Herpes Virus Infection in Lung Transplantation: Diagnosis, Treatment and Prevention Strategies.

Lung transplantation is an ultimate treatment option for some end-stage lung diseases; due to the intense immunosuppression needed to reduce the risk of developing acute and chronic allograft failure, infectious complications are highly incident. Viral infections represent nearly 30% of all infectious complications, with herpes viruses playing an important role in the development of acute and chronic diseases. Among them, cytomegalovirus (CMV) is a major cause of morbidity and mortality, being associated with an increased risk of chronic lung allograft failure. Epstein-Barr virus (EBV) is associated with transformation of infected B cells with the development of post-transplantation lymphoproliferative disorders (PTLDs). Similarly, herpes simplex virus (HSV), varicella zoster virus and human herpesviruses 6 and 7 can also be responsible for acute manifestations in lung transplant patients. During these last years, new, highly sensitive and specific diagnostic tests have been developed, and preventive and prophylactic strategies have been studied aiming to reduce and prevent the incidence of these viral infections. In this narrative review, we explore epidemiology, diagnosis and treatment options for more frequent herpes virus infections in lung transplant patients.

Five-Year Outcome After Continuous Flow LVAD With Full-Magnetic (HeartMate 3) Versus Hybrid Levitation System (HeartWare): A Propensity-Score Matched Study From an All-Comers Multicentre Registry.

Despite the withdrawal of the HeartWare Ventricular Assist Device (HVAD), hundreds of patients are still supported with this continuous-flow pump, and the long-term management of these patients is still under debate. This study aims to analyse 5 years survival and freedom from major adverse events in patients supported by HVAD and HeartMate3 (HM3). From 2010 to 2022, the MIRAMACS Italian Registry enrolled all-comer patients receiving a LVAD support at seven Cardiac Surgery Centres. Out of 447 LVAD implantation, 214 (47.9%) received HM3 and 233 (52.1%) received HVAD. Cox-regression analysis adjusted for major confounders showed an increased risk for mortality (HR 1.5 [1.2-1.9]; p = 0.031), for both ischemic stroke (HR 2.08 [1.06-4.08]; p = 0.033) and haemorrhagic stroke (HR 2.6 [1.3-4.9]; p = 0.005), and for pump thrombosis (HR 25.7 [3.5-188.9]; p < 0.001) in HVAD patients. The propensity-score matching analysis (130 pairs of HVAD vs. HM3) confirmed a significantly lower 5 years survival (81.25% vs. 64.1%; p 0.02), freedom from haemorrhagic stroke (90.5% vs. 70.1%; p < 0.001) and from pump thrombosis (98.5% vs. 74.7%; p < 0.001) in HVAD cohort. Although similar perioperative outcome, patients implanted with HVAD developed a higher risk for mortality, haemorrhagic stroke and thrombosis during 5 years of follow-up compared to HM3 patients.

Lung Transplantation for Primary Ciliary Dyskinesia and Kartagener Syndrome: A Multicenter Study.

Primary ciliary dyskinesia, with or without situs abnormalities, is a rare lung disease that can lead to an irreversible lung damage that may progress to respiratory failure. Lung transplant can be considered in end-stage disease. This study describes the outcomes of the largest lung transplant population for PCD and for PCD with situs abnormalities, also identified as Kartagener's syndrome. Retrospectively collected data of 36 patients who underwent lung transplantation for PCD from 1995 to 2020 with or without SA as part of the European Society of Thoracic Surgeons Lung Transplantation Working Group on rare diseases. Primary outcomes of interest included survival and freedom from chronic lung allograft dysfunction. Secondary outcomes included primary graft dysfunction within 72 h and the rate of rejection ≥A2 within the first year. Among PCD recipients with and without SA, the mean overall and CLAD-free survival were 5.9 and 5.2 years with no significant differences between groups in terms of time to CLAD (HR: 0.92, 95% CI: 0.27-3.14, p = 0.894) or mortality (HR: 0.45, 95% CI: 0.14-1.43, p = 0.178). Postoperative rates of PGD were comparable between groups; rejection grades ≥A2 on first biopsy or within the first year was more common in patients with SA. This study provides a valuable insight on international practices of lung transplantation in patients with PCD. Lung transplantation is an acceptable treatment option in this population.

A multicentric evaluation of pediatric lung transplantation in Italy.

