Prognostic Implications of Individual and Combinations of Resting and Hyperemic Coronary Pressure and Flow Parameters

Background

Coronary pressure- and flow-derived parameters have prognostic value.

Objectives

This study aims to investigate the individual and combined prognostic relevance of pressure and flow parameters reflecting resting and hyperemic conditions.

Methods

A total of 1,971 vessels deferred from revascularization after invasive pressure and flow assessment were included from the international multicenter registry. Abnormal resting pressure and flow were defined as distal coronary pressure/aortic pressure ≤0.92 and high resting flow (1/resting mean transit time >2.4 or resting average peak flow >22.7 cm/s), and abnormal hyperemic pressure and flow as fractional flow reserve ≤0.80 and low hyperemic flow (1/hyperemic mean transit time <2.2 or hyperemic average peak flow <25.0 cm/s), respectively. The clinical endpoint was target vessel failure (TVF), myocardial infarction (MI), or cardiac death at 5 years.

Results

The mean % diameter stenosis was 46.8% ± 16.5%. Abnormal pressure and flow were independent predictors of TVF and cardiac death/MI (all P < 0.05). The risk of 5-year TVF or MI/cardiac death increased proportionally with neither, either, and both abnormal resting pressure and flow, and abnormal hyperemic pressure and flow (all P for trend < 0.001). Abnormal resting pressure and flow were associated with a higher rate of TVF or MI/cardiac death in vessels with normal fractional flow reserve; this association was similar for abnormal hyperemic pressure and flow in vessels with normal resting distal coronary pressure/aortic pressure (all P < 0.05).

Conclusions

Abnormal resting and hyperemic pressure and flow were independent prognostic predictors. The abnormal flow had an additive prognostic value for pressure in both resting and hyperemic conditions with complementary prognostic between resting and hyperemic parameters.

Hyperaemic and non-hyperaemic pressure indices of coronary stenosis severity in patients with chronic kidney disease

Background

Evidence regarding the use of pressure indices for the assessment of coronary stenoses in patients with chronic kidney disease (CKD) is scarce.

Methods

We assessed the relation between eGFR, FFR and resting Pd/Pa in 1147 consecutive patients (1316 vessels) included in the International Collaboration of Comprehensive Physiologic Assessment Study. We also compared FFR and Pd/Pa against a standardized cut-off of coronary flow reserve (CFR&lt;2.0). Finally, we examined the occurrence of vessel-oriented composite outcome (VOCO: cardiac death, vessel-specific revascularization, vessel-specific myocardial infarction) across negative/positive results of both FFR and CFR in patients with and without CKD.

Results

FFR increases as renal function worsens (beta −10.5, 95% CI −20.0 to −11.03, p=0.030), a relation that was not seen with resting Pd/Pa (beta −6.14, 95% CI −19.9 to 6.78, p=0.351). Both indices had similar diagnostic accuracies for the detection of a CFR&lt;2.0 in the presence of CKD (AUC 0.629 for FFR vs 0.663 for resting Pd/Pa, p=0.192). However, CKD patients showed a higher proportion of vessels with negative FFR but low CFR (24.5% vs 13.4%, p=0.015).

CFR decreased linearly with deteriorating eGFR, and this was mainly driven by higher resting coronary flow in CKD patients (p=0.026), while hyperaemic coronary flow remained similar (p=0.403). IMR did not change significantly with eGFR (beta −0.02, 95% −0.09 to 0.05, p=0.557).

The incidence of VOCO was higher in patients with CKD and FFR&gt;0.80 when compared to non-CKD patients and FFR&gt;0.80 (12.7% vs 6.90%, p=0.062). Prognosis was worse for those with CKD, negative FFR and CFR&lt;2.0 (20.59% vs. 8.44% in non-CKD, p=0.038).

Conclusions

The assessment of a given coronary stenosis in patients with CKD with either FFR or resting Pd/Pa is equivalent when compared to underlying coronary flow. In CKD, impaired CFR is caused by a state of increased resting flow. The assessment of CFR on top of standard pressure wire examination significantly improves prognostic stratification in CKD patients.

