Pathophysiology of severe primary graft dysfunction in orthotopic heart transplantation.

BACKGROUND: A series of insults on the donor heart result in pathophysiological changes that manifest as primary graft dysfunction (PGD) post-orthotopic heart transplantation. The objectives of this study were: (i) describe the pathophysiology of severe PGD using an established cardiovascular model; and (ii) the evolution of the pathophysiology during recovery from severe PGD. METHODS: Hemodynamic data from 20 consecutive patients with severe PGD (need for mechanical circulatory support, MCS) at baseline (T0), 6 h (T6) and "recovery" (explant of support), and 20 consecutive patients without severe PGD were used to model the pathophysiology using the cardiovascular model described by Burkhoff and Dickstein. RESULTS: There was a progressive (from T0 to T6) up- and leftward shift in the diastolic pressure-volume relationship, especially of the right ventricle (RV), resulting in reduced capacitance. RV end-systolic elastance (Ees) was significantly elevated in severe PGD but preload-recruitable stroke work (PRSW) was significantly lower compared to patients without severe PGD. "Recovery" (after liberation from MCS) was associated with improvement in RV Ees, chamber capacitance and PRSW, although they remained significantly lower than patients without severe PGD. CONCLUSION: Severe PGD of the dominant right heart failure phenotype is characterized by reduced chamber capacitance, increased "stiffness" and impaired contractility. Complete normalization was not required for successful weaning of MCS.

Mechanical circulatory support in the heart failure population.

PURPOSE OF REVIEW: Use of durable left ventricular assist devices (LVADs) has increased considerably in recent years because of the insufficient supply of donor hearts for cardiac transplantation and improvement in outcomes from refinements in technology. This review examines clinical utility of these devices and summarizes the most recent evidence supporting the use of LVAD therapy. RECENT FINDINGS: There continues to be significant advancements made in LVAD technology, which has resulted in improvements in the rates of adverse events and overall patient quality of life. Specifically, less invasive and improved surgical techniques have resulted in fewer incidence of pump thrombosis and stringent blood pressure management have been shown to significantly decrease stroke rates. SUMMARY: The continued advances in LVAD therapy have resulted in significant improvement in overall survival; however, complication rates remain relatively high. Future work will focus on improvements in adverse outcomes and ultimately the possibility that LVADs will be a viable alternative to transplantation in patients with end-stage heart failure.

Characterization of a resident population of adventitial macrophage progenitor cells in postnatal vasculature.

RATIONALE: Macrophages regulate blood vessel structure and function in health and disease. The origins of tissue macrophages are diverse, with evidence for local production and circulatory renewal. OBJECTIVE: We identified a vascular adventitial population containing macrophage progenitor cells and investigated their origins and fate. METHODS AND RESULTS: Single-cell disaggregates from adult C57BL/6 mice were prepared from different tissues and tested for their capacity to form hematopoietic colony-forming units. Aorta showed a unique predilection for generating macrophage colony-forming units. Aortic macrophage colony-forming unit progenitors coexpressed stem cell antigen-1 and CD45 and were adventitially located, where they were the predominant source of proliferating cells in the aortic wall. Aortic Sca-1(+)CD45(+) cells were transcriptionally and phenotypically distinct from neighboring cells lacking stem cell antigen-1 or CD45 and contained a proliferative (Ki67(+)) Lin(-)c-Kit(+)CD135(-)CD115(+)CX3CR1(+)Ly6C(+)CD11b(-) subpopulation, consistent with the immunophenotypic profile of macrophage progenitors. Adoptive transfer studies revealed that Sca-1(+)CD45(+) adventitial macrophage progenitor cells were not replenished via the circulation from bone marrow or spleen, nor was their prevalence diminished by depletion of monocytes or macrophages by liposomal clodronate treatment or genetic deficiency of macrophage colony-stimulating factor. Rather adventitial macrophage progenitor cells were upregulated in hyperlipidemic ApoE(-/-) and LDL-R(-/-) mice, with adventitial transfer experiments demonstrating their durable contribution to macrophage progeny particularly in the adventitia, and to a lesser extent the atheroma, of atherosclerotic carotid arteries. CONCLUSIONS: The discovery and characterization of resident vascular adventitial macrophage progenitor cells provides new insight into adventitial biology and its participation in atherosclerosis and provokes consideration of the broader existence of local macrophage progenitors in other tissues.

