Pharmacological treatment of diabetic patients with cardiovascular complications

Optimal treatment for coronary artery disease in patients with diabetes: percutaneous coronary intervention, coronary artery bypass graft, and medications

There are three strategies for patients with coronary artery disease (CAD): medical therapy, coronary artery bypass graft (CABG), and percutaneous coronary intervention (PCI). With the development of drug-eluting stents, PCI is now widely used as the firstline treatment around the world. The advantage of CABG over PCI, however, remains in patients with left main coronary artery disease, three-vessel disease, and diffuse CAD. PCI and CABG do not exist in isolation because relieving the symptoms of angina is not the goal of treatment of CAD. Secondary prevention with vigorous modification of risk factors should be initiated and maintained. Among coronary risk factors, diabetes mellitus (DM) remains the most important one to predict poor early and late outcomes even in patients undergoing complete revascularization with CABG. Lowering the blood glucose level is important, but strict glycemic control is not necessarily associated with further reduction of cardiovascular events. Modification of insulin resistance with pioglitazone and metformin, lipid-lowering therapy with a statin, lowering blood pressure to <130/80 mmHg, and antiplatelet therapy should be considered in individuals with DM. A major concern is suboptimal modifications of risk factors in patients with DM and CABG in the real world. We should bear in mind this treatment gap and provide medical therapy for patients who need it most.

Genetic factors play an important role in the pathogenesis of hyperlipidemia post-transplantation

BACKGROUND

Our purpose was to identify factors associated with hyperlipidemia post-transplantation in a Hispanic population.

METHODS

From 1985 to 1999, a kidney graft survival longer than 3 months occurred in 293 cases at the Instituto Nacional de la Nutrición. Most of the patients living in Mexico City were included (n = 83). The evaluation included a questionnaire, blood samples, and assessment of body composition and dietary habits. As many as possible first-degree relatives were studied.

RESULTS

Women had higher values of cholesterol (236 +/- 51 versus 215 +/-41; P < 0.05), low-density lipoprotein cholesterol (147 +/- 42 versus 131 +/- 34; P = 0.05), high-density lipoprotein cholesterol (57.3 +/- 14 versus 47.9 +/- 14; P = 0.002) and high-density lipoprotein-2 cholesterol. Isolated hypercholesterolemia was the most common lipid abnormality (40.9%), followed by mixed hyperlipidemia. Lipoprotein (a) greater than 30 mg/dL was found in 13 cases. Familial combined hyperlipidemia (FCHL) in the patient's relatives was a marker for dyslipidemia (odds ratio, 7.04; 95% confidence interval, 1.2 to 59.7). These cases had a worse lipid profile. Cyclosporine-treated FCHL patients had higher lipid levels compared with the non-FCHL, cyclosporine-treated patients. The effects of cyclosporine on the lipid levels were lower, but significant, after the exclusion of the FCHL cases.

CONCLUSION

Post-transplant dyslipidemia is determined by genetic and environmental factors. FCHL in the patient's relatives was associated with post-transplant hyperlipidemia; an additive effect with cyclosporine was found. The evaluation of the lipid profile of relatives may be useful for the assessment of the risk of post-transplant dyslipidemia.

Management of ischaemic heart disease in diabetic patients--is there a role for cardiac metabolic agents?

Diabetes mellitus (DM) increases the risk of cardiovascular events in patients with cardiovascular disease as well as in patients without any previous history of ischaemic heart disease (IHD). The management of IHD in diabetic patients remains a difficult challenge. However, some of these treatments are not as effective or well-tolerated in diabetic patients as in non-diabetic patients. An important effect of diabetes, that in turn influences cardiac function, is the switch from carbohydrate oxidation to free fatty acid and ketone oxidation. The correction of the alterations to cardiac metabolism associated with DM may represent a new approach to the management of IHD in these patients. Results obtained in anginal patients with the metabolic agent trimetazidine and in infarcted patients with glucose-insulin-potassium (GIK) are consistent with this hypothesis.

Management of coronary artery disease: therapeutic options in patients with diabetes

OBJECTIVES

The aim of this review is to discuss the particularities of coronary artery disease (CAD), the effect of intensive medical management and the outcome of percutaneous and surgical revascularization in patients with diabetes mellitus (DM).

