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Biomedical subjects

L F Moreira

Publications and source records attributed to L F Moreira.

At least 37 records · Page 2Linked to original sources
PubMed1997

Clinical outcome after left ventricular surgical remodeling in patients with idiopathic dilated cardiomyopathy referred for heart transplantation: short-term results.

BACKGROUND: Left ventricular partial ventriculectomy (LVPV), an unconventional operation to reverse some aspects of the cardiac remodeling, has been proposed for treatment of congestive heart failure. METHODS AND RESULTS: Twenty-four patients (age 46+/-9 years) referred to heart transplantation underwent isolated LVPV or LVPV associated to valve annuloplasty. Patients were in New York Heart Association functional class IV (15) or III (9) due to idiopathic dilated cardiomyopathy. Functional class, left and right ventricular ejection fraction (radionuclide), left ventricular end-diastolic and end-systolic diameter, and fractional shortening (by echocardiography), and hemodynamic variables were determined. The mean follow-up was 474+/-174 days. Survival at 30, 180, and 365 days was 92+/-6%, 67+/-10%, and 63+/-10%, respectively. Nine patients died, and the cause was associated with arrhythmias in 4 patients. The left ventricular end-diastolic diameters before and at 23+/-14 days, 188+/-27, and 365+/-14.8 days of follow-up were 82.6+/-9.8, 68.9+/-7.8, 69.9+/-6.9, and 70+/-5.3 mm, respectively (P=0.0001). The left ventricular end-systolic diameters were 73.5+/-7.4, 55.9+/-7.5, 57.4+/-7.8, and 55+/-5.5 mm (P=.0001). Fractional shortenings were 13+/-3, 19+/-4, 18+/-5, and 22+/-2%, respectively (P=.0001). The left ventricular ejection fractions before and 18+/-14, 188+/-26, and 369+/-3.6 days after the surgery were 17.2+/-4.7, 24.5+/-8.3, 24.5+/-7.4, and 23.7+/-6.1%, respectively (P=.004). The right ventricular ejection fractions were 20.5+/-6.2, 27.9+/-8.4, 28.2+/-10.1, and 27.4+/-7.3% (P=0.02). Pressures were unchanged. There was improvement in cardiac index from 2.11+/-0.52 to 2.53+/-0.64 L/min (P=.0037). Norepinephrine blood levels reduced from 702+/-258 to 439+/-307 pg/mL (P=.001). Most surviving patients presented improvement in functional class. Sustained ventricular tachycardias were observed in 9 patients (38%). CONCLUSIONS: The left ventricular partial ventriculectomy may improve the left and right ventricular function, functional class, and cardiac output. These initial results were associated to high prevalence of sustained ventricular tachycardia. The ventriculectomy introduces the concept that reduction of left ventricular chamber diameter may improve cardiac function in heart failure. Further progress is necessary to improve the results and evaluate its proper role in the management of heart failure.

Adult↗
PubMed1997

Respiratory mechanics and morphometric changes during pneumoperitoneum in normal rats.

Pneumoperitoneum may give rise to several respiratory changes; nevertheless, no comprehensive analysis of respiratory mechanics has been performed under this condition. Respiratory mechanics and thoracoabdominal morphometry were evaluated in six sedated, anaesthetized, paralysed, and mechanically-ventilated rats before (control) and during pneumoperitoneum. After airway occlusion at end-inspiration, respiratory system, pulmonary, and chest wall resistive pressures (deltaP1,rs, deltaP1,L and deltaP1,cw, respectively) and viscoelastic/inhomogeneous pressures (deltaP2,rs, deltaP2,L and deltaP2,cw, respectively) were determined. Total pressure changes (deltaPtot) were calculated as the sum of deltaP1 and deltaP2, yielding the values of deltaPtot,rs, deltaPtot,L and deltaPtot,cw, respectively. Respiratory system, lung, and chest wall static (Est,rs, Est,L and Est,cw, respectively), and dynamic elastances (Edyn,rs, Edyn,L and Edyn,cw, respectively), and the corresponding changes in elastance (deltaE) (calculated as Edyn-Est) were also obtained. Chest wall configuration both at functional residual capacity (FRC) and end-inspiration (FRC + tidal volume (VT)) was also evaluated in another four rats. Pneumoperitoneum significantly increased deltaPtot,rs, deltaPtot,cw, deltaP2,rs, deltaP2,cw, deltaErs, deltaEcw, Est,rs, Est,L and Est,cw. Lateral and anteroposterior diameters increased significantly, with the exception of lateral diameters at the level of crista iliaca. Cephalocaudal diameter and FRC decreased. In conclusion, pneumoperitoneum augments elastances and increases the pressure dissipated against viscoelasticity/inhomogeneity of the respiratory system and chest wall. These changes are related to a cephalad displacement of the diaphragm plus changes in thoracoabdominal configuration.

