Long COVID and Wavering Incidence of Pulmonary Embolism: A Systematic Review

Pulmonary embolism (PE) is a serious medical condition that can occur as a result of venous thromboembolism (VTE). COVID-19, also known as Post-Acute Sequelae of SARS-CoV-2 infection (PASC), can potentially lead to PE due to the formation of blood clots in the lungs. This study aims to collate and report trends of PE in patients with long COVID (4-12 weeks since infection) and post-COVID-19 syndrome (>12 weeks since infection). The study adhered to PRISMA Statement 2020 guidelines, and a systematic search was conducted in four databases. In total, nine observational studies were included with a total patient count of 45,825,187. The incidence of PE with long COVID/post-COVID-19 syndrome was seen among 31,885 individuals out of 44,967,887 participants. The incidence rate of PE was observed as 0.07%, given that the studies included matched controls. While we cannot state with certainty that COVID-19 infection in itself leads to higher risks of PE at a later time, this study emphasizes the need for optimized care and longitudinal studies during the COVID-19 era to account for deviations from the norm.

Natriuretic Peptide Levels and Clinical Outcomes among Patients Hospitalized with COVID-19 Infection

Purpose

There is increasing evidence of adverse cardiovascular morbidity associated with SARS-CoV-2 (COVID-19). Pro-B-type natriuretic peptide (proBNP) is a biomarker of myocardial stress associated with outcomes in various respiratory and cardiac diseases. We hypothesized that proBNP level would be associated with mortality and clinical outcomes in hospitalized COVID-19 patients.

Methods

We performed a retrospective analysis of hospitalized COVID-19 patients (n=1232) using adjusted logistic and linear regression to assess the association of admission proBNP (analyzed by both categorical cutoff >125 pg/mL and continuous log transformed proBNP) with clinical outcomes. Covariates included age, sex, race, body mass index (BMI), hypertension, coronary artery disease (CAD), diabetes, smoking history, and chronic kidney disease stage (Model 1), with Troponin I added in Model 2. We performed survival analysis by a multivariate Cox proportional hazard model, incorporating log transformed proBNP. We additionally treated BMI, a strong potential confounder of both proBNP levels and COVID-19 outcomes, as an ordinal variable ordered across tertiles.

Results

Patients were mean age 62.9±17.6, 53.8% male, and 35.9% Black. Preadmission comorbidities were hypertension (57.1%), diabetes (31.6%), CAD (9.0%) and heart failure (HF, 10.6%). In Model 1 and 2, higher proBNP level was significantly associated with death, new HF, length of stay, ICU duration and need for ventilation among hospitalized COVID-19 patients. This significance persisted after ordinal compression of BMI across tertiles. The adjusted hazard ratio of death for log[proBNP] was 1.56 (95% CI: 1.23-1.97; P<0.0001).

Conclusion

Using a relatively large and racially diverse hospitalized COVID-19 patient cohort, we find that proBNP is associated with adverse clinical outcomes, including mortality and new HF in COVID-19. Further prospective investigation is warranted on the utility of proBNP for clinical prognostication in COVID-19.

Identification of peripheral CD154+ T cells and HLA-DRB1 as biomarkers of acute cellular rejection in adult liver transplant recipients

Decreasing graft rejection and increasing graft and patient survival are great challenges facing liver transplantation (LT). Different T cell subsets participate in the acute cellular rejection (ACR) of the allograft. Cell-mediated immunity markers of the recipient could help to understand the mechanisms underlying acute rejection. This study aimed to analyse different surface antigens on T cells in a cohort of adult liver patients undergoing LT to determine the influence on ACR using multi-parametric flow cytometry functional assay. Thirty patients were monitored at baseline and during 1 year post-transplant. Two groups were established, with (ACR) and without (NACR) acute cellular rejection. Leukocyte, total lymphocyte, percentages of CD4+ CD154+ and CD8+ CD154+ T cells, human leukocyte antigen (HLA) mismatch between recipient-donor and their relation with ACR as well as the acute rejection frequencies were analysed. T cells were stimulated with concanavalin A (Con-A) and surface antigens were analysed by fluorescence activated cell sorter (FACS) analysis. A high percentage of CD4+ CD154+ T cells (P = 0·001) and a low percentage of CD8+ CD154+ T cells (P = 0·002) at baseline were statistically significant in ACR. A receiver operating characteristic analysis determined the cut-off values capable to stratify patients at high risk of ACR with high sensitivity and specificity for CD4+ CD154+ (P = 0·001) and CD8+ CD154+ T cells (P = 0·002). In logistic regression analysis, CD4+ CD154+ , CD8+ CD154+ and HLA mismatch were confirmed as independent risk factors to ACR. Post-transplant percentages of both T cell subsets were significantly higher in ACR, despite variations compared to pretransplant. These findings support the selection of candidates for LT based on the pretransplant percentages of CD4+ CD154+ and CD8+ CD154+ T cells in parallel with other transplant factors.

