Cardiovascular effects of parathyroid hormone: a study in healthy subjects and normotensive patients with mild primary hyperparathyroidism

The preliminary study on cardiac structure and function in Chinese patients with primary hyperparathyroidism

PURPOSE

Recent evidences show that primary hyperparathyroidism (PHPT) patients have a high prevalence of cardiovascular diseases. However, the reported changes in cardiac status are inconsistent in previous studies. The present work evaluated the cardiac structure and function in PHPT patients by echocardiography.

METHODS

PHPT patients and age- and sex-matched healthy controls were enrolled in this case-control study. Biochemical parameters were retrospectively collected from PHPT patients. Cardiac function and structure were assessed in all subjects using echocardiography.

RESULTS

A total of 153 PHPT patients and 51 age- and sex-matched healthy controls were enrolled in this study. The mean serum calcium and parathyroid hormone (PTH) levels in PHPT patients were 2.84 ± 0.28mmol/L and 206.9 (130.0, 447.5) pg/ml, respectively. Left ventricular ejection fraction (LVEF) and early to late mitral annular velocity (E/A) were significantly lower in PHPT patients than in healthy controls (68.2 ± 6.0 vs. 70.7 ± 16.7%, 1.0 ± 0.5 vs. 1.4 ± 0.5, respectively, p both < 0.05). The left ventricular mass index (LVMI) and the relative wall thickness (RWT) were not significantly different between the two groups. However, the difference in LVEF between PHPT patients without hypertension and diabetes and the control groups disappeared. The majority of PHPT patients had normal cardiac geometry; however, a proportion of them exhibited concentric remodeling (normal LVMI, RWT≥0.42). Serum calcium, corrected calcium, ionized calcium and PTH were inversely related to E/A, whereas serum phosphorus and 24-hour urine calcium were positively related to E/A. Furthermore, biochemical parameters were not correlated with LVEF.

CONCLUSIONS

These findings demonstrate that PHPT patients exhibit diastolic cardiac dysfunction reflected by decreased E/A, as well as possible cardiac structural abnormalities. The serum calcium, phosphorus, and parathyroid hormone levels may influence cardiac structure and function.

Cardiac structural and functional abnormalities in primary hyperparathyroidism

PURPOSE

Studies on cardiac structural and functional abnormalities in primary hyperparathyroidism (PHPT) have yielded conflicting and inconsistent results. In this prospective case-control study, we sought to compare cardiac structure and function in symptomatic PHPT patients and controls.

METHODS

One hundred consecutive symptomatic PHPT patients and 113 matched controls underwent echocardiographic evaluation by the same operator.

RESULTS

Left ventricular mass index (LVMI) was significantly higher in patients as compared to controls, (median of 90.95 g/m² vs 86.5 g/m², p = 0.041). Patients had significantly lower early trans-mitral diastolic flow (E velocity) as compared to controls (57.13 ± 14.88 vs 64.76 ± 15.45 cm/s, p < 0.001). Patients also had significantly lower early to late mitral annular velocity (E/A) as compared to controls (0.98 ± 0.37 vs 1.10 ± 0.34, p 0.013). Patients had higher frequency of aortic valve calcification (29% vs 2.65%, p < 0.001), mitral annular calcification (23% vs. 4.42%, p < 0.001), myocardial and septal calcifications (25% vs none, p < 0.001) as compared to controls. Serum PTH, calcium and uric acid significantly correlated with calcifications. Serum calcium showed a negative correlation with E/A ratio.

CONCLUSIONS

Symptomatic patients with PHPT have substantial cardiac structural and functional abnormalities. These abnormalities include elevated LVMI, diastolic dysfunction, and aortic valve, mitral annular, septal and myocardial calcifications. We strongly suggest and conclude that the evaluation of PHPT patients should not only include traditional end organs like bones and kidneys but also the cardiovascular system in the form of echocardiography to detect subclinical cardiac dysfunction so that the cardiovascular health of such patients can be optimized.

