Impaired right ventricular ejection fraction after cardiac surgery is associated with a complicated ICU stay

Right ventricular function in severe aortic stenosis assessed by echocardiography and MRI

BACKGROUND

The prevalence of aortic valve stenosis (AS) is increasing due to an ageing population. Despite that right ventricular function has prognostic value for postoperative outcome, the right ventricle (RV) is not extensively studied and often not routinely assessed in AS. Our aim was to explore the relation between severe AS and RV function in a surgical aortic valve replacement (SAVR) cohort, comparing two imaging modalities for RV evaluation.

METHODS

Patients with severe AS, underwent cardiovascular magnetic resonance imaging (CMR) and transthoracic echocardiography (TTE) before SAVR. RV dysfunction was defined as one or more of the following: tricuspid annular plane systolic excursion (TAPSE) < 17 mm, RV free wall strain (RVFWS) > -20% by TTE and RV ejection fraction (RVEF) <50% by CMR.

RESULTS

Sixteen (33%) patients were found to have RV dysfunction. Patients with RV dysfunction showed significantly lower indexed aortic valve area, left ventricular (LV) ejection fraction as well as RV and LV stroke volumes compared to patients with maintained RV function. All patients with reduced RVEF also had changes in TAPSE or RVFWS and a larger number of patients had a reduced longitudinal RV function despite a normal RVEF.

CONCLUSION

In a SAVR cohort one-third of the patients had RV dysfunction, defined by RVEF, TAPSE or RVFW strain. Echocardiography detected subtle changes in RV function before RVEF was reduced. It is likely that the more pronounced the AS, the more frequent the occurrence of RV dysfunction.

Epidemiology of perioperative RV dysfunction: risk factors, incidence, and clinical implications

In this edition of the journal, the Perioperative Quality Initiative (POQI) present three manuscripts describing the physiology, assessment, and management of right ventricular dysfunction (RVD) as pertains to the perioperative setting. This narrative review seeks to provide context for these manuscripts, discussing the epidemiology of perioperative RVD focussing on definition, risk factors, and clinical implications. Throughout the perioperative period, there are many potential risk factors/insults predisposing to perioperative RVD including pre-existing RVD, fluid overload, myocardial ischaemia, pulmonary embolism, lung injury, mechanical ventilation, hypoxia and hypercarbia, lung resection, medullary reaming and cement implantation, cardiac surgery, cardiopulmonary bypass, heart and lung transplantation, and left ventricular assist device implantation. There has however been little systematic attempt to quantify the incidence of perioperative RVD. What limited data exists has assessed perioperative RVD using echocardiography, cardiovascular magnetic resonance, and pulmonary artery catheterisation but is beset by challenges resulting from the inconsistencies in RVD definitions. Alongside differences in patient and surgical risk profile, this leads to wide variation in the incidence estimate. Data concerning the clinical implications of perioperative RVD is even more scarce, though there is evidence to suggest RVD is associated with atrial arrhythmias and prolonged length of critical care stay following thoracic surgery, increased need for inotropic support in revision orthopaedic surgery, and increased critical care requirement and mortality following cardiac surgery. Acute manifestations of RVD result from low cardiac output or systemic venous congestion, which are non-specific to the diagnosis of RVD. As such, RVD is easily overlooked, and the relative contribution of RV dysfunction to postoperative morbidity is likely to be underestimated.We applaud the POQI group for highlighting this important condition. There is undoubtedly a need for further study of the RV in the perioperative period in addition to solutions for perioperative risk prediction and management strategies. There is much to understand, study, and trial in this area, but importantly for our patients, we are increasingly recognising the importance of these uncertainties.

Right ventricular ejection fraction derived from intraoperative three-dimensional transesophageal echocardiography versus cardiac magnetic resonance imaging

PURPOSE

Right ventricle (RV) assessment is critical during cardiac surgery. Traditional assessment consists of visual estimation and measurement of validated parameters. Cardiac magnetic resonance imaging (cMRI) is the gold standard for RV analysis, and transthoracic three-dimensional (3D) echocardiography is validated against this. We aimed to show that intraoperative 3D transesophageal echocardiography (TEE) RV assessment is feasible and can produce results that correlate with cMRI.

METHODS

We recruited cardiac surgery patients who underwent cMRI within the preceding twelve preoperative months. An anesthetic protocol was followed pre-sternotomy and a 3D RV data set was acquired. We used TOMTEC 4D RV-Function to derive RV end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF). We compared these data with the corresponding MRI values.

