Pulmonary Embolism and Right Heart Function: Insights from Myocardial Doppler Tissue Imaging

Evaluation of Right Ventricular Function and Dyssynchrony in a Dog Model of Acute Pulmonary Embolism: Diagnostic Utility and Reversibility

Background

The diagnosis of acute pulmonary thromboembolism is challenging in dogs. Little has been reported on changes in echocardiographic indices in dogs with acute pulmonary thromboembolism. The objective of this study was to validate the relationship between echocardiographic indices and right heart catheterization variables in dogs with acute pulmonary embolism and to identify a useful echocardiographic index for diagnosing acute pulmonary embolism.

Materials and Methods

Six healthy laboratory beagles were included in the study. Echocardiography and right heart catheterization were performed in a dog model of acute pulmonary embolism produced by microsphere injection. Echocardiographic indices, including the right ventricular (RV) Tei index, RV longitudinal strain, and the dyssynchrony index using speckle tracking echocardiography, transmitral flow, and eccentricity index, were measured.

Results

The mean pulmonary arterial pressure increased (22.2 ± 1.2 mmHg) and the blood pressure decreased after microsphere injection. Although the mean pulmonary arterial pressure remained elevated, the blood pressure recovered 2 days after the microsphere injection. Most echocardiographic indices of RV function were significantly impaired following microsphere injection and recovered after 2 days. In contrast, the RV Tei index was significantly impaired after microsphere injection and the impairment persisted after 2 days. Multivariable analysis revealed that the RV Tei index was an independent echocardiographic predictor of pulmonary vascular resistance (β = 0.88, P < 0.001), and transmitral early diastolic wave was an independent predictor of the cardiac index (β = −0.86, P = 0.001).

Conclusions

The RV Tei index is a useful echocardiographic index for diagnosing acute pulmonary embolism. Ventricular interdependence may be an important factor causing low cardiac output in dogs with acute pulmonary embolism.

Systolic pulmonary regurgitation affects the outcome of patients with severe systolic heart failure

AIMS

Little is known of the impact of systolic pulmonary regurgitation (PR) on acute decompensated heart failure (HF). We assessed the prevalence and prognostic significance of systolic PR in patients with severe HF.

METHODS AND RESULTS

According to recent 10 year echocardiographic database of E-Da Hospital, 533 patients admitted for first systolic heart failure (HF) and left ventricular ejection fraction <35% were under investigation. Systolic PR was defined as the presence of pulmonary backward flow persistent after QRS in electrocardiogram. Isovolumic contraction/relaxation time and myocardial performance index were derived by tissue Doppler imaging. Right ventricular (RV) function was assessed by RV fractional area change. Estimated pulmonary vascular resistance (PVR) was assessed by the ratio of peak tricuspid regurgitation velocity to the RV outflow tract time-velocity integral. The factors associated with systolic PR were assessed by multivariate logistic regression. Cox proportional regression analyses were used to estimate the impact of cardiovascular events including HF rehospitalization and cardiovascular death. For estimated prevalence of 5480 control subjects, echocardiographic screens in those with normal left ventricular ejection fraction were performed. Of 533 systolic HF cases, 143 (26.8%) had systolic PR during indexed hospitalization. Among 143 cases, 86% systolic PR disappeared during late follow-up. In control subjects, 0.3% (18/5480) had systolic PR. Systolic PR correlated to RV dysfunction, estimated PVR, E/e', sign of low cardiac output, and pulmonary oedema. Systolic PR was associated independently with further cardiovascular events (hazard ratio 2.266, 95% confidence interval 1.682-3.089, P < 0.0001) including cardiovascular death and HF rehospitalization.

CONCLUSIONS

Systolic PR is not uncommon in systolic HF and is associated with high PVR and RV dysfunction. Systolic PR significantly impacts cardiovascular outcome.

