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Biomedical subjects

A C Carvalho

Publications and source records attributed to A C Carvalho.

At least 37 records · Page 2Linked to original sources
PubMed2000

Multiple arterial anomalies in the newborn infant. Echocardiographic and angiographic diagnosis.

Multiple arterial anomalies characterized by tortuosity and rolling of the pulmonary arteries and aorta were diagnosed on echocardiography in an asymptomatic newborn infant with a phenotype suggesting Ehlers-Danlos syndrome. These changes were later confirmed on angiography, which also showed peripheral vascular abnormalities. The electrocardiogram showed a probable hemiblock of the left anterosuperior branch, and the chest x-ray showed an excavated pulmonary trunk with normal pulmonary flow.

Abnormalities, Multiple↗
PubMed2000

Gap junctions in the cardiovascular and immune systems.

Gap junctions are clusters of intercellular channels directly connecting the cytoplasm of adjacent cells. These channels are formed by proteins named connexins and are present in all metazoan organisms where they serve diverse functions ranging from control of cell growth and differentiation to electric conduction in excitable tissues. In this overview we describe the presence of connexins in the cardiovascular and lympho-hematopoietic systems giving the reader a summary of the topics to be covered throughout this edition and a historical perspective of the discovery of gap junctions in the immune system.

Animals↗
PubMed2000

Gap junction modulation by extracellular signaling molecules: the thymus model.

Gap junctions are intercellular channels which connect adjacent cells and allow direct exchange of molecules of low molecular weight between them. Such a communication has been described as fundamental in many systems due to its importance in coordination, proliferation and differentiation. Recently, it has been shown that gap junctional intercellular communication (GJIC) can be modulated by several extracellular soluble factors such as classical hormones, neurotransmitters, interleukins, growth factors and some paracrine substances. Herein, we discuss some aspects of the general modulation of GJIC by extracellular messenger molecules and more particularly the regulation of such communication in the thymus gland. Additionally, we discuss recent data concerning the study of different neuropeptides and hormones in the modulation of GJIC in thymic epithelial cells. We also suggest that the thymus may be viewed as a model to study the modulation of gap junction communication by different extracellular messengers involved in non-classical circuits, since this organ is under bidirectional neuroimmunoendocrine control.

Bone Marrow Cells↗
PubMed2000

The value of echocardiography in the diagnosis and followup of rheumatic carditis in children and adolescents: a 2 year prospective study.

OBJECTIVE: To evaluate echocardiographic/Doppler findings in patients with rheumatic fever whether or not clinical manifestations of carditis were present, and the followup of these findings 24 months after the acute phase. METHODS: Twenty-two patients with rheumatic fever (13 boys, 9 girls, mean age 11.0 years) were evaluated at baseline (at diagnosis) and after 3 and 6 mo of disease. Eighteen patients were reevaluated 24 mo later. The assessment included physical and cardiac examination, electrocardiogram, chest radiography, and color ECHO/Doppler performed blindly by different investigators. The control group included 15 healthy children. RESULTS: We observed clinical carditis in 8 patients (36.4%): Group 1, all with ECHO abnormalities. We observed no clinical cardiac manifestations in 14 patients (Group 2), but 5 (35.7%) had positive ECHO/Doppler abnormalities that persisted at least 6 mo in followup assessments. Mitral and aortic were the most frequently involved valves. In Group 1 we observed normalization of the ECHO/Doppler in 3 patients, improvement in 2, no change in 2, and worsening in one. Twelve of 14 patients without clinical carditis were reevaluated, including the 5 patients with ECHO/Doppler abnormalities during the initial evaluations; normalization or improvement was observed in 2 patients, no change in 2, and worsening in one. We observed no ECHO/Doppler abnormalities in the control group. CONCLUSION: This blind prospective study suggests the existence of asymptomatic carditis in some patients with rheumatic fever and the role ECHO/Doppler investigation could play in diagnosis and followup.

Adolescent↗
PubMed1999

Cholinergic stimulation with pyridostigmine blunts the cardiac responses to mental stress.

