Effect of skin antiseptic solutions on the incidence of catheter-related bloodstream infection: a systematic review and network meta-analysis

BACKGROUND

The most effective skin antiseptic solution to reduce the incidence of catheter-related bloodstream infections (CRBSI) remains unknown.

AIM

To compare solutions with different chlorhexidine (CHG)-based concentrations and povidone-iodine (PVI) in adults with a central venous catheter (CVC) or arterial catheter, and identify an association with the incidence of CRBSI.

METHODS

This study evaluated randomized controlled trials comparing CHG and PVI antiseptic agents in patients aged ≥18 years with an underlying illness and a CVC or arterial catheter. The primary outcome was CRBSI rate. Network meta-analysis was performed by a frequentist-based approach with multi-variate random effects meta-analysis, and the effect size was expressed as relative risk (RR) with 95% confidence interval (CI).

FINDINGS

The search yielded 1511 records, of which five studies (2815 catheters) were included in the network meta-analysis. The risk of CRBSI was significantly lower with 1% CHG-alcohol than with 0.5% CHG-alcohol (RR 0.40, 95% CI 0.16-0.98; high certainty) or 10% PVI-aqueous (RR 0.31, 95% CI 0.15-0.63; high certainty). There was no significant difference in the risk of CRBSI between 1% CHG-alcohol and 2% CHG-aqueous (RR 0.35, 95% CI 0.12-1.04; moderate certainty) or other antiseptic solutions. The hierarchy of efficacy in reducing CRBSI was 1% CHG-alcohol, 0.5% CHG-alcohol, 2% CHG-aqueous and 10% PVI-aqueous.

CONCLUSION

Antiseptic agents containing 1% CHG-alcohol were more strongly associated with reduced risk for CRBSI compared with agents containing 0.5% CHG-alcohol or 10% PVI-aqueous.

Ancient Jomon genome sequence analysis sheds light on migration patterns of early East Asian populations

Anatomically modern humans reached East Asia more than 40,000 years ago. However, key questions still remain unanswered with regard to the route(s) and the number of wave(s) in the dispersal into East Eurasia. Ancient genomes at the edge of the region may elucidate a more detailed picture of the peopling of East Eurasia. Here, we analyze the whole-genome sequence of a 2,500-year-old individual (IK002) from the main-island of Japan that is  characterized with a typical Jomon culture. The phylogenetic analyses support multiple waves of migration, with IK002 forming a basal lineage to the East and Northeast Asian genomes examined, likely representing some of the earliest-wave migrants who went north from Southeast Asia to East Asia. Furthermore, IK002 shows strong genetic affinity with the indigenous Taiwan aborigines, which may support a coastal route of the Jomon-ancestry migration. This study highlights the power of ancient genomics to provide new insights into the complex history of human migration into East Eurasia.

Takashi Gakuhari, Shigeki Nakagome et al. report the genomic analysis on a 2.5 kya individual from the ancient Jomon culture in present-day Japan. Phylogenetic analysis with comparison to other Eurasian sequences suggests early migration patterns in Asia and provides insight into the genetic affinities between peoples of the region.

P6466Novel index with combined echocardiographic parameter and CT parameter (pPAT) is useful for screening pulmonary hypertension in Systemic Sclerosis Patients

Background

Systemic sclerosis (SSc) patients with pulmonary arterial hypertension (PAH) had poor survival rate. Usual index of estimating PH is tricuspid regurgitate jet pressure gradient (TRPG). Accurate assessment of PAH is important for the management of SSc patients. However, estimated mean pulmonary arterial pressure (mPAP) using TRPG by echocardiography does not always reflect actual mPAP by right heart catheterization (RHC) in SSc patients. On the other hand, recent reports have shown that rPA, a ratio of diameter of pulmonary artery to ascending aorta (PA/Ao) calculated by computed tomography (CT), was associated with mPAP. However, both index are not sufficient for evaluation of PH. We hypothesized that the product of TRPG and rPA (pPAT) could estimate mPAP of SSc patients more accurately than TRPG or rPA.

Purpose

We investigated the usefulness of the product of TRPG and rPA for detecting actual mPAP in SSc patients.

Methods

Thirty-six SSc patients who suspected PH were enrolled retrospectively. We defined PH as resting mPAP from RHC of >25 mmHg. We measured both a widest pulmonary artery diameter and an adjacent ascending aorta diameter at the same level of the bifurcation of the main pulmonary artery using CT images.

Results

The average age was 67 years old and average mPAP by RHC was 24.7 mmHg. Mean TRPG and mean rPA were 35.1 mmHg and 1.06, respectively. Furthermore, mean pPAT was 37.9. We found pPAT had a stronger correlation with actual mPAP (r=0.848, p<0.001) than TRPG (r=0.754, p<0.001) or rPA (r=0.584, p<0.001). On ROC analysis, pPAT predicted PH with high accuracy for a cut-off of 33.1. In order to evaluate the usefulness of pPAT, we compared false-negative patients between two cutoff values of TRPG 34 mmHg described in ESC guideline and pPAT 33.1. Among the patients with TRPG <34mmHg, 4 patients (18%) had PH. In contrast, when screening PH using pPAT, the diagnosis of PH was missed in only one patient.

Figure 1

Conclusion

The product of TRPG and PA/Ao (pPAT) could be a novel and useful noninvasive index for identifying PH in SSc patients.

P5974Prognostic value of global tangential strain by three-dimensional echocardiography heart failure patients with intermediate ECG criteria for cardiac resynchronization therapy

Background

In the current clinical guidelines, cardiac resynchronization therapy (CRT) is recommended in heart failure (HF) patients with left bundle branch block (LBBB) with QRS width ≥150ms as Class I indication. In terms of HF patients with intermediate ECG criteria, prediction for benefit of CRT is still controversial in routine echocardiography.

Purpose

The aim was to assess whether three-dimensional (3D) echocardiographic indexes of global LV function at baseline has a prognostic value following CRT implantation in patients who fulfilled with intermediate ECG criteria.