Funding Acknowledgement

Type of funding sources: None.

Impact of Cardiovascular Risk Factors and Cardiovascular Diseases on Outcomes in Patients Hospitalized with COVID-19 in Daegu Metropolitan City

BACKGROUND

Data regarding the association between preexisting cardiovascular risk factors (CVRFs) and cardiovascular diseases (CVDs) and the outcomes of patients requiring hospitalization for coronavirus disease 2019 (COVID-19) are limited. Therefore, the aim of this study was to investigate the impact of preexisting CVRFs or CVDs on the outcomes of patients with COVID-19 hospitalized in a Korean healthcare system.

METHODS

Patients with COVID-19 admitted to 10 hospitals in Daegu Metropolitan City, Korea, were examined. All sequentially hospitalized patients between February 15, 2020, and April 24, 2020, were enrolled in this study. All patients were confirmed to have COVID-19 based on the positive results on the polymerase chain reaction testing of nasopharyngeal samples. Clinical outcomes during hospitalization, such as requiring intensive care and invasive mechanical ventilation (MV) and death, were evaluated. Moreover, data on baseline comorbidities such as a history of diabetes, hypertension, dyslipidemia, current smoking, heart failure, coronary artery disease, cerebrovascular accidents, and other chronic cardiac diseases were obtained.

RESULTS

Of all the patients enrolled, 954 (42.0%) had preexisting CVRFs or CVDs. Among the CVRFs, the most common were hypertension (28.8%) and diabetes mellitus (17.0%). The prevalence rates of preexisting CVRFs or CVDs increased with age (P < 0.001). The number of patients requiring intensive care (P < 0.001) and invasive MV (P < 0.001) increased with age. The in-hospital death rate increased with age (P < 0.001). Patients requiring intensive care (5.3% vs. 1.6%; P < 0.001) and invasive MV (4.3% vs. 1.7%; P < 0.001) were significantly greater in patients with preexisting CVRFs or CVDs. In-hospital mortality (12.9% vs. 3.1%; P < 0.001) was significantly higher in patients with preexisting CVRFs or CVDs. Among the CVRFs, diabetes mellitus and hypertension were associated with increased requirement of intensive care and invasive MV and in-hospital death. Among the known CVDs, coronary artery disease and congestive heart failure were associated with invasive MV and in-hospital death. In multivariate analysis, preexisting CVRFs or CVDs (odds ratio [OR], 1.79; 95% confidence interval [CI], 1.07-3.01; P = 0.027) were independent predictors of in-hospital death after adjusting for confounding variables. Among individual preexisting CVRF or CVD components, diabetes mellitus (OR, 2.43; 95% CI, 1.51-3.90; P < 0.001) and congestive heart failure (OR, 2.43; 95% CI, 1.06-5.87; P = 0.049) were independent predictors of in-hospital death.

CONCLUSION

Based on the findings of this study, the patients with confirmed COVID-19 with preexisting CVRFs or CVDs had worse clinical outcomes. Caution is required in dealing with these patients at triage.

2021 Korean Society of Myocardial Infarction Expert Consensus Document on Revascularization for Acute Myocardial Infarction

Acute myocardial infarction (AMI) is a fatal manifestation of ischemic heart disease and remains a major public health concern worldwide despite advances in its diagnosis and management. The characteristics of patients with AMI, as well as its disease patterns, have gradually changed over time in Korea, and the outcomes of revascularization have improved dramatically. Several characteristics associated with the revascularization of Korean patients differ from those of patients in other countries. The sophisticated state of AMI revascularization in Korea has led to the need for a Korean expert consensus. The Task Force on Expert Consensus Document of the Korean Society of Myocardial Infarction has comprehensively reviewed the outcomes of large clinical trials and current practical guidelines, as well as studies on Korean patients with AMI. Based on these comprehensive reviews, the members of the task force summarize the major guidelines and recent publications, and propose an expert consensus for revascularization in patients with AMI.

