P397 PROGNOSTIC VALUE OF CORONARY CALCIUM IN PATIENTS WITH COVID–19 AND SUSPECTED INTERSTITIAL PNEUMONIA: A CASE–CONTROL STUDY

Background

Short–term prognosis of SARS–CoV2 infection is mainly conditioned by the extent and severity of COVID–19 interstitial pneumonia. Coexistence of cardiac disease is however important and independently associated with an adverse outcome. Coronary calcium (CAC), detected at the time of chest computed tomography, can be a useful prognostic tool, as suggested by some cohort studies.

Material and Methods

We performed a retrospective, multi–centre, case–control (1:2) study in 195 COVID–19 patients admitted from 01–03–2020 to 30–04–2020. Cases were consecutive patients died within 30 days or admitted to the Intensive Care Units for invasive ventilation during the hospitalization (primary outcome measure). Controls were age– and sex–matched patients surviving until 30 days without need for invasive ventilation. For each case, we selected two controls, matched by age and sex dividing cases in age strata of 10 years, assuring within each age stratum twice the number of controls with an identical gender proportion. CAC estimation was performed with a with a semi–quantitative score (0 to 30) based on 10 segments and 4 degrees of severity of the calcification. Estimation of interstitial pneumonia, was similarly performed with a semi–quantitative score (from 0 to 20), based on 5 lobes and 5 degrees of severity of interstitial involvement. CT scans were acquired according to a standard protocol for non–cardio–synchronized chest CT, always on a multi–detector scanner with at least 16 layers.

Results

The mean CAC value in cases was significantly higher (p = 0.001) compared to controls: 5,52±1,38 vs 3,28±0,54 (mean value ± 95% CI). The percentage of cases with moderate–severe CAC was significantly higher (p = 0.013) compared to controls (41.5% vs 22.8%, OR 2.27 95% CI 1.20–4.29; primary end–point of the study). In multivariate analysis, independent predictors of outcome were (in descending order): interstitial pneumonia severity score (Wald 8.143, p = 0.004), CC score (Wald 5.569, p = 0.018), and the LDH value on admission (Wald 3.335, p = 0.034).

Conclusions

In our case–control study, the severity and extent of CAC is the main prognostic factor for the occurrence of adverse clinical outcome, beside the severity of interstitial pneumonia. These data suggest that a semi–quantitative estimation of CAC, feasible on any CT detector without the need of dedicated software, is clinically useful for the prognostic assessment of patients with COVID–19 interstitial pneumonia.

P58 IMMEDIATE CORONARY ANGIOGRAPHY AND SYSTEMATIC TARGETED TEMPERATURE MANAGEMENT ARE ASSOCIATED WITH IMPROVED OUTCOME IN COMATOSE SURVIVORS OF CARDIAC ARREST

Background

Rapid and systematic access to coronary angiography (CAG) and target temperature management (TTM) might improve outcome in comatose patients who survive cardiac arrest (CA). However, there is controversy around indicating immediate CAG in the absence of transmural ischemia on the electrocardiogram after return of spontaneous circulation (ROSC). We evaluated the short– and long–term outcome of our retrospective cohort of patients undergoing systematic CAG and TTM, based on whether culprit lesion percutaneous coronary intervention (PCI) was performed.

Methods

All consecutive comatose CA survivors with no obvious extracardiac causes undergoing TTM were included. Analysis involved the entire population and subgroups, namely patients with initial unshockable rhythm, no ST–elevation on electrocardiogram, and good neurological recovery.

Results

We enrolled 107 patients with a median age of 64.9 (57.7–73.6) years. The initial rhythm was shockable in 83 (77.6%). Sixty–six (61.7%) patients underwent PCI. In–hospital survival was 71%. It was 78.8% and 58.5% in those undergoing or not PCI (p = 0.022), respectively. Age, time from CA to ROSC and culprit lesion PCI were independent predictors of in–hospital survival. Long–term survival was significantly higher in patients who underwent PCI (respectively 61.5% vs 34.1%; Log–rank: p = 0.002). Revascularization was associated with better outcomes regardless of initial rhythm (shockable vs non–shockable) and ST–deviation (elevation vs no–elevation), and improved the long–term survival of patients discharged with good neurological recovery.

Conclusion

Systematic CAG and revascularization, when indicated, were associated with higher survival in comatose patients undergoing TTM, regardless of initial rhythm and ST–deviation in the post–ROSC electrocardiogram. The benefit was sustained at long–term particularly in those with neurological recovery.

Increased cardiac troponin I on admission predicts in-hospital mortality in acute pulmonary embolism

BACKGROUND

To investigate the frequency of cardiac troponin I (cTnI) increases in patients with pulmonary embolism (PE) and to assess the correlation between this finding, the clinical presentation, and outcomes.

METHODS

Consecutive patients admitted to the coronary care unit with acute PE were prospectively enrolled between January 2000 and December 2001. cTnI was sequentially determined. Various cut off concentrations were analysed, but patients were categorised prospectively as having increased or no increased cTnI based on a cut off concentration of 0.6 ng/ml. The main outcome measure was in-hospital mortality.

RESULTS

On admission, 14 of the 48 patients (29%) had cTnI concentrations greater than the receiver operating characteristic curve value used to diagnose acute myocardial infarction (> 0.6 ng/ml). Subsequently, six patients developed increases for an overall prevalence of 42% (20 of 42). The prevalence was higher when lower cut off concentrations were used: 73% (35 of 48) at the 99th centile and 60% (29 of 48) at the 10% coefficient of variability. Increased cTnI > 0.6 ng/ml was associated with a slower oxygen saturation (86 (7)% v 93 (4)%, p < 0.0001) and more frequent involvement of the main pulmonary arteries as assessed by spiral computed tomography (100% v 60%, p = 0.022). In-hospital mortality was 36% (5 of 14) of patients with increases > 0.6 ng/ml v 3% (1 of 42) of patients with lower concentrations (p = 0.008). Increased cTnI > 0.6 ng/ml on admission was the most powerful predictor of mortality (p = 0.046).

CONCLUSIONS

In high risk patients with acute PE, cTnI was frequently detected on admission. It was the strongest independent predictor of mortality.

Cardiac markers and risk stratification: an integrated approach

Risk stratification of patients with acute coronary syndromes (ACS) is pivotal for correct allocation of health resources and for maximizing the benefit of available treatment modalities. However, clinical and electrocardiographic indicators of high risk lack sufficient sensitivity for the detection of major cardiac events. The complementary information provided by the measurement of different biomarkers is believed to be very useful. Specifically, elevations of cardiac troponin I (cTnI) and T (cTnT) are strongly associated with a high-risk profile both at short- and long-term. This has been definitely demonstrated in many studies as well as in cumulative meta-analysis. The role of different biomarkers, such as those reflecting activation of hemostasis and the presence of inflammation, is however less defined. At the moment, no study has prospectively evaluated these biomarkers in the whole spectrum of unselected patients with ACS. It is also unclear whether these biomarkers add independent prognostic value to the clinical and electrocardiographic indicators of adverse outcome and whether they offer additional information when compared to each other. The Early Prognostic Value of Biochemical Markers of Myocardial Damage, Activation of Hemostatic Mechanism and Inflammation in Acute Ischemic Syndromes (EMAI) study has been prospectively designed to solve these issues. In this study, we have evaluated the prognostic value of cTnI and cTnT, D-dimer, prothrombin fragment 1+2 (F1+2), thrombin-antithrombin complex (TAT) and C-reactive protein (CRP) in patients with ACS at the time of admission. We have enrolled in 31 Italian Coronary Care Units 1971 patients with rest anginal pain within 12 h from admission and electrocardiographic evidence of myocardial ischemia. Of these, 730 patients resulted to have ST-segment elevation myocardial infarction eligible for a reperfusion strategy and 1241, an acute coronary syndrome without persisting ST-segment elevation. Primary outcome measure of the study is the composite of death and non-fatal MI within 30 days from admission, which has occurred in 8.9% of the study population.

