Long-term outcome after external tracheal stabilization due to congenital tracheal instability.

BACKGROUND: Long-segment tracheobronchial malacia may cause life-threatening dysfunction of the airway system at different levels. This study presents the long-term follow-up (1992 through 2008) of patients who received surgical treatment with external tracheal stabilization in our institution. METHODS: Eleven patients fulfilled the inclusion criteria. In surviving patients who presented for reexamination, pulmonary function testing, ergometry, and magnetic resonance imaging (MRI) were performed. RESULTS: All patients could be weaned from the ventilator and discharged. Patients were aged a median 11 months (range, 3 to 48 months) at operation for tracheal compression. Age at follow-up was 9.1 years (range, 0.5 to 16.3 years). Median follow-up was 7.3 years (range, 0.1 to 15.1 years). Postoperatively, 1 patient was lost to follow-up, and 4 died at 2.6 years (range, 0.5 to 6.6 years) of comorbidities. Pulmonary function testing showed a moderate residual airflow restriction, with maximal vital capacity at 75% of normal (range, 45% to 92%). Treadmill exercise testing demonstrated 70% to 89% of the expected normal values for age. Magnetic resonance imaging examination confirmed tracheal patency, but the lumen of the left main bronchus in 2 patients was 50% smaller than on the right. Diaphragmatic motion was normal in all patients. CONCLUSIONS: Children with congenital tracheal stenosis benefit from external tracheal stabilization. Survival in patients after external tracheal stabilization is significantly influenced by concomitant conditions.

The evolution of the pulmonary arterial sling syndrome, with particular reference to the need for reoperations because of untreated tracheal stenosis.

BACKGROUND: We present a group of infants and children with pulmonary arterial sling and tracheal stenosis. In some of the patients, the anomalously located pulmonary artery had previously been reimplanted, but without simultaneous repair of the trachea. METHODS: From 1992 to 2007, we reimplanted the left pulmonary artery in 13 children with a pulmonary arterial sling. Their median age was 8 months, with a range from 1 to 72 months. We also performed tracheal resection with end-to-end anastomosis, or complex tracheal reconstructions. In 5 patients, the reoperation was indicated because of persistent tracheal stenosis not treated initially at first correction of the arterial sling. All patients presented with stridor and respiratory distress. Cardiac catheterization, bronchoscopy and multidetecting computer tomography angiography were performed in all cases prior to the operation. All operations were performed under cardiopulmonary bypass. RESULTS: There was no operative or late mortality. The patients were extubated under bronchoscopic control. The mean period of intubation was 18 plus or minus 8 days, and the average follow-up was 8 plus or minus 4 years. The patients showed no signs of tracheal re-stenosis clinically or on bronchoscopy. The group of the patients under reoperations, however, required longer periods of intubation and hospitalization. CONCLUSION: Our experience demonstrates that, in patients with a pulmonary arterial sling, any associated tracheal stenosis should be explored at the initial operation, since decompression of the trachea by reimplanting the anomalously located pulmonary artery fails to provide relief. The funnel trachea, if present, undergoes progressive stenosis, and will require surgical repair. The use of cardiopulmonary bypass permitted extensive mobilization of the tracheobronchial tree, and allowed us to perform a tension-free anastomotic reconstruction of the trachea.

Overestimation of aortic valve replacement risk by EuroSCORE: implications for percutaneous valve replacement.

AIMS: The EuroSCORE has been proposed to identify patients at high risk for surgical aortic valve replacement (AVR) and estimate for them the risk-benefit of percutaneous valve replacement. The aim of our study was to investigate the validity of this proposal. METHODS AND RESULTS: From 1994 to March 2006, 1545 consecutive patients with aortic stenosis underwent isolated surgical AVR at the Department of Cardiac Surgery of Heidelberg. Both additive and logistic EuroSCOREs were calculated for each patient and summed for expected 30-day mortality. Expected and observed mortalities were compared, particularly with respect to 'high-risk' status and era of operation. Overall, 30-day mortality was low (34/1545, 2.2%) and substantially overestimated by both additive (6.1%) and logistic (9.3%) EuroSCOREs. Although both EuroSCOREs stratified patients monotonically with respect to mortality risk, high-risk patients had a 3.6% mortality (29/833), whereas additive and logistic EuroSCOREs predicted 8.3 and 14.8%. Indeed, none of the 71 patients with a EuroSCORE of 11-20 (extremely high risk) died. The more recent the era of operation, the more pronounced was the discrepancy between expected and observed mortalities. CONCLUSION: Although the EuroSCORE still successfully stratifies patients undergoing surgical AVR relative to 30-day mortality, it has become increasingly uncalibrated with absolute risk, resulting in overestimation of 30-day mortality. Inaccurately predicted mortality, especially in 'high-risk' patients, renders it unsuitable for assessing risk reduction of percutaneous valve replacement.

