Integrated backscatter and intima-media thickness of the thoracic aorta evaluated by transesophageal echocardiography in hypercholesterolemic patients: effect of pitavastatin therapy

Aortic Sources of Embolism

Aortic arch atheroma is a frequent finding in ischemic stroke patients. Its role as a source of cerebral emboli or a marker of atherosclerosis is unclear. Transesophageal echography is considered the gold standard for its detection, whereas computed tomography angiography is a good alternative; magnetic resonance and positron emission tomography could be proposed to better analyze plaque vulnerability. Despite the interest in this condition, the optimal antithrombotic treatment remains uncertain, while intensive lipid-lowering therapy should be recommended. This review aims to offer guidance on patients with aortic arch atheroma, about its causal role in stroke, diagnosis, and treatment based on current available evidence.

Aortic versus carotid intima-media thickness and impact of aortic valve disease

BACKGROUND AND AIMS

Intima-media thickness is a marker for atherosclerosis but is also influenced by shear stress and flow. We evaluated the relation between intima-media thickness of the descending aorta (AoIMT) and the common carotid artery (CIMT) in patients with and without severe aortic valve disease (sAVD).

METHODS

A total of 310 patients (233 with sAVD, 77 without) were examined with regard to AoIMT and CIMT using transesophageal echocardiography and carotid ultrasound, respectively, before valvular and/or aortic surgery. Digitally stored B-mode images were used for semiautomatic AoIMT and CIMT measurements.

RESULTS

There were no significant differences in patients with or without sAVD with regard to AoIMT (1·35 ± 0·31 vs. 1·35 ± 0·33 mm) or CIMT (0·80 ± 0·15 vs. 0·78 ± 0·16 mm). The correlations between AoIMT and CIMT were r = 0·29 in patients with and r = 0·51 in patients without sAVD, and the difference between these correlations was significant (P<0·05). In multivariate regression, age was the main determinant for AoIMT and CIMT in both groups, further in sAVD, the aortic mean pressure gradient (P_mean ) was a determinant of AoIMT, but not of CIMT.

CONCLUSIONS

The correlation between CIMT and AoIMT is weaker in patients with sAVD compared to those without sAVD. P_mean is also a significant predictor of AoIMT, but not of CIMT. This implies that, in addition to the atherosclerotic process, turbulent aortic flow or altered blood flow helicity created by large stroke volumes and diastolic flow reversal or high-velocity jets, affect the intima-media of the descending aorta and common carotid artery differently.

Anti-inflammatory and morphologic effects of pitavastatin on carotid arteries and thoracic aorta evaluated by integrated backscatter trans-esophageal ultrasound and PET/CT: a prospective randomized comparative study with pravastatin (EPICENTRE study)

Background

We sought to evaluate the effects of a strong lipophilic statin (pitavastatin) on plaque components and morphology assessed by transesophageal echocardiography (TEE) and transthoracic echocardiography (TTE), as well as plaque inflammation assessed by 18 F-fluorodeoxyglucose (FDG) PET/CT in the thoracic aorta and the carotid artery. Furthermore, we compared the effects of pitavastatin with those of mild hydrophilic statin (pravastatin).

Methods

We examined atherosclerotic plaques in the thoracic aorta by TEE and those in the carotid artery by integrated backscatter (IBS)-TTE and PET/CT. We identified the target plaque, where there was macrophage infiltration and inflammation, by strong FDG uptake in the thoracic aorta and carotid arteries and measured maximum standard uptake values (max SUV) by PET/CT. We measured the intima-media thickness (IMT) and the corrected IBS (cIBS) values in the intima-media complex by TEE and TTE at the same site of FDG accumulation by PET/CT.

Results

Patients were randomly divided into two treatment groups: a pitavastatin group (PI group: n =10, 68.4 ± 5.1 years) and a pravastatin group (PR group: n =10, 63.9 ± 11.2 years). The same examinations were performed after six months at the same site in each patient. We used calculated target-to-background ratio (TBR) to measure max SUV of plaques and evaluated percent change of TBR. There was no significant difference in low density lipoprotein-cholesterol, TBR, IMT and cIBS values in plaques at baseline between the PI and PR groups. After treatment, there was greater improvement in TBR, cIBS values and IMT in the PI group than the PR group.

