Using troponin T to diagnose acute coronary syndromes

Elevated troponin T is a useful marker for acute myocardial infarction: it is more specific than is elevated creatine kinase MB isoenzyme, and it remains elevated for many days after creatine kinase levels have returned to normal, providing a useful indicator for late presentations. Nevertheless, creatine kinase MB still has many important roles, including providing estimates of infarct size and diagnosing acute myocardial infarction in patients with renal failure. Often, measuring both markers provides additional information. This article provides a diagnostic algorithm for using both markers.

In vitro effects of beta-hydroxy-beta-methylbutyrate (HMB) on cell-mediated immunity in fish

beta-Hydroxy-beta-methyl butyrate(HMB) has been shown to counteract many of the negative effects of intensive animal production methods and results in increased growth and protection against diseases. In the present study, the effect of HMB on the immunocompetence cell activity in rainbow trout (Oncorhynchus mykiss) and carp (Cyprinus carpio) was examined. Pronephric phagocytes and lymphocytes were isolated from the fish and grown in culture medium (RPMI-1640) containing either 0, 0.1, 1, 5, 10, 25, 50 or 100 microg HMB/ml of medium. The effects of HMB on the respiratory burst activity (RBA) stimulated by phorbol myristate acetate (PMA), the potential killing activity (PKA) and lymphocyte proliferation stimulated by either concanavalin A (Con-A) or lipopolysaccharide (LPS) were examined. The addition of HMB to the culture medium increased the RBA by up to 84% (p<0.01) over that of cells grown without HMB. Similarly, the PKA of the phagocytes was also increased with HMB addition to the medium by up to 140% (p<0.01) over that of cells grown without HMB. Lymphocyte proliferation stimulated by both ConA and LPS was also increased approximately two-fold (p<0.01) when HMB was added to the culture medium at concentrations between 10 and 100 microg HMB/ml in both rainbow trout and carp. The greatest effects of HMB on RBA and PKA activities were observed at a concentration >50 microg HMB/ml while lymphocyte proliferation was maximally stimulated at 25 microg HMB/ml. In conclusion, the current study shows that HMB could potentially improve immunocompetence cell activity in fish through increased cell proliferation and functionality.

The vulnerable coronary plaque

Vulnerable coronary plaques are asymptomatic atherosclerotic lesions with the tendency to rupture. Plaque rupture is the initiating event in most acute coronary syndromes including sudden cardiac death, acute myocardial infarction, and unstable angina. Vulnerable plaques are commonly found in coronary arteries at autopsy but are virtually undetectable by standard diagnostic techniques such as stress testing and coronary angiography. Using new imaging techniques, in particular intravascular ultrasound and magnetic resonance imaging (MRI), scientists are now able to identify these plaques in vivo. A better understanding of the pathophysiology of plaque vulnerability and rupture will eventually lead to the therapeutic goal of plaque stabilization in the prevention of acute coronary syndromes. This article reviews the role of plaque vulnerability in coronary artery disease. The anatomy and pathophysiology of vulnerable plaques as well as diagnostic and therapeutic implication will be described.

Nutritional supplementation of the leucine metabolite beta-hydroxy-beta-methylbutyrate (hmb) during resistance training

The effects of supplementation of the leucine metabolite beta-hydroxy-beta-methylbutyrate (HMB) were examined in a resistance training study. Thirty-nine men and 36 women between the ages of 20-40 y were randomized to either a placebo (P) supplemented or HMB supplemented (3.0 g HMB/d) group in two gender cohorts. All subjects trained three times per week for 4 wk. In the HMB group, plasma creatine phosphokinase levels tended to be suppressed compared to the placebo group following the 4 wk of resistance training (HMB:174. 4 +/- 26.8 to 173.5 +/- 17.0 U/L; P:155.0 +/- 20.8 to 195.2 +/- 23.5 U/L). There were no significant differences in strength gains based on prior training status or gender with HMB supplementation. The HMB group had a greater increase in upper body strength than the placebo group (HMB:7.5 +/- 0.6 kg; P:5.2 +/- 0.6 kg; P = 0.008). The HMB groups increased fat-free weight by 1.4 +/- 0.2 kg and decreased percent fat by 1.1% +/- 0.2% while the placebo groups increased fat-free weight by 0.9 +/- 0.2 kg and decreased percent fat by 0.5% +/- 0.2% (fat-free weight P = 0.08, percent fat P = 0.08, HMB compared to placebo). In summary, this is the first short-term study to investigate the roles of gender and training status on the effects of HMB supplementation on strength and body composition. This study showed, regardless of gender or training status, HMB may increase upper body strength and minimize muscle damage when combined with an exercise program.

