Time course of restoration of systolic and diastolic right ventricular function after pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension

Pulmonary Vein Sign on Computed Tomography Pulmonary Angiography in Proximal and Distal Chronic Thromboembolic Pulmonary Hypertension With Hemodynamic Correlation

BACKGROUND

Pulmonary vein sign (PVS) indicates abnormal pulmonary venous flow on computed tomography pulmonary angiography (CTPA) is a frequent finding in proximal chronic thromboembolic pulmonary hypertension (CTEPH). PVS's occurrence in distal CTEPH and correlation to disease severity is unknown. Using right heart catheterization data, we evaluated the relationship between PVS and CTEPH disease distribution and severity.

MATERIALS AND METHOD

A total of 93 consecutive CTEPH cases with both CTPA and right heart catheterization were identified in this retrospective multi-institutional study. After excluding 17 cases with suboptimal CTPA, there were 52 proximal and 24 distal CTEPH cases. Blood flow in the major pulmonary veins was graded qualitatively. Subgroup analysis of PVS was performed in 38 proximal CTEPH cases before and after pulmonary endarterectomy.

RESULTS

PVS was more frequent in proximal (79%) than distal CTEPH (29%) ( P <0.001). No significant difference was noted in invasive mean pulmonary artery pressure (46±11 and 41±12 mm Hg) or pulmonary vascular resistance (9.4±4.5 and 8.4±4.8 WU) between the 2 groups. In the subgroup analysis, PVS was present in 29/38 patients (76%) before surgery. Postoperatively, 33/38 cases (87%, P <0.001) had normal venous flow (mean pulmonary artery pressure 46±11 and 25; pulmonary vascular resistance 9.2±4.3 and 2.6 WU preop and postop, respectively).

CONCLUSION

PVS is a common feature in proximal but infrequent findings in distal CTEPH. PVS does not correlate with hemodynamic severity. PVS resolution was seen in the majority of patients following successful endarterectomy.

A Comprehensive Assessment of Right Ventricular Function in Chronic Thromboembolic Pulmonary Hypertension

While chronic thromboembolic pulmonary hypertension (CTEPH) results from macroscopic and microscopic obstruction of the pulmonary vascular bed, the function of the right ventricle (RV) and increased RV afterload are the main determinants of its symptoms and prognosis. In this review, we assess RV function in patients diagnosed with CTEPH with a focus on the contributions of RV afterload and dysfunction to the pathogenesis of this disease. We will also discuss changes in RV function and geometry in response to treatment, including medical therapy, pulmonary endarterectomy, and balloon pulmonary angioplasty.

Different response of the oxygen pathway in patients with chronic thromboembolic pulmonary hypertension treated with pulmonary endarterectomy versus balloon pulmonary angioplasty

Background

Oxygen pathway limitation exists in chronic thromboembolic pulmonary hypertension (CTEPH). Pulmonary endarterectomy (PEA) and balloon pulmonary angioplasty (BPA) are two effective interventions for CTEPH, but their effects and comparison of these two interventions on the oxygen pathway are not well demonstrated.

Methods

CTEPH patients with available pulmonary function test, hemodynamics, and blood gas analysis before and after the interventions were included for comparison of oxygen pathway in terms of lung ventilation, lung gas exchange, oxygen delivery, and oxygen extraction between these two interventions.

Results

The change in the percentage of the predicted forced expiratory volume in the 1 s (−3.4 ± 12.7 vs. 3.8 ± 8.7%, P = 0.006) and forced vital capacity (−5.5 ± 13.0 vs. 4.2 ± 9.9%, P = 0.001) among the PEA group (n = 24) and BPA group (n = 46) were significantly different. Patients in the PEA group had a significant increase in their arterial oxygen saturation (from 92.5 ± 3.6 to 94.6 ± 2.4%, P = 0.022), while those in the BPA group had no change, which could be explained by a significant improvement in ventilation/perfusion (−0.48 ± 0.53 vs. −0.17 ± 0.41, P = 0.016). Compared with patients post-BPA, patients post-PEA were characterized by higher oxygen delivery (756.3 ± 229.1 vs. 628.8 ± 188.5 ml/min, P = 0.016) and higher oxygen extraction (203.3 ± 64.8 vs. 151.2 ± 31.9 ml/min, P = 0.001).

