[Regeneration of the axotomised sciatic nerve in dogs using the tubulisation technique with Chitosan biomaterial preloaded with progesterone]. / Regeneracion del nervio ciatico axotomizado del perro mediante la técnica de tubulizacion con el biomaterial quitosana precargado con progesterona.

INTRODUCTION: Injuries to peripheral nerves can have different causes and may lead to disorders affecting mobility, sensitivity and loss of motor function as they progress. Weiss, in 1944, introduced tubulisation to promote the regeneration of a sectioned nerve. In this study the biomaterial Chitosan was used to induce and stimulate the regeneration of the sciatic nerve in dogs. At the same time, we took advantage of the characteristics offered by Chitosan to include the neurosteroid progesterone in its matrix, as a promoter of axonal growth. AIMS. The aim of our study was to determine the degree of regeneration of the sciatic nerve in dogs when axotomised tubulised with a Chitosan prosthesis steeped in the neurosteroid progesterone. MATERIALS AND METHODS: Young adult female dogs were used to evaluate the regeneration of the sciatic nerve induced at a standard of 15 mm; regeneration was determined by means of an axonal growth chamber. Nerve growth was studied through histological analysis and by electron microscope. RESULTS: The statistical analysis showed that there were no significant differences in the number of myelinated fibres between the experimental groups. The electron microscope images of the transmission in the regenerated nerves in the groups that were tubulised with Chitosan, with and without neurosteroid preloading, revealed an advanced regenerative process. This was evidenced by the fact that collagen fibres, elastin, Schwann cells and both myelinated and non myelinated fibres were observed in all cases. CONCLUSIONS: The regeneration of axotomised, tubulised nerves was achieved regardless of the treatment that was applied. The distal nerve segment that was analysed revealed a similar structure to that of a normal nerve.

Percutaneous balloon mitral valvuloplasty in comparison with open mitral valve commissurotomy for mitral stenosis during pregnancy.

OBJECTIVES: We sought to compare the maternal and fetal outcomes of patients with severe mitral stenosis submitted to percutaneous balloon dilation versus open mitral valve commissurotomy (MVC) during pregnancy. BACKGROUND: Heart failure in patients with mitral stenosis complicating pregnancy is a common problem in developing countries. Since 1984, percutaneous dilation of the mitral valve using a balloon catheter has become a therapeutic alternative to open heart surgery. Although the efficacy of percutaneous mitral valve balloon dilation is well established, its results have never before been compared with the results of commissurotomy during pregnancy. METHODS: We compared the clinical and obstetric complications in 45 women who were treated with percutaneous mitral valve balloon dilation (group I, n = 21; from 1990 to 1995) or open MVC (group II, n = 24; from 1985 to 1990) for severe heart failure due to mitral stenosis during pregnancy. RESULTS: In our study, percutaneous balloon dilation of the mitral valve had a success rate of 95% (Gorlin formula) and 90.5% (echocardiographic "pressure half-time" method), as demonstrated by the final mitral valve area achieved. This improvement was followed by a marked decrease in the mitral valve gradient, left atrial pressure and mean pulmonary artery pressure. Patients in both groups had similar improvements in symptoms. Patients who underwent percutaneous balloon dilation had significantly fewer fetal complications, with a reduction in fetal and neonatal mortality (1 death in group I vs. 8 in group II, p = 0.025). CONCLUSIONS: Percutaneous balloon mitral valvuloplasty is safe and effective and appears to be preferable for the fetus, compared with open MVC during pregnancy.

Noninvasive diagnosis of allograft vascular disease after heart transplantation.

