Preprocedural serum levels of C-reactive protein predict early complications and late restenosis after coronary angioplasty

OBJECTIVES

We sought to investigate whether early and late outcome after percutaneous transluminal coronary angioplasty (PTCA) could be predicted by baseline levels of acute-phase reactants.

BACKGROUND

Although some risk factors for acute complications and restenosis have been identified, an accurate preprocedural risk stratification of patients undergoing PTCA is still lacking.

METHODS

Levels of C-reactive protein (CRP), serum amyloid A protein (SAA) and fibrinogen were measured in 52 stable angina and 69 unstable angina patients undergoing single vessel PTCA.

RESULTS

Tertiles of CRP levels (relative risk [RR] = 12.2, p < 0.001), systemic hypertension (RR = 4.3, p = 0.046) and female gender (RR = 4.1, p = 0.033) were the only independent predictors of early adverse events. Intraprocedural and in-hospital complications were observed in 22% of 69 patients with high serum levels (>0.3 mg/dl) of CRP and in none of 52 patients with normal CRP levels (p < 0.001). Tertiles of CRP levels (RR = 6.2, p = 0.001), SAA levels (RR = 6.0, p = 0.011), residual stenosis (RR = 3.2, p = 0.007) and acute gain (RR = 0.3, p = 0.01) were the only independent predictors of clinical restenosis. At one-year follow-up, clinical restenosis developed in 63% of patients with high CRP levels and in 27% of those with normal CRP levels (p < 0.001).

CONCLUSIONS

Preprocedural CRP level, an easily measurable marker of acute phase response, is a powerful predictor of both early and late outcome in patients undergoing single vessel PTCA, suggesting that early complications and clinical restenosis are markedly influenced by the preprocedural degree of inflammatory cell activation.

Comparison of insulin response to intravenous glucose in healed myocardial infarction, in "cooled-off" unstable and stable angina pectoris, and in healthy subjects

Fasting and postglucose hyperinsulinemia are recognized risk factors for acute coronary events. The insulin reactivity of patients with acute coronary syndromes, however, has not been carefully compared with that of patients with chronic stable angina. We used Bergman's minimal model to analyze the insulin response to intravenous glucose in 21 subjects: 8 patients with previous (>3 months) acute coronary syndrome but no effort-related angina; 6 patients with stable effort angina but no prior acute event; and 7 healthy controls. Diabetes mellitus, systemic hypertension, dyslipidemias, and obesity were excluded. All patients underwent coronary angiography. Insulin sensitivity, glucose effectiveness, and glucose tolerance were determined from insulin and glucose concentrations measured frequently up to 3 hours after a 0.33 g/kg intravenous glucose bolus. Patients with previous unstable angina or acute myocardial infarction had less extensive disease at angiography than patients with stable angina (p = 0.007). Both patient groups had higher basal and 180-minute insulinemia than controls (p <0.0007). However, patients with stable angina did not differ significantly from controls with regard to early and late insulinemic response to glucose. In contrast, patients with previous acute onset of ischemia had significantly greater 180-minute integrated insulinemia (p = 0.04) and reduced insulin sensitivity (p = 0.05) after the glucose challenge than did the stable angina group. These data suggest that patients with acute presentation of coronary artery disease, compared with patients with uncomplicated chronic stable angina, have an impaired insulin response to glucose despite less extensive coronary disease at angiography.

Atenolol versus amlodipine versus isosorbide-5-mononitrate on anginal symptoms in syndrome X

The effects of a beta blocker (atenolol), a calcium antagonist (amlodipine), and a nitrate (isosorbide-5-mononitrate) on anginal symptoms in 10 patients with syndrome X were assessed in a crossover, double-blind, randomized trial. Only atenolol was found to significantly improve chest pain episodes, suggesting that it should be the preferred drug when starting pharmacologic treatment of patients with syndrome X.

Circadian distribution of ischemic attacks and ischemia-related ventricular arrhythmias in patients with variant angina

BACKGROUND

There are limited data about the circadian distribution of ischemic episodes in patients with variant angina. Furthermore, no previous study investigated whether ischemia-related ventricular arrhythmias follow a circadian variation in these patients.

METHODS

The circadian variation of transient ischemia and ischemia-induced ventricular arrhythmias was assessed by cosinor methodology on 24-hour Holter recordings of 26 patients with variant angina.

RESULTS

On the whole, 301 ischemic episodes were detected in the population, with premature ventricular complexes occurring in 49 of them (16%). Ischemic episodes followed a typical circadian variation (acrophase hr 02:36, p < 0.01) in the total sample. However, a significant circadian variation of ischemic episodes was detectable in the 14 patients without (n = 167, acrophase hr 04:00, p < 0.0001), but not in the 12 patients with (n = 134, p = 0.14) hemodynamically significant coronary stenoses, independently of the location (anterior/inferior) of ischemia. There was no significant circadian variation of ischemia-related ventricular arrhythmias.

CONCLUSIONS

Among patients with variant angina, a clearcut circadian variation of ischemia is present in those without, but not in those with, hemodynamically significant coronary artery stenoses, thus suggesting that different pathophysiologic mechanisms may operate, at least in part, in triggering coronary spasm in these two subgroups of patients. There was no significant circadian variation of ischemia-related ventricular arrhythmias in these patients.

Allelic polymorphism of the interleukin-1 receptor antagonist gene in patients with acute or stable presentation of ischemic heart disease

BACKGROUND

One of the most potent pro-inflammatory mediators is the early-acting cytokine interleukin (IL)-1, whose actions are regulated by the structurally related IL-1 receptor antagonist (IL-1 Ra). IL-1 Ra is a competitive IL-1 inhibitor and a powerful anti-inflammatory agent. Several autoimmune and inflammatory diseases have been associated with an allelic polymorphism of the IL-1 Ra gene.

METHODS

We investigated the frequency of allele 2 of an intron 2 polymorphism of the IL-1 Ra gene in 115 consecutive patients with ischemic heart disease -74 of which had a previous myocardial infarction (48 +/- 11 years), 21 chronic stable angina (54 +/- 10 years), and 20 unstable angina (54 +/- 9 years)--and in 80 healthy controls, matched for age and sex to patients with myocardial infarction (47 +/- 10 years). An 86 base pair variable tandem repeat in intron 2 of the IL-1 Ra gene was determined by a polymerase chain reaction-based method.

RESULTS

The frequency of allele 2 was 15% in controls (carriage rate 25%) and 17% in ischemic heart disease patients (carriage rate 28%; p = 0.70). The allele 2 frequency did not differ significantly among the three patient groups. Among patients with myocardial infarction, the allele 2 frequency tended to be higher in patients with myocardial infarction < 40 years compared to those > or = 40 years (20 vs 11%, p = 0.20, OR 1.85, 95% CI 0.70-4.90), and in patients with C-reactive protein levels > or = 3 mg/l compared to those with values < 3 mg/l (31 vs 16%, p = 0.15, OR 2.38, 95% CI 0.64-9.25).

CONCLUSIONS

These data do not show a clear-cut association between the allele 2 of this IL-1 Ra gene polymorphism and ischemic heart disease. Among patients with myocardial infarction, the increased allele 2 frequency in those of younger age and with higher levels of C-reactive protein merits further investigation.

