Relationship between echocardiographic index of ventricular filling pressure and intraoperative haemodynamic changes during off-pump coronary bypass surgery

Inhaled iloprost in off-pump coronary artery bypass surgery: a randomized controlled trial

PURPOSE

Mechanical cardiac constraint during off-pump coronary artery bypass surgery (OPCAB) causes right ventricle (RV) compression and increased pulmonary artery pressure (PAP), which may further compromise RV dysfunction. We aimed to assess the effect of inhaled iloprost, a potent selective pulmonary vasodilator, on the cardiac index (CI) during mechanical constraint. The secondary aim was to determine the resultant changes in the hemodynamic and respiratory parameters.

METHODS

A total of 100 adult patients with three-vessel coronary artery disease who had known risk factors for hemodynamic instability (congestive heart failure, mean PAP ≥ 25 mm Hg, RV systolic pressure ≥ 50 mm Hg on preoperative echocardiography, left ventricular ejection fraction < 50%, myocardial infarction within one month of surgery, redo surgery, and left main disease) were enrolled in a randomized controlled trial. The patients were randomly allocated to the control or iloprost groups at a 1:1 ratio, in which saline and iloprost (20 μg) were inhaled for 15 min after internal mammary artery harvesting, respectively. Cardiac index was measured by pulmonary artery catheterization.

RESULTS

There were no significant intergroup differences in CI during grafting (P = 0.36). The mean PAP had a significant group-time interaction (P = 0.04) and was significantly lower in the iloprost group at circumflex grafting (mean [standard deviation], 26 [3] mm Hg vs 24 [3] mm Hg; P = 0.01). The remaining hemodynamic parameters were similar between the groups.

CONCLUSION

Inhaled iloprost showed a neutral effect on hemodynamic parameters, including the CI and pulmonary vascular resistance index, during OPCAB.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT04598191); first submitted 12 October 2020.

Peri-operative changes in diastolic function and outcomes in congenital aortic valve surgery

Background

The ratio of early diastolic mitral inflow velocity (E) to early diastolic mitral annular tissue velocity (e’), or E/e’, is an echocardiographic measure of left ventricular filling pressure. Peri‐operative changes in E/e’ and association with outcomes have been demonstrated in adults undergoing surgery for aortic stenosis (AS). We sought to explore changes in E/e’ and other diastolic indices in the setting of congenital AS surgery and to assess for association with post‐operative outcomes among children and young adults.

Methods

A retrospective, single‐center study was performed among patients 6 months to 30 years of age who underwent congenital AS surgery from 2006 to 2018. Tissue Doppler indices were collected from pre‐ and post‐operative echocardiograms. Post‐operative outcomes were reviewed.

Results

Sixty‐six subjects with subvalvar (45%), valvar (47%), and supravalvar (8%) AS underwent surgery at a median age of 9.5 years (IQR: 4.0–14.8). Pre‐operatively, the lateral E/e’ ratio was 8.6 (6.7–11.0); 33% had E/e’≥10. Post‐operatively, the lateral e’ decreased to 9.9 cm/s (8.0–11.4), the E/e’ ratio increased to 10.4 (8.3–13.1); and 53% had E/e’≥10 (p‐values < 0.0001, 0.0072, and < 0.001, respectively). Pre‐operative lateral e’ correlated modestly with duration of intubation (ρ = −0.24, p‐value 0.048) and post‐operative lateral e’ correlated modestly with duration of intubation and length of hospital stay (ρ = −0.28 and −0.26, p‐values = 0.02 and 0.04, respectively).

Conclusions

Children and young adults who underwent congenital AS surgery had echocardiographic evidence of diastolic dysfunction pre‐operatively that worsened post‐operatively. Lateral e’ may be a sensitive indicator of impaired ventricular relaxation in these patients and may impact duration of intubation and hospital stay.

Euvolemic off pump coronary surgery further improves early postoperative outcomes

Background:

Fluid resuscitation during Off-Pump Coronary Surgery (OPCABG) is still not protocolized and depends on multiple variables. We are exploring in this study whether a restrictive or euvolemic approach has any impact on short term surgical outcomes following OPCABG.

