Citations

Background— People with heart failure and preserved ejection fraction develop increases in left ventricular (LV) end-diastolic pressures during exercise that contribute to dyspnea. In normal open-chest animal preparations, the pericardium restrains LV filling when central blood volume increases. We hypothesized that resection of the pericardium using a minimally invasive epicardial approach would mitigate the increase in LV end-diastolic pressure that develops during volume loading in normal and diseased hearts with the chest intact. Methods and Results— Invasive hemodynamic assessment was performed at baseline and after saline load before and after pericardial resection in normal canines with open (n=3) and closed chest (n=5) and in a pig model with features of human heart failure and preserved ejection fraction with sternum intact (n=4). In closed-chest animals, pericardiotomy was performed using a novel subxiphoid procedure. In both experimental preparations of normal dogs, pericardiotomy blunted the increase in LV end-diastolic pressure with saline infusion, while enhancing the saline-mediated increase in LV end-diastolic volume. With chest intact in the pig model, percutaneous pericardial resection again blunted the increase in LV end-diastolic pressure secondary to volume expansion (+4±3 versus +13±5 mm Hg; P =0.014), while enhancing the saline-mediated increase in LV end-diastolic volume (+17±1 versus +10±2 mL; P =0.016). Conclusions— This proof of concept study demonstrates that pericardial resection through a minimally invasive percutaneous approach mitigates the elevation in LV filling pressures with volume loading in both normal animals and a pig model with diastolic dysfunction. Further study is warranted to determine whether this method is safe and produces similar acute and chronic hemodynamic benefits in people with heart failure and preserved ejection fraction.

Background: Heart failure (HF) with preserved ejection fraction (HFpEF) is a heterogeneous syndrome. Phenotyping patients into pathophysiologically homogeneous groups may enable better targeting of treatment. Obesity is common in HFpEF and has many cardiovascular effects, suggesting that it may be a viable candidate for phenotyping. We compared cardiovascular structure, function, and reserve capacity in subjects with obese HFpEF, those with nonobese HFpEF, and control subjects. Methods: Subjects with obese HFpEF (body mass index ≥35 kg/m 2 ; n=99), nonobese HFpEF (body mass index <30 kg/m 2 ; n=96), and nonobese control subjects free of HF (n=71) underwent detailed clinical assessment, echocardiography, and invasive hemodynamic exercise testing. Results: Compared with both subjects with nonobese HFpEF and control subjects, subjects with obese HFpEF displayed increased plasma volume (3907 mL [3563–4333 mL] versus 2772 mL [2555–3133 mL], and 2680 mL [2380–3006 mL]; P <0.0001), more concentric left ventricular remodeling, greater right ventricular dilatation (base, 34±7 versus 31±6 and 30±6 mm, P =0.0005; length, 66±7 versus 61±7 and 61±7 mm, P <0.0001), more right ventricular dysfunction, increased epicardial fat thickness (10±2 versus 7±2 and 6±2 mm; P <0.0001), and greater total epicardial heart volume (945 mL [831–1105 mL] versus 797 mL [643–979 mL] and 632 mL [517–768 mL]; P <0.0001), despite lower N-terminal pro-B-type natriuretic peptide levels. Pulmonary capillary wedge pressure was correlated with body mass and plasma volume in obese HFpEF ( r =0.22 and 0.27, both P <0.05) but not in nonobese HFpEF ( P ≥0.3). The increase in heart volumes in obese HFpEF was associated with greater pericardial restraint and heightened ventricular interdependence, reflected by increased ratio of right- to left-sided heart filling pressures (0.64±0.17 versus 0.56±0.19 and 0.53±0.20; P =0.0004), higher pulmonary venous pressure relative to left ventricular transmural pressure, and greater left ventricular eccentricity index (1.10±0.19 versus 0.99±0.06 and 0.97±0.12; P <0.0001). Interdependence was enhanced as pulmonary artery pressure load increased ( P for interaction <0.05). Compared with those with nonobese HFpEF and control subjects, obese patients with HFpEF displayed worse exercise capacity (peak oxygen consumption, 7.7±2.3 versus 10.0±3.4 and12.9±4.0 mL/min·kg; P <0.0001), higher biventricular filling pressures with exercise, and depressed pulmonary artery vasodilator reserve. Conclusions: Obesity-related HFpEF is a genuine form of cardiac failure and a clinically relevant phenotype that may require specific treatments.