BACKGROUND: Pediatric lung transplantation is performed in highly experienced centers due to the peculiar population characteristics. The literature is limited and not representative of individual countries' differences. The purpose of this study was to analyze the Italian experience. METHODS: A multicentric retrospective analysis was performed on 110 pediatric patients (<18 years old) who underwent lung transplantation from 1992 to 2019 at 9 Italian centers. Heart-lung transplantations and lung retransplantations were excluded. RESULTS: The population was composed of 44 male and 66 female patients, with a median age of 15 years. The most frequent indication was cystic fibrosis (83%). One quarter of patients were transplanted in an emergency setting. Median donors' Oto score and age were 1 and 15 years, respectively, with 43% of adult donors. In 17% of patients a graft reduction was performed. Postoperatively, the median duration of mechanical ventilation, intensive care unit, and in-hospital stay were 48 hours, 11 and 35 days, respectively. Thirty-day mortality was 6%, and 1-, 5-, and 10-year survival was 72%, 52%, and 33%, respectively. Risk factors for mortality were Oto score and recipients' body mass index. CONCLUSIONS: The outcomes of pediatric lung transplantation in Italy are comparable with current literature. Particular attention should be paid to the Oto score and recipient body mass index. Conversely, adult donors and graft reductions can be safely used to expand the donor pool.

Single-Dose St. Thomas Versus Custodiol® Cardioplegia for Right Mini-thoracotomy Mitral Valve Surgery.

OBJECTIVE: Custodiol® and St. Thomas cardioplegia are widely employed in mini-thoracotomy mitral valve (MV) operations. One-dose of the former provides 3 h of myocardial protection. Conversely, St. Thomas solution is usually reinfused every 30 min and safety of single delivery is unknown. We aimed to compare single-shot St. Thomas versus Custodiol® cardioplegia. METHODS: Primary endpoint of the prospective observational study was cardiac troponin T level at different post-operative time-points. Propensity-weighted treatment served to adjust for confounding factors. RESULTS: Thirty-nine patients receiving St. Thomas were compared with 25 patients receiving Custodiol® cardioplegia; cross-clamping always exceeded 45 min. No differences were found in postoperative markers of myocardial injury. Ventricular fibrillation at the resumption of electric activity was more frequent following Custodiol® cardioplegia (P = .01). CONCLUSION: Effective myocardial protection exceeding 1 h of ischemic arrest can be achieved with a single-dose St. Thomas cardioplegia in selected patients undergoing right mini-thoracotomy MV surgery.

Antegrade Perfusion for Mini-Thoracotomy Mitral Valve Surgery in Patients with Atherosclerotic Burden.

BACKGROUND: The relationship between retrograde arterial perfusion and stroke in patients with peripheral vascular disease has been widely documented. Antegrade arterial perfusion has been favoured as an alternative approach in less invasive mitral valve (MV) operations. We aimed to analyse our experience in patients with peripheral arterial disease undergoing MV surgery through a right mini-thoracotomy adopting antegrade arterial perfusion. METHOD: A single-institution retrospective study on prospectively collected data was performed on patients undergoing right mini-thoracotomy MV surgery with antegrade arterial perfusion. Since 2009, indication for the latter was dictated by the severity of atherosclerotic burden. Preoperative screening included computed tomography, angiography, or both for the evaluation of the aorta and ileo-femoral arteries. RESULTS: Consecutive patients (n=117) underwent MV surgery through a right mini-thoracotomy with antegrade arterial perfusion, established either by transthoracic central aortic cannulation in 65 (55.6%) cases or by axillary arterial cannulation in 52 (44.4%). Mean logistic EuroSCORE was 11%±2.3%. Twenty-five (25) (21.4%) patients had undergone one or more previous cardiac operations. Operative mortality was 4.3% (n=5). Nonfatal iatrogenic aortic dissection occurred in one case (0.8%). The incidence of stroke was zero. CONCLUSIONS: Axillary or central aortic cannulation is a promising alternative route to provide excellent arterial perfusion in right mini-thoracotomy MV surgery, with a very low incidence of stroke and other major perioperative complications in patients with severe aortic or peripheral arterial disease.

Magnetic Resonance Imaging for Cerebral Micro-embolizations During Minimally Invasive Mitral Valve Surgery.