Prognostic role of hemostatic markers in acute coronary syndromes patients

Coronary thrombosis is an important determinant of prognosis in patients with acute coronary syndromes (ACS). However, the identification of patients at high-risk for progression of coronary thrombosis is difficult in part because we currently lack clinically meaningful laboratory methods for its detection. The most promising approaches involve the measurement in plasma of markers of fibrin formation and degradation. Thrombin activity, as reflected by plasma or urine concentrations of fibrinopeptide A, is increased in patients with ACS and is associated with adverse outcome. However, the use of fibrinopeptide A as a marker of fibrin formation is limited by the very short half-life of the compound, by artifact due to sample acquisition, and by extremely long turnaround times. To overcome these limitations, measurement of soluble fibrin has been proposed. We have recently explored the prognostic value of a new fibrin-specific ELISA assay for soluble fibrin in patients with ACS and found that patients with highest levels had a twofold increased risk of early and late cardiac events. Increases in plasma concentrations of cross-linked fibrin degradation products (XL-FDPs), which reflect increased fibrin turn-over, are a marker of risk for complications of myocardial infarction. However, until recently, assays for XL-FDPs lacked specificity, because they did not distinguish between fibrin and fibrinogen degradation products. Recently, fibrin-specific ELISAs have been described and a rapid whole blood assay for D-dimer has been developed. We recently validated the prognostic value of this whole blood agglutination assay in patients with ACS. The results suggest that: (1) the detection of significant activation of the coagulation and/or fibrinolytic system may be important for rapid risk stratification of patients with ACS; (2) patients with biochemical evidence of ongoing coronary thrombosis may particularly benefit from aggressive antithrombotic strategies; (3) sequential measurements of these markers may be useful to guide antithrombotic treatment during the unstable phase of coronary artery disease.

[Low-molecular weight heparin and acute coronary syndrome: theoretical background and its use in clinical practice]

Thrombosis is responsible for the acute manifestations of coronary artery disease. Intravenous heparin has been shown to be effective in reducing the risk of death or myocardial infarction in patients with acute coronary syndromes. Compared to standard heparin, low-molecular weight heparins (LMWHs) have improved pharmacological and pharmacokinetic properties. A number of LMWHs, such as nadroparin, dalteparin and enoxaparin, have been evaluated in patients with acute coronary syndromes. FRISC (Fragmin during Instability in Coronary Artery Disease) and FRIC (Fragmin in Unstable Coronary Artery Disease), evaluated dalteparin and found the LMWH to be more effective than aspirin alone (FRISC) and as effective as heparin in a direct comparison (FRIC). In a small trial, nadroparin was shown to significantly reduce the risk of ischemic outcomes compared with a combination of aspirin and heparin, but this effect was no longer significant in the large FRAX.I.S. trial (FRAXiparine in Ischaemic Syndrome). Enoxaparin resulted in a statistically significant reduction in the combined outcome of death, myocardial infarction and recurrent angina or of urgent revascularization when compared with heparin in the ESSENCE (Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q-Wave Coronary Events) and TIMI 11B trials. Meta-analyzing of the data of these two trials revealed that even the combination of death and myocardial infarction was significantly reduced by the use of enoxaparin. There is accumulating evidence that LMWHs are safe and effective alternatives to standard heparin for the treatment of acute coronary syndromes and that they offer practical and therapeutic advantages.

Elevated cardiac troponin levels predict the risk of adverse outcome in patients with acute coronary syndromes

BACKGROUND

Elevations of cardiac troponin T or I are predictive of adverse outcomes in patients with acute coronary syndromes. However, odds ratios (ORs) vary substantially between studies. This investigation refines these values by means of a meta-analysis.

METHODS

Twenty-one studies were suitable. ORs were calculated for short-term (30 days) and long-term (5 months to 3 years) follow-up in patients with ST-segment elevation (ST upward arrow), in those without ST-segment elevation (no ST upward arrow), and in patients with unstable angina. The primary end point was a composite of death or nonfatal myocardial infarction.

RESULTS

A total of 18,982 patients were included. At 30 days, the OR for death or myocardial infarction was 3.44 (95% confidence interval [CI], 2.94-4.03; P <. 00001) for patients with positive troponin. In the ST upward arrow group, troponin elevations carried a 2.86-fold (95% CI, 2.35-3.47; P <.0001) higher risk during short-term follow-up, which was maintained long term. The no-ST upward arrow patients with troponin elevations manifested a 4.93-fold (95% CI, 3.77-6.45; P <.0001) increase of adverse outcomes. The OR for patients with unstable angina and positive troponin was 9.39 (95% CI, 6.46-13.67; P <.0001). For cardiac death alone, the results were similar.

CONCLUSIONS

Patients with acute coronary syndromes who have troponin elevations show a substantial increase in risk during short and long-term follow-up.

In vivo thrombin generation and activity during and after intravenous infusion of heparin or recombinant hirudin in patients with unstable angina pectoris

In patients with unstable angina, intravenous heparin reduces thrombin activity but does not influence thrombin generation. Recombinant hirudin, a direct thrombin inhibitor, may be more effective in inhibiting both thrombin generation and activity. We measured the plasma levels of prothrombin fragment 1+2 (a marker of thrombin generation) and fibrinopeptide A (a marker of thrombin activity) in 67 patients with unstable angina enrolled in the GUSTO (Global Use of Strategies to Open Occluded Coronary Arteries) IIb trial who were receiving either recombinant hirudin (31 patients) or heparin (36 patients). Blood samples were obtained at baseline (before any treatment), after 3 to 5 days of study drug infusion (immediately before discontinuation), and 1 month later. In the patients receiving recombinant hirudin, the prothrombin fragment 1+2 levels measured immediately before drug discontinuation were significantly lower than at baseline (P:=0.0014), whereas they had not changed in the patients receiving heparin; at this time point, the difference between patients receiving hirudin and those receiving heparin was statistically significant (P:=0.032). One month later, the prothrombin fragment 1+2 levels in both groups were similarly persistently high and did not differ from baseline. Fibrinopeptide A plasma levels at the end of infusion were significantly lower than at baseline in both treatment groups (P:=0. 0005 for hirudin and P:=0.042 for heparin) and remained lower after 1 month (P:=0.0001 for both hirudin and heparin). The fibrinopeptide A plasma levels were not different between patients treated with hirudin versus heparin at baseline, at the end of infusion, and after 1 month. Thus, in patients with unstable angina, in vivo thrombin generation and activity are reduced during intravenous infusion of recombinant hirudin. However, the inhibition of thrombin generation is not sustained, and after 1 month, the majority of patients have biochemical signs of increased thrombin generation.

