Therapeutic effect of Sanhua decoction on rats with middle cerebral artery occlusion and the associated changes in gut microbiota and short-chain fatty acids.

Sanhua decoction (SHD), a traditional prescription, has long been used in treating ischemic stroke (IS). However, the therapeutic effect of SHD and the associated changes in gut microbiota and short-chain fatty acids (SCFAs) are uncertain. In this study, a rat model of IS was established by the middle cerebral artery occlusion (MCAO). By evaluating the cerebral infarct area and brain tissue pathology, it was found that SHD ameliorated IS-related symptoms in MCAO rats. Using 16S rRNA gene sequencing, we found that SHD reduced abnormally elevated Lactobacillus and opportunistic pathogens such as Desulfovibrio, but increased some beneficial bacteria that produce SCFAs, including Clostridia, Lachnospiraceae, Ruminococcaceae, and Coprococcus. KEGG analysis revealed that SHD regulates several pathways, including D-arginine and D-ornithine metabolism, polyketide sugar unit biosynthesis, and cyanoamino acid metabolism, which are significantly altered in MCAO rats. By gas chromatography-mass spectrometry detection of SCFAs, we found that fecal acetic acid, valeric acid, and caproic acid were significantly increased in MCAO rats, whereas propionic acid and isobutyric acid were decreased. SHD reversed the changes in acetic acid and propionic acid in the model rats and significantly increased fecal butyric acid. In addition, MCAO rats had significantly higher serum levels of acetic acid, butyric acid, isovaleric acid, and valeric acid, and lower levels of caproic acid. Altered serum levels of butyric acid, isovaleric acid, valeric acid, and caproic acid were restored, and the level of isobutyric acid was reduced after SHD administration. Spearman analysis revealed that cerebral infarct area had a strong correlation with Bifidobacterium, Desulfovibrio, Lachnospiraceae, Lactobacillus, acetic acid, valeric acid, and caproic acid. Overall, this study demonstrates for the first time that the effect of SHD on IS may be related to gut microbiota and SCFAs, providing a potential scientific explanation for the ameliorative effect of SHD on IS.

GSTM2 alleviates heart failure by inhibiting DNA damage in cardiomyocytes.

BACKGROUND: Heart failure (HF) seriously threatens human health worldwide. However, the pathological mechanisms underlying HF are still not fully clear. RESULTS: In this study, we performed proteomics and transcriptomics analyses on samples from human HF patients and healthy donors to obtain an overview of the detailed changes in protein and mRNA expression that occur during HF. We found substantial differences in protein expression changes between the atria and ventricles of myocardial tissues from patients with HF. Interestingly, the metabolic state of ventricular tissues was altered in HF samples, and inflammatory pathways were activated in atrial tissues. Through analysis of differentially expressed genes in HF samples, we found that several glutathione S-transferase (GST) family members, especially glutathione S-transferase M2-2 (GSTM2), were decreased in all the ventricular samples. Furthermore, GSTM2 overexpression effectively relieved the progression of cardiac hypertrophy in a transverse aortic constriction (TAC) surgery-induced HF mouse model. Moreover, we found that GSTM2 attenuated DNA damage and extrachromosomal circular DNA (eccDNA) production in cardiomyocytes, thereby ameliorating interferon-I-stimulated macrophage inflammation in heart tissues. CONCLUSIONS: Our study establishes a proteomic and transcriptomic map of human HF tissues, highlights the functional importance of GSTM2 in HF progression, and provides a novel therapeutic target for HF.

Dual Role of Pregnane X Receptor in Nonalcoholic Fatty Liver Disease.

The incidence of nonalcoholic fatty liver disease (NAFLD) has been rising worldwide in parallel with diabetes and metabolic syndrome. NAFLD refers to a spectrum of liver abnormalities with a variable course, ranging from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH), eventually leading to cirrhosis and hepatocellular carcinoma. Pregnane X receptor (PXR), a member of the nuclear receptor superfamily, plays a prominent part in the regulation of endogenous metabolic genes in NAFLD. Recent studies have suggested that PXR has therapeutic potential for NAFLD, yet the relationship between PXR and NAFLD remains controversial. In this review, PXR is proposed to play a dual role in the development and progression of NAFLD. Its activation will aggravate steatosis of the liver, reduce inflammatory response, and prevent liver fibrosis. In addition, the interactions between PXR, substance metabolism, inflammation, fibrosis, and gut microbiota in non-alcoholic fatty liver were elucidated. Due to limited therapeutic options, a better understanding of the contribution of PXR to the pathogenesis of NAFLD should facilitate the design of innovative drugs targeting NAFLD.