The role of aortic clamping techniques on the occurrence of neurological complications after right mini-thoracotomy mitral valve surgery is still debated. Brain injuries can occur also as silent cerebral micro-embolizations (SCM), which have been linked to significant deficits in physical and cognitive functions. Aims of this study are to evaluate the overall rate of SCM and to compare endoaortic clamp (EAC) with trans-thoracic clamp (TTC). Patients enrolled underwent a pre-operative, a post-operative, and a follow-up MRI. Forty-three patients were enrolled; EAC was adopted in 21 patients, TTC in 22 patients. Post-operative SCM were reported in 12 cases (27.9%). No differences between the 2 groups were highlighted (23.8% SCM in the EAC group versus 31.8% in the TTC). MRI analysis showed post-operative SCM in nearly 30% of selected patients after right mini-thoracotomy mitral valve surgery. Subgroup analysis on different types of aortic clamping showed comparable results. CLINICAL RELEVANCE: The rate of SCM reported in the present study on patients undergoing minimally invasive MVS and RAP is consistent with data in the literature on patients undergoing cardiac surgery through median sternotomy and antegrade arterial perfusion. Moreover, no differences were reported between EAC and TTC: both the aortic clamping techniques are safe, and the choice of the surgical setting to adopt can be really done according to the patient's characteristics.

Nodular Cutaneous Lesions in Immune-Compromised Hosts as a Clue for the Diagnosis of Disseminated Nocardiosis: From Bedside to Microbiological Identification.

BACKGROUND: Nocardia is a group of ubiquitous bacteria known to cause opportunistic infections in immunocompromised hosts, including those affected by malignancies and solid-organ or hematopoietic stem cell transplants. Pulmonary involvement, occurring in two-thirds of cases, is the most frequent presentation. Diagnosis might be challenging both because of microbiological technical issues, but also because of the variability of organ involvement and mimicry. METHODS: We describe four cases of disseminated nocardiosis caused by N. farcinica observed between September 2021 and November 2021 in immune-compromised hosts presenting with nodular cutaneous lesions that had raised a high degree of clinical suspect and led to microbiological identification through MALDI-TOF MS. RESULTS: Cutaneous involvement is typically reported in immunocompetent hosts with primary cutaneous nocardiosis with multiple forms of manifestation; nonetheless, disseminated nocardiosis rarely involves the skin and subcutaneous tissues, and this occurs as a result of metastatic spread. Our cases were disseminated nocardiosis in which the metastatic cutaneous involvement, even if rare, provided a clue for the diagnosis. CONCLUSIONS: The pathomorphosis of disseminated nocardiosis may have changed in the current years with more rapid spread due to advanced immunosuppression. For this reason, after clinical suspicion, the prompt start of an active targeted therapy based on rapid microbiological identification might potentially open the way to hopeful results, even in the most immune-compromised patients.

Endo-Aortic vs. Trans-Thoracic Clamping in Right Mini-Thoracotomy Mitral Valve Surgery: Outcome on Myocardial Protection.

Background: Perfusion strategies and aortic clamping techniques for right mini-thoracotomy mitral valve (MV) surgery have evolved over time and remarkable short- and long-term results have been reported. However, some concerns have raised about the adequacy of myocardial protection during the minimally invasive approach, particularly with the endo-aortic clamp (EAC). Aim of this study was to compare the efficacy, in terms of myocardial preservation, of the EAC with the trans-thoracic aortic clamp (TTC) in patients undergoing right mini-thoracotomy MV surgery. Methods: A single center, prospective observational study was performed on patients undergoing right mini-thoracotomy MV surgery with retrograde arterial perfusion and EAC or TTC. A propensity matched analysis was performed to compare the two groups. Primary outcome was the comparison between cardiac troponin T levels measured at different time-points after surgery. Results: Eighty EAC patients were compared with 37 TTC patients. No cases of myocardial infarction or low cardiac-output syndrome were overall reported. No differences were recorded in terms of stroke, peri-operative mortality, and in the release of myocardial markers, lactates levels and need for inotropic support at different time-points after surgery. CK-MB peak levels were significantly lower in the EAC group. Conclusion: Despite concerns arising about the EAC, this prospective study shows equivalence in terms of myocardial preservation of the EAC compared with the TTC in patients undergoing right mini-thoracotomy MV surgery.

HLA-DRB1 mismatch-based identification of donor-derived cell free DNA (dd-cfDNA) as a marker of rejection in heart transplant recipients: A single-institution pilot study.

