Bio-Humoral and Non-Invasive Haemodynamic Correlates of Renal Venous Flow Patterns across the Heart Failure Spectrum

Background: We evaluated the bio-humoral and non-invasive haemodynamic correlates of renal congestion evaluated by Doppler renal venous flow (RVF) across the heart failure (HF) spectrum, from asymptomatic subjects with cardiovascular risk factors (Stage A) and structural heart disease (Stage B) to patients with clinically overt HF (Stage C). Methods: Ultrasound evaluation, including echocardiography, lung ultrasound and RVF, along with blood and urine sampling, was performed in 304 patients. Results: Continuous RVF was observed in 230 patients (76%), while discontinuous RVF (dRVF) was observed in 74 (24%): 39 patients had pulsatile RVF, 18 had biphasic RVF and 17 had monophasic RVF. Stage C HF was significantly more common among patients with dRVF. Monophasic RVF was associated with worse renal function and a higher urinary albumin-to-creatinine ratio (uACR). After adjusting for hypertension, diabetes mellitus, the presence of Stage C HF and serum creatinine levels, worsening RVF patterns were associated with higher NT-proBNP levels, worse right ventricular-arterial coupling, larger inferior vena cava and higher echo-derived pulmonary artery wedge pressure. This trend was confirmed when only patients with HF Stage C were analysed after adjusting for the left ventricle ejection fraction (LVEF). Conclusion: Abnormal RVF is common across the HF spectrum. Worsening RVF patterns are independently associated with increased congestion, worse non-invasive haemodynamics and impaired RV-arterial coupling. RVF evaluation could refine prognostic stratification across the HF spectrum, irrespective of LVEF.

Deep phenotype characterization of hypertensive response to exercise: implications on functional capacity and prognosis across the heart failure spectrum

AIMS

Limited evidence is available regarding the role of hypertensive response to exercise (HRE) in heart failure (HF). We evaluated the systolic blood pressure (SBP) to workload slope during exercise across the HF spectrum, investigating haemodynamic and prognostic correlates of HRE.

METHODS AND RESULTS

We prospectively enrolled 369 patients with HF Stage C (143 had preserved [HFpEF], and 226 reduced [HFrEF] ejection fraction), 201 subjects at risk of developing HF (HF Stages A-B), and 58 healthy controls. We performed a combined cardiopulmonary exercise stress echocardiography testing. We defined HRE as the highest sex-specific SBP/workload slope tertile in each HF stage. Median SBP/workload slope was 0.53 mmHg/W (interquartile range 0.36-0.72); the slope was 39% steeper in women than men (p < 0.0001). After adjusting for age and sex, SBP/workload slope in HFrEF (0.47, 0.30-0.63) was similar to controls (0.43, 0.35-0.57) but significantly lower than Stages A-B (0.61, 0.47-0.75) and HFpEF (0.63, 0.42-0.86). Patients with HRE showed significantly lower peak oxygen consumption and peripheral oxygen extraction. After a median follow-up of 16 months, HRE was independently associated with adverse outcomes (all-cause mortality and hospitalization for cardiovascular reasons: hazard ratio 2.05, 95% confidence interval 1.81-5.18), while rest and peak SBP were not. Kaplan-Meier analysis confirmed a worse survival probability in Stages A-B (p = 0.005) and HFpEF (p < 0.001), but not HFrEF.

CONCLUSION

A steeper SBP/workload slope is associated with impaired functional capacity across the HF spectrum and could be a more sensitive predictor of adverse events than absolute SBP values, mainly in patients in Stages A-B and HFpEF.

Very-low-calorie ketogenic diet (VLCKD) in the management of metabolic diseases: systematic review and consensus statement from the Italian Society of Endocrinology (SIE)

BACKGROUND

Weight loss is a milestone in the prevention of chronic diseases associated with high morbility and mortality in industrialized countries. Very-low calorie ketogenic diets (VLCKDs) are increasingly used in clinical practice for weight loss and management of obesity-related comorbidities. Despite evidence on the clinical benefits of VLCKDs is rapidly emerging, some concern still exists about their potential risks and their use in the long-term, due to paucity of clinical studies. Notably, there is an important lack of guidelines on this topic, and the use and implementation of VLCKDs occurs vastly in the absence of clear evidence-based indications.

PURPOSE

We describe here the biochemistry, benefits and risks of VLCKDs, and provide recommendations on the correct use of this therapeutic approach for weight loss and management of metabolic diseases at different stages of life.

Arterial-ventricular coupling and parameters of vascular stiffness in hypertensive patients: Role of gender

Objective

Non-invasive estimation of arterial–ventricular coupling has been extensively used for the evaluation of cardiovascular performance, however, a relative small amount of data is available regarding arterial–ventricular coupling and its components in hypertension. The present study was designed to investigate the relationship between left ventricular elastance, arterial elastance, parameters of vascular stiffness and the influence of gender in a population of hypertensive individuals.

Methods

In 102 patients, trans-thoracic cardiac ultrasound, parameters of aortic stiffness (carotid-femoral pulse wave velocity) and wave reflection (augmentation index) were recorded. Ultrasound images of common carotid arteries were acquired for the assessment of intima-media thickness as well as carotid compliance and distensibility coefficient.

