Right Ventricular Involvement in Coronary Artery Disease: Role of Echocardiography for Diagnosis and Prognosis

Right ventricular dysfunction in the critically ill. Echocardiographic evaluation

Right ventricular dysfunction is common in critically ill patients, and is associated with increased mortality. Its diagnosis moreover remains challenging. In this review, we aim to outline the potential mechanisms underlying abnormal biomechanics of the right ventricle and the different injury phenotypes. A comprehensive understanding of the pathophysiology and natural history of right ventricular injury can be informative for the intensivist in the diagnosis and management of this condition, and may serve to guide individualized treatment strategies. We describe the main recommended parameters for assessing right ventricular systolic and diastolic function. We also define how to evaluate cardiac output and pulmonary circulation pressures with echocardiography, with a focus on the diagnosis of acute cor pulmonale and relevant applications in critical disorders such as distress, septic shock, and right ventricular infarction.

Direct comparison of echocardiography speckle tracking and cardiac magnetic resonance feature tracking for quantification of right ventricular strain: a prospective intermodality study in functional mitral regurgitation

Background

Functional mitral regurgitation (FMR) is a known risk factor for right ventricular dysfunction (RV_DYS). RV global longitudinal strain (GLS) is an emerging index of RV function; however, the magnitude of agreement between RV GLS by echocardiography (echo) and cardiac magnetic resonance (CMR) and the relative utility of each modality for both the diagnosis of RV_DYS and prognostication of all-cause mortality and heart failure hospitalization remain unknown.

Results

32% of patients had RV_DYS (EF < 50%) on CMR, among whom there was more advanced NYHA class and lower LV and RV ejection fraction (all p < 0.05). RV GLS was impaired in patients with RV_DYS whether quantified via STE or FT-CMR, with strong correlation between modalities (r = 0.81). Both STE and FT-CMR derived GLS yielded excellent detection of RV_DYS (AUC 0.94 for both), paralleling similar performance for free wall strain by both modalities (FT-CMR AUC 0.94, STE AUC 0.92) with lower accuracy demonstrated by STE derived septal strain (STE AUC 0.78 and FT-CMR AUC 0.92). RV S’ and TAPSE showed lower diagnostic accuracy (RV S’ AUC 0.77 and TAPSE AUC 0.81). During median follow up of 51 months (IQR 42, 60 months), all-cause mortality or HF hospitalization occurred in 25% (n = 25). Both STE and FT-CMR derived RV GLS stratified risk for adverse prognosis (STE p = 0.007, FT-CMR p = 0.005) whereas conventional RV indices, TAPSE and RV S’, did not (TAPSE p = 0.30, S’ p = 0.69).

Conclusion

RV GLS is a robust marker of RV_DYS irrespective of modality which provides incremental diagnostic value and improves risk stratification for event free survival beyond conventional RV indices.

An overlooked cause for reversible severe tricuspid regurgitation and pulmonary hypertension: Hibernating right ventricle

Tricuspid regurgitation (TR) can occur due to many etiologies, including primary valve disease, left heart disease, annular dilatation in atrial fibrillation, or pulmonary hypertension (PH). Functional TR is caused by tricuspid annular dilatation in the setting of right ventricular remodeling. The right ventricle (RV) ischemia is an overlooked cause of functional TR which tends to diminish with an improvement in right heart functions. We present the case of a patient in whom functional TR significantly improved after percutaneous revascularization. We highlight that the ischemic RV can present with reversible functional TR or PH and emphasized the necessity of accurate detection of the etiology.

Transthoracic Right Heart Echocardiography for the Intensivist

BACKGROUND

The impact of critical illness on the right ventricle (RV) can be profound and RV dysfunction is associated with mortality. Intensivists are becoming more facile with bedside echocardiography, however, pedagogy has largely focused on left ventricular function. Here we review measurements of right heart function by way of echocardiographic modalities and list clinical scenarios where the RV dysfunction is a salient feature.

