EPR spectroscopy solutions for assessment of decellularization of intrathoracic organs and tissues

Using EPR spectroscopy it was established that the determination of the concentration of paramagnetic centers in lyophilized tissues allows indirect evaluation of the quality of decellularization of intrathoracic organs (diaphragm, heart, and lungs), since the content of paramagnetic particles in them can serve as a criterion of cell viability and points to the necessity to repeat decellularization. Experiments in rats showed that the EPR spectra of the native thoracic organs contained paramagnetic centers with g-factor values ranging from 2.007 to 2.011 at a concentration of 10(-8) to 6.62 × 10(-7) mol/g of lyophilized tissue, whereas in all decellularized tissues of the same organs paramagnetic particles were not detected.

EXPERIENCE OF PERFUSION RECELLULARIZATION OF BIOLOGICAL LUNG SCAFFOLD IN RATS

Aim.The main aim of our research is to evaluate the process of rat lung decellularization and recellularization as the initial step of tissue-engineered organs creation.

Materials and methods.Rat lung decellularization was performed by perfusion with detergents and enzymes with concomitant atmospheric air ventilation through the trachea. The quality of decellularization was analyzed with routine histological and immunohistochemical staining techniques, DNA content was determined quantitatively by spectrophotometer. For static and whole organ reseeding as a model of cells’ behavior mesenchymal multipotent stromal cells were used. Recellularization was followed by assessment of the cellular metabolic activity by colorimetric method; cell viability was analyzed by calcein and ethidium homodimer staining. Matrix qualitative evaluation after recellularization was performed using immunohistochemical staining methods.

Results.92% of allogeneic DNA was eliminated after decellularization. Histological staining revealed no residual cells and cell nuclei; preservation of the fibers of extracellular matrix was confirmed by immunohistochemical staining for laminin, elastin, fibronectin, collagen types I and IV before and after decellularization. The scaffold does not exhibit toxic properties after reseeding; cell viability and metabolic activity were proved after cultivation.

Conclusion.The experience of rat lung decellularization and recellularization can be the prospective basis for protocols of organ recellularization and tissue engineered lungs creation.

Laryngeal transplantation in minipigs: early immunological outcomes

Despite recent tissue-engineering advances, there is no effective way of replacing all the functions of the larynx in those requiring laryngectomy. A recent clinical transplant was a success. Using quantitative immunofluorescence targeted at immunologically relevant molecules, we have studied the early (48 h and 1 week) immunological responses within larynxes transplantated between seven pairs of National Institutes of Health (NIH) minipigs fully homozygous at the major histocompatibility complex (MHC) locus. There were only small changes in expression of some molecules (relative to interindividual variation) and these were clearest in samples from the subglottic region, where the areas of co-expression of CD25(+) CD45RC(-) CD8(-) and of CD163(+) CD172(+) MHC-II(-) increased at 1 week after transplant. In one case, infiltration by recipient T cells was analysed by T cell receptor (TCR) Vβ spectratype analysis; this suggested that changes in the T cell repertoire occur in the donor subglottis mucosal tissues from day 0 to day 7, but that the donor and recipient mucosal Vβ repertoires remain distinct. The observed lack of strong immunological responses to the trauma of surgery and ischaemia provides encouraging evidence to support clinical trials of laryngeal transplantation, and a basis on which to interpret future studies involving mismatches.

Laryngeal transplantation in minipigs: vascular, myologic and functional outcomes

There is no effective way of replacing all the functions of the larynx in those requiring laryngectomy. Regenerative medicine offers promise, but cannot presently deliver implants with functioning neuromuscular units. A single well-documented laryngeal transplant in man was a qualified success, but more information is required before clinical trials may be proposed. We studied the early response of the larynx to laryngeal transplantation between 17 pairs of NIH minipigs full matched at the MHC2 locus. Following iterative technical improvements, pigs had good swallowing and a patent airway at 1 week. No significant changes in mucosal blood flux were observed compared with pre-operative measurements. Changes in muscle morphology and fibre phenotype were observed in transplant muscles retrieved after 7 days: the levels of fast and slow myosin heavy chain (MyHC) protein were reduced and embryonic MyHC was up regulated consistent with denervation induced atrophy. At 1 week laryngeal transplantation can result in good swallowing, and is not associated with clinical evidence of ischemia-reperfusion injury in MHC-matched pigs.

Artificial lung: current perspectives

While the number of the patients suffering from end-stage pulmonary disease has been increasing, the most common treatment for this entity remains mechanical ventilation that entails the risks of lung damage by itself. Although the lung protective strategy for the prevention of further damage to the lung tissue has been elucidated and performed, mechanical ventilation alone as the management tactic coping with the patients of acute respiratory distress syndrome, chronic respiratory failure and lung transplantations has been a frustrated scenario. Extracorporeal membrane oxygenation or extracorporeal lung assist have been applied to these patients with occasional success, but it always accompanies difficulties such as multiple blood transfusion, labor intensity, technically complexity and tendency to infection. In contrast to advances in the development of cardiac or renal support systems for adults, the development of extra-, para- and intracorporeal mechanical systems for acute or chronic lung respiratory failure has logged far behind. It has been mostly due to the lack of the capable technologies. Entering 21st century with advent of new technology especially invention of the low resistance oxygenator, the developments of artificial lungs have entered the new stage. In this report current status of the artificial lungs will be reviewed.

Early immunological changes associated with laryngeal transplantation in a major histocompatibility complex-matched pig model

Laryngeal transplantation is an increasingly viable proposition for patients with irreversible diseases of the larynx. One human transplant has been performed successfully, but many questions remain before routine transplantation can begin. In order to measure the immunological changes in mismatched transplants, it is first necessary to know the immediate combined effects of ischaemia-reperfusion injury (IRI) plus the added insult of major surgery in a fully matched setting. We measured the changes in immunologically active mucosal cells following 3 h of cold ischaemia and 8 h of in situ reperfusion in a major histocompatibility complex (MHC)-matched minipig model (n = 4). Biopsies were prepared for quantitative, multiple-colour immunofluorescence histology. The number of immunologically active cells was significantly altered above (supraglottis) and below (subglottis) the vocal cords following transplantation and reperfusion (P < 0.05, P < 0.001, respectively). However, the direction of the change differed between the two subsites: cell numbers decreased post-transplant in the supraglottis and increased in the subglottis. Despite the statistical evidence for IRI, these changes were less than the large normal inter- and intrapig variation in cell counts. Therefore, the significance of IRI in exacerbating loss of function or rejection of a laryngeal allograft is open to question. Longer-term studies are required.

