Assessment of the Histological Characteristics of Coronary Arterial Plaque With Severe Calcification

Integrating Computational and Biological Hemodynamic Approaches to Improve Modeling of Atherosclerotic Arteries

Atherosclerosis is the primary cause of cardiovascular disease, resulting in mortality, elevated healthcare costs, diminished productivity, and reduced quality of life for individuals and their communities. This is exacerbated by the limited understanding of its underlying causes and limitations in current therapeutic interventions, highlighting the need for sophisticated models of atherosclerosis. This review critically evaluates the computational and biological models of atherosclerosis, focusing on the study of hemodynamics in atherosclerotic coronary arteries. Computational models account for the geometrical complexities and hemodynamics of the blood vessels and stenoses, but they fail to capture the complex biological processes involved in atherosclerosis. Different in vitro and in vivo biological models can capture aspects of the biological complexity of healthy and stenosed vessels, but rarely mimic the human anatomy and physiological hemodynamics, and require significantly more time, cost, and resources. Therefore, emerging strategies are examined that integrate computational and biological models, and the potential of advances in imaging, biofabrication, and machine learning is explored in developing more effective models of atherosclerosis.

Orbital atherectomy safety and efficacy: A comparative analysis of ostial versus non-ostial calcified coronary lesions

BACKGROUND

The safety and efficacy of coronary orbital atherectomy (OA) for treatment of ostial lesions are not yet fully established. We sought to evaluate (OA) treatment of severely calcified ostial and non-ostial lesions.

METHODS

A retrospective analysis of subjects treated with OA for severely calcified ostial and non-ostial lesions, at the Mount Sinai Medical Center, Miami Beach, Florida (MSMCMB) from January 2014 to September 2020, was completed. Study baseline characteristics, lesion and vessel characteristics, procedural outcomes, and in-hospital major adverse cardiovascular events (MACE) were analyzed and compared.

RESULTS

A total of 609 patients that underwent PCI with OA were identified. The majority of patients (81.9 %) had non-ostial lesions, while 16.6 % had ostial lesions (of which 2.8 % classified as aorto-ostial) and 1.5 % had unknown lesion anatomy. The mean age of the overall cohort was 74.0 ± 9.3 years, and 63.5 % were male. All patients received drug-eluting stent (DES) placement, and the overall freedom from MACE was 98.5 %, with no significant difference observed between the ostial and non-ostial groups. The freedom from cardiac death and MI was also similar between the two groups. There were low rates of bleeding complications and severe angiographic complications, and no persistent slow flow/no reflow was reported.

CONCLUSIONS

This study demonstrated no significant differences in in-hospital MACE outcomes between patients with ostial versus non-ostial lesions, indicating that OA is a safe and effective treatment option for both lesion types, including those classified as aorto-ostial.

Acute coronary syndrome demonstrating plaque rupture in calcified plaque visualized by optical coherence tomography and near-infrared spectroscopy combined with intravascular ultrasound

Optical coherence tomography (OCT) can visualize calcification of the coronary plaque as a low-intensity lesion with sharp borders. However, residual lipid tissue inside the calcification could pose a problem in plaque evaluation by OCT. We present a case of acute coronary syndrome (ACS) demonstrating plaque rupture in the calcified plaque. In this case, OCT demonstrated a cavity suspected to represent rupture in the calcified plaque and near-infrared spectroscopy revealed a lipid component behind the calcified plaque. Although calcified plaque is not considered a reason for ACS except for calcified nodules, residual lipid tissue inside the calcification might cause ACS if the thin fibrous cap over the lipid tissue is disrupted, even if surrounded by calcification. <Learning objective: This is the first case report to describe plaque rupture in calcified plaque visualized by OCT and near-infrared spectroscopy. Lipid tissue surrounded by calcification is generally recognized as calcified plaque on OCT because discrimination between lipid tissue and calcification is based on border characteristics. Residual lipid tissue within calcification could pose a problem in plaque evaluation by OCT.>.