Mental stress may induce myocardial ischemia and ventricular arrhythmia in patients with coronary artery disease, and cholinergic stimulation is a potential protective mechanism. The purpose of this study was to determine the effect of pyridostigmine bromide (PYR), a reversible cholinesterase inhibitor, on the cardiac responses to a mental stress challenge. Twelve healthy young volunteers were submitted to a mental stress test (arithmetic test) 2 hours after the oral administration of either placebo or PYR (45 mg) on two separate days, following a randomized crossover double-blind protocol. Heart rate was reduced after both placebo and PYR (p < 0.05), but the cardiac responses to the mental stress were lower with PYR (p < 0.05): mean RR interval (mean +/- SE)-placebo: 730 +/- 19 msec; PYR: 769 +/- 21 msec; Peak systolic pressure-placebo: 129 +/- 4 mmHg; PYR: 124 +/- 3 mmHg; Peak diastolic pressure-placebo: 92 +/- 3 mmHg; PYR: 89 +/- 4 mmHg; Mean rate-pressure product-placebo: 10,496 +/- 412 bpm x mmHg; PYR: 9,746 +/- 383 bpm x mmHg. In conclusion, 45 mg of pyridostigmine blunted the pressor and chronotropic responses to mental stress in healthy young subjects.

Aged↗
PubMed1999

Safety of dobutamine-atropine stress echocardiography: A prospective experience of 4,033 consecutive studies.

Dobutamine-atropine stress echocardiography (DASE) is an established method and has been shown to be accurate for the detection of coronary artery disease. Still, there are few large clinical studies that analyze the safety of DASE in general or the safety of performing it on an ambulatory basis. Most studies use a target heart rate as the primary end point regardless of whether asymptomatic ischemia occurs. Such studies have shown a serious cardiac event rate of approximately 0.3%. We prospectively studied 4,033 consecutive patients on an ambulatory basis and in the hospital with the use of DASE from July 1991 to December 1998. All tests were performed by an experienced physician, and all clinical and DASE data were stored in a large database organized at the beginning of the study. Dobutamine was infused in scalar doses of 5, 10, 20, 30, and 40 microg/kg per minute in 3-minute stages. Development of a new wall motion abnormality, achievement of 85% of target heart, and end of the DASE infusion protocol were used as an end point. If 85% of the target heart rate was not achieved, atropine was infused up to 1 mg in the absence of myocardial ischemia, which was used in 1,280 studies. There were 3,645 diagnostic tests, and 388 (10%) were found to be nondiagnostic. This result was due to poor image quality in 115 (3%), end of protocol in negative-submaximal examinations in 124 (3%), and limiting side effects in 149 (4%). Thirty-seven percent of the tests showed positive results for myocardial ischemia. Major test-related cardiac complications occurred in 10 (0.25%) patients and included 1 ventricular fibrillation, 1 case of myocardial infarction, and 8 cases of sustained ventricular tachycardia. Atropine poisoning was observed in 5 (0.12%) patients. No deaths occurred as a direct or indirect consequence of DASE. We conclude that dobutamine-atropine stress echocardiography is a reasonably safe method for detection of coronary artery disease in the hospital or in an ambulatory basis. The use of new wall motion abnormality as 1 of the end points may prevent further ischemia-related complications.

Adolescent↗
PubMed1998

Replacement of infected thoracic aortic prosthesis with a spiral composite vein graft.

We describe a case of a patient who had a ruptured aorta repaired by femorofemoral bypass with an interposition graft and subsequently had a graft infection. The patient was taken to operation and the old graft was removed. It was replaced by a spiral great saphenous vein graft. The patient has been followed up for 36 months with computed tomographic scanning, which has shown that the vein graft has not dilated.

Acinetobacter Infections↗
PubMed1998

Endoscopic placement of stents in aneurysms of the descending thoracic aorta.

This is a case of a patient with two saccular aneurysms in the descending aorta. Two self-expanding stents were inserted through an opening in the aortic arch, guided by the use of an Olympus endoscope, under profound hypothermia and total circulatory arrest. The bloodless field made possible the identification of the main thoracic branches, facilitating the positioning and deployment of both stents. Immediate postoperative recovery was excellent.

Aged↗
PubMed1998

Importance of intraoperative transesophageal echocardiography during coronary artery surgery without cardiopulmonary bypass.

