Prognostic role of pulmonary hemodynamics before transcatheter aortic valve replacement among patients with severe aortic stenosis

BACKGROUND

Pulmonary hypertension (PH) frequently co-exists in patients with severe aortic stenosis (AS). In this study, we sought to identify the implications of invasive pulmonary hemodynamics on major adverse cardiac events (MACE), biventricular function and NYHA functional class after transcatheter aortic valve replacement (TAVR).

METHODS

Invasive hemodynamics via right heart catheterization (RHC) were performed pre-TAVR. Patients were stratified per mean PA pressure (mPAP), diastolic pulmonary gradient (DPG) and pulmonary vascular resistance (PVR), and followed at 1-month and 1-year intervals up to 6 years. MACE outcomes included cardiovascular death and heart failure hospitalizations post-TAVR.

RESULTS

Among 215 patients, Kaplan-Meir estimates demonstrated an increased 1-year risk of MACE from 8% among those without pre-TAVR PH to 27% among patients with pre-existing PH. Specifically, the MACE risk was 32% among PH patients with PVR ≥ 3WU (p = .04) and 53% among PH patients with DPG ≥ 7 mm Hg (p < .01). On univariate Cox regression, RV stroke work index (RVSWI) (HR,1.02; p = .02), and pulmonary hemodynamic index (PHI) (HR,1.27; p = .047) were identified as additional predictors of MACE post-TAVR. On multivariable Cox regression analysis, SvO2 (HR, 0.95; p = .01) and PVR (HR, 1.2; p = .04) were demonstrated as predictive of MACE post-TAVR. A significant improvement in LVEF (2-Factor ANOVA, p < .01) and RV fractional area change (RVFAC%) (p < .01) was noted as assessed at baseline, 1-month and 1-year follow up post-TAVR. There was a significant interaction between pre-TAVR PH status and time post procedure with respect to NYHA functional class (p = .03), that is, the manner and degree of change in NYHA class over time depended on pre-TAVR PH status.

CONCLUSIONS

Defining invasive pulmonary hemodynamics, such as mPAP, PVR, and DPG among patients with severe AS undergoing TAVR has significant prognostic implications. Routine risk stratification by utilizing invasive hemodynamics can better identify patients who will have functional improvement and improved outcomes post-TAVR.

Ethnic and Racial Disparities in Resource Utilization and In-hospital Outcomes Among Those Admitted for Atrial Fibrillation: A National Analysis

INTRODUCTION

Disparities in overall outcomes for atrial fibrillation (AF) across racial and ethnic groups have been demonstrated in prior studies. We aim to evaluate in-hospital outcomes and resource utilization across three racial/ethnic groups with AF using contemporary data.

METHODS

We identified patients admitted with AF in the National Inpatient Sample registry from 2015 to 2018. ICD-10-CM codes were used to identify variables of interest. The primary outcomes were in-hospital complications and resource utilization.

RESULTS

There were 1,250,075 AF admissions. Our sample was made up of 85.49% White, 8.12% Black, and 6.38% Hispanic patients. Black patients were younger but had a higher burden of cardiovascular comorbidities including obesity, hypertension, and chronic kidney disease. Social determinants were also less favorable in Black patients, with a higher percentage of Medicaid insurance and a high proportion of patients being in the lowest percentile for household income. Total hospital charge was highest in Hispanic patients. Despite higher rates of gastrointestinal bleed, Black patients were least likely to undergo left atrial appendage occlusion device implantation. Black and Hispanic patients were less like to undergo catheter ablation therapy. Black race was an independent predictor of mortality, stroke, mechanical ventilation, acute kidney injury, hemodynamic shock, need for vasopressor, upper GI bleed, need for blood transfusion, total hospital charges, and length of stay when compared to other groups.

CONCLUSION

Disparities exist in the risk of AF, and its management among racial and ethnic groups. Health care costs and inpatient outcomes disproportionately impact minorities in the United States.

