Management of heart failure and coronary artery disease in patients with chronic kidney disease

Practical approach to evaluate asymptomatic coronary artery disease in end-stage renal disease patients at the initiation of dialysis

The high prevalence of significant asymptomatic coronary artery disease (CAD) has been reported in patients with end-stage renal disease (ESRD) at the initiation of dialysis. However, the approach to evaluate asymptomatic CAD for these patients has not been established. The aim of this study is to assess the applicability of our practical approach at the initiation of dialysis. We prospectively enrolled 182 consecutive ESRD patients who initiated dialysis. After echocardiography as primary screening, pharmacologic stress thallium-201 scintigraphy and/or coronary angiography (CAG) were performed to diagnose CAD. The patients were classified into two groups: those with coronary artery stenosis by CAG (CAD+ group), those without coronary artery stenosis by CAG or with negative scintigraphy examination (CAD- group). Of the eligible 93 patients without the history of CAD, 22 patients were allocated to the CAD+ group (18 of 26 patients with abnormal echocardiography and 4 of 13 patients with positive scintigraphy examination) and 71 patients to the CAD- group. Patients were followed up for an average of 520 ± 304 days. The event-free survival rate of major adverse cardiac events was significantly lower in the CAD+ group than in the CAD- group (P < 0.001). There was no cardiovascular event including major adverse cardiac events, unstable angina, coronary revascularization or stroke in the CAD- group during the first year of dialysis. Patients without CAD diagnosed by our approach had favorable clinical outcomes. Our approach may be useful for screening of occult CAD in ESRD patients at the initiation of dialysis.

[Heart failure in haemodialysis patients: evaluation and treatment]

Cardiovascular diseases are the leading cause of death in patients on haemodialysis. Cardiovascular mortality rate in these patients is approximately 9% per year, with the highest prevalence of left ventricular hypertrophy, ischemic heart disease and congestive heart failure being the most frequent cardiovascular complications. Risk factors for cardiac failure include hypertension, disturbed lipid metabolism, oxidative stress, microinflammation, hypoalbuminemia, anaemia, hyperhomocysteinemia, and increased concentration of asymmetric dimethylarginine, increased shunt blood flow and secondary hyperparathyroidism. Diagnostic strategy for early detection of patients with increased risk for the development of asymptomatic disturbances of systolic and diastolic left ventricular function should include echocardiografic examination, tests for determining coronary vascular disease, as well as tests of myocardial function (BNP, Nt-proBNP). Early detection of patients with a high risk of congestive heart failure enables timely implementation of adequate therapeutic strategy to provide high survival rate of HD patients.

Vitamin C prevents DNA damage induced by renovascular hypertension in multiple organs of Wistar rats

The aim of this study was to investigate, through the single-cell gel (comet) assay, whether vitamin C is able to protect against renovascular hypertension-induced genotoxicity in multiple organs. A total of 32 male Wistar rats were divided into four groups: negative control (n = 6); animals treated with vitamin C (n = 6); hypertensive rats (n = 10) and hypertensive rats and treated with vitamin C (n = 10). Hypertension was induced as a result of partial obstruction of the left renal artery by means of a silver clip during 6 weeks. Vitamin C was administered at 150 mg/kg during 7 consecutive days before the end of the experimental period. The results showed that vitamin C was able to protect blood cells against hypertension-induced genotoxicity. Brain, liver and heart cells were also protected by vitamin C following hypertension-induced genotoxic damage. Regarding blood pressure, vitamin C reduced the hypertensive state. In conclusion, our results suggest that vitamin C can prevent hypertension-induced DNA damage in blood, liver, brain and heart cells as well as to normalize the blood pressure of rats.

Early angiography in patients with chronic kidney disease: a collaborative systematic review

BACKGROUND AND OBJECTIVES

In the general population, an early invasive strategy of routine coronary angiography is superior to a conservative strategy of selective angiography in patients who are admitted with unstable angina or non-ST segment elevation myocardial infarction (MI), but the effectiveness of this strategy in individuals with chronic kidney disease (CKD) is uncertain.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a collaborative meta-analysis with data provided by the main authors of identified trials to estimate the effectiveness of early angiography in patients with CKD. The Cochrane, Medline, and EMBASE databases were searched to identify randomized trials that compared invasive and conservative strategies in patients with unstable angina or non-ST MI. Pooled risks ratios were estimated using data from enrolled patients with estimated GFR <60 ml/min per 1.73 m(2).

RESULTS

Five randomized trials that enrolled 1453 patients with CKD were included. An early invasive strategy was associated with nonsignificant reductions in all-cause mortality, nonfatal MI, and a composite of death or nonfatal MI. The invasive strategy significantly reduced rehospitalization.

CONCLUSIONS

This collaborative study suggests that the benefits of an early invasive strategy are preserved in patients with CKD and that an early invasive approach reduces the risk for rehospitalization and is associated with trends of reduction in the risk for death and nonfatal re-infarction in patients with CKD. Coronary angiography should be considered for patients who have CKD and are admitted with non-ST elevation acute coronary syndromes.