[The role of biochemical markers of myocardial damage in clinical practice: the diagnosis of infarct and risk stratification. The Intersociety Interdisciplinary Study Group of the ANMCO-SIBioC-SIMeL, Markers of Muocardial Lesions. L'Associazione Nazionale Medici Cardiologi Ospedalieri-Società Italiana di Biochimica Clinica-Società Italiana di Medicina di Laboratorio]

For many years creatine kinase (CK) and CK-MB isoenzymes were used together with the ECG to confirm the presence of myocardial infarction. During the last decade newer cardiac markers have been introduced and immunological test systems developed for their quantification. Among these new markers, a prominent role has emerged for cardiac troponins (T or I). These technological advanced assays have shown greater sensitivity compared to "conventional cardiac enzymes;, thereby identifying patients with small--at times, microscopic--infarcts who would not have met defining criteria for myocardial infarction in an earlier era. Another major advantage shown by both cardiac troponins with respect to "conventional cardiac enzymes" is their ability to predict clinical outcome over a short- or long-term follow-up in patients with acute coronary syndromes, and this appears to be particularly relevant in patients with micronecrosis, who constitute a high-risk subgroup of unstable angina patients. Recently, myoglobin has also been widely applied as a marker. Although lacking in myocardial specificity, it is the earliest marker to show an increase after coronary occlusion. Thus, the combined use of myoglobin and a cardiospecific structural protein such as troponin T or I may prove an attractive strategy for biochemical testing in chest pain patients. With the routine use of these novel cardiac markers, fascinating opportunities are now open in the field of diagnostic classification (making the World Health Organization definition of myocardial infarction obsolete) and risk stratification in chest pain patients; opportunities that were unforeseen in the era of cardiac enzymes. However, the use of these markers has also posed some important questions on: a) the best and most cost-effective diagnostic strategy in chest pain patients; b) the remaining role of cardiac enzymes; c) the therapeutic consequences of a positive test result.

Soluble E-selectin is not a marker of unstable coronary plaque in serum of patients with ischemic heart disease

Increased level of soluble cell adhesion molecules may be a marker for atherosclerosis and/or reflect complication of the atherosclerotic plaque. To test whether expression of cell adhesion molecules is more pronounced in unstable versus stable coronary plaques, we measured the serum level of soluble E-selectin (sE-selectin) in 99 consecutive patients admitted to the hospital for acute coronary syndromes (ACS) and in 61 patients with chronic coronary artery disease (CAD) using a commercially available ELISA kit. We also measured the sE-selectin concentration in 20 sex- and age-matched subjects without clinical evidence of atherosclerosis, who served as controls. The mean sE-selectin level was higher in both groups of patients compared with controls (ACS, 35.0 +/- 23.4 ng/mL; chronic CAD, 32.9 +/- 21.0 ng/mL; controls, 14.5 +/- 6.6 ng/mL; one-way ANOVA, P = 0.001), but there was no difference between patients with ACS and chronic CAD. Furthermore, there was a trend (P = 0.08) toward a decrease in sE-selectin with an increase in the extent and severity of CAD. In patients with ACS, the in-hospital cardiac event rate was 8%. Although mean sE-selectin concentration tended to be higher in patients with (49.2 +/- 42.1 ng/mL) than in those without (33.8 +/- 21.3 ng/mL) in-hospital cardiac events, the difference was not significant. In 53 patients with ACS, C-reactive protein was measured and showed no correlation with the sE-selectin concentration. These findings show that although sE-selectin concentration is elevated in the presence of clinically relevant atherosclerosis, it does not further increase during the unstable phase of the disease, indicating that sE-selectin is not a reliable indicator of a complicated atherosclerotic plaque.

Prothrombotic genetic risk factors in young survivors of myocardial infarction

It has long been thought that an individual thrombotic tendency increases the risk of myocardial infarction, especially in young adults. Several "prothrombotic" genetic factors that may influence the individual thrombotic risk have been identified. To investigate the association between the risk of myocardial infarction at a young age and genetic factors thought to be associated with an increased tendency to thrombosis (the polymorphisms 4G/5G of the PAI-1 gene, PIA1/PIA2 of the platelet glycoprotein IIIa, C3550T of the platelet glycoprotein Ib gene, G10976A of the factor VII gene, C677T of the methylenetetrahydrofolate reductase gene, G1691A of the factor V gene, and G20210A of the prothrombin gene), we performed a case-control study evaluating 200 survivors (185 men, 15 women) of myocardial infarction who had experienced the event before the age of 45 years and 200 healthy subjects with a negative exercise test, individually matched for sex, age, and geographic origin with the cases. The presence of the PIA2 polymorphic allele was the only prothrombotic genetic factor associated with the risk of myocardial infarction at a young age. The odds ratio for carriers of the PIA2 allele compared with those of the PIA1 allele was 1.84 (95% confidence intervals (CI) 1.12 to 3.03). There was a significant interaction between the presence of the PIA2 allele and smoking: with their simultaneous presence, 46% (95% confidence intervals 11% to 81%) of premature myocardial infarctions were attributable to the interaction between the two factors. In conclusion, carrying the PIA2 polymorphic allele of platelet glycoprotein IIIa was the only genetic prothrombotic factor associated with the risk of developing myocardial infarction at a young age. The clinical expression of this genetic predisposition seems to be enhanced by smoking.

Early risk stratification of unstable angina/non-Q myocardial infarction: biochemical markers of coronary thrombosis

Coronary thrombosis is an important determinant of prognosis in patients with acute coronary syndromes (ACS). However, the identification of patients at high-risk for progression of coronary thrombosis is difficult partly because we currently lack clinically meaningful laboratory methods for its detection. The most promising approaches involve the measurement in plasma of markers of fibrin formation and degradation. Thrombin activity, as reflected by plasma or urine concentrations of fibrinopeptide A, is increased in patients with ACS and is associated with adverse outcome. However, the use of fibrinopeptide A as a marker of fibrin formation is limited by the very short half-life of the compound, by artifact due to sample acquisition, and by extremely long turnaround times. To overcome these limitations, measurement of soluble fibrin has been proposed. We have recently explored the prognostic value of a new fibrin-specific ELISA assay for soluble fibrin in patients with ACS and found that patients with the highest levels had a 2-fold increased risk of early and late cardiac events. Increases in plasma concentrations of cross-linked fibrin degradation products (XL-FDPs), which reflect increased fibrin turn-over, are a marker of risk for complications of myocardial infarction. However, until recently, assays for XL-FDPs lacked specificity, because they did not distinguish between fibrin and fibrinogen degradation products. Recently, fibrin-specific ELISAs have been described and a rapid whole blood assay for D-dimer has been developed. We recently validated the prognostic value of this whole blood agglutination assay in patients with ACS. These results suggest that: (1) The detection of significant activation of the coagulation and/or fibrinolytic system may be important for rapid risk stratification of patients with ACS; (2) patients with biochemical evidence of ongoing coronary thrombosis may particularly benefit from aggressive antithrombotic strategies; (3) sequential measurement of these markers may be useful to guide antithrombotic treatment during the unstable phase of coronary artery disease.

Clinical relevance of prodromal angina before acute myocardial infarction

The term preconditioning was applied to the observation made in 1986 by Murry and colleagues that canine myocardium subjected to brief episodes of ischemia and reperfusion would tolerate a more prolonged episode of ischemia better than myocardium not previously exposed to ischemia. Since that seminal observation, protective effect of preconditioning was demonstrated in all animal species tested, resulting in the strongest form of in vivo protection against myocardial injury other than early reperfusion. Angina heralding acute myocardial infarction may represent the clinical correlate of preconditioning phenomenon in humans. Data from small pathophysiological studies demonstrated that prodromal angina (<48 hours prior to index myocardial infarction) causes a reduction of infarct size and consequently a better left ventricular function compared with patients without such clinical feature before myocardial infarction. The protective effect of prodromal angina was also confirmed in larger prospective studies; its presence translates into a significant reduction of a combination of death, cardiogenic shock and pulmonary edema during hospital stay. The exact mechanism of such clinical phenomenon is however not known, but it may include preconditioning. Other mechanisms have been also claimed to play an important role, like a more rapid lysis of the occlusive thrombus within the infarct-related artery, or a rapid opening of intramural collateral not visible at angiography. Whatever the mechanism, it appears that patients with prodromal angina before myocardial infarction exhibit, when rapidly reperfused, a better post-infarction clinical outcome. At the present "optimal preconditioning-mimetic agents" are yet to be found, and "putting preconditioning in a bottle" still remains a pharmacologic challenge.

