Unstable angina. A comparison of angioscopic findings between diabetic and nondiabetic patients

Role of diabetes in atherosclerotic pathogenesis. What have we learned from animal models?

Diabetes mellitus is associated with a greater risk of developing atherosclerosis and its complications: stroke, myocardial infarction, and peripheral vascular disease. In patients with diabetes, atherosclerosis represents a complex multifactorial disease with increased lesion progression and severity compared to the nondiabetic population. Several risk factors have been proposed to explain the increased risk of cardiovascular disease with diabetes. They include: hyperglycaemia, dyslipidemia, accelerated formation of advanced glycation end-products (AGEs), increased oxidative stress, and genetic factors. It is difficult to precisely establish the elements leading to diabetes-accelerated atherosclerosis by means of epidemiological studies because all these factors coexist in diabetic patients. Thus, diabetic animal models that reproduce exacerbation of atherosclerosis would be helpful to understand why atherosclerosis is accelerated by diabetes, and to design appropriate treatments to limit its progression. This review analyzes most of the animal models developed to reproduce diabetes-accelerated atherosclerosis, and summarizes the effects of hyperglycaemia and lipid abnormalities on atherogenesis.

Insulin resistance and atherosclerosis

The epidemic of obesity in the developed world over the last two decades is driving a large increase in type 2 diabetes and consequentially setting the scene for an impending wave of cardiovascular morbidity and mortality. It is only now being recognized that the major antecedent of type 2 diabetes, insulin resistance with its attendant syndrome, is the major underlying cause of the susceptibility to type 2 diabetes and cardiovascular disease. In metabolic tissues, insulin signaling via the phosphatidylinositol-3-kinase pathway leads to glucose uptake so that in insulin resistance a state of hyperglycemia occurs; other factors such as dyslipidemia and hypertension also arise. In cardiovascular tissues there are two pathways of insulin receptor signaling, one that is predominant in metabolic tissues (mediated by phosphatidylinositol-3-kinase) and another being a growth factor-like pathway (mediated by MAPK); the down-regulation of the former and continued activity of the latter pathway leads to atherosclerosis. This review addresses the metabolic consequences of the insulin resistance syndrome, its relationship with atherosclerosis, and the impact of insulin resistance on processes of atherosclerosis including insulin signaling in cells of the vasculature.

Cardiovascular effects of the thiazolidinediones

Thiazolidinediones, used for the treatment of diabetes mellitus type 2, modulate gene expression by binding to nuclear transcription factor, peroxisome proliferator-activated receptor-gamma. Peroxisome proliferator-activated receptor-gamma is expressed in several tissues, therefore, thiazolidinediones have biological effects on multiple organ systems. Here, we describe evidence that thiazolidinediones have beneficial effects on the cardiovascular system independent of their antidiabetic effect. Studies in animals have clearly shown that thiazolidinediones decrease blood pressure, left ventricular hypertrophy, development of atherosclerotic lesions, and protect myocardium from ischemia/reperfusion injury. Although relatively few studies in humans have been reported, the preponderance of available evidence suggests a beneficial effect of thiazolidinediones. Thus, by modulating gene expression, thiazolidinediones may provide a novel method for the prevention and treatment of cardiovascular diseases.

Coronary heart disease in women: why the disproportionate risk?

Women with diabetes experience much greater relative risks of coronary heart disease (CHD) compared with the nondiabetic population than do men with diabetes. In type 2 diabetes, much of the greater elevation in risk in women is explained by a more adverse pattern of known CHD risk factors. In type 1 diabetes the picture is less clear, but current evidence suggests that a cardioprotective lipid profile is found in type 1 diabetic men, thus reducing the effect of diabetes on CHD, but that in women this is not the case. Also, in type 1 diabetic women there is some evidence of altered body fat distribution and a greater elevation in blood pressure. Whether these reflect a greater degree of insulin resistance in type 1 women, and what the origin of this might be, remains controversial. The practical consequence is that clinicians need to be aware that the usual cardioprotective effect of sex does not apply in diabetic women and that risk factor intervention is needed at an early age.

Drug-Eluting Coronary Stents

The introduction and widespread use of coronary stents have been the most important advancement in the percutaneous treatment of coronary artery disease since the introduction of balloon angioplasty. Coronary artery stents reduce the rate of angiographic and clinical restenosis compared to balloon angioplasty. This angiographic restenosis was further reduced with the introduction of drug-eluting stents and hence further reduction in the frequency of major adverse cardiac events. Herein we present a comprehensive and up-to-date review about the use of drug-eluting stents in the treatment of coronary artery disease.

Nature of coronary disease in patients with insulin resistance and its impact on revascularization strategies

Data on the nature of coronary artery disease in patients with insulin resistance and its treatment have been obtained mostly in the diabetic population. The 'quantitative' and 'qualitative' changes in the course of coronary artery disease and the relationship with the increased rate of cardiac events in this population will be discussed. The effects of various methods of revascularization (bypass surgery vs. percutaneous revascularization) and the potential benefit of recent adjuncts to percutaneous revascularization (stents, drug-eluting stents, antiplatelet agents) will be discussed.

Integrated Management of Patients with Diabetes Mellitus and Ischemic Heart Disease: PCI, CABG, and Medical Therapy

Modern coronary revascularization strategies are based on studies performed in the 1970s and 1980s that compared coronary artery bypass surgery with standard medical therapy available at the time. Studies comparing surgical and percutaneous revascularization followed, demonstrating similar long-term outcome among thousands of randomized patients. The largest of these trials, the Bypass Angioplasty Revascularization Investigation (BARI), cast doubt on the generalizability of these findings to all subgroups, finding that patients with diabetes mellitus and multivessel disease had worse long-term outcome with an initial strategy of percutaneous transluminal coronary angioplasty (PTCA). Indeed, patients with diabetes mellitus are at increased risk for cardiovascular morbidity and mortality, while the benefit of standard therapies in these patients is attenuated by the underlying metabolic abnormalities and significant comorbidities associated with the diabetic state. However, surgical and percutaneous revascularization techniques continue to evolve. Similarly, modern medical therapy is markedly superior to that available during these early studies, with demonstrable benefit in primary and secondary prevention of vascular events in both diabetic and nondiabetic patients. Ongoing trials will define the impact of current treatment modalities in this important and growing population.

Serum hepatocyte growth factor levels predict long-term clinical outcome after percutaneous coronary revascularization

AIMS

To evaluate, in patients referred for elective percutaneous coronary revascularization (PCR) without heparin pre-treatment, the relationship between baseline serum levels of the angiogenic growth factors, vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF), and clinical outcome.

METHODS AND RESULTS

In 488 consecutive patients undergoing elective coronary angioplasty, hsC-reactive protein, HGF, and VEGF levels were measured before heparin administration. The primary endpoint, a composite of death and myocardial infarction, occurred in 44 patients at a median follow-up of 14.9 months. At baseline, VEGF levels were related to C-reactive protein levels and inversely related to age; HGF levels were related to C-reactive protein levels, diabetes, and recent clinical instability. In the univariate analysis, HGF had a significant positive relationship (P=0.003) with the primary endpoint. A similar trend was observed for VEGF (P=0.11). The only three variables significantly associated with the primary endpoint in the multivariable Cox model were HGF (P=0.004), C-reactive protein (P=0.007), and diabetes (P=0.04).

CONCLUSION

Our results demonstrate that in patients, without heparin pre-treatment, referred for PCR, a high serum level of HGF is an independent predictor of clinical events during follow-up and is correlated with other surrogate measures of the activity of atherosclerosis.