Cor pulmonale: the role of traditional and advanced echocardiography in the acute and chronic settings

Cor pulmonale is the condition in which the right ventricle undergoes morphological and/or functional changes due to diseases that affect the lungs, the pulmonary circulation, or the breathing process. Depending on the speed of onset of the pathological condition and subsequent effects on the right ventricle, it is possible to distinguish the acute cor pulmonale from the chronic type of disease. Echocardiography plays a central role in the diagnostic and therapeutic work-up of these patients, because of its non-invasive nature and wide accessibility, providing its greatest usefulness in the acute setting. It also represents a valuable tool for tracking right ventricular function in patients with cor pulmonale, assessing its stability, deterioration, or improvement during follow-up. In fact, not only it provides parameters with prognostic value, but also it can be used to assess the efficacy of treatment. This review attempts to provide the current standards of an echocardiographic evaluation in both acute and chronic cor pulmonale, focusing also on the findings present in the most common pathologies causing this condition.

Incremental Value of ePLAR—The Echocardiographic Pulmonary to Left Atrial Ratio in the Assessment of Sub-Massive Pulmonary Emboli

Background: Acute pulmonary embolism (PE) is characterized hemodynamically by abrupt obstruction in trans-pulmonary blood flow. The echocardiographic Pulmonary to Left Atrial ratio (ePLAR, tricuspid regurgitation Vmax/mitral E/e’) has been validated as a non-invasive surrogate for trans-pulmonary gradient (TPG) that accurately differentiates pre-capillary from post-capillary chronic pulmonary hypertension. This study assessed ePLAR as an incremental echocardiographic assessment tool compared with traditional measures of right ventricular pressure and function. Methods: In total, 110 (57.4 ± 17.6 years) patients with confirmed sub-massive pulmonary emboli with contemporaneous echocardiograms (0.3 ± 0.9 days) were compared with 110 age-matched controls (AMC). Results: Tricuspid velocities were higher than AMC (2.6 ± 0.6 m/s vs. 2.4 ± 0.3 m/s, p < 0.05), although still consistent with “normal” right ventricular systolic pressures (34.2 ± 13.5 mmHg vs. 25 ± 5.3 mmHg, p < 0.05) with lower mitral E/e’ values (8.2 ± 3.8 vs. 10.8 ± 5.1, p < 0.05). ePLAR values were higher than AMC (0.36 ± 0.14 m/s vs. 0.26 ± 0.10, p < 0.05) suggesting significantly elevated TPG. Detection of abnormal echocardiographic findings increased from 29% (TRVmax ≥ 2.9 m/s) and 32% (reduced tricuspid annular plane systolic excursion) to 70% with ePLAR ≥ 0.3 m/s. Conclusions: Raised ePLAR values in acute sub-massive pulmonary embolism suggest elevated trans-pulmonary gradients even in the absence of acutely increased pulmonary artery pressures. ePLAR dramatically increases the sensitivity of echocardiography for detection of hemodynamic perturbations in sub-massive pulmonary embolism patients, which may offer clinical utility in diagnosis and management.

Change in right ventricular function in an American cocker spaniel with acute pulmonary thromboembolism

A 12-year-old neutered female American cocker spaniel weighing 9.9 kg was presented for evaluation with a 2-day history of dyspnea and anorexia. Echocardiography revealed severe pulmonary hypertension (estimated systolic pulmonary arterial pressure, 93.4 mmHg) with right heart enlargement, pulmonary arterial dilation, and right ventricular dysfunction. The dilation of left heart and congenital cardiac shunt were not observed. Pulmonary thromboembolism (PTE) was confirmed by computed tomographic angiography. After treatment with antiplatelet and anticoagulant, the clinical sign and the echocardiographic abnormality of right heart were improved. These echocardiographic findings are not specific for PTE, but it can be useful as a rule-in test for PTE when other causes of pulmonary hypertension are excluded and a monitor of therapeutic efficacy.

Cardiopulmonary Exercise Testing in Patients Following Massive and Submassive Pulmonary Embolism

Background

Little data exist regarding the functional capacity of patients following acute pulmonary embolism. We sought to characterize the natural history of symptom burden, right ventricular (RV) structure and function, and exercise capacity among survivors of massive and submassive pulmonary embolism.

