Patient-specific finite element analysis of heart failure and the impact of surgical intervention in pulmonary hypertension secondary to mitral valve disease

Pulmonary hypertension (PH), a chronic and complex medical condition affecting 1% of the global population, requires clinical evaluation of right ventricular maladaptation patterns under various conditions. A particular challenge for clinicians is a proper quantitative assessment of the right ventricle (RV) owing to its intimate coupling to the left ventricle (LV). We, thus, proposed a patient-specific computational approach to simulate PH caused by left heart disease and its main adverse functional and structural effects on the whole heart. Information obtained from both prospective and retrospective studies of two patients with severe PH, a 72-year-old female and a 61-year-old male, is used to present patient-specific versions of the Living Heart Human Model (LHHM) for the pre-operative and post-operative cardiac surgery. Our findings suggest that before mitral and tricuspid valve repair, the patients were at risk of right ventricular dilatation which may progress to right ventricular failure secondary to their mitral valve disease and left ventricular dysfunction. Our analysis provides detailed evidence that mitral valve replacement and subsequent chamber pressure unloading are associated with a significant decrease in failure risk post-operatively in the context of pulmonary hypertension. In particular, right-sided strain markers, such as tricuspid annular plane systolic excursion (TAPSE) and circumferential and longitudinal strains, indicate a transition from a range representative of disease to within typical values after surgery. Furthermore, the wall stresses across the RV and the interventricular septum showed a notable decrease during the systolic phase after surgery, lessening the drive for further RV maladaptation and significantly reducing the risk of RV failure.

Impact of systolic pulmonary artery pressure on all-cause mortality in elderly cardiac patients

OBJECTIVE

Elevated systolic pulmonary artery pressure (sPAP) is common among elderly patients with cardiac and pulmonary diseases. The lowest level of sPAP associated with increased mortality rate in octogenarians with cardiac diseases is however not sufficiently studied. Therefore, the present study aimed to identify the lowest level of sPAP associated with increased 5-year all-cause mortality in this patient group.

DESIGN

Of 538 octogenarians presented at the three Sahlgrenska University Hospitals (Sahlgrenska, Östra and Mölndal) with either congestive heart failure (CHF) or acute coronary syndrome (ACS), only 302 patients who had undergone echocardiography with data on sPAP were included in the present study. In order to identify the lowest level of sPAP associated with increased mortality rate, Cox proportional-hazard regression multivariable models were built for sPAP levels as low as 30 mmHg and upward with 5 mmHg intervals.

RESULTS

sPAP >35 mmHg was identified as the lowest level associated with increased 5-year all-cause mortality (HR = 1.7, 95% of CI = 1.1-2.6 and p = .013). Every increase of 5 mmHg in sPAP was associated with a 10% increased relative risk for all-cause mortality.

CONCLUSIONS

In octogenarians with cardiac diseases the lowest level of sPAP associated with increased all-cause mortality was >35 mmHg and the mortality rate increased with increasing sPAP.

Native myocardial T1 mapping in pulmonary hypertension: correlations with cardiac function and hemodynamics

Objectives

To analyze alterations in left ventricular (LV) myocardial T1 times in patients with pulmonary hypertension (PH) and to investigate their associations with ventricular function, mass, geometry and hemodynamics.

Methods

Fifty-eight patients with suspected PH underwent right heart catheterization (RHC) and 3T cardiac magnetic resonance imaging. Ventricular function, geometry and mass were derived from cine real-time short-axis images. Myocardial T1 maps were acquired by a prototype modified Look-Locker inversion-recovery sequence in short-axis orientations. LV global, segmental and ventricular insertion point (VIP) T1 times were evaluated manually and corrected for blood T1.