Increased heat generation from atherosclerotic plaques in patients with type 2 diabetes: an increased local inflammatory activation

OBJECTIVE

Patients with coronary artery disease (CAD) and diabetes show increased inflammatory activation. Thermography detects local inflammatory involvement as heat generation. The aim of this study was to investigate whether patients with CAD and diabetes have increased local heat generation compared with nondiabetic patients.

RESEARCH DESIGN AND METHODS

We enrolled patients undergoing percutaneous coronary interventions: 45 diabetic patients and 63 nondiabetic patients, serving as the control group, matched for age, type of clinical syndrome, statin and aspirin intake, and angiographic stenosis (%). Coronary thermography was performed, and temperature difference (DeltaT) between the atherosclerotic plaque and the proximal vessel wall was measured.

RESULTS

Patients with diabetes had increased temperature difference compared with nondiabetic patients (DeltaT: 0.17 +/- 0.18 degrees C vs. 0.09 +/- 0.02 degrees C, P = 0.01). Twenty-one diabetic and 22 nondiabetic patients suffered from acute coronary syndromes (ACSs) (P = 0.22). Patients with diabetes and ACSs had increased temperature difference compared with nondiabetic patients with ACSs (DeltaT: 0.29 +/- 0.31 degrees C vs. 0.15 +/- 0.21 degrees C, P = 0.02), which is the same as patients with diabetes and chronic stable angina (DeltaT: 0.09 +/- 0.08 degrees C vs. 0.05 +/- 0.04 degrees C, P = 0.006). Twenty-three diabetic and 30 nondiabetic patients were under therapy with statins (P = 0.72). Patients with diabetes under statins had lower temperature difference compared with untreated patients (DeltaT: 0.11 +/- 0.12 degrees C vs. 0.22 +/- 0.21 degrees C, P = 0.02), which is the same as nondiabetic patients under statins (DeltaT: 0.05 +/- 0.04 degrees C vs. 0.13 +/- 0.18 degrees C, P = 0.01).

CONCLUSIONS

Patients with diabetes have increased temperature difference compared with nondiabetic patients. Patients with diabetes under statins showed decreased temperature difference compared with untreated patients, suggesting that statins have a favorable effect in patients with diabetes and CAD.

Diabetic patients with acute coronary syndromes in the UK: high risk and under treated. Results from the prospective registry of acute ischaemic syndromes in the UK (PRAIS-UK)

OBJECTIVES

Short-term randomised trials suggest that patients with diabetes mellitus (DM), admitted with acute coronary syndromes (ACS) are at increased risk of subsequent adverse events. We tested whether this hypothesis was true for an unselected population of ACS patients with and without DM admitted with non-ST elevation MI or unstable angina, in a non-trial setting over a longer term of follow-up.

METHODS

Prospective, centrally, coordinated multicenter registry involving 56 centers throughout the UK (half having angiographic facilities). Consecutive patients admitted with ACS without ST elevation on the presenting ECG were followed up to 6 months. A sub-group of patients were flagged with the UK Office for National Statistics and followed-up for death over 4 years.

RESULTS

Data were collected on 1046 ACS patients of whom 170 (16%) had a prior diagnosis of DM. DM patients had higher baseline co-morbidities and unadjusted mortality rates at 6 months (11.8% vs. 6.4%, p=0.01). After correcting for clinical variables such as age, gender, smoking status and chest pain/ischaemic ECG changes on admission, prior history of any of myocardial infarction, heart failure, hypertension, hypercholesterolemia (on treatment), stroke or coronary revascularisation (PTCA or CABG), mortality rates for DM patients were no longer significantly raised (hazard ratio 1.35, 95% CI: 0.79-2.30; p=0.27 at 6 months and 1.15, 95% CI 0.72-1.83 at 4 years). 30% of diabetics were dead after 4 years of follow-up. Patients with DM were more likely to have been revascularised at 6 months and were more likely to receive ACE inhibitors. Based on the rate of recruitment and the population covered in the study, about 21,000 patients with DM will be admitted with non-ST elevation ACS each year in the UK.

CONCLUSIONS

DM is common amongst patients admitted with ACS without ST elevation and is associated with significant morbidity and mortality: approximately 1 in 8 will not survive up to 6 months and 1 in 3 to 4 years. DM patients should be managed aggressively to reduce their risk of future complications.

Pathobiology and cell interactions of platelets in diabetes

Diabetes is a well-recognised risk factor for atherosclerotic cardiovascular disease and in fact most diabetic patients die from vascular complications. The Diabetes Control and Complications Trial (DCCT) and the U.K. Prospective Diabetes Study (UKPDS) indicate a consistent relationship between hyperglycaemia and the incidence of chronic vascular complications in patients with diabetes. Platelets are essential for haemostasis, and abnormalities of platelet function may cause vascular disease in diabetes. Diabetic patients have hyperreactive platelets with exaggerated adhesion, aggregation and thrombin generation. In summary, the entire coagulation cascade is dysfunctional in diabetes. This review provides a comprehensive overview of the physiological role of platelets in maintaining haemostasis and of the pathophysiological processes that contribute to platelet dysfunction in diabetes and associated cardiovascular diseases, with special emphasis on proteomic approaches and leukocyte-platelet cross-talk.

Determination of vessel size: a putative framework to assess clinical outcome

BACKGROUND

Unknown is the predictive value of the coronary artery diameter without the administration of vasomotor stimuli. A small reference diameter of the target vessel has been demonstrated to be an adverse prognostic factor in patients undergoing revascularisation. The present study investigated the prognostic value of the proximal non-stenotic left anterior descending coronary artery (LAD) diameter in patients referred for a first diagnostic angiogram without a previous revascularisation.

METHODS

A total of 277 patients (mean age 57 year, 61% male) were eligible for analysis. The proximal non-stenotic diameter of the LAD was measured by quantitative coronary angiography without prior nitrate infusion. We defined a small LAD as a diameter < or =2.5 mm. Cardiovascular events were defined as cardiac death, myocardial infarction, and hospitalizations for unstable angina.

RESULTS

During a median follow-up of 47 months, 24 major cardiac events occurred. The cumulative survival for patients with a small LAD was significantly lower, than for patients with a large LAD (hazard ratio 2.51; 95% confidence interval 1.11-5.66, p=0.03). In the multivariate analysis, a LAD diameter < or =2.5 mm remained a significant predictor of cardiovascular events after adjustment for age, gender, and the presence of significant coronary artery disease (hazard ratio 2.32; 95% confidence interval 1.01-5.34, p=0.048).

CONCLUSION

In patients referred for a first diagnostic angiogram without a previous revascularisation, the diameter of the proximal non-stenotic LAD is an independent predictor of cardiovascular events.

Coronary atherosclerosis in diabetic subjects: clinical significance, anatomic characteristics, and identification with in vivo imaging

Diabetes mellitus is an endocrine disorder that promotes the development and progression of atherosclerotic coronary disease. As a consequence, cardiovascular disease is the most important cause of morbidity and mortality in diabetics. Early identification and treatment of asymptomatic stages provides the opportunity to prevent cardiovascular end organ complications. Modem clinical imaging modalities allow the assessment of early atherosclerotic changes in coronary arteries; however, prospective evidence that atherosclerosis imaging impacts on clinical outcome is not yet available and future studies are necessary.

