SARS-CoV-2 Omicron variant replication in human bronchus and lung ex vivo.

The emergence of SARS-CoV-2 variants of concern with progressively increased transmissibility between humans is a threat to global public health. The Omicron variant of SARS-CoV-2 also evades immunity from natural infection or vaccines1, but it is unclear whether its exceptional transmissibility is due to immune evasion or intrinsic virological properties. Here we compared the replication competence and cellular tropism of the wild-type virus and the D614G, Alpha (B.1.1.7), Beta (B.1.351), Delta (B.1.617.2) and Omicron (B.1.1.529) variants in ex vivo explant cultures of human bronchi and lungs. We also evaluated the dependence on TMPRSS2 and cathepsins for infection. We show that Omicron replicates faster than all other SARS-CoV-2 variants studied in the bronchi but less efficiently in the lung parenchyma. All variants of concern have similar cellular tropism compared to the wild type. Omicron is more dependent on cathepsins than the other variants of concern tested, suggesting that the Omicron variant enters cells through a different route compared with the other variants. The lower replication competence of Omicron in the human lungs may explain the reduced severity of Omicron that is now being reported in epidemiological studies, although determinants of severity are multifactorial. These findings provide important biological correlates to previous epidemiological observations.

Replication of Novel Zoonotic-Like Influenza A(H3N8) Virus in Ex Vivo Human Bronchus and Lung.

Human infection with avian influenza A(H3N8) virus is uncommon but can lead to acute respiratory distress syndrome. In explant cultures of the human bronchus and lung, novel H3N8 virus showed limited replication efficiency in bronchial and lung tissue but had a higher replication than avian H3N8 virus in lung tissue.

Hybrid approach for cerebral protection in open-heart surgery: Case series.

BACKGROUND: Stroke remains one of the most important complications of cardiac surgery and occurs in 2.2% after open-heart procedure. It is associated with significant morbidity and mortality. The use of a cerebral protection system during transcatheter aortic valve implantation may be associated with a lower risk of periprocedural strokes, and mortality at 30 days. The aim of the present study was to assess the safety and feasibility of this device in patients at high risk for stroke during open cardiac surgery. METHODS: We present six patients with a high risk of perioperative stroke who underwent placement of Sentinel cerebral protection system during various open-heart operations between 2018 and 2021. RESULTS: The system was successfully deployed, and debris was retrieved in all patients. There was no device-related complication or development of ischemic stroke postoperatively. One patient suffered from intracranial hemorrhage due to peri-operative coagulopathy. CONCLUSIONS: We demonstrated the feasibility and safety of this hybrid approach with a high debris capture rate. It encourages further study to evaluate the benefits of the Sentinel cerebral protection system in reducing stroke and mortality in selected patients undergoing open-heart surgery.

Intracardiac foreign body: A rare cause of recurrent fungemia.

BACKGROUND: An intracardiac foreign body causing recurrent fungemia is a rare clinical situation. Clinicians should be that aware of rare sources of sepsis despite a thorough history and examination. RESULTS: The authors describe a 63 year-old man, with unremarkable past medical history, who presented with a fever for 2 weeks. Blood cultures persistently grew Candida albicans and Streptococcus constellatus. Echocardiogram assessment showed a suspected vegetation over the tricuspid valve. Surgical exploration with median sternotomy and cardiopulmonary bypass revealed a tooth-pick impacted within the right atrium surrounded by vegetation. The authors postulate accidental ingestion of the foreign body and translocation into the right atrium via the esophagus and thoracic cavity. CONCLUSION: Surgical removal of symptomatic intracardiac foreign bodies is highly recommended.

Donor-Derived Genotype 4 Hepatitis E Virus Infection, Hong Kong, China, 2018.

Hepatitis E virus (HEV) genotype 4 (HEV-4) is an emerging cause of acute hepatitis in China. Less is known about the clinical characteristics and natural history of HEV-4 than HEV genotype 3 infections in immunocompromised patients. We report transmission of HEV-4 from a deceased organ donor to 5 transplant recipients. The donor had been viremic but HEV IgM and IgG seronegative, and liver function test results were within reference ranges. After a mean of 52 days after transplantation, hepatitis developed in all 5 recipients; in the liver graft recipient, disease was severe and with progressive portal hypertension. Despite reduced immunosuppression, all HEV-4 infections progressed to persistent hepatitis. Four patients received ribavirin and showed evidence of response after 2 months. This study highlights the role of organ donation in HEV transmission, provides additional data on the natural history of HEV-4 infection, and points out differences between genotype 3 and 4 infections in immunocompromised patients.

