Higher incidence of stroke in severe COVID-19 is not associated with a higher burden of arrhythmias: comparison to other types of severe pneumonia

Background

Thromboembolic events, including stroke, are typical complications of COVID-19. Whether arrhythmias, frequently described in severe COVID-19, are disease-specific and thus promote strokes is unclear. We investigated the occurrence of arrhythmias, and stroke during rhythm monitoring in critically ill COVID-19, compared to severe pneumonias of other origin.

Methods

Recruited were 120 critically ill patients requiring mechanical ventilation in three European tertiary hospitals, including n=60 COVID-19, matched according to risk factors for occurrence of arrhythmias to n=60 patients from a retrospective consecutive cohort of severe pneumonias of other origin.

Results

Arrhythmias, mainly atrial fibrillation (AF), were frequent in COVID-19. However, when compared to nonCOVID-19, no difference was observed with respect to ventricular tachycardias (VT) and relevant bradyarrhythmias (VT 10.0 vs. 8.4%, p=ns and asystole 5.0 vs. 3.3%, p=ns) with consequent similar rates of cardiopulmonary resuscitation (6.7 vs. 10.0% p=ns). AF was even more common in nonCOVID-19 (AF 18.3 vs. 43.3%, p=0.003; newly onset AF 10.0 vs. 30.0%, p=0.006) which resulted in higher need for electrical cardioversion (6.7 vs. 20.0%, p=0.029). Despite these findings and comparable rates of therapeutic anticoagulation (TAC), the incidence of stroke was higher in COVID-19 (6.7.% vs. 0.0, p=0.042). These events happened also in absence of AF (50%) and with TAC (50%).

Conclusion

Arrhythmias were common in severe COVID-19, consisting mainly of AF, yet less frequent than in matched pneumonias of other origin. A contrasting higher incidence of stroke independent of arrhythmias observed also with TAC, seems to be an arrhythmia-unrelated disease-specific feature of COVID-19.

Funding Acknowledgement

Type of funding sources: None.

Lipid profile in cardiac transplantation: a closer look at bad cholesterol

Background

When it comes to lipid-lowering therapy, the primary goal is still to reduce the low-density lipoprotein levels. Although remnant cholesterol (RC), including predominantly intermediate- and very-low-density lipoproteins, is a known cardiovascular risk factor, reliable reference values, as well as therapy strategies, are yet to be validated. Additionally, the role of RC after heart transplantation is still unclear.

Aim

To assess the clinical and prognostic relevance of lipid profile and, in particular, of remnant cholesterol in very long-term follow-up after HTx.

Methods

We performed a retrospective analysis of the clinical and laboratory parameters collected at last follow-up in an outpatient setting. Additionally, remnant cholesterol levels were estimated using the formula (in mg/dL): remnant cholesterol = total cholesterol – (HLD-C + LDL-C).

Results

Out of 174 patients with a mean age of 45.2±15.0 years at the time of HTx and a mean follow-up of 13.1±6.5 years, 142 (81.6%) were on statin treatment. Mean cholesterol level was borderline high (184.1±48.4 mg/dL), whereas mean LDL and triglyceride values were markedly elevated (103.6±39.2 and 161.8±83.8 mg/dL, respectively). HDL results were found to be 57.1±17.5 mg/dL. Statin treatment was associated with significantly lower LDL levels (124.6±53.5 vs. 98.8±33.6 mg/dL on statins, p=0.013), but failed to show prognostic relevance in a univariate cox-regression analysis (HR 0.79, 95% CI 0.37 – 1.72, p=0.57). RC was elevated in comparison to the background population with a mean level of 23.5±17.3 mg/dL (24.2±18.1 in male and 21.3±14.8 mg/dL in female) and a tendency for lower values when on treatment with statins but without statistical significance (28.5±19.2 vs. 22.3±16.8 mg/dL on statins, p=0.07). Treatment with higher doses of statins showed no relevant influence on the RC levels (p=0.62). Additionally, elevated RC was associated with higher C-reactive protein values as a sign of systemic inflammation (CRP >0.5 mg/dL, OR 1.1, 95% CI 1.007 – 1.046, p=0.007). In a multivariate cox-regression analysis (adjusted for total cholesterol, LDL and triglycerides) RC was identified as a significant factor influencing mortality (HR 1.11, 95% CI 1.05 – 1.17, p<0.001).

