Impact of exercise pulmonary hypertension on postoperative outcome in primary mitral regurgitation

The prognostic relevance of exercise pulmonary hypertension in cardiac and pulmonary diseases

PURPOSE OF REVIEW

In this review, we provide an overview of the prognostic implications of exPH in patients with various common cardiac and pulmonary diseases.

RECENT FINDINGS

Exercise pulmonary hypertension (exPH) has been recently re-introduced in the current European Society of Cardiology/European Respiratory Society pulmonary hypertension guidelines. Accordingly, exPH is defined as a mean pulmonary arterial pressure (mPAP)/cardiac output (CO) slope greater than 3 mmHg/l/min. Key considerations for this re-introduction included increasing understanding on normal pulmonary hemodynamics during exercise and the broadly available evidence on the association of an abnormal mPAP/CO slope with poor survival in the general population and in different disease entities.

SUMMARY

Exercise (patho-)physiology has opened a new field for clinical research facilitating recognition of cardiovascular and pulmonary vascular diseases in an early stage. Such early recognition with significant prognostic and possibly therapeutic relevance, but being undetectable at rest, makes exercise pulmonary hemodynamics particularly interesting for common diseases, such as valvular heart disease, left heart disease, and chronic pulmonary disease.

Pulmonary Hypertension in Left Ventricular Valvular Diseases: A Comprehensive Review on Pathophysiology and Prognostic Value

Left ventricular (LV) valvular diseases, make up one of the most common etiologies for pulmonary hypertension (PH), and it is not well understood how and at which degree it affects prognosis. The aim of the present study was a comprehensive review of the pathophysiologic mechanism of PH in patients with LV valvular diseases and the prognostic value of baseline and post-intervention PH in patients undergoing interventional treatment. The pathophysiology of PH in patients with LV valvular diseases involves gradual elevation of left ventricular filling pressure and left atrial pressure, which are passively transmitted to the pulmonary circulation and raise pulmonary artery systolic pressure (PASP). A long-lasting exposure to elevated PASP progressively leads to initially functional and thereafter irreversible structural changes in the pulmonary vasculature, leading up to high pulmonary vascular resistance. Surgical treatment of severe LV valvular diseases is highly effective in patients without resting PH or those with exercise-induced PH (EIPH) before intervention. In the case of pre-operative PH, successful interventional therapy decreases PASP, but the post-operative cardiac and all-cause mortality remain higher compared to patients without pre-operative PH. Hence, it is of paramount importance to detect patients with severe LV valvulopathies before the development of PH, since they will get greater benefits from early intervention.

Quantification of primary mitral regurgitation by echocardiography: A practical appraisal

The accurate quantification of primary mitral regurgitation (MR) and its consequences on cardiac remodeling is of paramount importance to determine the best timing for surgery in these patients. The recommended echocardiographic grading of primary MR severity relies on an integrated multiparametric approach. It is expected that the large number of echocardiographic parameters collected would offer the possibility to check the measured values regarding their congruence in order to conclude reliably on MR severity. However, the use of multiple parameters to grade MR can result in potential discrepancies between one or more of them. Importantly, many factors beyond MR severity impact the values obtained for these parameters including technical settings, anatomic and hemodynamic considerations, patient's characteristics and echocardiographer' skills. Hence, clinicians involved in valvular diseases should be well aware of the respective strengths and pitfalls of each of MR grading methods by echocardiography. Recent literature highlighted the need for a reappraisal of the severity of primary MR from a hemodynamic perspective. The estimation of MR regurgitation fraction by indirect quantitative methods, whenever possible, should be central when grading the severity of these patients. The assessment of the MR effective regurgitant orifice area by the proximal flow convergence method should be used in a semi-quantitative manner. Furthermore, it is crucial to acknowledge specific clinical situations in MR at risk of misevaluation when grading severity such as late-systolic MR, bi-leaflet prolapse with multiple jets or extensive leak, wall-constrained eccentric jet or in older patients with complex MR mechanism. Finally, it is debatable whether the 4-grades classification of MR severity would be still relevant nowadays, since the indication for mitral valve (MV) surgery is discussed in clinical practice for patients with 3+ and 4+ primary MR based on symptoms, specific markers of adverse outcome and MV repair probability. Primary MR grading should be seen as a continuum integrating both quantification of MR and its consequences, even for patients with presumed “moderate” MR.

