Cheng Hong

Visualization of Peripheral Pulmonary Artery Red Thrombi Utilizing Optical Coherence Tomography

Optical coherence tomography (OCT) is a new imaging technique capable of obtaining high-resolution intravascular images and has been used in interventional cardiology. However, an application of OCT in pulmonary arteries had seldom been documented. In this case, OCT imaging is performed in peripheral pulmonary arteries and shows mural red thrombi. Subsequently, the red thrombi are aspirated and confirmed by a histological examination. These findings suggest that OCT may be a useful tool to depict peripheral pulmonary artery thrombi.

Clinical study of optical coherence tomography in the diagnosis of peripheral pulmonary artery thrombus

BACKGROUND Peripheral pulmonary artery thrombus (PPT) is common in the clinic. However, due to the lack of an ideal diagnostic tool, PPT cannot be quickly diagnosed and effectively treated at present. Optical coherence tomography (OCT) is a new intravascular imaging technique that is characterized by high image resolution. This technique is suitable for small vessel imaging and has the ability to distinguish red and white thrombi. OBJECTIVE This study aimed to evaluate the value of OCT in the diagnosis of PPT and in identifying the nature of thrombi by comparing the difference in sensitivity between OCT and selective pulmonary angiography (SPA). METHODS Highly suspected PPT patients were enrolled in this study. Pulmonary ventilation/perfusion (V/Q) mismatch pulmonary segments or peripheral pulmonary arteries were chosen. SPA was performed first, followed by OCT imaging. The diagnostic standard of thrombus with SPA was an intraluminal filling defect. The procedure and criteria for OCT diagnosis of thrombus were previously introduced in intracoronary OCT thrombus images. The diameter of the imaging vessels was measured, and they were grouped according to diameter. The diameter was <2mm in the distal segment group, 2-3mm in the middle segment group, and >3mm in the proximal segment group. The recognition abilities of intravascular thrombus with the different diameters of these two techniques were compared. Patients with obvious clinical symptoms and more red thromboses revealed by OCT were given standardized anticoagulant therapy for half a year. The clinical symptoms, 6-minute walking test and changes in the thrombus in the OCT images of these patients before and after treatment were observed. RESULTS A total of 22 patients with highly suspected PPT were suggested to undergo V/Q inspection. Finally, 12 patients were eligible for the study. SPA and OCT were performed in 61 peripheral pulmonary arteries in all 12 patients. The ideal SPA and OCT images obtained from a total of 76 blood vessel segments were suitable for comparative analysis. A total of 62 thrombi were found by SPA. Among these, eight thrombi were in the distal segment, 29 thrombi were in the middle segment, and 25 thrombi were in the proximal segment. A total of 81 thrombi were found by OCT, among which 22 thrombi were in the distal segment, 31 were in the middle segment, and 28 were in the proximal segment. There was a significant difference between two groups in the distal segment group (P=0.013), while there was no significant difference between two groups in the middle segment group or the proximal segment group (P>0.05). In addition to all the thrombi found by SPA, OCT found other thrombi that were missed by SPA. According to previous OCT images for determining the nature of thrombi, OCT revealed 81 thrombi, of which 48 (59%) were red thrombi and 33 (41%) were white thrombi. Then, seven patients who had obvious clinical symptoms and more red thrombi in the peripheral pulmonary artery were given anticoagulant therapy for six months. After treatment, these symptoms were improved, oxygenation indexes increased, and the six-minute walking test was extended in all these patients. After anticoagulation therapy, five patients underwent OCT review. These OCT images were matched and compared before and after anticoagulation therapy. The results revealed that most of the thrombi had disappeared, and a small amount of red thrombi turned white as the volume reduced. The mean lumen area before and after treatment was 2.05±1.03mm2 and 2.86±1.24mm2, respectively, and the difference was statistically significant (P=0.035). CONCLUSION OCT can clearly show the structure of the lumen and the wall of the peripheral pulmonary artery tube. The sensitivity of the diagnosis of PPT with a diameter of <2mm was higher than that of SPA. Moreover, OCT has the ability to distinguish between red and white thrombi, which is of guiding significance in anticoagulant therapy.

