Practical Experiences and Lessons of Medical Response to Major Disasters in China

Introduction

The construction of a medical emergency response system for disasters, which plays an important role in medical emergency response to multiple catastrophic events, has been sped up in China since the 2008 Wenchuan earthquake. However, the implementation process has also exposed some problems, particularly the disaster relief system.

Methods

In this review, we summarised and analysed emergency medical rescue efforts after major disasters in China in recent years, including 2008 Wenchuan earthquake, 2010 Yushu earthquake, ‘7.23’ Yongwen major railway line accident and 2013 Lushan earthquake.

Results

Critically wounded persons after Wenchuan and Lushan earthquake were managed according to the “four centralised strategies of care”, namely casualties, experts, resources and patients, which were designed to make the best use of limited resources. The collection of disaster response resources was not the sooner the better. The vulnerability and anti-disaster capacity of quake-hit zone and the degree of matching between critical elements of a response system and its supporting systems should be considered. The training of rescue teams in rural and high-altitude areas should be strengthened. Non-government organisations, the government and the public should join together to deal with the disaster.

Conclusions

In this paper, we evaluate the disaster relief systems in China through a retrospective analysis of medical practice of catastrophic events in recent years. This review suggests that there are a lot of experiences and lessons on how to prepare and respond to disasters in China, especially those in plateau mountain region and those considering emergency responses to catastrophic events. (Hong Kong j.emerg.med. 2015;22:270-280)

Evaluation of the Revised Trauma Score in Predicting Outcomes of Trauma Patients

Introduction

The revised trauma score (RTS) was developed more than 20 years ago. Few studies investigated its usefulness in predicting trauma outcomes. This is especially true for the weighted version of RTS (RTS-w). The aim of this study was to test the predicting power of RTS-w for the trauma outcomes including mortality, admission to intensive care unit (ICU), hospital length of stay and ICU length of stay through a comparison with Injury Severity Score (ISS).

Methods

Descriptive data, variables related to the trauma scores and outcomes were collected. The statistical performance of RTS-w and ISS in predicting the trauma outcomes using receiver operating characteristics (ROC) curves and the area under the curve (AUC) with 95% confidence interval and p value were calculated. The Hosmer-Lemeshow chi-squared statistic was performed to measure its calibration.

Results

A total of 3323 patients were enrolled in the study. RTS-w was significantly better than ISS in predicting mortality of trauma patients (AUC: 0.934 vs.0.880, p<0.0001). However, for the other three outcomes, i.e. admission to ICU, hospital length of stay and intensive care unit length of stay, the performance of RTS-w was inferior to ISS.

Conclusions

The RTS-w is a better predictor of mortality than ISS. But its ability to predict other trauma outcomes is not as good as ISS. More studies are needed to identify the predictive ability of RTS-w for the outcomes other than mortality. Besides, updating the coefficients of the formula may make RTS-w more accurate.

Adjuvant transcatheter arterial chemoembolization for intrahepatic cholangiocarcinoma after curative surgery: retrospective control study

BACKGROUND

Effects of adjuvant transcatheter arterial chemoembolization (TACE) for intrahepatic cholangiocarcinoma (ICC) radical surgery have never been evaluated.

METHODS

A retrospective analysis was conducted on 125 ICC patients who had undergone operations with curative intent in Shanghai Eastern Hepatobiliary Surgery Hospital from July 2002 to December 2003. Of these patients, 53 underwent adjuvant TACE (TACE group) and 72 did not (non-TACE group). Adjuvant TACE was performed one time 1.5-2.0 months after the operation.

RESULTS

Follow-up was performed at a median of 18 months (range 3-96 months). There was no significant recurrence-free survival (RFS) difference between the TACE and non-TACE groups (P = 0.659). The 1-, 3-, and 5-year overall survival (OS) rates were 69.8, 37.7, and 28.3%, respectively, for the TACE group and 54.2, 25.0, and 20.8%, respectively, for the non-TACE group (P = 0.045). Among 54 patients with a recurrence time of ≤ 3 months, the OS rate of the TACE group was better than that of the non-TACE group (P < 0.001). For 59 patients with a recurrence time later than the median RFS, no significant RFS difference was found between the TACE and non-TACE groups (P = 0.681). These results indicate that TACE could not delay recurrence but could prolong the OS of patients with early recurrence.

CONCLUSIONS

Adjuvant TACE after radical surgery was associated with better survival among the ICC patients with early recurrence.

Cloning and RNAi-mediated functional characterization of MaLac2 of the pine sawyer, Monochamus alternatus

Laccase, a member of a group of proteins collectively known as multicopper oxidases, is hypothesized to play an important role in insect cuticle sclerotization by oxidizing catechols in the cuticle to their corresponding quinones, which then catalyze protein cross-linking reactions. Laccase 2 has been proved as the gene required for beetle cuticle tanning through RNA interference (RNAi) experiments on red flour beetle Tribolium castaneum. The pine sawyer beetle, Monochamus alternatus (Coleoptero: Cerambycidae) is the insect serving as a major vector of the pinewood nematode, Bursaphelenchus xylophilus, which is the causative agent for pine wilt disease. The cDNA of MaLac2 was cloned from the insect in this study. The conceptual amino-acid sequence deduced was much conserved with other known insect laccases, particularly with the enzyme of Tribolium castaneum. Injection in hemolymph of pine sawyer larva of dsRNA targeting the laccase 2 mRNA leads to important alterations of the tanning, hardening and sclerotization of the pupal and adult cuticles. Defaults appear in a dose-dependent manner and high loads of dsRNA are lethal. The decrease of the endogenous laccase 2 mRNA affects the procuticle which is thinner and without the characteristic piling up of successive layers. The observations reinforce the role of laccase 2 as an essential phenoloxidase for making cuticle.

The HOX homeodomain proteins block CBP histone acetyltransferase activity

Despite the identification of PBC proteins as cofactors that provide DNA affinity and binding specificity for the HOX homeodomain proteins, HOX proteins do not demonstrate robust activity in transient-transcription assays and few authentic downstream targets have been identified for these putative transcription factors. During a search for additional cofactors, we established that each of the 14 HOX proteins tested, from 11 separate paralog groups, binds to CBP or p300. All six isolated homeodomain fragments tested bind to CBP, suggesting that the homeodomain is a common site of interaction. Surprisingly, CBP-p300 does not form DNA binding complexes with the HOX proteins but instead prevents their binding to DNA. The HOX proteins are not substrates for CBP histone acetyltransferase (HAT) but instead inhibit the activity of CBP in both in vitro and in vivo systems. These mutually inhibitory interactions are reflected by the inability of CBP to potentiate the low levels of gene activation induced by HOX proteins in a range of reporter assays. We propose two models for HOX protein function: (i) HOX proteins may function without CBP HAT to regulate transcription as cooperative DNA binding molecules with PBX, MEIS, or other cofactors, and (ii) the HOX proteins may inhibit CBP HAT activity and thus function as repressors of gene transcription.

