Long-term reduction in morning and nighttime blood pressure after renal denervation: 36-month results from SPYRAL HTN-ON MED trial.

Elevated morning and nighttime blood pressures (BP) are associated with increased risk of cardiovascular events such as stroke and myocardial infarction. We compared the long-term changes in morning and nighttime BP in patients with uncontrolled hypertension (office systolic BP between 150 and <180 mmHg/diastolic BP ≥ 90 mmHg; mean ambulatory systolic BP (SBP) between 140 and <170 mmHg; 1-3 prescribed antihypertensive medications). Eighty patients were randomized to RDN or sham control. In patients taking at least 3 antihypertensive medications at 36 months (N = 23 RDN group; N = 23 sham group), the 24 h ambulatory SBP as well as morning (7:00-9:00AM) and nighttime (1:00-6:00AM) ambulatory SBP were significantly lower for the RDN group compared to sham control (24 h SBP: -20.2 vs. -10.2, p = 0.0087; morning SBP: -23.9 vs. -8.0 mmHg, p = 0.029; nighttime SBP: -20.8 vs. -7.2 mmHg, p = 0.0011). At 36 months, 24 h SBP was controlled to <130 mmHg in 40% of RDN patients in the morning compared to 6% for the sham group; P = 0.021 and in 80% of the RDN patients at night compared to 39% in the sham group; P = 0.019. Major adverse events through 36 months were rare in both groups, and there were no renal artery re-interventions or vascular complications. Morning and nighttime SBP were significantly lower in patients prescribed at least 3 antihypertensive medications at 36 months in the SPYRAL HTN-ON MED trial for RDN compared with sham control. The results suggest RDN has significant benefit when the risk of cardiovascular events is highest

Axial stent strut angle influences wall shear stress after stent implantation: analysis using 3D computational fluid dynamics models of stent foreshortening

INTRODUCTION: The success of vascular stents in the restoration of blood flow is limited by restenosis. Recent data generated from computational fluid dynamics (CFD) models suggest that the vascular geometry created by an implanted stent causes local alterations in wall shear stress (WSS) that are associated with neointimal hyperplasia (NH). Foreshortening is a potential limitation of stent design that may affect stent performance and the rate of restenosis. The angle created between axially aligned stent struts and the principal direction of blood flow varies with the degree to which the stent foreshortens after implantation. METHODS: In the current investigation, we tested the hypothesis that stent foreshortening adversely influences the distribution of WSS and WSS gradients using time-dependent 3D CFD simulations of normal arteries based on canine coronary artery measurements of diameter and blood flow. WSS and WSS gradients were calculated using conventional techniques in ideal (16 mm) and progressively foreshortened (14 and 12 mm) stented computational vessels. RESULTS: Stent foreshortening increased the intrastrut area of the luminal surface exposed to low WSS and elevated spatial WSS gradients. Progressive degrees of stent foreshortening were also associated with strut misalignment relative to the direction of blood flow as indicated by analysis of near-wall velocity vectors. CONCLUSION: The current results suggest that foreshortening may predispose the stented vessel to a higher risk of neointimal hyperplasia

Alterations in regional vascular geometry produced by theoretical stent implantation influence distributions of wall shear stress: analysis of a curved coronary artery using 3D computational fluid dynamics modeling

BACKGROUND: The success of stent implantation in the restoration of blood flow through areas of vascular narrowing is limited by restenosis. Several recent studies have suggested that the local geometric environment created by a deployed stent may influence regional blood flow characteristics and alter distributions of wall shear stress (WSS) after implantation, thereby rendering specific areas of the vessel wall more susceptible to neointimal hyperplasia and restenosis. Stents are most frequently implanted in curved vessels such as the coronary arteries, but most computational studies examining blood flow patterns through stented vessels conducted to date use linear, cylindrical geometric models. It appears highly probable that restenosis occurring after stent implantation in curved arteries also occurs as a consequence of changes in fluid dynamics that are established immediately after stent implantation. METHODS: In the current investigation, we tested the hypothesis that acute changes in stent-induced regional geometry influence distributions of WSS using 3D coronary artery CFD models implanted with stents that either conformed to or caused straightening of the primary curvature of the left anterior descending coronary artery. WSS obtained at several intervals during the cardiac cycle, time averaged WSS, and WSS gradients were calculated using conventional techniques. RESULTS: Implantation of a stent that causes straightening, rather than conforms to the natural curvature of the artery causes a reduction in the radius of curvature and subsequent increase in the Dean number within the stented region. This straightening leads to modest skewing of the velocity profile at the inlet and outlet of the stented region where alterations in indices of WSS are most pronounced. For example, time-averaged WSS in the proximal portion of the stent ranged from 8.91 to 11.7 dynes/cm(2 )along the pericardial luminal surface and 4.26 to 4.88 dynes/cm(2 )along the myocardial luminal surface of curved coronary arteries as compared to 8.31 dynes/cm(2 )observed throughout the stented region of a straight vessel implanted with an equivalent stent. CONCLUSION: The current results predicting large spatial and temporal variations in WSS at specific locations in curved arterial 3D CFD simulations are consistent with clinically observed sites of restenosis. If the findings of this idealized study translate to the clinical situation, the regional geometry established immediately after stent implantation may predispose portions of the stented vessel to a higher risk of neointimal hyperplasia and subsequent restenosis

