Author Correction: Increasing CO2 threatens human nutrition.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

MORE PANICLES 3, a natural allele of OsTB1/FC1, impacts rice yield in paddy fields at elevated CO2 levels.

Improving crop yield potential through an enhanced response to rising atmospheric CO2 levels is an effective strategy for sustainable crop production in the face of climate change. Large-sized panicles (containing many spikelets per panicle) have been a recent ideal plant architecture (IPA) for high-yield rice breeding. However, few breeding programs have proposed an IPA under the projected climate change. Here, we demonstrate through the cloning of the rice (Oryza sativa) quantitative trait locus for MORE PANICLES 3 (MP3) that the improvement in panicle number increases grain yield at elevated atmospheric CO2 levels. MP3 is a natural allele of OsTB1/FC1, previously reported as a negative regulator of tiller bud outgrowth. The temperate japonica allele advanced the developmental process in axillary buds, moderately promoted tillering, and increased the panicle number without negative effects on the panicle size or culm thickness in a high-yielding indica cultivar with large-sized panicles. The MP3 allele, containing three exonic polymorphisms, was observed in most accessions in the temperate japonica subgroups but was rarely observed in the indica subgroup. No selective sweep at MP3 in either the temperate japonica or indica subgroups suggested that MP3 has not been involved and utilized in artificial selection during domestication or breeding. A free-air CO2 enrichment experiment revealed a clear increase of grain yield associated with the temperate japonica allele at elevated atmospheric CO2 levels. Our findings show that the moderately increased panicle number combined with large-sized panicles using MP3 could be a novel IPA and contribute to an increase in rice production under climate change with rising atmospheric CO2 levels.

Increasing CO2 threatens human nutrition.

Dietary deficiencies of zinc and iron are a substantial global public health problem. An estimated two billion people suffer these deficiencies, causing a loss of 63 million life-years annually. Most of these people depend on C3 grains and legumes as their primary dietary source of zinc and iron. Here we report that C3 grains and legumes have lower concentrations of zinc and iron when grown under field conditions at the elevated atmospheric CO2 concentration predicted for the middle of this century. C3 crops other than legumes also have lower concentrations of protein, whereas C4 crops seem to be less affected. Differences between cultivars of a single crop suggest that breeding for decreased sensitivity to atmospheric CO2 concentration could partly address these new challenges to global health.

Effects of Elevated Atmospheric CO2 on Respiratory Rates in Mature Leaves of Two Rice Cultivars Grown at a Free-Air CO2 Enrichment Site and Analyses of the Underlying Mechanisms.

Respiratory CO2 efflux and O2 uptake rates in leaves change in response to the growth CO2 concentration ([CO2]). The degrees of change vary depending on the responses of cellular processes such as nitrogen (N) assimilation and accumulation of organic acids to growth [CO2]. However, the underlying mechanisms remain unclear. Here, we examined the respiratory characteristics of mature leaves of two rice varieties with different yield capacities at different growth stages under ambient and elevated [CO2] conditions at a free-air CO2 enrichment site. We also examined the effect of increased water temperature on leaf respiration. We measured the rates of CO2 efflux and O2 uptake, and determined N contents, primary metabolite contents and maximal activities of respiratory enzymes. The leaf CO2 efflux rates decreased in plants grown at elevated [CO2] in both varieties, and were higher in high-yielding Takanari than in Koshihikari. The leaf O2 uptake rates showed little change with respect to growth [CO2] and variety. The increased water temperature did not significantly affect the CO2 efflux and O2 uptake rates. The N and amino acid contents were significantly higher in Takanari than in Koshihikari. The enhanced N assimilation in Takanari may have consumed more respiratory NADH, leading to higher CO2 efflux rates. In Koshihikari, the ratio of tricarboxylic acid (TCA) cycle intermediates changed and maximal activities of enzymes in the TCA cycle decreased at elevated [CO2]. Therefore, the decreased rates of CO2 efflux in Koshihikari may be due to the decreased activities of TCA cycle enzymes at elevated [CO2].

Increasing canopy photosynthesis in rice can be achieved without a large increase in water use-A model based on free-air CO2 enrichment.