OBJECTIVE: To determine the predictive values of noninvasive tests for the detection of allograft vascular disease. METHODS: We studied 39 patients with mean ages of 48+/-13 years and a follow-up period of 86+/-13 months. The diagnosis of allograft vascular disease was made by cine-coronary arteriography, and it was considered as positive if lesions existed that caused > or =50% obstruction of the lumen. Patients underwent 24h Holter monitoring, thallium scintigraphy, a treadmill stress test, and dobutamine stress echocardiography. Sensitivity, specificity, and positive and negative predictive values were determined in percentages for each method, as compared with the cine-coronary arteriography results. RESULTS: Allograft vascular disease was found in 15 (38%) patients. The Holter test showed 15.4% sensitivity, 95.5% specificity. For the treadmill stress test, sensitivity was 10%, specificity was 100%. When thallium scintigraphy was used, sensitivity was 40%, specificity 95.8%. On echocardiography with dobutamine, we found a 63.6% sensitivity, 91.3% specificity. When the dobutamine echocardiogram was associated with scintigraphy, sensitivity was 71.4%, specificity was 87%. CONCLUSION: In this group of patients, the combination of two noninvasive methods (dobutamine echocardiography and thallium scintigraphy) may be a good alternative for the detection of allograft vascular disease in asymptomatic patients with normal ventricular function.

Extrinsic compression of the left main coronary artery by a dilated pulmonary artery: clinical, angiographic, and hemodynamic determinants.

Extrinsic compression of the left main coronary artery (LMC) by the pulmonary artery (PA) is a very unusual and poorly understood entity, usually associated with the presence of adult congenital heart disease. We identified 12 patients (age range, 6 months to 55 years) with LMC stenosis (> or = 50%) presumably secondary to compression by a dilated main PA and related to various forms of heart disease (11 congenital, 1 pulmonary hypertension). In all cases, the main PA was dilated with the main PA/aortic root diameter increased (mean, 2.0; normal value, < or = 1.0), and in all but two, PA pressures were increased (> 30 mm Hg systolic). Left coronary trunk stenosis was usually visualized in only one angiographic view (best seen in 45 degrees left anterior oblique, 30 degrees cranial projection). The LMC also appeared to be inferiorly displaced and in close contact with the left aortic sinus (mean angle between sinus and LMC was 23 degrees +/- 13 degrees, a control group was 70 degrees +/- 15 degrees ). In one patient, surgical correction of the dilated PA was associated with a reduction in LMC stenosis from 85% to < 50% and less inferior left main displacement (from 25 degrees to 50 degrees ). Patients with a dilated main PA may exhibit extrinsic LMC compression leading to significant eccentric narrowing and downward displacement of the LMC. In the presence of significant dilatation of the main PA from any etiology, functional and/or anatomic studies should be performed to exclude significant LM obstruction.

High versus low-pressure balloon inflation during multilinktrade mark stent implantation: acute and long-term angiographic results.

We compared the impact of low and high-pressure balloon inflation on acute and late angiographic results of Multilink stent. Low-pressure balloon inflation (9.5 +/- 1.9 atm) was used in 43 stents and high pressure (17.1 +/- 1.5 atm) in 44. A larger immediate luminal gain was achieved in stents with high-pressure balloon inflation (1.80 +/- 0.26 vs. 1.47 +/- 0.62; P = 0.002), resulting in a larger mean diameter in this group (2.71 +/- 0.37 vs. 2.48 +/- 0.47; P = 0.017). At follow-up, a larger luminal diameter was achieved in the high pressure group (1.93 +/- 0.72 vs. 1.45 +/- 0.66; P = 0.002) and a trend to a lower rate of angiographic restenosis (15% vs. 38%, P = 0.08).

[Synchronous neoplasias in colorectal cancer]. / Neoplasias sincrónicas en cáncer colorrectal.