The Harder the Heart, the Harder It Breaks: A Case of Complete Atrioventricular Block Secondary to Tertiary Hyperparathyroidism

The appearance of first-degree atrioventricular block and mitral annulus calcification in an end-stage renal failure patient with elevated parathyroid hormone levels should raise the suspicion of metastatic cardiac calcification. Measures should be taken to normalize the parathyroid hormone, calcium, and phosphorus levels to limit the progression of atrioventricular block. Exploration or removal of parathyroid glands should be considered if heart block worsens. 

The Interplay Between the Renin-Angiotensin-Aldosterone System and Parathyroid Hormone

The renin-angiotensin-aldosterone system (RAAS) is the regulatory system by which renin induces aldosterone production. Angiotensin II (Ang II) is the main effector substance of the RAAS. The RAAS regulates blood pressure and electrolyte balance by controlling blood volume and peripheral resistance. Excessive activation of the RAAS is an important factor in the onset of cardiovascular disease and the deterioration of this disease. The most common RAAS abnormality is primary aldosteronism (PA). Parathyroid hormone (PTH) is a peptide secreted by the main cells of the parathyroid gland, which promotes elevated blood calcium (Ca²⁺) levels and decreased blood phosphorus (Pi) levels. Excessive secretion of PTH can cause primary hyperparathyroidism (PHPT). Parathyroidism is highly prevalent in postmenopausal women and is often associated with secondary osteoporosis. PA and PHPT are common endocrine system diseases. However, studies have shown a link between the RAAS and PTH, indicating a positive relationship between them. In this review, we explore the complex bidirectional relationship between the RAAS and PTH. We also point out possible future treatment options for related diseases based on this relationship.

Retinal micro-vascular and aortic macro-vascular changes in postmenopausal women with primary hyperparathyroidism

Aim of the study was to evaluate the micro and macro-vascular changes in patients with primary hyperparathyroidism (PHPT) compared to controls. 30 postmenopausal PHPT women (15 hypertensive and 15 normotensive) and 30 normotensive controls underwent biochemical evaluation of mineral metabolism and measurements of arterial stiffness by 24 hour ambulatory blood pressure monitoring. Retinal microcirculation was imaged by a Retinal Vessel Analyzer. PHPT patients also underwent bone mineral density measurements and kidney ultrasound. PHPT patients had higher mean calcium and parathyroid hormone values compared to controls. Evaluating macro-vascular compartment, we found higher values of 24 hours-systolic, diastolic blood pressure, aortic pulse wave velocity (aPWV) and aortic augmentation index (Aix) in hypertensive PHPT, but not in normotensive PHPT compared to controls. The eye examination showed narrowing arterial and venular diameters of retinal vessels in both hypertensive and normotensive PHPT compared to controls. In hypertensive PHPT, 24 hours systolic blood pressure was associated only with parathyroid hormone (PTH) levels (beta = 0.36, p = 0.04). aPWV was associated with retinal diameter (beta = -0.69, p = 0.003), but not with PTH. Retinal artery diameter was associated with PTH (beta = -0.6, p = 0.008). In the normotensive PHPT, only PTH was associated with retinal artery diameter (beta = -0.60, p = 0.01) and aortic AIx (beta = 0.65, p = 0.02). In conclusion, we found macro-vascular impairment in PHPT and that micro-vascular impairment is negatively associated with PTH, regardless of hypertension in PHPT.

Parathyroid hormone is related to QT interval independent of serum calcium in patients with coronary artery disease

BACKGROUND

Elevated serum parathyroid hormone (PTH) is associated with increased risk of cardiovascular death, including sudden cardiac death, in patients with and without parathyroid disease. In small studies, PTH levels have been associated with changes in cardiac conduction and repolarization. Changes in the corrected QT interval (QTc) in particular are thought to be mediated by the effect of PTH on serum calcium. There is limited evidence to suggest PTH may affect cardiac physiology independent of its effects on serum calcium, but there is even less data linking PTH to changes in electrical conduction and repolarization independent of serum calcium.