Functional cloning and characterization of a novel nonhomeodomain protein that inhibits the binding of PBX1-HOX complexes to DNA

PBX1 is a homeodomain protein that functions in complexes with other homeodomain-containing proteins to regulate gene expression during developmental and/or differentiation processes. A yeast two-hybrid screen of a fetal liver-hematopoietic cDNA library using PBX1a as bait led to the discovery of a novel non-homeodomain-containing protein that interacts with PBX1 as well as PBX2 and PBX3. RNA analysis revealed it to be expressed in CD34(+) hematopoietic cell populations enriched in primitive progenitors, as is PBX1; search of the expressed sequence tag data base indicated that it is also expressed in other early embryonic as well as adult tissues. The full-length cDNA encodes a 731-amino acid protein that has no significant homology to known proteins. This protein that we have termed hematopoietic PBX-interacting protein (HPIP) is mainly localized in the cytosol and in small amounts in the nucleus. The region of PBX that interacts with HPIP includes both the homeodomain and immediate N-terminal flanking sequences. Strikingly, electrophoretic mobility shift assays revealed that HPIP inhibits the ability of PBX-HOX heterodimers to bind to target sequences. Moreover, HPIP strongly inhibits the transactivation activity of E2A-PBX. Together these findings suggest that HPIP is a new regulator of PBX function.

Changes in HOXB6 homeodomain protein structure and localization during human epidermal development and differentiation

HOX homeodomain proteins are master developmental regulators, which are now thought to function as transcription factors by forming cooperative DNA binding complexes with PBX or other protein partners. Although PBX proteins exhibit regulated subcellular localization and function in the nucleus in other tissues, little data exists on HOX and PBX protein localization during skin development. We now show that the HOXB6 protein is expressed in the suprabasal layer of the early developing epidermis and throughout the upper layers of late fetal and adult human skin. HOXB6 signal is cytoplasmic throughout fetal epidermal development, but substantially nuclear in normal adult skin. HOXB6 protein is also partially nuclear in hyperproliferative skin conditions, but appears to be cytoplasmic in basal and squamous cell carcinomas. Although all three PBX genes are expressed in fetal epidermis, none of the three PBX proteins exhibit nuclear co-localization with HOXB6 in either fetal or adult epidermis. RNA and protein data suggest that a truncated HOXB6 protein, lacking the homeodomain, is expressed in undifferentiated keratinocytes and that the full-length protein is induced by differentiation. GFP-fusion proteins were used to demonstrate that the full-length HOXB6 protein is localized to the nucleus while the truncated protein is largely cytoplasmic. Taken together, these data suggest that during epidermal development the truncated HOXB6 isoform may function by a mechanism other than as DNA binding protein, and that most of the nuclear, homeodomain-containing HOXB6 protein does not utilize PBX proteins as DNA binding partners in the skin. Published 2000 Wiley-Liss, Inc.

HOXA9 forms triple complexes with PBX2 and MEIS1 in myeloid cells

Aberrant activation of the HOX, MEIS, and PBX homeodomain protein families is associated with leukemias, and retrovirally driven coexpression of HOXA9 and MEIS1 is sufficient to induce myeloid leukemia in mice. Previous studies have demonstrated that HOX-9 and HOX-10 paralog proteins are unique among HOX homeodomain proteins in their capacity to form in vitro cooperative DNA binding complexes with either the PBX or MEIS protein. Furthermore, PBX and MEIS proteins have been shown to form in vivo heterodimeric DNA binding complexes with each other. We now show that in vitro DNA site selection for MEIS1 in the presence of HOXA9 and PBX yields a consensus PBX-HOXA9 site. MEIS1 enhances in vitro HOXA9-PBX protein complex formation in the absence of DNA and forms a trimeric electrophoretic mobility shift assay (EMSA) complex with these proteins on an oligonucleotide containing a PBX-HOXA9 site. Myeloid cell nuclear extracts produce EMSA complexes which appear to contain HOXA9, PBX2, and MEIS1, while immunoprecipitation of HOXA9 from these extracts results in coprecipitation of PBX2 and MEIS1. In myeloid cells, HOXA9, MEIS1, and PBX2 are all strongly expressed in the nucleus, where a portion of their signals are colocalized within nuclear speckles. However, cotransfection of HOXA9 and PBX2 with or without MEIS1 minimally influences transcription of a reporter gene containing multiple PBX-HOXA9 binding sites. Taken together, these data suggest that in myeloid leukemia cells MEIS1 forms trimeric complexes with PBX and HOXA9, which in turn can bind to consensus PBX-HOXA9 DNA targets.

AbdB-like Hox proteins stabilize DNA binding by the Meis1 homeodomain proteins

Recent studies show that Hox homeodomain proteins from paralog groups 1 to 10 gain DNA binding specificity and affinity through cooperative binding with the divergent homeodomain protein Pbx1. However, the AbdB-like Hox proteins from paralogs 11, 12, and 13 do not interact with Pbx1a, raising the possibility of different protein partners. The Meis1 homeobox gene has 44% identity to Pbx within the homeodomain and was identified as a common site of viral integration in myeloid leukemias arising in BXH-2 mice. These integrations result in constitutive activation of Meis1. Furthermore, the Hoxa-9 gene is frequently activated by viral integration in the same BXH-2 leukemias, suggesting a biological synergy between these two distinct classes of homeodomain proteins in causing malignant transformation. We now show that the Hoxa-9 protein physically interacts with Meis1 proteins by forming heterodimeric binding complexes on a DNA target containing a Meis1 site (TGACAG) and an AbdB-like Hox site (TTTTACGAC). Hox proteins from the other AbdB-like paralogs, Hoxa-10, Hoxa-11, Hoxd-12, and Hoxb-13, also form DNA binding complexes with Meis1b, while Hox proteins from other paralogs do not appear to interact with Meis1 proteins. DNA binding complexes formed by Meis1 with Hox proteins dissociate much more slowly than DNA complexes with Meis1 alone, suggesting that Hox proteins stabilize the interactions of Meis1 proteins with their DNA targets.

The Abd-B-like Hox homeodomain proteins can be subdivided by the ability to form complexes with Pbx1a on a novel DNA target

Previous studies showed that the Hox homeodomain proteins from paralog groups 1-8 display cooperative DNA binding with the non-Hox homeodomain protein Pbx, mediated by a canonical YPWM. Although the Abd-B-like Hox proteins in paralogs 9-13 lack this sequence, Hoxb-9 and Hoxa-10 were reported to bind with Pbx1a to DNA. We show that these interactions require a tryptophan 6 amino acids N-terminal to the homeodomain. Binding site selection for Hoxb-9 with Pbx1a yielded ATGATTTACGAC, containing a novel TTAC Hox-binding site adjacent to a Pbx site. In the presence of Pbx1a, Hoxb-9 and Hoxa-10 bound to targets containing either TTAC or TTAT. These data extend previous findings that interactions with Pbx define a Hox protein binding code for different DNA sequences across paralog groups 1 through 10. Members of the 11, 12, and 13 paralogs do not cooperatively bind DNA with Pbx1a, despite the presence of tryptophan residues N-terminal to the homeodomain in Hoxd-12 and Hoxd-13. Hoxa-11, Hoxd-12, or Hoxd-13, in the presence of Pbx1a, selected a TTAC Hox site but lacking a Pbx1a site. These data suggest that Abd-B-like Hox proteins bind to a novel TTAC site and can be divided by their cooperative binding to DNA with Pbx1a.

