A Randomized Trial on the Effect of Phosphate Reduction on Vascular End Points in CKD (IMPROVE-CKD).

BACKGROUND: Hyperphosphatemia is associated with increased fibroblast growth factor 23 (FGF23), arterial calcification, and cardiovascular mortality. Effects of phosphate-lowering medication on vascular calcification and arterial stiffness in CKD remain uncertain. METHODS: To assess the effects of non-calcium-based phosphate binders on intermediate cardiovascular markers, we conducted a multicenter, double-blind trial, randomizing 278 participants with stage 3b or 4 CKD and serum phosphate >1.00 mmol/L (3.10 mg/dl) to 500 mg lanthanum carbonate or matched placebo thrice daily for 96 weeks. We analyzed the primary outcome, carotid-femoral pulse wave velocity, using a linear mixed effects model for repeated measures. Secondary outcomes included abdominal aortic calcification and serum and urine markers of mineral metabolism. RESULTS: A total of 138 participants received lanthanum and 140 received placebo (mean age 63.1 years; 69% male, 64% White). Mean eGFR was 26.6 ml/min per 1.73 m2; 45% of participants had diabetes and 32% had cardiovascular disease. Mean serum phosphate was 1.25 mmol/L (3.87 mg/dl), mean pulse wave velocity was 10.8 m/s, and 81.3% had abdominal aortic calcification at baseline. At 96 weeks, pulse wave velocity did not differ significantly between groups, nor did abdominal aortic calcification, serum phosphate, parathyroid hormone, FGF23, and 24-hour urinary phosphate. Serious adverse events occurred in 63 (46%) participants prescribed lanthanum and 66 (47%) prescribed placebo. Although recruitment to target was not achieved, additional analysis suggested this was unlikely to have significantly affected the principle findings. CONCLUSIONS: In patients with stage 3b/4 CKD, treatment with lanthanum over 96 weeks did not affect arterial stiffness or aortic calcification compared with placebo. These findings do not support the role of intestinal phosphate binders to reduce cardiovascular risk in patients with CKD who have normophosphatemia. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: Australian Clinical Trials Registry, ACTRN12610000650099.

Effects of Arteriovenous Fistula Ligation on Cardiac Structure and Function in Kidney Transplant Recipients.

BACKGROUND: Cardiovascular morbidity and mortality remain high in recipients of a kidney transplant. The persistence of a patent arteriovenous fistula (AVF) after transplantation may contribute to ongoing maladaptive cardiovascular remodeling. The ability to reverse this maladaptive remodeling by ligation of this AVF is unknown. We conducted the first randomized controlled trial to evaluate the effect of AVF ligation on cardiac structure and function in stable kidney transplant recipients. METHODS: In this randomized controlled trial, kidney transplant recipients (>12 months after transplantation with stable graft function) were randomized to AVF ligation or no intervention. All participants underwent cardiac magnetic resonance imaging at baseline and at 6 months. The primary outcome was the change in left ventricular (LV) mass. Secondary outcomes included changes in LV volumes, left and right atrial areas, LV ejection fraction, NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels, cardiac output/index, brachial flows (ipsilateral to AVF), and pulmonary artery velocity. RESULTS: A total of 93 patients were screened, of whom 64 met the inclusion criteria and were randomized to the AVF ligation (n=33) or control (n=31) group. Fifty-four participants completed the study: 27 in the AVF ligation group and 27 in the control group. On the second cardiac magnetic resonance scan, a mean decrease of 22.1 g (95% CI, 15.0-29.1) was observed in LV mass in the AVF ligation group compared with a small increase of 1.2 g (95% CI, -4.8 to 7.2) in the control group ( P<0.001). Significant decreases in LV end-diastolic volumes, LV end-systolic volumes, cardiac output, cardiac index, atrial volumes, and NT-proBNP were also seen in the AVF closure group ( P<0.01). No significant changes were observed in LV ejection fraction ( P=0.93) and pulmonary artery velocity ( P=0.07). No significant complications were noted after AVF ligation. No changes in estimated glomerular filtration rate or systolic and diastolic blood pressures were observed between cardiac magnetic resonance scans. CONCLUSIONS: Elective ligation of patent AVF in adults with stable kidney transplant function resulted in clinically significant reduction of LV myocardial mass. CLINICAL TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry URL: https://www.anzctr.org.au . Unique Identifier: ACTRN12613001302741.

The Impact of Arteriovenous Fistulae for Hemodialysis on the Cardiovascular System.

