Treatment and Clinical Management of Chronic Thromboembolic Pulmonary Hypertension:An Update of Literature Review

Chronic thromboembolic pulmonary hypertension(CTEPH)is a chronic,progressive,debilitating,and life-threa-tening complication of pulmonary embolism(PE).Recent technological advances have permitted various treat-ment options for the treatment of CTEPH,including surgery,angioplasty,and medical treatment,depending on the location and characteristics of lesions.Pulmonary endarterectomy(PEA)is the treatment of choice for CTEPH,as it offers excellent long-term outcomes and a high probability of recovery.Moreover,various medical and interventional therapies are currently being developed for patients with inoperable CTEPH.This review mainly summarizes the current treatment approaches of CTEPH,offering more options for specialist physicians to,thus,better manage chronic thromboembolic syndromes.

Risk Stratification and Prognosis of Pulmonary Arterial Hypertension Associated with Congenital Heart Disease

Background:Current guidelines for managing pulmonary arterial hypertension(PAH)recommend a risk strati-fication approach.However,the applicability and accuracy of these strategies for PAH associated with congenital heart disease(PAH-CHD)require further validation.This study aims to validate the reliability and predictive accuracy of a simplified stratification strategy for PAH-CHD patients over a three-year follow-up.Additionally,new prognostic variables are identified and novel risk stratification methods are developed for assessing and managing PAH-CHD patients.Methods:This retrospective study included 126 PAH-CHD patients.Clinical and biochemical variables across risk groups were assessed using Kruskal-Wallis and Fisher’s exact tests.Indepen-dent risk factors were identified using ordered logistic regression,while Kaplan-Meier and Cox proportional hazards regression analyses evaluated their impact on all-cause mortality.A new stratification model for the PAH-CHD population was constructed based on these analyses.Results:Significant survival differences across stratified risk groups were observed(p<0.001),validating the effectiveness of the simplified risk stratification method in PAH-CHD patients.Prothrombin activity was a strong independent predictor of adverse outcomes of PAH-CHD patients(Hazard ratio 0.95,p<0.001,C-index 0.70).A model combining N-terminal pro-brain natriuretic peptide,prothrombin activity,albumin,and right atrial area achieved an area under the curve of 0.89 and a C-index of 0.85.Conclusions:The simplified risk stratification method is applicable to PAH-CHD patients.Prothrombin activity is a strong independent predictor of adverse outcomes.A comprehensive risk stratification approach,incorporating both established and novel biomarkers,enhances accessibility and offers predictive efficacy during follow-up for PAH-CHD patients,comparable to established models.

Development of pulmonary hypertension remains a major hurdle to corrective surgery in Down syndrome

Down syndrome is the most common chromosomal abnormality encountered in clinical practice with 50%of them having associated congenital heart disease(CHD).Shunt lesions account for around 75%of all CHDs in Down syndrome.Down syndrome patients,especially with large shunts are particularly predisposed to early development of severe pulmonary hypertension(PH)compared with shunt lesions in general population.This necessitates timely surgical correction which remains the only viable option to prevent long term morbidity and mortality.However,despite clear recommendations,there is wide gap between actual practice and fear of underlying PH which often leads to surgical refusals in Down syndrome even when the shunt is reversible.Another peculiarity is that Down syndrome patients can develop PH even after successful correction of shunt.It is not uncommon to come across Down syndrome patients with uncorrected shunts in adulthood with irreversible PH at which stage intracardiac repair is contraindicated and the only option available is a combined heartlung transplant.However,despite the guidelines laid by authorities,the rates of cardiac transplant in adult Down syndrome remain dismal largely attributable to the high prevalence of intellectual disability in them.The index case presents a real-world scenario highlighting the impact of severe PH on treatment strategies and discrimination driven by the fear of worse outcomes in these patients.