Achieving higher canopy photosynthesis rates is one of the keys to increasing future crop production; however, this typically requires additional water inputs because of increased water loss through the stomata. Lowland rice canopies presently consume a large amount of water, and any further increase in water usage may significantly impact local water resources. This situation is further complicated by changing the environmental conditions such as rising atmospheric CO2 concentration ([CO2 ]). Here, we modeled and compared evapotranspiration of fully developed rice canopies of a high-yielding rice cultivar (Oryza sativa L. cv. Takanari) with a common cultivar (cv. Koshihikari) under ambient and elevated [CO2 ] (A-CO2 and E-CO2 , respectively) via leaf ecophysiological parameters derived from a free-air CO2 enrichment (FACE) experiment. Takanari had 4%-5% higher evapotranspiration than Koshihikari under both A-CO2 and E-CO2 , and E-CO2 decreased evapotranspiration of both varieties by 4%-6%. Therefore, if Takanari was cultivated under future [CO2 ] conditions, the cost for water could be maintained at the same level as for cultivating Koshihikari at current [CO2 ] with an increase in canopy photosynthesis by 36%. Sensitivity analyses determined that stomatal conductance was a significant physiological factor responsible for the greater canopy photosynthesis in Takanari over Koshihikari. Takanari had 30%-40% higher stomatal conductance than Koshihikari; however, the presence of high aerodynamic resistance in the natural field and lower canopy temperature of Takanari than Koshihikari resulted in the small difference in evapotranspiration. Despite the small difference in evapotranspiration between varieties, the model simulations showed that Takanari clearly decreased canopy and air temperatures within the planetary boundary layer compared to Koshihikari. Our results indicate that lowland rice varieties characterized by high-stomatal conductance can play a key role in enhancing productivity and moderating heat-induced damage to grain quality in the coming decades, without significantly increasing crop water use.

Role of dental sleep medicine in management of patients with obstructive sleep apnea disorders using a team approach.

OBJECTIVE: Obstructive sleep apnea (OSA) is a significant social and health issue. An integrated multidisciplinary approach to OSA management may be the most effective owing to its multifactorial etiology. In this study, we evaluated the frequency and efficacy of various treatment modalities for OSA administered via an integrated care delivery model, and assessed the role of dental sleep medicine as part of a multidisciplinary team. MATERIALS AND METHODS: We retrospectively evaluated 1115 patients with OSA treated at the Tokyo Medical University Hospital's Outpatient Clinic for OSA by a multidisciplinary team under one roof. The various treatment methods included the following: continuous positive airway pressure (CPAP), oral appliance (OA), surgery, and behavioral treatment. RESULTS: The patient number of study group was as follows: 771 (69.1%) CPAP; 240 (21.5%) OA; 76 (6.8%) behavioral treatment and 28 (3%) surgery. Because significantly fewer patients underwent surgery, there was a discrepancy between the recommended first-choice treatment and the actual treatment. A statistically significant number of younger patients in each treatment group underwent surgery. Success rate of OA and MMA were 74.4 and 80%, respectively. CONCLUSIONS: Proper selection of primary treatment to manage patients with OSA was possible under one-roof system that included dental sleep medicine.

Rice grain yield and quality responses to free-air CO2 enrichment combined with soil and water warming.

Rising air temperatures are projected to reduce rice yield and quality, whereas increasing atmospheric CO2 concentrations ([CO2 ]) can increase grain yield. For irrigated rice, ponded water is an important temperature environment, but few open-field evaluations are available on the combined effects of temperature and [CO2 ], which limits our ability to predict future rice production. We conducted free-air CO2 enrichment and soil and water warming experiments, for three growing seasons to determine the yield and quality response to elevated [CO2 ] (+200 µmol mol(-1) , E-[CO2 ]) and soil and water temperatures (+2 °C, E-T). E-[CO2 ] significantly increased biomass and grain yield by approximately 14% averaged over 3 years, mainly because of increased panicle and spikelet density. E-T significantly increased biomass but had no significant effect on the grain yield. E-T decreased days from transplanting to heading by approximately 1%, but days to the maximum tiller number (MTN) stage were reduced by approximately 8%, which limited the panicle density and therefore sink capacity. On the other hand, E-[CO2 ] increased days to the MTN stage by approximately 4%, leading to a greater number of tillers. Grain appearance quality was decreased by both treatments, but E-[CO2 ] showed a much larger effect than did E-T. The significant decrease in undamaged grains (UDG) by E-[CO2 ] was mainly the result of an increased percentage of white-base grains (WBSG), which were negatively correlated with grain protein content. A significant decrease in grain protein content by E-[CO2 ] accounted in part for the increased WBSG. The dependence of WBSG on grain protein content, however, was different among years; the slope and intercept of the relationship were positively correlated with a heat dose above 26 °C. Year-to-year variation in the response of grain appearance quality demonstrated that E-[CO2 ] and rising air temperatures synergistically reduce grain appearance quality of rice.