[Antimicrobial efficacy of a silver layer on hydrogel lenses] Citation]

BACKGROUND

The high standard of hygiene required in using contact lenses requires regular sterilization, for which the application of a hydrogen peroxide system or storage in liquids containing antimicrobial agents are regarded as the most effective procedures. An approach to avoiding contamination could be to provide the lenses themselves with antimicrobial properties. For this purpose contact lenses equipped with a silver layer were examined for their effect on bacteria.

MATERIALS AND METHODS

The antimicrobial efficacy of a silver layer on Weflex 55 hydrogellenses (watercontent 55%, nonionic) was investigated. The lenses were incubated at 37 degrees C for 1 h in suspensions (10(8) CFU/ml) with Pseudomonas aeruginosa or Staphylococcus aureus and were rinsed afterwards. The detachment of the adherent bacteria took place by shaking the lenses in the presence of glass beads (diameter 0.5 mm). Samples of these suspensions were taken, and microbial counts were performed before and after incubation of the contaminated lenses for 6 h and 24 h in a sterile solution of sodium chloride (0.9%, w/v).

RESULTS

Lenses with a silver layer showed markedly fewer test organisms than did unprepared lenses. However, this effect was detectable only when the contaminated lenses were kept in sodium chloride solution (0.9%) for several hours. After incubation for 67 at 25 degrees C the microbial numbers of P. aeruginosa were diminished by about 4 log steps, and those of S. aureus by about 1 log step. Particularly in the case of P. aeruginosa the antimicrobial property of the silver layer was very effective. The microbial numbers of this species, which can cause serious infections of the eyes, were reduced after 24 h by more than 6 log steps. However, S. aureus showed a reduction of only 1.5 log steps. These results reflect the antimicrobial effect of silver ions which are dissolved from depots in the surfaces of the lenses only in traces because of their low dissolution properties.

CONCLUSIONS

These first investigations of preserved contact lenses indicate a new possibility for reducing lens-induced infections of the eyes. Due to the weak efficacy against the gram-positive species S. aureus a silver layer probably cannot replace other sterilization procedures completely, but it may represent an additional protection from contamination. Side effects to the eyes due to the negligible toxicity of oligodynamics silver concentrations, such are known to occur with high silver concentrations, should be not expected, but possible allergic reactions caused by the silver-ions should be investigated.

Rationale for a postintervention continuum of care: insights from intravascular ultrasound

In 1987, Glagov published a provocative hypothesis that the principal initial response to plaque accumulation was enlargement of the vessel as a whole (remodeling), which preserved luminal diameter until the lesion occupied a substantial proportion of the area within the elastic external membrane (EEM). This model has been confirmed and extended by intravascular ultrasound (IVUS) studies. Remodeling renders most atheromas invisible to angiography. In patients with single-vessel disease, the mean percent of EEM area occupied by atheroma at a segment with an angiographically normal appearance is 39%. IVUS studies further show that the disease progresses in a diffuse manner and that stenotic lesions represent only a small proportion of the total disease burden. We further know that disease can begin as early as the teenage years. Data suggest that up to 25% of individuals < 25 years old may be affected. Atherosclerotic lesions can be effectively targeted with lipid-lowering therapy. Preliminary data suggest that as plaques stabilize and become smaller, a reverse modeling occurs: the EEM area decreases but the lumen size remains unchanged. This may explain why significant reductions in cardiovascular events in clinical trials were accompanied by only modest angiographic evidence of regression. This hypothesis will be tested prospectively in the Reversal of Atherosclerosis with Lipitor (REVERSAL) study.

beta-hydroxy-beta-methylbutyrate (HMB) supplementation in humans is safe and may decrease cardiovascular risk factors

