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Biomedical subjects

B J Messmer

Publications and source records attributed to B J Messmer.

At least 55 records · Page 3Linked to original sources
PubMed1999

Optimized pulse durations minimize the effect of polarity reversal on defibrillation efficacy with biphasic shocks.

There are conflicting results on the effect of polarity change on the defibrillation efficacy of biphasic shocks possibly caused by different shock durations. The goal of the present study was to investigate the influence of polarity reversal on defibrillation efficacy for different biphasic shock durations in a porcine animal model. In eight anesthesized pigs using a transvenous/submuscular lead system DFTs for 4 phase 1 durations were determined: 8.1 ms, 6 ms, 3.8 ms and 1.7 ms. The phase 1/phase 2 ratio was constant at 60%/40%. For cathodal shocks, the defibrillation coil in the right ventricular apex was the cathode during phase 1 and for anodal shocks it was the anode. For both polarities, the strength-duration curve revealed a DFT minimum at 3.8 ms (cathodal shocks: 21.3 +/- 6.4 J, P < 0.001; anodal shocks: 21.9 +/- 8 J, P = 0.05). For anodal shocks and phase 1 durations of 1.7, 3.8, and 6 ms there was no significant difference of the stored energy at the DFT compared to cathodal shocks. In contrast, significantly lower DFTs were observed for anodal shocks with a phase 1 duration of 8.1 ms (28.8 +/- 6.4 J compared to 33.1 +/- 5.9 J for cathodal shocks, P = 0.006). The effect of lower defibrillation energy requirements with polarity reversal depends on the total biphasic shock duration; for the pulse duration with the lowest DFT, polarity reversal does not increase defibrillation efficacy of biphasic shocks.

Animals↗
PubMed1998

Influence of phase duration of biphasic waveforms on defibrillation energy requirements with a 70-microF capacitance.

BACKGROUND: Phase duration of biphasic shocks may be an important determinant of defibrillation success. The purpose of this study was to investigate the effect of changing phase duration of biphasic pulses delivered by 70-microF capacitors on defibrillation energy requirements. This may be clinically relevant for the optimization of implantable cardioverter-defibrillator design and programming. METHODS AND RESULTS: Defibrillation thresholds (DFTs) were determined for 13 waveforms in 13 pigs by application of a 70-microF capacitance and a transvenous/submuscular lead system. In part I, phase-1 duration varied, preserving a phase-1/phase-2 duration ratio of 60%/40%. The phase-1 durations were 1, 2, 3, 4, 5, and 6 ms. The DFT was lowest (22.9+/-7 J) for phase 1=3 ms compared with phase 1=1 ms (36.4+/-7.5 J), 2 ms (25+/-6.5 J), 4 ms (25+/-7.6 J), 5 ms (30.7+/-7.3 J), or 6 ms (32.9+/-8.1 J) (P<.001). In part II, phase-1 duration was 3 ms but phase-2 duration varied: 0.7, 1.3, 2, 2.7, 3.3, 4, and 6 ms. Significant DFT minima were found at phase 2=2 ms (22.5+/-4.2 J) and phase 2=4 ms (22.5+/-4.2 J) compared with phase 2=0.7 ms (31.7+/-9.3 J), phase 2=3.3 ms (26.7+/-6.1 J), or phase 2=6 ms (28.3+/-6.8 J) (P<.05). CONCLUSIONS: The strength-duration curve of biphasic defibrillation shocks demonstrates a single optimum for phase-1 duration. In contrast, two optima with minimal energy requirements were found for phase-2 duration. Optimization of both phases of low-capacitance biphasic shocks may reduce energy requirements for defibrillation.

Animals↗
PubMed1998

Growth of pulmonary artery after arterial switch operation for simple transposition of the great arteries.

