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Biomedical subjects

M J Antunes

Publications and source records attributed to M J Antunes.

At least 19 recordsLinked to original sources
PubMed2003

Coronary surgery with non-cardioplegic methods in patients with advanced left ventricular dysfunction: immediate and long term results.

OBJECTIVE: To evaluate perioperative results and long term survival in patients with severe left ventricular (LV) dysfunction undergoing coronary artery bypass grafting (CABG) using non-cardioplegic methods. METHODS: From April 1990 through December 1999, 4100 consecutive patients underwent isolated CABG using hypothermic ventricular fibrillation. Of these, 141 (3.4%) had severe LV dysfunction (ejection fraction < 30%). Mean age was 58.3 (9.6) years. 64 patients (45.4%) were in Canadian Cardiovascular Society class III or IV and 16 (11.3%) were subjected to urgent or emergent surgery. A previous myocardial infarction was recorded in 127 (90.1%). The majority (89.4%) had triple vessel and 26 (18.4%) had left main disease. The mean number of grafts per patient was 3.1. At least one internal thoracic artery was used in all patients and 21 (14.8%) had bilateral internal thoracic artery grafts (1.2 arterial grafts per patient). RESULTS: Perioperative mortality was 2.8% (4 patients) and the incidence of acute myocardial infarction 2.8%. 50 (35.5%) patients required inotropes but only 16 (11.3%) required it for longer than 24 hours; 5 patients (3.5%) needed mechanical support. The incidence of renal failure was 3.5%. Mean duration of hospital stay was 9.6 (8.3) days. Follow up was 95% complete and extended for a mean of 57 (30) months. Late mortality was 11.5%. Actuarial survival rates at 1, 3, and 5 years were 96%, 91%, and 86%, respectively. CONCLUSIONS: Non-cardioplegic techniques are safe and effective in preserving the myocardium during CABG in patients with coronary artery disease and poor LV function, with low operative mortality and morbidity, and encouraging medium to long term survival rates.

Blood Vessel Prosthesis Implantation↗
PubMed2001

[Coronary surgery after 70 years of age].

Previous reports on coronary artery bypass grafting in elderly patients have not usually addressed the current era of aggressive percutaneous angioplasty. To investigate this important subgroup of patients, we analyzed our recent coronary artery bypass grafting experience with patients 70 years of age or older from May 1988 to August 1993, 158 consecutive patients in this age range (mean age 70.3 years) underwent surgical revascularization at our institution. Overall operative mortality was 4.4% (7/158), with 71.4% (5/7) of deaths due to cardiac causes. Postoperative morbidity occurred in 50.6% (80/158) of patients but was of a serious nature in only 12.0% (19/158). Surgical priority was significantly correlated with operative mortality: 1.6% (2/122) for elective cases and 17.2% (5/29) for urgent or emergency cases (p < 0.01). Univariate analysis isolated the need for postoperative inotropic support or mechanical assistance, perioperative myocardial infarction and reoperation for bleeding as significant risk factors for operative mortality (p < 0.01). Of the patients discharged from the hospital, 144 (95.4%) were followed up for a mean of 23 months (3-62). During the follow-up period there were 3 deaths, all from non cardiac causes, and 92.3% of the patients were in Canadian Cardiovascular Society class I (CCS). These results indicate that, although with somewhat higher morbidity and mortality rates, elderly patients have a very acceptable operative risk in the current era of high-risk coronary artery bypass grafting, particularly if elective revascularization is possible.

Age Factors↗
PubMed2000

Open mitral commissurotomy: the 'golden standard'.