Animals↗
PubMed1997

Evolution of circadian organization in vertebrates.

Circadian organization means the way in which the entire circadian system above the cellular level is put together physically and the principles and rules that determine the interactions among its component parts which produce overt rhythms of physiology and behavior. Understanding this organization and its evolution is of practical importance as well as of basic interest. The first major problem that we face is the difficulty of making sense of the apparently great diversity that we observe in circadian organization of diverse vertebrates. Some of this diversity falls neatly into place along phylogenetic lines leading to firm generalizations: i) in all vertebrates there is a "circadian axis" consisting of the retinas, the pineal gland and the suprachiasmatic nucleus (SCN), ii) in many non-mammalian vertebrates of all classes (but not in any mammals) the pineal gland is both a photoreceptor and a circadian oscillator, and iii) in all non-mammalian vertebrates (but not in any mammals) there are extraretinal (and extrapineal) circadian photoreceptors. An interesting explanation of some of these facts, especially the differences between mammals and other vertebrates, can be constructed on the assumption that early in their evolution mammals passed through a "nocturnal bottleneck". On the other hand, a good deal of the diversity among the circadian systems of vertebrates does not fall neatly into place along phylogenetic lines. In the present review we will consider how we might better understand such "phylogenetically incoherent" diversity and what sorts of new information may help to further our understanding of the evolution of circadian organization in vertebrates.

Animals↗
PubMed1996

Dynamic cardiomyoplasty in South America.

BACKGROUND: Dynamic cardiomyoplasty has been proposed in the treatment of severe cardiomyopathies. However, few reports to date have shown significant numbers of patients collected on a multicenter basis. METHODS: From July 1987 to June 1994, dynamic cardiomyoplasty was performed in 112 patients in South America. The indications were dilated cardiomyopathy in 96 patients, Chagas' disease cardiomyopathy in 13, and ischemic cardiomyopathy in 3. Left latissimus dorsi muscle was used in all patients. RESULTS: The thirty-day mortality rate was 8.1%, and patients were followed up for 22.1 +/- 18.6 months. Data of surviving patients show that 47.3% were in New York Heart Association functional class I, 45.6% in class II, and 7% in class III or IV 1 year after the operation. The 1-year survival was 78.4%; 2-year, 59.7%; and 5-year, 41.7%. The survival at 1 year was 86.1% for patients with dilated cardiomyopathy and 40% for those with Chagas' disease. At 5 years, these values were 49.8% and 9.5%, respectively. Long-term survival was also significantly affected by preoperative functional class and pulmonary vascular resistance. However, patients operated on in class III or intermittent class IV and without elevated pulmonary vascular resistance had survival rates of 91.5% at 1 year and 76.7% at 5 years of follow-up. CONCLUSIONS: Cardiomyoplasty improves the functional status of patients with severe cardiomyopathies. Otherwise, long-term survival after this procedure is limited in patients with Chagas' disease and by patients' condition before the operation.

Adult↗
PubMed1996

Right internal thoracic artery through the transverse sinus in myocardial revascularization.