UNLABELLED: This retrospective study attempts to assess the size and growth pattern of the pulmonary artery about 1 year after neonatal arterial switch operation for simple transposition of the great arteries. Sixty-seven patients underwent cardiac catheterization, including catheterization of the right and left pulmonary arteries, and right ventricular angiography an average of 13.9 months after arterial switch operation. In 34 of these patients pre-operative right ventricular angiocardiograms were available. The diameter of the main pulmonary artery and that of its proximal right and left branches were measured. The values were compared to those of normal children matched for body surface area, taken from the literature and, for the branch values, related to the degree of branch stenosis and to the corresponding values, measured on pre-operative angiocardiograms. The cross-section of the main pulmonary artery after arterial switch operation with Lecompte manoeuvre becomes oval. The branches of the pulmonary artery are sometimes underdeveloped and this finding is related to branch stenosis. The ratio of the branch gradients is inversely proportional to the growth ratio of both branches while the pre- and postoperative Nakata indices are identical. CONCLUSION: The Lecompte manoeuvre induces a flattening of the main pulmonary artery with concomitant reduction of its cross-sectional area. There is also frequently trivial or rarely moderate branch pulmonary stenosis which is accompanied by growth retardation of the concerned branch.

Angiocardiography↗
PubMed1998

Cantrell's syndrome: a challenge to the surgeon.

We present a case of partial Cantrell's syndrome with ventricular septal defect, left ventricular diverticulum, dextrorotation of the heart, an anterior diaphragmatic defect, and a midline supraumbilical abdominal wall defect with omphalocele. At the age of 20 months, the patient underwent a successful cardiac surgical procedure. To detect risk factors and to define therapeutic strategies, we analyzed the spectrum and the frequency of malformations described in 153 patients with Cantrell's syndrome. Despite modern surgical standards, Cantrell's syndrome represents a challenge to the surgeon because of the wide spectrum of anomalies, the severity of the abdominal and cardiac malformations, and the high mortality.

Abdominal Muscles↗
PubMed1998

Anomalous origin of the right coronary artery: preoperative and postoperative hemodynamics.

Anomalous origin of the right coronary artery from the main pulmonary artery is a rare congenital cardiac malformation. Most patients remain asymptomatic. However, there are cases of sudden cardiac death described in the literature, indicating a potentially malign course of the disease. To establish a double-ostium coronary system, correction of the aberrant vessel is recommended. Despite surgical reconstitution of normal coronary anatomy, the postoperative clinical presentation of some patients does not improve substantially, raising the question of the functional outcome of reinserted coronary vessels. This report of a patient with anomalous origin of the right coronary artery from the pulmonary trunk, in whom a complete hemodynamic assessment including intracoronary Doppler flow measurements was performed before and after reimplantation, very strongly supports the concept of an anatomically corrective operation.

Coronary Circulation↗
PubMed1998

Prolonged myocardial hibernation exacerbates cardiomyocyte degeneration and impairs recovery of function after revascularization.

OBJECTIVES: We sought to define the effects of time on contractile function, morphology and functional recovery after coronary revascularization in patients with dysfunctional but viable (hibernating) myocardium. BACKGROUND: Functional recovery after coronary artery bypass graft surgery in patients with chronic myocardial hibernation is incomplete or delayed. The proposed cause is a progressive temporal degeneration of cardiomyocytes. METHODS: In 32 patients with multivessel coronary disease, regional wall motion analysis was performed in hypoperfused but metabolically active areas before and 6 months after bypass surgery. During bypass surgery, transmural biopsy samples were obtained from the center of the hypokinetic zone for light and electron microscopic analyses. The proposed duration of myocardial hibernation was retrospectively assessed. RESULTS: Patients with a subacute hibernating condition (<50 days) demonstrated a higher preoperative ejection fraction (EF, 50+/-8%), and a better preserved wall motion (WM) in the supraapical wall (-1.4+/-0.4) than did patients with intermediate-term (>50 days, EF 37+/-9%, p < 0.05; WM -2.4+/-1.5, p = 0.08) or chronic (>6 months, EF 40+/-14%, WM -2.7+/-0.9, p < 0.005) ischemia. Structural degeneration correlated with the duration of ischemia (r = 0.56, p < 0.05). Postoperative recovery of function was enhanced in patients with a short history of hibernation compared with patients with an intermediate-term or chronic condition (EF 60+/-10% vs. 40+/-10%, p < 0.001, and vs. 47+/-14%, p < 0.05). CONCLUSIONS: Hibernating myocardium exhibits time-dependent deterioration due to progressive structural degeneration with enhanced fibrosis. Early revascularization should be attempted to salvage the jeopardized tissue and improve postoperative outcome.