Methods:

It is a retrospective study of 300 patients analyzed based on the intraoperative fluid requirement with 150 patients in each group (Group I: Fluid <2 Litres, Group II: Fluid >2 Litres).

Results:

Multivariable analysis showed echocardiography variables such as E/e ratio, LA volume index, and atrial fibrillation (AF). LA volume index is related to the higher fluid requirement. Group II had significantly higher ventilation time (P < 0.05), drain output (P = 0.05), drain removal time (<0.05), inotropic requirement, and diuretic use.

Conclusion:

The requirement of the intraoperative fluid was associated with various factors including diastolic dysfunction (left atrial volume index, left ventricle mass index, E/e ratio) and preoperative dual antiplatelet use. Group II patients had longer ventilation time, diuretics use, high drain output, and required drains for a longer period of time. Although there was no statistical difference among two groups as far as postoperative AF concerned, a reversal of AF to sinus rhythm was delayed in group II patients.

Perioperative Echocardiographic Index of Left Ventricular Filling Pressure in Cardiac Surgery

BACKGROUND

The elevated preoperative ratio of early transmitral flow velocity to early diastolic velocity of the mitral annulus (E/e') as an echocardiographic index of left ventricular filling pressure is known to be associated with poor postoperative outcomes. We investigated the association between preoperative and postoperative E/e' elevation and clinical outcomes after cardiac operations.

METHODS

The study divided 1,353 patients who underwent cardiac operations into four groups: preoperative and postoperative E/e' ≤15 (low-low), preoperative E/e' ≤15 but postoperative E/e' >15 (low-high), preoperative E/e' >15 but postoperative E/e' ≤15 (high-low), and preoperative and postoperative E/e' >15 (high-high). Cox proportional hazard analysis was performed. Kaplan-Meier curve analysis was performed before and after propensity score matching.

RESULTS

The four perioperative E/e' categories were independently associated with 5-year mortality (hazard ratio, high-high vs low-low: 3.58; low-high vs low-low: 3.75; high-low vs low-low: 1.18). Kaplan-Meier curves showed that mortality was significantly different between the groups (log-rank test: high-high vs. low-low, p < 0.001; low-high vs low-low, p < 0.001). Postoperative intensive care unit and hospital lengths of stay, incidence of acute kidney injury, and 1-year mortality were significantly different. However, after propensity score matching, mortality and the incidence of postoperative acute kidney injury were significantly different only between postoperative E/e' ≤15 and E/e' >15, but not between preoperative E/e' ≤15 and E/e' >15.

CONCLUSIONS

Postoperative E/e' >15 was more strongly associated with mortality and acute kidney injury than preoperative E/e' >15. Measurement of the postoperative E/e' ratio may help in assessing the risk of these patients.

Association Between Elevated Echocardiographic Index of Left Ventricular Filling Pressure and Acute Kidney Injury After Off-Pump Coronary Artery Surgery

BACKGROUND

The ratio of the early transmitral flow velocity to early diastolic velocity of the mitral annulus (E/e') is an echocardiographic index of mean left ventricular (LV) filling pressure. We investigated the association between the preoperative E/e' ratio and postoperative acute kidney injury (AKI) during off-pump coronary artery bypass surgery (OPCAB).Methods and Results:We reviewed 585 patients who underwent OPCAB and with preserved LV ejection fraction determined by preoperative echocardiography. AKI was determined by the Kidney Disease Improving Global Outcomes (KDIGO) criteria. Multivariable logistic regression analysis was performed. E/e' was also analyzed as 3 categories (E/e' <8, 8≤E/e'≤15, and E/e' >15) and as a continuous variable. A propensity score analysis was used to match the patients with E/e' >15 and E/e' ≤15. A preoperative E/e' >15 was an independent predictor for AKI (odds ratio 3.01, 95% confidence interval 1.40-6.17). E/e' >15 was also an independent predictor for AKI when E/e' was analyzed with 3 categories or as a continuous variable. In the matched sample, the incidence of AKI and 1-year mortality was significantly higher in patients with E/e' >15.

