Elaine Soraya Barbosa de Oliveira Severino

Six-minute walk test as a tool for assessing the quality of life in patients undergoing coronary artery bypass grafting surgery

OBJECTIVE To assess the quality of life in patients undergoing myocardial revascularization using the six-minute walk test. METHODS Prospective observational study with patients who undergoing CABG. The clinical variables, the sixminute walk test, and the SF-36 test were recorded. The patients were assessed at the preoperative time and at 2 months of postoperative period. According their six-minute walk test results, the patients were divided into two groups: group walked more than 350 meters (> 350 meters Group) and the group walked less than 350 meters (< 350 meters Group) at the preoperative time. RESULTS Eight-seven patients were included. Age was comparable in both groups (59 ± 9.5 years vs. 61 ± 9.3 years; respectively, P = 0.24). The group walked > 350 meters distance was higher than the < 350 meters group after 2 months of operation (436 ± 78 meters vs. 348 ± 87 meters; P <0.01). The quality of life was lower in the < 350 meters group compared to the > 350 meters group in the preoperative period in the following domains: functional capabilities, limitations due to physical aspects, overall health feelings, vitality, and social aspects. Quality of life improved after two months in both groups. CONCLUSIONS The six-minute walk test at the preoperative time is associated with the quality of life after two months of coronary artery bypass grafting. In overall, quality of life has improved in all patients. The improvement in the quality of life was greater in those patients who walked distances lower than 350 meters at the preoperative time.

Resultados tardios da plastia mitral em pacientes reumáticos

INTRODUCTION AND AIMS The long-term results after surgical repair of rheumatic mitral valve remain controversial in literature. Our aim was to determine the predictive factors which impact the long-term results after isolated rheumatic mitral valve repair and to evaluate the effect of those factors on reoperation and late mortality. METHODS One hundred and four patients with rheumatic valve disease who had undergone mitral valve repair with or without tricuspid valve annuloplasty were included. All patients with associated procedures were excluded. The predictive variables for reoperation were assessed with Cox regression and Kaplan Meier survival curves. RESULTS The mean follow-up time was 63 ± 39 months (CI 95% 36 to 74 months). The functional class III and IV was observed in 65.4% of all patients. The posterior ring annuloplasty was performed in 33 cases, comissutoromy in 21 cases, and comissurotomy with posterior ring annuloplasty in 50 patients. There was no operative mortality. The late mortality was 2.8% (three patients). The late reoperation was associated with residual mitral valve regurgitation after surgery (P<0.001), pulmonary hypertension at the pre-operative time (P<0.001), age (P<0.04) and functional class at the post-operative time (P<0.001). We observed freedom from reoperation rates at 5 and 10 years of 91.2 ± 3.4% and 71.1 ± 9.2%, respectively. CONCLUSION Repair of mitral valve in rheumatic valve disease is feasible with good long-term outcomes. Preoperative pulmonary hypertension, residual mitral valve regurgitation after surgery, age and functional class are predictors of late reoperation.

The effects of modified ultrafiltration on pulmonary function and transfusion requirements in patients underwent coronary artery bypass graft surgery.

OBJECTIVE The inflammatory response after cardiac surgery increases vascular permeability leading to higher mortality and morbidity in the post operative time. The modified ultrafiltration (MUF) had shown benefits on respiratory, and hemodynamic in pediatric patients. This approach in adults is not well established yet. We hypothesize that modified ultrafiltration may improve respiratory, hemodynamic and coagulation function in adults after cardiac surgeries. METHODS A prospective randomized study was carried out with 37 patients who underwent coronary artery bypass graft surgery (CABG) were randomized either to MUF (n=20) at the end of bypass or to control (no MUF) (n=17). The anesthesia and ICU team were blinded for the group selection. The MUF were carried out for 15 minutes after the end of bypass. The patients data were taken at beginning of anesthesia, ending of bypass, ending MUF, 24 hours, and 48 hours after surgery. For clinical outcome the pulmonary, hemodynamic and coagulation function were evaluated. RESULTS We observed lower drain loss in the MUF group compared to control group after 48 hours (598 +/- 123 ml vs. 848 +/- 455 ml; P=0.04) and required less red blood cells units transfusion compared to control group (0.6 +/- 0.6 units/patient vs.1.6 +/- 1.1 units/patient; P=0.03). The MUF group showed lower airway resistance (9.3 +/- 0.4 cmH2O.L-1s-1 vs. 12.1 +/- 0.8 cmH2O.L-1s-1; P=0.04). There were no deaths in both groups. CONCLUSION The MUF reduces post operatory bleeding and red blood cells units transfusion, but with no differences on clinical outcome were observed. The routinely MUF employment was not associated with hemodynamic instability.

