Insulin resistance is related to left ventricular hypertrophy in patients with polycystic kidney disease type 1

Echocardiographic Abnormalities in Autosomal Dominant Polycystic Kidney Disease (ADPKD) Patients

Cardiovascular abnormalities, such as left ventricular hypertrophy and valvular disorders, particularly mitral valve prolapse, have been described as highly prevalent among adult patients with autosomal dominant polycystic kidney disease (ADPKD). The present study aimed to assess echocardiographic parameters in a large sample of both normotensive and hypertensive ADPKD patients, regardless of kidney function level, and evaluate their association with clinical and laboratorial parameters. A retrospective study consisted of the analysis of clinical, laboratorial, and transthoracic echocardiograms data retrieved from the medical records of young adult ADPKD outpatients. A total of 294 patients (120 M/174 F, 41.0 ± 13.8 years old, 199 hypertensive and 95 normotensive) with a median estimated glomerular filtration rate (eGFR) of 75.5 mL/min/1.73 m² were included. The hypertensive group (67.6%) was significantly older and exhibited significantly lower eGFR than the normotensive one. Increased left ventricular mass index (LVMI) was seen in 2.0%, mitral valve prolapse was observed in 3.4%, mitral valve regurgitation in 15.3%, tricuspid valve regurgitation in 16.0%, and aortic valve regurgitation in 4.8% of the whole sample. The present study suggested that the prevalence of mitral valve prolapse was much lower than previously reported, and increased LVMI was not seen in most adult ADPKD patients.

A Systematic Review of Reported Outcomes in ADPKD Studies

Introduction

Methods

Results

Conclusion

The Pathophysiology of Left Ventricular Hypertrophy, beyond Hypertension, in Autosomal Dominant Polycystic Kidney Disease

Heart disease is one of the leading causes of death in autosomal dominant polycystic kidney disease (ADPKD) patients. Left ventricular hypertrophy (LVH) is an early and severe complication in ADPKD patients. Two decades ago, the prevalence of LVH on echocardiography in hypertensive ADPKD patients was shown to be as high as 46%. Recent studies using cardiac magnetic resonance imaging have shown that the prevalence of LVH in ADPKD patients may be lower. The true prevalence of LVH in ADPKD patients is controversial. There is evidence that factors other than hypertension contribute to LVH in ADPKD patients. Studies have shown that young normotensive ADPKD adults and children have a higher left ventricular mass index compared to controls and that the prevalence of LVH is high in patients with ADPKD whose blood pressure is well controlled. Polycystin-1 (PC-1) and polycystin-2 (PC-2) control intracellular signaling pathways that can influence cardiac function. Perturbations of PC-1 or PC-2 in the heart can lead to profound changes in cardiac structure and function independently of kidney function or blood pressure. PC-1 can influence mammalian target of rapamycin and mitophagy and PC-2 can influence autophagy, processes that play a role in LVH. Polymorphisms in the angiotensin-converting enzyme gene may play a role in LVH in ADPKD. This review will detail the pathophysiology of LVH, beyond hypertension, in ADPKD.

Cardiac involvement in patients with Autosomal Dominant Polycystic Kidney Disease and normal renal function after six years of follow-up

The aim of the follow-up study was to compare the changes of M-mode echocardiographic parameters in autosomal dominant polycystic kidney disease (ADPKD) patients and controls without renal failure during six years of observation and to explore the associations of these parameters with metabolic syndrome components and kidney function. We performed a follow-up examination in 37 ADPKD patients and 40 controls. Anthropometric parameters were measured and fasting venous blood sample from each patient was tested for glucose, insulin, C-peptide, HbA1c, creatinine, and urea concentrations. All subjects underwent standard two-dimensional M-mode echocardiography. Left ventricular hypertrophy (LVH) was diagnosed based on left ventricular mass index (LVMI) adjusted for body surface area (LVMI- -S, LVH-S) or for height (LVMI-H, LVH-H). The prevalence of LVH was significantly greater in ADPKD patients than in controls (35% vs. 10%, p=0.012) according to the ESH/ESC criteria from 2013, and (27.0% vs. 7.5%, p=0.032) according to criteria from 2017. In patients with ADPKD, no significant increase of the echocardiographic parameters was observed in the 6 years between the initial examination and the follow-up examination. Cardiac involvement in women with ADPKD occurs at an earlier stage of the disease than in men. In patients with ADPKD treated for hypertension in accordance with the 2013 ESH/ESC Guidelines the progression of LVH was not observed during the 6-year follow-up, despite the deterioration of renal function. Obesity, blood pressure and renal function do not affect LVMI changes.

