Cardiac Protection Mechanism and Clinical Application of Dexmedetomidine / 中国医学科学院学报

Dexmedetomidine is an α2 adrenoceptor agonist and has cardioprotective effect,the mechanism of which is being studied.Increasing studies have proved the clinical value of dexmedetomidine in reducing postoperative complications and improving the prognosis of patients.Therefore,this review summarizes the cardiac protection mechanism of dexmedetomidine based on the existing studies and expounds the application of dexmedetomidine in the perioperative period of cardiovascular surgery.

Value of Non-invasive Electrocardiologic Examination in Prediction of Sudden Cardiac Death / 中国医学科学院学报

Sudden cardiac death(SCD),a serious public health problem facing China and the world,causes heavy social burden.It is reported that SCD accounts for 15%-20% of all the deaths and the proportion of SCD patients with non-cardiac disease is as high as 50%.Finding effective predictors to identify SCD early is particularly important for clinical practice.To date,non-invasive electrocardiologic examination has been the first choice for predicting the risks of fatal ventricular arrhythmias and SCD because of its safety and feasibility.This review summarizes the available relevant studies to expound the value of non-invasive electrocardiologic examination and indicators in predicting SCD.

Progress in Anticoagulation of Calf Muscle Venous Thrombosis / 中国医学科学院学报

With the wide application of vascular Doppler ultrasound as well as the improvement of instrument precision and personnel operation practice,calf muscular venous thrombosis(CMVT)has been more and more frequently diagnosed among patients,becoming a common clinical disease.However,it is controversial about the anticoagulant therapy for CMVT patients.In this article,we summarize the current research progress of anticoagulation therapy,aiming to provide reference for the treatment of CMVT.

Value of cardiopulmonary exercise test in assessment of cardiac function of patients with pulmonary hypertension / 中华心血管病杂志

<p><b>OBJECTIVE</b>To explore the role of peak oxygen consumption in assessment of heart function of patients with pulmonary hypertension.</p><p><b>METHODS</b>From September 2010 to April 2012, 101 patients [29 male, mean age: (32.6 ± 11.4 )years] with pulmonary hypertension diagnosis by right heart catheterization were enrolled. Correlations among peak oxygen consumption, New York Heart Association (NYHA) class, NT-proBNP, 6 minute walking distance (6MWD) and cardiac index are analyzed.</p><p><b>RESULTS</b>There were 44 cases with NYHA class II (43.6%), 49 cases with NYHA class III (48.5%), mean 6MWD was (421 ± 91 )m, NT-proBNP was (1262 ± 816) ng/L, pulmonary vascular resistance was (1031 ± 582) dyn·s(-1)·cm(-5), CI was (3.5 ± 2.3) L·min(-1)·m(-2), peak oxygen consumption was( 13.8 ± 4.1)ml·min(-1)·kg(-1). 6MWD, pulmonary vascular resistance and peak oxygen consumption were related to CI (r = 0.299, -0.541, 0.341, respectively, all P < 0.05), but NYHA class and NT-proBNP were not correlated to CI. Multiple regression analysis demonstrated that peak oxygen consumption (B = 0.135, P = 0.004) but not 6MWD was correlated with CI after adjusting age, sex and pulmonary vascular resistance. ROC analysis found that the sensitivity and specificity using peak oxygen consumption <15.2 ml·min(-1)·kg(-1) as a cut-off value was 92.6% and 57.5%, respectively, for diagnosing severe heart dysfunction.</p><p><b>CONCLUSIONS</b>The correlation between peak oxygen consumption and CI is better than that of NYHA class, 6MWD, and NT-proBNP with CI. Peak oxygen consumption less than 15.2 ml·min(-1)·kg(-1) could be used to detect reduced CI in patients with pulmonary hypertension.</p>

