João Roberto Breda

Cardiac baroreflex is already blunted in eight weeks old spontaneously hypertensive rats

Background The literature did not evidence yet with which age spontaneously hypertensive rats (SHR) start to present baroreflex reduction. We endeavored to evaluate the baroreflex function in eight-week-old SHR. Methods Male Wistar Kyoto (WKY) normotensive rats and SHR aged eight weeks were studied. Baroreflex was calculated as the variation of heart rate (HR) divided by the mean arterial pressure (MAP) variation (ΔHR/ΔMAP) tested with a depressor dose of sodium nitroprusside (SNP, 50 μg/kg) and with a pressor dose of phenylephrine (PHE, 8 μg/kg) in the right femoral venous approach through an inserted cannula in the animals. Significant differences for p < 0.05. Results Baseline MAP (p < 0.0001) and HR (p = 0.0028) was higher in SHR. Bradycardic peak was attenuated in SHR (p < 0.0001), baroreflex gain tested with PHE was also reduced in the SHR group (p = 0.0012). PHE-induced increase in MAP was increased in WKY compared to SHR (p = 0.039). Bradycardic reflex responses to intravenous PHE was decreased in SHR (p < 0.0001). Conclusion Eight weeks old SHR already presents impairment of the parasympathetic component of baroreflex.

Saphenofemoral arteriovenous fistula as hemodialysis access

BackgroundAn upper limb arteriovenous (AV) fistula is the access of choice for haemodialysis (HD). There have been few reports of saphenofemoral AV fistulas (SFAVF) over the last 10-20 years because of previous suggestions of poor patencies and needling difficulties. Here, we describe our clinical experience with SFAVF.MethodsSFAVFs were evaluated using the following variables: immediate results, early and late complications, intraoperative and postoperative complications (up to day 30), efficiency of the fistula after the onset of needling and complications associated to its use.ResultsFifty-six SFAVF fistulas were created in 48 patients. Eight patients had two fistulas: 8 patent (16%), 10 transplanted (20%), 12 deaths (24%), 1 low flow (2%) and 20 thrombosis (39%) (first two months of preparation). One patient had severe hypotension during surgery, which caused thrombosis of the fistula, which was successfully thrombectomised, four thrombosed fistulae were successfully thrombectomised and revised on the first postoperative day. After 59 months of follow-up, primary patency was 44%.ConclusionSFAVF is an adequate alternative for patients without the possibility for other access in the upper limbs, allowing efficient dialysis with good long-term patency with a low complication rate.

Topical use of antifibrinolytic agent to reduce postoperative bleeding after coronary artery bypass surgery

OBJECTIVE Antifibrinolytic agents reduce bleeding after cardiac surgery, but there are adverse effects after their systemic use. These effects are avoided by topical application of antifibrinolytic agents in pericardial cavity. We compared the effects of topically applied epsilon-aminocaproic acid (EACA) and placebo on postoperative bleeding and transfusion requirements after coronary artery bypass surgery. METHODS In this single center prospective, randomized, double-blind trial, 53 patients were randomized into two groups to receive EACA (24 g in 250 ml of saline solution) or placebo (250 ml of saline solution) before sternal closure. Groups were comparable with respect to all preoperative and intraoperative variables. Postoperative bleeding, transfusion requirements and hematologic parameters were evaluated. RESULTS Postoperative bleeding within first 24 hours (h) period (EACA group 154.66+/-74.64 x Placebo group 220.21+/-136.42 ml; P=0.031) showed statistically significant inter-group difference, within 48 h (EACA group 259.14+/-420.07 x Placebo group 141.67+/-142.58 ml; P=0.614), as well as cumulative blood loss (EACA group 832.07+/-576.86 x Placebo group 827.50+/-434.12 ml; P=0.975), not showed statistically inter-group differences. Inter-group difference of blood product requirements was statistically significant (EACA group 185.90+/-342.07 x Placebo group 439.42+/-349.07 ml; P=0.016). Laboratory analyses showed no differences between the two groups postoperative (hematologic characteristics: hemoglobin (g/dl)- EACA group 9.18+/-0.92 x Placebo group 8.85+/-1.48 g/dL; P=0.11; hematocrit (%)-EACA group 28.15+/-3.35 x Placebo group 26.67+/-4.15%; P=0.06). CONCLUSION Topical use of epsilon aminocaproic acid reduces postoperative bleeding in the first 24 hours and requirements of blood transfusion after coronary artery bypass graft surgery.