Conclusion

Partial amelioration of the oxygen pathway limitations could be achieved in CTEPH patients treated with PEA and BPA. CTEPH patients post-PEA had better performance in lung gas exchange, oxygen delivery, and extraction, while those post-BPA had better lung ventilation. Cardiopulmonary rehabilitation may assist in improving the impairment of the oxygen pathway.

Evaluating the Right Ventricle in Acute and Chronic Pulmonary Embolism: Current and Future Considerations

The right ventricle (RV), due to its morphologic and physiologic differences, is susceptible to sudden increase in RV afterload, as noted in patients with acute pulmonary embolism (PE). Functional impairment of RV function is a stronger presage of adverse outcomes in acute PE than the location or burden of emboli. While current iterations of most clinical prognostic scores do not incorporate RV dysfunction, advancements in imaging have enabled more granular and accurate assessment of RV dysfunction in acute PE. RV enlargement and dysfunction on imaging is noted only in a subset of patients with acute PE and is dependent on underlying cardiopulmonary reserve and clot burden. Specific signs like McConnell's and "60/60" sign are noted in less than 20% of patients with acute PE. About 2% of patients with acute PE develop chronic thromboembolic pulmonary hypertension, characterized by continued deterioration in RV function in a subset of patients with a continuum of RV function from preserved to overt right heart failure. Advances in molecular and other imaging will help better characterize RV dysfunction in this population and evaluate the response to therapies.

Limitations of right ventricular annular parameters in the early postoperative period following pulmonary endarterectomy: an observational study

OBJECTIVES

Echocardiographic right ventricular (RV) annular parameters are probably not as reliable to evaluate the surgical success in the postoperative period after pulmonary endarterectomy (PEA), whereas RV end-diastolic/left ventricular end-diastolic area ratio (RVEDA/LVEDA ratio) could be more useful. This study examined the relationship between RV annular parameters or RVEDA/LVEDA ratio and ideal cardiac index (ICI), before and after PEA.

METHODS

Among 80 patients who underwent PEA, the relationships between RVEDA/LVEDA ratio (21 patients), or tricuspid annular plane systolic excursion (32 patients), or systolic tricuspid annular velocity (55 patients) and ICI were modelled.

RESULTS

Forty-eight hours following PEA, mean pulmonary artery pressure decreased (26 ± 6 vs 46 ± 12 mmHg, P < 0.0001) and ICI improved (2.8 ± 0.8 vs 3.0 ± 0.9 l/min/m2, P = 0.02). In contrast to the moderate association between RV annular indices and ICI in the preoperative period, no significant relationship was found in the postoperative period (r = 0.54 and 0.17 for tricuspid annular plane systolic excursion and r = 0.46 and 0.16 for systolic tricuspid annular velocity, respectively). The RVEDA/LVEDA ratio significantly decreased postoperatively (0.97 ± 0.21 vs 1.19 ± 0.43, P = 0.002) and was correlated with ICI both in preoperative and postoperative periods (r = 0.57 and 0.57, respectively). There was a significant correlation between changes in RVEDA/LVEDA ratio and changes in total pulmonary resistance.

CONCLUSIONS

Improved ICI and RVEDA/LVEDA ratio reflected the surgical success of PEA and lowering of total pulmonary resistances. In contrast to the RV/left ventricular area ratio, annular RV indices associated poorly with postoperative ICI. Recognizing this limitation is important in minimizing the overdiagnosis of RV dysfunction after PEA.

Effects of pulmonary endarterectomy on pulmonary hemodynamics in chronic thromboembolic pulmonary hypertension, evaluated by interventricular septum curvature

