Cerebral ischemia during carotid artery cross-clamping: predictive value of phase-contrast magnetic resonance imaging.

The goal of this prospective study was to determine the utility of preoperative cerebral magnetic resonance imaging (MRI) in predicting cerebral ischemia during carotid artery cross-clamping for endarterectomy. Between January 2000 and December 2003, a total of 121 patients (95 men, 26 women) underwent three-dimensional phase-contrast MRI to assess collateral function prior to carotid endarterectomy. During regional anesthesia, patients were monitored to detect ischemic events and their timing in relation to cross-clamping and to determine mean intraoperative arterial pressure. These findings were then correlated with the collateral variations observed in the circle of Willis on preoperative MRI. Patients were classified into three groups according to neurological tolerance: normal tolerance (n = 106), immediate severe deficit (n = 9), and late deficit associated with arterial hypotension (n = 6). In the second group, a significant correlation was found between the absence of collateral circulation and neurological deficit (p < .0001). These results indicated that three-dimensional phase-contrast MRI is useful for predicting cerebral ischemia during carotid cross-clamping and selecting indications for shunting. Absence of visible collaterals of the circle of Willis on MRI is significantly predictive of early ischemia and an indication for systematic shunt placement.

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.

Tracheal replacement with an aortic autograft.

Tracheal replacement after extensive resection remains a challenge for the thoracic surgeon. We propose an innovative solution: the use of an aortic autograft. After an experimental work on animals with aortic autografts and allografts [Martinod E, Seguin A, Pfeuty K, Fornes P, Kambouchner M, Azorin JF, Carpentier AF. Long-term evaluation of the replacement of the trachea with an autologous aortic graft. Ann Thorac Surg 2003;75(5):1572-8; Martinod E, Seguin A, Holder-Espinasse M, Kambouchner M, Duterque-Coquillaud M, Azorin JF, Carpentier AF. Tracheal regeneration following tracheal replacement with an allogenic aorta. Ann Thorac Surg 2005;79(3):942-8], we present the first human case of long tracheal replacement with an aortic autograft. In this case we replaced 7 cm of a tumoral trachea using an aortic infra-renal autograft supported by a silicone stent. The early postoperative course was uneventful. The stent was removed at three months. The patient died at six months from an acute pulmonary infection without any sign of anastomosis leakage or graft rupture. A new field of clinical study has to be investigated.

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.

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.

Surgical resection of lung cancer in patients with underlying interstitial lung disease.

BACKGROUND: The association between interstitial lung disease (ILD) and an increased risk of developing lung cancer has been reported. The goal of this retrospective study was to determine the outcome of lung cancer resection among patients with ILD. METHODS: Between January 1979 and March 1999, 27 patients with both lung cancer and ILD were identified. Seven patients with poor pulmonary function tests or distant metastases underwent medical treatment and were excluded from this study. Twenty patients treated by surgical resection were analyzed. RESULTS: Various types of ILD such as sarcoidosis (n = 7), idiopathic interstitial pneumonia (n = 4), histiocytosis X (n = 4), pneumoconiosis (n = 4), and amiodarone-induced ILD (n = 1) were observed. Tumors were located in the peripheral part of the lung in 16 cases. The most frequent tumor cell types were squamous and adenocarcinoma. The resections consisted of lobectomy (n = 16), bilobectomy (n = 1), and pneumonectomy (n = 3). Most cancers were stage I (n = 10) or II (n = 6). There was no postoperative death. The postoperative course was uneventful in 16 cases. The majority of patients (70%) did not experience respiratory insufficiency during the follow-up period. The actuarial 2-year and 5-year survival rates were, respectively, 83.5% and 66.4%. CONCLUSIONS: In this series, the long-term survival of patients who had lung cancer resection appeared to be not affected by the association with ILD. This could be explained by an adequate preoperative selection based on pulmonary function tests and a preferential choice for lobectomies. Thus, surgical resection should be offered to properly selected patients with lung cancer and underlying ILD.

Management of superior sulcus tumors: experience with 139 cases treated by surgical resection.

BACKGROUND: The management of non-small cell carcinomas of the lung involving the superior sulcus remains controversial. The goal of this retrospective study was to evaluate the role of surgery, radiotherapy, and chemotherapy for the treatment of superior sulcus tumors, to define the best surgical approach for radical resection, and to identify factors influencing long-term survival. METHODS: Between 1983 and 1999, 139 patients underwent surgical resection of superior sulcus tumors in seven thoracic surgery centers. According to the classification of the American Joint Committee, 51.1% of cancers were stage IIB, 13.7% stage IIIA, 32.4% stage IIIB, and 2.9% stage IV. RESULTS: The resections were performed with 74.1% using the posterior approach and 25.9% using an anterior approach. A lobectomy was accomplished in 69.8% of the cases and a wedge resection in 22.3%. Resection of a segment of vertebrae or subclavian artery was performed, respectively, in 19.4% and 18% of the cases. Resection was complete in 81.3% of cancers. The overall 5-year survival rate was 35%. Preoperative radiotherapy improved 5-year survival for stages IIB-IIIA. Surgical approach, postoperative radiotherapy, or chemotherapy did not change survival. CONCLUSIONS: The optimal treatment for superior sulcus tumors is complete surgical resection. The surgical approach (anterior/posterior) did not influence the 5-year survival rate. Preoperative radiotherapy should be recommended to improve outcome of patients with a superior sulcus tumor.