Biological effect of tissue plasminogen activator (t-PA) and DNase intrapleural delivery in pleural infection patients

Bleeding Risk With Combination Intrapleural Fibrinolytic and Enzyme Therapy in Pleural Infection: An International, Multicenter, Retrospective Cohort Study

BACKGROUND

Combination intrapleural fibrinolytic and enzyme therapy (IET) has been established as a therapeutic option in pleural infection. Despite demonstrated efficacy, studies specifically designed and adequately powered to address complications are sparse. The safety profile, the effects of concurrent therapeutic anticoagulation, and the nature and extent of nonbleeding complications remain poorly defined.

RESEARCH QUESTION

What is the bleeding complication risk associated with IET use in pleural infection?

STUDY DESIGN AND METHODS

This was a multicenter, retrospective observational study conducted in 24 centers across the United States and the United Kingdom. Protocolized data collection for 1,851 patients treated with at least one dose of combination IET for pleural infection between January 2012 and May 2019 was undertaken. The primary outcome was the overall incidence of pleural bleeding defined using pre hoc criteria.

RESULTS

Overall, pleural bleeding occurred in 76 of 1,833 patients (4.1%; 95% CI, 3.0%-5.0%). Using a half-dose regimen (tissue plasminogen activator, 5 mg) did not change this risk significantly (6/172 [3.5%]; P = .68). Therapeutic anticoagulation alongside IET was associated with increased bleeding rates (19/197 [9.6%]) compared with temporarily withholding anticoagulation before administration of IET (3/118 [2.6%]; P = .017). As well as systemic anticoagulation, increasing RAPID score, elevated serum urea, and platelets of < 100 × 10⁹/L were associated with a significant increase in bleeding risk. However, only RAPID score and use of systemic anticoagulation were independently predictive. Apart from pain, non-bleeding complications were rare.

INTERPRETATION

IET use in pleural infection confers a low overall bleeding risk. Increased rates of pleural bleeding are associated with concurrent use of anticoagulation but can be mitigated by withholding anticoagulation before IET. Concomitant administration of IET and therapeutic anticoagulation should be avoided. Parameters related to higher IET-related bleeding have been identified that may lead to altered risk thresholds for treatment.

Nonmalignant Pleural Effusions

Although the potential causes of nonmalignant pleural effusions are many, the management of a few, including complicated pleural infections and refractory heart failure and hepatic hydrothoraces, can be challenging and requires the assistance of interventional pulmonologists. A pragmatic approach to complicated parapneumonic effusions or empyemas is the insertion of a small-bore chest tube (e.g., 14-16 Fr) through which fibrinolytics (e.g., urokinase and alteplase) and DNase are administered in combination. Therapeutic thoracenteses are usually reserved for small to moderate effusions that are expected to be completely aspirated at a single time, whereas video-assisted thoracic surgery should be considered after failure of intrapleural enzyme therapy. Refractory cardiac and liver-induced pleural effusions portend a poor prognosis. In cases of heart failure-related effusions, therapeutic thoracentesis is the first-line palliative therapy. However, if it is frequently needed, an indwelling pleural catheter (IPC) is recommended. In patients with hepatic hydrothorax, repeated therapeutic thoracenteses are commonly performed while a multidisciplinary decision on the most appropriate definitive management is taken. The percutaneous creation of a portosystemic shunt may be used as a bridge to liver transplantation or as a potential definitive therapy in nontransplant candidates. In general, an IPC should be avoided because of the high risk of complications, particularly infections, that may jeopardize candidacy for liver transplantation. Even so, in noncandidates for liver transplant or surgical correction of diaphragmatic defects, IPC is a therapeutic option as valid as serial thoracenteses.

Modified regimen intrapleural alteplase with pulmozyme in pleural infection management: a tertiary teaching hospital experience

Background

Current management of poorly draining complex effusions favours less invasive image-guided placement of smaller tubes and adjunctive intrapleural fibrinolysis therapy (IPFT). In MIST-2 trial, intrapleural 10 mg alteplase (t-PA) with 5 mg of pulmozyme (DNase) twice daily for 72 h were used. We aimed to assess the effectiveness and safety of a modified regimen 16 mg t-PA with 5 mg of DNase administered over 24 h in the management of complex pleural infection.

Methods

This was a single centre, prospective study involving patients with poorly drained pleural infection. Primary outcome was the change of pleural opacity on chest radiograph at day 7 compared to baseline. Secondary outcomes include volume of fluid drained, inflammatory markers improvement, surgical referral, length of hospitalisation, and adverse events.