METHODS

ECG data were examined from the PULSE database-an observational cohort study designed to examine depression after acute coronary syndromes (ACS) at a single, urban American medical center. In all, 407 patients had PTH and ECG data for analysis.

RESULTS

The QTc was longer in patients with elevated PTH levels compared with those without elevated PTH levels (451 ± 38.6 ms vs. 435 ± 29.8 ms; p < .001). The difference remained statistically significant after controlling for calcium, vitamin D, and estimated glomerular filtration rate (p = .007). Inclusion of left ventricular ejection fraction in the model attenuated the association (p = .054), suggesting that this finding may be partly driven by changes in cardiac structure.

CONCLUSIONS

In one of the largest series to examine PTH, calcium, and QT changes, we found that elevated PTH is associated with longer corrected QT interval independent of serum calcium concentration in ACS survivors.

Effect of Parathyroidectomy Upon Left Ventricular Mass in Primary Hyperparathyroidism: A Meta-Analysis

CONTEXT

Primary hyperparathyroidism (PHPT) has been associated with increased left ventricular mass (LVM) in many studies. Most studies have been inadequately powered to assess the effect of parathyroidectomy (PTX) on LVM.

OBJECTIVE

The objective was to evaluate whether PTX has a benefit on LVM in patients with PHPT.

DATA SOURCES

Sources included PubMed, Medline, Cochrane Library, clinicaltrials.gov, review articles, and abstracts from meetings.

STUDY SELECTION

Eligible studies included prospective studies of PTX vs observation or PTX alone in patients with PHPT who had LVM measured by echocardiography.

DATA EXTRACTION

Two investigators independently identified eligible studies and extracted data. Random-effects models were used to obtain final pooled estimates.

DATA SYNTHESIS

Fifteen studies (four randomized controlled trials and 11 observational) of 457 participants undergoing PTX were included. PTX was associated with a reduction in LVM (crude Hedges gu -0.290 ± 0.070, 95% confidence interval [CI] -0.423 to -0.157) of 11.6 g/m(2) (12.5%) on average. Effect size estimates differed by study duration (P < .001), with improvements seen in shorter (≤ 6 mo) but not longer studies. There was a trend toward greater improvement in observational studies vs randomized controlled trials (P = .07), and both serum calcium and PTH were higher in the former. Using random-effects models, the estimated effect size remained significant (Hedges gu -0.250, 95% CI -0.450 to -0.050). Higher preoperative PTH but not calcium was associated with a greater decline in LVM (β = -.039, 95% CI -0.075 to -0.004).

CONCLUSION

PTX reduced LVM in PHPT, and higher preoperative PTH levels were associated with greater improvements. Because the benefit was limited to short-term studies and PHPT disease severity was not independent of study design, further work is needed to clarify the factors that influence the change in LVM and whether the benefit persists beyond 6 months after PTX. Although the clinical significance of the LVM improvement is unclear, these data indicate that PTH may underlie increased LVM in PHPT.

Just hypercalcaemia or acute ST elevation myocardial infarction? A review of hypercalcaemia-related electrocardiographic changes

In elderly patients presenting with confusion and recurrent falls, conditions including infection, acute stroke, acute coronary events and electrolyte abnormalities have to be strongly considered as diagnostic possibilities. ECG is a non-invasive test that often serves as a useful tool in suggesting the underlying electrolyte disturbance. However, ECG must be interpreted with caution as it can, at times, be misleading, as in this case of hypercalcaemia seen by us. We discuss the different ECG findings in hypercalcaemic situations.

Cardiac structure and functions in patients with asymptomatic primary hyperparathyroidism

BACKGROUND

The data about cardiovascular (CV) changes in patients with asymptomatic primary hyperparathyroidism (PHPT) are scarce.

AIM

The aim of this study is to compare cardiac structure and functions in patients with asymptomatic PHPT and controls by using tissue Doppler echocardiography.