Methods and Results

Survivors of submassive or massive pulmonary embolism (n=20, age 57±13.3 years, 8/20 female) underwent clinical evaluation, transthoracic echocardiography, and cardiopulmonary exercise testing at 1 and 6 months following hospital discharge. At 1 month, 9/20 (45%) patients had New York Heart Association II or greater symptoms, 13/20 (65%) demonstrated either persistent RV dilation or systolic dysfunction, and 14/20 (70%) had objective exercise impairment as defined by a peak oxygen consumption (V˙O₂) of <80% of age‐sex predicted maximal values (16.25 [13.4–20.98] mL/kg per minute). At 6 months, no appreciable improvements in symptom severity, RV structure or function, and peak V˙O₂ (17.45 [14.08–22.48] mL/kg per minute, P=NS) were observed. No patients demonstrated an exercise limitation attributable to either RV/pulmonary vascular coupling, as defined by a VE/VCO₂ slope >33, or a pulmonary mechanical limit to exercise at either time point. Similarly, persistent RV dilation or dysfunction was not significantly related to symptom burden or peak V˙O₂ at either time point.

Conclusions

Persistent symptoms, abnormalities of RV structure and function, and objective exercise limitation are common among survivors of massive and submassive pulmonary embolism. Functional impairment appears to be attributable to general deconditioning rather than intrinsic cardiopulmonary limitation, suggesting an important role for prescribed exercise rehabilitation as a means toward improved patient outcomes and quality of life.

Dramatic Normalization of the Echocardiographic Pulmonary-to-Left Atrial Ratio with Thrombolysis in a Case of Life-Threatening Submassive Pulmonary Emboli

•A 74 year old male presented with bilateral submassive pulmonary emboli with moderately severe pulmonary hypertension with right ventricular systolic pressure (RVSP) 63 mm Hg. •Echocardiographic pulmonary-to-left atrial ratio (ePLAR) markedly elevated at 0.78 m/s (normal range for age 0.30 ± 0.09 m/s) suggesting significantly elevated transpulmonary gradient. •Thrombolysis almost fully resolved symptomatic embolic burden and normalized right ventricular function. RVSP 37 mm Hg, ePLAR 0.32 m/s. •One month after lysis, RVSP 26 mm Hg, ePLAR 0.22 m/s, now within the normal range for age.

Clinical Utility of Echocardiography for the Diagnosis and Prognosis in Children with Bronchopulmonary Dsyplasia

Background

Bronchopulmonary dysplasia (BPD) may result in chronic pulmonary artery hypertension and right ventricular (RV) dysfunction. Various echocardiographic assessments of RV dysfunction have been used to determine whether echocardiographic measurements of premature infants with BPD could provide sensitive measures of RV function that correlates with BPD severity.

Methods

Twenty-eight control subjects without BPD (non BPD group), 28 patients with mild BPD, 11 patients with moderate BPD, and six patients with severe BPD underwent echocardiograms with standard measurement such as ejection fraction by M-mode, tricuspid regurgitation pressure gradient, myocardial performance index (MPI) derived from pulse Doppler, and tissue Doppler imaging (TDI) measurements. BPD severity was classified by the NICHD/NHLBI/ORD workshop rating scale. Twenty-eight control subjects without BPD (non BPD group), 28 patients with mild BPD, 11 patients with moderate BPD, and six patients with severe BPD underwent echocardiograms with standard measurement such as ejection fraction by M-mode, tricuspid regurgitation pressure gradient, myocardial performance index (MPI) derived from pulse Doppler, and TDI measurements. BPD severity was classified by the NICHD/NHLBI/ORD workshop rating scale.

Results

None of the standard echocardiographic findings was significantly different between the control group and BPD groups. However, mean septal TDI-MPI of the severe BPD group (0.68 ± 0.06) was significantly (p < 0.01) higher than that of the non-BPD (0.58 ± 0.10) or the mild BPD group (0.59 ± 0.12). In addition, mean RV TDI-MPI of the severe BPD group (0.71 ± 0.13) was significantly (p < 0.05) higher than that of the non-BPD group (0.56 ± 0.08) or the mild BPD group (0.60 ± 0.125). Linear regression showed a good correlation between the severity of BPD and RV TDI-MPI (p = 0.01, R = 0.30) or septal TDI-MPI (p = 0.04, R = 0.24).

Conclusion

Echocardiographic evaluation of RV function based on an assessment of RV TDI-MPI can provide RV dysfunction parameter in premature infants with BPD.