The leucine metabolite, beta-hydroxy-beta-methylbutyrate (HMB) enhances the effects of exercise on muscle size and strength. Although several reports in animals and humans indicate that HMB is safe, quantitative safety data in humans have not been reported definitively. The objective of this work was to summarize safety data collected in nine studies in which humans were fed 3 g HMB/d. The studies were from 3 to 8 wk in duration, included both males and females, young and old, exercising or nonexercising. Organ and tissue function was assessed by blood chemistry and hematology; subtle effects on emotional perception were measured with an emotional profile test (Circumplex), and tolerance of HMB was assessed with a battery of 32 health-related questions. HMB did not adversely affect any surrogate marker of tissue health and function. The Circumplex emotion profile indicated that HMB significantly decreased (improved) one indicator of negative mood (Unactivated Unpleasant Affect category, P < 0.05). No untoward effects of HMB were indicated. Compared with the placebo, HMB supplementation resulted in a net decrease in total cholesterol (5.8%, P < 0.03), a decrease in LDL cholesterol (7.3%, P < 0.01) and a decrease in systolic blood pressure (4.4 mm Hg, P < 0.05). These effects of HMB on surrogate markers of cardiovascular health could result in a decrease in the risk of heart attack and stroke. In conclusion, the objective data collected across nine experiments indicate that HMB can be taken safely as an ergogenic aid for exercise and that objective measures of health and perception of well-being are generally enhanced.

Three-dimensional reconstruction of the coronary artery wall by image fusion of intravascular ultrasound and bi-plane angiography

BACKGROUND

Intravascular ultrasound (IVUS) is becoming increasingly accepted for assessing coronary anatomy. However, its utility in visualizing and quantifying coronary morphology has been limited by its 2D tomographic nature. This study presents a 3D reconstruction technique that accurately preserves 3D geometric information.

METHODS AND RESULTS

Images obtained from manual IVUS pullbacks and continuous bi-plane angiography were fused, using angiography to reconstruct the transducer trajectory and aid in solving for the correct rotational orientation. A novel 3D active surface method automatically identified the luminal and medial-adventitial borders which, when superimposed on the transducer trajectory, could be surface-rendered for visualization and morphometry. Segmentation agreed well with manual assessment, and 3D luminal shape matched that of angiography when projected to 2D.

CONCLUSIONS

We conclude that this method provides an accurate reconstruction of the vessel's anatomy, which accounts for the true curvature of the vessel.

American College of Cardiology/European Society of Cardiology International Study of Angiographic Data Compression Phase III: measurement of image quality differences at varying levels of data compression

OBJECTIVES

We sought to investigate up to which level of Joint Photographic Experts Group JPEG) data compression the perceived image quality and the detection of diagnostic features remain equivalent to the quality and detectability found in uncompressed coronary angiograms.

BACKGROUND

Digital coronary angiograms represent an enormous amount of data and therefore require costly computerized communication and archiving systems. Earlier studies on the viability of medical image compression were not fully conclusive.

METHODS

Twenty-one raters evaluated sets of 91 cine runs. Uncompressed and compressed versions of the images were presented side by side on one monitor, and image quality differences were assessed on a scale featuring six scores. In addition, the raters had to detect pre-defined clinical features. Compression ratios (CR) were 6:1, 10:1 and 16:1. Statistical evaluation was based on descriptive statistics and on the equivalence t-test.

RESULTS

At the lowest CR (CR 6:1), there was already a small (15%) increase in assigning the aesthetic quality score indicating "quality difference is barely discernible-the images are equivalent." At CR 10:1 and CR 16:1, close to 10% and 55%, respectively, of the compressed images were rated to be "clearly degraded, but still adequate for clinical use" or worse. Concerning diagnostic features, at CR 10:1 and CR 16:1 the error rate was 9.6% and 13.1%, respectively, compared with 9% for the baseline error rate in uncompressed images.

CONCLUSIONS

Compression at CR 6:1 provides equivalence with the original cine runs. If CR 16:1 were used, one would have to tolerate a significant increase in the diagnostic error rate over the baseline error rate. At CR 10:1, intermediate results were obtained.

American College of Cardiology/ European Society of Cardiology international study of angiographic data compression phase I. The effects of lossy data compression on recognition of diagnostic features in digital coronary angiography

OBJECTIVES

This study intended to determine the effect of varying degrees of lossy Joint Photographic Experts Group (JPEG) compression on detection of coronary angiographic features. Background Compression of digital coronary angiograms facilitates playback of images and decreases cost. There are little data on the effect of compression on the accuracy of coronary angiography.

METHODS

At six centers, 71 angiographers each reviewed a set of 100 angiographic sequences. The 100 sequences were divided into four, 25-sequence subsets. Each subset of 25 was displayed either as original images or at one of three compression ratios (CRs) (6:1, 10:1 or 16:1). The effect of lossy compression on the sensitivity and specificity for detection of diagnostic features was determined. The effect of compression on subjective measures of image quality graded by the angiographers was also examined.

