LIONS PREY: A New Logistic Scoring System for the Prediction of Malignant Pulmonary Nodules

OBJECTIVES

Classifying radiologic pulmonary lesions as malignant is challenging. Scoring systems like the Mayo model lack precision in predicting the probability of malignancy. We developed the logistic scoring system 'LIONS PREY' (Lung lesION Score PREdicts malignancY), which is superior to existing models in its precision in determining the likelihood of malignancy.

METHODS

We evaluated all patients that were presented to our multidisciplinary team between January 2013 and December 2020. Availability of pathological results after resection or CT-/EBUS-guided sampling was mandatory for study inclusion. Two groups were formed: Group A (malignant nodule; n = 238) and Group B (benign nodule; n = 148). Initially, 22 potential score parameters were derived from the patients' medical histories.

RESULTS

After uni- and multivariate analysis, we identified the following eight parameters that were integrated into a scoring system: (1) age (Group A: 64.5 ± 10.2 years vs. Group B: 61.6 ± 13.8 years; multivariate p-value: 0.054); (2) nodule size (21.8 ± 7.5 mm vs. 18.3 ± 7.9 mm; p = 0.051); (3) spiculation (73.1% vs. 41.9%; p = 0.024); (4) solidity (84.9% vs. 62.8%; p = 0.004); (5) size dynamics (6.4 ± 7.7 mm/3 months vs. 0.2 ± 0.9 mm/3 months; p < 0.0001); (6) smoking history (92.0% vs. 43.9%; p < 0.0001); (7) pack years (35.1 ± 19.1 vs. 21.3 ± 18.8; p = 0.079); and (8) cancer history (34.9% vs. 24.3%; p = 0.052). Our model demonstrated superior precision to that of the Mayo score (p = 0.013) with an overall correct classification of 96.0%, a calibration (observed/expected-ratio) of 1.1, and a discrimination (ROC analysis) of AUC (95% CI) 0.94 (0.92-0.97).

CONCLUSIONS

Focusing on essential parameters, LIONS PREY can be easily and reproducibly applied based on computed tomography (CT) scans. Multidisciplinary team members could use it to facilitate decision making. Patients may find it easier to consent to surgery knowing the likelihood of pulmonary malignancy. The LIONS PREY app is available for free on Android and iOS devices.

TTF-1 status in early-stage lung adenocarcinoma is an independent predictor of relapse and survival superior to tumor grading

OBJECTIVES

Thyroid transcription factor 1 (TTF-1) is a well-established independent prognostic factor in lung adenocarcinoma (LUAD), irrespective of stage. This study aims to determine if TTF-1's prognostic impact is solely based on histomorphological differentiation (tumor grading) or if it independently relates to a biologically more aggressive phenotype. We analyzed a large bi-centric LUAD cohort to accurately assess TTF-1's prognostic value in relation to tumor grade.

PATIENTS AND METHODS

We studied 447 patients with resected LUAD from major German lung cancer centers (Berlin and Cologne), correlating TTF-1 status and grading with clinical, pathologic, and molecular data, alongside patient outcomes. TTF-1's impact was evaluated through univariate and multivariate Cox regression. Causal graph analysis was used to identify and account for potential confounders, improving the statistical estimation of TTF-1's predictive power for clinical outcomes.

RESULTS

Univariate analysis revealed TTF-1 positivity associated with significantly longer disease-free survival (DFS) (median log HR -0.83; p = 0.018). Higher tumor grade showed a non-significant association with shorter DFS (median log HR 0.30; p = 0,62 for G1 to G2 and 0.68; p = 0,34 for G2 to G3). In multivariate analysis, TTF-1 positivity resulted in a significantly longer DFS (median log HR -0.65; p = 0.05) independent of all other parameters, including grading. Adjusting for potential confounders as indicated by the causal graph confirmed the superiority of TTF-1 over tumor grading in prognostics power.

