Fayyaz, Ahmed

Abstract Background Left atrial pressure (LAP) is clinically estimated by the occluded pulmonary artery (PA) pressure (PA wedge pressure, PAWP), which should equalize with downstream LAP. Early studies reported the potential for PAWP to exceed LAP, but the frequency and clinical significance of this finding is unclear. Purpose This study aimed to investigate the hemodynamic characteristics, physiologic determinants, and prognostic impact of patients with PAWP exceeding LAP. Method Patients who underwent right heart catheterization (RHC) for diagnosis or treatment with PAWP and simultaneous measurement of LAP were identified. Patients were divided into two groups based on differences in PAWP and LAP. Pulmonary capillary pressure (Pc) was measured using the PA occlusion technique. Pulmonary vascular resistance (PVR) was then partitioned into upstream PVRa ([mean PA pressure (PAP)-Pc]/cardiac output [CO]) and downstream PVRv ([Pc-PAWP]/CO), with each expressed as a percentage of PVR. Results 675 patients underwent RHC with transseptal puncture allowing measurement of both PAWP and LAP simultaneously. A strong correlation and agreement between PAWP and LAP were demonstrated (r=0.92, P<0.001; bias +0.5 mmHg), but 310 patients (46%) displayed PAWP exceeding LAP by at least 1 mmHg (mean difference 3±2 mmHg). Patients with PAWP exceeding LAP displayed higher mean PAP (Figure 1A) and PVR calculated using LAP as the downstream pressure (PVR-LA: 2.10 [1.13-3.53] vs 3.38 [2.19-5.66] WU, P<0.001). PAWP was significantly higher in patients with PAWP exceeding LAP, although there was no significant difference in LAP between the groups (Figure 1B-C). PA compliance, which does not rely on either PAWP or LAP for calculation, was significantly lower in patients with PAWP exceeding LAP (2.7 [1.8-4.0] vs 2.1 [1.5-3.0] mL/mmHg, P<0.001, Figure 1D). The difference between PAWP and LAP was significantly correlated with mean PAP (r=0.32, P<0.001, Figure 1E). In 63 patients where Pc could be measured, those with PAWP exceeding LAP showed a higher Pc and greater pulmonary venous (vs arterial) distribution of PVR (Figure 1F-H). Over 5.4 (IQR 1.7-10.2) years, the composite outcome of all-cause death or heart failure hospitalization occurred in 326 patients (48%). Patients with PAWP exceeding LAP had a higher risk of the composite outcome than those without (log-rank P<0.001, Figure 2). Patients with PAWP exceeding LAP had 37% greater risk of composite outcome than those without (hazard ratio 1.37, 95% CI 1.09-1.73; P=0.008) after adjusting for age, sex, hemoglobin, moderate or greater mitral regurgitation, and tricuspid regurgitation, LAP, and mean PAP. Conclusions While PAWP is a robust surrogate for LAP, the former commonly exceeds the latter, and patients with PAWP exceeding LAP have more severe pulmonary vascular disease, greater capillary hypertension and venous involvement, and a higher risk for adverse outcomes.