Generation of a bioartificial fibromuscular tissue with autoregenerative capacities for surgical reconstruction

INTRODUCTION

Anecdotal clinical reports denote first tissue engineering applications entering medical practice. Currently it is still unknown, if these new types of implants will tolerate the specific needs in cancer patients undergoing postoperative chemo- and radiotherapy.

METHODS

We implemented a radiotherapy protocol (cumulative dosis 40 Gy) on generated human bioartificial fibromuscular tissues in vitro. We monitored tissue vitality during radiotherapy and tissue recovery (8 weeks follow up period) applying histological methods.

RESULTS

The biopsy procedure and seeding techniques yielded a viable 3 dimensional bioartificial human tissue. Radiation resulted in immediate devitalization without destroying tissue integrity. The bioartificial tissue recovered entirely in vitro within 6 weeks.

CONCLUSION

Bioartificial human implants appear applicable for surgical reconstruction in oncologic patients potentially facing postoperative radiotherapy.

Model for experimental revascularized laryngeal allotransplantation

BACKGROUND

Although a human laryngeal transplant has been undertaken successfully, important questions remain that require a suitable animal model.

METHODS

A pig model for allotransplantation has been developed. Organ perfusion was studied in nine animals before four transplants were performed in congenic (unrecovered) animals and eight in unmatched (recovered) animals. Larynges were regularly examined endoscopically until death at 14 days. Immunosuppression included the use of tacrolimus. Revascularization was achieved by anastomosing the donor right cervical vascular tree to the recipient common carotid. In recovered animals, four allografts were placed orthotopically and four heterotopically.

RESULTS

The pig larynx was perfused adequately via the right cervical vascular tree and congenic grafts were well tolerated. Of eight allografts, seven were well tolerated and remained healthy for the duration of the study (14 days). One allograft became infected between days 4 and 7 after operation. Median operating time was 6 h, with a median cold ischaemia time of 3 h.

CONCLUSION

Revascularized allotransplants of the larynx can be undertaken reliably in pigs and this provides a preclinical model for studies of laryngeal transplantation.

Low molecular weight dextran sulfate prevents complement activation and delays hyperacute rejection in pig-to-human xenotransplantation models

Dextran sulfate of 5000 molecular weight (DXS 5000) is known to block complement activation as well as the intrinsic coagulation cascade by potentiation of C inhibitor. The effect of DXS 5000 on hyperacute rejection (HAR) was tested in pig-to-human xenotransplantation models. For in vitro testing, a cytotoxicity assay was used with the pig kidney cell line PK15 as target cells and fresh, undiluted human serum as antibody and complement source. Ex vivo pig lung perfusion was chosen to assess DXS 5000 in a physiologic model. Pig lungs were perfused with fresh, citrate-anticoagulated whole human blood to which 1 or 2 mg/ml DXS 5000 were added; the lungs were ventilated and the blood de-oxygenated. Pulmonary vascular resistance (PVR) and blood oxygenation (deltapO2) were monitored throughout the experiment. Autologous pig blood and human blood without DXS 5000 served as controls. In the PK 15 assay DXS 5000 led to a complete, dose-dependent inhibition of human serum cytotoxicity with an average IC50 of 43 +/- 18 microg/ml (n=8). Pig lungs perfused with untreated human blood (n=2) underwent HAR within 105 +/- 64 min, characterized by increased PVR, decrease of deltapO2, and generalized edema. Microscopically, capillary bleeding as well as deposition of human antibodies, complement and fibrin could be observed. Addition of DXS 5000 (n=4) prolonged lung survival to 170 +/- 14 min for 1 mg/ml and 250 +/- 42 min for 2 mg/ml. and PVR values as well as edema formation were comparable to control lungs that were perfused with autologous pig blood (n=2). Activation of complement (activation products in serum, deposition on lung tissue) and the coagulation system (fibrin monomers) were significantly diminished as compared to human blood without DXS 5000. Binding of anti-Gal antibodies was not influenced, and in vitro experiments showed no evidence of complement depletion by DXS 5000. In conclusion, DXS 5000 is an efficient complement inhibitor in pig-to-human xenotransplantation models and therefore a candidate for complement-inhibitory/anti-inflammatory therapy either alone or in combination with other substances and warrants further investigation.

Partial cricoidectomy with primary thyrotracheal anastomosis for postintubation subglottic stenosis

OBJECTIVE

We describe a Pearson-type technique and evaluate its results for postintubation subglottic stenosis.

METHODS

Forty-five patients underwent a partial cricoidectomy with primary thyrotracheal anastomosis, and 5 underwent simultaneous repair of a tracheoesophageal fistula as well. Twenty-four (53%) patients were referred to us after initial conservative (n = 21) or operative (n = 3) management. There were 27 cuff lesions, 7 stomal lesions, and 11 at both levels. The upper limit of the stenosis was 1.5 cm (range, 1-2.5 cm) below the cords, and the subglottic diameter was reduced by 60% in 38 (84%) of the patients. The length of airway resection ranged from 2 to 6 cm (median, 3 cm). Despite 23 thyrohyoid or suprahyoid releases, 8 anastomoses were under tension.

RESULTS

Thirty-seven (82%) patients were extubated after the operation (n = 30) or within 24 hours (n = 7). Six patients required postoperative airway stenting (median, 5.5 days). Early (<30 days) complications occurred in 18 (41%) patients, mainly as transient airway and voice complaints, aspiration, and dysphagia. One (2%) patient died of myocardial infarction. Late morbidities were 2 failures occurring as bilateral recurrent nerve paralysis and restenosis requiring definitive tracheostomy. Patients had excellent or good anatomic (n = 42 [96%]), functional (n = 41 [93%]), or both types of long-lasting results, with no stenotic relapse.

CONCLUSIONS

Partial cricoidectomy with primary thyrotracheal anastomosis can be applied in patients with postintubation stenosis extending up to 1 cm below the cords and measuring up to 6 cm in length with excellent-to-good definitive results. The association with a tracheoesophageal fistula does not contraindicate surgical repair.