Methods

We studied 62 HF patients who fulfilled with the indication criteria of CRT implantation according to current the clinical guidelines. In addition to routine two-dimensional echo, 3D echo dataset was acquired for determination of 3D global tangential strain (GTS) and 3D global longitudinal strain (GLS). We tracked predefined unfavorable outcomes for 3 years after CRT implantation: death, hospitalization due to worsening HF.

Results

LBBB with QRS width ≥150ms was evident in 26 of 62 patients (aged 68±11 years with 160±26 ms of QRS duration and 29±7% of LV ejection fraction), and the other 36 patients only fulfilled intermediate ECG criteria (QRS width 120–149ms or non-LBBB). Unfavorable events occurred in 21 patients (34%). The median GTS was −15.4%. Although GLS was not predictive, GTS greater than −15.4% had high probability of unfavorable outcomes over 3 years (Log-rank, p<0.05). There is no difference in the probability of unfavorable outcomes between LBBB and intermediate ECG criteria. Baseline GTS in patients with intermediate ECG criteria was associated with unfavorable outcomes: −12.6±2.6% vs. −17.3±3.8% (p<0.05). Outcome was better in the intermediate ECG criteria patients with GTS ≤−15.4% than in those with LBBB and in those with intermediate ECG criteria patients with GTS >−15.4% (Log-rank: p<0.05, p<0.0001, respectively).

Conclusions

Baseline GTS by 3D echocardiography is useful for predicting outcome over 3 years after CRT implantation regardless of the ECG criteria for CRT indication.

The prehistoric peopling of Southeast Asia

The human occupation history of Southeast Asia (SEA) remains heavily debated. Current evidence suggests that SEA was occupied by Hòabìnhian hunter-gatherers until ~4000 years ago, when farming economies developed and expanded, restricting foraging groups to remote habitats. Some argue that agricultural development was indigenous; others favor the “two-layer” hypothesis that posits a southward expansion of farmers giving rise to present-day Southeast Asian genetic diversity. By sequencing 26 ancient human genomes (25 from SEA, 1 Japanese Jōmon), we show that neither interpretation fits the complexity of Southeast Asian history: Both Hòabìnhian hunter-gatherers and East Asian farmers contributed to current Southeast Asian diversity, with further migrations affecting island SEA and Vietnam. Our results help resolve one of the long-standing controversies in Southeast Asian prehistory.

Motor and cognitive function analysis for home discharge using the Functional Independence Measure in patients undergoing cardiac rehabilitation at a long-term acute-care hospital

BACKGROUND

Although numerous studies on Functional Independence Measure (FIM) analysis in stroke, orthopedic disease, and spinal cord injury patients have been conducted, it has rarely been done in patients undergoing cardiac rehabilitation (CR).

AIM

To verify whether the Functional Independence Measure (FIM) score, and its subscale motor FIM and cognitive FIM, during inpatient CR can be a predictor of a patient's readiness for home discharge by establishing an FIM cutoff value.

DESIGN

A retrospective, observational cohort study

SETTING

This study was conducted at a long-term acute-care hospital.

POPULATION

Participants were in-hospital patients undergoing CR (N.=949).

METHODS

Measurements included motor FIM, cognitive FIM, CR period, FIM gain per week, and discharge disposition. The strongest predictor for home discharge was analyzed by using multiple logistic regression analysis, and the cutoff value of the FIM score for home discharge was determined by using receiver operating characteristic (ROC) curves.

RESULTS

Discharge to home was possible in 723 patients (76.2%), whereas 226 patients (23.8%) had other outcomes. In univariate analysis, a motor FIM gain per week of five points was achieved in the home discharge group. Multiple logistic regression analysis revealed that Body Mass Index, number of comorbidities, motor FIM at discharge, cognitive FIM gain, and CR period were predictive factors with 89.6% predictive ability. ROC curve analysis showed that the cutoff value was a discharge motor FIM score of 63/64 points with 0.912 areas under the curve.

CONCLUSION

Discharge motor FIM and cognitive FIM gain were predictive factors for home discharge. A motor FIM gain per week of five points and discharge motor FIM score of 64 points at the end of inpatient CR may be important predictors of a patient's readiness for discharge to home.

CLINICAL REHABILITATION IMPACT

The findings of this study indicate an alternative goal to the activities of daily living in inpatients with cardiovascular disease.

Chronic toxicity and carcinogenicity of N-[N-[3-(3-hydroxy-4-methoxyphenyl) propyl]-α-aspartyl]-L-phenylalanine 1-methyl ester, monohydrate (advantame) in the rat

Groups of 55 male and 55 female Han Wistar rats were administered advantame (98.9-99.8% purity) in the diet at concentrations of 0, 2000, 10,000, or 50,000 ppm for 104 weeks, following parental exposure to the same levels from prior to mating and throughout gestation. Additional groups of 20 rats/sex and 10 rats/sex were dosed for a period of 52 weeks and constituted the toxicity and reversibility phases of the study. Achieved doses of advantame over the carcinogenicity study were 0, 97, 488, and 2621 mg/kg body weight/day in males and 0, 125, 630, and 3454 mg/kg body weight/day in females, respectively. A high incidence of a pale and swollen anus and changes in fecal composition were observed in the high-dose groups. There was no effect of treatment on mortality. Body weight gain in the high-dose males (50,000 ppm) was slightly reduced compared to controls after 52 and 104 weeks of treatment; the decrease was not considered to be of toxicological significance, but due to the non-nutritive nature of the high dietary concentration of advantame. During the toxicity phase, food conversion efficiency was slightly decreased in both sexes, at the 50,000 ppm dose level. Given the non-nutritive content of the diet, this finding was not considered biologically significant. There were no relationships between treatment and the results of hematological or urinalysis investigations. Clinical chemistry evaluations showed consistently lower plasma urea concentrations in both sexes treated at 50,000 ppm, which was reversed during the 6-week recovery phase following 52 weeks of treatment, indicating a lack of permanent effects. Terminal investigations at both the 52 and 104-week revealed a number of intergroup differences in absolute and/or relative organ weights; however, the differences did not show dose-response relationships, were minor in nature, and/or occurred only in one sex, and were not associated with any pathological findings, and they were considered not to be treatment-related. Evaluation of the histopathology of the carcinogenicity phase animals revealed an increased incidence of pancreatic islet cell carcinomas in males (incidence rates of 0/55, 1/55, 2/55, and 3/55 in the 0, 2000, 10,000, or 50,000 ppm groups, respectively) and of mammary gland adenomas in the high-dose females (incidence rates of 0 in the control through 10,000 ppm dose groups and 4/41 in the 50,000 ppm dose group). The incidence rates of these tumors did not attain statistical significance and/or remained within background historical control values, and they were considered to be unrelated to advantame treatment. The no-observed-adverse-effect level was considered to be 50,000 ppm in the diet, the highest concentration tested, equivalent to 2621 and 3454 mg/kg body weight/day in males and females, respectively. Advantame was concluded to be without carcinogenic activity.