Cardiac Involvement in Autosomal Dominant Polycystic Kidney Disease

Cardiovascular disorders are the main complication in autosomal dominant polycystic kidney disease (ADPKD). contributing to both morbidity and mortality. This review considers clinical studies unveiling cardiovascular features in patients with ADPKD. Additionally, it focuses on basic science studies addressing the dysfunction of the polycystin proteins located in the cardiovascular system as a contributing factor to cardiovascular abnormalities. In particular, the effects of polycystin proteins’ deficiency on the cardiomyocyte function have been considered.

Cardiac function assessed by myocardial deformation in adult polycystic kidney disease patients

Background

Patients with autosomal dominant polycystic kidney disease (ADPKD) have an increased risk of cardiovascular morbidity and mortality. Impaired left ventricular (LV) global longitudinal strain (GLS) can be a sign of subclinical cardiac dysfunction even in patients with otherwise preserved ejection fraction (EF). Transmitral early filling velocity to early diastolic strain rate (E/SRe) is a novel measure of LV filling pressure, which is often affected early in cardiac disease.

Methods

A total of 110 ADPKD patients not on dialysis were included in this prospective study. All patients underwent an extensive echocardiographic examination including two-dimensional speckle tracking. GLS and strain rates were measured. The distribution of GLS and E/SRe was determined and patient characteristics were compared by median levels of GLS (− 17.8%) and E/SRe (91.4 cm). Twenty healthy participants were included as control group.

Results

There was a significantly worse GLS in the ADPKD patients (mean: − 17.8 ± 2.5%) compared to the healthy controls (mean: − 21.9 ± 1.9%), p < 0.001. The same was true for E/SRe (mean: 10.0 ± 0.3 cm) compared to the control group (mean: 6.5 ± 0.3 cm), p < 0.001. In simple logistic regression, male gender (OR: 4.74 [2.10–10.71], p < 0.001), fasting glucose (odds ratio (OR) 1.05 [1.01–1.10], p = 0.024), htTKV (OR: 1.07 [1.01–1.13], p = 0.013), HDL cholesterol (OR: 0.97 [0.94, 0.996], p = 0.025), triglycerides (OR: 1.01 [1.00–1.02], p = 0.039), hemoglobin (OR: 1.50 [1.11–2.04], p = 0.009), and β-blocker use (OR: 1.07 [1.01, 1.13], p = 0.013) were all associated with higher GLS. After multivariate logistic regression with backward model selection, only male gender (OR: 5.78 [2.27–14.71], p < 0.001) and β-blocker use (OR: 14.00 [1.60, 122.51], p = 0.017) remained significant. In simple logistic regression models, BMI (OR: 1.11 [1.02–1.20], p = 0.015), systolic blood pressure (OR: 1.03 [1.00–1.06], p = 0.027) and β-blocker use (OR: 17.12 [2.15–136.20], p = 0.007) were associated with higher E/SRe - a novel measure of left ventricular filling pressure. After backward elimination, only β-blocker use (OR: 17.22 [2.16, 137.14], p = 0.007) remained significant.

Conclusion

Higher GLS and E/SRe are common in ADPKD patients, even in patients with preserved eGFR and normal left ventricular EF. GLS and E/SRe may aid in cardiovascular risk stratification in patients with ADPKD as they represent early markers of cardiac dysfunction.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1500-1) contains supplementary material, which is available to authorized users.

Clinical Manifestation, Management and Prognosis of Acute Myocardial Infarction in Autosomal Dominant Polycystic Kidney Disease

BACKGROUND/AIMS

Cardiovascular complications are the most common cause of death in individuals with autosomal dominant polycystic kidney disease (ADPKD), yet there is no substantial data concerning the clinical characteristics of acute myocardial infarction (AMI) in this population. This study thus aimed to investigate AMI in persons with ADPKD.

METHODS

A retrospective analysis of ADPKD patients admitted to our hospital over a 13 year period was conducted. Age and gender-matched control patients without ADPKD were also selected at a ratio of 1: 10.