Obstructive Sleep Apnea as Possible Causal Factor for Visit-to-Visit Blood Pressure Variability.

BACKGROUND: Recent studies have shown that visit-to-visit blood pressure variability (BPV) is an independent risk factor for cardiovascular disease. However, it has not been clarified whether obstructive sleep apnea (OSA) is associated with visit-to-visit BPV. METHODS AND RESULTS: The 56 subjects with OSA and 26 control subjects without OSA were examined. Office BP was measured on 5 separate consecutive occasions prior to a polysomnography examination. The visit-to-visit BPV was expressed as the standard deviation and the coefficient of variation of the 5 systolic BP measurements. In subjects with an apnea-hypopnea index (AHI) of more than 20 episodes per hour, the visit-to-visit BPV was also measured after the start of continuous positive airway pressure (CPAP) therapy. Overall, the AHI positively correlated with the standard deviation and the coefficient of variation of systolic BP. In a multivariate analysis, the plasma noradrenaline level and the AHI were independently and positively correlated with the standard deviation and the coefficient of variation of the systolic BP. Among the patients who underwent CPAP therapy, good adherence with CPAP therapy significantly reduced the visit-to-visit BPV. CONCLUSIONS: OSA is associated with abnormal visit-to-visit BPV and sympathetic activation seems to be related in some way. (Circ J 2016; 80: 1787-1794).

Continuous positive airway pressure treatment improves cardiovascular outcomes in elderly patients with cardiovascular disease and obstructive sleep apnea.

Obstructive sleep apnea (OSA) is associated with the progression of cardiovascular disease (CVD), particularly in the middle-aged population. However, the clinical importance of OSA as a risk for CVD in the elderly population remains controversial. Moreover, evidence for the effectiveness of continuous positive airway pressure (CPAP) treatment for the secondary prevention of CVD in elderly patients is lacking. We assessed whether CPAP treatment improves cardiovascular outcomes in elderly patients with OSA and CVD. In this retrospective cohort study, we enrolled 130 elderly patients aged 65-86 years with moderate to severe OSA (apnea-hypopnea index ≥15/h) and a history of hospitalization due to CVD, who underwent polysomnography between November 2004 and July 2011. Patients were divided into the CPAP group (n = 64) or untreated OSA group (n = 66). The main outcome measures were cardiovascular death and hospitalization due to CVD. During the mean follow-up period of 32.9 ± 23.8 (standard deviation) months, 28 (21.5 %) patients either died or were hospitalized. The Kaplan-Meier curves indicated that event-free survival was significantly lower in the untreated OSA group than in the CPAP group (P < 0.005). A multivariate analysis showed that the risk was significantly increased in the untreated OSA group (hazard ratio 5.13; 95 % confidence interval 1.01-42.0; P < 0.05). Moderate to severe OSA not treated with CPAP was an independent risk factor for relapse of a CVD event, and adequate CPAP treatment improved cardiovascular outcomes in elderly patients.

Severe obstructive sleep apnea increases left atrial volume independently of left ventricular diastolic impairment.

