Obstructive sleep apnea and hypertension-mediated organ damage in nonresistant and resistant hypertension

The potential role of obstructive sleep apnea (OSA) in hypertension-mediated organ damage (HMOD) may be influenced by the presence of resistant hypertension (RH). Herein, we enrolled patients with hypertension from a tertiary center for clinical evaluation and performed a sleep study to identify OSA (apnea-hypopnea index ≥15 events/h) and a blinded analysis of four standard HMOD parameters (left ventricular hypertrophy [LVH], increased arterial stiffness [≥10 m/s], presence of retinopathy, and nephropathy). RH was diagnosed based on uncontrolled blood pressure (BP) (≥140/90 mmHg) despite concurrent use of at least three antihypertensive drug classes or controlled BP with concurrent use of ≥4 antihypertensive drug classes at optimal doses. To avoid the white-coat effect, ambulatory BP monitoring was performed to confirm RH diagnosis. One-hundred patients were included in the analysis (mean age: 54 ± 8 years, 65% females, body mass index: 30.4 ± 4.5 kg/m²). OSA was detected in 52% of patients. Among patients with non-RH (n = 53), the presence of OSA (52.8%) was not associated with an increased frequency of HMOD. Conversely, among patients with RH, OSA (51.1%) was associated with a higher incidence of LVH (RH-OSA,61%; RH + OSA,87%; p = 0.049). Logistic regression analysis using the total sample revealed that RH (OR:7.89; 95% CI:2.18-28.52; p = 0.002), systolic BP (OR:1.04; 95% CI:1.00-1.07; p = 0.042) and OSA (OR:4.31; 95% CI:1.14-16.34; p = 0.032) were independently associated with LVH. No significant association was observed between OSA and arterial stiffness, retinopathy, or nephropathy. In conclusion, OSA is independently associated with LVH in RH, suggesting a potential role of OSA in RH prognosis.

Effects of CPAP on Metabolic Syndrome in Patients With OSA: A Randomized Trial

BACKGROUND

OSA is associated with metabolic syndrome (MS), but it is unclear whether OSA treatment with CPAP can revert MS.

RESEARCH QUESTION

Does OSA treatment with CPAP per se have effects on the MS reversibility and the associated metabolic, adiposity and vascular parameters?

STUDY DESIGN AND METHODS

The TREATOSA-MS trial is a randomized placebo-controlled trial that enrolled adult patients with a recent diagnosis of MS and moderate or severe OSA (apnea-hypopnea index [AHI], ≥ 15 events/h) to undergo therapeutic CPAP or nasal dilator strips (placebo group) for 6 months. Before and after each intervention, we measured anthropometric variables, BP, glucose, and lipid profile. To control potential-related mechanisms and consequences, we also measured adiposity biomarkers (leptin and adiponectin), body composition, food intake, physical activity, subcutaneous and abdominal fat (visceral and hepatic fat), and endothelial function.

RESULTS

One hundred patients (79% men; mean age, 48 ± 9 years; BMI, 33 ± 4 kg/m²; AHI, 58 ± 29 events/h) completed the study (n = 50 per group). The mean CPAP adherence was 5.5 ± 1.5 h/night. After 6 months, most patients with OSA randomized to CPAP retained the MS diagnosis, but the rate of MS reversibility was higher than observed in the placebo group (18% vs 4%; OR, 5.27; 95% CI, 1.27-35.86; P = .04). In the secondary analysis, CPAP did not promote significant reductions in the individual components of MS, weight, hepatic steatosis, lipid profile, adiponectin, and leptin, but did promote a very modest reduction in visceral fat and improved endothelial function (all analyses were adjusted for baseline values).

INTERPRETATION

Despite the higher rate of MS reversibility after CPAP therapy as compared with placebo, most patients retained this diagnosis. The lack of significant or relevant effects on adiposity biomarkers and depots supports the modest role of OSA in modulating MS.

TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT02295202; URL: www.

CLINICALTRIALS

gov.

Diastolic and systolic left ventricular dysfunction and mortality in chronic kidney disease patients on haemodialysis

AIMS

Left ventricular diastolic dysfunction (LVDD) and LV systolic dysfunction (LVSD) are prevalent in CKD, but their prognostic relevance is debatable. We intent to verify whether LVDD and LVSD are independently predictive of all-cause mortality and if they have comparable or different effects on outcomes.