Management of calcified coronary artery bifurcation lesions

Calcified coronary artery bifurcation lesions (CBL) remain a challenge for the interventional cardiologist. Evidence regarding treatment of CBL is minimal. Optimal plaque modification is the most important step prior to stent deployment. Provisional stenting is the preferred strategy for most bifurcation lesions. However, two-stent strategy should be considered for BL with compromised large SB (>2.5 mm) supplying a large territory, >70% SB stenosis and lesions more than 5 mm long. In this contemporary review article, we present a simplified approach to treating CBL and demonstrate the approach to specific case examples using our newly developed mobile application, BifurcAID.

Short term outcomes of rotational atherectomy versus orbital atherectomy in patients undergoing complex percutaneous coronary intervention: a systematic review and meta-analysis

OBJECTIVE

Coronary artery calcification (CAC) is one of the paramount hurdles for percutaneous coronary intervention (PCI) since it impedes stent delivery and complete expansion. This study intended to evaluate the short-term clinical and procedural outcomes comparing rotational atherectomy (RA) and orbital atherectomy (OA) in patients with heavily calcified coronary lesions undergoing PCI. Design: This systematic review and meta-analysis included all head-to-head published comparisons of coronary RA versus OA. Procedural endpoints and post-procedural clinical outcomes (30 days/in-hospital), were compared. RevMan 5.3 software was used for data analysis. Results: Seven retrospective observational investigations with a total of 4623 patients, including 3203 patients in the RA group and 1420 patients in the OA group, were incorporated. Compared with OA, the RA group was associated with a higher incidence of myocardial infarction at short-term follow-up (OR: 1.56, 95% CI: 1.07-2.29, p = .02, I² = 0%). No difference was noted among other short-term post-procedural clinical outcomes including all-cause mortality, target vessel revascularization, or major adverse cardiac events. Among procedural complications, RA was associated with reduced coronary artery dissection and arterial perforation. Increased fluoroscopy time was observed in the RA cohort as compared with OA (MD: 4.78, 95% CI: 2.25-7.30, p = .0002, I² = 80%). Conclusion: RA was associated with fewer vascular complications, but at a cost of higher incidence of myocardial infarction and higher fluoroscopy time compared with OA, at short term follow-up. OA is a safe and effective alternative for the management of CAC.

Blooming Artifact Reduction in Coronary Artery Calcification by A New De-blooming Algorithm: Initial Study

The aim of this study was to investigate the use of de-blooming algorithm in coronary CT angiography (CCTA) for optimal evaluation of calcified plaques. Calcified plaques were simulated on a coronary vessel phantom and a cardiac motion phantom. Two convolution kernels, standard (STND) and high-definition standard (HD STND), were used for imaging reconstruction. A dedicated de-blooming algorithm was used for imaging processing. We found a smaller bias towards measurement of stenosis using the de-blooming algorithm (STND: bias 24.6% vs 15.0%, range 10.2% to 39.0% vs 4.0% to 25.9%; HD STND: bias 17.9% vs 11.0%, range 8.9% to 30.6% vs 0.5% to 21.5%). With use of de-blooming algorithm, specificity for diagnosing significant stenosis increased from 45.8% to 75.0% (STND), from 62.5% to 83.3% (HD STND); while positive predictive value (PPV) increased from 69.8% to 83.3% (STND), from 76.9% to 88.2% (HD STND). In the patient group, reduction in calcification volume was 48.1 ± 10.3%, reduction in coronary diameter stenosis over calcified plaque was 52.4 ± 24.2%. Our results suggest that the novel de-blooming algorithm could effectively decrease the blooming artifacts caused by coronary calcified plaques, and consequently improve diagnostic accuracy of CCTA in assessing coronary stenosis.

