Biomedical subjects

Agathe Seguin

Publications and source records attributed to Agathe Seguin.

4 recordsLinked to original sources

PubMed2006

Carinal replacement with an aortic allograft.

BACKGROUND: Carinal replacement after extensive resection remains a tremendous challenge in thoracic surgery. In previous studies, we demonstrated that an aortic graft could be a valuable tracheal substitute. The goal of this new study was to evaluate the reconstruction of the carina using a stent supported bifurcated aortic allograft. METHODS: In 15 sheep the replacement of the tracheobronchial bifurcation with an aortic allograft was performed under cardiopulmonary bypass. A temporary stent prevented airway collapse. No immunosuppression was used. Aortic segments were retrieved at regular intervals up to 24 months after implantation. RESULTS: All animals survived the initial aortic allograft operation. Six animals died postoperatively (1 of graft necrosis, 2 of pneumonia, and 3 of bronchial fistula). The remaining 9 animals were in good condition until they were euthanized. Stent removal was tolerated after 9 months in 3 animals. Progressive transformation of the arterial graft initially into extensive inflammatory tissue, and after 3 to 6 months into a tracheal tissue comprising a well-differentiated epithelium and cartilage was confirmed by histology. CONCLUSIONS: This study showed that regeneration of a functional tissue can be obtained after replacement of the carina with an aortic allograft. The origin and mechanisms of this regenerative process remains to be discovered. These results represent an important hope for the reconstruction of the carina after extensive resection, especially for cancer lesions. In human application, the systemic use of omentoplasty or myoplasty should further reduce its risk of complication.

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PubMed2005

Early and long-term results of lung resection for non-small-cell lung cancer in patients with severe ventilatory impairment.

OBJECTIVE: To study clinical characteristics, surgical treatment modalities, early and long-term outcome of patients with severe ventilatory impairment undergoing lung resection for NSCLC. METHODS: We performed a retrospective review of clinical records of all patients with severe chronic ventilatory impairment (FEV1 and/or FVC< or =50% of predicted values) operated on for NSCLC in a 21-year period (1983-2003). RESULTS: One hundred and six patients were operated on. Mean FEV1 and FVC were 40% (range 23-50%) and 69% (17-117%), respectively. An obstructive pattern was observed in 87 cases (82%). Extent of maximal exeresis was based on the assessment of predicted post-operative FEV1 (ppoFEV1). Major resections were contraindicated if ppoFEV1 was lower than 30%. Sixteen pneumonectomies, 73 lobectomies and 17 sublobar resections were carried out. Pathologic stages were I, II, IIIA and IIIB in 58, 26, 18 and 4 cases, respectively. Resection was complete in 104 patients. Operative mortality and morbidity were 8.5% (n=9) and 70% (n=74), respectively. Twenty-two patients needed prolonged (>48 h) mechanical ventilation. Overall mean ppoFEV1 loss was 9.1% (0-34%). If ppoFEV1 loss was >15%, the morbidity rate was 100%. Mean PaCO2 and ppoFEV1 loss were higher among patients who died (41 mmHg versus 37 mmHg, P=0.02 and 13.2% versus 8.5%, P=0.025, respectively) as compared with operative survivors. Among patients with PaCO2>39 mmHg and ppoFEV1 loss>15% (n=9), mortality rate was 33%. Overall 1-year and 5-year survival rates were 82 and 33%, respectively. Respiratory failure was the cause of late death in 2 patients. Among patients available at follow-up (n=85), respiratory function was considered subjectively improved, stable and worsened in 6 (7%), 62 (73%) and 17 (20%) cases, respectively. Eleven patients needed continuous oxygen therapy. CONCLUSIONS: Lung resection should not be denied a priori in patients with severe ventilatory impairment. Evaluation of predicted post-operative function often allows major resections, which are functionally economic, at the price of a high operative morbidity. Operative mortality, long-term survival and respiratory function are acceptable in the absence of a valid therapeutic alternative.

Aged↗

PubMed2005

Tracheal regeneration following tracheal replacement with an allogenic aorta.

BACKGROUND: Tracheal replacement remains an unsolved surgical problem. Attempts to use tracheal substitutes have failed to achieve reliable results. In this study, tracheal regeneration was obtained after tracheal replacement with an allogenic aorta. METHODS: Twenty female sheep underwent a 8-cm tracheal replacement with a fresh aortic allograft. In the six last animals, aortic grafts came from male sheep. A stent prevented airway collapse. No immunosuppressive therapy was used. Aortic segments were retrieved at regular intervals up to 16 months. A polymerase chain reaction for the SRY gene was performed in specimens with aortic grafts from male sheep. RESULTS: All animals but one survived the operation without complications. Clearly identified between the suture lines, the aortic segments were completely transformed into a tracheal structure. Histology showed initially an inflammatory reaction with proliferation of a squamous epithelium followed by mucociliary epithelium and newly formed cartilage rings. SRY gene was not found in newly formed cartilage rings showing that the regeneration originated from recipient cells. CONCLUSIONS: This study presents a new type of tissue regeneration and brings hopes to the treatment of extensive tracheal lesions.

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PubMed2003

Long-term evaluation of the replacement of the trachea with an autologous aortic graft.

BACKGROUND: Tracheal reconstruction after extensive resection remains a challenge in thoracic surgery. The goal of this experimental study was to analyze the long-term evolution of tracheal replacement using an autologous aortic graft. METHODS: In 21 sheep, a 5-cm segment of the cervical trachea was replaced by a segment of the descending thoracic aorta that was reconstructed to a prosthetic graft. Because of the airway collapse reported in a previous series, a permanent (n = 13) or temporary (n = 8) stent was systematically placed in the lumen of the graft. Clinical, bronchoscopic, and histologic examinations were performed up to 3 years after implantation. RESULTS: All animals survived the operation with no paraplegia. In the group with a permanent stent, three complications occurred: one stent displacement, one laryngeal edema, and one infection. Stent removal was tolerated after 6 months in the group with a temporary stent. Histologic examination showed a progressive transformation of the arterial segment into first extensive inflammatory tissue with a squamous epithelium, and after 6 to 36 months well-differentiated tracheal tissue including a continuous mucociliary epithelium and regular rings of newly formed cartilage. CONCLUSIONS: An autologous aortic graft used as a substitute for extensive tracheal replacement in sheep remained functional for periods up to 3 years. The progressive transformation of the graft into a structure resembling tracheal tissue seems to be a key factor in long-term patency. The mechanism of this regenerative process and the possibility of using arterial homografts, which would make clinical application easier, remain to be evaluated.

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