BACKGROUND AND AIM OF THE STUDY: Percutaneous balloon mitral commissurotomy (PBMC) has recently emerged as an alternative to surgical commissurotomy for the treatment of rheumatic mitral valve stenosis. However, this blind procedure may result in incomplete separation of the commissures, which could lead to accelerated restenosis. Hence, open mitral commissurotomy (OMC), which is a visually oriented procedure, remains our method of choice. This study was aimed at assessing the long-term outcome of the OMC procedure. METHODS: A series of OMC performed between 1988 and 1991, involving 100 mitral valves, each with a preoperative echocardiographic score < or =10 was investigated clinically and by echocardiography. RESULTS: Postoperatively, the mean valve area achieved was 2.89+/-0.49 cm2, compared with a mean preoperative value of 0.99+/-0.23 cm2. In a recent follow up, conducted after a mean of 8.5 years (range: 7-11 years), the mean valve area measured by echo-Doppler in this patient group was 2.37+/-0.42 cm2 (range: 1.6 - 3.6 cm2), and 81% of patients had a valve area >2.0 cm2. Reoperation was required in only two cases. The late mortality rate was 4% (0.5%/pt-yr), and was in no case valve-related. Two-thirds of the patients had no or only mild mitral insufficiency, and 93% were in NYHA functional class I or II. The nine-year actuarial survival rate was 96%, freedom from reoperation 98%, and freedom from all valve-related complications 92%. Complementary to this experience, during the past 10 years we have performed modified OMC in 919 (79%) of all 1,151 patients with mitral stenosis submitted for surgery, including 257 with mixed disease. The mean post-commissurotomy valve area (2.9 cm2) was identical to that of the study group. Moderate to severe valve calcification was not an absolute contraindication to valve conservation. CONCLUSION: OMC remains the best alternative for the treatment of all cases of mitral stenosis, independently of the degree of pliability. In our experience, the medium- and long-term results are significantly better than those usually reported in PBMC series.

Catheterization↗
PubMed2000

[Role of surgery in the treatment of severe congestive heart failure].

Patients with severe congestive heart failure which is not reversible by therapy and caused by mechanical abnormalities that are not surgically correctable, generally constitute desperate cases in which surgical intervention is only palliative. Currently, only transplantation can be considered an adequate mid-term therapy, while cardiomyoplasty and ventricular reduction (Batista) have not evolved as viable alternatives. The former has not yielded satisfactory results and the experience with the latter is still too short, although the short term results also appear discouraging. The shortage of available organs for the number of patients on the waiting list and the rejection and infection phenomena, which remain the main difficulties with transplantation, may be overcome in the not too distant future. Finally, the artificial heart will almost certainly be an alternative, but it may, eventually, be overthrown by xenotransplantation.

Cardiomyoplasty↗
PubMed1999

Non-cardioplegic coronary surgery in patients with severe left ventricular dysfunction.

OBJECTIVES: Although most surgeons use cardioplegia for myocardial protection during coronary artery bypass grafting (CABG), some still use non-cardioplegic methods with very good early and long-term outcome. However, the results in patients with severe left ventricular dysfunction remain unproved. This study evaluates the perioperative mortality and morbidity in patients with severe left ventricular dysfunction submitted to CABG using non-cardioplegic methods. METHODS: From April 1990 through December 1997, 3,180 patients were consecutively subjected to isolated CABG using non-cardioplegic methods, for construction of the distal anastomoses. This prospective study is based on the 107 (3.4%) patients with severe impairment of the left ventricular function (ejection fraction < 30%). The mean age at operation was 57.0 +/- 9.2 years and 95.3% of patients were male. Fifty three patients (49.5%) were in class CCS III/IV and 12 (11.2%) were subjected to urgent surgery. A history of previous myocardial infarction was recorded in 99 (92.5%) patients. Ninety seven (90.6%) patients had triple vessel and 17 (15.9%) left main stem disease, and 77 (71.9%) had a left ventricular end-diastolic pressure > 20 mmHg. Cardiopulmonary bypass time was 73.1 +/- 21.7 min. The mean number of grafts per patient was 3.2. At least one internal mammary artery was used in all cases and 16 patients (14.9%) had bilateral internal mammary artery grafts (1.2 arterial grafts/patient). Endarterectomies were performed in 23 (21.5%) patients. RESULTS: Perioperative mortality was 2.8% (respiratory-1; cardiac-2). Forty one (38.3%) patients required inotropes, but for longer than 24 h in only 12 (11.2%), and two (1.9%) needed intra-aortic counterpulsation. The incidence of myocardial infarction was 2.8%. Two (1.9%) patients had reintervention for haemorrhage and another five (4.6%) for sternal complications. The incidences of supraventricular arrhythmias, renal failure and cerebrovascular accident were 16.8%, 3.6% and 2.8%, respectively. The mean time of hospital stay was 9.3 +/- 6.4 days. CONCLUSION: These results appear to demonstrate that non-cardioplegic methods afford good myocardial protection and operating conditions with excellent applicability, even in patients with severe left ventricular dysfunction.