Conclusions

The pravastatin treatment was less effective on plaque inflammation than pitavastatin treatment. This trend was the same in the carotid arteries and the thoracic aorta. Pitavastatin not only improved the atherosis as measured by IMT and cIBS values but also attenuated inflammation of plaques as measured by max SUV at the same site. The present study indicated that pitavastatin has stronger effects on the regression and stabilization of plaques in the thoracic aorta and carotid arteries compared with pravastatin.

Motion of left atrial appendage as a determinant of thrombus formation in patients with a low CHADS2 score receiving warfarin for persistent nonvalvular atrial fibrillation

BACKGROUND

The aim of this study was to define the independent determinants of left atrial appendage (LAA) thrombus among various echocardiographic parameters measured by Velocity Vector Imaging (VVI) in patients with nonvalvular atrial fibrillation (AF) receiving warfarin, particularly in patients with a low CHADS2 score.

METHODS

LAA emptying fraction (EF) and LAA peak longitudinal strain were measured by VVI using transesophageal echocardiography in 260 consecutive patients with nonvalvular persistent AF receiving warfarin. The patients were divided into two groups according to the presence (n=43) or absence (n=217) of LAA thrombus. Moreover, the patients within each group were further divided into subgroups according to a CHADS2 score ≤1.

RESULTS

Multivariate logistic regression analysis showed that LAAEF was an independent determinant of LAA thrombus in the subgroup of 140 with a low CHADS2 score. Receiver operating characteristics curve analysis showed that an LAAEF of 21% was the optimal cutoff value for predicting LAA thrombus.

CONCLUSIONS

LAA thrombus formation depended on LAA contractility. AF patients with reduced LAA contractile fraction (LAAEF ≤21%) require strong anticoagulant therapy to avoid thromboembolic events regardless of a low CHADS2 score (≤1).

Left atrial pathological degeneration assessed by integrated backscatter transesophageal echocardiography as a predictor of progression to persistent atrial fibrillation: results from a prospective study of three-years follow-up

Background

It is recognized that one of the causes of atrial fibrillation (AF) is pathological degeneration of the left atrium (LA). However, prospective study that elucidated the relationship between the incidence of persistent AF and pathological degeneration has not been performed. The purpose of this study was to elucidate the usefulness of integrated backscatter (IBS) values for the prediction of progression from paroxysmal AF (PAF) to persistent AF.

Methods

We measured IBS values of the entire LA wall at 5 mm intervals (except the posterior wall) in 27 patients with paroxysmal AF and evaluated progression to persistent AF for three years. IBS values were acquired with transesophageal echocardiography (TEE) using a 4–7 MHz transducer. IBS values were calculated as the average power of the backscattered signal from regions of interest (ROI). Each IBS value was color-coded to construct three dimensional maps.

Results

Average IBS values of total voxels in color-coded maps in the persistent AF group were significantly greater than those in the non-persistent AF group (25.8 ± 5.0 dB vs. 17.4 ± 10.2 dB, p = 0.047), whereas there was no significant difference in LA diameter between the persistent AF and the non-persistent AF group. There was significant difference in persistent AF-free survival after the baseline measurements in the subjects stratified by IBS value (<20 dB versus ≥20 dB) (univariate Cox regression analysis: hazard ratio: 8.74, p =0.046).

Conclusion

Using IBS values measured by TEE, we can identify an increase in atrial degeneration that may predict the occurrence of persistent AF before LA dilation.