Conclusions

When addressing dyslipidaemia in heart transplantation, statin therapy can help reduce LDL levels, but this approach seems to be insufficient in achieving clinical benefit. Remnant cholesterol is a factor, which has proinflammatory properties and can potentially influence the prognosis in HTx. The possible therapeutic alternatives for this overseen component of the lipid profile are yet to be elucidated.

Funding Acknowledgement

Type of funding sources: None.

Immunological monitoring in cardiac allograft vasculopathy

Background

The interaction of immunological determinants and classic cardiovascular risk factors can accelerate the development of cardiac allograft vasculopathy (CAV) with deleterious consequences for the graft function in heart transplantation (HTx). When it comes to immunological risk assessment, inverse CD4/CD8 ratio can be a poor prognostic marker in coronary artery disease, but its influence is unclear in CAV.

Aim

To evaluate the role of the T-lymphocyte count in peripheral blood as well as CD4/CD8 ratio as a predictive marker for CAV severity in a very long-term follow-up after HTx.

Methods

We performed a retrospective analysis of patient data collected during routine clinical follow-up visits. These data included innate and adaptive immune cell count in peripheral blood (lymphocyte count, CD3+, CD4+, CD8+ and CD19+ T cells and NK cells).

Results

The study population consisted of 174 patients with a mean follow-up of 13.1±6.5 years and a mean age at the time of HTx of 45.2±15.0 years. CAV was diagnosed in 71 patients (40.8%), more than half of which underwent interventional procedure or surgical therapy (n=40, 56.3%). A comparison of the cytoimmunological profile of patients with no CAV or mild disease (group 1, n=134) vs. with CAV requiring treatment (group 2, n=40), revealed significantly reduced percentage of CD4+ T cells (46.4±11.4% vs. 41.2±9.6%, p=0.01) and elevated percentage of CD8+ T lymphocytes in group 2 (28.3±14.1% vs. 35.8±13.7%, p=0.003). Thus, the CD4/CD8 ratio was altered in therapy requiring CAV (2.3±2.0 vs. 1.5±1.0, respectively, p<0.001). However, we observed no differences in the absolute count of T-helper cells (CD4+ T cells: 692.2±329.2 vs. 653.8±390.5 cells/μL, p=0.54) and cytotoxic T lymphocytes (CD8+ T cells: 474.7±450.2 vs. 600.0±469.0 cells/μL, p=0.13). Further analysis showed no differences regarding lymphocyte count and absolute count or percentage of CD3+ and CD19+ T cells as well as NK cells. Inverse CD4/CD8 ratio (<1) was associated with greater risk for therapy requiring CAV (OR 2.8, 95% CI 1.3 – 5.9, p=0.009) in a univariate logistic regression analysis.

Conclusions

Decreased CD4+ T cell count along with increased cytotoxic T lymphocyte count resulting in inverse CD4/CD8 ratio is associated with increased CAV severity in HTx. Given the possible interactions with the immunosuppressive agents and prednisolone, monitoring of the cytomimmunological profile can help identify patients at risk and be useful in establishing therapeutic strategies.

Funding Acknowledgement

Type of funding sources: None.

Renal graft outcome in combined heart-kidney transplantation compared to kidney transplantation alone: a single-center, matched-control study

BACKGROUND

Renal allograft outcome in heart-kidney transplantation (HKTx) might be affected by hemodynamic instability and high levels of calcineurin inhibitor-dependent immunosuppression.

METHODS

From November 1999 to March 2008, 13 patients who received HKTx were compared with a matched control group of 13 kidney transplantation (KTx) recipients with similar cardiovascular risk factors. Graft function, rejection periods, and patient survival were analyzed.