Preinfarction angina and improved reperfusion of the infarct-related artery

Preinfarction angina and early reperfusion of the infarct-related artery are major determinants of reduced infarct-size in patients with acute myocardial infarction. The beneficial effects of preinfarction angina on infarct size have been attributed to the development of collateral vessels and/or to post-ischemic myocardial protection. However, recently, a relation has been found between prodromal angina, faster coronary recanalization, and smaller infarcts in patients treated with rt-PA: those with preinfarction angina showed earlier reperfusion (p = 0.006) and a 50% reduction of CKMB-estimated infarct-size (p = 0.009) compared to patients without preinfarction angina. This intriguing observation is consistent with a subsequent observation of higher coronary recanalization rates following thrombolysis in patients with prodromal preinfarction angina compared to patients without antecedent angina. Recent findings in dogs show an enhanced spontaneous lysis of platelet-rich coronary thrombi with ischemic preconditioning, which is prevented by adenosine blockade, suggesting an antithrombotic effect of ischemic metabolites. Understanding the mechanisms responsible for earlier and enhanced coronary recanalization in patients with preinfarction angina may open the way to new reperfusion strategies.

The variable role of inflammation in acute coronary syndromes and in restenosis

Inflammation has recently been shown to be an important pathogenetic component of atherosclerosis in general and of acute coronary syndromes in particular. Not only activated inflammatory cells have been found in the plaques, but, more interestingly, also activated circulating inflammatory cells as well as elevated levels of systemic markers of inflammation have been described. Among these, C-reactive protein is of clinical value, as its levels are associated with the outcome. Inflammation is important also in triggering the mechanisms of restenosis and CRP has been recently described as a useful pre-procedure marker of risk of restenosis. The cause of inflammation, what triggers the shift from an indolent disease to the acute coronary syndromes and the more appropriate therapies are still a matter of debate.

Single-bolus tenecteplase compared with front-loaded alteplase in acute myocardial infarction: the ASSENT-2 double-blind randomised trial

BACKGROUND

Bolus fibrinolytic therapy facilitates early efficient institution of reperfusion therapy. Tenecteplase is a genetically engineered variant of alteplase with slower plasma clearance, better fibrin specificity, and high resistance to plasminogen-activator inhibitor-1. We did a double-blind, randomised, controlled trial to assess the efficacy and safety of tenecteplase compared with alteplase.

METHODS

In 1021 hospitals, we randomly assigned 16,949 patients with acute myocardial infarction of less than 6 h duration rapid infusion of alteplase (< or = 100 mg) or single-bolus injection of tenecteplase (30-50 mg according to bodyweight). All patients received aspirin and heparin (target activated partial thromboplastin time 50-75 s). The primary outcome was equivalence in all-cause mortality at 30 days.

FINDINGS

Covariate-adjusted 30-day mortality rates were almost identical for the two groups--6.18% for tenecteplase and 6.15% for alteplase. The 95% one-sided upper boundaries of the absolute and relative differences in 30-day mortality were 0.61% and 10.00%, respectively, which met the prespecified criteria of equivalence (1% absolute or 14% relative difference in 30-day mortality, whichever difference proved smaller). Rates of intracranial haemorrhage were similar (0.93% for tenecteplase and 0.94% for alteplase), but fewer non-cerebral bleeding complications (26.43 vs 28.95%, p=0.0003) and less need for blood transfusion (4.25 vs 5.49%, p=0.0002) were seen with tenecteplase. The rate of death or non-fatal stroke at 30 days was 7.11% with tenecteplase and 7.04% with alteplase (relative risk 1.01 [95% CI 0.91-1.13]).

INTERPRETATION

Tenecteplase and alteplase were equivalent for 30-day mortality. The ease of administration of tenecteplase may facilitate more rapid treatment in and out of hospital.

Elevated levels of C-reactive protein before coronary artery bypass grafting predict recurrence of ischemic events

C-reactive protein was measured in 86 patients undergoing coronary artery bypass graft surgery. Patients were followed up for 3.2 years (range 1 to 6). Patients with C-reactive protein > or = 3 mg/L had significantly increased risk of recurrent ischemia at 1 to 6 years after intervention.

A simple assay for platelet-mediated hemostasis in flowing whole blood (PFA-100): reproducibility and effects of sex and age

BACKGROUND

A simple assay for platelet-mediated hemostasis in flowing blood (PFA-100) has become available. Whole blood is aspirated through the central opening of a membrane coated with platelet agonists; the time required for a platelet thrombus to occlude the opening is defined as closure time; the shorter the closure time the greater the platelet aggregability. There are limited data on the normal range of values for this test, and the effects of sex and age are not known. The aim of this study was to determine the effects of sex and age on closure time in normal volunteers and to assess the reproducibility of the test in our laboratory.

METHODS

Closure time using collagen/adenosine-5'-diphosphate was measured in 62 apparently healthy individuals 35 to 75 years of age (11 men and 17 women < 55 years and 22 men and 12 women > 55 years).

RESULTS

Closure time was 96.6 +/- 24 s in men and 93.1 +/- 16 s in women (p = 0.20). In the entire group, closure time did not significantly correlate with age (r = -0.17, p = 0.18). However, men < 55 years tended to have a longer closure time than men > 55 years (109.7 +/- 23 vs 90.0 +/- 22 s, p = 0.08), whereas in women closure time was similar in those younger or older than 55 years (93.1 +/- 16 vs 93.3 +/- 18 s, respectively). In 20 samples tested in duplicate, the mean closure time was 80.9 +/- 10 s on the first determination and 81.5 +/- 12 s on the second (r = 0.89, p < 0.001). There was no significant correlation between closure time and hematocrit, platelet number, mean platelet volume, or leukocyte count.

CONCLUSIONS

The platelet function analyzer PFA-100 showed a good reproducibility in apparently healthy subjects. No significant difference in closure time was found between men and women, nor between subjects younger or older than 55 years, although a tendency towards shorter values was found in older compared with younger men.

Racial heterogeneity in coronary artery vasomotor reactivity: differences between Japanese and Caucasian patients

Japanese investigators have provided a substantial contribution in the understanding of coronary vasomotor reactivity. On occasions, their findings have been at variance with those undertaken on caucasian patients, raising speculation that vasomotor differences between races may exist. In a comparative review of the published literature, we evaluated the vasoreactive differences among Japanese and caucasian patients with variant angina or myocardial infarction. In variant angina, Japanese patients appear to have diffusely hyperreactive coronary arteries compared with caucasian people, manifested by their segmental rather than focal spasm, hyperreactive nonspastic vessels and multivessel spasm. These differences may reflect the increased basal tone among Japanese variant angina patients and may relate to controversial differences in endothelial nitric oxide production or autonomic nervous system activity. Provocative vasomotor studies of Japanese patients with a recent myocardial infarction report a higher incidence of inducible spasm than caucasian studies, an observation recently supported by a controlled study. Furthermore, the hyperreactivity was diffuse, occurring in both non-infarct- and infarct-related vessels. These observations support the existence of racial coronary vasomotor reactivity differences but require confirmation in further prospectively conducted studies.

Marked elevation of myocardial trace elements in idiopathic dilated cardiomyopathy compared with secondary cardiac dysfunction

OBJECTIVES

We sought to investigate the possible pathogenetic role of myocardial trace elements (TE) in patients with various forms of cardiac failure.

BACKGROUND

Both myocardial TE accumulation and deficiency have been associated with the development of heart failure indistinguishable from an idiopathic dilated cardiomyopathy.