Comparison of the Efficacy and Safety of Orbital and Rotational Atherectomy in Calcified Narrowings in Patients Who Underwent Percutaneous Coronary Intervention

We aimed to compare the safety and efficacy of rotational atherectomy (RA) and orbital atherectomy (OA) during percutaneous coronary intervention in an all-comer population with severely calcified lesions. We included all patients who underwent percutaneous coronary intervention with OA or RA in our institution from October 2013 until October 2016. Comparison of baseline and procedural characteristics, along with acute complication rates and postprocedural cardiac enzyme elevation, was performed. There were 191 RA and 57 OA patients. Other than creatinine clearance, which was lower in patients with OA (p = 0.01), there were no differences in baseline characteristics. OA was more frequent in left anterior descending artery lesions (p = 0.02), whereas RA was more common in right coronary artery lesions (p = 0.01). Intracoronary imaging rates were above 60% in both groups. There was a higher rate of coronary dissections with OA compared with RA (p = 0.003), but there was no difference in periprocedural events. Maximal troponin levels were similar in both groups. Residual stenosis measured by intravascular ultrasound in 29 patients revealed no significant differences between OA and RA (p = 0.58). In conclusion, RA and OA have similar safety and efficacy profiles in treating patients with calcified coronary lesions, and intracoronary imaging is highly beneficial in identifying coronary injury after atherectomy procedures.

Intravascular ultrasound enhances the safety of rotational atherectomy

Intravascular ultrasound (IVUS) is mainly used in PCI to treat complex lesions, such as left main bifurcation, chronic total occlusion and calcified lesions. Although IVUS yields useful information such as the presence of napkin-ring calcification, the role of IVUS in rotational atherectomy (RA) is not fully appreciated. Recently, since the deliverability and crossability of IVUS catheters have improved, IVUS should be attempted before RA. Even if the IVUS catheter cannot cross the lesion, IVUS provides information just proximal to the target lesion, which would be useful in the selection of the appropriate guidewire and burr size. IVUS can be repeated following RA, which may influence the decision to continue RA with larger burrs. Circumferential calcification is a good indication for RA, since RA can create a calcium crack that facilitates balloon dilatation. However, if the distribution of calcification is not circumferential, the indication for RA can more safely be determined based on IVUS images than angiographic information alone. Because RA burrs usually follow the route taken by the IVUS catheter, the positional relationship between the IVUS imaging core and calcification would be similar to that between the RA burrs and calcification. The relationship between the RA burrs and distribution of calcification is discussed in this review.

Acute Coronary Syndrome Demonstrating Plaque Rupture in Calcified Lesions Visualized by Optical Frequency Domain Imaging

A 68-year-old female with acute coronary syndrome was transferred to our hospital. Emergency coronary angiography showed 90% stenosis with severe calcification in the proximal right coronary artery (RCA). Intravascular ultrasound (IVUS) images were obtained and showed circumferential heavy calcification without any evidence of plaque rupture. Optical frequency domain imaging (OFDI) images were obtained in the RCA lesion 3 days after the initial coronary angiography. A cavity of plaque rupture in the calcified plaque by using OFDI was observed in the lesion, which could not be recognized by IVUS. Necrotic tissue was observed frequently in heavy calcified lesions and was usually hidden behind calcification. Judging from the OFDI images in this case, the thin fibrous cap over the necrotic tissue even if surrounded by calcification was disrupted and might have caused the acute coronary syndrome. However, necrotic tissue surrounded by calcification is generally recognized as calcified plaque in OFDI images because discrimination between necrotic tissue and calcification is based on the border characteristics (low intensity with diffuse border: necrotic tissue, low intensity with sharp border: calcification). Superficial residual necrotic tissue not yet replaced completely by calcification might cause plaque rupture and thus, result in acute coronary syndrome. In fact, there is a variety of OFDI and optical coherence tomography (OCT) characteristics in calcified plaque, such as relatively high intensity without attenuation or very low intensity with attenuation. Residual necrotic tissue within calcification could pose a problem in OCT/OFDI plaque evaluation.