The interventricular septum curvature, measured in images of electrocardiogram-gated 320-slice multidetector computed tomography, is reportedly useful and less invasive than right heart catheterization, as it could provide clues regarding pulmonary arterial pressure in patients with chronic thromboembolic pulmonary hypertension. Although pulmonary endarterectomy is an efficient treatment for chronic thromboembolic pulmonary hypertension, the interventricular septum curvature in patients who have received pulmonary endarterectomy has not been evaluated. We evaluated whether the interventricular septum curvature on electrocardiogram-gated 320-slice multidetector computed tomography can predict pulmonary hemodynamics in chronic thromboembolic pulmonary hypertension even after pulmonary endarterectomy. We studied 40 patients with chronic thromboembolic pulmonary hypertension (60.5 ± 9.7 years; 30 females), who underwent pulmonary endarterectomy at Chiba University Hospital between December 2010 and July 2018. To measure the interventricular septum curvature, we prepared left ventricular short-axis tomographic images from 4D images of electrocardiogram-gated 320-slice multidetector computed tomography. We calculated the radius of interventricular septum and determined the interventricular septum curvature in both the systolic and diastolic phases. We compared the interventricular septum curvature with pulmonary hemodynamics measured by right heart catheterization before and after pulmonary endarterectomy. After pulmonary endarterectomy, the correlations of the interventricular septum curvature with mean pulmonary arterial pressure, systolic pulmonary arterial pressure, and pulmonary vascular resistance disappeared, although the interventricular septum curvature was correlated with these pulmonary hemodynamic parameters before pulmonary endarterectomy. Changes in systolic interventricular septum curvature revealed significant correlations with changes in mean pulmonary arterial pressure, systolic pulmonary arterial pressure and pulmonary vascular resistance. Diastolic interventricular septum curvature also showed significant correlations with preoperative pulmonary hemodynamics, but not with postoperative pulmonary hemodynamics. Changes in the interventricular septum curvature after pulmonary endarterectomy could estimate the efficacy of pulmonary endarterectomy, although the interventricular septum curvature after pulmonary endarterectomy showed no significant correlations with pulmonary hemodynamics. Additionally, our findings confirmed that the interventricular septum curvature before pulmonary endarterectomy could be used to evaluate the severity of disease.

Assessment of Right Ventricular Function in the Research Setting: Knowledge Gaps and Pathways Forward. An Official American Thoracic Society Research Statement

BACKGROUND

Right ventricular (RV) adaptation to acute and chronic pulmonary hypertensive syndromes is a significant determinant of short- and long-term outcomes. Although remarkable progress has been made in the understanding of RV function and failure since the meeting of the NIH Working Group on Cellular and Molecular Mechanisms of Right Heart Failure in 2005, significant gaps remain at many levels in the understanding of cellular and molecular mechanisms of RV responses to pressure and volume overload, in the validation of diagnostic modalities, and in the development of evidence-based therapies.

METHODS

A multidisciplinary working group of 20 international experts from the American Thoracic Society Assemblies on Pulmonary Circulation and Critical Care, as well as external content experts, reviewed the literature, identified important knowledge gaps, and provided recommendations.

RESULTS

This document reviews the knowledge in the field of RV failure, identifies and prioritizes the most pertinent research gaps, and provides a prioritized pathway for addressing these preclinical and clinical questions. The group identified knowledge gaps and research opportunities in three major topic areas: 1) optimizing the methodology to assess RV function in acute and chronic conditions in preclinical models, human studies, and clinical trials; 2) analyzing advanced RV hemodynamic parameters at rest and in response to exercise; and 3) deciphering the underlying molecular and pathogenic mechanisms of RV function and failure in diverse pulmonary hypertension syndromes.

CONCLUSIONS

This statement provides a roadmap to further advance the state of knowledge, with the ultimate goal of developing RV-targeted therapies for patients with RV failure of any etiology.

Evaluation and Management of Right-Sided Heart Failure: A Scientific Statement From the American Heart Association

Background and Purpose:

The diverse causes of right-sided heart failure (RHF) include, among others, primary cardiomyopathies with right ventricular (RV) involvement, RV ischemia and infarction, volume loading caused by cardiac lesions associated with congenital heart disease and valvular pathologies, and pressure loading resulting from pulmonic stenosis or pulmonary hypertension from a variety of causes, including left-sided heart disease. Progressive RV dysfunction in these disease states is associated with increased morbidity and mortality. The purpose of this scientific statement is to provide guidance on the assessment and management of RHF.

Methods:

The writing group used systematic literature reviews, published translational and clinical studies, clinical practice guidelines, and expert opinion/statements to summarize existing evidence and to identify areas of inadequacy requiring future research. The panel reviewed the most relevant adult medical literature excluding routine laboratory tests using MEDLINE, EMBASE, and Web of Science through September 2017. The document is organized and classified according to the American Heart Association to provide specific suggestions, considerations, or reference to contemporary clinical practice recommendations.