Caveolin-1 single-nucleotide polymorphism and arterial stiffness in non-dialysis chronic kidney disease.

BACKGROUND: Arteriosclerosis is an independent predictor of increased cardiovascular mortality in chronic kidney disease (CKD). Histologically it is characterized by hypertrophy and fibrosis of the arterial media wall leading to increased arterial stiffness and end-organ damage. Caveolin-1 acts as an intracellular signalling pathway chaperone in human fibrotic and vascular diseases. The purpose of this study was to assess the association between caveolin-1 (CAV1) single-nucleotide polymorphism (SNP) rs4730751 and arterial stiffness as measured by arterial pulse wave velocity (PWV) in an early-stage CKD cohort and in a cohort with more severe CKD. METHODS: Two prospectively maintained patient cohorts with non-dialysis CKD were studied: 144 patients in the Chronic Renal Impairment in Birmingham (CRIB) cohort and 147 patients in the Renal Impairment in Secondary Care (RIISC) cohort, with matched exclusion criteria and DNA sampling availability. At entry to each cohort database, each patient's initial arterial PWV was measured, as well as their anthropomorphic and biochemical data. CAV1 rs4730751 SNP genotyping was performed using Taqman technology. RESULTS: The CAV1 rs4730751 SNP CC genotype was associated with lower arterial PWV in both CRIB early stage CKD patients [8.1 versus 8.6 m/s; coefficient -0.780 (-1.412, -0.149); P = 0.016] and RIISC more advanced stage CKD patients [8.7 versus 9.4 m/s; coefficient -0.695 (-1.288, -0.102); P = 0.022]; these relationships held following adjustment for other important confounders. CONCLUSIONS: This replicated study suggests potential utility of the studied CAV1 SNP as a genetic biomarker in CKD and a role for CAV1 in the development of arteriosclerosis in this setting. Further studies are warranted to further explore the basic science driving these clinical observations.

Comparison of magnetic resonance feature tracking for systolic and diastolic strain and strain rate calculation with spatial modulation of magnetization imaging analysis.

PURPOSE: To compare cardiovascular magnetic resonance-feature tracking (CMR-FT) with spatial modulation of magnetization (SPAMM) tagged imaging for the calculation of short and long axis Lagrangian strain measures in systole and diastole. MATERIALS AND METHODS: Healthy controls (n = 35) and patients with dilated cardiomyopathy (n = 10) were identified prospectively and underwent steady-state free precession (SSFP) cine imaging and SPAMM imaging using a gradient-echo sequence. A timed offline analysis of images acquired at identical horizontal long and short axis slice positions was performed using CMR-FT and dynamic tissue-tagging (CIMTag2D). Agreement between strain and strain rate (SR) values calculated using these two different methods was assessed using the Bland-Altman technique. RESULTS: Across all participants, there was good agreement between CMR-FT and CIMTag for calculation of peak systolic global circumferential strain (-22.7 ± 6.2% vs. -22.5 ± 6.9%, bias 0.2 ± 4.0%) and SR (-1.35 ± 0.42 1/s vs. -1.22 ± 0.42 1/s, bias 0.13 ± 0.33 1/s) and early diastolic global circumferential SR (1.21 ± 0.44 1/s vs. 1.07 ± 0.30 1/s, bias -0.14 ± 0.34 1/s) at the subendocardium. There was satisfactory agreement for derivation of peak systolic global longitudinal strain (-18.1 ± 5.0% vs. -16.7 ± 4.8%, bias 1.3 ± 3.8%) and SR (-1.04 ± 0.29 1/s vs. -0.95 ± 0.32 1/s, bias 0.09 ± 0.26 1/s). The weakest agreement was for early diastolic global longitudinal SR (1.10 ± 0.40 1/s vs. 0.67 ± 0.32 1/s, bias -0.42 ± 0.40 1/s), although the correlation remained significant (r = 0.42, P < 0.01). CMR-FT generated these data over four times quicker than CIMTag. CONCLUSION: There is sufficient agreement between systolic and diastolic strain measures calculated using CMR-FT and myocardial tagging for CMR-FT to be considered as a potentially feasible and rapid alternative.