Abstract Background In patients with heart failure with preserved ejection fraction (HFpEF), studies have described different HFpEF phenogroups based on medical comorbidities and variable echocardiographic, invasive hemodynamic, and biomarker data. We hypothesized that myocardial histopathologic findings may define phenogroups with differing clinical features and outcomes in patients with HFpEF. Methods We analyzed consecutive patients with left HF and EF ≥50% who underwent right ventricular septal endomyocardial biopsy (EMB) at our institution between 2001 and 2022 to investigate HF etiology. Patients with infiltrative or hypertrophic cardiomyopathy, sarcoidosis, myocarditis, primary valvular heart disease, constrictive pericarditis, isolated right HF, or insufficient EMB samples were excluded. Clinical, echocardiographic, and invasive hemodynamic data were collected. The severity of hypertrophy and fibrosis on EMB specimens was characterized (semiquantitative grading) by experienced cardiac pathologists based on standard histologic stains. Patients were stratified into four phenogroups based on EMB findings: "mild" (none/mild hypertrophy and fibrosis), "hypertrophy" (moderate/marked hypertrophy, minimal/mild fibrosis), "fibrosis" (moderate/marked fibrosis, none/mild hypertrophy), and "severe" (moderate/marked hypertrophy and fibrosis). Results Among the 121 patients analyzed, the median age was 67 years, 50% were female and cardiovascular conditions were common (Table 1). Fibrosis was graded as minimal in 21% (n=25), mild in 64% (n=77), moderate in 12% (n=15), and marked in 3% (n=4). Hypertrophy was graded as none in 4% (n=5), mild in 41% (n=50), moderate in 40% (n=48), and marked in 15% (n=18). Only one patient had the isolated "fibrosis" phenogroup and was excluded from further analysis, while 54 had the "mild", 48 had the "hypertrophy", and 18 had the "severe" phenogroup (Table 1). The "hypertrophy" phenogroup exhibited significantly higher rates of hypertension, diabetes, RV dilation, and higher pulmonary artery pressures. Over a median follow-up of 7.9 years (3.1–13.8), mortality rate varied according to the histopathologic phenogroups (Figure 1, p=0.034) with "severe" having the worst and "mild" having the best outcomes. Survival analyses based on fibrosis grades alone, hypertrophy grades alone, or echocardiographic hypertrophy did not reveal significant differences (all p = NS). Differences in survival remained significant adjusting for age (HR 3.39, 95% CI 1.20-9.58). Conclusions The integrated severity of histopathologic hypertrophic and fibrotic remodeling defined HFpEF phenogroups with variable prognosis. Clinical features did not reliably identify histopathologic phenogroups. These data suggest that advanced myocardial phenotyping (e.g., gene, protein, metabolism) may reveal unique HFpEF myocardial subtypes in need of specific therapies.Figure 1

Background: Pulmonary vascular resistance (PVR) is commonly considered to reflect opposition to lung blood flow caused by the arteries (PVRa), but downstream venous resistance (PVRv) may also contribute to pulmonary hypertension (PH) associated with left heart diseases (PH-LHD). In patients referred for right heart catheterization, we investigated PVR distribution and its pathophysiologic implications in PH-LHD and other forms of PH. Methods: Patients with PH-LHD (n=292), pulmonary veno-occlusive disease (PVOD, n=10), chronic thromboembolic PH (CTEPH, n=36) and controls without PH (Ctrl, n=28) were included. Pulmonary capillary pressure (Pc) was calculated using the pulmonary artery occlusion technique. PVR was partitioned into PVRa ((mPAP-Pc)/CO) and PVRv ((Pc-PAWP)/CO) with each expressed as % of PVR. PH-LHD was divided into isolated post-capillary PH (IpcPH) and combined post- and pre-capillary PH (CpcPH). Further, PH-LHD was categorized as heart failure with preserved (HFpEF, EF≥50%) or reduced (HFrEF, EF<50%) ejection fraction or left valvular heart disease (L-VHD). In subsets, functional tests (n=71-81) and histological pulmonary venous (PV) remodeling (autopsy, n=15) were performed to investigate correlations with PVR distribution. Results: PVR distribution showed an arterial predominance in Ctrl and CTEPH, and increasing venous contribution in PH-LHD (both IpcPH and CpcPH) and PVOD (Figure A-F). In PH-LHD, patients with HFpEF had proportionately greater venous contribution to PVR than HFrEF and L-VHD (Figure G-I), though not to the extent observed in PVOD. In subsets, PVRv was more strongly correlated with E/e’, extravascular lung water estimated by sonographic B-lines, arterial PO 2 , pulmonary dead space fraction (VD/VT), DLCO, and, among the autopsy series, PV intimal thickness as compared to PVRa (Figure J-O). Conclusions: Pulmonary venous contributions to PVR are amplified in patients with PH-LHD, which is correlated with greater lung congestion, ventilatory and gas exchange abnormalities, and histological venous remodeling. Further study is required to determine the molecular mechanism and novel therapeutics of pulmonary venous disease in PH-LHD.