Use of embryonic human trachea grown in nude mice to patch-repair congenital tracheal stenosis

BACKGROUND

Long congenital tracheal stenosis is a life-threatening condition, and the available surgical treatments do not give satisfactory long-term results.

METHODS

Human embryonic tracheas were implanted in the abdominal cavities of nude mice until their differentiation was completed. These differentiated tracheas were used to patch-repair surgically induced tracheal stenosis in piglets. The human, mouse, or pig origin, of all the cells in the two successive xenotransplants in the nude mouse and the pig, was determined on tissue sections by in situ hybridization with species-specific DNA probes.

RESULTS

The transplanted pigs thrived and reached normal adulthood, irrespective of the administration of immunosuppressive treatment. The human tracheal tissue developed in nude mice conserved human structures, with the exception of feeding capillaries, which were of mouse origin. The tracheal patch in the adult healthy pigs comprised only pig cells organized into a fibrous scar, which was covered by normal pig epithelium.

CONCLUSIONS

Results suggest that human embryonic trachea grown in nude mice can be successfully used as patch tracheoplasty for long congenital tracheal stenosis without conventional immunosuppression.

Factors affecting long-term survival after en-bloc resection of lung cancer invading the chest wall

OBJECTIVE

Several reports emphasize the importance of en-bloc resection as the optimal surgical treatment of lung cancer with chest wall invasion. We investigated possible factors which could affect long-term survival following radical resection of these tumors.

METHODS

Between 1981 and 1998, 100 patients (90 male; ten female), with a median age of 60 years (36-84), underwent radical en-bloc resection of non-small cell lung cancer (NSCLC) with chest wall involvement. Patients with superior sulcus tumors invading the thoracic inlet were excluded from this series. There were 43 squamous and 57 non-squamous tumors. The median number of resected ribs was three (1-5). Lung resection included 73 lobectomies, two bilobectomies, 18 pneumonectomies and seven segmentectomies. Chest wall resection also extended to the sternum in one patient, the transverse process in one, the costotransverse foramen and hemivertebrae in two. All patients had a complete resection. Sixty-three patients received postoperative radiotherapy and 12 received chemotherapy. Histological data, including differentiation and depth of chest wall invasion, were carefully reviewed. The effect of various factors on survival were studied.

RESULTS

There were four in-hospital deaths. Lymph node involvement was negative on surgical specimens in 65 patients, and 28 patients had positive N1 nodes; the final histology revealed seven N2 diseases. Chest wall invasion was limited to the parietal pleura in 29 patients and included intercostal muscles, bones and extrathoracic muscles in 67, 24 and seven cases, respectively. The overall 2-year survival rate was 41%. The 5-year survival for patients with N0, N1 and N2 disease was 22, 9 and 0%, respectively. A local recurrence occurred in 13 patients, with four having a new resection and 45 patients developing systemic metastases. The nodal status (N0-1 vs. N2; P=0. 026) and the number of resected ribs(<2 vs. >2; P=0.03) were survival predictors in univariate analysis. By multivariate analysis, the two independent factors affecting long-term survival were the histological differentiation (well vs. poorly differentiated; P=0. 01) and the depth of chest wall invasion (parietal pleura vs. others; P=0.024).

CONCLUSIONS

Histological differentiation and depth of chest wall involvement were the main factors affecting long-term survival in this series. The role of induction chemotherapy for tumors with poor prognosis should be investigated.

Transcervical-transtracheal endoluminal repair of membranous tracheal disruptions

Tracheal lacerations are rare and potentially hazardous complications of tracheal intubation. Surgical repair is the treatment of choice of tracheal injuries although nonoperative management is occasionally appropriate for well-selected patients. We describe our personal technique of anterior transcervical-transtracheal endoluminal suture of iatrogenic lacerations of the membranous trachea and our results with this approach in 8 patients. This method is less invasive than conventional cervical or transthoracic approaches.

Surgical treatment of pulmonary aspergilloma: current outcome

OBJECTIVE

This retrospective study was designed to confirm that aggressive pulmonary resection can provide effective long-term palliation of disease for patients with pulmonary aspergilloma.

METHODS AND RESULTS

From 1959 to 1998, 84 patients underwent a total of 90 operations for treatment of pulmonary aspergilloma in the Marie-Lannelongue Hospital. The mean follow-up period was 9 years, and 83% of the patients were followed up for 5 years or until death, if the latter occurred earlier. The median age was 44 years. The most common indications were hemoptysis (66%) and sputum production (15%). Fifteen patients (18%) had no symptoms. Tuberculosis and lung abscess were the most common underlying causes of lung disease (65%). The procedures were 70 lobar or segmental resections, 8 cavernostomies, and 7 pneumonectomies. Five thoracoplasties were required after lobectomy (3 patients) or pneumonectomy (2 patients). The operative mortality rate was 4%. The major complications were bleeding (23 patients), prolonged air leak (31 patients), respiratory failure (10 patients), and empyema (5 patients). The actuarial survival curve showed 84% survival at 5 years and 74% survival at 10 years. During the first 2 years, death was related to the surgical procedure and the underlying disease. In contrast, 85% of the survivors had a good late result.

CONCLUSION

Lobar resection in both the symptomatic and the asymptomatic patients was conducted in low-risk settings. For patients whose condition is unfit for pulmonary resection, cavernostomy may need to be undertaken despite the high operative risk. The better survival rate in this study may have been due to the selection of patients with better lung function and localized pulmonary disease.

Evaluation and outcome of different surgical techniques for postintubation tracheoesophageal fistulas

OBJECTIVE

We evaluated the outcome of different surgical techniques for postintubation tracheoesophageal fistula.

METHODS

Thirty-two consecutive patients aged 51 +/- 23 years had tracheoesophageal fistulas resulting from a median of 30 days of mechanical ventilation via endotracheal (n = 12) or tracheostomy (n = 20) tubes. Tracheoesophageal fistulas were 2.5 +/- 1.2 cm long and were associated with a tracheal (n = 10) or subglottic (n = 3) stenosis in 13 patients.

