Pierre Fesler

Effects of levosimendan versus dobutamine on pressure load-induced right ventricular failure.

Objective:A transient increase in pulmonary arterial (PA) pressure can persistently depress right ventricular (RV) contractility. We investigated the effects of dobutamine and levosimendan on RV-PA coupling in this model of RV failure. Design:Prospective, controlled, randomized animal study. Setting:University research laboratory. Subjects:Fifteen anesthetized dogs. Interventions:Transient (90-min) PA constriction to induce persistent RV failure. Random assignment to dobutamine 5 and 10 &mgr;g/kg/min or levosimendan 12 &mgr;g/kg for 10 mins followed by 0.1 and 0.2 &mgr;g/kg/min. Measurements and Main Results:We measured PA distal resistance and proximal elastance by pressure-flow relationships and vascular impedance. We measured RV contractility by the end-systolic pressure-volume relationship (Ees), PA effective elastance by the end-diastolic to end-systolic relationship (Ea), and RV-PA coupling efficiency by the Ees/Ea ratio. PA constriction persistently increased PA resistance and elastance, increased Ea from 0.95 ± 0.07 to 3.01 ± 0.28 mm Hg/mL, decreased Ees from 1.17 ± 0.09 to 0.58 ± 0.07 mm Hg/mL, and decreased Ees/Ea from 1.26 ± 0.09 to 0.22 ± 0.03 (p < .05). Dobutamine did not affect pulmonary hemodynamics, markedly increased RV contractility, and improved RV-PA coupling. Levosimendan decreased PA resistance and elastance, increased RV contractility, and restored RV-PA coupling. Compared with dobutamine, levosimendan decreased RV afterload and therefore better restored RV-PA coupling at similar inotropic state. Conclusions:A transient increase in PA pressure persistently worsens PA hemodynamics, RV contractility, RV-PA coupling, and cardiac output. Levosimendan restores RV-PA coupling better than dobutamine because of similar inotropic effects and additional pulmonary vasodilatory effects.

Relative Glomerular Hyperfiltration in Primary Aldosteronism

Experimental and clinical data suggest that primary aldosteronism (PA) may be associated with cardiovascular hypertrophy and fibrosis, in part independent of the BP level. Whether PA may also result in specific deleterious effects on the kidneys was less studied. In 25 patients with tumoral PA, renal studies (urinary excretion of proteins, GFR, and effective renal plasma flow [ERPF], as clearances of technetium-labeled diethylene triaminopentaacetic acid and 131I-ortho iodohippurate, respectively) were performed both before and 6 mo after surgical cure. A control group consisting of patients with essential hypertension (EH) was studied before and after 6 mo of antihypertensive therapy. At baseline, PA and EH patients were similar with respect to demographic data, duration and level of hypertension, and GFR and ERPF. Urinary excretion of albumin and beta2 microglobulin were higher in PA than EH (88 +/- 26 versus 39 +/- 12 and 0.91 +/- 0.23 versus 0.26 +/- 0.19 mg/24 h, respectively; both P < 0.05). Adrenalectomy was followed by a decrease in arterial BP (by 28 +/- 3/13 +/- 2 mmHg), urinary excretion of albumin and beta2 microglobulin (by 48 +/- 19 and 0.53 +/- 0.21 mg/24 h, respectively), and GFR and ERPF (by 15 +/- 3 and 54 +/- 15 ml/min per 1.73 m(2), respectively). In EH, a similar decrease in pressure was associated with a decrease in albuminuria but no change in GFR or ERPF. In 17 of the 25 PA patients who received a 6-mo treatment of spironolactone, both GFR and ERPF decreased in parallel with BP, similar to what was observed after surgery. These data suggest that PA was associated with relative hyperfiltration, unmasked after suppression of aldosterone excess.