Frequency and Determinants of Inappropriate Use of Treadmill Stress Test for Coronary Artery Disease

Background In developing countries like Pakistan, treatment is mediated by private and public healthcare setups with a limited budget for health facilities. Moreover, the inappropriate use of treadmill tests imposes a burden on healthcare resources and leads to unwarranted interventions. Our aim is to assess the prevalence and predictors of inappropriate referrals for the exercise tolerance test (ETT) to diagnose coronary artery disease (CAD) while taking public and private healthcare settings into consideration. Methods A cross-sectional study was conducted to find the prevalence of the inappropriate use of ETT to diagnose obstructive CAD and to determine the factors responsible for it. A total of 264 patients were enrolled from outpatient departments in Karachi. The inclusion criterion was the referral of treadmill testing for the diagnosis of CAT. The analysis was performed by logistic regression models to ascertain independent predictors of inappropriate use. Results Exercise stress tests were found to be inappropriate in 209 (79%) patients. The study indicated that the majority of patients had a low or very low pre-test probability of CAD. Diabetes, hypertension, and dyslipidemia were less frequent in the inappropriate as compared to the appropriate referrals (10%, 45%, and 16% versus 20%, 69%, and 32%). Both public and private sectors showed a high prevalence of inappropriate testing, but it was much higher in the latter (27% versus 73%, P < 0.001). In all regression models, the private healthcare system was the major independent predictor for inappropriate indications of ETT with an average odds ratio of 4.9 (P < 0.001). Conclusion The high prevalence of ETT referrals was found for the diagnosis of CAD. This result was consistent with both public and private healthcare systems, but it was considerably higher in private setups. Comorbidities, number of risk factors, and cardiovascular risk were not associated with the inappropriate use of ETT.

Spinal cord compression in renal osteodystrophy

A patient undergoing regular haemodialysis for chronic renal insufficiency developed neck pain followed by progressive spinal cord compression due to subluxation at the level C3-4. Decompression, laminectomy and osteosynthesis led to an almost complete recovery. A review of all the histological specimens suggested that hyperparathyroidism and not amyloidosis caused the vertebral destruction.

Capsaicin-induced ion fluxes increase cyclic GMP but not cyclic AMP levels in rat sensory neurones in culture

Capsaicin, which induces fluxes of sodium, calcium, and potassium ions in a subset of both neonatal and adult rat dorsal root ganglion neurones, increased cyclic GMP (cGMP) levels by a factor of 20 (EC50 0.07 microM) to 10-20 pmol cGMP/mg protein in these cells. Cyclic AMP (cAMP) levels were unaffected. Nonneuronal cells derived from rat ganglia, and both neurones and nonneuronal cells from chick were unresponsive to capsaicin. Capsaicin-induced cGMP elevation in rat dorsal root ganglion (DRG) neurones was unaffected by pertussis toxin, lowered by compounds that block voltage-sensitive calcium channels, and was abolished by the removal of extracellular calcium. Calcium, guanidine, and rubidium fluxes were unaffected by treatment of DRG cells with sodium nitroprusside or dibutyryl cGMP. The cGMP response to capsaicin is thus a function of capsaicin-evoked calcium uptake through voltage-sensitive calcium channels. Elevated cGMP levels do not, however, contribute to capsaicin-evoked ion fluxes or to their desensitisation.

Activation of guanylate cyclase by bradykinin in rat sensory neurones is mediated by calcium influx: possible role of the increase in cyclic GMP

Bradykinin, which activates polymodal nociceptors, increased cyclic GMP (cGMP) in a capsaicin-sensitive population of cultured sensory neurones from rat dorsal root ganglia (DRG) by stimulating guanylate cyclase, but had no effect on cyclic AMP (cAMP). In nonneuronal cells from DRG, bradykinin increased cAMP, but not cGMP. The bradykinin-induced increase in cGMP in the neurones was completely blocked by removal of extracellular Ca2+, or by incubation of the cells with the calcium channel blockers nifedipine and verapamil. Pretreatment of the neurones with either dibutyryl cGMP or sodium nitroprusside (which elevates cGMP) inhibited bradykinin-induced formation of inositol phosphates. It is possible that cGMP could be involved in the regulation of polyphosphoinositide turnover in DRG neurones.