Results

Mean age was 61 years, 32% diabetes, 56% dyslipidemia, 9% previous cardiovascular events; women (n = 32) and men were superimposable for cardiovascular risk factors prevalence. In the population, ventricular elastance was significantly correlated with arterial elastance (r = 0.887), age (r = 0.334), gender (r = −0.494), BMI (r = −0.313), augmentation index (r = 0.479) (all p < 0.001); and with carotid compliance and distensibility coefficient (r = 0.229 and r = − 0.250, respectively, both p < 0.05); however, only arterial elastance and gender were independently associated with ventricular elastance in multiple regression models adjusted for confounding factors. Gender-specific analysis revealed that arterial elastance and augmentation index remained statistically significant associated with ventricular elastance in men (r = 0.275, p = 0.04); instead augmentation index was no longer significant (r = 0.052, p = 0.77) in the female sex.

Conclusions

In hypertensive patients, main determinants of ventricular elastance are arterial elastance, as an integrated index of arterial vascular load, and gender; however, pressure augmentation might play an additional role in men.

Plasma metalloproteinase-9 and restrictive filling pattern as major predictors of outcome in patients with ischemic cardiomyopathy

OBJECTIVE

Assessment of plasma matrix metalloproteinase-9 (MMP-9) and Doppler markers of increased left ventricular (LV) filling pressure may be added to risk stratify patients with ischemic cardiomyopathy (IC). Therefore, we aimed at investigating the value of plasma MMP-9 and restrictive filling pattern (RFP) in IC patients.

METHODS

Eighty-eight consecutive patients hospitalized for heart failure (LV ejection fraction ≤ 40%) due to IC were enrolled. A complete M-mode and two-dimensional echo-Doppler examination were performed. Patients were defined as having RFP if they had a mitral E wave deceleration time<150 ms. Plasma MMP-9 and N-terminal protype-B natriuretic peptide levels were assessed at the time of the index echocardiogram. The end point was all-cause mortality or hospitalization for worsening HF. Follow-up period was 25 ± 17 months.

RESULTS

Median value of MMP-9 was 714 ng/ml. On univariate analysis, a number of measurements predicted the composite end point: NYHA class>2, RFP, MMP-9>60.5 ng/ml, LV ejection fraction<27%, anemia, pulmonary pressure ≥ 35 mm Hg, N-terminal protype-B natriuretic peptide>1742 pg/ml, and glomerular filtration rate<60 ml/min/1.73 m(2). Independent variables of outcome were anemia (HR=1.9, p=0.031), and the combination of plasma MMP-9 and RFP (HR=3.2, p=0.004). On Kaplan-Meier survival curves, patients with elevated MMP-9 levels and RFP had the lowest event-free survival rate (log-rank: 29.0, p<0.0001). The net reclassification improvement showed a significant increase in the prediction model when elevated MMP-9 and RFP were added to the base model that included clinical, biochemical and echocardiographic parameters (p<0.0001).

CONCLUSION

MMP-9 levels and RFP have an incremental predictive value to risk classify IC patients.

Developments in imaging technologies related to hypertensive cardiovascular diseases

This article reviews the current imaging techniques and the methodologies used to derive quantitative markers of hypertension in the cardiovascular system. Firstly, simple but effective methods to assess regional and global function of large arteries are discussed. After, the role of echocardiography and high-resolution magnetic resonance imaging to assess geometric and mechanical indices of hypertension related cardiac diseases are summarized. In particular, quantitative indices of deformation and strain are derived from quantitative analysis of doppler tissue and tagged magnetic resonance images. Finally, the importance of high field magnetic resonance imaging to assess myocardial microcirculation is described.

Speckle-tracking echocardiography: a new technique for assessing myocardial function

Speckle-tracking echocardiography has recently emerged as a quantitative ultrasound technique for accurately evaluating myocardial function by analyzing the motion of speckles identified on routine 2-dimensional sonograms. It provides non-Doppler, angle-independent, and objective quantification of myocardial deformation and left ventricular systolic and diastolic dynamics. By tracking the displacement of the speckles during the cardiac cycle, strain and the strain rate can be rapidly measured offline after adequate image acquisition. Data regarding the feasibility, accuracy, and clinical applications of speckle-tracking echocardiography are rapidly accumulating. This review describes the fundamental concepts of speckle-tracking echocardiography, illustrates how to obtain strain measurements using this technique, and discusses their recognized and developing clinical applications.

[Real-time multiplane echocardiography. Current applications, limits and perspectives]

Echocardiography is the most commonly used imaging technique in current clinical cardiology practice and is usually performed using a monoplane approach. In recent years new matrix-array transducers have become available that allow the real-time simultaneous display of two or more echocardiographic scanning planes from the same acoustic window. This multiplane approach is particularly interesting as it may reduce, during the examination, the number of probe movements and consequently facilitate image acquisition. In some clinical applications, moreover, the multiplane approach improves both accuracy and reproducibility of echocardiography. This review evaluates the state of the art of multiplane echocardiography and discusses possible clinical applications, advantages and limitations of this technique.

[Transthoracic real-time three-dimensional echocardiography: clinical role, value and limitations in assessing heart valves]

The introduction of three-dimensional echocardiography and its evolution from time-consuming and cumbersome off-line reconstruction to real-time volumetric technique (real-time three-dimensional echocardiography) are one of the most significant advances in ultrasound imaging of the heart of the past decade. This imaging modality currently provides realistic views of cardiac valves capable of demonstrating the anatomy of various heart valve diseases in a unique, noninvasive manner. In addition, real-time three-dimensional echocardiography offers completely new views of the valves and surrounding structures, and allows accurate quantification of severity of valve disease. This article reviews the advantages of real-time three-dimensional echocardiography in assessing heart valves and shows also technological limitations in order to provide the scientific basis for its clinical use.