RESULTS

Renal allograft rejection was noted in three patients (23%) after HKTx and in four patients (31%) after KTx. Serum creatinine levels were comparable at 1 week, 1 month, 1, 2, and 3 years after transplantation. Patient survival rates at 1, 2, and 3 years were 100% for HKTx recipients and 100, 92, and 92% for isolated KTx patients. Graft survival was 92% at 1, 2, and 3 years after HKTx and 100% at 1 year and 92% at 2 and 3 years after isolated KTx.

CONCLUSIONS

Our results with excellent long-term graft function and survival after combined HKTx indicate that this procedure is a valuable option for a growing number of patients suffering from coexistent cardiac and renal failure.

Pulmonary Palacos embolism: a case report

Instrumentation with cement-augmented pedicle screws has expanded the therapeutic spectrum. This technique is useful for the palliation of bone metastases and in generalized osteoporosis. Serious complications such as pulmonary embolism have been described following percutaneous vertebroplasty, a frequently used technique. We report the case of a 55-year-old patient with a large central Palacos embolism of the right pulmonary artery after corporectomy of the lumbar vertebrae 3 and 4 and reconstruction using autologous pelvic bone. The large Palacos embolism was removed successfully from the right pulmonary artery with extracorporeal circulation.

Radiofrequency energy modification of the atrioventricular junction in patients with atrial fibrillation: modes of ventricular response under autonomic blockade and long-term effect

The short- and long-term effect of radiofrequency (RF) modification of the AV junction on ventricular rate and left ventricular function and the different types of ventricular response during energy application under autonomic nervous blockade were assessed in 28 patients with medically refractory atrial fibrillation. During the successful RF application, ventricular rate slowed progressively (type I response, ten patients) or accelerated at first and then slowed (type II response, 11 patients). Type II response was associated with a more anterior ablation site compared to Type I response. A primary successful outcome was achieved in 21 patients. Inadvertent complete AV block developed in three patients, while in four patients AV nodal ablation was performed after an unsuccessful modification attempt. During 6-month follow-up, the ventricular rate was adequately controlled in only four patients. Among the 16 patients with a recurrence of uncontrolled AF were all 10 patients with type I response and 6 of 11 patients with type II response. One patient died suddenly 10 weeks after the procedure.

Sequence-specific antiproliferative effects of antisense and end-capping-modified antisense oligodeoxynucleotides targeted against the 5'-terminus of basic-fibroblast-growth-factor mRNA in coronary smooth muscle cells

Basic fibroblast growth factor (bFGF), a potent mitogen for arterial smooth muscle cells, has been shown to play a fundamental role in the pathogenesis of arteriosclerosis and restenosis by stimulating the proliferation of vascular smooth muscle cells. We found that partially phosphorothioate-modified 15-residue antisense oligodeoxynucleotides complementary to bFGF mRNA at 0.1-2.0 microM block growth and division of cultured human and bovine coronary smooth muscle cells in a dose-dependent manner. The effect is sequence specific at low (0.1-0.5 microM) nontoxic concentrations. It is associated with inhibition of expression of pericellular and intracellular bFGF, with a decreased de novo synthesis of bFGF and is partly reversible by the addition of exogenous (recombinant) bFGF. The antisense effect lasts 48-72 h and diminishes thereafter. If the antisense oligodeoxynucleotide medium is replaced by an oligonucleotide-free medium after 24 h, the [3H]thymidine incorporation rate returns to control levels. Under the same conditions, the corresponding sense oligodeoxynucleotide exerts negligible nonspecific inhibitory actions. The antiproliferative potency of the 15-residue antisense oligodeoxynucleotide is markedly enhanced by adding 3-4 nonbase-pairing guanosine residues at the 5'- and 3'-termini of the 15-residue antisense oligonucleotide. The data implicate bFGF in the process of smooth muscle cell proliferation and an effective and specific antiproliferative potency of bFGF-specific antisense oligonucleotides. The results point to possible new therapeutic strategies for the use of antisense methodology in the suppression of post-angioplasty restenosis.