RESULTS

A total of 52 ADPKD and 520 non-ADPKD patients were enrolled in the present study, with those in the former group exhibiting significantly poorer kidney function. The distribution of AMI types differed significantly between these two groups. The incidence of ST-segment elevation myocardial infarction (STEMI) was higher (75.0%) and the incidence of non-ST segment elevation myocardial infarction (NSTEMI) was lower (25.0%) in the ADPKD group. At the onset of AMI, sudden cardiac death (SCD) was more common in ADPKD patients (11.5% vs. 4.6%). In terms of risk factors, the occurrence of hypertension was greater in ADPKD patients (78.8% vs. 39.6%). With regard to subsequent management, ADPKD patients had a higher prevalence of triple-branch coronary lesions (21.1% vs. 11.2%), undergoing more coronary artery bypass grafting (CABG) (7.7% vs. 5.4%) and fewer percutaneous coronary interventions (PCI) (73.1% vs. 84.6%). Overall, ADPKD patients had higher rates of mortality (13.5% vs. 6.2%).

CONCLUSION

ADPKD patients with AMI suffer from more severe conditions and difficult therapies, resulting in a poorer prognosis.

Epicardial Fat Thickness in Patients with Autosomal Dominant Polycystic Kidney Disease

INTRODUCTION

Autosomal dominant polycystic kidney disease (ADPKD) is associated with early organ damage such as left ventricular hypertrophy and higher cardiovascular risk when compared to essential hypertension (EH). Epicardial adipose tissue (EAT) is a new cardiovascular risk factor, but its role and correlation with left ventricular mass (LVM) in ADPKD is unknown.

AIMS

we sought to investigate whether EAT is higher and related to LVM indexed by body surface area (LVMi) in hypertensive patients with ADPKD compared to those with EH.

METHODS

We performed ultrasound measurement of EAT thickness, LVM, LVMi, and left atrium size (left atrial volume indexed for body surface, LAVI) in 41 consecutive hypertensive patients with ADPKD, compared to 89 EH patients.

RESULTS

EAT was significantly higher in the ADPKD group in comparison to EH subjects (9.2 ± 2.9 mm vs. 7.8 ± 1.6 mm, p < 0.001), and significantly correlated with LVM, LVMi, and LAVI in the ADPKD group (r = 0.56, p = 0.005; r = 0.424, p = 0.022; and r = 0.48, p = < 0.001, respectively). Comparing EAT against body mass index, systolic blood pressure, and age, we found that EAT was the strongest predictor of LVMi (β = 0.42, p = 0.007).

CONCLUSION

Our data showed that EAT was higher in ADPKD patients than in EH subjects and independently correlated with LVMi. EAT measurement can be a useful marker for the cardiovascular risk stratification in ADPKD.

Early Markers of Cardiovascular Risk in Autosomal Dominant Polycystic Kidney Disease

BACKGROUND/AIMS

Cardiovascular disease is the most frequent cause of morbidity and mortality in autosomal dominant polycystic kidney disease (ADPKD) patients, often before the onset of renal failure, and the pathogenetic mechanism is not yet well elucidated. The aim of the study was to identify early and noninvasive markers of cardiovascular risk in young ADPKD patients, in the early stages of disease.

METHODS

A total of 26 patients with ADPKD and 24 control group, matched for age and sex, were enrolled, and we have assessed inflammatory indexes, mineral metabolism, metabolic state and markers of atherosclerosis and endothelial dysfunction (carotid intima media thickness (IMT), ankle brachial index (ABI), flow mediated dilation (FMD), renal resistive index (RRI), left ventricular mass index (LVMI)) and cardiopulmonary exercise testing (CPET), maximal O2 uptake (V'O2max), and O2 uptake at lactic acid threshold (V'O2@LT).

RESULTS

The ADPKD patients compared to control group, showed a significant higher mean value of LVMI, RRI, homocysteine (Hcy), Homeostasis Model Assessment-insulin resistance (HOMA-IR), serum uric acid (SUA), Cardiac-troponinT (cTnT) and intact parathyroid hormone (iPTH) (p<0.001, p<0.001, p<0.001, p<0.001, p<0.001, p=0.007, p=0.019; respectively), and a lower value of FMD and 25-hydroxyvitaminD (25-OH-VitD) (p<0.001, p<0.001) with reduced parameters of exercise tolerance, as V'O2max, V'O2max/Kg and V'O2max (% predicted) (p<0.001, p<0.001, p=0.018; respectively), and metabolic response indexes (V'O2@LT, V'O2 @LT%, V'O2@LT/Kg,) (p<0.001, p=0.14, p<0.001; respectively). Moreover, inflammatory indexes were significantly higher in ADPKD patients, and we found a positive correlation between HOMA-IR and C-reactive protein (CRP) (r=0.507, p=0.008), and a negative correlation between HOMA-IR and 25-OH-VitD (r=-0.585, p=0.002).

