Angiographic stenosis progression and coronary events in patients with 'stabilized' unstable angina

Impact of the Temporal Distribution of Coronary Artery Disease Progression on Subsequent Consequences in Patients with Acute Coronary Syndrome

The late consequences of acute coronary syndrome (ACS) have been underestimated. We hypothesized that the temporal distribution of the clinically silent coronary artery disease progression (CP) is associated with the subsequent consequences of ACS.We studied 243 patients (202 men, 64 ± 10 years) with ACS undergoing percutaneous coronary intervention (PCI) during initial hospitalization. All patients underwent serial coronary angiograms (CAGs) immediately before PCI and at 7 ± 3 and 60 ± 10 months after presentation. CP was defined as an increase ≥ 15% in stenosis severity of the lesion between 2 serial CAGs. The impact of CP between each 2 serial CAGs on subsequent major adverse cardiovascular and cerebrovascular events (MACCEs) after the final CAG was examined using multivariate Cox and propensity-matched analyses.During the median follow-up duration after the final CAG of 67 months, 76 MACCEs (31.3%) were observed. Multivariate Cox proportional hazards analysis revealed that CP between the first and second CAGs (hazard ratio [HR], 2.28; 95% confidence interval [CI], 1.32-3.94; P = 0.003) and CP between the second and final CAGs (HR, 1.96; 95% CI, 1.20-3.21; P = 0.008) were independently associated with a higher rate of MACCEs beyond the final CAG. Consistent results were obtained in the propensity score-matched analyses.CP in both the early (0-7 months) and late phases (7-60 months) were independently associated with subsequent clinical events. This may indicate the prognostic significance of persistent widespread coronary disease activity following presentation in patients with ACS undergoing PCI.

ST-segment category at acute presentation is associated with the time course of coronary artery disease progression in patients with acute coronary syndromes

BACKGROUND

Several studies have shown higher early mortality for ST-segment elevation acute coronary syndrome (STEACS), but late mortality remains consistently higher for non-ST-segment elevation acute coronary syndrome (NSTEACS). We hypothesized that ST-segment category at acute presentation is associated with the time course of coronary artery disease progression (CP) of nonculprit lesions in patients with acute coronary syndrome (ACS).

METHODS

A total of 226 patients (182 men, age 65 ± 10 years) with STEACS (n = 95) or NSTEACS (n = 131) who underwent percutaneous coronary intervention (PCI) during initial hospitalization were studied. All patients underwent serial coronary angiograms (CAGs) performed immediately before PCI and at 7 ± 3 months and 60 ± 10 months after presentation. CP was defined as an increase in stenosis severity >15% of a nonculprit lesion between 2 serial CAGs.

RESULTS

The rate of CP between the first and second CAGs did not differ by ST-segment category at acute presentation. Compared to STEACS, NSTEACS had a higher rate of CP between the second and final CAGs (27.4 vs. 42.7%, P = 0.018). Multivariate analysis showed that the independent predictors of CP between the second and final CAGs were NSTEACS (odds ratio 2.709, P = 0.003), estimated glomerular filtration rate <60 ml/min/1.73 m² (odds ratio 2.447, P = 0.015), and diabetes mellitus (odds ratio 2.135, P = 0.021).

CONCLUSIONS

Irrespective of conventional risk factors and angiographic findings, ST-segment category at initial presentation is associated with the persistency of widespread coronary disease activity following presentation in ACS patients undergoing PCI. This may partly explain the time-dependent differences in outcomes of patients with STEACS and NSTEACS.

Identification of vulnerable atherosclerotic plaques

There has been great interest in the possibility of identifying plaques that might be the site of future acute coronary events. These plaques are termed vulnerable and the majority are lipid-rich with an abundance of inflammatory cells and a thin fibrous cap. Several techniques developed to identify these plaques are in various stages of development and in the near future, one might employ a strategy to potentially identify and therapeutically modify such lesions during percutaneous intervention to avoid future acute events. Although this approach of identifying the vulnerable plaque seems promising, there are significant potential limitations. The natural history of a vulnerable plaque is unknown and clinical trials utilizing this strategy of identification and therapeutic intervention are lacking. Moreover, in any given patient, multiple vulnerable plaques are likely to be present. This article reviews some of the techniques for identifying a vulnerable plaque and discusses the potential advantages and limitations of this strategy.

Increased serum C1q-binding adiponectin complex to total-adiponectin ratio in men with multi-vessel coronary disease

BACKGROUND

Adiponectin plays a role as a positive contributor to the stabilization of atherosclerotic plaques. Circulating total adiponectin (Total-APN) levels associates with the number of coronary vessels in men with coronary artery disease (CAD). We recently reported that adiponectin binds to C1q in human blood, and serum C1q-binding adiponectin (C1q-APN) /Total-APN levels are associated with CAD in type 2 diabetic subjects. The present study investigated the relationship between circulating C1q-APN levels and the number of angiographic coronary artery vessel in male subjects.

METHODS

The study subjects were 53 male Japanese patients who underwent diagnostic coronary angiography. Blood total adiponectin (Total-APN), high-molecular weight adiponectin (HMW-APN), C1q-APN and C1q were measured by enzyme-linked immunosorbent assays.

RESULTS

Serum C1q-APN/Total-APN ratio significantly increased in subjects with single and multi-vessel coronary diseases (p = 0.029 for trend, the Kruskal-Wallis test). However, serum Total-APN, HMW-APN, C1q-APN and C1q levels did not correlate with number of diseased coronary vessels.

CONCLUSION

Serum C1q-APN/Total-APN ratio progressively increases in men with single and multi-vessel coronary disease.

TRIAL REGISTRATION

UMIN000002997.

Update on acute coronary syndromes: the pathologists' view

Although mortality rates from coronary heart disease in the western countries have declined in the last few decades, morbidity caused by this disease is increasing and a substantial number of patients still suffer acute coronary syndrome (ACS) and sudden cardiac death. Acute coronary syndrome occurs as a result of myocardial ischaemia and its manifestations include acute myocardial infarction and unstable angina. Culprit plaque morphology in these patients varies from thrombosis with or without coronary occlusion to sudden narrowing of the lumen from intraplaque haemorrhage. The coronary artery plaque morphologies primarily responsible for thrombosis are plaque rupture, and plaque erosion, with plaque rupture being the most common cause of acute myocardial infarction, especially in men. Autopsy data demonstrate that women <50 years of age more frequently have erosion, whereas in older women, the frequency of rupture increases with each decade. Ruptured plaques are associated with positive (expansive) remodelling and characterized by a large necrotic core and a thin fibrous cap that is disrupted and infiltrated by foamy macrophages. Plaque erosion lesions are often negatively remodelled with the plaque itself being rich in smooth muscle cells and proteoglycans with minimal to absence of inflammation. Plaque haemorrhage may expand the plaque rapidly, leading to the development of unstable angina. Plaque haemorrhage may occur from plaque rupture (fissure) or from neovascularization (angiogenesis). Atherosclerosis is now recognized as an inflammatory disease with macrophages and T-lymphocytes playing a dominant role. Recently at least two subtypes of macrophages have been identified. M1 is a pro-inflammatory macrophage while M2 seems to play a role in dampening inflammation and promoting tissue repair. A third type of macrophage, termed by us as haemoglobin associated macrophage or M(Hb) which is observed at site of haemorrhage also can be demonstrated in human atherosclerosis. In order to further our understanding of the specific biological events which trigger plaque instability and as well as to monitor the effects of novel anti-atherosclerotic therapies newer imaging modalities in vivo are needed.

