Peripheral vascular remodeling in chronic heart failure: clinical relevance and new conceptualization of its mechanisms

A Rare Case of Bicalutamide-Induced Severe Congestive Heart Failure in a Patient With Advanced Prostate Cancer

Bicalutamide, a nonsteroidal androgen receptor inhibitor, is an established therapeutic agent for advanced prostate cancer but is associated with severe cardiovascular side effects in rare cases. This case report discusses a rare occurrence of severe systolic congestive heart failure (CHF) in a 68-year-old male undergoing treatment for advanced prostate cancer with bicalutamide, without concurrent use of gonadotropin-releasing hormone antagonists. The patient presented with non-specific abdominal and bilateral foot pain. The initial assessment indicated anemia and severe dyspnea, revealing a significant decrease in left ventricular ejection fraction (LVEF) from 55% to 15% on transthoracic echocardiography (TTE), indicative of severe CHF. Bicalutamide was identified as the likely culprit given the temporal association and lack of other identifiable causes, leading to its discontinuation and initiation of guideline-directed medical therapy (GDMT). A remarkable recovery of cardiac function was subsequently observed, with LVEF improving to 60%. The patient was managed with GDMT, and a gonadotropin-releasing hormone antagonist, degarelix, was later introduced for prostate cancer treatment, along with ongoing cardiac monitoring. The recovery of LVEF and the absence of other etiologies reinforce the likelihood of bicalutamide-induced cardiotoxicity. This report underscores the importance of vigilant cardiovascular monitoring in patients receiving bicalutamide, prompt identification of cardiac dysfunction and possible mechanisms of bicalutamide cardiotoxicity, and the potential for cardiac recovery upon drug discontinuation and initiation of GDMT.

Tracking Peripheral Artery Motion and Vascular Resistance with a Multi-Modal Wearable Sensor Under Pressure Perturbations

Peripheral artery status is a key physiological indicator of the body's cardiovascular response to both acute and chronic medical conditions. In this paper, peripheral artery behavior is tracked non-invasively by combining a photo plethysmograph (PPG) sensor and a piezoelectric (polyvinylidene difluoride, PVDF) sensor, while applying an outside pressure-varying cuff. A simple mechanical model for the local artery and tissue captures time- and pressure-dependent features present in the PPG and PVDF signals with respect to applied cuff pressure, during maneuvers applied to multiple swine subjects to perturb blood pressure and vascular resistance. These behaviors provide insight into feasibility and robustness of cardiovascular property identification by multi-modal non-invasive wearable sensing. This is found to help refine non-invasive blood pressure measurements and estimation of systemic vascular resistance (SVR) and blood pressure (BP) using selected features of sensor amplitude versus applied cuff pressure.

Intra-Aortic Balloon Pumping in Acute Decompensated Heart Failure With Hypoperfusion: From Pathophysiology to Clinical Practice

Trials on intra-aortic balloon pump (IABP) use in cardiogenic shock related to acute myocardial infarction have shown disappointing results. The role of IABP in cardiogenic shock treatment remains unclear, and new (potentially more potent) mechanical circulatory supports with arguably larger device profile are emerging. A reappraisal of the physiological premises of intra-aortic counterpulsation may underpin the rationale to maintain IABP as a valuable therapeutic option for patients with acute decompensated heart failure and tissue hypoperfusion. Several pathophysiological features differ between myocardial infarction- and acute decompensated heart failure-related hypoperfusion, encompassing cardiogenic shock severity, filling status, systemic vascular resistances rise, and adaptation to chronic (if preexisting) left ventricular dysfunction. IABP combines a more substantial effect on left ventricular afterload with a modest increase in cardiac output and would therefore be most suitable in clinical scenarios characterized by a disproportionate increase in afterload without profound hemodynamic compromise. The acute decompensated heart failure syndrome is characterized by exquisite afterload-sensitivity of cardiac output and may be an ideal setting for counterpulsation. Several hemodynamic variables have been shown to predict response to IABP within this scenario, potentially guiding appropriate patient selection. Finally, acute decompensated heart failure with hypoperfusion may frequently represent an end stage in the heart failure history: IABP may provide sufficient hemodynamic support and prompt end-organ function recovery in view of more definitive heart replacement therapies while preserving ambulation when used with a transaxillary approach.