Plasma matrix metalloproteinase-9 better predicts outcome than N-terminal protype-B natriuretic peptide in patients with systolic heart failure and a high prevalence of coronary artery disease

Metalloproteinases have been proposed as biochemical markers of left ventricular (LV) remodeling in systolic heart failure (HF). However, their role in the prognostic stratification of these patients remains controversial. In the present study, we aimed at investigating the value of plasma metalloproteinases-3 and -9 in comparison with N-terminal protype-B natriuretic peptide in patients with systolic HF. One hundred and 27 consecutive patients hospitalized for systolic HF (LV ejection fraction < 45%) were enrolled. Coronary artery disease (CAD) was the aetiology in 67% of the study patients. Plasma metalloproteinases-3 and -9 and N-terminal protype-B natriuretic peptide levels were assessed. A complete echocardiographic and Doppler examination was also performed. Follow-up period was 24-15 months. On univariate analysis, a number of measurements predicted cardiac events in the following order of power: NYHA class >2, LV ejection fraction < 25%, metalloproteinases-9 > 238 ng/ml, mitral E wave deceleration time < 150 ms, N-terminal protype-B natriuretic peptide > 1586 pg/ml and metalloproteinases-3 > 15 ng/ml. However, on multivariate analysis the only independent variables of cardiac events were NYHA class (OR=2.26, p=0.059) and plasma metalloproteinases-9 (OR=2.00, p=0.029). On Kaplan-Meier survival analysis, patients with elevated levels of metalloproteinases-9 exhibited a significantly worse event free-survival at 45 months than those without (21% vs. 54%, log-rank: 13.93, p=0.0002). A worse survival was also observed in patients with elevated N-terminal protype-B natriuretic peptide levels with respect to those without (18% vs. 46%, log-rank: 9.11, p=0.025). Our results demonstrated the value of plasma metalloproteinases-9 levels for prognostication of patients with systolic HF and a high prevalence of CAD.

Echocardiography in patients with hypertrophic cardiomyopathy: usefulness of old and new techniques in the diagnosis and pathophysiological assessment

Hypertrophic cardiomyopathy (HCM) is one of the most common inherited cardiomyopathy. The identification of patients with HCM is sometimes still a challenge. Moreover, the pathophysiology of the disease is complex because of left ventricular hyper-contractile state, diastolic dysfunction, ischemia and obstruction which can be coexistent in the same patient. In this review, we discuss the current and emerging echocardiographic methodology that can help physicians in the correct diagnostic and pathophysiological assessment of patients with HCM.

Circulating matrix metalloproteinase-3 and metalloproteinase-9 and tissue Doppler measures of diastolic dysfunction to risk stratify patients with systolic heart failure

Abnormal matrix metalloproteinase (MMP) activity and diastolic dysfunction may affect left ventricular (LV) remodeling and prognosis, but it is not known whether the combined evaluation of MMP-3 and MMP-9 and variables of diastolic dysfunction are useful for the risk stratification of patients with systolic heart failure (HF). Therefore, this study was designed to assess the value of combining circulating levels of MMPs and tissue Doppler measures of LV diastolic dysfunction to risk-stratify patients with systolic HF. Consecutive patients with systolic HF due to either ischemic or nonischemic cardiomyopathy (n = 134) and LV ejection fractions <45% were submitted to complete echocardiographic and Doppler examinations. The ratio of mitral E peak velocity and averaged e' velocity (E/e') was calculated. Plasma levels of MMP-3 and MMP-9 were measured at the time of index echocardiography. All-cause mortality was defined as the end point. The mean LV ejection fraction was 28 +/- 9%. There was a total of 32 deaths during follow-up (24 +/- 14 months). Several clinical, biochemical, Doppler, and echocardiographic parameters were associated with the outcome on univariate Cox regression analysis. After statistical adjustment for the potentially confounding factors by multivariate analysis, E/e' (hazard ratio 1.11, p = 0.0028), ejection fraction (hazard ratio 0.92, p = 0.017), and MMP-9 (hazard ratio 1.01, p = 0.027) remained significant independent predictors of the end point. Kaplan-Meier curves showed that survival was worse in patients with E/e' ratios >/=13 and MMP-9 levels >89.9 ng/mL (p <0.0001). In conclusion, the assessment of circulating MMP levels and tissue Doppler measures of LV diastolic dysfunction may improve the prognostic stratification of patients with systolic HF.

[B-type natriuretic peptide and Doppler echocardiography in the diagnosis of heart failure: alternative or complementary tools?]

Several studies have demonstrated the usefulness of B-type natriuretic peptide (BNP) dosage in patients referring for acute dyspnea in the emergency department. BNP is strongly associated not only with the evidence but even with the degree of heart failure, and BNP values are particularly increased in the advanced NYHA classes and in patients with poor prognosis. High BNP levels correlate with echocardiographic indexes of left ventricular and right ventricular systolic dysfunction but even better with diastolic dysfunction and degree of left ventricular filling pressure. However, in presence of some clinical confounders, such as obesity, renal insufficiency and anemia, BNP dosage itself cannot be interpretable. Under these circumstances, Doppler echocardiography is able to identify with better accuracy patients affected by heart failure. Algorithms built taking into account clinical and echocardiographic parameters as well as BNP measurements are already available in the guidelines of the European Society of Cardiology on heart failure with normal ejection fraction. They will lead to a better and earlier identification, better risk stratification and management of patients referring for heart failure.