RESULTS

Twenty-five patients were included. Transesophageal echocardiography EDV and ESV differed from MRI measurements with a mean bias of -53 mL (95% confidence interval [CI], -80 to 26) and -21 mL (95% CI, -34 to -9). Transesophageal echocardiography EF did not differ significantly, with a mean bias of -4% (95% CI, -8 to 1). Results were unchanged after excluding MRIs older than 180 days. Correlation coefficients for EDV, ESV, and EF were r = 0.85, 0.91, and 0.80, respectively. Interclass correlation coefficients for EDV, ESV, and EF were 0.86, 0.89, and 0.96, respectively.

CONCLUSIONS

Intraoperative TEE RV, EDV, and ESV are underestimated relative to cMRI because of analysis, anesthetic, and ventilation factors. The EF showed a low mean difference, and all values showed strong correlation with MRI. Reproducibility and feasibility were excellent and increased use in clinical practice should be considered.

Predictors of Outcome in Patients with Pulmonary Hypertension Undergoing Mitral and Tricuspid Valve Surgery

Background and Objectives: Pulmonary hypertension (PH) secondary to left-sided valvular heart disease is associated with poor cardiac surgical outcome compared with patients without PH. Our objective was to investigate the prognostic factors of surgical outcome in patients with PH undergoing mitral valve (MV) and tricuspid valve (TV) surgery, in order to risk stratify their management. Materials and Methods: This is a retrospective observational study on patients with PH who underwent MV and TV surgery from 2011 to 2019. The primary outcome was all-cause mortality. The secondary outcomes were post-op respiratory and renal complications, length of intensive care unit stay and length of hospital stay. Results: Seventy-six patients were included in this study. The all-cause mortality was 13% (n = 10), with mean survival of 92.6 months. Among the patients, 9.2% (n = 7) had post-op renal failure requiring renal replacement therapy and 6.6% (n = 5) had post-op respiratory failure requiring intubation. Univariate analysis demonstrated that pre-operative left ventricular ejection fraction (LVEF), peak systolic tissue velocity at the tricuspid annulus (S') and etiology of MV disease were associated with respiratory and renal failure. Tricuspid annular plane systolic excursion (TAPSE) was associated with respiratory failure only. S', type of operation, LVEF, urgency of surgery, and etiology of MV disease were found to be predictive of mortality. After excluding redo mitral surgery, all statistically significant findings remain unchanged, with the addition of right ventricular (RV) size being associated with respiratory failure. In the subgroup analysis of routine cases (n = 56), patients with primary mitral regurgitation who underwent mitral valve repair had better survival outcome. Conclusions: Urgency of surgery, etiology of MV disease, type of operation (replacement or repair), S' and pre-op LVEF are prognostic indicators in this small cohort of patients with PH undergoing MV and TV surgery. A larger prospective study is warranted to validate our findings.

Identifying risk factors for perioperative decline in right ventricular performance in cardiac surgery patients: a prospective observational study in a tertiary care hospital

OBJECTIVES

Impaired right ventricular (RV) function after cardiac surgery is associated with morbidity and long-term mortality. The purpose of this study was to identify factors that play a role in the development of RV dysfunction in the perioperative cardiac surgery setting.

DESIGN

We performed a prospective, observational, single centre study. Over a 2-year period, baseline and perioperative characteristics were recorded. For analysis, subjects were divided into three groups: patients with a ≥3% absolute increase in postoperative RV ejection fraction (RVEF) in comparison to baseline (RVEF+), patients with a ≥3% absolute decrease in RVEF (RVEF-) and patients with a <3% absolute change in RVEF (RVEF=).

SETTING

Tertiary care hospital in the Netherlands.

PARTICIPANTS

We included all cardiac surgery patients ≥18 years of age equipped with a pulmonary artery catheter and admitted to the ICU in 2015-2016. There were no exclusion criteria. A total number of 267 patients were included (65.5% men).

OUTCOME MEASURES

Risk factors for a perioperative decline in RV function.

RESULTS

A reduction in RVEF was observed in 40% of patients. In multivariate analysis, patients with RVEF- were compared with patients with RVEF= (first-mentioned OR) and RVEF+ (second-mentioned OR). Preoperative use of calcium channel blocker (CCB) (OR 3.06, 95% CI 1.24 to 7.54/OR 2.73, 95% CI 1.21 to 6.16 (both p=0.015)), intraoperative fluid balance (FB) (OR 1.45, 95% CI 1.02 to 2.06 (p=0.039)/OR 1.09, 95% CI 0.80 to 1.49 (p=0.575)) and baseline RVEF (OR 1.22; 95% CI 1.14 to 1.30/OR 1.27, 95% CI 1.19 to 1.35 (both p<0.001)) were identified as independent risk factors for a decline in RVEF during surgery.