SUBJECTS AND METHODS

Thirty-eight patients with asymptomatic PHPT and 31 sex- and age-matched controls with similar cardiac risk factors were evaluated.

RESULTS

There was no significant difference in ejection fraction (EF) between the patients and the controls [64±5.95 vs 62±3.25% (p=0.094)]. Left ventricular mass index (LVMI) was significantly higher in patients than controls [105.96 (66.45-167.24) vs 93.79 (64.25- 139.25) g/m2, p=0.014]. There was a significant correlation between LVMI and serum calcium (Ca) (r=0.240, p<0.005). Myocardial performance index (MPI) was significantly higher in patients than controls [0.49 (0.35-0.60) vs 0.39 (0.33-0.62), p<0.001]. There was positive correlation between theMPI and serumCa levels (r=0.505, p<0.001), parathyroid hormone (PTH) levels (r=0.464, p<0.001) and LVMI (r=0.270, p<0.005). When the normotensive patients and controls were evaluated, the difference between the groups remained statistically significant considering LVMI and MPI [109 (66.45-167.24) g/m2 vs 94.17 (64.25-75.10) g/m2, p=0.03; and 0.49 (0.35-0.60) vs 0.39 (0.33-0.62), p<0.01, respectively]. There were significant correlations between MPI and Ca (r=0.566, p<0.001), and PTH (r=0.472, p<0.001).

CONCLUSIONS

Our study results showed that cardiacmorphology and diastolic functions are altered in the patients with asymptomatic PHPT. High serum PTH and Ca levels may have an impact on these CV changes. Whether these subtle CV changes would affect cardiac systolic functions and mortality in patients with asymptomatic PHPT should be investigated in further prospective studies.

Serum vitamin D and parathyroid hormone in relation to cardiac structure and function: the ICELAND-MI substudy of AGES-Reykjavik

CONTEXT

Emerging evidence suggests that vitamin D and PTH may play a role in the development of cardiac diseases.

OBJECTIVE

We investigated whether 25-hydroxyvitamin D (25OHD) and PTH concentrations are cross-sectionally associated with cardiac structure and function using magnetic resonance imaging (MRI).

DESIGN, SETTING, AND PARTICIPANTS

ICELAND-MI is a substudy of the Age, Gene/Environment Susceptibility-Reykjavik Study, an older-aged community-dwelling cohort with oversampling of participants with diabetes (29%) and measurements between 2004 and 2007. Serum 25OHD concentrations were measured using an immunoassay (n = 992). Intact PTH concentrations were measured using a 2-site immunoassay (n = 203). We included 969 participants for this cross-sectional analysis (mean age 76 ± 5.3 years, 51% female). Mean 25OHD was 54.2 ± 25.5 nmol/L and the median PTH was 4.5 pmol/L (range 1.5-18).

MAIN OUTCOMES

MRI to measure cardiac structure and function was the main outcome.

RESULTS

The lowest 25OHD category (<25 nmol/L) compared with the highest category (≥75 nmol/L) was associated with a smaller left and right atrial area in unadjusted analyses; however, the associations became nonsignificant after adjustment for covariates. The highest PTH quartile compared with the lowest quartile was significantly associated with a 7.3 g (95% confidence interval 0.8, 13.8) greater left ventricular (LV) mass and a 5.1% (-9.1, -1.1) lower LV ejection fraction compared with the lowest PTH quartile in the fully adjusted model.

CONCLUSIONS

Serum 25OHD concentrations were not associated with MRI measures in an older white population. Higher PTH concentrations were associated with greater LV mass and lower systolic function and may point to a potential role for PTH as a determinant of cardiac remodeling.