[Can Doppler echocardiography help to avoid cardiac catheterization in the surgical decision-making in isolated left heart valve diseases?]

The aim of this study was to assess the value of non-invasive investigation based on clinical evaluation and Doppler echography in deciding the operative indications of patients with isolated left heart valvular lesions compared. Three hundred and thirty five patients were included in a prospective study: 78 had MR, 57 had AR, 150 had AS and 50 had MS. All underwent clinical. Doppler echography and catheter studies. The therapeutic decision was taken blind by two groups of 2 cardiologists. Group I took its decision based on clinical findings and results of Doppler echography whilst Group II took its decision on the clinical and catheter data. For each patient, one of the following three choices was proposed: 1) medical treatment: 2) surgery or valvuloplasty with balloon catheter; 3) request for further information. In addition, in group I, the need for coronary angiography was left to the appreciation of two cardiologists. The quantification of the valvular disease was concordant for groups I and II in 93, 97, 98.5 and 100% for MR, AR, AS and MS respectively. These percentages were respectively 97, 95, 92 and 100% for assessment of left ventricular function. The theoretical management decision was concordant between the two groups for 97% of MR, 94.7% of AR, 95.3% of AS and 94% of MS. Complementary information requiring invasive studies was required by group I in 3.9% of cases. A discordant opinion was obtained in 0.6% of cases (2 cases of AS). Coronary angiography was requested by the cardiologists of Group I in 34% of patients, identifying all patients who underwent coronary bypass surgery. These results show that cardiac catheterisation is no longer an essential diagnostic procedure for discussing the indications of valvular surgery in the majority of patients with isolated left heart lesions.

Pbx modulation of Hox homeodomain amino-terminal arms establishes different DNA-binding specificities across the Hox locus

Pbx cofactors are implicated to play important roles in modulating the DNA-binding properties of heterologous homeodomain proteins, including class I Hox proteins. To assess how Pbx proteins influence Hox DNA-binding specificity, we used a binding-site selection approach to determine high-affinity target sites recognized by various Pbx-Hox homeoprotein complexes. Pbx-Hox heterodimers preferred to bind a bipartite sequence 5'-ATGATTNATNN-3' consisting of two adjacent half sites in which the Pbx component of the heterodimer contacted the 5' half (ATGAT) and the Hox component contacted the more variable 3' half (TNATNN). Binding sites matching the consensus were also obtained for Pbx1 complexed with HoxA10, which lacks a hexapeptide but requires a conserved tryptophan-containing motif for cooperativity with Pbx. Interactions with Pbx were found to play an essential role in modulating Hox homeodomain amino-terminal arm contact with DNA in the core of the Hox half site such that heterodimers of different compositions could distinguish single nucleotide alterations in the Hox half site both in vitro and in cellular assays measuring transactivation. When complexed with Pbx, Hox proteins B1 through B9 and A10 showed stepwise differences in their preferences for nucleotides in the Hox half site core (TTAT to TGAT, 5' to 3') that correlated with the locations of their respective genes in the Hox cluster. These observations demonstrate previously undetected DNA-binding specificity for the amino-terminal arm of the Hox homeodomain and suggest that different binding activities of Pbx-Hox complexes are at least part of the position-specific activities of the Hox genes.

Clinical significance of intracavitary spontaneous echo contrast in patients with dilated cardiomyopathy

To assess the occurrence rate and major determinants of spontaneous echo contrast and to examine its impact on thromboembolic events and mortality in patients with dilated cardiomyopathy, 86 hospitalized patients (73 men and 13 women, mean age 63 +/- 11 years) with dilated cardiomyopathy who underwent transthoracic and transesophageal echocardiographic examinations were followed up for a mean of 20 +/- 13 months. Spontaneous echo contrast was observed in 36 patients (42%) and was detected only with the transesophageal approach. It was seen in the left atrium in 33 patients, in both right and left atria in 1 patient, in both left atrium and left ventricle in 1 patient, and in the descending aorta in 1 patient. Spontaneous echo contrast was more frequent in the presence of atrial fibrillation (p < 0.05), left atrial enlargement (p < 0.02) and severely depressed left ventricular function (p < 0.01), but was less common in patients with moderate to severe mitral regurgitation (p < 0.05). This imaging phenomenon was the only significant independent predictor of intracardiac thrombus formation and previous and subsequent thromboembolic events. During follow-up, there were 26 deaths, and survival in patients with spontaneous echo contrast was significantly lower than in those without it (p < 0.02). A spontaneous echo contrast is commonly detected with transesophageal echocardiography in patients with dilated cardiomyopathy especially in the presence of atrial fibrillation, left atrial enlargement and severe left ventricular dysfunction. This imaging phenomenon represents an important marker for thromboembolic risk and may influence the treatment and clinical outcome of these patients.

Hox homeodomain proteins exhibit selective complex stabilities with Pbx and DNA

Eight of the nine homeobox genes of the Hoxb locus encode proteins which contain a conserved hexapeptide motif upstream from the homeodomain. All eight proteins (Hoxb-1-Hoxb-8) bind to a target oligonucleotide in the presence of Pbx1a under conditions where minimal or no binding is detected for the Hox or Pbx1a proteins alone. The stabilities of the Hox-Pbx1a-DNA complexes vary >100-fold, with the proteins from the middle of the locus (Hoxb-5 and Hoxb-6) forming very stable complexes, while Hoxb-4, Hoxb-7 and Hoxb-8 form complexes of intermediate stability and proteins at the 3'-side of the locus (Hoxb-1-Hoxb-3) form complexes which are very unstable. Although Hox-b proteins containing longer linker sequences between the hexapeptide and homeodomains formed unstable complexes, shortening the linker did not confer complex stability. Homeodomain swapping experiments revealed that this motif does not independently determine complex stability. Naturally occurring variations within the hexapeptides of specific Hox proteins also do not explain complex stability differences. However, two core amino acids (tryptophan and methionine) which are absolutely conserved within the hexapeptide domains appear to be required for complex formation. Removal of N- and C-terminal flanking regions did not influence complex stability and the members of paralog group 4 (Hoxa-4, b-4, c-4 and d-4), which share highly conserved hexapeptides, linkers and homeodomains but different flanking regions, form complexes of similar stability. These data suggest that the structural features of Hox proteins which determine Hox-Pbx1a-DNA complex stability reside within the precise structural relationships between the homeodomain, hexapeptide and linker regions.

Comparative value of Doppler echocardiography and cardiac catheterization for management decision-making in patients with left-sided valvular regurgitation

OBJECTIVE

The purpose of this study was to examine the value of non-invasive clinical and Doppler echocardiographic findings, compared to cardiac catheterization, in management decision-making for patients with left-sided valvular regurgitation.

METHODS

One hundred and thirty-five consecutive patients with left-sided valvular regurgitation who underwent cardiac catheterization and detailed Doppler echocardiography were prospectively studied. Two independent groups of experienced cardiologists, given clinical information combined with either Doppler echocardiographic or cardiac catheterization data, decided to operate, not to operate, or remained uncertain.