CONCLUSION

In our study, ADPKD patients, in the early stages of disease, showed a greater insulin resistance, endothelial dysfunction, inflammation and mineral metabolism disorders, respect to control group. Moreover, these patients presented reduced tolerance to stress, and decreased anaerobic threshold to CPET. Our results indicate a major and early cardiovascular risk in ADPKD patients. Therefore early and noninvasive markers of cardiovascular risk and CPET should be carried out, in ADPKD patients, in the early stages of disease, despite the cost implication.

Insulin resistance in chronic kidney disease: a systematic review

Insulin resistance (IR) is an early metabolic alteration in chronic kidney disease (CKD) patients, being apparent when the glomerular filtration rate is still within the normal range and becoming almost universal in those who reach the end stage of kidney failure. The skeletal muscle represents the primary site of IR in CKD, and alterations at sites beyond the insulin receptor are recognized as the main defect underlying IR in this condition. Estimates of IR based on fasting insulin concentration are easier and faster but may not be adequate in patients with CKD because renal insufficiency reduces insulin catabolism. The hyperinsulinemic euglycemic clamp is the gold standard for the assessment of insulin sensitivity because this technique allows a direct measure of skeletal muscle sensitivity to insulin. The etiology of IR in CKD is multifactorial in nature and may be secondary to disturbances that are prominent in renal diseases, including physical inactivity, chronic inflammation, oxidative stress, vitamin D deficiency, metabolic acidosis, anemia, adipokine derangement, and altered gut microbiome. IR contributes to the progression of renal disease by worsening renal hemodynamics by various mechanisms, including activation of the sympathetic nervous system, sodium retention, and downregulation of the natriuretic peptide system. IR has been solidly associated with intermediate mechanisms leading to cardiovascular (CV) disease in CKD including left ventricular hypertrophy, vascular dysfunction, and atherosclerosis. However, it remains unclear whether IR is an independent predictor of mortality and CV complications in CKD. Because IR is a modifiable risk factor and its reduction may lower CV morbidity and mortality, unveiling the molecular mechanisms responsible for the pathogenesis of CKD-related insulin resistance is of importance for the identification of novel therapeutic targets aimed at reducing the high CV risk of this condition.

The relation of anthropometric measurements and insulin resistance in patients with polycystic kidney disease

OBJECTIVE

To examine the frequency of insulin resistance (IR) and its relation with anthropometric measurements in patients with autosomal dominant polycystic kidney disease (ADPKD).

MATERIAL AND METHODS

Nonobese 82 patients with ADPKD and 58 age matched healthy controls were enrolled into the study. None of participants were diabetic or receiving renal replacement therapies (RRT). IR was determined by homeostasis model assessment of insulin resistance (HOMA-IR) formula. Tanita body composition analyzer was used for anthropometric measurements. Creatinine clearance of participant were assessed by the modification of diet in renal diseases (MDRD).

RESULTS

Patients with ADPKD had significantly higher level of urea and creatinine, microalbuminuria, and lower level of MDRD. Body fat distribution and HOMA-IR in both the groups were similar. Systolic and diastolic blood pressure of patients were higher than those of controls.

CONCLUSION

We failed to determine a higher frequency of IR among patients with ADPKD.

An Update on Intradialytic Cardiac Dysfunction

Cardiac dysfunction is a key factor in the high morbidity and mortality rates seen in hemodialysis (HD) patients. Much of the dysfunction is manifest as adverse changes in cardiac and vascular structure prior to commencing dialysis. This adverse vascular remodeling arises as a dysregulation between pro- and antiproliferative signaling pathways in response to hemodynamic and nonhemodynamic factors. The HD procedure itself further promotes cardiomyopathy by inducing hypotension and episodic regional cardiac ischemia that precedes global dysfunction, fibrosis, worsening symptoms, and increased mortality. Drug-based therapies have been largely ineffective in reversing HD-associated cardiomyopathy, in part due to targeting single pathways of low yield. Few studies have sought to establish natural history and there is no framework of priorities for future clinical trials. Targeting intradialytic cardiac dysfunction by altering dialysate temperature, composition, or ultrafiltration rate might prevent the development of global cardiomyopathy, heart failure, and mortality through multiple pathways. Novel imaging techniques show promise in characterizing the physiological response to HD that is a unique model of repetitive ischemia-reperfusion injury. Reducing HD-associated cardiomyopathy may need a paradigm shift from empirical delivery of solute clearance to a personalized therapy balancing solute and fluid removal with microvascular protection. This review describes the evidence for intradialytic cardiac dysfunction outlining cardioprotective strategies that extend to multiple organs with potential impacts on exercise tolerance, sleep, cognitive function, and quality of life.