Aged↗
PubMed1999

[Effect of pedagogic methods on planning of nursing education: bibliographic review].

This paper looks historically and critically at the pedagogical and conceptual models using by nurses during five cycles of Brazilian History in nursing education. This article examines the patterns of nursing education while this historical time and suggests to include pedagogic models based on problem solving in nursing health practice.

Brazil↗
PubMed1999

[Mitral valve surgery in elderly patients].

The increase in life expectancy results in a larger number of elderly patients with mitral valve pathology requiring surgical correction. Generally speaking, the indications for surgery are identical to those which apply to other age groups, but the greater incidence of mortality and, especially, of morbility make a degree of selectivity advisable. More than with any group, it is important to consider the risk: benefit ratio. However, in the majority of cases, it is possible to optimise the clinical condition of the patients with a significant decrease in risk. One of the most controversial aspects is that of the advantages or disadvantages of mitral valvuloplasty vs. prosthetic replacement. Although the eventual lower durability of the valvuloplasty might be considered a contraindication, because of the risk of reintervention at a later age, I believe that valvuloplasty is also preferable in elderly patients. This is confirmed by the well known fact that mitral valvuloplasty for myxomatous mitral regurgitation, prevailing in this age group, has the most durable results among all types of pathology. In the last 10 years, 433 patients above 70 years of age (11.6% of the total) were subjected to valvular surgery in Coimbra. Valvuloplasty was possible in more than 90% of the cases of mitral valve surgery. The mortality was only 2.6%, but significantly higher than that observed in younger patients (0.8%). In conclusion, mitral valve surgery in elderly patients is feasible with acceptable mortality and morbidity, but pre-operative optimization of the patients is essential.

Aged↗
PubMed1999

Aortic valve replacement with small-sized disc prostheses (medtronic hall).

BACKGROUND AND AIM OF THE STUDY: Several studies have demonstrated a worse performance of small prostheses in the narrow aortic root. However, modern low-profile mechanical prostheses have improved hemodynamic performance, are easy to implant, and have been used increasingly in elderly patients, where narrow roots are most frequently observed. We describe our experience in patients with aortic annuli >21 mm with the use of Medtronic Hall prostheses. METHODS: Between April 1988 and December 1997, a total of 332 patients (218 females, 114 males; mean age 59.3 +/- 9.8 years (range: 29-75 years) received Medtronic Hall size 20 (n = 140), 21 (n = 96) or 22 (n = 96) prostheses. The mean body surface area was 1.59 +/-0.12 m2 (range: 1.27-2.01 m2); 140 patients were in NYHA functional classes III/IV. There were no significant differences in clinical characteristics of patients in the three prosthesis-size groups. RESULTS: The mean preoperative systolic left ventricular/aorta gradient was 64.5 +/- 24.8 mmHg (no significant inter-group difference). After cardiopulmonary bypass, peak gradients through the aortic prostheses were 13.9 +/- 8.0 mmHg in size 20 valves, 14.0 +/- 8.1 mmHg in size 21, and 10.1 +/- 8.9 mmHg in size 22. Four patients died in hospital (mortality rate 1.2%); there were no significant inter-group differences in hospital morbidity. Follow up was complete for 97% of the patients (mean 4.3 years; range: 1-11 years). The late mortality rate was 9.3% (n = 31; 2.56% per pt-yr); of these patients, 20 (14.3%) had size 20 prostheses, seven (7.3%) size 21, and four (4.2%) size 22 (p = 0.01). Fourteen patients (4.2%) died from cardiac causes, and six (1.8%) from prosthesis-related causes. Preoperative older age and aortic regurgitation were the only independent predictors of late mortality. Eight patients had systemic thromboembolic events (0.66% per pt-yr), two had prosthetic thrombosis (0.17% per pt-yr) and five had hemorrhagic episodes (0.41% per pt-yr). Seven patients had prosthetic valve endocarditis (0.58% per pt-yr). Among survivors, 97% are currently in NYHA class I/II. CONCLUSIONS: The small (size 20, 21 and 22) Medtronic Hall prostheses have good hemodynamic performance and are an excellent option as valve substitutes in patients with narrow aortic roots.