Acute responses to inhalation of Iloprost in patients with pulmonary hypertension / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Iloprost has been used to test acute pulmonary vasoreactivity in idiopathic pulmonary arterial hypertension (PAH). We aimed to investigate the acute hemodynamic and oxygenation responses and tolerability to 20 µg aerosolized Iloprost in Chinese patients with pulmonary hypertension.</p><p><b>METHODS</b>Between March 2005 and May 2010, 212 pulmonary hypertension patients inhaled a single dose of 20 µg Iloprost over 10 - 15 minutes for vasoreactivity testing. The acute hemodynamic and oxygenation responses and adverse events were recorded.</p><p><b>RESULTS</b>Iloprost decreased total pulmonary resistance ((1747 ± 918) dyn×s×cm(-5) vs. (1581 ± 937) dyn×s×cm(-5), P < 0.001), increased stroke volume ((45.0 ± 22.1) ml vs. (47.0 ± 24.2) ml, P = 0.002), and cardiac output ((3.7 ± 1.7) L/ml vs. (3.9 ± 1.9) L/min, P = 0.009). Heart rate and systemic vascular resistance remained stable during inhalation. However, systemic arterial blood oxygen saturation fell slightly ((91.0 ± 6.8)% vs. (90.3 ± 6.7)%, P = 0.002). Pulmonary and systemic arterial blood pressures declined within 1 - 3 minutes after inhalation initiation and reached their lowest levels within 10 - 15 minutes. Idiopathic PAH responded more favorably than pulmonary hypertension due to other causes (P £0.001) and patients with less severe pulmonary hypertension have better responses to Iloprost. No adverse events requiring medical care or leading to termination of inhalation occurred.</p><p><b>CONCLUSIONS</b>Inhalation of 20 µg Iloprost showed potent and selective pulmonary hemodynamic effects and was well tolerated in the Chinese pulmonary hypertension patients. Patients with idiopathic PAH and less severe pulmonary hypertension responded more favorably to inhalation of Iloprost.</p>

Clinical analysis of 150 patients with idiopathic pulmonary arterial hypertension / 中华心血管病杂志

<p><b>OBJECTIVE</b>To explore the demographic characteristics and clinical features of patients with idiopathic pulmonary arterial hypertension (IPAH) in China.</p><p><b>METHODS</b>Between March 2007 and September 2010, IPAH diagnosis was confirmed by right heart catheterization in 150 adult patients from 31 clinical centers in China. Clinical and hemodynamic data were analyzed and patients were divided into WHO functional class I/II and WHO functional class III/IV group.</p><p><b>RESULTS</b>The mean age of 150 patients were 36 ± 13 years with female patient/male patient ratio of 2:1, and mean BMI was (21.3 ± 3.5) kg/m(2). Fatigue (n = 123, 82.0%) and dyspnea (n = 112, 74.7%) are the most common symptoms. Accentuated pulmonic second sound (P(2)) was detected in 92.0% (n = 138) of patients during physical examination, which was also the most common sign. About 49.0% (n = 73) patients were WHO functional class I/II patients and 46.0% (n = 68) patients were WHO functional class III/IV patients. Six minutes walking distance (6MWD) and Borg dyspnea score was (337 ± 101) m and 2.0 (2.0, 4.0), respectively. Right ventricular hypertrophy was suggested by ECG in 93.1% (n = 140) patients. Right atrial pressure was (10 ± 6) mm Hg, mean pulmonary artery pressure was (61 ± 16) mm Hg, cardiac index was (2.3 ± 0.8) L×min(-1)×m(-2) and pulmonary vascular resistance (1484 ± 699) dyn×s(-1)×cm(-5) in this cohort. 6 MWD (305 m ± 89 m vs. 377 m ± 88 m) was significantly shorter while Borg dyspnea score [3.0 (3.0, 5.0) vs. 2.0 (2.0, 3.0)] was significantly higher in WHO functional class III/IV patients than in WHO functional class I/II patients. Similarly hemodynamic parameters were also worse in WHO functional class III/IV patients than in WHO functional class I/II patients (all P < 0.05).</p><p><b>CONCLUSION</b>Idiopathic pulmonary arterial hypertension patients in this cohort affect mostly young adults, dominated by female gender and lower body mass index. Fatigue and dyspnea are the most common symptoms and accentuated pulmonic second sound (P(2)) is the most common sign. IPAH patients are often displaying severe functional and hemodynamic disturbance at first visit to hospitals. Dyspnea and hemodynamic impairment are related to 6MWD and WHO functional class.</p>