Direct comparison of early elevations of cardiac troponin T and I in patients with clinical unstable angina

BACKGROUND

The aim of this study was to compare the prognostic efficacy of cardiac troponin T (cTnT) and I (cTnI) in patients with clinical unstable angina.

METHODS

We studied 74 patients with chest pain at rest, electrocardiographic evidence of myocardial ischemia, and normal (<6.7 ng/mL) values of creatine kinase-MB. cTnT was measured with a commercial assay (cutoff level 0.1 ng/mL) and cTnI with a preliminary research application (cutoff level 3.1 ng/mL). All patients had blood drawn at baseline and 8 hours thereafter. The prospectively defined end point was the proportion of patients identified by each assay as having myocardial damage.

RESULTS

cTnT and cTnI were elevated in the same percentage of patients (18 of 74; 24%). Overall, 23 patients had elevations of 1 or both markers. In 13 there were elevations of both. Ten patients had elevations of only one (5 for each marker). In 51 patients, no elevations were present. Death or nonfatal myocardial infarction was more frequent in patients with elevated cTnI (27.7% vs 5.3%; P =.02) than those with normal values. The prognostic influence of cTnT was less (17% vs 8.5%; P =.2). However, the difference between the 2 markers when compared directly was not statistically significant (27.7% vs 17%; P = NS).

CONCLUSIONS

These data indicate that both markers identify myocardial damage in equal numbers of patients with clinical unstable angina. Patients with elevations had a worse short-term outcome. The significance of the minor differences in prognostic value will require additional studies.

[Platelet antiaggregants or anticoagulants in the secondary prevention after myocardial infarct]

Aspirin and oral anticoagulants are effective treatments in the secondary prevention after myocardial infarction. Aspirin at the dosage of 160-325 mg per day accomplishes a 21% reduction of the recurrences of vascular events (INR: 3-4). Oral anticoagulants are likely to be more effective; this therapy however is more demanding for the patient and the referring physician and is associated with a higher risk of hemorrhage. According to the available information from the literature, aspirin should be recommended for the majority of patients surviving after myocardial infarction. Oral anticoagulants should be reserved for post-infarction patients at high risk of thromboembolism and for those patients who present either intolerance to aspirin or recurrence of vascular events during aspirin treatment.

New markers for early diagnosis of acute myocardial infarction

The availability of 'new' biochemical markers of myocardial injury such as creatine kinase isoforms and troponins has renewed the interest for rapid confirmation/exclusion of myocardial infarction in patients presented to the hospital for suspected acute myocardial ischemia. Many of these protein markers have the potential to allow the diagnosis of acute myocardial infarction at a time from the onset of symptoms when the activity of creatine kinase MB is still within the reference range. However, the exclusion of classical myocardial infarction as defined by WHO criteria does not allow to conclude that the patient is at low-risk and can be safely sent home since he may have high-risk unstable angina. The sensitivity for the detection of myocardial damage of troponins is such that a substantial proportion of patients with unstable angina develop elevations of troponins in the absence of creatine kinase MB increases. It is now clear that such patients have an increased risk of cardiac events over the short and long-term similar to that of patients with definite myocardial infarction. Such finding may help in developing selective admission policies and deciding which patients deserve aggressive treatment.

Prognostic influence of elevated values of cardiac troponin I in patients with unstable angina

BACKGROUND

Elevations of the MB isoform of creatine kinase (CK) and cardiac troponin T seem to confer an adverse prognosis in unstable angina. We examined whether this prognostic influence is also present for cardiac troponin I (cTnI), a new and even more specific marker of myocardial injury.

METHODS AND RESULTS

We studied 106 patients with the clinical diagnosis of unstable angina showing chest discomfort at rest within 48 hours of admission, ECG evidence of myocardial ischemia, and normal values of total CK over the initial 16 hours of observation. The primary end point was death or nonfatal myocardial infarction (MI) at 30 days; the secondary end point was the incidence of cardiac events at 1 year. Blood was drawn every 8 hours for 3 days. Thirteen patients were excluded because of increased CK-MB mass concentrations within 16 hours of admission (non-Q-wave MI) and 2 because of inadequate blood sampling. Of the remaining 91 patients, 22 had cTnI elevations on admission (n=7) or after 8 hours (n=15). At 30 days, no deaths (0%) and 4 MIs (5.8%) occurred in the 69 patients with normal cTnI compared with 2 deaths (9.1%) and 4 MIs (18.2%) in the 22 patients with elevated cTnI. The combined incidence of death and nonfatal MI was 5.8% and 27.3%, respectively (P=.02). At 1 year, only 68% of patients with elevated cTnI were free of cardiac events, compared with 90% of those without elevations (P=.01).

CONCLUSIONS

These data indicate that cTnI is an important prognostic variable in patients with unstable angina. Elevations of cTnI predict an adverse short- and long-term prognosis.

The importance of antibody specificity in measuring cross-linked fibrin degradation products by ELISA

We and others have previously shown that plasma concentrations of XL-FDPs are accurately characterized with an enzyme-linked immunosorbent assay (ELISA) based on the monoclonal antibody DD-3B6/22, which is specific for D-dimer, and a pan-specific tag antibody (DD-4D2/182) in patients with thrombotic disorders. However, in patients treated with fibrinolytic agents, increases in non-cross-linked fibrin(ogen) degradation products are detected by the pan-specific tag antibody due to formation of complexes between non-cross-linked derivatives and XL-FDPs. Assays based on the use of fibrin degradation product-specific tag antibodies appear to be more specific, but whether they would be clinically more informative is unclear. Accordingly, in the current study we measured concentrations of XL-FDPs with two ELISAs; one based on the pan-specific tag antibody (DD-4D2/182) and another based on a fibrin degradation product-specific tag antibody (DD-1D2/48) in patients treated with three well-characterized thrombolytic regimens: one associated with minimal fibrinogenolysis (100 mg tissue-type plasminogen activator [t-PA]) over 3 h), moderate fibrinogenolysis (100 mg t-PA over 90 min), and one with marked fibrinogenolysis (1.5 MU streptokinase [SK]). In patients treated with t-PA, increases in XL-FDPs were closely correlated with fibrinogenolysis, as characterized by increases in the concentration of the Bbeta1-42 peptide, when measured with the pan-specific tag ELISA (r = 0.7), but not when measured with the fibrin degradation product-specific tag assay (r = 0.2). In patients treated with SK, concentrations of XL-FDPs were significantly higher (> 2000 ng/ml) with the pan-specific tag ELISA compared with the fibrin degradation product-specific tag ELISA (< 1000 ng/ml) 1, 2 and 8 h after start of the infusion (P < 0.01). Concentrations of XL-FDPs were also higher in patients treated with SK compared with t-PA when measured with the pan-specific tag ELISA, but lower with SK with the fibrin-specific ELISA (P < 0.01). The value of measurement of XL-FDPs in patients treated with fibrinolytic agents will need to be reappraised with the use of fibrin degradation product-specific assays, which appear to provide more accurate information on the kinetics of cross-linked fibrin lysis in patients treated with t-PA or SK.