Aged↗
PubMed1998

Quantitative assessment of the operative results after extended myectomy and surgical reconstruction of the subvalvular mitral apparatus in hypertrophic obstructive cardiomyopathy using dynamic three-dimensional transesophageal echocardiography.

OBJECTIVES: The aim of this study was to examine the value of dynamic three-dimensional (3D) transesophageal echocardiography (TEE) for the postoperative evaluation after extended myectomy and surgical reconstruction of the subvalvular mitral valve apparatus in patients with hypertrophic obstructive cardiomyopathy (HOCM). BACKGROUND: Two-dimensional imaging techniques such as echocardiography, computed tomography and magnetic resonance imaging have not been able to precisely quantify the effects of surgical therapy on the morphology of the left ventricular outflow tract (LVOT). METHODS: Multiplane TEE with 3D reconstruction was performed in 11 patients before and after the operation and in 16 normal control subjects for comparison. The preoperative maximal systolic pressure gradient in the LVOT was 69 +/- 59 mm Hg. The following variables were measured within the dynamic 3D data set: depth, width, length and cross-sectional area (CSA) gain caused by the myectomy trough, minimal CSA of the LVOT at each time point and its cyclic changes and maximal mitral leaflet deviation during systole. RESULTS: Functional class improved from 3.0 +/- 0.2 before the operation to 1.5 +/- 0.6 after it. The maximal systolic pressure gradient in the outflow tract decreased to 26 +/- 21 mm Hg postoperatively (p < 0.001). Minimal CSA of the outflow tract increased from 1.1 +/- 1.2 to 3.8 +/- 1.9 cm2 postoperatively (p < 0.001), similar to the value of the control group (4.2 +/- 1.5 cm2, p = NS). The area gain due to the myectomy trough was 1.3 +/- 1.0 cm2, corresponding to 48 +/- 12% of the total operative area difference. Maximal systolic depth of the myectomy was 7 +/- 2 mm, maximal width was 20 +/- 8 mm and length was 28 +/- 7 mm. Maximal deviation of the mitral leaflets fell from 15 +/- 7 to 6 +/- 7 mm postoperatively (p < 0.01). In five patients mass measurements of the intracavitary portion of the papillary muscle (PM) revealed an increase from 7.3 +/- 1.0 to 12.1 +/- 2.5 g due to surgical mobilization of PMs (p < 0.01). CONCLUSIONS: 3D TEE quantifies the differences in outflow tract morphology before and after surgery for HOCM. This technique may have an impact on the planning of operative interventions and allow for the evaluation of its results.

Adult↗
PubMed1998

Pulmonary artery stenosis after systemic-to-pulmonary shunt operations.

OBJECTIVE: Systemic-to-pulmonary shunt operations are still required for palliation of certain congenital heart defects. The aim of this study was to analyze the incidence and etiology of the development of pulmonary artery stenosis after these procedures. METHODS AND RESULTS: Pre- and post-operative angiograms of 59 patients who underwent 54 peripheral and 12 central shunt operations were analyzed retrospectively. Patients without prior cardiovascular interventions (group I, n = 47) were differentiated from patients with prior interventions (group II, n = 12). In group I, all peripheral shunts were inserted contralaterally to the ductus arteriosus. Follow-up for all patients was 1.8 years (4 days-7.8 years). Pulmonary artery stenosis was diagnosed in 12/59 patients (20.3%, group I 12/47; group II 0) after a time interval of 4 days up to 5.3 years and only after Blalock-Taussig shunts (one classical, 11 modified) (12/40 = 30%). The stenoses were located ipsilaterally to the shunt in 7/12 and contralaterally in 5/12. Statistical analysis did not show any impact of age, weight, sex, shunt type or size, pulmonary artery diameters, Nakata and McGoon indices and prior interventions on the development of pulmonary artery stenosis. However, a patent ductus arteriosus and administration of Prostaglandin E1 had a significant impact on the development of pulmonary artery stenosis on the side of the ductus arteriosus. CONCLUSION: Pulmonary artery stenosis is not a rare event after systemic-to-pulmonary shunt operations. A patent ductus arteriosus with or without administration of Prostaglandin E1 is related to pulmonary artery stenosis on the side of the ductus arteriosus. Pulmonary artery stenosis on the side of a peripheral shunt may be caused by inappropriate surgical technique, increased intimal proliferation, or pulmonary artery kinking. Treatment depends on severity of cyanosis and on further surgical plans.