The significance of mitral and tricuspid valve systolic lateral annular velocities in the diagnosis of acute pulmonary embolism in patients with chronic heart failure

INTRODUCTION

The diagnosis of acute pulmonary embolism (APE) in patients with chronic heart failure (CHF) remains a difficult task, despite the refinement of imaging techniques. The goal of this study was to assess the value of measuring tricuspid and mitral valve systolic annular velocities in CHF patients with suspected PE by tissue Doppler imaging (TDI).

MATERIAL AND METHODS

The study included 75 patients with previously diagnosed CHF, admitted due to resting dyspnea, with a maximum tricuspid regurgitation pressure gradient (TRPG) of ≥ 35 mm Hg and positive D-dimer assay. Spiral computed tomography (sCT) was performed on all subjects to confirm APE. Acute pulmonary embolism was diagnosed in 35 patients (PE+), and excluded in 40 others (PE-). Tissue Doppler imaging was performed to measure maximum systolic lateral annular velocities in the mitral (SmLV) and tricuspid (SmRV) valves, as well as the SmRV/SmLV ratio.

RESULTS

PE+ subjects were found to have higher SmLV than PE- subjects (6.0 cm/s (2.0-13.8 cm/s) vs. 4.2 cm/s (1.3-9.1 cm/s), p = 0.003). SmRV/SmLV ratios were 1.05 (0.50-2.50) and 1.56 (0.62-4.30), respectively (p < 0.0001). Areas under ROC curves for diagnosis of APE were 0.700 for SmLV and 0.789 for SmRV/SmLV. In multivariate logistic regression analysis, only SmRV/SmLV was statistically significant, with an odds ratio for APE of 6.26 (95% CI: 1.53-25.59; p = 0.009).

CONCLUSIONS

Tissue Doppler imaging of the lateral tricuspid and mitral annuli is a useful clinical tool that can help identify PE in CHF patients. Those patients who fulfill these criteria should be considered for further diagnostic studies to confirm PE.

Usefulness of right ventricular tissue Doppler imaging for diagnosis of right ventricular myocardial infarction

BACKGROUND

Right ventricular myocardial infarction (RVMI) is a complication of acute inferior myocardial infarction and sometimes causes severe hemodynamic disturbance. It is therefore important to promptly detect RVMI and assess the severity of right ventricular (RV) dysfunction. Tissue Doppler imaging (TDI) is a useful method to assess left ventricular function and RV function. In this study, we investigated the possibility of diagnosing RVMI using tricuspid annular velocity determined by TDI.

METHODS

Thirty consecutive patients with first acute inferior myocardial infarction were studied. The diagnosis of RVMI was based on an ST-segment elevation of at least 0.1 mV in lead V4R. The patients were classified into 12 patients with RVMI (the RVMI group) and 18 patients without RVMI (non-RVMI group). All patients underwent two-dimensional echocardiography, pulsed Doppler and TDI, and coronary angiography within 48 h after onset of myocardial infarction. Tricuspid inflow velocity was recorded by pulsed Doppler and early diastolic tricuspid inflow velocity (TVE) was measured. Peak early diastolic velocity of the tricuspid annulus (TVe') at the RV free wall was recorded using TDI. The ratio of TVE to TVe' (TVE/TVe') was calculated.

RESULTS

TVe' was significantly lower in the RVMI group compared to that in the non-RVMI group (5.9 ± 1.3 vs. 9.1 ± 3.1; p = 0.0025). On the basis of a TVe' cutoff value of less than 8.3 cm/s, RVMI was diagnosed with 100 % sensitivity and 61 % specificity.

CONCLUSIONS

The early diastolic tricuspid annular velocity determined by TDI is a noninvasive and sensitive index for diagnosing RVMI.