Impact of age and hyperglycemia on the mechanical behavior of intact human coronary arteries: an ex vivo intravascular ultrasound study

Despite their advantages, percutaneous coronary interventional procedures are less effective in diabetic patients. Changes in the mechanical properties of vascular walls secondary to long-term hyperglycemia as well as other factors such as age may influence coronary distensibility. This investigation is aimed at deciphering the extent of these effects on distensibility of postmortem human coronary arteries in a controlled manner. Excised human left anterior descending (LAD) coronary arteries were obtained within 24 h postmortem. With the use of intravascular ultrasound, vascular deformation was analyzed at midregions of 51 moderate lesions. Intraluminal pressure was systematically altered using a computerized pressure pump system and monitored by a pressure-sensing guidewire. Distensibility, a normalized compliance term, was defined as the change in lumen area normalized by the initial reference area over a given pressure interval. With the use of multivariate analysis and repeated-measures ANOVA, coronary distensibility was independently influenced by hyperglycemia and age (P < 0.05) through the entire pressure range. Within physiological pressure range, distensibility was significantly reduced with age in nonhyperglycemic coronary specimens (10.55 +/- 4.41 vs. 6.99 +/- 2.45, x10(3) kPa(-1), P = 0.01), whereas the hyperglycemic vessels were stiff even in the younger group (7.90 +/- 5.82 vs. 7.20 +/- 3.36, x10(3) kPa(-1), P = 0.79). Similar results were observed with stiffness index and elastic modulus of the arteries. Hyperglycemia and age independently influenced the distensibility of moderately atherosclerotic LAD coronary arteries. The stiffening with age was overshadowed in the hyperglycemic group by as-yet-undetermined factors.

Metabolic syndrome: an appraisal of the pro-inflammatory and procoagulant status

Inflammation and hypercoagulability predispose to atherothrombosis and seem to be important features of the metabolic syndrome. The most convincing evidence is the association with increased levels of C-reactive protein. The hemostatic abnormality that has been most consistently associated with insulin resistance is an elevated plasminogen activator inhibitor-1 level. In contrast, markers of hypercoagulability have been associated inconsistently with hyperinsulinemia and glucose intolerance. Fibrinogen clusters with inflammatory factors, which suggests involvement of adipose tissue-generated inflammatory cytokines. Elevated von Willebrand's factor and factor VIII levels aggregate with indicators of endothelial injury,whereas vitamin K-dependent coagulation proteins correlate with triglyceride levels.

Management of the patient with diabetes mellitus and myocardial infarction: clinical trials update

The increasing prevalence of diabetes mellitus and its association with cardiovascular disease have become serious public health issues. Although diabetes and coronary artery disease (CAD) may have different clinical manifestations, their atherosclerotic burden and prognosis are quite similar. However, patients with diabetes who have underlying CAD have a different, more complex pathophysiology and a worse prognosis. Optimal management of these patients requires a comprehensive multifactorial approach to prevent microvascular and macrovascular events. In the setting of an acute myocardial infarction (MI), immediate management should focus on limiting infarct size. This can be achieved by using fibrinolytic agents, primary percutaneous intervention (in ST-segment elevation MI), or glycoprotein IIb/IIIa inhibitors followed by coronary angiography within 24 to 48 hours and, when appropriate, by coronary intervention (in non-ST-segment elevation MI). Drug-eluting stents may have an important role in patients with diabetes, who have a higher rate of postintervention coronary restenosis than do nondiabetic individuals. In addition, all patients with an acute MI (ST- and non-ST-segment elevation) should be given aspirin, nitrates, beta-blockers, and angiotensin-converting enzyme (ACE) inhibitors. The long-term pharmacologic management after MI is similar in all patients, regardless of the initial presentation. Antiplatelet agents (aspirin and/or clopidogrel), ACE inhibitors, beta-blockers, lipid-lowering agents, and glycemic control have all been shown to be effective in decreasing long-term mortality. Despite advances in the management of MI, the mortality rates of patients with diabetes remain 1.5- to 2-fold greater than those of persons without diabetes. Maximizing the use of lifesaving therapies proved effective in large randomized clinical trials and tight metabolic control can further decrease mortality rates. However, many of these lifesaving therapies are underused in patients with diabetes because of the misconception that potential adverse effects may outweigh their benefits. New programs aimed at improving postinfarction quality of care in patients with diabetes, based on guidelines and expert recommendations, have shown promise. However, more effort must be devoted to the improvement of outcomes related to these public health problems.

A comparative study of rotational atherectomy in acute and stable coronary syndromes in the modern era

Percutaneous rotational coronary atherectomy (PRCA) is commonly used in the percutaneous treatment of diffuse, calcified coronary lesions in stable coronary syndromes (SCSs) and facilitates successful delivery and deployment of balloons and stents. Early experience with PRCA cautioned its use in acute coronary syndromes (ACSs). However, the evolution of the PRCA technique and improved antiplatelet pharmacotherapy has broadened its use in ACSs also. A total of 1,112 consecutive patients with an ACS (n=269) or SCS (n=843) who underwent PRCA of 1,483 lesions were examined retrospectively to evaluate the angiographic and short-term clinical outcomes. Troponin-I was elevated in 33.3% of the ACS group and in 0.6% of the SCS group at baseline (p<0.001). Angiographic complications occurred more frequently in the ACS group (18.6% vs 13.1%, p=0.02). There was no difference in major complications between the groups (ACS 1.1% vs SCS 0.8%; p=0.44). The incidence of any periprocedural creatinine kinase-MB elevation was 17.1% versus 18.9% (p=NS) and 30-day major adverse cardiac events (death, disabling stroke, creatine kinase-MB >3 times the upper limit of normal, urgent revascularization) was 5.9% versus 4.6% (p=NS) when comparing the ACS and SCS groups, respectively. With current techniques and antiplatelet therapy, PRCA can be safely performed in ACSs when lesion morphology dictates, with outcomes comparable to that achieved in SCSs. Although angiographic complications occurred more frequently in the ACS group, this did not result in a significantly higher incidence of postprocedural myonecrosis or 30-day major adverse cardiac events.

Long-term clinical benefits of a platelet glycoprotein IIb/IIIa receptor blocker, abciximab (ReoPro), in high-risk diabetic patients undergoing percutaneous coronary intervention

BACKGROUND

High-risk percutaneous coronary interventions (PCIs) are associated with a high complication rate, a low procedural success rate and a high restenosis rate, especially in diabetics. We sought to determine whether abciximab (ReoPro) therapy affects long-term clinical outcomes of Korean patients with diabetes undergoing high-risk PCI.

METHODS

One hundred and nineteen patients with 152 lesion sites were administered ReoPro among 2,231 patients who underwent PCI at Chonnam National University Hospital from March 1999 to Feb 2001. These 119 patients were divided into two groups, 30 were allocated to a diabetic group (Group 1, 57.7 +/- 8.2 years, 22 male), and 89 to a non-diabetic group (Group II, 59.6 +/- 10.8 years, 68 male). Early and long-term clinical outcomes after PCI were analyzed.