Adolescent↗
PubMed1998

Influence of polarity reversal on defibrillation success with biphasic shocks and a transvenous/subcutaneous defibrillator system in a porcine animal model.

Clinical studies show that polarity reversal affects defibrillation success in transvenous monophasic defibrillators. Current devices use biphasic shocks for defibrillation. We investigated in a porcine animal model whether polarity reversal influences defibrillation success with biphasic shocks. In nine anesthetized, ventilated pigs, the defibrillation efficacy of biphasic shocks (14.3 ms and 10.8 ms pulse duration) with "initial polarity" (IP, distal electrode = cathode) and "reversed polarity" (RP, distal electrode = anode) delivered via a transvenous/subcutaneous lead system was compared. Voltage and current of each defibrillating pulse were recorded on an oscilloscope and impedance calculated as voltage divided by current. Cumulative defibrillation success was significantly higher for RP than for IP for both pulse durations (55% vs 44%, P = 0.019) for 14.3 ms (57% vs 45%, P < 0.05) and insignificantly higher for 10.8 ms (52% vs 42%, P = ns). Impedance was significantly lower with RP at the trailing edge of pulse 1 (IP: 44 +/- 8.4 vs RP: 37 +/- 9.3 with 14.3 ms, P < 0.001 and IP: 44 +/- 6.2 vs RP: 41 +/- 7.6 omega with 10.8 ms, P < 0.001) and the leading edge of pulse 2 (IP: 37 +/- 5 vs RP: 35 +/- 4.2 omega with 14.3 ms, P = 0.05 and IP: 37.5 +/- 3.7 vs RP: 36 +/- 5 omega with 10.8 ms, P = 0.02). In conclusion, in this animal model, internal defibrillation using the distal coil as anode results in higher defibrillation efficacy than using the distal coil as cathode. Calculated impedances show different courses throughout the shock pulses suggesting differences in current flow during the shock.

Animals↗
PubMed1997

Quantitative analysis of the morphology of secundum-type atrial septal defects and their dynamic change using transesophageal three-dimensional echocardiography.

BACKGROUND: A noninvasive method for the determination of size and spatial relationships of atrial septal defects to adjacent cardiac structures, which would be advantageous to those contemplating device closure, is described. The aim of the study was to examine the value of transesophageal three-dimensional echocardiography for this purpose. METHODS AND RESULTS: Three-dimensional reconstruction of transesophageal two-dimensional echocardiography was performed in 17 patients. Left-to-right shunt (by oximetry in 16 of 17 patients) was 2.4 to 16.2 L/min, and the Qp/QS ratio was 1.4 to 4.7. The defect area of the atrial septal defect was measured throughout the whole cardiac cycle each 40 ms from the three-dimensional data set. Results were compared with shunt parameters by oximetry and with intraoperative measurements. Distances between atrial septal defect and mitral and tricuspid annulus and the orifices of the caval and pulmonary veins were also measured. The atrial septal defect area ranged from 0.2 to 2.4 cm2 (diastole) to 0.5 to 5.6 cm2 (systole). The maximal area at end-systole was 108% of the area at beginning of systole, and the minimal area at end-diastole was 43%. The defect area correlated significantly with the Qp/QS ratio (r=.70), and the maximal atrial septal defect diameters as measured by using three-dimensional echocardiography correlated well with intraoperative measurements (r=.87). Distances to mitral and tricuspid annulus and to the superior caval vein were determined in all patients. Distances to orifice of the inferior caval vein were measured in 12 patients, and orifices of right pulmonary veins were visible in 5 patients. CONCLUSIONS: Transesophageal three-dimensional echocardiography of atrial septal defects allows the determination of the instantaneous defect area and its dynamic changes and thus provides valuable information about the distances to adjacent cardiac structures. This may have clinical implications for the selection of patients suitable for interventional closure and for the assessment of procedural success.

