The influence of diabetes mellitus on plaque volume and vessel size in patients undergoing percutaneous coronary intervention

Cohort comparison study of cardiac disease and atherosclerotic burden in type 2 diabetic adults using whole body cardiovascular magnetic resonance imaging

BACKGROUND

Whole body cardiovascular MR (WB CVMR) combines whole body angiography and cardiac MR assessment. It is accepted that there is a high disease burden in patients with diabetes, however the quantification of the whole body atheroma burden in both arterial and cardiac disease has not been previously reported. In this study we compare the quantified atheroma burden in those individuals with and without diabetes by clinical cardiovascular disease (CVD) status.

METHODS

158 participants underwent WB CVMR, and were categorised into one of four groups: (1) type 2 diabetes mellitus (T2DM) with CVD; (2) T2DM without CVD; (3) CVD without T2DM; (4) healthy controls. The arterial tree was subdivided into 31 segments and each scored according to the degree of stenosis. From this a standardised atheroma score (SAS) was calculated. Cardiac MR and late gadolinium enhancement images of the left ventricle were obtained for assessment of mass, volume and myocardial scar assessment.

RESULTS

148 participants completed the study protocol--61% male, with mean age of 64 ± 8.2 years. SAS was highest in those with cardiovascular disease without diabetes [10.1 (0-39.5)], followed by those with T2DM and CVD [4 (0-41.1)], then those with T2DM only [3.23 (0-19.4)] with healthy controls having the lowest atheroma score [2.4 (0-19.4)]. Both groups with a prior history of CVD had a higher SAS and left ventricular mass than those without (p < 0.001 for both). However after accounting for known cardiovascular risk factors, only the SAS in the group with CVD without T2DM remained significantly elevated. 6% of the T2DM group had evidence of silent myocardial infarct, with this subcohort having a higher SAS than the remainder of the T2DM group [7.7 (4-19) vs. 2.8 (0-17), p = 0.024].

CONCLUSIONS

Global atheroma burden was significantly higher in those with known cardiovascular disease and without diabetes but not in those with diabetes and cardiovascular disease suggesting that cardiovascular events may occur at a lower atheroma burden in diabetes.

Comparison of the diagnostic performance of 64-slice computed tomography coronary angiography in diabetic and non-diabetic patients with suspected coronary artery disease

BACKGROUND

Diabetics have high prevalence of subclinical coronary artery disease (CAD) with typical characteristics (diffuse disease, large calcifications). Although 64-slice multidetector computed tomography (MDCT) coronary angiography has high diagnostic accuracy to detect CAD, its diagnostic performance in diabetics with suspected CAD is unknown. To compare the diagnostic performance of 64-slice MDCT between diabetics and non-diabetics with suspected CAD scheduled for invasive coronary angiography (ICA).

METHODS

We enrolled one hundred and five diabetic patients (92 men, age 65 +/- 9 years, Group 1) and 105 non-diabetic patients (63 men, age 63+/-5 years, Group 2) with indication to ICA for suspected CAD undergoing coronary 64-slice MDCT before ICA.

RESULTS

In Group 1, the overall feasibility of coronary artery visualization was 93.8%. The most frequent artifact was blooming due to large coronary calcifications (54 artifacts, 67%). In Group 2, the overall feasibility was significantly higher vs. Group 1 (97%, p < 0.0001). In Group 1, the segment-based analysis showed a MDCT sensibility, specificity, positive predictive value, negative predictive value and accuracy for the detection of ≥50% luminal narrowing of 77%, 90%, 70%, 93% and 87%, respectively. In Group 2, all these parameters were significantly higher vs. Group 1. In the patient-based analysis, specificity, negative predictive value and accuracy were significantly lower in Group 1 vs. Group 2.

CONCLUSIONS

Although MDCT has high sensitivity for early identification of significant CAD in diabetics, its diagnostic performance is significantly reduced in these patients as compared to non-diabetics with similar clinical characteristics.

Can surgeons do complete revascularization in diabetic patients using the off-pump technique?

BACKGROUND

: The arguments are discussed as to whether or not to proceed with multivessel percutaneous coronary intervention, with or without a drug-eluting stent, in patients with diabetes mellitus (DM), including (1) surgeons unable to complete revascularization because of smaller native arteries; and (2) diabetic patients being sicker and having higher operative mortality rates than nondiabetic patients (non-DM), particularly with the conventional coronary artery bypass surgery (on-pump) technique. To support or dispute the claims, a retrospective review of 480 consecutive patients at a single institution (195 DM and 285 non-DM) was carried out. Observations were made to see whether diabetes is a predictor of poor outcomes.

MATERIALS AND METHODS

: The preoperative comorbidity, intraoperative measurement of the size of the artery at the site of anastomosis with different gauged probes, and the number of grafts per patient were recorded. Intraoperative and postoperative variables between two groups were compared. The observed number of grafts (O) after surgery was compared with the number of grafts predicted (P) before surgery. The O/P ratio or "completion index" of ≥1 signifies complete revascularization. Logistic regression analysis was used to test the possibility that diabetes is a predictor of poor outcomes.

RESULTS

: Diabetic patients were older, with more comorbidity (congestive heart failure, peripheral vascular diseases, dialysis-dependent). The number of grafts per patient was 4.2 ± 1.3 (DM) and 4.2 ± 1.3 (non-DM). The size of 742 DM and 949 non-DM arteries were gauged. There was no statistical difference in size between DM and non-DM (in millimeters) at each artery. All ratios ranged from 0.9 to 1.2, indicating similarity between DM and non-DM. The only significant risk factor for operative death was low left ventricular ejection fraction (P = 0.001).

CONCLUSIONS

: Patients with DM were sicker but tolerated off-pump coronary artery bypass grafting as well as non-DM patients. The number of grafts per patient and O/P ratio signify the ability to perform complete revascularization. We are able to bypass the small target vessels, as anticipated. Diabetes is not a predictor of the outcomes.