OBJECTIVE: The aim of this study was to show the incidence of synchronous lesions in colorectal cancer patients treated surgical at our service. SUMMARY BACKGROUND DATA: Many studies have shown different incidences of synchronous lesions in colorectal cancer, mainly due to variations in the accuracy of the diagnostic methods used and the intentional search for associated lesucosal. METHOD: Fifty-eight clinical records of patients operated on for colorectal cancer were retrospectively reviewed from August 1995 to March 1999. The synchronous lesions were classified as benign or malignant lesions based on its histological classification. Statistical analysis was carried out by the Spearman coefficient correlation. RESULTS: Fifteen patients (25.8%) had 28 synchronous lesions, nine were male (60%), and six females (20%). The average age was 63.2 years with a range of 26 to 83 years. The endoscopic diagnosis of synchronous lesions was performed preoperatively in 12 patients (80%). The most frequent localization's of primary tumor was the sigmoid colon in six patients (40%). The more frequent localization of synchronous lesions was the rectum (35.7%). Benign lesions were most commonly found in synchronous lesions (89.3%). CONCLUSIONS: The patient with colorectal cancer has an unstable epithelium and an uncommon predisposition to develop several mucosal alterations. This predisposition is prone to grow benign or malignant lesions. For this reason, we advise all that patient with colorectal cancer be fully studied endoscopically.

[Anorectal surgery in patients infected with human immunodeficiency virus]. / Cirugía anorrectal en pacientes infectados por el virus de la inmunodeficiencia humana.

OBJECTIVE: The aim of this study was to describe the clinical characteristics of the patients infected with the human immunodeficiency virus (HIV), who were submitted to anorectal surgery with emphasis on healing time and complications. METHODS: The patients were evaluated prospectively from July 1998 to July 1999; there was a total of 23 patients HIV (+) (Group 1). They were compared to a control group of randomly chosen HIV (-) patients (Group II) to establish the characteristics of each group, the morbidity, and the time of healing. The statistical analysis was performed with the student T test. RESULTS: In Group I, the diagnosis were fistula in the anus, anal fissure, anal abscess, condylomata acuminata, anal ulcer, and cutaneous flaps. Seven patients had a fistulotomy, a drainage of abscess in one, resection of different skin lesions in 12, electrofulguration of condylomata in two, fisturectomy in three and solely biopsy in three. The average healing time was 26.087 days for Group I and 23.21 days for Group II. A comparison between healing time and complications in these two groups was carried out to determine a whether significant difference exists in these parameters. There was no significant difference between these groups, but there were unequal rates of healing (26.087, DE +/- 10.778 days vs 23.21 DE +/- 6.259 days; p = not significant) and complications for the similar procedures. CONCLUSIONS: The healing in time HIV (+) patients submitted to anorectal surgery may not vary important when compared with HIV (-) patients.

Angiographic and electrophysiological substrates for ventricular tachycardia mapping through the coronary veins.

OBJECTIVE: To study the value of epicardial mapping through the coronary venous system in patients with sustained ventricular tachycardia. DESIGN: 20 consecutive patients with sustained ventricular tachycardia who were candidates for radiofrequency ablation. SETTING: Electrophysiological laboratory. INTERVENTIONS: Coronary venous angiography was performed with a catheter, which provided coronary sinus occlusion during injection of contrast media. Multipolar microelectrode catheters were then manoeuvred into the tributaries of coronary sinus, using an over-wire system or an on-wire system. An endocardial ablation catheter was positioned in the left ventricle. Conventional programmed ventricular stimulation was performed for sustained ventricular tachycardia induction. Endocardial radiofrequency ablation was performed using impedance or temperature monitoring. RESULTS: Coronary veins were catheterised in all patients; 20 had induction of sustained ventricular tachycardia, 14 were stable. Presystolic epicardial electrograms were recorded in six patients and concealed entrainment in two, helping as a landmark for endocardial ablation. After simultaneous epicardial and endocardial mapping, successful endocardial radiofrequency ablation was achieved in nine of 14 patients with stable ventricular tachycardia (64%). CONCLUSIONS: Epicardial mapping through the coronary veins in patients with ventricular tachycardia is feasible, safe, and can be a useful landmark for endocardial catheter mapping and ablation.