Elevated Pulse Pressure Is Associated With Low Renal Function in Elderly Patients With Isolated Systolic Hypertension

In the past decade, pulse pressure has emerged as a strong predictor of cardiovascular morbidity and mortality. During aging, elevation of pulse pressure is a consequence of stiffening of the arterial wall. The relationship between pulse pressure and the renal aging process was studied in a cohort of 212 patients with never-treated isolated systolic hypertension. Glomerular filtration rate and effective renal plasma flow were measured using constant infusion of technetium 99m (99mTc)-DTPA and 131I-ortho-iodohippurate, respectively, and timed urine collections. The relationship between pulse pressure and renal function was studied using a linear regression model in the total population and in 40 to 49, 50 to 59, and 60 years and older age categories. In the whole population, there was an inverse relationship between pulse pressure and glomerular filtration rate; however, this relation did not persist after adjustment for age. In fact, the inverse relationship between pulse pressure and glomerular filtration rate was only present in patients 60 years of age or older. This relationship in elderly patients remained after adjustment for age, gender, MAP, and cardiovascular risk factors (P=0.006). It is suggested that pulse pressure, a marker of arterial stiffening, may have a detrimental influence on the age-related decline in glomerular filtration rate, after 60 years of age in patients with never-treated isolated systolic hypertension.

Microalbuminuria in Type 2 Diabetes and Hypertension : A marker, treatment target, or innocent bystander?

Albuminuria is a well-known predictor of poor renal outcomes in patients with type 2 diabetes and in essential hypertension (1–4). Albuminuria has also been shown more recently to be a predictor of cardiovascular outcomes in these populations (5–8). There is emerging data that reduction of albuminuria leads to reduced risk of adverse renal and cardiovascular events (9–12). It has become increasingly clear that albuminuria should not only be measured in all patients with type 2 diabetes and hypertension, but also steps should be taken to suppress albuminuria to prevent future renal and cardiovascular adverse events. This review discusses the measurement of albuminuria and summarizes the current literature on the association between albuminuria and adverse cardiovascular and renal outcomes in type 2 diabetes and hypertension. It also summarizes the evidence that reduction of albuminuria leads to improvement in the risk profiles of these patients. Microalbuminuria is defined as levels of albumin ranging from 30 to 300 mg in a 24-h urine collection (13). Overt albuminuria, macroalbuminuria, or proteinuria is defined as a urinary albumin excretion of ≥300 mg/24 h. Urinary albuminuria comprises 20–70% or urinary total protein excretion. Measuring urinary albumin excretion by dipstick without simultaneously measuring creatinine is subject to false-negative and false-positive results due to variations in urine concentration caused by hydration level (13). Although urinary dipsticks are acceptable for quick screening, other more precise measurements should be done to quantify urinary albumin excretion rates (AERs). Albuminuria can be measured in several ways (Table 1): 1 ) measurement of albumin-to-creatinine ratio (ACR) in a random or first morning spot collection, 2 ) 24-h urine collection with measurement of creatinine to verify adequacy of the collection, and 3 ) timed (4-h or overnight) urine collections (13). Although the 24-h urine collection would overcome issues of diurnal variation …

Signaling molecules in overcirculation-induced pulmonary hypertension in piglets: effects of sildenafil therapy.

Background—The phosphodiesterase type-5 (PDE-5) inhibitor sildenafil has been reported to improve pulmonary arterial hypertension (PAH), but the mechanisms that account for this effect are incompletely understood. Severe pulmonary hypertension has been characterized by defects in a signaling pathway involving angiopoietin-1 and the bone morphogenetic receptor-2 (BMPR-2). We investigated the effects of sildenafil on hemodynamics and signaling molecules in a piglet overcirculation-induced model of early PAH. Methods and Results—Thirty 3-week-old piglets were randomized to placebo or sildenafil therapy 0.75 mg/kg TID after anastomosis of the left subclavian artery to the pulmonary arterial trunk or after a sham operation. Three months later, the animals underwent a hemodynamic evaluation followed by pulmonary tissue sampling for morphometry, immunohistochemistry or radioimmunoassay, and real-time quantitative-polymerase chain reaction. Chronic systemic-to-pulmonary shunting increased pulmonary mRNA for angiopoietin-1, endothelin-1 (ET-1), angiotensin II, inducible nitric oxide synthase, vascular endothelial growth factor, and PDE-5. Pulmonary messenger RNA for BMPR-1A and BMPR-2 decreased. Pulmonary angiotensin II, ET-1, and vascular endothelial growth factor proteins increased. Pulmonary artery pressure increased from 20±2 to 33±1 mm Hg, and arteriolar medial thickness increased by 91%. The expressions of angiopoietin-1, ET-1, and angiotensin II were tightly correlated to pulmonary hypertension. Sildenafil prevented the increase in pulmonary artery pressure, limited the increase in medial thickness to 41%, and corrected associated biological perturbations except for the angiopoietin-1/BMPR-2 pathway, PDE-5, and angiotensin II. Conclusions—Sildenafil partially prevents overcirculation-induced PAH and associated changes in signaling molecules. Angiotensin II, PDE-5, and angiopoietin-1/BMPR-2 signaling may play a dominant role in the early stages of the disease.