An arteriovenous fistula (AVF) is critical for the provision of optimal chronic hemodialysis. Its creation causes significant hemodynamic alterations in cardiovascular parameters, and can result in progressive left and right heart failure. Despite successful kidney transplantation, many patients retain a functional AVF indefinitely, which may contribute to ongoing adverse cardiovascular outcomes. A similar high risk:benefit ratio may exist in peritoneal dialysis patients with "backup" AVF.

Developing the future Indigenous health workforce: The feasibility and impact of a student-led placement programme in remote Indigenous communities.

OBJECTIVE: To describe and evaluate a programme where medical students designed and implemented Indigenous health placements for students with an interest in rural/Indigenous health. DESIGN, SETTING AND PARTICIPANTS: In 2011, a student-led programme at the University of Adelaide was set up to give medical students the opportunity to undertake outreach trips and clinical placements in remote Indigenous communities. Twenty-four medical students attended trips to remote communities between 2012 and 2014. Here we evaluate our programme using a single-arm experimental design. MAIN OUTCOME MEASURES: Responses to questionnaire items before and after attending an outreach placement, scored on 6-point Likert scales. RESULTS: Following their remote Indigenous health placement, participants expressed a significantly higher mean likelihood of working in an Indigenous community in the future (3.17 (2.69-3.64) versus 4.00 (3.65-4.35); P < 0.007). Furthermore, after their placement participants felt better prepared to work in Indigenous communities (mean 1.79 (1.44-2.14) versus 3.21 (2.88-3.54); P < 0.001). CONCLUSIONS: A placement programme initiated and run by medical students can provide meaningful exposure to Indigenous health. Implementation of this student-led model in other medical schools may encourage nationwide development of the Indigenous health workforce.

Nocardiosis presenting as a lung mass in a kidney transplant recipient.

Nocardiosis is a potentially life-threatening disease in renal transplant recipients. It is an uncommon infection with high lethality if left untreated. We report a case of a 67 year-old kidney transplant recipient who developed pulmonary nocardiosis and presented with pleural effusion along with an underlying lung mass, which was successfully treated with trimethoprim-sulphamethoxazole in conjunction with a reduction in immunosuppressive therapy. Five months later, graft function remains stable with complete regression of radiological abnormalities and absence of symptoms. Nocardiosis should be suspected in the presence of pulmonary symptoms in a transplant patient with unusual radiological presentation.

Beneficial cardiovascular remodeling following arterio-venous fistula ligation post-renal transplantation: a longitudinal magnetic resonance imaging study.

Despite improvements in survival following renal transplantation, high rates of cardiovascular morbidity and mortality remain. Persistence of arterio-venous fistulae (AVF) may contribute to maladaptive cardiovascular remodeling and poor health outcomes in this cohort. Utilizing recent advances in cardiovascular magnetic resonance imaging (CMR), we prospectively evaluated alterations in cardiac and vascular structure and function six months after elective ligation of AVF, following stable, successful renal transplantation. Eighteen subjects underwent CMR evaluation of cardiac structure and function, aortic distensibility and endothelial function prior to AVF ligation and at six months. At follow-up, while left ventricular ejection fraction was unchanged, mean cardiac output decreased by 15.6% (9.6 ± 2.9 L/min vs. 8.1 ± 2.3 L/min, p = 0.004) and left ventricular mass had regressed by 10% (166 ± 56 g vs. 149 ± 51 g, p = 0.0001). Significant improvements were also noted in right ventricular and biatrial structure and function. Aortic distensibility was unchanged at follow-up, but endothelial dependent vasodilatation had improved (2.5 ± 6.5% vs. 8.0 ± 5.9%, p = 0.04). Elective AVF ligation following successful renal transplantation is associated with improvements in left ventricular mass, right ventricular, and biatrial structure and function. Further randomized studies are warranted to determine the potential clinical improvement following AVF ligation in this cohort.

Post-transplant plasmablastic lymphoma of the skin.

Plasmablastic lymphoma (PBL) is a recently described rare variant of diffuse large B-cell lymphoma characterised by its aggressive nature and plasmacytic differentiation. It most frequently arises in the oral cavity of human immunodeficiency virus (HIV)-infected patients. However extra-oral involvement is becoming increasingly recognised, particularly in HIV-negative patients. We report a case of PBL presenting as multiple violaceous nodules and plaques on the leg of a HIV-negative patient, 13-years post-renal transplant. To date, 20 cases of PBL presenting in the skin have been reported. We review and compare the clinico-pathological features of these cases.

