Counterpoint: should fibrinolytics be routinely administered intrapleurally for management of a complicated parapneumonic effusion? No

Thoracoscopic management of early stages of empyema: is this the golden standard?

Background

Empyema is a well-known disease that significantly increases the morbidity and mortality associated with pneumonia. There are a number of treatment modalities available but recently video assisted thoracoscopic surgery (VATS) has been suggested as a reliable tool in management of empyema; particularly in early stages. The aim of this study is to assess the safety and effectiveness of using initial VATS for all surgically fit patients with early stages of empyema.

Methods

Sixty-six patients with early stage empyema were prospectively studied between December 2013 and March 2016. Patients were divided into two groups: group A (28 patients) were managed conservatively without surgery for stage I (exudative) phase empyema by the chest physicians; and group B (38 patients) were managed by the thoracic surgeons by VATS for stage I (exudative) and stage II (fibrino-purulent) empyema. Comparison was made between both groups.

Results

There was no statistically significant difference between the groups from the point of view of age, sex or pre-intervention comorbidities (P>0.05). Average hospital stay in group A was 22 days (7-131 days), it was 4.1 days (2-14 days) in group B (P=0.004; 95% CI: 10.3-25.5) with a resultant lower cost. Three patients (10.7%) in group A suffered from major morbidity during treatment while none in group B suffered a major postoperative morbidity (P=0.039). There were 2 mortalities (7.1%) in group A and no deaths in group B (P=0.094). During a mean follow up period of 8 months [6-14] in group A 14.3% of the patients underwent open decortication, whereas in group B, 5.3% of the patients underwent the same procedure (P=0.047).

Conclusions

Thoracoscopic management of early stages of empyema should be the golden standard of management in surgically fit patients; particularly in the fibro-exudative phase of empyema. It is an effective and safe technique that reduces hospital stay, cost, complications and avoids the need for a decortication via a thoracotomy in most cases.

Inhibition of Glycogen Synthase Kinase 3β Blocks Mesomesenchymal Transition and Attenuates Streptococcus pneumonia-Mediated Pleural Injury in Mice

Pleural loculation affects about 30,000 patients annually in the United States and in severe cases can resolve with restrictive lung disease and pleural fibrosis. Pleural mesothelial cells contribute to pleural rind formation by undergoing mesothelial mesenchymal transition (MesoMT), whereby they acquire a profibrotic phenotype characterized by increased expression of α-smooth muscle actin and collagen 1. Components of the fibrinolytic pathway (urokinase plasminogen activator and plasmin) are elaborated in pleural injury and strongly induce MesoMT in vitro. These same stimuli enhance glycogen synthase kinase (GSK)-3β activity through increased phosphorylation of Tyr-216 in pleural mesothelial cells and GSK-3β mobilization from the cytoplasm to the nucleus. GSK-3β down-regulation blocked induction of MesoMT. Likewise, GSK-3β inhibitor 9ING41 blocked induction of MesoMT and reversed established MesoMT. Similar results were demonstrated in a mouse model of Streptococcus pneumoniae-induced empyema. Intraperitoneal administration of 9ING41, after the induction of pleural injury, attenuated injury progression and improved lung function (lung volume and compliance; P < 0.05 compared with untreated and vehicle controls). MesoMT marker α-smooth muscle actin was reduced in 9ING41-treated mice. Pleural thickening was also notably reduced in 9ING41-treated mice (P < 0.05). Collectively, these studies identify GSK-3β as a newly identified target for amelioration of empyema-related pleural fibrosis and provide a strong rationale for further investigation of GSK-3β signaling in the control of MesoMT and pleural injury.

Targeting plasminogen activator inhibitor-1 in tetracycline-induced pleural injury in rabbits

Elevated active plasminogen activator inhibitor-1 (PAI-1) has an adverse effect on the outcomes of intrapleural fibrinolytic therapy (IPFT) in tetracycline-induced pleural injury in rabbits. To enhance IPFT with prourokinase (scuPA), two mechanistically distinct approaches to targeting PAI-1 were tested: slowing its reaction with urokinase (uPA) and monoclonal antibody (mAb)-mediated PAI-1 inactivation. Removing positively charged residues at the "PAI-1 docking site" (¹⁷⁹RHRGGS¹⁸⁴→¹⁷⁹AAAAAA¹⁸⁴) of uPA results in a 60-fold decrease in the rate of inhibition by PAI-1. Mutant prourokinase (0.0625-0.5 mg/kg; n = 12) showed efficacy comparable to wild-type scuPA and did not change IPFT outcomes ( P > 0.05). Notably, the rate of PAI-1-independent intrapleural inactivation of mutant uPA was 2 times higher ( P < 0.05) than that of the wild-type enzyme. Trapping PAI-1 in a "molecular sandwich"-type complex with catalytically inactive two-chain urokinase with Ser¹⁹⁵Ala substitution (S195A-tcuPA; 0.1 and 0.5 mg/kg) did not improve the efficacy of IPFT with scuPA (0.0625-0.5 mg/kg; n = 11). IPFT failed in the presence of MA-56A7C10 (0.5 mg/kg; n = 2), which forms a stable intrapleural molecular sandwich complex, allowing active PAI-1 to accumulate by blocking its transition to a latent form. In contrast, inactivation of PAI-1 by accelerating the active-to-latent transition mediated by mAb MA-33B8 (0.5 mg/kg; n = 2) improved the efficacy of IPFT with scuPA (0.25 mg/kg). Thus, under conditions of slow (4-8 h) fibrinolysis in tetracycline-induced pleural injury in rabbits, only the inactivation of PAI-1, but not a decrease in the rate of its reaction with uPA, enhances IPFT. Therefore the rate of fibrinolysis, which varies in different pathologic states, could affect the selection of PAI-1 inhibitors to enhance fibrinolytic therapy.