Results

Septal, lateral, global and VIP T1 times were significantly higher in PH than in non-PH subjects (septal, 1249 ± 58 ms vs. 1186 ± 33 ms, p < 0.0001; lateral, 1190 ± 45 ms vs. 1150 ± 33 ms, p = 0.0003; global, 1220 ± 52 ms vs. 1171 ± 29 ms, p < 0.0001; VIP, 1298 ± 78 ms vs. 1193 ± 31 ms, p < 0.0001). In PH, LV eccentricity index was the strongest linear predictor of VIP T1 (r = 0.72). Septal, lateral and global T1 showed strong correlations with VIP T1 (r = 0.81, r = 0.59 and r = 0.75, respectively).

Conclusions

In patients with PH, T1 times in VIPs and in the entire LV myocardium are elevated. LV eccentricity strongly correlates with VIP T1 time, which in turn is strongly associated with T1 time changes in the entire LV myocardium.

Key Points

• Native T1 mapping detects left ventricular myocardial alterations in pulmonary hypertension

• In pulmonary hypertension, native T1 times at ventricular insertion points are increased

• These T1 times correlate strongly with left ventricular eccentricity

• In pulmonary hypertension, global and segmental myocardial T1 times are increased

• Global, segmental and ventricular insertion point T1 times are strongly correlated

Noninvasive identification of left-sided heart failure in a population suspected of pulmonary arterial hypertension

Exclusion of pulmonary hypertension secondary to left-sided heart disease (left heart failure (LHF)) is pivotal in the diagnosis of pulmonary arterial hypertension (PAH). In case of doubt, invasive measurements are recommended. The aim of the present study was to investigate whether it is possible to diagnose LHF using noninvasive parameters in a population suspected of PAH.300 PAH and 80 LHF patients attended our pulmonary hypertension clinic before August 2010, and were used to build the predictive model. 79 PAH and 55 LHF patients attended our clinic from August 2010, and were used for prospective validation.A medical history of left heart disease, S deflection in V1 plus R deflection in V6 in millimetres on ECG, and left atrial dilation or left valvular heart disease that is worse than mild on echocardiography were independent predictors of LHF. The derived risk score system showed good predictive characteristics: R(2)=0.66 and area under the curve 0.93. In patients with a risk score ≥72, there is 100% certainty that the cause of pulmonary hypertension is LHF. Using this risk score system, the number of right heart catheterisations in LHF may be reduced by 20%.In a population referred under suspicion of PAH, a predictive model incorporating medical history, ECG and echocardiography data can diagnose LHF noninvasively in a substantial percentage of cases.

Diagnosis of pulmonary arterial hypertension

Accurate diagnosis of pulmonary arterial hypertension can be challenging and often requires a high index of clinical suspicion. Use of a variety of noninvasive tests can help define the population of patients in whom invasive cardiac catheterization should be pursued. An understanding of the historical, physical exam, electrocardiographic, radiographic, and echocardiographic clues in the diagnosis is important. A ventilation-perfusion scan and careful assessment for left-to-right shunting are mandatory to avoid missing reasons for pulmonary hypertension that may require nonpharmacologic management. Right heart, and sometimes concomitant left heart, catheterization is required to establish the diagnosis and distinguish pulmonary arterial from pulmonary venous hypertension.

Pulmonary hypertension in elderly patients with diastolic dysfunction and preserved ejection fraction

Purpose:

Patients with diastolic dysfunction may have a disproportionate degree of elevation in pulmonary pressure, particularly in the elderly. Higher pulmonary vascular resistance in the elderly patients with heart failure but preserved ejection fraction suggests that beyond the post-capillary contribution of pulmonary venous congestion, a pre-capillary component of pulmonary arterial hypertension occurs. We aim to identify if pulmonary vascular resistance in elderly patients with diastolic dysfunction is disproportionately higher than patients with systolic dysfunction independent of filling pressures.

Methods:

389 patients identified retrospectively between 2003- 2010; elderly with preserved ejection fraction, elderly with depressed ejection fraction, and primary arterial hypertension who underwent right-heart catheterization at Rush University.