Serum chitotriosidase activity, a marker of activated macrophages, predicts new cardiovascular events independently of C-reactive protein

BACKGROUND

C-reactive protein (CRP) is a well-established inflammation marker associated with cardiovascular risk. However, its relationship with chitotriosidase activity, a novel marker of activated macrophages highly expressed in human atherosclerotic plaques, is unknown. Therefore, we sought to determine if serum chitotriosidase activity predicts the risk of new coronary events, and to analyze its relationship with CRP.

METHODS

Chitotriosidase activity and genotype, and high-sensitivity CRP were measured at baseline in 133 middle-aged men with stable coronary heart disease, who were followed for the occurrence of cardiovascular morbidity and mortality for a mean of 4 years. We studied the value of these proteins in predicting the risk of new cardiovascular events.

RESULTS

Serum chitotriosidase activity was higher in the group of subjects with a prespecified major event (nonfatal myocardial infarction, nonfatal ischemic stroke, coronary revascularization procedures and death from cardiovascular causes) than in the group of subjects without event, 116 +/- 30.9 nmol/ml x h versus 74.2 +/- 5.69 nmol/ml x h, respectively (p = 0.042). The baseline values of chitotriosidase activity and CRP did not correlate (R = 0.104, p = 0.266), but both parameters were related to a reduction of event-free survival in the Cox regression analysis, with relative risks of 2.61 (p = 0.060) and 2.56 (p = 0.019), respectively. Chitotriosidase activity seems to be a better marker for new events occurring after 2 years of follow-up than in the first 2 years. Both markers had similar predictive values, and their sensitivity (64%) and negative predictive value (84%) were improved when combined.

CONCLUSIONS

Our results suggest that serum chitotriosidase activity predicts the risk of new cardiovascular events in the following 4 years. This new cardiovascular risk marker is independent of CRP and, when combined, the prediction of the risk of new cardiovascular events and the identification of a lower risk group seem to improve.

Silent myocardial ischaemia: clinical relevance and treatment

Transient myocardial ischaemia in the absence of chest pain ('silent ischaemia') commonly occurs in patients with coronary artery disease (CAD) and has important prognostic implications. However, doubts exist as to whether and how silent ischaemia should be managed. In the present article we review current knowledge regarding silent ischaemia and the role of recently developed drugs that may be effective to control its occurrence. Since the description in the 1770s of the syndrome of 'angina pectoris' by William Heberden, the importance of chest pain for the diagnosis of CAD has remained un-abated. However, several decades ago it became apparent that both myocardial infarctions and transient episodes of myocardial ischaemia could occur in the absence of chest pain. Indeed, a large proportion of patients with CAD have both silent and painful myocardial ischaemia as a manifestation of CAD. Whether the presence of asymptomatic ischaemic electrocardiographic changes in patients with CAD has prognostic importance and whether it needs medical or surgical treatment has been a matter of speculation for several decades.

Rapid disappearance of an endothelial ulceration in the left main coronary artery

A case is presented of a 65-year-old male who presented with an acute anterior wall myocardial infarction. An initial coronary angiogram demonstrated an ulcerated atherosclerotic plaque in the left main coronary artery. After 48 h of aggressive medical therapy including a 2b3a glycoprotein blocking agent, repeat angiography demonstrated resolution of the ulcerated plaque. The process of atherosclerotic plaque rupture is of dynamic nature.

Plasma adiponectin levels are associated with coronary lesion complexity in men with coronary artery disease

OBJECTIVES

We sought to assess whether plasma adiponectin levels correlate with angiographic coronary lesion complexity in patients with coronary artery disease (CAD).

BACKGROUND

Metabolic disorders, including diabetes mellitus and metabolic syndrome, are important risk factors for acute cardiovascular events, and adiponectin is a key molecule of metabolic disorders, with anti-atherogenic properties. Low plasma adiponectin levels are associated with CAD and future incidence of myocardial infarction. The involvement of adiponectin in coronary plaque vulnerability, which may be reflected by angiographic complex lesions, remains to be elucidated.

METHODS

We measured plasma adiponectin levels in 207 men (152 with stable CAD and 55 with acute coronary syndromes [ACS]). Coronary lesions were classified as of simple or complex appearance.

RESULTS

Plasma adiponectin levels were significantly lower in stable CAD patients with complex coronary lesions (n = 60) than in those with simple lesions (n = 92) (4.14 [range 2.95 to 6.02] vs. 5.27 [range 3.67 to 8.12] microg/ml, p = 0.006). Multiple logistic regression analysis demonstrated that adiponectin level was independently associated with complex lesions (odds ratio 0.514, 95% confidence interval 0.278 to 0.951; p = 0.034). Polytomous logistic regression revealed that adiponectin correlated independently with both single and multiple complex lesions. Among patients with ACS, who had lower adiponectin levels than stable CAD patients, those with multiple complex lesions had significantly lower adiponectin than those with a single complex lesion (3.26 [range 2.26 to 4.46] vs. 4.21 [range 3.36 to 5.41] microg/ml, p = 0.032).

CONCLUSIONS

Plasma adiponectin levels are significantly associated with coronary lesion complexity in men with CAD. Low adiponectin levels may contribute to coronary plaque vulnerability.

Plasma C-Reactive Protein and Lipoprotein Levels, and Progression of Coronary Artery Disease after Myocardial Infarction Treated with Thrombolysis

BACKGROUND

There is a paucity of studies using quantitative coronary angiography (QCA) to determine progression of coronary artery disease (CAD) after an acute coronary event. Furthermore, despite a great interest in effects of inflammation and 'early' lipid lowering therapy, no data have been published on the role of plasma C-reactive protein (CRP) and lipoprotein levels in CAD progression after myocardial infarction.

METHODS

Seventy-two patients with myocardial infarction treated with thrombolysis, but not with statins, were investigated with QCA during admission and after 6 months. Plasma CRP concentrations were measured by a high sensitive method 2 days after the acute event, and plasma high-sensitive CRP and lipoprotein levels were determined 3 months after myocardial infarction.

RESULTS

Overall, there was no significant progression of CAD, but when stenoses were grouped into those reducing the lumen diameter greater or less than 50%, progression was seen in stenoses originally <50%, whereas regression was seen in stenoses >50%. No consistent associations were seen between plasma CRP, lipoprotein lipid or lipoprotein(a) levels and CAD.

CONCLUSIONS

Progression of stenoses <50% might be of clinical importance since these stenoses are more prone to rupture. Furthermore, the lack of associations between change in minimum lumen diameter and plasma CRP and lipoprotein concentrations suggests that positive effects on CAD progression of early treatment with anti-inflammatory or lipid-lowering drug therapy may not be expected in this subset of patients.

T helper cell related interleukins and the angiographic morphology in unstable angina

Angiographically visible complex lesions, associated with disrupted plaques and intraluminal thrombus, are more common in unstable angina (UA). The aim of our study was to evaluate the relationship between the complex lesions and the T helper cells related Interleukins (IL). We analyzed the concentrations of IL-10, IL-12, IL-18 using ELISA and that of hsCRP using Latex particle enhanced Immunoturbidimetry in 50 patients of UA. Thirty-one of these patients had complex lesions and 19 had simple lesions as visible during coronary angiography. We further compared them with 30 control subjects having no evidence of coronary artery diseases. The levels of IL-12 in patients having complex lesions tended to be higher than in those having simple lesions and levels of IL-10 tended to be lower in the former than the latter, but the differences were not statistically significant. The patients with complex lesions showed significantly higher concentrations of IL-18 as compared to those having simple lesions. Furthermore, IL-18 was found to be independent predictor for the complex lesion morphology in UA patients. These findings suggest that disrupted plaques and intraluminal thrombus, angiographically visible as complex lesions are associated with increased concentrations of T helper 1 cell related interleukins, mainly IL-18, and IL-18 being a possible bio-marker for risk stratification in UA.