The Implication of Cardiac Injury Score on In-hospital Mortality of Coronavirus Disease 2019

BACKGROUNDS

The severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) has spread worldwide. Cardiac injury after SARS-CoV-2 infection is a major concern. The present study investigated impact of the biomarkers indicating cardiac injury in coronavirus disease 2019 (COVID-19) on patients' outcomes.

METHODS

This study enrolled patients who were confirmed to have COVID-19 and admitted at a tertiary university referral hospital between February 19, 2020 and March 15, 2020. Cardiac injury was defined as an abnormality in one of the following result markers: 1) myocardial damage marker (creatine kinase-MB or troponin-I), 2) heart failure marker (N-terminal-pro B-type natriuretic peptide), and 3) electrical abnormality marker (electrocardiography). The relationship between each cardiac injury marker and mortality was evaluated. Survival analysis of mortality according to the scoring by numbers of cardiac injury markers was also performed.

RESULTS

A total of 38 patients with COVID-19 were enrolled. Twenty-two patients (57.9%) had at least one of cardiac injury markers. The patients with cardiac injuries were older (69.6 ± 14.9 vs. 58.6 ± 13.9 years old, P = 0.026), and were more male (59.1% vs. 18.8%, P = 0.013). They showed lower initial oxygen saturation (92.8 vs. 97.1%, P = 0.002) and a trend toward higher mortality (27.3 vs. 6.3%, P = 0.099). The increased number of cardiac injury markers was significantly related to a higher incidence of in-hospital mortality which was also evidenced by Kaplan-Meier survival analysis (P = 0.008).

CONCLUSION

The increased number of cardiac injury markers is related to in-hospital mortality in patients with COVID-19.

Updates of Cardiovascular Manifestations in COVID-19: Korean Experience to Broaden Worldwide Perspectives

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread worldwide. Not just respiratory complications such as pneumonia and acute respiratory distress syndrome, cardiac manifestations have drawn attention due to the increased risk of mortality and morbidity related to SARS-CoV-2 infections. The mechanisms of the cardiac injury related to SARS-CoV-2 infections have been direct cardiac injury caused by angiotensin converting enzyme 2, hypoxemia, microvascular damage, and a systemic inflammatory response. Stress induced cardiomyopathy in a critically ill condition and acute coronary syndrome due to a vulnerable plaque rupture with coagulopathy can finally lead to acute heart failure with further cardiac manifestations. When dealing with the highly contagious viral disease-related cardiac manifestations, we should carefully apply the diagnostic and therapeutic methods to achieve the best therapeutic results without adding any risk of disease transmission.

Long-term Patient Prognostication by Coronary Flow Reserve and Index of Microcirculatory Resistance: International Registry of Comprehensive Physiologic Assessment

BACKGROUND AND OBJECTIVES

Recent guideline recommends evaluation using of coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) in patients with functionally insignificant stenosis. We evaluated clinical implications of CFR and IMR in patients with high fractional flow reserve (FFR) and deferred revascularization.

METHODS

A total of 867 patients (1,152 vessels) consigned to deferred revascularization who underwent comprehensive physiologic assessments were enrolled. Patients with high FFR (>0.80) were categorized by CFR (≤2) and IMR (≥23 U). Clinical outcome was assessed by patient-oriented composite outcome (POCO), a composite of any death, myocardial infarction (MI), and revascularization at 5 years.

RESULTS

Patients with low CFR (≤2) showed significantly greater risk of POCO than those with high CFR (>2) in both high-FFR (p=0.024) and low-FFR (p=0.034) groups. In patients with high FFR, those with low CFR and high IMR (overt microvascular disease) displayed the greatest risk of POCO overall (p=0.015), surpassing those with high CFR and low IMR (HR, 2.873; 95% CI, 1.476-5.594; p=0.002) and showing significantly greater risk of cardiac death or MI (HR, 5.662; 95% CI, 1.984-16.154; p=0.001). Overt microvascular disease was independently associated with POCO in the high-FFR population (HR, 2.282; 95% CI, 1.176-4.429; p=0.015).