RESULTS

In terms of clinical diagnosis, the number of acute myocardial infarctions in Group I was 25 (83.3%) and 76 in Group II (85.4%). As for risk factors, target artery lesions, and ACC/AHA types, no differences were found between the two groups. The number of patients with total occlusion was 21 (55.3%) and 62 (53.9%), and the number with a thrombus-containing lesion was 28 (93.3%) and 88 (98.9%) in Groups I and II, respectively. The procedure was successful in 27 (90.0%) in Group I, and in 80 (89.9%) in Group II, and no differences were evident between the two groups in terms of bleeding complications. No major adverse cardiac events (MACE), including myocardial infarction, repeat revascularization or cardiac death, were observed in Group I, but 8 cases of MACE occurred in Group II during hospitalization. Clinical follow-up was performed in 116 patients (97.5%) over 18.5 +/- 6.7 (5-28) months. The number of overall MACEs was 10 (3.3%) in Group I and 14 (15.7%) in Group II (p = 0.038).

CONCLUSION

ReoPro used in high-risk PCI in diabetics was effective in terms of early clinical outcomes, but its long-term clinical benefits were not proven.

Sex-based differences in serum cardiac troponin I, a specific marker for myocardial injury, after cardiac surgery

BACKGROUND

Prevalence and causes of sex-based differences in morbidity and mortality secondary to cardiovascular disease remain controversial. Cardiac troponin I (cTnI) is a sensitive and specific marker for myocardial injury. Serial cTnI measurements have been used to identify perioperative myocardial cell injury.

OBJECTIVE

To determine whether sex influences the extent of myocardial injury during cardiac surgery, we measured perioperative cTnI in male and female patients.

DESIGN

A total of 17 male and 17 female patients were prospectively studied in an age- and case-matched manner. Arterial cTnI were obtained preinduction, 30 mins after the application of the aortic cross-clamp, at arrival to the intensive care unit, and on postoperative day 1.

SETTING

Tertiary cardiac surgery center at a major teaching hospital.

RESULTS

There was no difference between men and women in body mass index (kg/m2), duration of cardiopulmonary bypass, and aortic cross-clamp times. Preoperative cTnI measurements were similar in men (0.24 +/- 0.15 ng/mL) and women (0.25 +/- 0.13 ng/mL, mean +/- sem). The maximum serum cTnI occurred on postoperative day 1 in all patients, and it was 3-fold higher in men (18.5 +/- 5.7 ng/mL) compared with women (6.4 +/- 1.0 ng/mL).

CONCLUSIONS

Men had markedly higher serum cTnI compared with women, although they were case matched with respect to age and cardiac risk factors. Our results may suggest there may be sex-related differences in the myocardial response to ischemia and reperfusion injury or intrinsic differences between the male and female myocardium.

Effects of statins on the vasculature: Implications for aggressive lipid management in the cardiovascular metabolic syndrome

The cardiovascular metabolic syndrome is a family of risk factors that predispose patients to develop diabetes and cardiovascular disease. Indeed, macrovascular, not microvascular, disease is the leading cause of death in these patients. The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) exert both direct and indirect (cholesterol-lowering) effects on the vasculature. Clinical trials have shown that these agents reduce cardiovascular disease and cerebrovascular disease in persons with diabetes. However, their beneficial effects on diabetic dyslipidemia do not account for all of the observed risk reduction. Positive effects on nitric oxide metabolism, inflammation, coagulability, and adhesion of cells to the vascular endothelium likely contribute to the mechanism of action of these agents. These pleiotropic effects of statins on the vasculature will be discussed in this review.

[Prognostic value of troponin T in hospitalized patients with angina or non-ST-segment elevation myocardial infarction]

INTRODUCTION AND OBJECTIVES

Cardiac troponins are highly specific and sensitive for detecting minimal myocardial damage. The aim of our study was to determine the prognostic value of troponin T levels in patients hospitalized for suspected angina or myocardial infarction without ST-segment elevation.

PATIENTS AND METHOD

We recorded the frequency of death, acute myocardial infarction, heart failure, or need for coronary revascularization in the three months after the onset of symptoms in 346 consecutive patients admitted for suspected acute coronary syndrome, excluding those who developed myocardial infarction with persistent ST-segment elevation.

RESULT

. Serum troponin T levels were > or = 0.1 ng/ml in 133 patients (troponin T positive group) and lower in 213 patients (troponin T negative group). The relative risk (RR) and 95 percent confidence intervals (95% CI) of individual and grouped events for the troponin T positive group were 3.2 (95% CI, 1.4-7.3; p = 0.006) for death; 2.8 (95% CI, 1.43-5.51; p = 0.003) for death or myocardial infarction; and 2.8 (95% CI, 1.6-5.0; p < 0.001) for death, myocardial infarction or heart failure. Diabetes mellitus and troponin T levels > or = 0.1 ng/ml had independent prognostic value after adjusting for age, sex, and electrocardiographic changes; with RR 2.5 (95% CI, 1.01-5.9) for death, myocardial infarction or heart failure.

CONCLUSIONS

The prognosis of patients hospitalized for chest pain who do not immediately develop transmural necrosis depends on serum troponin T levels at hospital admission. Troponin T levels > or = 0.1 ng/ml almost triple the risk of major events in the three months after the acute episode. The prognostic value of troponin T is independent of age, sex, presence of diabetes mellitus, and electrocardiographic changes.

The determinants of activated partial thromboplastin time, relation of activated partial thromboplastin time to clinical outcomes, and optimal dosing regimens for heparin treated patients with acute coronary syndromes: a review of GUSTO-IIb

CONTEXT

Unfractionated heparin remains widely utilized in the treatment of acute coronary syndromes (ACS). However, limited data exist on optimal dosing and range of activated partial thromboplastin time (aPTT) in this setting. A large trial of thrombolysis for acute myocardial infarction has reported an association between longer aPTTs and adverse outcomes.

OBJECTIVES

Estimate the optimal heparin-dosing regimen in achieving early therapeutic aPTTs (50 to 75 seconds) and determine the association of aPTT and death, reinfarction, and bleeding in population with ACS.

DESIGN

Subgroup analysis within a randomized, controlled trial of 5861 patients given unfractionated heparin who had aPTTs at 6, 12, or 24 hours, with outcome analyses by weight categories.

SETTING

In 373 hospitals in 13 countries from May 1994 to October 1995.

PATIENTS

A total of 12142 patients admitted for ACS, stratified by the presence (n = 4131) or absence (n = 8011) of ST-segment elevation, and randomized to 72 hours of unfractionated heparin.

RESULTS

In a simulated weight-adjusted model, based on retrospective grouping by weight, a simulated dose of 60-U/kg bolus and 12-U/kg/h infusion resulted in the highest proportion of therapeutic aPTTs. After adjustment for baseline variables, longer 12-hour aPTT was associated with the composite of 30-day death or reinfarction in patients not treated with thrombolytic therapy (odds ratio, 1.10; 95% CI, 1.00 to 1.22; P = 0.047). Longer aPTT at 6 hours was associated with increased moderate or severe bleeding for the entire cohort. There was also a significant, nonlinear correlation of the 12-hour aPTT with moderate or severe bleeding in thrombolysis-treated patients.

CONCLUSIONS

For ACS patients who are treated with heparin, aPTT is highly associated with body weight. Longer aPTT within the first 12 hours is associated with adverse outcomes in ACS. Heparin dosing for ACS should be weight based.