Markers of inflammation and multiple complex stenoses (pancoronary plaque vulnerability) in patients with non-ST segment elevation acute coronary syndromes

OBJECTIVE

To assess the relation between markers of inflammation and the presence of multiple vulnerable plaques in patients with non-ST segment elevation acute coronary syndromes.

DESIGN

Prospective cohort study of 55 patients with non-ST segment elevation acute coronary syndromes and angiographically documented coronary disease. Blood samples were obtained at study entry for the assessment of high sensitivity C reactive protein (CRP), neopterin, and neutrophil count. Coronary stenoses were assessed by quantitative computerised angiography and classified as "complex" (irregular borders, ulceration, or filling defects) or "smooth" (absence of complex features). Extent of disease was also assessed by a validated angiographic score.

RESULTS

Neutrophil count (r = 0.36, p = 0.007), CRP concentration (r = 0.33, p = 0.02), and neopterin concentration (r = 0.45, p < 0.001) correlated with the number of complex stenoses. Patients with multiple (three or more) complex stenoses, but not patients with multiple smooth lesions, had a higher neutrophil count (5.9 (1.4) x 10(9)/l v 4.8 (1.4) x 10(9)/l, p = 0.02), CRP concentration (log transformed) (1.08 (0.63) v 0.6 (0.6), p = 0.03), and neopterin concentration (log transformed) (0.94 (0.18) v 0.79 (0.15), p = 0.002). Multiple regression analysis showed that neopterin concentration (B = 4.8, 95% confidence interval (CI) 1.9 to 7.7, p = 0.002) and extent of coronary artery disease (B = 0.6, 95% CI 0.03 to 1.2, p = 0.04) were independently associated with the number of complex stenoses.

CONCLUSIONS

Acute inflammatory markers such as high neutrophil count, CRP concentration, and neopterin concentration correlate with the presence of multiple angiographically complex coronary stenoses. Neopterin concentration was a stronger predictor of multiple complex plaques than were neutrophil count and CRP concentration. These findings suggest that a relation exists between inflammation and pancoronary plaque vulnerability.

Multiple complex stenoses, high neutrophil count and C-reactive protein levels in patients with chronic stable angina

Inflammation plays an important role in atherosclerosis and the genesis of acute coronary syndromes, i.e., atheromatous plaque disruption. Neutrophil count and C-reactive protein (CRP) levels are markers of ongoing inflammation and predictors of cardiovascular risk. We sought to assess whether these inflammatory markers are associated with the presence of multiple complex stenoses in patients with chronic stable angina.

METHODS AND RESULTS

We assessed 150 patients with chronic stable angina, 121 with significant coronary artery stenosis (> or =50% diameter reduction) and 29 without. CRP levels and neutrophil count were assessed at study entry. Stenoses were classified as "complex" (irregular or scalloped borders, ulceration or filling defects) or "smooth" (absence of complex features). Eighty-eight percent of the complex lesions were of type C according to AHA/ACC classification whereas the rest were type B. Patients with > or =3 complex lesions were considered to have multiple complex stenoses. Extent of coronary artery disease was assessed using a validated score. Baseline neutrophil count (4.39 x 10(9) L (-1) +/- 28 versus 3.82 x 10(9) L (-1) +/- 0.77; P = 0.004) and CRP levels (2.15 mg/L (4.6-1) versus 0.39 mg/L (0.69-0.23); P < 0.0001) were higher in patients with significant stenoses compared to patients without. No association was found between disease extent and CRP levels or neutrophil count. Neutrophil count, however (but not CRP) correlated with stenosis complexity (r = 0.28; P = 0.002 ) and was also an independent predictor of the presence of multiple complex stenoses (OR: 4.05; CI 95% (1.9-10.4); P = 0.038).

CONCLUSIONS

CRP levels and neutrophil count are higher in angina patients with coronary stenoses compared to those without. Neutrophil count, but not CRP levels, correlates with angiographic stenosis complexity.

Independent contribution of plaque complexity to myocardial ischemia during dobutamine stress echocardiography

The influence of complex plaque morphology on the extent of demand-induced ischemia in unselected patients is not well defined. We sought to investigate the functional significance of lesion morphology in patients who underwent coronary angiography and dobutamine stress echocardiography (DSE). Angiography and DSE were performed within a 6-month period (mean 1 +/- 1 month) in 196 patients. Angiographic assessments involved quantification of stenosis severity, assessment of the extent of jeopardized myocardium, and categorization of plaque morphology according to the Ambrose classification. DSE was interpreted by separate investigators with respect to wall motion score index (WMSI) and number of coronary territories involved. A general linear model was constructed to assess the independent contribution of patient characteristics and angiographic and DSE results with respect to extent of ischemic myocardium. Complex lesion morphology was seen in 62 patients (32%). Patients with complex lesions were more likely to have had prior myocardial infarction (p <0.001) and be current smokers (p = 0.03). During angiography, they exhibited a trend toward a greater number of diseased vessels, had a greater coronary jeopardy score (p <0.001) and more frequent collateral flow (p = 0.03). During echocardiography, patients had a higher stress WMSI (p <0.001) and were more likely to show ischemia in all 3 arterial territories (p <0.01). On multivariate regression, the coronary artery jeopardy score and the presence of complex plaque morphology were independent predictors of the extent of ischemic myocardium (R(2) = 34%, p <0.001). Thus, patients with complex plaque morphology are older, more likely to smoke, and more likely to have had prior myocardial infarction. They exhibit more extensive disease with higher coronary jeopardy scores and a higher resting and peak stress WMSI. Despite these differences, complex plaque morphology remains an independent predictor of the extent of ischemia during stress.

[Importance of severe lesions left untreated in patients with acute coronary syndromes and angioplasty of the culprit lesion]

INTRODUCTION AND OBJECTIVES

Patients with acute coronary syndromes may have significantly stenotic nonculprit lesions that do not show complex lesion morphology. We investigated whether these lesions were prone to become unstable since they exist within a prothrombotic and inflammatory systemic milieu.

PATIENTS AND METHOD

We evaluated the clinical course of 150 patients after successful angioplasty of a culprit lesion: 75 patients with a severely stenotic but uncomplicated nonculprit lesion (group A) and 75 patients without these lesions (group B).

RESULTS

In group A, 1 patient (1.3%) required angioplasty of an initially nonculprit lesion, and in group B, 2 patients (2.6%) died in cardiogenic shock. After 1 year of follow-up, in group A, 4 patients (5.3%) died (cardiac deaths), 1 patient (1.3%) had a myocardial infarction, and 10 patients (13.3%) underwent a repeat revascularization procedure, which in 6 cases (8%) was angioplasty of an initially nonculprit lesion. In all 6 patients with angioplasty of the initially nonculprit lesion, revascularization was done within the first 4 months and was indicated for unstable angina. In group B, 1 patient (1.3%) died (noncardiac death) and 2 patients (2.6%) underwent a repeat revascularization procedure because of restenosis. Survival curves were significantly different between both groups. Belonging to group A was the only independent predictor for events, and within this group location of the lesion in the left anterior descending artery was the main predictor.

CONCLUSIONS

The presence of nonculprit lesions of uncomplicated morphology at the time of a percutaneous revascularization procedure for a culprit lesion in patients with acute coronary syndrome is a short- and middle-term predictor of a moderate rate of recurrent events when these initially innocuous lesions become unstable.

Neopterin levels in patients with coronary artery disease are independent of Chlamydia pneumoniae seropositivity

BACKGROUND

Chronic infection with Chlamydia pneumoniae (Cpn) has been associated with atherosclerotic cardiovascular disease in sero-epidemiological, pathological and animal-model studies. Inflammation and immune activation has been proposed as the pathophysiological link between chronic infection and atherosclerosis. The aim of this study was to assess whether Cpn seropositivity is associated with serum neopterin concentrations, a marker of macrophage activation, in patients with stable and unstable angina pectoris.

