Angiotensin converting enzyme inhibitors or angiotensin receptor blockers in nephropathy from type 2 diabetes

Potassium balance in dialysis patients

The advent of dialytic therapy has enabled nephrologists to provide life-saving therapy, but potassium balance continues to be an ever present challenge in the ESRD population. Although a small percent of patients are chronically hypokalemic, hyperkalemia is by far the most common abnormality in dialysis patients. It is associated with increased all-cause mortality, cardiovascular mortality, and arrhythmogenic death. Although alterations of the dialysis bath may decrease predialysis potassium, potassium baths <2 mEq/l are associated with a higher risk of sudden cardiac death. Studies show that patients are aware of the risks of hyperkalemia, but adherence to a low potassium diet is suboptimal. ACEI, ARBs, and spironolactone may cause slight increases in potassium even in anuric patients, requiring increased surveillance. Fludrocortisone and potassium binders have not been proven to be beneficial in lowering interdialytic potassium levels. Frequent hemodialysis may be a viable option, and studies of prophylactic placement of implantable cardioverter/defibrillators are underway.

Hypertension and microalbuminuria: the new detrimental duo

Excretion of albumin with urine (UAE) in small amounts, i.e. microalbuminuria (MAU), also referred to as "incipient nephropathy", has long been considered a marker of early nephropathy and increased cardiovascular risk in the specific setting of diabetes mellitus. However, numerous clinical studies found an association between MAU and other cardiovascular risk factors, target organ damage and risk of cardiovascular disease in clinical contexts different from diabetes and including arterial hypertension. The present article reviews the available evidence on the clinical value of MAU in subjects with primary hypertension. In these subjects, prevalence of MAU varied from about 4% to 46% across different studies and these differences may be explained by the huge intra-individual variability in UAE, discrepancies in the technique of measurement and different definitions of MAU. A direct and continuous association between UAE and blood pressure (BP) has been found in many studies. A continuous association between UAE and left ventricular mass has also been found in most studies. In contrast, it is not yet clear whether the association between UAE and other factors including age, gender, smoking, ethnicity, insulin resistance, lipids and obesity is independent or mediated by confounders, particularly BP. From a prognostic standpoint, several longitudinal studies showed an association between MAU and the risk of future cardiovascular disease. Of particular note, in some of these studies the incidence of major cardiovascular events progressively increased with UAE starting below the conventional MAU thresholds. Thus, besides being a direct risk factor for progressive renal damage, MAU can be considered a marker, which integrates and reflects the long-term level of activity of several other detrimental factors on cardiovascular system. Antihypertensive treatment reduces UAE and such effect may be detected after just a few days of treatment. Among available antihypertensive drugs, angiotensin-converting enzyme (ACE) inhibitors and the angiotensin II receptor antagonists seem to be superior to other antihypertensive drugs in reducing UAE. The dual blockade of the renin-angiotensin system with an ACE inhibitor and an angiotensin II receptor antagonist is a new and promising approach to control UAE in hypertensive patients. Determination of MAU is recommended in the initial work-up of subjects with primary hypertension.

The role of angiotensin II type 1 receptor blockers in the prevention and management of diabetes mellitus

Angiotensin II Receptor blockers (ARBs) are an important addition to the current range of medications available for treating a wide spectrum of diseases including cardiovascular diseases. Coronary heart disease (CHD) is the most common cause of death in the United Kingdom and worldwide. More importantly, the presence of the metabolic syndrome and the likelihood of diabetes mellitus taking on epidemic proportions in the years to come all threaten to maintain the mortality rate due to CHD. This review article focuses on the clinical studies that have helped define the trends in the usage of these agents in the prevention and treatment of diabetes mellitus and its complications and also explores possible mechanisms of action and future developments.

Percutaneous coronary interventions in the high-risk renal patient: strategies for renal protection and vascular protection

CKD is the most important factor in predict-ing adverse short- and long-term outcomes after PCI. Hence, the rationale for renal end-organ protection is based on chronic renal protection,avoidance of additive renal insults, and a comprehensive CIN prophylaxis. The pathogenesis of CIN goes beyond serum creatinine and involves a unique vascular pathobiology in which interrelates renal and CVD outcomes are interrelated. Attempts at PCI in patients with CKD and ESRD are high-risk procedures, but the risks involved seem to be warranted given comparative outcomes in conservatively treated patients. The benefits of short- and long-term vascular protective therapies in CKD patients have been confirmed, and these therapies are an important component of PCI care.