Calcium supplements lower bone resorption after renal transplant.

AIM: Bone loss in renal transplant (RT) patients is a problem that begins during end-stage kidney disease and persists after transplantation. Suppression of parathyroid hormone (PTH) may decrease bone loss and improve fracture rate. METHODS: A single-group prospective intervention study involving 30 patients was performed at a large RT unit. Investigations included dual-emission X-ray absorptiometry scan, vertebral X-ray, calcium absorption test, 24-h urinary calcium and serum measurements of total and ionized calcium, PTH, C-telopeptide cross-links (CTX), osteocalcin, alkaline phosphatase, 25 hydroxyvitamin D (25[OH]D), and 1,25-dihydroxyvitamin D3. Patients were given 500 mg elemental calcium daily for seven d, and serum measurements were repeated. RESULTS: Two-tailed Wilcoxon rank-sum test showed significant decreases in PTH (p<0.01) and CTX (p<0.01) after calcium load. Dietary calcium, mean calcium absorption, and urinary calcium excretion were below desirable levels. Mean 25 hydroxyvitamin D (25(OH)D) was low, but levels of 1,25-dihydroxyvitamin D3 were normal. Calcium absorption significantly correlated with change in PTH (p<0.001), baseline 25(OH)D (p<0.001), and mycophenolate dose (p=0.024). CONCLUSIONS: Calcium malabsorption is prevalent in RT recipients, contributing to bone destruction and compounded by poor dietary intake and low 25(OH)D. Calcium supplementation appears to help overcome this deficiency and acutely suppress PTH. Calcium may be an effective and inexpensive therapy for bone loss in RT recipients.

Long-Term Impact of Arteriovenous Fistula Ligation on Cardiac Structure and Function in Kidney Transplant Recipients: A 5-Year Follow-Up Observational Cohort Study.

Background: The long-term effects of arteriovenous fistula (AVF) ligation on cardiovascular structure following kidney transplantation remain uncertain. A prospective randomized, controlled trial (RCT) examined the effect of AVF ligation at 6 months on cardiovascular magnetic resonance imaging (CMR)-derived parameters in 27 kidney transplant recipients compared with 27 controls. A mean decrease in left ventricular mass (LVM) of 22.1 g (95% CI, 15.0 to 29.1) was observed compared with an increase of 1.2 g (95% CI, -4.8 to 7.2) in the control group (P<0.001). We conducted a long-term follow-up observational cohort study in the treated cohort to determine the evolution of CMR-derived parameters compared with those documented at 6 months post-AVF ligation. Methods: We performed CMR at long-term follow-up in the AVF ligation observational cohort from our original RCT published in 2019. Results were compared with CMR at 6 months postintervention. The coprimary end point was the change in CMR-derived LVM and LVM index at long-term follow-up from imaging at 6 months postindex procedure. Results: At a median of 5.1 years (interquartile range, 4.7-5.5 years), 17 patients in the AVF ligation group were studied with repeat CMR with a median duration to follow-up imaging of 5.1 years (IQR, 4.7-5.5 years). Statistically significant further reductions in LVM (-17.6±23.0 g, P=0.006) and LVM index (-10.0±13.0 g/m2, P=0.006) were documented. Conclusions: The benefit of AVF ligation on LVM and LVM index regression appears to persist long term. This has the potential to lead to a significant reduction in cardiovascular mortality.

Characterization of cardiac remodeling in a large animal "one-kidney, one-clip" hypertensive model.

OBJECTIVE: The aim of this study is to characterize cardiac remodeling in a large animal model of hypertension. METHODS: 23 sheep were subjected to unilateral nephrectomy followed by clamping of the remaining renal artery to 60% ("one kidney-one clip", 1K1C) 3 weeks later. Blood pressure (BP) was monitored invasively over 73+/-28 days. Cardiac function was assessed with magnetic resonance imaging and compared with 12 size-matched controls. Detailed atrial histopathological analysis was performed. RESULTS: In the 1K1C animals, BP rose from baseline to reach a plateau by 4 weeks (systolic BP: 107+/-12 to 169+/-27, diastolic BP: 71+/-10 to 118+/-29 mmHg, both p< 0.0001); cardiac hypertrophy was significant when compared with controls with increased left ventricular weight [left ventricular (LV)/body wt: 2.7+/-0.5 vs 2.1+/-0.2 g/kg, p=0.01] as well as bi-atrial enlargement (right atrial, RA: 22.9+/-4.9 vs 15.7+/-2.8g, p=0.003; left atrial, LA: 35.5+/-6.7 vs 20.9+/-4.1g, p=0.0003); cardiac magnetic imaging demonstrated significantly increased LA volumes (end-diastolic volume: 42.9+/-6.8 vs 28.7+/-6.3 ml, p< 0.0001) and reduced LA ejection fraction (24.1+/-3.6 vs 31.6+/-3.0%, p=0.001) while LV function was relatively preserved (42.3+/-4.7 vs 46.4+/-4.1%, p=0.1); degeneration and necrosis of atrial myocytes were evident with increased atrial lymphocytic infiltration and interstitial fibrosis. CONCLUSIONS: The ovine 1K1C model produces reliable and reproducible hypertension with demonstrable cardiac end-organ damage.