Effects of a Short-Term Left Ventricular Assist Device on Hemodynamics in a Heart Failure Patient-Specific Aorta Model: A CFD Study

Patients with heart failure (HF) or undergoing cardiogenic shock and percutaneous coronary intervention require short-term cardiac support. Short-term cardiac support using a left ventricular assist device (LVAD) alters the pressure and flows of the vasculature by enhancing perfusion and improving the hemodynamic performance for the HF patients. However, due to the position of the inflow and outflow of the LVAD, the local hemodynamics within the aorta is altered with the LVAD support. Specifically, blood velocity, wall shear stress, and pressure difference are altered within the aorta. In this study, computational fluid dynamics (CFD) was used to elucidate the effects of a short-term LVAD for hemodynamic performance in a patient-specific aorta model. The three-dimensional (3D) geometric models of a patient-specific aorta and a short-term LVAD, Impella CP, were created. Velocity, wall shear stress, and pressure difference in the patient-specific aorta model with the Impella CP assistance were calculated and compared with the baseline values of the aorta without Impella CP support. Impella CP support augmented cardiac output, blood velocity, wall shear stress, and pressure difference in the aorta. The proposed CFD study could analyze the quantitative changes in the important hemodynamic parameters while considering the effects of Impella CP, and provide a scientific basis for further predicting and assessing the effects of these hemodynamic signals on the aorta.

Free-of-Acrylamide SDS-based Tissue Clearing (FASTClear) for three dimensional visualization of myocardial tissue

Several pathologic conditions of the heart lead to cardiac structural remodelling. Given the high density and the opaque nature of the myocardium, deep three dimensional (3D) imaging is difficult to achieve and structural analysis of pathological myocardial structure is often limited to two dimensional images and of thin myocardial sections. Efficient methods to obtain optical clearing of the tissue for 3D visualisation are therefore needed. Here we describe a rapid, simple and versatile Free-of-Acrylamide SDS-based Tissue Clearing (FASTClear) protocol specifically designed for cardiac tissue. With this method 3D information regarding collagen content, collagen localization and distribution could be easily obtained across a whole 300 µm-thick myocardial slice. FASTClear does not induce structural or microstructural distortion and it can be combined with immunostaining to identify the micro- and macrovascular networks. In summary, we have obtained decolorized myocardial tissue suitable for high resolution 3D imaging, with implications for the study of complex cardiac tissue structure and its changes during pathology.

Bicalutamide causes heart failure in an elderly patient with prostate cancer

OBJECTIVE

To examine the molecular mechanisms by which bicalutamide may cause heart failure in an elderly patient.

METHODS

Retrospective analysis of bicalutamide as a cause of heart failure in Mr FD, an 82 years old with prostate cancer.

RESULTS

Following months of therapy, Mr FD was diagnosed with heart failure. Bicalutamide has been ceased, but 21 months later, Mr FD was still on heart failure medications, and passed away months later probably due to complications of prostate cancer. The Naranjo ADR probability scale gave this case a score of seven.

CONCLUSION

The Naranjo scale strongly suggests that bicalutamide was the cause of heart failure. Apoptosis seems to be one of the mechanisms mediating heart failure, with the involvement of many molecular actors, such as ET-1, Bcl-2 and cyclin-A. The author believes this to be the first analysis describing bicalutamide as a probable cause of heart failure.

Emerging Novel Therapies for Heart Failure

Heart function fails when the organ is unable to pump blood at a rate proportional to the body’s need for oxygen or when this function leads to elevated cardiac chamber filling pressures (cardiogenic pulmonary edema). Despite our sophisticated knowledge of heart failure, even so-called ejection fraction-preserved heart failure has high rates of mortality and morbidity. So, novel therapies are sorely needed. This review discusses current standard therapies for heart failure and launches an exploration into emerging novel treatments on the heels of recently-approved sacubitril and ivbradine. For example, Vasoactive Intestinal Peptide (VIP) is protective of the heart, so in the absence of VIP, VIP knockout mice have dysregulation in key heart failure genes: 1) Force Generation and Propagation; 2) Energy Production and Regulation; 3) Ca⁺² Cycling; 4) Transcriptional Regulators. VIP administration leads to coronary dilation in human subjects. In heart failure patients, VIP levels are elevated as a plausible endogenous protective effect. With the development of elastin polymers to stabilize VIP and prevent its degradation, VIP may therefore have a chance to satisfy the unmet need as a potential treatment for acute heart failure.

