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Biomedical subjects

V Bomfim

Publications and source records attributed to V Bomfim.

At least 19 recordsLinked to original sources
PubMed2001

High early patency of saphenous vein graft for coronary artery bypass harvested with surrounding tissue.

BACKGROUND: Surgical trauma to the saphenous vein, used as a conduit for coronary artery bypass grafting, affects their occlusion rate. This study evaluates the early patency of saphenous vein grafts harvested with a pedicle of surrounding tissue that protects the vein from spasm and trauma. METHODS: Fifty-two patients underwent coronary artery bypass grafting with saphenous veins harvested with surrounding tissue. Forty-five patients, who received a total of 124 vein grafts and 42 left internal mammary arteries, underwent angiographic follow-up at a mean of 18 months (9 to 24 months). RESULTS: Patency for saphenous vein grafts was 95.4% and for left internal mammary arteries, it was 93.3%. Twenty-nine of 30 (96.7%) vein grafts anastomosed to arteries 2.0 mm or more, 65 of 67 (97%) grafts to 1.5 mm, and 10 of 13 (77%) anastomosed to 1-mm arteries were patent. Nineteen of 22 (86.4%) vein grafts with flow rates 20 mL/min or less, 32 of 34 (94.1%) with flow between 20 and 40 mL/min, and 50 of 51 (98%) with flow more than 40 mL/min were patent. Other registered surgical and clinical factors did not contribute to vessel occlusion. CONCLUSIONS: Early patency rate of saphenous veins harvested with surrounding tissue is very high, even in saphenous vein grafts demonstrating low blood flow. Preservation of graft endothelium using our harvesting technique may be the explanation of this success.

Adult↗
PubMed2001

Preserved endothelial integrity and nitric oxide synthase in saphenous vein grafts harvested by a 'no-touch' technique.

BACKGROUND: The saphenous vein is the most commonly used conduit for coronary artery bypass surgery, but 1-year occlusion rates as high as 30 per cent have been reported. In conventional surgery, considerable damage to the vein occurs during harvesting. The aim of this study was to compare endothelial integrity and nitric oxide synthase (NOS) in saphenous veins harvested by a novel 'no-touch' technique and veins harvested conventionally. METHODS: Immunohistochemistry was used to study endothelial integrity, and a combination of histochemistry and autoradiography was employed to identify NOS in human saphenous veins harvested by conventional and no-touch techniques. RESULTS: The endothelial lining of conventional grafts was reduced compared with that of no-touch grafts (52 versus 73 per cent; P = 0.04). This was associated with a concomitant reduction of NOS availability; NOS was also present in the adventitial vasa vasorum of no-touch vessels. CONCLUSION: Some of the sites with potential for nitric oxide release in vivo are removed during conventional saphenous vein harvesting. These sites were preserved after no-touch harvesting, suggesting the potential to improve coronary artery bypass graft patency.

Aged↗
PubMed1999

"No-touch" technique using saphenous vein harvested with its surrounding tissue for coronary artery bypass grafting maintains an intact endothelium.

Spasm and consequent dilation of the saphenous vein (SV) for coronary artery bypass grafting (CABG) can be avoided if the vein is harvested with its surrounding tissue. Morphologic techniques, including scanning and transmission electron microscopy, were used to compare endothelial cell integrity using three SV harvesting procedures: conventional (adventitial stripping of the vein, manual distention and storing in saline); intermediate (after adventitial stripping, the vein was left in situ, covered with a papaverine-soaked compress, and stored in heparinized blood); and "no-touch" (SV dissected with its surrounding tissue was left in situ, covered with a saline-soaked compress and stored in heparinized blood). Preservation of endothelial cell integrity was greater with the "no-touch" procedure than with the other methods. Since endothelial cell integrity of SV grafts may affect the patency rate, we conclude that the "no-touch" preparation should improve the results of CABG.

Anticoagulants↗
PubMed1995

[Ambulatory follow-up of patients with myelomeningocele in a pediatric hospital].