Exercise-Induced Pulmonary Hypertension: A Valid Entity or Another Factor of Confusion?

Exercise-induced pulmonary hypertension EIPH has been defined as an increase in mean pulmonary arterial pressure (mPAP) during exercise in otherwise normal values at rest. EIPH reflects heart and/or lung dysfunction and may precede the development of manifest pulmonary hypertension (PH) in a proportion of patients. It is also associated with decreased life expectancy in patients with heart failure with reduced ejection fraction (HFrEF) or left ventricle (LV) valvular diseases. Diastolic dysfunction exacerbated during exercise relates to increased LV filling pressure and left atrial pressure (LAP). In this context backward, transmitted pressure alone or accompanied with backward blood flow promotes EIPH. The gold standard of EIPH assessment remains the right heart catheterization during exercise, which is an accurate but invasive method. Alternatively, non-invasive diagnostic modalities include exercise stress echocardiography (ESE) and cardiopulmonary exercise testing (CPET). Both diagnostic tests are performed under gradually increasing physical stress using treadmill and ergo-cycling protocols. Escalating workload during the exercise is analogous to the physiological response to real exercise. The results of the latter techniques show good correlation with invasive measurements, but they suffer from lack of validation and cut-off value determination. Although it is not officially recommended, there are accumulated data supporting the importance of EIPH diagnosis in the assessment of other mild/subclinical or probably fatal diseases in patients with latent PH or heart failure or LV valvular disease, respectively. Nevertheless, larger, prospective studies are required to ensure its role in clinical practice.

Prognostic value of left atrial reservoir function in patients with severe primary mitral regurgitation undergoing mitral valve repair

AIMS

Mitral regurgitation (MR) has a significant haemodynamic impact on the left atrium. Assessment of left atrial reservoir strain (LARS) may have important prognostic implications, incremental to left atrial (LA) volume, and conventional parameters of left ventricular (LV) structure and function. This study investigated whether preoperative assessment of LARS by speckle tracking echocardiography is associated with long-term outcomes in patients undergoing mitral valve repair for severe primary MR.

METHODS AND RESULTS

Echocardiography was performed prior to mitral valve surgery in 566 patients (age 64 ± 12years, 66% men) with severe primary MR. The study population was subdivided based on a LARS value of 22%, using a spline curve analysis. The primary endpoint was all-cause mortality. During a median follow-up of 7 (4-12) years, 129 (22.8%) patients died. Patients with LARS ≤22% showed significantly higher mortality rates at 1-, 3-, and 5-year follow-up (6%, 12%, and 15%, respectively) when compared with patients with LARS >22% (2%, 3% and 5%, respectively, P < 0.001). Age [hazard ratio (HR): 1.06; 95% confidence interval (CI): 1.03-1.09; P < 0.001], LV global longitudinal strain (HR: 0.92; 95% CI: 0.87-0.98; P = 0.014), and LARS (HR: 0.96; 95% CI: 0.93-0.99; P = 0.014) were independently associated with all-cause mortality.

CONCLUSION

Preoperative LARS is independently associated with all-cause mortality in patients undergoing mitral valve repair for primary MR and provides incremental prognostic value over LA volume. LARS might be helpful to guide timing of mitral valve surgery in patients with severe primary MR.

The prognostic value of exercise-induced pulmonary hypertension in asymptomatic patients with primary mitral regurgitation

BACKGROUND

We examined whether the early development of exercise-induced pulmonary hypertension (EIPH) and right ventricular dysfunction during exercise stress echocardiography (ESE) may predict clinical deterioration in so-called "asymptomatic" patients with primary, at least moderate mitral regurgitation (MR).

METHODS

79 consecutive patients underwent a symptom-limited, graded ESE protocol on semi-supine bicycle at the beginning of the study. During the test, we assessed symptom development, test duration, and the following echocardiographic parameters: MR severity, maximum velocity of the tricuspid regurgitation jet (TR Vmax), pulmonary artery systolic pressure (PASP), and tricuspid annulus systolic excursion (TAPSE). All patients were then followed-up for at least 12 months for clinical end-points (heart failure-related symptoms requiring pharmaceutical therapy, heart failure hospitalization, and/or mitral valve surgery in case of refractory symptoms).