Nonphysiologic blood flow triggers endothelial and arterial remodeling in vivo: implications for novel left ventricular assist devices with a peripheral anastomosis

OBJECTIVES

Less invasive circulatory support devices have been developed that require anastomosis to a peripheral artery. The Symphony Heart Assist System (Abiomed, Inc, Danvers, Mass) is a volume-displacement pump sewn to the subclavian artery to provide partial circulatory support. The surgical configuration produces nonphysiologic blood pressure and bidirectional flow in the subclavian artery. Our objective was to identify effects of altered hemodynamics on arterial structure and function.

METHODS

In calves (n = 23; 80-100 kg), the Symphony pump was sewn end-to-side to the carotid artery. Acutely, carotid blood pressure and flow were recorded to evaluate hemodynamic changes. After medium-term support (1-4 weeks), carotid artery was studied. Histologic and molecular assays evaluated architectural changes. Quantitative real-time polymerase chain reaction evaluated gene expression of matrix metalloproteinase (MMP)-2, MMP-9, and connective tissue growth factor. In vitro carotid arterial-ring studies evaluated physiologic responses.

RESULTS

During Symphony support, carotid arterial pressure was 200/15 mm Hg. Antegrade flow increased significantly (P < .05) from 1.40 ± 0.32 to 4.29 ± 0.33 L/min. Flow during native cardiac diastole reversed completely from 0.25 ± 0.05 to -4.15 ± 0.38 L/min in carotid artery proximal to the anastomosis. After medium-term support, the carotid artery was significantly dilated with significantly thinner tunica media and thicker tunica adventitia than in control carotid arteries. MMP-9 gene expression decreased significantly, connective tissue growth factor gene expression increased significantly, and collagen, elastin, and total extracellular matrix increased significantly. Endothelial cells were significantly hypertrophied and produced significantly more von Willebrand factor. Endothelial apoptosis increased significantly. Platelet-endothelial interactions decreased significantly. Endothelial-independent contraction decreased significantly, whereas endothelial-dependent relaxation increased modestly.

CONCLUSIONS

Assisted circulation with a left ventricular assist device triggered arterial remodeling that allowed a peripheral artery to accommodate the altered hemodynamics of a novel partial-support pump. Further delineation of remodeling pathways may be of significance for the emerging field of partial circulatory support.

Endothelial dysfunction is a marker of systemic response to the cardiac resynchronization therapy in heart failure

BACKGROUND

Cardiac resynchronization therapy (CRT) induces a significant improvement in patients with heart failure (HF), who are often characterized by the presence of endothelial dysfunction (ED) with impaired flow-mediated vasodilation (FMD). We aimed to study the ED in patients with HF candidates to CRT with defibrillator (CRT-D).

METHODS AND RESULTS

We studied 57 consecutive patients affected by HF and undergoing CRT-D. At the baseline we recorded a high prevalence of ED (64.9%) with impaired FMD (4.1 ± 3.8%). After 12 months of CRT, we reported a marked increase of the mean FMD (8.8 ± 4.8% vs 4.1 ± 3.8%; P < .05) along with significant improvement of left ventricular ejection fraction (LVEF), left ventricular end-systolic volume (LVESV), New York Heart Association (NYHA) functional class, and 6-minute walk test (6MWT); 42 patients (73.7%) were classified as responders according to standard criteria. FMD was related to LVEF (r = 0.169; P < .05), LVESV (r = -0.169; P < .05), NYHA functional class (r = -0.27; P < .051), and 6MWT (r = 0.360; P < .01).

CONCLUSIONS

ED is not an independent predictor of CRT response, but it is able to intercept the systemic effects of CRT and is an affordable marker of response to CRT, especially in patients unable to perform the 6MWT.

Endothelial Function as a Possible Significant Determinant of Cardiac Function during Exercise in Patients with Structural Heart Disease

This study was investigated the role that endothelial function and systemic vascular resistance (SVR) play in determining cardiac function reserve during exercise by a new ambulatory radionuclide monitoring system (VEST) in patients with heart disease. The study population consisted of 32 patients. The patients had cardiopulmonary stress testing using the treadmill Ramp protocol and the VEST. The anaerobic threshold (AT) was autodetermined using the V-slope method. The SVR was calculated by determining the mean blood pressure/cardiac output. Flow-mediated vasodilation (FMD) was measured in the brachial artery to evaluate endotheilial function. FMD and the percent change f'rom rest to AT in SVR correlated with those from rest to AT in ejection fraction and peak ejection ratio by VEST, respectively. Our findings suggest that FMD in the brachial artery and the SVR determined by VEST in patients with heart disease can possibly reflect cardiac function reserve during aerobic exercise.