Japanese Encephalitis Virus Transmitted Via Blood Transfusion, Hong Kong, China.

Japanese encephalitis virus (JEV) is a mosquitoborne virus endemic to China and Southeast Asia that causes severe encephalitis in <1% of infected persons. Transmission of JEV via blood transfusion has not been reported. We report transmission of JEV via blood donation products from an asymptomatic viremic donor to 2 immunocompromised recipients. One recipient on high-dose immunosuppressive drugs received JEV-positive packed red blood cells after a double lung transplant; severe encephalitis and a poor clinical outcome resulted. JEV RNA was detected in serum, cerebrospinal fluid, and bronchoalveolar lavage fluid specimens. The second recipient had leukemia and received platelets after undergoing chemotherapy. This patient was asymptomatic; JEV infection was confirmed in this person by IgM seroconversion. This study illustrates that, consistent with other pathogenic flaviviruses, JEV can be transmitted via blood products. Targeted donor screening and pathogen reduction technologies could be used to prevent transfusion-transmitted JEV infection in highly JEV-endemic areas.

Left ventricular assist device insertion and open abdominal aortic aneurysm repair in same admission for an end-stage heart failure patient.

Patients suffering from end-stage heart failure also suffer from multiple cardiovascular comorbidities such as abdominal aortic aneurysm (AAA). Mechanical support with left ventricular assist device with open repair of AAA repair has rarely been reported in literature. The authors describe a 60-year-old male with end-stage heart failure and a symptomatic AAA with sequential left ventricular assist device insertion and open AAA repair with aortic cross-clamping.

Replication of SARS-CoV-2 Omicron BA.2 variant in ex vivo cultures of the human upper and lower respiratory tract.

BACKGROUND: The Omicron BA.2 sublineage has replaced BA.1 worldwide and has comparable levels of immune evasion to BA.1. These observations suggest that the increased transmissibility of BA.2 cannot be explained by the antibody evasion. METHODS: Here, we characterized the replication competence and respiratory tissue tropism of three Omicron variants (BA.1, BA.1.1, BA.2), and compared these with the wild-type virus and Delta variant, in human nasal, bronchial and lung tissues cultured ex vivo. FINDINGS: BA.2 replicated more efficiently in nasal and bronchial tissues at 33°C than wild-type, Delta and BA.1. Both BA.2 and BA.1 had higher replication competence than wild-type and Delta viruses in bronchial tissues at 37°C. BA.1, BA.1.1 and BA.2 replicated at a lower level in lung parenchymal tissues compared to wild-type and Delta viruses. INTERPRETATION: Higher replication competence of Omicron BA.2 in the human upper airway at 33°C than BA.1 may be one of the reasons to explain the current advantage of BA.2 over BA.1. A lower replication level of the tested Omicron variants in human lung tissues is in line with the clinical manifestations of decreased disease severity of patients infected with the Omicron strains compared with other ancestral strains. FUNDING: This work was supported by US National Institute of Allergy and Infectious Diseases and the Theme-Based Research Scheme under University Grants Committee of Hong Kong Special Administrative Region, China.

Aortic dissection in a Chinese patient 31 years after surgical repair of tetralogy of Fallot.

Aortic dilation has been increasingly recognized in congenital heart diseases, and aortic dissection is one of the important complications. We report a case of aortic dissection in a patient 31 years after repair of tetralogy of Fallot (TOF) and review reported cases. While aortic dissection is uncommon, aortic dilation is common among patients with repaired TOF and it appeared progressive in some patients. Based on the reported cases, progressive aortic dilation appeared as the pre-requisite for aortic dissection, although other factors might be involved. Regular surveillance and monitoring for aortic complications should be incorporated into clinical practice. .

Isolated left ventricular non-compaction: an unusual indication for heart transplantation.

We report a patient with isolated left ventricular non-compaction diagnosed by echocardiography and cardiac magnetic resonance imaging. She developed refractory congestive heart failure and subsequently underwent successful heart transplantation. This type of cardiomyopathy is thought to be caused by the arrest of normal embryogenesis of the endocardium and myocardium. The spectrum of clinical, radiological, and pathological abnormalities is discussed.

Minimally invasive thoracic surgery: beyond surgical access.