RESULTS

After 16 ± 4 months of follow-up, 75 patients completed the study; 26 of them achieved any clinical end-point and were classified as 'high-risk', while the rest (49 patients) were assigned to the 'low-risk' group. High-risk group showed significantly higher exercise-induced TR Vmax and PASP levels at maximum workload of ESE than low-risk counterparts (p<0.001). Based on receiver operating characteristic analysis, the early (within the first two stages of ESE or up to 50 W) steep rise of calculated PASP ≥51 mmHg (TR Vmax ≥3.4 m/s) had a 92.3% sensitivity and 100% specificity to predict clinical deterioration within the following year. That cut-off value seemed superior predictor than peak value of PASP at the end of ESE. TAPSE levels during ESE did not add prognostic value in our sample.

CONCLUSION

This is the first study demonstrating that the early development of EIPH has prognostic value in asymptomatic patients with primary at least moderate MR and may become a new valid determinant of mitral valve surgery. Additional larger prospective studies are needed to validate our findings.

Prognostic Value of Peak Exercise Systolic Pulmonary Arterial Pressure in Asymptomatic Primary Mitral Valve Regurgitation

BACKGROUND

The contribution of exercise echocardiography in primary asymptomatic mitral regurgitation (MR) remains debated. The aim of this study was to gain evidence regarding its usefulness in this setting and to investigate the prognostic value of peak exercise systolic pulmonary artery pressure (SPAP).

METHODS

One hundred seventy-seven patients (mean age, 56 ± 13 years; 69% men) with moderate to severe (grade 3+) or severe (grade 4+) degenerative MR and preserved left ventricular ejection fraction, in sinus rhythm, referred for clinically indicated exercise echocardiography were identified. The end point, MR-related events, was a composite of all-cause death or occurrence of symptoms, heart failure, atrial fibrillation, left ventricular ejection fraction < 60%, left ventricular end-systolic diameter ≥ 45 mm, or resting SPAP > 50 mm Hg.

RESULTS

At rest, effective regurgitant orifice area was 48 ± 16 mm², regurgitant volume 74 ± 26 mL, and SPAP 32 ± 7 mm Hg, and MR was severe in 138 patients (78%). Peak exercise SPAP was 55 ± 10 mm Hg. Positive results on exercise testing motivated surgery in 26 patients, 11 underwent prophylactic surgery, 10 were lost to follow-up, and 130 were included in the outcome analysis. During a follow-up period of 19 ± 7 months, 31 MR-related events (24%) were reported. Peak exercise SPAP was predictive of outcomes in univariate analysis (P = .01) and after adjustment for age, gender, MR severity, and resting SPAP (P < .05). Peak exercise SPAP ≥ 50 mm Hg was associated with worse event-free survival (hazard ratio, 5.24; 95% CI, 1.77-15.53; P = .003), but not the threshold of ≥60 mm Hg proposed in previous guidelines (hazard ratio, 1.70; 95% CI, 0.71-4.03; P = .24).

CONCLUSIONS

The present findings support the use of exercise echocardiography for risk stratification in patients with asymptomatic primary MR and suggest a lower peak exercise SPAP threshold (50 mm Hg) than previously recommended to define the timing of intervention. Prospective studies are needed to confirm these findings.

Clinical application of stress echocardiography for valvular heart disease

Stress echocardiography is widely used to assess several cardiovascular diseases, including ischemic heart disease, valvular heart disease (VHD), heart failure, congenital heart disease, and pulmonary hypertension. In valvular heart disease with asymptomatic severe or symptomatic non-severe status, stress echocardiography plays a central role in the management. As of 2017, the updated American College of Cardiology/American Heart Association and European Society of Cardiology/European Association for Cardio-Thoracic Surgery VHD guidelines recommended stress testing to (1) confirm symptoms and (2) evaluate the hemodynamic response to exercise. In patients with undetermined VHD severity in the presence of low-flow status, it can also be helpful to determine whether the VHD is severe based on flow-dependent changes in response to stress. The clinical indications of stress echocardiography in VHD have expanded with growing evidence for prognosis and being an early marker for interventions. As a result, demand has increased in major cardiology societies for the standardization of stress echocardiography in VHD. Echocardiographic centers should be aware of the clinical potential of stress echocardiography to ensure its optimal application and performance in VHD. This article reviews the clinical application of stress echocardiography, including dobutamine, semisupine bicycle, treadmill, and leg-positive pressure for VHD patient management, and focuses on the current consensus regarding the use of stress echocardiography in VHD. Stress echocardiography is safe and should be encouraged, especially in heart valve clinics, to understand the complex mechanism in asymptomatic patients.