Effects of levosimendan on acute pulmonary embolism-induced right ventricular failure.

Objective:Repeated episodes of pulmonary embolism can persistently increase pulmonary arterial pressure and depress right ventricular contractility. We investigated the effects of levosimendan on right ventricular-pulmonary arterial coupling in this model of right ventricular failure. Design:Prospective, controlled, randomized animal study. Setting:University research laboratory. Subjects:Fourteen anesthetized piglets. Interventions:Repeated acute pulmonary embolisms were induced with autologous blood clots to induce persistent right ventricular failure. Animals were randomly assigned to a control or levosimendan group. Levosimendan 20 &mgr;g/kg was administered in 10 mins followed by 0.2 &mgr;g/kg/min or same volumes of isotonic saline. Measurements and Main Results:Pulmonary artery distal resistance and proximal elastance by pressure-flow relationships and vascular impedance were measured. We noted right ventricle contractility by the end-systolic pressure-volume relationship (Ees), pulmonary artery effective elastance by the end-diastolic to end-systolic relationship (Ea), and right ventricular-pulmonary arterial coupling efficiency by the Ees/Ea ratio. The gradual pulmonary artery embolism increased pulmonary artery resistance and elastance, increased Ea from 1.01 ± 0.17 to 5.58 ± 0.37 mm Hg/mL, decreased Ees from 1.75 ± 0.12 to 1.29 ± 0.20 mm Hg/mL, and decreased Ees/Ea from 1.74 ± 0.20 to 0.24 ± 0.09. Compared with placebo, levosimendan decreased pulmonary arterial elastance and characteristic impedance. Right ventricular-pulmonary arterial coupling was restored by both an increase in right ventricular contractility and a decrease in right ventricular afterload. Conclusions:A gradual increase in pulmonary artery pressure induced by pulmonary embolism persistently worsens pulmonary artery hemodynamics, right ventricular contractility, right ventricular-pulmonary arterial coupling, and cardiac output. Levosimendan restores right ventricular-pulmonary arterial coupling better than placebo, because of combined pulmonary vasodilation and increased right ventricular contractility.

Pulse pressure is an independent determinant of renal function decline during treatment of essential hypertension.

Background In large epidemiological studies and using serum creatinine or estimates of glomerular filtration rate (GFR), blood pressure has emerged as a predominant determinant of the age-associated decline in renal function. Methods The present longitudinal study (median follow-up period of 5.8 years) was conducted in 132 never-treated patients with essential hypertension at baseline. The effect of treatment on the GFR and effective renal plasma flow, estimated by urinary clearances of isotopic markers, was assessed. Results Satisfactory control of hypertension (<140/90 mmHg) was achieved in 57% of the population. During follow-up, the yearly change in the GFR was −1.72 ± 0.21 ml/min per year (mean ± SEM). In univariate regression analysis, the change in the GFR was correlated with baseline pulse pressure (r = −0.27, P = 0.002), whereas no influence of systolic, diastolic or mean blood pressures, as well as baseline albuminuria or left ventricular mass index, was found. Multivariate logistic regression analysis showed that only baseline pulse pressure conveyed a significant odds ratio of accelerated decline of GFR (> median of 1.5 ml/min per year), independently of age, baseline GFR, mean blood pressure and other known cardiovascular risk factors. No influence of the type of antihypertensive treatment (64% of the population had received angiotensin-converting enzyme inhibitor) was detected. Conclusion Pulse pressure (a marker of arterial stiffening) is suggested as an independent determinant of the treatment-associated decline in renal function in essential hypertension. No influence of target organ damage (albuminuria of left ventricular hypertrophy) was detected.