Endogenous plasma carnitine pool composition and response to erythropoietin treatment in chronic haemodialysis patients.

BACKGROUND: Anaemia is a common complication associated with haemodialysis and is usually managed by treatment with recombinant human erythropoietin (rHuEPO). However, many patients remain hyporesponsive to rHuEPO treatment despite adequate iron therapy. The effect of L-carnitine administration on rHuEPO dose and/or haematocrit in haemodialysis patients has been previously reported with equivocal results. This study examined the relationship between endogenous carnitine pool composition and rHuEPO requirements in long-term haemodialysis patients. METHODS: Pre-dialysis blood samples were collected from 87 patients and analysed for plasma L-carnitine and individual acylcarnitine levels by LCMS/MS. As an indication of rHuEPO responsiveness, erythropoietin resistance index (ERI) was calculated as rHuEPO dose/kg/week normalized for haemoglobin levels. RESULTS: A significant negative correlation between L-carnitine levels and ERI was found (P = 0.0421). All patients categorized as high ERI (>0.02 microg/kg/week/gHb) exhibited subnormal L-carnitine levels (<30 microM); conversely, patients with normal L-carnitine levels (>30 microM) displayed low ERI values (<0.02 microg/kg/week/gHb). More importantly, the ratio of non-acetyl acylcarnitines/total carnitine was significantly positively correlated with ERI (P = 0.0062). CONCLUSIONS: These data illustrate the relationship between carnitine levels and response to rHuEPO treatment in haemodialysis patients, in particular, the importance of the proportion of long-chain acylcarnitines within the plasma carnitine pool. This proportion may be more indicative of the response to L-carnitine supplementation than absolute L-carnitine levels alone.

End-stage renal failure is associated with impaired coronary microvascular function.

BACKGROUND: Cardiovascular disease is the leading cause of death in patients with chronic kidney disease. Studies investigating the disproportionate burden of cardiovascular disease have occurred predominantly in the peripheral vasculature, often used noninvasive imaging modalities, and infrequently recruited patients receiving dialysis. This study sought to evaluate invasive coronary dynamic vascular function in patients with end-stage renal failure (ESRF). PATIENTS AND METHODS: Patients referred for invasive coronary angiography prior to renal transplantation were invited to participate. Control patients were recruited in parallel. Baseline characteristics were obtained. Coronary diameter (via quantitative coronary angiography) and coronary blood flow (via Doppler Flowire) were measured; macrovascular endothelial-dependent and independent effects were evaluated in response to intracoronary acetylcholine infusion (10 and 10 mol/l) and intracoronary glyceryl trinitrate, respectively. Microvascular function was evaluated by response to adenosine and expressed as coronary flow velocity reserve. Mean values were compared. RESULTS: Thirty patients were evaluated: 15 patients with ESRF (mean age 52.1 ± 9, male 73%) and 15 control patients (mean age 53.3 ± 13, male 60%). Comorbidity profile, aside from ESRF, was well matched. Baseline coronary blood flow was similar between groups (101.6 ± 10.3 vs. 103.4 ± 9.1 ml/min, P = 0.71), as was endothelial-dependent response to acetylcholine (159.1 ± 16.9 vs. 171.1 ± 16.8 ml/min, P = 0.41). Endothelial-independent response to glyceryl trinitrate was no different between groups (14.3 ± 3.1 vs. 13.1 ± 2.3%, P = 0.73. A significantly reduced coronary flow velocity reserve was observed in the ESRF cohort compared to controls (2.34 ± 0.4 vs. 3.05 ± 0.3, P = 0.003). CONCLUSION: Patients with ESRF had preserved endothelial-dependent function however compared to controls, demonstrated significantly attenuated microvascular reserve. An impaired response to adenosine may not only represent a component of the pathophysiological milieu in patients with ESRF but may also provide a basis for the suboptimal diagnostic performance of vasodilatory stress in this population.

