Increased blood pressure variability in pheochromocytoma compared to essential hypertension patients

Update on clinical characteristics in the evaluation of phaeochromocytoma and paraganglioma

Pheochromocytomas and sympathetic paragangliomas (PPGL) are rare neuroendocrine tumors originating from chromaffin tissue of the adrenal medulla and extra-adrenal sympathetic paraganglia. Historically, many of these tumors were diagnosed postmortem, earning pheochromocytomas the moniker "great mimic" due to their diverse clinical manifestations that can resemble various other conditions. Over time, the clinical presentation of PPGL has evolved, with a shift from symptomatic or postmortem diagnoses to more frequent incidental discoveries or diagnoses through screening, with postmortem identification now being rare. The development of a clinical scoring system has improved the identification of patients at increased risk for PPGL. Notably, the proportion of PPGL patients with normal blood pressure ranges from 15 % to 40 %, varying based on the clinical context. Despite the tumor's reputation, PPGL is an exceedingly rare cause of resistant hypertension. Management of a pheochromocytoma crisis has advanced, with several classes of drugs available for treatment. However, PPGL during pregnancy remains a significant concern, associated with substantial maternal and fetal mortality rates. Additionally, PPGL can present as rare disorders, including catecholamine-induced cardiomyopathy, Cushing syndrome, and urinary bladder PGL. Given these varied presentations, heightened awareness and prompt recognition of PPGL are crucial for timely diagnosis and treatment, ultimately improving patient outcomes. In this article, we offer an in-depth analysis of the diverse clinical presentations of PPGL, highlighting their complexity and the associated diagnostic and treatment strategies.

Ambulatory blood pressure monitoring in pheochromocytoma - paraganglioma: A single center experience

CONTEXT/AIMS

Pheochromocytoma and paraganglioma (PPGL) are rare tumors, and data on ambulatory blood pressure monitoring (ABPM) in these patients and the effect of blocking on ABPM parameters is limited. We aimed to describe ABPM parameters in a cohort of PPGL at our center in western India.

METHODS

Retrospective study of patients with PPGL whose ABPM data was available. Demographic details, secretory status, and ABPM data were retrieved. Coefficient of variability (CV) was calculated as standard deviation/mean in percentage.

RESULTS

In the 39 included patients, mean age at presentation was 39.3 ± 14.2 yr; 20 (51.3%) were males, 25 (64.1%) hypertensive, and mean tumor diameter was 5.3 cm. In 18 patients whose baseline ABPM was done without medications, those with nocturnal blood pressure dipping (6/18, 33%) had higher serum metanephrines (median 313.2 vs. 34.7 pg/ml, P = 0.028). Despite normal office blood pressure (BP), 8.9% of systolic BP readings were >140 mmHg, and 1.2% were >160 mmHg. Among 29 patients with both pre and post-block ABPM, mean BP (systolic 121.6 vs. 132.5 mmHg, P = 0.014; diastolic 68.9 vs. 76.4 mmHg, P = 0.005) and percentage of BP readings above 140 mmHg (median 9.4% vs. 24.4%, P = 0.016) were significantly lowered after the preoperative blockade in hypertensive ( n = 19) patients, whereas CV was similar. The post-blockade ABPM characteristics were similar in patients blocked with amlodipine or prazosin.

CONCLUSION

ABPM provides additional information about BP characteristics in PPGL. The preoperative blocking decreases the magnitude of BP excursions but does not affect BP variability.

Effects of vasodilators on beat-to-beat and every fifteen minutes blood pressure variability induced by noradrenaline infusion in rats

Increased blood pressure variability (BPV) was shown to be associated with cardiovascular morbidities and/or mortalities. There are various types of BPV depending on time intervals of BP measurements, ranging from beat-to-beat to visit-to-visit or year-to-year. We previously found that continuous infusion of noradrenaline (NA) for 14 days increased short-term BPV every 15 min in rats. The aims of this study were to examine (1) whether NA infusion increases very short-term beat-to-beat BPV, (2) the effects of azelnidipine and hydralazine on NA-induced BPV, and (3) whether baroreceptor reflex sensitivity (BRS) is affected by NA or NA plus those vasodilators. Nine-week-old Wistar rats infused subcutaneously with 30 μg/h NA were orally treated with or without 9.7 mg/day azelnidipine or 5.9 mg/day hydralazine over 14 days. BP levels were continuously monitored via abdominal aortic catheter with a telemetry system in an unrestrained condition. Standard deviations (SDs) were used to evaluate beat-to-beat BPV and BPV every 15 min which was obtained by averaging BP levels for 10-s segment at each time point. BRS was determined by a sequence analysis. Continuous NA infusion over 14 days increased average BP, beat-to-beat BPV, and BPV every 15 min, lowering BRS. Comparing the two vasodilators, hydralazine reduced BP elevation by NA; meanwhile, azelnidipine alleviated BPV augmentation, preserving BRS, despite a smaller BP reduction. Thus, NA infusion increased both very short- and short-term BPV concomitantly with impaired BRS, while azelnidipine had an inhibitory effect, possibly independent of BP-lowering, on those types of BPV and impairment of BRS.