METHODS

A retrospective analysis was conducted of the echocardiographic data of 1285 haemodialysis patients followed up until death or transplantation. LVDD was classified into 4 grades of severity. Endpoint was all-cause mortality.

RESULTS

During a follow-up of 30 months, 419/1285 (33%) patients died, 224 (53%) due to CV events. LVDD occurred in 75% of patients, grade 1 DD was the prevalent diastolic abnormality, and pseudonormal pattern was the predominant form of moderate-severe DD. Moderate-severe LVDD (HR 1.379, CI% 1.074-1.770) and LVSD (HR 1.814, CI% 1.265-2.576) independently predicted death; a graded, progressive association was found between LVDD categories and the risk of death; and the impact of isolated severe-moderate LVDD on the risk of death was comparable to that exercised by isolated compromised LV systolic function.

CONCLUSION

Moderate-severe LVDD and LVSD were independently associated with a higher probability of death and had a similar impact on survival. A progressive association was observed between LVDD grades and mortality.

High Dialysate Calcium Concentration is Associated with Worsening Left Ventricular Function

Dialysate calcium concentration (d[Ca]) might have a cardiovascular impact in patients on haemodialysis (HD) since a higher d[Ca] determines better hemodynamic tolerability. We have assessed the influence of d[Ca] on global longitudinal strain (GLS) by two-dimensional echocardiography using speckle-tracking imaging before and in the last hour of HD. This is an observational crossover study using d[Ca] 1.75 mmol/L and 1.25 mmol/L. Ultrafiltration was the same between interventions; patients aged 44 ± 13 years (N = 19). The 1.75 mmol/L d[Ca] was associated with lighter drop of blood pressure. Post HD serum total calcium was higher with d[Ca] 1.75 than with 1.25 mmol/L (11.5 ± 0.8 vs. 9.1 ± 0.5 mg/dL, respectively, p < 0.01). In almost all segments strain values were significantly worse in the peak HD with 1.75 mmol/L d[Ca] than with 1.25 mmol/L d[Ca]. GLS decreased from −19.8 ± 3.7% at baseline to −17.3 ± 2.9% and −16.1 ± 2.6% with 1.25 d[Ca] and 1.75 d[Ca] mmol/L, respectively (p < 0.05 for both d[Ca] vs. baseline and 1.25 d[Ca] vs. 1.75 d[Ca] mmol/L). Factors associated with a worse GLS included transferrin, C-reactive protein, weight lost, and post dialysis serum total calcium. We concluded that d[Ca] of 1.75 mmol/L was associated with higher post dialysis serum calcium, which contributed to a worse ventricular performance. Whether this finding would lead to myocardial stunning needs further investigation.

Abstract 011: Regression of Left Ventricle Hypertrophy and Improvement of Ventricular Dysfunction After Renal Revascularization is Dependent of Blood Pressure Response and Etiology of Renal Artery Stenosis

Background: Renovascular hypertension promotes humoral and hemodynamic overload on the cardiovascular system and it is unknown the clinical impact of the correction of renal artery stenosis (RAS) on the structure and function of the heart.We aimed to evaluate the effect of RAS correction on blood pressure (BP) and left ventricle (LV) morphology, function and mass index (LVMI).

Methods: Ninety-eight hypertensive patients with significant RAS (> 70%) undergoing percutaneous intervention (26%) or surgical treatment (74%) with a minimum follow-up of 12 months entered the study. We analyzed echocardiographic measurements , including LVMI and ejection fraction (EF) before and after correction of RAS. The BP response after treatment was based on AHA guidelines: cured (BP<140/90 without drugs), improved (BP <140/90 with reduction of number of drugs) and failure.

Results: The mean age was 46 ±17 years and 60% were female. The etiology of RAS was atherosclerosis (59%), arteritis (21%) and dysplasia (20%). Before treatment, echocardiography showed LVMI=162 ± 60 g/m2, 73.5% had LV hypertrophy (LVMI > 125 g/m2) and 13 patients had systolic dysfunction (EF<50%). In a mean follow-up of 51 ± 40 months, 62% were considered cured or improved (Benefit group) and 38% as Failure. In the Benefit group, mean LVMI in the follow-up was lower than in Failure group (129 ±44 vs 169 ±42 g/m2, p<.05). The reduction of LVMI was significantly greater in Benefit than in Failure group (23 ±5 vs. 9±9 g/m2, p<.03). The systolic function normalized in 10 from 13 patients with previous dysfunction. The mean LVMI reduction was higher in patients with arteritis than in those with atherosclerosis or dysplasia.

