Early Six-Minute Walk Test May Predict Midterm Outcomes Following Coronary Artery Bypass Grafting

ABSTRACT Objective: This study aims to investigate the ability of the six-minute walk distance (6MWD) as a prognostic marker for midterm clinical outcomes three months after coronary artery bypass grafting (CABG), to identify possible predictors of fall in 6MWD in the early postoperative period, and to establish the percentage fall in early postoperative 6MWD, considering the preoperative baseline as 100%. Methods: A prospective cohort of patients undergoing elective CABG were included. The percentage fall in 6MWD was assessed by the difference between preoperative and postoperative day (POD) five. Clinical outcomes were evaluated three months after hospital discharge. Results: There was a significant decrease in 6MWD on POD5 compared with preoperative baseline values (percentage fall of 32.5±16.5%, P<0.0001). Linear regression analysis showed an independent association of the percentage fall of 6MWD with cardiopulmonary bypass (CPB) and preoperative inspiratory muscle strength. Receiver operating characteristic curve analysis revealed that the best cutoff value of percentage fall in 6MWD to predict poorer clinical outcomes at three months was 34.6% (area under the curve = 0.82, sensitivity = 78.95%, specificity = 76.19%, P=0.0001). Conclusion: This study indicates that a cutoff value of 34.6% in percentage fall of 6MWD on POD5 was able to predict poorer clinical outcomes at three months of follow-up after CABG. Use of CPB and preoperative inspiratory muscle strength were independent predictors of percentage fall of 6MWD in the postoperative period. These findings further support the clinical application of 6MWD and propose an inpatient preventive strategy to guide clinical management over time.

Inspiratory Muscle Weakness is Related to Poor Short-Term Outcomes for Heart Transplantation

Abstract Introduction: In heart transplantation (HT) recipients, several factors are critical to promptly adopting appropriate rehabilitation strategies and may be important to predict outcomes way after surgery. This study aimed to determine preoperative patient-related risk factors that could adversely affect the postoperative clinical course of patients undergoing HT. Methods: Twenty-one hospitalized patients with heart failure undergoing HT were evaluated according to respiratory muscle strength and functional capacity before HT. Mechanical ventilation (MV) time, reintubation rate, and intensive care unit (ICU) length of stay were recorded, and assessed postoperatively. Results: Inspiratory muscle strength as absolute and percentpredicted values were strongly correlated with MV time (r=-0.61 and r=-0.70, respectively, at P<0.001). Concerning ICU length of stay, only maximal inspiratory pressure (MIP) absolute and percent-predicted values were significantly associated. The absolute -MIP- was significantly negatively correlated with ICU length of stay (r=-0.58 at P=0.006) and the percent-predicted MIP was also significantly negatively correlated with ICU length of stay (r=-0.68 at P=0.0007). No associations were observed between preoperative functional capacity, age, sex, and clinical characteristics and MV time and ICU length of stay in the cohort included in this study. Patients with respiratory muscle weakness had a higher prevalence of prolonged MV, reintubation, and delayed ICU length of stay. Conclusion: An impairment of preoperative MIP was associated with poorer short-term outcomes following HT. As such, inspiratory muscle strength is an important clinical preoperative marker in patients undergoing HT.