Cardiovascular morbidity and mortality in patients treated with hemodialysis: Epidemiological analysis

Background/Aim. Cardiovascular diseases are the leading cause of death in patients treated with hemodialysis (HD). The annual cardiovascular mortality rate in these patients is 9%. Left ventricular (LV) hypertrophy, ischemic heart disease and heart failure are the most prevalent cardiovascular causes of death. The aim of this study was to assess the prevalence of traditional and nontraditional risk factors for cardiovascular complications, to assess the prevalence of cardiovascular complications and overall and cardiovascular mortality rate in patients on HD. Methods. We investigated a total of 115 patients undergoing HD for at least 6 months. First, a cross-sectional study was performed, followed by a two-year follow-up study. Beside standard biochemical parameters, we also determined cardiac troponins and echocardiographic parameters of LV morphology and function (LV mass index, LV fractional shortening, LV ejection fraction). The results were analyzed using the Student's t test and Mann-Whitney U test. Results. The patients with adverse outcome had significantly lower serum albumin (p < 0.01) and higher serum homocystein, troponin I and T, and LV mass index (p < 0.01). Hyperhomocysteinemia, anemia, hypertriglyceridemia and uncontrolled hypertension had the highest prevalence (86.09%, 76.52%, 43.48% and 36.52%, respectively) among all investigated cardiovascular risk factors. Hypertrophy of the LV was presented in 71.31% of the patients and congestive heart failure in 8.70%. Heart valve calcification was found in 48.70% of the patients, pericardial effusion in 25.22% and disrrhythmia in 20.87% of the investigated patients. The average annual overall mortality rate was 13.74%, while average cardiovascular mortality rate was 8.51%. Conclusion. Patients on HD have high risk for cardiovascular morbidity and mortality.

Is Chronic Kidney Disease Comparable to Diabetes as a Coronary Artery Disease Risk Factor?

BACKGROUND

Chronic kidney disease (CKD) is one of the known risk factors for coronary heart disease (CHD). Though electrocardiograms (ECGs) have limited accuracy in determining the true prevalence of CHD, we wondered whether CKD and diabetes mellitus (DM) controlled for hypertension (HTN), had similar prevalences of ECG abnormalities that could reflect underlying coronary heart disease.

METHOD

Data were collected for 5,942 men and women aged 30 to 69 years in the Tehran Lipid and Glucose Study (TLGS), a crosssectional phase of a large epidemiologic study first initiated in 1999. ECG findings of all subjects were coded according to Minnesota ECG coding criteria. The Whitehall criteria for abnormal ECG findings that could represent ischemia were utilized. Creatinine clearance (Crcl) was estimated using the Cockroft-Gault equation and diabetes was defined according to the American Diabetic Association (ADA) criteria. Subjects with moderate CKD and without DM were compared with the patients with DM without CKD. HTN prevalence was similar. The analysis was performed for all Whitehall ECG ischemia abnormalities combined, and separately for pathologic Q waves.

RESULTS

In spite of an overall similar prevalence of smoking, and a lower incidence of dyslipidemia and HTN, moderate CKD patients had a higher prevalence of Whitehall criteria abnormal ECG findings compared with the patients with DM. Over 19% of patients with CKD had abnormal ECG findings while 14.7% of diabetic patients had abnormal ECGs (P = 0.02). The prevalence of Q waves was 11.5% in patients with CKD and 10.8% in patients with DM. In an age-matched subgroup of patients with DM and no CKD, the prevalence of ECG abnormalities was 19.3%, similar to the patients with moderate CKD and no DM (19.7%) (P = 0.9). The prevalence of pathologic Q waves in an age-matched group was 11.45%, compared with 11.5%, respectively.

CONCLUSION

Moderate CKD is a major risk factor for the development of the Whitehall ECG criteria which have been associated with ischemic heart disease. The importance of CKD as a risk factor for ECG abnormalities is comparable with DM. Patients with moderate CKD probably are candidates for aggressive CHD risk modification.

Cardiovascular risk in chronic renal disease and transplantation prevention and management

Cardiovascular disease (CVD) is the single best predictor of mortality in patients with chronic kidney disease and in kidney transplant recipients. These populations are considered to be at extraordinarily high risk for CVD and its complications. On the other hand, renal dysfunction should be considered as a CVD risk factor. The management of CVD in patients with chronic kidney disease is a special challenge for clinicians. In this article, major risk factors for CVD are presented, as well as diagnosis of coronary artery disease, acute coronary syndromes, its treatment modalities (pharmacological therapy and coronary revascularisation procedures), and outcomes in patients with chronic renal failure and kidney allograft recipients.

Diastolic Dysfunction

Heart failure is a leading cause of hospital admissions in North America. Approximately half of patients with symptoms of heart failure have normal or minimally impaired systolic function and are therefore diagnosed, by exclusion, with diastolic dysfunction. The therapy of diastolic dysfunction to date is largely unsatisfactory. There have been few outcome-based clinical trials to guide clinicians, and most treatments have been empirically derived from the data from systolic heart failure studies. In general, acute management consists of central volume reduction with loop diuretics and long-acting nitrates. In some cases improvement in left ventricular filling can be achieved by reducing heart rate, usually with either beta blockers or calcium channel blockers. The role of digoxin is unclear and it should be used with caution. Theoretically, it has the capacity to further impair ventricular function, but one of the few trials in diastolic heart failure suggested that it improves symptoms and reduces hospitalization. Renin-angiotensin system blockade is a very attractive therapeutic avenue; angiotensin-converting enzyme inhibitors and angiotensin receptor blockers effectively reduce afterload, induce regression of left ventricular hypertrophy in excess of their blood pressure-lowering effect, and confer survival benefits to patients at high risk for cardiovascular death. Although the results of a recent trial using an angiotensin receptor blocker in patients with primarily diastolic heart failure were unimpressive, renin-angiotensin system blockade should still be considered because of its aforementioned benefits. The long-term management of these patients includes a careful assessment for and treatment of myocardial ischemia, treatment of hypertension, and reduction in left ventricular hypertrophy. For the treatment of ischemia, long-acting nitrates and calcium channel blockers may be particularly useful. The results of new trials in this area are expected soon, and hopefully therapy that directly targets the pathophysiologic pathways of this important disease is on the horizon.