Conclusion: Successful renal revascularization promotes significant reduction of LV hypertrophy and normalize previously impaired systolic dysfunction in patients with RAS. The regression of ventricle mass is dependent of BP response after treatment and is more impressive in patients with arteritis.

Impact of hypertension severity on arterial stiffness, cerebral vasoreactivity, and cognitive performance

Aging, hypertension (HTN), and other cardiovascular risk factors contribute to structural and functional changes of the arterial wall.

Higher arterial stiffness is associated with lower cognitive performance in patients with hypertension

Cognitive impairment and elevated arterial stiffness have been described in patients with arterial hypertension, but their association has not been well studied. We evaluated the correlation of arterial stiffness and different cognitive domains in patients with hypertension compared with those with normotension. We evaluated 211 patients (69 with normotension and 142 with hypertension). Patients were age matched and distributed according to their blood pressure: normotension, hypertension stage 1, and hypertension stage 2. Cognitive function was assessed using the Mini-Mental State Examination, Montreal Cognitive Assessment, and a battery of neuropsychological evaluations that assessed six main cognitive domains. Pulse wave velocity was measured using a Complior device, and carotid properties were assessed by radiofrequency ultrasound. Central arterial pressure and augmentation index were obtained using applanation tonometry. The hypertension stage 2 group had higher arterial stiffness and worse performance either by Mini-Mental State Examination (26.8±2.1 vs 27.3±2.1 vs 28.0±2.0, P=.003) or the Montreal Cognitive Assessment test (23.4±3.5 vs 24.9±2.9 vs 25.6±3.0, P<.001). On multivariable regression analysis, augmentation index, intima-media thickness, and pulse wave velocity were the variables mainly associated with lower cognitive performance at different cognitive domains. Cognitive impairment in different domains was associated with higher arterial stiffness.

Hypertension Severity Is Associated With Impaired Cognitive Performance

BACKGROUND

Most evidence of target-organ damage in hypertension (HTN) is related to the kidneys and heart. Cerebrovascular and cognitive impairment are less well studied. Therefore, this study analyzed changes in cognitive function in patients with different stages of hypertension compared to nonhypertensive controls.

METHODS AND RESULTS

In a cross-sectional study, 221 (71 normotensive and 150 hypertensive) patients were compared. Patients with hypertension were divided into 2 stages according to blood pressure (BP) levels or medication use (HTN-1: BP, 140-159/90-99 or use of 1 or 2 antihypertensive drugs; HTN-2: BP, ≥160/100 or use of ≥3 drugs). Three groups were comparatively analyzed: normotension, HTN stage 1, and HTN stage 2. The Mini-Mental State Examination, Montreal Cognitive Assessment, and a validated comprehensive battery of neuropsychological tests that assessed 6 main cognitive domains were used to determine cognitive function. Compared to the normotension and HTN stage-1, the severe HTN group had worse cognitive performance based on Mini-Mental State Examination (26.8±2.1 vs 27.4±2.1 vs 28.0±2.0; P=0.004) or Montreal Cognitive Assessment (23.4±3.7 vs 24.9±2.8 vs 25.5±3.2; P<0.001). On the neuropsychological tests, patients with hypertension had worse performance in language, processing speed, visuospatial abilities, and memory. Age, hypertension stage, and educational level were the best predictors of cognitive impairment in patients with hypertension in different cognitive domains.

CONCLUSIONS

Cognitive impairment was more frequent in patients with hypertension, and this was related to hypertension severity.

Renal artery stenosis predicts coronary artery disease in patients with hypertension