The influence of diabetes mellitus on late clinical outcomes following coronary stent implantation

Diabetic patients have a higher restenosis rate and late morbidity following balloon angioplasty. However, the increased risk of restenosis after coronary stent implantation in diabetic patients is controversial. We compared the quantitative coronary angiographic (QCA) variables between 42 diabetic patients and 71 non-diabetic patients undergoing coronary stent implantation and for 6 months follow-up. Pre-procedural variables were identical in the diabetic and non-diabetic patients. The stent-artery ratio was lower (1.07+/-0.13 vs. 1.13+/-0.13, P=0.020), and acute gain after coronary stenting was lower (1.58+/-0.53 vs. 1.77+/-0.48, P=0.049) in the diabetic patients than in the non-diabetic patients. However, the late lumen loss (0.42+/-0.64 vs. 0.49+/-0.69), loss index (0.28+/-0.49 vs. 0.28+/-0.45), restenosis rate (19 vs. 23%) and target lesion revascularization rate (17 vs. 18%) after 6 months were identical in the diabetic and non-diabetic patients. These results suggest that diabetes itself does not increase stent restenosis.

Coronary stenting in diabetic patients: Results from the ROSETTA registry

OBJECTIVE

Diabetes mellitus is associated with high rates of restenosis and adverse outcomes after percutaneous transluminal coronary angioplasty (PTCA). It is unclear whether coronary stenting reduces adverse events in diabetic patients after PTCA. Our purpose was to determine whether coronary stenting improves clinical event rates in diabetic patients after PTCA.

METHODS

The Routine Versus Selective Exercise Treadmill Testing After Angioplasty (ROSETTA) registry was a prospective multicenter observational study examining functional testing and adverse outcomes after successful PTCA.

RESULTS

Among the 791 patients enrolled, 180 were diabetic. A total of 90 diabetics received stents while the remaining 90 patients did not. Baseline clinical characteristics were similar between the 2 groups of patients. However, patients with stents were more likely to have complex lesions, whereas those without stents were more likely to undergo atherectomy and have greater residual coronary stenosis. At 6-month follow-up, the composite end point defined as cardiac death, unstable angina, myocardial infarction, need for repeat PTCA, or coronary artery bypass graft surgery (CABG) occurred in 25.0% of stented and 22.2% of nonstented diabetic patients (P not significant [NS]). A multivariate logistic regression analysis showed that coronary stenting was not associated with a reduced incidence of the composite end point among diabetic patients (odds ratio 0.97, 95% CI 0.46-2.05, P NS).

CONCLUSION

Coronary stenting does not improve clinical event rates in diabetic patients after PTCA.

The healing process of infarct-related plaques. Insights from 18 months of serial angioscopic follow-up

OBJECTIVES

To clarify the healing process of disrupted culprit plaques of acute myocardial infarction (MI), we serially observed the culprit plaques for 18 months after the onset of acute MI by angioscopy.

BACKGROUND

Although it has been reported that disruption of the yellow plaque and subsequent thrombosis cause acute MI and that the thrombogenicity of the plaque lasts for a month, the healing process of the plaque after disruption has not been clarified.

METHODS

Eighty-five patients with acute MI were prospectively and consecutively enrolled. Angioscopic studies were performed immediately and at 1, 6 and 18 months after successful reperfusion. The prevalence of yellow plaques and thrombus was examined. The color grade of the plaque was determined as 0 (white), 1 (light yellow), 2 (yellow) or 3 (bright yellow).

RESULTS

Although yellow plaque was present at the culprit lesion in most patients throughout follow-up, its color grade was reduced from one to six months (1.9 +/- 0.6 vs. 1.1 +/- 0.7, p = 0.0003) after reperfusion, especially in the patients without hyperlipidemia (HL). The incidence of thrombus was 92.5% immediately after reperfusion, which was reduced significantly to 63.8%, 4.8% and 11.8% at 1, 6 and 18 months, respectively. The incidence of thrombus (77.8% vs. 45.0%, p = 0.03) at one month was higher in the patients with diabetes mellitus (DM).

CONCLUSIONS

The healing process of yellow plaques at the culprit lesions of MI was detected by angioscopy as reductions of color grade and thrombogenicity at six months and partially at one month after the onset of acute MI. This healing process appears to deteriorate by complicating cases of DM or HL.

Comparison of immediate and one-year outcome after coronary angioplasty of narrowing < 3 mm with those > or =3 mm ( the National Heart, Lung, and Blood Institute Dynamic Registry)

Balloon angioplasty of small coronary artery lesions has been associated with lower success and higher complication rates than large coronary artery lesions. This study evaluates the in-hospital and 1-year outcome of the treatment of small coronary artery lesions in the modern era of interventional cardiology and compares it with the outcome of treating large coronary artery lesions. Of 1,658 patients with a single lesion treated from July 1997 to February 1998 in the National Heart, Lung, and Blood Institute (NHLBI) Dynamic Registry, there were 587 patients with small coronary artery lesions (<3 mm) and 1,071 patients with large coronary artery lesions (> or =3 mm). Success, in-hospital, and 1-year outcomes between both groups were compared. Patients with lesions in small coronary arteries were more often women, insulin-treated diabetics, and had undergone more prior coronary bypass graft surgery. Conventional angioplasty alone was performed more often and angioplasty with stents was performed less often in the small coronary artery than in the large coronary artery group. Angiographic success was slightly lower in the small coronary artery group (94.2% vs 96.9%, p <0.05). Periprocedural and in-hospital complication rates were similar in both groups. Likewise, at 1-year follow-up, major adverse cardiac events including death, myocardial infarction, and coronary artery bypass graft surgery were relatively low and comparable between the 2 groups, although patients with small coronary arteries were more likely to undergo repeat revascularization (17.4% vs 13.6%, p <0.05). Treatment of lesions in small coronary arteries in the modern era is associated with high success and low complication rates, comparable to the treatment of large coronary artery lesions, although the incidence of repeat revascularization was significantly greater at follow-up even if stents were used.

Histopathologic validation of in-vivo angioscopic observation of coronary thrombus after angioplasty in a porcine model

BACKGROUND

Coronary angioscopy has been reported to be superior to angiography and intravascular ultrasound for detecting intracoronary thrombus. However, in-vivo histopathologic validation of angioscopic detection of intracoronary thrombus had not been performed.

OBJECTIVE

To perform histopathologic validation of in-vivo angioscopic detection of coronary thrombus.

DESIGN

An experimental, blinded comparison of angioscopy and histopathology.

METHODS

Coronary angioscopy was performed from 0 to 14 days after angioplasty in 39 porcine coronary arteries. When thrombus was detected by angioscopy, it was subclassified into white, mixed red-white, or red thrombus according to color. By histopathology the presence of thrombus was determined and subclassified into platelet-rich, mixed platelet-erythrocyte, or erythrocyte-rich thrombus.

RESULTS

Angioscopy correctly classified 19 of 21 coronary thrombi (sensitivity 90%) but incorrectly classified nine of 18 arteries without formation of thrombus as having a thrombus (specificity 50%). Positive and negative predictive values were 68 and 82%, respectively. The angioscopic subclassification of thrombus into white, mixed red-white, or red thrombi was not correlated to the corresponding histopathologic morphology (platelet-rich, mixed platelet-erythrocyte, or erythrocyte-rich) of the observed thrombi (chi2 test: P = 0.5).

CONCLUSIONS

Angioscopic detection of thrombus in vivo had high sensitivity and negative predictive value but low-to-moderate specificity and positive predictive value. Visual assessment of color of angioscopically detected thrombi seemed not to reflect histopathologic morphology of thrombus according to the definitions used in the present study.

Impaired modulation of circadian rhythms in patients with diabetes mellitus: a risk factor for cardiac thrombotic events?