10-Year community prevalence and trends of severe asymptomatic hypertension among patients with hypertension in the USA: 2007-2016

BACKGROUND

Severe asymptomatic hypertension (SAH) is associated with significant health cost, morbidity and mortality.

AIM

Establish the nationwide prevalence, trends and associated sociodemographic characteristics of SAH among patients with hypertension in the USA.

METHODS

We utilized the National Health and Nutrition Examination data collected over five survey cycles (2007-2016). Included were participants aged 20-80 years with self-reported diagnosis of hypertension. SAH was defined as having a mean systolic blood pressure (SBP) ≥180 mmHg and/or mean diastolic blood pressure (DBP) ≥120 mmHg at the time of examination. The Chi square test was used to compare prevalence across different categories. Associations between sociodemographic variables and SAH were assessed using multivariate binary logistic regression.

RESULTS

The prevalence of SAH among patients with hypertension is 2.15% (95% CI 1.80-2.56), mainly explained by isolated mean SBP≥180 mmHg (86% of all cases), with no statistically significant change between 2007: 2.66% (95% CI 2.10-3.36) and 2016:2.61% [95% CI 1.73-3.94), p-trend = 0.17. Increasing age (OR 1.07, 95% CI 1.04-1.09), NH Blacks (OR 2.20, 95% CI 1.37-3.54), BMI< 25 (OR 2.52, 95% CI 1.48-4.28), lack of health insurance OR 4.92% (95% CI 2.53-9.54) and never married individuals (OR = 2.59%, 95% CI 1.20-5.60) were more likely to have SAH, comparatively. There was no significant association between duration of hypertension and SAH.

CONCLUSION

The prevalence of SAH in the USA is 2.15% and has been stable over the past decade. Our study underscores the importance of identifying barriers to screening and treatment of hypertension which is a major treatable risk factor for cardiovascular disease.

Transradial Versus Transfemoral Approach for Coronary Angiography in Females with Prior Bypass Surgery

Background Multiple studies have shown that trans-radial access (TRA) for women undergoing coronary angiography/intervention (CA/I) has a lower risk of vascular access site complications as compared with trans-femoral access (TFA). In patients who had previously undergone coronary artery bypass grafting (CABG), studies also showed no significant difference between TRA and TFA in terms of contrast amount (CA), procedure time (PT), and fluoroscopy time (FT). However, those studies mainly included men. Limited information is available on the relative merits of TRA as compared with TFA for cardiac catheterization in females who previously undergone CABG. The purpose of this study was to determine the efficacy and safety of TRA versus TFA in women with prior CABG surgery who are undergoing CA/I in regard to CA, PT, and FT. Methods In this single-center retrospective cohort study, females with a history of CABG who underwent CA/I in the period from January 2013 to September 2016 were included. A total of 584 patients were included and divided into two groups: TRA group (49 patients) and TFA group (535 patients). The primary endpoints were CA, PT, and FT. The means for the primary outcomes were compared between the two using the independent t-score test. Results A total of 584 female patients with a history of CABG had cardiac catheterization from January 2013 to September 2016 at our center. Trans-femoral access accounted for 91.6% (n=535) of the patients while trans-radial access accounted for 8.4% (n=49) of the patients. A comparison of procedural variables between TRA and TFA revealed that there was no statistical significance in procedure time, fluoroscopy time, or the contrast volume. The access site crossover rate was 6.12% (n=3) from radial to femoral while there was a 0% rate in the femoral to radial access. Conclusion The key findings of this study suggest that in female patients with a prior history of CABG, TRA is an equally reliable and efficacious approach for both diagnostic angiography and intervention compared to TFA.