Nontraditional manifestations of primary hyperparathyroidism

Classical primary hyperparathyroidism (PHPT) was previously a multisystemic symptomatic disorder not only with overt skeletal and renal complications but also with neuropsychological, cardiovascular, gastrointestinal, and rheumatic effects. The presentation of PHPT has evolved, and today most patients are asymptomatic. Osteitis fibrosa cystica is rarely seen today, and nephrolithiasis is less common. Gastrointestinal and rheumatic symptoms are not part of the clinical spectrum of modern PHPT. It remains unclear whether neuropsychological symptoms and cardiovascular disease, neither of which are currently indications for recommending parathyroidectomy (PTX), are part of the modern phenotype of PHPT. A number of observational studies suggest that mild PHPT is associated with depression, decreased quality of life, and changes in cognition, but limited data from randomized controlled trials (RCTs) have not indicated consistent benefits after surgery. The increased cardiovascular morbidity and mortality in severe PHPT has not been definitively demonstrated in mild disease, although there is some evidence for more subtle cardiovascular abnormalities, such as increased vascular stiffness, among others. Results from observational studies that have assessed the effect of PTX on cardiovascular health have been conflicting. The single RCT in this area did not demonstrate that PTX was beneficial. Despite recent progress in these areas, more data from rigorously designed studies are needed to better inform the clinical management of patients with asymptomatic PHPT.

Arterial Hypertension, Metabolic Syndrome and Subclinical Cardiovascular Organ Damage in Patients with Asymptomatic Primary Hyperparathyroidism before and after Parathyroidectomy: Preliminary Results

Background. Primary hyperparathyroidism (PHPT) is associated with high cardiovascular morbidity, and the role of calcium and parathyroid hormone is still controversial. Objective. To evaluate the prevalence and outcomes of metabolic syndrome, hypertension, and some cardiovascular alterations in asymptomatic PHPT, and specific changes after successful parathyroidectomy. Material and Methods. We examined 30 newly diagnosed PHPT patients (8 males, 22 females; mean age 56 ± 6 yrs), 30 patients with essential hypertension (EH) (9 males, 21 females; mean age 55 ± 4), and 30 normal subjects (NS) (9 males, 21 females: mean age 55 ± 6). All groups underwent evaluation with ambulatory monitoring blood pressure, echocardiography, and color-Doppler artery ultrasonography and were successively revaluated after one year from parathyroidectomy. Results. PHPT patients presented a higher prevalence of metabolic syndrome (38%) with respect to EH (28%). Prevalence of hypertension in PHPT was 81%, and 57% presented altered circadian rhythm of blood pressure, with respect to EH (35%) and NS (15%). PHPT showed an important myocardial and vascular remodelling. During follow-up in PHPT patients, we found significant reduction of prevalence of metabolic syndrome, blood pressure, and "non-dipping phenomenon." Conclusions. Cardiovascular and metabolic alterations should be considered as added parameters in evaluation of patients with asymptomatic PHPT.

Improvement of hypertension after parathyroidectomy of patients suffering from primary hyperparathyroidism

Background. Primary hyperparathyroidism (PHPT) is one of the most common endocrine conditions and is accompanied by hypertension and increased cardiovascular mortality. The purpose of this study was to evaluate the effect of parathyroidectomy on systolic and diastolic blood pressure (BP) in hypertensive patients with PHPT and whether hypertension occurs more frequently in PHPT than in control group. Methods. A total of 1020 patients with proved PHPT who underwent surgery were compared with with 1020 age, sex, BMI, and smoking status matched controls. We evaluated changes in serum calcium, parathyroid hormone (PTH), uric acid, and BP before and 6 months after surgery. Results. Parathyroidectomy corrected PHPT and resulted in a substantial fall in both mean systolic (150 ± 3.8 to 138 ± 3.6 mmHg) and mean diastolic pressures (97 ± 3 to 88 ± 2.8 mmHg) of the hypertensive subjects; P < .01. In these patients, PTH, calcium, and uric acid normalized. 726 patients from 1020 with PHPT (69.8%) were found to be hypertensive whilst only 489 (47.8%) from 1020 of our control group. Conclusion. Parathyroidectomy in hypertensive patients reduces systolic and diastolic BP. PHPT is accompanied by a variety of metabolic complications, which are a risk factor for hypertension, and parathyroidectomy can improve these metabolic complications.