In vitro and in vivo assessment of the mutagenic activity of N-[N-[3-(3-hydroxy-4-methoxyphenyl) propyl]-α-aspartyl]-L-phenylalanine 1-methyl ester, monohydrate (advantame)

Advantame (N-[N-[3-(3-hydroxy-4-methoxyphenyl) propyl]-α-aspartyl]-L-phenylalanine 1-methyl ester, monohydrate), an N-substituted analogue of aspartame, has been developed as a high-intensity sweetener. It is approximately 100 and 20,000 times sweeter than aspartame and sucrose, respectively. In this study the safety of advantame has been evaluated using a series of in vitro and in vivo genotoxicity assays including, bacterial mutation, mammalian cell mutation, and mouse micronucleus tests. Advantame did not induce reverse mutations in Salmonella typhimurium and Escherichia coli at concentrations of up to 5000 μg/plate. In the mammalian cell mutation assay, advantame did not induce mutation at the Hprt locus of L5178Y mouse lymphoma cells in two independent experiments, either in the absence or presence of S9. In vivo, there was no effect on the incidence of micronucleated immature or mature erythrocytes in bone marrow after oral administration of the test substance at any dose level (up to 2000 mg/kg body weight) or sampling time (24 and 48 h). The results of these studies demonstrate that advantame is without genotoxic potential.

A two-generation reproductive toxicity study of the high-intensity sweetener advantame in CD rats

Rats received diets containing 0, 2000, 10,000, or 50,000 ppm advantame (N-[N-[3-(3-hydroxy-4-methoxyphenyl) propyl]-α-aspartyl]-L-phenylalanine 1-methyl ester, monohydrate) for 2 generations. F(0) animals (30/sex/group) were treated from 10 weeks before pairing. Males continued until week 16; females through gestation and lactation. Once weaned, F(1) animals (25/sex/group) continued receiving the same diet until F(2) pups were weaned. Mean advantame intakes from each of the diets were 164, 833, and 4410 mg/kg bw/day among F(0) males, and 204, 1036, and 5431 mg/kg bw/day among F(1) males. F(0) and F(1) females had comparable intakes up to lactation, when intakes increased (up to 8447 mg/kg bw/day from 50,000 ppm diet). No treatment-related effects on mortality, body weights, reproduction, litter observations, or postnatal offspring development were noted. Atypical coloration of the feces and cage liners seen with test diets was attributed to excretion of test material/metabolites in the feces and urine. Slightly higher food consumption was seen in F(0) and F(1) animals, especially males, receiving 50,000 ppm. However, these differences were considered to be a secondary response to the high levels of non-nutritive material in the diet. The no-observed-adverse-effect level for reproductive and developmental toxicity was considered to be 50,000 ppm, the highest dietary concentration tested.

Pressure-derived collateral flow index as a parameter of microvascular dysfunction in acute myocardial infarction

OBJECTIVES

The goal of this study was to examine the implications of the pressure-derived collateral flow index (CFIp) in acute myocardial infarction (AMI).

BACKGROUND

Higher CFIp is associated with less severe myocardial ischemia during angioplasty in the non-infarcted heart. It remains unknown whether CFIp also identifies collateral function in AMI patients with and without no-reflow phenomenon.

METHODS

The study population included 48 patients with a first AMI. After successful percutaneous transluminal coronary angioplasty (PTCA) stent, we measured mean aortic pressure (Pa), central venous pressure (Pv) and coronary wedge pressure (Pcw) of the infarct-related artery to calculate: CFIp = (Pcw - Pv)/(Pa - Pv). Myocardial contrast echocardiography (MCE) was performed with the intracoronary injection of microbubbles to assess myocardial perfusion. Left ventriculograms at days 1 and 28 were provided for the measurement of the regional wall motion (RWM, SD/chord).

RESULTS

There was no difference in CFIp among subsets based on angiographic collateral grades (grade 0, 1, 2, 3; 0.28 +/- 0.07, 0.27 +/- 0.09, 0.27 +/- 0.08, 0.23 +/- 0.08, p = NS). The CFIp was significantly higher in patients with MCE no-reflow (n = 16) than in those with MCE reflow (n = 32) (0.34 +/- 0.07 vs. 0.23 +/- 0.06, p < 0.01). There was a significant inverse correlation between the extent of functional improvement (DeltaRWM[28 d-1 d]) and CFIp (r = 0.56, p < 0.01), implying that higher CFIp is associated with worse functional improvement.

CONCLUSIONS

In AMI, CFIp is unlikely to reflect collateral function but seems to increase with the severity of microvascular dysfunction. Because higher CFIp was associated with poorer functional recovery, it provides a simple and useful estimate of clinical outcomes in AMI.

Long-term administration of amlodipine prevents decompensation to diastolic heart failure in hypertensive rats

OBJECTIVES; We assessed the effects of long-term amlodipine administration in a diastolic heart failure (DHF) rat model with preserved systolic function as well as the relationship between changes in left ventricular (LV) myocardial stiffening and alterations in extracellular matrix.