Optical coherence tomography in imaging of peripheral pulmonary arteries

BACKGROUND To establish an optical coherence tomography (OCT)-based method for imaging peripheral pulmonary arteries. METHODS We recruited eight patients (five men; average age, 48±12 years; peripheral pulmonary artery thrombosis, three patients; idiopathic pulmonary hypertension, three patients; interstitial lung disease, two patients) who underwent OCT of the peripheral pulmonary arteries in the First Affiliated Hospital of Guangzhou Medical University and Guangzhou Institute of Respiratory Diseases, between September 2009 and September 2010. OCT was performed using both the conventional OCT imaging method (COI) and the improved pulmonary artery imaging method (IPI). In the IPI, contrast agent was used as an indicator of balloon inflation meanwhile increases in flushing speed of the replacement fluid. The percentage of optimal images, inflation pressure, flushing speeds and complications were compared between the two methods. RESULTS We performed OCT of 33 vessel segments by both methods. IPI produced more optimal images than COI (88% vs. 24%). Mean inflation pressure and flushing speed were higher during IPI than COI (0.62±0.15 vs. 0.43±0.08 atm; 1 atm =101.3 kPa; 0.82±0.10 vs. 0.42±0.06 mL/s; both P<0.01). Decreased blood oxygen saturation (SaO2) was associated with 9% and 30% segments (P<0.01) in the COI (mean decrease, 8.4%±3.6%) and IPI groups (mean decrease, 12.1%±5.3%; P<0.05) respectively. SaO2 recovered to pre-imaging levels after oxygen inhalation. CONCLUSIONS IPI is safe and effective for OCT of peripheral pulmonary arteries.

Application value of the NoSAS score for screening sleep-disordered breathing

Background Diagnosis of sleep-disordered breathing (SDB) requires overnight polysomnography (PSG). Because of the cost and low availability of these procedures, the NoSAS score was developed to identify subjects at high risk of SDB. To evaluate the clinical utility of the NoSAS score for screening patients with SDB in China and to compare the predictive value of the NoSAS score with the Epworth Sleepiness Scale (ESS), we used the STOP-Bang questionnaire and the Berlin questionnaire. Methods In our study, we retrospectively reviewed the existing clinical data of patients who underwent an overnight PSG for suspected SDB from June 2014 to September 2017 at the sleep medical center of Guangdong Medical University Affiliated Second Hospital. The information we collected included all parts of the NoSAS score, the ESS, the STOP-Bang questionnaire and the Berlin questionnaire. Based on the severity of SDB determined by the apnea-hypopnea index (AHI), the patients were classified into four groups of primary snoring (<5 events/h), mild SBD (AHI ≥5 and <15 events/h), moderate SBD (AHI ≥15 and ≤30 events/h) and severe SBD (>30 events/h). We calculated the sensitivity, specificity, positive predictive value, negative predictive value and area under the receiver operating characteristic curve of the five questionnaires to compare their relative efficacy for screening SDB. Results A total of 479 consecutive patients (374 males and 105 females) ranging in age from 18 to 80 years old (mean ± SD, 48.9±14.4 years old) were recruited into this study. When using the standard of AHI ≥5 for diagnosing SDB, the NoSAS score had the largest area under the curve (AUC) (AUC =0.734), and the Berlin questionnaire (AUC =0.732) came second. Both exhibited a better predictive value than the ESS score and the STOP-Bang questionnaire. Using NoSAS ≥8 to predict AHI ≥5 events/h, AHI ≥15 events/h and AHI >30 events/h, the sensitivity and specificity were 0.590 and 0.707, 0.649 and 0.626, and 0.644 and 0.562, respectively; for the STOP-Bang questionnaire, the values were 0.721 and 0.512, 0.752 and 0.440, and 0.763 and 0.399, respectively; and for the Berlin questionnaire, the values were 0.721 and 0.512, 0.752 and 0.440, and 0.763 and 0.399, respectively. Conclusions The NoSAS score and the Berlin questionnaire both exhibited good predictive value for SDB patients. NoSAS is a more suitable questionnaire to use in clinic for the conveniences but the similar performance with another questionnaire.

Modulation of EPC: A new hope for pulmonary artery hypertension treatment

We have read with great interest of the recently published article entitled “Effect of targeted therapy on circulating progenitor cells in precapillary pulmonary hypertension” by García-Lucio J et al. [1]. In this study, the number of circulating endothelial progenitor cells (EPC) is lower in naïve pulmonary artery hypertension (PAH) patients, and treatment of PAH-targeted drugs increased EPC levels in the blood of PAH patients. However, there is no elevation of circulating EPC in chronic thromboembolic pulmonary hypertension patients. Previous reports suggest that the level of circulating EPC is positively correlated with pulmonary artery pressure [2]; moreover, EPC from PAH patients treated with treprostinil showed a more proliferative phenotype and more angiogenic potential [3]. Animal study showed that infusion of EPC from monocrotaline-induced murine PAH model increases the pulmonary artery pressure of healthy animals [4]. These may indicate that the reduction of EPC number and dysfunction of EPC are involved in the pathogenesis of PAH; targeted therapy for PAH may decrease pulmonary artery remodeling at least partially through improving the proliferation and function of EPCs. Recent studies showed that

Pulmonary Capillary Hemangiomatosis without Pulmonary Hypertension: An Early Stage of Disease?