CONCLUSION

Among patients with deferred revascularization, those with low CFR showed significantly greater risk of POCO than those with high CFR, regardless of FFR. In patients with high FFR, those with overt microvascular disease showed significantly greater risk of POCO and cardiac death or MI at 5-year, compared with the others.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03690713.

The Current Status of Intervention for Intermediate Coronary Stenosis in the Korean Percutaneous Coronary Intervention (K-PCI) Registry

BACKGROUND AND OBJECTIVES

Intermediate coronary lesion that can be under- or over-estimated by visual estimation frequently results in stenting of functionally nonsignificant lesions or deferral of percutaneous coronary intervention (PCI) of significant lesions inappropriately. We evaluated current status of PCI for intermediate lesions from a standardized database in Korea.

METHODS

We analyzed the Korean percutaneous coronary intervention (K-PCI) registry data which collected a standardized PCI database of the participating hospitals throughout the country from January 1, 2014, through December 31, 2014. Intermediate lesion was defined as a luminal narrowing between 50% and 70% by visual estimation and then compared whether the invasive physiologic or imaging study was performed or not.

RESULTS

Physiology-guided PCI for intermediate lesions was performed in 16.8% for left anterior descending artery (LAD), 9.8% for left circumflex artery (LCX), 13.2% for right coronary artery (RCA). PCI was more frequently performed using intravascular ultrasound (IVUS) than using fractional flow reserve (FFR) for coronary artery segments (27.7% vs. 13.9% for LAD, 32.9% vs. 8.1% for LCX, and 33.8% vs. 10.8% for RCA). In accordance with or without FFR, PCI for intermediate lesions was more frequently performed in the hospitals with available FFR device than without FFR, especially in left main artery (LM), proximal LAD lesion (40.9% vs. 5.9% for LM, 24.6% vs 7.6% for proximal LAD).

CONCLUSIONS

These data provide the current PCI practice pattern with the use of FFR and IVUS in intermediate lesion. More common use of FFR for intermediate lesion should be encouraged.

Influence of Local Myocardial Infarction on Endothelial Function, Neointimal Progression, and Inflammation in Target and Non-Target Vascular Territories in a Porcine Model of Acute Myocardial Infarction

BACKGROUND

Patients with acute myocardial infarction (AMI) have worse clinical outcomes than those with stable coronary artery disease despite revascularization. Non-culprit lesions of AMI also involve more adverse cardiovascular events. This study aimed to investigate the influence of AMI on endothelial function, neointimal progression, and inflammation in target and non-target vessels.

METHODS

In castrated male pigs, AMI was induced by balloon occlusion and reperfusion into the left anterior descending artery (LAD). Everolimus-eluting stents (EES) were implanted in the LAD and left circumflex (LCX) artery 2 days after AMI induction. In the control group, EES were implanted in the LAD and LCX in a similar fashion without AMI induction. Endothelial function was assessed using acetylcholine infusion before enrollment, after the AMI or sham operation, and at 1 month follow-up. A histological examination was conducted 1 month after stenting.

RESULTS

A total of 10 pigs implanted with 20 EES in the LAD and LCX were included. Significant paradoxical vasoconstriction was assessed after acetylcholine challenge in the AMI group compared with the control group. In the histologic analysis, the AMI group showed a larger neointimal area and larger area of stenosis than the control group after EES implantation. Peri-strut inflammation and fibrin formation were significant in the AMI group without differences in injury score. The non-target vessel of the AMI also showed similar findings to the target vessel compared with the control group.

CONCLUSION

In the pig model, AMI events induced endothelial dysfunction, inflammation, and neointimal progression in the target and non-target vessels.