Prolonged overcirculation-induced pulmonary arterial hypertension as a cause of right ventricular failure

AIMS Three-month chronic systemic-to-pulmonary shunting in growing piglets has been reported as an early pulmonary arterial hypertension (PAH) model with preserved right ventricular (RV) function. We sought to determine whether prolonged shunting might be associated with more severe PAH and RV failure. METHODS AND RESULTS Fourteen growing piglets were randomized to a sham operation or the anastomosis of the left innominate artery to the pulmonary arterial trunk. Six months later, the shunt was closed and the animals underwent haemodynamic evaluation followed by tissue sampling for pathobiological assessment. Prolonged shunting had resulted in increased mean pulmonary artery pressure (22 ± 2 versus 17 ± 1 mmHg) and pulmonary arteriolar medial thickness, while cardiac output was decreased. However, RV-arterial coupling was markedly deteriorated, with a ~50% decrease in the ratio of end-systolic to pulmonary arterial elastances (Ees/Ea). Lung tissue expressions of endothelin-1, angiopoietin-1, and bone morphogenetic protein receptor-2 were similarly altered compared with previously observed after 3-month shunting. At the RV tissue level, pro-apoptotic ratio of Bax-to-Bcl-2 expressions and caspase-3 activation were increased, along with an increase in cardiomyocyte size, while expressions in voltage-gated potassium channels (Kv1.5 and Kv2.1) and angiogenic factors (angiopoietin-2 and vascular endothelial growth factor) were decreased. Right ventricular expressions of pro-inflammatory cytokines [interleukin (IL)-1α, IL-1β, tumour necrosis factor-α (TNF-α)] and natriuretic peptide precursors (NPPA and NPPB) were increased. There was an inverse correlation between RV Ees/Ea and pro-apoptotic Bax/Bcl-2 ratios. CONCLUSIONS Prolonged left-to-right shunting in piglets does not further aggravate pulmonary vasculopathy, but is a cause of RV failure, which appears related to an activation of apoptosis and inflammation.

Single arterial occlusion to locate resistance in patients with pulmonary hypertension

The purpose of this study was to determine the site of increased resistance using the arterial occlusion technique in patients with severe pulmonary hypertension. Pulmonary vascular resistance was partitioned in arterial and venous components based on double exponential fitting analysis of the pulmonary artery pressure decay curve: after balloon occlusion in 36 patients with pulmonary arterial hypertension (PAH); at baseline and during the inhalation of 20 parts per million of nitric oxide (NO); in four patients with chronic thromboembolic pulmonary hypertension; and in two patients with pulmonary veno-occlusive disease. In the patients with PAH, at baseline, mean pulmonary artery pressure was 56±2 mmHg (mean±se), with an arterial component of resistance of 63±1%. Inhaled NO did not change the partition of resistance. The arterial component of resistance amounted on average to 42% and 77% in the patients with veno‐occlusive disease and the patients with thromboembolic pulmonary hypertension, respectively. However, the partitioning of resistance did not discriminate between these three diagnostic categories. The occlusion technique may help to locate the predominant site of increased resistance in patients with severe pulmonary hypertension, but does not allow for a satisfactory differential diagnosis on an individual basis.

Dietary Sodium, Aldosterone, and Left Ventricular Mass Changes During Long-Term Inhibition of the Renin-Angiotensin System

In essential hypertension, the regression of left ventricular hypertrophy is an important goal of treatment. In addition to treatment-associated changes in blood pressure (BP), the roles of other determinants of left ventricular hypertrophy regression, including dietary sodium intake, deserve investigation. In the present study, the change in echographic left ventricular mass index (LVMI) was assessed in 182 patients with never-treated essential hypertension at baseline and after 3 years of treatment by angiotensin converting enzyme inhibitors or angiotensin II receptor antagonists given at recommended doses and associated with other antihypertensive agents. Treatment was associated with satisfactory control of BP (<140/90 mm Hg) in 64% of patients, and left ventricular hypertrophy prevalence decreased from 56% to 39%. Twenty-four–hour urinary sodium was positively related to LVMI at baseline and at the end of the study, independently of age, sex, and systolic BP. Supine plasma aldosterone concentration was correlated with LVMI only at baseline but not in multivariate analysis. In response to treatment, the percentage of change in LVMI was positively correlated with the absolute changes in systolic BP, urinary sodium, and plasma aldosterone concentration, independently of baseline LVMI. The population was divided into 3 tertiles according to final values of gender-specific urinary sodium. When, within each urinary sodium tertile, patients were divided into those with plasma aldosterone concentration below and above the median (11.6 ng/dL), LVMI progressively increased across sodium tertiles only in patients with high plasma aldosterone concentration. Systolic BP was similar across all of the groups. In conclusion, aldosterone requires the presence of high dietary salt for the expression of its unfavorable effect on the heart.