In hypertensive patients with indication of renal arteriography to investigate renal artery stenosis (RAS) there are no recommendations regarding when to investigate coronary artery disease (CAD). Moreover, the predictors of CAD in patients with RAS are not clear. We aimed to evaluate the frequency and the determinants of CAD in hypertensive patients referred to renal angiography. Eighty-two consecutive patients with high clinical risk suggesting the presence of RAS systematically underwent renal angiography and coronary angiography during the same procedure. Significant arterial stenosis was defined by an obstruction ≥ 70% to both renal and coronary territories. Significant CAD was present in 32/82 (39%) and significant RAS in 32/82 (39%) patients. Both CAD and RAS were present in 25.6% from the 82 patients. Patients with severe CAD were older (63 ± 12 vs. 56 ± 13 years; p = 0.03) and had more angina (41 vs. 16%; p = 0.013) compared to patients without severe CAD. Significant RAS was associated with an increased frequency of severe CAD compared to patients without significant RAS (66% vs. 22%, respectively; p<0.001). Myocardial scintigraphy showed ischemia in 21.8% of the patients with CAD. Binary logistic regression analysis showed that RAS ≥ 70% was independently associated with CAD ≥ 70% (OR: 11.48; 95% CI 3.2-40.2; p<0.001), even in patients without angina (OR: 13.48; 95%CI 2.6-12.1; p<0.001). Even considering a small number of patients with significant RAS, we conclude that in hypertensive patients referred to renal angiography, RAS ≥ 70% may be a strong predictor of severe CAD, independently of angina, and dual investigation should be considered.

Lamotrigine analysis in blood and brain by high-performance liquid chromatography

A reversed-phase high-performance liquid chromatography assay was developed and validated to determine plasma and brain lamotrigine concentrations allowing pharmacokinetic-pharmacodynamic studies of this new antiepileptic drug in patients and laboratory animals. Lamotrigine and its internal standard were extracted, under alkaline conditions, from plasma and brain homogenate, into ethyl acetate; brain proteins were previously precipitated with trichloroacetic acid. The method was linear between 0.1 and 15.0 mg/l for plasma, with a detection limit of 0.008 mg/l, and between 0.1 and 5.0 mg/l for brain homogenate, with a detection limit of 0.023 mg/l. The method proved to be simple, useful and appropriate, not only for clinical and experimental research, but also for routine monitoring of lamotrigine concentrations in patients.

Regulation of intracellular [Ca2+] and GABA release by presynaptic GABAB receptors in rat cerebrocortical synaptosomes

In this study we determined the changes in the intracellular free Ca2+ concentration, associated with the inhibitory modulation of the exocytotic release of GABA by GABAB receptor activation in rat cerebrocortical synaptosomes. We observed that SK&F 97541 and (-)baclofen both act as agonists of the presynaptic GABAB receptors in modulating GABA release and Ca2+ influx due to KCl (10 mM) depolarization, but SK&F 97541 is more potent than (-)baclofen in modulating both Ca2+ influx and GABA release. Thus, activation of GABAB receptors by either SK&F97541 (10 microM) or by (-)baclofen (100 microM) caused about 18% inhibition of the increase in [Ca2+]i, due to KCl depolarization, and inhibited the [3H]GABA release by about 30%. The pharmacological similarities of the GABAB receptor activation in producing inhibition of both calcium channel mediated influx of Ca2+ and transmitter release suggest that presynaptic inhibition of GABA release by GABAB receptor activation may result, at least in part, from inhibition of Ca2+ influx through P-type (or possibly Q-type) Ca2+ channels, sensitive to omega-Agatoxin IVA (200 nM). Furthermore, modulation of GABA release of GABAB receptors was abolished by preincubation with pertussis toxin, suggesting that a pertussis toxin sensitive G protein may be the coupling factor between GABAB receptors and the voltage-dependent Ca2+ channels associated with the exocytotic release of GABA in rat cerebrocortical nerve terminals.

Pharmacological characterization of the postsynaptic alpha-adrenoceptors in human uterine artery

Prazosin and yohimbine were used to differentiate postjunctional alpha-adrenoceptors in the human uterine artery in-vitro. Two postjunctional alpha-adrenoceptor subtypes were distinguished by the affinities of the receptor for yohimbine and prazosin. The pA2 for prazosin was 8.91 against phenylephrine with a slope not significantly different from unity (0.91), and the pA2 for yohimbine was 7.25 against naphazoline and 8.70 against clonidine, with slopes not significantly different from unity (1.11 and 1.18, respectively). Yohimbine was not very active against phenylephrine, while prazosin was very active against the mixed and selective alpha 2-adrenoceptor agonist noradrenaline and clonidine; the intercepts of the Schild plot were 8.80 and 8.82 but with slopes significantly less than unity (0.77 and 0.67, respectively). Prazosin competitively antagonized phenylephrine at the alpha 1-adrenoceptor, whereas yohimbine competitively antagonized naphazoline and clonidine at the alpha 2-adrenoceptor. It is concluded that both alpha 1- and alpha 2-adrenoceptors are present in the human uterine artery.