Chagas' disease reactivation after heart transplantation: efficacy of allopurinol treatment.

BACKGROUND: Chagas' disease is a parasitic infection that provokes a severe form of dilated cardiomyopathy. In the initial experience with heart transplantation with Chagas' disease, a high rate of acute reactivation has been reported. Although benzinidazole and nifurtimox are effective in the treatment of reactivation or of the acute phase of the disease they are associated with important adverse effects. Allopurinol has substantial activity against Trypanosoma cruzi in vitro, in the experimental laboratory and in chronic human Chagas' disease; however, there is no information regarding its action in Chagas' reactivation after heart transplantation. METHODS AND RESULTS: We describe two patients with Chagas' disease who underwent heart transplantation. The first one had asthenia, anorexia, and several painful subcutaneous nodules in the legs after transplantation; biopsy showed an inflammatory infiltrate with intracytoplasmatic nests of Trypanosoma cruzi, confirmed by immunohistochemical stains with monoclonal antibodies specific to parasitic antigens. Allopurinol (600 mg/day) produced complete regression of the symptoms and the nodules with a negative control biopsy within 2 weeks. Treatment was maintained for 2 months. Mild leukopenia developed which improved after azathioprine reduction, and no further side-effects were noted. The second patient had sudden heart failure months after transplantation; endomyocardial biopsy showed myocardial fibers infested with Trypanosoma, and a concomitantly performed right heart catheterization showed a low cardiac index and highfilling pressures. The patient received allopurinol at a daily dose of 900 mg and conventional treatment for heart failure. Echocardiogram showed improved wall motion and decreased left ventricular dimensions, and control biopsy showed no inflammatory activity; cardiac index and filling pressures normalized. Treatment was maintained for 2 months without side effects. The two patients have not had recurrences and were in New York Heart Association functional class I 12 and 3 months, respectively, after discontinuation of allopurinol. CONCLUSIONS: Allopurinol seems to be safe and effective in treating Chagas' disease reactivation after heart transplantation. A larger number of case studies seems to be necessary to properly evaluate its role in the treatment of Chagas' disease reactivation.

Physiologic multivalvular regurgitation during pregnancy: a longitudinal Doppler echocardiographic study.

Valvular function, assessed by Doppler technique, has not been extensively investigated during normal pregnancy. To prospectively study this feature, 18 normal pregnant women were followed during their pregnancies and puerperium, with serial clinical and pulsed-continuous Doppler echocardiographic examinations. In four gestational periods and the puerperium, we analysed: (a) ventricular and atrial dimensions, as well as valve annular diameters; (b) prevalence and characteristics of trivial valvular regurgitations. During pregnancy, slight but significant increases of the four cardiac chamber dimensions and valve annular diameters were observed, except for the aortic ring. The prevalence of physiologic valvular regurgitation in early pregnancy (mitral, 0%; tricuspid, 38.9%; pulmonary, 22.2%; aortic, 0%), was similar to a control group of 18 healthy non-pregnant women. As pregnancy evolved, there was a progressive and significant increase of multivalvular regurgitation, maximal at full-term (mitral, 27.8%; tricuspid, 94.4%; pulmonary, 94.4%, P < 0.05 vs. early pregnancy). Aortic regurgitation was not detected in any stage of pregnancy. In the puerperium, mitral regurgitation resolved, but tricuspid and pulmonary regurgitation were still significantly prevalent (83.3% and 66.7%, respectively, P < 0.05 vs. early pregnancy). It is concluded that physiologic multivalvular regurgitation is frequent in pregnancy, mainly involving right-sided valves in late gestational periods, occasionally persisting in the early puerperium. Chamber enlargement, valve annular dilatation, and increased prevalence of trivial valve regurgitation are time-related events during normal pregnancy, resulting from a reversible cardiac remodeling process induced by physiologic volume overload. These aspects should be considered for a correct interpretation of Doppler echocardiographic findings in pregnant women with suspected heart disease.