BACKGROUND: Donor-derived cell-free DNA (dd-cfDNA) is considered a reliable marker of organ damage with potential applications in the follow-up of transplant recipients. METHODS: In this work we present an assay based on the donor-recipient HLA-mismatch (human leukocyte antigen) at the HLA-DRB1 locus to monitor rejection by quantifying the percentage of dd-cfDNA using a droplet digital PCR (polymerase chain reaction) technique. A panel of probes targeting the HLA-DRB1 locus and covering >85% genetic variability was validated and used to assess dd-cfDNA levels in a prospective cohort of 19 adult heart transplant recipients (mean age 50.9±14.8 years). The assay was carried out on a total of 232 liquid biopsies collected at the same time as endomyocardial biopsy (EMB) during routine post-transplant follow-up. RESULTS: Results show a significant increase of dd-cfDNA related to ischemia-reperfusion injury (2.22±2.09%) and to acute cellular rejection (1.71±3.10%) compared to stable conditions (0.43±1.04%, p < 0.0001). On the contrary, no increase was observed during infections or vascular complications, underlining the potential role of this biomarker for rejection monitoring. With a cut-off of 0.11%, the test showed 70.8% specificity (95% CI, 58.17% - 81.40%) and 64.2% sensitivity (95% CI, 49.80% - 76.86%) in discriminating acute rejection from no rejection. CONCLUSIONS: These data demonstrate that this HLA mismatch-based droplet digital PCR method is effective for monitoring rejection in heart transplant recipients. Compared to next generation sequencing approaches, it is far more flexible, less expensive and provides faster results.

Right mini-thoracotomy approach for grown-up congenital heart disease.

BACKGROUND: Right mini-thoracotomy cardiac surgery has been recognized as a safe and effective procedure, with remarkable early and long-terms outcomes. However, most of the literature is focused on mitral valve surgery and few studies report on the minimally invasive approach applied to congenital disease. Aim of this study was to review our experience on patients with grown-up congenital heart (GUCH) undergoing right mini-thoracotomy cardiac surgery. METHODS: Data of patients with GUCH undergoing right mini-thoracotomy cardiac surgery from 2006 to 2019 were retrospectively analyzed. Inclusion criteria were atrial septal defect, partial anomalous pulmonary venous return, partial atrioventricular septal defect, and mitral or tricuspid valve dysfunction in congenital heart diseases. RESULTS: During the study period 127 patients with GUCH underwent right mini-thoracotomy cardiac surgery. Mean age was 43.6 years and more than 60% were females; diagnosis was atrial septal defect in 57 cases (44.9%); 24 patients were redo (18.9%). No cases of stroke and major vascular complications were reported. Conversion to sternotomy was required in one case (0.8%). No residual shunts or valves dysfunction were recorded at the postoperative echocardiographic evaluation. Perioperative mortality was 1.6%. CONCLUSIONS: Right mini-thoracotomy cardiac surgery in selected patients with GUCH allows to avoid the big scar of the sternotomy approach and to accelerate the recovery in a young population. Moreover, in redo cases, it allows the surgeon to reach the heart and the aorta avoiding the well-known risks of a re-sternotomy procedure.

Percutaneous vs. surgical revascularization for patients with unprotected left main stenosis: a meta-analysis of 5-year follow-up randomized controlled trials.

AIMS: A 5-year survival of patients with unprotected left main (ULM) stenosis according to the choice of revascularization (percutaneous vs. surgical) remains to be defined. METHODS AND RESULTS: Randomized controlled trials (RCTs) comparing percutaneous coronary intervention (PCI) vs. coronary artery bypass graft (CABG) with a follow-up of at least 5 years were included. All-cause death was the primary endpoint. MACCE [a composite endpoint of all-cause mortality, myocardial infarction (MI), stroke, and repeat revascularization] along with its single components and cardiovascular (CV) death were the secondary ones. Analyses were stratified according to the use of first- vs. last-generation coronary stents. Subgroup comparisons were performed according to SYNTAX score (below or above 33) and to age (using cut-offs of each trial's subgroup analysis). Four RCTs with 4394 patients were identified: 2197 were treated with CABG, 657 with first generation, and 1540 with last-generation stents. At 5-year rates of all-cause death did not differ [odds ratio (OR) 0.93, 95% confidence interval (CI) 0.71-1.21], as those of CV death and stroke. Coronary artery bypass graft reduced rates of MACCE (OR 0.69, 95% CI 0.60-0.79), mainly driven by MI (OR 0.48, 95% CI 0.36-0.65) and revascularization (OR 0.53, 95% CI 0.45-0.64). Benefit of CABG for MACCE was consistent, although with different extent, across values of SYNTAX score (OR 0.76, 95% CI 0.59-0.97 for values < 32 and OR 0.63, 95% CI 0.47-0.84 for values ≥ 33) while was not evident for 'younger' patients (OR 0.83, 95% CI 0.65-1.07 vs. OR 0.65, 95% CI 0.51-0.84 for 'older' patients). CONCLUSION: For patients with ULM disease followed-up for 5 years, no significant difference was observed in all-cause and cardiovascular death between PCI and CABG. Coronary artery bypass graft reduced risk of MI, revascularization, and MACCE especially in older patients and in those with complex coronary disease and a high SYNTAX score.