METHODS

We examined 100 patients with angiographically documented coronary artery disease: 60 patients had chronic stable angina and 40 had Braunwald class III unstable angina. Neopterin concentrations were measured with a commercially available immunoassay. Cpn titres were measured with a microimmunofluorescence (MIF) assay.

RESULTS

Neopterin concentrations were significantly higher in patients with unstable angina compared to those with chronic stable angina (6.30 [4.85-8.80] nmol/L vs 4.95 [3.35-7.05] nmol/L, P =.004), even after adjustment for variables that were significantly different between the 2 groups on univariate analysis. In contrast, the prevalence of positive Cpn serology did not differ significantly between the 2 angina patient groups (65% v 58%, P =.50). Neopterin levels were similar between Cpn-negative and Cpn-positive patients (P =.40) in both stable and unstable angina groups.

CONCLUSIONS

Patients with unstable angina had higher neopterin concentrations than patients with chronic stable angina, probably reflecting the higher degree of immune activation in acute coronary syndromes. Neopterin levels, however, were independent of Cpn serostatus when combining both stable and unstable angina patients. Thus, immune activation in patients with acute coronary syndromes appears to be unrelated to Cpn seropositivity.

Plaque blush, branch location, and calcification are angiographic predictors of progression of mild to moderate coronary stenoses

BACKGROUND

Angiographic predictors of plaque progression are weak and few: length, irregular surface, turbulence, low shear, and (in some studies) eccentricity and calcification. Having noted plaques that briefly retained dye after angiography, we interpreted these as plaques with a fissured surface or neovascularization and hypothesized that progression would be predicted by "plaque blush."

METHODS

Plaques (<50% diameter stenosis) in 68 pairs of angiograms, 5.6 +/- 4.8 months apart, were reviewed by 2 blinded observers. The presence of plaque blush, calcification, clot (mobile defect), eccentricity, and a branch point location were compared between progressing (> or =20% stenosis increase) and nonprogressing plaques.

RESULTS

Sixteen lesions in 15 patients progressed from 29% +/- 13% to 68% +/- 14% over a period of 8.1 +/- 7.9 months. Patients with and without progression were similar in sex, age, congestive heart disease risk factors, medications, interval between angiograms, clinical presentation, and initial stenosis severity. By logistic regression, plaque blush (BL) (P =.002), calcification (CA) (P =.024), and a branch (BR) point location (P =.001) predicted plaque progression. The odds ratio for plaque progression (ORp) was calculated as ORp = e(2.5 x BL + 1.8 x CA + 2.6 x BR). Using an ORp of 1/3, the model has 81% sensitivity and 77% specificity. A second analysis in which each progressive lesion was compared with proximal and distal lesions and with one in a different coronary artery yielded similar results.

CONCLUSIONS

In mild to moderate coronary stenoses, studied retrospectively, plaque blush (a new sign) and a branch point location were strong predictors of plaque progression, whereas calcification was a weak predictor of progression.

Do clinical and angiographic parameters predict failure of medical therapy in patients suitable for coronary angioplasty?

AIMS

Recent studies have suggested that patients with coronary disease suitable for angioplasty have an equally good outcome with medical therapy if clinically stable. Complex lesion morphology may predict acute events without intervention and stenosis severity influences the degree of collateralisation. This study was designed to assess the influence of these factors on clinical outcome.

METHODS AND RESULTS

A retrospective review of patients suitable for angioplasty who were randomised to initial medical therapy as part of a multicentre study. Angiograms were reviewed for lesion characteristics, TIMI flow grade, and degree of collateralisation. Angiograms were available on 79 patients (13 female, 66 male). Mean age was 54.8 years (range 43-68) in the group crossing-over to revascularisation, and 58.4 (range 37-78) in the group who did not (P=ns). Seventeen patients crossed-over (two to CABG, 15 to PTCA) at 5.4 months (range 0-10) after initial angiography. Disease progression had occurred in 10/17 patients (58.8%), three of whom developed a new occlusion. Collateralisation was more likely in smokers, independent of lesion severity (P<0.05). Time to cross-over was not influenced by progression of disease. Crossing-over was not affected by age, diabetic status, cholesterol level, vessel involved, lesion severity, TIMI flow, lesion morphology, collateralisation, or the number of vessels diseased, but was more likely in females (P<0.05).

CONCLUSION

This group of patients generally does well with medical therapy. Whilst the numbers are relatively small, there does not appear to be any reliable prospective marker, including the presence of spontaneous collateral channels on diagnostic angiography, to indicate which patients will fail medical therapy and require revascularisation.

Multifocal coronary plaque instability

Recent observations document that many patients with acute coronary syndromes harbor multiple complex plaques by angiography, which correlate with multiple plaque ruptures and clots at necropsy. Multifocal plaque instability is evident not only in coronary vessels but also in peripheral vessels where peripheral and coronary plaque instability may exist concomitantly. These observations support the concept that plaque instability is not merely a local vascular accident but instead reflects more systemic pathophysiological processes with potential to destabilize atherosclerotic plaques throughout the cardiovascular system.

The exercise test that indicates a low risk of events. Differences in prognostic significance between patients with chronic stable angina and patients with unstable angina

OBJECTIVES

The objective of this prospective study was to determine the differences in the prognostic significance of an exercise test (ET) that indicates a low risk of events (low-risk exercise test [LRET]) between patients with unstable angina (UA) and those with chronic stable angina (CSA).

BACKGROUND

It is not known whether the prognostic significance of an LRET is influenced by the disease; that is the reason for performing exercise testing.

METHODS

All patients not presenting with high-risk criteria were submitted to a prognostic ET. The ET was performed by patients with CSA and patients with primary UA stabilized with medical therapy. Medical therapy was planned for all patients. A combined end point was defined as cardiac death, nonfatal acute myocardial infarction or hospital admission for UA. Multivariate analysis was performed to determine the independent predictors of events.

RESULTS

Low-risk criteria were fulfilled by 105 patients with UA and 86 patients with CSA. The mean follow-up time was 347 +/- 229 days. The event rate was higher in the UA group than in the CSA group (28% vs. 9%, p = 0.001). The CSA group showed worse ET results. Performance of ET by patients with UA was the principal predictor of events (odds ratio 4.2, p = 0.0005).

CONCLUSIONS

Among patients who underwent an LRET, those with UA had a rate of events significantly higher than that of patients with CSA, despite the worse results of ET in patients with CSA.

Short- and long-term prognostic value of cardiac troponin I and dobutamine echocardiography in patients with stabilized acute coronary syndromes

BACKGROUND

This study investigated the short- and long-term prognostic values of cardiac troponin I (cTnI) and dobutamine echocardiography (DE) in patients with acute coronary syndrome (ACS) who stabilized after medical treatment.

METHODS AND RESULTS

171 consecutive patients of ACS accepted blood sampling for cTnI at the emergency department and DE at 4.9+/-0.6 days after admission. The prognostic values of cTnI, DE, and combined cTnI and DE were separately investigated at follow up periods of 30 days, 1 year and 3 years for hard events (cardiac death and non-fatal myocardial infarction) and all spontaneous events. CTnI was elevated in 55 (32%) patients and DE was positive in 114 (67%) patients. Elevated cTnI with positive DE were found in 44 (26%) patients. Within 30 days, the combination of elevated cTnI and positive DE provided more accurate prognostic information than each test result alone, and was the only independent predictor for both hard (p=0.014) and all events (p=0.012). After 1 year, cTnI alone had no prognostic value. The combination of an elevated cTnI level and a positive DE only had a prognostic value for all events (p=0.015). However, DE was an independent predictor for both hard (p=0.006) and all events (p=0.002). Neither cTnI alone nor cTnI combined with DE had a significant 3-year prognostic value. However, DE maintained its prognostic value and was still an independent predictor after 3 years for both hard (p=0.024) and all events (p=0.004).