Cardiopulmonary exercise testing early after catheter-balloon mitral valvuloplasty in patients with mitral stenosis.

Seven female patients (age 27 to 53 yr) with significant mitral stenosis performed continuous, incremental, maximal treadmill exercise tests the day before and within 3-5 days after catheter-balloon valvuloplasty. Mitral valve area determined by the echo-Doppler method increased from 0.9 +/- 0.3 cm2 to 1.9 +/- 0.7 cm2 (p < 0.02). Mean left atrial pressure was reduced from 24 +/- 8 to 13 +/- 7 mmHg (p < 0.01) and mean pulmonary artery pressure from 36 +/- 13 to 28 +/- 10 mmHg (p < 0.02) with a non-significant increase in cardiac output from 3.6 +/- 1.2 to 4.0 +/- 1.7 l/min. After catheter-balloon valvuloplasty all patients reached a higher maximal workload during exercise, and mean value of oxygen consumption and pulmonary ventilation were significantly lower in submaximal workloads. The calculated ventilatory equivalent for oxygen was significantly reduced in submaximal and in maximal workloads after catheter-balloon valvuloplasty. Peak oxygen consumption and the ventilatory anaerobic threshold were not changed after catheter-balloon valvuloplasty (pre 15.59 +/- 2.72 vs post 16.90 +/- 3.44 and pre 12.10 +/- 2.55 vs post 12.62 +/- 2.71 ml/kg/min, respectively). We concluded that after catheter-balloon valvuloplasty the cost of breathing was reduced and the oxygen consumed was more effectively utilized during exercise. Increases in peak oxygen consumption and in ventilatory anaerobic threshold would require circulatory and metabolic adaptations in response to increased physical activity and were not observed when cardiopulmonary tests were performed early after catheter-balloon valvuloplasty.

Pregnancy in patients with prosthetic heart valves: the effects of anticoagulation on mother, fetus, and neonate.

Maternal and fetal complications in a consecutive series of 60 pregnancies in 49 patients with prosthetic heart valves were prospectively evaluated. Group 1 consisted of 40 pregnancies in 31 patients who were taking oral anticoagulants. No oral anticoagulation was used in 20 pregnancies in 19 patients (group 2). In group 1 there were three instances of acute valvular thrombosis during the 35 pregnancies in patients with mechanical prostheses, with two maternal deaths. There were two episodes of cerebral embolism, one in group 1 and one in group 2. Patients with isolated aortic valve replacement had fewer maternal complications (2 of 13) than patients with isolated mitral valve replacement (15 of 42) without statistical significance. Severe bioprosthesis dysfunction occurred in 4 of 25 pregnancies (one rupture and three stenosis) with two maternal deaths, one in the puerperium and the other in the postoperative period of cardiac surgery during pregnancy. When analyzing obstetric events we observed seven spontaneous abortions and one hydatidiform mole. All spontaneous abortions occurred in group 1. The incidences of prematurity and low birth weight were significantly higher in group 1 than in group 2 (46.6% vs 10.5%, p less than 0.05, and 50% vs 10.5%, p less than 0.05, respectively). Moreover, there was a significant association between prematurity and the mother's New York Heart Association functional class (61.5% in classes III and IV vs 22.2% in classes I and II, p less than 0.05). There were five neonatal deaths, all in group 1 (p = NS vs group 2). Three infants had warfarin-related congenital defects.(ABSTRACT TRUNCATED AT 250 WORDS)

Chagas cardiomyopathy and captopril.