Adult↗
PubMed1997

Angiographic study of aorta, coronary arteries, and left ventricular performance after neonatal arterial switch operation for simple transposition of the great arteries.

This retrospective study attempts to assess the growth pattern of the aorta and the coronary arteries and the left ventricular function approximately 1 year after neonatal arterial switch operation for simple transposition of the great arteries. Seventy-one patients underwent cardiac catheterization and cineangiocardiography an average of 13.5 months after the operation. The diameters of aortic annulus, aorta at different sites, and coronary arteries were compared with normal ranges taken from the literature. Left ventricular systolic performance was also evaluated. Observations included the following: Neoaortic annulus and root were larger than normal, trivial or mild neoaortic regurgitation was frequently observed, and the development of aortic anastomosis was normal. One patient had unexpected coronary occlusion, one had a coronary artery fistula, and two had a hypoplastic left anterior descending coronary artery. Except in one child who underwent an internal mammary bypass graft immediately after anatomic correction, the global left ventricular performance was normal. Six patients had regional wall motion abnormalities. Our midterm results are encouraging, but potential late complications remain concerns that must continue to be evaluated in long-term follow-up studies.

Aorta↗
PubMed1997

Cognitive and motor development in preschool and school-aged children after neonatal arterial switch operation.

OBJECTIVE: The developmental status of children beyond 3 years of age after the neonatal arterial switch operation has not yet been systematically evaluated and is the topic of the present work. METHODS: Seventy-seven unselected children operated on as neonates with combined deep hypothermic circulatory arrest and low-flow cardiopulmonary bypass were examined at an age of 3.2 to 9.4 years (5.4 +/- 1.6 years, mean +/- standard deviation). Clinical neurologic status, standard scores of intelligence, acquired abilities and vocabulary, and standardized tests on gross motor and fine motor functions were carried out, and the results were related to preoperative, perioperative, and postoperative status and management. RESULTS: Neurologic impairment was more frequent (9.1%) than in the normal population. Intelligence was not different in these patients compared with normal children (p = 0.11), but motor function, vocabulary, and acquired abilities were poorer. Reduced intelligence was found in 9.1%, fine motor dysfunction in 22.1%, and gross motor dysfunction in 23.4% of the children. Intelligence was weakly but significantly inversely related to the duration of bypass (Spearman correlation coefficient -0.25, p = 0.03) and tended to be inversely related to the duration of circulatory arrest (-0.21, p = 0.07), but not to core cooling time on bypass or degree of hypothermia. Gross motor function, vocabulary, and acquired abilities were not significantly related to any of the perioperative parameters considered. No correlation was found between the test results and the variables perinatal asphyxia, perioperative and postoperative cardiocirculatory insufficiency, resuscitation events, and plexal or intraventricular cerebral hemorrhage. CONCLUSIONS: The neonatal arterial switch operation with combined circulatory arrest and low-flow bypass in our experience is associated with neurologic as well as fine and gross motor impairment but appears to be well tolerated concerning cognitive functions as based on formal intelligence testing.

Cardiopulmonary Bypass↗
PubMed1997

Trial of pulmonary artery banding: a diagnostic criterion for 'one-stage' arterial switch in simple transposition of the great arteries beyond the neonatal period.

OBJECTIVE: Arterial switch operation (ASO) is the procedure of choice for the repair of simple d-transposition of the great arteries (TGA) during the neonatal period. Beyond this time such correction is performed in two stages. The first step incorporates banding of the pulmonary artery with or without a Blalock-Taussig shunt to train the left ventricle (LV). The second step consists of the ASO. To find out whether candidates for a two-stage procedure would tolerate a one-stage correction, a trial of pulmonary artery banding was performed. MATERIAL AND METHODS: Between February 1986 and December 1995, 224 patients less than 3 months of age with TGA, intact ventricular septum or a small restrictive ventricular septal defect, had an ASO. Seven patients were 4 weeks of age or older (28-70 days). Two of these had a pulmonary artery to systemic pressure ratio higher than 0.6 and underwent primary ASO without complications. The remaining five patients had low left ventricular pressure with a pulmonary to systemic pressure ratio of 0.2-0.5; echocardiography showed a banana-shaped LV with left ventricular wall thickness as low as 3 mm. They underwent a trial of pulmonary artery banding to systemic pressure for 15-30 min. As this increase in workload was tolerated well with an anticipated decrease of oxygen saturation but without hemodynamic disturbances anticipated, the ASO was performed immediately. RESULTS: Postoperative course was uneventful in all five patients, although catecholamine dependence was prolonged and three patients received enoximone. There were no severe complications. Echocardiography showed an increase in posterior wall thickness from 3 to 6 mm after 19 days in one infant. CONCLUSION: Some of the children, assigned for a 'two-stage' ASO may tolerate a primary anatomic repair up to an age of at least three months. This subgroup can be selected by a trial of pulmonary artery banding.