Conjunctive administration of intravenous heparin attenuates cross-linked fibrin degradation in patients treated with streptokinase

Increases in thrombin activity occur in patients treated with streptokinase, but conjunctive therapy with intravenous heparin does not appear to improve either the rate of early infarct artery patency or survival in patients with acute myocardial infarction. In a recent study we found that concentrations of fibrinopeptide A, a marker of thrombin-mediated fibrin formation, were lower in the first 3 h in patients treated with intravenous heparin (5000 U bolus followed by a fixed-dose 1000 U/h infusion, n = 14) compared with subcutaneous (12,500 U every 12 h, started 4 h after streptokinse, n = 14) administration, but were increased in both groups of patients, consistent with persistent thrombin activity. To determine whether the differential effects of the intensity of heparinization on thrombin formation were reflected in differences in fibrin degradation, we measured cross-linked fibrin degradation products (XL-FDP) before and 1, 2, 3, 8, 12, and 24 h after streptokinase in the same cohort of patients, with a new ELISA with a D-dimer-specific capture antibody (MAb 3B6) and a fibrin-specific tag antibody (MAb 1D2, Agen, Brisbane, Australia). The incidence of early coronary recanalization assessed by creatine-kinase MM isoforms (increase in activity > or = 0.18%/min), was similar in both groups (79 vs 86%). Concentrations of XL-FDP were similar in patients with and without recanalization, but were lower in patients treated with intravenous compared with subcutaneous heparin at 8 h, but the results did not reach statistical significance (627 +/- 151 ng/ml versus 1007 +/- 157 ng/ ml, p = 0.06), and were significantly lower at 12 h (327 +/- 72 versus 781 +/- 162 ng/ml, p = 0.03 at 12 h) (mean +/- SEM). Concentrations of cross-linked fibrin degradation products were also lower in patients in whom the activated partial thromboplastin time was greater than two times the control, compared with those with inadequate anticoagulation (498 +/- 105 versus 1084 +/- 179 ng/ml; p = 0.02) (mean +/- SEM). Thus, more effective inhibition of thrombin with conjunctive intravenous heparin therapy results in less cross-linked fibrin turnover in the first 12 h after thrombolysis with streptokinase. This probably reflects decreased fibrin formation with therapeutic anticoagulation.

Non-invasive assessment of reperfusion of the infarct-related artery during coronary thrombolysis and its relation with left ventricular function

We monitored ST segment continuously for at least 3 h after the beginning of lytic treatment in 103 patients undergoing early coronary thrombolysis for acute myocardial infarction in order to ascertain whether this technique, which has been shown to be useful to assess recanalization of the infarct-related artery, is also able to identify the improvement in left ventricular function associated with successful reperfusion. Global left ventricular function (assessed in the 30 degrees right anterior oblique projection with the area/length method) and infarct zone wall motion (studied with the centerline method) were evaluated at least 4 weeks after the event. Reperfusion was thought to be achieved when ST segment elevation dropped > 50% relative to the most abnormal peak documented at any time in the study. Eighty patients (78%) met the criterium for successful reperfusion (group 1), and 23 (22%) did not (group 2). Both groups had similar clinical and angiographic characteristics. All indexes of global left ventricular function were significantly better in group 1 than in group 2 patients (end-diastolic volume: 176 +/- 51 vs. 209 +/- 76 ml, end-systolic volume: 66 +/- 40 vs. 97 +/- 55 ml, ejection fraction: 65 +/- 13 vs. 57 +/- 11%, respectively, all P < 0.02). Also the severity (-1.6 +/- 1.3 vs. -2.6 +/- 1.01 S.D./chord, respectively, P < 0.001) and the extension of hypokinesia in the infarct zone (number of chords with > 2 S.D.: 13 +/- 16 vs. 28 +/- 17, respectively, P < 0.0001) were less in group 1 than in group 2 patients. Furthermore, in reperfused patients, both global left ventricular function and regional wall motion were better in those admitted < 60 min from onset of pain. In conclusion, patients with rapid ( > 50%) decrease of ST segment elevation have smaller infarct size and better global left ventricular function than patients without electrocardiographic signs of reperfusion as assessed by continuous ST segment monitoring. This suggests that this non-invasive technique is a powerful tool able to identify patients most benefiting from thrombolytic therapy.

Prodromal angina limits infarct size. A role for ischemic preconditioning

BACKGROUND

In the experimental setting, it has been demonstrated that preconditioning myocardium before prolonged occlusion with brief ischemic episodes affords substantial protection to the cells by delaying lethal injury, thereby limiting infarct size. Whether the same occurs in humans remains unknown.

METHODS AND RESULTS

This study was undertaken to determine whether new-onset prodromal angina, defined as chest pain episodes limited to the 24 hours before myocardial infarction, is the clinical correlate of the ischemic preconditioning phenomenon. Twenty-five patients with their first anterior myocardial infarction treated with thrombolysis (recombinant tissue plasminogen activator [r-TPA], 100 mg/3 hours) were retrospectively included in the study because they met the following criteria: (1) < 120 minutes from onset of symptoms to reperfusion therapy, (2) < 90 minutes from the beginning of thrombolytic therapy to reperfusion (defined as rapid ST elevation reduction > 50%), (3) a patient infarct-related coronary artery with TIMI 3 flow and complete absence of collateral circulation to the infarct related artery (assessed at 24 +/- 5 days), and (4) the presence of new-onset prodromal angina, ie, typical chest pain episodes occurring at rest within 24 hours or, alternatively, a complete absence of symptoms before onset of infarction. Therefore, on the basis of their clinical status before infarction, the patients were divided into two groups: group 1, 13 patients without prodromal angina, and group 2, 12 patients with prodromal angina. Despite no difference in time to treatment (81 +/- 19 versus 75 +/- 21 minutes in group 1 and group 2, respectively; P = NS) and time to reperfusion (58 +/- 34 versus 46 +/- 24 minutes; P = NS), the peak of CKMB release was markedly lower in group 2 (86.3 +/- 66 versus 192.3 +/- 108.3 IU/L; P < .01). In addition, although both groups were comparable in terms of area at risk (amount of myocardium beyond the infarct-related stenosis; 15.1 +/- 4.6 versus 13.7 +/- 4.6 hypokinetic segments in group 1 and group 2, respectively, P = NS), the final infarct size (11 +/- 7.5 versus 5.6 +/- 4 hypokinetic segments, P < .04) was smaller in group 2. Thus, the limitation of the infarct size was significantly greater in group 2 (69% versus 36%; P < .05), and this represents an additional 33% reduction (95% confidence intervals, 7.1% to 58.9%; P = .01) in the group of patients with prodromal angina. Also, the third index, that is, the ECG, showed a favorable trend toward a lesser number of Q waves and a higher sigma R waves, although the values did not reach statistical significance.

CONCLUSIONS

Despite a similar area at risk, patients with new-onset prodromal angina showed a significantly smaller infarct size compared with patients without prodromal symptoms. Since the two groups had similar times to reperfusion and no evidence of collateral circulation to the infarct related artery, the protection afforded by angina in group 2 patients might be explained by the occurrence of ischemic preconditioning.

Failure of fixed dose intravenous heparin to suppress increases in thrombin activity after coronary thrombolysis with streptokinase

OBJECTIVES

This study was designed to define the extent of inhibition of thrombin activity achieved with conjunctive fixed dose intravenous sodium heparin compared with fixed dose subcutaneous calcium heparin in patients receiving intravenous streptokinase for acute myocardial infarction.

BACKGROUND

The role of heparin therapy during coronary thrombolysis with streptokinase is controversial, in part because the efficacy of different conjunctive heparin regimens in inhibiting early increases of thrombin activity is not known.

METHODS

Twenty-eight patients treated with 1.5 million U of streptokinase and 165 mg of aspirin for acute myocardial infarction were randomly assigned to receive fixed dose subcutaneous heparin therapy (12,500 U every 12 h delayed until 4 h after the end of streptokinase therapy [n = 14]) or fixed dose intravenous heparin (5,000-U bolus followed by 1,000-U/h infusion [n = 14]). Anticoagulation was assessed with serial measurements of activated partial thromboplastin time, and thrombin activity by measuring fibrinopeptide A and thrombin-antithrombin III complex levels. Plasma concentrations of creatine kinase (CK) MM isoforms were measured for 3 h to determine recanalization (increase in activity > 0.18%/min).

