Review
Diabetic Retinopathy and Coronary Artery Disease From the Cardiac Surgeon’s Perspective

https://doi.org/10.1016/j.athoracsur.2007.07.066Get rights and content

Coronary artery disease is the leading cause of death in diabetics; therefore, the main purpose of managing coronary artery disease in diabetics should be to lengthen life expectancy. Recent evidence demonstrates that the severity of diabetic retinopathy is associated with a graded, increased risk of death from coronary artery disease and myocardial infarction. Recently, we found that the survival benefit of coronary artery bypass grafting over percutaneous coronary intervention is more apparent in patients with diabetic retinopathy than in diabetic patients without it. In this article, we review published studies evaluating the association between diabetic retinopathy and coronary artery disease, and we propose that coronary artery bypass surgery should be the first choice for revascularization of patients with diabetic retinopathy, especially in its early stage. Furthermore, coronary artery disease complicating diabetic retinopathy is often underdiagnosed, and all diabetic retinopathy patients should undergo screening for coronary artery disease followed by coronary artery bypass grafting. Future studies will probably comprise carefully performed cost-effective analyses of treatment effectiveness and prospective randomized studies comparing survival after coronary artery bypass grafting with that of survival after percutaneous coronary intervention, stratified by the stage of retinopathy.

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Literature Search

We included all cohort, case-controlled, cross-sectional, and experimental studies that evaluated the association between diabetic retinopathy and CAD, and we researched the MEDLINE database for reports published from January 1, 1966 to July 31, 2007 by using the following medical subject headings: “diabetic retinopathy and retinopathy,” in combination with each of the following terms: “survival, mortality, heart disease, coronary artery disease, myocardial infarction, angina, myocardial

Diabetic Retinopathy

Many studies evaluate the association between nephropathy and CAD [7, 8, 9]. In diabetic patients, however, nephropathy is a late sign of microvascular complication of diabetes mellitus, and the risk of nephropathy is genetically determined [10]. Microalbuminuria affects 20% to 40% of patients 10 to 15 years after the onset of diabetes. Progression to microalbuminuria, or overt nephropathy, occurs in 20% to 40% of patients during a period of 15 to 20 years after the onset of diabetes [11]. In

Increased Risk of Coronary Events in Patients with Diabetic Retinopathy

Ophthalmologists know well that patients with advanced diabetic retinopathy have a poor life expectancy. In a retrospective review of 128 diabetics followed-up at the Radcliffe Infirmary, Oxford, England, the 5-year mortality was 45% for those with PDR, 8% for those with only microaneurysms, and 8% for those without any retinopathy [17]. In a prospective study of 709 patients with type 2 diabetes taking insulin and followed-up for up to 13 years, Davis and colleagues [18] reported a 5-year

Increased Risk of Congestive Heart Failure in Patients with Diabetic Retinopathy

“Diabetic cardiomyopathy” is a clinical condition, diagnosed when cardiac dysfunction develops in diabetic patients in the absence of coronary heart disease and hypertension. Five experimental studies assessed the association between diabetic retinopathy and cardiac function in patients with type 1 [29, 30] or type 2 diabetes [31, 32, 33]. Cardiac function was evaluated in different methods, including echocardiography [30, 31, 32, 33] and radionuclide angiography [29]. In type 1 diabetes with

Underdiagnosis of CAD in Patients With Diabetic Retinopathy

Definitive data on the incidence and prevalence of CAD among patients with diabetic retinopathy are difficult to obtain. A study using questionnaires revealed that 15% of patients with sight-threatening diabetic retinopathy had reported themselves as having angina-like symptoms and 9% had a self-reported history of myocardial infarction [37]. However, these figures probably greatly underestimate the true burden of CAD in patients with diabetic retinopathy, because the disease is often

Survival Benefit of CABG Over PCI in Patients with Diabetic Retinopathy

Coronary revascularization (either with CABG or PCI) is the mainstay of treatment for CAD. Data from the Bypass Angioplasty Revascularization Investigation (BARI) study showed 15 excess deaths at 5-year follow-up for every 100 diabetic patients revascularized by PCI as opposed to CABG, and 20 excess deaths at 7 years and 22 excess deaths at 10 years, respectively [48, 49, 50]. In addition, strong evidence from several meta-analyses indicates that PCI, even with drug-eluting stents, does not

Coronary Implantation of Sirolimus-Eluting Stents in Patients with Diabetic Retinopathy

Currently, the number of patients with diabetes who undergo PCI with drug-eluting stents is increasing. Furthermore, Nargaz and colleagues [43] demonstrated that the diffuse nature of CAD is associated with the severity of diabetic retinopathy. Therefore, CAD with nonproliferative retinopathy is more amenable to PCI than to proliferative retinopathy. Recently, however, we demonstrated that patients with NPDR have a greater risk of target-vessel failure (ie, defined as a composite of death from

Long-Term Prognosis After CABG

We consider that patients with diabetic retinopathy and CAD should undergo CABG during the early stage of retinopathy, because the outcome of CABG in patients with advanced retinopathy is not satisfactory [14]. In our retrospective study of the 223 diabetic patients undergoing CABG, 12-year survival was 82% for diabetic patients without retinopathy, 56% for patients with mild-to-moderate NPDR, 36% for patients with severe NPDR, and 12% for those with PDR. One reason for the poor prognosis was

Diabetic Retinopathy as a Guide for Developing an Appropriate Coronary Revascularization Strategy

Our review demonstrated that the severity of diabetic retinopathy is closely related to the risk of future CAD events. Therefore, the treatment effect of coronary revascularization might vary according to severity of retinopathy, and the coronary revascularization strategy according to the severity of retinopathy is warranted. For diabetic patients during the stage that is free of retinopathy, PCI might be a preferable treatment method because these patients are a group in which the risk of

Future Directions

The main purpose of managing CAD in a diabetic population should be to lengthen life expectancy. Therefore, in patients with diabetic retinopathy who are at high risk of developing CAD death and myocardial infarction, CABG is strongly indicated. In Japan, 3 million people have been reported with diabetic retinopathy. If, at the very least of these 3 million patients, 20% have CAD and 80% have left anterior descending coronary artery disease, it can be expected that CABG will be strongly

Comment

In summary, coronary artery disease is the leading cause of death in diabetic patients. Evidence indicates that diabetic retinopathy is associated with an increased risk of death from coronary artery disease and myocardial infarction. Cardiac surgeons should have a commitment to improving the life expectancy of diabetic patients by performing CABG when there is a high risk of myocardial infarction and CAD death. Patients with diabetic retinopathy could benefit greatly from CABG. However, those

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