PURPOSE: Severe obstructive sleep apnea (OSA) directly impairs left ventricular (LV) diastolic function. Left atrial volume index (LAVI), an independent predictor of future cardiovascular events, is also related to OSA severity. This study aimed to assess whether OSA is associated with an increase in LAVI independently of LV diastolic function. METHODS: Two hundred six OSA patients (apnea hypopnea index, AHI ≥ 5/h) without cardiac disease, hypertension, and diabetes were enrolled. They underwent overnight fully attended polysomnography and 2-dimensional echocardiography in order to estimate LA volumes and LV diastolic function which was assessed by the ratio of transmitral early diastolic flow velocity to late diastolic flow velocity (E/A), deceleration time, and mitral annular velocity (e') which was derived from tissue Doppler imaging. Patients were divided into two groups based on AHI, namely, group M (5 ≤ AHI < 30/h) and group S (AHI ≥ 30/h). RESULTS: The LAVI value in group S was significantly larger than that in group M (20 ± 5 vs. 23 ± 5 mL/m(2), P < 0.001). E/A in group S was significantly lower than that in group M (P < 0.001), whereas the ratio of E to e' (E/e') in group S was significantly higher than that in group M (P < 0.001). AHI showed a statistically significant correlation with LAVI (P < 0.001). On multivariate linear regression analysis, severe OSA was independently related with LAVI even after adjusting for age, sex, systolic blood pressure, body mass index, and measurements of LV diastolic function (P = 0.04). CONCLUSIONS: Severe OSA itself might directly increase LAVI, independently of LV diastolic function.

Do the rich always become richer? Characterizing the leaf physiological response of the high-yielding rice cultivar Takanari to free-air CO2 enrichment.

The development of crops which are well suited to growth under future environmental conditions such as higher atmospheric CO2 concentrations ([CO2]) is essential to meeting the challenge of ensuring food security in the face of the growing human population and changing climate. A high-yielding indica rice variety (Oryza sativa L. cv. Takanari) has been recently identified as a potential candidate for such breeding, due to its high productivity in present [CO2]. To test if it could further increase its productivity under elevated [CO2] (eCO2), Takanari was grown in the paddy field under season-long free-air CO2 enrichment (FACE, approximately 200 µmol mol(-1) above ambient [CO2]) and its leaf physiology was compared with the representative japonica variety 'Koshihikari'. Takanari showed consistently higher midday photosynthesis and stomatal conductance than Koshihikari under both ambient and FACE growth conditions over 2 years. Maximum ribulose-1,5-bisphosphate carboxylation and electron transport rates were higher for Takanari at the mid-grain filling stage in both years. Mesophyll conductance was higher in Takanari than in Koshihikari at the late grain-filling stage. In contrast to Koshihikari, Takanari grown under FACE conditions showed no decrease in total leaf nitrogen on an area basis relative to ambient-grown plants. Chl content was higher in Takanari than in Koshihikari at the same leaf nitrogen level. These results indicate that Takanari maintains its superiority over Koshihikari in regards to its leaf-level productivity when grown in elevated [CO2] and it may be a valuable resource for rice breeding programs which seek to increase crop productivity under current and future [CO2].

Fully automated, high-throughput instrumentation for measuring the δ13C value of methane and application of the instrumentation to rice paddy samples.

RATIONALE: The stable carbon isotope ratio ((13)C/(12)C or δ(13)C value) of methane (CH4) produced in methanogenic environments contains information about primary source material, CH4 production pathways, degree of oxidation, and transport. However, the availability of δ(13)C-CH4 data is severely limited because isotope analysis methods are low throughput, owing primarily to the need for manual processing steps. High-throughput, fully automated measurement is necessary to facilitate the use of the δ(13)C signature in understanding CH4 biogeochemistry. METHODS: We modified a conventional continuous-flow (CF) gas chromatography/combustion/isotope ratio mass spectrometry (IRMS) instrument system by incorporating (i) automated sample injection, (ii) a newly developed temperature-control unit for preconcentration and cryofocus traps, and (iii) an automatic system for liquid-nitrogen refilling. The system, which could run unattended for 1 day, was used to obtain δ(13)C-CH4 data for CH4 samples collected from an irrigated rice paddy with an automated closed-chamber system. RESULTS: Using the fully automated CF-IRMS system, we measured δ(13)C-CH4 data for 77 samples during a 21.5-h continuous run (17 min per sample) with high precision (1σ = 0.11‰, reproducibility) and moderate consumption of liquid nitrogen (11 L). Application of the system to CH4 samples obtained from the rice paddy revealed distinct seasonal and diurnal variations in δ(13)C values with the highest temporal resolution ever reported. CONCLUSIONS: A fully automated, high-throughput system for the measurement of δ(13)C-CH4 values was developed and used to analyze air samples obtained from a rice paddy. Our results demonstrate the high potential of this system for obtaining δ(13)C data useful for process-level understanding of CH4 biogeochemistry with respect to spatiotemporal variation of CH4 sources and how that variation is affected by environmental and management factors.