Myelomeningocele is the most common congenital malformation of the nervous system and despite its complexity and involvement of multiple organs is compatible with long survival. The peculiar characteristics of this malformation expose myelomeningocele patients to acute and chronic care problems with effects in quality of survival. In order to evaluate the quality of the follow-up of spina bifida patients in a pediatric hospital, the authors examined 54 patients attending the neurosurgical outpatient unity of a pediatric hospital. The lack of a multidisciplinary spina bifida clinic in Rio de Janeiro forced the patients to pursuit for complimentary medical and paramedical care outside the hospital with significant effects in the quality of survival. In consequence, only 25% of the patients were able to walk and community ambulation was nearly absent. Only 66.6% had a regular rehabilitation program and nearly 50% had routine orthopedics consultations. Almost half of the patients had no urological referral at all and 75% were incontinent, with recurrent urinary infections ranging 72.2%. The rates of neurosurgical complications were similar to those observed in the literature. We concluded that the quality of survival of patients with neural tube defects is strongly influenced by the adverse socio-economical conditions and the lack of a spina bifida multidisciplinary clinic.

Adolescent↗
PubMed1994

Mitral mechanical valve without long-term anticoagulation. Eight-year follow-up.

In 12 patients with sinus rhythm (including 5 children and 6 young women), mitral valve replacement was performed with a microporous-surfaced valve similar to the Björk-Shiley Monostrut. After the first 3 months, permitting endothelialization of the suture ring to continue over the groove and adjacent metal valve ring, no long-term anticoagulant treatment was given. There was no thromboembolic complication in this group during follow-up for 6-8 years, during which four women gave birth to a total of seven children. In eight other cases, one mitral case with atrial fibrillation, anti-coagulant was not discontinued, and in the remaining aortic cases it was reinstituted. One of them (with atrial fibrillation) had hematuria during inadequate anticoagulant medication, but no thromboembolism. Of five patients with only aortic valve replacement, two had thromboembolic complications, one without residual symptoms and one with slight hand weakness. Another had a transient ischemic attack while on anticoagulant and acetylsalicylic acid was added. Two patients with aortic and mitral valve replacement died, one from heart tamponade and the other from venous thrombosis with pulmonary embolism.

Adolescent↗
PubMed1989

Sickle cell anemia and mitral valve replacement. Case report.

An 8-year-old black boy with sickle cell disease and severe hemolytic anemia crisis (95% hemoglobin S) also had mitral incompetence due to rheumatic valve disease. A 27 mm monostrut Björk-Shiley valve prosthesis was implanted after partial exchange transfusions had reduced the hemoglobin S to less than 40%. High-flow normothermic perfusion was used during extracorporeal circulation, with care taken to avoid hypoxia and acidosis. Postoperative recovery was uneventful.

Anemia, Sickle Cell↗
PubMed1988

Surgical treatment of active valvular infective endocarditis.

A review is presented of 20 patients consecutively operated on for acute valvular endocarditis. The diagnosis was established from at least two of the criteria: (a) typical clinical features, (b) two blood cultures positive for the same causal microorganism, and (c) echocardiographic evidence of vegetations. In all cases there was histologic evidence of active infection in the surgical specimen. Only three of the 20 patients had no previous cardiac disease. The most common causal agent was Staphylococcus aureus. The indications for surgery were refractory cardiac failure or infection (18 and 2 cases, respectively). Aortic valve replacement was performed in 16 of the 20 cases, suggesting that aortic valvulopathy aggravates the course of infective endocarditis and increases the risk of heart failure. The overall mortality rate was 30%. All surviving patients were infection-free at postoperative bacteriologic follow-up. Surgery is considered to be the management of choice in active valvular, therapy-resistant bacterial endocarditis with or without cardiac failure.

Adolescent↗
PubMed1987

Adenine nucleotide degradation in the human myocardium during cardioplegia.

The tissue content of adenine nucleotides and their metabolites, inosine monophosphate, adenosine, hypoxanthine, and uric acid, were determined in biopsy specimens from the left ventricle of six patients during cardioplegia for open heart surgery. Biopsy specimens were collected immediately after the induction and at the end of cardioplegia (51-82 min) and were analysed by high performance liquid chromatography. After the induction of cardioplegia (cold potassium enriched solution) the left coronary artery was continuously perfused with cold (10 degrees C), potassium enriched, diluted blood. The adenosine triphosphate concentration decreased from 13 to 8 mmol.kg-1 dry muscle (p less than 0.01) during cardioplegia. Adenosine diphosphate and adenosine monophosphate concentrations were 6 and 3 mmol.kg-1 dry muscle respectively and remained unaffected. The adenosine concentration (0.3 mmol.kg-1 dry muscle) was three times higher than that of inosine monophosphate. Inosine concentrations increased from 0.8 to 2.7 mmol.kg-1 dry muscle (p less than 0.01) in parallel with the increase in hypoxanthine from 0.1 to 0.4 mmol.kg-1 dry muscle (p less than 0.01). The total adenine nucleotide pool decreased by 5 mmol.kg-1 dry muscle (p less than 0.01), whereas the corresponding increase in nucleotides and bases only was 2 mmol.kg-1 dry muscle. In conclusion, the adenosine triphosphate content and the adenine nucleotide pool were appreciably reduced during continuous cold blood cardioplegia as used in the present study. The tissue content of adenosine and further metabolites was considerably increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗
PubMed1987

Myocardial energy metabolism in the induction phase of cardioplegia in relation to myocardial temperature during open heart surgery.