The Right Heart-Pulmonary Circulation Unit and Left Heart Valve Disease

Valvular heart disease (VHD) is frequently accompanied by pulmonary hypertension (PH). In asymptomatic patients, PH is rare, although the exact prevalence is unknown and mainly stems from the severity of the VHD and the presence of diastolic dysfunction. PH can also be depicted during exercise echocardiography. PH either at rest or during exercise is also a powerful determinant of outcome and is independently associated with reduced survival, regardless of the severity of the underlying valvular pathology. Therefore, because PH is a marker of poor prognosis, assessment of PH in VHD is crucial for risk stratification and management of patients with VHD.

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.

Systolic pulmonary artery pressure assessed during routine exercise Doppler echocardiography: insights of a real-world setting in patients with elevated pulmonary pressures

Pulmonary hypertension is a marker of disease severity. Exercise Doppler echocardiography (EDE) has proven to be feasible and reliable to assess pulmonary pressure. Increase in systolic pulmonary artery pressure (sPAP) has diagnostic and prognostic value in controlled studies. However, its value when assessed during routine examination in patients with cardiopulmonary diseases and resting sPAP > 35 mmHg is not clearly defined. Clinical documentation and offline reevaluation of digitally stored EDE examinations of patients with appropriate clinical indications for EDE were analyzed. N = 278 patients with sPAP at rest > 35 mmHg met inclusion criteria. One patient was lost to follow-up. Mean age of patients was 72 ± 10 years, 178 (64%) of the study population were men. There were no relevant differences among survivors and non-survivors concerning comorbidities. Exercise performance (3.6 ± 1.2 vs. 4.9 ± 1.4 MET, p < 0.001) was lower, whereas sPAP during exercise was higher (67.3 ± 14.7 vs. 62.1 ± 13.2 mmHg, p = 0.027) in non-survivors. Univariate predictors of all-cause mortality were NYHA functional class III (HR = 2.56, p < 0.001), ≥ 2-vessels coronary artery disease (CAD) (HR = 1.93, p = 0.04), left atrial diameter > 45 mm (HR = 2.58, p < 0.001), rest sPAP > 42 mmHg (HR = 1.94, p = 0.010) and ΔsPAP increase ≥ 0.23 mmHg/Watt (HF = 1.92, p = 0.010). After multivariate analysis, NYHA functional class III (HR = 2.35, p < 0.001), LA diameter (HR = 2.28, p = 0.003) and sPAP increase ≥ 0.23 mmHg/Watt (HF = 2.19, p = 0.002) remained significant predictors of mortality, whereas a double product (HR = 0.42, p = 0.005) was associated with better prognosis. sPAP assessment during routine EDE provides relevant prognostic information comparable to findings in studies in selected populations. A higher sPAP increase at lower exercise performance shows significant association with increased of mortality.

Stress echocardiography in contemporary clinical cardiology: practical considerations and accreditation

Stress echocardiography is a widely utilised test in patients with known or suspected coronary artery disease (CAD), valvular heart disease and cardiomyopathies. Its advantages include the ubiquitous availability of echocardiography, lack of ionising radiation, choice of physiological or pharmacological stressors, good diagnostic accuracy and robust supporting evidence base. SE has evolved significantly as a technique over the past three decades and has benefitted considerably from improvements in overall image quality (superior resolution), machine technology (e.g. digital cine-loop acquisition and side-by-side image display) and development of second-generation ultrasound contrast agents that have improved reader confidence and diagnostic accuracy. The purpose of this article is to review the breadth of SE in contemporary clinical cardiology and discuss the recently launched British Society of Echocardiography (BSE) Stress Echocardiography accreditation scheme.

Variable Hemodynamic Responses during Diastolic Stress Echocardiography in Patients Who Have Relaxation Abnormality with Possible Elevated Filling Pressure

BACKGROUND AND OBJECTIVES

The clinical characteristics of patients with diastolic dysfunction characterized by a relaxation abnormality with possible elevated filling pressure is remain to be determined. We sought to test whether diastolic stress echocardiography (DSE) is useful for characterization of these patients.

METHODS

A total of 120 patients (58 men, mean age of 64±7 years) with E/A ratio <1.0 (mean±SD, 0.7±0.1) and 10≤ E/e' <15 at rest echocardiography was enrolled prospectively for supine bicycle exercise up to 50 W.