Multiple dimensions of cardiopulmonary dyspnea / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The current theory of dyspnea perception presumes a multidimensional conception of dyspnea. However, its validity in patients with cardiopulmonary dyspnea has not been investigated.</p><p><b>METHODS</b>A respiratory symptom checklist incorporating spontaneously reported descriptors of sensory experiences of breathing discomfort, affective aspects, and behavioral items was administered to 396 patients with asthma, chronic obstructive pulmonary disease (COPD), diffuse parenchymal lung disease, pulmonary vascular disease, chronic heart failure, and medically unexplained dyspnea. Symptom factors measuring different qualitative components of dyspnea were derived by a principal component analysis. The separation of patient groups was achieved by a variance analysis on symptom factors.</p><p><b>RESULTS</b>Seven factors appeared to measure three dimensions of dyspnea: sensory (difficulty breathing and phase of respiration, depth and frequency of breathing, urge to breathe, wheeze), affective (chest tightness, anxiety), and behavioral (refraining from physical activity) dimensions. Difficulty breathing and phase of respiration occurred more often in COPD, followed by asthma (R(2) = 0.12). Urge to breathe was unique for patients with medically unexplained dyspnea (R(2) = 0.12). Wheeze occurred most frequently in asthma, followed by COPD and heart failure (R(2) = 0.17). Chest tightness was specifically linked to medically unexplained dyspnea and asthma (R(2) = 0.04). Anxiety characterized medically unexplained dyspnea (R(2) = 0.08). Refraining from physical activity appeared more often in heart failure, pulmonary vascular disease, and COPD (R(2) = 0.15).</p><p><b>CONCLUSIONS</b>Three dimensions with seven qualitative components of dyspnea appeared in cardiopulmonary disease and the components under each dimension allowed separation of different patient groups. These findings may serve as a validation on the multiple dimensions of cardiopulmonary dyspnea.</p>

Hemodynamic effects and safety of pulmonary angiography in Chinese patients with pulmonary hypertension / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Pulmonary angiography is widely performed in pulmonary hypertension patients, but its immediate effects on right heart hemodynamics and safety are not well known. The objective of this study was to investigate the right heart hemodynamic effects and safety of pulmonary angiography in Chinese patients with pulmonary hypertension.</p><p><b>METHODS</b>Between January 2008 and June 2009, pulmonary hypertension patients undergoing pulmonary angiography were consecutively enrolled. Pulmonary angiography was performed during breath-holding after deep breathing. The baseline clinical data, hemodynamic measurements before and after pulmonary angiography and complications occurring within 48 hours after angiography were recorded.</p><p><b>RESULTS</b>Ninety-five patients were included. All received non-ionic contrast medium with a volume of (75.7 ± 29.8) ml. Angiography reduced heart rate in patients with baseline mean pulmonary arterial pressure ≥ 60 mmHg (change of heart rate: (-3.1 ± 7.0) beats/min, P = 0.005), increased mean right atrial pressure, diastolic and end-diastolic right ventricular pressure in patients with baseline mean pulmonary arterial pressure < 60 mmHg (all P < 0.05). Patients with decreased mean pulmonary arterial pressure (change of mean pulmonary arterial pressure ≤ -10 mmHg) had the highest total pulmonary resistance (P = 0.009 vs. no change in mean pulmonary arterial pressure (change of mean pulmonary arterial pressure, -10 mmHg to 10 mmHg); P = 0.03 vs. increased mean pulmonary arterial pressure (change of mean pulmonary arterial pressure ≥ 10 mmHg)) and the lowest cardiac output (P = 0.018 vs. no change in mean pulmonary arterial pressure; P = 0.013 vs. increased mean pulmonary arterial pressure). There were 7 complications (7%), with 6 related to catheter and only 1 directly related to angiography. All complications were mild and no death occurred.</p><p><b>CONCLUSION</b>Pulmonary angiography has minimal effect on right heart hemodynamics and is safe in pulmonary hypertension patients.</p>