Qushi Huayu decoction ameliorates non-alcoholic fatty liver disease in rats by modulating gut microbiota and serum lipids.

Introduction: Non-alcoholic fatty liver disease (NAFLD) is a multifactorial disease. As a clinical empirical prescription of traditional Chinese medicine, Qushi Huayu decoction (QHD) has attracted considerable attention for its advantages in multi-target treatment of NAFLD. However, the intervention mechanism of QHD on abnormal lipid levels and gut microbiota in NAFLD has not been reported. Methods: Therefore, we verified the therapeutic effect of QHD on high-fat diet (HFD)-induced NAFLD in rats by physiological parameters and histopathological examination. In addition, studies on gut microbiota and serum lipidomics based on 16S rRNA sequencing and ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS) were conducted to elucidate the therapeutic mechanism of NAFLD in QHD. Results: The changes in gut microbiota in NAFLD rats are mainly reflected in their diversity and composition, while QHD treated rats restored these changes. The genera Blautia, Lactobacillus, Allobaculum, Lachnoclostridium and Bacteroides were predominant in the NAFLD group, whereas, Turicibacter, Blautia, Sporosarcina, Romboutsia, Clostridium_sensu_stricto_1, Allobaculum, and Psychrobacter were predominant in the NAFLD+QHD group. Lipid subclasses, including diacylglycerol (DG), triglycerides (TG), phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidic acid (PA), phosphatidylserine (PS), lysophosphatidylinositol (LPI), and phosphatidylglycerol (PG), were significantly different between the NAFLD and the control groups, while QHD treatment significantly altered the levels of DG, TG, PA, lysophosphatidylcholine (LPC), lysophosphatidylethanolamine (LPE), and platelet activating factor (PAF). Finally, Spearman's correlation analysis showed that NAFLD related differential lipid molecules were mainly associated with the genera of Bacteroides, Blautia, Lachnoclostridium, Clostridium_sensu_stricto_1, and Turicibacter, which were also significantly correlated with the biological parameters of NAFLD. Discussion: Taken together, QHD may exert beneficial effects by regulating the gut microbiota and thus intervening in serum lipids.

Case report: Transcatheter tricuspid valve intervention using K-Clip™ system after prior Kay's annuloplasty.

The K-Clip™ system is emerging as an alternative to correct tricuspid regurgitation (TR) for patients with high surgical risk. However, patients with recurrent severe tricuspid regurgitation after prior Kay's annuloplasty are not generally deemed to be candidates for K-Clip™ implantation. Herein, we report a case of a 63-year-old woman with recurrent symptomatic torrential tricuspid regurgitation 5 years after double valve replacement with Kay's annuloplasty of the tricuspid valve. The K-Clip™ was successfully implanted, and the severity of tricuspid regurgitation and dimensions of tricuspid annulus achieved significant reduction. In conclusion, K-Clip™ can still be feasible and effective for patients with prior Kay's annuloplasty. However, indications become more rigorous, and evaluation should be more comprehensive.

Decreased expression of RPL15 and RPL18 exacerbated the calcification of valve interstitial cells during aortic valve calcification.

Calcific aortic valve disease (CAVD) is the most common valvular heart disease, with an increasing prevalence due to an aging population. The pathobiology of CAVD is a multifaceted and actively regulated process, but the detailed mechanisms have not been elucidated. The present study aims to identify the differentially expressed genes (DEGs) in calcified aortic valve tissues, and to analyze the correlation between DEGs and clinical features in CAVD patients. The DEGs were screened by microarray in normal and CAVD groups (n = 2 for each group), and confirmed by quantitative real-time polymerase chain reaction in normal (n = 12) and calcified aortic valve tissues (n = 34). A total of 1048 DEGs were identified in calcified aortic valve tissues, including 227 upregulated mRNAs and 821 downregulated mRNAs. Based on multiple bioinformatic analyses, three 60S ribosomal subunit components (RPL15, RPL18, and RPL18A), and two 40S ribosomal subunit components (RPS15 and RPS21) were identified as the top 5 hub genes in the protein-protein interaction network of DEGs. The expression of RPL15 and RPL18 was also found significantly decreased in calcified aortic valve tissues (both p < .01), and negatively correlated with the osteogenic differentiation marker OPN in CAVD patients (both p < .01). Moreover, inhibition of RPL15 or RPL18 exacerbated the calcification of valve interstitial cells under osteogenic induction conditions. The present study proved that decreased expression of RPL15 and RPL18 was closely associated with aortic valve calcification, which provided valuable clues to find therapeutic targets for CAVD.