METHODS

Myocardial and muscular content of 32 TE has been assessed in biopsy samples of 13 patients (pts) with clinical, hemodynamic and histologic diagnosis of idiopathic dilated cardiomyopathy (IDCM), all without past or current exposure to TE. One muscular and one left ventricular (LV) endomyocardial specimen from each patient, drawn with metal contamination-free technique, were analyzed by neutron activation analysis and compared with 1) similar surgical samples from patients with valvular (12 pts) and ischemic (13 pts) heart disease comparable for age and degree of LV dysfunction; 2) papillary and skeletal muscle surgical biopsies from 10 pts with mitral stenosis and normal LV function, and 3) LV endomyocardial biopsies from four normal subjects.

RESULTS

A large increase (>10,000 times for mercury and antimony) of TE concentration has been observed in myocardial but not in muscular samples in all pts with IDCM. Patients with secondary cardiac dysfunction had mild increase (< or = 5 times) of myocardial TE and normal muscular TE. In particular, in pts with IDCM mean mercury concentration was 22,000 times (178,400 ng/g vs. 8 ng/g), antimony 12,000 times (19,260 ng/g vs. 1.5 ng/g), gold 11 times (26 ng/g vs. 2.3 ng/g), chromium 13 times (2,300 ng/g vs. 177 ng/g) and cobalt 4 times (86,5 ng/g vs. 20 ng/g) higher than in control subjects.

CONCLUSIONS

A large, significant increase of myocardial TE is present in IDCM but not in secondary cardiac dysfunction. The increased concentration of TE in pts with IDCM may adversely affect mitochondrial activity and myocardial metabolism and worsen cellular function.

Increasing levels of interleukin (IL)-1Ra and IL-6 during the first 2 days of hospitalization in unstable angina are associated with increased risk of in-hospital coronary events

BACKGROUND

A growing body of evidence suggests a role for inflammation in acute coronary syndromes. The aim of this study was to assess the role of proinflammatory cytokines, their time course, and their association with prognosis in unstable angina.

METHODS AND RESULTS

We studied 43 patients aged 62+/-8 years admitted to our coronary care unit for Braunwald class IIIB unstable angina. In each patient, serum levels of interleukin-1 receptor antagonist (IL-1Ra), interleukin-6 (IL-6) (which represent sensitive markers of biologically active IL-1beta and tumor necrosis factor-alpha levels, respectively), and troponin T were measured at entry and 48 hours after admission. Troponin T-positive patients were excluded. Patients were divided a posteriori into 2 groups according to their in-hospital outcome: group 1 comprised 17 patients with an uneventful course, and group 2 comprised 26 patients with a complicated in-hospital course. In group 1, mean IL-1Ra decreased at 48 hours by 12%, and IL-6 diminished at 48 hours by 13%. In group 2, IL-1Ra and IL-6 entry levels were higher than in group 1 and increased respectively by 37% and 57% at 48 hours (P<0.01).

CONCLUSIONS

These findings indicate that although they receive the same medical therapy as patients who do not experience an in-hospital event, patients with unstable angina and with complicated in-hospital courses have higher cytokine levels on admission. A fall in IL-1Ra and IL-6 48 hours after admission was associated with an uneventful course and their increase with a complicated hospital course. These findings may suggest novel therapeutic approaches to patients with unstable angina.

Homocysteine and arterial occlusive disease: a concise review

Many cross-sectional and prospective studies have shown that raised serum/plasma levels of total homocysteine increase the risk of coronary, cerebral, and peripheral artery disease. The risk associated with hyperhomocysteinemia appears to be concentration-dependent and not attributable to traditional risk factors. The odds ratio for ischemic heart disease has been estimated to be 1.4 for every 5 mumol/l increase of total plasma homocysteine. Median fasting total plasma homocysteine in adult males is approximately 10 mumol/l. Mild hyperhomocysteinemia is estimated to occur in 5-10% of the general population. Plasma concentrations are increased as a result of age, male gender, impaired renal function, low vitamin B intake, and genetically-determined defects of the enzymes involved in homocysteine metabolism. Folate supplements can reduce total homocysteine levels by approximately 25%. Studies in vitro and in vivo indicate that homocysteine can impair endothelial function. Despite increasing recognition of hyperhomocysteinemia as a risk factor for arterial occlusive disease, irrefutable proof that mild hyperhomocysteinemia contributes directly to the pathogenesis of atherothrombosis will come if interventions to lower total homocysteine reduce cardiovascular events. Family studies may also provide evidence of causality if genetic causes of hyperhomocysteinemia are found to segregate with disease.

In vitro hyperreactivity to lipopolysaccharide in patients with history of unstable angina is not associated with seropositivity for Cytomegalovirus, Helicobacter pylori and Chlamydia pneumoniae

BACKGROUND

Inflammation and possibly chronic infections are associated with acute coronary syndromes; however, the mechanisms responsible for this association are not yet fully elucidated. The aim of this study was to assess whether the hyperreactivity of the inflammatory system, that we have shown in unstable patients with persistently elevated C-reactive protein and with recurrence of symptoms, was associated with chronic infection.

METHODS

In 20 unstable angina patients seropositivity and antibody levels vs Cytomegalovirus, Helicobacter pylori and Chlamydia pneumoniae were measured and correlated with the interleukin-6 production in vivo in 1 ml of whole blood stimulated with 0.1 microgram lipopolysaccharide for 4 hours.

RESULTS

No positive correlation was found between antibody titer and interleukin-6 levels. No correlation was also found between seropositivity to Cytomegalovirus, Helicobacter pylori or Chlamydia pneumoniae and interleukin-6 levels.

CONCLUSIONS

Our study suggests that seropositivity for infective agents, including Chlamydia pneumoniae, does not affect the monocyte response to lipopolysaccharide and thus cannot account for the enhanced interleukin-6 production observed in unstable angina patients with raised levels of C-reactive protein and worse prognosis, and suggests the predominant role of the individual response to different stimuli.

Cell death in acromegalic cardiomyopathy

BACKGROUND

Prolonged untreated acromegaly leads to a nonspecific myopathy characterized by ventricular dysfunction and failure. However, the mechanisms responsible for the alterations of cardiac pump function remain to be defined. Because cell death is implicated in most cardiac disease processes, the possibility has been raised that myocyte apoptosis may occur in the acromegalic heart, contributing to the deterioration of ventricular hemodynamics.

METHODS AND RESULTS

Ten acromegalic patients with diastolic dysfunction and 4 also with systolic dysfunction were subjected to electrocardiography, Holter monitoring, 2-dimensional echocardiography, cardiac catheterization, and biventricular and coronary angiography before surgical removal of a growth hormone-secreting pituitary adenoma. Endomyocardial biopsies were obtained and analyzed quantitatively in terms of tissue scarring and myocyte and nonmyocyte apoptosis. Myocardial samples from papillary muscles of patients who underwent valve replacement for mitral stenosis were used for comparison. The presence of apoptosis in myocytes and interstitial cells was determined by confocal microscopy with the use of 2 histochemical methods, consisting of terminal deoxynucleotidyl transferase (TdT) assay and Taq probe in situ ligation. Acromegaly was characterized by a 495-fold and 305-fold increase in apoptosis of myocytes and nonmyocytes, respectively. The magnitude of myocyte apoptosis correlated with the extent of impairment in ejection fraction and the duration of the disease. A similar correlation was found with the magnitude of collagen accumulation, indicative of previous myocyte necrosis. Myocyte death was independent from the hormonal levels of growth hormone and insulin-like growth factor-1. Apoptosis of interstitial cells did not correlate with ejection fraction.