Cardiac findings and long-term thromboembolic outcomes following pulmonary embolism in children: a combined retrospective-prospective inception cohort study

In paediatric pulmonary embolism, cardiac findings and thromboembolic outcomes are poorly defined. We conducted a mixed retrospective-prospective cohort study of paediatric pulmonary embolism at the Children's Hospital Colorado between March, 2006 and January, 2011. A total of 58 consecutive children - age less than or equal to 21 years - with acute pulmonary embolism were enrolled. Data collection included clinical and laboratory characteristics, treatments, serial echocardiographic and electrocardiographic findings, and outcomes of pulmonary embolism non-resolution and recurrence. The median age was 16.5 years ranging from 0 to 21 years. The most prevalent clinical risk factors were oral contraceptive pill use (52% of female patients), presence of a non-infectious inflammatory condition (21%), and trauma (21%). Thrombophilias included heterozygous factor V Leiden in 21%; antiphospholipid antibody syndrome was established in 31% overall. Proximal pulmonary artery involvement was present in 34%. At presentation, nearly half of the patients had hypoxaemia and 37% had tachycardia. The classic electrocardiographic finding of S1Q3T3 was present in 12% acutely; tricuspid regurgitation greater than 3 metres per second, septal flattening, and right ventricular dilation were each present on acute echocardiogram in 25%. Nearly all patients received therapeutic anticoagulation, with initial systemic tissue plasminogen activator administered in 16% for occlusive iliofemoral deep venous thrombosis and/or massive pulmonary embolism. Pulmonary embolism resolution was observed in 82% by 6 months. Recurrent pulmonary embolism occurred in 9%. There were no pulmonary embolism-related deaths. Right ventricular dysfunction was rare in follow-up. These data indicate that acute heart strain is common, but chronic cardiac dysfunction is rare, following aggressive management of acute pulmonary embolism in children.

d-Dimer and simplified pulmonary embolism severity index in relation to right ventricular function

BACKGROUND

Right ventricular (RV) involvement in pulmonary embolism (PE) is an ominous sign. The aim of this study was to investigate the extent to which the d-dimer level or simplified PE severity index (sPESI) indicates RV dysfunction in patients with preserved systemic arterial pressure.

METHODS

Right ventricular function was studied in 34 consecutive patients with acute nonmassive PE by echocardiography including Doppler tissue imaging within 24 hours after arrival to the hospital. d-Dimer and sPESI were assessed upon arrival.

RESULTS

d-Dimer correlated with RV pressure (Rs, 0.60; P < .001) and pulmonary vascular resistance (PVR; Rs, 0.68; P < .0001) and tended to be related to myocardial performance index (MPI; Rs, 0.31; P = .067). Compared to a level less than 3.0 mg/L, patients with d-dimer 3.0 mg/L or higher had lower systolic tricuspid annular velocity (11.3 ± 2.7 vs 13.5 ± 2.7 cm/s; P < .05), a prolonged MPI (0.8 ± 0.3 vs 0.5 ± 0.2; P < .01), increased RV pressure (58 ± 13 vs 37 ± 12 mm Hg; P < .001), and increased PVR (3.3 ± 1.1 vs 1.8 ± 0.4 Woods units; P < .001). Patients in the high-risk sPESI group had higher filling pressure than those in the low risk sPESI group.

CONCLUSIONS

In the acute stage of PE, a d-dimer level 3 mg/L or higher may identify nonmassive PE patients with RV dysfunction and thereby help to determine their risk profile. We found no additional value for sPESI in this context.

[Role of echocardiography in the hemodynamic monitorization of critical patients]

The use of echocardiography in intensive care units in shock patients allows us to measure various hemodynamic variables in an accurate and a non-invasive manner. By using echocardiography not only as a diagnostic technique but also as a tool for continuous hemodynamic monitorization, the intensivist can evaluate various aspects of shock states, such as cardiac output and fluid responsiveness, myocardial contractility, intracavitary pressures, heart-lung interaction and biventricular interdependence. However, to date there has been little guidance orienting echocardiographic hemodynamic parameters in the intensive care unit, and intensivists are usually not familiar with this tool. In this review, we describe some of the most important hemodynamic parameters that can be obtained at the patient bedside with transthoracic echocardiography in critically ill patients.