BACKGROUND: This study presents the late patency rate of the right internal thoracic artery (ITA) used in situ through the pericardium transverse sinus to the circumflex artery and its branches. METHODS: From April 1983 to December 1994, 2,642 patients were submitted to myocardial revascularization; 201 of them had bilateral ITAs. The right ITA through the transverse sinus was grafted to obtuse marginal artery in 170 patients (84.5%) and the left ITA was grafted to the anterior descending artery in 188 patients (93.5%). Angiographic studies were performed in 80 patients, 44 patients in the immediate postoperative period and 36 patients in the late follow-up (mean, 51.6 months). RESULTS: The right ITA was patent in 75 patients (93.7%) and the left ITA was patent in 77 (96.2%). At the late postoperative period, the right ITA was patent in 33 patients (91.6%) and the left ITA was patent in 34 (94.4%). CONCLUSIONS: The right ITA placed through the pericardium transverse sinus has a good long-term patency rate, similar to that observed with the left ITA and superior to that of saphenous vein grafts for myocardial revascularization.

Actuarial Analysis↗
PubMed1996

Long-term outcome, survival analysis, and risk stratification of dynamic cardiomyoplasty.

METHODS: To analyze the long-term outcome of dynamic cardiomyoplasty, we retrospectively studied 127 consecutive patients who underwent this procedure in Paris, France (n = 76), São Paulo, Brazil (n = 37), and Portland, Oregon (n = 14). Preoperative data were collected for patients operated on between January 1985 and June 1994 and examined with respect to effect on long-term survival. Patients had a mean age of 50 +/- 13 years and were predominantly male (82%). In 46% the cause of disease was ischemic. Concomitant operations were performed in 22 patients. RESULTS: Operative mortality was 12% (15/127). Kaplan-Meier survival +/- standard error at 1 through 5 years was 73% +/- 4%, 57% +/- 5%, 49% +/- 6%, 44% +/- 6%, and 40% +/- 7%, respectively. There was a distinct improvement at 6 months in New York Heart Association functional class (3.2 +/- 0.05 vs 1.7 +/- 0.07, p < 0.0001) and a small but significant increase in left ventricular ejection fraction (20% +/- 0.8% vs 23% +/- 1.5%, p = 0.04). Ninety-day mortality was associated with low right ventricular ejection fraction, a blunted hemodynamic response to exercise testing, and requirement for an intraaortic balloon pump at the time of the operation. Using a stepwise Cox regression method of multivariable survival analysis (n = 101), we determined that atrial fibrillation, New York Heart Association class IV, high pulmonary capillary wedge pressure, and balloon pump use were independent variables simultaneously associated with poor overall survival. When metabolic testing variables were added to this model, peak oxygen consumption eliminated both pulmonary capillary wedge pressure and functional class from the model, albeit with fewer (n = 74) patients. CONCLUSION: Dynamic cardiomyoplasty is an evolving therapy for symptomatic congestive heart failure, the results of which may be enhanced by intelligent, risk-sensitive patient selection.

Cardiomyoplasty↗
PubMed1996

Mid-term results of heart transplantation, cardiomyoplasty, and medical treatment of refractory heart failure caused by idiopathic dilated cardiomyopathy.

BACKGROUND: Heart transplantation is the surgical procedure of choice for treatment of refractory heart failure. However, it benefits a small number of patients because of the limited number of donors and selection criteria of recipients. Cardiomyoplasty is an alternative surgical procedure for heart failure. The aim of this investigation was to report our experience with heart transplantation, cardiomyoplasty, and clinical treatment of heart failure caused by idiopathic dilated cardiomyopathy. METHODS: Ninety patients with refractory heart failure caused by idiopathic dilated cardiomyopathy were observed from May 1988 to March 1993. The patients had New York Heart Association functional class III or IV symptoms. The patients were divided in three groups according to the treatment received: heart transplantation (33 patients), cardiomyoplasty (25 patients), or medical treatment (32 patients). We studied the event-free curve, the New York Heart Association functional class, the left ventricular ejection fraction, and the morbidity of the groups in the follow-up of 19 +/- 16 months. We considered as an event death or crossover to another group because of severe symptoms. RESULTS: The event-free rate in the cardiomyoplasty group was 92%, 88%, 79%, 74%, and 62% at 3, 9, 12, 18, and 24 months of follow-up, respectively. The event-free rate after heart transplantation was 82%, 78%, 82%, 75%, and 69% at 3, 9, 12, 18, and 24 months, respectively. The event-free rate in the medical treatment group was 78%, 65%, 61%, 48%, and 48% at 3, 9, 12, 18, and 24 months, respectively. All surviving patients in the heart transplantation group had functional class I symptoms. After cardiomyoplasty 90% of surviving patients had class I or II symptoms and 10% had class III symptoms. However, in the medical treatment group 27% of surviving patients had class I or II symptoms and 67% had class III or IV symptoms. In the cardiomyoplasty group left ventricular ejection fraction increased from 20% +/- 3% to 24.4% +/- 6.3% at 6 months (p < 0.05). In the heart transplantation group the left ventricular ejection fraction normalized, and the mean value of the left ventricular ejection fraction did not change in the medical treatment group. The need for endomyocardial biopsy and the incidence of rejection and infection were characteristics of the heart transplantation group. CONCLUSIONS: In properly selected patients, cardiomyoplasty and heart transplantation seem to be associated with improvement in survival and functional class at mid-term follow-up. Heart transplantation was more effective than cardiomyoplasty for functional class improvement.