BACKGROUND

Although the effect of long-term administration of amlodipine has been shown to be disappointing in patients with systolic failure, the effect is unknown in those with DHF.

METHODS

Dahl salt-sensitive rats fed a high-salt diet for seven weeks were divided into three groups: eight untreated rats (DHF group), eight rats given high-dose amlodipine (10 mg/kg/day; HDA group) and seven rats given low-dose amlodipine (1 mg/kg/day; LDA group).

RESULTS

High-dose administration of amlodipine decreased systolic blood pressure and controlled excessive hypertrophy, without a decrease in the collagen content, and prevented the elevation of LV end-diastolic pressure at 19 weeks. Low-dose administration of amlodipine with subdeppressive effects did not control either hypertrophy or fibrosis; however, it prevented myocardial stiffening and, hence, the elevation of LV end-diastolic pressure. The ratio of type I to type III collagen messenger ribonucleic acid levels was significantly lower in both the HDA and LDA groups than in the DHF group.

CONCLUSIONS

Long-term administration of amlodipine prevented the transition to DHF both at the depressor and subdepressor doses. Amlodipine did not decrease the collagen content, but attenuated myocardial stiffness, with inhibition of the phenotype shift from type III to type I collagen. Thus, amlodipine may exert beneficial effects through amelioration of collagen remodeling in the treatment of DHF.

Ventricular production of natriuretic peptides and ventricular structural remodeling in hypertensive heart failure

OBJECTIVES

Brain natriuretic peptide (BNP) is a strong predictor of left ventricular (LV) hypertrophy (LVH) and dysfunction. However, our recent studies suggested that LVH is not necessarily associated with enhanced production of BNP in hypertension. This study aimed to clarify the relation of the characteristics of hypertrophy with the degree of gene expression of BNP in the developmental process of hypertensive heart failure.

METHODS

Serial changes in LV geometry, histology and atrial natriuretic peptide (ANP) and BNP mRNA levels, were assessed in a hypertensive heart failure model using Dahl salt-sensitive rats (n = 24). We further studied effects of alpha1-receptor antagonist (doxazosin: 1 mg/kg per day, n = 5) and angiotensin II type 1 receptor (AT1R) antagonist (candesartan cilexetil: 1 mg/kg per day, n = 5).

RESULTS

The BNP mRNA level was not elevated at the compensatory hypertrophic stage when ANP mRNA level was elevated. BNP mRNA level was increased with further progression of hypertrophy and development of fibrosis. AT1R blockade prevented such fibrosis and further progression of hypertrophy with normalization of BNP mRNA levels. Compensatory hypertrophy was not suppressed; therefore, ANP mRNA level, although decreased, was still beyond the normal level. The alpha1-receptor blockade slightly attenuated LV hypertrophy with a slight decrease in ANP mRNA levels. LV fibrosis was not prevented, and the BNP mRNA level was not decreased.

CONCLUSIONS

BNP gene expression is not enhanced by initial compensatory hypertrophy, but is enhanced by LV fibrosis and late stage progression of hypertrophy dependent on AT1R-mediated signaling pathway.

[Anesthetic management of a patient with Dyggve-Melchior-Clausen syndrome]

The Dyggve-Melchior-Clausen syndrome (DMCS) is a rare autosomal recessive skeletal dysplasia characterized by short-trunk dwarfism and mental retardation. A 49-year-old male with DMCS underwent resection arthroplasty for contracture of the right hip joint under general anesthesia using thiamylal, nitrous oxide, sevoflurane, and vecuronium. Although he was assumed to have difficult airway due to short neck, macroglossia, and disturbance of neck flexion, tracheal intubation was not difficult. No complications including malignant hyperthermia were observed during the 95 min of the operation.

Dynamic change in collateral flow associated with myocardial ischemia in humans

BACKGROUND

This study sought to investigate how collateral flow changes during myocardial ischemia in patients.

METHODS

Myocardial contrast echocardiography (MCE) and rapid atrial pacing were performed in 20 patients with angiographically evidenced coronary collaterals from the right coronary artery (RCA) to the occluded left anterior descending coronary artery. Sonicated contrast medium was injected into the RCA before and immediately after atrial pacing to determine the peak background-subtracted contrast intensity (PI) in the collateral territory (PIA) and its ratio to PI in the control territory (PI ratio) as parameters of collateral blood flow. Lactate production in the coronary circulation during pacing was determined to assess myocardial ischemia in the collateral territory.

RESULTS

PIA showed a significant correlation with regional wall motion either before (r(squared)=-0.64, P<0.01) or after pacing (r(squared)=-0.65, P<0.01). Similarly, PI ratio was significantly correlated with regional wall motion either before (r(squared)=-0.54, P<0.05) or after pacing (r(squared)=-0.64, P<0.01). Rapid atrial pacing decreased both PIA and PI ratio significantly greater in patients with lactate production than in those without (PIA: -67+/-53 vs. -15+/-34%, P<0.05; PI ratio: -68+/-49 vs. -8.2+/-32%, P<0.05, respectively), while neither PIA nor PI ratio differ between the two groups of patients before pacing (PIA: 13.8+/-19. vs. 16.2+/-13.3U, P=0.75; PI ratio: 0.70+/-0.71 vs. 0.87+/-0.65, P=0.58, respectively).

CONCLUSIONS

We concluded that (1) collateral flow determined by MCE was closely associated with regional cardiac function, and (2) not the amount of collateral flow at rest, but pacing-induced change of collateral flow seemed to be a determinant of regional ischemia in patients with coronary collaterals.