[Echocardiographic evaluation of the athlete's heart: from morphological adaptations to myocardial function]

The definition of the athlete's heart includes the mechanisms of cardiac adaptation to training, characterized by the increase of internal chamber dimensions, ventricular wall thickness, and atrial chambers. The morphology of the athlete's heart is intermediate between concentric and eccentric left ventricular hypertrophy (LVH), in relation to the large prevalence of mixed sports activities and training protocols (including both aerobic and anaerobic exercise). Echocardiography is the tool of choice for the assessment of the athlete's heart and also for the differentiation of physiologic and pathologic LVH (hypertrophic cardiomyopathy and LVH due to arterial hypertension). The initial echocardiographic approach includes the quantitative analysis of the left ventricle, in order to calculate left ventricular mass, left ventricular mass index and relative wall thickness for diagnosing concentric or eccentric LVH. Tissue Doppler (pulsed or color modality) and strain rate imaging (Doppler or two-dimensional modality) may give additional information to the standard indices of systolic function. Diastolic function can be evaluated not only by standard Doppler transmitral inflow measurements but also using pulsed tissue Doppler, which may allow to distinguish the athlete's LVH from diastolic impairment of hypertensive patients or hypertrophic cardiomyopathy by the simple determination of myocardial early diastolic velocity. Also the morphological and functional features of the left atrium and of the right ventricle can be assessed in the athlete's heart by combining standard echocardiography with new echocardiographic technologies.

[Real-time three-dimensional echocardiography: current applications, advantages and limits for the evaluation of the left ventricle]

In the last decades the introduction and development of echocardiography allowed a significant improvement in the diagnosis as well as in the morphological and functional evaluation of several heart diseases, and today many therapeutic decisions are taken based on the results of the echocardiographic examination. One of the most important development in the field of echocardiography is three-dimensional imaging, which has evolved from the slow and labor-intense off-line reconstruction techniques to the faster and simpler real-time volumetric imaging, which has the potential to be integrated in routine clinical practice. One of the major proven advantages of real-time three-dimensional echocardiography is the evaluation of left ventricular volume, mass and function, which is achieved by eliminating the need for geometric modeling and the errors caused by foreshortened views. In this review we discuss the state-of-the-art and anticipate future developments of real-time three-dimensional echocardiography that are relevant to its application to the left ventricle.

Coronary flow reserve in idiopathic dilated cardiomyopathy: relation with left ventricular wall stress, natriuretic peptides, and endothelial dysfunction

Studies have demonstrated impaired coronary blood flow reserve (CBFR) in idiopathic dilated cardiomyopathy (IDCM). It was the aim of this study to examine the potential underlying mechanisms for CBFR reduction in patients with IDCM by Doppler ultrasound techniques. Forty-eight clinically stable patients with heart failure caused by IDCM (New York Heart Association classes 1-3) were evaluated by echocardiographic and Doppler techniques with the assessments of CBFR and brachial artery flow-mediated dilation (FMD). CBFR was estimated as the hyperemic (dipyridamole: 0.84 mg/kg in 10 minutes, intravenously) to resting coronary diastolic peak velocities ratio. N-terminal pro-brain natriuretic peptide (Nt-pro-BNP) plasma levels were measured at the time of the index echocardiogram. Left ventricular (LV) ejection fraction was 30% +/- 8%, and wall motion score index was 2.0 +/- 0.25. The best correlation with CBFR was found with LV wall thickness-to-cavity radius (r = 0.77, P < .0001). A strong correlation of log-transformed Nt-pro-BNP levels was observed with CBFR (r = -0.64; P < .0001). No significant correlation was documented between CBFR and FMD. The stepwise regression model showed that LV wall thickness-to-cavity radius was the strongest independent predictor of CBFR followed by New York Heart Association class and log-transformed Nt-pro-BNP leading to a cumulative R value of 0.82 (P < .0001). The results of the study indicate that by measuring variables related to LV end-diastolic wall stress, such as LV wall thickness-to-cavity radius and plasma Nt-proBNP, it is possible to have information about CBFR in patients with heart failure secondary to IDCM.

Treatment with low doses of cabergoline is not associated with increased prevalence of cardiac valve regurgitation in patients with hyperprolactinaemia

INTRODUCTION AND AIM

Dopamine agonists have been reported to increase the risk of cardiac valve regurgitation in patients with Parkinson's disease. However, it is unknown whether these drugs might be harmful for patients with hyperprolactinaemia (HyperPRL). The aim of the study was to evaluate whether HyperPRL patients treated with dopamine agonists had a higher prevalence of cardiac valves regurgitation than that of general population.

METHODS AND PATIENTS

One hundred consecutive patients (79 women, 21 men, mean age 41 +/- 13 years) with HyperPRL during treatment with cabergoline were enrolled in an observational case-control study and compared with 100 matched normal subjects (controls). Valve regurgitation was assessed by echocardiography according to the American Society of Echocardiography recommendations.