Effects of insulin resistance on left ventricular hypertrophy in patients with CKD stage 1-3

BACKGROUND

Left ventricular hypertrophy (LVH) existed in patients with early stage chronic kidney disease (CKD). But whether insulin resistance (IR) exists in these patients and has some definite relationship with LVH, is unknown.

METHODS

Homeostatic model method was used for detecting homeostasis model assessment of insulin resistance (HOMA-IR) in 336 subjects including 286 patients with early stage CKD and 50 control subjects, and HOMA-IR and other clinical data in all subjects were obtained based on standard methods. Then, the relationship between LVH, IR and other relevant clinical data were analyzed.

RESULTS

IR and LVH existed in early stage CKD patients. The prevalence of LVH in patients with IR was significantly higher than those without, and patients with LVH had a higher prevalence of IR than those without. The patients with IR or LVH had lower levels of e-GFR, hemoglobin (Hb) and total cholesterol, while higher levels of blood urea nitrogen (BUN), serum creatinine (Scr), intact parathyroid hormone (iPTH), CRP and systolic blood pressure (SBP). HOMA-IR had positive correlations with left ventricular mass index (LVMI). HOMA-IR and LVMI had positive correlations with BUN, Scr, iPTH and CRP, but negative with e-GFR and Hb. Multiple linear stepwise regression analysis showed that e-GFR, FINS, Hb and SBP enter the regression equation. Binary unconditional logistic regression analysis indicated that the main risk factors for LVH were CKD and IR (P < 0.05, respectively).

CONCLUSION

Both IR and LVH existed in early stage CKD patients and were more severe with the development of CKD. IR had a significant correlation with LVH. Furthermore, decline of e-GFR, hypertension and anemia were also associated with both IR and LVH and may have some effects in the mechanism of IR on the development of LVH.

Hypertension and left ventricular hypertrophy in autosomal dominant polycystic kidney disease

Hypertension is a common problem in patients with autosomal dominant polycystic kidney disease affecting both renal and patient survival. Activation of the renin-angiotensin-aldosterone system due to cyst expansion and local renal ischemia has been proposed to play an important role in the development of hypertension in autosomal dominant polycystic kidney disease. Left ventricular hypertrophy, a major cardiovascular risk factor, is also common in patients with autosomal dominant polycystic kidney disease. Both hypertension and the activation of the renin-angiotensin-aldosterone system play a role in the development of left ventricular hypertrophy in these patients. Prospective randomized results indicate that aggressive control of blood pressure is important for the optimal reversal of left ventricular hypertrophy, thereby diminishing a major risk factor for cardiovascular morbidity and mortality of patients with autosomal dominant polycystic kidney disease. There is also substantial epidemiological support for aggressive control of blood pressure in slowing renal disease progression in autosomal dominant polycystic kidney disease patients. Blockade of the renin-angiotensin-aldosterone system should be the initial approach in the treatment of hypertension in these patients.

Extra-renal manifestations of autosomal dominant polycystic kidney disease (ADPKD): considerations for routine screening and management

Autosomal-dominant polycystic kidney disease (ADPKD) is a systemic disease, marked by progressive increase of bilateral renal cysts, resulting in chronic kidney disease (CKD) and often leading to end-stage renal disease (ESRD). Apart from renal cysts, patients often have extra-renal disease, involving the liver, heart and vasculature. Other less common but equally important extra-renal manifestations of ADPKD include diverticular disease, hernias, male infertility and pain. Extra-renal disease burden is often asymptomatic, but may result in increased morbidity and mortality. If the disease burden is significant, screening may prove beneficial. We review the rationale for current screening recommendations and propose some guidelines for screening and management of ADPKD patients.

