Rachid Zegdi

Is It Reasonable to Treat All Calcified Stenotic Aortic Valves With a Valved Stent?: Results From a Human Anatomic Study in Adults

OBJECTIVES This study was designed to study the behavior of a stent deployed inside human stenotic aortic valves. BACKGROUND Endovascular valved stent (VS) implantation is a promising new therapy for patients with severe calcific aortic stenosis (AS). The precise characteristics of stent deployment in humans have been poorly studied so far. METHODS Thirty-five patients with severe AS were included in the study. Sixteen patients (46%) had bicuspid aortic valves. A self-expandable stent specifically designed for VS implantation was deployed intraoperatively inside the aortic valve before surgical aortic valve replacement. RESULTS In tricuspid aortic valves, the shape of stent deployment was circular, triangular, or elliptic in 68%, 21%, or 11%, respectively. Noncircular stent deployment was frequent in bicuspid aortic valves (the elliptic deployment being the rule [79%]), and stent underdeployment was constant. The incidence of gaps between the stent external surface and the aortic valve did not differ between tricuspid and bicuspid valves (58% vs. 43%; p = 0.49). Sharp calcific excrescences protruding inside the stent lumen were present in 3 cases (9%). Ex vivo study of a homemade VS confirmed that the regularity of the coaptation line of the leaflets was critically dependent on the presence or the absence of stent misdeployment. CONCLUSIONS Stent misdeployment was constant in bicuspid valves and occurred in one-third of cases of tricuspid valves. Premature failure of implanted VS (secondary to valve distortion or traumatic injury to the leaflets by calcific excrescences) might be an important concern in the future.

Ultrasonographic Diagnostic Criterion for Severe Diaphragmatic Dysfunction After Cardiac Surgery

BACKGROUND Severe diaphragmatic dysfunction can prolong mechanical ventilation after cardiac surgery. An ultrasonographic criterion for diagnosing severe diaphragmatic dysfunction defined by a reference technique such as transdiaphragmatic pressure measurements has never been determined. METHODS Twenty-eight patients requiring mechanical ventilation > 7 days postoperatively were studied. Esophageal and gastric pressures were measured to calculate transdiaphragmatic pressure during maximal inspiratory effort and the Gilbert index, which evaluates the diaphragm contribution to respiratory pressure swings during quiet ventilation. Ultrasonography allowed measuring right and left hemidiaphragmatic excursions during maximal inspiratory effort. Best E is the greatest positive value from either hemidiaphragm. Twenty cardiac surgery patients with uncomplicated postoperative course were also evaluated with ultrasonography preoperatively and postoperatively. Measurements were performed in semirecumbent position. RESULTS Transdiaphragmatic pressure during maximal inspiratory effort was below normal value in 27 of the 28 patients receiving prolonged mechanical ventilation (median, 39 cm H(2)O; interquartile range [IQR] 28 cm H(2)O). Eight patients had Gilbert indexes <or= 0 indicating severe diaphragmatic dysfunction. Best E was lower in patients with Gilbert index <or= 0 than > 0 (30 mm; IQR, 10 mm; vs 19 mm; IQR, 7 mm, respectively; p = 0.001). Best E < 25 mm had a positive likelihood ratio of 6.7 (95% confidence interval [CI], 2.4 to 19) and a negative likelihood ratio of 0 (95% CI, 0 to 1.1) for having a Gilbert index <or= 0. None of the patients with uncomplicated course had Best E < 25 mm either preoperatively or postoperatively. CONCLUSIONS Ultrasonographic-based determination of hemidiaphragm excursions in patients requiring prolonged mechanical ventilation after cardiac surgery may help identify those with and without severe diaphragmatic dysfunction as defined by the Gilbert index.

Long-Term Results of Mitral Valve Repair in Active Endocarditis

Background—Several investigators have reported the feasibility of mitral valve repair in active endocarditis, but the long-term results are still unknown. Methods and Results—We reviewed 37 consecutive patients who underwent mitral valve repair with the Carpentier technique for active endocarditis in our center between 1989 and 1994. This repair involved prosthetic annuloplasty in 31 patients (84%), valve resection in 31 (84%), chordal shortening or transposition in 19 (51%), pericardial patch in 16 (43%), and direct suture of leaflet perforation in 4 (11%). Associated procedures were primarily aortic valve repair or replacement in 11 (30%) and tricuspid repair in 2 (6%). Early complications included 1 operative death (3%; 95% CI, 0 to 15.5) and 1 reoperation for pericardial patch dehiscence. Recurrence of endocarditis was observed in 1 patient (3%; 95% CI, 0 to 16). The 10-year survival rate and freedom from mitral valve reoperation were 80% (95% CI, 66 to 94) and 91% (95% CI, 81 to 100), respectively. At 10 years, most patients (96%) were in good functional status (NYHA class I to II) with no or trivial mitral regurgitation (92%) on echocardiography. Conclusions—Mitral valve repair using Carpentier’s techniques in patients with active endocarditis offers very good long-term results with a low rate of recurrence or reoperation.

