Prognosis of vulnerable plaque on computed tomographic coronary angiography with normal myocardial perfusion image

AIMS

Increasing clinical evidence has emphasized the importance of coronary plaque characteristics, rather than the severity of luminal narrowing on acute coronary syndrome (ACS) outcome. Computed tomographic coronary angiography (CTCA) is a unique, non-invasive approach for assessing plaque characteristics. This study was prospectively designed to investigate the prognostic value of physiologically non-obstructive but a vulnerable coronary plaque on CTCA for predicting future ACS events.

METHODS AND RESULTS

This study consisted of 543 patients who had undergone CTCA and had normal findings on exercise-stress myocardial perfusion single-photon emission computed tomography. CTCA analysis included the presence of >50% luminal stenosis and vulnerable features including positive remodelling (PR), low-attenuation plaque, and ring-like sign. The primary endpoint was ACS events including cardiac death, non-fatal myocardial infarction, and unstable angina. The mean follow-up period was 3.4 ± 0.8 years. The 3-year cumulative event rate was 1.2% per year, and 87% of ACS events occurred in plaques with at least one of vulnerable features. In patient-based multivariate analysis, the presence of plaque with vulnerable features on CTCA was a significant predictor for future ACS events (P = 0.001). Patients with vulnerable plaque had worse ACS outcomes compared with those without vulnerable plaques (3-year cumulative event rate; 3.2 per year vs. 0.8%, P < 0.001).

CONCLUSION

This study demonstrated that physiologically non-obstructive but vulnerable coronary plaques were associated with future ACS events. We should pay more attention to currently non-obstructive plaque but showing vulnerable morphologies on CTCA.

Prognostic value of coronary flow reserve on long-term cardiovascular outcomes in patients with chronic kidney disease

Cardiovascular (CV) diseases and chronic kidney disease (CKD) have common predisposing factors that subsequently cause microvascular dysfunction. In the absence of obstructive coronary artery disease, coronary flow reserve (CFR) represents the status of coronary microcirculation. This study aimed to investigate the prognostic importance of impaired CFR, as a marker of microvascular dysfunction, on long-term CV outcomes in patients with CKD. This study consisted of 139 patients with an estimated glomerular filtration rate of <60 ml/min/1.73 m(2) who had no obstructive narrowing of the left anterior descending artery. Transthoracic Doppler echocardiography was used to measure CFR in the left anterior descending artery. During the follow-up period (3.3 ± 1.6 years), CV events occurred in 26 patients (18.7%). Multivariate analysis that included CFR as a continuous value identified a serum level of C-reactive protein (hazard ratio 1.41, p = 0.03) and a value of CFR (hazard ratio 0.21, p = 0.009) as determinants for CV events, independent of traditional CV risk factors. Patients with a CFR of <2.0 had worse CV outcomes compared with those with a CFR of ≥2.0 (p <0.001). In conclusion, transthoracic Doppler echocardiographically derived CFR was useful for the risk stratification of CV outcomes in patients with CKD. The presence of microvascular dysfunction may play an important role in the association between CKD and future CV events.

Insulin resistance is associated with coronary plaque vulnerability: insight from optical coherence tomography analysis

AIMS

Previous studies have reported that insulin resistance plays an important role in the progression of atherosclerosis. However, the relationship between insulin resistance and coronary plaque instability is not well established. The purpose of this study was to assess the relationship between insulin resistance and coronary plaque characteristics identified by optical coherence tomography (OCT).

METHODS AND RESULTS

This study enrolled 155 consecutive patients undergoing percutaneous coronary intervention. OCT image acquisitions were performed in the culprit lesions. Insulin resistance was identified using the homeostasis model assessment of insulin resistance (HOMA-IR). Subjects were divided into three tertiles according to the HOMA-IR values. Patients in the higher HOMA tertile had more frequent prevalence of lipid-rich plaques than those in the middle and lower tertiles (83 vs. 62 vs. 57%; P = 0.01). The thin-cap fibroatheroma (TCFA) prevalence rates among the higher (>2.5), middle (1.4-2.5), and lower HOMA-IR (<1.4) tertiles were 50, 29, and 26% (P = 0.02). The microvessel prevalence rates of the three tertiles were 54, 39, and 28% (P = 0.02). Furthermore, in the higher HOMA-IR group, the fibrous cap was significantly thinner compared with the other two tertiles (vs. lower HOMA-IR, P = 0.009; vs. middle HOMA-IR, P = 0.008). On multivariate analysis, acute coronary syndrome [odds ratio (OR): 17.98; 95% confidence interval (CI): 7.12-52.02; P < 0.0001] and HOMA-IR >2.50 (OR: 3.57; 95% CI: 1.42-9.55; P = 0.007) were independent predictors for the presence of TCFA.

CONCLUSION

This study suggests that insulin resistance might be associated with coronary plaque vulnerability.