Lymphoproliferative disease after renal transplantation in Australia and New Zealand.

BACKGROUND: Lymphoproliferative disease is a common and serious complication of organ transplantation. It is well documented that the risk of its development increases with the level of immunosuppression. Less is known about its incidence, prevalence, timing, and prognosis. METHODS: The authors conducted a retrospective review of all patients with lymphoproliferative disease after renal transplantation documented in the Australia and New Zealand Dialysis and Transplant Registry from 1970 to March 2003. RESULTS: One hundred ninety-seven cases of lymphoproliferative disease occurred in 15,930 allografts in 13,516 recipients. There has been a steady increase in its incidence and prevalence each decade since 1970. Cases cluster into an early group (<2 years after transplantation) and a late group (5-10 years after transplantation). Risk factors include exposure to a calcineurin inhibitor, but there was no increased risk in those treated with anti-T-lymphocyte antibodies. Patient survival was poor: 51% at 1 year and 39% at 5 years. CONCLUSIONS: Lymphoproliferative disease is an increasingly common problem after renal transplantation, and the outcome is poor. Measures to reduce its incidence might include reduction of long-term immunosuppression exposure. Established disease has a high short-term mortality, and new treatment options, such as anti-B-lymphocyte monoclonal antibodies, should be aggressively pursued.

Impact of haemodialysis on individual endogenous plasma acylcarnitine concentrations in end-stage renal disease.

BACKGROUND: Patients with end-stage renal disease (ESRD) undergoing long-term haemodialysis exhibit low L-carnitine and elevated acylcarnitine concentrations. This study evaluated endogenous concentrations of an array of acylcarnitines (carbon chain length up to 18) in healthy individuals and ESRD patients receiving haemodialysis, and examined the impact of a single haemodialysis session on acylcarnitine concentrations. METHODS: Blood samples were collected from 60 healthy subjects and 50 ESRD patients undergoing haemodialysis (pre- and post-dialysis samples). Plasma samples were analysed for individual acylcarnitine concentrations by electrospray MS/MS. RESULTS: Of the 31 acylcarnitines, 29 were significantly (P<0.05) elevated in ESRD patients compared with healthy controls; in particular, C5 and C8:1 concentrations were substantially elevated. For acylcarnitines with a carbon chain length less than eight, plasma acylcarnitine concentrations decreased significantly over the course of a single dialysis session; however, post-dialysis concentrations invariably remained significantly higher than those in healthy subjects. Dialytic removal of acylcarnitines diminished once the acyl chain length exceeded eight carbons. CONCLUSIONS: The accumulation of acylcarnitines during long-term haemodialysis suggests that removal by haemodialysis is less efficient than removal from the body by the healthy kidney. Removal is significantly correlated to acyl chain length, most likely due to the increased molecular weight and lipophilicity that accompanies increased chain length.

Laparoscopic placement of peritoneal dialysis catheters: 7 years experience.

BACKGROUND: Since 1994 we have placed all peritoneal dialysis (Tenckhoff) catheters at our hospital laparoscopically using a technique that incorporates suture fixation into the pelvis. The purpose of this study was to determine the long-term outcome of this approach. METHOD: Perioperative and follow-up data for all patients undergoing placement of a peritoneal dialysis catheter at the Royal Adelaide Hospital were collected prospectively and managed on unit specific and hospital wide computerized databases. A total of 148 procedures were carried out in 123 patients from March 1994 to November 2001. Follow-up ranged from 3 to 68 months (median, 42 months). All procedures were undertaken or supervised by one surgeon, and catheters were routinely sutured into the pelvis at laparoscopy. RESULTS: There was no perioperative mortality in this series, and only one catheter could not be placed laparoscopically. This was in a patient with extensive intra-abdominal adhesions. Mean operative time was 27 min (range, 10-100 min), and mean postoperative stay was 2.8 days (range, 1-12 days). Seven (5%) patients experienced peri/postoperative haemorrhage, and four of these underwent surgical re-exploration. Twenty-five (17%) catheters are still used for dialysis. Thirty-four (23%) catheters were removed when the recipient received a subsequent renal transplant, and 42 (28%) patients died during follow-up. Forty-six (31%) patients required catheter revision or removal because of technical problems; 26 (18%) recurrent peritonitis or exit site infection; and 20 (14%) catheter blockage. Twenty-eight reinsertion procedures were carried out in 25 patients. Ten (7%) patients developed port site hernias at late follow-up, and required hernioplasty. Catheter migration leading to malfunction (poor drainage) occurred in eight (5%) patients only. CONCLUSIONS: Laparoscopic placement of peritoneal dialysis catheters is a safe and effective procedure. The majority of patients will dialyse successfully using this technique. Suturing the catheter tip into the pelvis is associated with a low rate of catheter migration.