Videothoracoscopic lung biopsy in diffuse infiltrative lung diseases: a 5-year surgical experience

BACKGROUND To establish an accurate diagnosis of diffuse infiltrative lung disease, a surgical lung biopsy may be required. We report our experience with video-thoracoscopic lung biopsy over a period of 5 years. METHODS From March 1992 through December 1996, videothoracoscopic lung biopsy was performed in 64 patients (17 were women [26.5%]; age, 50.5+/-13 years) with a diagnosis of diffuse infiltrative lung disease of an unknown cause. All patients except one received general anesthesia. Single lung ventilation was used in 61 patients. All lung biopsies were obtained with an endoscopic stapler. RESULTS Single lung biopsies were performed in 39 patients (61%), two biopsies in 23 patients (36%), and three biopsies in 2 patients. Minithoracotomies were necessary in 10 patients (15.6%) owing to an iatrogenic pulmonary wound (1 patient), extensive pleural adhesions (6 patients), and a stiff lung (3 patients). Postoperative complications were rare and included five discrete pneumothoraces (7.8%), all resolving spontaneously, one prolonged air leak (1.6%), and one hemothorax requiring reoperation. Three preoperatively debilitated patients died (4.7%), 2 with progression of respiratory failure and 1 owing to septic shock. Average chest tube duration was 2.4+/-2 days and average hospital stay was 4.6+/-2.5 days. Lung biopsy contributed to the diagnosis in 59 patients (92%). CONCLUSIONS Videothoracoscopic lung biopsy using an endoscopic stapler is a safe and effective procedure in most cases and should be performed by trained thoracic surgeons.

Evidence of leaflet injury during percutaneous aortic valve deployment

It has been suggested that valved stent deployment during transcatheter aortic valve implantation may be responsible for traumatic injury to pericardial leaflets, especially with balloon expandable valved stents. However, such an injury has not been described nor reported so far. We here report the microscopic analysis of 4 Sapien-Edwards prostheses, 2 of which have been implanted in humans. There was no macroscopic evidence of traumatic injury to the pericardial leaflets of the percutaneous valves. However, pathological microscopic findings were observed in all of them. These mainly consisted of collagen fibers fragmentation and disruption. Areas of non- or mildly affected tissue were adjacent to areas of severely damaged tissue. The entire thickness of the leaflets might be involved. The severity of the lesions also differed among leaflets from a same prosthesis. Areas of plasmatic insudation were identified in one case. The disruption index was significantly higher in the Sapien group in comparison to the control group: 42.4% (14-63.5%) versus 17.5% (9.2-31%) (p < 0.001). Although of limited size sample, this study does prove that traumatic injury to leaflets occurs during percutaneous valves implantation. This should prompt physicians to wait for the long-term results of this new technology before extending the indications to low-risk patients.

Métaplasie de tissu aortique en tissu trachéal. Perspectives chirurgicales

Abstract Tracheal reconstruction after extensive resection remains an unsolved surgical problem. Numerous attempts have been made using tracheal grafts or prosthetic conduits with disappointing results. In this study, we propose a new alternative using an aortic autograft as tracheal substitute. In a first series of experiments, a half circumference of two rings was replaced with an autologous carotid artery patch. In a second series, a complete segment of trachea was replaced with an autologous aortic graft supported by an endoluminal tracheal stent. No dehiscence or stenosis was observed. Microscopic examinations at 3 and 6 months showed the replacement of the aortic tissue by tracheal tissue comprising neoformation of cartilage and mucociliary or non-keratinizing metaplastic polystratified squamous epithelium. Although these results need to be confirmed by a larger series of experiments, they showed that a vascular tissue placed in a different environment with a different function can be submitted to a metaplastic transformation which tends to restore a normal structure adapted to its new function. These remarkable findings offer new perspectives in tracheal reconstruction in human.