Intervention at lower blood pressure levels to achieve target goals in type 2 diabetes

BACKGROUND

Arterial hypertension greatly increases the risk of cardiovascular disease, renal insufficiency, and retinopathy in patients with type 2 diabetes. Epidemiological studies all document a reduced risk for the aforementioned consequences at a blood pressure (BP) lower than 130/80 mmHg. For this reason, lower target BPs are recommended by recent guidelines committees. A lower threshold BP for treatment, also proposed in guidelines, could facilitate the attainment of the recommended target BP. However, little data exist on the efficacy and safety of starting pharmacological therapy in type 2 diabetic patients exhibiting high-normal BP (HNBP) or the first stage of isolated systolic hypertension previously considered as borderline isolated systolic hypertension (BISH).

OBJECTIVE

To determine the antihypertensive efficacy and safety of the fixed-dose combination of the non-dihydropiridine calcium channel blocker (CCB) and ACE inhibitor verapamil SR/trandolapril 180/2 mg (V + T), versus trandolapril 2 mg (T), versus placebo (P) in previously untreated type 2 diabetic patients diagnosed as having HNBP or BISH.

METHODS

Multicentric, double-blind, placebo-controlled study with a 16-week follow-up in three groups totalling 438 participants. The primary end-point was to attain the recommended guideline goal of a systolic BP (SBP) value lower than 130 mmHg in all patients and a diastolic BP (DBP) value lower than 85 mmHg in HNBP. Participants were randomized (2:2:1) to verapamil V + T, T, or P. Doses were doubled at week 8 if BP was not controlled.

RESULTS

Both active groups were more effective than placebo to decrease SBP and DBP. The mean difference in SBP from placebo was 7.1 mmHg (3.3-10.9, 95% confidence interval (CI); P < 0.001) for T and 7.8 mmHg (3.9-11.6, 95% CI; P < 0.001) for V + T, with no statistical difference between both active groups. Combined treatment (V + T) decreased DBP by 4.6 mmHg (2.3-6.9, 95% CI; P < 0.001) more than placebo and 2.1 mmHg (0.3-4.0, 95% CI; P = 0.021) more than T. At the end of the study, 36.5% in the T group, 37.8% in the V + T group, and 14.9% (P = 0.009, P versus V + T and T) had attained the primary end-point. No significant difference was found between T and V + T with regard to the percentage of good control for SBP, but the control rate on the DBP (DBP < 85 mmHg) was significantly higher in the V + T group (88.8%), when compared with T (79.1%) or P (63.5%) (P = 0.002). Withdrawal rates due to adverse effects did not differ among trandolapril alone (9.4%), the combination (11.7%) and placebo (8.1%).

CONCLUSION

Antihypertensive treatment is more effective than placebo for controlling SBP and DBP in previously untreated participants with type 2 diabetes exhibiting low threshold BP values. Combination therapy with verapamil SR/trandolapril was more effective than trandolapril alone for controlling DBP.

Dual blockade of the renin-angiotensin system in diabetic nephropathy

The presence of inadequately controlled hypertension in a diabetic patient with clinical signs of renal involvement portends a poor prognosis. Initial assessment should include ruling out factors which may exacerbate the hypertension and careful assessment of the stage of hypertension, renal function and amount of proteinuria. Intensive treatment requires finding a combination of medications which will reduce not only blood pressure but also proteinuria. It is suggested that treatment should be started with an ACE inhibitor or an AT1 receptor blocker often in a fixed combination with a low-dose thiazide diuretic. Calcium channel blockers and beta-blockers may be added if required as second or third-line agents. In patients not responding to this combination, the dosages of the ACE inhibitor or AT1 blocker should be titrated upwards in order to obtain the maximal therapeutic effect. However, if this is still insufficient, dual blockade of the RAS should be considered and even an aldosterone receptor blocker may need to be added to the therapeutic regimen. It should be remembered that such a patient requires close monitoring in order to be sure that he is compliant with respect to the prescribed treatment and that there are no side-effects such as hyperkalaemia.

Is it time to measure microalbuminuria in hypertension?

Former guidelines on hypertension never made a commitment to the detection of microalbuminuria for screening or follow-up of hypertensive patients. On the other hand, growing evidence support the contributory role of microalbuminuria in the prediction of absolute cardiovascular risk in hypertension and document the potential relevance of this parameter to the initial choice of antihypertensive treatment. Upcoming new guidelines and diagnostic algorithms in hypertension need to underscore the clinical positioning of microalbuminuria for stratification of risk and follow-up purposes.