RESULTS

Recanalization occurred in 27%, 64% and 79% of patients given subcutaneous heparin versus 43%, 76% and 86% of those given intravenous heparin at 1, 2 and 3 h, respectively (p = 0.6). Concentrations of fibrinopeptide A (mean +/- SEM) at 1 h were higher in patients without (n = 5) than in those with (n = 23) CK-MM isoform criteria for recanalization (76.4 +/- 25.7 vs. 25.2 +/- 5.2 nmol/liter, p = 0.02), and at 1, 2 and 3 h were significantly lower with fixed dose intravenous heparin (18.4 +/- 4.8 vs. 46.7 +/- 10.2 nmol/liter at 1 h, p = 0.004) than without heparin. After fixed dose subcutaneous heparin at 4 h, fibrinopeptide A levels were similar in both groups despite lower activated partial thromboplastin times in patients who received fixed dose subcutaneous heparin. However, fibrinopeptide A was not consistently suppressed in either group (fixed dose subcutaneous heparin 8.7 +/- 1.8 nmol/liter vs. fixed dose intravenous heparin 11.8 +/- 5.2 nmol/liter) at 48 h (p = 0.4). No significant changes in the concentration of thrombin-antithrombin III complexes were found between the two groups.

CONCLUSIONS

Fixed dose intravenous heparin attenuates increases in fibrinopeptide A early after streptokinase. Subsequent fixed dose intravenous and subcutaneous heparin have similar effects but are relatively ineffective in suppressing thrombin activity, suggesting a role for more potent antithrombin agents during coronary thrombolysis with streptokinase.

Concurrent nitroglycerin therapy impairs tissue-type plasminogen activator-induced thrombolysis in patients with acute myocardial infarction

Nitroglycerin given with tissue-type plasminogen activator (t-PA) has been shown to decrease the thrombolytic effect of t-PA in animal models of coronary artery thrombosis. The present study was conducted to determine whether such an interaction between nitroglycerin and t-PA occurs in patients with acute myocardial infarction undergoing thrombolytic treatment. Patients with acute myocardial infarction were treated with t-PA plus saline solution (group 1; n = 11) or t-PA plus nitroglycerin (group 2; n = 36). Stable coronary artery reperfusion assessed by continuous ST-segment monitoring in 2 electrocardiographic leads, and release of creatine kinase occurred in 91% of group 1 patients and in 44% of group 2 patients (95% confidence interval, 14% to 82%; p < 0.02). Plasma levels of t-PA antigen were consistently (p < 0.005) higher in group 1 than in group 2 patients up to 6 hours after t-PA infusion. Conversely, plasminogen activator inhibitor-1 (PAI-1) levels were slightly higher in group 2 than in group 1 patients. These observations indicate that nitroglycerin given with t-PA significantly decreases the plasma t-PA antigen concentrations and impairs the thrombolytic effect of t-PA in patients with acute myocardial infarction.

[Echocardiographic study of left ventricular function using automated border detection in normal subjects]

BACKGROUND

Two-dimensional (2D) echocardiographic automated border detection (ABD) can provide on-line measurement of left ventricular cavity area and fractional area change. However, this new quantitative method has not been extensively validated.

METHODS

Values of manually traced areas on 2D-echo images were compared with those obtained from ABD in 34 consecutive normal subjects (age 16-65 years). Only subjects with more than 70% of endocardial border circumferences clearly seen in both selected imaging planes were included in the study. We evaluated left ventricular end-diastolic and end-systolic area, and fractional area change obtained from mid-left ventricular short axis and apical 4-chamber view. Left ventricular volumes (area/length method) and ejection fraction were manually calculated off-line from apical 4-chamber view.

RESULTS

From the short axis view, left ventricular cavity area measurements with ABD were obtained in 85% of subjects. The values closely correlated with off-line measurements: end-diastolic area 15.6 +/- 3.1 vs 14.8 +/- 3.3 cm2, r = 0.88 SEE = 1.58; end-systolic area 7.2 +/- 1.7 vs 6.7 +/- 1.7 cm2, r = 0.88 SEE = 0.80. A good correlation was also found for the apical 4-chamber view; end-diastolic area 25.9 +/- 5.9 vs 25.3 +/- 5.5 cm2, r = 0.97 SEE = 1.36; end-systolic area 16.3 +/- 4.1 vs 15.0 +/- 3.8 cm2, r = 0.92 SEE = 1.51. In this view ABD measurements were obtained in 79% of subjects. A significant correlation was also found between the end-diastolic volume and short axis (r = 0.54, SEE = 2.63; p 0.003) and apical 4-chamber (r = 0.66, SEE = 4.51; p = 0.0002) ABD diastolic area. Similarly, the end-systolic volume was significantly correlated with short axis (r = 0.57, SEE = 1.42; p = 0.001) and apical 4-chamber (r = 0.55, SEE = 3.54; p = 0.003) ABD systolic area. However, the on-line fractional area change correlated with off-line ejection fraction better from short axis view: (r = 0.72 SEE = 3.52) than from apical 4-chamber view (r = 0.45 SEE = 6.84).

CONCLUSIONS

These data indicate that: 1) left ventricular areas measured by ABD correlate well with manually measured areas and volumes; 2) short axis ABD fractional area change may be a reliable substitute of off-line manually traced ejection fraction in normal subjects.

Vasotonic angina: a spectrum of ischemic syndromes involving functional abnormalities of the epicardial and microvascular coronary circulation

OBJECTIVES

The present study was undertaken to investigate the response of large and small coronary arteries in a subgroup of patients with no or minimal coronary artery disease found to have objective signs of myocardial ischemia.

BACKGROUND

Many patients apparently have normal coronary arteries despite abnormal electrocardiographic (ECG) changes during spontaneous anginal attacks or exercise stress testing.

METHODS

Twenty-five patients with no or minimal (< 30% stenosis) coronary artery disease were chosen from a pool initially selected on the basis of spontaneous anginal attacks and ST segment shifts in the anterior leads. Of these, 10 were grouped as having variant angina (at least one episode of ST elevation) and the remaining 15 as having syndrome X (exercise-induced anginal pain, ST depression and reversible thallium abnormalities). Data were compared with those obtained in 10 patients with stable angina and documented coronary artery disease. Eighteen patients with supraventricular arrhythmias and normal coronary arteries served as control patients. Patients showing focal spasm during ergonovine testing were not included in the subsequent angiographic analysis. Great cardiac vein blood flow, aortic pressure and changes in coronary artery diameter were measured at rest and 2 to 4 min after hyperventilation in the remaining study group. The same procedure was repeated after sublingual administration of 0.3 mg of nitroglycerin in eight patients (four with syndrome X and four with variant angina).

RESULTS

Hyperventilation induced diffuse epicardial coronary diameter reduction, which was marginal in control patients (9 +/- 4%) and those with coronary artery disease (5 +/- 3%) but severe (p < 0.001) in those with variant angina (28 +/- 14%) or syndrome X (25 +/- 13%). Concomitant determination of coronary blood flow showed significant (p < 0.001) decreases in those with variant angina (25 +/- 11%) and syndrome X (28 +/- 10%) but not in control patients (5 +/- 8%) or those with coronary artery disease (4 +/- 5%). Changes in great cardiac vein blood flow during hyperventilation were similar before and after nitroglycerin.

CONCLUSIONS

These findings indicate that vasoconstrictor stimuli may trigger a diffuse abnormal response of both epicardial and resistance vessels in some patients with chest pain and angiographically normal coronary arteries. Patients showing such diffuse vasoconstrictor abnormalities are suggested to have a single pathogenetic entity with a spectrum of ECG manifestations ranging from ST depression to ST elevation.