Role of pulmonary perfusion magnetic resonance imaging for the diagnosis of pulmonary hypertension:A review

Among five types of pulmonary hypertension,chronic thromboembolic pulmonary hypertension(CTEPH)is the only curable form,but prompt and accurate diagnosis can be challenging.Computed tomography and nuclear medicine-based techniques are standard imaging modalities to non-invasively diagnose CTEPH,however these are limited by radiation exposure,subjective qualitative bias,and lack of cardiac functional assessment.This review aims to assess the methodology,diagnostic accuracy of pulmonary perfusion imaging in the current literature and discuss its advantages,limitations and future research scope.

Pulmonary arterial hypertension confirmed by right heart catheterization following COVID-19 pneumonia: A case report and review of literature

BACKGROUND Pulmonary arterial hypertension(PAH)is a disease of the arterioles resulting in an increased resistance in pulmonary circulation with associated high pressures in the pulmonary arteries,causing irreversible remodeling of the pulmonary arterial walls.Coronavirus disease 2019(COVID-19)has been associated with development of new onset PAH in the literature leading to symptoms of dyspnea,cough and fatigue that persist in spite of resolution of acute COVID-19 infection.However,the majority of these cases of COVID related PAH were diagnosed using echocardiographic data or via right heart catheterization in mechanically ventilated patients.CASE SUMMARY Our case is the first reported case of COVID related PAH diagnosed by right heart catheterization in a non-mechanically ventilated patient.Right heart catheterization has been the gold standard for diagnosis of pulmonary hypertension.Our patient had right heart catheterization four months after her initial COVID-19 infection due to persistent dyspnea.CONCLUSION This revealed new onset PAH that developed following her infection with COVID-19,an emerging sequela of the infection.

Mufangji tang ameliorates pulmonary arterial hypertension through improving vascular remodeling,inhibiting inflammatory response and oxidative stress,and inducing apoptosis

Background:Mufangji tang(MFJT)is composed of Ramulus Cinnamomi,Radix Ginseng,Cocculus orbiculatus(Linn.)DC.,and Gypsum.In clinical settings,MFJT has been effectively employed in addressing a range of respiratory disorders,notably including pulmonary arterial hypertension(PAH).However,the mechanism of action of MFJT on PAH remains unknown.Methods:In this study,a monocrotaline-induced PAH rat model was established and treated with MFJT.The therapeutic effects of MFJT on PAH rat model were evaluated.Network pharmacology was conducted to screen the possible targets for MFJT on PAH,and the molecular docking between the main active components and the core targets was carried out.The key targets identified from network pharmacology were tested.Results:Results showed significant therapeutic effects of MFJT on PAH rat model.Analysis of network pharmacology revealed several potential targets related to apoptosis,inflammation,oxidative stress,and vascular remodeling.Molecular docking showed that the key components were well docked with the core targets.Further experimental validation results that MFJT treatment induced apoptosis(downregulated Bcl-2 levels and upregulated Bax levels in lung tissue),inhibited inflammatory response and oxdative stress(decreased the levels of IL-1β,TNF-α,inducible NOS,and malondialdehyde,and increased the levels of endothelial nitric oxide synthase,nitric oxide,glutathione and superoxide dismutase),reduced the proliferation of pulmonary arterial smooth muscle cells(downregulated ET-1 andβ-catenin levels and ERK1/2 phosphorylation,increased GSK3βlevels).Conclusion:Our study revealed MFJT treatment could alleviate PAH in rats via induction of apoptosis,inhibition of inflammation and oxidative stress,and the prevention of vascular remodeling.

Intervention control of aerobic exercise in maintaining quality of life and pulmonary hypertension in hemodialysis patients