Aortic root motion remodeling after aortic valve replacement--implications for late aortic dissection.

Aortic root motion was previously identified as an additional risk factor for aortic dissection. This study analyzed if the magnitude of aortic root motion changed in patients after aortic valve replacement (AVR) and acute proximal aortic dissection. An institutional database (1984-2005) was used to measure the downward motion of the aortic root (perpendicular to the plane of the sinotubular junction) in contrast injections in 48 patients with aortic insufficiency (AI), aortic stenosis (AS) and proximal aortic dissection pre- and postoperatively, when available. Postoperative aortic root motion was significantly reduced after AVR for AI, while it was significantly increased after AVR for AS. By contrast, aortic root motion was unchanged when functional AI due to paravalvular leak was present post-AVR for AI. In patients with acute aortic dissection, both aortic root motion and aortic diameter were unchanged from pre-dissection. However, in patients who dissected again, aortic root motion was significantly smaller than pre-dissection, and the aortic diameter was significantly less than at first dissection. Removal of aortic stenosis was associated with increased aortic root motion, theoretically heightening the threat of dissection posed to the aortic wall by mechanical stress, although this was not confirmed by our study of dissection patients. Yet, mechanical principles command to include higher magnitude of aortic root motion during follow-up of patients after AVR as an additional risk factor for dissection.

Modified sliding tracheal plasty using the bridging bronchus for repair of long-segment tracheal stenosis.

A child with severe respiratory distress, previously operated on at age 4 months for pulmonary sling and atrial septal defect, underwent reoperation at age 4 years because of long-segment congenital tracheal stenosis complicated by an abnormal branching of the trachea-bridging bronchus. We review the anatomy of that rare pathomorphology and describe a slide tracheoplasty that uses the bridging bronchus for treatment of this complex anomaly.

Outcome after mechanical aortic valve replacement in children and young adults.

BACKGROUND: We asked whether aortic valve replacement using a mechanical prosthesis would allow normalization of left ventricular function and structure in children and young adults. METHODS: We performed a clinical follow-up examination in 30 patients with aortic valve replacement at 25 years of age or younger, including conventional and tissue Doppler echocardiography and magnetic resonance imaging. RESULTS: Aortic valve replacement was performed at the median age of 14.3 years (range, 7.6 to 24.3 years) using a mechanical prosthesis (St. Jude Medical; median diameter, 23 mm; range, 17 to 27 mm). Indications were severe aortic stenosis in 6 of 30 patients, aortic regurgitation in 20 of 30 patients, or a combination of aortic stenosis and regurgitation (4 of 30 patients). Aortic valve replacement was a reoperation in 12 of 30 patients who primarily underwent aortic valvotomy at a median of 7.1 years (range, 1.0 to 11.3 years). In-hospital mortality was 0%. Follow-up was a median of 6 years (range, 1.2 to 14.5 years). Twenty-nine of 30 patients were in New York Heart Association functional class I without thromboembolic complications, cerebrovascular accidents, or major bleeding on oral anticoagulation. Left ventricular dilatation before aortic valve replacement was present in 20 of 30 patients but normalized in all but 4 patients on follow-up. Most patients showed a normal end-diastolic volume on magnetic resonance imaging, and 23 of 26 patients showed a normal left ventricular ejection fraction (median, 0.53; range, 0.33 to 0.75). Peak systolic strain of the left ventricular myocardium was a median of -13.3% (range, -0.5% to -31%), and was normal in 28 of 30 patients. CONCLUSIONS: Aortic valve replacement in children and young adults offers a good treatment option and may lead to normalization of left ventricular size and function in most patients.

Replacement of valved right ventricular to pulmonary artery conduits: an observational study with focus on right ventricular geometry.