CONCLUSIONS

TTF-1 status predicts relapse and survival in LUAD independently of tumor grading. The prognostic power of tumor grading is limited to TTF-1-positive patients, and the effect size of TTF-1 surpasses that of tumor grading. We recommend including TTF1 status as a prognostic factor in the diagnostic guidelines of LUAD.

The impact of thymectomy in subgroups of Myasthenia gravis patients: a single center longitudinal observation

BACKGROUND

Myasthenia gravis (MG) is a rare neuromuscular disorder. Symptoms can range from ptosis only to life threatening myasthenic crisis. Thymectomy is recommended for anti-acetylcholine receptor-antibody positive patients with early-onset MG. Here, we investigated prognostic factors shaping therapeutic outcomes of thymectomy to improve patient stratification.

METHODS

We retrospectively collected single-center data from a specialized center for MG from all consecutive adult patients that underwent thymectomy from 01/2012 to 12/2020. We selected patients with thymoma-associated and non-thymomatous MG for further investigations. We analyzed the patient collective regarding perioperative parameters in relation to the surgical approach. Furthermore, we investigated the dynamics of the anti-acetylcholine receptor-antibody titers and concurrent immunosuppressive therapies, as well as the therapeutic outcomes in dependence of clinical classifications.

RESULTS

Of 137 patients 94 were included for further analysis. We used a minimally invasive approach in 73 patients, whereas 21 patients underwent sternotomy. A total of 45 patients were classified as early-onset MG (EOMG), 28 as late-onset MG (LOMG) and 21 as thymoma-associated MG (TAMG). The groups differed in terms of age at diagnosis (EOMG: 31.1 ± 12.2 years; LOMG: 59.8 ± 13.7 years; TAMG: 58.6 ± 16.7 years; p < 0.001). Patients with EOMG and TAMG were more often female than patients in the LOMG group (EOMG: 75.6%; LOMG: 42.9%; TAMG: 61.9%; p = 0.018). There were no significant differences in outcome scores (quantitative MG; MG activities of daily living; MG Quality of Live) with a median follow-up of 46 months. However, Complete Stable Remission was achieved significantly more frequently in the EOMG group than in the other two groups (p = 0.031). At the same time, symptoms seem to improve similarly in all three groups (p = 0.25).

CONCLUSION

Our study confirms the benefit of thymectomy in the therapy of MG. Both, the concentration of acetylcholine receptor antibodies and the necessary dosage of cortisone therapy show a continuous regression after thymectomy in the overall cohort. Beyond EOMG, groups of LOMG and thymomatous MG responded to thymectomy as well, but therapy success was less pronounced and delayed compared to the EOMG subgroup. Thymectomy is a mainstay of MG therapy to be considered in all subgroups of MG patients investigated.

Hemangiosis carcinomatosa as an independent risk factor for long-term survival in Non-Small Cell Lung Cancer patients

OBJECTIVES

Recent studies have shown that blood vessel invasion (V1) influences the long-term survival of patients with Non-Small Cell Lung Cancer (NSCLC). The aim of the present study was to emphasize V1 as an independent risk factor. We evaluated the effects of V1 on the survival of NSCLC patients with UICC stages I, II, and III after surgery.

METHODS

This retrospective study includes 747 consecutive patients with NSCLC who underwent anatomic resection and radical lymphadenectomy at our institution between January 2012 and December 2020. V1- were compared to V0-patients (no blood vessel invasion). All patients received adjuvant therapy according to European guidelines when indicated. After excluding patients with detection of lymphangiosis carcinomatosa, tumor-cells at the resection margin, distant metastases and those, that received neoadjuvant therapy, 1-, 3- and 5- year survival rates were assessed by Kaplan-Meier method. To proof V1 as an independent risk factor, a propensity score matched (PSM) analysis was performed regarding age, gender, UICC-stage, lymph-node involvement, and comorbidities.