Adult↗
PubMed1995

Peak oxygen consumption and resting left ventricular ejection fraction changes after cardiomyoplasty at 6-month follow-up.

BACKGROUND: The effects of cardiomyoplasty on cardiopulmonary exercise test characteristics are not fully known. METHODS AND RESULTS: We determined in 19 patients who underwent cardiomyoplasty for treatment of refractory heart failure (New York Heart Association [NYHA] functional class III) before (pre) and at 6-month follow-up (post) maximum oxygen consumption (peak VO2), NYHA functional class, and resting left ventricular ejection fraction (LVEF) (MUGA). We analyzed the results according to pre peak VO2 < or > 14 mL/kg per minute and the correlation between the changes in absolute values of LVEF and peak VO2. Pre- and post-peak VO2 values were 15.9 +/- 4.4 and 18.6 +/- 6.4 mL/kg per minute, respectively (P = .059). In the subgroup with pre-peak VO2 < 14 mL/kg per minute, the peak VO2 increased from 11.1 +/- 1.9 to 16.4 +/- 6.2 mL/kg per minute (P = .02). The subgroup with peak VO2 > 14 mL/kg per minute showed pre- and post-peak VO2 of 19.2 +/- 2.6 and of 20.1 +/- 7 mL/kg per minute, respectively (P = .06). The pre-total exercise time of the entire group increased from 688.4 +/- 222.1 to 833.7 +/- 241.6 seconds (P < .04). For the subgroup with preoperative peak VO2 < 14 mL/kg per minute, exercise time improved from 585 +/- 76.9 to 825 +/- 186.3 seconds (P < .01). In the subgroup with preoperative VO2 > 14 mL/kg per minute, the preexercise and postexercise time was 763.6 +/- 264.4 and 840 +/- 282 seconds, respectively (P = .4). Pre-LVEF increased from 20.6 +/- 3.3% to 24.2 +/- 7.8% at 6 months of follow-up (P = .02). At 6 months of follow-up, 9 patients were in NYHA functional class I and 10 were in class II. There was no correlation between LVEF values and absolute values of peak VO2 before (r = .123, P = .6) and after (r = .27, P = .2) cardiomyoplasty. A weak correlation was observed between the changes in absolute values of peak VO2 and LVEF from the preoperative to the postoperative period (r = .48, P = .048). CONCLUSIONS: Cardiomyoplasty is a useful method for improving NYHA functional class and LVEF in patients with heart failure. Peak VO2 < 14 mL/kg per minute before cardiomyoplasty may be a selection criterion with which to determine improved exercise capacity after surgery. The effects of cardiomyoplasty on LVEF appear to be partially associated with maximum exercise capacity changes.

Adult↗
PubMed1995

Clinical and left ventricular function outcomes up to five years after dynamic cardiomyoplasty.