BACKGROUND Pulmonary hypertension is a serious complication in the treatment of maintenance hemodialysis patients,which seriously affects the quality of life of patients and threatens their life safety.Prevention,treatment and improvement of pulmonary hypertension are of great significance to improve the quality of life of patients.AIM To investigate the intervention and control of pedal-powered bicycle in maintaining quality of life and pulmonary hypertension in hemodialysis patients.METHODS 73 patients with maintenance hemadialysis combined with pulmonary arterial hypertension at a hemodialysis center in a certain hospital from May 2021 to May 2022 are selected.Patients are divided into two groups,37 cases in the control group(group C)and 36 cases in the intervention group(group I).Patients are divided into two groups,group C is treated with oral administration of betaglandin sodium combined with routine nursing care.Based on group C,group I conducts power cycling exercises.RESULTS After treatment,group I patients had higher muscle strength,36-Item Short Form Health Survey scores,and Kidney Disease Targets Areas scores;The 6-minute walk distance test index level was higher and the Borg score was lower;The group I had lower systolic blood pressure,greater vital capacity,higher positive emotion,lower systolic pulmonary artery pressure index level,higher arterial partial oxygen pressure level,lower pulmonary vascular resistance index level,and higher blood oxygen saturation level[158.91±11.89 vs 152.56±12.81,1795.01±603.18 vs 1907.20±574.15,24.00(22.00,29.00)vs 24.00(22.00,28.00),P<0.001].CONCLUSION Aerobic exercise combined with Western medicine treatment can effectively improve patients'pulmonary hypertension,alleviate their negative emotions,and enable them to achieve a higher level of quality of life.

Impact of diabetes mellitus on mortality in pulmonary hypertension:A systematic review and meta-analysis

BACKGROUND Pulmonary hypertension(PH)is a progressive disease characterized by endothelial dysfunction and vascular remodeling and is a leading cause of mortality worldwide.Although it is independently associated with multiple comorbidities,the impact of diabetes mellitus(DM)on mortality in patients with PH remains uncertain.To address this issue,we conducted a systematic review and meta-analysis to investigate the effect of DM on survival in patients with pulmonary hypertension.AIM To investigate the impact of diabetes mellitus on mortality in pulmonary hypertension patients.METHODS We conducted a comprehensive search of four major electronic bibliographic databases like PubMed,Google Scholar,Scopus,and Embase,and identified 106 relevant studies,out of 1561 articles,published since the year 2000 for full-text review.Fourteen retrospective and prospective cohort studies that compared survival between patients with DM and those without DM in the context of PH were deemed eligible for inclusion in our meta-analysis.The study was registered on PROSPERO with the identifier CRD42023390232.RESULTS A total of 116455 patients with PH were included in the meta-analysis,of whom 41228 suffered from DM and 75227 did not.The results of our meta-analysis indicate an elevated mortality rate among PH patients with diabetes mellitus in comparison to those without DM[odds ratio(OR)=1.40,95%CI:1.15–1.70,P=0.0006].The metaregression analysis unveiled a statistically significant negative association between mean age and effect size(coefficient=-0.036,P value=0.018).Conversely,a statistically significant positive association was detected between female proportion and effect size(coefficient=0.000,P value<0.001).CONCLUSION Our meta-analysis,which included approximately 116500 PH patients,revealed that the presence of diabetes mellitus was associated with increased odds of mortality when compared to non-diabetic patients.The metaregression analysis indicates that studies with older participants and lower proportions of females tend to exhibit smaller effect sizes.Clinically,these findings underscore the importance of incorporating diabetes status into the risk stratification of patients with PH with more aggressive monitoring and early intervention to improve prognosis potentially.

Effects of combined aerobic,resistance and inspiratory training in patients with pulmonary hypertension:A systematic review