CONCLUSION

Apart from the impact of the perioperative FB, preoperative use of a CCB as a risk factor for perioperative reduction in RVEF is the most prominent new finding of this study.

The Outcomes of Coronary Artery Bypass Surgery after 18 Months-Is There an Influence of the Initial Right Ventricle Diastolic Dysfunction?

BACKGROUND

This study aimed to investigate the association of preoperative right heart filling indicators with outcomes after coronary artery bypass grafting (CABG) at an 18 month follow up.

METHODS

Patients who underwent CABG at a single center were included in this study. In addition to the baseline preoperative indicators and perioperative data, initial parameters of the right ventricle (RV) systolic and diastolic function were assessed.

RESULTS

Among the 189 patients, a total of 19 (10.0%) MACE (cardiovascular death, nonfatal myocardial infarction and stroke) were recorded during an 18 month follow up. In patients with the development of MACE during the initial examination, the following changes in RV function were revealed compared with the group without MACE: a decrease in the e't index (8.2 versus 9.6 cm/s, p = 0.029), an increase in the Et/e't ratio (5.25 vs. 4.42, p = 0.049) and more frequent presence of RV pseudonormal filling (p = 0.03). In the binary logistic regression analysis, the development of MACE 18 months after CABG was associated with the nonconduction of PCI before surgery, the presence of peripheral atherosclerosis, an increase in IVST and Et/e't and a decrease in LVEF.

CONCLUSIONS

RV diastolic dysfunction in the preoperative period was associated with the development of MACE within 18 months after CABG, and the ratio Et/e't was one of the independent predictors of MACE in a multiple regression analysis. This makes it expedient to include an assessment of not only systolic but also diastolic RV function in the preoperative examination. The inclusion of an assessment of RV diastolic function in the pre-CABG evaluation of patients deserves further study.

Indicators of the Right Ventricle Systolic and Diastolic Function 18 Months after Coronary Bypass Surgery

Objective. Right ventricular (RV) dysfunction after coronary artery bypass grafting (CABG) is associated with increased mortality and morbidity. In previous studies, the parameters of RV systolic function were mainly assessed, while the dynamics of RV diastolic function after surgery was practically not studied. The aim of this study was to study the dynamics of indicators of systolic and diastolic RV function after CABG as well as to identify factors associated with their presence. Methods. The study included 160 patients who underwent CABG and 36 volunteers with no history of coronary artery disease (CAD) as a control group. Echocardiographic examination of patients was performed to assess systolic and diastolic RV dysfunction before surgery and 18 months after CABG. A level of s’t < 10 cm/sec or TAPSE < 16 mm was considered as a sign of existing RV systolic dysfunction. RV diastolic dysfunction was defined as an Et/At ratio < 0.8 or >2.1 and/or an Et/et’ ratio > 6. Results. In CAD patients 18 months after CABG, there was an increase in the frequency of the right ventricular systolic (from 7.5% to 30%, p < 0.001) and diastolic (from 41.8% to 57.5%, p < 0.001) dysfunction. An increase in TAPSE (p = 0.007), a decrease in e’t (p = 0.005), and the presence of RV systolic dysfunction before surgery (p = 0.023) was associated with a significant increase in the likelihood of detecting RV systolic dysfunction 18 months after CABG (χ2(3) = 17.4, p = 0.001). High values of At before surgery (p = 0.021) and old myocardial infarction (p = 0.023) were significantly associated with an increased likelihood of detection of RV diastolic dysfunction 18 months after CABG (χ2(2) = 10.78, p = 0.005). Conclusions. This study demonstrated that in CAD patients 18 months after CABG, there was an increase in the frequency of right ventricular systolic and diastolic dysfunction. We also established the initial clinical, echocardiographic parameters, and perioperative complications associated with the presence of these changes in the postoperative period. The clinical and prognostic significance of the presence of systolic and/or diastolic RV dysfunction in patients 18 months after CABG remains to be explored.