Perioperative Management of Pheochromocytomas and Sympathetic Paragangliomas

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors arising from chromaffin cells of the adrenal medulla or extra-adrenal paraganglia, respectively. PPGLs have the highest degree of heritability among endocrine tumors. Currently, ~40% of individuals with PPGLs have a genetic germline and there are at least 12 different genetic syndromes related to these tumors. Metastatic PPGLs are defined by the presence of distant metastases at sites where chromaffin cells are physiologically absent. Approximately 10% of pheochromocytomas and ~40% of sympathetic paragangliomas are linked to metastases, explaining why complete surgical resection is the first-choice treatment for all PPGL patients. The surgical approach is a high-risk procedure requiring perioperative management by a specialized multidisciplinary team in centers with broad expertise. In this review, we summarize and discuss the most relevant aspects of perioperative management in patients with pheochromocytomas and sympathetic paragangliomas.

Effect of adrenalectomy on remission of subclinical left ventricular dysfunction in patients with pheochromocytoma: a speckle-tracking echocardiography study

BACKGROUND

Pheochromocytomas (PHEO) are tumours with the ability to produce, metabolize and secrete catecholamines. Catecholamines overproduction leads to the decrease of longitudinal function of the left ventricle (LV) measured by speckle-tracking echocardiography. Patients with PHEO have a lower magnitude of global longitudinal strain (GLS) than patients with essential hypertension. GLS normalization is expected after resolution of catecholamine overproduction.

METHODS

Twenty-four patients (14 females and 10 males) with a recent diagnosis of PHEO have been examined before and 1 year after adrenalectomy. An echocardiographic examination including speckle-tracking analysis with the evaluation of GLS and regional longitudinal strain (LS) in defined groups of LV segments (basal, mid-ventricular and apical) was performed.

RESULTS

One year after adrenalectomy, the magnitude of GLS increased (-14.3 ± 1.8 to -17.7 ± 1.6%; P < 0.001). When evaluating the regional LS, the most significant increase in the differences was evident in the apical segment compared to mid-ventricular and basal segments of LV (-5.4 ± 5.0 vs -1.9 ± 2.7 vs -1.6 ± 3.8; P < 0.01).

CONCLUSIONS

In patients with PHEO, adrenalectomy leads to an improvement of subclinical LV dysfunction represented by the increasing magnitude of GLS, which is the most noticeable in apical segments of LV.

Blood Pressure Profile, Catecholamine Phenotype, and Target Organ Damage in Pheochromocytoma/Paraganglioma

CONTEXT

Impaired diurnal blood pressure (BP) variability is related to higher cardiovascular risk.

OBJECTIVE

To assess diurnal variability of BP and its relation to target organ damage (TOD) and catecholamine phenotype in a consecutive sample of pheochromocytoma/paraganglioma (PPGL).

DESIGN

We included 179 patients with PPGL All patients underwent 24 hours of ambulatory BP monitoring to determine dipping status. Differences in plasma metanephrine or urine adrenaline were used to distinguish catecholamine biochemical phenotype. To evaluate TOD, renal functions, presence of left ventricle hypertrophy (LVH), and the subgroup (n = 111) carotid-femoral pulse wave velocity (PWV) were assessed. Structural equation modeling was used to find the relationship among nocturnal dipping, catecholamine phenotype, and TOD parameters.

RESULTS

According to the nocturnal dipping, patients were divided into the three groups: dippers (28%), nondippers (40%), and reverse dippers (32%). Reverse dippers were older (P < 0.05), with a higher proportion of noradrenergic (NA) phenotype (P < 0.05), a higher prevalence of diabetes mellitus (P < 0.05), and sustained arterial hypertension (P < 0.01) and its duration (P < 0.05), as opposed to the other groups. All parameters of TOD were more pronounced only in reverse dippers compared with nondippers and dippers. The presence of NA phenotype (=absence of adrenaline production) was associated with reverse dipping and TOD (LVH and PWV).

CONCLUSIONS

Patients with reverse dipping had more substantial TOD compared with other groups. The NA phenotype plays an important role, not only in impaired diurnal BP variability but also independently from dipping status in more pronounced TOD of heart and vessels.

Augmented blood pressure variability following continuous infusion of noradrenaline in rats

OBJECTIVE

Augmented blood pressure (BP) variability has been shown to be associated with cardiovascular diseases. Activity of the sympathetic nervous system is an important determinant factor of the 24-h profile of BP variability, although it is unknown whether persistent adrenergic activation causes augmented BP variability or not. Here we report that continuous infusion of noradrenalin augments 24-h BP variability in rats.

METHODS

Nine-week-old male Wistar rats were continuously infused with subcutaneous 30 μg/h noradrenalin, 150 μg/h of the α1-adrenergic agonist phenylephrine, or 30 μg/h of the β-agonist isoproterenol, for 14 days. Noradrenalin-infused rats were also administered either oral 5 mg/day prazosin or 50 mg/day atenolol during the infusion period. BP variability was evaluated before and after 7 and 14 days of the infusion, using a coefficient of variation of BP recorded every 15 min under an unrestrained condition via an abdominal aortic catheter by a radiotelemetry system.