A Unique Case Of Tenofovir-Induced DRESS Syndrome Associated With Raynaud's Of The Tongue

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a potentially fatal severe adverse reaction to medications. Numerous drugs have been implicated, with carbamazepine and allopurinol being the most common. Tenofovir-induced DRESS is extremely rare. We report a case of a 65-year-old male patient with a diffuse exfoliative maculopapular rash across his entire body of five weeks of duration. The patient also had icteric sclera, abnormal liver enzymes and Raynaud’s of the tongue, nose and the left fifth finger. After discontinuation of tenofovir, the case resolved over a span of ten days. A high index of suspicion is crucial along with the prompt withdrawal of the offending medication for a good outcome.

Osimertinib for the treatment of patients with EGFR mutation-positive non-small cell lung cancer

Epidermal growth factor receptor (EGFR) mutations, mostly seen in exon 19 or exon 21, are present in roughly 50% of patients with advanced non-small cell lung cancer (NSCLC) of Asian ethnicity compared with 12% in Caucasians. EGFR-mutated NSCLC patients have an increased sensitivity to EGFR tyrosine kinase inhibitors (TKIs), such as erlotinib, gefitinib or afatinib, showing superior response, progression-free survival and overall survival rates with EGFR-TKIs than with platinum doublet chemotherapy, which makes EGFR-TKIs the standard of care in this subgroup of NSCLC patients. This has been the most important step toward molecular-guided precision therapy for NSCLC. Despite the initial rapid and durable clinical responses, acquired resistance to EGFR-TKIs has been found to eventually develop in most cases, with disease progression observed mostly within 9-12 months after treatment. One of the most important mechanisms for resistance to EGFR-TKI therapy is the substitution of threonine to methionine (T790M) on exon 20 of the EGFR gene, which occurs in 49% to 60% of patients. Osimertinib mesylate (formerly AZD-9291) is a potent third-generation TKI which irreversibly inhibits mutated EGFR alleles, including T790M. This review summarizes osimertinib's pharmacology, pharmacokinetics, safety, side effects and clinical utility in the treatment of EGFR-mutated advanced NSCLC.

Quantal size is dependent on stimulation frequency and calcium entry in calf chromaffin cells

To what extent the quantal hypothesis of transmitter release applies to dense-core vesicle (DCV) secretion is unknown. We determined the characteristics of individual secretory events in calf chromaffin cells using catecholamine amperometry combined with different patterns of stimulation. Raising the frequency of action potential trains from 0.25-10 Hz in 2 mM [Ca(2+)]o or [Ca(2+)]o from 0.25-7 mM at 7 Hz elevated the amount released per event (quantal size). With increased stimulation, quantal size rose continuously, not abruptly, suggesting that release efficiency from a single population of DCVs rather than recruitment of different-sized vesicles contributed to the effect. These results suggest that catecholamine secretion does not conform to the quantal model. Inhibition of rapid endocytosis damped secretion in successive episodes, implying an essential role for this process in the recycling of vesicles needed for continuous secretion.

Enhancement of the dense-core vesicle secretory cycle by glucocorticoid differentiation of PC12 cells: characteristics of rapid exocytosis and endocytosis

The secretory cycle of dense-core vesicles (DCVs) in physiologically stimulated patch-clamped PC12 cells was analyzed using both amperometry and capacitance measurements. Untreated cells had low or undetectable Ca currents and sparse secretory responses to short depolarizations. Dexamethasone (5 microM) treatment for 5-7 d tripled Ca current magnitude and dramatically increased quantal secretion in response to depolarization with action potentials. Such cells expressed L-, N-, and P-type Ca channels, and depolarization evoked rapid catecholamine secretion recorded as amperometric spikes; the average latency was approximately 50 msec. These spikes were much smaller and shorter than those of primary adrenal chromaffin cells, reflecting the smaller size of DCVs in PC12 cells. Depolarizing pulse trains also elicited a rapid increase in membrane capacitance corresponding to exocytosis in differentiated but not in naïve cells. On termination of stimulation, membrane capacitance declined within 20 sec to baseline indicative of rapid endocytosis (RE). RE did not take place when secretion was stimulated in the presence of Ba or Sr, indicating that RE is Ca-specific. RE was blocked when either anti-dynamin antibodies or the pleckstrin homology domain of dynamin-1 was loaded into the cell via the patch pipette. These studies indicate that neuroendocrine differentiation of PC12 cells with glucocorticoids enhances the development of the excitable membrane and increases the coupling between Ca channels and vesicle release sites, leading to rapid exocytosis and endocytosis. Slow catecholamine secretion in undifferentiated cells may be caused in part by a lack of localized secretory machinery rather than being an intrinsic property of dense-core vesicles.