Improvement in congestive heart failure and left ventricular function after dynamic cardiomyoplasty has been reported in patients with severe cardiomyopathies, but the long-term effects of this procedure remain unclear. In this investigation 31 patients undergoing cardiomyoplasty for treatment of idiopathic dilated cardiomyopathy were annually investigated with radionuclide scintigraphy, Doppler echocardiography, and right-sided heart catheterization. They were in New York Heart Association functional class III or IV before the operation. No hospital deaths occurred, but one patient with progressive heart failure required urgent heart transplantation 42 days after cardiomyoplasty. The other patients were followed up from 6 to 70 months (mean 25.6 months) and 12 patients died at late follow-up. Actuarial survivals were 86% at 1 year, 61.4% at 2 years, and 42.5% at 3 to 5 years of follow-up. Multivariate analysis of factors influencing outcome showed that long-term survival was significantly affected by preoperative functional class and pulmonary vascular resistance. Functional class improved from 3.2 +/- 0.4 to 1.7 +/- 0.7 in the surviving patients (p < 0.01). Furthermore, left ventricular ejection fraction improved from 19.8% +/- 3% to 23.9% +/- 7.2% (p < 0.01), and significant changes in stroke index, arterial pressure, pulmonary wedge pressure, and left ventricular stroke work index were also found at 6 months of follow-up. In the late postoperative period, the left ventricular ejection fraction tended to decrease and returned to preoperative levels at 5 years, whereas hemodynamic variables did not change significantly. Thus, despite the tendency of the left ventricular ejection fraction to decrease at late follow-up, the long-term course of these patients seems to be characterized by the maintenance of hemodynamic improvement. However, long-term survival after cardiomyoplasty is limited by the severity of the patient's condition before the operation.

Actuarial Analysis↗
PubMed1995

Present trends in clinical experience with dynamic cardiomyoplasty.

Dynamic cardiomyoplasty has been performed to reinforce the myocardium in the treatment of patients with severe cardiomyopathies. At the Heart Institute of São Paulo University Medical School, 36 patients were submitted to cardiomyoplasty between May 1988 and December 1993. The indications were idiopathic dilated cardiomyopathy in 31, ischemic cardiomyopathy in 3, and Chagas' disease cardiomyopathy in 2 patients. Twenty-eight patients were categorized in New York Heart Association (NYHA) Class III and 8 in Class IV despite the use of maximal medical therapy. There were no hospital deaths, and patients were followed up from 2 to 70 months (mean, 24 months). Besides the improvement of NYHA functional class from 3.2 +/- 0.6 to 1.6 +/- 0.9 at 6 months of follow-up, patients also presented significant changes in the left ventricular systolic and diastolic functions. Nevertheless, 16 patients died, and 2 patients were submitted to heart transplantation during late follow-up. Actuarial survival rates were 82.3% at 1 year, 61.5% at 2 years, and 38.8% at 5 years of follow-up. Otherwise, the analysis of factors influencing the outcome showed that long-term survival was significantly affected by preoperative functional class and by pulmonary vascular resistance. The 26 patients operated in NYHA functional Class III and with pulmonary vascular resistance below 4 Wood units presented survival rates of 72.7% at 2 years and of 63% at 5 years of follow-up. In conclusion dynamic cardiomyoplasty improves functional class and left ventricular function in patients with severe cardiomyopathies. However, the long-term survival after this surgical procedure may be limited by the patients' condition before the operation.

Adolescent↗
PubMed1995

Respiratory system, lung, and chest wall mechanics after longitudinal laparotomy in rats.

It has been demonstrated that respiratory resistance and elastance increase whilst the abdomen remains open during longitudinal laparotomy. We wished to determine whether changes also occur after abdominal closure in the same animal preparation. In 10 sedated, anaesthetized paralysed, and mechanically-ventilated rats (309 +/- 33 (SD) g), resistances and elastances of the respiratory system, lung, and chest wall were measured both before longitudinal laparotomy and directly after abdominal closure. Furthermore, the resistances were also split into their initial and difference components, the former reflecting the Newtonian resistances and the latter representing the viscoelastic/inhomogeneous pressure dissipations in the system. For this purpose, the end inflation occlusion during constant inspiratory flow method was used. After laparotomy, no statistically significant changes were found in elastances and resistances of the respiratory system, lungs and chest wall (paired Student's t-test, significance level = 5%). It can be concluded that after midline xiphipubic laparotomy accompanied by bilateral ventro-dorsal infracostal incision, respiratory resistances and elastances were not different from those found in the control condition.