Functional Approach for Coronary Artery Disease: Filling the Gap Between Evidence and Practice

The presence of myocardial ischemia is the most important prognostic factor in patients with coronary artery disease, and ischemia-directed revascularization has been a standard of care. Fractional flow reserve (FFR) is an invasive method used to detect the functionally significant epicardial coronary stenosis, and FFR-guided revascularization strategy has been proven to be superior to angiography-guided strategy. Recently, a hyperemia-free index, instantaneous wave free ratio (iFR), was developed and showed its non-inferiority for clinical outcomes compared with FFR-guided strategy. While evidence supporting the benefit of pressure wire assessment exists, there remain several unresolved issues, such as the mechanism of discordance between resting and hyperemic physiologic indices, clinical outcomes of patient/lesions with discordant results among the physiologic indices, role of physiologic indices beyond per-vessel decision tool, and the role of microvascular dysfunction in patient prognosis. The current article will review the recent studies performed to address these questions.

Plaque Characteristics and Ruptured Plaque Location according to Lesion Geometry in Culprit Lesions of ST-Segment Elevation Myocardial Infarction

Background and Objectives

The correlations between plaque characteristics and plaque rupture location according to segmental lesion analysis have not been well defined. The aim of this study was to assess those characteristics of ST-segment elevation myocardial infarction (STEMI) culprit lesions according to segmental lesion geometry using virtual histology intravascular ultrasound (VH-IVUS).

Methods

Sixty single discrete lesions found in the left anterior descending (LAD) coronary arteries of 60 patients with STEMI were included. Each lesion was divided into 3 segments based on lumen area (LA) index, calculated by dividing the lesion LA by the reference LA.

Results

Among the 3 segments, the mid-segment showed the highest proportion of necrotic core (NC; proximal, mid-, and distal segments: 20.9±11.8%, 22.7±11.3%, and 17.5±11.2%, respectively, p=0.044). VH-IVUS-derived thin-cap fibroatheroma (VH-TCFA) was also more frequently found in the mid-segment than in proximal and distal segments (36.7%, 58.3%, and 16.7%, p<0.001). The mid-segment also showed the highest prevalence of plaque rupture (45.0%, 78.3% and 11.7%, p<0.001) and thrombus (61.7%, 95.0%, and 41.7%, p<0.001) compared to proximal or distal segments. When the lesions were divided into 2 groups according to the median value (4.0 mm²) of minimum lumen area (MLA), plaque rupture at the distal segment was observed only in high MLA lesions (23.3% vs. 0.0%, p=0.011).

Conclusion

Analysis of longitudinal lesion geometry using the LA index can be useful in evaluating plaque vulnerability and the incidence of plaque rupture and thrombus in STEMI patients.

Bioresorbable Vascular Scaffold Korean Expert Panel Report

Bioresorbable vascular scaffold (BRS) is an innovative device that provides structural support and drug release to prevent early recoil or restenosis, and then degrades into nontoxic compounds to avoid late complications related with metallic drug-eluting stents (DESs). BRS has several putative advantages. However, recent randomized trials and registry studies raised clinical concerns about the safety and efficacy of first generation BRS. In addition, the general guidance for the optimal practice with BRS has not been suggested due to limited long-term clinical data in Korea. To address the safety and efficacy of BRS, we reviewed the clinical evidence of BRS implantation, and suggested the appropriate criteria for patient and lesion selection, scaffold implantation technique, and management.

Clinical Outcomes in Patients with Deferred Coronary Lesions according to Disease Severity Assessed by Fractional Flow Reserve