Associated factors with survivals in patients undergoing orthotopic heart transplant using retrograde blood microcardioplegia

BACKGROUND Several techniques and cardioplegic solutions have been used for heart preservation during transplant procedures. Unfortunately, there is a lack of ideal method for myocardial preservation in the clinical practice. The use of retrograde cardioplegia provides continuous infusion of cardioplegic solution during the graft implantation. This strategy may provide better initial recovery of the graft. The objective of this study is to describe the experience of a single center where all patients received the same solution for organ preservation and were subjected to continuous retrograde blood microcardioplegia during implantation of the graft and to evaluate factors associated to early and late mortality with this technique. METHODS This is a retrospective, observational and descriptive study of a single center. RESULTS During the study period were performed 35 heart transplants. Fifteen (42.9%) patients were in cardiogenic shock. The probability of survival was 74.8±7.8%, 60.4±11.3% and 15.1±13.4% at 1 year, 5 years and 10 years of follow-up, respectively. The median survival time was 96.6 months. CONCLUSION The use of myocardial protection with retrograde cardioplegic solution may reduce the risks associated morbidity due to cold ischemia time during the heart transplant, and we suggest that this benefit may be even greater in cases of cold ischemia time longer ensuring protection to the myocardium.

The influence of the residual stress in silicone tubes in the calibration methods of roller pumps used in cardiopulmonary bypass.

The rotation of rollers in cardiopulmonary bypass pumps propels the blood through various devices to reach the patient. Very occlusive settings may squeeze red blood cells, whereas a nonocclusive setting may result in retrograde flow. Occlusion of roller pumps may be regulated either by measuring the drop rate or by dynamic calibration. This study evaluated the influence of silicone tubing residual stress found on pump regulation. Silicone tubes obtained from two different suppliers were used in 6-inch DeBakey roller pumps. The variations occurring over time in the measurements of drop rate, dynamic calibration, and tube residual stress were analyzed. Covariance analysis of the four linear regressions has shown a progressive and accentuated reduction in drop rate (p < 0.002). It is noticeable that the angular coefficients of the drop rate measurements of the four silicone tubes are the same (p > 0.56). This reduction in drop rate measurements may affect the regulation of the pumps before surgical procedures. One probable cause for this reduction is the residual stress found in the silicone tubes. Settings based on the dynamic calibration process tended to be repeated over time. Simple linear regression test (angular coefficient equals zero) has shown a p > 0.79 showing no interference of the silicone tubes residual stress on dynamic calibration, suggesting that one should use this method to calibrate roller pumps.

Characterization of both myocardial extracellular volume expansion and myocyte hypertrophy by CMR in heart transplantation recipients without active rejection: implications for early cardiac remodeling