CONCLUSIONS

Myocyte cell death, apoptotic and necrotic in nature, may be critical for the development of ventricular dysfunction and its progression to cardiac failure with acromegaly.

Global biventricular dysfunction in patients with asymptomatic coronary artery disease may be caused by myocarditis

BACKGROUND

The causal role of asymptomatic critical coronary artery obstruction in patients presenting with severe global biventricular dysfunction but no evidence of myocardial infarction is uncertain.

METHODS AND RESULTS

Among 291 patients aged >40 years undergoing a noninvasive (2-dimensional echocardiography) and invasive (catheterization, coronary angiography, and biventricular endomyocardial biopsy, 6 to 8 samples/patient) cardiac study because of progressive heart failure (New York Heart Association functional class III or IV) with global biventricular dysfunction and no history of myocardial ischemic events, 7 patients (2.4%; 7 men; mean age, 49+/-6.9 years) had severe coronary artery disease (3 vessels in 4 patients; 2 vessels in 1 patient, proximal occlusion of left anterior descending coronary artery in 2 patients). Left ventricular end-diastolic diameter and ejection fraction by 2-dimensional echocardiography were 73+/-10.5 mm and 23+/-6.5%, respectively, and right ventricular end-diastolic diameter and ejection fraction were 39+/-7 mm and 29+/-7.2%, respectively. Biopsy specimens showed extensive lymphocytic infiltrates with focal myocytolysis meeting the Dallas criteria for myocarditis in all patients (in 5 patients with and 2 patients without fibrosis). Cardiac autoantibodies were detected with indirect immunofluorescence in the serum of 2 patients with active myocarditis. The 2 patients with active inflammation received prednisone (1 mg. kg-1. d-1 for 4 weeks followed by 0.33 mg. kg-1. d-1 for 5 months) and azathioprine (2 mg. kg-1. d-1 for 5 months) in addition to conventional drug therapy for heart failure. At 8-month overall follow-up, cardiac volume and function improved considerably in immunosuppressed patients but remained unchanged in conventionally treated patients, of whom 1 died.

CONCLUSIONS

Global biventricular dysfunction in patients with severe asymptomatic coronary artery disease and no evidence of previous myocardial infarction may be caused by myocarditis. Histologic findings may influence the treatment.

Additional predictive value of heart rate variability in high-risk patients surviving an acute myocardial infarction

The aim of this study was to investigate the usefulness of heart rate variability (HRV) in predicting cardiac mortality in patients with a recent acute myocardial infarction at high risk of events. Time- and frequency-domain HRV was assessed on 24-hour pre-discharge Holter recording of 81 patients (mean age 65 +/- 10 years, 76.5% males) with 1) a recent acute myocardial infarction, and 2) left ventricular ejection fraction < 40% and/or a number of premature ventricular beats > or = 10/hour. There were 15 total cardiac deaths (18.5%) in a follow-up time of 29 +/- 15 months (range 6 to 48 months), with sudden death occurring in 11 patients (13.6%). Median values of low frequency (LF) were lower in patients with, compared to those without, total (p = 0.04) and sudden (p = 0.02) cardiac death. Similarly the low frequency/high frequency (LF/HF) ratio was lower in patients with fatal events (p = 0.03 and p = 0.02, respectively). Furthermore, mean of the standard deviations of all RR intervals for all 5-min segments < 20 ms, among time-domain variables, and very-low frequency (VLF) < 18 ms, among frequency-domain variables, significantly predicted cardiac death (relative risk-RR 2.94, p = 0.03; and RR 3.85, p < 0.005, respectively). Furthermore, VLF < 18 ms and LF/HF ratio < 1.05 significantly predicted the occurrence of sudden death (RR 3.52, p = 0.04; and RR 3.49, p = 0.04, respectively). Thus, our data show that HRV analysis is a useful tool for identifying patients with an actual increased risk of fatal cardiac events among patients who are basically considered at high risk according to the presence of an impaired left ventricular function and/or frequent ventricular arrhythmias.

Elevated levels of C-reactive protein at discharge in patients with unstable angina predict recurrent instability

BACKGROUND

In a group of patients admitted for unstable angina, we investigated whether C-reactive protein (CRP) plasma levels remain elevated at discharge and whether persistent elevation is associated with recurrence of instability.

METHODS AND RESULTS

We measured plasma levels of CRP, serum amyloid A protein (SAA), fibrinogen, total cholesterol, and Helicobacter pylori and Chlamydia pneumoniae antibody titers in 53 patients admitted to our coronary care unit for Braunwald class IIIB unstable angina. Blood samples were taken on admission, at discharge, and after 3 months. Patients were followed for 1 year. At discharge, CRP was elevated (>3 mg/L) in 49% of patients; of these, 42% had elevated levels on admission and at 3 months. Only 15% of patients with discharge levels of CRP <3 mg/L but 69% of those with elevated CRP (P<0.001) were readmitted because of recurrence of instability or new myocardial infarction. New phases of instability occurred in 13% of patients in the lower tertile of CRP (</=2.5 mg/L), in 42% of those in the intermediate tertile (2.6 to 8.6 mg/L), and in 67% of those in the upper tertile (>/=8.7 mg/L, P<0.001). The prognostic value of SAA was similar to that of CRP; that of fibrinogen was not significant. Chlamydia pneumoniae but not Helicobacter pylori antibody titers significantly correlated with CRP plasma levels.

CONCLUSIONS

In unstable angina, CRP may remain elevated for at >/=3 months after the waning of symptoms and is associated with recurrent instability. Elevation of acute-phase reactants in unstable angina could represent a hallmark of subclinical persistent instability or of susceptibility to recurrent instability and, at least in some patients, could be related to chronic Chlamydia pneumoniae infection.

Comparison of response to serotonin of radial artery grafts and internal mammary grafts to native coronary arteries and the effect of diltiazem

We studied the response of radial artery (RA) or left internal mammary artery grafts to the intraluminal infusion of serotonin in 22 consecutive patients 1 year after the operation, subsequently evaluating the effect of diltiazem in 9 patients. Serotonin causes a significant vasoconstriction of the RA grafts, but not of the left internal mammary artery grafts, whereas oral diltiazem treatment does not prevent the effect of the higher dose of serotonin on RA grafts.

Histologically proven myocarditis in patients with biventricular dysfunction and severe asymptomatic coronary artery disease

The aim of our study was to investigate the pathogenesis of the global biventricular dysfunction observed in patients with critical coronary artery stenosis, but no evidence of myocardial ischemia or infarction. From January 1992 to January 1997, among consecutive patients undergoing invasive cardiac study including biventricular endomyocardial biopsy because of progressive heart failure (NYHA functional class III-IV) associated with biventricular dysfunction and no history of myocardial ischemic events, 7 patients had severe coronary artery disease (three vessel 4 patients; two vessel 1 patient, proximal occlusion of left anterior descending artery 2 patients). At two-dimensional echocardiography left and right ventricular end-diastolic diameter were 73 +/- 10.5 and 39 +/- 7 mm, respectively, left ventricular ejection fraction was 0.23 +/- 6.5 and right ventricular ejection fraction was 0.29 +/- 7.2. Histology showed extensive lymphocytic infiltrates with focal myocytolysis meeting the Dallas criteria for myocarditis in all patients. Two patients with active inflammation received prednisone and azathioprine in addition to conventional drug therapy for heart failure. At 6-month follow-up cardiac volume and function improved in immunosuppressed patients (left ventricular ejection fraction from 15 to 50% and from 20 to 38%, respectively) while they remained unchanged in conventionally treated patients. In conclusion, global biventricular dysfunction in patients with severe asymptomatic coronary artery disease and no evidence of previous myocardial infarction may be caused by myocarditis rather than by myocardial ischemia or hibernation.