A simple method for the flow cytometric analysis of intracellular antigens in whole smooth muscle cells: quantification of cyclin-dependent kinase 2

Flow cytometry has become a widely used technique for the quantitative analysis of antigens at the single cell level. In the past, several protocols have been published for the detection of cytoplasmic and nuclear antigens in various cell lines, especially blood cells or cells growing in fluid culture. The applicability of these protocols to cells growing in a monolayer, such as smooth muscle cells (SMC) is often restricted, although flow cytometry is of great interest in the fields of arteriosclerosis and cancer research. We here describe a simple and reproducible method for the flow cytometric analysis of intracellular antigens such as cyclin-dependent kinase 2 (Cdk2) in rat aortic SMC. The sensitivity of the method was analyzed under growth and growth-inhibitory conditions using lovastatin, a cholesterol-lowering compound with antiproliferative capacity. Various antigens (Ras-protein, protein kinase C-alpha (PKC-alpha), Ki-67/MIB-1) in rat and bovine SMC were detectable using this methodology which should have a wide range of applications.

Investigations of the lymphokine system in elderly individuals

Elderly people are at risk from an increased incidence of infections. Therefore we have studied the correlation between the production of several immunological parameters such as interferon-gamma (IFN-gamma), interferon-alpha-2 (IFN-alpha-2), interleukin-2 (IL-2), soluble interleukin-2 receptors (sIL-2R) and interleukin-6 (IL-6) in young controls of 25-34 years old and old individuals with a minimum age of 65 years. All persons were selected according to the basic concept of the 'Senieur protocol'. Heparinized blood was taken and cultured in the whole-blood assay. The determination of all cytokines in the supernatants of stimulated cultures was done by the ELISA technique. We found significantly decreased levels of sIL-2R and IFN-alpha-2 after stimulation, whereas the values of IFN-gamma and IL-2 showed no significant difference between elderly and young persons. The values of IL-6 showed a distinct trend towards an increased synthesis for the elderly. We also studied the lymphocyte subpopulations T4 and T8 by flow cytometry. Elderly individuals showed a significantly increased T4/T8 ratio, caused by a slightly but not significantly decreased level of T8 cells. These results show that the elderly have decreased values of some immunological parameters such as IFN-alpha-2 and sIL-2R, which might explain an increased susceptibility of elderly individuals to bacterial and viral infections.

Macrophage colony-stimulating factor (CSF-1) is expressed by spontaneously outgrown EBV-B cell lines and activated normal B lymphocytes

Human B lymphocytes activated by mitogens or infected by Epstein Barr virus (EBV) have previously been shown to release colony-stimulating activity (CSA) supporting the growth of normal human bone marrow progenitors. We established five different human EBV-B cell lines spontaneously outgrown from nonmalignant peripheral blood cells and long-term bone marrow cultures. CSA derived from all of these lines induces the growth of murine macrophage colonies, whereas virtually no human bone marrow cell progenitors were stimulated. As observed in the tumor cell line MIA PaCa-2, a 4.3-kilobase (kb) transcript was detected in all cases using a human colony-stimulating factor (CSF)-1 probe. Expression of this transcript can be further stimulated within three hours upon addition of phorbol myristate acetate (PMA). The highly purified native protein exerting macrophage colony-stimulating activity (M-CSA) exhibits a molecular size of approximately 75 to 97 Kd in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The identity of EBV-B cell derived M-CSA with human urinary CSF-1 was confirmed by a complete neutralization of macrophage CSA by an antihuman urinary CSF-1 antiserum. Normal human B lymphocytes purified from tonsils or from mononuclear blood cells also express CSF-1 upon stimulation with Staphylococcus aureus Cowan I. No CSF-1 expression, however, could be detected in normal resting B lymphocytes or in the Burkitt lymphoma cell line RAJI.