Acute Intraoperative Bioprosthetic Valve Thrombosis Immediately After Protamine Administration.

Acute bioprosthetic valve thrombosis (BPVT) is considered a rare complication and has seldom been described. Moreover, acute intraoperative BPVT is exceedingly rare, and its management remains a major clinical challenge. Here, we report a case of acute intraoperative BPVT that occurred immediately after protamine administration. Major resolution of the thrombus and significant improvement of bioprosthetic function were observed after the resumption of cardiopulmonary bypass support for approximately 1 hour. Intraoperative transesophageal echocardiography is important for a prompt diagnosis. Our case describes the spontaneous resolution of BPVT after reheparinization, which might assist in the management of acute intraoperative BPVT.

30-Day Outcomes of Transcatheter Tricuspid Annuloplasty With the K-Clip System: A Single-Center, Observational Study.

Background: Surgery for isolated functional tricuspid regurgitation (TR) poses a high risk. Several transcatheter approaches are being evaluated for the treatment of such patients. The K-Clip system is a percutaneous approach designed for functional TR; however, its utility remains unknown. Objectives: This study aimed to report the 30-day echocardiographic and clinical outcomes with the K-Clip system for severe TR, including changes in TR severity and NYHA functional class. Methods: Transcatheter tricuspid valve annuloplasty was performed in 39 patients with intermediate or high surgical risk who underwent the K-Clip system. The right internal jugular vein procedure was performed with annuloplasty guided by fluoroscopy and echocardiography. The primary outcomes were clinical success and all-cause mortality at the 30-day follow-up. Results: The K-Clip was successfully implanted in all cases, with 1 to 3 devices deployed. At the 30-day follow-up, none of the patients had died. TR severity was reduced by at least one grade in all patients. There were no severe procedural or 30-day adverse events, except for 1 new pacemaker implantation. The proportion of NYHA class III-IV patients decreased from 79.5% to 5.1%, and the ascites disappeared. The 6-minute walk distance increased by 78 m (P < 0.05), and the Kansas City Cardiomyopathy Questionnaire score improved by 11 points (P < 0.05). Conclusions: The K-Clip device is practical, safe, and effective for patients with severe TR. A 30-day reduction in TR and enhanced cardiac function and quality of life were associated with transcatheter tricuspid annuloplasty using the K-Clip device, according to short-term follow-up studies. (Confirmatory Clinical Study of Treating Tricuspid Regurgitation With K-Clip TM Transcatheter Annuloplasty System [TriStar]; NCT05173233).

A novel bidirectional side exiting pledgetted suture for valve replacement surgery.

The pledgetted mattress suture is one of the most widely used suture techniques for valve replacement surgery. However, the traditional pledgetted suture has several defects including intertwining of the sutures and the pledget flipping over. Here we present a novel side exiting pledgetted suture that can overcome these defects. It offers cardiac surgeons a new alternative for valve replacement surgeries.

The Role of Gut Microbiota-Bile Acids Axis in the Progression of Non-alcoholic Fatty Liver Disease.

Non-alcoholic fatty liver disease (NAFLD), an emerging global health problem affecting 25-30% of the total population, refers to excessive lipid accumulation in the liver accompanied by insulin resistance (IR) without significant alcohol intake. The increasing prevalence of NAFLD will lead to an increasing number of cirrhosis patients, as well as hepatocellular carcinoma (HCC) requiring liver transplantation, while the current treatments for NAFLD and its advanced diseases are suboptimal. Accordingly, it is necessary to find signaling pathways and targets related to the pathogenesis of NAFLD for the development of novel drugs. A large number of studies and reviews have described the critical roles of bile acids (BAs) and their receptors in the pathogenesis of NAFLD. The gut microbiota (GM), whose composition varies between healthy and NAFLD patients, promotes the transformation of more than 50 secondary bile acids and is involved in the pathophysiology of NAFLD through the GM-BAs axis. Correspondingly, BAs inhibit the overgrowth of GM and maintain a healthy gut through their antibacterial effects. Here we review the biosynthesis, enterohepatic circulation, and major receptors of BAs, as well as the relationship of GM, BAs, and the pathogenesis of NAFLD in different disease progression. This article also reviews several therapeutic approaches for the management and prevention of NAFLD targeting the GM-BAs axis.