Echocardiography↗
PubMed1997

Cardiological and general health status in preschool- and school-age children after neonatal arterial switch operation.

OBJECTIVE: Cardiological and general health status 3-9 years after neonatal arterial switch operation for transposition of the great arteries should be evaluated by non-invasive methods. METHODS: A total of 77 unselected children with intact ventricular septum (75.3%) or ventricular septal defect (24.7%) without or with aortic isthmic stenosis (5.2%) were prospectively examined 3.2-9.4 years (5.4 +/- 1.6) after neonatal switch. Clinical pediatric and cardiological examination, standard and 24 h Holter electrocardiogram, M-mode, 2D-, Doppler and colour Doppler echocardiography were performed. Outcome data were compared to published normals. RESULTS: Reoperation rate was 2.6%, 96.1% were without limitation of physical activity and 98.7% without medication. Compared to normals, growth was adequate, weight and head circumference were slightly reduced. After median sternotomy, 23.4% had abnormal thoracic configuration (16.9% asymmetry, 6.5% funnel chest). ECG and Holter: 93.5% were in sinus, 6.5% in ectopic atrial or junctional rhythm. Incidence of complete right bundle branch block was 15.8% in patients with ventricular septal defect and 5.2% in those without. Ischemic ST-T changes during exercise due to coronary artery occlusion and evidence of old myocardial infarction were found in 1 patient (1.3%) each. Occasional atrial ectopy was found in 27.4%, ventricular ectopy in 15.3%: occasional in 12.5% and frequent (> 30/h) in 2.8% presenting bigemini, couplets and short runs of ventricular tachycardia at rest and during exercise. Echocardiography: Left ventricular function was normal in all. Endsystolic diameter of neoaortic valve annulus was beyond 90% confidence interval for controls in 79.2%, neoaortic root diameter in 100%. Mild aortic insufficiency was seen in 10.4%. No correlation was found between aortic insufficiency and aortic dilatation. Neoaortic stenosis was not seen, mild residual coarctation after end-to-end-anastomosis was found in 2.6%, native coarctation corrected later on in 1.3%. Supravalvular pulmonary stenosis was seen in 29.9% (19.5% trivial, 7.8% mild, 2.6% moderate), mild subvalvular pulmonary stenosis in 1.3%, pulmonary insufficiency in 2.6%. CONCLUSION: The study confirms good midterm results after neonatal arterial switch operation for transposition with or without ventricular septal defect. Long-term observation is necessary to assess rhythm, coronary artery and myocardial function as well as development of neo-aorta and pulmonary artery system.

Child↗
PubMed1997

Polarity reversal improves defibrillation efficacy in patients undergoing transvenous cardioverter defibrillator implantation with biphasic shocks.

The purpose of this study was to determine the influence of polarity reversal on DFT in patients undergoing implantation of nonthoracotomy defibrillators with biphasic shocks. Previous studies have shown higher defibrillation efficacy with using the distal electrode as anode implantation of nonthoracotomy defibrillators and monophasic shocks. However, it is as yet unclear whether biphasic shock defibrillation will also be influenced by polarity reversal. Using a transvenous lead system with a proximal electrode in the superior caval vein and a distal electrode in the RV apex, 27 patients undergoing defibrillator implantation were randomized to DFT testing "initial" (distal electrode = cathode) or "reversed" polarity (distal electrode = anode). Defibrillation energy was reduced stepwise until defibrillation failure occurred. At this point, polarity was switched and testing continued until the lowest energy requirement was determined for both polarities. With reversed polarity, DFT was 11.1 +/- 5.7 J versus 13.3 +/- 5.8 J with polarity (P = 0.033). This means a 17% reduction of the DFT. In 10 patients, the threshold was lower with reversed, whereas in 3 patients it was lower with initial polarity. In conclusion, changing electrode polarity in transvenous implantable defibrillators with biphasic shocks may significantly influence defibrillation energy requirements. Therefore, polarity reversal should always be attempted before considering patch implantation.

