Baroreflex failure following radiation therapy for nasopharyngeal carcinoma

Timmers, Henri J L M; Karemaker, John M.; Lenders, J. W. M.; Wieling, Wouter

doi:10.1007/bf02318378

Cited by 41 publications

(30 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4,7 However, we were unable to provoke an excessive sympathetic response by a cold pressor test, which may be present inpatients with the full-blown clinical syndrome of baroreflex failure. 4 …”

Section: Effect Of Bcbr On Baseline Msnamentioning

confidence: 85%

“…10 The acute phase of iatrogenic carotid sinus denervation is characterized by sympathoexcitation, which may persist for hours to days. 4,4,5,7,8 Unselective anesthetic deafferentiation of arterial and cardiopulmonary baroreceptors in humans was shown to cause a strong rise in MSNA accompanied by hypertension and tachycardia, which persisted during the nerve block. 3 In patient 1, an immediate onset of severe hypertension and tachycardia was observed after BCBR, which had gradually declined within 3 days.…”

Section: Effect Of Bcbr On Baseline Msnamentioning

confidence: 99%

“…Baroreflex control of both heart rate and sympathetic nerve activity were attenuated in patients as compared with control subjects [heart rate baroreflex sensitivity: 3.68Ϯ0. 4,6,7 and carotid endarterectomy. 8 The resulting clinical syndrome of baroreflex failure is characterized by recurrent bouts of unrestrained sympathetic excitation, manifesting as severe hypertension, headache, and diaphoresis.…”

mentioning

confidence: 99%

“…3 In addition, normal cardiac rhythmicity of MSNA is lost after baroreceptor denervation. Apart from experimental denervation, iatrogenic denervation of baroreceptors may occur as complication of bilateral carotid body tumor resection (BCBR), 4,5 neck or mediastianal irradiation, 4,6,7 and carotid endarterectomy. 8 The resulting clinical syndrome of baroreflex failure is characterized by recurrent bouts of unrestrained sympathetic excitation, manifesting as severe hypertension, headache, and diaphoresis.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Baroreflex Control of Muscle Sympathetic Nerve Activity After Carotid Body Tumor Resection

et al. 2003

Self Cite

View full text Add to dashboard Cite

Abstract-Bilateral carotid body tumor resection causes a permanent attenuation of vagal baroreflex sensitivity. We retrospectively examined the effects of bilateral carotid body tumor resection on the baroreflex control of sympathetic nerve traffic. Muscle sympathetic nerve activity was recorded in 5 patients after bilateral carotid body tumor resection (1 man and 4 women, 51Ϯ11 years) and 6 healthy control subjects (2 men and 4 women, 50Ϯ7 years). Baroreflex sensitivity was calculated from changes in R-R interval and muscle sympathetic nerve activity in response to bolus injections of phenylephrine and nitroprusside. In addition, sympathetic responses to the Valsalva maneuver and cold pressor test were measured. The integrated neurogram of patients and control subjects contained a similar pattern of pulse synchronous burst of nerve activity. Baroreflex control of both heart rate and sympathetic nerve activity were attenuated in patients as compared with control subjects [heart rate baroreflex sensitivity: 3.68Ϯ0. 4,6,7 and carotid endarterectomy. 8 The resulting clinical syndrome of baroreflex failure is characterized by recurrent bouts of unrestrained sympathetic excitation, manifesting as severe hypertension, headache, and diaphoresis. The findings of excessive rises in plasma catecholamines during these attacks and of exaggerated pressor responses to cold and mental stress in these patients suggest the loss of baroreflexmediated inhibition of efferent sympathetic nerve activity. 4,6 In a previous study, we have demonstrated that although BCBR elicits the full-blown syndrome of baroreflex failure only in a minority of patients, 9 baroreflex control of heart rate is impaired and blood pressure variability is increased in the long term after BCBR. 9,10 Whether BCBR also affects baroreflex control of sympathetic outflow has not yet been established in humans.The aim of this study was to examine the chronic effects of BCBR on the baroreflex control of sympathetic nerve activity. In this cross-sectional, retrospective study of patients with BCBR and age-matched healthy control subjects, sympathetic baroreflex sensitivity was calculated from MSNA responses to (de-)activation of baroreceptors by phenylephrine and nitroprusside bolus injections. In addition, MSNA responses to the Valsalva maneuver and cold pressor test were assessed. Medical Center Nijmegen, the Netherlands, were included in this study. Individual information on tumor size, additional tumor localizations, and surgical details of these 5 patients are shown in the Table. The median interval between the second operation and the study was 6.7 years (range, 4.4 to 20.3 years). Patients were free of diabetes and neurological, cardiovascular, and pulmonary disease. Six healthy subjects (2 men and 4 women) served as control subjects. Full medical history and physical examination including blood pressure measurements revealed no abnormalities. Groups were matched for age (BCBR: 51.2Ϯ10.8 versus control subjects: 50.0Ϯ6.5 years), body mass index (24.8Ϯ1.1 ve...

