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Biomedical subjects

N A Stolf

Publications and source records attributed to N A Stolf.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

Dynamic cardiomyoplasty in the treatment of dilated cardiomyopathy: current results and perspectives.

BACKGROUND: The purpose of this article is to provide an overview of the current indications, results, and perspectives of dynamic cardiomyoplasty in the treatment of patients with dilated cardiomyopathy. Particular emphasis is placed on the clinical experience with 36 patients operated at the São Paulo Heart Institute between 1988 and 1995. METHODS: Based on several clinical reports, the mechanisms of action of dynamic cardiomyoplasty in these patients include the enhancement of left ventricular systolic function, by the direct action of synchronized skeletal muscle flap contraction and the reversion of chamber remodeling. Moreover, both mechanisms seem to be responsible for improved diastolic function properties and for the decrease of ventricular wall stress. Besides the acceptable hospital mortality observed for patients with dilated cardiomyopathy ranging from 0% to 8% with this surgical procedure, clinical improvement after dynamic cardiomyoplasty has been demonstrated as a prevailing and significant outcome. RESULTS: Nevertheless, the 1-year survival for these patients ranges from 82% to 86% and the 5-year survival on the order of 41% to 49%. In addition, the analysis of factors influencing the outcome showed that cardiomyoplasty long-term survival was significantly affected by the severity of preoperative clinical compromise and cardiac function impairment. On the other hand, patients with dilated cardiomyopathy who were operated in functional Class III or intermittent Class IV and with pulmonary vascular resistance below 4 Wood units, present survival rates on the order of 79% at 2 years and of 64% at 5 years of follow-up, which are similar to those reported after cardiac transplantation. CONCLUSIONS: Furthermore, technological advances incorporated in the new cardiomyostimulators may ameliorate skeletal muscle flap performance at long term. Other developments are also discussed in this field.

Cardiomyopathy, Dilated↗
PubMedDate not supplied

Self-expanding endovascular stent-graft implant for treatment of descending aortic diseases.

BACKGROUND: Aneurysms and dissections involving the descending thoracic aorta and the distal portion of the aortic arch are difficult to resolve surgically. The introduction of endovascular self-expanding stent-grafts has simplified the operation. Given the complications associated with their peripheral placement, we explored the feasibility of surgical insertion. METHODS: Thirteen patients underwent surgical insertion of a stent-graft into the aortic arch via longitudinal aortotomy. Six patients had aneurysms (ruptured in two, and seven dissections (acute in two, ruptured in one). Five patients also underwent associated procedures including aortic valve replacement (one), ascending aorta replacement (two), arch replacement (one), and coronary artery bypass (one). RESULTS: There was one intraoperative death due to ascending aortic dissection, and two hospital deaths due to multiple complications. Of ten patients discharged, one died 3 months postoperatively. The remaining survivors are well, and imaging studies confirmed adequate correction of the aortic disease. CONCLUSIONS: The use of this technique simplifies the operation and treatment of particular cases of aortic disease. The observed morbidity and mortality are due to factors independent of the technique.

Aged↗
PubMedDate not supplied

Ischemic preconditioning in myocardial revascularization with intermittent aortic cross-clamping.

BACKGROUND: This study tests the hypothesis that initial brief periods of ischemia can increase the protection obtained by intermittent aortic cross-clamping. METHODS: In the control group (n = 18), the procedure was performed under intermittent aortic cross-clamping at 32 degrees C. Patients in the preconditioned gorup (n = 17) received a stimulus of two 3-minute periods of cross-clamping followed by 2 minutes of reperfusion prior to standard operation. CKMB, troponin 1, adenosine, and lactate were obtained from the great cardiac vein at the onset of cardiopulmonary bypass (CPB), at the end of the first anastomosis, and at the end of CPB. RESULTS: CKMB and troponin I were slightly higher at the end of CPB in the control group, while there was no difference between adenosine and lactate levels. [table: see text]. CONCLUSION: There was no difference between groups in terms of myocardial protection.

Adenosine↗
PubMedDate not supplied

Unusual abdominal tumors with intracardiac extension. Two cases with successful surgical resection.

Abdominal tumors that can grow through vascular lumen and spread to the right heart are rare. Although these tumors have different histologic aspects, they may cause similar abdominal and cardiac symptoms and are a serious risk factor for pulmonary embolism and sudden death when they reach the right atrium and tricuspid valve. The best treatment is radical surgical resection of the entire tumor using cardiopulmonary bypass with or without deep hypothermia and total circulatory arrest. We report the cases of two patients, the first with leiomyosarcoma of the inferior vena cava and the other with intravenous leiomyomatosis of the uterus that showed intravascular growth up to right atrium and ventricle, who underwent successful radical resection in a one-stage procedure with the use of cardiopulmonary bypass. We discuss the clinical and histologic aspects and imaging diagnosis and review the literature.