Adult↗
PubMed1997

Thoracic sequelae after surgical closure of the patent ductus arteriosus in premature infants.

Thirty-six children (median chronological age 6 years 1 month) who had undergone surgical closure of a patent ductus arteriosus through a left posterolateral thoracotomy in the neonatal period (median gestational age 32 weeks) were investigated prospectively with respect to anatomical and functional changes of the chest. At follow-up examination, residual or recurrent patent ductus arteriosus was not observed. Three patients had chronic bronchial obstruction. Two patients showed pathological musculoskeletal thoracic sequelae that did not require any treatment at the time of follow-up; persistence of immediate postoperative left phrenic palsy (n = 1) and thoracic scoliosis (n = 1). Twenty of the 27 patients in whom chest X-ray was performed had minor radiological skeletal anomalies in the form of rib deformation or fusion related to the thoracotomy, lesions which have a potential to induce thoracic scoliosis. Left shoulder elevation at chest X-ray and isolated left arm dysfunction at clinical examination were not observed. Despite the low incidence of scoliosis and the absence of left arm dysfunction observed at mid-term follow-up in our series, the incidence of minor rib deformations with a potential to induce severe anomalies such as scoliosis should motivate late follow-up examination at adolescence to definitively assess the prevalence of thoracic sequelae after surgical closure of the patent ductus arteriosus in premature infants.

Bronchial Diseases↗
PubMed1997

Effect of myocardial viability assessed by technetium-99m-sestamibi SPECT and fluorine-18-FDG PET on clinical outcome in coronary artery disease.

UNLABELLED: PET imaging of myocardial perfusion and metabolism identifies regional viability as well as patients at high risk for future cardiac events. This study evaluated a combined "hybrid" imaging approach using 99mTc-sestamibi SPECT and [18F]fluoro-2-deoxy-D-glucose (FDG) PET with regard to reversibility of regional dysfunction and to patient clinical outcome during a 2-yr follow-up. METHODS: In this study, 161 consecutive patients underwent baseline viability imaging. All had regional wall motion (RWM) abnormalities and 88% had a history of previous myocardial infarction. Regions were classified by semiquantitative analysis of sestamibi and FDG uptake as normal, mild match, mismatch or scar. For clinical outcome, patients were divided into three groups: predominantly scar tissue (Group A, n = 90), mild match (Group B, n = 26) and mismatch (Group C, n = 45). Treatment was performed with the knowledge of nuclear results. Cardiac events during follow-up were defined as death, myocardial infarction, unstable angina requiring revascularization, heart transplantation and survived resuscitation. RESULTS: Patients were followed for 29 +/- 6 mo. Revascularization rate was 30% in Group A, 81% in Group B and 80% in Group C, whereas the other patients were treated by medication. Only Group C demonstrated a significant reduction of cardiac events after revascularization, whereas, particularly in Group A, revascularization did not influence the frequency of events. Subjective assessment of angina pectoris and heart failure revealed more patients with improvement after revascularization as compared with conservative treatment. Of the 84 revascularized patients, 61 underwent follow-up angiography at 5 +/- 2 mo with RWM analysis using the centerline method. RWM improved only in mismatch regions from -2.2 +/- 1.0 s.d. to -1.0 +/- 1.4 s.d. (p < 0.01), whereas regions with a mild match or scar did not change. CONCLUSION: Nuclear imaging using 99mTc-sestamibi SPECT and [18F]FDG PET allows diagnosis of viability in regions with reduced perfusion and function with prognostic implications for functional outcome as well as for identification of patients who benefit most from revascularization.

Angioplasty, Balloon, Coronary↗