Determination of coronary zero flow pressure by analysis of the baseline pressure-flow relationship in humans

The present study seeks to estimate the difference between coronary zero flow pressure (Pzf) by analysis of the baseline pressure-flow relationship and the Pzf calculated during a long diastole in humans. Although Pzf is likely to provide meaningful information about the characteristics of coronary circulation, there are no available data on Pzf in humans because Pzf is overestimated when it is calculated during normal cardiac cycles. Actual Pzf was determined in 15 subjects by analyzing the coronary pressure-flow relationship during a long cardiac cycle induced by an intracoronary adenosine triphosphate (ATP) infusion, and it was compared with the Pzf calculated during a normal cardiac cycle in order to estimate the difference. Pzf calculated during a normal cardiac cycle was 47 +/- 15 mmHg, which decreased to 36 +/- 9mmHg after intracoronary administration of ATP (0.05 mg) whereas actual Pzf was 21 +/- 7 mmHg. Pzf calculated in a pressure-flow relationship during a normal cardiac cycle under vasodilation correlated well with that during a long diastole (r = 0.75, p < 0.01), although it was 15 +/- 6 mmHg greater than the actual Pzf. It was concluded that Pzf during a normal cardiac cycle could be used to anticipate Pzf.

Prediction of wall motion recovery from the left anterior descending coronary artery velocity pattern recorded by transthoracic doppler echocardiography in patients with anterior wall myocardial infarction retrospective and prospective studies

The diastolic deceleration slope of coronary flow velocity is steeper in patients with substantial 'no reflow' phenomenon than in those without it. This study investigated whether functional outcomes in patients with anterior wall acute myocardial infarction (AMI) can be predicted by analyzing the coronary flow velocity pattern recorded with transthoracic Doppler (TTD) echocardiography. Coronary blood flow velocity in the distal left anterior descending coronary artery was recorded with TTD at day-2 after primary percutaneous transluminal coronary angioplasty/Stent in 51 patients with anterior AMI and the diastolic deceleration half time (DHT, ms) was measured. The wall motion score index (WMSI) was measured at day-1 and -21. In the retrospective study, the DHT was much shorter in those with a poor outcome than in those with good outcome (152 +/- 109 vs 395 +/- 128 ms, p<0.05). Receiver-operating characteristic analysis documented that DHT > or = 300 ms is a suitable cut-off point (sensitivity of 83% and specificity of 93%). In the prospective study (n=30), AWMSI(dl-d21) was significantly higher in those with a DHT > or = 300 ms than those without (0.3 > or = 0.5 vs 1.6 > or = 0.7, p<0.001). DHT correlated significantly with AWMSI(dl-d21) (r=0.76, p<0.001). Patients with a shorter DHT of diastolic coronary flow velocity have a poorer functional outcome among patients with anterior AMI. The TTD-determined DHT is a useful predictor of myocardial viability after an anterior AMI.

Renin angiotensin system-dependent hypertrophy as a contributor to heart failure in hypertensive rats: different characteristics from renin angiotensin system-independent hypertrophy

OBJECTIVES

This study aimed to characterize the difference between renin angiotensin system (RAS)-dependent and RAS-independent hypertrophy and their differential contribution to the transition to heart failure.

BACKGROUND

Hypertensive left ventricular (LV) hypertrophy develops with RAS activation in the heart; however, LV hypertrophy develops even without RAS activation.

METHODS

Left ventricular geometry and function were assessed in Dahl salt-sensitive rats placed on an 8% NaCl diet from seven weeks old (hypertensive rats) and in those placed on an 0.3% NaCl diet (control rats, n = 8). The hypertensive rats were randomized to no treatment (n = 8) or treatment with the angiotensin type 1 receptor (AT1R) antagonist candesartan (1 mg/kg per day, n = 10) after the baseline echocardiography study.

RESULTS

From 7 to 13 weeks, AT1R blockade at a subdepressor dose did not restrain the development of LV hypertrophy but prevented narrowing of LV diastolic dimension, leading to the normalization of abnormally decreased end-systolic wall stress in the untreated rats. Progressive development of LV hypertrophy in spite of lower than normal end-systolic wall stress (excessive hypertrophy) after 13 weeks was suppressed by the AT1R blockade. Elevation of LV end-diastolic pressure and prolongation of Tau were associated with histological evidence of myocyte hypertrophy and massive interstitial fibrosis in the untreated rats, and none of these was evident in the treated rats.

CONCLUSIONS

Renin-angiotensin system activation and AT1R signaling may be dispensable for the development of early adaptive LV hypertrophy and closely linked to the transition to heart failure.

Evolving changes in Doppler mitral flow velocity pattern in rats with hypertensive hypertrophy

OBJECTIVES

The aim of our study was to explore evolving changes in a mitral flow velocity pattern (MFVP) and its hemodynamic and pathological correlates in hypertensive rats in an isolated diastolic heart failure model.

BACKGROUND

Development of left ventricular (LV) hypertrophy and concomitant diastolic dysfunction cause heart failure in hypertensive hearts even with normal systolic function; however, associated evolving change in MFVP is still unclear.

METHODS

Mitral flow velocity pattern was recorded every 2 weeks from 7 to 19 weeks in six hypertensive rats. Hemodynamic and pathological correlates of Doppler mitral flow indexes were examined as an additional part of the study using the hypertensive rats at the age of 13 weeks (compensatory stage, n = 7) and at 19 weeks (heart failure stage, n = 8).

RESULTS

Initial development of pressure overload LV hypertrophy resulted in a decrease in early diastolic filling wave (E), a reciprocal increase in the filling wave due to atrial contraction (A) and prolongation of deceleration time of E wave (relaxation abnormality pattern). These changes were associated with an increase in tau, an index of LV relaxation, but without a change in LV end-diastolic pressure. Transition to congestive heart failure caused an increase in E, a decrease in A and shortening of deceleration time. These changes were not associated with further increase in tau but with elevation of LV end-diastolic pressure, reflecting marked LV hypertrophy and myocardial fibrosis.

CONCLUSIONS

Development of pressure overload LV hypertrophy is associated with evolving changes in MFVP from normal to relaxation abnormality pattern and, in turn, to pseudonormalized to restrictive pattern. Analysis of MFVP may be useful to follow not only functional but also constitutional changes of the myocardium in hypertensive hearts.