Serious adverse cardiovascular events, including myocardial infarction, sudden cardiac death, and stroke, frequently result from rupture of atherosclerotic plaques with superimposed thrombosis and exhibit a pronounced circadian rhythmicity, peaking in the morning hours. Two potentially synergistic mechanisms play a pathogenic role in the circadian variation of arterial thrombotic events. A morning surge in sympathetic activity alters hemodynamic forces and predisposes vulnerable coronary atherosclerotic plaques to rupture. Day-night variations of hemostatic and fibrinolytic factors result in morning hypercoagulability and hypofibrinolysis, promoting intraluminal thrombus formation at the same time when the risk for plaque rupture is highest. Diabetic patients have a very high cardiac event rate but fail to show normal circadian fluctuations in the occurrence of myocardial infarction. Alterations in the circadian variation autonomic tone, blood pressure, and the thrombotic-thrombolytic equilibrium have been documented in diabetic patients. These include reduced or absent 24-h periodicity in autonomic tone, fibrinolytic activity, and thrombotic tendency, and a blunted decline in nocturnal blood pressure. Disruption of these circadian rhythms explains the lack of significant circadian distribution of cardiac events in diabetic patients. Moreover, the loss of these normal biorhythms results in a continuous susceptibility to thrombotic events throughout the day and may contribute to the excess cardiovascular mortality and morbidity in these patients.

Issues and challenges with antithrombotic therapy in diabetic patients with acute coronary syndromes

Diabetes mellitus is associated with significant morbidity and mortality in the setting of acute coronary syndromes. This increased risk is attributable, in large part, to the derangements in coagulation that can accompany the diabetic disease state. Patients with diabetes mellitus have disturbances in endothelial function, platelet function, and coagulation factors. Until recently, there has been little direct exploration of therapeutic measures to improve outcome specifically among diabetic patients with acute coronary syndromes. Fortunately, antithrombotic therapies that have proven benefit in the general population also seem to be beneficial among patients with diabetes, although optimal dosing for improved safety and efficacy in this population has yet to be established for many of these agents. Primary prevention strategies and strict attention to risk factor modification hold the greatest promise for improving long-term outcome.

Management of coronary artery disease: therapeutic options in patients with diabetes

OBJECTIVES

The aim of this review is to discuss the particularities of coronary artery disease (CAD), the effect of intensive medical management and the outcome of percutaneous and surgical revascularization in patients with diabetes mellitus (DM).

BACKGROUND

CAD represents the leading cause of death in patients with DM. Numerous clinical, biological and angiographic risk factors have been shown to be associated with CAD in diabetic patients.

METHODS

Metabolic abnormalities in patients with DM including insulin resistance, hyperglycemia and dyslipidemia are briefly discussed. Then the potential roles of medical management and of percutaneous and surgical coronary revascularization are more extensively reviewed.

RESULTS

More vigorous control of hyperglycemia, hyperlipidemia, hypertension and other risk factors may be of crucial importance for risk reduction. Despite remarkable progress in recent years, the choice of a coronary revascularization strategy remains a challenge in these patients. Diabetic patients with CAD are predisposed to higher cardiovascular events after balloon angioplasty. Whether stenting and new antiplatelet drugs improve the results of percutaneous revascularization in this population needs further evaluation. The superiority of the surgical approach is also not definitely established. Therefore, many aspects of coronary revascularization are still unclear in these patients.

CONCLUSIONS

The results of ongoing randomized trials comparing multiple coronary stents to bypass surgery will likely provide some answers to our questions and additional randomized trials evaluating intensive diabetic control with or without coronary revascularization are needed to determine the best therapeutic approach in these patients.

Diabetes mellitus and outcome after primary coronary angioplasty for acute myocardial infarction: lessons from the GUSTO-IIb Angioplasty Substudy. Global Use of Strategies to Open Occluded Arteries in Acute Coronary Syndromes

OBJECTIVES

We sought to compare the efficacy of primary angioplasty in diabetics versus nondiabetics and to evaluate the relative benefits of angioplasty over thrombolytic therapy among diabetics.

BACKGROUND

Primary angioplasty for myocardial infarction is at least as effective as thrombolytic therapy in the general population. However, the influence of diabetic status on outcome after primary angioplasty versus thrombolysis remains unknown.

METHODS

Patients in the Global Use of Strategies To Open Occluded Arteries in Acute Coronary Syndromes (GUSTO-IIb) Angioplasty Substudy were randomized to receive either primary angioplasty or accelerated alteplase. The interaction of diabetic status (diabetics n = 177, nondiabetics n = 961) and treatment strategy with the occurrence of the primary end point (death, nonfatal reinfarction or nonfatal, disabling stroke at 30 days) was analyzed (power to detect a 40% relative reduction in the primary end point with alpha = 0.05 and beta = 0.20). Among patients who were randomized to and underwent primary angioplasty, procedural success (defined as residual stenosis <50% and TIMI grade 3 flow) was assessed based on diabetic status.

RESULTS

Compared with nondiabetics, diabetics had worse baseline clinical and angiographic profiles. Despite more severe stenosis and poorer flow in the culprit artery, procedural success with angioplasty was similar for diabetics (n = 81; 70.4%) and nondiabetics (n = 391; 72.4%). Outcome at 30 days was better for nondiabetics randomized to angioplasty versus alteplase (adjusted odds ratio, 0.62; 95% confidence interval, 0.41-0.96) with a similar trend for diabetics (0.70, [0.29-1.72]). We noted no interaction between diabetic status and treatment strategy on outcome (p = 0.88).

CONCLUSIONS

Primary angioplasty was similarly successful in diabetics and nondiabetics and appeared to be more effective than thrombolytic therapy among diabetics with acute infarction.

Comparison of coronary stent expansion by intravascular ultrasonic imaging in younger versus older patients with diabetes mellitus

The poor long-term outcome in young diabetic patients receiving stents is not well understood. The purpose of this study was to characterize the pastprocedural results of stent placement in diabetic patients using intravascular ultrasound to identify factors that might be associated with poor clinical outcome. The acute dimensions from intravascular ultrasound studies after stent deployment at 5 sites were measured from 39 coronary segments from patients with diabetes mellitus (DM) and 161 segments from nondiabetic patients (non-DM). Within these 2 groups, segments were subgrouped into young (y) and old (o) in reference to the mean study age of 64 years, forming 4 groups: yDM (n = 20), y non-DM (n = 65), oDM (n = 19), and o non-DM (n = 96). Results are reported as mean +/- 1 SD. Diabetic patients had smaller mean lumen area within the treated segment than o non-DM (8.37+/-2.59 vs. 9.11+/-3.35 mm2, p<0.01). These differences were more pronounced at the distal reference vessel lumen of yDM than y non-DM (7.6+/-2.3 vs. 10.3+/-4.5 mm2, p<0.003), and were associated with greater percent plaque area in the distal reference vessel (43.4+/-13% vs. 34.1+/-11.2%, p<0.003). In young diabetic patients undergoing elective stent placement, underexpansion of the stented segment is common, which may contribute to the relatively poor long-term outcome in these patients. We suggest that when stenting is the procedure of choice in this subgroup of high-risk patients, special attention should be given to optimizing lumen dimensions.

Can dobutamine stress echocardiography predict cardiac events in nonrevascularized diabetic patients following acute myocardial infarction?

STUDY OBJECTIVE

To determine whether the prognostic value of dobutamine stress echocardiography (DSE) performed early after acute myocardial infarction (AMI) is as high in diabetic patients as in nondiabetic patients.

DESIGN

Inception cohort study.

SETTING

Tertiary cardiac referral center.