RESULTS

A total of 461 patients (V0: 440; V1: 21) were included in this analysis. Baseline characteristics did not show any significant difference. Mean age in V0-group was 65.7 ± 10.5 years and 64.1 ± 8.6 years in V1-group (p-value = 0.5). In the V0-group 54.8% were male, whereas in the V1-group this number was 66.7% (p-value = 0.37). Mean survival in V1-group was significantly shorter compared to V0-group (V1: 45.8 ± 9.3 months; V0: 81.1 ± 1.1 months; p-value<0.001). This was confirmed after applying a propensity score matched analysis (V0: 99.9 ± 4.9 months; V1: 45.8 ± 9.3 months; p-value<0.001) - V1 is a prognostic marker independent of UICC stage. The 1-, 3- and 5-year survival rates were significantly shorter for V1-patients (1-year: V0: 100%; V1: 70.6%; p-value = 0.012) (3-year: V0: 95.2%; V1: 46.2%; p-value = 0.002) (5-year: V0: 90.5%; V1: 36.4%; p-value = 0.003).

CONCLUSION

As we have shown with our investigations, V1 has a major impact on long-term survival in NSCLC patients and furthermore, acts as an independent risk factor. Due to our small but specified sample size, our statement should be confirmed by a multicenter study. In the meantime, we suggest making the implementation of the V0/V1 specification mandatory in the tumor classification.

Cancer-specific immune evasion and substantial heterogeneity within cancer types provide evidence for personalized immunotherapy

The immune response against cancer is orchestrated by various parameters and site-dependent specificities have been poorly investigated. In our analyses of ten different cancer types, we describe elevated infiltration by regulatory T cells as the most common feature, while other lymphocyte subsets and also expression of immune-regulatory molecules on tumor-infiltrating lymphocytes showed site-specific variation. Multiparametric analyses of these data identified similarities of renal and liver or lung with head and neck cancer. Co-expression of immune-inhibitory ligands on tumor cells was most frequent in colorectal, lung and ovarian cancer. Genes related to antigen presentation were frequently dysregulated in liver and lung cancer. Expression of co-inhibitory molecules on tumor-infiltrating T cells accumulated in advanced stages while T-cell abundance was related to enhanced expression of genes related to antigen presentation. Our results promote evaluation of cancer-specific or even personalized immunotherapeutic combinations to overcome primary or secondary resistance as major limitation of immune-checkpoint inhibition.

High sensitivity of PD-L1 analysis from pleural effusion in nonsmall cell lung cancer

Background: Programmed cell death protein 1 (PD-1)/programmed cell death protein ligand 1 (PD-L1) immune checkpoint inhibitors have been approved for monotherapy of metastatic nonsmall cell lung cancer (mNSCLC) depending on tumour cells' PD-L1 expression. Pleural effusion is common in mNSCLC. The significance of immunocytochemistry PD-L1 analysis from pleural effusion samples is unclear. Aim: The aim of the study was to analyse the sensitivity regarding immunocytochemistry PD-L1 analysis of pleural effusion in NSCLC as compared to immunohistochemistry of pleural biopsies. Patients and Methods: Fifty consecutive subjects (17 female, median age 72.5 years, seven never-smokers) were enrolled in this prospective controlled two-centre study. Inclusion criteria were pleural effusion, suspected or known lung cancer, indication for pleural puncture and thoracoscopy, and written informed consent. Immunocytochemistry and immunohistochemistry PD-L1 analyses were performed with the Dako-PDL1-IHC-22C3pharmDx assay. Analysis for sensitivity, specificity, and positive and negative predictive value was performed for PD-L1 detection from pleural effusion. Results: 50 subjects underwent pleural puncture and thoracoscopy. Pathological diagnoses were lung cancer (48), lymphoma (1) and mesothelioma (1). Sensitivity, specificity, positive predictive value and negative predictive value of PD-L1-testing with expression ≥50% defined as positive were 100% (95% CI 46-100%), 63% (36-84%), 45% (18-75%) and 100% (66-100%), and with expression ≥1% defined as positive 86% (56-97%), 43% (12-80%), 75% (47-92%) and 60% (17-93%). Conclusion: PD-L1 analysis in tumour-positive pleural effusion samples shows a very high sensitivity and negative predictive value, especially regarding PD-L1 expression levels ≥50% (European Medicines Agency approval). Negative results are reliable and help in the decision against a first-line checkpoint inhibitor monotherapy. However, a 1% cut-off level (United States Food and Drug Administration approval) leads to a markedly lower negative predictive value, making other invasive procedures necessary (NCT02855281).