RESULTS

All but 3 patients were weaned from respirators before repair. All operations were done through cervical incisions and included direct division and closure (n = 9), esophageal diversion (n = 3), muscle interposition (n = 6), or, more recently, tracheal or laryngotracheal resection and anastomosis with primary esophageal closure (n = 14). Nine thyrohyoid and two supralaryngeal releases reduced anastomotic tension. Twenty-three patients (74%) were extubated after the operation (n = 16) or within 24 hours (n = 7), and 7 required a temporary tracheotomy tube. One postoperative death (3%) was associated with recurrent tracheoesophageal fistula. Seven complications (22%) included recurrent tracheoesophageal fistula (n = 1), delayed tracheal stenosis (n = 2), dysphagia (n = 2), and recurrent nerve palsy (n = 2). Complications necessitated reoperation (n = 1), dilation (n = 2), definitive tracheostomy (n = 1), Montgomery T tubes (n = 1), and Teflon injection of the vocal cords (n = 1). Twenty-nine patients (93%) had excellent (n = 24) or good (n = 5) anatomic and functional long-term results. Complications have been less common (7% vs 38%) and long-term results better (93% vs 65%) recently with tracheal or laryngotracheal resection and anastomosis with primary esophageal closure as compared with previous procedures.

CONCLUSIONS

Postintubation tracheoesophageal fistula is usually best treated with tracheal or laryngotracheal resection and anastomosis with primary esophageal closure even in the absence of tracheal damage.

A preclinical model for laryngeal transplantation: anatomy and mucosal immunology of the porcine larynx

BACKGROUND

A major step in translating work on laryngeal transplantation into clinical practice is the establishment of a preclinical model. We have investigated the anatomy and mucosal immunology of the porcine larynx in eight Minnesota Minipigs (12-37 weeks).

METHODS

Neck dissections were carried out and the vascular tree was mapped. Snap-frozen biopsies from epiglottis, supraglottis, glottis, and subglottis were prepared for conventional histology, immunohistochemistry (CD45), and single and two-color immunofluorescence (CD3, MHC-II, CD45).

RESULTS

The anatomy of the laryngeal skeleton was broadly similar to that of the human larynx. The blood supply is predominantly via the caudal thyroid vessels, with assistance from the cranial laryngeal artery. The porcine larynx is clearly highly immunologically active. Structured collections of leukocytes were found in the mucosal epithelium, around tubuloacinar glands, and occasionally in the submucosa. MHC-II and CD 3 cells were predominantly found within the epithelium. The highest densities of all cell types were observed in the epiglottis, tailing off caudally. The lowest densities were seen in the vocal cords.

CONCLUSIONS

The porcine larynx is both anatomically and immunologically similar to the human larynx and contains a high level of immunological organization. It presents an ideal preclinical model for laryngeal transplantation.

Surgical management of superior sulcus tumors

Superior sulcus tumor refers to any primary lung cancer presenting with constant pain in the nerve distribution of the eighth cervical, first and second thoracic nerve roots and Horner's syndrome caused by invasion of the stellate ganglion. The pain is steady, severe, and unrelenting, involving the shoulder, the vertebral margin of the scapula and ulnar distribution of the arm to the elbow and finally to the ulnar surface of the forearm, and the small and ring fingers of the hand (Pancoast-Tobias syndrome). Weakness and atrophy of the hand muscles can also occur as the lesions spreads to involve the first and second ribs and vertebrae. Radiologically, there is a small shadow at the extreme apex of the lung with rib and possible vertebral body invasion. Pulmonary symptoms are less frequent because of the peripheral location of the lesions. Since Shaw and Paulson approached superior sulcus tumors in 1961 by using preoperative radiation-therapy (30 to 45 Gy in four weeks including the primary tumor, mediastinum and supraclavicular region) followed by surgical resection, this radiosurgical approach shortly became the standard treatment yielding better disease control and survival than that offered by other treatment modalities. It has now become evident that en bloc resection of the chest wall, involved adjacent structures as well as lobectomy must be considered the standard surgical approach for superior sulcus tumors combined with external radiation (preoperative, postoperative, or both). The goal of the operation is the complete and en bloc resection of the upper lobe in continuity with the invaded ribs, transverse processes, subclavian vessels, T1 nerve root, upper dorsal sympathetic chain and prevertebral muscles.

Characterization of a pig-to-goat orthotopic lung xenotransplantation model to study beyond hyperacute rejection

BACKGROUND

A pig-to-goat orthotopic lung xenograft model was developed to test whether depletion of goat xenoreactive antibodies against pig red blood cells would prolong pig lung xenograft survival.

METHODS

Adult goats with anti-pig xenoreactive antibodies underwent left pneumonectomy followed by orthotopic transplantation of pig left lung (group 1) or immunodepletion of their xenoreactive antibodies by extracorporeal right pig lung perfusion before transplantation without (group 2) or with (group 3) complete clampage of the right pulmonary artery. In group 4, goat left lungs were orthotopically transplanted into pigs and served as negative controls (pig serum does not have anti-goat xenoreactive antibodies). Each study group included 5 animals. Immunosuppression in surviving recipients included cyclosporine and azathioprine.

RESULTS

Group 1 recipients died 7 +/- 3 hours after xenograft reimplantation of severe pulmonary hypertension and dysfunction and vasogenic shock, with little evidence of histologic xenograft injury. Group 2 xenografts had a stable circulatory and respiratory function on reperfusion and survived 9 +/- 4 days. Group 3 animals also tolerated complete occlusion of the right pulmonary artery, and xenografts assured the total respiratory support for 4 +/- 1 days. After immunodepletion, goat serum showed no detectable titers of xenoreactive antibodies, which began to reappear by postoperative day 2, where xenografts showed histologic stigmata of acute (humoral and cellular-mediated) rejection that evolved to a complete xenograft necrose at death. Group 4 xenografts showed scattered features of acute rejection 5 +/- 1 days after the operation.

CONCLUSIONS

Pig left lung xenografts can provide prolonged and complete respiratory support after depletion of goat xenoreactive antibodies, but they ultimately necrose once recipient xenoreactive antibodies return to pretransplantation values.

Angioscopic video-assisted pulmonary endarterectomy for post-embolic pulmonary hypertension

OBJECTIVES

To assess whether the use of video-assisted angioscopy would increase the outcome of pulmonary thromboendarterectomy (PTE).

METHODS

PTE included a median sternotomy, intrapericardial dissection of the superior vena cava, institution of cardiopulmonary bypass, deep hypothermia and sequential circulatory arrest periods. It was always performed through two separate arteriotomies on both main intrapericardial pulmonary arteries, into which a rigid 5 mm angioscope connected to a video camera was introduced to increase the visibility and endarterectomies.