Planting geometry as a pre-screening technique for identifying CO2 responsive rice genotypes: a case study of panicle number.

Identifying CO(2) responsive genotypes is a major target for enhancing crop productivity under future global elevated atmospheric CO(2) concentration ([CO(2)]). However, [CO(2)]-fumigation facilities are extremely expensive and are not easily accessible, and are limited in space for large-scale screening. Hence, reliable donors for initiating [CO(2)]-responsive breeding programs are not in place for crops, including rice. We propose a simple and novel phenotyping method for identifying [CO(2)]-responsive genotypes, and quantify the responsiveness to low planting density over 4-year trials across both temperate and tropical conditions. Panicle number per plant is the key determinant of grain yield and hence was the focus trait across all our trials. In temperate climate, a 3-season field screening using 127 diverse rice genotypes and employing two planting densities (normal and low density) was conducted. Two japonica genotypes were selected based on their higher responsiveness to low planting density as candidates for validating the proposed phenotyping protocol as a pre-screen for [CO(2)]-responsiveness. The approach using the two selected candidates and three standard genotypes was confirmed using a free-air CO(2) enrichment facility and temperature gradient chambers under elevated [CO(2)]. In tropical climate, we grew three rice cultivars, previously identified for their [CO(2)]-responsiveness, at two planting densities. The experiments provided confirmation that responsiveness to low planting density was correlated with that of [CO(2)]-responsiveness across both the temperate and tropical conditions. The planting density would be useful pre-screening method for testing large panels of diverse germplasm at low cost complemented by available CO(2) -control facilities for final validation of candidates from the pre-screens.

Usefulness of phase analysis to differentiate ischemic and non-ischemic etiologies of left ventricular systolic dysfunction in patients with heart failure.

BACKGROUND: The detection of significant coronary artery disease (CAD) in patients with heart failure (HF) from left ventricular (LV) systolic dysfunction is crucial. We evaluated the usefulness of LV mechanical dyssynchrony as assessed by phase analysis compared with conventional gated single-photon emission computed tomography to identify ischemic etiology in patients with HF. METHODS AND RESULTS: Forty-one consecutive patients who were initially admitted to hospital due to HF resulting from systolic dysfunction were evaluated. All patients underwent cardiac catheterization. LV mechanical dyssynchrony was evaluated using SyncTool™ to obtain the phase SD and histogram bandwidth. The changes in phase SD and histogram bandwidth with stress were calculated. The summed stress score, summed difference score, and changes in phase SD and histogram bandwidth with stress were greater in 26 patients with CAD than in 15 patients without CAD (P=0.001 and P=0.01). On multivariate analysis a phase SD of >14° (odds ratio [OR], 16.7) and a summed stress score of >17 (OR, 8.0) best differentiated LV dysfunction of ischemic and non-ischemic etiologies, with a sensitivity of 89% and a specificity of 87% (χ(2)=20), compared with summed stress score only (sensitivity, 46%; specificity, 87%; χ(2)=4.5). CONCLUSIONS: The addition of phase analysis to conventional perfusion analysis enables better differentiation of the etiology of HF in patients with systolic dysfunction.

Diagnostic performance of a novel cadmium-zinc-telluride gamma camera system assessed using fractional flow reserve.