Calcineurin inhibitor attenuates left ventricular hypertrophy, leading to prevention of heart failure in hypertensive rats

BACKGROUND

There is controversy regarding the contribution of calcineurin activation to the development of pressure-overload left ventricular (LV) hypertrophy and heart failure. The aim of this study was to explore whether the inhibition of calcineurin may prevent the transition to heart failure in hypertensive rats and, if so, to clarify in which developmental stage of LV hypertrophy calcineurin plays a key role.

METHODS AND RESULTS

Dahl salt-sensitive rats placed on an 8% NaCl diet from the age of 7 weeks (hypertensive rats) were randomized to no treatment (n=6) or treatment with the calcineurin inhibitor FK506 (1 mg x kg(-1) x d(-1)) from 8 weeks (FKE, n=7) or from 17 weeks (FKL, n=7). Rats placed on a 0.3% NaCl diet were defined as control rats (n=6). The administration of FK506 from 8 weeks attenuated, although it did not block, LV hypertrophy observed in the untreated rats and prevented the transition to heart failure. The development of LV fibrosis, however, was not attenuated by the administration of FK506 from 8 weeks. The administration of FK506 from 17 weeks brought no benefit for cardiac remodeling or LV function and failed to prevent heart failure.

CONCLUSIONS

Calcineurin inhibition, if started from the initial stage of pressure overload, attenuated the development of LV hypertrophy without any effect on LV fibrosis and prevented the transition to heart failure. The activation of calcineurin is involved in the development of LV hypertrophy but not of LV fibrosis, and this involvement may be crucial at the initial stage.

Myocardial longitudinal motion by tissue velocity imaging in the evaluation of patients with myocardial infarction

Left ventricular (LV) longitudinal shortening plays an important role in cardiac contraction and is invariably affected by the presence of coronary artery disease. Third-generation tissue velocity imaging (TVI) color-maps cardiac movement by obtaining mean velocities of LV segments from the same set of beats. The goals of this study were to characterize patterns of longitudinal myocardial motion velocity in healthy subjects and to use these patterns to evaluate abnormal segments of patients with myocardial infarction (MI). Included were 20 healthy subjects and 16 patients with MI who underwent a 2-dimensional Doppler echocardiography study. Myocardial velocity profiles were taken at the anulus, basal, mid, and apical segments of the septal and lateral walls in the apical view. Segmental velocity patterns from healthy subjects were compared with abnormal segments in patients with MI. Both lateral and septal walls of healthy subjects showed significant basal-apical myocardial velocity reductions in systolic shortening (Sm) and early and late diastolic lengthening (Em and Am) and a basal-apical increase in the Em/Am ratio. The lateral wall had greater Sm and Em velocities than the septal wall. The Sm and Em velocities and the Em/Am ratio were significantly reduced in the abnormal segments in patients with MI. Latent lateral wall ischemia may have been detected in 5 of 9 patients with septal infarction, showing reduced Sm velocity in apparently normal lateral walls. In conclusion, TVI objectively quantifies directional and incremental changes in myocardial movement that are useful in evaluating global and regional myocardial function, and it may play a role in the detection of early myocardial ischemia.

Quantitative ultrasonic tissue characterization can identify high-risk atherosclerotic alteration in human carotid arteries

BACKGROUND

Recently, ultrasonic tissue characterization of the composition of plaques has been performed in a quantitative fashion on the basis of integrated backscatter (IBS) analysis, but most of those studies have used high-frequency ultrasound to obtain microscopic images.

METHODS AND RESULTS

We performed B-mode measurement and IBS signal analysis with acoustic densitometry with a 7.5-MHz linear-array transducer in freshly excised human aortas (n=58) (normal, atheromatous, and fibrous tissue) obtained at autopsy. Atheromatous and fibrous tissue had a similar intima-media thickness (IMT), but the IBS value in atheromatous specimens was lower than that in fibrous specimens. We further applied this method to human carotid ultrasonography. The subjects were young (80 regions), middle aged with 1 or no coronary risk factors (low risk) (120 regions), middle aged with >/=2 coronary risk factors (high risk) (240 regions), or elderly (80 regions) or were patients with myocardial infarction (MI) with multivessel disease (90 regions). The IMT was similar in middle-aged, elderly, and MI subjects. In contrast, the IBS value was significantly higher in elderly subjects and lower in high-risk middle-aged and MI subjects compared with that in low-risk middle-aged subjects. The percent of regions diagnosed as atheromatous (IBS less than mean minus 2-SD value of IBS in young subjects) was 11% in low-risk middle-aged subjects, 29% in high-risk middle-aged subjects, and 63% in the MI group.

CONCLUSIONS

In conjunction with conventional B-mode imaging, IBS analysis with carotid ultrasonography appeared to provide prognostic information to identify a high-risk group with systemic atherosclerosis, which could lead to coronary heart disease in individuals with early-stage disease.

Roles of renin-angiotensin and endothelin systems in development of diastolic heart failure in hypertensive hearts

OBJECTIVE

Although interest in diastolic heart failure is growing because of its clinical frequency, little is known about this type of heart failure. Our laboratory recently developed a diastolic heart failure model using Dahl salt-sensitive rat. In this model, gene expression of angiotensin-converting enzyme and endothelin (ET) system in the left ventricle was enhanced at heart failure stage without downregulation of angiotensin type 1a receptor mRNA level. However, the roles of these humoral systems in the transition to diastolic failure remain unclear.

METHODS

Subdepressor doses of angiotensin II type 1 (AT1) receptor and ET type A (ETA) receptor antagonists were administered in this model just after onset of hypertension, and their effects were investigated.