Cardiovascular involvement in COVID-19: not to be missed

Abstract In December 2019, a striking appearance of new cases of viral pneumonia in Wuhan led to the detection of a novel coronavirus (SARS-CoV2). By analyzing patients with severe manifestations, it became apparent that 20 to 35% of patients who died had preexisting cardiovascular disease. This finding warrants the important need to discuss the influence of SARS-CoV2 infection on the cardiovascular system and hemodynamics in the context of clinical management, particularly during mechanical ventilation. The SARS-CoV2 enters human cells through the spike protein binding to angiotensin-converting enzyme 2 (ACE2), which is important to cardiovascular modulation and endothelial signaling. As ACE2 is highly expressed in lung tissue, patients have been progressing to acute respiratory injury at an alarming frequency during the Coronavirus Disease (COVID-19) pandemic. Moreover, COVID-19 leads to high D-dimer levels and prothrombin time, which indicates a substantial coagulation disorder. It seems that an overwhelming inflammatory and thrombogenic condition is responsible for a mismatching of ventilation and perfusion, with a somewhat near-normal static lung compliance, which describes two types of pulmonary conditions. As such, positive pressure during invasive mechanical ventilation (IMV) must be applied with caution. The authors of this review appeal to the necessity of paying closer attention to assess microhemodynamic repercussion, by monitoring central venous oxygen saturation during strategies of IMV. It is well known that a severe respiratory infection and a scattered inflammatory process can cause non-ischemic myocardial injury, including progression to myocarditis. Early strategies that guide clinical decisions can be lifesaving and prevent extended myocardial damage. Moreover, cardiopulmonary failure refractory to standard treatment may necessitate the use of extreme therapeutic strategies, such as extracorporeal membrane oxygenation.

Valve heart surgery in Brazil - the bypass registry analysis

Abstract Objective: To analyze the profile and outcomes of patients who underwent valve heart surgery in Brazil, using information retrieved from the Brazilian Registry of Cardiovascular Surgeries in Adults (BYPASS Registry) database. Methods: This is a multicenter cohort study, evaluating 920 patients submitted to heart valve surgery. Demographics and postoperative clinical outcomes were assessed and compared to estimate mortality risk using the European System for Cardiac Operative Risk Evaluation (EuroSCORE). Results: Isolated aortic valve replacement was the most frequently performed surgery (34%), followed by isolated mitral valve replacement (24.9%). Valve repair was performed in 21% of mitral procedures. Minimally invasive access was performed in 1.6% and the most frequent postoperative complications were arrhythmias (22.6%), infections (5.7%), and low-output syndrome (5.1%). Operations covered by the public health system accounted for 80.8% and the hospital mortality rate was 7.3%. Conclusion: The most frequent isolated valve surgery in Brazil is the aortic valve replacement by conventional open access and the rheumatic disease is still the main etiology for valve surgery. The BYPASS Registry has a fundamental role to provide information on the profile of patients with valve heart disease in our country in order to delineate adequate strategies for health promotion and resource allocation for cardiac surgery.

A dedicated stitch to allow early safe mobilization avoiding drain-induced heart injury

Abstract Placement of a mediastinal drain is a routine procedure following heart surgery. Postoperative bed rest is often imposed due to the fear of potential risk of drain displacement and cardiac injury. We developed an encapsulating stitch as a feasible, effective and low-cost technique, which does not require advanced surgical skills for placement. This simple, novel approach compartmentalizes the drain allowing for safe early mobilization following cardiac surgery.

Hemodynamic changes during heart displacement in aorta no-touch off-pump coronary artery bypass surgery: a pilot study

Abstract Objective: To evaluate the sequential changes of hemodynamic and metabolic parameters in patients who underwent aorta no-touch off-pump coronary artery bypass surgery (OPCAB). Methods: Prospective study involving twenty-seven consecutive patients who underwent aorta no-touch OPCAB. The FloTrac/PreSep/Vigileo™ system (Edwards Lifesciences) was used to continuously record heart rate (HR), mean arterial blood pressure (MABP), central venous pressure (CVP), continuous cardiac index (FCI), stroke volume (SV), stroke volume variation (SVV), and central venous oxygen saturation (ScvO2). The parameters were assessed 5 min before, during and 5 min after each anastomosis (left anterior descending [LAD], posterior descending [PD], obtuse marginal [OM] and diagonal [Dg]). Postoperative lactate was also evaluated. Results: There was no significant change in HR and MABP for all anastomoses, except for MABP during PD grafting (-10.1±2.7 mmHg, P=0.03). There was a significant decrease in ScvO2 only during PD and OM anastomoses (-9.4±0.4, P=0.03; -4.4±0.4, P=0.02; respectively). CVP drop after PD manipulation was strongly associated with a higher lactate during the first hours after surgery (r=-0.82; P=0.001). These hemodynamic changes were transient and entirely recovered after the heart was returned to its anatomical position. No significant differences were observed in FCI, SVV, or the systemic vascular resistance index (SVRI) during all anastomoses, except for a drop in SVRI during PD grafting (-8.03±2.3, P=0.007). SV tended to decrease during the procedure in all territories, but with statistically significant drop only in PD and OM grafting (-10.4±1.2, P=0.02; -13.6±5.1, P=0.007; respectively). Conclusion: Heart displacement for performing aorta no-touch OPCAB is well tolerated, with transient and endurable hemodynamic variations.