Are all statins the same? Focus on the efficacy and tolerability of pitavastatin

Pitavastatin is the newest member of the HMG-CoA reductase inhibitor family and is approved as adjunctive therapy to diet to reduce elevated levels of total cholesterol, low-density lipoprotein (LDL) cholesterol, apolipoprotein (Apo) B, and triglycerides and to increase levels of high-density lipoprotein (HDL) cholesterol in adult patients with primary hyperlipidemia or mixed dyslipidemia. Pitavastatin undergoes minimal metabolism by cytochrome P450 (CYP) enzymes and, therefore, has a low propensity for drug-drug interactions with drugs metabolized by CYP enzymes or the CYP3A4 substrate grapefruit juice. In clinical trials, pitavastatin potently and consistently reduced serum levels of total, LDL, and non-HDL cholesterol, and triglycerides in patients with primary hypercholesterolemia where diet and other non-pharmacological measures were inadequate. Mean reductions from baseline in serum total and LDL cholesterol and triglyceride levels were 21-32%, 30-45%, and 10-30%, respectively. Moreover, a consistent trend towards increased HDL cholesterol levels of 3-10% was seen. Long-term extension studies show that the beneficial effects of pitavastatin are maintained for up to 2 years. Pitavastatin produces reductions from baseline in serum total and LDL cholesterol levels to a similar extent to those seen with the potent agent atorvastatin and to a greater extent than those seen with simvastatin or pravastatin. In the majority of other studies comparing pitavastatin and atorvastatin, no significant differences in the favorable effects on lipid parameters were seen, although pitavastatin was consistently associated with trends towards increased HDL cholesterol levels. Pitavastatin also produces beneficial effects on lipids in patients with type 2 diabetes mellitus and metabolic syndrome without deleterious effects on markers of glucose metabolism, such as fasting blood glucose levels or proportion of glycosylated hemoglobin. Pitavastatin appears to exert a number of beneficial effects on patients at risk of cardiovascular events independent of lipid lowering. In the JAPAN-ACS (Japan Assessment of Pitavastatin and Atorvastatin in Acute Coronary Syndrome) study, pitavastatin was non-inferior to atorvastatin at reducing plaque volume in patients with ACS undergoing percutaneous coronary intervention. Further beneficial effects, including favorable effects on the size and composition of atherosclerotic plaques, improvements in cardiovascular function, and improvements in markers of inflammation, oxidative stress, and renal function, have been demonstrated in a number of small studies. Pitavastatin is generally well tolerated in hyperlipidemic patients with or without type 2 diabetes, with the most common treatment-related adverse events being musculoskeletal or gastrointestinal in nature. Increases in plasma creatine kinase levels were seen in <5% of pitavastatin recipients and the incidence of myopathy or rhabdomyolysis was extremely low. In summary, pitavastatin, the latest addition to the statin family, produces potent and consistent beneficial effects on lipids, is well tolerated, and has a favorable pharmacokinetic profile. The combination of a potent decrease in total and LDL cholesterol levels and increase in HDL cholesterol levels suggest that pitavastatin may produce substantial cardiovascular protection.

Pitavastatin approved for treatment of primary hypercholesterolemia and combined dyslipidemia

Pitavastatin was first developed in Japan and is expanding the regions in which it is clinically available. A considerable number of clinical studies have been conducted and published to date on the usefulness of pitavastatin for patients with primary hypercholesterolemia or combined dyslipidemia. Pitavastatin demonstrates potent low-density lipoprotein cholesterol reduction at low doses of 1–4 mg/day. It also affects the regression of coronary plaques, as observed in intravascular ultrasound-guided percutaneous coronary intervention studies. Moreover, the persistent, long-term high-density lipoprotein cholesterol elevation observed in the populations treated with pitavastatin is worthy of further attention. The reported improvements in lipid profiles are consistent among the studies conducted in Japan, Korea, Thailand, and Europe. In light of accumulating clinical experience worldwide, pitavastatin is now expected to establish its position for preventing and treating cardiovascular disease.

Premature aortic atherosclerosis in systemic lupus erythematosus: a controlled transesophageal echocardiographic study

OBJECTIVE

Premature carotid and coronary atherosclerosis are common in systemic lupus erythematosus (SLE), but data on aortic atherosclerosis (AA) are limited. Thus, using multiplane transesophageal echocardiography (TEE), we sought to determine the prevalence and clinical correlates of AA in patients with SLE.

METHODS

Forty-seven patients with SLE (44 women, age 38 +/- 12 years) and 21 healthy controls (19 women, age 34 +/- 12 years) underwent clinical and laboratory evaluations and TEE to assess AA defined as aortic intima media thickness (IMT) > 0.86 mm or plaques as > 50% focal IMT as compared with surrounding walls. TEE studies were interpreted by an experienced observer unaware of subjects' clinical data.

RESULTS

The prevalence of abnormal aortic IMT, plaques, or both lesions was higher in patients as compared to controls (37%, 23%, and 43% vs 14%, 0%, and 14%, respectively, all p </= 0.02). In patients, age at diagnosis of SLE was the only positive independent predictor of AA [OR 1.12 per year from diagnosis of SLE, 95% confidence interval (CI) 1.04-1.19, p = 0.001] and cyclophosphamide therapy was the only negative independent predictor of AA (OR 0.186, 95% CI 0.153-0.95, p = 0.04, equivalent to 5.4 times less likely to develop AA).

CONCLUSION

AA is common in young patients with SLE and is predicted by a later age at diagnosis of SLE, but is negatively correlated with cyclophosphamide therapy. Thus, early diagnosis and more aggressive immunosuppressive therapy may be required to decrease the development and progression of atherosclerosis in patients with SLE.