RESULTS

From January 1996 to July 1998, 68 consecutive patients (35 males and 33 females) aged 54.3 +/- 13.5 years underwent PTE. Patients were in New York Heart Association (NYHA) class II (n = 2), III (n = 43) or IV (n = 23) with the following hemodynamics: mean pulmonary arterial pressure (PAP) 54 +/- 13 mmHg; cardiac output (CO): 3.8 +/- 0.8 l/min, and total pulmonary resistance (TPR): 1207 +/- 416 dyne x s x cm(-5). The cumulated circulatory arrest time was 23 +/- 12 min and postoperative length of ventilatory support 10 +/- 12 days. Nine patients died, for an overall in-hospital mortality of 13.2%. The functional outcome in surviving patients was significantly improved (P < 0.0001) both clinically (NYHA class 3.2 +/- 0.5 vs. 1.3 +/- 0.6) and hemodynamically (PAP (mmHg) 53.1 +/- 13 vs. 30.2 +/- 11.8, CI (l/min per m2) 2.1 +/- 0.5 vs. 2.8 +/- 0.6, TPR (dyne x s x cm(-5)) 1174 +/- 416 vs. 519 +/- 250).

CONCLUSIONS

Video-assisted angioscopy improves the quality and degree of pulmonary endarterectomy expanding the indications to include patients with previously inaccessible distal disease.

Techniques of pneumonectomy. Sleeve pneumonectomy

Sleeve pneumonectomy is a technically demanding procedure, the indications of which include non-small bronchogenic tumors extending to the tracheobronchial bifurcation without diseased mediastinal nodes. Right sleeve pneumonectomies are best approached through an ipsilateral thoracotomy in the fifth (or fourth) intercostal space. Median sternotomy for left sleeve pneumonectomy gives outstanding exposure to the tracheobronchial bifurcation, and less incisional discomfort and ventilatory restriction than an ipsilateral thoracotomy. If a tracheobronchial anastomosis is under tension, excessive tracheobronchial and mediastinal dissection and perioperative fluid overload are avoided, then the most common and often fatal early (noncardiogenic pulmonary edema) and late (anastomotic dehiscence) complications are significantly lowered. If these guidelines are respected, this operation generates 5-year survival rates exceeding 40%.

Experimental and clinical evaluation of a new synthetic, absorbable sealant to reduce air leaks in thoracic operations

BACKGROUND

Air leaks after pulmonary resections may contribute to increased patient morbidity, delayed removal of chest drainage tubes, and prolonged hospitalization.

OBJECTIVE

The purpose of this study was to investigate the effects of a new synthetic, absorbable sealant on the healing of healthy bronchial and lung tissues (experimental study) and its safety and efficacy to stop air leaks after lung resection (clinical study).

METHODS

Fifteen large white pigs underwent a left upper lobectomy. All parenchymal surgical sites were sealed; the bronchial stump was either stapled, sealed, or both (n = 5 each). In the clinical study, 26 consecutive patients were prospectively randomized, intraoperatively, to standard closure of parenchymal surgical sites with (n = 15) or without (n = 11) the sealant.

RESULTS

In the experimental study, no postoperative air leaks occurred, with intact bronchial closures and normal tissues at death. In the clinical study, 100% of intraoperative leaks were sealed versus 18% of control patients (P =.001). Although 77% (n = 10) of treated patients remained leak-free from the end of the operation to chest tube removal versus 9% (n = 1) of control patients (P =.001), there was no statistical difference in the duration of postoperative chest tube time, hospital stay, or cost. There were no acute or late undesirable side-effects related to the sealant application.

CONCLUSIONS

The surgical adhesive investigated here demonstrated a compelling safety profile and significant clinical efficacy to stop air leaks after lung resections.

Subclavian artery resection and reconstruction for thoracic inlet cancers

PURPOSE

We previously described an original transcervical approach to resect primary or secondary malignant diseases that invade the thoracic inlet (TI). The purpose of this study was to evaluate the technical aspects and long-term results of the resection and revascularization of the subclavian artery (SA).

METHODS

Between 1986 and 1998, 34 patients (mean age, 49 years) underwent en bloc resection of TI cancer that had invaded the SA. The surgical approach was an L-shaped transclavicular cervicotomy in 33 patients. In 14 of these patients, this approach was associated with a posterolateral thoracotomy (n = 10) or a posterior midline approach (n = 4). In one patient, the procedure was achieved with a single posterolateral thoracotomy approach. An end-to-end anastomosis was performed in 16 patients. In one patient, a subclavian-left common carotid artery transposition was performed. In one other patient, an end-to-end anastomosis was performed between the proximal innominate artery and the SA. The right carotid artery was transposed into the SA in an end-to-side fashion. In 16 patients, prosthetic revascularization with a polytetrafluoroethylene graft was performed. Thirty-three patients underwent postoperative radiation therapy.

RESULTS

There were no cases of perioperative death, neurologic sequelae, graft infections or occlusions, or limb ischemia. There were two delayed asymptomatic polytetrafluoroethylene graft occlusions at 12 and 31 months. The 5-year patency rate was 85%. During this study, 20 patients died: 18 died of tumor recurrence (5 local and systemic and 13 systemic), one of respiratory failure, and one of an unknown cause at 74 months. The overall 5-year survival rate was 36%, and the 5-year disease-free survival rate was 18%.

CONCLUSION

Tumor arterial invasion per se should not be a contraindication to TI cancer resection. This study shows that cancers that invade the SA can be resected through an L-shaped transclavicular cervicotomy, with good results with a concomitant revascularization of the SA.

Clamshell or sternotomy for double lung or heart-lung transplantation?

OBJECTIVE

To evaluate the influence of either incision on the lungs and chest wall.

METHODS

Ninety-two double lung (DLT) or heart-lung (HLT) transplantations were done since January 1990. There were 22 (24%) hospital deaths, leaving 70 patients with complete data for evaluation. We did 38 DLT and 32 HLT for end-stage chronic respiratory failure (n = 22) and primary (n = 34) or secondary (n = 14) pulmonary hypertension, using 37 fourth or fifth interspace clamshell incisions and 33 median sternotomies.