RESULTS

Continuous infusion of noradrenalin significantly increased 24-h BP variability at 7 and 14 days, slightly elevating BP levels, while this increase in BP variability was partially attenuated by prazosin, but not by atenolol. Continuous infusion of phenylephrine augmented BP variability, but isoproterenol had no effect on the variability.

CONCLUSION

Continuous infusion of noradrenalin augmented 24-h BP variability partly through an α1-adrenergic receptor-mediated mechanism in rats, suggesting that the noradrenalin-infused rat is an animal model of augmented BP variability induced by persistent adrenergic activation.

Analysis of Short-term Blood Pressure Variability in Pheochromocytoma/Paraganglioma Patients

Data on short-term blood pressure variability (BPV), which is a well-established cardiovascular prognostic tool, in pheochromocytoma and paraganglioma (PPGL) patients is still lack and conflicting. We retrospectively evaluated 23 PPGL patients referred to our unit from 2010 to 2019 to analyze 24 h ambulatory blood pressure monitoring (24-h ABPM)-derived markers of short-term BPV, before and after surgical treatment. PPGL diagnosis was assessed according to guidelines and confirmed by histologic examination. The 24-h ABPM-derived markers of short-term BPV included: circadian pressure rhythm; standard deviation (SD) and weighted SD (wSD) of 24-h, daytime, and night-time systolic and diastolic blood pressure (BP); average real variability (ARV) of 24-h, daytime, and night-time systolic and diastolic BP. 7 males and 16 females of 53 ± 18 years old were evaluated. After surgical resection of PPGL we found a significant decrease in 24-h systolic BP ARV (8.8 ± 1.6 vs. 7.6 ± 1.3 mmHg, p < 0.001), in 24-h diastolic BP ARV (7.5 ± 1.6 vs. 6.9 ± 1.4 mmHg, p = 0.031), and in wSD of 24-h diastolic BP (9.7 ± 2.0 vs 8.8 ± 2.1 mmHg, p = 0.050) comparing to baseline measurements. Moreover, baseline 24-h urinary metanephrines significantly correlated with wSD of both 24-h systolic and diastolic BP. Our study highlights as PPGL patients, after proper treatment, show a significant decrease in some short-term BPV markers, which might represent a further cardiovascular risk factor.

Hypertension and hypertensive cardiomyopathy in patients with a relapse-free history of phaeochromocytoma

BACKGROUND

In patients with a relapse-free history of phaeochromocytoma/paraganglioma (PCC/PGL), persistent hypertension has been reported, but has not been well characterized.

METHODS

In 28 patients [mean age 54·5 (26-81) years] with a relapse-free history of PCC/PGLs, we prospectively analysed resting, supine blood pressure (BP), ambulatory BP, echocardiography, exercise testing, metabolic parameters and retrospectively collected data from the time of diagnosis (baseline). Echocardiographic measures were compared to healthy (n = 28) and hypertensive controls (n = 15).

RESULTS

Median follow-up was 6 [1-16] years. Three patients had normal office and ambulatory BP and three patients had only increased office BP. Fifty-four per cent of patients had a blunted circadian rhythm. Comparing normal, hypertensive and PCC/PGL patients, we found significant differences in end-diastolic septal thickness (8·8 ± 0·2, 13·8 ± 0·4, 10·0 ± 0·3 mm, P < 0·05), septal basal thickness (9·0 ± 0·3, 15·9 ± 0·5, 11·2 ± 0·4 mm, P < 0·05) and left ventricular mass (143 ± 8, 255 ± 19, 169 ± 9 g, P < 0·05). In five patients, seven major cardiovascular events were observed. Compared to baseline, no significant difference was found in systolic (140 ± 35 vs 137 ± 18 mmHg) and diastolic (85 ± 18 vs 83 ± 10 mmHg) BP. An increase or a decrease in BP (>10 mmHg) was found in 36% and 39% of patients, respectively. The number of antihypertensive drugs had not changed [1 (0-3) vs 1 (0-4)]. Fewer patients received insulin (1 vs 3) or oral antiglycaemic drugs (2 vs 7).

CONCLUSION

Our data indicate that hypertension persists after removal of PCG/PGL in a substantial proportion of patients. Hypertensive heart disease is common, and cardiovascular events are frequent in patients with a history of PCC/PGL.

Pathophysiology and diagnosis of disorders of the adrenal medulla: focus on pheochromocytoma

The principal function of the adrenal medulla is the production and secretion of catecholamines. During stressful challenging conditions, catecholamines exert a pivotal homeostatic role. Although the main adrenomedullary catecholamine, epinephrine, has a wide array of adrenoreceptor-mediated effects, its absence does not cause life-threatening problems. In contrast, excess production of catecholamines due to an adrenomedullary tumor, specifically pheochromocytoma, results in significant morbidity and mortality. Despite being rare, pheochromocytoma has a notoriously bad reputation because of its potential devastating effects if undetected and untreated. The paroxysmal signs and symptoms and the risks of missing or delaying the diagnosis are well known for most physicians. Nevertheless, even today the diagnosis is still overlooked in a considerable number of patients. Prevention and complete cure are however possible by early diagnosis and appropriate treatment but these patients remain a challenge for physicians. Yet, biochemical proof of presence or absence of catecholamine excess has become more easy and straightforward due to developments in assay methodology. This also applies to radiological and functional imaging techniques for locating the tumor. The importance of genetic testing for underlying germline mutations in susceptibility genes for patients and relatives is increasingly recognized. Yet, the effectiveness of genetic testing, in terms of costs and benefits to health, has not been definitively established. Further improvement in knowledge of genotype-phenotype relationships in pheochromocytoma will open new avenues to a more rationalized and personalized diagnostic approach of affected patients.