Diagnosis and assessment of pulmonary vascular disease by Doppler echocardiography

Pulmonary hypertension (PH) is a relatively misunderstood disease, partly related to the fact that many perceive PH to be a singular diagnosis. An unintended consequence of this is the misapplication of the role of the Doppler-Echocardiographic (DE) examination, as well as an underappreciation for its ability to help discern PH pathophysiology prior to right heart catheterization. Since DE often serves as the "gatekeeper" to invasive right heart catheterization, misinterpretation of the DE can lead to missed or delayed diagnosis with devastating consequences. Too often, the primary or nearly exclusive focus of the DE examination is placed on the pulmonary artery pressure estimation. Two main issues with this approach are that Doppler pressure estimations can be inaccurate and even when accurate, without integration of additional 2-D and Doppler information, the clinician will often still not appreciate the pathophysiology of the PH nor its clinical significance. This review will focus on the 2-D and Doppler features necessary to assess pulmonary vascular disease (PVD), discern the salient differences between PVD and pulmonary venous hypertension (PVH), and how to integrate these key DE parameters such that PH pathophysiology can be determined noninvasively and early in the patient workup. Overreliance on any single DE metric, and especially PA pressure estimation, detracts from the overall diagnostic potential of the DE examination. Integrating the relative balance of right and left heart findings, along with proper Doppler interpretation provides a wealth of clinical and pathophysiologic insight prior to invasive hemodynamic assessment. The end results are heightened awareness and improved identification of which patients should be referred for further invasive testing, as well the use of the DE information to compliment the findings from invasive testing.

Right ventricular heart failure from pulmonary embolism: key distinctions from chronic pulmonary hypertension

BACKGROUND

The right ventricle normally operates as a low pressure, high-flow pump connected to a high-capacitance pulmonary vascular circuit. Morbidity and mortality in humans with pulmonary hypertension (PH) from any cause is increased in the presence of right ventricular (RV) dysfunction, but the differences in pathology of RV dysfunction in chronic versus acute occlusive PH are not widely recognized.

METHODS AND RESULTS

Chronic PH that develops over weeks to months leads to RV concentric hypertrophy without inflammation that may progress slowly to RV failure. In contrast, pulmonary embolism (PE) results in an abrupt vascular occlusion leading to increased pulmonary artery pressure within minutes to hours that causes immediate deformation of the RV. RV injury is secondary to mechanical stretch, shear force, and ischemia that together provoke a cytokine and chemokine-mediated inflammatory phenotype that amplifies injury.

CONCLUSIONS

This review will briefly describe causes of pulmonary embolism and chronic PH, models of experimental study, and pulmonary vascular changes, and will focus on mechanisms of right ventricular dysfunction, contrasting mechanisms of RV adaptation and injury in these 2 settings.

Assessment of the right ventricle by echocardiography: a primer for cardiac sonographers

The assessment of right ventricular (RV) structure and function by echocardiography has been improved by advancements that include Doppler tissue imaging, strain imaging, and three-dimensional imaging. Doppler tissue imaging and strain imaging can be useful for the assessment of regional RV systolic and diastolic function. Three-dimensional imaging has been reported to determine RV volumes and ejection fraction, which have previously been cumbersome to measure with conventional two-dimensional echocardiography. This article addresses the role of conventional and newer methods of echocardiography to assist sonographers in understanding the technical considerations, limitations, and pitfalls of image acquisition and analysis of RV structure and function.

Differential strain and velocity generation along the right ventricular free wall in pulmonary hypertension

BACKGROUND

In contrast to the homogeneously distributed deformation properties within the left ventricle, the right ventricular (RV) free wall (RVFW) shows a more inhomogeneous distribution. It has been demonstrated that pulmonary hypertension (PH) results in significant RVFW mechanical delay.

OBJECTIVE

To assess the effect of the degree of pulmonary arterial systolic pressure on the RVFW strain gradient and on myocardial velocity generation.

METHODS

Peak longitudinal strain and velocity data were collected from three different segments (basal, mid- and apical) of the RVFW in 17 normal individuals and 31 PH patients.

RESULTS

A total of 144 RV wall segments were analyzed. RVFW strain values in individuals without PH were higher in the mid and apical segments than in the basal segment. In contrast, RVFW strain in PH patients was higher in basal segments and diminished toward the apex. In terms of RVFW velocities, both groups showed decremental values from basal to apical segments. Basal and mid-RVFW velocities were significantly lower in PH patients than in individuals without PH.