Results

Thirty patients were recruited. Majority, 27 (90%) patients were successfully treated. Improvement of pleural opacity on chest radiograph was observed from 36.9% [Interquartile range (IQR 21.8–54.9%)] to 18.1% (IQR 8.8–32.7%) of hemithorax (P < 0.05). T-PA/DNase increased fluid drainage from median of 45 mls (IQR 0–100) 24 h prior to intrapleural treatment to 1442 mls (IQR 905–2360) after 72 h; (P < 0.05) and reduction of C-reactive protein (P < 0.05). Pain requiring escalation of analgesia affected 20% patients and 9.9% experienced major adverse events. None required surgical intervention.

Conclusion

This study suggests that a modified regimen 16 mg t-PA with 5 mg DNase can be safe and effective for patients with poorly drained complex pleural infection.

Trial registration The study was registered retrospectively on 07/06/2021 with ClinicalTrials number NCT04915586 (https://clinicaltrials.gov/ct2/show/NCT04915586).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01995-z.

From Bedside to the Bench—A Call for Novel Approaches to Prognostic Evaluation and Treatment of Empyema

Empyema, a severe complication of pneumonia, trauma, and surgery is characterized by fibrinopurulent effusions and loculations that can result in lung restriction and resistance to drainage. For decades, efforts have been focused on finding a universal treatment that could be applied to all patients with practice recommendations varying between intrapleural fibrinolytic therapy (IPFT) and surgical drainage. However, despite medical advances, the incidence of empyema has increased, suggesting a gap in our understanding of the pathophysiology of this disease and insufficient crosstalk between clinical practice and preclinical research, which slows the development of innovative, personalized therapies. The recent trend towards less invasive treatments in advanced stage empyema opens new opportunities for pharmacological interventions. Its remarkable efficacy in pediatric empyema makes IPFT the first line treatment. Unfortunately, treatment approaches used in pediatrics cannot be extrapolated to empyema in adults, where there is a high level of failure in IPFT when treating advanced stage disease. The risk of bleeding complications and lack of effective low dose IPFT for patients with contraindications to surgery (up to 30%) promote a debate regarding the choice of fibrinolysin, its dosage and schedule. These challenges, which together with a lack of point of care diagnostics to personalize treatment of empyema, contribute to high (up to 20%) mortality in empyema in adults and should be addressed preclinically using validated animal models. Modern preclinical studies are delivering innovative solutions for evaluation and treatment of empyema in clinical practice: low dose, targeted treatments, novel biomarkers to predict IPFT success or failure, novel delivery methods such as encapsulating fibrinolysin in echogenic liposomal carriers to increase the half-life of plasminogen activator. Translational research focused on understanding the pathophysiological mechanisms that control 1) the transition from acute to advanced-stage, chronic empyema, and 2) differences in outcomes of IPFT between pediatric and adult patients, will identify new molecular targets in empyema. We believe that seamless bidirectional communication between those working at the bedside and the bench would result in novel personalized approaches to improve pharmacological treatment outcomes, thus widening the window for use of IPFT in adult patients with advanced stage empyema.

Advances in pleural infection and malignancy

Pleural infection and malignancy are among the most common causes of pleural disease and form the mainstay of pleural practice. There has been significant research and increase in scientific understanding in these areas in the past decade. With regard to pleural infection, the rising incidence remains worrying. An increased awareness allowing earlier diagnosis, earlier escalation of therapy and the use of validated risk stratification measures may improve outcomes. In pleural malignancy, research has enabled clinicians to streamline patient pathways with focus on reducing time to diagnosis, definitive management of malignant pleural effusion and achieving these with the minimum number of pleural interventions. Trials comparing treatment modalities of malignant pleural effusion continue to highlight the importance of patient choice in clinical decision-making. This article aims to summarise some of the most recent literature informing current practice in these two areas.

Use of fibrinolytics and deoxyribonuclease in adult patients with pleural empyema: a consensus statement

Although our understanding of the pathogenesis of empyema has grown tremendously over the past few decades, questions still remain on how to optimally manage this condition. It has been almost a decade since the publication of the MIST2 trial, but there is still an extensive debate on the appropriate use of intrapleural fibrinolytic and deoxyribonuclease therapy in patients with empyema. Given the scarcity of overall guidance on this subject, we convened an international group of 22 experts from 20 institutions across five countries with experience and expertise in managing adult patients with empyema. We did a literature and internet search for reports addressing 11 clinically relevant questions pertaining to the use of intrapleural fibrinolytic and deoxyribonuclease therapy in adult patients with bacterial empyema. This Position Paper, consisting of seven graded and four ungraded recommendations, was formulated by a systematic and rigorous process involving the evaluation of published evidence, augmented with provider experience when necessary. Panel members participated in the development of the final recommendations using the modified Delphi technique. Our Position Paper aims to address the existing gap in knowledge and to provide consensus-based recommendations to offer guidance in clinical decision making when considering the use of intrapleural therapy in adult patients with bacterial empyema.