Pheochromocytoma

Pheochromocytoma and paraganglioma are catecholamine-producing tumors that are associated with substantial serious morbidity and mortality. A carefully taken medical history and early consideration of such tumors are key for early diagnosis and treatment. The biochemical diagnosis should include measurements of metanephrines in either plasma or urine. In addition to anatomical imaging, sensitive functional imaging modalities offer extra benefit for most patients in locating the tumor and eventual metastases. In at least 30% of all patients with a pheochromocytoma/paraganglioma, an underlying germline is responsible for tumor development and genetic testing should be considered in all patients. Current treatment options for malignant pheochromocytoma/paraganglioma are still very modest. New developments in the therapeutic armamentarium may improve the prospect for these patients.

Anti-hypertensive treatment in pheochromocytoma and paraganglioma: current management and therapeutic features

Pheochromocytoma (PH) and paraganglioma (PG) are neuroendocrine neoplasms arising from chromaffin cells of the adrenal medulla and the sympathetic ganglia, respectively. Although are unusual cause of hypertension (HT) accounting for at most 0.1-0.2 % of cases, they may lead to severe and potentially lethal hypertensive crisis due to the effects of the released catecholamines. However, both PH and PG may be asymptomatic as ~30 % of subjects are normotensive or have orthostatic hypotension and in these cases the 24 h ambulatory blood pressure (BP) monitoring is an important toll to diagnose and treat HT. HT treatment may be difficult when PH or PG occurs in pregnancy or in the elderly subjects and in these cases a multidisciplinary team is required. When surgical excision is mandatory the perioperative management requires the administration of selective α1-adrenergic blocking agents (i.e., doxazosin, prazosin or terazosin) followed by a β-adrenergic blockade (i.e., propranolol, atenolol). This latter should never be started first because blockade of vasodilatory peripheral β-adrenergic receptors with unopposed α-adrenergic receptor stimulation can lead to a further elevation of BP. Although labetalol is traditionally considered the ideal agent due to its α- and β-adrenergic antagonism, experimental studies do not support its use in this clinical setting. As second regimen, the administration of vasodilators as calcium channel blockers (i.e., nicardipine, nifedipine) may be required to control BP. Oral and sublingual short-acting nifedipine are potentially dangerous in patients with hypertensive emergencies and are not recommend. The latest evidences into the diagnosis and treatment of hypertensive crisis due to PH and PG are reviewed here.

Is the excess cardiovascular morbidity in pheochromocytoma related to blood pressure or to catecholamines?

BACKGROUND

It is generally accepted that pheochromocytoma is associated with an increased cardiovascular risk. This is however not based on studies with an appropriate control group of patients with essential hypertension.

AIM OF THE STUDY

We examined whether patients with pheochromocytoma have an excess cardiovascular morbidity as compared to hypertensive patients.

METHODS

In a retrospective case-control study we reviewed the medical charts of 109 pheochromocytoma patients for cardiovascular events within 5 years prior to the diagnosis. These patients were matched to control patients with essential hypertension for gender and year of birth and diagnosis. Outcome variables were ischemic heart disease, cerebrovascular accidents, and transient ischemic attacks. Classical cardiovascular risk factors were also assessed.

RESULTS

A significantly higher rate of patients with pheochromocytoma suffered a cardiovascular event (13.8%; 95% confidence interval: 7.9%-21.6%) as compared to hypertensive patients (1.1%, 95% confidence interval: 0.1%-3.9%) (P < .001). Blood pressure level was lower in pheochromocytoma patients (153/91 ± 35/15 mm Hg) than in hypertensive patients (170/103 ± 18/8 mm Hg) (P < .001), even after correction for use of antihypertensive medication (P < .02). The difference in event rates could not be attributed to differences in other cardiovascular risk factors.

CONCLUSIONS

Pheochromocytoma patients have a clearly higher rate of cardiovascular events than patients with essential hypertension. This cannot be attributed to differences in blood pressure or other cardiovascular risk factors. The most likely explanation for the excess event rate is the prolonged exposure to the toxic effects of tumoral catecholamines. These data underpin the importance of a timely diagnosis and treatment of pheochromocytoma.

Cardiovascular magnetic resonance in systemic hypertension

Systemic hypertension is a highly prevalent potentially modifiable cardiovascular risk factor. Imaging plays an important role in the diagnosis of underlying causes for hypertension, in assessing cardiovascular complications of hypertension, and in understanding the pathophysiology of the disease process. Cardiovascular magnetic resonance (CMR) provides accurate and reproducible measures of ventricular volumes, mass, function and haemodynamics as well as uniquely allowing tissue characterization of diffuse and focal fibrosis. In addition, CMR is well suited for exclusion of common secondary causes for hypertension. We review the current and emerging clinical and research applications of CMR in hypertension.