OBJECTIVE: Timing of the operation for exchange of right ventricular (RV) to pulmonary artery (PA) conduits is a matter of considerable debate. We aimed to study the course of right ventricular dimension in patients undergoing conduit exchange. PATIENTS AND METHODS: We retrospectively studied all patients who underwent implantation and or replacement of RV/PA conduits during the time period between 1990 and 2005. Clinical and echocardiographic data were recorded as obtained at follow-up visits. RESULTS: A total of 229 (144 boys and 85 girls) underwent surgery for implantation and or replacement of RV/PA conduits during the study period. Patients were assigned to three age groups including 37 infants, 125 children aged 1-10 years and 67 patients more than 10 years of age. 185 pulmonary (81%) and 44 aortic homografts (19%) were implanted. Fifty-eight of these 185 patients (25%) required exchange of conduits after a median time of 6.4 (8 months-12 years) (median (range)). The follow-up was 7.55 (0.1-17) years. The survival of the patients after homograft change was 98%. Freedom from failure for aortic and pulmonary homografts at an interval of 10 years for all patients was 38.5% for aortic and 56.2% for pulmonary homografts (P = 0.018; Mann-Whitney). Age at conduit exchange (coefficient: -4.917; P < 0.001) and right ventricular end-diastolic dimension (RVDD) before conduit exchange (coefficient: 8.255; P < 0.001) were related to RVDD as measured by M-mode echocardiography at follow-up ("best subset" regression analysis; R squared = 0.746). RVDD decreased in 48/58 patients, remained unchanged in 8/58 and increased in 2/59 patients at follow-up. An increased RVDD was positively correlated to the duration of artificial ventilation after the operation for conduit exchange (R = 0.56; P < 0.001). CONCLUSIONS: Reoperation for exchange of degenerated conduits should be performed early to prevent the development of irreversible structural myocardial changes and persistence of right ventricular dilatation.

Atrasentan treatment of pulmonary vascular disease in piglets with increased pulmonary blood flow.

We studied the effect of chronic endothelin A receptor blockade by atrasentan on the pulmonary endothelin-1 system and vascular endothelial growth factor (VEGF) expression in piglets with high pulmonary blood flow. Twenty-five 4-week-old piglets with high pulmonary blood flow were randomized to three groups: sham operated (n = 8), placebo (water) (n = 7), or treatment with atrasentan (2 mg/kg per day) (n = 10). After 3 months, mean pulmonary arterial pressure (PAP) was higher in the placebo group than in the sham group [18 +/- 2 mm Hg versus 14 +/- 1 mm Hg; P < 0.05 (ANOVA)]. Atrasentan treatment was associated with lower cardiac output, PAP (14 +/- 1 mm Hg), and medial wall thickness of pulmonary arteries (diameter: 50-150 microM) compared with placebo [13.6 +/- 3.0% versus 18.1 +/- 4.2%; P < 0.05 (ANOVA)]. Quantitative real-time polymerase chain reaction for endothelin-1, endothelin B receptor, and endothelin-converting enzyme-1 mRNA in lung tissue did not differ. However, immunostaining as well as mRNA for VEGF were lower in atrasentan-treated animals (relative gene expression: atrasentan versus placebo: 0.8 +/- 0.3 versus 1.5 +/- 0.3; P = 0.009). Atrasentan treatment effectively reduces medial hypertrophy in piglets with chronic pulmonary hyperperfusion. Chronic endothelin A receptor blockade by atrasentan may interfere with the expression of VEGF.

Pulmonary vascular changes in piglets with increased pulmonary blood flow and pressure.

In this model of pulmonary vascular disease, high pulmonary blood flow was created by an anastomosis between the left subclavian artery and the main pulmonary artery [Blalock-Taussig (BT) shunt] in 4-week-old piglets (n = 6). Additional ligation of the left pulmonary artery (LPA) was used to increase pulmonary artery pressure (n = 6). Seven piglets were sham-operated. After 3 months, mean pulmonary artery pressure was higher in animals with BT shunt and LPA ligation (22 +/- 5; mean+/-SD) compared to sham-operated animals (15 +/- 2). In addition, thickening of the medial coat (20.1 +/- 2.8% versus 13.6 +/- 3.1% wall thickness) and increased immunostaining for vascular endothelial growth factor A (VEGF-A) were observed. Relative gene expression for endothelin-converting enzyme-1 (ECE-1) mRNA was 1.8 times higher, and VEGF-A mRNA was 2.5 times higher in pigs with BT shunt and LPA ligation compared with sham-operated animals. VEGF receptor-1 and VEGF receptor-2 mRNA was lower in shunted animals and in animals with additional ligation of LPA. Upregulation of ECE-1 and VEGF-A, as well as changes in VEGFR expression in the pulmonary hypertensive lung, may contribute to pulmonary vascular changes.