PATIENTS AND INTERVENTIONS

Three hundred thirty-eight patients (116 diabetic and 222 nondiabetic) who underwent DSE after AMI were followed up for cardiac events.

MEASUREMENTS AND RESULTS

Outcome events were as follows: "hard" events consisted of cardiac death and nonfatal reinfarction, while "all events" included hard events and unstable angina. The mean follow-up duration was 21 +/- 9 months. DSE results were positive in 69 diabetic patients (59.5%) and 129 nondiabetic patients (58.1%; p = 0.817). During the follow-up period, there were 25 cardiac deaths, 16 cases of nonfatal reinfarction, and 55 cases of unstable angina. The Kaplan-Meier life table showed that a positive DSE result was associated with a lower event-free survival rate in nondiabetic but not in diabetic patients in terms of hard and all events. By multivariate analysis, a positive DSE result was the strongest independent predictor of future cardiac events in nondiabetic patients. However, in diabetics, a shorter dobutamine time, rather than a positive DSE result, independently predicted cardiac events.

CONCLUSIONS

Our preliminary data suggest that different DSE variables should be considered when assessing the likelihood of future events in diabetic and nondiabetic patients after AMI. The observation of shorter dobutamine time, instead of DSE positivity, has a higher prognostic value in diabetics. In diabetic patients, the only significant role of DSE positivity is for predicting future unstable angina; however, its predictive value is not as good as in nondiabetic patients.

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.

Circadian patterns of heart rate variability, fibrinolytic activity, and hemostatic factors in type I diabetes mellitus with cardiac autonomic neuropathy

Diabetes mellitus is associated with a marked increase in the risk of coronary events but with an altered circadian distribution that demonstrates an absent morning peak and higher infarction rate during the evening hours. To elucidate the mechanism of this phenomenon, the circadian pattern of heart rate variability was evaluated in 22 type I diabetic patients with diabetic autonomic neuropathy in conjunction with circadian changes of fibrinolytic and hemostatic factors. The circadian pattern (6 A.M. to 10 P.M. vs 10 P.M. to 6 A.M.) of 3 indexes of parasympathetic tone was evaluated using 24-hour heart rate variability analysis. The high-frequency power (3.0 +/- 0.2 vs 3.3 +/- 0.2 ms2, p = 0.08) and the percentage of RR intervals with >50 ms variation (0.47 +/- 0.18 vs 0.69 +/- 0.33 ms, p = 0.52) demonstrated no significant circadian variation. The square root of mean squared differences of successive RR intervals showed a small but significant increase during nighttime (8.5 +/- 0.7 vs 9.7 +/- 1.1 ms, p = 0.02). Fibrinolytic activity was significantly lower at 8 A.M. than at 4 P.M. (166.4 +/- 12.5 to 200.2 +/- 9.3 mm2, p = 0.0003), but with a low amplitude. Plasminogen activator inhibitor 1 showed no circadian variation. Factor VII and fibrinogen demonstrated a significant reduction from 8 A.M. to 4 P.M., but both peak and nadir values were elevated. The von Willebrand factor was markedly elevated with no circadian variation. Thus, diabetic autonomic neuropathy is associated with a loss of both the nocturnal predominance of parasympathetic activity and a prothrombotic state that persists throughout the day. These abnormalities may attenuate the relative protection from coronary events during the afternoon and nighttime.

Restenosis, late vessel occlusion and left ventricular function six months after balloon angioplasty in diabetic patients

OBJECTIVES

We studied angiographic outcome and its predictors after traditional coronary balloon angioplasty in diabetics. We further examined whether changes in ejection fraction were influenced by the status of the dilated site(s) at follow-up.

BACKGROUND

Recent studies have suggested that diabetics have a particularly poor outcome after balloon angioplasty. The reasons for this observation are not known.

METHODS

We investigated procedural and six-month angiographic outcome, analyzed by quantitative coronary angiography, and left ventricular function in 485 consecutive diabetics (627 lesions) treated by balloon angioplasty without stent implantation.

RESULTS

The procedure was successful in 455 (94%) patients; angiographic follow-up was available in 377 patients (83%). At follow-up, the rates of restenosis and total occlusion were 62% and 13%, respectively. Five independent predictors of restenosis were identified: the presence of organ damage, a saphenous vein graft (SVG) angioplasty, a bifurcation lesion, a Thrombolysis in Myocardial Infarction (TIMI) flow <3 preprocedure and the degree of residual stenosis. Four independent predictors of vessel occlusion were identified: treatment with insulin, a SVG angioplasty, a TIMI flow <3 preprocedure and the degree of residual stenosis after angioplasty. Late vessel occlusion at angioplasty site(s) was observed in 15% of patients, ranging from 11% for a one-site procedure to 37% for a three-site procedure. This complication was associated with a decrease in ejection fraction at follow-up (-6.2 +/- 9.9%, p = 0.0001), whereas no significant change was observed in patients without occlusion.

CONCLUSIONS

This study shows that late vessel occlusion is a frequent mode of restenosis in diabetic patients and is associated with a significant decrease in ejection fraction. This could partly explain the poor long-term clinical outcome reported in such patients after traditional balloon angioplasty.

Arterial remodelling of native human coronary arteries in patients with unstable angina pectoris: a prospective intravascular ultrasound study

OBJECTIVE

To investigate the use of intravascular ultrasound (IVUS) in detecting the presence of arterial remodelling in patients with unstable angina.

DESIGN

Prospective case study.

PATIENTS

60 of 95 consecutively admitted patients with unstable angina (41 male, 19 female), mean (SD) age 61.2 (8.1) years.

INTERVENTIONS

Qualitative and quantitative coronary angiography and IVUS.

MAIN OUTCOME MEASURES

Adaptive or constrictive remodelling (AR, CR) was considered present when the cross sectional area of the external elastic membrane at the lesion site was larger than the proximal cross sectional area or smaller than the distal cross sectional area, respectively.

RESULTS

22 of the 60 patients (37%) showed AR and 14 (23%) showed CR. No remodelling was seen in 24 patients (group NR). The plaque contained more thrombus and plaque rupture in group AR than in groups CR and NR (thrombus: 91% v 50% and 67%, respectively, p = 0.023; rupture: 73% v 29% and 42%, p = 0.020). AR was associated with a larger plaque cross sectional area (12.6 (SD 4.6) mm2 v 10.8 (6.3) and 9.2 (3.7) mm2, p = 0.001) and larger external elastic membrane cross sectional area (16.5 (5.8) mm2 v 13.2 (5.2) and 14.4 (3.6) mm2, p = 0.01 in group AR v groups CR and NR, respectively), while the plaque burden was larger in groups AR (74.9 (9.1)%) and CR (72.4 (16.6)%) than in group NR (66.2 (18.1)%, p = 0.005).

CONCLUSIONS

IVUS is capable of detecting adaptive and constrictive remodelling of target lesions and its relation to plaque morphology in unstable angina.

Implications of small reference vessel diameter in patients undergoing percutaneous coronary revascularization

OBJECTIVES

The purpose of this study was to determine whether small reference diameter of the culprit coronary artery influences the outcome of an attempted percutaneous revascularization procedure in the current era of interventional cardiology.

BACKGROUND

Although the interventional strategy is largely determined by the size of the culprit coronary artery, earlier quantitative studies have not shown a worse acute outcome for small reference vessel diameter (< or =2.5 mm).