Prognostic value of echocardiographic right/left ventricular end-diastolic diameter ratio in idiopathic pulmonary arterial hypertension / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>An echocardiographic right/left ventricular end-diastolic diameter ratio (RV/LV ratio) ≥ 0.9 is an independent predictor of poor prognosis in patients with acute pulmonary embolism. Right ventricular dilation is a common characteristic of both acute pulmonary embolism and idiopathic pulmonary arterial hypertension (IPAH). However, the prognostic value of the RV/LV ratio in patients with IPAH is unknown.</p><p><b>METHODS</b>Ninety-five consecutive patients with newly diagnosed IPAH were included, 17 were re-evaluated by echocardiography after 3 - 12 months of targeted therapy. Follow-up data were obtained by telephone interviews and review of the patients' records.</p><p><b>RESULTS</b>Higher RV/LV ratios were associated with greater functional impairment. The RV/LV ratio was positively correlated with pulmonary vascular resistance (r = 0.549, P < 0.001) and plasma N-terminal pro-brain natriuretic peptide level (r = 0.575, P < 0.001), but negatively correlated with cardiac output (r = -0.517, P < 0.001) and mixed venous oxygen saturation (r = -0.599, P < 0.001). Twenty-seven patients died during follow-up period. Sensitivity and specificity of an RV/LV ratio ≥ 0.84 for predicting death were 85.2% and 51.5%, respectively. The RV/LV ratio and body mass index were independent predictors of death by multivariate Cox analysis (P < 0.01). A baseline RV/LV ratio ≥ 0.84 or a further increase in the RV/LV ratio during targeted therapy indicated a poor prognosis (P < 0.01).</p><p><b>CONCLUSION</b>The RV/LV ratio helps to assess the severity of IPAH and may serve as an independent predictor of prognosis in patients with IPAH.</p>

18F-FDG SPECT myocardial imaging of right ventricle in patients with idiopathic pulmonary hypertension / 中华核医学杂志

ObjectiveTo investigate the value of 18F-FDG SPECT myocardial imaging in evaluating haemodynamic change,treatment outcome and prognosis for idiopathic pulmonary arterial hypertension (IPAH).MethodsAll 24 patients with IPAH underwent 18 F-FDG SPECT myocardial imaging.Right ventricle/left ventricle (RV/LV)-FDG uptake was calculated by ROI method drawing over the central areas of left and right ventricular free walls.All patients underwent right heart catheterization within 3 days after imaging studies.Mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR) were recorded.After six month pharmaceutical treatment,15 IPAH patients were re-examined with 18F-FDG SPECT myocardial imaging followed by repeated right heart catheterization within 3 days.Plasma N-terminal pro-brain naturetic peptide (NT-proBNP) and endothelin-1 ( ET-1 ) were measured in 17 patients using electrochemiluminescent immunoassay and enzyme immunoassay respectively.All patients were followed up for 12 months at least.Correlations between RV/LV-FDG uptake and mPAP and PVR were determined by simple linear regression analysis.Change of RV/LV-FDG before and after treatment was calculated using Student's t-test.Survival in groups with RV/LV FDG uptake ≥ 1.15 and RV/LV-FDG uptake ＜ 1.15 were compared using Log-rank test.ResultsSignificant correlations were found between RV/LV-FDG uptake and mPAP (r =0.562,P ＜ 0.01 ),and between RV/LV-FDG uptake and PVR ( r =0.574,P ＜ 0.01 ).There were no significant correlation between RV/LV-FDG uptake and NT-proBNP( r =0.18 1,P ＞ 0.05 ),but a significant correlation between RV/LV-FDG and ET-1 was observed (r =0.669,P ＜ 0.01 ).The RV/LV-FDG uptake in patients with positive treatment outcome ( n =6) decreased from 1.38 ± 0.52 to 0.92 ±0.26 (t =4.018,P ＜ 0.05) after 6 months treatment.In contrast,no significant change of RV/LV-FDG uptake was seen in those patients (n =9) with negative treatment outcome ( t =1.861,P ＞ 0.05 ).The mean follow-up time was (21 ±8) months.Mean survival time for the patients with RV/LV- FDG uptake ≥ 1.15was 28 months (95％ confidence interval:24-32 months),which was significantly lower than 34 months survival (95％ confidence interval:33-35 months) for the patients with RV/LV-FDG ＜ 1.15 (x2 =3.956,P ＜0.05 ).Conclusions Detection of right ventricle myocardial glucose metabolism level with 18F-FDG SPECT may be a practical method for evaluating haemodynamic change,treatment outcome and prognosis of IPAH.