RESULTS

Lossy compression at a ratio of 16:1 decreased the sensitivity for the detection of diagnostic features (76% vs. 80%P=0.004). The largest effect was in the detection of calcification (52% vs. 63% at 16:1 compression vs. original images, P<0.001). Subjective indicators of image quality indicated a reduction in confidence in interpretation at CRs of 10:1 and 16:1.

CONCLUSIONS

With increased ratios of lossy compression, a degradation of digital coronary angiograms occurs that results in decreased diagnostic accuracy. The sensitivity for detection of common diagnostic features was decreased, and subjective assessment of image quality was impaired. Caution is warranted in the interpretation of coronary angiograms that have been subjected to lossy JPEG compression beyond a ratio of 6:1.

American College of Cardiology/ European Society of Cardiology international study of angiographic data compression phase III. Measurement Of image quality differences at varying levels of data compression

OBJECTIVES

We sought to investigate up to which level of Joint Photographic Experts Group (JPEG) data compression the perceived image quality and the detection of diagnostic features remain equivalent to the quality and detectability found in uncompressed coronary angiograms.

BACKGROUND

Digital coronary angiograms represent an enormous amount of data and therefore require costly computerized communication and archiving systems. Earlier studies on the viability of medical image compression were not fully conclusive.

METHODS

Twenty-one raters evaluated sets of 91 cine runs. Uncompressed and compressed versions of the images were presented side by side on one monitor, and image quality differences were assessed on a scale featuring six scores. In addition, the raters had to detect pre-defined clinical features. Compression ratios (CR) were 6:1, 10:1 and 16:1. Statistical evaluation was based on descriptive statistics and on the equivalence t -test. Results At the lowest CR (CR 6:1), there was already a small (15%) increase in assigning the aesthetic quality score indicating "quality difference is barely discernible-the images are equivalent.' At CR 10:1 and CR 16:1, close to 10% and 55%, respectively, of the compressed images were rated to be "clearly degraded, but still adequate for clinical use' or worse. Concerning diagnostic features, at CR 10:1 and CR 16:1 the error rate was 9.6% and 13.1%, respectively, compared with 9% for the baseline error rate in uncompressed images.

CONCLUSIONS

Compression at CR 6:1 provides equivalence with the original cine runs. If CR 16:1 were used, one would have to tolerate a significant increase in the diagnostic error rate over the baseline error rate. At CR 10:1, intermediate results were obtained.

American College of Cardiology/European Society of Cardiology International Study of Angiographic Data Compression Phase I: The effect of lossy data compression on recognition of diagnostic features in digital coronary angiography

OBJECTIVES

This study intended to determine the effect of varying degrees of lossy Joint Photographic Experts Group (JPEG) compression on detection of coronary angiographic features.

BACKGROUND

Compression of digital coronary angiograms facilitates playback of images and decreases cost. There are little data on the effect of compression on the accuracy of coronary angiography.

METHODS

At six centers, 71 angiographers each reviewed a set of 100 angiographic sequences. The 100 sequences were divided into four, 25-sequence subsets. Each subset of 25 was displayed either as original images or at one of three compression ratios (CRs) (6:1, 10:1 or 16:1). The effect of lossy compression on the sensitivity and specificity for detection of diagnostic features was determined. The effect of compression on subjective measures of image quality graded by the angiographers was also examined.

RESULTS

Lossy compression at a ratio of 16:1 decreased the sensitivity for the detection of diagnostic features (76% vs. 80% p = 0.004). The largest effect was in the detection of calcification (52% vs. 63% at 16:1 compression vs. original images, p < 0.001). Subjective indicators of image quality indicated a reduction in confidence in interpretation at CRs of 10:1 and 16:1.

CONCLUSIONS

With increased ratios of lossy compression, a degradation of digital coronary angiograms occurs that results in decreased diagnostic accuracy. The sensitivity for detection of common diagnostic features was decreased, and subjective assessment of image quality was impaired. Caution is warranted in the interpretation of coronary angiograms that have been subjected to lossy JPEG compression beyond a ratio of 6:1.