Detection of circulating tumor DNA by digital droplet PCR in resectable lung cancer as a predictive tool for recurrence

Lung cancer is the leading cause of cancer-related mortality worldwide due to difficulties in early detection and high postsurgical recurrence rate. Current European Guidelines recommend follow-up via computerized tomography (CT) scans on regular basis within the first 2 years after radical surgical resection. Despite these efforts, recurrence rates remain high with 30-70 %. Therefore, it is imperative to develop predictive markers for metastases and postsurgical recurrence using minimally invasive methods. This prospective study aims at defining the feasibility of detecting circulating tumor DNA (ctDNA) in presurgical plasma samples of patients with lung cancer by digital droplet PCR. Resected tumor tissue and simultaneous blood samples were collected from 24 patients with lung cancer in stage I-IIIA (12 stage I, 8 stage II, 4 stage III). Genomic DNA from the tumor tissue samples were analyzed for hotspot mutations using a 17 gene panel next-generation sequencing (NGS) assay. CtDNA from corresponding plasma samples were analyzed using digital droplet PCR (ddPCR). Additionally, DNA sequencing results were correlated with patients' outcome. At least one somatic mutation was detected by NGS (96 %) in 23 of the tested tissue samples. DdPCR detected mutations in circulating cell-free DNA (ccfDNA) of nine patients' samples (9/23, 39 %). Postsurgical outcome analysis was performed for those patients who had received complete tumor resection (n = 21). Four of them suffered from an early relapse within the first two years after surgery, including two with detectable somatic mutations in ccfDNA during primary staging. Taken together, we showed that the 17 gene panel assay revealed in 23 of 24 patients at least one somatic mutation in the primary tumor by NGS. Tumor-specific mutation was detectable in 39 % from the blood of early stage lung cancer patients by ddPCR.

[Chest wall replacement]

The optimal surgical reconstruction of chest wall defects especially in the context of posttraumatic, oncological and congenital etiologies has a large impact on the recovery of the patients. Regardless of the etiology, various complications, such as a generally impaired respiratory physiology in an unstable thorax or decreased pulmonary clearance associated with acute and chronic pulmonary infections, may impair the recovery of affected patients. The postoperative occurrence of an intrathoracic dead space may lead to a difficult to treat empyema. Each thoracic wall defect must be accurately assessed and treated according to size, depth and location on the chest. The complexity of this condition and the resulting complications require the highest degree of surgical care which should be interdisciplinary both preoperatively and postoperatively.

Transbronchial cryobiopsy in fibrosing interstitial lung disease: modifications of the procedure lead to risk reduction

Sixty-one subjects with fibrosing interstitial lung disease were prospectively analysed to determine the efficacy of transbronchial cryobiopsy (CryoTBB) and the effect of procedural modifications which were introduced after an interim analysis of the first 19 subjects. The modifications significantly reduced complication rates from 84% to 14% (p<0.001). 30-day-mortality was 2%. The algorithm with initial CryoTBB and surgical lung biopsy (SLB) as optional step-up procedure was feasible. CryoTBB led to a confident diagnosis in 46/61 subjects (75%). Only 21% out of all subjects were forwarded for SLB. As the modified CryoTBB reduced but not eliminated the risk of severe complications, tissue sampling should be limited to patients where confident diagnosis enables life prolonging therapy. Trial registration number: NCT01714518.