BACKGROUND: Although the novel cadmium-zinc-telluride (CZT) camera system provides excellent image quality, its diagnostic value using thallium-201 as assessed on coronary angiography (CAG) and fractional flow reserve (FFR) has not been validated. METHODS AND RESULTS: To evaluate the diagnostic accuracy of the CZT ultrafast camera system (Discovery NM 530c), 95 patients underwent stress thallium-201 single-photon emission computed tomography (SPECT) and then CAG within 3 months. Image acquisition was performed in the supine and prone positions after stress for 5 and 3 min, respectively, and in the supine position at rest for 10 min. Significant stenosis was defined as ≥90% diameter narrowing on visual estimation, or a lesion with <90% and ≥50% stenosis and FFR ≤0.75. To detect individual coronary stenosis, the respective sensitivity, specificity, and accuracy were 90%, 64%, and 78% for left anterior descending coronary artery stenosis, 78%, 84%, and 81% for left circumflex stenosis, and 83%, 47%, and 60% for right coronary artery (RCA) stenosis. The combination of prone and supine imaging had a higher specificity for RCA disease than supine imaging alone (65% vs. 47%), with an improvement in accuracy from 60% to 72%. CONCLUSIONS: Using thallium-201 with short acquisition time, combined with prone imaging, CZT SPECT had a high diagnostic yield in detecting significant coronary stenosis as assessed using FFR.

The effects of free-air CO2 enrichment (FACE) on carbon and nitrogen accumulation in grains of rice (Oryza sativa L.).

Rising atmospheric CO2 concentrations will probably increase rice (Oryza sativa L.) yield but decrease grain nitrogen (GN) concentration. Grains attached to different positions in the panicles differ greatly in weight and quality, but their responses to elevated CO2 (e[CO2]) are poorly understood, which limits our understanding of the mechanisms of yield enhancement and quality degradation. Thus a free-air CO2 enrichment experiment was conducted to examine the effects of e[CO2] on grain mass (GM), grain carbon (GC), and GN accumulation in the spikelets attached to the upper primary rachis branch (superior spikelets; SS) and those attached to the lower secondary rachis (inferior spikelets; IS). e[CO2] stimulated the rice yield by 13% but decreased the N concentration in the panicle by 7% when averaged over two levels of N fertilizations (P < 0.01). The responses of SS and IS to e[CO2] were different particularly under higher N supply. For SS, e[CO2] decreased GN by 24% (P < 0.01) but did not affect GM. For IS, e[CO2] increased GM by 13% (P < 0.05) but GN was not affected. The reduction of GN due to e[CO2] started to appear at the beginning of grain filling. These results suggest that future [CO2] levels probably stimulate the grain growth of IS, most of which are not marketable due to limited size, at the expense of GN reduction in SS. Translocation of N from SS to IS may be a possible mechanism for reduction in GN of SS. This may degrade the grain quality of marketable rice under e[CO2].

Relationship of SYNTAX score to myocardial ischemia as assessed on myocardial perfusion imaging.

BACKGROUND: Although the Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) score is used to characterize coronary anatomy based on 9 anatomic criteria such as lesion location and complexity, the relationship between SYNTAX score and myocardial ischemia has yet to be elucidated. METHODS AND RESULTS: A total of 158 consecutive patients with suspected or known coronary artery disease (CAD), who underwent both (99m)Tc-sestamibi single-photon emission computed tomography (SPECT) and coronary angiography, were evaluated. Stress SPECT was assessed using a 17-segment model, and the percentage of the myocardial defect scores (DS) was calculated. In 37 patients with intermediate-high SYNTAX scores (>22), the number of men and the prevalence of multi-vessel CAD were significantly higher, and the % stress and ischemic DS were significantly greater than in 121 patients with low SYNTAX scores (≤22). Coronary risk factors, however, were similar between the 2 groups. The % stress and ischemic DS significantly correlated with SYNTAX score. In patients with a low SYNTAX score, % stress and ischemic DS also significantly correlated with the SYNTAX score, whereas no such correlation was observed in the intermediate-high SYNTAX score group. CONCLUSIONS: SYNTAX score correlated well with myocardial ischemia as assessed on stress SPECT in general. The higher the SYNTAX score, however, the less clear was the correlation with the extent of myocardial ischemia.

Postischemic myocardial stunning is superior to transient ischemic dilation for detecting multivessel coronary artery disease.