RESULTS

The clamshell group included a higher percentage of DLTs (73 vs. 33%, P = 0.001) but recipient age, gender, preoperative diagnosis, bronchial anastomotic complications, number of cytomegalovirus infection, episode of acute rejection per patient-months and incidence of bronchiolitis obliterans were not statistically different between the two groups. At a follow-up time of 3.7 +/- 2 years, the overall 5-year survival of 57% was not influenced by the type of incision. The clamshell incision caused sternal over-riding in 12 (32%) patients, and eight surgical clamshell revision were necessary as compared with one median sternotomy (P = 0.02). The clamshell incision was associated with a significantly higher incidence of postoperative chronic pain (27 vs. 6%, P = 0.02). Postoperative mechanical properties of the chest wall were significantly (P < 0.0001) worse in the clamshell-group patients while the intrinsic properties of the airways were not different.

CONCLUSIONS

The clamshell incision results in more postoperative deformity, chronic pain, and impaired function as compared with median sternotomy. A bilateral anterolateral thoracotomy without division of the sternum is proposed for the sequential bilateral lung transplantation technique.

Evidence of human non-alpha-galactosyl antibodies involved in the hyperacute rejection of pig lungs and their removal by pig organ perfusion

BACKGROUND

Human natural xenoantibodies represent a major hurdle to the clinical application of pig lungs in transplantation by initiating hyperacute rejection within minutes to hours.

OBJECTIVE

The object was to compare pig organ perfusion and specific depletion of anti-alpha-galactosyl xenoantibodies for prevention of hyperacute rejection in the pig to human lung combination.

METHODS

Large White pig (20-25 kg) left lungs were removed and continuously ventilated and reperfused ex vivo either with (1) whole human blood previously perfused in situ through pig right lung (group I), liver (group II), or spleen (group III) or with (2) human plasma in vitro immunoabsorbed on columns containing alpha-galactosyl disaccharide (Gal-alpha-(1-3)Gal-beta-(CH2)3NH2; B disaccharide) (group IV). Each study group included 6 animals.

RESULTS

The in situ and in vitro preperfusions depleted anti-alpha-galactosyl xenoantibodies and all in situ perfused pig organs showed histologic signs of hyperacute rejection. After the ex vivo reperfusion, group I xenografts had a significantly (P < .001) longer functional and histologic survival than did xenografts in groups II, III, and IV. Human blood reperfusing group I xenografts had a significantly (P < 0.05) lower (1) decline of clotting factors and total circulating immunoglobulins, (2) total and membrane attack complex (C5b,6,7,8,9) complement activation, and (3) hemolysis. By Western blot analysis, the in situ lung preperfusion removed antibodies against non-alpha-galactosyl proteins of low molecular weight that were not eliminated by the alpha-galactosyl column.

CONCLUSIONS

Results demonstrate that specific depletion of anti-alpha-galactosyl antibodies alone incompletely protects pig lungs from hyperacute rejection. It is speculated that the more complete prevention of this rejection afforded by pig lung preperfusion relates to the removal of other, non-alpha-galactosyl antibodies.

Surgery for invasive primary mediastinal tumors

BACKGROUND

There have been few reports on results after extended radical resection for primary mediastinal tumors invading neighboring organs.

METHODS

A retrospective analysis of 89 patients who underwent total or subtotal resection of a primary mediastinal tumor with resection of at least part of an adjacent structure between 1979 and 1995 was performed. Clinical data were collected from the medical records.

RESULTS

There were 35 invasive thymomas, 12 thymic carcinomas, 17 germ cell tumors, 16 lymphomas, 3 neurogenic tumors, 3 thyroid carcinomas, 2 radiation-induced sarcomas, and 1 mediastinal mesothelioma. The tumor was located in the anterior mediastinum in 74% of patients. Residual masses after chemotherapy were excised in 14 patients with germ cell tumor and 8 with lymphoma. A median sternotomy was the most frequently used approach (79% of patients). Total resection was achieved in 79% and significantly improved survival (p < 0.01). Adjacent resected structures included 38 phrenic nerves, 21 superior venae cavae, 16 upper lobes, and 13 innominate veins, in 5 patients, a pneumonectomy was required. The complication rate was 17% and the mortality rate, 6%. With follow-up available for 86 patients, the overall 5-year survival rate was 69% for patients with thymoma, 42% for patients with thymic carcinoma, 48% for patients with germ cell tumor, and 83% for patients with lymphoma.

CONCLUSIONS

Malignant mediastinal tumors can be safely resected even if they have invaded other mediastinal structures. Complete resection is important to achieve satisfactory long-term survival. A median sternotomy is an excellent approach, and a preoperative diagnosis by biopsy is desirable. Residual masses after chemotherapy for lymphoma or germ cell tumor should be resected. Extensive resection without a preoperative diagnosis is not indicated.

Tracheoplasty in congenital tracheal stenosis

Congenital tracheal stenosis is an uncommon but life-threatening condition whose management is still debated. The rarity of this disease explains the lack of a standard management. Between 1986 and 1996, eight children younger than 1 year were referred to our Institution with a tracheal stenosis. The median age at operation was 3.15 months and the median weight was 4.5 kg. The diagnosis was made after an episode of respiratory distress in all but one and was confirmed by fiberoptic bronchoscopy. The median length of tracheal stenosis was 24.5 mm (Ranges: 4-30 mm). Only one patient was free from associated cardiovascular defect. Tracheal repair was performed under cardiopulmonary bypass in all. In three it was achieved by pericardial augmentation of the stenosed area, in four by resection and end to end anastomosis and in one by sliding tracheoplasty. Concomitant cardiac repair was performed in six. Two patients died after pericardial patch augmentation. In both, death was related to profound hypoxemia due to patch collapse. Two patients developed restenosis after resection and end to end anastomosis. They both had stent placement and one required reoperation and underwent a sliding tracheoplasty. At a median follow-up of 21 months (Ranges: 6-120) all the survivors are doing well and are free from respiratory symptoms. Bronchoscopic evaluation revealed in all a widely patent anastomosis without restenosis. In conclusion, tracheal stenosis in children remains a challenging lesion. Surgical technique, whether resection and end to end anastomosis or sliding tracheoplasty offer better results and should be discussed according to the length of the stenosis. Pericardial plasty should be used with caution.