Thoracic surgery has evolved throughout the decades. The difficulty of accessing the intrathoracic organs through the bony rib-cage has been a challenge for thoracic surgeons. In the past, large incisions stretching across the chest, such as posterolateral thoracotomies with rib spreading was the standard approach to access the lungs. These methods cause large amounts of trauma to the patient, with high rates of mortality and morbidity. However, with the advances in technology and the improvements in surgical technique, thoracic surgery has progressed to minimise trauma to the patient while still maintaining oncological and surgical principles. State-of-the-art technology, combined with wide variety of old and new surgical techniques give the thoracic surgeon a formidable armamentarium. Although there has been a focus on reducing the number and size of surgical wounds, considerations other than surgical approach can reduce the trauma suffered by the patient. Preservation of pulmonary function via organ preservation and anaesthetic techniques to further minimise the systemic inflammation such as non-intubated anaesthesia have also been shown to improve patient outcomes. This article aims to review the recent advances in minimally invasive thoracic surgery.

The history of lung transplantation in Hong Kong.

Clinical lung transplant was first performed in Hong Kong in 1995. In the early years, the volume of activity was very low. There has been a clear trend of increasing volume in the past few years. The recipient pathology is very different from the International Society for Heart and Lung Transplantation (ISHLT) database, with complete absence of cystic fibrosis and alpha-1-antitrypsin deficiency, and a predominance of diseases of the pulmonary circulation. Lymphangioleiomyomatosis (LAM) has a much higher representation on the waiting list than the ISHLT. The survival of patients who received a lung transplant in Hong Kong compares favorably with international data.

Late tricuspid surgery: predicting outcome with computed tomography.

Tricuspid regurgitation can progressively worsen years after left-sided heart valve surgery, requiring surgical intervention for which the prognostic factors are unclear. This study aimed to assess the prediction of surgical outcome using right ventricular function obtained from computed tomography. We prospectively enrolled 24 patients who underwent isolated tricuspid repair or replacement from 2005 to 2008. Right ventricular computed tomography was carried out before surgery. The primary endpoint was survival with symptomatic improvement after one year. Twelve patients survived with improvement of at least one New York Heart Association functional class, and 12 died or had no symptomatic improvement. All baseline characteristics, echocardiogram data, and surgical details were similar in both groups. Right ventricular computed tomography parameters including end-systolic volume, indexed end-systolic volume, end-diastolic volume, and indexed end-diastolic volume were significantly different between the two groups. We concluded that right ventricular function assessed by computed tomography can predict the surgical outcome in patients undergoing surgery for isolated late tricuspid regurgitation.

Pneumatic pump reduces leg wound complications in cardiac patients.

Leg wound complications at the site of vein harvest for coronary artery bypass graft, although infrequent, cause significant morbidity. Pneumatic pressure therapy is valuable in venous and lymphatic diseases, but its usefulness after leg vein harvest has not been determined. A prospective randomized controlled trial was conducted on 200 patients, half of whom had sequential pneumatic leg pump therapy postoperatively. Wound healing, extent of lower limb edema, patient satisfaction, and the financial implications of pneumatic pressure therapy were assessed. In the study group, 71 patients had satisfactory wound healing vs. 23 in the control group. The leg wound infection rate in the study group was 3% vs. 15% in the control group ( p = 0.003). Lower limb edema was significantly reduced in the study group in the early postoperative period ( p < 0.05), and the mean postoperative length of hospital stay was reduced by 2.6 days in patients given pneumatic pressure therapy ( p = 0.003). The sequential pneumatic leg pump is an effective, inexpensive, and convenient device that reduces leg wound complications after coronary artery bypass grafting.

Mitral valve annuloplasty with Carpentier-Edwards physio ring: mid-term results.

The mid-term results of mitral valve repair with the Carpentier-Edwards Physio annuloplasty ring were assessed in 97 consecutive patients in a single tertiary-referral cardiothoracic surgical center. The mean follow-up time was 3.9 years (range, 1 month to 8.9 years). Most patients were in functional class II and III before the operation. Ejection fraction was < 40% in 8 patients. Causes of mitral regurgitation included degenerative disease (66%), infective endocarditis (13.4%), rheumatic disease (10.3%), and ischemic heart disease (9.3%). Thirty-day mortality was 2.1%. Actuarial survival and freedom from re-operation at 8 years were 91% and 90.8%, respectively. The only significant risk factor for re-operation was residual mitral regurgitation. Four patients suffered thromboembolic complications, giving an overall event-free survival of 93% +/- 3.7% during the follow-up period. The Carpentier-Edwards Physio ring provides safe and effective repair of mitral regurgitation on mid-term follow-up.