The goal of this study was to assess left ventricular segmental wall motion (SWM) abnormalities during coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB), and its impact on the immediate postoperative outcome. Transesophageal echocardiography was used intraoperatively in 27 patients (mean age 57 years) who had CABG without CPB. Images obtained with a 5-MHz biplane transesophageal echocardiographic probe in the transgastric and transesophageal planes were recorded before, during, and after 48 coronary artery clampings for saphenous vein or internal mammary artery anastomosis. Transthoracic echocardiography was performed 1 day before surgery and on the seventh postoperative day. During the 48 coronary artery clampings, 31 (64%) new SWM abnormalities were found. At the time of chest closure, complete recovery occurred in 16 (50%) segments, partial recovery in 10 (33%), and no recovery in 5 (17%). On the seventh postoperative day the new SWM abnormalities persisted in all 5 segments without recovery at the end of the surgery and in 2 of 10 (20%)segments with partial recovery (group 1). Group 1 had higher variation on the echocardiographic point score index between the beginning and end of surgery, higher enzymatic levels, more ST-T changes on the electrocardiogram, and more clinical problems than group 2 (patients without new SWM abnormalities on the seventh postoperative day) (P < .05). We concluded that new SWM abnormalities of the left ventricle occur during CABG without CPB as assessed by intraoperative transesophageal echocardiography. Persistence of these abnormalities at the end of surgery may be a predictor of SWM dysfunction and clinical problems in the immediate postoperative period.

Adult↗
PubMed1998

[Cardiorespiratory response during exercise in heart transplant recipients. Comparative ergoespirometric analysis with normal health subjects].

PURPOSE: To evaluate the cardiorespiratory response of heart transplant (HT) recipients. METHODS: Nine HT recipients (GI) underwent ergospirometric tests and were compared to 9 apparently healthy, sedentary subjects with similar sex, age, weight and height (GII). All were male patients aging 48 +/- 12 years, in functional class I (NYHA) an average of 23 +/- 21 months after HT. They were receiving cyclosporin, azathioprine, prednisone, dipyridamole and antihypertensive drugs. The tests were symptom-limited and they were interrupted due to exhaustion. RESULTS: During peak exercise, GI had a significantly lower physical performance related to lower VO2, VE, VEO2, HR, endurance time and work load. At the anaerobic threshold, VO2, endurance time and work load levels were also significantly lower in GI. The physical performance was similar between the groups in the 40W load. CONCLUSION: The cardiorespiratory performance in GI was significantly lower at peak exercise and similar to GII in the 40W load, showing the HT benefits cardiac patients during usual activities.

Exercise Test↗
PubMed1998

[Hemostatic changes in children treated with heart surgery with cardiopulmonary bypass].

PURPOSE: We evaluated hemostasic changes in children undergoing open heart surgery with cardiopulmonary bypass (CPB). METHODS: We studied 17 children before, during surgery, in the immediate, first and between the 4th and 7th postoperative days, measuring hematocrit, prothrombin time, activated partial thromboplastin time, fibrinogen, platelet count, factor V and euglobulin lysis time. Children were divided in those with and without excessive bleeding in the postoperative period. RESULTS: We observed significant prolongation of prothrombin time and activated partial thromboplastin time, reduction of fibrinogen and factor V, and shortening of euglobulin lysis time. Six (35%) children bled excessively. Platelet count reduction was greater in the intra operative period in these cases and the duration of CPB was longer in this group. CONCLUSION: Changes in hemostasis during open heart surgery are due to coagulation cascade disorders as well as fibrinolysis. The incidence of excessive bleeding is higher in the pediatric group. Prolonged CPB time and greater reduction in platelet count differentiated both groups.

Cardiac Surgical Procedures↗
PubMed1998

[Anomalous origin of the right pulmonary artery from the ascending aorta (Hemitruncus)].

The origin of the right pulmonary artery from the ascending aorta is a rare cogenital anomaly, with very few reports in the literature. We describe two cases of this rare malformation, one of them, associated with interruption of the aortic arch (type B). In both cases, the diagnosis was made by two-dimensional echocardiography, with angiographic confirmation in one of them. The origin of the right pulmonary artery was close to the aortic valve, anomaly pathogenetically distinct from the type that arises close to the innominate artery.

Abnormalities, Multiple↗
PubMed1998

[Right ventricle-dependent coronary circulation in pulmonary atresia with intact ventricular septum. Absence of origin of the coronary arteries from the aorta].