MAIN

RV dysfunction is heterogeneously defined across many domains and its diagnosis is not always clinically apparent. The RV is affected by conditions commonly seen in the ICU such as acute respiratory distress syndrome, pulmonary embolism, RV ischemia, and pulmonary hypertension. Basic ultrasonographic modalities such as 2D imaging, M-mode, tissue Doppler, pulsed-wave Doppler, and continuous Doppler provide clinicians with metrics to assess RV function and response to therapy.

CONCLUSION

The right ventricle is impacted by various critical illnesses with substantial mortality and mortality. Focused bedside echocardiographic exams with attention to the right heart may provide intensivists insight into RV function and provide guidance for patient management.

Speckle Tracking Echocardiography: Early Predictor of Diagnosis and Prognosis in Coronary Artery Disease

Echocardiography represents a first level technique for the evaluation of coronary artery disease (CAD) which supports clinicians in the diagnostic and prognostic workup of these syndromes. However, visual estimation of wall motion abnormalities sometimes fails in detecting less clear or transient myocardial ischemia and in providing accurate differential diagnosis. Speckle tracking echocardiography (STE) is a widely available noninvasive tool that could easily and quickly provide additive information over basic echocardiography, since it is able to identify subtle myocardial damage and to localize ischemic territories in accordance to the coronary lesions, obtaining a clear visualization with a "polar map" useful for differential diagnosis and management. Therefore, it has increasingly been applied in acute and chronic coronary syndromes using rest and stress echocardiography, showing good results in terms of prediction of CAD, clinical outcome, left ventricular remodeling, presence, and quantification of new/residual ischemia. The aim of this review is to illustrate the current available evidence on STE usefulness for the assessment and follow-up of CAD, discussing the main findings on bidimensional and tridimensional strain parameters and their potential application in clinical practice.

Point-of-Care Ultrasound (POCUS) for the Cardiothoracic Anesthesiologist

Point-of-Care Ultrasound (POCUS) is a valuable bedside diagnostic tool for a variety of expeditious clinical assessments or as guidance for a multitude of acute care procedures. Varying aspects of nearly all organ systems can be evaluated using POCUS and, with the increasing availability of affordable ultrasound systems over the past decade, many now refer to POCUS as the 21^st-century stethoscope. With the current available and growing evidence for the clinical value of POCUS, its utility across the perioperative arena adds enormous benefit to clinical decision-making. Cardiothoracic anesthesiologists routinely have used portable ultrasound systems for nearly as long as the technology has been available, making POCUS applications a natural extension of existing cardiothoracic anesthesia practice. This narrative review presents a broad discussion of the utility of POCUS for the cardiothoracic anesthesiologist in varying perioperative contexts, including the preoperative clinic, the operating room (OR), intensive care unit (ICU), and others. Furthermore, POCUS-related education, competence, and certification are addressed.

Right Ventricular Failure: Pathophysiology, Diagnosis and Treatment

The prognostic significance of the right ventricle (RV) has recently been recognised in several conditions, primarily those involving the left ventricle, the lungs and their vascular bed, or the right-sided chambers. Recent advances in imaging techniques have created new opportunities to study RV anatomy, physiology and pathophysiology, and contemporary research efforts have opened the doors to new treatment possibilities. Nevertheless, the treatment of RV failure remains challenging. Optimal management should consider the anatomical and physiological particularities of the RV and include appropriate imaging techniques to understand the underlying pathophysiological mechanisms. Treatment should include rapid optimisation of volume status, restoration of perfusion pressure and improvement of myocardial contractility and rhythm, and, in case of refractory RV failure, mechanical circulatory support.

[Echocardiographic emergency diagnostics]

Echocardiography is a non-invasive, versatile imaging modality for the diagnostics and monitoring of life-threatening cardiac diseases. This article summarizes the currently valid recommendations on emergency echocardiography of the German Cardiac Society and the European Association of Cardiovascular Imaging and provides practical guidance for their implementation in emergency medicine. Echocardiography is especially important for the diagnostics of acute coronary syndrome and its potential complications, of pulmonary embolism and endocarditis as well as the differential diagnosis of patients in shock and in emergencies. A domain of increasing importance in echocardiography is the treatment monitoring of patients supported by modern cardiac assist devices.