RESULTS

Seven HyperPRL patients (7%) and six controls (6%) had moderate (grade 3) regurgitation in any valve (p = 0.980). All were asymptomatic and had no signs of cardiac disease. Mean duration of cabergoline treatment was 67 +/- 39 months (range: 3-199 months). Mean cumulative dose of cabergoline was 279 +/- 301 mg (range: 15-1327 mg). Moderate valve regurgitation was not associated with the duration of treatment (p = 0.359), with cumulative dose of cabergoline (p = 0.173), with age (p = 0.281), with previous treatment with bromocriptine (p = 0.673) or previous adenomectomy (p = 0.497) in patients with HyperPRL.

DISCUSSION

In conclusion, treatment with cabergoline was not associated with increased prevalence of cardiac valves regurgitation in patients with HyperPRL. Mean cumulative dose of cabergoline was lower in patients with HyperPRL than that reported to be deleterious for patients with Parkinson's disease: hence, longer follow-up is necessary, particularly in patients receiving weekly doses > 3 mg.

[Principles of cardiovascular dynamics in the perspective of echocardiography]

The possibilities of applying the laws of dynamics to the study of myocardial mechanics are remarkable and to some extent neglected to characterize ventricular performance by the imaging techniques. There are potentially useful applications derived from the analyses of Doppler flow velocity profiles of left ventricular outflow to be applied to the study of cardiovascular dynamics. They include ejection force, pressure-volume work and ventricular power. All these variables require measurements that are easy to obtain even during a standard examination, like stroke volume, ventricular outflow velocity, and the velocity-time integral.

N-terminal protype-B natriuretic peptide and Doppler diastolic variables are incremental for risk stratification of patients with NYHA class I-II systolic heart failure

BACKGROUND

In systolic heart failure (HF), preventing the development of severe symptoms, before patients are in advanced NYHA functional classes, is a worthwhile target of therapy. Early recognition of left ventricular (LV) diastolic dysfunction and neuroendocrine activation may have an important impact on patient's outcome.

AIM

To investigate whether N-terminal proBNP (NT-proBNP) and mitral flow and tissue Doppler (TD) diastolic parameters are incremental for risk stratification of systolic HF patients in NYHA class I and II.

METHODS

The study consisted of 232 consecutive outpatients with systolic HF (ejection fraction [EF] <or=45%) in NYHA class I to II. They had a full Doppler two-dimensional-echocardiographic study, including pulsed-Doppler mitral E wave deceleration time (EDT) and TD early septal annular velocity (E'). Plasma NT-proBNP was assessed at the time of the echocardiogram.

RESULTS

During a median follow-up of 31 months, there were 65 events (25 deaths and 40 HF-related hospitalizations). Multivariate analysis showed that N-terminal proBNP >544 pg/ml (hazards ratio [HR]: 2.66; p=0.012), EF <37% (HR: 2.45; p=0.006), E <or=8 cm/s (HR: 1.84; p=0.045) and EDT <150 ms (HR: 1.78; p=0.026) significantly correlated with events. On forward stepwise analysis, EDT (p<0.0001) and E' (p<0.0001) provided an incremental contribution to the outcome prediction above and beyond conventional risk markers, that was further increased by the addition of NT-proBNP (p<0.0001).

CONCLUSION

In patients with systolic HF in NYHA functional class I and II, N-terminal proBNP and LV mitral flow and TD variables of diastolic dysfunction had a strong predictive power for the combined end point of all-cause mortality and HF-related hospitalizations.

Reduced left ventricular functional reserve in hypertensive patients with preserved function at rest

In many hypertensive patients, left ventricular pump function is normal at rest but abnormal during exercise. Myocardial dysfunction or altered left ventricular loading may be responsible for this finding. To verify the hypothesis of impaired myocardial functional reserve in the hypertensive heart, we assessed the response of stress-adjusted midwall shortening to graded, low-dose dobutamine infusion in hypertensive subjects with normal midwall shortening at rest. Sixty-five subjects (45 never treated hypertensive subjects and 20 normotensive volunteers comparable for age) received dobutamine at 1, 2, 3, 4, and 5 microg x kg(-1) x min(-1) for 5-minute steps; within this range of infusion rates, heart rate and systemic blood pressure were stable. Two-dimensional, M-mode, and Doppler echocardiography were performed at baseline and at the end of each step. In normotensive controls, midwall shortening increased from baseline during 2 microg x kg(-1) x min(-1) dobutamine by an average of 16+/-4.5% (P<0.01); a value of 2 standard deviations below this mean response was taken as the lower limit of normal. In the hypertensive subjects, 24 had a normal midwall shortening response to dobutamine at this dose (group I) and 21 had a subnormal response (group II). Whereas blood pressure and left ventricular mass were similar in group II and group I, the former had greater relative wall thickness (P<0.01) than the latter. beta-adrenergic stimulation by very-low-dose dobutamine unmasks subtle impairment of myocardial functional reserve in hypertensive subjects with normal myocardial performance at rest. This alteration seems to be related mainly to increase in left ventricular relative wall thickness.