Pulmonary perfusion imaging combined with Wells score and D-dimer assay for the diagnosis of acute pulmonary embolism / 中华核医学杂志

Objective To investigate the value of the Wells score and D-dimer assay in assisting pulmonary perfusion imaging (PPI) for the diagnosis of acute pulmonary embolism (APE). Methods One hundred twenty-one patients with suspected APE were studied from January, 2006 to December, 2008. All patients underwent the Wells score, the quantitative D-dimer assay, chest X-ray photography, and PPI. The diagnostic sensitivity, specificity, positive predictive value and negative predictive value of PPI with the assistance of Wells score and D-dimer assay were calculated. Results Fifty (41.3%) patients were diagnosed with APE. PPI combined with chest X-ray photography (Q/X scan) showed positive results in 49 patients. The sensitivity, specificity, positive predictive value and negative predictive value of the Q/X scan were 86.0% (43/50), 91.5% (65/71), 87.8% (43/49) and 90.3% (65/72), respectively. With assistance of Wells score >4 and D-dimer≥0. 5 mg/L, Q/X scan had a positive predictive value of 100.0% (29/29), for patients with Wells score ≤4 and D-dimer<0.5 mg/L, the negative predictive value for Q/X scan was 100.0% (41/41). Conclusion Combined with Wells score and D-dimer assay, PPI can make accurate diagnosis of APE.

Clinical features of 18 patients with isolated right sided infective endocarditis / 中华心血管病杂志

<p><b>OBJECTIVE</b>To analyze the clinical characteristics of 18 patients with isolated right sided infective endocarditis (RSIE) who hospitalized in our department between August 2005 and February 2009.</p><p><b>METHODS</b>The epidemiological and clinical data of 18 non-drug addicts with RSIE were retrospectively analyzed.</p><p><b>RESULTS</b>The incidence of RSIE accounted for 7.23% of all IE patients hospitalized in our department during the same period. Predisposing conditions were as follows: congenital heart disease (76.5%, 14/18), post operative procedures (3/18) and high dose glucocorticoids use (1/18). Fever (100%) was the most common clinical manifestation. Septic pulmonary embolism was the most prevalent complication (5/18). Staphylococci aureus (4/7) were the most common causative patho organisms, while the most common etiological organisms of left-sided and both-sided IE were Streptococci Viridans. Transthoracic echocardiography evidenced 17 cases of vegetations including 59.1% (13/22) tricuspid vegetations. There was no in-hospital death and the mean hospitalization duration was (22.0 +/- 18.9) days.</p><p><b>CONCLUSIONS</b>Congenital heart diseases, but not intravenous drug abuse, were the most prevalent predisposing factors for RSIE in this cohort. Staphylococci aureus were the most common causative organisms.</p>

The prognosis study of 108 idiopathic pulmonary arterial hypertension patients / 中华心血管病杂志

<p><b>OBJECTIVE</b>To analyze the characteristics of idiopathic pulmonary arterial hypertension (IPAH) and predict the prognosis of IPAH by Echocardiogram and Right Heart Catheterization.</p><p><b>METHODS</b>108 IPAH patients who was diagnosed as IPAH in Fuwai hospital from Jan 2003 to Jun 2007 were retrospectively analyzed and followed up to June 2008, the statistical analysis software was SPSS 13.0.</p><p><b>RESULT</b>The mean age of the 108 IPAH patients was (32.5 +/- 12.6) years, the ratio of female and male was 2.86:1, the average time from appearing symptom to diagnosis was (34.9 +/- 36.3) months, the incidence of syncope, hepatomegaly, hemoptysis and Edema of lower extremity was 32.4%, 27.8%, 15.7% and 14.8% respectively. A total of 94 patients (87.0%) were followed up for (27.6 +/- 14.7) months, forty-two patients (38.9%) died of right heart failure, the mean death time was (11.6 +/- 9.4) months after diagnosis, the survival rate of 1, 2 and 3 years was 74%, 58% and 44% respectively. These following variables could predict survival in univariate analysis: Systolic Blood Pressure (SBP) (P < 0.01, RR = 0.937), pulse Pressure (PP) (P < 0.01, RR = 0.930), left ventricular End-Diastolic Dimension (LVEDD) (P = 0.004, RR = 0.924), right ventricular End-Diastolic Dimension (RVEDD) (P = 0.029, RR = 1.045), RVEDD/LVEDD (P = 0.003, RR = 3.222), Pulmonary Arterial Systolic Pressure (PASP) measured by echocardiogram (P = 0.002, RR = 1.022), PASP (P = 0.030, RR = 1.026), mean Pulmonary Arterial Pressure (mPAP) (P = 0.031, RR = 1.037) and Pulmonary Vascular Resistance (PVR) measured by right heart catheter (P = 0.019, RR = 1.001). in multivariate analysis, PP (P < 0.01, RR = 0.923), RVEDD/LVEDD (P = 0.006, RR = 3.126) and PASP measured by Echocardiogram (P = 0.002, RR = 1.022), PASP, mPAP, PVR measured by right heart catheter (P = 0.017, RR = 1.001) were predictive.</p><p><b>CONCLUSION</b>IPAH was prone to attack young women with a poor prognosis, the diagnosis of IPAH at an early stage was difficult because of nonspecific symptom, syncope, hepatomegaly and Edema of lower extremity can predict the severity of IPAH, PVR measured by right heart catheterization, PP and PASP were independently predictive factors for IPAH.</p>

