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Screening diabetic transplant candidates for coronary artery disease: identification of a low risk subgroup
1Department of Medicine, University of Minnesota School of Medicine, Minneapolis.
Insights
Diabetic kidney transplant candidates often have silent coronary artery disease (CAD). A new noninvasive screening algorithm accurately identifies low-risk patients, potentially avoiding unnecessary coronary angiography.
Area of Science:
- Nephrology
- Cardiology
- Transplantation
Background:
- Coronary artery disease (CAD) is a leading cause of mortality in diabetic patients undergoing renal transplantation.
- A significant proportion of diabetic transplant candidates have asymptomatic CAD, necessitating pre-transplant screening.
- Coronary angiography, while effective, carries risks including acute renal failure and high costs.
Purpose of the Study:
- To develop and validate a noninvasive screening algorithm for identifying diabetic renal transplant candidates at low risk for CAD.
- To reduce the need for invasive coronary angiography in select patient populations.
Main Methods:
- Coronary angiography was performed on 141 asymptomatic Caucasian type 1 diabetic renal transplant candidates.
- A screening algorithm was developed using clinical factors (age ≥45, smoking history, ST-T wave changes, diabetes duration ≥25 years) in patients under 45.
- The algorithm's accuracy was tested in independent cohorts.
Main Results:
- All patients aged 45 or older had CAD.
- In patients under 45, the algorithm identified CAD with 97% sensitivity and 96% negative predictive accuracy.
- Key risk factors identified: smoking (≥5 pack-years), EKG ST-T wave changes, and diabetes duration (≥25 years).
Conclusions:
- Coronary angiography is recommended for diabetic renal transplant candidates aged 45 and older.
- The developed noninvasive algorithm effectively identifies low-risk patients (<45 years) without significant risk factors, allowing angiography avoidance.
Abstract:
Coronary artery disease is the major cause of death in diabetic renal transplant recipients. Because one-third of diabetic transplant candidates have clinically silent coronary artery disease, many transplant centers recommend coronary angiography prior to transplantation. However, angiography is expensive and may precipitate acute renal failure. Therefore, we developed a noninvasive screening algorithm to identify patients at low risk for coronary artery disease (CAD), defined as one or more coronary stenoses > or = 50% diameter. We performed coronary angiography in 141 consecutive asymptomatic Caucasian type I diabetic renal transplant candidates. Fourteen of 16 patients age 45 or older had CAD. One hundred and twenty-five patients under age 45 were randomly divided into two groups. Ninety patients were used to identify clinical factors significantly associated with CAD which included smoking for five or more pack years, nonspecific ST-T wave changes on electrocardiogram, and diabetes duration 25 years or longer. The screening algorithm, "CAD is predicted in diabetic transplant candidates under age 45 with any of the above risk factors," was then tested in the remaining 35 patients and in 35 additional patients. In these 70 patients, the algorithm had a sensitivity of 97% and a negative predictive accuracy of 96%. We conclude that coronary angiography should be recommended to Caucasian type I diabetic renal transplant candidates age 45 or older because of the high probability of disease. In patients younger than 45 without a smoking history, ST-T wave changes on EKG, or diabetes longer than 25 years, the likelihood of CAD is low and angiography can be avoided.