RESULTS

In 63 (81%) of 78 patients with mitral regurgitation, there was agreement on the decision for valve surgery or medical treatment between Doppler echocardiography and cardiac catheterization. Valve repair was performed in 22 patients, which agreed with the echocardiographic decision. In the remaining 15 patients, although the severity and type of mitral valve lesions and left ventricular functional status were confirmed by Doppler echocardiography, the clinical decision was uncertain; additional information concerning coronary anatomy (13 patients) and pulmonary artery pressure (one patient) or both (one patient) was required. In 47 of 57 patients (82%) with aortic regurgitation, there was agreement on their management as a result of Doppler echocardiography and cardiac catheterization findings. In 10 patients, the clinical decision reached with the help of Doppler echocardiography alone was uncertain and coronary (seven patients), left ventricular (two patients) angiography or aortography (one patient) were requested. Overall, there were no conflicting clinical decisions made by the two methods in patients with either mitral or aortic regurgitation.

CONCLUSIONS

In every patient in whom it was considered that a decision could be reached by echocardiography alone (more than 80% of patients) there was 100% agreement from the cardiac catheterization assessment group on the management decision. Therefore, in patients with significant mitral or aortic regurgitation where echocardiographic data is adequate, cardiac catheterization can be safely omitted from the investigative process for surgery. Where echocardiographic indices are conflicting, or significant coronary artery disease is suspected, cardiac catheterization is required.

[Does mitral insufficiency prevent spontaneous contrast phenomenon and formation of thrombi in the left atrium?]

The aim of this study was to assess the influence of mitral regurgitation on the prevalence of left atrial spontaneous echo contrast and thrombosis in 2,180 consecutive patients undergoing transthoracic and transoesophageal echocardiography. Two groups of patients were defined according to the absence (group I) or presence (group II) of grades 3 or 4 mitral regurgitation quantified by transoesophageal echocardiography. Group II was associated with a statistically significant lower frequency of spontaneous echo contrast (0.6 vs 11.2%; p < 0.0001), left atrial thrombosis (0.6 vs 4.2%; p < 0.03), ischaemic cerebrovascular accidents (1.2 vs 21%; p < 0.0001), transient ischaemic attacks (0 vs 12%; p < 0.0001) and systemic embolism (0 vs 4.6%; p < 0.01). Conversely, the prevalence of atrial fibrillation was higher in group II (28 vs 19%; p < 0.01) and there were more patients with left atrial dimensions > or = 5.5 cm (16 vs 6.7%; p < 0.0001). When mitral stenosis and valve prosthesis were excluded, there were no cases of spontaneous echo contrast (8.3 vs 0%; p < 0.001) or left atrial thrombosis (2.9 vs 0%; p < 0.05) in the group with grades 3 or 4 mitral regurgitation. The phenomenon of left atrial spontaneous echo contrast and/or thrombosis is rare in patients with grade 3 or 4 in native mitral valve regurgitation and explains the low incidence of systemic embolism in these cases.

Pbx proteins display hexapeptide-dependent cooperative DNA binding with a subset of Hox proteins

The human proto-oncogene PBX1 codes for a homolog of Drosophila extradenticle, a divergent homeo domain protein that modulates the developmental and DNA-binding specificity of select HOM proteins. We demonstrate that wild-type Pbx proteins and chimeric E2a-Pbx1 oncoproteins cooperatively bind a consensus DNA probe with HoxB4, B6, and B7 of the Antennapedia class of Hox/HOM proteins. Specificity of Hox-Pbx interactions was suggested by the inability of Pbx proteins to cooperatively bind the synthetic DNA target with HoxA10 or Drosophila even-skipped. Site-directed mutagenesis showed that the hexapeptide motif (IYPWMK) upstream of the Hox homeo domain was essential for HoxB6 and B7 to cooperatively bind DNA with Pbx proteins. Engraftment of the HoxB7 hexapeptide onto HoxA10 endowed it with robust cooperative properties, demonstrating a functional role for the highly conserved hexapeptide element as one of the molecular determinants delimiting Hox-Pbx cooperativity. The Pbx homeo domain was necessary but not sufficient for cooperativity, which required conserved amino acids carboxy-terminal of the homeo domain. These findings demonstrate that interactions between Hox and Pbx proteins modulate their DNA-binding properties, suggesting that Pbx and Hox proteins act in parallel as heterotypic complexes to regulate expression of specific subordinate genes.

Tyrosine phosphorylation is required for up-regulation of the HOX-11 (TCL-3) homeobox proto-oncogene in T cells

HOX-11 (TCL-3) is a homeobox proto-oncogene isolated from the breakpoint region of the t(10;14) chromosomal translocation associated with pediatric T-cell acute leukemia. To better understand the transcriptional regulation of the HOX-11 gene in response to extracellular signals, the levels of HOX-11 RNA were examined in normal and leukemic human T cells upon phytohemagglutinin and hematopoietic growth factor stimulation. While individual hematopoietic growth factors tested did not show any effect on HOX-11 gene expression, a drastic increase in HOX-11 RNA was observed under the induction of phytohemagglutinin. In the presence of cycloheximide, a protein synthesis inhibitor, phytohemagglutinin-induced HOX-11 up-regulation was suppressed, indicating that HOX-11 acts as a delayed early response gene which requires protein synthesis. The HOX-11 gene expression was also suppressed by the tyrosine kinase inhibitors tryphostin and lavendustin A. Our data therefore suggest that the delayed early response of HOX-11 up-regulation in T cells requires a tyrosine phosphorylation signal.

[Assessment of coronary flow reserve in patients with angina pectoris]

Coronary flow reserve was assessed by using a computer-assisted method in 26 normal controls and 45 patients with significant coronary artery stenosis ( > or = 50% luminal narrowing) and 16 patients with syndrome X. After intracoronary administration of papaverine, the diameter, cross sectional area, blood velocity, flow volume and reserve capacity of both left anterior descending (LAD) and right coronary arteries (RCA) were lower in patients with significant coronary stenosis than in controls. Despite similar changes in the diameter and cross sectional area, the velocity, flow volume and reserve capacity of these two vessels were also lower in patients with syndrome X than in controls. We conclude that coronary flow reserve is reduced in patients with coronary artery stenosis or syndrome X due to different levels of coronary artery abnormalities.