Enhanced inflammatory response to coronary angioplasty in patients with severe unstable angina

BACKGROUND

Systemic markers of inflammation have been found in unstable angina. Disruption of culprit coronary stenoses may cause a greater inflammatory response in patients with unstable than those with stable angina. We assessed the time course of C-reactive protein (CRP), serum amyloid A protein (SAA), and interleukin-6 (IL-6) after single-vessel PTCA in 30 patients with stable and 56 patients with unstable angina (protocol A). We also studied 12 patients with stable and 15 with unstable angina after diagnostic coronary angiography (protocol B).

METHODS AND RESULTS

Peripheral blood samples were taken before and 6, 24, 48, and 72 hours after PTCA or angiography. In protocol A, baseline CRP, SAA, and IL-6 levels were normal in 87% of stable and 29% of unstable patients. After PTCA, CRP, SAA, and IL-6 did not change in stable patients and unstable patients with normal baseline levels but increased in unstable patients with raised baseline levels (all P<0.001). In protocol B, CRP, SAA, and IL-6 did not change in stable angina patients after angiography but increased in unstable angina patients (all P<0.05). Baseline CRP and SAA levels correlated with their peak values after PTCA and angiography (all P<0.001).

CONCLUSIONS

Our data suggest that plaque rupture per se is not the main cause of the acute-phase protein increase in unstable angina and that increased baseline levels of acute-phase proteins are a marker of the hyperresponsiveness of the inflammatory system even to small stimuli. Thus, an enhanced inflammatory response to nonspecific stimuli may be involved in the pathogenesis of unstable angina.

Prognostic role of heart rate variability in patients with a recent acute myocardial infarction

A low heart rate variability (HRV) has been shown to be a powerful predictor of cardiac events in patients surviving an acute myocardial infarction (MI), but it is not clear yet which among the HRV parameters has the best predictive value. Time domain and frequency domain HRV was assessed on 24-hour predischarge Holter recording of 239 patients with a recent MI. Patients were followed up for 6 to 54 months (median 28), during which 26 deaths (11%) occurred, 19 of which were cardiac in origin and 12 were sudden. Most HRVs did not show any difference between patients with or without mortality end points, but the average low-frequency and low-frequency/high-frequency ratio was lower in patients with events. However, when dichotomized according to cut points that maximized the risk of sudden death, several HRVs were significantly predictive of clinical end points. Overall, the mean of the standard deviations of all RR intervals for all 5-minute segments and the standard deviation of the mean RR intervals for all 5-minute segments were the time domain variables most significantly associated with mortality end points, whereas very low frequency was the most predictive frequency domain variable. Compared with the best time domain variables, very low frequency showed a better sensitivity (0.27 to 0.42 vs 0.19 to 0.33) for end points with only a small loss in specificity (0.92 vs 0.96). On multivariate Cox proportional analysis, a left ventricular ejection fraction <40% and a number of ventricular premature beats > or = 10/hour were the most powerful independent predictors for all end points, whereas no HRV was independently associated with the events. A low frequency/high frequency ratio < 1.05 only had a borderline association with sudden death (RR = 2.86, p = 0.076). Our data show a strong association between HRV and mortality in patients surviving a recent MI, with a slight better sensitivity of frequency domain analysis. In our study, however, HRV did not add independent prognostic information to more classic prognostic variables (e.g., left ventricular function and ventricular arrhythmias).

[The absence of a procoagulant effect after TNK-t-PA: a comparison with streptokinase and rt-PA]

A limitation of current fibrinolytic drugs is the procoagulant activity induced by their administration. TNK is a mutant of tissue plasminogen activator (t-PA) with high fibrin specificity, resistance to plasminogen activator inhibitor-1 and slow plasma clearance, which is administered in a single intravenous bolus. In this study we investigated the procoagulant effect of TNK-t-PA compared to streptokinase, rt-PA or no thrombolysis. Twenty-nine patients with acute myocardial infarction, treated within 6 hours of symptom onset with 1.5 MU streptokinase over 1 hour (n = 12), 100 mg rt-PA in 1.5 hours (n = 12) or 30-40 mg TNK-t-PA in 15 s (n = 5), were studied and compared to 7 patients with contraindications to thrombolysis (control group). All patients received a similar i.v. heparin regimen for at least 24 hours. Blood samples were drawn before the start of treatment (time 0) and after 2 hours. Thrombin formation was assessed as plasma concentrations of thrombin-antithrombin complex (TAT). The four patient groups did not differ significantly in age, sex, time to treatment, infarct location, and TAT values at time 0 (mean value +/- standard error of the mean 9 +/- 2 micrograms/l). Mean TAT levels at 2 hours were 26 +/- 6 micrograms/l in streptokinase treated patients (p = 0.005 vs time 0), 21 +/- 4 micrograms/l in rt-PA treated patients (p < 0.05 vs time 0), 5 +/- 0.6 micrograms/l in TNK treated patients, and 4 +/- 0.4 micrograms/l in controls (NS vs time 0 for TNK and controls). In conclusion, our data suggest that, in patients with acute myocardial infarction, bolus TNK-t-PA, unlike streptokinase or rt-PA infusions, is devoid of procoagulant effects, evaluated 2 hours after its administration.

Immune system activation follows inflammation in unstable angina: pathogenetic implications

OBJECTIVES

The aim of this study was to assess the relations between inflammation, specific immune response and clinical course in unstable angina (UA).

BACKGROUND

Several studies suggest that either inflammation and/or T-cell activation might have a pathogenetic role in UA, but neither their potential reciprocal connection nor their relation to the clinical course is known.

METHODS

Serum levels of C-reactive protein (CRP) (inflammation), IgG, IgA, IgM, C3, C4 (humoral immunity), IL-2 and the percentage of CD4+, CD8+ and CD3+/DR+ T-cells (cell-mediated immunity) were measured in 35 patients with UA and 35 patients with chronic stable angina (CSA) during a period of 6 months.

RESULTS

The CRP levels and the main specific immune markers (CD4+ and CD3+/DR+ cells, IL-2 and IgM) were higher in unstable than in stable angina. In UA, the serum levels of IgM and IL-2 and the percentage of double positive CD3+/DR+ significantly increased at 7 to 15 days, and returned to baseline at 6 months. The increment of circulating activated T cells (CD3+/ DR+) in UA was inversely related to the admission levels of CRP (r=-0.63, p=0.003) and associated with a better outcome.

CONCLUSIONS

Our data suggest that the inflammatory component systemically detectable in UA may be antigen-related and that the magnitude of the immune response correlates with the clinical outcome of instability.