CONCLUSIONS

PH results in significant alterations of strain and velocity generation that occurs along the RVFW. Of these abnormalities, the reduction in strain from the mid and apical RVFW segments was most predictive of PH. It is important to be aware of these differences in strain generation when studying the effect of PH on the right ventricle. Additional studies are required to determine whether these differences are due to RV remodelling.

Myocardial tissue Doppler changes in patients with bronchopulmonary dysplasia

OBJECTIVE

To determine whether tissue Doppler measurements provide sensitive measures of right ventricular function that correlate with the severity of bronchopulmonary dysplasia (BPD).

STUDY DESIGN

21 subjects (6 control subjects with no/mild BPD, 7 patients with moderate BPD, and 8 patients with severe BPD) underwent limited echocardiograms with standard M-mode, mitral and tricuspid inflow velocities, and tissue Doppler features measured. BPD severity was scored by using the NICHD/NHLBI/ORD workshop rating scale by physicians blinded to the echocardiogram results. Groups were compared by using 1-way analysis of variance with post-hoc testing and linear regression.

RESULTS

Patients with moderate BPD had a higher early Doppler inflow velocity to the early tissue Doppler velocity ratio (E/E' ratio; P = .03), corresponding to increased end diastolic pressure, compared with patients with no/mild BPD. Patients with severe BPD had a higher E/E' ratio (P = .004) than patients with no/mild BPD. Linear regression demonstrated a correlation between BPD category and right ventricle E/E' (P = .007, R(2) = 0.33) and left ventricular myocardial performance index (P = .02, R(2) = 0.28).

CONCLUSION

Increasing right ventricle E/E' ratio correlates with clinical severity of BPD. Abnormal left ventricular myocardial performance index was noted to correlate with the grade of BPD. Further longitudinal studies of tissue Doppler echocardiographic assessment of cardiac function in premature infants with BPD are needed.

Midventricular peak systolic strain and Tei index of the right ventricle correlated with decreased right ventricular systolic function in patients with acute pulmonary thromboembolism

BACKGROUND

Assessment of right ventricular (RV) systolic function remains difficult because of the RV's complex shape. We aimed to evaluate RV systolic function with strain analysis in patients with acute pulmonary thromboembolism (PTE).

PATIENTS AND METHODS

From March 2005 to June 2006, 28 consecutive patients with acute PTE were included in this study. After excluding four patients, three with recurrent episodes of PTE and one with permanent pacemaker, the remaining 24 patients (10 males, mean age 69.0+/-10 years) were analyzed.

RESULTS

Mean RV fractional area change (RVFAC) was 20.1+/-8.7%; RV Tei index was 0.86+/-0.23; tricuspid annular plane systolic excursion (TAPSE) was 1.56+/-0.31 cm; and TR Vmax was 3.6+/-0.4 m/s at the time of diagnosis. Midventricular peak systolic strain of RV was markedly decreased (base: -18.0+/-6.6%, midventricle: -5.4+/-12.8%, apex: -10.6+/-8.1%). After treatment, follow-up echocardiographic data were obtained from 20 patients (mean: 11.0+/-8.2 days, duration: 4-34 days). Mean RVFAC, RV Tei index, TAPSE and TR Vmax were significantly improved (P<0.001). Midventricular peak systolic strains of RV were also significantly improved (base: -20.9+/-7.0%, P=0.055, midventricle: -21.1+/-6.8%, P<0.001, apex: -12.7+/-8.1%, P=0.314). Midventricular peak systolic strain of RV showed significant negative correlation with RVFAC (r=-0.660, P<0.001) and TAPSE (r=-0.642, P<0.001). Also, the RV Tei index showed significant correlation with RVFAC (r=-0.646, P<0.001) and TAPSE (r=-0.647, P<0.001).

CONCLUSIONS

Midventricular peak systolic strain and RV Tei index decreased in the patients with acute PTE and improved after stabilization. These values can therefore be used to assess RV systolic function in patients with acute PTE.

Tricuspid Annular Systolic Velocity Predicts Maximal Oxygen Consumption During Exercise in Adult Patients with Repaired Tetralogy of Fallot

BACKGROUND

Many patients with repaired tetralogy of Fallot (TOF) have clinically important pulmonary regurgitation that can eventually lead to right ventricular (RV) dilatation and dysfunction and associated morbidity and mortality. Unfortunately, standard echocardiographic techniques to evaluate RV size and function can be inaccurate. Newer Doppler modalities such as Doppler tissue imaging (DTI) can detect subtle changes in myocardial velocities and may better identify subclinical RV dysfunction in these patients.