Patient Selection and Procedural Considerations for Coronary Orbital Atherectomy System

Despite advances in technology, percutaneous coronary intervention (PCI) of severely calcified coronary lesions remains challenging. Rotational atherectomy is one of the current therapeutic options to manage calcified lesions, but has a limited role in facilitating the dilation or stenting of lesions that cannot be crossed or expanded with other PCI techniques due to unfavourable clinical outcome in long-term follow-up. However the results of orbital atherectomy presented in the ORBIT I and ORBIT II trials were encouraging. In addition to these encouraging data, necessity for sufficient lesion preparation before implantation of bioresorbable scaffolds lead to resurgence in the use of atherectomy. This article summarises currently available publications on orbital atherectomy (Cardiovascular Systems Inc.) and compares them with rotational atherectomy.

Current understanding of coronary artery calcification

Coronary artery calcification (CAC) is highly prevalent in patients with coronary heart disease (CHD) and is associated with major adverse cardiovascular events. There are two recognized type of CAC—intimal and medial calcification, and each of them have specific risk factors. Several theories about the mechanism of vascular calcification have been put forward, and we currently believe that vascular calcification is an active, regulated process. CAC can usually be found in patients with severe CHD, and this asymptomatic phenomenon make early diagnosis of CAC important. Coronary computed tomographic angiography is the main noninvasive tool to detect calcified lesions. Measurement of coronary artery calcification by scoring is a reasonable metric for cardiovascular risk assessment in asymptomatic adults at intermediate risk. To date, effective medical treatment of CAC has not been identified. Several strategies of percutaneous coronary intervention have been applied to CHD patients with CAC, but with unsatisfactory results. Prognosis of CAC is still a major problem of CHD patients. Thus, more details about the mechanisms of CAC need to be elucidated in order to improve the understanding and treatment of CAC.

Impact of coronary artery calcification in percutaneous coronary intervention with paclitaxel-eluting stents: Two-year clinical outcomes of paclitaxel-eluting stents in patients from the ARRIVE program

OBJECTIVES

The purpose of this study was to evaluate clinical outcomes after percutaneous coronary intervention (PCI) in patients with coronary artery calcification (CAC).

BACKGROUND

Smaller studies have reported worse clinical outcomes in patients with CAC who undergo PCI. The impact of CAC in the drug-eluting stent era is unclear.

METHODS

Data from 7,492 patients treated by PCI with ≥1 TAXUS Express stent in the ARRIVE registry with no inclusion/exclusion criteria were stratified by the severity of CAC, as determined by the operator. Endpoints were independently adjudicated. All major adverse cardiac events were assessed at 2 years.

RESULTS

Moderate/severe CAC was present in 19.6%. The nil/mild CAC group had higher rate of current smokers. The moderate/severe CAC group was older and had a higher prevalence of hypertension, kidney disease, prior coronary artery bypass grafting, congestive heart failure, and left main disease. After adjustment for imbalanced baseline variables, patients with moderate/severe CAC had higher 2 year rates of major adverse cardiac events (18.3% vs 13.5%, p = 0.01) and death (10.3% vs 5.6%, p = 0.02).

CONCLUSIONS

Moderate/severe CAC was associated with increased clinical events in patients who underwent PCI with TAXUS stents. This may be explained in part due to differences important baseline characteristics including more patients with more comorbidities and more complex lesions. After adjustment for imbalanced baseline variables, the moderate/severe CAC group had a higher risk of major adverse cardiac events and death. Improvements in treatment strategies are needed for this high-risk group of patients who undergo PCI. © 2016 Wiley Periodicals, Inc.

Long-term safety and performance of the orbital atherectomy system for treating calcified coronary artery lesions: 5-Year follow-up in the ORBIT I trial

BACKGROUND/PURPOSE

The ORBIT I trial, a first-in-man study, was conducted to evaluate the safety and performance of the orbital atherectomy system (OAS) in treating de novo calcified coronary lesions.

METHODS/MATERIALS

Fifty patients were enrolled between May and July 2008 based on several criteria, and were treated with the OAS followed by stent placement. The safety and performance of the OAS were evaluated by procedural success, device success, and overall major adverse cardiovascular event (MACE) rates, including cardiac death, myocardial infarction (MI) and need for target lesion revascularization (TLR). Our institution enrolled and treated 33 of the 50 patients and continued follow-up for 5 years.