Mitral to aortic velocity-time integral ratio. A non-geometric pulsed-Doppler regurgitant index in isolated pure mitral regurgitation

To determine the clinical value of a simple and non-geometric pulsed Doppler regurgitant index, namely the mitral to aortic velocity-time integral (VTI) ratio in the semiquantitative assessment of severity of isolated pure mitral regurgitation (MR), 109 patients with isolated pure MR and sinus rhythm prospectively underwent Doppler echocardiography within 48 h of cardiac catheterization. The eccentricity of regurgitant jets was assessed by Doppler colour flow imaging and the mitral and aortic VTI and its ratio were derived from the pulsed Doppler method. Angiographic grade of MR was evaluated in all patients with MR, but haemodynamic regurgitant fraction was determined in only 91 patients. Fifty patients in sinus rhythm and without valvular disease served as controls. In the control group, the mitral VTI (16.2 +/- 2.5 cm) was lower than the aortic VTI (20.6 +/- 2.8 cm) (P < 0.001), resulting in a mitral to aortic VTI ratio of 0.79 +/- 0.08. In patients with MR, the mitral VTI was significantly greater than the aortic VTI (23.1 +/- 6.8 vs 16.9 +/- 4.7 cm, P < 0.001). There was a close relationship between the mitral to aortic VTI ratio and the angiographic grading of MR (n = 109, r = 0.74, P < 0.001). A ratio > or = 1.3 classified patients with severe MR (grade III or IV) with a sensitivity of 87%, a specificity of 91%, and positive and negative predictive values of 93% and 84%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitation of aortic valve area in aortic stenosis with multiplane transesophageal echocardiography: comparison with monoplane transesophageal approach

The accuracy and reliability of two-dimensional monoplane and multiplane transesophageal echocardiography (TEE) in the quantitation of aortic valve area were compared in 54 patients with aortic stenosis. Fifty patients had aortic valve area calculated by the continuity equation and transthoracic Doppler echocardiography (TTE); 25 underwent cardiac catheterization. Two-dimensional echocardiograms adequate for quantitation of aortic valve area were obtained in 21 (39%) patients with monoplane TEE and in 51 (94%) with multiplane TEE. The mean aortic valve area determined by both TEE methods did not differ significantly from that derived from TTE and catheterization. The mean difference of aortic valve area measurements between monoplane TEE and TTE was -0.045 +/- 0.11 cm2; that between multiplane TEE and TTE was 0.001 +/- 0.11 cm2. Multiplane TEE provided a better correlation of aortic valve area measurements with either TTE (y = 0.97 x + 0.03; r = 0.96; SEE = 0.11 cm2) or catheterization (y = 0.84 x + 0.11; r = 0.90; SEE = 0.12 cm2) than the monoplane TEE (y = 0.88 x + 0.13; r = 0.83; SEE = 0.15 cm2 and y = 0.41 x + 0.42; r = 0.81; SEE = 0.15 cm2). Severe aortic stenosis with valve orifice area of < or = 0.75 cm2 during TTE examination was found by multiplane TEE with a sensitivity of 96% and a specificity of 96%. Thus aortic valve area can be directly and reliably measured by two-dimensional multiplane TEE in majority of patients with aortic stenosis.

Noninvasive prediction of coronary artery disease by transesophageal echocardiographic detection of thoracic aortic plaque in valvular heart disease

Clinical and angiographic features and transesophageal echocardiographic (TEE) findings were retrospectively analyzed in 105 consecutive patients with valvular heart disease to assess the value of TEE detection of thoracic aortic plaque for predicting coronary artery disease. In 19 patients with significant coronary artery stenosis (> or = 70% narrowing of the luminal diameter in the left anterior descending, left circumflex, or right coronary arteries, or > or = 50% stenosis of the left main coronary artery), 18 had thoracic aortic plaque on TEE study. In contrast, aortic plaque existed in only 10 of the remaining 86 patients with normal coronary arteries or mildly atherosclerotic coronary lesions. The presence of aortic plaque on TEE study had a sensitivity of 95% and a specificity study had a sensitivity of 95% and a specificity of 88% for significant coronary stenosis at angiography. The positive and negative predictive values were 64% and 99%, respectively. There was a close relation between the degree of aortic intimal changes and the severity of coronary artery disease (r = 0.65; p < 0.001). Multivariate stepwise regression analysis of patient age, sex, risk factors of cardiovascular disease, angina, and TEE findings revealed that atherosclerotic aortic plaque was the most significant independent predictor of coronary artery disease. This study indicates that TEE detection of atherosclerotic plaque in the thoracic aorta is useful in the noninvasive prediction of the presence and severity of coronary artery disease in patients with valvular heart disease.

[Contribution of transesophageal and transthoracic echography in the evaluation of the mechanism and quantification of regurgitation in mitral and aortic bioprosthetic valves]

The respective values of transoesophageal (TOE) and transthoracic echocardiography (TTE) in the evaluation of the mechanism and the quantification of pathological regurgitation of bioprosthetic heart valves were analysed in 23 patients (14 mitral, 9 aortic; duration of implantation 108 +/- 43.2 months). Surgical or pathological correlations were available in all cases and catheter data in 18 of the 23 patients. With regards to mitral bioprostheses, the TOE evaluations of the mechanism and site of regurgitation corresponded in all cases with the operative or pathological findings and quantification of mitral regurgitation concorded with angiography. There was an underestimation of the severity of mitral regurgitation in 30% of cases by TTE compared with angiography; prolapse was diagnosed in 7 of the 10 cases with cusp tears. It was not possible to accurately determine the intra or perivalvular site of regurgitation by TEE. With regards to aortic bioprostheses, TOE and TTE were equally useful in determining the mechanism of regurgitation, showing cusp prolapse in 6 of the 9 cases with cusp tears. However, TTE quantified regurgitation accurately in all cases with respect to angiography, whereas TOE was only contributive in 50% of cases. These results show that single plane TOE is superior to TTE in the quantification and determination of the mechanism of regurgitation in mitral bioprostheses, but that TTE remains better for the quantification of regurgitation of aortic bioprostheses.

Prognostic importance of left ventricular diastolic filling velocity profiles in dilated cardiomyopathy

To determine the prognostic importance of pulsed Doppler-derived left ventricular diastolic filling velocity profiles and the relationship between Doppler variables and clinical functional status, the follow-up outcome of 58 patients with dilated cardiomyopathy and symptoms of left ventricular dysfunction was analysed. During a mean follow-up period of 31.2 +/- 12.8 months, 23 died of either progressive pump failure or sudden death. Peak early filling velocity (E) was higher and late atrial filling velocity (A) lower in nonsurvivors than in survivors. The E/A ratio was higher and the deceleration time (DT) of early diastole shorter in nonsurvivors. The mortality was significantly higher in patients with an E/A ratio > 2 or a DT < 150 ms than in those without. Repeated Doppler echocardiographic examinations in 31 of 35 survivors after intense treatment showed decreased E, increased A, reduced E/A ratio and prolonged DT in 18 patients with clinical functional improvement, whereas these measurements were unaltered in the remaining 13 patients whose functional status was unchanged or deteriorated. This study suggests that pulsed Doppler-derived left ventricular diastolic filling variables may be important predictors of outcome in dilated cardiomyopathy and provide useful measures in observing the effects of therapy during long-term follow-up of the patients.