Value of radionuclide lung scintigraphy in the diagnosis and quantitative analysis of chronic thromboembolic pulmonary hypertension / 中华心血管病杂志

<p><b>OBJECTIVE</b>This study was to assess the reliability of perfusion/ventilation (Q/V) lung scintigraphy in the diagnosis and quantitative analysis of chronic thromboembolic pulmonary hypertension (CTEPH).</p><p><b>METHODS</b>A total of 78 in-patients with pulmonary hypertension who had no history of congenital heart disease, valvular disease and acute pulmonary embolism were included in this study. All patients underwent Q/V scintigraphy for detecting CTEPH. The sensitivity, specificity and accuracy of Q/V scintigraphy were defined by comparing with the results of pulmonary angiography. Percentage of Perfusion Defect score (PPDs%) was calculated in patients with CTEPH confirmed by pulmonary angiography. The correlations between PPDs% and mPAP, PPDs% and SPAP were analyzed.</p><p><b>RESULTS</b>The sensitivity, specificity and accuracy of a high-probability Q/V scintigraphy interpretation were 96.0%, 81.1% and 86.9%, respectively, compared with 100%, 69.8% and 79.5% for the combination of high- and intermediate- probability Q/V scintigraphy interpretation. PPDs% was significantly correlated with mPAP and SPAP (r = 0.538 for mPAP, P < 0.01 and r = 0.456 for SPAP, P < 0.05).</p><p><b>CONCLUSION</b>Perfusion/ventilation lung scintigraphy is a valuable technique for diagnosis and quantitative analysis of CTEPH.</p>

Changes of the proportion and mortality of pulmonary thromboembolism in hospitalized patients from 1974 to 2005 / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Pulmonary thromboembolism (PTE) has become a common disease that severely endangers people's health. This study analysed the changes in proportion and mortality of PTE in hospitalized patients to provide data for prevention and management of the disease.</p><p><b>METHODS</b>The data of 763 hospitalized patients with PTE from 1974 to 2005 in Fuwai Hospital were analysed.</p><p><b>RESULTS</b>During the 1970s, 0.27% of patients in a cardiovascular hospital had PTE (< 5 cases per year); while so far this century the proportion is 0.94% (48 to 113 per year). The mortality of hospitalized PTE patients fell from 20.00% in the 1970s to 4.10% this century. Prior to 1990, the mortality of hospitalized PTE patients was 12.50%, and in the years after 1990 only 3.40%. The difference was statistically significant (P < 0.005). People with this disease were mostly between the ages of 30 and 69 years. Men were most susceptible between the ages of 30 and 69 years, while women between the ages of 40 and 69 years. Men contracted PTE 10 years earlier than women. The mortality of male PTE patients was 4.70%, not significantly different from female patients, 5.06% (0.50 < P < 0.75). There were not any significant differences between the mortality of patients in the different age groups overall (< or = 39, 40 - 49, 50 - 59, and > or = 60 years, P > 0.1). More people contracted the disease in winter than in other seasons (P < 0.05). There was no obvious difference between the mortality in different seasons overall (0.75 < P < 0.90).</p><p><b>CONCLUSION</b>PTE is an increasingly significant disease and deserves adequate attention.</p>