Necrotizing myocardial vasculitis in Churg-Strauss syndrome: clinicohistologic evaluation of steroids and immunosuppressive therapy

Treatment of cardiac dysfunction associated with Churg-Strauss syndrome (CSS) is empiric since the histologic findings provided by endomyocardial biopsy are rare and often nondiagnostic. Myocardial necrotizing vasculitis presenting as restrictive cardiomyopathy has not been reported before. A case of CSS, presenting with fever and progressive heart failure due to pericarditis, eosinophilic endomyocarditis, and myocardial necrotizing vasculitis, is reported. Cardiac involvement assessed by noninvasive (cardiac two-dimensional echocardiogram and nuclear magnetic resonance [NMR] imaging) and invasive (cardiac catheterization, angiography, and biopsy) studies showed a moderate degree of pericardial effusion and left ventricular (LV) dysfunction (ejection fraction 0.40), severe diastolic dysfunction (increased right and LV filling pressure with a dip and plateau pattern) and a severe reduction of cardiac index (1.6 L/min/m2). Histologic characteristics showed marked eosinophilic infiltration of the endocardium and myocardium with myocitolysis and fibrinoid necrosis of arterioles, venules, and capillaries. Combination therapy of steroids and cyclophosphamide resulted in both a clinical (regression of pericardial effusion, normalization of systolic and diastolic dysfunction, and increase of cardiac index to 2.8 L/min/m2) and histologic (sequential endomyocardial biopsies at 1, 3, and 6 months of follow-up) resolution of cardiac involvement. No recurrences were registered at 12-month follow-up with the patient receiving a maintenance drug regimen.

Helicobacter pylori infection and ischaemic heart disease

Helicobacter pylori infection is probably one of the most widely spread infectious diseases in man and a growing body of knowledge provides evidence in favour of a causal link between this infection and the majority of upper gastrointestinal conditions. For example, we now know that peptic ulcer disease is an infectious disease; if the infection is diagnosed and treated, ulcer can be cured. On the other hand, in recent years, a number of epidemiological studies have focused on the possible relation between ischaemic heart disease and several infectious disorders, such as chronic dental infections, Cytomegalovirus, Coxsackie viruses, Chlamydia and, finally Helicobacter pylori. The results of studies on the association between ischaemic heart disease and Helicobacter pylori have, in particular, often been contradictory, and only some studies adjusted the results for confounding factors, and the adjustment of the results in some cases modified the association. In conclusion, even if coronary atherosclerosis may now be considered as an inflammatory process, according to several histologic and pathophysiologic studies, we cannot, for the moment, be sure that it is an infectious disease.

Incremental prognostic value of serum levels of troponin T and C-reactive protein on admission in patients with unstable angina pectoris

Management of unstable angina is largely determined by symptoms, yet some symptomatic patients stabilize, whereas others develop myocardial infarction after waning of symptoms. Therefore, markers of short-term risk, available on admission, are needed. The value of 4 prognostic indicators available on admission (pain in the last 24 hours, electrocardiogram [ECG], troponin T, and C-reactive protein [CRP]), and of Holter monitoring available during the subsequent 24 hours was analyzed in 102 patients with Braunwald class IIIB unstable angina hospitalized in 4 centers. The patients were divided into 3 groups: group 1, 27 with pain during the last 24 hours and ischemic electrocardiographic changes; group 2, 45 with pain or electrocardiographic changes; group 3, 30 with neither pain nor electrocardiographic changes. Troponin T, CRP, ECG on admission, and Holter monitoring were analyzed blindly in the core laboratory. Fifteen patients developed myocardial infarction: 22% in group 1, 13% in group 2, and 10% in group 3. Twenty-eight patients underwent revascularization: 37% in group 1, 35% in group 2, and 7% in group 2 (p <0.01 between groups 1 or 2 vs group 3). Myocardial infarction was more frequent in patients with elevated troponin T (50% vs 9%, p=0.001) and elevated CRP (24% vs 4%, p= 0.01). Positive troponin T or CRP identified all myocardial infarctions in group 3. Only 1 of 46 patients with negative troponin T and CRP developed myocardial infarction. Among the indicators available on admission, multivariate analysis showed that troponin T (p=0.02) and CRP (p=0.04) were independently associated with myocardial infarction. Troponin T had the highest specificity (92%), and CRP the highest sensitivity (87%). Positive results on Holter monitoring were also associated with myocardial infarction (p=0.003), but when added to troponin T and CRP, increased specificity and positive predictive value by only 3%. Thus, in patients with class IIIB unstable angina, among data potentially available on admission, serum levels of troponin T and CRP have a significantly greater prognostic accuracy than symptoms and ECGs. Holter monitoring, available 24 hours later, adds no significant information.

The role of plaque fissures in unstable angina: fact or fiction?

Several factors may contribute to the development of unstable angina. These include underlying atherosclerosis, mural platelet thrombosis, dynamic stenosis, occlusive spasm and microvascular dysfunctions. Of these, thrombosis is the most visible event, but its actual causes remain elusive. Plaque fissure is widely assumed to be the cause of unstable angina. However, studies have shown no evidence of plaque fissure in about 40% of patients dying from acute coronary syndromes and, conversely, fissured plaques have been found in 10-25% of individuals dying of non-cardiac causes. An inflammatory process may activate the coronary intima and the haemostatic system to produce a platelet-rich thrombus. Activated inflammatory cells produce cytokines which can activate the endothelium making it prothrombotic and vasoconstrictive; they can also produce metalloproteases that can lyse the interstitial matrix. Thus, inflammatory lysis of thin atherosclerotic plaques may also cause plaque fissure at one or more sites. Waxing and waning inflammatory activity may explain the multi-layered thrombi and multiple simultaneous coronary fissure and thrombi that have been described in patients with acute coronary syndromes.

Role of different determinants of psychological distress in acute coronary syndromes

OBJECTIVES

The aim of this study was to examine the prevalence of psychological distress and of its major determinants in acute coronary patients and in a control group.

BACKGROUND

The prevalence and major determinants of psychological distress in acute coronary patients are not clear.

METHODS

One hundred and thirty cardiac patients (110 men, age 56+/-9; 85 with acute myocardial infarction and 45 with unstable angina) and 102 controls hospitalized for acute trauma (70 men, age 55+/-9 years) were studied and the level of psychological distress estimated by a Modified Maastricht Questionnaire, self-ratings and ratings by a close relative. Major determinants of psychological distress were assessed by the Life Events Assessment, the Social Support Questionnaire and the Ways of Coping Checklist.

RESULTS

The average level of psychological distress was significantly higher (p < 0.001) in coronary patients than in controls in all tests (self-evaluation=7.1+/-2.3 vs 4.3+/-2.4; relative-evaluation = 7.4+/-2.4 vs 4.2+/- 2.5; Modified Maastricht Questionnaire=91+/-32 vs 59+/-30). Cardiac patients reported significantly higher (p < 0.05) levels of social isolation (28.9+/-11.1 vs 23.4+/-8.8), self-blame (7.2+/-1.9 vs 5.8+/- 1.6) and avoidance (21.1+/-3.5 vs 18.9+/-3) and more painful life events (3.9+/-3.8 vs 2.6+/-2.2), than controls. However, not all patients had evidence of distress; indeed, cluster analysis identified a subgroup that comprised 75% of controls and 25% of cardiac patients with no determinants eliciting distress, while the other four subgroups, with one or more determinants of distress, comprised about 75% of patients and only 25% of controls.

CONCLUSIONS

These results show that a high level of psychological distress is detectable in about 75% of patients with acute myocardial infarction or unstable angina and is related to one or more major determinants.