Early open-lung ventilation improves clinical outcomes in patients with left cardiac dysfunction undergoing off-pump coronary artery bypass: a randomized controlled trial

Abstract Objective: To compare pulmonary function, functional capacity and clinical outcomes amongst three groups of patients with left ventricular dysfunction following off-pump coronary artery bypass, namely: 1) conventional mechanical ventilation (CMV); 2) late open lung strategy (L-OLS); and 3) early open lung strategy (E-OLS). Methods: Sixty-one patients were randomized into 3 groups: 1) CMV (n=21); 2) L-OLS (n=20) initiated after intensive care unit arrival; and 3) E-OLS (n=20) initiated after intubation. Spirometry was performed at bedside on preoperative and postoperative days (PODs) 1, 3, and 5. Partial pressure of arterial oxygen (PaO2) and pulmonary shunt fraction were evaluated preoperatively and on POD1. The 6-minute walk test was applied on the day before the operation and on POD5. Results: Both the open lung groups demonstrated higher forced vital capacity and forced expiratory volume in 1 second on PODs 1, 3 and 5 when compared to the CMV group (P<0.05). The 6-minute walk test distance was more preserved, shunt fraction was lower, and PaO2 was higher in both open-lung groups (P<0.05). Open-lung groups had shorter intubation time and hospital stay and also fewer respiratory events (P<0.05). Key measures were significantly more favorable in the E-OLS group compared to the L-OLS group. Conclusion: Both OLSs (L-OLS and E-OLS) were able to promote higher preservation of pulmonary function, greater recovery of functional capacity and better clinical outcomes following off-pump coronary artery bypass when compared to conventional mechanical ventilation. However, in this group of patients with reduced left ventricular function, initiation of the OLS intra-operatively was found to be more beneficial and optimal when compared to OLS initiation after intensive care unit arrival.

A cycle ergometer exercise program improves exercise capacity and inspiratory muscle function in hospitalized patients awaiting heart transplantation: a pilot study

Abstract Objective: The purpose of this study was to evaluate the effect of a cycle ergometer exercise program on exercise capacity and inspiratory muscle function in hospitalized patients with heart failure awaiting heart transplantation with intravenous inotropic support. Methods: Patients awaiting heart transplantation were randomized and allocated prospectively into two groups: 1) Control Group (n=11) - conventional protocol; and 2) Intervention Group (n=7) - stationary cycle ergometer exercise training. Functional capacity was measured by the six-minute walk test and inspiratory muscle strength assessed by manovacuometry before and after the exercise protocols. Results: Both groups demonstrated an increase in six-minute walk test distance after the experimental procedure compared to baseline; however, only the intervention group had a significant increase (P =0.08 and P =0.001 for the control and intervention groups, respectively). Intergroup comparison revealed a greater increase in the intervention group compared to the control (P <0.001). Regarding the inspiratory muscle strength evaluation, the intragroup analysis demonstrated increased strength after the protocols compared to baseline for both groups; statistical significance was only demonstrated for the intervention group, though (P =0.22 and P <0.01, respectively). Intergroup comparison showed a significant increase in the intervention group compared to the control (P <0.01). Conclusion: Stationary cycle ergometer exercise training shows positive results on exercise capacity and inspiratory muscle strength in patients with heart failure awaiting cardiac transplantation while on intravenous inotropic support.