Neutrophil-to-lymphocyte ratio, insulin resistance, and endothelial dysfunction in patients with autosomal dominant polycystic kidney disease

Endothelial dysfunction (ED), insulin resistance (IR), and inflammation are risk factors for increased cardiovascular morbidity and mortality in autosomal dominant polycystic kidney disease (ADPKD). ADPKD patients may have increased carotid intima-media thickness (CIMT) and decreased coronary flow velocity reserve (CFVR). The neutrophil-to-lymphocyte ratio (NLR) was introduced as a marker to determine inflammation in various disorders. We aimed to investigate the relationship between NLR and IR, CFVR, CIMT, and the left ventricular mass index (LVMI) in normotensive ADPKD patients. Twentynine ADPKD patients (age 38.8 ± 10.2 years; 8 men and 21 women) and 19 healthy controls (age 33.8 ± 7.4 years; 8 men and 11 women) were included in this cross-sectional study. CFVR was calculated with echocardiography as the ratio of hyperemic to baseline diastolic peak coronary flow velocities. CIMT was measured in the distal common carotid artery by using a 10-MHz linear echocardiography probe. HOMA-IR was calculated NLR was calculated as the ratio of the neutrophil and lymphocyte counts. Age, sex, body mass index, and levels of glucose, creatinine, low-density lipoprotein (LDL)-cholesterol, high-density lipoprotein (HDL)-cholesterol, triglycerides, C-reactive protein (CRP), microalbuminuria, and creatinine clearance were similar between ADPKD patients and healthy subjects. NLR, CIMT, LVMI, and HOMA-IR were significantly higher and CFVR values were significantly lower in patients with ADPKD compared to that in healthy subjects. NLR showed positive correlation with CIMT, HOMA, insulin, glucose, and HDL cholesterol levels, while it was inversely correlated with CFVR and albumin level in all subjects. In patients with ADPKD, NLR showed positive correlation with HDL cholesterol level and inverse correlation with LVMI and albumin level. NLR that was found to be increased in patients with ADPKD may be a readily available marker of inflammation and ED.

Hypertension in autosomal dominant polycystic kidney disease

Hypertension is common and occurs in a majority of autosomal dominant polycystic kidney disease (ADPKD) patients before the loss of kidney function. Hypertension relates to progressive kidney enlargement and is a significant independent risk factor for progression to ESRD. The pathogenesis of hypertension in ADPKD is complex and dependent on many factors that influence each other. Pkd1 and Pkd2 expression levels are highest in the major vessels and are present in the cilia of endothelial cells and in vascular smooth muscle cells. Decreased or absent polycystin 1 or 2 expression is associated with abnormal vascular structure and function. Pkd1/Pkd2 deficiency results in reduced nitric oxide (NO) levels, altered endothelial response to shear stress with attenuation in vascular relaxation. Ten percent to 20% of ADPKD children show hypertension and the majority of adults are hypertensive before any loss of kidney function. Cardiac abnormalities such as left ventricular hypertrophy and carotid intimal wall thickening are present before the development of hypertension in ADPKD. The activation of the renin-angiotensin-aldosterone system occurs in ADPKD because of decreased NO production as well as bilateral cyst expansion and intrarenal ischemia. With increasing cyst size, further activation of the RAAS occurs, blood pressure increases, and a vicious cycle ensues with enhanced cyst growth and hypertension ultimately leading to ESRD. The inhibition of the angiotensin aldosterone system is possible with angiotensin converting enzyme inhibitors and angiotensin receptor blockers. However, interventional studies have not yet shown benefit in slowing progression to renal failure in ADPKD. Currently, large multicenter studies are being performed to determine the beneficial effects of RAAS inhibition both early and late in ADPKD.

Renal volume, renin-angiotensin-aldosterone system, hypertension, and left ventricular hypertrophy in patients with autosomal dominant polycystic kidney disease

The relationship between renal volume and hypertension in autosomal dominant polycystic kidney disease (ADPKD) occurs in childhood. Hypertension is associated not only with increased kidney volume but also with significantly increased left ventricular mass index. Moreover, this increase in left ventricular mass index occurs in children who have ADPKD with borderline hypertension (75th to 95th percentile) and is prevented with angiotensin-converting enzyme inhibitor (ACEI) monotherapy. Progression from borderline to overt hypertension (> or =95th percentile) occurs during a 5-yr follow-up in approximately 50% of children with ADPKD and borderline hypertension. Renal cyst enlargement in ADPKD in adults is associated with stimulation of both the circulating and intrarenal renin-angiotensin-aldosterone system. In addition to hypertension, the resultant angiotensin in ADPKD is a pivotal factor in cyst proliferation and expansion, increased sympathetic and endothelin activity, oxidant injury, and fibrosis. There is a close correlation between the level of hypertension, left ventricular hypertrophy, deterioration of GFR, and the progressive enlargement of the cystic kidneys in adult ADPKD. Randomized clinical investigation indicates that ACEI and a BP goal of 120/80 mmHg are associated in a 7-yr study to reverse left ventricular hypertrophy. The effect of renin-angiotensin-aldosterone system inhibition with dual blockade, ACEI and angiotensin receptor antagonists, on renal volume and kidney function is under study in the Halt Progression of Polycystic Kidney Disease (HALT PKD) trial.