Precision-guided, Personalized Intrapleural Fibrinolytic Therapy for Empyema and Complicated Parapneumonic Pleural Effusions: The Case for the Fibrinolytic Potential

Complicated pleural effusions and empyema with loculation and failed drainage are common clinical problems. In adults, intrapleural fibrinolytic therapy is commonly used with variable results and therapy remains empiric. Despite the intrapleural use of various plasminogen activators; fibrinolysins, for about sixty years, there is no clear consensus about which agent is most effective. Emerging evidence demonstrates that intrapleural administration of plasminogen activators is subject to rapid inhibition by plasminogen activator inhibitor-1 and that processing of fibrinolysins is importantly influenced by other factors including the levels and quality of pleural fluid DNA. Current therapy for loculation that accompanies pleural infections also includes surgery, which is invasive and for which patient selection can be problematic. Most of the clinical literature published to date has used flat dosing of intrapleural fibrinolytic therapy in all subjects but little is known about how that strategy influences the processing of the administered fibrinolysin or how this influences outcomes. We developed a new test of pleural fluids ex vivo, which is called the Fibrinolytic Potential or FP, in which a dose of a fibrinolysin is added to pleural fluids ex vivo after which the fibrinolytic activity is measured and normalized to baseline levels. Testing in preclinical and clinical empyema fluids reveals a wide range of responses, indicating that individual patients will likely respond differently to flat dosing of fibrinolysins. The test remains under development but is envisioned as a guide for dosing of these agents, representing a novel candidate approach to personalization of intrapleural fibrinolytic therapy.

Modified single-port non-intubated video-assisted thoracoscopic decortication in high-risk parapneumonic empyema patients

BACKGROUND

Parapneumonic empyema patients with coronary artery disease and reduced left ventricular ejection fraction are risky to receive surgical decortication under general anesthesia. Non-intubated video-assisted thoracoscopy surgery is successfully performed to avoid complications of general anesthesia. We performed single-port non-intubated video-assisted flexible thoracoscopy surgery in an endoscopic center. In this study, the possible role of our modified surgery to treat fibrinopurulent stage of parapneumonic empyema with high operative risks is investigated.

METHODS

We retrospectively reviewed fibrinopurulent stage of parapneumonic empyema patients between July 2011 and June 2014. Thirty-three patients with coronary artery disease and reduced left ventricular ejection fraction were included in this study. One group received tube thoracostomy, and the other group received single-port non-intubated video-assisted flexible thoracoscopy surgery decortication. Patient demographics, characteristics, laboratory findings, etiology, and treatment outcomes were compared.

RESULTS

Mean age of 33 patients (24 males, 9 females) was 76.2 ± 9.7 years. Twelve patients received single-port non-intubated video-assisted flexible thoracoscopy surgery decortication, and 21 patients received tube thoracostomy. Visual analog scale scores on postoperative first hour and first day were not significantly different in two groups (p value = 0.5505 and 0.2750, respectively). Chest tube drainage days, postoperative fever subsided days, postoperative hospital days, and total length of stay were significantly short in single-port non-intubated video-assisted flexible thoracoscopy surgery decortication (p value = 0.0027, 0.0001, 0.0009, and 0.0065, respectively). Morbidities were low, and mortality was significantly low (p value = 0.0319) in single-port non-intubated video-assisted flexible thoracoscopy surgery decortication.

CONCLUSIONS

Single-port non-intubated video-assisted flexible thoracoscopy surgery decortication may be suggested to be a method other than tube thoracostomy to deal with fibrinopurulent stage of parapneumonic empyema patients with coronary artery disease and reduced left ventricular ejection fraction.

Safety and Efficacy of Intrapleural Tissue Plasminogen Activator and DNase during Extended Use in Complicated Pleural Space Infections

The use of intrapleural therapy with tissue plasminogen activator and DNase improves outcomes in patients with complicated pleural space infections. However, little data exists for the use of combination intrapleural therapy after the initial dosing period of six doses. We sought to describe the safety profile and outcomes of intrapleural therapy beyond this standard dosing. A retrospective review of patients receiving intrapleural therapy with tissue plasminogen activator and DNase was performed at two institutions. We identified 101 patients from January 2013 to August 2015 receiving intrapleural therapy for complicated pleural space infection. The extended use of intrapleural tissue plasminogen activator and DNase therapy beyond six doses was utilized in 20% (20/101) of patients. The mean number of doses in those undergoing extended dosing was 9.8 (range of 7–16). Within the population studied there appears to be no statistically significant increased risk of complications, need for surgical referral, or outcome differences when comparing those receiving standard or extended dosing intrapleural therapy. Future prospective study of intrapleural therapy as an alternative option for patients who fail initial pleural drainage and are unable to tolerate/accept a surgical intervention appears a potential area of study.