Data on the clinical outcomes in deferred coronary lesions according to functional severity have been limited. This study evaluated the clinical outcomes of deferred lesions according to fractional flow reserve (FFR) grade using Korean FFR registry data. Among 1,294 patients and 1,628 lesions in Korean FFR registry, 665 patients with 781 deferred lesions were included in this study. All participants were consecutively categorized into 4 groups according to FFR; group 1: ≥ 0.96 (n = 56), group 2: 0.86-0.95 (n = 330), group 3: 0.81-0.85 (n = 170), and group 4: ≤ 0.80 (n = 99). Primary endpoint was major adverse cardiac events (MACE), a composite of all-cause death, myocardial infarction, and target vessel revascularization. The median follow-up period was 2.1 years. During follow-up, the incidence of MACE in groups 1-4 was 1.8%, 7.6%, 8.8%, and 13.1%, respectively. Compared to group 1, the cumulative rate by Kaplan-Meier analysis of MACE was not different for groups 2 and 3. However, group 4 had higher cumulative rate of MACE compared to group 1 (log-rank P = 0.013). In the multivariate Cox hazard models, only FFR (hazard ratio [HR], 0.95; P = 0.005) was independently associated with MACE among all participants. In contrast, previous history of percutaneous coronary intervention (HR, 2.37; P = 0.023) and diagnosis of acute coronary syndrome (ACS) (HR, 2.35; P = 0.015), but not FFR, were independent predictors for MACE in subjects with non-ischemic (FFR ≥ 0.81) deferred coronary lesions. Compared to subjects with ischemic deferred lesions, clinical outcomes in subjects with non-ischemic deferred lesions according to functional severity are favorable. However, longer-term follow-up may be necessary.

Process development for recovery of vanadium and nickel from an industrial solid waste by a leaching-solvent extraction technique

A process for recovering V(V) and Ni(II) from an industrial solid waste using sulfuric acid leaching, solvent extraction, precipitation and crystallization has been developed. The leaching parameters investigated were time, temperature and H2SO4 concentration. To quantify the linear and interaction coefficients a 2(3) full factorial experimental design was used. Regression equations for the extraction of V(V) and Ni(II) were determined and the adequacy of these equations was tested by Student's t-Test. More than 98% of both V(V) and Ni(II) were extracted in 90 min using 1.35 M H2SO4 at 40 °C. In addition, solvent extraction of V(V) with LIX 84-I in kerosene from the acidic leach liquor bearing 10.922 g/L V(V) and 18.871 g/L of Ni(II) was investigated. V(V) was extracted selectively using 40% LIX 84-I followed by stripping with NH4OH solution. McCabe-Thiele plots at O:A = 2:3 with 40% LIX 84-I and O:A = 3:1 with 15% (v/v) NH4OH showed two and three theoretical stages are needed for quantitative extraction and stripping of V(V), respectively. Ni(II) was selectively recovered from the V(V) free raffinate by adding ammonium oxalate at 60 °C. The purity of different products such as ammonium vanadate, nickel oxalate and nickel oxide obtained during the processes were analyzed and confirmed from the XRD studies.

Clinical Outcomes in Patients with Intermediate Coronary Stenoses: MINIATURE Investigators (Korea MultIceNter TrIal on Long-Term Clinical Outcome According to the Plaque Burden and Treatment Strategy in Lesions with MinimUm Lumen ARea lEss Than 4 mm(2) Using Intravascular Ultrasound)

Background and Objectives

We evaluated the two-year clinical outcomes in patients with angiographically intermediate lesions according to the plaque burden and treatment strategy.

Subjects and Methods

We prospectively enrolled patients with angiographically intermediate lesions (diameter stenosis 30-70%) with an intravascular ultrasound (IVUS) minimum lumen area (MLA) <4 mm² with 50-70% plaque burden of 16 Korean percutaneous coronary intervention centers. Patients were divided into medical therapy group (n=85) and zotarolimus-eluting stent group (ZES; Resolute) group (n=74). We evaluated the incidences of two-year major adverse cardiovascular events (MACE).

Results

A two-year clinical follow-up was completed in 143 patients and MACE occurred in 12 patients. There were no significant differences in the incidences of death (1.3% vs. 3.0%, p=0.471), target vessel-related non-fatal myocardial infarction (0.0% vs. 0.0%, p=1.000) and target vessel revascularizations (7.8% vs. 4.5%, p=0.425) between medical and ZES groups. Independent predictors of two-year MACE included acute myocardial infarction {odds ratio (OR)=2.87; 95% confidence interval (CI) 1.43-6.12, p=0.014}, diabetes mellitus (OR=2.46; 95% CI 1.24-5.56, p=0.028) and non-statin therapy (OR=2.32; 95% CI 1.18-5.24, p=0.034).