Assessment of coronary compensatory enlargement by three-dimensional intravascular ultrasound

Several techniques have been used to demonstrate that human arteries respond to atherosclerosis by increasing their total arterial area to prevent a decrease in blood flow. Three-dimensional reconstructions of coronary arteries can document this compensatory response accurately and specifically. Seven human coronary arteries were reconstructed using intravascular ultrasound and biplane angiography, and vessel geometries were quantified. In all seven vessels, as plaque area increased, overall vessel area increased (R = 0.986, 0.933, 0.984, 0.678, 0.763, 0.963, and 0.830), but luminal cross-sectional area did not significantly decrease. Focal compensatory enlargement was identified in each vessel, and in some cases this response appeared to occur until the vessel was 65% occluded. Luminal enlargement near the proximal ends was attributed to the natural taper of the vessel. The semi-automated, three-dimensional segmentation technique used in this study allows reproducible quantification, as there is no subjective manual tracing involved. Following the intravascular ultrasound transducer in time and space with biplane angiography allows for accurate reconstruction with or without automated pullback devices. Information on the rate of change of vessel measurements is also presented, which, when combined with visualization of accurate 3D geometry, provides a unique assessment of coronary compensatory enlargement. This reconstruction technique can be applied in a clinical environment with no major modification.

Prediction of short- and long-term outcomes by troponin T levels in low-risk patients evaluated for acute coronary syndromes

STUDY OBJECTIVE

Recent reports suggest a short series of cardiac troponin (cTnT) testing effectively identifies patients at risk for cardiac events. However, there are few studies validating this strategy. The purpose of this study was to determine the ability of cTnT levels to predict short- and long-term outcomes in low-risk patients with suspected acute coronary syndromes.

METHODS

This prospective longitudinal study was conducted in a 20-bed emergency department observation unit. Patients at low risk for acute coronary ischemia, with a normal creatine kinase-isoenzyme subunit MB (CKMB) index, were admitted to an observation unit for chest pain evaluation. Serum cTnT levels were measured at baseline and at 4, 8, and 16 hours after admission. The main outcome measures were adverse cardiac events (death, acute myocardial infarction, unstable angina, revascularization) during the index visit and within 6 months after discharge. Using manufacturer's recommendations, the cTnT level was considered abnormal if it exceeded 0.2 microg/L.

RESULTS

Two hundred sixty-six patients were evaluated. Twenty-one (7.9%) had an adverse event during their index hospitalization. Troponin testing identified only 2 (9.5%) of these patients. Twenty (7.5%) had a cardiac event within 6 months; none were identified by cTnT testing. The sensitivity and specificity were 9.5% and 99.2%, respectively, at the index visit, and 0% and 98.4% at 6 months. The positive and negative predictive values were 50% and 93%, respectively, at the index visit; and 0% and 92% at 6 months.

CONCLUSION

Determination of troponin T levels has a low sensitivity and high specificity for predicting outcomes in low-risk patients evaluated for suspected acute coronary syndromes. This study does not support a strategy of relying solely on troponin testing for disposition decisions.

Extent and direction of arterial remodeling in stable versus unstable coronary syndromes : an intravascular ultrasound study

BACKGROUND

The morphological characteristics of coronary plaques in patients with stable versus unstable coronary syndromes have been described in vivo with intravascular ultrasound, but the relationship between arterial remodeling and clinical presentation is not well known.

METHODS AND RESULTS

We studied 85 patients with unstable and 46 patients with stable coronary syndromes using intravascular ultrasound before coronary intervention. The lesion site and a proximal reference site were analyzed. The remodeling ratio (RR) was defined as the ratio of the external elastic membrane (EEM) area at the lesion to that at the proximal reference site. Positive remodeling was defined as an RR >1.05 and negative remodeling as an RR <0.95. Plaque area (13.9+/-5.5 versus 11.1+/-4.8 mm(2); P=0.005), EEM area (16.1+/-6.2 versus 13.0+/-4.8 mm(2); P=0. 004), and the RR (1.06+/-0.2 versus 0.94+/-0.2; P=0.008) were significantly greater at target lesions in patients with unstable syndromes than in patients with stable syndromes. Positive remodeling was more frequent in unstable than in stable lesions (51. 8% versus 19.6%), whereas negative remodeling was more frequent in stable lesions (56.5% versus 31.8%) (P=0.001).

CONCLUSIONS

Positive remodeling and larger plaque areas were associated with unstable clinical presentation, whereas negative remodeling was more common in patients with stable clinical presentation. This association between the extent of remodeling and clinical presentation may reflect a greater tendency of plaques with positive remodeling to cause unstable coronary syndromes.