Angiographic characteristics of infarct-related and non-infarct-related stenoses in patients in whom stable angina progressed to acute myocardial infarction

BACKGROUND

In patients with coronary artery disease, angiographic and postmortem studies have shown that coronary stenoses in infarct-related arteries often have complex morphology. It is not known whether in patients with multivessel disease stenosis morphology in non-infarct-related arteries is different from those of the infarct-related arteries.

METHODS AND RESULTS

In 24 consecutive patients we examined the angiographic characteristics of both the infarct-related stenoses and non-infarct-related stenoses before and after spontaneous acute myocardial infarction, by visual inspection and computerized edge detection of coronary angiograms. Before myocardial infarction, the severity of the infarct-related stenoses was <50% in 14 patients and > or =50% in 10 patients (p=not significant) and of non-infarct-related stenoses was <50% in 16 and > or=50% in 13. A significantly greater proportion of infarct-related stenoses with severity > or =50% progressed to non-Q-wave than to Q-wave myocardial infarction (71% vs 50%, p < 0.05). Before myocardial infarction, the percentage of concentric, eccentric, and irregular infarct-related stenoses was 8%, 13%, and 50%, respectively, whereas in the non-infarct-related stenoses it was 62%, 17%, and 21%, respectively (p < 0.01). A similar proportion of irregular morphology progressed to Q-wave or non-Q-wave myocardial infarction.

CONCLUSIONS

In patients with stable angina who had acute myocardial infarction develop, the infarct-related and non-infarct-related stenoses on average are similar in severity but different in morphology. Nonsevere stenoses more frequently progress to Q-wave than to non-Q-wave myocardial infarction.

Risk stratification of patients undergoing peripheral vascular revascularization by combined resting and dipyridamole echocardiography

Patients with advanced peripheral vascular disease have an increased cardiac morbidity and mortality. The aim of this study was to assess the predictive value of rest and stress echocardiography for perioperative and late cardiac events in 110 patients undergoing limb revascularization. All patients underwent preoperative clinical and echocardiographic evaluation at rest and by dipyridamole stress testing to assess cardiac risk. Patients with > or =3 clinical Eagle markers, low left ventricular ejection fraction at rest, or positive dipyridamole stress test results were considered at high cardiac risk. To record adverse cardiac events, all patients were monitored during and after surgery, and followed for at least 1 year after hospital discharge. Cardiac complications occurred in 10 patients (9.7%) perioperatively (2 fatal myocardial infarctions), and in 13 (13%) at 1-year follow-up (7 fatal myocardial infarctions). Echocardiographic evaluation was the best predictor of early (p <0.00003) and late (p <0.0003) cardiac complications. No patient with a negative dipyridamole stress test result and good left ventricular ejection fraction had cardiac complications, either postoperatively or during follow-up. Clinical evaluation does not appear sufficiently sensitive for predicting perioperative cardiac events, but was valuable in predicting late cardiac complications (p <0.0002). Our data show that echocardiographic evaluation of resting dysfunction and of the ischemic response to dipyridamole is a good predictor of perioperative cardiac risk, and is superior to generally available clinical data. Echocardiographic evaluation is useful in defining a low-risk group of patients who can safely undergo limb revascularization, whichever surgical procedure is proposed.

Cost-effective pharmacological prevention of acute coronary syndromes

The growing size of trials on primary and secondary prevention of acute coronary syndromes characterised by very broad inclusion criteria may seem logical to 'trialists', who reason that the the broader the inclusion criteria, the easier it is to recruit large numbers of patients in a short period of time and the more widely applicable are the results of the study. However, large trials with very broad inclusion criteria raise two grounds for concern for physicians. The first is that the broader the inclusion criteria for enrollment in a trial in order to prove a statistically significant benefit, the greater the heterogeneity of the study population which is likely to include both susceptible and non-susceptible patients to the tested treatment. The second is that this method of assessment rapidly increases the number of treatments that produce a statistically-significant improvement in prognosis within the same broad group of patients. On the contrary, the identification of potential responders to a specific treatment can provide a personalised form of medical care suited to the needs of each individual patient with an optimal cost-benefit ratio. This approach, however, represents a major challenge as it can only be based on the identification of homogeneous subgroups of patients with common risk factors for the development of acute coronary syndromes or of their recurrence. This challenge can only be overcome by a strong commitment in funding studies on the multiple causes of acute coronary syndromes.

Association of virulent Helicobacter pylori strains with ischemic heart disease

BACKGROUND

Previous studies have reported an association between chronic Helicobacter pylori infection and ischemic heart disease. However, it is not clear whether this association is really due to the virulence of the bacterium or is merely the result of confounding factors (in particular, age and social class).

METHODS AND RESULTS

We assessed the prevalence of infection by Helicobacter pylori and by strains bearing the cytotoxin-associated gene-A (CagA), a strong virulence factor, in 88 patients with ischemic heart disease (age, 57+/-8 years; 74 men) and in 88 age- and sex-matched controls (age, 57+/-8 years; 74 men) with similar social background. Prevalence of Helicobacter infection was significantly higher in patients than in controls (62% versus 40%; P=.004), with an odds ratio of 2.8 (95% CI, 1.3 to 7.4; P<.001) adjusted for age, sex, main cardiovascular risk factors, and social class. Patients with ischemic heart disease also had a higher prevalence of CagA-positive strains (43% versus 17%; P=.0002), with an adjusted odds ratio of 3.8 (95% CI, 1.6 to 9.1; P<.001). Conversely, prevalence of CagA-negative strains was similar in patients and controls (19% versus 23%), with an adjusted odds ratio of 0.8 (95% CI, 0.4 to 1.4).

CONCLUSIONS

The association between Helicobacter pylori and ischemic heart disease seems to be due to a higher prevalence of more virulent Helicobacter strains in patients. These results support the hypothesis that Helicobacter pylori may influence atherogenesis through low-grade, persistent inflammatory stimulation.

Management strategies for a better outcome in unstable coronary artery disease

Unstable coronary artery disease is a term encompassing both unstable angina and non-Q-wave (non-ST-segment elevation) myocardial infarction. Patients with these conditions are at risk of early progression to acute myocardial infarction and death. Thus, management of these conditions must aim to reduce long-term mortality and morbidity. Risk stratification is crucial for the identification of patients whose risk of early progression is high; they may require coronary angiography and (if suitable) either percutaneous transluminal coronary angioplasty or coronary artery bypass surgery. No single variable can accurately predict risk, but considerable data are emerging to show that biochemical markers of myocardial injury, such as troponin-T and troponin-I, are valuable in combination with electrocardiographic findings and clinical features. Routine early invasive procedures (coronary angiography with or without revascularization) have not yet been shown to have any significant advantage over conservative regimens for the majority of patients. Antiplatelet, anticoagulant, and anti-ischemic agents remain the mainstay of treatment in the acute phase. New agents, such as glycoprotein IIb/IIIa receptor inhibitors and low-molecular-weight heparins, as well as antithrombins and Factor Xa inhibitors add to the treatments currently available. Thrombolytic agents are contraindicated in the absence of ST-segment elevation. After clinical stabilization, ongoing assessment should include exercise testing for all patients who are able; other imaging techniques should be used for patients unable to exercise. A profile indicating a high risk of future events is an indication for elective angiography and consideration for revascularization.