Ca(2+)-dependent activator protein for secretion is critical for the fusion of dense-core vesicles with the membrane in calf adrenal chromaffin cells

Calcium-dependent activator protein for secretion (CAPS) is a neural/endocrine cell-specific protein that has been shown to function at the Ca(2+)-dependent triggering step of dense-core vesicle (DCV) exocytosis in permeabilized PC12 cells. To evaluate the function of CAPS under physiological conditions, we introduced affinity-purified anti-CAPS IgGs into calf adrenal chromaffin (AC) cells via a patch pipette and tested the kinetics of catecholamine secretion using both amperometric and membrane capacitance techniques. The antibodies reacted with a single major approximately 145 kDa protein in AC cells based on immunoblot analysis. AC cells stimulated with sequential trains of action potentials at 7 Hz resulted in successive secretory episodes of equivalent magnitude. When either of two different anti-CAPS IgGs or their Fab fragments were present, a rapid and progressive inhibition of catecholamine release ensued to a maximum of >80%. The effect was specific because preabsorption of IgGs with the respective antigens ablated the inhibitory effect, and the IgGs had no effect on Ca currents. CAPS immunoneutralization not only reduced the number of amperometric spikes but markedly altered the kinetic characteristics of the residual events. The remaining spikes were much smaller (by 85%) and broader (by approximately 3.5-fold) than those in control cells, suggesting that CAPS plays a role in determining release of vesicle contents via the fusion pore. Anti-CAPS IgGs also slowed the rate of the initial exocytotic capacitance burst, representing the docked-and-primed vesicle pool, by approximately 90% but had no effect on the kinetics of rapid endocytosis. These results suggest that CAPS is a key component regulating the fusion of DCVs to the plasma membrane, and possibly fusion pore dilation, in catecholamine secretion from AC cells.

Timing of dense-core vesicle exocytosis depends on the facilitation L-type Ca channel in adrenal chromaffin cells

Secretion from dense-core vesicles is reputedly much slower than that from typical synaptic vesicles, possibly because of noncolocalization of Ca channels and release sites. We reinvestigated this question by measuring the kinetics of catecholamine release in chromaffin cells from calf and adult bovines. Amperometric recording from calf chromaffin cells stimulated by action potentials exhibited two latencies of secretion that depended on both the frequency of stimulation and the pathway of Ca entry. Short-latency responses (<25 msec delay; "strongly coupled") appeared at low (0.25 and 1 Hz) and high (7 Hz) frequencies and were entirely dependent on recruitment of "facilitation" L-type Ca channels as revealed by nisoldipine blockade. Long-latency responses (>25 msec delay; "weakly coupled") were more apparent at higher frequencies (7 Hz) and were substantially reduced by toxins that blocked N- and P-type Ca channels. Ca current recordings revealed that adult bovine chromaffin cells lack facilitation channels; virtually all secretion was weakly coupled in these cells. The mean delay of the strongly coupled signal was approximately 3 msec after the peak of the action potential (at 24 degreesC), indicating that dense-core vesicles can exhibit a rate of exocytosis approaching that occurring in neurons. Although other explanations are possible, these results are consistent with the idea that facilitation Ca channels are colocalized with release sites in calf chromaffin cells. Calculations based on a model incorporating this assumption suggest that these channels must be within 13 nm of secretory sites to account for such rapid exocytosis.