Surgical ablation of atrial fibrillation using radiofrequency

OBJECTIVE To evaluate the effectiveness of intraoperative atrial fibrillation ablation using radiofrequency during mitral valve procedure. This report describes the early and midterms results. METHODS Between September 2003 and September 2005, 15 patients with mitral disease were operated. All patients were in chronic atrial fibrillation and with congestive symptoms despite full medication. The patients were analysed according to clinical criteria, electrical and echocardiographic findings. RESULTS There were no hospital mortality or complications related to radiofrequency ablation. The mean follow-up period was 12.16 +/- 10.29 months. All patients left operating room in sinus rhythm, however, before hospital discharge, only nine (60%) were in regular cardiac rhythm. During follow-up, two patients presented atrial fibrillation recurrence and currently seven (46.7%) keep sinus rhythm. CONCLUSION Despite low morbimortality related to the procedure, initial results in this report showed a less effectiveness of this technique when compared with other papers.

A Randomized Trial of the Topical Effect of Antifibrinolytic Epsilon Aminocaproic Acid on Coronary Artery Bypass Surgery Without Cardiopulmonary Bypass

We assessed the effect of the topical application of epsilon-aminocaproic antifibrinolytic acid (EACA) on the pericardium of patients submitted to coronary artery bypass graft (CABG) without the use of cardiopulmonary bypass (CPB). This is a prospective, randomized, and double-blind study. We evaluated 26 patients with chronic coronary heart disease indicated for CABG without CPB (EACA and placebo groups). The analysis of the postoperative hematological results showed no difference between groups in hemoglobin and hematocrit. There was no difference between the groups regarding the postoperative bleeding through the drains in the first 24 hours, 48 hours, and accumulated loss until removal of drains. The use of EACA in patients undergoing CABG without CPB presented no difference in the reduction of the amount of bleeding and the need for blood transfusions.

An experience of vascular access for hemodialysis in Brazil

Background The analysis of hemodialysis services is relevant for the quality of life of patient. In this study we investigated the profile of vascular access used for hemodialysis patients in our Unit. Methods We evaluated 219 patients of both genders aged over 18 years old who have undergone implant or manufacture of vascular hemodialysis access. We excluded patients on renal replacement therapy by peritoneal dialysis. Results Associated diseases were hypertension and diabetes mellitus. 161 had arteriovenous fistula, with 153 held by the same dialysis and nine of them were still maturing. 27 patients on dialysis used central venous catheter. 148 were indigenous and five were made using polytetrafluoroethylene prosthesis (PTFE). Among the 27 patients with central venous catheters, ten used short-term catheter and 17 used long-term catheter. The most frequent type of fistula use was on the radio distal cephalic, in 85 patients (52.5%), followed by radio cephalic proximal in 26 patients (16%). The number of fistulas in dialysis patients conducted by this kind of therapy ranged from one to ten and in 64 patients (41.83%) fistula was the first and only to be made. Among the fistula for dialysis patients, the highest prevalence was radio cephalic fistula in 111 patients (72.5%) and mean duration of use was 48.1 months, ranging from two months to 17 years. Conclusion Our Unit of hemodialysis is above the limits established by international norms.

Miocardiopatia terminal com insuficiência mitral secundária: tratamento com implante de prótese e remodelamento interno do ventrículo esquerdo

OBJECTIVE: To present a new surgical approach that consists of the implantation of a mitral prosthesis smaller than the annulus with traction of the papillary muscles to reduce the sphericalness of the left ventricle. METHODS: Between December 1995 and September 2005, 116 heart disease patients were operated, all of whom were at end-stage despite of full medication. The patients were analysed according to clinical criteria, echocardiographic findings and morphology of the left ventricle. RESULTS: Hospital mortality was 16.3% (19/116) and mid-term follow-up (38 ± 16 months) showed evidence of improvement in the clinical status and some echocardiographic parameters, in particular reduction of the sphericalness of the left ventricle. CONCLUSION: This technique, despite of the high mortality rate, offers a promising therapeutic alternative for the treatment of patients in refractory heart failure with cardiomyopathy associated to moderate or severe secondary mitral regurgitation.