Tolvaptan attenuates left ventricular fibrosis after acute myocardial infarction in rats

Tolvaptan, a non-peptide V2-receptor antagonist, is a newly developed diuretic agent. Recently, we reported that tolvaptan has diuretic as well as anti-inflammatory and anti-fibrotic actions in chronic heart failure. In this study, we investigated whether tolvaptan has a cardioprotective effect in acute heart failure after myocardial infarction (MI). After MI induction, rats were randomized into 6 groups as follows: vehicle group, group treated with 15 mg∙kg⁻¹∙day⁻¹ furosemide, 2 groups treated with 3 or 10 mg∙kg⁻¹∙day⁻¹ tolvaptan, and 2 groups treated with 15 mg∙kg⁻¹∙day⁻¹ furosemide combined with 3 or 10 mg∙kg⁻¹∙day⁻¹ tolvaptan. Each agent was administered for 2 weeks, and blood pressure levels and infarct sizes were similar in all MI groups. Lower left ventricular end-systolic volumes and greater improvement of left ventricular ejection fraction were observed in the tolvaptan-treated groups compared with the vehicle group. In contrast, furosemide alone did not improve them. Sirius red staining revealed that tolvaptan significantly repressed MI-induced interstitial fibrosis in the left ventricle. MI-induced mRNA expressions related to cardiac load, inflammation, and fibrosis were significantly attenuated in the combination group. The combination treatment also repressed MI-induced mineralocorticoid receptor expression. Tolvaptan, or combination of furosemide and tolvaptan, may improve cardiac function in acute MI.

A case of a lesion containing an intracoronary thrombus detected as hyperintense plaque on T1-weighted cardiovascular magnetic resonance in a patient with silent myocardial ischemia

Many investigators have speculated that hyperintense plaques (HIPs) of the carotid artery on noncontrast T1-weighted imaging (T1WI) in cardiovascular magnetic resonance indicate the presence of mural or intraplaque hemorrhage containing methemoglobin. However, coronary plaque imaging with T1WI is challenging, and the clinical significance of coronary HIPs on T1WI remains unknown. Incidentally, it is very rare to find an intracoronary thrombus at the culprit lesion site in patients in stable condition. This article reports the case of a lesion containing an intracoronary thrombus, detected as HIP on T1WI associated with the filter no-reflow phenomenon in a patient with silent myocardial ischemia.

Very rapid effect of pitavastatin on microvascular function in comparison to rosuvastatin: reactive hyperemia peripheral arterial tonometric study

BACKGROUND

It has been reported that pitavastatin improves endothelial function faster than other statins. Recently introduced reactive hyperemia peripheral arterial tonometry (RH-PAT) provides objective and quantitative assessment of peripheral microvascular function.

PURPOSE

This study aimed to investigate whether peripheral microvascular function improved 2 hours after pitavastatin in subjects with coronary artery disease (CAD) using RH-PAT, and the results were compared with those of rosuvastatin.

METHODS

This study included 94 subjects with CAD, assigned to a group given 2 mg of pitavastatin (n = 36), a group given 2.5 mg of rosuvastatin (n = 38), and a control group (n = 20). RH-PAT examinations were performed before and 2 hours after statin administration.

RESULTS

The RH-PAT index increased 2 hours after pitavastatin administration from 1.82 ± 0.45 to 2.16 ± 0.62 (P = 0.02), whereas there were no differences in the RH-PAT index in the rosuvastatin group (1.79 ± 0.71 to 1.91 ± 0.53, P = 0.09) and the control group (1.68 ± 0.36 to 1.84 ± 0.58, P = 0.4). No significant changes were observed at 2 hours in serum cholesterol levels in each group.

CONCLUSION

The present study demonstrated that peripheral microvascular function improved 2 hours after a single clinical dose of pitavastatin, but not after rosuvastatin.

Changes in serum cholesterol levels determine future risk of cardiovascular events in patients with acute coronary syndrome in the Japanese Coronary Artery Disease (JCAD) Study

BACKGROUND

Although increased attention is given to assess absolute values of serum cholesterol profiles as optimal markers for preventing future cardiovascular (CV) events, changes in cholesterol profiles also have the potential to be associated with CV disease outcome in Japanese patients with acute coronary syndrome (ACS).

METHODS

From the database of the Japanese Coronary Artery Disease (JCAD) study, 2664 patients with ACS who had serial measurements of serum cholesterol profile parameters were enrolled. These patients were followed-up for a mean period of 2.7 years. The endpoint was all CV events. Baseline clinical characteristics of patients with and without CV events were adjusted by the propensity score matching analysis.

RESULTS

None of the serum absolute cholesterol profiles at baseline and 6 months later was associated with CV events, except for baseline serum total cholesterol level. However, large improvements in cholesterol profiles correlated with better CV disease outcome.

CONCLUSIONS

This subanalysis of JCAD demonstrated the importance of serial assessment of serum cholesterol profiles for secondary prevention of CV events in Japanese patients with ACS. Changes in serum cholesterol profiles, rather than their absolute values, correlated with future CV events.

Napkin-ring sign on coronary CT angiography for the prediction of acute coronary syndrome

OBJECTIVES

The aim of this study was to determine the predictive value of the napkin-ring sign on coronary computed tomography angiography (CTA) for future acute coronary syndrome (ACS) events in patients with coronary artery disease.