RESULTS

During exercise, 47 patients (39%) showed high left ventricular filling pressure (E/e' >15, hLVFP) and 40 (30%) developed exercise-induced pulmonary hypertension (systolic pulomary arterial pressure >50 mmHg, EiPH) without hLVFP. The remaining 33 patients did not show hLVFP or EiPH. The incidence of EiPH with hLVFP was 21% (25/120). By multivariate analysis, age (odds ratio [OR], 1.07; 95% confidence interval [CI], 1.00-1.13; p=0.039) and systolic pulmonary artery pressure at rest (OR, 1.14; 95% CI, 1.02-1.27; p=0.02) were associated with EiPH, whereas late diastolic transmitral velocity (OR, 1.04; 95% CI, 1.00-1.08; p=0.03) and diastolic blood pressure (OR, 0.94; 95% CI, 0.90-0.99; p=0.02) were associated with hLVFP during exercise.

CONCLUSIONS

Patients with relaxation abnormality and possibly hLVFP showed markedly heterogeneous hemodynamic changes during low-level exercise and DSE was useful to characterize these patients.

Stress echocardiography in patients with native valvular heart disease

Valve stress echocardiography (VSE) can be performed as exercise stress echocardiography (ESE) or dobutamine stress echocardiography (DSE) depending on the patient’s clinical status, severity and type of valve disease. ESE combines exercise testing with two-dimensional grey scale and Doppler echocardiography during exercise. Thus, it provides objective assessment of symptomatic status (exercise test), as well as exercise-induced changes of a series of echocardiographic parameters (different depending on the valve disease type), which yield prognostic information in individual patients and help in a better treatment planning. DSE is useful in symptomatic patients with low-gradient aortic stenosis. It clarifies its severity and helps in assessing surgical risk in patients with severe disease and systolic dysfunction. It can be also used to test valve haemodynamics in asymptomatic patients with significant mitral stenosis unable to perform an exercise test or to test the left ventricle response, namely to test viability, in patients with ischaemic secondary mitral regurgitation. VSE has taught us that history taking, clinical examination and resting echocardiography give an ‘incomplete picture’ of the disease in patients presenting with a severe valve disease. Therefore, its use should be encouraged in such patients.

Right ventricular exercise contractile reserve and outcomes after early surgery for primary mitral regurgitation

Objective

To assess if the lack of development of right ventricular (RV) contractile reserve during exercise echocardiography (ex-echo) might be a predictor of postoperative major adverse cardiovascular events (MACEs) in patients with primary mitral regurgitation (pMR) undergoing early surgery.

Methods

Comprehensive resting and ex-echo were performed in 142 asymptomatic patients (58±21 years, 68% men, New York Heart Association functional class ≤2) with isolated severe pMR and preserved left ventricular (LV) function (LV ejection >60%, LV end-systolic diameter <45 mm) undergoing mitral valve replacement (n=20) or repair. Postoperative MACEs were defined as occurrence of atrial fibrillation, stroke, cardiac-related hospitalisation or death. RV function was evaluated at rest in every patient during ex-echo by measuring their tricuspid annular plane systolic excursion (TAPSE) value.

Results

After median follow-up of 30 months (IQR 16–60 months), MACEs occurred in 48 (34%) patients. Using Bayesian model averaging, among all the characteristics including the type of surgery, exercise TAPSE (ex-TAPSE) emerged as the most likely predictor of prognosis (HR 0.91, 95% CI 0.86 to 0.96). Other probable predictors were exercise fractional area change (HR 0.02, 95% CI 0.00 to 0.80), male gender (HR 0.40, 95% CI 0.21 to 0.75) and RV basal diameter (HR 1.06, 95% CI 0.98 to 1.14). In the receiver operating characteristic curve analysis, an ex-TAPSE value of <26 mm (sensitivity 73% (95% CI 61 to 84) and specificity of 86% (95% CI 77% to 93%)) defined RV dysfunction. Event-free survival at 5 years was significantly lower in the patient group that exhibited no development of RV contractile reserve during exercise: 43.9% (95% CI 31.3 to 61.4) vs 75.8% (95% CI 64.8 to 88.7).

Conclusion

Lack of development of exercise-induced RV contractile reserve is a prognostic predictor in patients with severe pMR undergoing early mitral valve surgery.