RESULTS

Neither AT1 nor ETA receptor blockade inhibited the early (13 weeks) compensatory left ventricular (LV) hypertrophy. This form of compensatory hypertrophy is associated with subnormal LV end-systolic stress, which was normalized by AT1 receptor blockade but not by ETA receptor blockade. Progression of LV hypertrophy and fibrosis and transition to heart failure (19 weeks) in the untreated rats were prevented by both antagonists, resulting in normalization of LV end-diastolic pressure and lung weight. AT1 receptor blockade, but not ETA receptor blockade, normalized time constant of LV relaxation. Enhanced gene expression for ET system in the left ventricle observed in the untreated rats was suppressed with AT1 receptor antagonist administration. ETA receptor blockade slightly but significantly elevated the AT1a receptor mRNA level as compared with the untreated rats.

CONCLUSIONS

RAS and ET system contribute to the transition to diastolic heart failure through the development of excessive hypertrophy and ventricular fibrosis in hypertensive heart diseases, however, neither RAS nor ET system is mandatory for normal compensation for pressure overload. RAS apparently causes such diastolic effects at least partly through the ET system.

High-frame-rate tissue harmonic imaging enhances anatomic M-mode sections of the left ventricle in short-axis view

BACKGROUND

High-frame-rate echocardiography (HFRE) and tissue harmonic imaging (THI) may improve image quality, thereby enabling anatomic M-mode sections of left ventricular (LV) wall segments to be visualized in various planes in the short-axis view.

OBJECTIVES

The goals of this study were to compare image quality between HFRE and conventional-frame-rate echocardiography (CFRE) and between fundamental imaging (FI) and THI, and to obtain anatomic M-mode values of basal short-axis LV segments from healthy subjects for use in the evaluation of abnormal segments in patients with myocardial infarction (MI).

METHODS AND RESULTS

The study included 28 healthy subjects and 15 patients with MI who underwent 2-dimensional echocardiography with an ultrasonographic system equipped with THI and anatomic M-mode. Left ventricular image cineloops at the basal short-axis view that were obtained with 3 combinations of imaging techniques (FI + CFRE, FI + HFRE, and THI + HFRE) were digitized and displayed side-by-side in random order for comparison by blinded readers. M-mode sections were done in 3 planes: anteroseptal-posterior, inferoseptal-lateral, and anterior-inferior basal segments. The THI + HFRE combination showed the best image quality with significant reduction in noise artifacts, resulting in a good signal-to-noise ratio and good tractability of all LV segments by anatomic M-mode. In healthy subjects, significant intersegmental differences existed in the diastolic and systolic thicknesses and in the percent systolic thickening of LV segments. In patients with MI, LV systolic thickening was significantly decreased in abnormal segments. No significant differences were noted in ejection fraction and fractional shortening among the 3 anatomic M-mode planes.

CONCLUSION

High-frame-rate tissue harmonic imaging improved image quality, thereby allowing reproducible anatomic M-mode measurements in various planes in the short-axis view and providing a convenient objective evaluation of global and regional LV function.

An improved genetic linkage map of rat chromosome 20

BACKGROUND AND PURPOSE

Rat chromosome 20 is one of special interest because it contains some diabetogenic genes, such as a major histocompatibilitiy complex (MHC)-linked genetic components and quantitative trait loci. We studied rat chromosome 20, using the backcross progeny between BB/Wor and PVG.R23 rats, and confirmed the genetic linkage map by use of another backcross panel.

METHODS

Backcross panels were done between BB/Wor and PVG.R23 rats, and BN and KZC rats. Length variations of simple sequence length polymorphism markers were analyzed by use of polymerase chain reaction (PCR) analysis. Alleles of RT1-Bb and RT1-Db were analyzed by use of the PCR-restriction fragment length polymorphism method. Genetic maps of rat chromosome 20 were constructed, using the Map Manager computer program.

RESULTS

Fifty-two loci were mapped on rat chromosome 20. Genetic length was 57.9 cM, with average spanning of 1.11 cM between markers. The positions of RT1-N1, Tnf, and RT1-Bb into the MHC region were separated and confirmed by results of two backcross panels in our linkage studies.

CONCLUSIONS

The genetic linkage map of rat chromosome 20 was improved, and was a useful tool for genetic analysis of a diabetogenic gene(s) and for producing MHC congenic strains.

Local neurohumoral regulation in the transition to isolated diastolic heart failure in hypertensive heart disease: absence of AT1 receptor downregulation and 'overdrive' of the endothelin system

OBJECTIVE

Although isolated diastolic heart failure with preserved left ventricular (LV) systolic function frequently occurs, regulation of local neurohumoral factors in the transition from diastolic dysfunction without signs of heart failure to diastolic failure, a target for therapeutic strategy, remains to be clarified, partly because of a lack of animal models. Our laboratory recently demonstrated that Dahl-Iwai salt-sensitive (Dahl-S) rats fed on a high-salt diet since 7 weeks of age develop hypertension followed by compensated LV hypertrophy at 13 weeks and transition to isolated diastolic heart failure at 19 weeks.

METHODS

Gene expression of the components of the renin-angiotensin system, endothelin (ET) system and natriuretic peptide system in the left ventricle was investigated in the transition to isolated diastolic heart failure in this model.

RESULTS

The compensated ventricular hypertrophy was associated with slight increases in angiotensin-converting enzyme (ACE) and angiotensin II type-1a (AT1a) receptor mRNA levels. Although preproET-1 (ppET-1) and ET-converting enzyme-1 (ECE-1) mRNA levels were not increased, mRNA levels of ET type-A (ETA) and ET type-B (ETB) receptors were increased. Atrial natriuretic peptide (ANP) mRNA level increased, but not brain natriuretic peptide (BNP) mRNA level. At the decompensated failing stage (at 19 weeks), ACE mRNA level further increased without downregulation of ATla receptor mRNA level. The mRNA levels of ppET-1 and ECE-1 increased with persistent upregulation of mRNA levels of ETA and ETB receptors, and immunohistochemical staining for ET-1 was found at endothelial cells and myocytes. BNP mRNA level increased with a further increase in ANP mRNA level.