METHODS

A total of 25 patients with repaired TOF prospectively underwent complete echocardiographic assessment (including DTI) of the RV and cardiopulmonary stress testing to evaluate exercise capacity. Echocardiographic variables were compared with age- and sex-matched control subjects.

RESULTS

Patients with repaired TOF had significantly lower RV DTI indices compared with control subjects. In patients with repaired TOF, RV peak systolic velocity had a significant correlation with maximal oxygen consumption during exercise (r = 0.80, P < .001) and was the only independent predictor of maximal oxygen consumption on multivariate analysis (r = 0.80, P < .001).

CONCLUSION

DTI identifies abnormalities of RV systolic and diastolic function in patients with repaired TOF. Importantly, RV systolic velocity is predictive of exercise capacity in these patients.

Natural History of Right Ventricular Dysfunction After Acute Pulmonary Embolism

BACKGROUND

Acute pulmonary embolism (PE) associated with right ventricular (RV) dysfunction has an adverse prognosis. We investigated individual parameters of RV dysfunction after acute PE, assessing their correlation with the PE extent and recovery during 6 months.

METHODS

In all, 35 patients (age 63 +/- 18 years) with acute PE were prospectively investigated for 6 months with serial echocardiography, incorporating longitudinal myocardial-velocity and strain imaging. The extent of PE was quantified on day 1 by ventilation/perfusion pulmonary scintigraphy with PE defined as large when there was greater than 30% lung involvement.

RESULTS

PE extent correlated strongly with a number of parameters of RV function, and the strongest univariate correlates were tricuspid annular motion (TAM) (r = -0.65, P < .0001) and the ratio of RV apical to RV basal systolic velocity (r = 0.66, P < .0001). Multivariate analysis identified TAM (P < .0001) and RV basal late-diastolic velocity (P = .01) as independently predicting PE extent, with a combined correlation (R2 = 0.52, P < .0001). A TAM of less than 2.0 cm had sensitivity, specificity, and positive- and negative-predictive values of 75%, 84%, 75%, and 79%, respectively, in predicting large PE. Prospective follow-up identified that RV:left ventricular end-diastolic area ratio returned to normal within 6 weeks, whereas TAM and ratio of RV apical to RV basal systolic velocity normalized after 3 to 6 months.

CONCLUSION

TAM and ratio of RV apical to RV basal systolic velocity are useful indicators of the extent of PE, and provide unique insights into the recovery of RV function after acute PE.

Right Ventricular Tissue Doppler and Strain Imaging: Ready for Clinical Use?

Although tissue Doppler (TD) imaging of the left ventricle is now commonly used in clinical settings, TD imaging of the right ventricle (RV) is not routinely practiced. Yet, there are significant data on clinical uses of RV TD imaging, including established normal values using both color and spectral TD. In acute left ventricular (LV) inferior wall myocardial infarction, depressed RV TD velocities have been shown to correlate with the presence of RV impairment, and with patient outcome. In patients with LV heart failure, TD imaging has been correlated to RV ejection fraction by radionuclide angiography, and is an independent predictor of outcome. In patients with congenital heart disease, RV TD has been especially valuable for assessing RV function, and has been correlated to invasive hemodynamic indices, and RV ejection fraction by magnetic resonance imaging. The RV performance (Tei) index has been calculated and validated using TD-derived, rather than conventional pulsed Doppler time intervals. RV TD indices have been shown to be useful in the detection of subclinical and clinical disease in morbid obesity, chronic pulmonary, and systemic disease. TD-derived RV strain imaging can detect segmental myocardial dysfunction, overcoming limitations to conventional TD imaging resulting from tethering. For both TD velocity and strain imaging, however, appreciation of the limitations of these techniques is necessary for their appropriate use. Given its rapid acquisition times, reproducibility, and ease of addition to standard transthoracic echocardiographic protocols, RV TD and strain imaging are important additional modalities in the comprehensive echo-Doppler assessment of RV function.