This report describes the clinical, echocardiographic and angiographic aspects of a five-day old boy with pulmonary atresia and intact ventricular septum. Both the echocardiogram and the aortography did not show any coronary arteries arising from the aorta. Two-dimensional echocardiography was able to identify the coronary arteries originating from the right ventricle and so did the right ventricular angiogram. No retrograde flow into the aorta or pulmonary trunk was identified after opacification of the coronary arteries. As far as we know this is the first case diagnosed by echocardiography, and is a vivid example of the necessity of identifying the coronary arteries in patients with pulmonary atresia and intact ventricular septum.

Aorta↗
PubMed1998

[Quantification of mitral prosthesis failure by different methods of evaluation by transesophageal echocardiography].

PURPOSE: To evaluate the different methods for grading mitral regurgitation (MR) by transesophageal echocardiography (TEE) in patients with clinical suspicion of mitral prosthesis dysfunction. METHODS: Cardiac catheterization (Cath) was performed in 15 patients for grading the severity of prosthetic MR, divided in two groups based on the presence or absence of severe MR. Prosthetic MR was quantified by TEE using methods commonly used for MR of native valves: subjective assessment by color Doppler, objective assessment based on absolute jet area and on its relative area (jet area/left atrial area) and assessment based on the presence of systolic flow reversal in pulmonary vein. RESULTS: Prosthetic MR was mostly transprosthetic (14 patients) and eccentric (11 patients). There was significant correlation (p < 0.05) between Cath and TEE for identification of severe MR based on subjective assessment and on the presence of systolic flow reversal in pulmonary vein. Identification based on absolute (jet area > 7 cm2) and relative (jet area > 35% of left atrial area) jet areas did not reveal significant correlation with the angiographic grade and showed clear underestimation by TEE when the last method was used. However, there was good correlation (p < 0.05) if relative jet areas > 30% were considered as cut point. CONCLUSION: TEE correctly identified angiographic severe mitral prosthesis regurgitation, mainly by the presence of systolic flow reversal in pulmonary vein and subjective assessment. The estimation of severity of the prosthetic MR by absolute or relative jet area seems to be limited and should be used with caution due to eccentricity of the regurgitant jet, frequently seen in mitral prosthesis dysfunction.

Adult↗
PubMed1998

[Utilization of self-expandable prosthesis (stent) introduced through the femoral artery for treatment of dissection of the descending aorta].

PURPOSE: We present four cases of dissection of the thoracic descending aorta that underwent treatment with an auto expandable dácron-covered stent. METHODS: The stent was deployed through the femoral artery in the hemodynamic laboratory after sedation, local anesthesia in both inguinal areas and systemic heparinization. The catheter with the stent was introduced through a cutdown in the left femoral artery until the area in the thoracic aorta with the previously diagnosed tear. RESULTS: The stent was expanded with immediate occlusion of the false lumen. The whole procedure took 90 minutes and the patients were discharged without complications. CONCLUSION: Stent utilization is an important step to improve treatment results in type B aortic dissection.

Acute Disease↗
PubMed1998

Vasoplegic syndrome after open heart surgery.

BACKGROUND: A new form of postperfusion manifestation is detailed, a vasoplegic syndrome presenting in the postoperative period after cardiopulmonary bypass (CPB) heart surgery. METHODS: This retrospective study included sixteen patients who underwent cardiovascular surgery using CPB and exhibited clinical and hemodynamic features compatible with vasoplegic syndrome. The technique of CPB was hypothermic (28 degrees C) in 15 and normothermic in 1 patient, and hypothermic blood cardioplegia was employed in all patients, except 1. The mean CPB time was 121 minutes, ranging from 80 to 210 minutes. RESULTS: The patients presented a severe feature comprising hypotension, tachycardia, normal or elevated cardiac output, low systemic vascular resistance and decreased filling pressures. Fluid administration alone was not capable of restoring hemodynamic parameters. Physical examination revealed normal capillary filling at the extremities although oliguria and hypotension were observed. These patients needed a high dosage of vasoconstrictor drugs (norepinephrine) for blood pressure control but even high dose norepinephrine did not produce the classical situation of cool extremities and weak peripheral pulses, with increased morbidity and mortality. Severe systemic complications could develop if the vasoplegic syndrome persisted 36-48 hours after its onset. All patients, except 3, presented associated postoperative complications and 4 patients died. The characteristics of vasoplegic syndrome are similar to those observed in septic shock, where the alterations are mediated by cytokines and tumor necrosis factor-alpha. CONCLUSIONS: The appearance of vasoplegic syndrome augmented operative morbidity with a consequent increased risk to the patient in the early postoperative period.

Adult↗