Cardiovascular manifestations of phaeochromocytoma

Clinical expression of phaeochromocytoma may involve numerous cardiovascular manifestations, but usually presents as sustained or paroxysmal hypertension associated with other signs and symptoms of catecholamine excess. Most of the life-threatening cardiovascular manifestations of phaeochromocytoma, such as hypertensive emergencies, result from a rapid and massive release of catecholamines from the tumour. More rarely, patients with phaeochromocytoma present with low blood pressure or even shock that may then precede multisystem crisis. Sinus tachycardia, with palpitations as the presenting symptom, is the most prevalent abnormality of cardiac rhythm in phaeochromocytoma, but tumours can also be associated with more serious ventricular arrhythmias or conduction disturbances. Reversible dilated or hypertrophic cardiomyopathy are well established cardiac manifestations of phaeochromocytoma, with more recent attention to an increasing number of cases with Takotsubo cardiomyopathy. This review provides an update on the cause, clinical presentation and treatment of the cardiovascular manifestations of phaeochromocytoma. As the cardiovascular complications of phaeochromocytoma can be life-threatening, all patients who present with manifestations that even remotely suggest excessive catecholamine secretion should be screened for the disease.

Hypertension in pheochromocytoma: characteristics and treatment

Pheochromocytoma is a tumor of the chromaffin cells in the adrenal medulla and sympathetic paraganglia, which synthesizes and secretes catecholamines. Norepinephrine, epinephrine, and dopamine all act on their target receptors, which causes a physiologic change in the body. High circulating levels of catecholamines can lead to severe hypertension and can have devastating effects on multiple body systems (eg, cardiovascular, cerebrovascular), and can lead to death if untreated. Although surgical treatment represents the only modality of ultimate cure, pharmacologic preoperative treatment remains the mainstay of successful outcome.

Update: Systemic Diseases and the Cardiovascular System (II). The endocrine system and the heart: a review

Normal endocrine function is essential for cardiovascular health. Disorders of the endocrine system, consisting of hormone hyperfunction and hypofunction, have multiple effects on the cardiovascular system. In this review, we discuss the epidemiology, diagnosis, and management of disorders of the pituitary, thyroid, parathyroid, and adrenal glands, with respect to the impact of endocrine dysfunction on the cardiovascular system. We also review the cardiovascular benefits of restoring normal endocrine function.

Update: Systemic Diseases and the Cardiovascular System (II). The endocrine system and the heart: a review

Normal endocrine function is essential for cardiovascular health. Disorders of the endocrine system, consisting of hormone hyperfunction and hypofunction, have multiple effects on the cardiovascular system. In this review, we discuss the epidemiology, diagnosis, and management of disorders of the pituitary, thyroid, parathyroid, and adrenal glands, with respect to the impact of endocrine dysfunction on the cardiovascular system. We also review the cardiovascular benefits of restoring normal endocrine function.

Factors influencing arterial stiffness in pheochromocytoma and effect of adrenalectomy

The aim of the study was to evaluate arterial stiffness and its modulating factors measured by carotid-femoral pulse wave velocity (PWV) and central augmentation index (AI) in patients with pheochromocytoma (PHEO) before and after surgery. Forty-five patients with PHEO and 45 healthy controls were investigated using an applanation tonometer (SphygmoCor, AtCor Medical). The gender, age, BMI and lipid profiles were comparable among both groups. The main difference in basic characteristic was as expected for fasting plasma glucose (P<0.001) and all blood pressure modalities. PWV in PHEO was significantly higher than in controls (7.2+/-1.4 vs. 5.8+/-0.5 ms(-1); P<0.001). Between-group difference in PWV remained significant even after the adjustment for age, heart rate, fasting plasma glucose and each of brachial (P<0.001) and 24 h blood pressure parameters (P<0.01). The difference in AI between groups did not reach the statistical significance (19+/-14 vs. 16+/-13%; NS). In multiple regression analysis, age (P<0.001), mean blood pressure (P=0.002), high-sensitive C-reactive protein (hs-CRP) (P=0.007) and 24 h urine norepinephrine (P=0.007) were independently associated with PWV in PHEO. In addition, 27 patients with PHEO were studied 1 year after tumor removal. Successful tumor removal led to a significant decrease in PWV (7.0+/-1.2 vs. 6.0+/-1.1 ms(-1); P<0.001). In conclusion, patients with PHEO have an increase in PWV, which is reversed by the successful tumor removal. Age, mean blood pressure, hs-CRP and norepinephrine levels are independent predictors of PWV.