Results:

Chronic RHF is associated with decreased exercise tolerance, poor functional capacity, decreased cardiac output and progressive end-organ damage (caused by a combination of end-organ venous congestion and underperfusion), and cachexia resulting from poor absorption of nutrients, as well as a systemic proinflammatory state. It is the principal cause of death in patients with pulmonary arterial hypertension. Similarly, acute RHF is associated with hemodynamic instability and is the primary cause of death in patients presenting with massive pulmonary embolism, RV myocardial infarction, and postcardiotomy shock associated with cardiac surgery. Functional assessment of the right side of the heart can be hindered by its complex geometry. Multiple hemodynamic and biochemical markers are associated with worsening RHF and can serve to guide clinical assessment and therapeutic decision making. Pharmacological and mechanical interventions targeting isolated acute and chronic RHF have not been well investigated. Specific therapies promoting stabilization and recovery of RV function are lacking.

Conclusions:

RHF is a complex syndrome including diverse causes, pathways, and pathological processes. In this scientific statement, we review the causes and epidemiology of RV dysfunction and the pathophysiology of acute and chronic RHF and provide guidance for the management of the associated conditions leading to and caused by RHF.

Evaluation of the Clinical Utility of Transesophageal Echocardiography and Invasive Monitoring to Assess Right Ventricular Function During and After Pulmonary Endarterectomy

OBJECTIVE

Patients undergoing pulmonary endarterectomy (PEA) have impaired right ventricular function. The authors sought to assess the clinical utility of commonly used perioperative echocardiographic and right heart catheter measurements in patients undergoing PEA.

DESIGN

A single-center prospective observational study.

SETTING

The study was conducted in a quaternary care cardiac surgical center in the United Kingdom.

PARTICIPANTS

Patients undergoing PEA between April 2015 and January 2016.

INTERVENTIONS

Thermodilution cardiac index and echocardiography variables were measured at 3 time points: before sternotomy (T1), after pericardial incision (T2), and after sternal closure (T3). Six-month follow-up echocardiography and 6-minute walk (6-MWT) test were performed.

MEASUREMENTS AND MAIN RESULTS

Fifty patients were recruited and complete data sets were available for 41 patients. Tricuspid annular plane systolic excursion declined after pericardial incision and cardiopulmonary bypass (T1: 15 ± 4 mm, T2: 13 ± 4 mm, T3: 7 ± 2 mm; p < 0.0001), returning to baseline 6 months postoperatively. Cardiac index (T1: 2.5 ± 0.7 L/min/m², T2: 2.6 ± 0.6 L/min/m², T3: 2.3 ± 0.5 L/min/m²; p = 0.07) and right ventricular fractional area change (T1: 36 ± 11%, T2: 40 ± 12%, T3: 40 ± 9%; p = 0.12) were preserved perioperatively. 6-MWT improved from baseline (294 ± 111 m) to follow-up (357 ± 107 m) (p < 0.001). Pulmonary vascular resistance at T3 correlated moderately with follow-up 6-MWT (R = -0.60).

CONCLUSIONS

In patients undergoing PEA, invasive measurements and echocardiography assessment of right ventricular function are not interchangeable. Tricuspid annular plane systolic excursion is not a reliable measure of right ventricular function perioperatively. Pulmonary vascular resistance shows moderate correlation with postoperative functional capacity.

Case report: Subjective loss of performance after pulmonary embolism in an athlete- beyond normal values

Background

Chronic thromboembolic pulmonary hypertension (CTEPH) is a progressive disease. For patients with operable CTEPH, there is a clear recommendation for surgical removal of persistent thrombi by pulmonary endarterectomy (PEA). However, without the presence of PH, therapeutic management of chronic thromboembolic disease (CTED) is challenging - especially in highly trained subjects exceeding predicted values of maximal exercise capacity.

Case presentation

A 43-year-old male athlete reported with progressive exercise limitation since 8 months. Six months earlier, pulmonary embolism had occurred, and was treated since with oral anticoagulation. A pulmonary ventilation/perfusion scan showed severe ventilation/perfusion mismatch: chest CT and pulmonary angiography revealed bilateral wall-adherent thrombotic material, but pulmonary hemodynamics were completely normal. His peak oxygen uptake exceeded predicted values, however exercise ventilatory efficiency was abnormal, compared to a matching athlete. After thoroughly discussing therapeutic options with the patient, he successfully underwent pulmonary endarterectomy at an expert center. Five and twelve months after surgery, his maximal exercise capacity and ventilatory efficiency profoundly improved beyond preoperative values, and his subjective exercise tolerance had returned to normal.