Tricuspid Annulus Dilation in Patients With Combined Functional Tricuspid Regurgitation and Left-Heart Valvular Disease: Does Septal Annulus Not Dilate?

Background: This study aimed to investigate the course of tricuspid annulus dilation in functional tricuspid regurgitation with varied severities by direct intraoperative assessment. Methods: A total of 317 patients who underwent left heart surgery and concomitant tricuspid repair were divided into three groups according to the severity of the functional tricuspid regurgitation (mild, moderate and severe). Demographic and echocardiographic data were collected. The length of each tricuspid annulus segment was measured intraoperatively. The risk factors for preoperative severe functional tricuspid regurgitation and its postoperative recurrence were identified, and the impact of each tricuspid annulus segment on postoperative recurrence was compared. Results: In the course of tricuspid annulus dilation, the posterior annulus dilated 17% (group 1: 33.31 ± 6.94 mm vs. group 2: 35.56 ± 7.63 vs. group 3: 38.98 ± 8.70, p < 0.01), the anterior annulus dilated 13.4% (group 1: 36.71 ± 6.30 mm vs. group 2: 38.21 ± 8.35 vs. group 3: 41.63 ± 9.20, p < 0.01), and the septal annulus dilated 11.4% (group 1: 38.11 ± 5.28 mm vs. group 2: 39.76 ± 6.90 vs. group 3: 42.46 ± 7.50, p < 0.01). Tricuspid annulus circumference index (p < 0.01) independently correlated with preoperative severe tricuspid regurgitation and postoperative recurrence. When patients were grouped based on the length of each segment, the septal annulus demonstrated significantly higher sensitivity (p < 0.001) to postoperative recurrence than the anterior (p = 0.085) or posterior annulus (p = 0.262). Conclusions: This study revealed that each segment of tricuspid annulus could dilate in functional tricuspid regurgitation and highlighted the potential benefits of septal annulus plication in tricuspid annuloplasty, which may aid in the development of a methodology for prosthetic ring annuloplasty.

Association Between Plasma Lipoprotein Levels and Aortic Valve Calcification Among Patients with Aortic Valve Replacement Surgery: A Retrospective Study.

Objective: Calcific aortic valve disease (CAVD) is a prevalent type of valvular heart disease, its association with dyslipidemia remains controversial. Methods: Of 449 CAVD patients who underwent aortic valve replacement, 228 formed the aortic valve calcification (AVC) group, and 221 were the non-calcification group. We retrospectively reviewed the preoperative and one-year postoperative plasma lipoprotein levels of both and performed a logistic regression to evaluate the factors associated with AVC. Results: Preoperatively, AVC patients had significantly higher coronary heart disease (43.0% vs 24.9%, p<0.001), peripheral vascular disease (41.7% vs 26.2%, p<0.001), and heart failure rates (63.6% vs 47.1%, p<0.001), and a higher level of total cholesterol (4.1±0.9 vs 3.9±0.8 mmol/L, p=0.032) and very low-density cholesterol (0.6 (0.4-0.7) vs 0.5 (0.3-0.7) mmol/L, p=0.054). Echocardiography revealed a significant difference of aortic stenosis in both AVC and non-AVC groups (p<0.05), and also identified aortic regurgitation (AR) with a significant difference between these two groups (p=0.003). The peak transaortic jet velocity, peak transaortic gradient, and mean transaortic gradient were significantly higher in the calcification group (all p<0.001), but the aortic valve area (0.7 (0.5-1.0) vs 4 (0.9-4.5) cm2; p<0.001) was smaller. Age (OR=1.023), total cholesterol (OR=1.272), and mean transaortic gradient (OR=1.182) were AVC risk factors. A larger aortic valve area (OR=0.010) were protective factors. The one-year mortality and perivalvular leakage rates were significantly higher in the calcification group. Conclusion: Total cholesterol was significantly higher in AVC patients and may be an AVC risk factor along with age and mean transaortic gradient. AVC patients had a relatively poorer outcome within one year.

Case Report: Using Medtronic AP360 mechanical prosthesis in mitral valve replacement for patients with mitral insufficiency after primum atrial septal defect repair to reduce left ventricular outflow tract obstruction risk.