Cardiovascular complications in patients with pheochromocytoma: a mini-review

Phaeochromocytomas are rare neuroendocrine tumours secreting high levels of catecholamines, able to exert serious metabolic and cardiovascular effects. The serious and potentially lethal cardiovascular complications of these tumours are due to the potent effects of secreted catecholamines, especially noradrenaline, the main transmitter released from sympathetic nerve terminals. Hypertension, tachycardia, pallor, headache and anxiety, usually dominate the clinical presentation. Occasionally, patients with predominantly epinephrine-secreting tumours present hypotension or even shock. Other cardiovascular complications of pheochromocytoma include ischaemic heart disease, acute myocardial infarction, cardiac arrhythmias, heart failure due to toxic cardiomyopathy, or pulmonary edema. Catecholamines have been shown to influence the extracellular matrix with collagen deposition and subsequent fibrosis in the arterial wall and in the myocardium. These morphofunctional changes of the myocardium and of arterial wall can be emphasized by ultrasound imaging. Indeed, ultrasound imaging of the myocardium and arterial wall not only identifies wall thickness but also contains information on texture that may be revealed by acoustic tissue characterization. The latter can be quantified through videodensitometric analysis of echographic images or through ultrasonic integrated backscatter signal analysis. This paper reviews cardiovascular complications in patients with pheochromocytoma and utility of the new ultrasound technique as backscatter signal. It is useful for evaluating preclinical pathological morphofunctional changes of the myocardium and arterial wall, characterized by increased collagen content in pheochromocytoma patients. The recognition of early catecholamine-induced alterations in patients with pheochromocytoma, is important to prevent at least morbidity and mortality, before surgical treatment.

Update on pediatric pheochromocytoma

Pheochromocytomas are rare tumors in children arising from chromaffin cells of adrenal medullary or extra-adrenal paraganglionic tissue. The tumors are characterized by synthesis, metabolism, and secretion of catecholamines. The formerly used guidelines for pheochromocytoma have been changed by recent discoveries, implementation of new approaches, and understanding of biochemistry, genetics, imaging, pathophysiology, and nomenclature of these tumors. In children, pheochromocytomas are more frequently familial, extra-adrenal, bilateral, and multifocal than in adults. Because of a highly variable clinical presentation, pheochromocytoma is often referred to as the great mimic. Measurements of plasma or urinary fractionated metanephrines are recommended as first-line biochemical tests for diagnosis, with optimum diagnostic sensitivity to be preferred over specificity. In general, localization studies must be used secondary to clinical and biochemical evidence. Adequate preoperative treatment with alpha-blockade is mandatory, including for pheochromocytomas that do not secrete but only synthesize catecholamines. Because approximately 40% of pheochromocytomas in children have a hereditary basis, proper genetic testing should be performed, with appropriate implications for future follow-up and treatment options. The risk for development of malignant disease depends highly on the underlying mutation, which may also impact recommendations concerning screening and surgical or systemic treatment. This article reviews recent advances in biochemistry, genetics, and imaging and outlines recommendations for improved evaluation and treatment of children with benign or malignant pheochromocytomas.

Causes and mechanisms of nondipping hypertension

Growing evidence indicates that nondippers have worsened cardiovascular outcomes than dippers. Ambulatory blood pressure monitoring with a lack of nocturnal BP fall (nondipping) have also been shown to be more closely associated with target organ damage and worsened cardiovascular outcome than in patients with essential hypertension with dipping pattern. The underlying pathogenetic mechanisms potentially linking nondipping with cardiovascular disease are not fully understood. There are multiple possible underlying pathophysiologic mechanisms in the impaired BP decline during the night. Extrinsic and intrinsic factors including abnormal neurohormonal regulation, lack of physical activity, nutritional factors such as increased dietary sodium intake, and smoking of tobacco have been implicated for blunted circadian rhythm of BP. Certain diseases such as diabetes and chronic renal diseases also affect the circadian BP rhythm. Currently, the clinical importance of nondipping is known well; however, the relationship between certain disease states and nondipping has not been fully explained yet. This paper will attempt to address to clarify the underlying basis for nondipping and the specific associations with various disease states.

Resistant hypertension: diagnosis, evaluation, and treatment: a scientific statement from the American Heart Association Professional Education Committee of the Council for High Blood Pressure Research

Resistant hypertension is a common clinical problem faced by both primary care clinicians and specialists. While the exact prevalence of resistant hypertension is unknown, clinical trials suggest that it is not rare, involving perhaps 20% to 30% of study participants. As older age and obesity are 2 of the strongest risk factors for uncontrolled hypertension, the incidence of resistant hypertension will likely increase as the population becomes more elderly and heavier. The prognosis of resistant hypertension is unknown, but cardiovascular risk is undoubtedly increased as patients often have a history of long-standing, severe hypertension complicated by multiple other cardiovascular risk factors such as obesity, sleep apnea, diabetes, and chronic kidney disease. The diagnosis of resistant hypertension requires use of good blood pressure technique to confirm persistently elevated blood pressure levels. Pseudoresistance, including lack of blood pressure control secondary to poor medication adherence or white coat hypertension, must be excluded. Resistant hypertension is almost always multifactorial in etiology. Successful treatment requires identification and reversal of lifestyle factors contributing to treatment resistance; diagnosis and appropriate treatment of secondary causes of hypertension; and use of effective multidrug regimens. As a subgroup, patients with resistant hypertension have not been widely studied. Observational assessments have allowed for identification of demographic and lifestyle characteristics associated with resistant hypertension, and the role of secondary causes of hypertension in promoting treatment resistance is well documented; however, identification of broader mechanisms of treatment resistance is lacking. In particular, attempts to elucidate potential genetic causes of resistant hypertension have been limited. Recommendations for the pharmacological treatment of resistant hypertension remain largely empiric due to the lack of systematic assessments of 3 or 4 drug combinations. Studies of resistant hypertension are limited by the high cardiovascular risk of patients within this subgroup, which generally precludes safe withdrawal of medications; the presence of multiple disease processes (eg, sleep apnea, diabetes, chronic kidney disease, atherosclerotic disease) and their associated medical therapies, which confound interpretation of study results; and the difficulty in enrolling large numbers of study participants. Expanding our understanding of the causes of resistant hypertension and thereby potentially allowing for more effective prevention and/or treatment will be essential to improve the long-term clinical management of this disorder.