CONCLUSIONS

For patients with stabilized ACS, the diagnostic finding of elevated cTnI combined with a positive DE has a better short-term prognostic value than each test alone. However, DE alone has a better long-term prognostic value.

Going from immutable to mutable atherosclerotic plaques

Atherosclerotic coronary disease develops over several decades and was once thought to be an inevitable, irreversible consequence of aging. Atherogenesis is an inflammatory response that occurs after injury to the endothelium. Thrombosis, because of either endothelial erosion or plaque disruption, precipitates acute coronary events. Effective lipid lowering with statins has consistently and significantly decreased the risk that acute ischemic events will occur. The beneficial effects of statins likely result not only from their lipid-lowering effects but also from mechanisms that influence plaque behavior. Atherosclerotic plaques are not immutable; rather, their structure and composition can be altered by therapeutic modification. Ample evidence from clinical trials supports statin treatment in patients with stable coronary disease. Results of recent clinical trials support early treatment of high-risk patients with unstable coronary disease; early and aggressive statin treatment resulted in fewer recurrent ischemic events in patients with an acute coronary syndrome. Additional studies are needed to confirm the benefit of early statin treatment in patients with unstable coronary disease and to elucidate the reasons for the occurrence of events in treated patients. Research is also necessary to clarify the role of other lipids, as well as nonlipid risk factors, in the occurrence of acute ischemic events.

Non-invasive prediction of angiographic progression of coronary artery disease by dipyridamole-stress echocardiography

BACKGROUND

Coronary angiography is the currently accepted standard means for assessing progression of coronary artery disease. A dipyridamole-echocardiography test (DET) might provide an alternative non-invasive functional imaging method for this purpose.

OBJECTIVE

To assess whether variations in results of serial DET match variations in angiographic assessments of coronary artery disease.

METHODS

From the Pisa Institute of Clinical Physiology stress-echocardiography data bank (1983-1998), we selected 60 patients satisfying the inclusion criteria of coronary angiography and DET having each been performed and interpreted twice independently and within 1 week. The second angiographic and stress-echocardiographic assessment was performed 45+/-31 months after the initial one. Angiographic progressors were defined a priori as patients with any progression of stenosis to occlusion and those with any stenosis > 30% with > 20% progression of stenosis measured by visual and quantitative coronary angiography. Stress-echocardiography progressors were defined as those patients who had previously had a negative test of a test having a positive result and those patients who had positive results of tests both in initial testing and in a second session of testing with the latter having a peak wall-motion-score index > 0.12 (on a scale of 1, normal to 4, dyskinetic in a 16-segment model) larger than the former.

RESULTS

Of the 60 patients, 44 were angiographic 'progressors' and 16 were 'non progressors'. Stress-echocardiographic responses were concordant with angiographic identification for 39 of 44 progressors and 15 of 16 non-progressors, with an overall concordance of 90%.

CONCLUSIONS

Measurement of dipyridamole-stress-echocardiographic response allows one to separate angiographic progressors and non-progressors efficiently, simply by taking into account the presence, extent and severity of stress-induced abnormalities of wall motion.

Unstable angina pectoris and non-Q-wave myocardial infarction

Unstable angina pectoris and non-Q-wave myocardial infarction are clinical syndromes that share many pathophysiologic and clinical features. In the spectrum of coronary artery disease, these syndromes lie between chronic stable angina and Q-wave myocardial infarction. Although both conditions are associated with significant morbidity and mortality, patients presenting with these syndromes can be further risk stratified into higher and lower risk based on a number of readily available clinical features and biochemical parameters. Such risk stratification can allow for more tailored treatment and better resource allocation. Although routine early coronary angiography and revascularization has not been shown to be superior to conservative management, certain high-risk patients may benefit from a more aggressive strategy. Medical therapy with the use of antiplatelet, anticoagulant, and antiischemic agents remains the cornerstone of emergent treatment for patients presenting with these syndromes. The recent demonstration of a reduction in both morbidity and mortality with the glycoprotein IIb/IIIa antagonists has further expanded the armamentarium of available agents. Following initial stabilization, risk stratification with stress testing can help identify patients with a large residual ischemic burden who may benefit from coronary angiography with revascularization if feasible.

Long-term outcome of coronary balloon angioplasty in diabetic patients

Diabetes is recognised to increase morbidity and mortality after coronary revascularization. We compared clinical outcomes in mean 5-year-long follow-up of coronary balloon angioplasty in diabetic and non-diabetic patients. We studied 621 patients undergoing elective angioplasty from 1987 to 1996. There were 60 (9.7%) patients with diabetes who were compared with 561 non-diabetic patients. Diabetics were older, more often obese, less frequently were current smokers, and less frequently had hypercholesterolaemia. Diabetic patients in comparison with non-diabetics had lower ejection fraction and more frequently had angioplasty of complex (B2 or C) lesions, but there were no differences between both groups in the other clinical and angiographic risk factors. Clinical success of angioplasty, as well as complications rate were similar in both groups. In follow-up restenosis occurred more frequently in diabetics (46.3 vs. 32.2%, P=0.03), resulting in significantly higher re-intervention rate (50.0 vs. 35.4%, P=0.03). Especially diabetic patients were more frequently referred to CABG (20.4 vs. 9. 9%, P=0.02). There were no significant differences in deaths (1.9 vs. 2.8%) and myocardial infarction (3.7 vs. 4.4%). Diabetics presented worse CCS status at the end of observation (Class 0 and I - 61.1 vs. 74.4%, P=0.037). Angioplasty proved to be a safe procedure in diabetic patients. Despite higher restenosis and re-intervention rate in diabetics, mortality as well as myocardial infarction rate was the same in both groups during mean 5-year follow-up.

Multiple complex coronary plaques in patients with acute myocardial infarction

BACKGROUND

Acute myocardial infarction is believed to be caused by rupture of an unstable coronary-artery plaque that appears as a single lesion on angiography. However, plaque instability might be caused by pathophysiologic processes, such as inflammation, that exert adverse effects throughout the coronary vasculature and that therefore result in multiple unstable lesions.

METHODS

To document the presence of multiple unstable plaques in patients with acute myocardial infarction and determine their influence on outcome, we analyzed angiograms from 253 patients for complex coronary plaques characterized by thrombus, ulceration, plaque irregularity, and impaired flow.

RESULTS

Single complex coronary plaques were identified in 153 patients (60.5 percent) and multiple complex plaques in the other 100 patients (39.5 percent). As compared with patients with single complex plaques, those with multiple complex plaques were less likely to undergo primary angioplasty (86.0 percent vs. 94.8 percent, P = 0.03) and more commonly required urgent bypass surgery (27.0 percent vs. 5.2 percent, P < or = 0.001). During the year after myocardial infarction, the presence of multiple complex plaques was associated with an increased incidence of recurrent acute coronary syndromes (19.0 percent vs. 2.6 percent, P < or = 0.001); repeated angioplasty (32.0 percent vs. 12.4 percent, P < or = 0.001), particularly of non-infarct-related lesions (17.0 percent vs. 4.6 percent, P < or = 0.001); and coronary-artery bypass graft surgery (35.0 percent vs. 11.1 percent, P < or = 0.001).

CONCLUSIONS

Patients with acute myocardial infarction may harbor multiple complex coronary plaques that are associated with adverse clinical outcomes. Plaque instability may be due to a widespread process throughout the coronary vessels, which may have implications for the management of acute ischemic heart disease.