[Clinical presentation of unstable angina may influence the formation of thrombin during spontaneous episodes of ischemia]

In order to evaluate whether different clinical presentations of unstable angina are associated with a different degree or pattern of activation of the hemostatic, fibrinolytic and inflammatory systems, we measured plasma levels of thrombin-antithrombin III, plasmin-alpha2- antiplasmin complexes and C-reactive protein, as markers of activation of coagulation, fibrinolysis and inflammation respectively, in two groups of patients: 7 patients with de novo unstable angina (Group 1) and 7 patients with destabilizing unstable angina (Group 2). Blood samples were taken on admission for measuring levels of C-reactive protein and during ischemic episodes at the onset of ECG changes and pain (0 min) and after 5, 15 and 60 min in order to assess the peak values of thrombin-antithrombin III and plasmin-alpha2-antiplasmin during the episode. Thrombin-antithrombin III levels in Group 1 were 1.8 microgram/l (0.3-4.15) at 0 min and increased to 17 micrograms/l (2.8-60) after 5 to 15 min (p = 0.013); conversely thrombin-antithrombin III levels in Group 2 were 2.15 microgram/l (1.4-3.8) at 0 min and raised to 4 micrograms/l (2-43) after 5 to 15 min (NS). No significant differences in both groups were observed in plasmin-alpha2-antiplasmin levels (Group 1:650 micrograms/l, ranged 492-956, at 0 min vs 670 microgram/l, range 415-977, at peak; Group 2: 480 micrograms/l, range 274-955, at 0 min vs 502 micrograms/l, range 304-1027, at peak; NS). Inversely, C-reactive protein levels on admission were 4 mg/dl (range 2-27) in Group 1, and 1 mg/dl (range 0.6-4) in Group 2 (p = 0.006). In conclusion, patients with de novo unstable angina have significantly enhanced thrombin (but not plasmin) production during spontaneous ischemic episodes than patients with destabilizing unstable angina. Furthermore, patients with de novo unstable angina have enhanced acute phase responses than patients with destabilizing unstable angina. Our data suggest that different pathogenetic mechanisms may be responsible for acute ischemic episodes in unstable angina and may explain different response to antithrombotic therapy in unstable angina patients.

Rationale and clinical evidence for the use of GP IIb/IIIa inhibitors in acute coronary syndromes

Platelet glycoprotein (GP) IIb/IIIa blockade has the potential to advance treatment of acute coronary syndromes, both as a primary pharmacologic approach and an adjunct to interventional treatment strategies. The benefits of GP IIb/IIIa inhibition with the chimeric monoclonal antibody abciximab in preventing ischemic complications of interventional treatment have been well defined in patients with unstable angina. In the future, major therapeutic applications for this class of agents may include the stabilization of patients with unstable angina and potentially as single medical therapy, as several recently completed trials have suggested. Evidence also is accumulating on the use of GP IIb/IIIa blockade as adjunctive therapy in fibrinolytic approaches to treatment of acute myocardial infarction. Several ongoing trials are evaluating the safety and efficacy of this novel strategy. This article reflects a distillation of the views and consensus regarding the prospective use of GP IIb/IIIa inhibitors in patients with acute coronary syndromes expressed by a group of international experts convened in Davos, Switzerland, February 16, 1997. This report attempts to review clinical progress to date, formulate recommendations, and map out potentially fruitful lines of inquiry for future investigation.

Rationale and clinical evidence for the use of GP IIb/IIIa inhibitors in acute coronary syndromes

Platelet glycoprotein (GP) IIb/IIIa blockade has the potential to advance treatment of acute coronary syndromes, both as a primary pharmacologic approach and an adjunct to interventional treatment strategies. The benefits of GP IIb/IIIa inhibition with the chimeric monoclonal antibody abciximab in preventing ischemic complications of interventional treatment have been well defined in patients with unstable angina. In the future, major therapeutic applications for this class of agents may include the stabilization of patients with unstable angina and potentially as single medical therapy, as several recently completed trials have suggested. Evidence also is accumulating on the use of GP IIb/IIIa blockade as adjunctive therapy in fibrinolytic approaches to treatment of acute myocardial infarction. Several ongoing trials are evaluating the safety and efficacy of this novel strategy. This article reflects a distillation of the views and consensus regarding the prospective use of GP IIb/IIIa inhibitors in patients with acute coronary syndromes expressed by a group of international experts convened in Davos, Switzerland, February 16, 1997. This report attempts to review clinical progress to date, formulate recommendations, and map out potentially fruitful lines of inquiry for future investigation.

[Tryptase levels are elevated during spontaneous ischemic episodes in unstable angina but not after the ergonovine test in variant angina]

Activated mast cells are present in human coronary atheromas, as well as in the adventitia of patients with variant angina, and may play an important role in plaque rupture and coronary vasomotion. To assess whether or not activation of mast cells is a primary event, we measured serum levels of tryptase, a specific marker of mast cell activation, in 8 patients with unstable angina during a spontaneous ischemic episode (Group 1) and in 5 patients with variant angina (Group 2) during ergonovine-induced coronary spasm. Blood samples were collected as soon as possible after the onset of pain and ECG changes (0 min), and after 5, 15 and 60 min. Tryptase levels in Group 1 were 0.13 U/l (range 0.017-0.44) at the onset of pain and significantly raised to 0.75 U/l (range 0.05-2.49) at 5 min, decreasing to 0.076 U/l (range 0.018-0.16) at 15 min and to 0.085 U/l (range 0.01-0.25) at 60 min (p = 0.035). Conversely, tryptase levels in Group 2 were 0.09 U/l (range 0.07-0.13) at 0 min, 0.11 U/l (range 0.07-0.22) at 5 min, 0.10 U/l (range 0.07-0.18) at 15 min, 0.11 U/l (range 0.07-0.17) at 60 min (NS). In conclusion, tryptase levels raise during spontaneous ischemic episodes in unstable angina, but not after ergonovine-provoked ischemia in variant angina, suggesting that a primary, yet unknown stimulus, may activate mast cells during some ischemic episodes in unstable angina.

The "warm-up" phenomenon occurs in patients with chronic stable angina but not in patients with syndrome X

Most patients with chronic stable angina show an improvement in ischemic threshold when a second exercise test is performed a few minutes after a first positive test. In this study we evaluated whether this "warm-up" phenomenon also occurs in patients with syndrome X. We performed 2 consecutive exercise tests in 14 patients with chronic stable angina and 11 patients with syndrome X. The second exercise test was performed after 10 minutes from the end of the first one, always after complete recovery to baseline of ST segment. In patients with stable angina, heart rate (108+/-18 vs 99+/-16 beats/min, p = 0.005), rate-pressure product (17,020+/-4,541 vs 15,215+/-3,734 beats/min x mm Hg, p = 0.028), and exercise time (587+/-297 vs 444+/-244 seconds, p = 0.002) at 1-mm ST depression were higher in the second test than in the first one and a significant improvement in these parameters during the second test was also observed at peak exercise. Conversely, in patients with syndrome X, there were no significant differences between the 2 tests in heart rate (128+/-18 vs 131+/-23 beats/min), rate-pressure product (19,922+/-5,153 vs 19,390+/-5,654 beats/min x mm Hg), and exercise time (592+/-243 vs 566+/-228 seconds) at 1-mm ST-segment depression. Similarly, in this group of patients, no significant differences in exercise variables between the 2 tests were observed at peak exercise. Thus, unlike patients with chronic stable angina, patients with syndrome X have no evidence of warm-up in response to repeated exercise testing.