Results:

No significant difference in pulmonary vascular resistance between systolic and diastolic dysfunction. The mean difference in pulmonary vascular resistance was not statistically significant at 0.40 mmHg·min/l (95% CI -3.03 to 3.83) with similar left ventricular filling pressures with mean difference of 3.38 mmHg (95% CI, -1.27 to 8.02). When adjusted for filling pressures, there remained no difference in pulmonary vascular resistance for systolic and diastolic dysfunction. The mean pulmonary vascular resistance is more elevated in systolic heart failure compared to diastolic heart failure with means 3.13 mmHg·min/l and 3.52 mmHg·min/l, respectively.

Conclusion:

There was no other association identified for secondary pulmonary hypertension other than diastolic dysfunction and chronic venous pulmonary hypertension. Our results argue against any significant arterial remodeling that would lead to disproportionate pre-capillary hypertension, and implies that treatment should focus on lowering filling pressure rather than treating the pulmonary vascular tree.

Pulmonary hypertension with left-sided heart disease

Pulmonary hypertension (PH) with left-sided heart disease is defined, according to the latest Venice classification, as a Group 2 PH, which includes left-sided ventricular or atrial disease, and left-sided valvular diseases. These conditions are all associated with increased left ventricular filling pressure. Although PH with left-sided heart disease is a common entity, and long-term follow-up trials have provided firm recognition that development of left-sided PH carries a poor outcome, available data on incidence, pathophysiology, and therapy are sparse. Mitral stenosis was reported as the most frequent cause of PH several decades ago, but PH with left-sided heart disease is now usually caused by systemic hypertension and ischemic heart disease. In patients with these conditions, PH develops as a consequence of impaired left ventricular relaxation and distensibility. Chronic sustained elevation of cardiogenic blood pressure in pulmonary capillaries leads to a cascade of untoward retrograde anatomical and functional effects that represent specific targets for therapeutic intervention. The pathophysiological and clinical importance of the hemodynamic consequences of left-sided heart disease, starting with lung capillary injury and leading to right ventricular overload and failure, are discussed in this Review, focusing on PH as an evolving contributor to heart failure that may be amenable to novel interventions.

Prevalence and risk factors of pulmonary hypertension in patients with elevated pulmonary venous pressure and preserved ejection fraction

Pulmonary hypertension (PH) is a well-recognized complication of left-sided heart failure with preserved left ventricular systolic function that portends a worse prognosis. The identification of risk factors may provide insight into possible mechanisms for the development of PH in this population. Targeting these risk factors could possibly attenuate the development of PH. The limited data available regarding the prevalence of PH and its risk factors in patients with heart failure with preserved left ventricular systolic function are based on echocardiography. To further study this, an institutional database was searched for all patients who underwent right-sided and left-sided cardiac catheterization with ventriculography from October 1996 to September 2007 who met the following criteria: left ventricular end-diastolic pressure (LVEDP) >15 mm Hg, a left ventricular ejection fraction > or =50%, and no significant left-sided cardiac valvular disease. The demographic, clinical, and hemodynamic data of these patients were then analyzed. Of 455 patients who met these criteria, 239 (52.5%) had PH, defined as mean pulmonary artery pressure >25 mm Hg. Using multivariate logistic regression, PH was strongly and independently associated with LVEDP > or =25 mm Hg (odds ratio 4.3), morbid obesity (odds ratio 3.4), and atrial arrhythmias (odds ratio 3.1). Other significant associations were age > or =80 years, chronic obstructive pulmonary disease, and dyspnea on exertion. In conclusion, PH is a frequent finding in patients with elevated LVEDPs and preserved left ventricular systolic function. Factors associated with its development are LVEDP > or =25 mm Hg, morbid obesity, atrial arrhythmias, age > or =80 years, chronic obstructive pulmonary disease, and dyspnea on exertion.

Pulmonary hypertension in heart failure with preserved ejection fraction: a community-based study

OBJECTIVES

This study sought to define the prevalence, severity, and significance of pulmonary hypertension (PH) in heart failure with preserved ejection fraction (HFpEF) in the general community.