[Pulmonary thromboendarterectomy with video-angioscopy and circulatory arrest: an alternative to cardiopulmonary transplantation and post-embolism pulmonary artery hypertension]

The best predictor of poor or suboptimum outcome from pulmonary thromboendarterectomy (PTE) is insufficient relief of obstruction, especially in the lower lobes. The aim of this study is to emphasize that the use of video-assisted angioscopy may increase the quality of PTE and thus improve outcome. PTE included a median sternotomy, intrapericardial dissection limited to the superior vena cava, institution of cardiopulmonary bypass, deep hypothermia and sequential circulatory arrest periods. PTE was always bilateral and performed through two separate arteriotomies of both main intrapericardial pulmonary arteries. A rigid 5 mm angioscope connected to a video camera was introduced through the arteriotomy into the lumen to increase the visibility and perform the video-assisted endarterectomies of all obstructed segmental branches, including normally inaccessible anterior segmental branches. Between January 1996 and December 1997, 48 patients with severe postembolic pulmonary hypertension had PTE. Patients were in New York Heart Association (NYHA) class II (n = 2), III (n = 28) or IV (n = 18) with the following hemodynamics: mean pulmonary arterial pressure (PAP) 53 +/- 13 mmHg, cardiac index 2.16 +/- 0.5 L/min/m2, pulmonary vascular resistances (PVR): 1,152 +/- 414 dyne.s-1.cm-5. Six patients died from alveolar hemorrhage (n = 1), high residual pulmonary pressure and rethrombosis (n = 4) and hypoxic cardiac arrest (n = 1). The functional outcome in surviving patients was as follows: (NYHA) class I (n = 24), II (n = 16) or III (n = 2) with improved hemodynamics: mean pulmonary arterial pressure: 30 +/- 9 mmHg, cardiac index: 2.78 +/- 0.5 L/min/m2, pulmonary vascular resistances (PVR): 484 +/- 159 dynes.s-1.cm-5. Video-assisted angioscopy allows much improved quality and degree of pulmonary endarterectomy. This expands the indications to include patients with previously inaccessible distal disease and candidates for heart-lung transplantation.

Ex vivo lung model of pig-to-human hyperacute xenograft rejection

OBJECTIVE

Our objective was to study lung hyperacute rejection in the pig-to-human xenotransplantation combination.

METHODS

Pig lungs were harvested and continuously ventilated and perfused ex vivo, using a neonatal oxygenating system, with either xenogeneic unmodified human blood (n = 6) or autogeneic pig blood (n = 6).

RESULTS

Autoperfused lungs displayed normal hemodynamics, oxygen extraction (arteriovenous oxygen difference), and histologic characteristics throughout the 3-hour study period. By contrast, xenoperfused lungs displayed, within 30 minutes, severe pulmonary hypertension and abolishment of arteriovenous oxygen difference culminating in massive pulmonary edema, hemorrhage, and lung failure after 115 +/- 44.2 minutes of reperfusion. Within 30 minutes, the human blood showed a significant drop of anti-alpha Gal immunoglobulin M and G xenoreactive antibodies (enzyme-linked immunosorbent assay) and complement activity, consumption of clotting factors, and hemolysis; total circulating human immunoglobulins remained substantially normal. Histologically, lungs perfused with human blood were congestive and showed alveolar edema and hemorrhage and multiple fibrin and platelet thrombi obstructing the small pulmonary vessels (arterioles, capillaries, and venules) but not large (segmental or lobar) pulmonary vessels. On immunohistologic examination, deposits of human immunoglobulin M and complement (C1q and C3) proteins were observed on the alveolar capillaries.

CONCLUSIONS

This pig-to-human xenograft model suggests that the pig lung perfused with human blood has an early and violent hyperacute rejection that results in irreversible pulmonary dysfunction and failure within approximately 150 minutes of reperfusion.

Tracheal growth after slide tracheoplasty

OBJECTIVE

Our goal was to investigate the effects of slide tracheoplasty on tracheal growth in newborn piglets.

METHODS

Slide tracheoplasty was performed on normal trachea (n = 6) and a model of tracheal stenosis resembling that seen in infants (n = 6). After division of the trachea at its midportion between the second cartilaginous ring above and the right upper lobe takeoff below (around 23 rings), the proximal and distal segments were incised vertically on opposite anterior and posterior surfaces and reconstructed together.

RESULTS

The reconstructed tracheas lengthened and their cross-sectional areas enlarged linearly at a rate of 0.94 cm per month and 1.55 mm2/kg, respectively, as the piglets grew over a 6-month period from 4.7 +/- 0.6 to 64.4 +/- 5.7 kg (+/- standard deviation). Growth was not different between the two studied groups. There was no narrowing or late restenosis. The mean anastomotic cross-sectional area was overall 1.63 +/- 0.28 times larger (range 1.2 to 2.7) than the cross-sectional area of the unreconstructed trachea. When the animals were put to death, all tracheal lumina were completely lined with normal respiratory epithelium and all layers were histologically intact; anastomotic trachealis muscles contracted less (p < 0.001) but relaxed similarly to those muscles lining normal tracheas. Tracheal blood supply was macroscopically and microscopically normal in both groups; however, newborn piglets had an almost twofold increased number of intramural capillary vessels as opposed to adult pigs (p < 0.001).

CONCLUSIONS

Results suggest that slide tracheoplasty is not limited by the length of stenosis, provides a permanent enlargement of the cross-sectional airway diameter, does not compromise tracheal vascular supply, and does not impair tracheal growth as somatic growth continues.

Radical resection of radiation-induced sarcoma of the chest wall: report of 15 cases

BACKGROUND

Surgical management of radiation-induced sarcoma of the chest wall remains difficult because of its impressive local aggressiveness.

METHODS

Between 1987 and 1995, 15 patients (median age, 58 years) underwent radical resection of radiation-induced sarcoma of the chest wall. This type of tumor was defined as a metachronous, histologically different neoplasm in the irradiated field of the original tumor. Ten patients had a history of primary breast cancer and 5 patients, Hodgkin's disease. The median delivered radiation dose to the primary tumor area was 45 Gy, and the median interval between radiotherapy and diagnosis of sarcoma was 14 years. Seven tumors were located on the sternum, three on the lateral chest wall, and five in the thoracic outlet. Four total and three partial sternectomies, three lateral chest wall resections and five resections of tumors in the thoracic outlet (three first-rib resections) were performed. Seven patients required stabilization of the chest wall with prosthetic material. Soft tissue reconstruction was carried out with either muscle flaps and skin advancement in 9, musculocutaneous flaps in 4, or skin flaps alone in 2 patients.