Cardiac function in mild primary hyperparathyroidism and the outcome after parathyroidectomy

OBJECTIVE

Primary hyperparathyroidism (PHPT) is associated with cardiovascular morbidity. The extent of cardiovascular abnormalities in patients with mild-asymptomatic disease is unclear. Using sensitive echocardiographic methods, we compared cardiac structure and function in patients with mild PHPT and in healthy controls, and evaluated the changes after parathyroidectomy (PTX).

METHODS

In a prospective case-control design, we studied 51 PHPT patients without any cardiovascular risk factors/diseases and 51 healthy matched controls. Cardiac structure, and systolic and diastolic function were evaluated by echocardiography and Doppler tissue imaging (DTI). Blood pressure (BP) and heart rate were measured.

RESULTS

We observed no differences in systolic or diastolic function or in cardiac morphology between the PHPT patients and the age-matched healthy controls. The regional peak systolic myocardial velocities (S') measured with DTI decreased at all sites (P<0.05) after PTX (tricuspid annulus 14.23+/-1.85 to 13.48+/-1.79, septal 8.48+/-0.96 to 7.97+/-0.85, and lateral 9.61+/-2.05 to 8.87+/-1.63 cm/s, part of the mitral annulus). At baseline, systolic BP was higher in patients compared to controls (127.6+/-17.1 vs 119.6+/-12.6 mmHg, P<0.05). After PTX, both systolic (127.6+/-17.1 vs 124.6+/-16.6 mmHg, P<0.05) and diastolic (80.3+/-9.6 vs 78.4+/-8.6 mmHg, P<0.05) BP decreased.

CONCLUSIONS

Our results indicate that patients with PHPT without cardiovascular risk factors have a normal global systolic and diastolic function and cardiac morphology. BP and the systolic velocities were marginally reduced after PTX, but reflected the values of the control group. Our findings warrant further investigation of the clinical and prognostic significance of these possibly disease-related inotropic effects.

Cardiac structure and diastolic function in mild primary hyperparathyroidism

CONTEXT

Data on the presence, extent, and reversibility of cardiovascular disease in primary hyperparathyroidism (PHPT) are conflicting.

OBJECTIVE

To evaluate the heart in PHPT, we assessed cardiac structure and diastolic function in patients with mild PHPT compared with age- and sex-matched controls.

DESIGN

This was a case-control study.

SETTINGS

The study was conducted in a university hospital Metabolic Bone Diseases Unit.

PARTICIPANTS

Fifty-four men and women with PHPT and 76 controls without PHPT participated in the study.

OUTCOME MEASURES

We measured left ventricular mass index (LVMI), the presence of mitral annular calcification, the ratio of early to late diastolic mitral inflow velocities (E/A), and early diastolic velocity of the lateral mitral annulus using Doppler tissue imaging (tissue Doppler e').

RESULTS

Patients had mild disease with mean (+/-sd) serum calcium 10.5 +/- 0.5 mg/dl and PTH 96 +/- 45 pg/ml. LVMI and diastolic function were normal in PHPT. There was no difference in LVMI (98 +/- 23 vs. 96 +/- 24 g/m(2), P = 0.69) or the frequency of mitral annular calcification between PHPT cases and controls. Diastolic function variables (E/A and tissue Doppler e') were higher (better) in cases compared with controls, although both were within the reference range. PHPT patients with low E/A had higher serum PTH (121 +/- 36 vs. 89 +/- 46 pg/ml, P = 0.03) and calcium (10.8 +/- 0.4 vs. 10.5 +/- 0.5 mg/dl, P = 0.05) than those with normal values. Finally, we found LVMI to be inversely associated with serum 25-hydroxyvitamin D in PHPT (r = -0.29, P < 0.05). All findings persisted after adjustment for group differences in cardiovascular risk factors.

CONCLUSIONS

Patients with biochemically mild PHPT do not have evidence of increased left ventricular mass, diastolic dysfunction, or increased valvular calcifications. However, the data support an association between low vitamin D levels and the development of left ventricular hypertrophy in this disorder. Finally, the increased serum calcium and PTH levels in those with diastolic dysfunction suggest that disease severity may determine the presence of cardiac manifestations in PHPT.