Detection and quantitation of right ventricular reversible perfusion defects by stress SPECT myocardial perfusion imaging: A proof-of-principle study

BACKGROUND

In patients with right dominant coronary circulation, the right ventricular (RV) myocardium and the inferior region of the left ventricular (LV) myocardium share a common source of blood flow. We hypothesized that stress/rest SPECT myocardial perfusion imaging (MPI) could detect reversible perfusion defects in the RV in some patients with LV inferior wall perfusion abnormalities.

MATERIAL AND METHODS

We identified 2 groups of patients with LV inferior wall perfusion defects (with or without defects in other regions of LV myocardium) from our database. Patients in group 1 (n = 17) had reversible perfusion defects in the RV free wall by visual analysis, while patients in group 2 (n = 17) did not. The images were processed with filtered back projection and, separately, with iterative reconstruction. The images were then re-processed using an automated quantitative software that is specifically designed to include the RV in the region of interest.

RESULTS

There were 76% men in group 1 and 94% in group 2 (P <0.05). The mean age was 65±20 in group 1 vs. 63±18 years in group 2 (P < 0.05). The stress type was exercise in 30% in group 1 and 35% in group 2, with the remaining patients studied with pharmacological stress testing (P = NS). The presence of RV reversible perfusion defects using filtered back projection was more evident in 13 patients (75%), while it was better seen with iterative reconstruction in 4 patients (25%). By automated analysis, the RV reversible perfusion defect size was 19 ± 14% of RV myocardium.

CONCLUSION

This proof-of-principle study demonstrates that reversible RV perfusion defects suggestive of ischemia can be detected by SPECT myocardial perfusion imaging in some patients with LV inferior ischemia by visual analysis and can be quantitated by automated programs. Further studies on the diagnostic and prognostic relevance of assessing RV ischemia on SPECT MPI are needed.

Right coronary artery ligation in mice: a novel method to investigate right ventricular dysfunction and biventricular interaction

Right ventricular (RV) dysfunction can lead to complications after acute inferior myocardial infarction (MI). However, it is unclear how RV failure after MI contributes to left-sided dysfunction. The aim of the present study was to investigate the consequences of right coronary artery (RCA) ligation in mice. RCA ligation was performed in C57BL/6JRj mice ( n = 38). The cardiac phenotypes were characterized using high-resolution echocardiography performed up to 4 wk post-RCA ligation. Infarct size was measured using 2,3,5-triphenyltetrazolium chloride staining 24 h post-RCA ligation, and the extent of the fibrotic area was determined 4 wk after MI. RV dysfunction was confirmed 24 h post-RCA ligation by a decrease in the tricuspid annular plane systolic excursion ( P < 0.001) and RV longitudinal strain analysis ( P < 0.001). Infarct size measured ex vivo represented 45.1 ± 9.1% of the RV free wall. RCA permanent ligation increased the RV-to-left ventricular (LV) area ratio ( P < 0.01). Septum hypertrophy ( P < 0.01) was associated with diastolic septal flattening. During the 4-wk post-RCA ligation, LV ejection fraction was preserved, yet it was associated with impaired LV diastolic parameters ( E/ E', global strain rate during early diastole). Histological staining after 4 wk confirmed the remodeling process with a thin and fibrotic RV. This study validates that RCA ligation in mice is feasible and induces RV heart failure associated with the development of LV diastolic dysfunction. Our model offers a new opportunity to study mechanisms and treatments of RV/LV dysfunction after MI. NEW & NOTEWORTHY Right ventricular (RV) dysfunction frequently causes complications after acute inferior myocardial infarction. How RV failure contributes to left-sided dysfunction is elusive because of the lack of models to study molecular mechanisms. Here, we created a new model of myocardial infarction by permanently tying the right coronary artery in mice. This model offers a new opportunity to unravel mechanisms underlying RV/left ventricular dysfunction and evaluate drug therapy.

The impact of right ventricular function assessed by 2-dimensional speckle tracking echocardiography on early mortality in patients with inferior myocardial infarction

BACKGROUND

Right ventricular (RV) involvement in inferior myocardial infarction (MI) increases in-hospital morbidity and mortality.