Cardiovascular abnormalities in autosomal-dominant polycystic kidney disease

Cardiovascular problems are a major cause of morbidity and mortality in patients with autosomal-dominant polycystic kidney disease (ADPKD). Hypertension is a common early symptom of ADPKD, and occurs in approximately 60% of patients before renal function has become impaired. Hypertension is associated with an increased rate of progression to end-stage renal disease and is the most important potentially treatable variable in ADPKD. Left ventricular hypertrophy, which is a powerful, independent risk factor for cardiovascular morbidity and mortality, also occurs frequently in patients with ADPKD. Both hypertension and left ventricular hypertrophy have important roles in cardiovascular complications in these individuals. Moreover, biventricular diastolic dysfunction, endothelial dysfunction, increased carotid intima-media thickness, and impaired coronary flow velocity reserve are present even in young patients with ADPKD who have normal blood pressure and well-preserved renal function. These findings suggest that cardiovascular involvement starts very early in the course of ADPKD. Intracranial and extracranial aneurysms and cardiac valvular defects are other potential cardiovascular problems in patients with ADPKD. Early diagnosis and treatment of hypertension, with drugs that block the renin-angiotensin-aldosterone system, has the potential to decrease the cardiovascular complications and slow the progression of renal disease in ADPKD.

Developments in the management of autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent life- threatening, hereditary disease. ADPKD is more common than sickle cell anemia, cystic fibrosis, muscular dystrophy, hemophilia, Down's syndrome, and Huntington's disease combined. ADPKD is a multisystemic disorder characterized by the progressive development of renal cysts and marked renal enlargement. Structural and functional renal deterioration occurs in ADPKD patients and is the fourth leading cause of end-stage renal disease (ESRD) in adults. Aside from the renal manifestations, extrarenal structural abnormalities, such as liver cysts, cardiovascular abnormalities, and intracranial aneurysms may lead to morbidity and mortality. Recent studies have identified prognostic factors for progressive renal impairment including gender, race, age, proteinuria, hematuria, hypertension and increased left ventricular mass index (LVMI). Early diagnosis and better understanding of the pathophysiology of the disease provides the opportunity to aggressivly treat hypertension with renin-angiotensin-aldosterone system inhibitors and thereby potentially reduce LVMI, prevent cardiovascular morbidity and mortality and slow progression of the renal disease.

Diastolic function in several stages of chronic kidney disease in patients with autosomal dominant polycystic kidney disease: a tissue Doppler imaging study

BACKGROUND

This study evaluates the prevalence of diastolic dysfunction (DD) in several stages of chronic kidney disease (CKD) in patients with autosomal dominant polycystic kidney disease (ADPKD).

METHODS

107 ADPKD patients performed echocardiographic and Doppler studies and a tissue Doppler imaging (TDI) study. Patients were divided in three groups: group 1, 57 patients with CKD stage I, group 2, 37 patients in stages II and III, and group 3, 13 patients with CKD stages IV and V (not on dialysis).

RESULTS

In transmitral Doppler, 1 patient in group 1 compared to 5 in group 2, and 4 in group 3 exhibited DD (p < 0.005); moreover, E/A ratio decreases progressively from group 1 to 3 (p < 0.0001). In TDI, DD was observed in 8 patients in group 1, 17 in group 2, and 8 in group 3 had DD (p < 0.001). Em velocity, the best TDI parameter for DD, correlated with age, renal function and blood pressure. When adjusted for age, increased left ventricular mass index and decreased renal function were independent risk factors of DD.

CONCLUSIONS

DD occurred progressively as renal function deteriorates in patients with ADPKD and this effect is independently related to age and blood pressure.