Carotid vascular abnormalities in primary hyperparathyroidism

CONTEXT

Data on the presence, extent, and reversibility of cardiovascular disease in primary hyperparathyroidism (PHPT) are conflicting.

OBJECTIVE

This study evaluated carotid structure and function in PHPT patients compared with population-based controls.

DESIGN

This is a case-control study.

SETTING

The study was conducted in a university hospital metabolic bone disease unit.

PARTICIPANTS

Forty-nine men and women with PHPT and 991 controls without PHPT were studied.

OUTCOME MEASURES

We measured carotid intima-media thickness (IMT), carotid plaque presence and thickness, and carotid stiffness, strain, and distensibility.

RESULTS

IMT, carotid plaque thickness, carotid stiffness, and distensibility were abnormal in PHPT patients, and IMT was higher in patients than controls (0.959 vs. 0.907 mm, P < 0.0001). In PHPT, PTH levels, but not calcium concentration, predicted carotid stiffness (P = 0.04), strain (P = 0.06), and distensibility (P = 0.07). Patients with increased carotid stiffness had significantly higher PTH levels than did those with normal stiffness (141 +/- 48 vs. 94.9 +/- 44 pg/ml, P = 0.002), and odds of abnormal stiffness increased 1.91 (confidence interval = 1.09-3.35; P = 0.024) for every 10 pg/ml increase in PTH, adjusted for age, creatinine, and albumin-corrected calcium.

CONCLUSIONS

Mild PHPT is associated with subclinical carotid vascular manifestations. IMT, a predictor of cardiovascular outcomes, is increased. Measures of carotid stiffness are associated with extent of PTH elevation, suggesting that those with more severe PHPT may have impaired vascular compliance and that PTH, rather than calcium, is the mediator.

Presentation of asymptomatic primary hyperparathyroidism: proceedings of the third international workshop

BACKGROUND

At the Third International Workshop on Asymptomatic Primary Hyperparathyroidism (PHPT) in May 2008, recent data on the disease were reviewed. We present the results of a literature review on issues arising from the clinical presentation and natural history of PHPT.

METHODS

Questions were developed by the International Task Force on PHPT. A comprehensive literature search for relevant studies was reviewed, and the questions of the International Task Force were addressed by the Consensus Panel.

CONCLUSIONS

1) Data on the extent and nature of cardiovascular involvement in those with mild disease are too limited to provide a complete picture. 2) Patients with mild PHPT have neuropsychological complaints. Although some symptoms may improve with surgery, available data remain inconsistent on their precise nature and reversibility. 3) Surgery leads to long-term gains in spine, hip, and radius bone mineral density (BMD). Because some patients have early disease progression and others lose BMD after 8-10 yr, regular monitoring (serum calcium and three-site BMD) is essential in those followed without surgery. Patients may present with normocalcemic PHPT (normal serum calcium with elevated PTH concentrations; no secondary cause for hyperparathyroidism). Data on the incidence and natural history of this phenotype are limited. 4) In the absence of kidney stones, data do not support the use of marked hypercalciuria (>10 mmol/d or 400 mg/d) as an indication for surgery for patients. 5) Patients with bone density T-score -2.5 or less at the lumbar spine, hip, or distal one third radius should have surgery.

Cardiovascular aspects of primary hyperparathyroidism

Data concerning the cardiovascular manifestations of primary hyperparathyroidism (PHPT) are inconsistent, which is due, in part, to the decrease in disease severity over the last several decades. In areas where patients tend to be more symptomatic, data support the presence of cardiovascular findings including myocardial and vascular calcification as well as increased cardiovascular mortality. Data from the cohorts in whom the disease is characterized by mild hypercalcemia, suggest that clinically overt cardiovascular manifestations are unusual in PHPT. Recent data, however, support the presence of subtle cardiovascular manifestations in mild disease, such as changes in endothelial function as well as increased vascular stiffness and perhaps diastolic dysfunction. Left ventricular hypertrophy is a more consistent finding across a spectrum of disease severity, though this finding may be related to hypertension, which has long been associated with PHPT.