Myocardial ultrasonic backscatter in hypertension: relation to aldosterone and endothelin

A disproportionate accumulation of fibrillar collagen is a characteristic feature of hypertensive heart disease, but the extent of myocardial fibrosis may differ in different models of hypertension. In experimental studies, aldosterone and endothelins emerge as important determinants of myocardial fibrosis. Changes in myocardial extracellular matrix and collagen deposition can be estimated noninvasively by analysis of the ultrasonic backscatter signal, which arises from tissue heterogeneity within the myocardium and describes myocardial texture. This study was designed to investigate the relations between myocardial integrated backscatter and circulating aldosterone and immunoreactive endothelin in human hypertension. The study population consisted of 56 subjects: 14 healthy normotensive volunteers and 42 hypertensive patients (14 with primary aldosteronism, 7 with renovascular hypertension, and 21 with essential hypertension). The patients with essential and secondary hypertension were matched for age, gender, body mass index, and blood pressure. Myocardial integrated backscatter at diastole was 19.8+/-2.0 and 20.8+/-2.9 decibels in normotensive control subjects and patients with essential hypertension and significantly higher in patients with primary aldosteronism (27.4+/-3.8 decibels, P<0.01) and renovascular hypertension (26.8+/-4.8 decibels, P<0.01). In the population as a whole, as well as in the hypertensive subpopulation, myocardial integrated backscatter was directly related to plasma aldosterone (r=0.73 and 0.71, P<0.01 for both) and immunoreactive endothelin (r=0.60 and 0.56, P<0.01 for both). The data of this study suggest that in human hypertension, circulating aldosterone and immunoreactive endothelin may induce alterations in left ventricular myocardial texture, possibly related to increased myocardial collagen content.

Ventricular repolarization is prolonged in nondipper hypertensive patients: role of left ventricular hypertrophy and autonomic dysfunction

OBJECTIVE

The aim of this study was to investigate the influence of circadian behavior of blood pressure, left ventricular hypertrophy, and autonomic function on QTc interval duration in untreated hypertensive patients.

DESIGN

Hypertensive patients underwent simultaneous blood pressure and ECG 24-h ambulatory monitoring. Patients were classified into two groups on the basis of a lack of nocturnal fall in blood pressure, as dippers and nondippers. A group of normotensive healthy subjects was studied as controls.

METHODS

QT and QTc intervals were automatically computed and spectral analysis was applied to RR interval time series from the same electrocardiogram (ECG) recordings. Left ventricular mass index (LVMI) was computed by echocardiogram.

RESULTS

No difference among the three groups was found concerning mean values and circadian pattern of heart rate; by contrast, QTc was significantly longer in nondippers compared to dippers or to normotensive subjects, particularly at night-time, whereas all groups exhibited similar circadian variations in heart rate. Compared to dippers, nondippers showed significantly higher LVMI, which positively correlated with QTc, and parasympathetic withdrawal, which negatively correlated with QTc.

CONCLUSIONS

Nondippers show a prolonged ventricular repolarization throughout the 24-h period, absent either in dippers or normotensives. The association of left ventricular hypertrophy and vagal deactivation may lead to prolongation of QTc, potentially facilitating ventricular arrhythmias in nondipper hypertensive patients.

Endothelial function in hypertension: role of gender

Endothelium plays an important role in the modulation of vascular tone and structure mainly through the production of nitric oxide (NO), which causes local vasodilation and counteracts processes leading to atherothrombosis. A dysfunctioning endothelium, characterized by reduced NO availability owing to impairment of the L-arginine-NO pathway and, above all, to production of oxygen free radicals, can impair local vasomotion and promote the development of atherosclerosis and of atherothrombotic vascular events. Aging is associated with endothelial dysfunction both in normotensive subjects and in hypertensive patients, and hypertension seems to induce earlier onset of those mechanisms (i.e. impairment of the L-arginine-NO pathway and oxidative stress) that cause age-related endothelial dysfunction. Premenopausal normotensive women are protected against the deleterious effect of aging on endothelial function, and age-related impairment of endothelial function is attenuated in premenopausal hypertensive women. This protective effect on endothelial function seems to be mediated by endogenous estrogen, which preserves NO availability by activating the L-arginine-NO pathway in normotensive women and, again, by activating this pathway but above all by inhibiting oxidative stress in hypertensive women. Thus, the protective effect of endogenous estrogen on endothelial function could be a plausible mechanism contributing to the lower cardiovascular risk of premenopausal women. Finally, whether endogenous androgen can impair endothelial function is still an unsolved issue since data concerning the effect of testosterone on endothelial function are scanty and contradictory.

[Echocardiography in the non-invasive evaluation of coronary reserve and myocardial perfusion in arterial hypertension]

Systemic hypertension is associated with structural and functional alterations of the coronary circulation, which increase the susceptibility of the hypertensive heart to myocardial ischemia. The spectrum of modifications in the coronary macro and microcirculation of the hypertensive heart is relatively wide, and their assessment requires advanced and possibly non-invasive diagnostic approaches. This paper describes the possibility and the additive value of myocardial contrast echocardiography and of coronary velocimetry by Doppler echocardiography for the assessment of coronary function in hypertensive subjects.

Effect of acute blood pressure reduction on endothelial function in the brachial artery of patients with essential hypertension

OBJECTIVES

To evaluate the effect of acute blood pressure reduction on endothelium-dependent vasodilation in the peripheral circulation of essential hypertensive patients.

DESIGN

A parallel group study; endothelial function measured in 64 essential hypertensive patients before and after (2 h) treatment with nifedipine (20 mg, n = 32) or captopril (50 mg, n = 32), p.o., randomly assigned.

METHODS

In hypertensive patients, we evaluated flow-mediated, endothelium-dependent dilation (FMD, high resolution ultrasound) of the brachial artery compared with endothelium-independent response to glyceryl trinitrate (GTN, 25 microg s.l.). Automatic computerized analysis was used to measure brachial artery diameter on end-diastolic frames acquired every second during the study. Sixty-six healthy normotensive subjects were also evaluated to assess the presence of endothelial dysfunction in hypertensive patients.

