Therapies for type 2 diabetes and coronary artery disease

[Percutaneous coronary intervention versus bypass surgery in patients with diabetes and multivessel coronary disease. Coronary revascularization after FREEDOM]

Is coronary revascularization required in a patient with chronic stable coronary artery disease or can optimized medical therapy (OMT) alone be a sufficient alternative? This question has been controversially discussed for non-diabetics as well as for diabetics since the COURAGE and BARI 2D trials. According to our present knowledge, a patient will benefit from coronary revascularization only when either a non-invasive test method, such as single photon emission computed tomography (SPECT) or positron emission tomography (PET) myocardial scintigraphy, stress echocardiography or stress nuclear magnetic resonance imaging, can detect relevant, objective evidence of ischemia >10% of the left ventricular myocardium or when a pathological fractional flow reserve (FFR) <0.80 can be measured in an invasive procedure for an angiographically detectable coronary stenosis. If similar relevant ischemia can be non-invasively or invasively objectified in a patient with chronic stable multivessel coronary artery disease, the often controversially discussed question arises particularly in diabetics whether a percutaneous coronary intervention (PCI) with implantation of drug-eluting stents or coronary artery bypass surgery should be favored. The FREEDOM study (Future Revascularization Evaluation in Patients with Diabetes Mellitus: Optimal Management of Multivessel Disease), published in November 2012, was the first prospective randomized study to examine this issue in diabetic patients with multivessel coronary artery disease. Despite a higher rate of stroke in the surgical cohort, after an average follow-up time of 3.8 years a significant prognostic advantage in favor of bypass surgery was detected for a combined primary endpoint of all-cause mortality, nonfatal myocardial infarction and nonfatal stroke. Thus, in the new ESC guidelines on diabetes, pre-diabetes and cardiovascular diseases developed with the EASD of the European Society of Cardiology and published in 2013, coronary bypass surgery has a class I, level of evidence A recommendation for patients with diabetes mellitus, chronic stable multivessel coronary disease and a synergy between PCI with taxus and cardiac surgery (SYNTAX) score >22. The decision for or against a PCI/stent implantation or coronary bypass surgery in a diabetic patient with chronic stable multivessel coronary artery disease should therefore be made with the patient only after a detailed informed consent discussion and comprehensive explanation of both treatment options. In controversial cases, particularly with an equivocal SYNTAX score around 22, relevant comorbidities or anticipated method-specific complications, a one-stage ad hoc intervention during the diagnostic coronary angiography should be rejected in favor of a two-stage procedure with prior discussion of both treatment options in the heart team comprising noninvasive cardiologists, interventional cardiologists and cardiac surgeons.

Rosiglitazone and outcomes for patients with diabetes mellitus and coronary artery disease in the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial

BACKGROUND

Rosiglitazone improves glycemic control for patients with type 2 diabetes mellitus, but there remains controversy regarding an observed association with cardiovascular hazard. The cardiovascular effects of rosiglitazone for patients with coronary artery disease remain unknown.

METHODS AND RESULTS

To examine any association between rosiglitazone use and cardiovascular events among patients with diabetes mellitus and coronary artery disease, we analyzed events among 2368 patients with type 2 diabetes mellitus and coronary artery disease in the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial. Total mortality, composite death, myocardial infarction, and stroke, and the individual incidence of death, myocardial infarction, stroke, congestive heart failure, and fractures, were compared during 4.5 years of follow-up among patients treated with rosiglitazone versus patients not receiving a thiazolidinedione by use of Cox proportional hazards and Kaplan-Meier analyses that included propensity matching. After multivariable adjustment, among patients treated with rosiglitazone, mortality was similar (hazard ratio [HR], 0.83; 95% confidence interval [CI], 0.58-1.18), whereas there was a lower incidence of composite death, myocardial infarction, and stroke (HR, 0.72; 95% CI, 0.55-0.93) and stroke (HR, 0.36; 95% CI, 0.16-0.86) and a higher incidence of fractures (HR, 1.62; 95% CI, 1.05-2.51); the incidence of myocardial infarction (HR, 0.77; 95% CI, 0.54-1.10) and congestive heart failure (HR, 1.22; 95% CI, 0.84-1.82) did not differ significantly. Among propensity-matched patients, rates of major ischemic cardiovascular events and congestive heart failure were not significantly different.

CONCLUSIONS

Among patients with type 2 diabetes mellitus and coronary artery disease in the BARI 2D trial, neither on-treatment nor propensity-matched analysis supported an association of rosiglitazone treatment with an increase in major ischemic cardiovascular events.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00006305.

Adiponectin may improve osseointegration of dental implants in T2DM patients

Type 2 diabetes mellitus (T2DM) is the most common form of diabetes. Compared with the general population, a higher failure rate is seen in T2DM patients. There is also evidence that chronically high levels of plasma glycemia leads to inflammatory effect and a negative influence on bone formation and remodeling, and reduce osseointegration of implants. Recently studies reveal that adiponectin is an insulin-sensitizing adipokine, and closely associated with T2DM. Adiponectin has potent anti-inflammatory properties and has been shown to increase bone density by inhibiting osteoclast formation and promoting the formation of osteoblasts. We therefore hypothesize systemically infused or locally used adiponectin could accelerate osseointegration of dental implants in T2DM. Our hypothesis could help to create an option to improve success ratio of dental implants in T2DM by the replenishment of adiponectin in T2DM patients.

[Bypass surgery versus percutaneous coronary intervention in patients with diabetes mellitus]

At present, in patients with diabetes mellitus and coronary multivessel disease no fixed general recommendation can be given in favor or to the disadvantage of surgical revascularization or in favor or to the disadvantage of percutaneous coronary intervention (PCI). In cases with an evidence-based indication for coronary revascularization because of clinical symptoms and/or proven ischemia, both therapeutic alternatives of bypass surgery or PCI are electable. The decision, which method of revascularization to prefer, must be based on close analyses of individual risk profile, individual comorbidity, and individual coronary morphology. With correct indication, both therapeutic methods are equivalent regarding the prognostically important combined endpoint of death, nonfatal myocardial infarction, and stroke. For PCI, however, there is a higher probability of restenosis depending on the complexity of lesion morphology, requiring more often repeat interventions or revascularizations. Before deciding in subfavor of or against a surgical or nonsurgical revascularization procedure, the complexity of the coronary artery disease should be analyzed, for example using the SYNTAX Score. In patients with SYNTAX Scores > or = 33 and no contraindications to bypass surgery, a surgical revascularization should be preferred. In the intermediate group with SYNTAX Scores between 23 und 32, the advantages and disadvantages of bypass surgery or PCI, for instance, the increased probability of restenosis with a higher necessity of repeat revascularizations after PCI, should be extensively discussed with the patient. In patients with SYNTAX Scores between 0 and 22, the nonsurgical, interventional therapy using drug-eluting stents (DES) can be recommended as an equivalent alternative to bypass surgery. In meta-analyses of randomized controlled trials and meta-analyses of large registries with PCI in patients with diabetes mellitus, clear advantages of DES in comparison with bare-metal stents (BMS) could be shown. Especially for patients with diabetes mellitus, there is still no clear evidence in favor of or against a special DES type or in favor of or against a special stent covering. Further sufficiently powered randomized controlled trials with hard clinical endpoints comparing bypass surgery with PCI (e.g., FREEDOM trial) and comparing different types of DES in patients with diabetes mellitus and clear PCI indications must be awaited, before further recommendations can be given.