Coronary artery disease (CAD) is the leading causes of morbidity and mortality in patients with diabetes mellitus. In these patients an elevated prevalence of silent myocardial ischemia has been reported. Thus, noninvasive assessment of cardiac risk may guide clinical decision-making in diabetic patients. This study assessed the role of SPECT imaging over clinical data for cardiac risk stratification in diabetic patients without known CAD.Materials and Methods: We enrolled 512 consecutive patients (265 men; mean age 63±8 years) with at least a five-year history of diabetes without known CAD or evidence of previous myocardial infarction on ECG. All patients underwent rest/stress Tc-99m sestamibi SPECT imaging with physical exercise (n=246) or dipyridamole (n=266) (0.142 mg/kg/min intravenous over 4 minutes). SPECT studies were interpreted by two independent observers utilizing a 17-segment model to determine summed stress, summed rest and summed difference scores. A computer program (CADENZA) was used to determine pre- and post-test likelihood of CAD. Beside diabetes, the program considered for analysis of pre-test likelihood of CAD the clinical variables based on Framingham risk factors. Taking into account SPECT imaging results, the program determined the patient’s post-test likelihood of CAD.Results: Based on the clinical variables, diabetic patients were divided into 3 groups: low (n=297), intermediate (n=145) and high (n=70) pre-test likelihood of CAD. An abnormal SPECT study was present in 44% of the patients. At analysis of variance, the total extent and severity of ischemic myocardium at SPECT was not significantly different among the 3 groups. After the addition of SPECT results, 299 patients were at low, 93 at intermediate and 120 at high likelihood of CAD. The likelihood of disease was significantly different when preand post-test likelihood of CAD were compared (Person chi-square, P<0.05). In particular, 22% of patients with low pre-test likelihood shifted in the intermediate (n=29) and high (n=37) posttest likelihood of CAD; 63% of patients with intermediate pre-test likelihood shifted in the low (n=67) and high (n=24) post-test likelihood of CAD; and 16% of patients with high pre-test likelihood shifted in the low (n=1) and intermediate (n=10) post-test likelihood of CAD. Conclusions: This study confirms that diabetic patients without known CAD may have myocardial ischemia at SPECT irrespective from the classical risk factors and suggests that SPECT imaging is useful in the definition of cardiac risk in these patients, particularly in those with intermediate pre-test likelihood of disease.

Role of SPECT imaging in the definition of cardiac risk in diabetic patients with no history of coronary artery disease: results of a prospective, multi-center trial

CITTANTI, Corrado;
2006

Abstract

Coronary artery disease (CAD) is the leading causes of morbidity and mortality in patients with diabetes mellitus. In these patients an elevated prevalence of silent myocardial ischemia has been reported. Thus, noninvasive assessment of cardiac risk may guide clinical decision-making in diabetic patients. This study assessed the role of SPECT imaging over clinical data for cardiac risk stratification in diabetic patients without known CAD.Materials and Methods: We enrolled 512 consecutive patients (265 men; mean age 63±8 years) with at least a five-year history of diabetes without known CAD or evidence of previous myocardial infarction on ECG. All patients underwent rest/stress Tc-99m sestamibi SPECT imaging with physical exercise (n=246) or dipyridamole (n=266) (0.142 mg/kg/min intravenous over 4 minutes). SPECT studies were interpreted by two independent observers utilizing a 17-segment model to determine summed stress, summed rest and summed difference scores. A computer program (CADENZA) was used to determine pre- and post-test likelihood of CAD. Beside diabetes, the program considered for analysis of pre-test likelihood of CAD the clinical variables based on Framingham risk factors. Taking into account SPECT imaging results, the program determined the patient’s post-test likelihood of CAD.Results: Based on the clinical variables, diabetic patients were divided into 3 groups: low (n=297), intermediate (n=145) and high (n=70) pre-test likelihood of CAD. An abnormal SPECT study was present in 44% of the patients. At analysis of variance, the total extent and severity of ischemic myocardium at SPECT was not significantly different among the 3 groups. After the addition of SPECT results, 299 patients were at low, 93 at intermediate and 120 at high likelihood of CAD. The likelihood of disease was significantly different when preand post-test likelihood of CAD were compared (Person chi-square, P<0.05). In particular, 22% of patients with low pre-test likelihood shifted in the intermediate (n=29) and high (n=37) posttest likelihood of CAD; 63% of patients with intermediate pre-test likelihood shifted in the low (n=67) and high (n=24) post-test likelihood of CAD; and 16% of patients with high pre-test likelihood shifted in the low (n=1) and intermediate (n=10) post-test likelihood of CAD. Conclusions: This study confirms that diabetic patients without known CAD may have myocardial ischemia at SPECT irrespective from the classical risk factors and suggests that SPECT imaging is useful in the definition of cardiac risk in these patients, particularly in those with intermediate pre-test likelihood of disease.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/518073
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