[Lung Metastasectomy in Pulmonary Metastatic Colorectal Carcinoma]

BACKGROUND

Patients with colorectal cancer are often affected by liver and lung metastases. Besides systemic therapies, lung metastasectomy is a suitable treatment option after complete resection of primary colorectal carcinoma and even concomitant liver metastases.

MATERIAL AND METHODS

We have performed a systematical literature research of all studies published after 01. 01. 2010. Studies reporting on at least 100 patients undergoing lung metastasectomy after 01. 01. 2000 have been included in our final analysis. Operative data, survival data and prognostic factors have been extracted.

RESULTS

Eleven study cohorts reporting on 2,891 patients could be included in the final analysis. Complete resection could be achieved in most cases and thoracic surgeons preferred subsegmental resections. Pathological examination revealed thoracic lymph node involvement in 2.3 to 18.2% of patients. The postoperative mortality varied from 0 to 0.5%. The median follow up ranged between 27.5 and 65.1 months. Pulmonary metastasectomy resulted in 5-year survival rates of 53 to 75.5% and 5-year progression-free survival rates of 33 to 50.9%. Intrathoracic recurrence occurred in 25.2 to 42.9% of patients with complete resection and five-year survival rates ranged from 49 to 75.5% after repeat pulmonary metastasectomy. Analysis of prognostic factors revealed that number, size and distribution of lung metastases are minor important prognostic factors. Moreover, current data suggest disadvantageous post-metastasectomy survival for patients with elevated pre-metastasectomy serum CEA level or intrathoracic lymph node metastases in comparison with the control groups. Nevertheless, even in these patients, lung metastasectomy might be a beneficial procedure.

CONCLUSIONS

In patients with colorectal cancer and resectable isolated lung or combined liver and lung metastases pulmonary resection should be the treatment of choice. Pulmonary metastasectomy should be combined with thoracic lymph node resection to remove potential lymph node metastases. Repeat metastasectomy should be offered to patients suffering from isolated intrathoracic recurrence.

Lung Metastasectomy for Pulmonary Metastatic Breast Carcinoma

Breast carcinoma with pulmonary metastasis can be treated locally or systemically. Following primary tumour resection patients with isolated, completely resectable pulmonary nodules and definite functional operability can be offered lung metastasis resection. Following metastasectomy a median survival of 32 to 96.6 months can be achieved with corresponding five-year survival rates between 30.8 and 54.4%. The procedure is associated with a mortality rate of 0 to 3%. The most important independent prognostic factor for long-term survival is complete resection of all lung lesions. The configuration and pattern of metastasis as well as disease-free interval, hormone and HER2/neu receptor status also appear to influence prognosis, but are of lesser importance. Intrapulmonary recurrence of metastases may, after careful selection on a case-by-case basis, also be treated operatively. In some cases this is associated with a favourable long-term prognosis. Pulmonary metastasectomy should be the treatment of choice for selected patients with metastatic breast carcinoma.

[Surgery for Pulmonary Metastases in Patients with Advanced Soft Tissue and Osteosarcomas]

Background Advanced soft tissue or osteosarcoma is often associated with lung metastases. Curative pulmonary metastasectomy is appropriate for patients with successfully resected primary cancer who show no evidence of extrapulmonary metastases, with proven functional operability and completely resectable metastases. Material and Methods Systematic literature research and qualitative analysis of studies on patients undergoing lung metastasectomy after resection of primary sarcoma published since 01.01.2010. We assessed operative findings, survival data and prognostic factors. Results Pulmonary metastasectomy results in a median postmetastasectomy survival of 8.76 to 69.9 months. Five year survival rates after metastasectomy vary between 21.7 and 56.8%. The patients' prognosis depends particularly on complete resection of all suspected metastases. Intrapulmonary recurrence could be treated by repeated resection, but this procedure requires careful decision for indication. Re-metastasectomy might result in a favourable outcome in selected cases. Conclusion Pulmonary metastasectomy should be considered as treatment of choice in selected patients with isolated lung metastases from osteosarcoma. Optimal indication might lead to an advantage in patients with metastasectomy of isolated lung metastases from soft tissue.