Adult↗
PubMed1997

Pulmonary sequelae in infants treated with extracorporeal membrane oxygenation.

The decision to place an infant on extracorporeal membrane oxygenation (ECMO) is based on predictions of expected morbidity and mortality. One unknown factor is the relationship between pre-ECMO pulmonary dysfunction and on barotrauma and post-ECMO pulmonary sequelae. To determine whether placement of infants on extracorporeal membrane oxygenation (ECMO) early is associated with less subsequent pulmonary dysfunction than placing infants on EMCO later, we evaluated pulmonary function in 25 neonates prior to ECMO, when the infants had come off EMCO, and at the time of nursery discharge. Pulmonary resistance (R) and compliance (CL) were determined by a pneumotachograph and esophageal manometry, and functional residual capacity (FRC) was determined by a helium dilution method. Maximal expiratory flow (VmaxFRC) was determined by thoracic compression at the time of discharge. Infants were assigned to an early ECMO group (< 36 hours of age, n = 12), or a late ECMO group (> 36 hours of age, n = 13). When first evaluated, the early group had a higher oxygenation index than the late group (mean value, 63 versus 48), but initial pulmonary function measurements were not different between the two groups. In the early group mean CL increase from 0.20 to 0.36 ml/cmH2O/kg, FRC increased from 7 to 20 ml/kg, and mean R decreased from 107 to 61 cmH2O/L/sec between the initial study and immediately after ECMO. In the late group, only FRC increased from a mean of 8 to 20 ml/kg. CL and FRC increased from post-ECMO to discharge in both groups (mean CL from 0.36 to 0.76 ml/cmH2O/kg in the early group, and from 0.30 to 0.79 in the late group). Mean FRC increased from 20 to 26 ml/kg in the early group, and from 20 to 25 ml/kg in the late group. VmaxFRC was lower in the late than the early group at discharge (mean, 1.14 versus 1.58 L/sec; P < 0.05). While both groups of infants had minimal pulmonary dysfunction at discharge, the infants placed on ECMO early had evidence of slightly less airway dysfunction despite a higher initial oxygenation index than the infants placed on ECMO late.

Airway Resistance↗
PubMed1997

Surgery of chest wall deformities.

OBJECTIVE: To evaluate the medium-term results of 77 surgical corrections in patients with chest wall deformities, 53 (68.8%) with pectus excavatum and 24 with pectus carinatum, operated upon from 1985 to 1994. METHODS: The mean age of the patients was 14.7 years (4-39 years) and 77% were younger than 15 years of age. There were 59 male (76.7%) and 18 female patients. Only four had a family history of the malformation. Seven patients (9.1%) presented with asthma-like symptoms, and 13 (16.9%) referred dyspnea and tiredness for small efforts. The remainder (74.2%) were asymptomatic, but most were psychologically disturbed by the deformity and postural abnormality. Two patients had other skeletal abnormalities. The modified surgical technique used in all cases consisted of subperichondrial resection of the abnormal costal cartilages, transverse and longitudinal osteotomies of the sternum and internal stabilization with a steel rod which was generally removed between 6 and 12 months postoperatively. RESULTS: There was neither early nor late mortality. One patient had a pneumothorax which required chest tube drainage. The mean admission time was 10.5 days (8-14 days). Follow-up was complete, and 90% of the patients had increased effort tolerance. Five of the seven patients (72%) with 'asthmatic' symptoms showed a decrease in the frequency of the crises. Two patients had recurrence of the depression by 3 and 8 months, respectively. The remaining 75 patients (97.3%) were satisfied with the cosmetic result of the surgery. CONCLUSIONS: Surgical treatment of chest wall deformities using this technique leads to good cosmetic, orthopedic and psychological results. We believe that the operations should be performed at any age in patients who have at least a moderate deformity.

Adolescent↗
PubMed1997

Mediastinitis after aorto-coronary bypass surgery.