RESULTS

Hypertensive patients showed a significantly (P< 0.01) lower FMD (5.9 +/- 2.5%) as compared to healthy controls (7.7 +/- 3.8%). The response to GTN was similar in normotensive subjects (7.5 +/- 3.1%) and hypertensive patients (7.2 +/- 6.5%). At baseline brachial artery diameter, FMD and response to GTN were similar in the nifedipine- and captopril-treated groups. Nifedipine and captopril similarly reduced blood pressure, but only nifedipine increased heart rate. Acute nifedipine, but not captopril, significantly (P< 0.01) increased brachial artery diameter, while FMD and response to GTN were not modified after nifedipine or captopril.

CONCLUSIONS

Endothelial dysfunction in the brachial artery of essential hypertensive patients is not improved by acute blood pressure reduction.

Mechanisms responsible for endothelial dysfunction associated with acute estrogen deprivation in normotensive women

BACKGROUND

The goal of this study was to evaluate whether endothelial dysfunction associated with acute estrogen deprivation is caused by an alteration in the L-arginine-nitric oxide (NO) pathway and oxidative stress. Methods and Results-In 26 healthy women (age, 45.7+/-5.4 years) and 18 fertile women with leiomyoma (age, 44.5+/-5.1 years), we studied forearm blood flow (strain-gauge plethysmography) changes induced by intrabrachial acetylcholine (0. 15, 0.45, 1.5, 4.5, or 15 microgram. 100 mL(-1). min(-1)) or sodium nitroprusside (1, 2, or 4 microgram. 100 mL(-1). min(-1)), an endothelium-dependent or -independent vasodilator, respectively. The NO pathway was evaluated by repeating acetylcholine during L-arginine (200 microgram. 100 mL(-1). min(-1); 13 control subjects and 9 patients) or N(G)-monomethyl-L-arginine (L-NMMA; 100 microgram. 100 mL(-1). min(-1); 13 control subjects and 9 patients); production of cyclooxygenase-derived vasoconstrictors was assessed by repeating acetylcholine during indomethacin (50 microgram. 100 mL(-1). min(-1); 13 control subjects and 9 patients) or vitamin C (8 mg. 100 mL(-1). min(-1); 13 control subjects and 9 patients). Patients repeated the study within 1 month after ovariectomy and again after 3 months of estrogen replacement therapy (ERT; 17 beta-estradiol TTS, 50 microgram/d). Basally, vasodilation to acetylcholine was potentiated and inhibited by L-arginine and L-NMMA, respectively (P<0.05), but was unaffected by indomethacin or vitamin C. After ovariectomy, the modulating effect of L-arginine and L-NMMA disappeared, whereas indomethacin and vitamin C potentiated the response to acetylcholine (P<0.05). ERT restored L-arginine and L-NMMA effects on vasodilation to acetylcholine but prevented the potentiation caused by indomethacin or vitamin C. Response to sodium nitroprusside was unaffected by either ovariectomy or ERT.

CONCLUSIONS

Endothelial dysfunction secondary to acute endogenous estrogen deprivation is caused by reduced NO availability. Cyclooxygenase-dependent production of oxidative stress could be responsible for this alteration.

Vasodilation to bradykinin is mediated by an ouabain-sensitive pathway as a compensatory mechanism for impaired nitric oxide availability in essential hypertensive patients

BACKGROUND

In essential hypertension, endothelium-dependent vasodilation is impaired because of reduced nitric oxide (NO) availability, which is mainly caused by oxidative stress. The present study was designed to identify the mechanism(s) responsible for NO-independent vasodilation to bradykinin in patients with essential hypertension.

METHODS AND RESULTS

In 16 healthy subjects (49.5+/-5.8 years; 118.6+/-3.5/78.9+/-2.9 mm Hg) and 16 patients with essential hypertension (47.9+/-4.8 years; 154.6+/-4.5/102.9+/-3.2 mm Hg), we measured modifications in forearm blood flow (strain-gauge plethysmography) during intrabrachial infusion of bradykinin (5, 15, or 50 ng/100 mL of forearm tissue per minute) in the presence of saline, N(omega)-monomethyl-L-arginine (L-NMMA; used to inhibit NO synthase; 100 microg/100 mL of forearm tissue per minute), and ouabain (to block Na(+)K(+)/ATPase and prevent hyperpolarization; 0.7 microg/100 mL of forearm tissue per minute). In healthy subjects, vasodilatation to bradykinin was significantly blunted by L-NMMA and unaffected by ouabain. In hypertensive patients, vasodilatation to bradykinin was not modified by L-NMMA, but it was significantly reduced by ouabain. In an adjunctive group of 8 hypertensive patients (49.9+/-3.8 years; 155.9+/-5.5/103.7+/-3.9 mm Hg), the response to bradykinin was repeated during the administration of intrabrachial vitamin C (a scavenger for oxygen free radicals; 8 mg/100 mL of forearm tissue per minute). In these patients, L-NMMA-induced inhibition of vasodilation to bradykinin was restored, and ouabain was no longer effective. In a final group of 6 normotensive controls (45.9+/-4.1 years; 115.1+/-2.9/79.3+/-2.1 mm Hg), vasodilation to bradykinin residual to L-NMMA blockade was further inhibited by simultaneous ouabain infusion.