Adult↗
PubMedDate not supplied

Prostacyclin in the management of pulmonary hypertension after heart transplantation.

Right ventricular failure after heart transplantation has been well documented as a major determinant of patient outcome. In 50 patients undergoing orthotopic heart transplantation, nine male patients with an average age of 41 years had in the immediate postoperative period a syndrome that consisted of low cardiac index, high right atrial and pulmonary artery pressures, and high pulmonary vascular resistance. The preoperative data showed: right atrial pressure, 9 +/- 6 mm Hg; pulmonary pressure, 38 +/- 10 mm Hg; cardiac index, 1.6 +/- 0.4 L/min/m2; pulmonary vascular resistance, 466 +/- 91 dynes/sec/cm-5; pulmonary wedge pressure, 15 +/- 6 mm Hg; and systemic vascular resistance, 2089 +/- 290 dynes/sec/cm-5. The immediate postoperative data revealed: right atrial pressure, 17 +/- 5; pulmonary artery pressure, 32 +/- 8; cardiac index, 2.2 +/- 0.7; pulmonary vascular resistance, 421 +/- 368; pulmonary wedge pressure, 15 +/- 6; systemic vascular resistance 1318 +/- 263. All of these patients were receiving inotropic and vasodilator drugs with no improvement after volume challenge. Prostacyclin was started, and the dose increased from 0.5 to 5.0 ng/kg/min, until an increase in cardiac index and a reduction in pulmonary resistance were achieved. The final profile was right atrial pressure, 12 +/- 5; pulmonary artery pressure, 24 +/- 6; cardiac index, 3.7 +/- 1.2; pulmonary vascular resistance, 122 +/- 42; pulmonary wedge pressure, 14 +/- 4; systemic vascular resistance, 870 +/- 263. The use of prostacyclin enabled the weaning of other drugs within a 48-hour period with no side effects and no worsening of the hemodynamic conditions after discontinuation of prostacyclin.

Adult↗
PubMedDate not supplied

Biomechanical circulatory assistance. Importance of aerobic capacity of normal and conditioned skeletal muscles.

To define more efficient use of biomechanical circulatory assistance, the contracting and fatigue characteristics of normal and conditioned latissimus dorsi of seven adult mongrel dogs were analyzed. The conditioned muscles underwent vascular adaptation and electrical stimulation with burst frequency of 50 Hz in rates of 60 and 120 contractions per minute for 6 to 8 weeks. They were compared with unconditioned contralateral controls by isometric force measurements. Normal and transformed muscles exhibited the same optimum pacing parameters (burst frequencies from 50 Hz up and train durations from 150 msec) with supramaximal amplitude stimulation. Conditioned muscles showed initial smaller forces (-27%) and longer contraction times (+32%). Fatigue curves of unconditioned muscles for different duty cycles showed marked initial decreases and proportional stable values of force after some minutes, with equal final tension time indexes under these conditions (20 +/- 3 KgF seg/min 100 g). Conditioned muscles maintained stable force for same duty cycles and a greater tension time index during prolonged conditions (68 +/- 6 KgF seg/min 100 g). This study revealed that normal and conditioned skeletal muscles are capable of maintaining steady state work depending upon their aerobic capacity and suggests that these muscles may undergo adaptive transformation while contracting in a synchronous fashion with the heart during variable duty cycles.

Adaptation, Physiological↗
PubMedDate not supplied

Heart transplantation in patients with Chagas' disease cardiomyopathy.

Among 26 heart transplant patients, four had Chagas' disease cardiomyopathy. They were male patients, aged 28 to 43 years; three were in New York Heart Association class IV, and one was in class II but with refractory arrhythmias. The immunosuppressive protocol was cyclosporine and steroids in the first patient, and cyclosporine, azathioprine, and steroids in the last patient. Three patients had one or more rejection episodes, and one had none. One patient had a lymphoproliferative intestinal disease. Three patients had a new acute phase of Chagas' disease in postoperative days 59, 81, and 420, with fever, skin lesions, and myocarditis. The Trypanosoma cruzi was found in skin lesions in all three patients and in the myocardial biopsy in two patients. The laboratory tests did not show the expected results for the acute phase. All the alterations were reversed by specific therapy in a few days. One patient died on postoperative day 197 from rejection, and the immunosuppression was diminished because of the lymphoproliferative disease; the others were well 107, 160, and 500 days after the transplantation. The conclusions were as follows: (1) It seems that steroid pulse therapy predisposes the patient to a new acute phase of Chagas' disease. (2) Clinical presentation and laboratory test results of the acute phase are not the usual. (3) Specific drug therapy reverses all the alterations of this acute phase in a few days. (4) Although additional care is necessary and specific complications are expected, heart transplantation can be done with good results in patients with Chagas' cardiomyopathy.

Adult↗