Conclusion

Medical therapy shows comparable results with ZES, and myocardial infarction, diabetes mellitus and non-statin therapy were associated with the occurrence of two-year MACE in patients with intermediate lesion with IVUS MLA <4 mm² with 50-70% of plaque burden.

Acute Stent Thrombosis and Heparin Induced Thrombocytopenia in a Patient With ST-Segment Elevation Myocardial Infarction

Heparin is an essential drug in the treatment of acute coronary syndrome and it is used during percutaneous coronary intervention (PCI). Heparin-induced thrombocytopenia (HIT), albeit a serious complication of heparin therapy characterized by thrombocytopenia and high risk for venous and arterial thrombosis, has rarely been previously reported during PCI. We report a case of an acute stent thrombosis due to an unusual cause, HIT during primary PCI, in a patient with acute myocardial infarction.

Clinical and functional correlates of early microvascular dysfunction after heart transplantation

BACKGROUND

Microvascular dysfunction is emerging as a strong predictor of outcome in heart transplant recipients. At this time, the determinants and consequences of early microvascular dysfunction are not well established. The objective of the study was to determine the risk factors and functional correlates associated with early microvascular dysfunction in heart transplant recipients.

METHODS AND RESULTS

Sixty-three heart transplant recipients who had coronary physiology assessment, right heart catheterization, and echocardiography performed at the time of their first annual evaluation were included in the study. Microvascular dysfunction was assessed using the recently described index of microcirculatory resistance. The presence of microvascular dysfunction, predefined by an index of microcirculatory resistance >20, was observed in 46% of patients at 1 year. A history of acute rejection and undersized donor hearts were associated with microvascular dysfunction at 1 year, with odds ratio of 4.0 (1.3-12.8) and 3.6 (1.2-11.1), respectively. Patients with microvascular dysfunction had lower cardiac index (3.1±0.7 versus 3.5±0.7 L/min per m(2); P=0.02) and mild graft dysfunction measured by echocardiography-derived left and right myocardial performance indices ([0.54±0.09 versus 0.43±0.09; P<0.01] and [0.47±0.14 versus 0.32±0.05; P<0.01], respectively). Microvascular dysfunction was also associated with a higher likelihood of death, graft failure, or allograft vasculopathy at 5 years after transplant (hazard ratio, 2.52 [95% CI, 1.04-5.91]).

CONCLUSIONS

A history of acute rejection during the first year and smaller donor hearts were identified as risk factors for early microvascular dysfunction. Microvascular dysfunction assessed using index of microcirculatory resistances at 1 year was also associated with worse graft function and possibly worse clinical outcomes.

Isolated acute cellular rejection of the liver after simultaneous liver and kidney transplantation: a case report

Simultaneous liver and kidney transplantation (SLKT) is now considered the treatment of choice for patients with concurrent end-stage liver and kidney diseases. Even though the early postoperative mortality rate following SLKT is reported to be high compared to that of liver transplantation alone, the liver graft from the same donor has been argued to induce better kidney graft acceptance as evidenced by a low rate of acute renal rejection episodes. There have been many reports of a low incidence of acute renal rejection following SLKT; however, only a few cases were proven by simultaneous biopsies. The authors experienced a case of biopsy-proven isolated acute cellular rejection of the liver graft following SLKT.