Fractional flow reserve guided versus angiographic guided surgical revascularization: A meta-analysis.

BACKGROUND: Clinical benefits of FFR (Fraction Flow Reserve) driven CABG (Coronary Artery Bypass Graft) remain to be established. METHODS: All randomized controlled trials (RCTs) and observational studies with multivariable adjustement were included. MACE (Major Adverse Cardiac Events) was the primary end point, while its single components (death, myocardial infarction, and total vessel revascularization [TVR]) along with number of anastomoses, on pump procedures and graft occlusion at angiographic follow-up were the secondary ones. Each analysis was stratified for RCTs versus observational studies. RESULTS: Four studies (two RCTs and two observational) were included, enrolling 983 patients, 542 angio-guided and 441 FFR-guided. Mean age was 68.45 years, 79% male, with a mean EuroSCORE I of 2.7. Coronary lesions were located in 37% of patients in the left anterior descending artery, 32% in the circumflex artery, and 26% in the right coronary artery. After a mean follow-up of 40 months, risk of MACE did not differ (OR 0.86 [0.63-1.18]) as that of all cause death (OR 0.86 [0.59-1.25]), MI (OR 0.57 [0.30-1.11]) and TVR (OR 1.10 [0.65-1.85]). FFR-driven CABG reduced on-pump procedures (OR 0.58 [0.35-0.93]) and number of anastomoses (-0.40 [-0.80: -0.01]) while incidence of graft occlusion at follow-up did not differ (OR 0.59 [0.30-1.15], all CI 95%). CONCLUSION: Fraction flow reserve driven CABG reduced the number of anastomoses and of on-pump procedures without increasing risk of MACE and without reducing graft occlusion at angiographic follow-up. ID CRD42020211945.

Cellular and humoral cytomegalovirus immunity changes in one-year combined prophylaxis after lung transplantation: suggestions from and for clinical practice.

BACKGROUND: Immune responses, both cellular and humoral, against cytomegalovirus (CMV) are used to predict CMV manifestations in solid organ recipients. The aim of this study is to evaluate CMV enzyme-linked immunospot (ELISPOT) assay and serology during CMV infections, their concordance and variations after lung transplantation (LTx). METHODS: We retrospectively analysed in one year the follow-up data of 43 patients receiving combined CMV prophylaxis with antiviral agents and CMV-specific immunoglobulin G (IgG). CMV infections were investigated by using molecular analyses on both 167 bronchoalveolar lavage and biopsy specimens and 1134 blood samples. Cellular CMV immunity was assessed with specific ELISPOT whereas the humoral one was assessed by quantifying specific immunoglobulins. RESULTS: At the first month after LTx the majority of patients were ELISPOT responders (52.3%) and 30.9% were non-responders. ELISPOT responders had a lower incidence of CMV viremia (p = 0.047), whereas neither effects on CMV pulmonary asymptomatic infection nor on acute rejection were observed. Responders had a higher CMV IgG titre (p < 0.0001) in particular at the first month after LTx (p = 0.0001). Concordance among CMV ELISPOT assay and IgG levels was moderate (Cohen's K 0.524), with an agreement of 89.8%. All ELISPOT responders maintained their status and almost all non-responders became responders during follow-up (92.3%); the percentage of IgG seropositive subjects increased from 74.4% at the first month of follow-up to 97.4% after 1 year. CONCLUSIONS: Despite a moderate concordance with serology, ELISPOT response predicted a lower incidence of CMV viremia in LTx patients; no effects were reported on pulmonary clinical manifestations nor on acute rejection. The ELISPOT response as well as serology changed during the follow-up, not only after first CMV contact.The reviews of this paper are available via the supplemental material section.