Patency of the infarct-related artery and left ventricular function as the major determinants of survival after Q-wave acute myocardial infarction

One hundred seventy-two patients with 1-vessel disease documented at predischarge angiography who had been followed for 43 +/- 30 months after an initial Q-wave acute myocardial infarction were retrospectively evaluated to investigate the prognostic value of infarct-related artery patency and left ventricular (LV) function. Multiple logistic regression analysis revealed that only infarct artery patency (Thrombolysis in Myocardial Infarction [TIMI] grades 2-3 vs 0-1) (Z = 2.24; p < 0.05) and end-systolic volume index (Z = -2.67; p < 0.01) were independently related to survival. Sixteen cardiac deaths were observed; all 16 patients had LV dysfunction (defined as end-systolic volume index > 40 ml/m2), and 15 had an occluded infarct-related artery. In the subgroup with LV dysfunction, the 10-year percent survival rate was 20% among patients with TIMI grade 0 to 1 versus 96% with grade 2-3 (p < 0.001). Patency of the infarct-related artery was also the only independent predictor of recurrent ischemia (Z = 2.59; p < 0.01). In conclusion, both infarct-related artery patency and LV function are independent predictors of survival after Q-wave acute myocardial infarction. Patients with normal LV function have an excellent long-term prognosis, which is only partially counterbalanced by the tendency toward clinical instability observed in those with an open infarct-related vessel. However, when an occluded infarct-related artery is observed in the setting of LV dysfunction, the long-term outcome appears to be relatively poor.

[Regional coronary blood flow in patients with acute myocardial infarct treated by systemic fibrinolysis]

Thrombolysis has been reported to restore coronary blood flow in patients with acute myocardial infarction (AMI). However, the relationship between fibrinolytic treatment and evidence of myocardial reperfusion has not been adequately assessed. Accordingly, we measured great cardiac vein blood flow (GCVF:thermodilution) in 12 patients (Group 1) presenting with AMI (chest pain < 4 hours and ST elevation in the anterior leads) before and following i.v. urokinase (UK:2 million U/90 min). Ten patients receiving conventional treatment served as controls (Group 2). UK induced a significant increase of GCVF (from 101 +/- 24 to 164 +/- 42 ml/min, p < 0.001). Maximal increase occurred after 50 +/- 54 min from drug infusion. Conversely, changes in GCVF were not significant in Group 2 (from 103 +/- 35 to 106 +/- 31 ml/min, NS). Following 24 hours changes in GCVF were still consistent only in Group 1 patients. Individual analysis during 24 hours showed marked fluctuations of GCVF peak values in Group 1 patients (62 +/- 43%), but not in Group 2 (29 +/- 21%). Thus, UK induces a marked increase of GCVF in most patients with anterior AMI; such increase suggests that reperfusion occurs early (i.e. within 1 hour) from UK administration. Fluctuations of GCVF during monitoring are magnified by thrombolysis, suggesting intermittent coronary reocclusion in the early hours of AMI.

[The differentiated effects of fibrinolysis on the coronary flow in patients with unstable angina]

BACKGROUND

Intracoronary (i.c.) thrombus is a frequent finding in patients (pts) with unstable angina (UA). Accordingly, thrombolytic treatment could be beneficial, as resolution of thrombus might result in increased delivery of blood flow to the ischemic regions.

METHODS

To test this hypothesis we studied 13 pts with UA refractory to maximal medical treatment and ST segment shift in the anterior leads. Coronary angiography was performed and great cardiac vein blood flow (GCVF; thermodilution) was measured in all pts within 48 hours (mean 29 +/- 13 hrs) from the last chest pain episode. Following angiography, pts received i.v. wrokinase (UK: 1 million IU/30 min); aortic pressure and GCVF were measured before and every 10 min during drug infusion, for a total time of 90 min.

RESULTS

At baseline angiography 5/13 pts (Group 1) had evidence of i.c. thrombus (intraluminal filling defect or thrombotic subocclusion) in the ischemia-related left coronary artery, whereas 8 pts (Group 2) did not. Overall, coronary hemodynamics did not change significantly following drug administration: GCVF was 103 +/- 65 on baseline and 117 +/- 68 ml. min after UK; p > 0.05. Conversely, group analysis showed that UK increased GCVF and decreased anterior coronary resistances (mean aortic pressure/GCVF) in Group 1 (respectively from 86 +/- 33 to 114 +/- 41 ml. min: p < 0.005; and from 1.37 +/- 0.68 to 1.01 +/- 0.44 mmHg/ml. min: p < 0.05) but not in Group 2 (both: p > 0.05), despite similar effects on aortic pressure.

CONCLUSIONS

Fibrinolytic treatment can be of therapeutic value in UA; UK has shown to increase regional coronary blood flow in selected pts presenting with refractory angina as well as evidence of i.c. thrombus at early angiography. Heterogeneity of angiographic findings could explain controversies in trials dealing with thrombolysis in UA.

Transient ischaemia refractory to conventional medical treatment in unstable angina: angiographic correlates and prognostic implications

Complex stenosis morphology is frequently seen in patients with unstable angina. However, its relation to transient myocardial ischaemia and clinical outcome has not been adequately elucidated. We studied 86 patients admitted to the Coronary Care Unit for unstable angina; all patients underwent ECG Holter monitoring during the first 2-4 days, while receiving intensive triple drug treatment. Coronary angiography and subsequent analysis of the ischaemia-related artery were performed within 12 days of admission. Patients were grouped according to their angiographic features: 45 showed complex coronary morphology (CM: 29 eccentric stenosis with irregular borders or overhanging edges; 16 intracoronary thrombus), 11 had documented coronary spasm as well as moderate atherosclerosis (CS), seven had left main coronary artery disease, and the remaining 23 patients showed regular and smooth morphology of coronary stenosis (RM). At admission, transient myocardial ischaemia (TMI) was greater in patients with CM (85 +/- 60 min .24 h-1) than in those with RM or CS (33 +/- 26 min .24 h-1; P less than 0.005). After 3 days of full medical treatment TMI decreased in all groups, but 34/45 patients with CM and 9/34 with RM or CS still showed residual ischaemia (greater than 0 min .24 h-1): 76% vs 26%, P less than 0.02. Follow-up was obtained at hospital discharge and after 1 year in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary hemodynamic effects of systemic thrombolysis in patients with unstable angina

Intracoronary (i.c.) thrombus is a frequent finding in patients with unstable angina (UA). Accordingly, thrombolytic treatment could be beneficial, as resolution of thrombus might result in increased delivery of blood flow to the ischemic regions. To test this hypothesis, we studied 13 patients with active UA and ST-segment shift in the anterior leads. Coronary angiography was performed and great cardiac vein blood flow (GCVF; thermodilution) was measured in all patients 25 +/- 14 h after the last chest pain episode. Following angiography, patients received i.v. urokinase (UK: 1,000,000 IU/30 min); aortic pressure and GCVF were measured before and every 10 min following drug infusion, for a total time of 90 min. At baseline angiography, 5 of 13 patients (Group 1) had evidence of i.c. thrombus (intraluminal filling defect or thrombotic subocclusion) in the ischemia-related left coronary artery, whereas 8 patients (Group 2) did not. Group analysis showed that UK increased GCVF and decreased anterior coronary resistance in Group 1 (respectively, from 86 +/- 33 to 114 +/- 41 ml/min: p less than 0.005; and from 1.37 +/- 0.68 to 1.01 +/- 0.44 mmHg/ml/min: p less than 0.05) but not in Group 2 (both: p = NS). In conclusion, UK has been shown to increase regional coronary blood flow in selected patients presenting with active UA, as well as evidence of i.c. thrombus at early angiography. Heterogeneity of angiographic findings could explain controversies in trials dealing with thrombolysis in UA.