A 14‐year‐old male visited the First Affiliated Hospital of Guangzhou Medical University with a complaint of a 2‐year history of progressive exertional dyspnea and fingertips cyanosis. Physical examination revealed remarkable desaturation measured by pulse oximetry (80% at rest) and marked cyanosis of lips. The high‐resolution computed tomography scanning revealed no significant abnormality in the lung field [Figure 1a and 1b]. Computed tomography of pulmonary angiography showed no filling defect in trunk or branches of pulmonary arteries, no dilated central pulmonary arteries, and no cardiomegaly [Figure 1c and 1d]. Cardiac catheterization showed a mean right atrial pressure of 6 mmHg, pulmonary artery pressure with mean of 12 mmHg, pulmonary capillary wedge pressure of 9 mmHg, cardiac output of 6.2 L/min, and cardiac index of 4.10 L·min−1·m−2. Pulmonary vascular resistance was slightly elevated at 4.52 wood units. Lung biopsy revealed that lower lobe alveolar spaces were filled with red blood cells or hemosiderin cells, and alveolar septum was wider than normal. Hematoxylin and eosin staining shows that capillary proliferations within alveolar and bronchiolar walls were visible throughout most areas [Figure 2a‐2c]. Immunostaining of lung section was strongly positive for CD34 [Figure 2d], CD31 [Figure 2e], and F8 [Figure 2f]. The clinical manifestations, pathological findings, and immunohistochemistry supported definitive diagnosis of pulmonary capillary hemangiomatosis (PCH) with normal pulmonary artery blood pressure and normal radiological appearance. Because of financial difficulties, the patient abandoned heart–lung transplantation and left hospital without therapeutic intervention. Follow‐up to nearly a years, the patient was stable with no prominent hypoxia on 2 L/min supplemental nasal cannula oxygen at home. Written informed consent was obtained from the parents of patient for publication of this case report and any accompanying images. All patients with PCH usually have elevated pulmonary arterial pressures measured by right heart catheterization with normal or low pulmonary capillary wedge pressure and this have been demonstrated.[1] The infiltration of pulmonary vessel and intrapulmonary shunting caused by uncontrolled proliferation of the pulmonary capillaries might be responsible for the pulmonary hypertension and Pulmonary Capillary Hemangiomatosis without Pulmonary Hypertension: An Early Stage of Disease?

Comparison of rivaroxaban mono-therapy and standard-therapy adjusted by CYP2C9 and VKORC1 genotypes in symptomatic pulmonary embolism

RATIONALE Pulmonary embolism (PE) is a life-threatening manifestation of venous thromboembolism. Rivaroxaban is an oral anticoagulant, which directly inhibits Factor Xa. The objective of the current study was, in comparison to the standard-therapy method, to investigate the potential of rivaroxaban to improve the treatment of patients with PE, and to reduce hemorrhage in the standard-therapy group through adjusting the dose of warfarin by CYP2C9 and VKORC1 genotypes. METHODS Sixty-two PE patients with or without deep venous thrombosis (DVT) was randomized to rivaroxaban mono-therapy or standard-therapy with enoxaparin followed by vitamin K antagonist (VKA). Concentration of the anticoagulants was adjusted according to the results of CYP2C9 and VKORC1 genotypes in order to stabilize the international normalized rate (INR) at 2.0-3.0 range. Length of hospital stay at initial hospitalization was compared, therapeutic efficacy was examined by computed tomographic pulmonary angiography (CTPA) and ventilation/perfusion (V/Q) scan, and side-effect of anti-coagulants was monitored at 1-month, and 3- or 6-months follow-up check points. RESULTS We found that, overall, patients who received rivaroxaban mono-therapy had a significantly shorter length of hospital stay compared with patients who received standard-therapy of enoxaparin followed by VKA (9.29±3.70 versus 11.38±3.12days, P=0.021). The therapeutic efficacy was of no marked difference between these two groups. However, after one month treatment, 50% (16/32) of the standard-therapy group had mild hemorrhage, which was significantly higher than that of rivaroxaban mono-therapy group (16.7%, 5/30, P=0.006). Moreover, a significantly higher rate in the standard-therapy group (22.2% versus 3.4%, P=0.032) was found after 3 or 6months therapy. Major bleeding was slightly but not significantly higher in the standard-therapy group than that in the rivaroxaban therapy group. In addition, 2 (6.3%) patients died from Life-threatening bleeding in the standard-therapy group. CONCLUSION Findings of the current study suggested that rivaroxaban mono-therapy result in shorter hospital stay compared to the standard-therapy. Implication of CYP2C9 and VKORC1 genotypes in determining dose of warfarin, however, remains to be further examined in larger cohort studies.