CONCLUSIONS

Vasodilation to bradykinin is impaired in essential hypertensive patients because of an NO-system alteration caused by oxidative stress, and it is mediated by an alternative pathway, possibly involving endothelium-dependent hyperpolarization.

Tumor targeting by intra-arterial infusion of 5-[123I]iodo-2'-deoxyuridine in patients with liver metastases from colorectal cancer

We previously showed the tumor-targeting potential of the 125I-labeled thymidine analog 5-iodo-2'-deoxyuridine (IUdR) injected intratumorally in patients with high tumor-cell kinetics. In this study, we evaluated the tumor incorporation of [123I]IUdR infused intra-arterially in patients with liver metastases from colorectal cancer.

METHODS

Iodine-123-IUdR (110-300 MBq, 3-8 mCi, specific activity, 150-200 Ci/mumole) was infused into the hepatic artery of 16 patients with inoperable liver metastases over 30-45 min through a permanent intra-arterial catheter. A dynamic sequence during infusion, spot images, whole-body scans and SPECT acquisitions were recorded up to 42 hr. Blood and urine samples were obtained for biodistribution and HPLC analyses.

RESULTS

In the 14 patients with adequate tumor perfusion patterns, tumor uptake reached 2%-17.6% ID at the end of infusion. After a washout phase that lasted 18-20 hr, incorporated radioactivity remained steadily associated with the tumor lesions until at least 42 hr after infusion (about 1.4%-11.1% ID). HPLC analysis indicated a virtually 100% first-pass hepatic deiodination of unincorporated [123I]IUdR (about 80%-95% ID recovered in the 42-hr urine). No significant uptake was detected in the bone marrow or in other normal dividing tissues.

CONCLUSION

These results encourage further studies to enable dosimetric estimates, optimization of dose regimens, and examination of the therapeutic potential of Auger-electron-emitter-labeled IUdR in cancer therapy utilizing this type of approach.

Tumor uptake and mitotic activity pattern of 5-[125I]iodo-2'- deoxyuridine after intravesical infusion in patients with bladder cancer

In patients with bladder cancer, little is known about diffusion in the tumor mass of 5-iodo-2'-deoxyuridine (IUdR) administered intraluminally, although previous studies based on external scanning have shown promising tumor-targeting properties of IUdR instilled intravesically. This study compared the pattern of IUdR uptake by bladder cancer cells with the actual distribution of mitotic activity, as evaluated by incubation of ex vivo tumor specimens with tritiated thymidine.

METHODS

The [125I]IUdR (2-13 MBq) was instilled over 1-3 hr in the bladder of four patients with bladder cancer scheduled for ablative surgery. Twenty-four hours later, surgical samples were assayed for radioactivity and processed for microautoradiography, while fresh tumor specimens were fragmented, incubated with [3H]thymidine and further processed for microautoradiography. The diffusion of labeled IUdR across the bladder wall was evaluated by blood sampling.

RESULTS

Tumor incorporation of [125I]IUdR 24 hr after intravesical instillation was 0.002%-0.05% ID/g, while the average tumor-to-normal bladder ratio was about 20. Microautoradiography showed that [125I]IUdR incorporation was confined to tumor cells in the most superficial layers of the bladder, while incubation of the tumor fragments with [3H]thymidine demonstrated the presence of diffuse mitotic activity also in the deeper tumor mass. Diffusion of labeled IUdR in the general circulation was minimal.

CONCLUSION

Poor diffusion in the tumor mass makes *IUdR unsuitable for intracavitary therapy of bladder cancer, but the role of such an approach in the postsurgical "sterilization" of cancer remnants floating in the bladder lumen after partial cystectomy should be explored.

Biochemical modulation by 5-fluorouracil and 1-folinic acid of tumor uptake of intra-arterial 5-[123I]iodo-2'deoxyuridine in patients with liver metastases from colorectal cancer

In previous studies we demonstrated a high tumor-targeting value of the 123I-labeled thymidine analogue 5-iodo-2'-deoxyuridine (IUdR) infused intra-arterially in patients with liver metastases from colorectal cancer. In the present study we have explored the possibility of enhancing tumor uptake of [123I]IUdR, by biochemical modulation with 5-fluorouracil (5-FU) and 1-folinic acid (FA), a drug combination known to inhibit thymidylate synthetase in tumor cells. The investigation was carried out employing diagnostic imaging doses of [123I]IUdR, much lower than possible therapeutic levels. In the baseline study, [123I]IUdR was infused into the hepatic artery of patients with inoperable liver metastases from colorectal cancer, and a second infusion was performed one week later, after intra-arterial administration of 5-FU and FA. The effect was evaluated by comparing tumor uptake of [123I]IUdR in the second study with that of the baseline study. The average tumor uptake immediately after [123I]IUdR infusion was 9.1% ID in the baseline study, increasing to 14.9% ID after pretreatment with 5-FU and FA. The average enhancement in early tumor uptake of [123I]IUdR induced by biochemical modulation was 72%. This enhancement was sustained at 18 and 42 hours after infusion (stable uptake). The results encourage the pretreatment of patients with 5-FU and FA prior to radioiodinated IUdR administration and suggest its inclusion in therapeutic protocols employing IUdR labeled with 123I or 125I as a source of highly cytotoxic Auger electrons.