Cardiovascular effects of sevelamer in stage 3 CKD.

Serum phosphate independently predicts cardiovascular mortality in the general population and CKD, even when levels are in the normal range. Associations between serum phosphate, arterial stiffness, and left ventricular (LV) mass suggest a possible pathophysiological mechanism, potentially mediated by the phosphaturic hormone fibroblast growth factor-23 (FGF-23). To what extent the phosphate binder sevelamer modulates these effects is not well understood. In this single-center, randomized, double-blind, placebo-controlled trial, we enrolled 120 patients with stage 3 nondiabetic CKD. After a 4-week open-label run-in period, during which time all patients received sevelamer carbonate, we randomly assigned 109 patients to sevelamer (n=55) or placebo (n=54) for an additional 36 weeks. We assessed LV mass and systolic and diastolic function with cardiovascular magnetic resonance imaging and echocardiography, and we assessed arterial stiffness by carotid-femoral pulse wave velocity. The mean age was 55 years, and the mean eGFR was 50 ml/min per 1.73 m(2). After 40 weeks, we found no statistically significant differences between sevelamer and placebo with regard to LV mass, systolic and diastolic function, or pulse wave velocity. Only 56% of subjects took ≥ 80% of prescribed therapy; in this compliant subgroup, treatment with sevelamer associated with lower urinary phosphate excretion and serum FGF-23 but not serum phosphate, klotho, vitamin D, or cardiovascular-related outcomes of interest. In conclusion, this study does not provide evidence that sevelamer carbonate improves LV mass, LV function, or arterial stiffness in stage 3 nondiabetic CKD.

Bleeding outcomes after routine transradial primary angioplasty for acute myocardial infarction using eptifibatide and unfractionated heparin: a single-center experience following the HORIZONS-AMI trial.

OBJECTIVES: We sought to (1) determine the bleeding rates after primary percutaneous coronary intervention (PPCI) in our institution, where the default strategy has been transradial (TR) access in combination with unfractionated heparin (UFH) plus eptifibatide, and (2) compare these with the outcomes of patients treated with bivalirudin in HORIZONS-AMI. BACKGROUND: HORIZONS-AMI demonstrated that in PPCI undertaken via the transfemoral route, routine use of bivalirudin was associated with lower bleeding rates and improved mortality compared to routine use of UFH plus glycoprotein IIb/IIIa inhibitor (GPI). METHODS: This was a single-center prospective registry of consecutive patients undergoing PPCI from January 2009 to August 2011 at the Queen Elizabeth Hospital Birmingham, UK. Thirty-day major bleeding was defined as per the HORIZONS-AMI criteria and also according to TIMI and GUSTO scales. RESULTS: Of the 432 consecutive patients, 350 fulfilled entry criteria for HORIZONS-AMI. In contrast with HORIZONS-AMI, these subjects were older (62.5 ± 13.7 yr vs. 59.8 ± 11.1 yr, P < 0.05) with a higher rate of cardiogenic shock (6.3% vs. 0.8%, P < 0.0001). Despite this higher risk population, the rate of major bleeding was favorable (3.7% [95% CI: 2.0-6.3%] vs. 4.9% [4.0-6.1%], P = 0.32). Similarly, TIMI major bleeding (2.0% [0.8-4.1%] vs. 3.1% [2.3-3.4%], P = 0.10) and GUSTO severe or life-threatening bleeding (0.6% [0.1-2.5%] vs. 0.4% [0.2-0.9%], P = 0.75) were comparable. CONCLUSIONS: Routine TR access for PPCI using UFH plus GPI is associated with a low 30-day rate of major bleeding equivalent to the bivalirudin arm of HORIZONS-AMI. Default transradial access for PPCI permits routine use of a GPI without the penalty of high bleeding rates.

The safety and tolerability of spironolactone in patients with mild to moderate chronic kidney disease.