Evaluation of subclinical coronary atherosclerosis in mild asymptomatic primary hyperparathyroidism patients

OBJECTIVE

Although there is sufficient data supporting the increased cardiovascular risk in patients with advanced stage of primary hyperparathyroidism (pHPT), it is not clear whether same is valid for patients with subclinical forms of this disease. In this study we aimed to evaluate coronary atherosclerosis burden of asymptomatic pHPT patients by using tomographic coronary calcification scoring.

PATIENTS AND METHODS

Thirty-one mild asymptomatic pHPT patients (28 female, 3 male; mean age: 54.4 +/- 12.1 years) and 19 gender- and age-matched normotensive healthy controls (17 female, 2 male; mean age: 50.6 +/- 5.8) constituted our study population. Asymptomatic pHPT patients were subdivided according to presence of hypertension (19 hypertensive and 12 non-hypertensive patients). All subjects in study population underwent tomographic coronary calcification scoring by using 16-multidetector computed tomography (16-MDCT).

RESULTS

Median tomographic coronary calcification score was comparable between the whole group of pHPT patients [0.0 (Interquartile Range, IQR:18.70] and the controls [0.0 (IQR: 0.90). Median tomographic coronary calcification scores of pHPT patients with hypertension was 0.90 (IQR: 75.0) HU, whereas no calcification was noted in coronary arteries of normotensive pHPT patients. Calcification scores of hypertensive pHPT patients were significantly higher than both normotensive pHPT patients (P = 0.014) and controls (P = 0.046). There was no significant difference regarding calcification scores of normotensive pHPT patients versus controls. In the binary logistic regression model, only the presence of hyperlipidemia was found to be independently associated with presence of calcification on coronary arteries (relative risk 6.56, 95% CI 1.18-36.56, P = 0.032).

CONCLUSION

These results suggest that mild asymptomatic pHPT with serum calcium levels in the high-normal range does not constitute an independent risk factor for coronary atherosclerosis. The combined presence of classic cardiovascular risk factors determines the severity of coronary atherosclerosis in these patients.

Parathyroid hormone and the cardiovascular system

The classical actions of parathyroid hormone (PTH) are well recognized, but its effects on other target tissues, such as the cardiovascular system, are less appreciated. Several studies have evaluated the effects of PTH in patients with primary hyperparathyroidism in order to understand potential cardiovascular effects in terms of hypertension, cardiovascular mortality, left ventricular function, and endothelial function. We review these studies and evaluate the cellular mechanisms that may affect these outcomes.

Effect of hypoxia on parathyroid hormone in lactating and neonatal rats: interaction with halothane

Low oxygen in the blood (hypoxemia) may occur in the neonate or women in the postpartum period. Administration of inhalation anesthetic may be required in this period. The purpose of this study was to evaluate the effect of 7 d of hypoxia on the neonatal rat pup and lactating dam without or with acute halothane anesthesia on serum calcium and calciotropic hormones. Ionized calcium was not altered by hypoxia or halothane administration. Hypoxia from birth had no effect on serum parathyroid hormone (PTH) in 7-d-old rat pups (48+/-4 pg/mL). Halothane increased PTH in rat pups (74+/-8 pg/mL). The effect of halothane was not augmented in hypoxic pups. Hypoxia for 7 d had no effect on serum PTH in lactating dams (23+/-3 pg/mL). Halothane resulted in an increase in PTH (106+/-17 pg/mL). When halothane was administered to hypoxic lactating dams, a striking increase in serum PTH was observed (401+/-50 pg/mL). We hypothesize that halothane and hypoxia alter parathyroid gland function by a direct effect on cellular calcium dynamics. This interaction may have clinical significance in hypoxic patients requiring general anesthesia.