BACKGROUND

Although HFpEF is known to cause PH, its development is highly variable. Community-based data are lacking, and the relative contribution of pulmonary venous versus pulmonary arterial hypertension (HTN) to PH in HFpEF is unknown. We hypothesized that PH would be a marker of symptomatic pulmonary congestion, distinguishing HFpEF from pre-clinical hypertensive heart disease.

METHODS

This community-based study of 244 HFpEF patients (age 76 +/- 13 years; 45% male) was followed up using Doppler echocardiography over 3 years. Control subjects were 719 adults with HTN without HF (age 66 +/- 10 years; 44% male). Pulmonary artery systolic pressure (PASP) was derived from the tricuspid regurgitation velocity and PH defined as PASP >35 mm Hg. Pulmonary capillary wedge pressure (PCWP) was estimated from the ratio of early transmitral flow velocity to early mitral annular diastolic velocity.

RESULTS

In HFpEF, PH was present in 83% and the median (25th, 75th percentile) PASP was 48 (37, 56) mm Hg. PASP increased with PCWP (r = 0.21; p < 0.007). Adjusting for PCWP, PASP was higher in HFpEF than HTN (p < 0.001). The PASP distinguished HFpEF from HTN with an area under the receiver-operating characteristic curve of 0.91 (p < 0.001) and strongly predicted mortality in HFpEF (hazard ratio: 1.3 per 10 mm Hg; p < 0.001).

CONCLUSIONS

PH is highly prevalent and often severe in HFpEF. Although pulmonary venous HTN contributes to PH, it does not fully account for the severity of PH in HFpEF, suggesting that a component of pulmonary arterial HTN also contributes. The potent effect of PASP on mortality lends support for therapies aimed at pulmonary arterial HTN in HFpEF.

The cancer paradigm of severe pulmonary arterial hypertension

The plexiform lesions of severe pulmonary arterial hypertension (PAH) are similar in histologic appearance, whether the disease is idiopathic or secondary. Both forms of the disease show actively proliferating endothelial cells without evidence of apoptosis. Here, we discuss the pathobiology of the atypical, angioproliferative endothelial cells in severe PAH. The concept of the endothelial cell as a "quasi-malignant" cell provides a new framework for antiproliferative, antiangiogenic therapy in severe PAH.

Cardiovascular consequences of pulmonary hypertension

Pulmonary hypertension occurs when pulmonary vascular pressures are elevated. Pulmonary arterial hypertension is associated with occlusion of the pulmonary arterial tree, while pulmonary venous hypertension is seen when pulmonary vein outflow is impeded. Cardiovascular consequences are common with pulmonary hypertension, regardless of the underlying pathogenesis and whether management is complex. However, there are a number of interventions that may improve quality of life and survival of pulmonary hypertension. This article discusses current recommendations for diagnosis and management.

Pulmonary hypertension in older adults

Pulmonary hypertension is a frequently encountered problem in older patients. True idiopathic pulmonary arterial hypertension can also be seen and requires careful exclusion in older patients. Institution of therapies must be tempered with an appreciation of individual comorbidities and functional limitations that may affect patients' ability to comply and benefit from the complex treatments available for pulmonary arterial hypertension. This article reviews the existing data on the various forms of pulmonary hypertension presenting in older patients and on appropriate therapy in this challenging population.

Diagnosis of pulmonary arterial hypertension

Accurate diagnosis of pulmonary arterial hypertension is a challenging and complex process that requires a high index of clinical suspicion from even the most astute clinician. This article discusses the use of a variety of noninvasive tests that can help define the population of patients in whom invasive cardiac catheterization should be pursued. It points out the vagaries and limitations of electrocardiography and the radiographic and echocardiographic clues to the diagnosis. Ultimately, right- and, often, concomitant left-heart catheterization is required to establish the diagnosis and distinguish pulmonary arterial hypertension from pulmonary venous hypertension.