Prognostic significance of Doppler-derived left ventricular diastolic filling variables in dilated cardiomyopathy

To determine the prognostic significance of pulsed wave Doppler-derived left ventricular diastolic filling velocity profiles and the relationship between Doppler variables and clinical functional status, the follow-up outcomes of 62 consecutive patients with dilated cardiomyopathy and symptoms of left ventricular dysfunction were analyzed. All patients had echocardiographic left ventricular end-diastolic dimension > or = 6.0 cm, fractional shortening < 25%, increased E pointseptal separation, and diffuse hypokinesia or akinesia. During a mean follow-up period of 30.5 +/- 13.9 months, 27 patients experienced cardiac events: 23 died of either progressive pump failure or an episode of sudden death and four required cardiac transplantation because of refractory heart failure. Peak early filling velocity (78 +/- 23 cm/sec vs 65 +/- 25 cm/sec; p < 0.03) was higher and late atrial filing velocity (34 +/- 13 cm/sec vs 55 +/- 19 cm/sec; p < 0.001) was lower in patients with cardiac events than in cardiac event-free survivors. The ratio of early to late transmitral filling velocities was higher (2.6 +/- 1.2 vs 1.5 +/- 1.3; p < 0.001), and the deceleration time of early diastole was shorter (133 +/- 48 msec vs 175 +/- 71 msec; p < 0.001) in patients with cardiac events. The cardiac event rate was significantly higher in patients with an early to late filling velocity ratio greater than 2 (77% vs 19%; p < 0.001) or a deceleration time less than 150 msec (58% vs 23%; p < 0.05) than in those without. Stepwise multivariate regression analysis revealed that the pattern of transmitral early to late filling velocity ratio was the only significant independent Doppler echocardiographic predictor of outcome for these patients. Repeat Doppler echocardiographic examinations, which were performed in 31 survivors after intensive treatment (mean, 38.6 +/- 6.5 months), showed that early filling velocity was decreased (55 +/- 20 cm/sec vs 75 +/- 25 cm/sec; p < 0.02), late atrial filling velocity was increased (74 +/- 27 cm/sec vs 57 +/- 21 cm/sec; p < 0.01), early to late filling velocity ratio was reduced (0.8 +/- 0.3 vs 1.7 +/- 1.3; p < 0.001), and deceleration time was prolonged (227 +/- 60 msec vs 167 +/- 82 msec; p < 0.01) in 18 patients with clinical functional improvement, whereas these measurements were unaltered in the remaining 13 patients whose functional status was unchanged or had deteriorated.(ABSTRACT TRUNCATED AT 400 WORDS)

Assessment of severity of mitral regurgitation by measuring regurgitant jet width at its origin with transesophageal Doppler color flow imaging

BACKGROUND

The ability of transesophageal color Doppler echocardiography to provide high-resolution images of both cardiac structure and blood flow in real time is advantageous for many clinical purposes. This study was performed to determine the utility of the regurgitant jet width at its origin measured by transesophageal Doppler color flow imaging in the assessment of severity of mitral regurgitation.

METHODS AND RESULTS

Sixty-three consecutive patients with mitral regurgitation underwent transesophageal color Doppler examination, and the diameter of regurgitant jet at its origin was measured. Both right and left cardiac catheterizations were performed within 24 hours of Doppler studies, and angiographic grading of mitral regurgitation and regurgitant stroke volume were evaluated. There was a close relation between the jet diameter at its origin measured by transesophageal Doppler color flow imaging and the angiographic grade of mitral regurgitation (r = 0.86, p less than 0.001). A jet diameter of 5.5 mm or more identified severe mitral regurgitation (grade III or IV) with a sensitivity of 92%, specificity of 92%, and positive and negative predictive values of 88% and 95%, respectively. In 31 patients with isolated mitral regurgitation, the jet diameter correlated well with the regurgitant stroke volume determined by a combined hemodynamic-angiographic method (r = 0.85, p less than 0.001). A jet diameter of 5.5 mm or more identified a regurgitant stroke volume of 60 ml or more with a sensitivity of 88%, specificity of 93%, and positive and negative predictive values of 94% and 87%, respectively.

CONCLUSIONS

The regurgitant jet width at its origin measured by transesophageal Doppler color flow imaging provides a simple and useful method of measuring the severity of mitral regurgitation, and it may allow differentiation between mild and severe mitral regurgitation.

Modulation of homeobox gene expression alters the phenotype of human hematopoietic cell lines

We have previously reported that certain genes of the HOX2 cluster of homeobox genes on human chromosome 17 are specifically expressed in human leukemic cell lines with erythroid potential, suggesting that these genes are involved in hematopoietic differentiation. We now show that the expression of the HOX 2.2 gene decreases during erythropoietin-induced differentiation of the erythroid cell line MB02. In order to study the role of the HOX 2.2 homeobox gene in hematopoiesis, vectors producing sense or antisense transcripts were introduced into K562 and HEL cells, pluripotent lines with erythroid and myeloid features. Overexpression of HOX 2.2 is associated with loss of erythroid features in both lines and an increase in certain myelomonocytic markers in K562 cells. Expression of antisense HOX 2.2 is associated with an increase in erythroid features in HEL cells and a mild decrease in myeloid characteristics in K562 cells. Overexpression of the adjacent HOX 2.1 gene in K562 cells does not produce similar phenotype changes. These data demonstrate that modulation of a specific HOX 2 homeobox gene can change the phenotype of somatic cells and suggest that certain HOX 2 genes play a role in blood cell differentiation.

Left ventricular aneurysm and prognosis in patients with first acute transmural anterior myocardial infarction and isolated left anterior descending artery disease

To determine the clinical and angiographic factors responsible for left ventricular aneurysm formation and the prognosis of patients with aneurysm, 79 patients with a first acute transmural anterior myocardial infarction and angiographically documented isolated left anterior descending artery disease were retrospectively evaluated. Presence of large infarct size and left ventricular volumes, reduced left ventricular function, and evidence of clinical functional impairment were more common in patients with aneurysm (n = 31) than in those without (n = 48). Patients with aneurysm often had total occlusion of the proximal left anterior descending artery without collateral vessels on angiography. During a mean follow-up of 53 months, 10 patients with and three without aneurysm died (P less than 0.01). Compared to survivors with or without aneurysm, the nonsurvivors were older, had significantly larger infarct size and left ventricular volumes and poor systolic function. The incidence of total occlusion of the left anterior descending artery without collaterals was higher in nonsurvivors. In patients with aneurysm, stepwise multivariate analysis revealed that left ventricular ejection fraction and the status of left anterior descending artery obstruction and collaterals were independent predictors of mortality. The study indicates that in patients with a first acute transmural anterior myocardial infarction and isolated anterior descending artery disease, left ventricular aneurysm often results from a large infarct caused by total occlusion of the proximal left anterior descending artery without collateral supply to the infarct region. The reduced survival rate for patients with aneurysm is primarily related to severe global left ventricular dysfunction which may be determined by assessing the residual flow to the infarct region.

Non-invasive measurement of the regurgitant fraction by pulsed Doppler echocardiography in isolated pure mitral regurgitation

OBJECTIVE

To assess the usefulness of pulsed Doppler echocardiography as a method of measuring the regurgitant fraction in patients with mitral regurgitation.

PATIENTS AND METHODS

Twenty controls and 27 patients with isolated mitral regurgitation underwent Doppler studies. In the patients the study was performed within 48 hours of cardiac catheterisation. Aortic outflow was measured in the centre of the aortic annulus, and mitral inflow was derived from the flow velocity at the tip of the leaflets and the area of the elliptical mitral opening. The regurgitant fraction was calculated as the difference between the two flows divided by the mtiral inflow.

RESULTS

In the 20 controls the two flows were almost identical (mitral inflow, 4.44 (SD 0.88) l/min; aortic outflow, 4.58 (SD 0.84) l/min), with a mean regurgitant fraction of 4.2 (SD 8.4)%. In patients with mitral regurgitation, the mitral inflow was significantly higher than the aortic outflow (8.8 (3.6) v 4.3 (1.1) l/min). In most patients the Doppler-derived regurgitant fraction (45.8 (19.2)%) accorded closely with the regurgitant fraction (41.3 (SD 17.8)%) determined by the haemodynamic technique.