BACKGROUND Pulmonary hypertension(PH)is a serious progressive disorder of the modern world,characterized by endothelial dysfunction and impaired vasoreactivity.Patients with PH usually present exercise intolerance from the very early stages and reduced exercise capacity.Exercise training has been shown to have beneficial effects in patients with cardiovascular comorbidities.However,data regarding the effects of combined exercise training programs in patients with PH still remains limited.AIM To investigate the effects of combined exercise training programs on exercise capacity and quality of life in patients with PH.METHODS Our search included all available randomized controlled trials(RCTs)regarding combined aerobic,resistance and inspiratory training programs in patients with PH in 4 databases(Pubmed,PEDro,Embase,CINAHL)from 2012 to 2022.Five RCTs were included in the final analysis.Functional capacity,assessed by peak VO_(2)or 6-min walking test(6MWT),as well as quality of life,assessed by the SF-36 questionnaire,were set as the primary outcomes in our study.RESULTS Peak VO_(2)was measured in 4 out of the 5 RCTs while 6MWT was measured in all RCTs.Both indices of functional capacity were significantly increased in patients with PH who underwent combined exercise training compared to the controls in all of the included RCTs(P<0.05).Quality of life was measured in 4 out of 5 RCTs.Although patients improved their quality of life in each group,however,only 2 RCTs demonstrated further improvement in patients performing combined training compared to controls.CONCLUSION By this systematic review,we have demonstrated that combined aerobic,resistance and inspiratory exercise training is safe and has beneficial effects on aerobic capacity and quality of life in patients with PH.Such exercise training regimen may be part of the therapeutic strategy of the syndrome.

Choriocarcinoma-associated pulmonary thromboembolism and pulmonary hypertension： a case report

Cases of pulmonary embolism and pulmonary artery hypertension caused by choriocarcinoma represent a rare clinical emergency. We report a case of a 25-year-old woman who presented with pulmonary embolism and hyper- tension and died soon after complete pulmonary embolectomy. A related literature review revealed that almost all of these patients had previously experienced a spontaneous abortion （average, 6 months） and were not pregnant.

Pulmonary hypertension secondary to seronegative rheumatoid arthritis overlapping antisynthetase syndrome:A case report

BACKGROUND Polyarthritis is the most frequent clinical manifestation in antisynthetase syndrome(ASS)forms of idiopathic inflammatory myositis and may be misdiagnosed as rheumatoid arthritis(RA),particularly in patients with seronegative RA(SNRA).It is unclear whether there is an overlap between ASS and RA,or if ASS sometimes mimics RA.Pulmonary hypertension(PAH)is common in connective tissue diseases(CTDs).However,published reports on CTD-PAH do not include overlapping CTDs,and its incidence and impact on patient prognosis are unclear.CASE SUMMARY We report the case of a 63-year-old woman who presented with a 3-mo history of symptom aggravation of recurrent symmetrical joint swelling and pain that had persisted for over 10 years.The patient was diagnosed with RA and interstitial lung disease.The patient repeatedly presented to the hospital’s respiratory and rhe-umatology departments with arthralgia,plus shortness of breath after activity.Relevant tests indicated that anti-CCP and RF remained negative,while anti-J0-1 and anti-Ro-52 were strongly positive.It was not until recently that we recognized that this could be an unusual case of SNRA with concurrent ASS.Joint pain was relieved after regular anti-rheumatic treatment.Chest computed tomography scans showed that pulmonary interstitial changes did not progress significantly over several years;however,they showed gradual widening of the pulmonary artery,and cardiac ultrasound indicated elevated pulmonary artery systolic pressure.The prescribed treatment of PAH was not effective in improving shortness of breath.CONCLUSION Overlap of RA and ASS may be missed.Further research is necessary to facilitate early diagnosis,effective evaluation,and prognosis.

Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension:State of the art

Chronic thromboembolic pulmonary hypertension(CTEPH)is a complex chronic disease in which pulmonary artery stenosis or obstruction caused by organized thrombus can lead to increased pulmonary artery pressure and pulmonary vascular resistance,ultimately triggering progressive right heart failure and death.Currently,its exact mechanism is not fully understood.Pulmonary endarterectomy(PEA)has immediate effects with low perioperative mortality and satisfactory prognosis in experienced expert centers for CTEPH patients with proximal lesions.Nevertheless,37%of patients are deemed unsuitable for PEA surgery due to comorbidities and other factors,and nearly half of the operated patients have residual or recurrent pulmonary hypertension.Riociguat is the only approved drug for CTEPH,although its effect is limited.Balloon pulmonary angioplasty(BPA)is a promising alternative treatment for patients with CTEPH.After more than 30 years of development and refinements,emerging evidence has confirmed its role in patients with inoperable CTEPH or residual/recurrent pulmonary hypertension,with acceptable complications and comparable longterm prognosis to PEA.This review summarizes the pathophysiology of CTEPH,BPA history and development,therapeutic principles,indications and contraindications,interventional procedures,imaging modalities,efficacy and prognosis,complications and management,bridging and hybrid therapies,ongoing clinical trials and future prospects.