Systemic peripheral vascular resistance as a determinant of functional cardiac reserve in response to exercise in patients with heart disease

Resting cardiac function is a poor indicator of functional cardiac reserve that is invoked during exercise. The objective of this study was to investigate the relationship between functional cardiac reserve and systemic vascular resistance (SVR) using an ambulatory radionuclide monitoring system (the Vest system) in patients with heart disease. The study population consisted of 29 patients (all male [mean +/- SD age, 63 +/- 10 years]), 23 with coronary artery disease, 3 with dilated cardiomyopathy, and 3 with hypertensive heart disease. All patients underwent cardiopulmonary stress testing using a ramped treadmill protocol and the Vest system. The anaerobic threshold (AT) was autodetermined using the V-slope method. Systemic vascular resistance was calculated using the mean blood pressure and cardiac output as determined using the Vest system parameters. All patients exercised beyond the AT until exhaustion. Resting left ventricular ejection fraction, peak ejection ratio, and peak filling ratio increased with the AT (P < .01 for all). Resting SVR decreased with the AT (P < .01). The percentage changes from rest to the AT in SVR correlated with those from rest to the AT in ejection fraction, peak ejection ratio, and peak filling ratio (r = -0.735, r = -0.510, and r = -0.697, respectively; P < .01). These findings indicate that SVR as recorded using the Vest system is a good determinant of functional cardiac reserve in patients with heart disease. Therefore, cardiopulmonary function testing combined with the Vest system is a good modality for the evaluation of functional cardiac reserve.

Variable response of conductance and resistance coronary arteries to endothelial stimulation in patients with heart failure due to nonischemic dilated cardiomyopathy

Attenuation of endothelial-dependent coronary vasodilation has been reported in idiopathic dilated cardiomyopathy and anatomically normal coronaries; however, data are insufficient for understanding the incidence and extent of this finding. The response of conductance and resistance coronary arteries to endothelial stimulation with acetylcholine was examined in 25 patients. Coronary blood flow had a variable response to acetylcholine and suggested coronary endothelial dysfunction in approximately half of the patients. Abnormal endothelial dysfunction involved the large conductance epicardial coronary arteries and the small resistance vessels. Abnormal endothelial response of coronary blood flow to acetylcholine could not be predicted by demographic and hemodynamic data.

CONCLUSIONS

Coronary artery endothelial function is heterogeneous in patients with idiopathic dilated cardiomyopathy. Endothelial dysfunction is present in approximately half of the cases and involves both resistance as well as conductance coronary blood vessels. Furthermore, coronary endothelial function cannot be predicted by demographic and hemo-dynamic parameters or left ventricular ejection fraction.

Electrical Stimulation of Skeletal Muscles An Alternative to Aerobic Exercise Training in Patients With Chronic Heart Failure?

The aim of this study was to investigate whether electrical stimulation of skeletal muscles could represent a rehabilitation alternative for patients with chronic heart failure (CHF). Thirty patients with CHF and NYHA class II-III were randomly assigned to a rehabilitation program using either electrical stimulation of skeletal muscles or bicycle training. Patients in the first group (n = 15) had 8 weeks of home-based low-frequency electrical stimulation (LFES) applied simultaneously to the quadriceps and calf muscles of both legs (1 h/day for 7 days/week); patients in the second group (n = 15) underwent 8 weeks of 40 minute aerobic exercise (3 times a week). After the 8-week period significant increases in several functional parameters were observed in both groups: maximal VO2 uptake (LFES group: from 17.5 +/- 4.4 mL/kg/min to 18.3 +/- 4.2 mL/kg/min, P < 0.05; bicycle group: from 18.1 +/- 3.9 mL/kg/min to 19.3 +/- 4.1 mL/kg/min, P < 0.01), maximal workload (LFES group: from 84.3 +/- 15.2 W to 95.9 +/- 9.8 W, P < 0.05; bicycle group: from 91.2 +/- 13.4 W to 112.9 +/- 10.8 W, P < 0.01), distance walked in 6 minutes (LFES group: from 398 +/- 105 m to 435 +/- 112 m, P < 0.05; bicycle group: from 425 +/- 118 m to 483 +/- 120 m, P < 0.03), and exercise duration (LFES group: from 488 +/- 45 seconds to 568 +/- 120 seconds, P < 0.05; bicycle group: from 510 +/- 90 seconds to 611 +/- 112 seconds, P < 0.03). These results demonstrate that an improvement of exercise capacities can be achieved either by classical exercise training or by home-based electrical stimulation. LFES should be considered as a valuable alternative to classical exercise training in patients with CHF.