METHODS

A total of 2,306 patients undergoing percutaneous coronary revascularization was divided in groups with reference diameters < or =2.5 mm (n = 813) or >2.5 mm (n = 1,493). Success and in-hospital major adverse cardiac event (death, Q-wave myocardial infarction and emergency coronary artery bypass graft) rates between both groups were compared.

RESULTS

Patients with lesions in small vessels were older and presented more frequently with female gender, diabetes mellitus, heart failure, peripheral vascular, multivessel coronary disease and American Heart Association/American College of Cardiology (AHA/ACC) lesion type C (p < or = 0.01, each). Further, utilization of interventional devices differed markedly. In contrast to stents (18.5% vs. 41.9%) and directional atherectomy (3.7% vs. 13.5%), conventional balloon angioplasty (73% vs. 50%) and rotational atherectomy (16.1% vs. 8.3%) were used more often in smaller vessels (p < or = 0.0001, each). Success rate was lower in the small vessel group (92% vs. 95%; p = 0.006). Major adverse cardiac events occurred more frequently in small than large vessels (univariate 3.4% vs. 2.0%, p = 0.03; multivariate odds ratio 2.1, p = 0.02), particularly when proximal coronary segments were compared.

CONCLUSIONS

Lesions in vessels with small reference diameter represent a distinct group with respect to clinical and morphologic characteristics as well as device utilization. These lesions have lower chances of successful percutaneous intervention and carry relatively higher risks, specifically when located in proximal coronary segments.

Interesting cases from the University of Texas Medical Branch

This article discusses the cases for four patients with unstable angina. The first case is an example of the "high-risk" patient with widespread ECG changes, heart failure, and enzymatic elevations during an episode of chest pain. The second patient illustrates an unusual cause of unstable angina in a young women. The third patient had a large thrombus visible on angiography and management strategies for dealing with intracoronary thrombus are discussed. The final patient had an extensive past cardiac history with two prior coronary artery bypass operations and we discuss the recent advances made in the treatment of degenerative vein graft disease.

Glycoprotein IIb/IIIa inhibitors in acute coronary syndromes: pathophysiologic foundation and clinical findings

The pathophysiologic basis for potent platelet inhibition in the acute coronary syndromes has been established. In the setting of PTCA for unstable angina and non-Q-wave myocardial infarction, there are clear data for a benefit of GP IIb/IIIa inhibition, whereas for primary PTCA in evolving myocardial infarction, preliminary data are very encouraging and a large-scale clinical trial is nearly completed. Glycoprotein IIb/IIIa inhibition as an adjunct to medical therapy for unstable angina is also the subject of encouraging preliminary data, and 3 large-scale clinical trials have just been completed. Preliminary data have also been accrued for GP IIb/IIIa inhibition as conjunctive therapy with thrombolytic agents, and large clinical trials are now commencing.

Angioscopy of culprit coronary lesions in unstable angina pectoris and correlation of clinical presentation with plaque morphology

This study demonstrates that plaque disruption and thrombus are absent in a considerable number of patients with unstable angina and that culprit lesion morphologies as assessed by angioscopy may differ among the various clinical subsets of patients. Although plaque disruption and thrombus undoubtedly play an important role in the pathogenesis of unstable angina, alternative mechanisms may be responsible for ischemia in some patients.

Coronary risk factors and plaque morphology in men with coronary disease who died suddenly

BACKGROUND

Cigarette smoking and abnormal serum cholesterol concentrations are risk factors for acute coronary syndromes, but the underlying mechanisms are poorly understood. We studied whether cigarette smoking and abnormal cholesterol values may precipitate acute coronary thrombosis and sudden death resulting from either rupture of vulnerable coronary plaques or erosion of plaques.

METHODS

We examined the hearts of 113 men with coronary disease who had died suddenly and also analyzed their coronary risk factors. We found an acute coronary thrombus in each of 59 men, and severe narrowing of the coronary artery by an atherosclerotic plaque without acute thrombosis (stable plaque) in 54. Cases of acute thrombosis were divided into two groups: 41 resulting from rupture of a vulnerable plaque (a thin fibrous cap overlying a lipid-rich core), and 18 resulting from the erosion of a fibrous plaque rich in smooth-muscle cells and proteoglycans. Vulnerable plaques that had not ruptured were counted in each heart.

RESULTS

Cigarette smoking was a risk factor in 44 (75 percent) of the men with acute thrombosis, as compared with 22 (41 percent) of the men with stable plaques (P<0.001). The mean (+/-SD) ratio of serum total cholesterol to high-density lipoprotein (HDL) cholesterol was markedly elevated in the men who died of acute thrombosis with plaque rupture (mean, 8.5+/-4.0) but only mildly elevated in the men without acute thrombosis (5.5+/-2.4; P<0.001) and in the men with thrombi overlying eroded plaques (5.0+/-1.8; P<0.001). Multivariate analysis showed an association between an elevated ratio of serum total cholesterol to HDL cholesterol and the presence of vulnerable plaques (P<0.001).

CONCLUSIONS

Among men with coronary disease who die suddenly, abnormal serum cholesterol concentrations - particularly elevated ratios of total cholesterol to HDL cholesterol - predispose patients to rupture of vulnerable plaques, whereas cigarette smoking predisposes patients to acute thrombosis.

Angioscopic assessment of coronary lesions underlying thrombus

This study examines the characteristics of coronary lesions in which thrombus is found as assessed by angioscopy before percutaneous transluminal coronary angioplasty in patients with various coronary syndromes. Our findings demonstrate that the plaque underlying intracoronary thrombus is usually yellow and/or disrupted, and support in vitro observations that lipid-rich plaques are highly thrombogenic and that disruption of these plaques is associated with in situ thrombosis.

Correlation of angiographic morphology and clinical presentation in unstable angina

OBJECTIVES

This study sought to correlate angiographically detected complex lesions and intracoronary thrombus with the severity of clinical presentation in unstable angina (UA).

BACKGROUND

Unstable angina is usually related to acute thrombosis superimposed on a disrupted plaque. Complex and thrombotic lesions are more prevalent in UA and have been associated with a worse prognosis. The highest levels of the Braunwald classification of UA (III = rest angina within 48 h of presentation; C = postinfarction angina; and c = angina refractory to maximal medical therapy) can be used to assess the severity of clinical presentation, but they have not been directly correlated with thrombotic and complex lesions.

METHODS

We conducted a prospective study of 284 patients with UA who underwent cardiac catheterization. A single angiographer with no knowledge of the clinical classifications interpreted all angiograms. Culprit lesions identified in 200 patients were classified as simple or complex. Complex lesions included the categories complex morphology, intracoronary thrombus (ICT) or total occlusion. Lesions were also quantitatively analyzed, and Thrombolysis in Myocardial Infarction (TIMI) flow was assessed. Univariate and multivariate logistic regression analyses of the angiographic findings were performed controlling for all cardiac risk factors, previous angioplasty or bypass surgery and multivessel disease, and we sequentially compared Braunwald classes III, C and c with classes < III, < C and < c, respectively.

RESULTS

Class III was associated with complex lesions (p = 0.04) and decreased TIMI flow (p = 0.03). Class C angina correlated with complex lesions (p = 0.04), ICT (p = 0.005) and decreased TIMI flow (p = 0.03). Class c angina was associated with ICT (p = 0.02). The degree of stenosis by quantitative angiography was not associated with any particular Braunwald class.

CONCLUSIONS

Recent rest pain and refractory or postinfarction UA, or both, are strongly associated with the general category of complex lesions and specifically with angiographically detected ICT and decreased TIMI flow.