Serum neopterin and complex stenosis morphology in patients with unstable angina

OBJECTIVES

We sought to assess the relation between serum neopterin concentration and complex coronary artery stenosis in patients with unstable angina.

BACKGROUND

Monocyte activation is associated with acute atheromatous plaque disruption and acute coronary syndromes. Angiographically demonstrated complex coronary stenosis is often an expression of plaque disruption. Increased serum concentration of neopterin, a pterydine derivative secreted by macrophages after stimulation by interferon-gamma, has been observed in patients with acute coronary syndromes as compared with control subjects and patients with stable angina pectoris.

METHODS

We studied 50 patients with unstable angina (32 men) who underwent coronary angiography after hospital admission. All coronary stenoses with > or =30% diameter reduction were assessed and classified as "complex" (irregular or scalloped borders, ulceration or filling defects suggesting thrombi) or "smooth" (absence of complex features). Serum neopterin levels were assessed within 24 h of hospital admission using a commercially available immunoassay (enzyme-linked immunosorbent assay kit, IBL, Hamburg, Germany).

RESULTS

Thirty-nine patients were classified in Braunwald class IIIb, four in class IIb and seven in class Ib. The number of complex lesions per patient was 2.6+/-1.8 (mean +/- SD). The mean neopterin concentration was 7.76+/-3.62 nmol/liter. A significant correlation was observed between neopterin serum concentration and the presence of complex coronary stenoses (r = 0.35, p = 0.015). Multiple regression analysis showed that serum neopterin (p < 0.0001) was independently associated with the number of complex lesions. Other variables associated with complex lesions were the number of vessels with > or =75% stenosis (p < 0.0001), plasma creatinine (p = 0.003), triglycerides (p = 0.014) and a history of unstable angina (p = 0.032).

CONCLUSIONS

Serum neopterin concentration is associated with the presence of angiographically demonstrated complex lesions in patients with unstable angina and may represent a marker of coronary disease activity.

Early-invasive or early-conservative management of patients with unstable angina or non-Q-wave myocardial infarction

The optimal therapy for non-ST-segment-elevation acute coronary syndromes is the subject of considerable debate: is early catheterization and revascularization (early-invasive strategy) or continued medical therapy unless symptoms are refractory (early-conservative strategy) best? Although several clinical trials have sought to answer this question, the methodologies they employed have been widely criticized, and no consensus has been reached. The new antiplatelet therapies have proved beneficial for primary medical management and as adjuncts to percutaneous interventions. It is not yet clear, however, whether use of these therapies will preferentially benefit one of the treatment strategies.

Unstable angina and non-Q wave myocardial infarction: does the clinical diagnosis have therapeutic implications?

OBJECTIVES

The goal of this review is to reevaluate the unstable coronary syndromes in the setting of new therapies and biochemical markers.

BACKGROUND

Patients with acute coronary syndromes comprise a large subset of many cardiology practices. Patients with unstable angina (UA) and non-Q wave myocardial infarction (NQMI) may sustain a small amount of myocardial loss but have significant amounts of viable, yet ischemic, myocardium, placing them at high risk for future cardiac events. In the past, enzyme differentiation of NQMI from UA was considered important to assess prognosis and direct therapy.

METHODS

Manuscripts published in peer-reviewed journals over the past three decades were reviewed and selected for this review. Recent abstracts were also considered and cited where appropriate.

RESULTS

In the late 1990's, although UA and NQMI remain parts of a spectrum, it is apparent that the distinction between these two entities is no longer sufficient to identify high risk patients; rather, specific electrocardiographic changes, aspects of the clinical history, newer biochemical markers, and angiographic findings help to better distinguish higher risk individuals from a large patient population with unstable coronary syndromes and these factors usually determine therapy.

CONCLUSIONS

Based on these results, it is likely that newer therapies such as glycoprotein IIb/IIIa receptor antagonists, low molecular weight heparins, and coronary stents will be directed toward these high risk patients.

Complex stenosis morphology predicts late reocclusion during follow-up after myocardial infarction in patients with patent infarct-related coronary arteries

BACKGROUND

Whether angiographic morphology of infarct-related residual stenoses continues to affect prognosis after discharge is not known.

METHODS

We studied 175 patients after their myocardial infarction who required nonurgent coronary angioplasty for residual myocardial ischemia. The findings at diagnostic coronary angiography were compared with those before angioplasty (mean of 7 months later). Infarct-related stenoses were classified as complex or smooth. Stenosis progression was defined as >0.5 mm diameter reduction.

RESULTS

One hundred twenty-one (69%) infarct-related stenoses were complex. At restudy, total occlusion was found in 41 (35%) of the infarct-related complex stenoses compared with 7 (13%) smooth stenoses (P = .001). Reocclusion occurred in 16 (55%) of 29 complex infarct-related stenoses with thrombus, compared with 25 (28%) of 88 without thrombus (P = .01). During follow-up, 46 patients (26%) had cardiac events. Of these, 70% had complex lesions at study entry compared with 30% smooth (P < .05).

CONCLUSIONS

Residual angiographically complex stenoses after an uncomplicated myocardial infarction are associated with a greater risk of reocclusion and may predispose to coronary events at follow-up.

Histological patterns of atherosclerotic plaques in unstable angina patients vary according to clinical presentation

BACKGROUND

Unstable angina is a heterogeneous clinical syndrome. The diverse clinical presentations of unstable angina may reflect different pathogenic mechanisms within the plaque.

OBJECTIVE

To investigate the cellular constituents of culprit coronary atheromatous plaques in patients with stable angina pectoris and patients with diverse clinical presentations of unstable angina.

METHODS

48 patients who underwent coronary atherectomy for management of ischaemic heart disease: 23 had stable angina and 25 had unstable angina. Of the latter, 11 patients were classified as Braunwald's IIB and 14 as Braunwald's IIIB unstable angina. The presence of thrombus, cholesterol clefts, and smooth muscle cell proliferation was assessed in atherectomy samples using standard histological techniques. Monoclonal antibodies were used to identify smooth muscle cells and macrophages within atherosclerotic plaque fragments.

RESULTS

Fresh thrombus was more frequently found in patients with Braunwald's IIIB unstable angina (64%) than in patients with stable angina (22%) or IIB unstable angina (27%) (p < 0.0006). A pattern of smooth muscle cell proliferation ("accelerated progression pattern") was observed which was also associated with coronary thrombus. This pattern was present in 30% of patients with stable angina, 64% of patients with IIIB unstable angina, and in all patients (100%) with IIB unstable angina. Atherosclerotic plaques with thrombus, cholesterol clefts, and macrophages were more common in patients with unstable angina than in stable angina patients.

CONCLUSION

The presence of a specific smooth muscle cell proliferation (accelerated progression) pattern in patients with unstable angina, particularly in those with Braunwald's IIB unstable angina, suggests that episodic plaque disruption and subsequent healing may be an important mechanism underlying angina symptoms in these patients.

Elevated plasma lipoprotein(a) is associated with coronary artery disease in patients with chronic stable angina pectoris

OBJECTIVES

We sought to assess the relation between plasma lipoprotein(a) [Lp(a)] levels, clinical variables and angiographic coronary artery disease (CAD) in patients with chronic stable angina.

BACKGROUND

The relation between plasma Lp(a) levels and the severity and extent of angiographic CAD has not been studied in well characterized patients with stable angina pectoris.

METHODS

We investigated clinical variables, lipid variables and angiographic scores in 129 consecutive white patients (43 women) undergoing coronary angiography for chronic stable angina.