CONCLUSIONS

Among patients undergoing OPCAB with preserved LV systolic function, a preoperative E/e' ratio >15 was an independent predictor of postoperative AKI. Measurement of the preoperative E/e' ratio may help to assess the risk of postoperative AKI.

Monitoring diastolic dysfunction using a simplified algorithm in patients undergoing off-pump coronary artery bypass grafting surgery

Context:

Left ventricle diastolic dysfunction (LVDD) is gaining importance as useful marker of mortality and morbidity in cardiac surgical patients. Different algorithms have been proposed for the intraoperative grading of DD. Knowledge of the particular grade of DD has clinical implications with the potential to modify therapy, but there is a paucity of literature on the role of diastolic function evaluation during off-pump coronary artery bypass grafting (OPCABG) surgery.

Aims:

The aim of this study was to monitor changes in LVDD using simplified algorithm proposed by Swaminathan et al. in patients undergoing OPCABG.

Settings and Design:

The study was conducted in a tertiary care level hospital; this was a prospective, observational study.

Subjects and Methods:

Fifty consecutive patients undergoing OPCABG were enrolled. Hemodynamic and echocardiographic parameters were measured at 6 stages in every patient namely after anesthetic induction (baseline), during left internal mammary artery (LIMA) to left anterior descending (LAD) grafting (LIMA → LAD), saphenous vein graft (SVG) to obtuse marginal (OM) grafting (SVG → OM), SVG to posterior descending artery (PDA) grafting (SVG → PDA), during proximal anastomosis of SVG to aorta, and postprotamine. The patients were classified in grades of LVDD as per simplified algorithm proposed by Swaminathan et al. using only intraoperatively measured E and E’.

Results:

The success rate of measurement and classification of LVDD was 98.92% (277 out of 280 measurements). The grades of LVDD varied significantly as per surgical steps with maximum downgrading occurring during OM and LAD grafting. During OM grafting, none of the patients had normal diastolic function while 29% of patients exhibited restrictive pattern (Grade 3 LVDD). Patients with normal baseline LV diastolic function also exhibited downgrading during OM and LAD grafting. Postprotamine, 37% of patients with normal baseline diastolic function continued to exhibit some degree of DD.

Conclusions:

The LVDD changes dynamically during various stages of OPCABG, which can be successfully monitored with simplified algorithm.

Predictive Value of Echocardiographic Abnormalities and the Impact of Diastolic Dysfunction on In-hospital Major Cardiovascular Complications after Living Donor Kidney Transplantation

Patients with end-stage renal disease (ESRD) show characteristic abnormalities in cardiac structure and function. We evaluated the influence of these abnormalities on adverse cardiopulmonary outcomes after living donor kidney transplantation in patients with valid preoperative transthoracic echocardiographic evaluation. We then observed any development of major postoperative cardiovascular complications and pulmonary edema until hospital discharge. In-hospital major cardiovascular complications were defined as acute myocardial infarction, ventricular fibrillation/tachycardia, cardiogenic shock, newly-onset atrial fibrillation, clinical pulmonary edema requiring endotracheal intubation or dialysis. Among the 242 ESRD study patients, 9 patients (4%) developed major cardiovascular complications, and 39 patients (16%) developed pulmonary edema. Diabetes, ischemia-reperfusion time, left ventricular end-diastolic diameter (LVEDd), left ventricular mass index (LVMI), right ventricular systolic pressure (RVSP), left atrium volume index (LAVI), and high E/E' ratios were risk factors of major cardiovascular complications, while age, LVEDd, LVMI, LAVI, and high E/E' ratios were risk factors of pulmonary edema. The optimal E/E' cut-off value for predicting major cardiovascular complications was 13.0, showing 77.8% sensitivity and 78.5% specificity. Thus, the patient's E/E' ratio is useful for predicting in-hospital major cardiovascular complications after kidney transplantation. We recommend that goal-directed therapy employing E/E' ratio be enacted in kidney recipients with baseline diastolic dysfunction to avert postoperative morbidity. (http://Clinical Trials.gov number: NCT02322567).