RESULTS

Average age was 54 years and 91% were males. Mean lesion length was 15.9 mm. Device success was 100%, and average number of orbital atherectomy devices (OAD) used per patient was 1.3. Stents were placed directly after OAS in 31/32 patients (96.9%). All stents (average stent per lesion 1.1) were successfully deployed with 0.3% residual stenosis. The overall cumulative MACE rate was 6.1% in-hospital, 9.1% at 30 days, 12.1% at 6 months, 15.2% at 2 years, 18.2% at 3 years and 21.2% at 5 years (4 total cardiac deaths). None of the patients had Q-wave MIs. Angiographic complications were observed in 5 patients. No flow/slow flow due to distal embolization was observed.

CONCLUSIONS

The ORBIT I trial suggests that OAS treatment continues to offer a safe and effective method to change compliance of calcified coronary lesions to facilitate optimal stent placement in these difficult-to-treat patients.

An integrated backscatter ultrasound technique for the detection of coronary and carotid atherosclerotic lesions

The instability of carotid and coronary plaques has been reported to be associated with acute coronary syndrome, strokes and other cerebrovascular events. Therefore, recognition of the tissue characteristics of carotid and coronary plaques is important to understand and prevent coronary and cerebral artery disease. Recently, an ultrasound integrated backscatter (IB) technique has been developed. The ultrasound IB power ratio is a function of the difference in acoustic characteristic impedance between the medium and target tissue, and the acoustic characteristic impedance is determined by the density of tissue multiplied by the speed of sound. This concept allows for tissue characterization of carotid and coronary plaques for risk stratification of patients with coronary and cerebral artery disease. Two- and three-dimensional IB color-coded maps for the evaluation of tissue components consist of four major components: fibrous, dense fibrosis, lipid pool and calcification. Although several ultrasound techniques using special mathematical algorithms have been reported, a growing body of literature has shown the reliability and usefulness of the IB technique for the tissue characterization of carotid and coronary plaques. This review summarizes concepts, experimental procedures, image reliability and the application of the IB technique. Furthermore, the IB technique is compared with other techniques.

Orbital atherectomy system in treating calcified coronary lesions: 3-Year follow-up in first human use study (ORBIT I trial)

BACKGROUND/PURPOSE

The ORBIT I trial evaluated the safety and performance of an orbital atherectomy system (OAS) in treating de novo calcified coronary lesions. Severely calcified coronary arteries pose ongoing treatment challenges. Stent placement in calcified lesions can result in stent under expansion, malapposition and procedural complications. OAS treatment may be recommended to facilitate coronary stent implantation in these difficult lesions.

MATERIALS/METHODS

Fifty patients with de novo calcified coronary lesions were enrolled in the ORBIT I trial. Patients were treated with the OAS followed by stent placement. Our institution treated 33/50 patients and continued follow-up for 3 years.

RESULTS

Average age was 54.4 years and 90.9% were males. Mean lesion length was 15.9mm. The average number of OAS devices used per patient was 1.3. Procedural success was achieved in 97% of patients. Angiographic complications were observed in five patients (two minor dissections, one major dissection and two perforations). The cumulative major adverse cardiac event (MACE) rate was 6.1% in-hospital, 9.1% at 30 days, 12.1% at 6 months, 15.2% at 2 years, and 18.2% at 3years. The MACE rate included two in-hospital non Q-wave myocardial infarctions (MI), one additional non Q-wave MI at 30 days leading to target lesion revascularization (TLR), and three cardiac deaths.

CONCLUSIONS

The ORBIT I trial suggests that OAS treatment may offer an effective method to modify calcified coronary lesion compliance to facilitate optimal stent placement in these difficult-to-treat patients with acceptable levels of safety up to 3 years post-index procedure.

Plaque characteristics of thin-cap fibroatheroma evaluated by OCT and IVUS

OBJECTIVES

The purpose of this study was to assess plaque characteristics of optical coherence tomography (OCT)-derived thin-cap fibroatheroma (TCFA) by integrated backscatter intravascular ultrasound (IB-IVUS).