A new endovascular size reducer for large pulmonary outflow tract

Around 75% of patients with severe pulmonary insufficiency requiring valvular replacement are excluded from percutaneous pulmonary valve implantation (PPVI) due to a large ventricular outflow tract. To extend the indication of PPVI to these patients, a new size reducer has been designed. This 35-mm size reducer was successfully deployed inside the main pulmonary artery through a 21-Fr delivery catheter in six sheep. A 20-mm pericardial valved stent was subsequently deployed inside the size reducer to restore pulmonary valve continence. We successfully verified the efficiency of the delivery catheter by controlling the deployment precisely and reversibly. In all six cases, device positioning was satisfactory. There was no post-procedural residual stenosis in the right ventricular outflow tract in haemodynamic (9.5+/-3 mm Hg), echocardiographic and angiographic studies. After 8-12 weeks of follow-up, no prosthetic migration occurred. The transprosthetic systolic gradient remained low (4+/-2.5 mm Hg) during follow-up. There was one trivial persistent paraprosthetic leak. This study confirmed the feasibility and the effectiveness of this new size reducer to reduce the size of the pulmonary artery.

Percutaneous aortic valve replacement with the CoreValve prosthesis.

We read with interest the recent article of Grube et al. ([1][1]) dealing with percutaneous aortic valve implantation. They reported the experience from 3 centers using the second and third generations of the CoreValve prosthesis (CoreValve Inc., Irvine, California) in 86 consecutive patients. The

Traumatic leaflet injury during the use of percutaneous valves: a comparative study of balloon- and self-expandable valved stents

OBJECTIVES No comparison of balloon- or self-expandable valved stents (VSs) regarding tissue injury (if any) has been reported yet. The objective was to evaluate the occurrence and compare the severity of traumatic injury to leaflets from balloon- or self-expandable VSs. METHODS Twelve homemade VSs were used for this experiment. These three-leaflet bovine pericardial bioprostheses had either a stainless steel (Group A) or a nitinol stent (Group B). After a 30-min period of compression (external diameter of VS reduced to 7 mm), the prostheses were deployed by balloon inflation (Group A) or by unsheathing (Group B). After H&E staining, pericardial leaflets were subsequently analyzed qualitatively and quantitatively for microscopic lesions. Non-crimped pericardial leaflets were used as a control group (Group C). RESULTS All deployed VSs had microscopic lesions evocating traumatic injury to pericardial leaflets. Transverse fractures and longitudinal cleavages were the two main lesions encountered. Transverse fractures (no. per field) were significantly more frequent in the VS in comparison with the control group: 5 (range: 0-13), 4 (range: 0-9) and 0 (range: 0-1) in Groups A, B and C, respectively (P < 0.001). Cleavages (no. per field) were also more frequent with balloon-expandable VSs compared with self-expandable VSs [3 (range: 0-7) vs 1(range: 0-8); P = 0.03]. CONCLUSIONS Traumatic injury to the pericardial leaflets does occur during crimping and deployment of balloon- or self-expandable VSs. Injury may be more severe with the balloon-expandable VSs. The impact of such an injury on prosthesis durability requires a further investigation.

Exhaled carbon monoxide and inducible heme oxygenase expression in a rat model of postperfusion acute lung injury.

OBJECTIVE Expression of inducible heme oxygenase has been shown to be increased in various visceral inflammatory disorders, which may confer a protective role. The purpose of our study was to determine whether the expression of inducible heme oxygenase was up-regulated within lungs in a rat model of extracorporeal circulation. METHODS Wistar rats underwent either a partial femoro-femoral extracorporeal circulation in normothermia for 3 hours (n = 5) or a sham procedure (n = 5). Exhaled carbon monoxide concentration was monitored with an infrared analyzer. After the rats were killed, lungs were harvested for determination of heme oxygenase activity and inducible heme oxygenase expression (by Western blot and immunohistochemistry). Lung injury was also assessed by arterial blood gas analysis and microscopic study. RESULTS Extracorporeal circulation was responsible for a lung injury characterized by decreased arterial blood oxygen saturation and typical morphologic findings (marked alveolar neutrophil infiltration; interstitial edema). Exhaled carbon monoxide concentration remained stable throughout the experiment in all sham rats, whereas it increased after extracorporeal circulation (from 0.16 +/- 0.05 ppm at baseline to 0.7 +/- 0.2 ppm at end of experiment; P =.0001). Pulmonary heme oxygenase activity and inducible heme oxygenase content (assessed by Western blot) were increased within lungs of rats that underwent extracorporeal circulation. Immunohistochemistry revealed that the expression of inducible heme oxygenase was mainly localized to inflammatory cells. CONCLUSIONS Post-extracorporeal circulation acute lung injury in rats was associated with an increased expression of inducible heme oxygenase, the functional significance of which remains to be determined.