Background: Dysfunction of systemic vascular endothelial cells (ECs) is common in heart failure with preserved ejection fraction (HFpEF). We sought to determine if organ-specific EC translational heterogeneity is present in HFpEF. Using a transgenic mouse model (RiboTag EC ), we analyzed the translatome (the mRNAs bound with ribosomes) of organ-specific ECs in a mouse HFpEF model induced by hypertensive/metabolic stresses. Methods: Six-month-old male RiboTag EC ( Cdh5 CreERT2+ / Rpl22 HA/+ ) mice, expressing a hemagglutinin tag in EC ribosomal protein Rpl22, were fed a high-fat diet and L-NAME water (N=4) or a normal diet and water (N=5) for 7 weeks. Organs were collected for Translating Ribosome Affinity Purification, RNA isolation, and RNA-seq. RNA-seq data were visualized using uniform manifold approximation and projection (UMAP). Differentially expressed genes (DEGs; absolute fold change ≥ 2 and false discovery rate (FDR) adjusted p-value ≤ 0.05). Pathway enrichment analyses were conducted (Ingenuity Pathways Analysis (IPA)). Results: In UMAP, the EC translatome clustered by organ (heart, lung, skeletal muscle, and liver) highlighting organ-specific EC heterogeneity and by disease (HFpEF) status with cardiac ECs showing the most dramatic changes with HFpEF (Fig A). Cardiac ECs in HFpEF (vs Control) had 283 downregulated and 23 upregulated DEG (Fig B) out of 14,923 genes identified. There were significant differences in 142 canonical pathways (16 upregulated, 126 downregulated), including LXR/RXR activation, DHCR 24 signaling, regulation of insulin-like growth factors, eNOS signaling, acute phrase response (all down regulated) and IL-1b-mediated inhibition of RXR and unfolded protein response (both up regulated) (Fig C). Conclusion: HFpEF induction caused extensive translational changes in EC but particularly cardiac ECs. In cardiac ECs, metabolism, anti-inflammatory, vasodilation, tissue repair, and angiogenesis pathways were inhibited, while pro-inflammatory response, insulin resistance, and proteostasis pathways were activated.

Background and Objective: Decline of cardiovascular (CV) function is commonly observed in patients with severe acute pancreatitis (AP), which is associated with high mortality and morbidity. While the pathological changes in the pancreas during severe AP have been extensively studied, the impact on the CV system has not been well characterized. Furthermore, obesity is a major risk factor for severe AP. Hereby we utilized an obesity-associated mouse AP model to assess potential alterations in vascular integrity and cardiac function, two major components of circulatory failure. Methods: Wild-type male C57BL6J mice were fed a normal or a high fat (to induce obesity) diet. Both groups received intraperitoneal injection of cerulein (100 mg/kg/h x12) to induce AP. H&E and TUNEL staining of pancreas were performed to assess histology and cell death. To measure vascular integrity, we measured the leakiness of a fluorescein-conjugated dextran (70 kDa) in tissue parenchyma and serum levels of soluble vascular endothelial (VE)-cadherin, which has recently shown to be shed from endothelial cells with disrupted adherens junctions. Cardiac systolic and diastolic function were assessed by echocardiography at baseline and post-AP induction. Results: Compared to lean mice, obese mice developed more severe pancreatic edema, cell death and inflammatory cell infiltration, along with significantly increased accumulation of fluorescent dextran in multiple organs including pancreas, heart, lung, and kidney, suggesting systemic disruption of vascular integrity. Increased serum levels of soluble VE-cadherin in obese mice (vs. lean) after AP induction further supported compromised endothelial cell barrier function. At baseline, obese mice exhibited similar cardiac function to lean mice. However, obese mice, but not lean mice, developed impaired systolic and diastolic function post-AP induction, as supported by decreased ejection fraction and e’ velocity respectively. Conclusion: In this obesity-associated severe AP mouse model, systemic vascular permeability is increased, and cardiac function is substantially compromised. Systemic vascular hyperpermeability and cardiac dysfunction may represent therapeutic targets to enhance the outcomes in severe AP.