Conclusions

Significant CTED may be present without relevant pathologic changes in pulmonary hemodynamics at rest. Reaching normal values of maximal exercise capacity does not exclude pulmonary vascular disease in highly trained subjects. More data are needed to evaluate the risk-/benefit ratio of PEA in patients with CTED and normal pulmonary hemodynamics. A thorough discussion with the patient as well as shared decision making regarding therapy are mandatory. Cardiopulmonary exercise testing may add important clinical information in the non-invasive diagnostic evaluation at baseline and during follow-up.

Delayed recovery of right ventricular systolic function after repair of long-standing tricuspid regurgitation associated with severe right ventricular failure

After tricuspid valve surgery for long-standing tricuspid regurgitation associated with right ventricular failure, reverse remodelling of the enlarged right ventricle, including recovery of right ventricular systolic function, is unpredictable. We present the case of a 31-year old man with early reduction of dilated right ventricular dimensions and delayed recovery of impaired right ventricular systolic function after valve repair for traumatic tricuspid regurgitation lasting 16 years.

Right ventricle in acute and chronic pulmonary embolism (2013 Grover Conference series)

Venous thromboembolism (VTE) encompasses deep-vein thrombosis and pulmonary embolism (PE). It is the third-most-frequent cardiovascular disease, with an overall annual incidence of 1-2 per 1,000 population. Chronic thromboembolic pulmonary hypertension (CTEPH) is regarded as a late sequela of PE, with a reported incidence varying between 0.1% and 9.1% of those surviving acute VTE. Right ventricular (RV) function is dependent on afterload. The most precise technique to describe RV function is invasive assessment of the RV-to-pulmonary vascular coupling. However, assessments of RV afterload (i.e., steady and pulsatile flow components and their product, the RC-time) may be useful hemodynamic surrogates of coupling. RV load is different in acute and chronic PE. In acute PE, more than 60% occlusion of the cross-sectional area of the pulmonary artery within a short period of time leads to abrupt hemodynamic collapse. If the time of occlusion is limited to ∼15 seconds, significant decreases in fractional area change, tricuspid annulus systolic excursion, and RV free-wall deformation (strain) occur, with the latter showing significant postsystolic shortening. These changes have similarities to ischemic stunning, and they recover within minutes. In CTEPH, studies of pulmonary vascular resistance (PVR) and pulmonary arterial compliance demonstrated low RC-times that were further lowered after pulmonary endarterectomy (PEA). Immediate postoperative PVR was the only predictor of long-term survival/freedom from lung transplantation, suggesting that the effect of PEA on opening vascular territories to flow outweighs its effect on proximal stiffness. This review summarizes the current knowledge on vascular and intrinsic RV adaptation to VTE, including CTEPH, and the role of imaging.

Plasma brain natriuretic peptide as a biomarker for haemodynamic outcome and mortality following pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension

OBJECTIVES

In chronic thromboembolic pulmonary hypertension (CTEPH), right ventricular (RV) dysfunction is associated with increased morbidity and mortality following pulmonary endarterectomy. Plasma brain natriuretic peptide (BNP) levels were previously shown to correlate with RV (dys)function. We hypothesized that BNP can be used as a non-invasive biomarker to identify patients at 'high risk' for postoperative morbidity and mortality.

METHODS

We studied the postoperative outcome in 73 consecutive patients. Patients were divided into three groups based on previously determined cut-off levels: BNP <11.5, indicating normal RV function (ejection fraction [EF] ≥45%), BNP >48.5 pmol/l, indicating RV dysfunction (right ventricular ejection fraction <30%) and BNP 11.5-48.5 pmol/l. Postoperative 'bad outcome' was defined as the presence of either residual pulmonary hypertension (PH) or (all-cause) mortality.

RESULTS

Plasma BNP >48.5 pmol/l was shown to be an independent predictor of 'bad outcome'. Compared with BNP <11.5 pmol/l, BNP >48.5 pmol/l identified patients at higher risk for (all-cause) mortality (17 vs 0%; P = 0.009) and residual PH (56 vs 20%; P < 0.004). Also, the durations of mechanical ventilation and intensive care unit stay were significantly longer in patients with BNP >48.5 pmol/ml.

CONCLUSIONS

Plasma BNP levels may be of use as a non-invasive biomarker reflecting RV dysfunction, next to other well-recognized (invasive) parameters, for better preoperative risk stratification of CTEPH patients.