Animals↗
PubMed1995

Endoscopic mucosal resection for superficial carcinoma and high-grade dysplasia of the esophagus.

Endoscopic mucosal resection (EMR) is a recently introduced therapeutic method based on the principles of the strip biopsy for resection of flat lesions of the gastrointestinal tract. Eleven asymptomatic patients (nine men, two women) with superficial carcinoma or high-grade dysplasia of the intrathoracic esophagus were treated by EMR during a 6-month period. The patients' mean age was 64 years (range, 49-78). The site of the lesions was the middle third of the esophagus in eight, upper third in two, and lower third in one patient. All patients in this series had a flat (II) type of superficial cancer. The procedure was carried out in all 11 patients without complication. Histopathological examination of the specimens revealed squamous cell carcinoma in nine patients. The remaining two patients were confirmed to have dysplasia only. Free margins measured greater than 5 mm in all cases. No recurrence was detected in a mean follow-up of 8 (5-10) months. For superficial flat lesions, EMR proved to be a safe and curative procedure that provided good quality of life following resection. However, larger trials are needed to confirm these results. Applying EMR to esophageal dysplasia could decrease the incidence of esophageal cancer.

Aged↗
PubMed1995

[Evaluation of chronic morphological changes in the latissimus dorsi, after cardiomyoplasty, with magnetic resonance].

PURPOSE: Long term clinical and hemodynamic benefits of dynamic cardiomyoplasty (DC) have been reported. However, no information is available about long-term morphological changes in the wrapped latissimus dorsi (LD) muscle in humans. METHODS: The latissimus dorsi muscle flap was evaluated by magnetic resonance imaging (MRI) in 5 patients submitted to DC for treatment of severe dilated cardiomyopathy. All patients were studied from 24 to 52 months after the surgical procedure at the time of the cardiomyostimulator replacement. In the interim, LD was stimulated with burst of 6 pulses (burst duration 185 msec, burst freq 30Hz) synchronized to every cardiac contraction with a maximum of 100 LD contractions/min. Images were acquired on a GE Sigma 1.5 T system (TE = 25ms, TR = R- Rx2, slice thickness 8mm). RESULTS: The thickness of was 7.6 +/- 0.8mm. In addition, the signal intensity of the LD was compared with that of thoracic skeletal muscle and was found to be increased (2.19 +/- 0.42). The signal intensity was similar to that of subcutaneous fat in those images. CONCLUSION: Morphologic changes in the wrapped LD muscle consistent with fatty degeneration occur after DC and can be detected by MRI. Further studies will be necessary to demonstrate the clinical significance of such LD muscle flap changes.

Adult↗
PubMed1994

Lateral lymph node dissection for rectal carcinoma below the peritoneal reflection.

Lateral lymph node dissection has been advocated for advanced low rectal tumours. However, its benefit is debatable because of the possibility of postoperative bladder and sexual impairment. To assess the role of lateral lymph node dissection 95 patients who underwent the procedure between 1981 and 1991 were reviewed and compared with 83 who had resection of rectal cancer without lateral node dissection. Only ten (11 per cent) of the 95 patients had lateral lymph node involvement; all had Dukes' C tumours. Lymphovascular invasion was present in 50.6 per cent of all patients and neural invasion in 27 per cent of 65 examined specimens. Local recurrence, distant metastasis and overall 5-year survival rates were 7, 9 and 76 per cent respectively in patients undergoing extended lymphadenectomy and 16, 7 and 72 per cent respectively in those who had resection alone. There were no statistically significant differences in survival between the two groups for any Dukes' stage. Recurrence, metastasis and survival were related more to venous or neural invasion and tumour spread than to node dissection. These results demonstrate that patients with Dukes' A tumours do not benefit from lateral lymph node dissection, and that local recurrence rates in those with Dukes' B and C lesions are not significantly decreased. It is concluded that extended lymphadenectomy is unlikely to provide significant benefit to patients with low rectal cancer.

Adenocarcinoma↗