CONCLUSION

Pulsed Doppler echocardiography, with an instantaneous velocity-valve area method for calculating mitral inflow, reliably measured the severity of regurgitation in patients with mitral regurgitation.

The tcl-3 proto-oncogene altered by chromosomal translocation in T-cell leukemia codes for a homeobox protein

The t(10;14)(q24;q11) chromosomal translocation found in malignant cells of 5-10% of patients with T-cell acute lymphoblastic leukemia (T-ALL) involves the T-cell receptor delta chain gene on chromosome 14 and a breakpoint cluster region on chromosome 10. The candidate proto-oncogene tcl-3, thought to be involved in the pathogenesis of t(10;14) T-ALL, was cloned and found to be elevated in expression in leukemic cells harboring the t(10;14) translocation. Sequence analysis revealed that tcl-3 is a new homeobox-containing gene. Comparison of the tcl-3 cDNA and its 5' genomic sequences with DNA sequences from the t(10;14) translocation breakpoints showed that this gene is structurally altered in four patients with t(10;14)(q24;q11) T-ALL. These findings suggest that homeobox-containing genes that normally act as transcription factors may contribute to T-cell leukemogenesis when abnormally expressed.

Relationship between electrocardiographic patterns and angiographic features in isolated left circumflex coronary artery disease

The relation of electrocardiographic (ECG) patterns to clinical and angiographic features was assessed in 89 patients with isolated left circumflex coronary artery (LCx) disease (46 with and 43 without myocardial infarction). ECG abnormalities were present in 75 patients; there were isolated Q waves in 20, an abnormal R wave in lead V1 with or without inferior and/or lateral Q waves in 21, and isolated ST-T wave changes in 34 cases. Inferior abnormalities on the electrocardiogram were similar in patients with proximal or distal stenoses of the LCx, but an abnormal R wave in lead V1 correlated with proximal LCx stenosis (p less than 0.01). Lateral abnormalities were more common in stenoses of the obtuse marginal branch and proximal LCx than in distal stenosis (all p less than 0.01). Compared with patients without myocardial infarction with or without ST-T-wave changes and those with infarction without an abnormal R wave in lead V1, patients with LCx-related infarction and an abnormal R wave in lead V1 associated with inferior and/or lateral Q waves had larger left ventricular end-diastolic and end-systolic volumes, lower ejection fraction, higher incidence of total occlusion of proximal LCx without collateral vessels, and more cardiac events during follow-up. This study suggests that an abnormal R wave in lead V1 associated with lateral abnormalities on the standard electrocardiogram may be clinically useful in predicting proximal LCx stenosis and identifying a subset of postinfarction patients with left ventricular dysfunction due to a large infarct size.

Myocardial infarction due to isolated left circumflex or right coronary artery occlusion

The electrocardiographic (ECG) patterns related to clinical spectrum and angiographic features were assessed in 41 patients with first myocardial infarction due to isolated left circumflex coronary artery (LCX) occlusion, and compared to those in 45 patients with right coronary artery (RCA)-related infarction. The occurrence of inferior Q waves was similar in patients with LCX and RCA occlusion, but lateral Q waves and an abnormal R wave in lead V1 were more frequently seen in patients with LCX-related infarction (46% vs 7% and 51% vs 4%, respectively). Compared with patients with LCX-related infarction without an abnormal R wave in lead V1 and those with RCA occlusion, patients with LCX-related infarction and an abnormal R wave in lead V1 associated with inferior and/or lateral Q waves had larger left ventricular end-diastolic and end-systolic volumes, lower ejection fraction, higher incidence of total occlusion of a dominant LCX without collaterals, and more cardiac events during follow-up. The study suggests that the presence of lateral Q waves and an abnormal R wave in lead V1 after myocardial infarction may be a useful marker of LCX occlusion, and that patients with LCX-related infarction may have different status of left ventricular function depending on the size of circulation and the status of residual flow to the infarct region during LCX occlusion.

[Relationship between electrocardiographic pattern and angiographic findings in inferior myocardial infarction]

The relationship between electrocardiographic pattern and angiographic features was assessed in 86 patients with inferior myocardial infarction. Although the occurrence of inferior Q wave was similar in patients with isolated left circumflex (LCX) or right coronary artery (RCA) occlusion, lateral Q wave and abnormal R wave in lead V1 were more frequent in the former. In patients with LCX-related infarction, abnormal R wave in lead V1 associated with inferior and/or lateral Q waves may indicate left ventricular dysfunction, total occlusion of the LCX without collateral circulation, and high cardiac event rate during longterm follow-up.

Assessment of severity of aortic regurgitation by M-mode colour Doppler flow imaging

To assess the value of measuring the aortic regurgitant jet diameter at its origin by M-mode colour Doppler imaging, 82 patients with aortic regurgitation underwent, within 72 h of each other, colour Doppler examination and angiography. After excluding one patient without colour Doppler aortic regurgitation and five with a highly eccentric regurgitant jet, we found a close relationship between the jet diameter at its origin measured by M-mode colour Doppler and the angiographic grade of aortic regurgitation (r = 0.88). A jet diameter greater than or equal to 12 mm identified severe aortic regurgitation (grade III or IV) with a sensitivity of 86.4% and a specificity of 94.4%. In 38 patients, the jet diameter correlated well with the regurgitant fraction measured by a combined haemodynamic-angiographic method (r = 0.88). A jet diameter greater than or equal to 12 mm identified a regurgitant fraction greater than or equal to 40% with a sensitivity of 88.2% and a specificity of 95.2%. This study indicates that the size of the regurgitant jet diameter at its origin measured by M-mode colour Doppler provides a simple and useful measure of the severity of aortic regurgitation. It may allow differentiation between mild or moderate and severe aortic regurgitation and evaluation of regurgitant fraction.

Alternative splicing of the HOX 2.2 homeobox gene in human hematopoietic cells and murine embryonic and adult tissues

The HOX 2.2 homeobox gene is expressed in human hematopoietic cell lines with erythroid features (W.-F. Shen, et al, Proc. Natl. Acad. Sci. 86, 8536-8540, 1989). Both human and murine Hox 2.2 genes contain a single 1 kb intron which interrupts the sequence encoding the proposed homeobox protein. Four human erythroleukemia cell lines express the spliced, homeobox-coding transcript as the major form of message, and variable low amounts of unspliced HOX 2.2 mRNAs. Murine embryonic tissues and adult kidney and uterus contain approximately equal amounts of transcripts containing this intron and mRNAs from which the intron has been excised. The spliced transcript encodes a 224 amino acid homeobox protein, while the unspliced transcript would potentially encode a 140 residue protein containing the same N-terminal sequence but lacking the homeodomain.