Is manual palpation of the lung necessary in patients undergoing pulmonary metastasectomy?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was whether manual palpation of the lung is necessary in patients undergoing pulmonary metastasectomy. In total, 56 articles were found using the described search strategy. After screening these articles and their references, 18 publications represented the best evidence to answer the clinical question. No randomized controlled trial addressing the three-part question was available. The authors, journal, date and country of publication, patient group, study type, relevant outcomes and results of these papers were tabulated. The studies reported on 1472 patients with different primary cancers. The patients underwent more than 1630 pulmonary metastasectomies between 1990 and 2014 after the treatment of primary cancer. Almost three quarters of patients underwent open procedures like thoracotomy or sternotomy. Most frequently, helical CT with a slice thickness ranging between 1 and 10 mm was used for preoperative imaging. The sensitivity in detecting pulmonary nodules ranged from 34 to 97%. The corresponding sensitivity rates for PET-CT were 66-67.5 and 75% for high-resolution CT. The positive predictive value for lesions detected by helical CT varied from 47 to 96%. Helical CT reached a specificity between 54 and 93% in detecting pulmonary nodules. The surgeons identified more nodules by meticulous palpation than helical CT. It is noteworthy that up to 48.5% of these palpated nodules were benign lesions (false-positive). Patients with smaller imaged nodules, multiple imaged nodules or primary mesenchymal tumour are more likely to have occult pulmonary nodules. We conclude that not all palpable pulmonary nodules can be imaged preoperatively. Thoracotomy allows the manual palpation of the ipsilateral hemithorax and might be superior to video-assisted thoracic surgery regarding radical resection. However, not all palpable nodules are malignant, and the impact of non-resected pulmonary metastases on patient survival is not clearly evaluated.

[Surgical therapy of lung metastases from head and neck cancer]

Pulmonary metastasectomy is an established procedure in oncological therapeutic concepts. A systematic literature search and an analysis of all studies published since 01.01.2000 should evaluate the advantage of pulmonary metastasectomy for patients with primary head and neck cancer. Lung metastases develop in 1.9-13% of head and neck cancer patients. Following metastasectomy, patients reach a median survival of 9.5-78 months and 5-year survival rates of up to 58% are achieved. Intrathoracic recurrence occurs in 18.4-81.8% of patients, selected instances of which can be successfully treated by remetastasectomy. Patients with squamous cell carcinoma have the worst prognosis, but could also become long-term survivors (≥ 60 months). Pulmonary metastasectomy is frequently the only potentially curative therapeutic approach and offers a better long-term survival than nonsurgical therapies. Lung metastasectomy is thus the treatment of choice in selected patients with pulmonary metastases from primary head and neck cancer.

Prediction of mortality in intensive care unit cardiac surgical patients

OBJECTIVES

The purpose of this study was to develop a specific postoperative score in intensive care unit (ICU) cardiac surgical patients for the assessment of organ dysfunction and survival. To prove the reliability of the new scoring system, we compared its performance to existing ICU scores.

METHODS

This prospective study consisted of all consecutive adult patients admitted after cardiac surgery to our ICU over a period of 5.5 years. Variables were evaluated using the patients of the first year who stayed in ICU for at least 24h. The reproducibility was then tested in two validation sets using all patients. Performance was assessed with the Hosmer-Lemeshow (HL) goodness-of-fit test and receiver operating characteristic (ROC) curves and compared with the Acute Physiology and Chronic Health Evaluation (APACHE II) and Multiple Organ Dysfunction Score (MODS). The outcome measure was defined as 30-day mortality.