CONCLUSIONS

The transition to isolated diastolic heart failure in hypertrophied hearts was associated with preserved gene expression of the renin-angiotensin system and 'overdrive' of gene expression of the ET system. BNP gene expression is likely to be activated by the progression of diastolic failure rather than by LV hypertrophy alone.

Use of echocardiography for predicting myocardial viability in patients with reperfused anterior wall myocardial infarction

Dobutamine stress echocardiography (DSE), myocardial contrast echocardiography (MCE), and ultrasonic tissue characterization with integrated backscatter are useful methods for assessing myocardial viability in acute myocardial infarction. In this study, we compared the potential of 3 methods for predicting myocardial viability in 38 patients with reperfused anterior wall acute myocardial infarction. We performed MCE shortly after coronary reperfusion with an intracoronary injection of microbubbles. We recorded 2-dimensional integrated backscatter images at rest and, then, performed low-dose (10 microg/kg/min) DSE 3 days later. In integrated backscatter images, we placed the region of interest in the midwall of the myocardial segment to reconstruct the cyclic variation of myocardial integrated backscatter. The myocardial segment was judged viable when it showed active contraction 3 months later. Among 74 segments analyzed, 34 were judged viable. Presence of contractile response during DSE predicted segmental viability with 91% sensitivity and 78% specificity. Intense and homogenous contrast enhancement with MCE predicted viability with 82% sensitivity and 73% specificity. The presence of synchronous contraction of cyclic variation predicted myocardial viability with 79% sensitivity and 83% specificity. There were no differences in sensitivity and specificity among the 3 methods. Thus, MCE and ultrasonic tissue characterization can predict myocardial viability as accurately as DSE in patients with acute myocardial infarction. The logistics of the methods may determine clinical application.

[Intravenous contrast echocardiography]

Intravenous contrast echocardiography has become possible in Japan because of the release of the commercially available contrast agent, Levovist. Intravenous administration of Levovist satisfactorily stains the left ventricular cavity, which makes it possible to clearly delineate the endocardial border. Clear delineation of the endocardial border provides easy and accurate measurement of left ventricular dimension and wall thickness, and wall motion abnormalities can be easily and accurately judged, too. Another benefit of intravenous contrast echocardiography is the assessment of myocardial perfusion. Our preliminary experimental and clinical experiences showed the possibility of myocardial staining with intravenous contrast echocardiography. Impressive myocardial staining is obtainable with the combined use of intermittent and contrast harmonic power Doppler imaging. In order to obtain reproducible and clear myocardial contrast images, we have to pay attention to how to inject contrast and settings of ultrasound equipment, i.e., mechanical index, gain setting, depth of focus point, and pulse repetition frequency, artifacts. In the near future, a lot of issues should be standardized to make it possible to compare myocardial contrast echo studies.

[Clinical implications of ultrasonic tissue characterization for atherosclerotic carotid intima-media]

Current imaging modalities, such as ultrasonic tissue characterization, have enabled accurate determination of the composition of atherosclerotic plaque of excised aortic tissue. The aim of this study is to compare integrated backscatter (IBS) echo signals of the intima-media complex of human carotid arteries between young and elderly subjects, and to evaluate the ability of ultrasonic tissue characterization. We compared the difference in ultrasonic parameters between the carotid arteries of young healthy subjects (n = 27, 25 +/- 1 y.o.) and elderly subjects (n = 55, 75 +/- 4 y.o.). Intima-media thickness (IMT) and calibrated IBS value (C-IBS: Tissue IBS-vessel lumen IBS value) were measured. The IMT values of young and elderly subjects were 0.54 +/- 0.03 and 1.08 +/- 0.07 mm, respectively (p < 0.01). C-IBS of elderly subjects (11.7 +/- 0.8 dB) was significantly higher than that of young subjects (6.9 +/- 0.7 dB). Significantly wider standard deviation of C-IBS value in each individual was observed in elderly subjects (mean +/- SE of individual standard deviation in C-IBS: 4.2 +/- 0.9 dB) compared with that in young subjects (1.7 +/- 0.3 dB). This might reflect varied composition of atherosclerotic plaques in elderly subjects. IBS analysis would become a promising method to distinguish plaque composition quantitatively and to assess the stability of plaques in clinical setting.

Development of different phenotypes of hypertensive heart failure: systolic versus diastolic failure in Dahl salt-sensitive rats

OBJECTIVE

There are two phenotypes of heart failure, systolic failure and isolated diastolic heart failure with preserved left ventricular systolic function. Although isolated diastolic heart failure frequently occurs, there are only models for diastolic dysfunction unassociated with heart failure and models with overt diastolic heart failure have not been established. We attempted to develop two different models, i.e. diastolic and systolic failure models, based on hypertension.

MATERIALS AND METHODS

Dahl salt-sensitive rats were placed on 8% NaCl diet from 7 weeks old (7-week starting group) or 8 weeks old (8-week starting group). As an age-matched control, Dahl salt-sensitive rats were consistently placed on normal chow. In these rats, echocardiogram was serially recorded, followed by hemodynamic and histological studies.

RESULTS

The 7-week starting rats showed a steep elevation in blood pressure and progressive left ventricular hypertrophy, and fell into overt heart failure at approximately 19 weeks. The development of heart failure was not associated with a decrease in left ventricular midwall fractional shortening or an increase in left ventricular end-diastolic dimension as compared with the age-matched control, which mimics the characteristics of clinically observed isolated diastolic heart failure. The 8-week starting rats showed a gradual rise in blood pressure and less progressive left ventricular hypertrophy, and fell into heart failure at approximately 26 weeks with a decrease in mid-wall fractional shortening and an increase in left ventricular end-diastolic dimension. Hemodynamic and histological studies at failing stage revealed comparable elevation of left ventricular end-diastolic pressure and comparable left ventricular fibrosis in both groups.

CONCLUSION

These two different models of overt heart failure may be useful as models of isolated diastolic heart failure and systolic heart failure based on the same hypertensive heart disease, respectively, and may contribute to discrimination of the mechanisms of the development of the two different phenotypes of heart failure.