Secretion: dense-core vesicles can kiss-and-run too

New measurements show that the entire transmitter contents of a dense-core vesicle can be released within a second through a narrow fusion pore that opens transiently. With other results, this raises the possibility that some dense core vesicles may, like small synaptic vesicles, undergo immediate recycling.

Calmodulin is the divalent cation receptor for rapid endocytosis, but not exocytosis, in adrenal chromaffin cells

Exocytosis and the ensuing rapid endocytosis in adrenal chromaffin cells are both Ca(2+)-dependent phenomena but differ in their divalent cation specificity, implying distinct Ca2+ receptors for the two processes. To ascertain whether calmodulin is the Ca2+ receptor for either process, we blocked its function by introducing calmodulin-binding peptides or anti-calmodulin antibodies into these cells. Exo/endocytosis was followed by measurement of cell membrane capacitance. Rapid endocytosis, but not exocytosis, was abolished by these treatments, indicating that calmodulin is the Ca2+ receptor for rapid endocytosis but is not involved in exocytosis. The principal calmodulin target is not protein phosphatase-2B, as antagonism of this enzyme did not inhibit but accelerated rapid endocytosis. Calmodulin may thus regulate both the rate and extent of rapid endocytosis by distinct pathways.

ATP and G proteins affect the runup of the Ca2+ current in bovine chromaffin cells

The Ca2+ current recorded by the whole-cell technique in chromaffin cells shows, before the often described rundown, a transient facilitation or runup. Initial current amplitude was 570 +/- 165 pA and then it increased by 49 +/- 23% (n = 19, SD) over 2 +/- 1 min in the absence of adenosine 5'-triphosphate (ATP). In the presence of ATP, this process occurred with the same magnitude but it was slowed in a dose-dependent manner, lasting 17 +/- 2 min with 2 mM ATP (n = 8). Since adenosine 5'-diphosphate (ADP) does not reproduce this ATP effect, a complex series of phosphorylations is likely to intervene and we show that, at least, a cAMP-dependent i.e., cyclic adenosine monophosphate) phosphorylation occurs. Pertussis toxin (PTX) pretreatment yielded an already maximal Ca2+ current (around 1000 pA) at the time of the patch rupture, which only slightly increased thereafter (10%, n = 11). Also, guanosine 5'-diphosphate (GDP) and guanosine 5'-O-(2-thiodiphosphate) (GDP[ beta s]), induced a fast runup, which was absent in the presence of GTP. Furthermore, we show that facilitation does not occur in the presence of dihydrophyridine (DHP) antagonists. Globally, our data suggest that an ATP-dependent phosphorylation stabilizes the inhibitory control exerted by a PTX-sensitive G protein and, as a result, slows down the facilitation of L-type Ca2+ channels. The recruitment of L-type channels can also be facilitated by the application of a DHP agonist or a depolarizing prepulse protocol.l We show that these processes are only effective over a period which parallels the runup and are not additive to it.(ABSTRACT TRUNCATED AT 250 WORDS)

ADP exerts a protective effect against rundown of the Ca2+ current in bovine chromaffin cells

