West: Dr. Frye approached the topic by raising and responding to his personal unanswered questions. He emphasized making decisions for the individual patient within the scope of study data and medical evidence. He felt greater conviction and commitment on the part of cardiologists to intervene aggressively in support of patients' diabetes could contribute significantly to improving patient outcomes after acute coronary events. He also noted that several ongoing trials might provide crucial additional information on management issues such as glycemic control through insulin or through insulin sensitization.

East: Dr. Lee said that the prevalence of diabetes is increasing explosively in Korea, as is mortality from coronary artery disease. Current interventional cardiology practice in Korea is guided by percutaneous coronary intervention study data from the pre-stent and stent eras. The aim of the Korean Multicenter Revascularization Registry was to collect data from recent, elective cases of 2- or 3-vessel disease and analyze for outcomes at 30 days and 1, 2, and 3 years.

A total of 3,279 patients were enrolled at 9 centers between January 1995 and December 2000. Baseline characteristics were similar for patients treated with intervention and those treated with bypass graft. Among the intervention patients, 68% received a stent. Almost all of the bypass patients (92%) received arterial grafts. Patients with diabetes represented similar proportions of both treatment cohorts (31% of intervention patients, 35% of bypass patients).

Data analysis shows that 30-day and 3-year mortality rates are similar for both procedures. Short-term morbidity and mortality is somewhat higher for the bypass group, primarily due to cerebrovascular events. However, the 3-year event-free survival rate is better for bypass patients than for those treated with intervention. This appears to be due to a greater revascularization rate with bypass procedures.

When the data are analyzed by patient type (diabetic or non-diabetic), 3-year mortality is higher for diabetic patients treated with intervention than for non-diabetic patients. There was no difference between diabetic and non-diabetic patients for bypass. Revascularization rates are higher among diabetic patients regardless of treatment procedure.

Within the intervention group, non-diabetic patients who received stents had better outcomes than those who did not receive stents, but there was no difference among diabetic patients. There was no such distinction in the bypass group between diabetic and non-diabetic patients.

Overall, Dr. Lee stated that bypass procedures are superior for revascularization rate, and this is particularly true among diabetic patients. Patients treated with intervention had a greater need for repeat revascularization procedures, and this was especially true for diabetic patients.

He concluded there isn't a large difference between intervention and bypass in terms of survival, either for the total patient population or for diabetic patients. He stated that future analyses may find that newer, stent procedures may make intervention sufficiently more successful that intervention proves equivalent to or superior to bypass as a revascularization procedure.

West: Dr. Frye opened by posing the questions he formed in response to the symposium title. First, why do we continue to have a "versus" mentality, as if intervention and bypass are in some sort of contest? Second, how can we reverse the adverse outcomes associated with diabetes? Are potential opportunities available in modification of management of acute myocardial infarction in diabetic patients or in use of arterial grafts? Is there an opportunity in greater exploration in how glycemic control is achieved (through insulin or increased insulin sensitivity)? Third, when should cardiologists intervene, particularly for patients who are diabetic and have no symptoms or only mild cardiovascular symptoms?

In the matter of procedure comparison, Dr. Frye cited findings from several studies that show diabetic patients who receive non-stented intervention have poorer outcomes than those who receive bypass with arterial grafts. Even a recent trial involving stented intervention showed that patients who received bypass had better outcomes. Thus, he concludes that bypass with arterial grafts is the superior procedure for diabetic patients with severe disease.

He believes that more focus on reversal of adverse outcome should be placed on medical management of patients' diabetes rather than choice of revascularization procedure. Specifically, he pointed out that a greater degree of risk factor control may benefit diabetic patients; he noted that a blood pressure maintained at less than 130/80 may improve prognosis. He mentioned that opportunities might also be present in more aggressive approaches to factors such as weight control, glycemic control, and use of medications such as ACE-inhibitors. He pointed to results from the UKPDS study to support his position, especially the finding that aggressive blood pressure control significantly decreased the incidence of both stroke and heart failure.

Another area he believes should receive more attention is medical care of diabetes itself for patients who have an acute myocardial infarction or those undergoing elective revascularization procedures.

One study found that diabetic patients with acute myocardial infarction who had 24 hours of insulin infusion followed by subcutaneous insulin had significantly lower mortality at one year than similar patients who received standard medical therapy.

Rates of Q-wave infarction are roughly the same among diabetic patients regardless of type of initial revascularization procedure (intervention or bypass). However, the mortality rates are strikingly different: 80% if no additional revascularization is done compared with 17% if arterial grafts are placed.

He asked whether we should consider aggressive insulin therapy after elective revascularization procedures as a means to improve outcome. He also noted that an observational study of in-hospital mortality after acute myocardial infarction showed that mortality was higher for diabetic patients given sulfonylurea drugs rather than insulin. From this he posed the question whether it makes a difference if glycemic control is achieved through insulin administration or increased insulin sensitivity.

Dr. Frye's last topic was the increase in cardiovascular mortality among patients with type 2 diabetes simultaneous with an overall decrease in such mortality. He asked whether early revascularization might decrease mortality among diabetic patients?

A current trial (Berry2) is posing exactly such questions: Is there a difference in 5-year mortality after acute myocardial infarction if immediate revascularization and aggressive medical management is given rather than simply medical management? Secondly, does it make a difference whether glycemic control is achieved through insulin or insulin sensitization?

Dr. Frye concluded by saying that cardiologists could make a difference to their individual patients during the wait for study results by applying the knowledge we have as aggressively as possible in support of their diabetic patients.