AIM: Mineralocorticoid receptor blockade (MRBs) in combination with angiotensin converting enzyme (ACE) inhibitors and angiotensin-II receptor blockade (ARBs) improve prognostic markers of cardiovascular and renal disease in early stage chronic kidney disease (CKD). Concerns relating to the safety and tolerability of MRBs in CKD may limit their use in a non clinical trial setting. METHODS In the Chronic Renal Impairment in Birmingham II study, 115 patients with non-diabetic early stage CKD (eGFR 30-89ml/min/1.73m(2) ) received 25mg daily of spironolactone for 4 weeks before randomization to continuing treatment or placebo for a further 36 weeks. All patients were on ACE inhibitors and/or ARB therapy. Potassium and renal function were checked at weeks 1, 2, 4, 8, 16, 28 and 40. The incidence of hyperkalaemia, significant renal dysfunction (reduction eGFR ≥25%) and adverse effects was assessed. RESULTS: After 40 weeks of treatment the incidence of serious hyperkalaemia (K(+) ≥6.0mmol/L) was <1%. A potassium 5.5-5.9mmol/L occurred on ≥1 occasion over follow-up in 11 patients (nine on spironolactone) and was predicted by baseline potassium ≥5.0mmol/L and eGFR ≤45 ml/min/1.73m(2) . Over follow-up, three patients experienced significant renal dysfunction but no patients withdrew due to intolerance or side effects. Changes in potassium, eGFR and systolic blood pressure were most apparent in the first 4 eeks. CONCLUSION: Spironolactone was well tolerated in selected patients with early stage CKD. Strict monitoring over the first month of treatment followed by standard surveillance as for ACE inhibitors and ARBs is suggested.

A Critical Evaluation of Patient Pathways and Missed Opportunities in Treatment for Heart Failure.

BACKGROUND: Heart failure (HF) is a global problem responsible for significant morbidity and mortality. METHODS: This review describes the patient pathways and missed opportunities related to treatment for patients with HF. RESULTS: The contemporary management strategies in HF, including medical therapies, device therapy, transplant, and palliative care. Despite the strong evidence base for therapies that improve prognosis and symptoms, there remains a large number of patients that are not optimally managed. The treatment of patients with HF is highly influenced by those who are caring for them and varies widely across geographical regions. HF patients can be broadly classified into two key groups: those who have known HF, and those who are incidentally found to have reduced left ventricular systolic dysfunction or other cardiac abnormality when an echocardiogram is performed. While all patients are under the care of a general practitioner or family doctor, in other instances, non-cardiologist physicians, cardiologists, and specialist HF nurses-each will have varying levels of expertise in managing HF-are part of the broader team involved in the specialist management of patients with HF. CONCLUSIONS: There are many potential missed opportunities in HF treatment, which include general opportunities, medications, etiology-specific therapy, device therapy, therapies when initial treatments fail, and palliative care.

Serum phosphate but not pulse wave velocity predicts decline in renal function in patients with early chronic kidney disease.

BACKGROUND: The rate of decline in kidney function is a powerful predictor of cardiovascular risk in patients with chronic kidney disease (CKD). Serum phosphate and increased arterial stiffness are associated with elevated cardiovascular risk in CKD and the general population. We sought to determine whether serum phosphate and markers of arterial stiffness predict progression of renal dysfunction in patients with early CKD. METHODS: Two hundred and twenty-five patients with Stage II-IV CKD were prospectively followed up at University Hospital Birmingham. Serum phosphate was measured at baseline and arterial stiffness was determined through measurement of aortic pulse wave velocity (PWV) and augmentation index (AIx). Progression of renal dysfunction was defined as the slope of estimated glomerular filtration rate (eGFR) against time. We determined the associations between possible predictors and rate of progression and also examined a combined end point of start of dialysis or ≥ 25% decline in eGFR. RESULTS: Mean baseline eGFR was 43 ± 19 mL/min/1.73 m(2) and serum phosphate 1.22 ± 0.27 mmol/L. Median follow-up was 924 days. Serum phosphate independently predicted a greater decline in eGFR; a 1 mmol/L increment in serum phosphate was associated with a 0.34 mL/min/month steeper decline (P = 0.02). Brachial and aortic systolic pressure independently predicted the rate of renal function decline but aortic PWV and AIx had no significant influence. Forty-one patients (18%) reached the combined end point; serum phosphate was significantly higher in this group (1.32 ± 0.36 versus 1.19 ± 0.24 mmol/L, P = 0.04) and was an independent predictor for the combined end point. CONCLUSIONS: Serum phosphate independently predicts decline in renal function in early CKD. Further studies are required to determine the mechanisms involved and to investigate the potential benefits of phosphate lowering on preserving kidney function.