Angiographic prediction of cardiac events after first acute transmural myocardial infarction. A prospective study of 108 patients

108 patients with acute myocardial infarction (MI), aged 70 years or younger, underwent left ventriculography and coronary arteriography (mean one month) after infarction and were followed up for an average period of 22 months (range 5-47 months). The contribution of angiographic variables to a first cardiac event (death, recurrent infarction, coronary artery bypass grafting or congestive heart failure) was evaluated with Kaplan-Meier survival curve analysis and long-rank test. Patients with cardiac events had left ventricular dilation, systolic dysfunction, multivessel coronary disease and lack of residual flow to the infarct region. Multivariate analysis showed that left ventricular end-systolic volume (P less than 0.001), end-diastolic volume (P less than 0.01) and the number of the diseased coronary vessels (P less than 0.05) were of significance in predicting the outcome. This prospective study indicates that in survivors of first acute transmural MI, cardiac catheterization performed one month after infarction can provide additive prognostic information that can be used to stratify risk.

End diastolic flow velocity just beneath the aortic isthmus assessed by pulsed Doppler echocardiography: a new predictor of the aortic regurgitant fraction

End diastolic flow velocity just beneath the aortic isthmus was measured within 72 hours of cardiac catheterisation by pulsed Doppler echocardiography in 30 controls and 61 patients with aortic regurgitation. The end diastolic flow velocity was determined at the peak R wave on a simultaneously recorded electrocardiogram. In all controls there was no reverse flow at the end diastole beneath the aortic isthmus. In patients with aortic regurgitation the end diastolic flow velocity correlated well with the angiographic grade of regurgitation (r = 0.81) and regurgitant fraction (r = 0.82). The mean (SD) values were 6.3 (5.2), 12.2 (4.3), 22.1 (5.7), and 34.3 (9.3) cm/s for patients with regurgitant fraction of less than 20%, between 20% and 40%, between 41% and 60%, and greater than 60%, respectively. An end diastolic flow velocity of greater than 18 cm/s predicted a regurgitant fraction of greater than or equal to 40% with a sensitivity of 88.5% and a specificity of 96%. The study suggests that the pulsed Doppler derived end diastolic flow velocity is a useful index in the routine non-invasive assessment of the severity of aortic regurgitation.

Determination of left ventricular inflow by pulsed Doppler echocardiography: influence of mitral orifice area and blood velocity measurements

Pulsed Doppler echocardiography was performed in 30 patients to assess the influence of mitral orifice area and velocity on the determination of mitral stroke volume and inflow. Aortic forward stroke volume and outflow were measured at the centre of the aortic annulus, and compared with mitral flow measurements calculated by three methods. Both mitral stroke volume and inflow derived from an instantaneous velocity-area method showed an excellent correlation with aortic flow measurements. The other two methods, which determined mitral stroke volume and inflow based on a mean mitral valve area and diastolic velocity integral, significantly underestimated mitral flow measurements. This study indicates that the instantaneous velocity-area method offers a reliable means for quantitating left ventricular inflow.

Spontaneous alterations in left ventricular regional wall motion after acute myocardial infarction

For assessing the relationship between the left ventricular (LV) wall motion abnormalities and the status of residual flow to the infarcted region, the extent of coronary artery disease and one-year outcome, 60 patients with a first transmural, Q-wave myocardial infarction (MI) underwent serial echocardiographic examinations. The abnormal wall motion (AWM) score was calculated, and the cardiac events (death, reinfarction, severe ventricular arrhythmia or congestive heart failure) after discharge were recorded. The AWM score of the infarcted area was higher in patients with total occlusion than in those with subtotal occlusion (anterior MI: 14.6 +/- 2.4 vs 7.2 +/- 2.1; inferior MI: 9.7 +/- 2.1 vs 5.1 +/-1.2, all P less than 0.01). Regional wall motion of the noninfarcted area was preserved in patients with single vessel disease but decreased in those with multivessel disease. In patients who developed cardiac events in follow-up period a higher AWM (16.4 +/- 3.7) was found than in those who did not (8.9 +/- 3.1, P less than 0.05). A score of greater than 13 had a strong prediction of cardiac events after acute MI, with a sensitivity of 81%, specificity of 94% and positive predictive accuracy of 88%.

Hemodynamic and metabolic basis of impaired exercise tolerance in patients with severe left ventricular dysfunction

Hemodynamic and metabolic changes were measured at rest and during exercise in 23 patients with chronic heart failure and in 6 control subjects. Exercise was limited by leg fatigue in both groups and capacity was 40% lower in the patients with failure. At rest, comparing patients with control subjects, heart rate and right atrial and pulmonary wedge pressure were higher; cardiac output, stroke volume and work indexes and ejection fraction were lower; mean arterial and right atrial pressure and systemic resistance were similar. During all phases of exercise in patients with heart failure, pulmonary wedge pressure and systemic vascular resistance were higher and pulmonary vascular resistance remained markedly elevated compared with values in control subjects. Cardiac output was lower in the patients with failure, but appeared to have the same physiologic distribution in both groups during exercise. Although arterial-femoral venous oxygen content difference was higher in patients with heart failure, this increase did not compensate for the reduced blood flow. Even though the maximal oxygen consumption was significantly reduced, femoral venous lactate and pH values were higher than values in control subjects, but femoral venous pH was similar in both groups at their respective levels of maximal exercise. Ejection fraction was lower in those with heart failure at rest and did not increase with exercise. Ventilation in relation to oxygen consumption was higher in patients with failure than in control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Beneficial effect of residual flow to the infarct region on left ventricular volume changes after acute myocardial infarction

To determine the relationship between alterations in left ventricular (LV) volumes and residual flow to the infarct region after myocardial infarction (MI), 57 patients with a first acute transmural MI underwent two-dimensional echocardiography within 48 hours of infarction and after 1 month. A reduction in ST segment elevation by greater than or equal to 35% of the peak value of ST segment elevation within the initial 6 hours was used as an indirect indicator for early reperfusion of the infarct-related artery (IRA). IRA patency and collateral circulation were assessed by coronary arteriography performed at 1 month. LV volumes increased in patients with a persistent ST segment elevation within the initial 6 hours of infarction and in those with a totally occluded IRA without collaterals. However, LV volumes were unchanged in patients with early reperfusion and in those who had subtotally occluded IRA or who had collateral circulation. LV dilation (greater than or equal to 20% increase in end-diastolic volume) occurred less often when early reperfusion and angiographically patent IRA or collateral supply to the infarct zone were present. This prospective study indicates that residual flow to the infarct region may exert a beneficial effect on LV volume changes after acute MI.

[Value of angina pectoris after myocardial infarction in predicting the extent of coronary artery disease]

Clinical, hemodynamic, and angiographic data were examined in 53 patients who underwent catheterization within 6 months of a documented first acute transmural myocardial infarction. The patients were divided according to the presence (23 patients) or absence (30 patients) of angina pectoris 1 month after infarction (group I and group II). Group I patients had more severe coronary artery disease and a greater prevalence of multivessel disease than group II patients. Partial preservation of segmental wall function in group I was related to the presence of collateral vessels. In patients with single vessel disease, the incidence of spontaneous recanalization of the infarct-related artery was higher in group I as compared with that in group II. It is concluded that angina pectoris after myocardial infarction suggests multivessel disease or infarct-related artery recanalization. Coronary arteriography may be advised in order to select adequate therapeutic interventions and improve prognosis in these patients.