Prevalence of pulmonary hypertension among children with Down syndrome:A systematic review and meta-analysis

BACKGROUND Pulmonary hypertension(PH)has serious short-and long-term consequences.PH is gaining increasing importance in high risk groups such as Down syndrome(DS)as it influences their overall survival and prognosis.Hence,there is a dire need to collate the prevalence rates of PH in order to undertake definitive measures for early diagnosis and management.AIM To determine the prevalence of PH in children with DS.METHODS The authors individually conducted a search of electronic databases manually(Cochrane library,PubMed,EMBASE,Scopus,Web of Science).Data extraction and quality control were independently performed by two reviewers and a third reviewer resolved any conflicts of opinion.The words used in the literature search were“pulmonary hypertension”and“pulmonary arterial hypertension”;“Down syndrome”and“trisomy 21”and“prevalence”.The data were analyzed by Comprehensive Meta-Analysis Software Version 2.Risk of bias assessment and STROBE checklist were used for quality assessment.RESULTS Of 1578 articles identified,17 were selected for final analysis.The pooled prevalence of PH in these studies was 25.5%.Subgroup analysis was carried out for age,gender,region,year of publication,risk of bias and etiology of PH.CONCLUSION This review highlights the increasing prevalence of PH in children with DS.It is crucial for pediatricians to be aware of this morbid disease and channel their efforts towards earlier diagnosis and successful management.Community-based studies with a larger sample size of children with DS should be carried out to better characterize the epidemiology and underlying etiology of PH in DS.

Periodontitis exacerbates pulmonary hypertension by promoting IFNγ^(+)T cell infiltration in mice

Uncovering the risk factors of pulmonary hypertension and its mechanisms is crucial for the prevention and treatment of the disease.In the current study,we showed that experimental periodontitis,which was established by ligation of molars followed by orally smearing subgingival plaques from patients with periodontitis,exacerbated hypoxia-induced pulmonary hypertension in mice.Mechanistically,periodontitis dysregulated the pulmonary microbiota by promoting ectopic colonization and enrichment of oral bacteria in the lungs,contributing to pulmonary infiltration of interferon gamma positive(IFNγ^(+))T cells and aggravating the progression of pulmonary hypertension.In addition,we identified Prevotella zoogleoformans as the critical periodontitis-associated bacterium driving the exacerbation of pulmonary hypertension by periodontitis,and the exacerbation was potently ameliorated by both cervical lymph node excision and IFNγneutralizing antibodies.Our study suggests a proof of concept that the combined prevention and treatment of periodontitis and pulmonary hypertension are necessary.

Extracorporeal membrane oxygenation as a bridging therapy for patients with thiamine deficiency-induced pulmonary arterial hypertension

Thiamine deficiency is characterized by a deficiency of thiamine(vitamin B1),lactic acidosis,pulmonary arterial hypertension(PAH),right-sided heart failure,and peripheral nerve damage.Thiamine deficiency is easily misdiagnosed and missed during clinical practice and is associated with death in severe cases.[1,2]Here we reported a patient who was admitted to the hospital with severe metabolic acidosis and pulmonary hypertension and finally diagnosed with thiamine deficiency by detecting plasma vitamin B1 levels.Since clinically obvious thiamine deficiency is rare,and cases of thiamine deficiency requiring extracorporeal membrane oxygenation(ECMO)treatment are rarer,we believe that our case will be helpful for emergency clinicians.