Resistant hypertension: diagnosis, evaluation, and treatment. A scientific statement from the American Heart Association Professional Education Committee of the Council for High Blood Pressure Research

Resistant hypertension is a common clinical problem faced by both primary care clinicians and specialists. While the exact prevalence of resistant hypertension is unknown, clinical trials suggest that it is not rare, involving perhaps 20% to 30% of study participants. As older age and obesity are 2 of the strongest risk factors for uncontrolled hypertension, the incidence of resistant hypertension will likely increase as the population becomes more elderly and heavier. The prognosis of resistant hypertension is unknown, but cardiovascular risk is undoubtedly increased as patients often have a history of long-standing, severe hypertension complicated by multiple other cardiovascular risk factors such as obesity, sleep apnea, diabetes, and chronic kidney disease. The diagnosis of resistant hypertension requires use of good blood pressure technique to confirm persistently elevated blood pressure levels. Pseudoresistance, including lack of blood pressure control secondary to poor medication adherence or white coat hypertension, must be excluded. Resistant hypertension is almost always multifactorial in etiology. Successful treatment requires identification and reversal of lifestyle factors contributing to treatment resistance; diagnosis and appropriate treatment of secondary causes of hypertension; and use of effective multidrug regimens. As a subgroup, patients with resistant hypertension have not been widely studied. Observational assessments have allowed for identification of demographic and lifestyle characteristics associated with resistant hypertension, and the role of secondary causes of hypertension in promoting treatment resistance is well documented; however, identification of broader mechanisms of treatment resistance is lacking. In particular, attempts to elucidate potential genetic causes of resistant hypertension have been limited. Recommendations for the pharmacological treatment of resistant hypertension remain largely empiric due to the lack of systematic assessments of 3 or 4 drug combinations. Studies of resistant hypertension are limited by the high cardiovascular risk of patients within this subgroup, which generally precludes safe withdrawal of medications; the presence of multiple disease processes (eg, sleep apnea, diabetes, chronic kidney disease, atherosclerotic disease) and their associated medical therapies, which confound interpretation of study results; and the difficulty in enrolling large numbers of study participants. Expanding our understanding of the causes of resistant hypertension and thereby potentially allowing for more effective prevention and/or treatment will be essential to improve the long-term clinical management of this disorder.

Perioperative hypertension in phaeochromocytoma patients undergoing adrenalectomy

This study was designed to compare perioperative blood pressure (BP) management in hypertensive patients with phaeochromocytoma undergoing preoperative α-blockade and in patients with other suprarenal gland tumors. Perioperative hemodynamic data and immediate postoperative outcome in two groups undergoing adrenalectomy were compared. 483 medical charts from urologic patients with tumors were analyzed. In the hypertensive (n = 168) group, 20 patients with suprarenal gland tumors were identified (phaeochromocytoma n = 11, other tumors n = 9). Demographic data, intraoperative consumption of fentanyl and phentolamine, preoperative hospital stay and postoperative ICU stay were compared. Mean arterial pressure (MAP) was registered on the day before surgery, before anesthetic induction, during surgery, and upon admission in the intensive care unit (ICU). Although BP values did not differ significantly on the day before anesthesia, before induction and during operation, significantly more antihypertensive drugs were used for BP regulation in phaeochromocytoma patients versus the other tumor group. The phaeochromocytoma group required significantly more fentanyl during surgery (370±87 vs. 242±35 µg; p = 0.04). MAP upon ICU admission was significantly lower (85.1 vs. 97.4, p = 0.02) after adrenalectomy in phaeochromocytoma patients versus the other tumor group. The postoperative MAP decreased significantly in the phaeochromocytoma group (21.51 mmHg, p = 0.005), whereas significant differences according to preoperative values were not observed in the other tumor group (5.5 mmHg, p = 0.416). Prolonged preoperative hospital stay (24.6 vs. 10.0 days, p = 0.005) and ICU stay were registered in the phaeochromocytoma group. Pheochromocytoma patients had more pronounced perioperative BP oscillations, needed more antihypertensive drugs, analgesics and required prolonged hospital stay than patients with other adrenal tumors. Prolonged α-blockade may have contributed to these effects.