The role of echocardiography in percutaneous left atrial appendage occlusion.

Percutaneous device closure of the left atrial appendage (LAA) has been introduced in the last decade as a minimally invasive alternative treatment to long-term anticoagulation to reduce the risk of thrombo-embolism in patients with atrial fibrillation. Echocardiography is an essential tool at all stages of the procedure. Pre-procedural echocardiography is used to screen suitable candidates and to define LAA morphology and dimension; peri-procedural transoesophageal or intracardiac echocardiography has a major role in guiding, delivery, and deployment of the device, for screening of procedural complications and for assessing procedural success; and post-procedural echocardiography is important in the surveillance and monitoring of long-term outcome. This article aims to outline the role of echocardiography at each stage of LAA occlusion.

3-year follow-up of 100 consecutive coronary bifurcation lesions treated with Taxus stents and the crush technique.

OBJECTIVES: To determine the 3 year safety and efficacy of crush-stenting with paclitaxel-eluting stents. BACKGROUND: The optimum two-stent strategy for treatment of coronary bifurcation lesions is undetermined. Crush-stenting is advocated to minimize restenosis through complete circumferential stent coverage; long-term follow-up data are lacking. METHODS AND RESULTS: In a single center prospective registry, 100 consecutive patients with bifurcation lesions were treated with the Crush technique. The vast majority (93%) were true bifurcations, predominantly involving the left anterior descending and diagonal arteries. Technical success was 98%. Final kissing balloon dilatation, which became standard practice during the study, was attempted in 68 patients and successful in 51. Abciximab was used in all cases. There were no peri-procedural stent thromboses. Follow-up was 100% at 3 years. Symptom-driven target lesion revascularisation was 8% at 3 years. Cumulative 3-year major adverse cardiac events was 28% (7 cardiac deaths, 15 myocardial infarctions, 11 target vessel revascularisations). Absence of a final kissing inflation predicted repeat revascularisation but not death, infarction or stent thrombosis. Three probable stent thromboses occurred, of which two were very late. CONCLUSION: Where a two-stent bifurcation strategy is required, Crush-stenting with paclitaxel-eluting stents is safe and effective in the long-term. Failure to perform a final kissing dilatation increases the likelihood of revascularisation but not other adverse events.

Republished paper: Arterial stiffness in chronic kidney disease: causes and consequences.

Chronic kidney disease is associated with elevated cardiovascular risk, and heart failure and arrhythmias are the biggest causes of cardiovascular death in this population. Increased arterial stiffness is a hallmark of chronic kidney disease and is associated with adverse alterations in cardiac structure and function that may predispose to an increased risk of cardiovascular death. These changes are already apparent in early kidney disease, which is highly prevalent in the developed world. The mechanisms underlying increased arterial stiffness in chronic kidney disease are undoubtedly complex, but an understanding is paramount to enable the development of novel therapeutic strategies to prevent or reverse this pathophysiology and therefore reduce the cardiovascular disease burden in this high-risk cohort.

Infected thrombus compression of the right ventricular outflow tract in transposition of the great arteries.

We describe the first reported case of infected thrombus compression of the right ventricular outflow tract in a Rastelli patient as a complication of pregnancy. This case emphasizes the importance of cardiac magnetic resonance imaging and echocardiography in the assessment of patients with adult congenital heart disease prior to and during pregnancy.

Vasculogenic properties of adventitial Sca-1+CD45+ progenitor cells in mice: a potential source of vasa vasorum in atherosclerosis.