Tissue Doppler imaging in the evaluation of left ventricular function in young adults with autosomal dominant polycystic kidney disease

BACKGROUND

Hypertension and increased left ventricular mass index (LVMI) have been reported in patients with early stages of autosomal dominant polycystic kidney disease (ADPKD). Whether these abnormalities are associated with diastolic dysfunction in this stage remains to be established. The aim of the study is to evaluate diastolic function in young normotensive patients with ADPKD by using tissue Doppler imaging (TDI), the most sensitive method available to date.

METHODS

Thirty-two young clinically normotensive patients aged 21 to 30 years were compared with 23 controls with similar ages. Ambulatory blood pressure measurement (ABPM) was performed to confirm normal blood pressure. Subsequently, patients and controls underwent echocardiography using transmitral Doppler and TDI.

RESULTS

LVMI was greater in patients with ADPKD than controls (89.3 +/- 17.7 versus 77.6 +/- 15.9 g/m2; P < 0.02). No significant differences were found in transmitral Doppler and TDI results. When ABPMs were taken into account, 11 patients had mild hypertension and showed increased LVMI and decreased early diastolic peak velocity (E wave: 67.0 +/- 12.0 cm/s in hypertensive patients with ADPKD versus 81.4 +/- 3.3 cm/s in normotensive patients with ADPKD versus 79.3 +/- 2.9 cm/s in controls; P < 0.04) and decreased TDI peak early diastolic annular velocity (11.6 +/- 2.8 cm/s in hypertensive patients with ADPKD versus 13.2 +/- 1.6 cm/s in normotensive patients with ADPKD versus 13.4 +/- 1.6 in controls; P < 0.05).

CONCLUSION

Diastolic dysfunction is not a prominent sign in young normotensive patients with ADPKD.

Should we quantify insulin resistance in patients with renal disease?

Cardiovascular disease is a major cause of morbidity and mortality in dialysis patients. Vascular disease develops before the initiation of dialysis, and it is now recognized that chronic kidney disease (CKD) is an independent risk factor for cardiovascular disease. Death from cardiovascular disease is a more common endpoint of CKD than progression to dialysis. There are multiple mechanisms that contribute to the increased vascular risk of CKD, one of which is the presence of insulin resistance (IR). CKD is characterised by many features of the metabolic syndrome, and features of IR are also observed in dialysis and transplant patients. IR may be quantified by several different methods. One such method is homeostatic model assessment (HOMA) technique, which derives a measurement of IR from fasting plasma glucose and insulin concentrations. The HOMA index has been demonstrated to be an independent predictor of survival in dialysis patients. CKD is characterised by a chronic inflammatory response and abnormalities in the production and regulation of adipose tissue derived proteins, which may contribute to the development of IR. There are a range of interventions including diet and exercise programmes or medications that may influence IR; however, the impact of these interventions in the context of CKD has not been systematically evaluated.

Biventricular diastolic dysfunction in patients with autosomal-dominant polycystic kidney disease

BACKGROUND

Left ventricular diastolic dysfunction has been shown in patients with autosomal-dominant polycystic kidney disease (ADPKD). However, there is no study evaluating right ventricular functions in these patients.

METHODS

In the present study, diastolic functions of both ventricles in normotensive and hypertensive ADPKD patients with well-preserved renal function were investigated. Fifteen hypertensive and 16 normotensive patients with ADPKD with well-preserved renal function, 16 patients with essential hypertension, and 24 healthy subjects were included in the study. Conventional left and right ventricular echocardiographic measurements were performed in all subjects. Left and right ventricular functions were investigated both by myocardial performance index (MPI) [calculated by dividing the sum of isovolumic contraction time and isovolumic relaxation time (IVRT) by ejection time] and by tissue Doppler imaging (TDI).

RESULTS

Left ventricular deceleration time and IVRT were significantly prolonged in hypertensive patients with ADPKD compared with patients with essential hypertension and even in normotensive patients with ADPKD compared with healthy subjects. Left and right MPIs were significantly higher in patients with ADPKD compared with healthy subjects, showing systolic and diastolic dysfunction. Moreover, by using TDI, the peak early diastolic mitral annular velocity (Em) to peak late diastolic mitral annular velocity (Am) ratio and the peak early diastolic tricuspid annular velocity (Et) to peak late diastolic tricuspid annular velocity (At) ratio were decreased in patients with ADPKD, suggesting biventricular diastolic dysfunction.

CONCLUSION

Both hypertensive and normotensive patients with ADPKD show significant biventricular diastolic dysfunction, suggesting cardiac involvement very early in the course of ADPKD.