Comparison of troponin T versus creatine kinase-MB in suspected acute coronary syndromes

Limitations of creatine kinase-MB (CK-MB) have led to alternative biochemical markers, including troponin T (TnT), to detect myocardial necrosis. Limited data are available regarding the predictive value of this new marker in patients with chest pain of uncertain etiology. Therefore, we prospectively compared CK-MB and TnT in a broad population with suspected acute coronary syndromes, including those admitted to a short-stay chest pain unit. CK-MB, quantitative TnT levels, and a rapid bedside assay were performed at 0, 4, 8, and 16 hours. Adverse events, including infarction, recurrent ischemia, coronary surgery, need for catheterization and/or intervention, stroke, congestive heart failure, or death, were identified by chart review and by follow-up phone call at 6 months. Of 707 patients, 104 were excluded for creatinine >2 mg/dl or incomplete data, leaving a total cohort of 603 patients. Coronary Care Unit admissions were 18%, intermediate care admissions were 14%, telemetry admissions is 21%, and admissions to 24-hour short-stay area were 47%. TnT (at 0.1 ng/ml) and CK-MB were positive in a similar proportion of patients (20.4% and 19.7%, respectively); however, the patients identified by TnT and CK-MB were not identical. In-hospital adverse events occurred in 37.1% with no differences in positive predictive value for the markers (p = NS). If CK-MB and TnT were negative, the early adverse event rate was 27%. No cardiac marker was positive by 16 hours in 54.9% of patients with an adverse event. Six-month follow-up was obtained in 576 of the 603 patients (95.5%). One hundred fifty-five late adverse events occurred in 134 patients (23.3%) at an average of 3.3+/-2.5 months after discharge. If both markers were negative, the late event rate was 20.2% and did not increase in patients with positive CK-MB or TnT >0.2 ng/ml. However, the late event rate was substantially higher (52.9%) in those with intermediate TnT levels of 0.1 to 0.2 ng/ml (p = 0.002). Thus, TnT is a suitable alternative to CK-MB in patients with suspected acute coronary syndromes. The rapid bedside assay is comparable to quantitative TnT and may enable early diagnosis and triage. A negative cardiac marker value (TnT or CK-MB) does not necessarily confer a low risk of complication in patients presenting with acute chest pain to an emergency department.

Intravascular ultrasound imaging after cardiac transplantation: advantage of multi-vessel imaging

BACKGROUND

Intravascular ultrasound is a sensitive tool to study transplant vasculopathy. However, there is no consensus regarding the methodology for imaging protocol. The impact of single versus multiple epicardial vessel imaging in determining the prevalence of transplant vasculopathy has not been determined. This study examines the benefit of three-vessel imaging versus one-vessel imaging in detecting transplant vasculopathy.

METHODS AND RESULTS

One hundred eleven transplant recipients with intravascular ultrasound imaging at baseline (within 2 months of transplantation) were studied: 107 at 1-year, 53 at 2-year and 41 at 3-year follow-up. A total of 222 arteries, 519 segments and 772 sites were analyzed (94 LAD, 65 LCX and 65 RCA). The prevalence of transplant vasculopathy lesions was 27%, 41% and 58% at 1 year, 39%, 55% and 71% at 2 years and 39%, 55% and 74% at 3 years for patients with one-, two- and three-vessel imaging, respectively. Single- or two-vessel disease was present in 23% (7) and 32% (10) patients with three-vessel imaging, leading to the potential mislabeling of these 17 (55%) patients as "disease free" if they underwent only single-vessel imaging.

CONCLUSIONS

Multivessel imaging is more sensitive in detecting the transplant vasculopathy lesions compared to single-vessel imaging. This important variable should be considered when designing and interpreting trials utilizing intravascular imaging derived end-point.

Application of intravascular ultrasound imaging in understanding and guiding percutaneous therapy for atherosclerotic coronary disease

Intravascular ultrasound imaging is a relatively new imaging modality that uses miniaturized ultrasound transducers, which are mounted on catheter tips and introduced into the vessel lumen to provide cross-sectional images of the vascular structure in real time. It has gained popularity rapidly among interventional cardiologists because of its ability to overcome many limitations of angiography, especially when dealing with complex anatomy and new devices for coronary revascularization. The tomographic perspective and the ability to elicit the detailed structure of the arterial wall have allowed the use of intravascular ultrasound to better understand the coronary atherosclerotic and allograft vasculopathy disease processes. The response of lesions to various interventional procedures also has been studied in detail. This review discusses the rationale, technique, methods of interpretation, and the current knowledge in the field of intravascular ultrasound imaging.

Shortcomings of coronary angiography and their implications in clinical practice

Physicians must interpret coronary angiography with caution and skepticism. Coronary angiography is considered the gold standard for defining coronary artery anatomy, diagnosing coronary artery disease, and guiding intervention. However, it does not provide functional information and may be misleading.