoconstrictor response to the endoperoxide analog U46619 and PGF2 alpha. The pulmonary pressor response to a submaximal constrictor dose of arachidonic acid was significantly enhanced by furosemide, however, the pressor response to a maximal constrictor dose of arachidonic acid was attenuated, although not significantly. In animals pretreated with indomethacin, furosemide had no effect on the vascular response to PGF2 alpha, but the response to U46619 was significantly increased. Prostacyclin reduced pulmonary perfusion pressure and inhibited the pressor response to PGF2 alpha and U46619. Furosemide failed to alter inactivation of PGE2 on pulmonary lobe transit. We conclude that: 1) the vasodilatory activity of furosemide is mediated by increased production and not decreased metabolism of an endogenous cyclooxygenase product; 2) the effect of prostacyclin on vascular reactivity is similar to that of furosemide; and 3) local formation of prostacyclin by vascular tissue most likely mediates the vascular activity of furosemide.