Changes in myocardial high energy phosphate and lactate concentrations during initiation of cardioplegia for open heart surgery were studied in 21 patients and related to their individual myocardial temperatures. Left ventricular myocardial biopsies were taken 10 min post aortic cross-clamping and were analysed for ATP, creatine phosphate (CP), creatine (C) and lactate. The patients were divided into three groups according to the achieved myocardial temperature: 6-10 degrees C, 11-15 degrees C and 16-24 degrees C. The results indicated that optimal myocardial protection during the induction phase of the cardioplegia was obtained in the 11-15 degrees C group in which the highest ATP concentration and simultaneously lowest lactate concentration was maintained.

Adenosine Triphosphate↗
PubMed1986

Myocardial metabolism during aortic valve replacement. I. Hypothermic crystalloid cardioplegia with mannitol.

Myocardial energy metabolism during hypothermic potassium cardioplegia with addition of mannitol was studied in five patients undergoing aortic valve replacement. Myocardial biopsies were taken from the left ventricle 10 min after the aortic cross-clamping and immediately before declamping and were analyzed for ATP, lactate and glycogen. The ATP concentration fell (13.2 +/- 3.6-11.0 +/- 4.3 mmol X kg-1 dry muscle), the lactate concentration rose (61.5 +/- 17.6-86.6 +/- 13.3) and glycogen decreased (181 +/- 54-143 +/- 3 mmol X kg-1 d.m.). Use of mannitol in a crystalloid cardioplegia solution does not prevent pronounced anaerobic metabolism in the myocardium during aortic valve replacement.

Adenosine Triphosphate↗
PubMed1986

Myocardial metabolism during aortic valve replacement. II. Bolus infusion of cold blood for cardioplegia.

Myocardial energy metabolism during hypothermic potassium cardioplegia with blood as the cardioplegia vehicle, given in one or two bolus doses, was studied in eight patients undergoing aortic valve replacement. Myocardial biopsies were taken from the left ventricle 10 min after aortic cross-clamping (a.c.) and immediately before declamping (d.c.) and were analyzed for ATP, creatine phosphate (CP), creatine (C) and lactate. The interindividual range of myocardial temperature was 11-19 degrees C at 10 min a.c. and 11-25 degrees C immediately before d.c. The myocardial ATP concentration fell (17.2 +/- 5.7-12.8 +/- 2.8 mmol X kg-1 dry muscle), the lactate concentration rose (64.7 +/- 35.8-136 +/- 33.8 mmol X kg-1 d.m.) and the total creatine pool (CP + C) was unchanged. Hypothermic blood cardioplegia conferred fairly good initial protection of the myocardium, but the reduction in ATP and the great lactate accumulation towards the end of cardioplegia, especially in patients with myocardial temperature reaching 19-25 degrees C, indicates that such protection is adequate only if the myocardial temperature is maintained between 11 and 18 degrees C.

Adenosine Triphosphate↗
PubMed1986

Myocardial metabolism during aortic valve replacement. III. Continuous infusion of cold blood for cardioplegia.

Myocardial energy metabolism during hypothermic potassium cardioplegia with blood as the cardioplegia vehicle was studied in eight patients undergoing aortic valve replacement. Cardiac arrest was induced with a single bolus infusion and maintained by continuous perfusion. Myocardial biopsies were taken from the left ventricle 10 min after aortic cross-clamping (a.c.) and immediately before declamping (d.c.) and were analyzed for ATP, creatine phosphate (CP), creatine (C) and lactate. The interindividual range of myocardial temperature was 15-21 degrees a.c. and 17-22 degrees C immediately before d.c. The ATP concentration decreased (12.7 +/- 3.9-10.4 +/- 3.5 mmol X kg-1 dry muscle), the lactate concentration increased (102 +/- 30-156 +/- 8 mmol X kg-1 d.m.), and the total creatine (CP + C) remained constant. Induction of cardioplegia by blood resulting in a mean myocardial temperature of 19 degrees C could not prevent anaerobic metabolism. The changes in ATP levels between 10 min after a.c. and just before d.c. were small, however, indicating that oxygen delivery during continuous blood cardioplegia at a myocardial temperature of c. 20 degrees C prevented further loss of ATP. The lactate concentration, however, increased markedly between 10 min after a.c. and d.c., demonstrating that a significant proportion of the total metabolism was anaerobic.