RESULTS

A total of 6007 patients were admitted to the ICU after cardiac surgery. Mean HL values for the new score were 5.8 (APACHE II, 11.3; MODS, 9.7) for the construction set, 7.2 (APACHE II, 8.0; MODS, 4.5) for the validation set I and 4.9 for the validation set II. The mean area under the ROC curve was 0.91 (APACHE II, 0.86; MODS, 0.84) for the new score in the construction set, 0.88 (APACHE II, 0.84; MODS, 0.84) in the validation set I and 0.92 in the validation set II.

CONCLUSIONS

Most of general ICU scoring systems use extensive data collection and focus on the first day of ICU stay. Despite this fact, general scores do not perform well in the prediction of outcome in cardiac surgical patients. Our new 10-variable risk index performs very well, with calibration and discrimination very high, better than general severity systems, and it is an appropriate tool for daily risk stratification in ICU cardiac surgery patients. Thus, it may serve as an expert system for diagnosing organ failure and predicting mortality in ICU cardiac surgical patients.

Third-generation mobile phones (UMTS) do not interfere with permanent implanted pacemakers

AIMS

Third-generation mobile phones, UMTS (Universal Mobile Telecommunication System), were recently introduced in Europe. The safety of these devices with regard to their interference with implanted pacemakers is as yet unknown and is the point of interest in this study.

METHODS AND RESULTS

The study comprised 100 patients with permanent pacemaker implantation between November 2004 and June 2005. Two UMTS cellular phones (T-Mobile, Vodafone) were tested in the standby, dialing, and operating mode with 23 single-chamber and 77 dual-chamber pacemakers. Continuous surface electrocardiograms (ECGs), intracardiac electrograms, and marker channels were recorded when calls were made by a stationary phone to cellular phone. All pacemakers were tested under a "worst-case scenario," which includes a programming of the pacemaker to unipolar sensing and pacing modes and inducing of a maximum sensitivity setting during continuous pacing of the patient. Patients had pacemaker implantation between June 1990 and April 2005. The mean age was 68.4 +/- 15.1 years. Regardless of atrial and ventricular sensitivity settings, both UMTS mobile phones (Nokia 6650 and Motorola A835) did not show any interference with all tested pacemakers. In addition, both cellular phones did not interfere with the marker channels and the intracardiac ECGs of the pacemakers.

CONCLUSION

Third-generation mobile phones are safe for patients with permanent pacemakers. This is due to the high-frequency band for this system (1,800-2,200 MHz) and the low power output between 0.01 W and 0.25 W.

Gaseous emboli during off-pump surgery with T-graft technique, two different mechanisms

OBJECTIVES

Gaseous embolism is a possible complication during off-pump coronary surgery with the use of a blower and can cause ischemic injuries. We describe two different possible mechanisms of carbon-dioxide embolization.

METHODS

Out of 2196 coronary bypass surgeries, between 1 January 2007 and 31 December 2009, there were 977 off-pump operations. Two off-pump cases (0.2%) had gaseous (carbon-dioxide) emboli that migrated against blood stream proximally through T-anastomoses and then into the native coronary vessels. These emboli caused a temporary haemodynamic deterioration in other territories. Two types of T-anastomoses were included [saphenous vein on left internal thoracic artery (LITA) or right internal thoracic artery (RITA) on LITA].

RESULTS

Simple procedures and measurements were necessary but enough to regain haemodynamic stability. There was no effect on the postoperative outcome.

CONCLUSION

We have concluded that carbon-dioxide emboli can also cause massive but temporary haemodynamic deterioration during off-pump surgery despite higher solubility in blood. The blower should be used only when a bull-dog clamp is applied on the graft. Also, proper de-airing and flushing of grafts is very important and avoids consequences of the trapped small emboli.