In isolated chromaffin cells, the high-voltage-activated Ca2+ current, recorded using 5 mM Ca2+ as the divalent charge carrier, exhibits rundown within 10 min, which is delayed for 1 h at least by the addition of 1 mM adenosine 5'-triphosphate (ATP) to the pipette medium. The mechanism of this stabilizing action of ATP has been examined. ATP action is dose dependent; the rundown process, which was delayed at concentrations below 0.4 mM, was totally abolished at higher concentrations. The requirement for ATP was shown to be quite strict: 2 mM inosine 5'-triphosphate (ITP) could not replace ATP, whereas guanosine 5'-triphosphate (GTP) could, but at higher concentrations. This effect of ATP was shown to require the presence of MgCl2 and the liberation of a phosphate group since the ATP analogue 5'-adenylyl-imidodiphosphate (AMP-PNP) could not act as a substitute for ATP, suggesting an action through either adenosine 5'-diphosphate (ADP) or a phosphorylation step. ADP, in the presence of Mg2+ only, could replace ATP in the same concentration range. This effect was shown to be specific to ADP; it was maintained after blocking the pathways which convert ADP into ATP, and could not be mimicked by guanosine 5'-diphosphate (GDP). Similarly, ATP and ADP effects were abolished at an increased internal Ca2+ concentration (pCa 6 instead of pCa 7.7, where pCa = -log10[Ca2+]). Nevertheless, the presence of 1 mM Mg-ADP in the bathing solution did not prevent the rundown of the Ca2+ channels when going to the inside-out patch recording configuration.(ABSTRACT TRUNCATED AT 250 WORDS)

Evolution of the Ca2+ current during dialysis of isolated bovine chromaffin cells: effect of internal calcium

We have examined the internal Ca(2+)-dependence of the long-term evolution of whole cell high voltage activated Ca current in chromaffin cells. The evolution of the peak Ca current was characterized by 2 distinct phases: after an initial facilitation, there followed a rundown, which represented a reduction by 70% within some 10 min. The rundown process was shown not to depend on Ca2+ entry nor on membrane depolarization. It resulted from cell dialysis with a saline solution and, once initiated, it proceeded at a rate of 0.28 min-1 at 4 different Ca2+ concentrations (pCa 5-9). The facilitation is also initiated by cell dialysis but this process developed faster at higher internal Ca2+ concentrations. Thus, globally, high-voltage activated Ca2+ current runs down faster when using a recording pipette solution with a higher internal Ca2+ concentration (pCa 5 or 6). Some leupeptin-sensitive proteases may be involved in the initiation of facilitation and rundown processes.

Voltage-dependent calcium entry in confluent bovine capillary endothelial cells

Confluent bovine capillary endothelial cells display, when examined for voltage-dependent calcium entries using cell-attached channel recordings, two types of Ca2+ channels (4 and 23.5 pS in 110 mM Ba2+) both sensitive to the dihydropyridine Ca agonist BAY K 8644. In contrast to isolated cells, confluent cells display no T-type, low threshold activity, and Ca currents were typically only elicited at very depolarized potentials. In these cells, voltage-dependent calcium entries will only be made operative by substances able to shift their activation towards the resting potential.

Voltage-gated Ca entry in isolated bovine capillary endothelial cells: evidence of a new type of BAY K 8644-sensitive channel

Isolated bovine capillary endothelial cells have been examined for voltage-dependent Ca entry. All cells displayed a low threshold activity, with the main characteristics of a T-type transient current, when examined using whole-cell recording for activation and inactivation and cell-attached conditions or inside-out patches for the elementary conductance (8 pS). 25% of the cells displayed an additional sustained current in 5 mM CaCl2 above -40 mV, which was enhanced by application of BAY K 8644, but almost insensitive to superfusion with nicardipine. Two types of channels (2.8 and 21 pS, in 110 mM BaCl2) were shown to have a BAY K 8644 sensitivity. The large conductance channels were L-type channels. The smaller events were elicited at more hyperpolarized potentials (by some 30 mV). Their mean open time was 16 ms in control conditions. In presence of BAY K 8644, additional long open times were observed (up to 100 ms as compared to 7.8 ms for the time constants of the slow mode of the L-type channel). We refer to these channels as SB channels: of small conductance and sensitive to BAY K 8644. In the presence of nicardipine, SB channels are not noticeably modified, in contrast to the L-type openings which are abolished. Also, SB open times are close to control values when nicardipine is added after a BAY K 8644 application. We suggest that, at physiological concentrations of divalent ions, an SB-type activity is elicited above -40 mV which generates the low threshold sustained current.