Impact of intraoperative hyperglycaemia on renal dysfunction after off-pump coronary artery bypass

OBJECTIVES

Acute kidney injury (AKI) is one of the most frequently occurring complications after off-pump coronary artery bypass graft (OPCAB). Hyperglycaemia is a major, potentially modifiable risk factor of adverse outcome after cardiac surgery known to aggravate organ damage. The aim of this study was to address the association between intraoperative glucose concentration and postoperative AKI in patients who underwent OPCAB.

METHODS

The medical records of 880 consecutive patients were retrospectively reviewed. Patients were divided into three groups according to the time-weighted average of intraoperative glucose concentrations (<110, 110-150 and >150 mg/dl), and the incidence of AKI (increase of serum creatinine to >2.0 mg/dl and 2 × most recent preoperative value or a new requirement for dialysis) was compared. Multivariate logistic regression analysis was performed to identify independent risk factors for postoperative AKI.

RESULTS

The incidence of AKI was higher in patients with a glucose level >150 mg/dl than in patients with a glucose level = 110-150 mg/dl [8% (20 of 251) vs 3% (14 of 453), P = 0.004]. On multivariate analysis, glucose >150 mg/dl (odds ratio [OR], 2.78; 95% confidence interval [CI], 1.12-6.86, P = 0.027), coefficient of variation of glucose (OR, 1.04; 95% CI, 1.01-1.07, P = 0.027) and preoperative serum creatinine >1.4 mg/dl (OR, 8.81; 95% CI, 3.90-19.9, P < 0.001) were identified as independent risk factors for postoperative AKI.

CONCLUSIONS

Intraoperative glucose concentration >150 mg/dl and increased variability of glucose were independently associated with AKI after OPCAB. Tight intraoperative glycaemic control (<110 mg/dl) does not seem to provide additional benefit in terms of AKI.

Cardiac displacement-induced hemodynamic instability during off-pump coronary artery bypass surgery and its predictors

BACKGROUND

Emergent conversion to an on-pump procedure during an off-pump coronary artery bypass surgery (OPCAB) due to hemodynamic instability is associated with increased morbidity and mortality. The aim of this study was to evaluate the predictors of hemodynamic instability associated with mechanical heart displacement during OPCAB and the fate of these patients.

METHODS

Data of 494 patients who underwent elective, isolated OPCAB between December 2006 and April 2010 were reviewed. Hemodynamic instability was defined as mixed venous oxygen saturation (SvO(2) ) <60% during grafting. Pre-operative variables including the presence of diastolic dysfunction and mitral regurgitation (MR) were evaluated for their predictive value for hemodynamic instability by logistic regression analysis. Outcome variables were also compared between patients who developed hemodynamic instability and those who did not.

RESULTS

In univariate analysis, body mass index, diabetes mellitus, chronic obstructive pulmonary disease (COPD), left ventricular ejection fraction, diastolic dysfunction, MR ≥ grade 1, higher creatinine and the use of diuretics were identified as risk factors. In multivariate analysis of these variables, COPD and creatinine remained as independent risk factors for hemodynamic instability. These patients also had significantly lower cardiac output and SvO(2) after sternum closure and a higher incidence of composite morbidity end points.

CONCLUSION

COPD and pre-operative creatinine level were identified as independent risk factors of mechanical heart displacement-induced hemodynamic instability during OPCAB. As these patients were associated with significantly lower SvO(2) even at the end of surgery and with adverse outcome, consideration may be given to initiate preemptive measures to increase SvO(2) before or during grafting.

The effect of milrinone on the intraoperative hemodynamics during off-pump coronary bypass surgery in patients with an elevated echocardiographic index of the ventricular filling pressure

BACKGROUND

Hemodynamic derangement during off-pump coronary artery bypass surgery (OPCAB) is mainly attributed to impaired filling and diastolic dysfunction. An elevated ratio of the mitral velocity to the early-diastolic velocity of the mitral annulus (E/e' > 15) is a relatively new indicator of diastolic function, and this was reported to be associated with impaired hemodynamics during OPCAB. We investigated the efficacy of milrinone on the perioperative hemodynamics and short term outcomes of patients with an E/e' > 15 and who underwent OPCAB.