The deleterious effects of arteriovenous fistula-creation on the cardiovascular system: a longitudinal magnetic resonance imaging study.

AIM: Arteriovenous fistula-formation remains critical for the provision of hemodialysis in end-stage renal failure patients. Its creation results in a significant increase in cardiac output, with resultant alterations in cardiac stroke volume, systemic blood flow, and vascular resistance. The impact of fistula-formation on cardiac and vascular structure and function has not yet been evaluated via "gold standard" imaging techniques in the modern era of end-stage renal failure care. METHODS: A total of 24 patients with stage 5 chronic kidney disease undergoing fistula-creation were studied in a single-arm pilot study. Cardiovascular magnetic resonance imaging was undertaken at baseline, and prior to and 6 months following fistula-creation. This gold standard imaging modality was used to evaluate, via standard brachial flow-mediated techniques, cardiac structure and function, aortic distensibility, and endothelial function. RESULTS: At follow up, left ventricular ejection fraction remained unchanged, while mean cardiac output increased by 25.0% (P<0.0001). Significant increases in left and right ventricular end-systolic volumes (21% [P=0.014] and 18% [P<0.01]), left and right atrial area (11% [P<0.01] and 9% [P<0.01]), and left ventricular mass were observed (12.7% increase) (P<0.01). Endothelial-dependent vasodilation was significantly decreased at follow up (9.0%±9% vs 3.0%±6%) (P=0.01). No significant change in aortic distensibility was identified. CONCLUSION: In patients with end-stage renal failure, fistula-formation is associated with an increase in cardiac output, dilation of all cardiac chambers and deterioration in endothelial function.

Antineutrophil cytoplasmic antibody-associated vasculitis with renal involvement: the evidence for treatment.

Antineutrophil cytoplasmic antibody-associated vasculitis is an autoimmune disease involving small to medium blood vessels. It is an uncommon illness, but can have devastating consequences, particularly on kidney function and other vital organs. Exciting progress has been made in the treatment of the disease largely because of international collaboration in randomised clinical trials. Patient survival has improved dramatically with advancements in disease diagnosis and medical treatment. The long-term morbidity from the disease, although improving, remains substantial with up to 10% of survivors requiring dialysis or kidney transplantation. Clinical trials are underway using more specifically targeted immunosuppressants in the hope to improve the long-term patient outcomes. Advancements are also being made in understanding the pathogenesis of the disease and this will further assist disease treatment and outcomes in the future.

Short-term hypertension is associated with the development of atrial fibrillation substrate: a study in an ovine hypertensive model.

BACKGROUND: Hypertension is frequently complicated by the development of atrial fibrillation (AF). However, the mechanisms of this link remain poorly understood. In addition, whether short-term hypertension can result in a substrate for AF is not known. OBJECTIVE: The purpose of this study was to characterize the atrial substrate predisposing to AF due to short-duration hypertension. METHODS: Sixteen sheep were studied: 10 had induced hypertension for 7 +/- 4 weeks via the "one-kidney, one-clip" model, and six were controls. Cardiac magnetic resonance imaging was used to assess functional changes. Open-chest electrophysiological study was performed using a custom-made 128-electrode epicardial plaque applied to both right (RA) and left atria (LA), including the Bachmann's bundle, to determine effective refractory periods (ERPs) and conduction velocity at four pacing cycle lengths from six sites. Tissue specimens were harvested for structural analysis. RESULTS: The hypertensive group demonstrated the following compared with controls: higher blood pressure (P <.0001), enlarged LA (P <.05), reduced LA ejection fraction (P <.05), uniformly higher mean ERP (P <.001), slower mean conduction velocity (P <.001), higher conduction heterogeneity index (P <.0001), greater AF inducibility (P = .03), and increased AF durations (P = .04). Picrosirius red staining of atrial tissues revealed increased interstitial fibrosis (P <.0001). There was also evidence of increased inflammatory cell infiltrates (P <.0001). CONCLUSION: Short-duration hypertension is associated with significant atrial remodeling characterized by atrial enlargement/dysfunction, interstitial fibrosis, inflammation, slowed/heterogeneous conduction, increased ERP, and greater propensity for AF.