Background Soluble ST2 is a biomarker that is elevated in certain systemic inflammatory diseases. Comorbidity‐driven microvascular inflammation is postulated to play a key role in heart failure with preserved ejection fraction ( HF p EF ) pathophysiology, but data on how sST 2 relates to clinical characteristics or inflammatory conditions or biomarkers in HF p EF are limited. We sought to determine circulating levels and clinical correlates of sST 2 in HF pEF. Methods and Results At enrollment, patients (n=174) from the Phosphodiesterase‐5 Inhibition to Improve Clinical Status And Exercise Capacity in Diastolic Heart Failure (RELAX) trial of sildenafil in HF p EF had sST 2 levels measured. Clinical characteristics; cardiac structure and function; exercise performance; and biomarkers of neurohumoral activation, systemic inflammation and fibrosis, and myocardial necrosis were assessed in relation to sST 2 levels. Median sST 2 levels in male and female HFpEF patients were 36.7 ng/mL (range 30.9–49.2 ng/mL; reference range 4–31 ng/mL) and 30.8 ng/mL (range 25.3–39.3 ng/mL; reference range 2–21 ng/mL), respectively. Among HF p EF patients, higher sST 2 levels were associated with the presence of diabetes mellitus; atrial fibrillation; renal dysfunction; right ventricular pressure overload and dysfunction; systemic congestion; exercise intolerance; and biomarkers of systemic inflammation and fibrosis, neurohumoral activation, and myocardial necrosis ( P <0.05 for all). sST 2 was not associated with left ventricular structure or left ventricular systolic or diastolic function. Conclusions In HF p EF , sST 2 levels were associated with proinflammatory comorbidities, right ventricular pressure overload and dysfunction, and systemic congestion but not with left ventricular geometry or function. These data suggest that sST2 may be a marker of systemic inflammation in HF p EF and potentially of extracardiac origin. Clinical Trial Registration URL : http://www.clinicaltrials.gov . Unique identifier: NCT 00763867.

Background— Afterload reduction is a cornerstone in the management of patients with heart failure (HF) and reduced ejection fraction. However, arterial load and the effect of HF therapies on afterload might vary between individuals. Tailoring vasoactive medicines to patients with HF based upon better understanding of arterial afterload may enable better individualization of therapy. Methods and Results— Subjects with HF and reduced ejection fraction underwent aggressive titration of vasoactive HF therapies with assessment of central aortic waveforms analyzed using pulse wave, wave separation, and arterial reservoir models. Clinical response to treatment was assessed using the 6-minute walk test distance, which increased in 25 subjects and decreased or remained unchanged in 13. Subjects with improvement on therapy displayed higher aortic pressure wave pulsatility (central pulse pressure [PP], reflected pressure wave, and reservoir pressure) at study entry compared with subjects without improvement (all P <0.05). Parameters derived by the arterial analysis methods were strongly correlated with one another and displayed similar ability to predict improvement. Aortic pressure pulsatility significantly decreased in subjects with functional improvement, whereas no change was observed in patients without functional improvement ( P for interaction <0.05). These differences in arterial load at baseline and on therapy were not apparent from conventional brachial artery cuff pressure assessments. Conclusions— Increased aortic pressure wave pulsatility and greater decrease in pulsatility on treatment are associated with functional improvement in patients with HF and reduced ejection fraction receiving aggressive vasodilator titration. These differences are not identifiable using brachial cuff pressures. Central aortic waveform analysis may enable better individualization of vasoactive therapies in chronic HF and reduced ejection fraction. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00588692.

Abstract Aims Short-term studies have reported left ventricular (LV) dilatation following surgical creation of arteriovenous fistulas (AVF) or arteriovenous grafts (AVGs), but chronic cardiac structural and functional changes have not been examined or related to clinical outcomes following AVF/AVG. We sought to characterize the long-term changes in cardiac structure and function in patients undergoing shunt creation for haemodialysis. Methods and results A retrospective analysis was performed of patients undergoing echocardiography before and after surgical AVF/AVG creation for the initiation of haemodialysis. 137 patients underwent echocardiographic examinations prior to AVF and 2.6 years (median) after AVF creation. Following AVF and dialysis initiation, there were reductions in blood pressure, body weight and estimated plasma volume coupled with modest reverse LV remodelling. In contrast, AVF/AVG creation was associated with significant right ventricular (RV) dilatation and deterioration in RV function. Incident heart failure (HF) developed in 43% of patients in tandem with greater RV remodeling. The development of RV dilation following surgical AVF/AVG was independently associated with increased risk of death [HR 3.9, 95% CI (1.7–9.2), P = 0.001]. Conclusion In long-term follow-up, RV remodelling and dysfunction develop following AVF/AVG creation and dialysis initiation, despite improved control of LV pressure load through dialysis. Deleterious effects on right heart structure and function are coupled with development of incident HF and increased risk of death. Further study is required to identify patients at greatest risk for detrimental AVF/AVG changes who may benefit from alternate forms of dialysis or potentially ligation of existing AVF.