RESULTS

One patient died 3 months after total sternectomy of respiratory failure. Two patients (13.3%) had a local complication: sepsis after sternectomy in 1 and cutaneous necrosis in 1. Local recurrence occurred in 7 patients after a median interval of 10 months. Two of them died, and 4 underwent a repeat resection, 3 of whom are still alive. Four patients died of systemic recurrence. With a median follow-up of 30 months, overall 5-year survival and 5-year disease-free survival rates were 48% and 27%, respectively.

CONCLUSION

Despite poor long-term disease-free survival, radical resection of radiation-induced sarcoma of the chest wall is justified on the basis of low postoperative morbidity and the lack of other available therapies.

Management of acquired tracheoesophageal fistula

Acquired, nonmalignant tracheoesophageal fistulae usually result from erosion of the tracheal and esophageal walls by endotracheal or tracheostomy tube cuffs, especially when a rigid nasogastric tube is in place. This has become an infrequent occurrence with the use of high-volume, low-pressure cuffs, but it still represents a life-threatening condition. Spontaneous recovery is exceptional. Most are diagnosed while patients still are mechanically ventilated and, due to the negative effects of positive pressure ventilation on tracheal suture lines, repair should be delayed until patients are weaned. After the patients is weaned from the ventilator, a one-staged anterior approach including esophageal closure, segmental tracheal resection, and primary reconstruction definitely corrects the fistula and removes concurrent tracheal disease and should be preferred to simple division and closure of the fistula.

Carinal resection for bronchogenic cancer

Traditionally, high technical morbidity and mortality and uncertain long-term survival have been associated with carinal surgery for bronchogenic carcinoma. However, growing evidence exists that judicious indications, meticulous surgery, and also perioperative management can decrease surgical mortality. Contraindications include patients whose tumors are so extensive that reconstruction would be under tension and those with involved precarinal and paratracheal nodes. Patients with diseased subcarinal nodes might benefit from surgery. Right carinal pneumonectomy is the most common carinal procedure, and the safe limit of resection is approximately 4 cm between the lower trachea and contralateral main bronchus. Small lesions involving the carina only may be resected without pulmonary resection with somewhat greater resectional limits. Right upper lobe tumors involving the carina may also be completely resected by saving the right middle and lower lobes and fashioning a new carina. Fatal early (noncardiogenic pulmonary edema) and late (anastomotic dehiscence or separation) complications after carinal pneumonectomy may be preventable by limiting mediastinal lymphatic dissection and perioperative intravascular fluid overload. A limited tailored thoracoplasty and transposition of the latissimus and serratus muscles into the postpneumonectomy pleural space can mitigate anastomotic complications. If these recommendations are respected, the technical mortality rates of carinal pneumonectomy can equal those observed after conventional pneumonectomy, and 5-year survival rates in excess of 40% can be expected for NO-1 patients. Invasion of the carina by bronchogenic carcinoma should not be considered by itself a surgical contraindication because the potential for cure is not elusive.

[Intrathoracic goiters. 62 surgically treated patients]

OBJECTIVES

Intrathoracic goitres present as tumors of the upper mediastinum. Malignancy is uncommon, but sudden or progressive development often leads to compression of the trachea. We report here our experience with surgical exeresis.

METHODS

From 1980 to 1995, we operated 62 patients with intrathoracic goitre. There were 23 men and 39 women (mean age 63 years). The main manifestations leading to diagnosis were dyspnea (n = 20; 32%) and identification of a mediastinal formation on routine chest x-rays (n = 19; 30%).

RESULTS

Antevascular goitre was seen in 24 patients (39%) and retrovascular goitre in 38 (61%). The retrovascular goitres were located anteriorly and laterally to the trachea in 21 patients (34%) and posteriorly in 17 (27%). Simple cervicotomy was used in 57 patients (92%). Manubriotomy (n = 1) and total sternotomy (n = 4) were also required. All intrathoracic goitres removed were benign. Post-operative mortality was nul and morbidity was 11%: 2 cases of hypocalcemia and 2 tracheomalacias including 1 with recurrent nerve palsy and one with hematoma and pulmonary infection.

CONCLUSION

Surgical exeresis of intrathoracic goitre is essentially required in case of respiratory distress due to compression of the trachea. Morbidity is low with simple cervicotomy.

Thymic neuroendocrine carcinoma (carcinoid): a clinicopathologic study of fourteen cases

The medical records and histologic documents of 14 patients treated at our institution for a thymic carcinoid tumor were reviewed. There were 3 women and 11 men with an age range from 35 to 71 years. One patient had a multiple endocrine neoplasia syndrome; another had a neurofibromatosis. Twelve tumors were revealed by local symptoms and two were asymptomatic. One patient had Cushing's syndrome that appeared secondarily and was related to metastases. Tumors ranged from 6 to 20 cm and had the characteristic histologic appearance of atypical carcinoid tumor. Immunohistochemical evaluations were done. Tumors were positive for cytokeratin (92%), neuroendocrine markers (100%), and p53 oncoprotein (29%). S-100 protein antibody revealed numerous sustentacular cells in one case. Overall survival was 46% and 31% at 3 and 5 years, respectively. However, all patients died of the disease within 109 months as a result of local progression (n = 5), local relapse (n = 3), distant metastases (n = 8), or a combination of these reasons. Median survival was 71, 30, and 5 months for patients who had total resection (n = 4), partial resection (n = 5), or simple biopsy (n = 4), respectively (p = 0.023). In conclusion, thymic carcinoid tumors can be considered thymic neuroendocrine carcinomas because of their malignant behavior and histologic appearance of atypical carcinoid tumors. Complete surgical resection offers the best hope for long-term survival.

Large bilateral pulmonary artery aneurysms in Behçet's disease: rupture of the contralateral lesion after aneurysmorrhaphy

An 18-year-old man presented with Behçet's disease and two large bilateral pulmonary artery aneurysms. The day following aneurysmorrhaphy of the right aneurysm, a massive hemoptysis led to death. Postmortem examination disclosed rupture of the left aneurysm in a segmental bronchus. The aneurysms had inflammatory walls and were associated with organized pulmonary arterial thromboses and endomyocardial fibrosis of the right ventricle. Our case report highlights the surgical risk of rupture of associated arterial lesions, certainly related to per- and postoperative pulmonary arterial pressure variations.