BACKGROUND

CAD represents the leading cause of death in patients with DM. Numerous clinical, biological and angiographic risk factors have been shown to be associated with CAD in diabetic patients.

METHODS

Metabolic abnormalities in patients with DM including insulin resistance, hyperglycemia and dyslipidemia are briefly discussed. Then the potential roles of medical management and of percutaneous and surgical coronary revascularization are more extensively reviewed.

RESULTS

More vigorous control of hyperglycemia, hyperlipidemia, hypertension and other risk factors may be of crucial importance for risk reduction. Despite remarkable progress in recent years, the choice of a coronary revascularization strategy remains a challenge in these patients. Diabetic patients with CAD are predisposed to higher cardiovascular events after balloon angioplasty. Whether stenting and new antiplatelet drugs improve the results of percutaneous revascularization in this population needs further evaluation. The superiority of the surgical approach is also not definitely established. Therefore, many aspects of coronary revascularization are still unclear in these patients.

CONCLUSIONS

The results of ongoing randomized trials comparing multiple coronary stents to bypass surgery will likely provide some answers to our questions and additional randomized trials evaluating intensive diabetic control with or without coronary revascularization are needed to determine the best therapeutic approach in these patients.

Are angiotensin-converting enzyme inhibitors the best treatment for hypertension in type 2 diabetes?

The influence of hypertension on the clinical course and complications of type 2 diabetes is well established. With a special focus on angiotensin-converting enzyme inhibitors, this paper will review recently published results of prospective studies addressing two important aspects: the degree of blood pressure control, and the choice of antihypertensive regimen, in the prevention of complications in hypertensive type 2 diabetic patients. None of the recent studies have shown worse outcomes in patients treated with angiotensin-converting enzyme inhibitor-based regimens compared with alternative treatments. Some studies have suggested that angiotensin-converting enzyme inhibitor-based antihypertensive regimens may be superior to alternative treatments in reducing the risk of micro- and macrovascular complications, whereas other studies found similar effects for beta-blockers or calcium antagonists. Several trials showed beneficial effects of angiotensin-converting enzyme inhibitors over calcium antagonists, and have raised concerns about the use of dihydropyridine calcium antagonists in these patients. However, it remains to be determined whether there should be more reserved use of calcium antagonists in such patients, in the light of more major trials showing the safety and efficacy of calcium antagonists in preventing cardiovascular and renal endpoints. The degree of reduction of blood pressure rather than the choice of a particular drug may be the most important factor. Studies focusing on renal endpoints suggest that angiotensin-converting enzyme inhibitors have a better antiproteinuric effect than other agents, but this phenomenon is not always reflected by a more beneficial effect of angiotensin-converting enzyme inhibitors on the decline in glomerular filtration rate. In many ways, the question of whether angiotensin-converting enzyme inhibitors are the best class of agent in these patients is academic. Angiotensin-converting enzyme inhibitors are sufficiently safe, and, according to recent evidence, equally or more effective than other classes of agents. Tight blood pressure control is usually achievable only with a combination of agents. On the basis of available evidence, it appears that angiotensin-converting enzyme inhibitors, together with a low-dose cardioselective beta-blocker and a diuretic, should be used in most hypertensive type 2 diabetes patients, with calcium antagonists serving as reserve drugs in case of insufficient blood pressure control.

Non-linear effects of blood pressure and glycosylated haemoglobin on progression of diabetic nephropathy

OBJECTIVE

To describe the long-term simultaneous impacts of blood pressure and glycosylated haemoglobin values on the risk of progression of diabetic nephropathy.

DESIGN

Prospective, multicentre, 6-year follow-up study.

SETTING

One reference centre (university department of internal medicine) and nine general hospitals.

SUBJECTS

A total of 601 type 1 diabetic patients on intensive insulin therapy with and without diabetic nephropathy.

MAIN OUTCOME MEASURES

Progression of nephropathy was defined as change for the worse within five stages of nephropathy by at least one of these stages during the study period. By the use of logistic regression, the relationship between metabolic and blood pressure control and the risk of nephropathy progression was quantified.