METHODS

The patients were randomly allocated into either group C (control, n = 31) or group M (n = 31) and they were treated with the same amount of either normal saline or milrinone (0.5 µg/kg/min) without bolus loading after completion of internal mammary artery harvest until the end of operation. Hemodynamic measurements were recorded after the induction of anesthesia (T1), 5 min after starting each distal anastomosis of the left anterior descending artery (T2), left circumflex artery (T3) and right coronary artery (T4), and 5 min after sternum closure (T5).

RESULTS

The mixed venous oxygen saturation (SvO(2)) was lower through T2-T4 compared to the baseline value in both groups, while the degree of the decrease was significantly less in group M than that in group C. The other hemodynamic variables, the operative data and the postoperative outcomes were similar between the two groups.

CONCLUSIONS

Intraoperative infusion of milrinone did not significantly improve the perioperative hemodynamics and the subsequent short term outcomes for the patients with preexisting diastolic dysfunction as represented by an elevated E/e' value, although it reduced the degree of decrease of the SvO(2) during OPCAB.

Focused Transthoracic Echocardiography in the Perioperative Period

Ultrasound applications in perioperative medicine have expanded enormously over the past decade. Transoesophageal echocardiography has been performed by anaesthetists during cardiac surgery for over 20 years. With the increasing availability of portable ultrasound systems, the use of ultrasound to assist in vascular cannulation and regional anaesthesia has been well described. Portable ultrasound systems come with a range of probes for different applications, including transthoracic echocardiography. While transthoracic echocardiography has traditionally been the domain of cardiologists, its use has been increasing in critical care, the emergency room and, recently, by anaesthetists in the perioperative period. Unlike formal cardiology-based transthoracic echocardiography, focused, goal-directed transthoracic echocardiography is often more appropriate in the perioperative period to address a particular question and can be performed in just a few minutes. Transthoracic echocardiography allows rapid, noninvasive, point-of-care assessment of ventricular function, valvular integrity, volume status and fluid responsiveness. It can help distinguish undifferentiated systolic murmurs preoperatively, give valuable information on the aetiology of unexplained hypotension and cardiovascular collapse and assess response to therapeutic interventions such as vasoactive drugs and volume resuscitation. Focused transthoracic echocardiography should include qualitative assessment of left and right ventricular function, an estimate of aortic valve gradient, right ventricular systolic pressure and intravascular volume status as minimum requirements. Transthoracic echocardiography is a valuable tool in the perioperative period and ideally the equipment and expertise should be available in all operating rooms.

Effect of aortic valve surgery on left ventricular diastole assessed by echocardiography and neuroendocrine response: percutaneous versus surgical approach

OBJECTIVES

Aortic valve implantation through peripheral vascular access is an option for high-risk patients with severe aortic valve stenosis. The authors aimed to compare the acute effect of endovascular and surgical aortic valve procedures on left ventricular diastolic function.

DESIGN

A case-matched, nonrandomized study.

SETTING

A university hospital.

PARTICIPANTS

Patients with aortic stenosis.

INTERVENTIONS

B-natriuretic peptide was measured in 30 patients with a logistic EuroSCORE > or =20% undergoing endovascular aortic valve implantation. Patients were case matched (age, mitral flow propagation velocity, mitral annulus early diastolic velocity, and B-natriuretic peptide measurement) with 30 control patients undergoing surgical aortic valve replacement through sternotomy. Left ventricular diastole was evaluated initially and after valve procedures with echocardiography by mitral flow propagation velocity and mitral annulus early diastolic velocity.

MEASUREMENTS AND MAIN RESULTS

B-natriuretic peptide was similar preoperatively in the 2 groups (346 [188-438] v 367 [211-458] pg/mL) and higher (p = 0.006) in the surgical group postoperatively (389.5 [237-479] v 710.5 [389-822] pg/mL), with a postprocedural statistically significant increase only in the surgical group. Diastolic function was similar in the 2 groups preoperatively, improved postoperatively in the endovascular group, and worsened in the surgical group.

CONCLUSIONS

B-natriuretic peptide increased after surgical but not after endovascular aortic valve replacement. Furthermore, endovascular aortic valve implantation acutely improved left ventricular diastolic function as documented by increases in mitral flow propagation velocity and mitral annulus early diastolic velocity.