Reliability of Echocardiographic Pulmonary Vascular Resistance to Screen for the New Definition of Precapillary Pulmonary Hypertension in Uncorrected Secundum Atrial Septal Defect

Background and Objective:The most feared complication of uncorrected secundum Atrial Septal Defect(ASD)is pulmonary arterial hypertension(PAH).Pulmonary vascular resistance(PVR)is crucial in detecting precapil-lary pulmonary hypertension(PH)to guide the need for PAH-specific therapy.There is a change in the cut-off value of PVR according to the recently updated PH guideline.How echocardiographic PVR(PVRecho)correlates to PVR by right heart catheterization(RHC)(PVRcath)according to the new guidelines has not been known.The aim of this study is to determine the reliability of PVRecho in detecting PAH in Uncorrected Ostium Secundum ASD based on the current updated guideline and to help screen the high PVR group.Methods:429 ostium secun-dum ASD in the COngenital HeARt Disease in Adult and Pulmonary Hypertension(COHARD-PH)registry was divided into three groups according to the PVR.PVRecho was calculated using Abbas’Formula and compared the its gold standard,the PVRcath.The correlation between the two methods was analyzed.The Bland-Altman plot was used to analyze the agreement between the two methods.Receiver operating characteristics(ROC)analysis was used to determine the PVRecho cut-off value for high PVR.Results:The majority of the population(63.5%)had high PVR.Female gender dominated the study population(84%).PVR_(echo) was significantly correlated with PVRcath(r=0.6225,p<0.0001).Bland-Altman plot among all groups and in subgroups analysis showed a wide range of agreement.PVRecho underestimated PVRcath 5.124 WU.In subgroup analysis,PVRecho overestimated PVRcath 0.35 WU in those with PVR<2 WU.In the second and third groups,PVR_(echo) underestimated PVRcath 0.52 and 10.77 WU,respectively.Conclusion:PVRecho is reliable in predicting high PVR in uncorrected secun-dum ASD.However,there is a wide range of agreement.PVR_(echo) cut-off value of>1.62 WU showed good dis-criminatory power in determining high PVR.

Pulmonary Hypertension Crisis in Patient with Tetralogy of Fallot and Mixed Total Anomalous Pulmonary Vein Connection after the Primary Correction:A Rare Case Report

Tetralogy of Fallot(TOF)with total anomalous pulmonary vein connections(TAPVC)is a rare type of complex congenital heart disease among all TOF cases.Co-presentation of major aortopulmonary collateral arteries(MAPCAs)compensates for the lack of central pulmonary bloodflow and decreases the severity of right-to-left shunting in TOF.We present a case of a 2-year-old child with complex diagnoses of TOF,TAPVC,a large secun-dum atrial septal defect(ASD),and intraoperatively identified MAPCAs.She underwent surgery to repair the TAPVC,valve-sparing reconstruction of the right ventricular outflow tract,interventricular defect closure,and the creation of patent foramen ovale(PFO).After the operation,hemodynamic instability happened along with sudden blood pressure drop,desaturation,and increased central venous pressure,which subsided after adminis-tering inhalational nitric oxide(NO).A postoperative pulmonary hypertension crisis was suggested when the patient experienced recurrent symptoms after the termination of NO.Echocardiographicfindings of a D-shaped left ventricle(LV),right-to-left PFO shunt and high tricuspid valve gradientfirmly established the diagnosis.It was subsequently managed with continuous NO inhalation and sildenafil,which rendered a satisfactory outcome.Repaired TOF and TAPVC could be at particular risk of developing pulmonary hypertension crisis,especially in the presence of MAPCAs due to possible remodeling of the pulmonary vasculature.Furthermore,a relatively non-compliant LV function and small left atrial size may exacerbate the risk of developing postcapillary pulmonary hypertension after TAPVC repair.A successful postoperative outcome calls for a meticulous preoperative analysis of the anatomical lesions,as well as careful monitoring.