Adenosine Triphosphate↗
PubMed1985

Myocardial energy depletion during profound hypothermic cardioplegia for cardiac operations.

Myocardial biopsy specimens were taken from 10 patients undergoing aortic valve replacement using extracorporeal circulation and continuous perfusion blood cardioplegia at extremely low myocardial temperature (10 degrees C). They were analyzed for adenosine triphosphate, creatine phosphate, creatine, and lactate before, after 10 minutes, and after 60 minutes of cardioplegia. Patient inclusion criteria were heart volume less than 700 ml/m2 body surface area and no significant coronary atherosclerosis as judged from preoperative angiograms. The profound hypothermic cardioplegia resulted in a smaller intramyocardial lactate accumulation but a greater decrease in adenosine triphosphate and creatine phosphate than a moderate reduction of myocardial temperature (15 degrees C) as previously reported in a similar patient group. This suggests that at the lower temperature energy-generating processes are thwarted more than energy consumption. In addition, the profound hypothermic cardioplegia led to a reduction of the myocardial pool of total creatine, which may delay restitution of myocardial high-energy phosphate and function after cardioplegia.

Adenosine Triphosphate↗
PubMed1983

Optimal insertion technique for the Björk-Shiley valve in the narrow aortic ostium.

The Björk-Shiley tilting disc valve was used for aortic valve replacement (AVR) in 250 consecutive patients between 1977 and 1982. One hundred and ninety-six patients had isolated AVR, and 54 had combined procedures (double- or triple-valve replacement in 31, associated coronary artery bypass grafting in 20, and miscellaneous procedures in 3). A special technique for inserting large Björk-Shiley valves without using outflow patches or annuloplastic procedures was developed. This method included allowing the right portion of the aortic incision to end about 0.5 cm above the noncoronary sinus; the use of simple interrupted sutures; placement of the prosthetic sewing ring on top of the annulus of the noncoronary sinus, thereby tilting the valve slightly in the outflow tract; and routine orientation of the major opening of the valve toward the annulus of the noncoronary sinus. This orientation resulted in the largest effective orifice area at postoperative catheterization. None of the male patients received a valve smaller than 23 mm, and none of the female patients were given a valve smaller than 21 mm. The convexoconcave model of the Björk-Shiley valve was used in 71% of the patients. An outflow patch was required only in 1 patient with concomitant supravalvular stenosis of the aorta. The combination of adequate myocardial protection, comparatively short aortic cross-clamping times, and the use of large, properly oriented Björk-Shiley valves resulted in satisfactory postoperative hemodynamics in all patients. In fact, none of the 196 patients undergoing isolated AVR and only 5 (9%) of the 54 patients undergoing combined procedures required postoperative inotropic stimulation. There were no operative deaths, and all patients left the hospital in good condition. The Björk-Shiley tilting disc valve is a reliable and well-functioning aortic valve substitute that is particularly suited for patients with narrow aortic ostia. With attention to certain details in the insertion technique, encouraging clinical results can be obtained with this prosthesis.

Adult↗
PubMed1982

Myocardial and non-myocardial release of myoglobin and creatine-kinase MB following cardiac operations with hypothermic potassium cardioplegia.

Serum time-activity curves for myoglobin, creatine-kinase (CK) and its isoenzyme MB were determined during and after coronary bypass surgery and aortic valve replacement. Hypothermic potassium cardioplegia was the method employed to initiate cardiac arrest. Cardiac myoglobin and CK-MB release rates were maximal 0.5 to 1.0 h post aortic cross-clamp release (PACR) with maximal concentrations at 1 and 4 h PACR respectively. The cardiac release ceased within 5 h PACR but was followed by a noncardiac release with maximal concentrations from 10 to 35 h PACR. The cardiac myoglobin release was significantly lower in the coronary bypass group, whereas no significant intergroup difference was observed for CK-MB. The cumulative CK-MB release corresponded roughly to about 5 g of myocardium.

Aortic Valve↗