Vascular endothelial dysfunction and mortality risk in patients with chronic heart failure

BACKGROUND

Endothelial function is known to be impaired in subjects with chronic heart failure (CHF), but the association between endothelial function and subsequent mortality risk in CHF has not been previously reported.

METHODS AND RESULTS

Biomarkers of endothelial function in the systemic arterial circulation (flow-mediated dilation [FMD] in the brachial artery) and the pulmonary circulation (exhaled nitric oxide [NO] production during submaximal exercise) were prospectively assessed in 259 subjects with New York Heart Association class II-III CHF. In subjects with FMD measurements (n=149), there were 12 deaths and 5 urgent transplantations over a median follow-up period of 841 days. In subjects with exhaled NO production measurements (n=110), there were 18 deaths and 1 urgent transplantation over a median follow-up period of 396 days. Both decreased FMD and decreased exhaled NO production were associated with increased risk of death or urgent transplantation after adjustment for other known CHF prognostic factors (age, etiology of CHF, functional class, left ventricular ejection fraction) in Cox multivariate proportional-hazards models (adjusted hazard ratio [HR] estimate for a 1% decrease in FMD=1.20; 95% confidence interval [CI], 1.03 to 1.45; P=0.027; adjusted HR estimate for a 1-ppb/min decrease in exhaled NO production=1.31, 95% CI, 1.01 to 1.69, P=0.04).

CONCLUSIONS

Endothelial dysfunction in CHF, as assessed by FMD in the brachial artery and exhaled NO production during submaximal exercise, is associated with an increased mortality risk in subjects with both ischemic and nonischemic CHF.

Evaluation of myocardial blood flow reserve in patients with chronic congestive heart failure due to idiopathic dilated cardiomyopathy

This study demonstrates a significant impairment in coronary blood flow reserve in most patients with idiopathic dilated cardiomyopathy despite normal epicardial coronary arteries. This change may prevent appropriate increases in coronary blood flow and thus lead to myocardial ischemia and progression of disease. An association between decreased response to adenosine and acetylcholine supports previous observations indicating that adenosine-induced vasodilation of coronary microcirculation is dependent on endothelial nitric oxide production.

Cardiac endothelial-myocardial signaling: its role in cardiac growth, contractile performance, and rhythmicity

Experimental work during the past 15 years has demonstrated that endothelial cells in the heart play an obligatory role in regulating and maintaining cardiac function, in particular, at the endocardium and in the myocardial capillaries where endothelial cells directly interact with adjacent cardiomyocytes. The emerging field of targeted gene manipulation has led to the contention that cardiac endothelial-cardiomyocytal interaction is a prerequisite for normal cardiac development and growth. Some of the molecular mechanisms and cellular signals governing this interaction, such as neuregulin, vascular endothelial growth factor, and angiopoietin, continue to maintain phenotype and survival of cardiomyocytes in the adult heart. Cardiac endothelial cells, like vascular endothelial cells, also express and release a variety of auto- and paracrine agents, such as nitric oxide, endothelin, prostaglandin I(2), and angiotensin II, which directly influence cardiac metabolism, growth, contractile performance, and rhythmicity of the adult heart. The synthesis, secretion, and, most importantly, the activities of these endothelium-derived substances in the heart are closely linked, interrelated, and interactive. It may therefore be simplistic to try and define their properties independently from one another. Moreover, in relation specifically to the endocardial endothelium, an active transendothelial physicochemical gradient for various ions, or blood-heart barrier, has been demonstrated. Linkage of this blood-heart barrier to the various other endothelium-mediated signaling pathways or to the putative vascular endothelium-derived hyperpolarizing factors remains to be determined. At the early stages of cardiac failure, all major cardiovascular risk factors may cause cardiac endothelial activation as an adaptive response often followed by cardiac endothelial dysfunction. Because of the interdependency of all endothelial signaling pathways, activation or disturbance of any will necessarily affect the others leading to a disturbance of their normal balance, leading to further progression of cardiac failure.