Exercise Testing in Mitral Regurgitation

Mitral regurgitation (MR) is the second most common valvular heart disease referred for corrective surgery. Diagnostic and management dilemmas are not uncommon when dealing with MR patients. Exercise testing plays an important role in sorting out some of these clinical challenges. In primary asymptomatic MR, exercise testing allows symptom assessment, confident link of symptoms to valve disease severity, safe deferral of surgery for the next 1-year in patients with preserved exercise capacity, insights into the mechanism of exercise-induced dyspnea and helps in individual risk stratification. Moreover, exercise testing in the form of exercise stress echocardiography is also useful in the evaluation of patients with secondary ischemic MR for risk stratification as well as for the detection of patients with moderate ischemic MR in whom mitral valve repair at the time of surgical revascularization may add benefit.

Timing surgery in mitral regurgitation: defining risk and optimising intervention using stress echocardiography

Mitral regurgitation (MR) is the second most common form of valvular disease requiring surgery. Correct identification of surgical candidates and optimising the timing of surgery are key in management. For primary MR, this relies upon a balance between the peri-operative risks and rates of successful repair in patients undergoing early surgery when asymptomatic with the potential risk of irreversible left ventricular dysfunction if intervention is performed too late. For secondary MR, recognition that this is a highly dynamic condition where MR severity may change is key, although data on outcomes in determining whether concomitant valve intervention is performed with revascularisation has raised questions regarding timing of surgery. There has been substantial interest in the use of stress echocardiography to risk stratify patients in mitral regurgitation. This article reviews the role of stress echocardiography in both primary and secondary mitral regurgitation and discusses how this can help clinicians tackle the challenges of this prevalent condition.

Epidemiology of Pulmonary Hypertension in Left Heart Disease

Pulmonary hypertension (PH) in the setting of left side heart disease is associated with adverse outcomes. The exact prevalence of PH in the different pathologies that affect the left ventricle, however, is difficult to access with the current literature. The lack of a standard definition of PH in older studies, the different modalities to assess pulmonary artery pressures and the varying disease severity, all account for the great variability in the reported prevalence of PH. PH can accompany heart failure (HF) with reduced (HFrEF) or preserved ejection fraction (HFpEF) as well as mitral and aortic valve disease; in any of these instances it is important to recognize whether the elevation of pulmonary pressures is driven by elevated left ventricular pressures only (isolated post-capillary PH) or if there is an accompanying remodeling component in the pulmonary arterioles (combined post-capillary and pre-capillary PH). The objective of this review is to describe the definitions, prevalence and the risk factors associated with the development of PH in the setting of HFrEF, HFpEF and valvular heart disease.

Pulmonary Hypertension in Aortic Stenosis and Mitral Regurgitation: Rest and Exercise Echocardiography Significance

Valvular heart disease is a common cause of increased mean pulmonary artery pressure (PAP). Aortic stenosis and mitral regurgitation are frequently accompanied by pulmonary hypertension (PH), especially when they are severe and symptomatic. In asymptomatic patients, PH is rare, though the exact prevalence is unknown and mainly stems from the severity of the valvular heart disease and the presence of diastolic dysfunction. Exercise echocardiography has recently gained interest in depicting PH. In these asymptomatic patients, exercise PH is observed in about >40%. Either PH at rest (systolic PAP >50 mmHg) or during exercise (systolic PAP >60 mmHg) is a powerful determinant of outcome and is independently associated with reduced survival, regardless of the severity of the underlying valvular pathology.

Stress echocardiography: what is new and how does it compare with myocardial perfusion imaging and other modalities?

Cardiovascular disease is a leading cause of morbidity and mortality, and noninvasive strategies to diagnose and risk stratify patients remain paramount in the evaluative process. Stress echocardiography is a well-established, versatile, real-time imaging modality with advantages including lack of radiation exposure, portability, and affordability. Innovative techniques in stress echocardiography include myocardial contrast echocardiography, deformation imaging, three-dimensional (3D) echocardiography, and assessment of coronary flow reserve. Myocardial perfusion imaging with single-photon emission computed tomography (SPECT) or positron emission tomography (PET) are imaging alternatives, and stress cardiac magnetic resonance imaging and coronary computed tomography (CT) angiography, including CT perfusion imaging, are emerging as newer approaches. This review will discuss recent and upcoming developments in the field of stress testing, with an emphasis on stress echocardiography while highlighting comparisons with other modalities.