Poly(ADP-ribose) polymerase inhibition combined with irradiation: a dual treatment concept to prevent neointimal hyperplasia after endarterectomy.

PURPOSE: In a rat model of endarterectomy we investigated the potential role of the peroxynitrite-poly(ADP-ribose) polymerase (PARP) pathway in neointima formation and the effects of irradiation, pharmacologic inhibition of PARP, or combined pharmacologic inhibition of PARP and irradiation on vascular remodeling. METHODS AND MATERIALS: Carotid endarterectomy was performed by incision of the left carotid artery with removal of intima in Sprague-Dawley rats. Six groups were studied: sham-operated rats (n = 10), control endarterectomized rats (n = 10), or endarterectomized rats irradiated with 15 Gy (n = 10), or treated with PARP inhibitor, INO-1001 (5 mg/kg/day) (n = 10), or with combined treatment with INO-1001 and irradiation with 5 Gy (n = 10) or with 15 Gy (n = 10). After 21 days, neointima formation and vascular remodeling were assessed. RESULTS: Neointima formation after endarterectomy was inhibited by postoperative irradiation with 15 Gy and was attenuated by PARP inhibition. However, in parallel to inhibition of neointimal hyperplasia, activation of the peroxynitrite-PARP pathway in the outer vessel wall layers was triggered by postoperative irradiation. Combined pharmacologic PARP inhibition and irradiation with 15 Gy significantly reduced both neointimal hyperplasia and activation of the peroxynitrite-PARP pathway in the outer vessel wall layers. Combination of PARP inhibition and irradiation with 5 Gy was less effective than both PARP inhibition or irradiation with 15 Gy alone. CONCLUSIONS: We conclude, that combined PARP inhibition and irradiation with 15 Gy may be a new dual strategy for prevention of restenosis after surgical vessel reconstruction: combining the strong antiproliferative effect of irradiation and ameliorating irradiation-induced side effects caused by excessive PARP activation.

Adaptation of the right ventricle to an increased afterload in the chronically volume overloaded heart.

BACKGROUND: Increased right ventricular afterload is a common problem after correction of various heart diseases with chronic volume overload. We determined the effects of an acute increase of right ventricular afterload in normal and chronically volume overloaded hearts. METHODS: In 6 dogs, volume overload was induced by chronic arteriovenous shunts for 3 months. Six sham-operated animals served as controls. After closing the shunts, right ventricular systolic and end-diastolic pressure as well as end-diastolic volume were measured by conductance catheter. In addition, pressure-volume loops were recorded. Myocardial contractility was described by the slope of the end-systolic pressure-volume relationship. Afterload was increased to right ventricular systolic pressure to 35 mm Hg and to 50 mm Hg by pulmonary banding. RESULTS: Chronic volume overload resulted in a significant increase of right ventricular systolic pressure (34 +/- 2 versus 25 +/- 2 mm Hg, p < 0.05), end-diastolic pressure (10.4 +/- 1.7 versus 6.8 +/- 0.4 mm Hg, p < 0.05), and end-diastolic volume (39 +/- 2 versus 33 +/- 3 mL, p < 0.05). Baseline contractility (1.47 +/- 0.24 versus 1.53 +/- 0.32 mm Hg/mL) did not differ. While afterload increase to 35 and 50 mm Hg led to stepwise increase in contractility (2.73 +/- 0.30 mm Hg/mL and 4.15 +/- 0.30 mm Hg/mL, p < 0.05 versus baseline, respectively) at unchanged end-diastolic pressure and volume in controls, it showed only a slight increase (2.11 +/- 0.38 mm Hg/mL and 2.99 +/- 0.29 mm Hg/mL, p < 0.05 versus sham) with concomitant increase in end-diastolic pressure (12.4 +/- 2.2 mm Hg/mL and 16.3 +/- 1.9 mm Hg, p < 0.05) and volume (42 +/- 4 mL and 48 +/- 8 mL, p < 0.05) in the chronically volume overloaded group. CONCLUSIONS: Chronic volume overload per se does not impair right ventricular contractility. However, the inotropic adaptation (homeometric autoregulation) to an increased afterload is limited, which is partly compensated by the Frank-Starling mechanism (heterometric autoregulation).

Poly(ADP-ribose) polymerase inhibition reverses vascular dysfunction after gamma-irradiation.