Chagas disease is a leading cause of heart failure in Latin America. Sudden death occurs in approximately 40% of patients with heart failure due to Chagas disease. We report a single blind, cross-over trial of prolonged treatment with captopril and placebo in 18 Chagas disease patients with class IV NYHA heart failure. Ventricular dimensions, neurohormones, electrolytes and ventricular arrhythmias were analysed in 11 men and seven women receiving stable doses of digoxin and frusemide who were randomly divided into two intervention groups. Group I patients were given increasing doses of captopril up to 150 mg.day-1 maintained for 6 weeks, group II received the placebo. A 24 h Holter, 2-D echocardiogram, urinary catecholamines, plasma renin and electrolyte determinations were performed at the end of each phase. After a 2-week washout period, the two groups crossed over and another period of 6 weeks was observed. Ventricular arrhythmias were analysed by either Mann-Whitney or the Wilcoxon test. Remaining data were assessed by the Student t-test. A significant reduction in heart rate and urinary catecholamine levels, and enhanced plasma levels of renin, together with a reduction in ventricular couplets was found in the captopril-treated group. We conclude that captopril has a beneficial effect on neurohormones with a subsequently reduced heart rate and diminished incidence of ventricular arrhythmias in patients with Chagas disease. This effect might result in a reduction of mortality caused by the disease, suggesting the need for further investigations.

Absence of an aortic valve cusp, a cause of severe aortic regurgitation in infancy.

Congenital aortic regurgitation is an extremely rare cardiac lesion. This is a case report of an infant with a severe degree of valve regurgitation due to absence of the noncoronary aortic cusp. We show the echocardiographic, angiographic, and surgical aspects of the case, emphasizing the importance of a precise anatomical diagnosis and the problems of early valve replacement.

Lung and myocardial thallium-201 kinetics in resting patients with congestive heart failure: correlation with pulmonary capillary wedge pressure.

Increased lung thallium-201 activity occurs with exercise in patients with severe coronary artery disease as a result of increased pulmonary capillary wedge pressure. No study has shown resting lung kinetics in chronic congestive heart failure. To better understand the relationship between lung and myocardial thallium uptake and pulmonary capillary wedge pressure, this study was performed. Resting lung and myocardial thallium uptake, expressed as a ratio, were compared with simultaneous pulmonary capillary wedge pressure in 16 patients with congestive heart failure and cardiomyopathy, all New York Heart Association class IV. There were no variations in pulmonary capillary wedge pressure throughout the study protocol. There was a significant reduction in the lung/myocardium thallium ratio from 10 to 60 minutes (0.83 +/- 0.30 to 0.59 +/- 0.17; p less than 0.001). At 60 minutes after thallium injection there was a linear correlation between the lung/myocardium ratio and capillary wedge pressure with an r value of 0.62 (p less than 0.01). Thus thallium-201 washout is rapid despite persistence of pulmonary capillary wedge pressure elevation, indicating that clearance does not imply resolution of congestive heart failure. In addition, a significant but imprecise correlation was found between capillary pressure and the lung/myocardium ratio. Rapid changes in lung activity during the early postinjection period may limit the clinical use of the lung/myocardium ratio.

Segmental atrial fibrillation resulting in chronic atrial dissociation. A case report.

Atrial arrhythmias are diagnosed on the basis of the analysis of P wave morphology, timing and rate, the surface electrocardiogram, and intracardiac recordings. Recent intracardiac studies have demonstrated dissimilar atrial rhythms with direct intra-atrial recordings, the former otherwise not evident on the surface ECG (Zipes et al. 1972, Wu et al. 1975, Friedman et al. 1974, Gomes et al. 1981). This paper reports the electrocardiographic diagnosis of atrial dissociation made on the surface electrocardiogram. The findings suggest the following: (1) That sinus rhythm exists, with the dominant sinus rhythm depolarizing the major portion of the right as well as the left atrium; (2) Atrial fibrillation localized specifically to lead III, and at times to leads III and AVL, on the surface electrocardiogram; and (3) Intraesophageal recordings and echocardiography revealed an area of the posterior right and left atria that had wall motion abnormalities and electrical activity compatible with those of atrial fibrillation.