Angiographic morphology in unstable angina and its relation to transient myocardial ischemia and hospital outcome

Complex stenosis morphology frequently occurs in patients with unstable angina pectoris. However, its relation to transient myocardial ischemia and hospital outcome has not been ascertained. To address this issue, 88 patients with significant (greater than or equal to 50%) coronary artery disease presenting with angina--new onset (n = 38), worsening (n = 20) or at rest (n = 30)-were studied. Patients with left main artery disease, normal coronary arteries or occlusion of the ischemia-related arteries were not included in the study. Continuous electrocardiographic recordings were obtained during the first 24 hours. Angiography was performed within 1 week from admission. Complex morphology was defined as any stenosis with irregular borders, overhanging edges or intracoronary thrombus. Only data referring to the in-hospital outcome were considered in this study. Adverse end points were sudden death, myocardial infarction and emergency revascularization. Analysis of the angiograms revealed a complex morphology in 58 patients (group 1). The remaining 30 patients served as control subjects (group 2). Thirty-two of the 58 group 1 patients had an unfavorable clinical outcome (positive predictive value, 55%). A similar outcome occurred in only 2 of the 30 group 2 patients (negative predictive value, 93%). Of the 32 group 1 patients who had an unfavorable clinical outcome, 29 had a cumulative duration of transient myocardial ischemia of greater than or equal to 60 minutes per 24 hours. A similar duration of ischemia, however, was observed in another 6 group 1 and in 8 group 2 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Variant angina which interacts with two phenomena: local hypersensitivity and abnormal response in the coronary tree to vasoconstrictor stimuli]

The aim of the present study was to evaluate the vasomotion of the entire coronary tree in variant angina, particularly focusing the attention on the behaviour of the "non spastic" epicardial vessels, using a quantitative coronary technique. Two different groups of patients served as controls. The first group consisted of 10 patients with accessory nodal pathway but without any sign of myocardial ischemia (Group I). The second group included 8 patients with stable exertional angina pectoris and coronary artery disease (Group II). The third group (Group III) consisted of 16 patients presenting with variant angina and spontaneous or hyperventilation-induced (HV: 30 cycles/min for 5 min) ST segment elevation. All patients underwent coronary angiography before and 2 min after HV testing; the evaluation of the coronary diameters was performed on baseline and after HV. In Group III, the HV testing caused a 26 +/- 12% reduction of the "non spastic" coronary vessels, with the mean control diameter of 2.00 +/- 0.61 mm that decreased to 1.48 +/- 0.55 mm. The patients of Group I showed only a mild degree of vasoconstriction (9 +/- 6%) of the epicardial coronary vessels; the Group II patients, also, showed a moderate response to vasoactive stimulus (11 +/- 8%), with the mean control diameter of 2.36 +/- 0.69 mm that decreased to 2.09 +/- 0.65 mm. The greater amount of vasoconstriction showed by patients with variant angina was statistically significant compared to both control groups (p less than 0.001). A further analysis of the coronary vasomotion, in Group III patients, showed that the 6 patients with normal or near normal coronary angiograms exhibited a 34% reduction in the vessel diameter. The remaining 10 patients who presented with a diffuse atherosclerotic involvement of the epicardial vessels (organic stenosis greater than or equal to 50% at the site of spasm) showed a lesser (20%) but yet significant extent of vasoconstriction compared to both control groups (p less than 0.001). In conclusion, our data indicate that: patients with variant angina exhibit a marked and diffuse coronary narrowing of the coronary vessels during vasoconstrictor stimuli; focal spasm occurs more frequently at the level of atherosclerotic coronary segments, whether they are critical or not. An interaction between these 2 phenomena, ie atherosclerosis and abnormal vasoconstriction, is supposed to be a cause of the occurrence of focal coronary spasm in variant angina.

ST/HR slope during prostacyclin treatment: an improved method to identify patients with advanced coronary artery disease

Constriction of atherosclerotic coronary segments during exercise may further reduce coronary flow reserve in patients with coronary artery disease. This could influence the linear regression analysis of the heart rate-related changes in ST-segment depression (ST/HR slope) thereby limiting the accuracy of this method in identifying the severity of the disease. To test this hypothesis, the exercise related ST/HR slopes on placebo were compared with those obtained during coronary vasodilation induced by a prostacyclin analogue (iloprost 6 ng kg-1 min-1) in 42 anginal patients with documented coronary artery disease. In seven of these, the same protocol was repeated during right heart catheterization. The overall diagnostic accuracy of the ST/HR slope on iloprost was better than on placebo in patients with advanced coronary artery disease. This was due mainly to a consistent rightward shift of the ST/HR slope in patients with one- and two-vessel, but not three-vessel disease or left main stem disease. The reason for the greater effects of iloprost on ST/HR slopes in patients with a lesser degree of atherosclerosis remains unclear. However, coronary blood flow was higher during drug infusion, which suggests that iloprost may prevent the occurrence of dynamic coronary events able to reduce the maximum coronary flow reserve during exertion. This mechanism may be predominant in patients with minor coronary artery disease.

[Abnormal coronary response to vasomotor stimuli: analogies between variant angina and X syndrome]

The aim of this study was to evaluate the effects of hyperventilation (HV) and of ic nitroglycerin (NTG) on coronary diameters and hemodynamics in 32 patients with angina pectoris. Of these, 10 patients had stable angina and critical coronary artery disease (CAD, Group I), 12 patients with variant angina (VA) and no or minor coronary atherosclerosis (Group II), and 10 patients with angina and normal coronary arteries (syndrome X (SX), Group III). All patients underwent coronary angiography as well as right heart catheterization; measurements of left anterior descending coronary diameters (mid segment), great cardiac vein blood flow, aortic pressure and coronary resistance were performed on baseline, after HV and following NTG. HV caused coronary spasm in 4 patients with VA and significantly (p less than 0.001) reduced coronary diameters and regional blood flow both in Groups II and III, but not in Group I. NTG resulted in increased coronary diameters in all patients, however variations were greater in VA and SX (44 and 39%, respectively) than in Group I (18%; p less than 0.025). NTG induced an increase of coronary blood flow only in patients with CAD. We conclude that patients with VA and SX present a similar coronary response to vasomotor stimuli, either after HV or following NTG. Response is abnormal if compared to that of patients of group I, and it involves both epicardial and intramural coronary vessels. Thus, we suggest that SX and VA belong to a single pathogenetic entity with a spectrum of clinical manifestations.

Effect of oral levodopa and carbidopa on coronary spasm in variant angina pectoris

The effect of oral administration of 500 mg of levodopa with 50 mg of carbidopa, a peripheral dopadecarboxylase inhibitor, on coronary vasomotion during vasoconstrictor stimuli was examined in 15 patients with variant angina presenting with hyperventilation-induced myocardial ischemia. Patients were studied during 3 noninvasive sessions and 1 angiographic session. In all sessions the basic protocol consisted of provocation of coronary spasm by hyperventilation before and 2 hours after levodopa and carbidopa administration. During angiography, great cardiac vein blood flow, right atrial and aortic pressures were measured, and coronary angiograms were recorded at baseline and 1 to 4 minutes after each hyperventilation. Samples for dopamine plasma levels were drawn before and throughout the studies. In 3 selected patients, levodopa and carbidopa were associated with 30 mg of domperidone, an antagonist of dopamine peripheral receptors. Levodopa and carbidopa consistently prevented the occurrence of ischemia after hyperventilation in 6 of the 15 patients. This was due to inhibition of local coronary spasm in 2 patients and reduced coronary constriction in 4. Ischemia due to hyperventilation was still prevented despite addition of domperidone with levodopa and carbidopa. Plasma dopamine levels were 23 +/- 15 before and 739 +/- 284 pg/ml 2 hours after administration of levodopa and carbidopa. These findings are consistent with either a decreased central dopaminergic activity and associated disregulation of vasomotor tone, or a peripheral vasodilatory effect of increasing dopamine.(ABSTRACT TRUNCATED AT 250 WORDS)