BACKGROUND

Radiofrequency signal-derived IVUS tissue characterization technology has become clinically available and provided objective and quantitative plaque characteristics of the coronary vessel wall. Integrated backscatter IVUS is one of the tissue characterization methods that can possibly provide quantitative plaque characteristics of the OCT-derived TCFA.

METHODS

Eighty-one coronary lesions with plaque burden >40% were selected and analyzed with both IB-IVUS and OCT. The OCT-derived TCFA was defined as a presence of thin fibrous cap (<65 μm) overlying a signal-poor lesion with diffuse border representing a lipid-rich plaque. By conventional gray-scale IVUS, external elastic membrane (EEM) cross-sectional area (CSA), lumen CSA, plaque plus media (P+M) CSA, plaque burden and remodeling index were measured. By IB-IVUS, plaque characteristics were further classified as fibrosis, dense fibrosis, calcification, or lipid pool.

RESULTS

Optical coherence tomography identified 40 TCFAs (49%) and 41 non-TCFAs. The EEM CSA, P+M CSA, plaque burden, and remodeling index were significantly larger in OCT-derived TCFA than non-TCFA. By IB-IVUS, percentage lipid pool area (= lipid pool area/P+M CSA × 100) was significantly higher (62.4 ± 12.8% vs. 38.4 ± 13.1%, p<0.0001) and percentage fibrosis area (= fibrosis area/P+M CSA × 100) was significantly lower (34.6 ± 11.4% vs. 50.5 ± 8.7%, p<0.0001) in OCT-derived TCFA than non-TCFA. By receiver-operator characteristic curve analysis, percentage lipid pool area ≥55%, percentage fibrosis area ≤41%, and remodeling index ≥1.0 were predictors of OCT-derived TCFA.

CONCLUSIONS

The OCT-derived TCFA had larger plaque burden and positive remodeling with predominant lipid component and less fibrous plaque assessed by IB-IVUS.

Comparison of optical coherence tomography and intravascular ultrasound for the assessment of in-stent tissue coverage after stent implantation

AIMS

At present there exists no direct comparative data for the detection of in-stent tissue coverage as assessed by intravascular ultrasound (IVUS) and optical coherence tomography (OCT) in clinical settings. To explore this subject, we investigated the correlation between the IVUS and OCT measurements derived from a contemporary population.

METHODS AND RESULTS

The present study includes 20 patients who had stents imaged at a six months follow-up with both IVUS and OCT, acquired with an automated pull-back. Off-line analyses were done by an independent validated Core-Lab (RHR, Rome, Italy). Measurements of stent length obtained by IVUS and OCT were 16.3+/-3.0 mm and 16.2+/-3.8 mm respectively (p=0.82) and were similar to nominal length (16.3+/-3.3 mm). Luminal area in the OCT image set was lower than that obtained in the corresponding IVUS image set (3.83+/-1.60 mm2 vs 4.05+/-1.44 mm2, p<0.001), while stent area was significantly higher when measured by OCT (6.61+/-1.39 mm2 vs 6.17+/-1.07 mm2, p<0.001). The percentage of tissue coverage measured by IVUS was lower than that measured in the corresponding OCT image sets (35.5+/-16.4% vs 43.4+/-16.1%, p<0.001). Correlation coefficients were high for repeated OCT measurements by two different observers (r=0.99).

CONCLUSIONS

OCT can quantify in-stent coverage and detect strut healing with high reproducibility. IVUS tends to underestimate the percentage of in-stent tissue coverage as compared to OCT.

Soluble elastin decreases in the progress of atheroma formation in human aorta

BACKGROUND

The serum levels of soluble elastin increase in patients with aortic dissection, but its distribution and characteristics are unclear.