PURPOSE: The generation of reactive oxygen species during gamma-irradiation may induce DNA damage, leading to activation of the nuclear enzyme poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) culminating in endothelial dysfunction. In the present study, we assessed the effect of PARP inhibition on changes in vascular function after acute and short-term irradiation. METHODS AND MATERIALS: In the acute experiments, aortic rings were exposed to 20 Gy of gamma-irradiation. The aortae were harvested after 1 or 7 days. Two additional groups received the ultrapotent PARP inhibitor, INO-1001, for 1 or 7 days after irradiation. The aortic rings were precontracted by phenylephrine and relaxation to acetylcholine and sodium nitroprusside were studied. RESULTS: The vasoconstrictor response to phenylephrine was significantly lower both acutely and 1 and 7 days after irradiation. Vasorelaxation to acetylcholine and sodium nitroprusside was not impaired acutely after irradiation. One and seven days after irradiation, vasorelaxation to acetylcholine and sodium nitroprusside was significantly enhanced. Treatment with INO-1001 reversed vascular dysfunction after irradiation. CONCLUSION: Vascular dysfunction was observed 1 and 7 days after irradiation, as evidenced by reduced vasoconstriction, coupled with endothelium-dependent and -independent hyperrelaxation. PARP inhibition restored vascular function and may, therefore, be suitable to reverse vascular dysfunction after irradiation.

Morphometric changes of the right ventricle in the first two weeks after clinical heart transplantation: analysis of myocardial biopsies from patients with complicated versus uncomplicated course.

OBJECTIVE: The early phase following heart transplantation (HTx) is characterized by the development of right ventricular myocardial fibrosis (MF) and cardiomyocyte hypertrophy (CH). The question is if there are differences in development of MF and CH between patients with complicated versus patients with uncomplicated postoperative course. METHODS: Endomyocardial biopsies were taken from 58 donor hearts before implantation and one and two weeks after HTx. According to the clinical course in the first year after HTx and the rejection grading (ISHLT), four groups were classified: (a) uneventful course, (b) transplant failure, (c) infections, and (d) rejection episodes > or = 1R. The volume densities of various tissue components and cardiomyocyte diameters were measured by stereological and morphometrical methods. RESULTS: From implantation to the first two weeks, most groups showed a significant increase of endomysial and perimysial connective tissues. There was a significant CH recognizable, especially in the rejection group. However, nucleus surface, a hypertrophy parameter, showed no significant change during follow-up. There were no statistically significant differences in volume densities of interstitial space, capillaries, nuclei and cardiomyocytes between the collectives and points in time. Sarcomere length as marker of contraction status of cardiomyocytes remained at the same level and showed no significant differences. Demographic data showed no significant differences and will be presented. CONCLUSIONS: Patients with complicated and uncomplicated courses show different degrees of histopathological changes after HTx. The extent of hypertrophy differs especially between the collectives. Measurement of endomysial connective tissue points to later postoperative course in the recipient. These findings may reflect a pattern of remodeling specific to the transplanted heart.

Late results after extended pulmonary artery reconstruction in the arterial switch operation.

BACKGROUND: Pulmonary artery stenosis remains the most frequent late complication and cause of reintervention after the arterial switch operation for transposition of the great arteries. We investigated the influence of an extended pericardial patch augmentation of the neopulmonary root and pulmonary artery on late pulmonary artery stenosis development. METHODS: Augmentation of the neopulmonary root and pulmonary artery was achieved by reconstructing the posterior wall using a large glutaraldehyde-treated autologous pericardial patch. Reviewed were regular follow-up echocardiograms from 58 out of 87 patients undergoing the arterial switch operation who presented a follow-up period of at least 5 years. An actual follow-up echocardiographic evaluation focusing on the maximal instantaneous transpulmonary continuous-wave (cw)-Doppler gradient was performed, followed by cardiac catheterization when indicated (peak cw-Doppler gradient > 40 mm Hg). RESULTS: Follow-up was 8.9 [5 to 15] years. There was no reintervention due to residual pulmonary artery stenosis. Actual Doppler examination revealed a transpulmonary peak gradient of 19.5 [0 to 56] mm Hg, compared with 20 [0 to 60] mm Hg at discharge. Forty-three patients (74.1%) had no or only trivial pulmonary artery stenosis (pressure gradient < 25 mm Hg), 14 patients (24.2%) had mild stenosis (25 to 49 mm Hg), and 1 patient (1.7%) had moderate stenosis (50 to 79 mm Hg). CONCLUSIONS: Compared with the majority of literature data, we could demonstrate a low incidence of late pulmonary artery stenosis after the arterial switch operation by employing an extended pericardial patch reconstruction technique with augmentation of the neopulmonary root and pulmonary artery.