Vitamin C prevents hyperoxia-mediated vasoconstriction and impairment of endothelium-dependent vasodilation

High arterial blood oxygen tension increases vascular resistance, possibly related to an interaction between reactive oxygen species and endothelium-derived vasoactive factors. Vitamin C is a potent antioxidant capable of reversing endothelial dysfunction due to increased oxidant stress. We tested the hypotheses that hyperoxic vasoconstriction would be prevented by vitamin C, and that acetylcholine-mediated vasodilation would be blunted by hyperoxia and restored by vitamin C. Venous occlusion strain gauge plethysmography was used to measure forearm blood flow (FBF) in 11 healthy subjects and 15 congestive heart failure (CHF) patients, a population characterized by endothelial dysfunction and oxidative stress. The effect of hyperoxia on FBF and derived forearm vascular resistance (FVR) at rest and in response to intra-arterial acetylcholine was recorded. In both healthy subjects and CHF patients, hyperoxia-mediated increases in basal FVR were prevented by the coinfusion of vitamin C. In healthy subjects, hyperoxia impaired the acetylcholine-mediated increase in FBF, an effect also prevented by vitamin C. In contrast, hyperoxia had no effect on verapamil-mediated increases in FBF. In CHF patients, hyperoxia did not affect FBF responses to acetylcholine or verapamil. The addition of vitamin C during hyperoxia augmented FBF responses to acetylcholine. These results suggest that hyperoxic vasoconstriction is mediated by oxidative stress. Moreover, hyperoxia impairs acetylcholine-mediated vasodilation in the setting of intact endothelial function. These effects of hyperoxia are prevented by vitamin C, providing evidence that hyperoxia-derived free radicals impair the activity of endothelium-derived vasoactive factors.

Impaired endothelium-mediated vasodilation in heart failure: clinical evidence and the potential for therapy

Numerous studies in the last decade have clearly shown an attenuated endothelium-dependent vasodilation in patients with chronic heart failure. This abnormality has been demonstrated in the peripheral, pulmonary, and coronary circulation in patients with both ischemic and nonischemic cardiomyopathy; its magnitude correlates with the severity of symptoms. Endothelial dysfunction in patients with cardiomyopathy and a relatively new onset of symptoms suggests that change in endothelial function occurs early in the course of the disease. In contrast to other circulatory beds, renal circulation has shown significant vasodilatory response to endothelial stimulation. The development of endothelial dysfunction may not be homogeneous, and its magnitude may differ among circulatory systems. Although the clinical implications of the attenuated endothelium-dependent vasodilation in heart failure are not clear, this condition may lead to decreased organ perfusion, impaired exercise tolerance, and progression of disease. Many therapeutic interventions have resulted in improvement of endothelial function in patients with heart failure. Some of these interventions have also proven effective in enhancing exercise capacity, symptoms, and survival in patients with heart failure. This association suggests a therapeutic role for improvement of endothelial function in patients with chronic heart failure.

Blunted peripheral vasodilatory response is a hallmark of progressive deterioration in mild to moderate congestive heart failure

BACKGROUND

Several reports have shown that dilatory response to acetylcholine (ACh) and nitroprusside (SNP) is blunted in the limb vasculature in patients with congestive heart failure (CHF). However, it is not yet known whether this vascular dysfunction is related to clinical outcome. We have examined the relationship between peripheral vasodilatory response and prognosis of CHF.

METHODS AND RESULTS

A total of 46 patients with mild to moderate CHF were enrolled (mean age 56 years). Changes in forearm blood flow (FBF) during intra-arterial infusion of ACh and SNP were determined by plethysmography. FBF changes above baseline for each dose were cumulated and used as an index of endothelium-dependent (ACh) response and endothelium-independent (SNP) response, respectively. During the follow-up period (mean 32 months), 9 patients were admitted to the hospital for treatment of worsening refractory CHF, and 6 patients died suddenly or developed life-threatening arrhythmia. By Kaplan-Meier analysis, when all cardiac events were included, no significant differences were observed between any levels of vascular response in terms of prognosis. However, when deterioration events were analyzed separately, patients with SNP responses below the median (7.4 mL/min/dL) had significantly higher rates of hospital admission caused by worsening CHF than those with above the median responses (P <.05). This relationship was not found between ACh response and clinical outcome. By Cox multivariate analysis, blunted vasodilatory response to SNP was a significant predictor of worsening CHF (chi(2) = 3.95; P <.05).