BACKGROUND

Recent studies have reported a close association between the napkin-ring sign on coronary CTA and thin-cap fibroatheroma.

METHODS

The subjects of this prospective study were 895 consecutive patients who underwent coronary CTA examination and were followed for >1 year. The primary endpoint was an ACS event (cardiac death, nonfatal myocardial infarction, or unstable angina pectoris). The coronary CTA analysis included the presence of obstructive plaque, positive remodeling (PR), low-attenuation plaque (LAP), and the napkin-ring sign. The napkin-ring sign was defined by the following criteria: 1) the presence of a ring of high attenuation around certain coronary artery plaques; and 2) attenuation of the ring presenting higher than those of the adjacent plaque and no >130 Hounsfield units.

RESULTS

Of the 12,727 segments, 1,174 plaques were observed, including plaques with PR in 130 segments (1.0%), LAP in 107 segments (0.8%), and napkin-ring signs in 45 segments (0.4%). Thirty-six of the 45 plaques with napkin-ring signs (80%) overlapped with those showing either PR or LAP. During the follow-up period (2.3 ± 0.8 years), 24 patients (2.6%) experienced ACS events, and plaques developed in 41% with a napkin-ring sign. Segment-based Cox proportional hazards models analysis showed that PR (p < 0.001), LAP (p = 0.007), and the napkin-ring sign (p < 0.0001) were independent predictive factors for future ACS events. Kaplan-Meier analysis demonstrated that plaques with napkin-ring signs showed a higher risk of ACS events compared with those without a napkin-ring sign.

CONCLUSIONS

The present study demonstrated for the first time that the napkin-ring sign demonstrated on coronary CTA was strongly associated with future ACS events, independent of other high-risk coronary CTA features. Detection of the napkin-ring sign could help identify coronary artery disease patients at high risk of future ACS events.

Left hepatic trisectionectomy for advanced perihilar cholangiocarcinoma

BACKGROUND

Data on outcomes of left hepatic trisectionectomy (LT) for perihilar cholangiocarcinoma are limited. The aim of this study was to clarify short- and long-term outcomes of LT for perihilar cholangiocarcinoma.

METHODS

Patients with perihilar cholangiocarcinoma who underwent LT between January 2000 and October 2011 were analysed. Surgical variables, mortality, morbidity (Clavien grade I-V), recurrence sites and survival were compared between subjects who underwent LT, right hemihepatectomy or left hemihepatectomy.

RESULTS

A total 214 patients underwent resection for perihilar cholangiocarcinoma, 25 (11·7 per cent) of whom underwent LT, 88 (41·1 per cent) right hemihepatectomy and 94 (43·9 per cent) left hepatectomy. There were no deaths among those who had LT, but 20 patients developed complications. The incidence of grade IIIa complications was significantly higher among patients who underwent LT than in patients who had right or left hemihepatectomy (P = 0·001 and P < 0·001 respectively). Only one patient developed a grade IIIb or IV complication (liver failure) after LT. The overall 5-year survival rate after LT was 39 per cent and median survival was 45 months. There were no significant differences in survival between patients who underwent LT and those who had a right or left hemihepatectomy.

CONCLUSION

LT may provide a good outcome for advanced perihilar cholangiocarcinoma.

Deiodinase 2 upregulation demonstrated in osteoarthritis patients cartilage causes cartilage destruction in tissue-specific transgenic rats

OBJECTIVE

Chondrocyte hypertrophy followed by cartilage destruction is a crucial step for osteoarthritis (OA) development, however, the underlying mechanism remains largely unknown. The objectives of this study are to identify the gene that may cause cartilage hypertrophy and to elucidate its role on OA pathogenesis.

DESIGN

Gene expression profiles of cartilages from OA patients and normal subjects were examined by microarray analysis. Expression of deiodinases, enzymes for regulation of triiodothyronine (T3) biosynthesis, in human and rat articular cartilage (AC) were examined by real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Rat ACs and chondrocytes were treated with T3 to investigate its role on chondrocyte hypertrophy and inflammatory reaction. Cartilage-specific Type II deiodinase (DIO2) transgenic rats were generated using bacterial artificial chromosome harboring the entire rat Col2a1 and human DIO2 gene. An experimental OA model was created in the animal to examine the role of DIO2 on cartilage degeneration.

RESULTS

DIO2 is highly expressed in OA patient AC compared to normal control. In rat AC, DIO2 is specifically expressed among deiodinases and dominantly expressed the same as in brown adipose tissue. T3 induces hypertrophic markers in articular chondrocyte and cartilage explant culture, and enhances the effect of IL-1α on induction of cartilage degrading enzymes. Importantly, cartilage-specific DIO2 transgenic rats are more susceptible to knee joint destabilization and develop severe AC destruction.

CONCLUSION

Our findings demonstrate that upregulated expression of DIO2 in OA patient cartilage might be responsible for OA pathogenesis by enhancing the chondrocyte hypertrophy and inflammatory response.