Impact of imipenem concentration in lung perfusate and tissue biopsy during clinical ex-vivo lung perfusion of high-risk lung donors.

BACKGROUND: Normothermic ex-vivo lung perfusion (EVLP) limits organ donor shortage by potentially using high-risk donor lungs. Microbial burden reduction has been demonstrated after EVLP using antibiotic prophylaxis with imipenem. However, no data have been published on the clinical consequences of the potential residual bacterial burden. METHODS: Imipenem concentration was measured every hour (T0 to T6) in the lung perfusate and at the end of EVLP (Tf) in biopsies. The antimicrobial activity of perfusate at T1 and Tf against E. coli and K. pneumoniae was evaluated. Lungs were distinguished: no bacterial species in recipients and donors (donor-/recipient-); bacterial species isolated from donors and not from recipients (donor+/recipient-); same bacterial species in both recipients and donors (donor+/recipient+). Interleukin 6 (IL-6) and IL-8 concentrations in lung perfusate, clinical pulmonary infection score (CPIS) and primary graft dysfunction (PGD) were evaluated. RESULTS: Imipenem concentration in perfusate decreased over time. T1 and Tf perfusates exhibited bactericidal activity against E. coli and K. pneumoniae. Overall, T1 perfusates yielded higher bactericidal titers (BTs) than Tf. The donor+/recipient+ group (26% of cases) had higher IL-6 and IL-8 in perfusate and higher CPIS. CONCLUSIONS: Recipients with the same bacterial species isolated in their donors had higher risk of pulmonary inflammation and early post-transplant pneumonia. Improvements in antimicrobial strategies during EVLP are warranted to minimize the consequences of donor associated respiratory infection.

Interventricular Septal Rupture in a 62-Year-Old Man With Familial Amyloid Polyneuropathy.

Cardiac involvement in familial amyloid polyneuropathy consists of arrhythmias, conduction disturbances, and heart failure. To our knowledge, heart rupture has never been described in association with this condition. We report the case of a 62-year-old man with a 6-year history of refractory familial amyloid polyneuropathy who underwent liver transplantation. The operation was complicated by severe hypotension because the neuropathy involved the autonomic system. Perioperatively, the patient had a myocardial infarction, and during the next 10 days, a complete interventricular septal rupture developed, resulting in a systemic-to-pulmonary shunt. Coronary angiographic findings were normal. However, the shunt caused unstable hemodynamics, resulting in cardiogenic shock. An attempt to close the rupture percutaneously failed. The patient underwent successful heart transplantation 50 days later. Macroscopic examination of the explanted heart showed thickening of both ventricles, septal rupture, and a gray scar in the interventricular septum around the cavity. Histopathologic examination revealed intramural amyloid angiopathy. Our case shows that heart rupture can occur in patients with familial amyloid polyneuropathy who have no history of obstructive coronary artery disease, perhaps as a result of tissue fragility caused by amyloid angiopathy. Therefore, autonomic disturbances should be regarded with concern and promptly treated in the perioperative period.

Contemporary biochemical analysis of normal pericardial fluid.

OBJECTIVE: Biochemical analysis of pericardial fluid (PF) is commonly performed for the initial assessment of PF, and the results are usually interpreted according to Light's traditional criteria for the differential diagnosis of transudates versus exudates. However, Light's criteria have been formulated for the biochemical analysis of pleural fluid. The aim of the present paper is to evaluate the normal composition of PF in candidates for cardiac surgery. METHODS: Cohort study with analysis of PF from candidates for cardiac surgery. Exclusion criteria were previous pericardial disease or cardiac surgery, prior myocardial infarction within 3 months, systemic disease (eg, systemic inflammatory diseases, uremia) or drug with potentiality to affect the pericardium. RESULTS: Fifty patients (mean age was 67 years; 95% CI 64 to 71, 29 males, 58.0%) were included in the present analysis. Levels of small molecules were similar in blood and PF. Total proteins in PF was, on average, 0.5 times lower than corresponding plasma levels (p=0.041), while the level of pericardial lactate dehydrogenase was, on average, 1.06 times higher than plasma (p=0.55). Moreover, mononuclear cells were more concentrated in PF than plasma (p=0.17). Traditional Light's criteria misclassified all PFs as exudates. CONCLUSIONS: Traditional Light's criteria misclassified normal PFs in candidates for cardiac surgery as exudates. This study suggests their futility for the biochemical analysis of PF in clinical practice.