The cellular origins of vasa vasorum are ill-defined and may involve circulating or local progenitor cells. We previously discovered that murine aortic adventitia contains Sca-1+CD45+ progenitors that produce macrophages. Here we investigated whether they are also vasculogenic. In aortas of C57BL/6 mice, Sca-1+CD45+ cells were localised to adventitia and lacked surface expression of endothelial markers (<1% for CD31, CD144, TIE-2). In contrast, they did show expression of CD31, CD144, TIE-2 and VEGFR2 in atherosclerotic ApoE-/- aortas. Although Sca-1+CD45+ cells from C57BL/6 aorta did not express CD31, they formed CD31+ colonies in endothelial differentiation media and produced interconnecting vascular-like cords in Matrigel that contained both endothelial cells and a small population of macrophages, which were located at branch points. Transfer of aortic Sca-1+CD45+ cells generated endothelial cells and neovessels de novo in a hindlimb model of ischaemia and resulted in a 50% increase in perfusion compared to cell-free control. Similarly, their injection into the carotid adventitia of ApoE-/- mice produced donor-derived adventitial and peri-adventitial microvessels after atherogenic diet, suggestive of newly formed vasa vasorum. These findings show that beyond its content of macrophage progenitors, adventitial Sca-1+CD45+ cells are also vasculogenic and may be a source of vasa vasorum during atherogenesis.

Cardiovascular Effects of Unilateral Nephrectomy in Living Kidney Donors.

UNLABELLED: There is a robust inverse graded association between glomerular filtration rate (GFR) and cardiovascular risk, but proof of causality is lacking. Emerging data suggest living kidney donation may be associated with increased cardiovascular mortality although the mechanisms are unclear. We hypothesized that the reduction in GFR in living kidney donors is associated with increased left ventricular mass, impaired left ventricular function, and increased aortic stiffness. This was a multicenter, parallel group, blinded end point study of living kidney donors and healthy controls (n=124), conducted from March 2011 to August 2014. The primary outcome was a change in left ventricular mass assessed by magnetic resonance imaging (baseline to 12 months). At 12 months, the decrease in isotopic GFR in donors was -30±12 mL/min/1.73m(2). In donors compared with controls, there were significant increases in left ventricular mass (+7±10 versus -3±8 g; P<0.001) and mass:volume ratio (+0.06±0.12 versus -0.01±0.09 g/mL; P<0.01), whereas aortic distensibility (-0.29±1.38 versus +0.28±0.79×10(-3) mm Hg(-1); P=0.03) and global circumferential strain decreased (-1.1±3.8 versus +0.4±2.4%; P=0.04). Donors had greater risks of developing detectable highly sensitive troponin T (odds ratio, 16.2 [95% confidence interval, 2.6-100.1]; P<0.01) and microalbuminuria (odds ratio, 3.8 [95% confidence interval, 1.1-12.8]; P=0.04). Serum uric acid, parathyroid hormone, fibroblast growth factor-23, and high-sensitivity C-reactive protein all increased significantly. There were no changes in ambulatory blood pressure. Change in GFR was independently associated with change in left ventricular mass (R(2)=0.28; P=0.01). These findings suggest that reduced GFR should be regarded as an independent causative cardiovascular risk factor. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01028703.

Impact of renal function on survival after transcatheter aortic valve implantation (TAVI): an analysis of the UK TAVI registry.

OBJECTIVE: To determine the nature of the association between renal dysfunction and outcomes following transcatheter aortic valve implantation (TAVI) in all cases performed in the UK between 2007 and 2012. METHODS: The UK TAVI registry was established to report outcomes on all TAVI procedures performed within the UK. Data were collected prospectively on 3980 patients from 1 January 2007 until 31 December 2012. RESULTS: In total, 205 patients (5.5%) died during their admission. Moderate to advanced chronic kidney disease (CKD) (estimated glomerular filtration rate (eGFR) <45 mL/min/1.73 m(2)) was significantly associated with increased mortality, even after adjustment for risk factors (OR 1.45, 95% CI 1.03 to 2.05; p=0.04). For every 10 mL/min/1.73 m(2) decrease in eGFR, in-hospital mortality increased by 8.2% (95% CI 1.1% to 14.7%; p=0.03). In total 1119 patients (30.2%) died during the follow-up period (median 543 days). Moderate to advanced CKD (eGFR <45 mL/min/1.73 m(2)) was significantly associated with increased mortality, even after adjustment for risk factors (OR 1.36, 95% CI 1.17 to 1.58; p<0.001). For every 10 mL/min/1.73 m(2) decrease in eGFR, cumulative mortality increased by 4.4% (95% CI 1.2% to 7.5%; p=0.007). Preoperative kidney function and the need for preoperative dialysis treatment discriminated between patients who died and survived. However, predictive power was poor with none of the c-statistics being >0.6. CONCLUSIONS: Pre-procedural renal dysfunction is associated, in a graded fashion independently of dialysis status, with worse outcomes, including mortality in patients undergoing TAVI.