HYPOTHESIS

RV systolic dysfunction assessed by 2-dimensional speckle tracking echocardiography (STE) might be a predictor of early mortality in patients with acute inferior MI.

METHODS

Eighty-one consecutive patients with acute inferior MI (mean age, 60.8 ± 12.7 years; 18 females) were included. RV myocardial involvement was defined as an elevation >1 mm in V₁ or V₄ R within 12 hours of symptom onset. RV function was assessed by STE. Patients were followed for 30 days for all-cause mortality.

RESULTS

Thirty-eight patients had RV myocardial involvement, and they had significantly lower tricuspid annular plane systolic excursion (TAPSE), tricuspid annular systolic velocity (RVS), and left ventricular (LV) and RV global longitudinal strain (GLS). Nine patients (11%) died within 30 days. The mean age of mortality group was higher with more female frequency. They had significantly higher pro-BNP, hs-troponin T, and creatinine levels, but lower hemoglobin levels. TIMI 3 flow was significantly less achieved in mortality group. RV myocardial involvement was more frequent in the mortality group, and they had significantly lower TAPSE, RVS, and LV and RV GLS. Multivariate analysis revealed that age and RV GLS were independent predictors of early mortality. RV GLS ≤ -14% predicted early mortality in patients with acute inferior MI with a sensitivity of 88.9% and a specificity of 62.5% (AUC: 0.817, P = 0.002).

CONCLUSIONS

RV GLS may be useful in predicting early mortality in patients with acute inferior MI.

Stressing the Cardiopulmonary Vascular System: The Role of Echocardiography

The cardiopulmonary vascular system represents a key determinant of prognosis in several cardiorespiratory diseases. Although right heart catheterization is considered the gold standard for assessing pulmonary hemodynamics, a comprehensive noninvasive evaluation including left and right ventricular reserve and function and cardiopulmonary interactions remains highly attractive. Stress echocardiography is crucial in the evaluation of many cardiac conditions, typically coronary artery disease but also heart failure and valvular heart disease. In stress echocardiographic applications beyond coronary artery disease, the assessment of the cardiopulmonary vascular system is a cornerstone. The possibility of coupling the left and right ventricles with the pulmonary circuit during stress can provide significant insight into cardiopulmonary physiology in healthy and diseased subjects, can support the diagnosis of the etiology of pulmonary hypertension and other conditions, and can offer valuable prognostic information. In this state-of-the-art document, the topic of stress echocardiography applied to the cardiopulmonary vascular system is thoroughly addressed, from pathophysiology to different stress modalities and echocardiographic parameters, from clinical applications to limitations and future directions.

Impact of right ventricular diastolic dysfunction on clinical outcomes in inferior STEMI

BACKGROUND

The aim of this study was to investigate the prognostic value of restrictive right ventricular filling pattern (RRVFP) in patients with the first acute inferior wall myocardial infarction (IWMI) complicated by right ventricular myocardial infarction (RVMI) undergoing primary percutaneous coronary intervention (p-PCI).

METHOD

A total of 152 patients with acute IWMI complicated by RVMI undergoing p‑PCI were divided into two groups according to the presence of RRVFP. RRVFP was defined as tricuspid diastolic early/late flow velocities (Et/At) > 2 and Et deceleration time (DT) < 120 ms.

RESULTS

There were 23 patients with RRVFP in the study cohort. At, DTt, isovolumetric relaxation time (IVRT), and tissue Doppler tricuspid annular late velocity (A't) were reduced significantly in patients with RRVFP than in those without RRVFP (At 19.6 ± 2.7 vs. 39.1 ± 7.4 cm/s, p < 0.001; DTt 106 ± 13 vs.156 ± 21 ms, p = 0.001; IVRT 59 ± 6.7 vs. 62 ± 7.4 ms, p = 0.01; A't 4.6 ± 1.1 vs. 8.6 ± 1.05, p = 0.001). Et/At ratios were higher in patients with RRVFP than in those without RRVFP (Et/At 2.20 ± 0.2 vs. 1.15 ± 0.37, p < 0.001). Et, tissue Doppler tricuspid annular early velocity (E't), E't/A't ratio, and Et/E't ratio were not significantly different between groups (Et 43.3 ± 5.4 vs. 40.7 ± 9.2 cm/s p = 0.18; E't 8.8 ± 1.4 vs. 9.5 ± 2.3, p = 0.15; E't/A't 1.08 ± 0.24 vs. 1.13 ± 0.30, p = 0.52; Et/E't ratio 5.0 ± 1.1 vs. 4.5 ± 1.5 p = 0.09). Presence of E't/A't > 2, short DTt, RRVFP, unsuccessful p‑PCI, and cardiogenic shock on admission were independent predictors of in-hospital mortality (p < 0.05) in multivariable logistic regression analysis.