High Versus Normal Blood Pressure Targets in Relation to Right Ventricular Dysfunction After Cardiac Surgery: A Randomized Controlled Trial

OBJECTIVE

Management of right ventricular (RV) dysfunction is challenging. Current practice predominantly is based on data from experimental and small uncontrolled studies and includes augmentation of blood pressure. However, whether such intervention is effective in the clinical setting of cardiac surgery is unknown.

DESIGN

Randomized controlled trial.

SETTING

Single-center study in a tertiary teaching hospital.

PARTICIPANTS

The study comprised 78 patients equipped with a pulmonary artery catheter (PAC), classified according to PAC-derived RV ejection fraction (RVEF); 44 patients had an RVEF of <20%, and 34 patients had an RVEF between ≥20% and <30%.

INTERVENTIONS

Patients randomly were assigned to either a normal target group (mean arterial pressure 65 mmHg) or a high target group [mean arterial pressure 85 mmHg]). The primary end- point was the change in RVEF over a one-hour study period.

MEASUREMENTS AND MAIN RESULTS

There was no significant between-group difference in change of RVEF <20% (-1% [-3.3 to 1.8] in the normal-target group v 0.5% [-1 to 4] in the high-target group; p = 0.159). There was no significant between-group difference in change in RVEF 20%-to-30% (-1% [-3 to 0] in the normal-target group v 1% [-1 to 3] in the high-target group; p = 0.074). These results were in line with the simultaneous observation that echocardiographic variables of RV and left ventricular function also remained unaltered over time, irrespective of either baseline RVEF or treatment protocol.

CONCLUSION

In a mixed cardiac surgery population with RV dysfunction, norepinephrine-mediated high blood pressure targets did not result in an increase in PAC-derived RVEF compared with normal blood pressure targets.

Perioperative Right Ventricular Dysfunction: Analysis of Outcomes

Right ventricular dysfunction (RVD) is a well-known prognostic factor for adverse outcomes in cardiovascular medicine. The right ventricle (RV) in medically managed heart failure patients and in surgical patients perioperatively generally is overshadowed by left ventricular disease. However, with advancement of various diagnostic tools and better understanding of its functional anatomy, the role of the RV is emerging in many clinical conditions. The failure of one ventricle has significant effect on the function of the other ventricle and it is predominantly due to ventricular interdependence.¹ The etiology of RVD is multifactorial and irrespective of etiology. RVD has been associated with significant increases in morbidity and mortality in various clinical scenarios.^2,3 The primary objective of this comprehensive review is to analyze various etiology-related outcomes of RVD in the perioperative population.

The Reduction in Right Ventricular Longitudinal Contraction Parameters Is Not Accompanied by a Reduction in General Right Ventricular Performance During Aortic Valve Replacement: An Explorative Study

OBJECTIVE

The aim of the present study was to identify whether the decrease of longitudinal parameters after cardiothoracic surgery (ie, tricuspid annular systolic plane excursion [TAPSE] and systolic excursion velocity [S']) is accompanied by a reduction in global right ventricular (RV) performance.

DESIGN

Prospective, observational study.

SETTING

Single-center explorative study in a tertiary teaching hospital.

PARTICIPANTS

The study comprised 20 patients who underwent aortic valve replacement with or without coronary artery bypass grafting.

INTERVENTIONS

During cardiac surgery, simultaneous measurements of RV function were performed with a pulmonary artery catheter and transesophageal echocardiography.

MEASUREMENTS AND MAIN RESULTS

TAPSE and S' were reduced significantly directly after surgery compared with the time before surgery (TAPSE from 20.8 [16.6-23.4] mm to 9.1 [5.6-15.5] mm; p < 0.001 and S' from 8.7 [7.9-10.7] cm/s to 7.2 [5.7-8.6] cm/s; p = 0.041). However, the reduction in TAPSE and S' was not accompanied by a reduction in RV performance, as assessed with the TEE-derived myocardial performance index (MPI) and pulmonary artery catheter-derived RV ejection fraction (RVEF). Both remained statistically unaltered before and after the procedure (MPI from 0.52 [0.43-0.58] to 0.50 [0.42-0.88]; p = 0.278 and RVEF from 27% [22%-32%] to 26% [22%-28%]; p = 0.294).

CONCLUSIONS

In the direct postoperative phase, the reduction of echocardiographic parameters of longitudinal RV contractility (TAPSE and S') were not accompanied by a reduction in global RV performance, expressed as MPI and RVEF. Solely relying on a single RV parameter as a marker for global RV performance may not be adequate to assess the complex adaptation of the right ventricle to aortic valve replacement.