RESULTS

Plasma Lp(a) levels were significantly higher in patients with than in those without significant angiographic stenoses (> or =70%) (372 mg/liter [interquartile range 87 to 884] vs. 105 mg/liter [interquartile range 56 to 366], respectively, p=0.002). This difference remained significant when patients with mild or severe angiographic disease were compared with those with completely normal coronary arteries (312 mg/liter [interquartile range 64 to 864] vs. 116 mg/liter [interquartile range 63 to 366], respectively, p=0.02). However, subset analysis indicated that this difference achieved statistical significance only in women. Multiple logistic regression analysis indicated that Lp(a) concentration was independently predictive of significant angiographic stenoses (adjusted odds ratio [OR] 9.1, 95% confidence interval [CI] 2.0 to 42.1, p=0.006) and remained true even after exclusion of patients receiving lipid-lowering treatment (n=27) (OR 10.4, 95% CI 1.1 to 102.9, p=0.05). Lp(a) also had independent predictive value in a similar analysis using mild or severe angiographic disease as the outcome variable (OR 11.8, 95% CI 1.5 to 90.8, p=0.02).

CONCLUSIONS

Our results indicate that elevated plasma Lp(a) is an independent risk factor for angiographic CAD in chronic stable angina and may have particular significance in women.

Abnormal coronary flow in infarct arteries 1 year after myocardial infarction is predicted at 4 weeks by corrected Thrombolysis in Myocardial Infarction (TIMI) frame count and stenosis severity

Because 24% to 30% of patent infarct-related arteries occlude in the year following thrombolytic therapy for acute myocardial infarction, angiographic factors including corrected Thrombolysis in Myocardial Infarction (TIMI) frame count which may predict abnormal infarct-artery flow, require definition. We examined changes in coronary flow and infarct-artery lesion severity by computerized quantitative angiography over 1 year in 154 patients with a patent infarct-related artery 4 weeks after myocardial infarction. These patients were randomized to receive either ongoing daily therapy of 50 mg aspirin and 400 mg dipyridamole, or placebo. All angiograms were interpreted blind in our core angiographic laboratory. Infarct-artery flow, assessed by corrected TIMI frame counts, was normal (< or = 27) in 46% and 45% of patients at 4 weeks and 1 year, respectively. At 4 weeks, patients with corrected TIMI frame counts < or = 27 had higher ejection fractions (60+/-11% vs 56+/-12%; p = 0.04) than those with corrected TIMI frame counts >27. On multivariate analysis, corrected TIMI frame count and stenosis severity were predictive of late abnormal infarct-artery flow (TIMI 0 to 2 flow, both p <0.01). Only stenosis severity at 4 weeks predicted reocclusion at 1 year (p <0.0001). Aspirin and dipyridamole had no effect on flow or reocclusion. Thus, corrected TIMI frame count and stenosis severity at 4 weeks was highly correlated with infarct-artery flow at 1 year.

Angioscopic evaluation of angiographically complex coronary lesions

Coronary angioscopy (CA) provides direct visualization of the endoluminal surface of coronary vessels. The usefulness of CA during coronary angioplasty of angiographically complex lesions remains to be established. This study was designed to determine the value of CA to elucidate the underlying substrate of angiographically complex lesions. Forty-seven consecutive patients with angiographically complex lesions were studied with CA before coronary intervention. Mean age of the group was 59 +/- 9 years; six patients were women. Forty (85%) patients had unstable angina. Complex angiographic lesions included coronary occlusions (n = 23) (14 with Thrombolysis in Myocardial Infarction coronary flow grade 0 and nine with flow grade 1), lesions with intraluminal filling defects suggestive of thrombus or ulceration (n = 8), and lesions that were highly eccentric (n = 16). Items analyzed with CA included red thrombus (lining or protruding) and plaque color (yellow, white, or mixed). In all patients, CA visualized the protruding material causing the angiographic appearance. At this site CA detected red thrombus in 34 (72%) patients (14 protruding, 20 lining) and atherosclerotic plaque in 45 (96%) patients. At the site of the angiographically complex lesion, plaque was classified as predominantly yellow in 24 patients, mixed in 12, and white in nine. The incidence of thrombus on CA was higher for occluded vessels (91%) or lesions with intraluminal filling defects or ulceration (87%) than in eccentric lesions (37%) (p < 0.05). However, plaque coloration was not significantly different among these three angiographic subgroups. Initial procedural success (without stent requirement) was lower in lesions showing protruding thrombus on CA (64% vs 91 %, p < 0.05). Thus most angiographically complex lesions contain thrombus. On CA red thrombus was more frequently identified on occluded vessels and lesions with filling defects or ulceration than in eccentric lesions. Yellow or mixed plaques are common in these patients, suggesting lipid-laden plaques as the underlying pathologic substrate of angiographically complex lesions.

Revascularization of patients with unstable coronary artery disease: the case for early intervention

In unstable angina, there are data to suggest a substantial risk of recurrent ischemia, infarction, and death when early angiography and/or revascularization have been deferred. Conversely, it has been suggested that early angiography and revascularization are more dangerous than deferred procedures. Critical review of the literature, however, suggests that there is no specific risk inherent in early intervention, but rather that patients who cannot wait are at higher risk anyway. The most valuable data on the comparison of an "early invasive" and a "conservative" strategy in unstable angina come from the Thrombolysis in Myocardial Ischemia (TIMI) IIIB study. The results show no major difference in outcome between groups (despite a high intervention rate in the conservative group), but a shorter hospital stay, lower drug use, and fewer rehospitalizations in the group treated according to the early invasive strategy. These results have been interpreted as favoring early intervention, due to the potential for a shorter hospital stay (a major determinant of cost in many countries) because of the possibility of achieving complete diagnosis and treatment within several days of admission, with good results. In addition, since the inception of the TIMI IIIB study, there have been major improvements in the field of angioplasty, such as the increased use of stents and the availability of safe and effective glycoprotein (GP) IIb-IIIa inhibitors. Thus, the pathophysiology, the excellent results of early intervention, and the recent improvements in angioplasty and its medical and pharmacologic environment, provide a strong rationale for early intervention.

Progression of the culprit lesion in unstable coronary artery disease with warfarin and aspirin versus aspirin alone: preliminary study

OBJECTIVES

This study assessed whether combination therapy with aspirin and warfarin for 10 weeks reduces the risk of progression or reocclusion of the unstable coronary artery lesion.

BACKGROUND

Reocclusion of the culprit coronary artery occurs in up to one third of patients during the 3 months after myocardial infarction (MI) or unstable angina and is associated with increased morbidity and mortality.

METHODS

Fifty-seven patients presenting with unstable angina or MI who had an identifiable culprit lesion at coronary angiography were randomized in double-blind manner to receive warfarin (target international normalized ratio [INR] 2.0 to 2.5) or placebo in addition to aspirin (150 mg daily). Changes in the culprit lesion were assessed by quantitative angiography in 50 patients after 10 weeks of therapy or after a clinical event. Progression of the culprit lesion was defined as a decrease in minimal lumen diameter > 0.4 mm or a new total occlusion. Regression was defined as an increase in minimal lumen diameter > 0.4 mm.

RESULTS

In subjects randomized to receive warfarin, the culprit lesion was less likely to progress (1 [4%] vs. 8 [33%]) and more likely to regress (5[19%] vs. 2[9%]) than in subjects receiving placebo (p = 0.02). Recurrent MI or a new occlusion at angiography occurred in 2 (7%) of 29 patients receiving warfarin versus 11 (39%) of 28 patients receiving placebo (p = 0.005).

CONCLUSIONS

In patients with an acute coronary syndrome, combined therapy with aspirin and warfarin with a target INR of 2.0 to 2.5 for 10 weeks reduces the risk of progression or reocclusion of the culprit coronary lesion.

Angiographic features of vein grafts versus ungrafted coronary arteries in patients with unstable angina and previous bypass surgery

OBJECTIVES

The aim of the study was to compare the angiographic features of culprit coronary lesions located in grafts with those in native coronary arteries in patients with unstable angina and previous coronary artery bypass graft surgery (CABG).