BACKGROUND: Although poststress myocardial stunning is regarded as a marker for severe coronary artery disease (CAD), no study has yet compared the diagnostic value of poststress stunning with transient ischemic dilation (TID) of the left ventricle (LV) for detecting multivessel CAD. METHODS AND RESULTS: A total of 271 patients with suspected or known CAD underwent adenosine triphosphate (ATP) loading and at-rest gated single-photon emission computed tomography. We assessed myocardial perfusion with a 20-segment model, and analyzed the changes in LV volumetric analysis induced by ATP and an automatically derived TID ratio. In 147 patients with multivessel CAD, the prevalence of multi-territorial ischemia was higher, and the post-ATP increase in end-systolic volume (ESV) and TID ratio were greater, than in the 124 with insignificant or single-vessel CAD (P<0.0001, for all cases). The receiver-operating characteristic curves analysis revealed cutoff values for ESV of 5 ml and a TID ratio of 1.11. Multivariate logistic regression analysis revealed that the combination of a poststress increase in ESV of ≥5 ml and multi-territorial ischemia best identified multivessel CAD, with a sensitivity of 78% and a specificity of 84%, whereas the TID ratio was not shown to be an independent predictor. CONCLUSIONS: Post-ATP stress myocardial stunning is superior to the TID ratio for detecting multivessel CAD.

Diagnostic value of left ventricular dyssynchrony after exercise and at rest in the detection of multivessel coronary artery disease on single-photon emission computed tomography.

BACKGROUND: Although stress-induced left ventricular (LV) wall motion abnormality is a well-known marker for extensive coronary artery disease (CAD), no study has yet analyzed whether phase analysis of exercise-induced LV mechanical dyssynchrony may have enhanced diagnostic value over conventional perfusion analysis in the detection of multivessel CAD. METHODS AND RESULTS: A total of 278 patients with suspected or confirmed CAD underwent both exercise stress (99m)Tc-sestamibi gated single-photon emission computed tomography and coronary angiography. LV mechanical dyssynchrony was evaluated using the SyncTool to obtain the phase SD and histogram bandwidth. In the detection of 128 patients with multivessel CAD, a summed stress score (SSS) of ≥9 showed a sensitivity of 84% and a specificity of 53%, while an increase in phase SD of ≥4.4° and a bandwidth of ≥14° after exercise had sensitivities of 74% and 68%, and specificities of 84% and 91%, respectively. On multivariate analysis the combination of post-stress increases in phase SD, histogram bandwidth, transient ischemic dilation (TID) ratio and SSS best identified multivessel CAD (sensitivity 77%, specificity 88%, χ(2)=181.8), compared with TID ratio and SSS only (sensitivity 70%, specificity 76%, χ(2)=68.9). CONCLUSIONS: The addition of phase analysis to evaluate exercise-induced LV mechanical dyssynchrony on conventional perfusion analysis enabled better identification of patients with multivessel CAD.

Obstructive sleep apnea as a potential risk factor for aortic disease.

Obstructive sleep apnea (OSA) is not only a cause of hypertension; it also possibly affects the pathogenesis and progression of aortic disease because an inspiratory effort-induced increase in negative intrathoracic pressure generates mechanical stress on the aortic wall. The objective of the present study was to examine the incidence by location of OSA as a complication in patients with aortic aneurysm and patients with aortic dissection (AD). An overnight sleep study was conducted in the following study groups: the aortic disease group (n = 95) consisting of patients with thoracic aortic aneurysm (TAA, n = 32), patients with abdominal aortic aneurysm (AAA, n = 36), and patients with AD (n = 27); and a control group (n = 32), consisting of patients with coronary risk factors who were matched with the aortic disease group for age, gender, and body mass index (BMI). The 3% oxygen desaturation index (ODI) was significantly higher in all the TAA, AAA, and AD groups (P = 0.045, P = 0.003, and P = 0.005, respectively) than in the control group. The incidence of moderate to severe OSA [apnea hypopnea index (AHI) ≥15 events/h] was significantly higher in the first three groups (P = 0.026, P = 0.001, P = 0.003, respectively) than in the control group, while no significant difference was found between the TAA group and the AAA group with respect to these variables. Furthermore, no significant differences were found between the thoracic AD subgroup and the abdominal AD subgroup with respect to AHI and 3% ODI, as well as with respect to the incidences of moderate to severe OSA. Patients with TAA, patients with AAA, and patients with AD showed high incidences of moderate to severe OSA. Although this result suggests that OSA may be one of risks for aortic disease, unelucidated mechanism(s) other than negative intrathoracic pressure may be involved in the pathogenesis of aortic disease.