Analysis of air pollution in two major Korean cities: trends, seasonal variations, daily 1-hour maximum versus other hour-based concentrations, and standard exceedances

This study considers the characteristics of carbon monoxide (CO), nitrogen dioxide (NO(2)), ozone (O(3)) and sulfur dioxide (SO(2)) in two major South Korean cities, including the capital city of Seoul, over a time period of 7-8 years. Changes in the annual mean and percentiles of the daily 1-h maximum and other hour-based concentrations varied according to the compound and city type. Seasonal variations varied according to the compound, yet not with the city type. Both Seoul and Taegu exhibited lower O(3) concentrations in July compared to other summer months. There was a high degree of correlation between the daily 1- and 8-h maximum or daily mean concentrations of all compounds in both cities, with an R(2) of 0.66-0.90 at p<0.0001. It was indicated that for CO and O(3), the 8-h standard was more stringent than the 1-h standard, while for NO(2) and SO(2), the 1-h standard was more stringent than the 24-h standard. The correlation coefficients between the daily 1-h maximum and daily mean concentrations decreased as the maximum concentration values of NO(2), O(3 ), and SO(2) increased in the two cities. For all the target compounds, Seoul recorded a substantially higher frequency of days with concentrations above the relevant 1-, 8-, and 24-h standards compared to Taegu.

Characteristics of urban ground-level ozone in Korea

This study considers the characteristics of ground-level ozone (O3) in five Korean cities over a time period of 6-8 years. The focus of this study is daily maximum 1-hr and 8-hr concentrations. For all the study cities in the period examined, the mean and most of the percentiles (5, 10, 25, 50, 75, 90, and 95) for the daily maximum 1-hr and 8-hr concentrations showed increasing trends, although not all trends were statistically significant. The daily maximum 1-hr and 8-hr concentrations slowly increased during late winter, and peaks were attained during the summer season (from May to September). All the selected cities exhibited a high degree of correlation between their daily maximum 8-hr and 1-hr concentrations. The daily maximum 8-hr concentrations, which were climatologically equivalent to the Korean 1 hr/100 parts per billion (ppb) standard, were higher than the current 8 hr/60 ppb by a difference of 8-16 ppb. Compared with other cities in Korea, Seoul recorded a substantially higher frequency of days and hours with concentrations above 1 hr/100 ppb, and a higher frequency of days with concentrations above 8 hr/60 ppb and 8 hr/80 ppb. Seoul also recorded a substantially higher frequency of hours with concentrations above 1 hr/100 ppb than days with concentrations above 1 hr/100 ppb, implying that on some days severe exceedances persisted for more than one hour per day. During multiple-day episodes a North Pacific High dominated Korea, which is quite typical in Korea during the summer season.

Reduced expression of tissue inhibitor of metalloproteinase in nodal metastasis of stomach cancer

The matrix metalloproteinases (MMPs) have been associated with tumor cell invasion and metastasis of human cancers by mediating the degradation of extracellular matrix components. Therefore, these enzymes and their inhibitor (TIMP-2) constitute promising targets in the development of anticancer therapies. In order to investigate the correlation between expressions of TIMP-2, MMPs and clinical outcome, immunohistochemical staining of MMP-2, MMP-9, and TIMP-2 were performed on paraffin-embedded tissue sections of 15 early gastric cancers (EGC) and 15 advanced gastric carcinomas (AGC) without nodal metastasis and 15 AGC with nodal metastasis (AGCn+). MMP-2 and MMP-9 were expressed in neoplastic cell plasma membrane in 83.3% and 88% of cases of AGC, respectively with inter-tumoral variability of staining intensity. MMP-2 and MMP-9 staining were not correlated with presence of nodal metastasis or degree of invasion depth at the time of diagnosis (p>0.05). The immunoreactivity of TIMP-2 was detected in the peri-tumoral stroma. Residual benign stomach tissue showed no or weak immunoreactivity for TIMP-2 staining. Among AGC, neoplasms with diffuse and strong TIMP-2 staining have less frequent metastasis (28.6%) than cases with focal and weak (68.8%) (p<0.05). Early gastric cancer revealed diffuse and strong TIMP-2 expressions. We conclude that clinical outcome such as depth of invasion or metastasis is more closely related to the expression of TIMP-2 than the corresponding MMPs.