CONCLUSION

This study has shown that patients with mild to moderate CHF showing a blunted vascular response to SNP rather than ACh were admitted to the hospital more frequently because of deterioration of CHF. This finding suggests that changes in vascular smooth muscle and/or vascular structure in the peripheral vasculature may be a critical element in the worsening of CHF.

Endothelial dysfunction in cirrhosis and portal hypertension

Portal hypertension (PHT) is a common clinical syndrome associated with chronic liver diseases; it is characterized by a pathological increase in portal pressure. Pharmacotherapy for PHT is aimed at reducing both intrahepatic vascular tone and elevated splanchnic blood flow. Due to the altered hemodynamic profile in PHT, dramatic changes in mechanical forces, both pressure and flow, may play a pivotal role in controlling endothelial and vascular smooth muscle cell signaling, structure, and function in cirrhotics. Nitric oxide, prostacyclin, endothelial-derived contracting factors, and endothelial-derived hyperpolarizing factor are powerful vasoactive substances released from the endothelium in response to both humoral and mechanical stimuli that can profoundly affect both the function and structure of the underlying vascular smooth muscle. This review will examine the contributory role of hormonal- and mechanical force-induced changes in endothelial function and signaling and the consequence of these changes on the structural and functional response of the underlying vascular smooth muscle. It will focus on the pivotal role of hormonal and mechanical force-induced endothelial release of vasoactive substances in dictating the reactivity of the underlying vascular smooth muscle, i.e., whether hyporeactive or hyperreactive, and will examine the extent to which these substances may exert a protective and/or detrimental influence on the structure of the underlying vascular smooth muscle in both a normal hemodynamic environment and following hemodynamic perturbations typical of PHT and cirrhosis. Finally, it will discuss the intracellular processes that regulate the release/expression of these vasoactive substances and that control the transformation of this normally protective cell to one that may promote the development of vasculopathy in PHT.

Endothelial NO/cGMP system contributes to natriuretic peptide-mediated coronary and peripheral vasodilation

We tested the hypothesis that the endothelial nitric oxide (NO)-soluble guanylyl cyclase system is involved in atrial natriuretic peptide (ANP) and C-type natriuretic peptide (CNP) mediated regulation of coronary and peripheral vascular resistance. Rat hearts were perfused via the aorta at constant flow and the effect of ANP and CNP on coronary perfusion pressure and release of cGMP was determined in the absence and presence of the nitric oxide synthase inhibitor NG-nitro-L-arginine (L-NNA; 0.2 mmol/L) and the specific inhibitor of soluble guanylyl cyclase ODQ (20 micromol/L), respectively (n = 6). ANP (10-300 nmol/L) reduced perfusion pressure from 133 +/- 2 to 53 +/- 2 mm Hg (-60%; control) in the presence of L-NNA from 132 +/- 1 to 71 +/- 1 mm Hg (-46%) and in the presence of ODQ from 133 +/- 1 to 85 +/- 2 (-36%) (n = 6; P < 0.05). Disruption of the coronary endothelium by perfusion of hearts with collagenase reduced the relaxant effect of ANP to a similar extent as L-NNA. Basal release of cGMP was increased up to sixfold by ANP and this increase was reduced by L-NNA and ODQ (n = 6; P < 0.05). The coronary relaxant effect of CNP (0.1-3 micromol/L) was similarly attenuated by L-NNA and ODQ (n = 6). In conscious mice, a low dose of L-NNA (30 nmol) consistently reduced the blood pressure lowering effect of ANP (30 nmol) by approximately 40% (n = 7), whereas the hypotensive effect of nitroprusside (0.15 micromol) was not affected (n = 5). We conclude that the coronary dilatory and hypotensive action of natriuretic peptides involves the endothelium and is partly mediated by soluble guanylyl cyclase. The data may explain previous observations in humans with congestive heart failure showing impaired vascular ANP responses.