BACKGROUND

Deterioration of angina in patients with previous CABG is usually due to progression of atherosclerosis in coronary arteries or in vein grafts, but the relative importance of graft versus native coronary artery disease as well as the morphologic features of the culprit lesions in unstable angina have not been systematically assessed.

METHODS

Disease progression and angiographic features of vein grafts and ungrafted and grafted coronary arteries were assessed in 95 consecutive patients admitted with unstable angina or non-Q wave myocardial infarction with CABG > 6 months previously. All patients were receiving aspirin and heparin, and 46 had received streptokinase during the acute phase in a doubleblind, placebo-controlled study. Coronary and vein angiography was performed within 8 days after admission (mean [+/- SD] 5 +/- 2 days). The most recent angiogram served to assess disease progression by quantitative angiography.

RESULTS

The culprit lesion was located in a vein graft in 51 patients, an ungrafted coronary artery in 17 and a grafted artery (proximal and distal to the site of graft insertion) in 9 and was of undetermined site in the remaining 18. The proportion of grafts accounting for acute disease increased to 85% with CABG > or = 5 years. Total occlusion occurred in 25 vein grafts and 4 ungrafted coronary arteries (49% vs. 24%, p = 0.02). Intravessel thrombus was found in 18 culprit vein grafts but in only 2 ungrafted coronary arteries (37% vs. 12%, p = 0.04). Both intravessel thrombus and total occlusion were demonstrated in six culprit vein grafts but in none of the ungrafted coronary arteries (12% vs. 0%, p = NS). The prevalence of total occlusion and thrombus was not influenced by trial medication, streptokinase or placebo.

CONCLUSIONS

Unstable angina in patients with previous CABG is most often due to graft disease and is associated with more frequent thrombi that are more refractory to medical therapy.

The natural history of unheralded complex coronary plaques

OBJECTIVES

This study sought to assess the behavior of unheralded complex lesions in patients with no previous history of acute coronary ischemia.

BACKGROUND

Angiographically complex coronary stenoses appear to originate from plaque disruption and are associated with rapid progression early and late after acute coronary events. Complex lesions may occur without symptoms, but neither the incidence nor the behavior of these unheralded complex lesions is known.

METHODS

We studied 222 patients with chronic stable angina who were on a waiting list for single-vessel percutaneous transluminal coronary angioplasty of an unoccluded lesion and underwent repeat angiography immediately before the procedure as part of routine practice or shortly after a coronary event. Patients with a previous episode of myocardial infarction or unstable angina were not included. Angiograms were analyzed quantitatively and qualitatively using established methods. A change of +/- 15% stenosis severity or total coronary occlusion defined categoric change.

RESULTS

At first angiography, there were 52 unheralded complex target lesions (23%) and 170 smooth target stenoses (77%). Stenosis severity did not differ between complex and smooth target lesions at first and second angiography at a mean (+/- SD) interval of 7 +/- 4 months. At follow-up, seven complex lesions had progressed (14%) compared with six smooth lesions (4%, p < 0.02). Total occlusion developed in four complex lesions and one smooth lesion. Overall, complex stenoses progressed by 3 +/- 13% compared with 0.5 +/- 7% in the smooth stenoses (p = 0.15). Complex stenoses were 4.2 times more likely to progress than smooth stenoses (95% confidence interval 1.2 to 15.2 [Cornfields method]). Clinical events developed in seven patients. One complex lesion regressed and became smooth, and three smooth stenoses became complex at follow-up.

CONCLUSIONS

Morphologically complex stenosis can develop without an episode of acute coronary ischemia and are relatively common in patients awaiting single-vessel angioplasty. Our study demonstrates that like their clinically heralded counterparts, these unheralded complex stenoses are at higher risk of progression than smooth stenoses.

Plasma immunoreactive endothelin concentration correlates with severity of coronary artery disease in patients with stable angina pectoris and normal ventricular function

OBJECTIVES

The present study tested the hypothesis that plasma immunoreactive endothelin concentration correlates with the severity and extent of coronary atherosclerosis.

BACKGROUND

Plasma endothelin-1 concentration is increased in patients with unstable coronary syndromes and advanced atherosclerosis. This finding, together with other clinicopathologic observations, suggests that endothelins may participate in the atherogenic process. However, the relation between plasma immunoreactive endothelin and coronary artery disease in patients with stable angina pectoris remains controversial.

METHODS

Ninety consecutive patients undergoing coronary angiography for the investigation of exertional chest pain and 49 normal control subjects were prospectively studied. Eleven patients had normal coronary angiographic findings (group I), 65 had coronary artery stenoses (group II), and 14 had coronary artery disease plus symptoms indicating atheroma in other vascular territories (group III). Computerized angiography was used to determine the extent, severity and morphology of coronary stenoses. Plasma immunoreactive endothelin was measured by radioimmunoassay.

RESULTS

Mean (+/- SD) plasma endothelin concentration (pg/ml) was significantly higher in patients than in control subjects (7.29 +/- 4.07 vs. 3.48 +/- 1.29, p < 0.0001). Endothelin levels were higher in patients of group III than in those of groups II and I (9.43 +/- 5.48, 7.20 +/- 3.72 and 4.94 +/- 2.89, respectively, p = 0.02). In patients of group II, plasma endothelin correlated with the maximal degree of stenosis in each patient (r = 0.25, p = 0.04) and with the number of stenoses with > or = 70% diameter narrowing (r = 0.36, p = 0.002). The highest plasma endothelin levels were found in patients with total occlusions (8.65 +/- 3.78 vs. 6.46 +/- 3.51 p = 0.02).

CONCLUSIONS

Plasma immunoreactive endothelin concentration is increased in patients with chronic stable angina. The higher levels occur in patients with severe stenoses and total coronary occlusion.

Pathophysiology and inflammatory aspects of plaque rupture

Atherosclerotic plaque disruption with superimposed thrombosis is the main cause of acute coronary events. At present it is not known specifically how various risk factors influence the development and configuration of coronary plaques. The risk of plaque disruption depends more on plaque composition and vulnerability (plaque type) than on the degree of stenosis (plaque size). Lipid accumulation and chronic inflammation, particularly macrophage activities, seem to influence the development and the stability of a plaque and thus its propensity to rupture. Macrophages have the ability to secrete proteolytic enzymes and often infiltrate the region of imminent plaque rupture, and disruption may be associated with a generalized inflammatory reaction. Further, plaque disruption tends to occur at points where the plaque surface is weakest, corresponding to locations where mechanical and hemodynamic forces have their highest impact. The risk of plaque disruption is a function of both plaque vulnerability (intrinsic disease) and rupture triggers (extrinsic forces). The former predisposes the plaque to rupture; the latter may precipitate rupture. The danger of vulnerable plaques, however, is not related to disruption as such but to the resulting thrombosis. The magnitude of this thrombotic response and the ensuing flow obstruction depends on the contents and quantity of exposed thrombogenic plaque material, the degree of pre-existing stenosis, and the systemic thrombotic tendency. The thrombotic response is a dynamic process that is decisive for the clinical presentation and the outcome.

Role of plaque size and degree of stenosis in acute myocardial infarction

Angiographically apparent coronary artery stenoses limit coronary flow, produce symptomatic ischemia, and can be targeted for revascularization. Severe stenoses are more likely to occlude than segments without significant stenoses. Coronary angiography underestimates the extent of coronary atherosclerosis. Arterial segments without severe stenoses are much more common, and their risk of occlusion is not zero. Thus, the majority of myocardial infarctions are due to occlusion of arteries that do not contain obstructive coronary stenoses. Consequently, coronary angiography is not able to accurately predict the site of a coronary artery occlusion that subsequently will produce myocardial infarction.