OBJECTIVES: To identify risk factors in 60 cases of mediastinitis amongst 2512 patients (2.3%) subjected to isolated coronary bypass surgery from March 1988 through December 1995, treated by a closed irrigation/drainage system. PATIENTS AND METHODS: The mean age of the 60 patients was 56.9 +/- 6.8 years (45-81 years) and 55 (91.6%) were male. Early mediastinal reexploration was performed in all cases immediately after the diagnosis of mediastinitis, with debridement of necrosed tissues, followed by implantation of a closed-circuit irrigation system of the mediastinum constituted by irrigation catheter and drain, closure of the sternum and skin, and specific systemic antibiotic therapy. The mean interval between the original surgery and reexploration was 9.4 days (range 6-14 days). No patient required more extensive procedures, namely omental or muscular flaps. Twenty potential risk factors in patients with mediastinitis, including diabetes mellitus, obesity, coexistence of peripheral vascular disease, decreased LV function, use of inotropes, mediastinal blood drainage and utilization of double IMA, were compared with the group without mediastinitis. RESULTS: Mean cardiopulmonary bypass time was 74.1 +/- 8.1 min, anesthetic time 3.5 +/- 0.8 h and postoperative mechanical ventilation 18 +/- 3 h. A total of 23 patients (38.3%) received one IMA and 35 (58.3%) two IMAs. In the postoperative period, 7 of the 60 patients (11.6%) had required inotropes because of low output. Mediastinal blood loss was 1112cc +/- 452cc and 9 patients (15%) were transfused. Cultures were positive in 40 cases (66.6%) and the most frequent infecting agent was the Staph. epidermidis in 25 cases (62.5%), followed by Candida albicans and Enterobacter and Serratia species (7.5% each); 1 patient (1.7%) died and 9 (15%) had renal failure. The irrigation/drainage was maintained for a mean of 9.1 days (5-83 days). Patients with mediastinitis had a significantly higher prevalence of diabetes (41.6% vs. 18.8%; P < 0.01), obesity (48.3% vs. 15.2%; P < 0.001), peripheral vascular disease (11.6% vs. 4.0%; P < 0.05), but a lower incidence of poor LV function (18.3% vs. 32.7%; P < 0.05). A double IMA was used more frequently in patients who had mediastinitis (58.3% vs. 23.5%; P < 0.001) CONCLUSIONS: Diabetes mellitus, obesity, co-existence of peripheral vascular disease and use of double IMA are risk factors for mediastinitis after coronary artery surgery. The efficacy of the closed method of treatment with a mediastinal irrigation/drainage system was increased with early diagnosis and reintervention.

Aged↗
PubMed1997

Exudative lung injury is associated with decreased levels of surfactant proteins in a rat model of meconium aspiration.

OBJECTIVE: Meconium aspiration syndrome remains a common cause of respiratory failure in neonates. The acute effects of meconium aspiration are inactivation of lung surfactant in vivo and in vitro. This study investigated the delayed effects of meconium on alveolar surfactant phospholipids and protein levels in spontaneously breathing animals. METHODS: Twenty-two adult rats were given 4.3 mg of dry weight human meconium after endotracheal intubation. Rats were briefly mechanically ventilated in room air, extubated, then killed after 16 (n = 6), 24 (n = 6), 48 (n = 6), and 72 hours (n = 4). Control animals received the same volume of normal saline (n = 7) or no meconium (n = 7). Bronchoalveolar lavage and tissue specimens were evaluated for inflammatory cells, total proteins, surfactant phospholipids, and surfactant proteins. RESULTS: Meconium caused exudative lung injury that was reflected in increased cell counts and proteins in alveolar lavage fluid. The peak injury occurred at 16 hours after instillation, whereas recovery occurred by 72 hours. Although total lavage fluid phospholipids did not change over time, phospholipid and dipalmitoyl phosphatidylcholine in large aggregates tended to decrease at 24 hours. Western blot analysis demonstrated time-dependent qualitative decreases in surfactant proteins A and B (SP-A, SP-B) in meconium-instilled animals compared with the controls. ELISA for SP-B confirmed the Western blot findings with total SP-B in large aggregate decreasing from 25 +/- 4 microg in controls to 6.6 +/- 0.8 microg at 24 hours of injury. CONCLUSIONS: Our study suggests that the exudative lung injury with meconium instillation is associated with decreased levels of SP-A and SP-B in the large aggregate fraction of lung surfactant. We speculate that decreased secretion and/or increased degradation accounts for lower levels of SP-B in bronchoalveolar lavage fluid.

Animals↗