Background: Atrial septal defect is one of the most common congenital heart diseases in adults. Primum atrial septal defect (PASD) accounts for 4%-5% of congenital heart defects. Patients with PASD frequently suffer mitral insufficiency (MI), and thus, mitral valvuloplasty (MVP) or mitral valve replacement (MVR) is often required at the time of PASD repair. Unfortunately, recurrent unrepairable severe mitral regurgitation can develop in many patients undergoing PASD repair plus MVP in either short- or long-term after the repair surgery, requiring a re-do MVR. In those patients, the risk of left ventricular outflow tract obstruction (LVOTO) has increased. Case presentation: We present five such cases, ranging in age from 24 to 47 years, who had a PASD repair plus MVP or MVR for 14-40 years while suffering moderate to severe mitral regurgitation. Using Medtronic AP360 mechanical mitral prostheses, only one patient experienced mild LVOTO. Conclusions: The use of Medtronic AP360 mechanical mitral prostheses to perform MVR in patients with MI who had a history of PASD repair can potentially reduce the risk of LVOTO. Long-term follow-up is required to further confirm this clinical benefit associated with AP360 implantation in patients with PASD.

Four novel suture-sealing techniques to repair varying size paravalvular leaks.

BACKGROUND: Paravalvular leak (PVL) is a well-known complication of aortic valve replacement. Currently, there is no consensus on optimal intraoperative management of patients with mild-to-moderate or moderate PVL. TECHNIQUE: In this paper we present four novel surgical techniques, each combining suturing with sealing technique, to repair aortic PVLs, nullifying the need to replace the prosthesis. CONCLUSION: These techniques will offer cardiac surgeons new alternatives to the repair techniques currently used.

YTHDF2 alleviates cardiac hypertrophy via regulating Myh7 mRNA decoy.

BACKGROUND: Pathological cardiac hypertrophy is a major contributor of heart failure (HF), which seriously threatens human's health world widely. Deregulation of m6A RNA methylation, and m6A methyltransferases and de-methyltransferases have been demonstrated to act essential roles in cardiac hypertrophy and HF. Here, we studied the potential roles and its underlying mechanisms of m6A Reader YTHDF proteins in HF. In this study, we constructed HF mouse model by transverse aortic constriction surgery. Primary cardiomyocytes were isolated and stimulated with isoproterenol (ISO) or phenylephrine (PHE) to induce myocardial hypertrophy. RESULTS: Through single-cell RNA-seq analysis, immunofluorescent staining, HE staining, Western blotting, and real time-PCR detections, we found that YTHDF2 mRNA and protein level, but not YTHDF1 or YTHDF3, was significantly increased during HF development. YTHDF2 overexpression could efficiently alleviate cardiac hypertrophy. Furthermore, through immunoprecipitation accompanied with mass spectrometry analysis, Gene Ontology (GO) analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, we found that ISO stimulation did not evidently affect YTHDF2-interacting proteins. However, ISO or PHE stimulation significantly increased YTHDF2 protein interacting with Myh7 (beta-myosin heavy chain) mRNA, an important cardiac hypertrophy marker, in an m6A-dependent manner. Knockdown of Myh7 or deletion of the YTH domain of YTHDF2 reversed the protective effects of YTHDF2 on cardiac hypertrophy. Finally, we found that ISO or PHE stimulation promoted YTHDF2 protein expression through enhancing Ythdf2 mRNA stability in an m6A-dependent manner in cardiomyocytes. CONCLUSIONS: Overall, our results indicate that the m6A Reader YTHDF2 suppresses cardiac hypertrophy via Myh7 mRNA decoy in an m6A-dependent manner. This study highlights the functional importance of YTHDF2-dependent cardiac m6A mRNA regulation during cardiac hypertrophy, and provides a novel mechanistic insight into the therapeutic mechanisms of YTHDF2.

Small Cavity of Left Ventricle Does Not Affect Short-term Outcome in Patients with Rheumatic Mitral Valve Stenosis Undergoing Mitral Valve Replacement.