Dose dependency of outcomes of intrapleural fibrinolytic therapy in new rabbit empyema models

The incidence of empyema (EMP) is increasing worldwide; EMP generally occurs with pleural loculation and impaired drainage is often treated with intrapleural fibrinolytic therapy (IPFT) or surgery. A number of IPFT options are used clinically with empiric dosing and variable outcomes in adults. To evaluate mechanisms governing intrapleural fibrinolysis and disease outcomes, models of Pasteurella multocida and Streptococcus pneumoniae were generated in rabbits and the animals were treated with either human tissue (tPA) plasminogen activator or prourokinase (scuPA). Rabbit EMP was characterized by the development of pleural adhesions detectable by chest ultrasonography and fibrinous coating of the pleura. Similar to human EMP, rabbits with EMP accumulated sizable, 20- to 40-ml fibrinopurulent pleural effusions associated with extensive intrapleural organization, significantly increased pleural thickness, suppression of fibrinolytic and plasminogen-activating activities, and accumulation of high levels of plasminogen activator inhibitor 1, plasminogen, and extracellular DNA. IPFT with tPA (0.145 mg/kg) or scuPA (0.5 mg/kg) was ineffective in rabbit EMP (n = 9 and 3 for P. multocida and S. pneumoniae, respectively); 2 mg/kg tPA or scuPA IPFT (n = 5) effectively cleared S. pneumoniae-induced EMP collections in 24 h with no bleeding observed. Although intrapleural fibrinolytic activity for up to 40 min after IPFT was similar for effective and ineffective doses of fibrinolysin, it was lower for tPA than for scuPA treatments. These results demonstrate similarities between rabbit and human EMP, the importance of pleural fluid PAI-1 activity, and levels of plasminogen in the regulation of intrapleural fibrinolysis and illustrate the dose dependency of IPFT outcomes in EMP.

Targeting of plasminogen activator inhibitor 1 improves fibrinolytic therapy for tetracycline-induced pleural injury in rabbits

Endogenous active plasminogen activator inhibitor 1 (PAI-1) was targeted in vivo with monoclonal antibodies (mAbs) that redirect its reaction with proteinases to the substrate branch. mAbs were used as an adjunct to prourokinase (single-chain [sc] urokinase [uPA]) intrapleural fibrinolytic therapy (IPFT) of tetracycline-induced pleural injury in rabbits. Outcomes of scuPA IPFT (0.25 or 0.0625 mg/kg) with 0.5 mg/kg of mouse IgG or mAbs (MA-33H1F7 and MA-8H9D4) were assessed at 24 hours. Pleural fluid (PF) was collected at 0, 10, 20, and 40 minutes and 24 hours after IPFT and analyzed for plasminogen activating (PA), uPA, fibrinolytic activities, levels of total plasmin/plasminogen, α-macroglobulin (αM), mAbs/IgG antigens, free active uPA, and αM/uPA complexes. Anti-PAI-1 mAbs, but not mouse IgG, delivered with an eightfold reduction in the minimal effective dose of scuPA (from 0.5 to 0.0625 mg/kg), improved the outcome of IPFT (P < 0.05). mAbs and IgG were detectable in PFs at 24 hours. Compared with identical doses of scuPA alone or with IgG, treatment with scuPA and anti-PAI-1 mAbs generated higher PF uPA amidolytic and PA activities, faster formation of αM/uPA complexes, and slower uPA inactivation. However, PAI-1 targeting did not significantly affect intrapleural fibrinolytic activity or levels of total plasmin/plasminogen and αM antigens. Targeting PAI-1 did not induce bleeding, and rendered otherwise ineffective doses of scuPA able to improve outcomes in tetracycline-induced pleural injury. PAI-1-neutralizing mAbs improved IPFT by increasing the durability of intrapleural PA activity. These results suggest a novel, well-tolerated IPFT strategy that is tractable for clinical development.

A case of Lemierre's syndrome with septic shock and complicated parapneumonic effusions requiring intrapleural fibrinolysis

Lemierre's syndrome is a septic thrombophlebitis of the internal jugular vein, which can lead to severe systemic illness. We report a case of an otherwise healthy 26-year-old man who suffered from pharyngitis followed by septic shock requiring intubation and vasopressor support from Fusobacterium necrophorum bacteremia. The septic emboli to his lungs caused complicated bilateral parapneumonic effusions, which recurred after initial drainage. He required bilateral chest tubes and intrapleural tPA to successfully drain his effusions. His fever curve and overall condition improved with the resolution of his effusions and after a 33-day hospitalization, he recovered without significant disability. The severity of his illness and difficult to manage complicated parapneumonic effusions were the unique facets of this case. Using an evidence-based approach of tPA and DNase for complicated parapneumonic effusions in Lemierre's syndrome can be safe and effective.