Background Left ventricular hypertrophy (LVH) after heart transplant (HTx) is multifactorial, associations include hypertension, chronic immune injury and the intrinsic effects of immunosuppression. Its consequences are significant and potentially provide an explanation for the development of diastolic dysfunction and exercise intolerance, as well as the limited life expectancy after HTx. Both expansion of myocardial extracellular volume (ECV) and myocyte hypertrophy (MH) coexist in this setting. Cardiac biopsies have limitations and may be non-representative to assess global myocardial remodeling. The goal of this pilot study was to characterize both ECV and MH by CMR in cohort of HTx recipients without active rejection. Methods T1 relaxation times were measured before and after gadolinium contrast. The intracellular lifetime of water (τic), a cell size-dependent parameter, and extracellular volume fraction, a marker of interstitial fibrosis, were determined with a model for transcytolemmal water exchange. Results Nineteen HTx recipients (mean age 50±0, 6 female, BSA 1,70±0,16m 2 , median follow-up after HTx 11±13 months) without acute rejection and 20 age matched health volunteers (mean age 51±14) underwent CMR (1.5T) includingmeasurement of LV function, T2, T1 mapping pre- and post-gadolinium and LGE, and a echocardiogram for measurement of diastolic function. HTx recipients demonstrated normal LVEF (68±11%) with a significant increased in LVMass in comparison with age-matched volunteers (LVMass 114±19g vs. 80±5g; p<0.05). Both groups (HTx and controls) did not show LGE or abnormal signal intensity in T2 images. ECV was substantially higher in HTx patients (0,43 ±0,14) compared with volunteers (0.29±0.03, p<0.0001). Both ECV, a marker of interstitial fibrosis, and τic ,a new validated maker of myocyte hypertrophy, were significantly associated with LV mass (r=0.72 and r=0.68 respectively , both p<0.05). ECV and τic also demonstrated a strong association with E wave deceleration time (EDT) by TTE (r=0.77 and 0.74 respectively, both p<0.05). ECV maintained the positive association with EDT indexed to E wave. (r=0.66, p<0.01). by ROC curve analysis, the ECV was able to predict diastolic dysfunction using EDT by ETT with AUC 0.97 (ECV cut value 0.37, Sens 100%, Spec 86%, p<0.01).

Ventricular pacing threshold after transthoracic external defibrillation with two different waveforms: an experimental study

AIMS Although an increase in the ventricular pacing threshold (VPT) has been observed after administration of transthoracic shock for ventricular defibrillation, few studies have evaluated the phenomenon with respect to the defibrillation waveform energy. Therefore, this study examined the VPT behaviour after transthoracic shock with a monophasic or biphasic energy waveform. METHOD AND RESULTS Domestic Landrace male piglets implanted with a permanent pacemaker stimulation system were divided into three groups: no ventricular fibrillation (VF) induction and transthoracic shock with monophasic or biphasic energy (group I); VF induction, 1 min of observation without intervention, 2 min of external cardiac massage, and transthoracic shock with monophasic or biphasic energy (group II); and VF induction, 2 min of observation without intervention, 4 min of external cardiac massage, and transthoracic shock with monophasic or biphasic energy (group III). After external shock, the VPT was evaluated every minute for 10 min. A total of 143 experiments were performed. At the end of the observation period, groups I and II showed steady VPT values. Group III showed an increase in VPT with monophasic or biphasic external energy, with no difference between the external energy sources. The monophasic but not the biphasic waveform was associated with higher VPT values when the VF was longer. CONCLUSION Defibrillation does not have a significant impact on pacing threshold, but a longer VF period is related to a higher VPT after defibrillation with monophasic waveform.

Flow visualization in blood aspirator and cardiotomy reservoir used in cardiopulmonary bypass

OBJECTIVE One of the major damage caused by occlusion in roller pumps is hemolysis. Comparative studies between roller pump with adjustments non occlusive and centrifugal pumps have been made in recent decades in an attempt to develop new products and adjustments that cause fewer traumas to the figurative elements of blood. Usually the roller pumps are adjusted by the static method due to concern variables flow that can occur with non-occlusive settings. Excessive slack in the rollers provoke back flow and can provides errors in the calculation of flow by the rotation of the pump, according to the devices added to the circuit and the systemic resistance of the patient. The objective of this study is to evaluate the back flow caused by two types of roller pumps in blood aspirator and cardiotomy reservoir. METHOD Back flow visualization was performed in blood aspirator and cardiotomy reservoir. It was tested two different models of roller pumps, adjusted by drop rate and dynamic calibration. The tests were conducted with silicone tubes of 3/8 x 1/16 e 1/2 x 3/32 inches in diameter in water and solution similar to blood. RESULTS We recorded back flow visually in blood aspirator and in cardiotomy reservoir with their measure of values. The pumps had differences in refluxes measured adjusted by the dynamic calibration method. Pump#2 presents back flow adjusted fully occluded. CONCLUSION The back flow measured in two models of pump present differences (P <0.008). The results indicate differences in its characteristics caused by the process of manufacturing, design or possible wear. Non-occlusive adjustments may cause variations in flow with the increase of resistance added to the circuit, with difficulty to fix the flow by increasing the rotation.