Avaliação inicial da ablação operatória biatrial por radiofrequência de fibrilação atrial

OBJECTIVE To evaluate the results of intraoperative radiofrequency ablation with biatrial procedure in the treatment of chronic atrial fibrillation in patients with associated cardiac disease. METHODS Between February 2008 and May 2009, 15 consecutive patients were underwent mitral valve procedure plus modified radiofrequency biatrial ablation of chronic atrial fibrillation. The mean age was 47.73 +/- 9.85 years and 60% were male. The mean left atrial diameter was 55.06 +/- 7.56 mm. RESULTS There were no hospital mortality or complications related to radiofrequency ablation. The mean follow-up period was 7 +/- 4 months. At the time of hospital discharge nine (60%) patients were in sinus rhythm. After a mean follow-up period 11 (73.3%) were in sinus rhythm. CONCLUSION Intraoperative biatrial radiofrequency ablation is a safe and effective technique for the treatment of chronic atrial fibrillation, with satisfactory midterms outcomes in terms of conversion to sinus rhythm.

Efeito da denervação cardíaca ventral na incidência de fibrilação atrial após revascularização cirúrgica do miocárdio

OBJECTIVE To evaluate the effect of ventral cardiac denervation in the incidence of atrial fibrillation after coronary artery bypass surgery. METHODS Between September and November, 50 patients without history or previous diagnosis of atrial arrhythmia from the same institution presenting coronary heart disease with indication for coronary artery graft bypass surgery were enrolled in a prospective and randomized study. The exclusion criteria were: patients older than 75 years of age, previous history of atrial arrhythmia and associated heart surgeries. Denervation was performed before cardiopulmonary bypass and it was achieved by removing the adipose tissues around the superior vena cava, aorta and pulmonary artery. The groups were compared regarding demographic, clinical and operative variables. RESULTS There were no hospital mortalities. The additional time for the denervation was 7.64+/-2.33 minutes, and there were no associated complications. Postoperative atrial fibrillation was present in two (8%) patients of the Control Group and in three (12%) patients who underwent ventral cardiac denervation. The risk of postoperative atrial fibrillation in patients undergoing ventral cardiac denervation was 22% higher than in the Control Group (0.56-2.66,confidence interval); however, this outcome was not statistically significant (p=0.64). CONCLUSION Ventral cardiac denervation, despite being a fast and low-risk procedure, does not significantly reduce the incidence of atrial fibrillation after coronary artery bypass graft surgery.

Mitral implant of the Inovare transcatheter heart valve in failed surgical bioprostheses: a novel alternative for valve-in-valve procedures

Objectives Reoperative procedure for the treatment of a failed mitral bioprosthesis is associated with considerable risk. In some cases, mortality is high and might contraindicate the benefit of the procedure. The minimally invasive valve-in-valve (ViV) transcatheter mitral valve implant offers an alternative less-invasive approach, reducing morbidity and mortality. The objective of this paper was to evaluate the mitral ViV approach using the Braile Inovare prosthesis. Methods The transcatheter balloon-expandable Braile Inovare prosthesis was used in 12 cases. Procedures were performed in a hybrid operating room, under fluoroscopic and echocardiographic control. Through left minithoracotomy, the prostheses were implanted through the cardiac apex. Serial echocardiographic and clinical examinations were performed. Follow-up varied from 1 to 30 months. Results A total of 12 transapical mitral ViV procedures were performed. Patients had a mean age of 61.6 ± 9.9 years and 92% were women. Mean logistic EuroSCORE was 20.1%. Successful valve implantation was possible in all cases. In one case, a right lateral thoracotomy was performed for the removal of an embolized prosthesis. There was no operative mortality. Thirty-day mortality was 8.3%. Ejection fraction was preserved after the implant (66.7%; 64.8%; P  = 0.3). The mitral gradient showed a significant reduction (11 mmHg; 6 mmHg; P  < 0.001). Residual mitral regurgitation was not present. There was no left ventricular outflow tract obstruction. Conclusions The mitral ViV implant in a failed bioprosthesis is an effective procedure. This possibility might alter prosthesis selection in the future initial surgical prosthesis selection, favouring bioprostheses. Further large trials should explore its safety.