Heart failure with preserved ejection fraction (HFpEF), characterized by cardiac diastolic dysfunction, leads to premature mortality with limited effective treatments. A recent study in HFpEF patients suggested neuropilin 1 (NRP1), an endothelial cell (EC) originated prognostic marker, might contribute to the pathogenesis of HFpEF. However, the functional role of NRP1 in the pathogenesis of HFpEF remains unclear. Purpose: To determine the functional role of NRP1 in the pathogenesis of HFpEF. Hypothesis: NRP-1 contributes to the pathogenesis of HFpEF, potentially mediated through chronic inflammation. Methods: HFpEF was induced by hypertensive and metabolic stresses in control (n=14) and tamoxifen-induced, endothelial cell-specific NRP1 knockout (NRP1 iEC-KO ) mice (n=13). We assessed cardiac diastolic function via echocardiography and pressure-volume loop through invasive catheters. To determine the inflammation level, we tested leukocyte adhesion, inflammatory marker vascular cell adhesion molecule 1 (VCAM-1), and intercellular adhesion molecule 1 (ICAM-1) mRNA level in control and NRP1 shRNA knockdown (NRP1 KD) human umbilical vein endothelial cells (HUVECs) with a stimulation of TNF-α. Student t-test (two tailed) was used and the criterion level of significance was set at p<0.05. Results: We found a significantly improved diastolic function in NRP1 iEC-KO mice, evidenced by a significantly reduced end diastolic pressure in NRP1 iEC-KO mice (8±2mmHg; n=7) compared to the controls (17±2mmHg; n=9; p=0.01) after HFpEF induction. E/A ratio was also significantly lower in NRP1 iEC-KO mice (2.0±0.2; n=10) compared to controls (2.7±0.3; n=12; p=0.04). Moreover, the isovolumic relaxation time was also significantly reduced in NRP1 iEC-KO mice (18±0.8ms; n=13) compared to controls (20±0.8ms; n=14; p=0.03). In addition, In HUVECs, NRP1 KD significantly reduced inflammatory marker VCAM-1 mRNA expression (95±16; n=5) compared to controls (293±36; n=5; p<0.01) upon TNF-α treatment. Similarly, NRP1 KD significantly reduced ICAM-1 mRNA expression (44±14; n=5) compared to controls (83±9; n=5; p=0.03) upon TNF-α treatment. Furthermore, leukocyte adhesion was significantly lower in the NRP1 KD group (57.0 ±8.6 cells/field) compared to the control group (90.8 ±9.1 cells/field; p=0.04). Conclusion: Endothelial NRP1 contributes to cardiac diastolic dysfunction and the pathogenesis of HFpEF, potentially mediated through the activation of chronic low-grade inflammation.

Abstract Aims In heart failure (HF), pulmonary venous hypertension (PVH) produces pulmonary hypertension (PH) with remodeling of pulmonary veins (PV) and arteries (PA). In a porcine PVH model, we performed proteomic-based bioinformatics to investigate unique pathophysiologic mechanisms mediating PA and PV remodeling. Methods and results Large PV were banded (PVH, n = 10) or not (Sham, n = 9) in piglets. At sacrifice, PV and PA were perfusion labelled for vessel-specific histology and proteomics. The PA and PV were separately sampled with laser-capture micro-dissection for mass spectrometry. Pulmonary vascular resistance [Wood Units; 8.6 (95% confidence interval: 6.3, 12.3) vs. 2.0 (1.7, 2.3)] and PA [19.9 (standard error of mean, 1.1) vs. 10.3 (1.1)] and PV [14.2 (1.2) vs. 7.6 (1.1)] wall thickness/external diameter (%) were increased in PVH (P &lt; 0.05 for all). Similar numbers of proteins were identified in PA (2093) and PV (2085) with 94% overlap, but biological processes differed. There were more differentially expressed proteins (287 vs. 161), altered canonical pathways (17 vs. 3), and predicted upstream regulators (PUSR; 22 vs. 6) in PV than PA. In PA and PV, bioinformatics indicated activation of the integrated stress response and mammalian target of rapamycin signalling with dysregulated growth. In PV, there was also activation of Rho/Rho-kinase signalling with decreased actin cytoskeletal signalling and altered tight and adherens junctions, ephrin B, and caveolae-mediated endocytosis signalling; all indicating disrupted endothelial barrier function. Indeed, protein biomarkers and the top PUSR in PV (transforming growth factor-beta) suggested endothelial to mesenchymal transition in PV. Findings were similar in human autopsy specimens. Conclusion These findings provide new therapeutic targets to oppose pulmonary vascular remodeling in HF-related PH.