Theoretical Applications of the Impedance Catheter Technique of Ventricular Volume Measurement

Although measurement of left ventricular pressure has become a routine procedure in the cardiac catheterization laboratory, the same cannot be claimed for instantaneous changes of left ventricular chamber volume. This is unfortunate in light of the many useful indices of ventricular performance obtainable from the pressure-volume plane. The impedance catheter method of volume measurement, despite showing great promise as a real time measure of left ventricular chamber volume, has received only minimal clinical acceptance due to difficulties with calibration of the system. These difficulties stem from the broad assumptions inherent in the technique. The purpose of this investigation was to examine the validity of several of these assumptions using a two dimensional finite element model of the heart and surrounding tissues. In addition, an in vivo model was used to demonstrate the ability of this technique to quantify global changes in ventricular function during acute coronary artery occlusion

Impact of beating heart left atrial ablation on left-sided heart mechanics

ObjectiveThe cut-and-sew Cox–Maze procedure is the gold standard for surgical treatment of atrial fibrillation, but it is associated with long-term impairment of left atrial mechanical function. We developed a bipolar, irrigated radiofrequency ablation device. We hypothesized that beating heart radiofrequency left atrial ablation would result in minimal acute changes in left atrial hemodynamics.MethodsSix healthy subjects were studied. Combination pressure-conductance catheters were inserted into the left atrium and ventricle. With the use of the device, atrial ablation was performed on the beating heart without cardiopulmonary bypass, including electrical isolation of the posterior left atrium and atrial appendage myocardium. Simultaneous left-sided heart pressure–volume and intracardiac echocardiography data were acquired before ablation, after left atrial appendage ablation alone, and after all ablation (with and without appendage occlusion). The derived indices of left-sided heart mechanical function were examined.ResultsRelative to baseline, no significant diminishment in pressure–volume or intracardiac echocardiography-derived indices of global left-sided heart mechanical function were observed after ablation, with or without appendage occlusion. Mitral valve morphology and function were not significantly altered. A significant diminishment of atrial appendage systolic flow was noted after appendage ablation in association with spontaneous echocardiographic contrast in this region.ConclusionsIn this model, ablation does not seem to compromise global left-sided heart mechanical function. However, these findings mask regional diminishment in atrial appendage systolic function. This observation demonstrates that electrical isolation of the appendage should be accompanied by its occlusion or excision. Appendage occlusion after ablation does not seem to compromise left-sided heart mechanical function

Improved blood pressure control via a novel chronic disease management model of care in sub‐Saharan Africa: Real‐world program implementation results

Abstract A chronic disease management model of care (Empower Health) was launched in rural and urban areas of Ghana and Kenya in 2018. The goal was to improve disease awareness, reduce the burden of disease, and improve the clinical effectiveness and efficiency of managing hypertension. Leveraging the model, clinicians provide patients with tailored management plans. Patients accessed regular blood pressure checks at home, at the clinic, or at community‐partner locations where they received real‐time feedback. On the mobile application, clinicians viewed patient data, provided direct patient feedback, and wrote electronic prescriptions accessible through participating pharmacies. To date, 1266 patients had been enrolled in the “real‐world” implementation cohort and followed for an average of 351 ± 133 days across 5 facilities. Average baseline systolic blood pressure (SBP) was 145 ± 21 mmHg in the overall cohort and 159 ± 16 mmHg in the subgroup with uncontrolled hypertension (n = 743) as defined by baseline SBP ≥ 140 mmHg. SBP decreased significantly through 12 months in both the overall cohort (−9.4 mmHg, p < .001) and in the uncontrolled subgroup (−17.6 mmHg, p < .001). The proportion patients with controlled pressure increased from 46% at baseline to 77% at 12 months (p < .001). In summary, a new chronic disease management model of care improved and sustained blood pressure control to 12 months, especially in those with elevated blood pressure at enrollment