Endothelial nitric oxide synthase single nucleotide polymorphism and left ventricular function in early chronic kidney disease.

BACKGROUND: Chronic kidney disease (CKD) is associated with accelerated cardiovascular disease and heart failure. Endothelial nitric oxide synthase (eNOS) Glu298Asp single nucleotide polymorphism (SNP) genotype has been associated with a worse phenotype amongst patients with established heart failure and in patients with progression of their renal disease. The association of a cardiac functional difference in non-dialysis CKD patients with no known previous heart failure, and eNOS gene variant is investigated. METHODS: 140 non-dialysis CKD patients, who had cardiac magnetic resonance (CMR) imaging and tissue doppler echocardiography as part of two clinical trials, were genotyped for eNOS Glu298Asp SNP retrospectively. RESULTS: The median estimated glomerular filtration rate (eGFR) was 50 mls/min and left ventricular ejection fraction (LVEF) was 74% with no overt diastolic dysfunction in this cohort. There were significant differences in LVEF across eNOS genotypes with GG genotype being associated with a worse LVEF compared to other genotypes (LVEF: GG 71%, TG 76%, TT 73%, p = 0.006). After multivariate analysis, (adjusting for age, eGFR, baseline mean arterial pressure, contemporary CMR heart rate, total cholesterol, high sensitive C-reactive protein, body mass index and gender) GG genotype was associated with a worse LVEF, and increased LV end-diastolic and systolic index (p = 0.004, 0.049 and 0.009 respectively). CONCLUSIONS: eNOS Glu298Asp rs1799983 polymorphism in CKD patients is associated with relevant sub-clinical cardiac remodelling as detected by CMR. This gene variant may therefore represent an important genetic biomarker, and possibly highlight pathways for intervention, in these patients who are at particular risk of worsening cardiac disease as their renal dysfunction progresses.

Defining the natural history of uremic cardiomyopathy in chronic kidney disease: the role of cardiovascular magnetic resonance.

Chronic kidney disease (CKD) is an under-recognized, highly prevalent cardiovascular (CV) risk factor affecting 1 in 7 adults. Large epidemiological studies have clearly established a graded association between the severity of CKD and CV event rates. Although patients with end-stage renal disease who are undergoing dialysis are at greatest CV risk, the disease process is evident in the early stages of CKD with glomerular filtration rates as high as 75 ml/min/1.73 m(2). Indeed, these patients are at least 6 times more likely to die of CV disease than to reach end-stage CKD. Thus, the major impact of CKD on the population and the healthcare budget is not that of providing renal replacement therapy but the cost of death and disability from premature CV disease. Although end-stage CKD is characterized by a clustering of conventional atherosclerotic risk factors, it has little association with CV event rates. This is reflected in disproportionate levels of sudden cardiac death, heart failure, and stroke, rather than myocardial infarction. Thus it appears that nonatherosclerotic processes, including left ventricular hypertrophy and fibrosis, account for most of the excess CV risk. Over the past decade, the use of cardiac magnetic resonance in CKD has brought about an improved understanding of the adverse CV changes collectively known as uremic cardiomyopathy. The unique ability of cardiac magnetic resonance to provide a comprehensive noninvasive examination of cardiac structure and function, arterial function, myocardial tissue characterization (T1 mapping and inversion recovery imaging), and myocardial metabolic function (spectroscopy) is ideally suited to characterize the phenotype of CV disease in CKD and to provide insight into the mechanisms leading to uremic cardiomyopathy. Concerns relating to an association between gadolinium contrast agents and nephrogenic systemic fibrosis in dialysis recipients have led to the use of lower doses and lower-risk gadolinium agents that appear to minimize this risk.