BACKGROUND: Small cavity left ventricle (SCLV) may affect the clinical outcomes of patients undergoing mitral valve replacement (MVR). This study aims to investigate the incidence of SCLV in patients with rheumatic mitral valve stenosis undergoing MVR and analyze its effect on short-term patient outcomes. METHODS: We retrospectively examined all consecutive patients with isolated or concomitant MVR for rheumatic mitral valve stenosis in our center from 2013 to 2018. SCLV was defined as end-diastolic volume index ≤ 50 ml/m2. After inclusion and exclusion, a total of 1,437 patients were analyzed. The baseline information was collected and compared between SCLV and non-SCLV patients. Multivariate logistic regression analysis was conducted to determine the effect of SCLV on early mortality. RESULTS: A total of 1,437 patients were included in the study. SCLV was detected in 13.57% of the patients. Compared with the non-SCLV group, patients with SCLV were smaller-sized and primarily female. There were no significant differences between SCLV and non-SCLV patients regarding major postoperative complications, nor were there incidence of prosthesis-patient mismatch. Logistic regression analysis showed that SCLV was not a risk factor for short-term mortality (P = 0.998). CONCLUSIONS: Our results demonstrated that SCLV was not associated with poorer early outcomes after MVR surgery in patients with rheumatic mitral valve stenosis.

Surgical treatment for anomalous origin of the right coronary artery from the pulmonary artery: a case report with five-year follow-up.

BACKGROUND: Anomalous origin of the right coronary artery from the pulmonary artery (ARCAPA) is a rare congenital heart disease affecting about 0.002% of the population. Knowledge of ARCAPA is almost collected from case reports. The aim of this study was to provide a rare case to better understand this rare congenital coronary anomaly. CASE PRESENTATION: We report a rare case of an 18-year-old male who was initially referred because of heart murmur. Dilated and tortuous coronary arteries were detected by echocardiography and congenital coronary anomaly was suggested. Further coronary CT angiography confirmed the diagnosis of ARCAPA. Although dual coronary system provides favorable long-term outcome, bypass surgery was considered technically difficult due to the huge mismatch of caliber between the right coronary artery and graft vessels. Eventually, simple right coronary artery ligation was performed. The patient was followed up for about 5 years without evidence of atherosclerosis or myocardial ischemia. CONCLUSIONS: ARCAPA presents as a rare congenital heart disease with variable clinical manifestations. Surgical treatment is highly recommended to re-establish dual coronary system and prevent further complications. To our best knowledge, only about 200 cases of ARCAPA has been reported.

Diagnostic mystery-a rare right ventricular cardiac hemangioma: a case report.

BACKGROUND: Cardiac hemangiomas are rare in all kinds of benign cardiac tumors. Although cardiac hemangiomas affect all ages and may occur anywhere within the heart, right ventricular hemangiomas are extremely uncommon. CASE PRESENTATION: We report a 56-year-old woman presented with chest tightness and breath shortness for 3 months. Transthoracic echocardiography and coronary computed tomography angiography showed a mass located adjacent to the apex of the right ventricle but both failed to figure out where the mass originated from, remaining a diagnostic mystery preoperatively. The mass was removed successfully and the histopathological examination confirmed it was hemangioma. CONCLUSIONS: Cardiac magnetic resonance should be the ultimate diagnostic tool of cardiac tumors. Surgical removal, associated with a low recurrence rate and long-term survival benefits, should be the first choice of therapy for cardiac hemangiomas.

Surgical lobectomy of pulmonary arteriovenous malformations in a patient with presentations regarded as sequela of tuberculosis: a case report.

BACKGROUND: Pulmonary arteriovenous malformations are uncommon conditions of abnormal communications between pulmonary arteries and veins, which are most commonly congenital in nature. Although such condition is not extremely rare, it is a challenge to the differential diagnosis of pulmonary problems such as hypoxemia and pulmonary lesions. CASE PRESENTATION: We report a meaningful case of a 23-year-old male presented with elevated hemoglobin (23.0 g/dl) on admission. Physical examination revealed cyanosis, digital clubbing and low oxygen saturation on room air. The patient was initially diagnosed as polycythemia vera while the subsequent result of bone marrow aspiration was negative. During further assessment, pulmonary arteriovenous malformations were detected by CT pulmonary angiography. Lobectomy was successfully performed with significant increase in oxygen saturation from 86 to 98%. The hemoglobin decreased to almost normal level of 14.9 g/dl 3 months after surgery and the patient had been followed up for nearly 5 years. CONCLUSIONS: Pulmonary arteriovenous malformations should be suspected in patients with central cyanosis, digital clubbing, polycythemia, pulmonary lesion and without cardiac malformations. Embolization or surgery is strongly recommended to reduce the risks caused by pulmonary arteriovenous malformations.