show abstract

Section: Effect Of Bcbr On Baseline Msnamentioning

confidence: 85%

Section: Effect Of Bcbr On Baseline Msnamentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Baroreflex Control of Muscle Sympathetic Nerve Activity After Carotid Body Tumor Resection

et al. 2003

Self Cite

View full text Add to dashboard Cite

show abstract

“…5 A common cause of baroreflex failure is extensive neck surgery and radiation therapy for cancers of the neck, which may damage baroreceptors or afferent baroreflex neurons. 5,8,9 In some patients, the bilateral loss results from repeated trauma to the neck. 7 Baroreflex failure has also been described in patients with the familial paraganglioma syndrome.…”

Section: Causes Of Baroreflex Failurementioning

confidence: 99%

Baroreflex Failure

et al. 2005

View full text Add to dashboard Cite

Abstract-The baroreflex receives less attention nowadays because most students of hypertension are convinced that faulty volume regulation by the kidneys is responsible for long-term blood pressure increases. However, unusual patients with bilateral destruction of the normal blood pressure-sensing mechanisms can develop profound chronic hypertension. We present 2 patients with baroreflex failure. Both had volatile hypertension with systolic readings up to 300 mm Hg documented over years. Both had muscle sympathetic nerve activity that was increased even while resting. Treating these patients was a stochastic challenge. The therapy is frequently based on medicines that are no longer commonly prescribed. Key Words: baroreflex Ⅲ sympathetic nervous system Ⅲ autonomic nervous system Ⅲ hypotension Ⅲ bradycardia T he arterial baroreflex buffers acute fluctuations in blood pressure that occur during posture, stress, or other maneuvers. When blood pressure rises, vascular distension is transduced into nervous electrical activity, triggering reflex parasympathetic activation and sympathetic inhibition. Heart rate is slowed and vascular resistance is decreased, buffering the increase in blood pressure. Conversely, baroreceptor activity decreases when blood pressure falls, producing a reflex-mediated increase in heart rate and peripheral resistance. Baroreceptor activity is reset during sustained increases in blood pressure so that in patients with essential hypertension, baroreceptor responsiveness is maintained. However, the resetting of the baroreflex plays at least a permissive role in perpetuation of hypertension. Guyton argued that the baroreflex is responsible for the minute-to-minute regulation of blood pressure, but that the long-term blood pressure regulation is related to volume mechanisms adjusted by the kidneys. 1 However, faulty baroreflexes can occasionally influence long-term blood pressure regulation. An example is the condition of baroreflex failure. Such patients are a diagnostic challenge and a therapeutic nightmare. Case 1A 65-year-old woman was referred to our center for evaluation of possible baroreflex failure. Her chief symptom was volatile hypertension. The patient had a family history of arterial hypertension. Antihypertensive therapy was initiated at a young age and blood pressure readings were stable for many years. Twenty-two years before admission, a papillary thyroid cancer was diagnosed. She was successfully treated with thyroidectomy and local radiation followed by radioiodine treatment. Six years before admission, the patient experienced a neck trauma during a skiing accident. A left common carotid artery stenosis secondary to radiation injury was treated with angioplasty and stent implantation 4 years before admission. After the skiing accident, blood pressure became highly volatile. Systolic blood pressure values as high as 230 mm Hg had been recorded even during antihypertensive therapy with amlodipine, ramipril, spironolactone, metoprolol, and moxonidine. The hypertension was exacerba...

show abstract