Findings Associated with Pulmonary Hypertension: CT Angiography Based Study

Pulmonary hypertension (PH) is a complex disorder and may be related to a variety of diseases. It may arise in association with chronic thromboembolic pulmonary hypertension (CTEPH) or pulmonary embolism (PE). Knowledge of the radiological features is required to characterize and accurately diagnose the conditions and may improve the outcome. This study was designed to evaluate the clinical characteristics and the computerized tomography angiography findings in patients with PH, PE and CTEPH. Contrast-enhanced CT scans were acquired in 55 Sudanese patients with PE, 20 patients with PH, 25 patients with CTEPH and 50 normal subjects who were considered as control group. The CT diagnostic criteria for all cases were characterized. The clinical signs, parenchymal abnormalities, pulmonary tree and cardiac segments in all groups were characterized and compared with the control group. The results showed that the most common clinical characteristics were found to be chest pain, dyspnea, lower limb swelling, tachycardia and syncope which were correlated significantly with the presence of the disease. In all patients groups, the pulmonary vascular segments, cardiac segments and lung parenchyma changes were detected and were significantly different from the normal control subjects at p ≤ 0.01. It was found that CT angiography has a significant role in the diagnostic evaluation of these groups of patients. CT imaging is acceptably used in diagnosis, defining cause, quantifying heart segments and parenchyma changes in order to assess the feasibility of surgery, monitoring and therapeutic planning.

Pulmonary complications of portal hypertension:The overlooked decompensation

The systemic nature of cirrhosis and portal hypertension has long been recognized,and the amount of data characterizing the interplay between each system is becoming ever so complex.Lung involvement was among the first described associated entities in cirrhosis,with reports dating back to the late nineteenth century.However,it appears that throughout the years,interest in the pulmonary complications of portal hypertension has generally faded,especially in contrast to other decompensating events,as expertise in this field has primarily been concentrated in highly experienced tertiary care facilities and liver transplantation centers.Despite affecting up to 10%-15%of patients with advanced liver disease and having a proven prognostic impact,hepato-pulmonary syndrome,porto-pulmonary hypertension,and hepatic hydrothorax are frequently misdiagnosed,mistreated,or misinterpreted.This lack of precision might adversely impact patient care,referral to expert centers,and,ultimately,liver disease-related mortality and successful transplantation odds.The present minireview aims to increase awareness of the pulmonary complications of chronic liver disease by providing a brief overview of each of the three entities.The paper focuses on the essential theoretical aspects,addressing the most critical knowledge gaps on the one hand and,on the other hand,critically discussing one key issue for each complication.

The Role of Endogenous Carbon Monoxide in the Hypoxic Vascular Remodeling of Rat Model of Hypoxic Pulmonary Hypertension

We investigated the expression of heme oxygenase 1 (HO 1) gene and production of endogenous carbon monoxide (CO) in the rat lung tissue at different time points of chronic hypoxic pulmonary hypertension and the effect of hemin on the expression of HO 1 gene and pulmonary hypertension. A rat model of hypoxic pulmonary hypertension was recreated by exposure to intermittent normobaric hypoxic environment (10 % O 2). Reverse transcriptase polymerase chain reaction (RT PCR) was performed to determine the level of HO 1 mRNA in the rat lung tissue and double wave length spectrophotometry was used to evaluate the quantity of COHb in arterial blood. Cardiac catheterization was employed to measure the right ventricular systolic pressure (RVSP) and HE staining was performed in dissected lung tissue to observe the pathological changes of the intra acinar pulmonary arteries (IAPA). It was found that (1) There was a low level of HO 1 mRNA in normal rat lung tissue, but the level of HO 1 mRNA increased by 2-4 times in the lung tissue of hypoxic rats ( P <0.01). The quantity of COHb was 2-3 times those of control group ( P <0.01 or P <0.05). These were accompanied by the increased of RVSP and the thickened IAPA; (2) Hemin could keep the HO 1 mRNA and COHb in the hypoxic rat lung tissue at a high level, and partially suppressed the increase of rat RVSP, thereby ameliorating the pathological changes of IAPA. In conclusion, the upregulation of the expression of HO 1 gene and production of CO in the rat lung of hypoxic pulmonary hypertension plays a role of inhibition in the development of hypoxic pulmonary hypertension. Hemin has a therapeutic effect on hypoxic pulmonary hypertension.