RESULTS

The main determinants of nephropathy progression were glycosylated haemoglobin and blood pressure, which were both non-linearly associated with the risk of progression. No significant threshold levels for any of the predictors of progression were identified.

CONCLUSIONS

The results of this study underline the importance of optimizing metabolic and blood pressure control to arrest the progression of diabetic nephropathy without the evidence for a clinically relevant threshold effect.

Effects of intensified antihypertensive treatment in diabetic nephropathy: mortality and morbidity results of a prospective controlled 10-year study

OBJECTIVE

The aim of this study was to describe the effect of intensified antihypertensive therapy based on a structured teaching and treatment programme on the prognosis of hypertensive type 1 (insulin-dependent) diabetic patients with kidney disease.

DESIGN

The study was a controlled, prospective, parallel, 10-year follow-up trial.

PATIENTS AND INTERVENTIONS

A sequential sample of 91 hypertensive type 1 diabetic patients with overt diabetic nephropathy was prospectively followed for 10 years. Forty-five patients (intensified antihypertensive therapy; IT group) participated in an intensified antihypertensive therapy programme and 46 patients received routine antihypertensive treatment as provided by family physicians, consultants and local hospitals (routine antihypertensive therapy; RT group).

OUTCOME MEASURES

The main endpoint was death; secondary endpoints were renal replacement therapy, blindness and amputation.

RESULTS

Blood pressure was reduced in the IT group and increased in the RT group. During the follow-up period, 29 patients died, seven in the IT group and 22 in the RT group. The survival curves were significantly different (P = 0.0008). The main causes of death were cardiac. In a multiple Cox proportional hazards model, allocation to the IT group reduced the mortality risk [relative risk (RR) = 0.213; 95% confidence interval 0.089-0.509, P = 0.00051, while age (P = 0.0039) and mean blood pressure (P= 0.0113) increased this risk. In multiple Cox or multiple logistic regression models, the risks of dialysis (RR = 0.269, 95% confidence interval 0.110-0.656, P = 0.0039), blindness (odds ratio = 0.158, 95% confidence interval 0.037-0.684, P= 0.0136), and amputation (RR = 0.181, 95% confidence interval 0.047-0.703, P= 0.0135) were significantly lower in the IT group compared with the RT group (log rank P = 0.0008).

CONCLUSION

We conclude that intensified antihypertensive treatment, based on a hypertension teaching and treatment programme, reduces long-term morbidity and mortality in patients with diabetic nephropathy.

Imidapril, an angiotensin-converting enzyme inhibitor, improves insulin sensitivity by enhancing signal transduction via insulin receptor substrate proteins and improving vascular resistance in the Zucker fatty rat

Angiotensin-converting enzyme (ACE) inhibitors are antihypertensive agents, that inhibit the conversion of angiotensin I to angiotensin II, resulting in smooth-muscle relaxation and a reduction of vascular resistance. Recently, it has been suggested that ACE inhibitors improve insulin resistance in diabetic patients. To investigate the effect of an ACE inhibitor on insulin sensitivity, insulin signaling, and circulation, imidapril was administered orally or intraduodenally to Zucker fatty rats. Oral administration of imidapril improved insulin sensitivity based on the results of an oral glucose tolerance test (OGTT) and a decrease in urinary glucose secretion. Phosphatidylinositol 3-kinase (PI 3-kinase) activity associated with hepatic insulin receptor substrate-1 (IRS-1) in the insulin-stimulated condition was significantly enhanced 110% without a significant alteration in tyrosine phosphorylation of IRS-1 in the imidapril-treated group. In muscle, IRS-1 tyrosine phosphorylation and PI 3-kinase activity associated with IRS-1 in the insulin-stimulated condition were enhanced 70% and 20%, respectively, in the imidapril-treated group. In contrast, an alteration of the IRS-2 pathway was observed only in liver; a significant insulin-induced increase in the IRS-2-associated PI 3-kinase over the basal level was observed in the imidapril-treated group but not in the control. In addition, treatment with imidapril was shown to significantly reduce blood pressure and increase blood flow in the liver and muscle. These results suggest that the ACE inhibitor imidapril may improve insulin sensitivity not only by acting directly on the insulin signaling pathway but also by increasing blood flow in tissues via normalization of vascular resistance, a major cause of hypertension.