Background: Diagnosis of heart failure with preserved ejection fraction (HFpEF) is challenging and relies largely on demonstration of elevated cardiac filling pressures (pulmonary capillary wedge pressure). Current guidelines recommend use of natriuretic peptides (N-terminal pro-B type natriuretic peptide) and rest/exercise echocardiography (E/e′ ratio) to make this determination. Data to support this practice are conflicting. Methods: Simultaneous echocardiographic-catheterization studies were prospectively conducted at rest and during exercise in subjects with invasively proven HFpEF (n=50) and participants with dyspnea but no identifiable cardiac pathology (n=24). Results: N-Terminal pro-B type natriuretic peptide levels were below the level considered to exclude disease (≤125 pg/mL) in 18% of subjects with HFpEF. E/e′ ratio was correlated with directly measured pulmonary capillary wedge pressure at rest ( r =0.63, P <0.0001) and during exercise ( r =0.57, P <0.0001). Although specific, current guidelines were poorly sensitive, identifying only 34% to 60% of subjects with invasively proven HFpEF on the basis of resting echocardiographic data alone. Addition of exercise echocardiographic data (E/e′ ratio>14) improved sensitivity (to 90%) and thus negative predictive value, but decreased specificity (71%). Conclusions: Currently proposed HFpEF diagnostic guidelines on the basis of resting data are poorly sensitive. Adding exercise E/e′ data improves sensitivity and negative predictive value but compromises specificity, suggesting that exercise echocardiography may help rule out HFpEF. These results question the accuracy of current approaches to exclude HFpEF on the basis of resting data alone and reinforce the value of exercise testing using invasive and noninvasive hemodynamic assessments to definitively confirm or refute the diagnosis of HFpEF. Clinical Trial Registration: URL: http://www.clinicaltrials.gov . Unique Identifier: NCT01418248.

Using the reservoir-wave approach (RWA) we previously characterized pulmonary vasculature mechanics in a normal canine model. We found reflected backward-traveling waves that decrease pressure and increase flow in the proximal pulmonary artery (PA). These waves decrease right ventricular (RV) afterload and facilitate RV ejection. With pathological alterations to the pulmonary vasculature, these waves may change and impact RV performance. Our objective in this study was to characterize PA wave reflection and the alterations in RV performance in cardiac patients, using the RWA. PA pressure, Doppler-flow velocity, and pulmonary arterial wedge pressure were measured in 11 patients with exertional dyspnea. The RWA was employed to analyze PA pressure and flow; wave intensity analysis characterized PA waves. Wave-related pressure was partitioned into two components: pressures due to forward-traveling and to backward-traveling waves. RV performance was assessed by examining the work done in raising reservoir pressure and that associated with the wave components of systolic PA pressure. Wave-related work, the mostly nonrecoverable energy expended by the RV to eject blood, tended to vary directly with mean PA pressure. Where PA pressures were lower, there were pressure-decreasing/flow-increasing backward waves that aided RV ejection. Where PA pressures were higher, there were pressure-increasing/flow-decreasing backward waves that impeded RV ejection. Pressure-increasing/flow-decreasing backward waves were responsible for systolic notches in the Doppler flow velocity profiles in patients with the highest PA pressure. Pulmonary hypertension is characterized by reflected waves that impede RV ejection and an increase in wave-related work. The RWA may facilitate the development of therapeutic strategies.

Percutaneous Pericardiotomy ToolIntroductionEpicardial procedures frequently require pericardial manipulation. We aimed to develop a nonsurgical percutaneous pericardial modification tool that may (1) facilitate epicardial‐based procedures by enabling adhesiolysis or (2) attenuate the myocardial constraining effect of the pericardium.MethodsThree novel devices were developed to enable pericardiotomy, all of which can be deployed in over‐the‐wire fashion following percutaneous epicardial access. The grasper permits us to seize the pericardial membrane providing leverage for incision. The scissors enables anterograde cutting maneuvers. The reverse‐slitter allows retrograde incisions; in addition, this device has a deflectable tip that increases the potential cutting area. We optimized these tools for safety by including electrodes to test for phrenic nerve stimulation as well as myocardial stimulation to determine directionality of the cutting devices. The base of the scissors and reverse‐slitter are also blunt ensuring that the cutting element is always away from the myocardium.ResultsFollowing 5 nonbeating heart bench test experiments for prototype development, 11 animal (9 canine, 2 swine) studies were performed. Of these 2 were proof‐of‐concept open chest studies; the remaining 9 were entirely closed‐chest, percutaneous procedures allowing for remodification of the prototypes. The tools successfully permitted incision of the pericardium in all studies. Hemodynamic measurements were assessed postincision and showed no compromise of systolic function. No coronary artery or phrenic nerve damage was seen in any study.ConclusionPercutaneous pericardiotomy is feasible and appears to be safe. It may provide leverage in epicardial‐based procedures and offer treatment options in disease processes characterized by pericardial restraint.