METHODS AND RESULTS

The 173 aortic specimens were categorized into 4 groups under microscopy (non-atherosclerotic aorta, n=13; fiber-rich plaque, n=77; lipid-rich plaque, n=66; ruptured plaque, n=17). Soluble elastin was abundant within the intima of both the non-atherosclerotic aorta and fiber-rich plaque, rather than in the media, and was decreased within the intima of lipid-rich and ruptured plaques. Soluble elastin levels decreased with progress of atherosclerosis (6.0 +/-0.3 microg/mg protein in non-atherosclerotic aorta; 5.8 +/-0.2 microg/mg protein in fiber-rich plaque; 4.9 +/-0.2 microg/mg protein in lipid-rich plaque; 2.8 +/-0.4 microg/mg protein in ruptured plaque, P<0.05). As well, both matrix metalloprotease-9 activity and elastin mRNA expression showed inverse distribution against soluble elastin (r=0.437, P<0.0001; r=0.186, P<0.05, respectively). Multivariable analysis revealed a decrease in the level of soluble elastin in ruptured plaque (2.8 +/-0.4 microg/mg protein in ruptured plaque, n=18; 5.5 +/-0.2 microg/mg protein in non-ruptured plaque, n=155, P<0.01). Furthermore, western blot showed soluble elastin consists of heterogeneous molecular pattern proteins.

CONCLUSIONS

Both the synthesis and degradation of elastin may be enhanced in active atherosclerotic lesions.

Tissue characterization of coronary plaques: comparison of integrated backscatter intravascular ultrasound with virtual histology intravascular ultrasound

BACKGROUND

Integrated backscatter (IB) intravascular ultrasound (IVUS) and IVUS Virtual Histology (VH) have been developed for tissue characterization, but have never been compared directly. The purpose of this study was to compare the overall agreement between IB-IVUS and IVUS-VH in the tissue characterization of plaques from the same coronary arterial cross-section.

METHODS AND RESULTS

Images were acquired from 46 coronary arteries from 25 cadavers. Of a total of 392 histology/IVUS image pairs, 152 pairs were diagnosed as Stary's type III, IV, Va, Vb and Vc, and compared for IB-IVUS, IVUS-VH and histology. In the qualitative comparison, the overall agreement between histological and IB-IVUS diagnoses was higher (kappa = 0.81, 95% confidence interval (CI): 0.74-0.89) than that of the IVUS-VH diagnoses (kappa = 0.66, 95%CI: 0.56-0.75). The % fibrosis area determined by IB-IVUS was significantly correlated with the relative area of fibrosis based on histology (r = 0.67, p < 0.001). In the quantitative comparison, the overall agreement between the histological and IB-IVUS diagnoses was higher (kappa = 0.83, 95% CI: 0.75-0.91) than that of the IVUS-VH diagnoses (kappa = 0.73, 95% CI: 0.63-0.83).

CONCLUSION

Based on histology as the gold standard, IB-IVUS provided higher diagnostic accuracy than IVUS-VH for tissue characterization of coronary plaques.

The role of inflammation in coronary artery calcification

Vascular calcification is an age-dependent, common finding in human coronary arteries and begins as early as the second decade of life, just after fatty streak formation. Previous studies have showed that the severity of coronary calcification is closely related to atherosclerotic plaque burden and cardiac event rate. In the past few decades, coronary calcification has been considered passive and degenerative. With recent clinical and basic research, however, there is increasing recognition that coronary calcification is an active, regulated process. Current diagnostic methods for coronary artery calcification (CAC) are usually traditional coronary angiography, intravascular ultrasound (IVUS), electron beam computed tomography (EBCT) and multi-slice computed tomography (MSCT) while treatment for patients with calcified coronary arteries is troublesome. Several lines of evidence suggest that inflammation plays a major role in the development of atherosclerosis as well as its clinical manifestations. Recent study showed that inflammatory process might be also involved in coronary calcification. Accordingly, measurements of inflammatory markers such as C-reactive protein (CRP) may in part reflect indices of atherosclerosis, such as coronary calcification, and are likely to provide distinct information regarding cardiovascular risk. In this article, we review the current evidence of relationship between coronary calcification and inflammation for purpose of drawing the more attention on the inflammatory mechanism of coronary calcification, which may change our research as well as therapeutic strategies for coronary calcification in the future.