Pheochromocytoma as a catecholamine producing tumor: implications for clinical practice

Pheochromocytomas are catecholamine-producing tumors presenting with various clinical symptoms, but mostly with headache, sweating, palpitations and hypertension. If not properly diagnosed, secretion of catecholamines may lead to fatal cardiovascular consequences. Biochemical testing for pheochromocytoma should be performed not only in symptomatic subjects or in subjects with adrenal incidentaloma but also in subjects with a genetic predisposition for pheochromocytoma (multiple endocrine neoplasia type 2, Von Hippel-Lindau (VHL) syndrome, neurofibromatosis type 1 (NF 1)and mutations of succinate dehydrogenase (SDH) genes). Once a pheochromocytoma is proven, computed tomography (CT), magnetic resonance imaging (MRI) and functional imaging with [(123)I]-MIBG may be used for tumor localization. Adequate medical pre-treatment is essential for successful operation which is performed in most cases by laparoscopy. After tumor removal, further follow-up is necessary due to possible recurrence. Although prognosis after tumor resection is excellent, a significant proportion of pheochromocytomas recur, some as metastases. Thus, appropriate follow-up is mandatory.

Recent advances in the diagnosis and treatment of pheochromocytoma

Pheochromocytoma (PHEO) is considered to be a rare cause of hypertension. However, if left untreated, PHEOs may lead to fatal hypertensive crises during anesthesia and other stresses. The diagnosis of PHEO is therefore extremely important. A 24-hour blood pressure (BP) pattern per se might be of some diagnostic value due to frequently observed higher BP variability as well as an attenuated night-time BP decrease. So far, germline mutations in five genes have been identified to be responsible for familial PHEOs: the von Hippel-Lindau gene, which causes von Hippel-Lindau syndrome, the RET gene leading to multiple endocrine neoplasia type 2, the neurofibromatosis type 1 gene, which is associated with von Recklinghausen's disease and the genes encoding the B and D subunits of mitochondrial succinate dehydrogenase (SDHB, SDHD), which are associated with familial paragangliomas and PHEOs. Genetic analysis should be offered to those patients with confirmed PHEO who are 50 years old or younger. Plasma-free metanephrines or urinary fractionated metanephrines seem to have higher diagnostic values compared to plasma or urinary catecholamines for the biochemical diagnosis of PHEO. Imaging with (123)I-metaiodobenzylguanidine or (18)F-fluorodopamine PET, if available, are in addition to CT/MRI useful for the detection of multifocal/extra-adrenal forms. Appropriate pharmacologic treatment with subsequent laparoscopic extirpation of PHEO is usually successful in benign forms. There is, however, no convincingly effective mode of treatment in malignant PHEOs.

Characteristics of Blood Pressure in Pheochromocytoma

Pheochromocytomas are catecholamine-producing tumors arising from chromaffin cells. One of the most typical symptoms of the catecholamine-excess state is hypertension either in the sustained or paroxysmal form, and its severity does not depend on the level of circulating catecholamines. On the other hand, hypertension in pheochromocytoma is very often characterized by the amelioration or even inversion of the circadian blood pressure rhythm. In some subjects, high circulating levels of catecholamines lead to the enhanced blood pressure variability. One possible explanation for such blood pressure variability is the desensitization of the catecholamine receptors due to high levels of circulating catecholamines.

Catecholamine-Secreting Metastatic Carcinoid as Differential Diagnosis in Pheochromocytoma: Clinical, Laboratory, and Imaging Clues in the Search for the Lurking Neuroendocrine Tumor (NET)

Catecholamine-secreting metastatic carcinoid should be considered in differential diagnosis of malignant pheochromocytoma. Paroxysmal functioning or hormonally silent gastroenteropancreatic neuroendocrine tumors (GEP NETs) require repeat biochemical measurements and sensitive anatomic and functional imaging studies overlapping those for malignant pheochromocytoma. This report presents clinical, laboratory, and radiologic findings in a patient presenting with heart rate variability; vasoactive headaches reactive to ethanol, tyramine and tryptophan; labile blood pressure; diaphoresis; diarrhea; abdominal pain; unexplained pancreatitis; joint pain; and paroxysmal flushing with pallor. GI studies (including endoscopic ultrasound) and multiple imaging modalities (including 2D CT, MRI with gadolinium, [18]FDG PET/CT, [123I]MIBG, and SRS [111In]Octreotide [OctreoScan]) were not diagnostic. 24-h BP, Holter and 30-day cardiac event monitors plus urinary biochemical studies consistently suggested catecholamine-synthesizing NET. NIH plasma metanephrines studies and [6]-[18F]Fluorodopamine PET ruled out malignant pheochromocytoma (pheo). Repeated studies showed persistently abnormal GEP NET biomarkers and urinary catecholamines. Capsule endoscopy revealed suspicious submucosal lesions throughout the small intestine. Dual-phase 64-slice multidetector computed tomography (MDCT) with 3D volumetric reconstruction of the abdomen and pelvis revealed multiple diffuse liver metastases and three extrahepatic lesions consistent with metastatic carcinoid. In combination, intensive biochemical testing repeated over time, dual-phase 64-slice MDCT with 3D image reconstruction and volume-rendering (VR) technique, and advanced radionuclide imaging are required to detect NETs' sporadic or paroxysmal functioning, rule out extra-adrenal pheochromocytoma, and localize and characterize metastatic carcinoid. If pheochromocytoma is ruled out, yet symptoms and biochemical markers for catecholamine excess are present, then carcinoid and other amine-precursor-uptake decarboxylation (APUD) tumors must remain in the differential diagnosis.