CONCLUSION

Presence of RRVFP is associated with in-hospital mortality in patients presenting with their first IWMI complicated by RVMI.

Echocardiographic assessment of the right ventricle in the current era: Application in clinical practice

The right ventricle has unique structural and functional characteristics. It is now well recognized that the so-called forgotten ventricle is a key player in cardiovascular physiology. Furthermore, there is accumulating evidence that demonstrates right ventricular dysfunction as an important marker of morbidity and mortality in several commonly encountered clinical situations such as heart failure, pulmonary hypertension, pulmonary embolism, right ventricular myocardial infarction, and adult congenital heart disease. In contrast to the left ventricle, echocardiographic assessment of right ventricular function is more challenging as volume estimations are not possible without the use of three-dimensional (3D) echocardiography. Guidelines on chamber quantification provide a standardized approach to assessment of the right ventricle. The technique and limitations of each of the parameters for RV size and function need to be fully understood. In this era of multimodality imaging, echocardiography continues to remain a useful tool for the initial assessment and follow-up of patients with right heart pathology. Several novel approaches such as 3D and strain imaging of the right ventricle have expanded the usefulness of this indispensable modality.

Role of Two-Dimensional Speckle-Tracking Echocardiography Strain in the Assessment of Right Ventricular Systolic Function and Comparison with Conventional Parameters

Despite the already well-known role the right side of the heart plays in many diseases, right ventricular (RV) function has only recently been carefully considered. Echocardiography is the first-line diagnostic technique for the assessment of the right ventricle and right atrium, whereas cardiac magnetic resonance is considered the gold standard but is limited by cost and availability. According to the current guidelines, systolic RV function should be assessed by several conventional measurements, but the efficacy of these parameters as diagnostic and prognostic tools has been questioned by many authors. The development in recent years of myocardial deformation imaging techniques and their application to the right heart chambers has allowed deeper evaluation of the importance of RV function in the pathophysiology of a large number of cardiovascular conditions, but the real value of this new tool has not been completely clarified. The aim of this review is to provide a wide and careful analysis of findings available in the literature about the assessment of RV systolic function by strain measurements, comparing them with conventional parameters and evaluating their role in several clinical settings.

Right and left heart dysfunction predict mortality in pulmonary hypertension

In pulmonary hypertension (PH), the right heart dysfunction is a strong predictor of adverse clinical outcome, while the role of the left heart is not fully determined. The aim of this study was to identify predictors of mortality in precapillary PH including measures of both right and left heart function. We studied 34 patients (mean age 64 ± 13, range 31-82 years, 24 females) with precapillary PH, all of whom underwent detailed Doppler echocardiographic examination of the right and left heart function using conventional and speckle-tracking echocardiography. Patients were followed up for up to 8 years (mean 4·2 ± 1·9 years). At follow-up, 16 patients survived. Left ventricular (LV) filling time (P = 0·007), pulmonary artery acceleration time (P = 0·009), right atrial pressure (RAP) (P<0·001) and tricuspid regurgitation (TR) severity (P = 0·007) were worse in the deceased group. RV global longitudinal strain (GLS) (P = 0·001), RAP (P≤0·001), LV filling time (P<0·001) and TR severity (P<0·001) were the most accurate predictors, having the largest AUC (>0·65) and carried the highest risk for mortality (P<0·001 for all). The strongest predictors of mortality in precapillary PH indirectly reflect both left and right heart dysfunction including atrial structure and function disturbances. While an interaction pattern is observed, it needs to be confirmed in a larger cohort.