Abstract
OBJECTIVES:
To investigate the adverse effect of type 2 diabetes on coronary artery anatomy.
PATIENTS AND METHODS:
The coronary angiograms of 1564 consecutive patients were analyzed. The coronary lesions of patients with and without type 2 diabetes were compared.
RESULTS:
Seventy-four diabetic and 824 nondiabetic patients were found to have coronary artery disease. Diabetic patients had more multivessel (48.7% versus 34.7%, P<0.01), multilesion (64.9% versus 46.1%, P<0.05), extensive (51.4% versus 7.8%, P<0.01) and small vessel disease (95.2% versus 39.8%, P<0.01) than nondiabetic patients.
CONCLUSIONS:
Type 2 diabetes is a significant risk factor for coronary artery disease. These findings may provide useful information for the future development of therapeutic strategies.
Keywords: Coronary angiogram, Coronary artery disease, Diabetes mellitus
Diabetes mellitus is a major risk factor for the development of coronary artery disease and adversely affects patients’ overall clinical outcomes. The absolute risk of death due to coronary artery disease is three to five times higher in patients with diabetes than in those without diabetes, regardless of the cholesterol concentration (1). The two-year prognosis of diabetics who are hospitalized with unstable angina or non-Q wave infarction is significantly worse than that of nondiabetics (2). Patients with diabetes mellitus have a less favourable clinical outcome after successful percutaneous coronary intervention, manifested by a higher incidence of restenosis of the coronary artery or stent, a higher incidence of myocardial infarction or re-infarction, and a lower survival rate (3–6). After coronary artery bypass grafting, diabetic patients had twice the mortality of nondiabetic patients (7).
Diabetes is an emerging epidemic in developing countries, with an estimated increase of more than 170% in China (8). The purpose of the present study was to investigate the effect of type 2 diabetes on the extent and severity of coronary artery disease, by comparing the angiograms of diabetic and nondiabetic patients.
PATIENTS AND METHODS
Patients
Between January 1991 and June 2001, 1564 patients (1156 male) underwent coronary angiography for suspected coronary artery disease at Taishan Medical College. Type 2 diabetes had been diagnosed in 84 of these patients 0.5 to 30 years before the angiogram. Seventy-four (88.1%) of the diabetic and 824 (55.7%) of the nondiabetic patients were found to have coronary artery disease, and were subsequently analyzed in the present study.
Angiography
Coronary angiography was performed with the standard Judkins techniques. Coronary artery disease was defined as stenosis of a coronary artery of 50% or greater. Multivessel disease was defined as the involvement of any three or more of the following four arteries: the left main artery, the left descending artery, the left circumflex artery and the right coronary artery. Multilesion disease was defined as three or more lesions in a single vessel, whereas an extensive lesion was defined as a stenosis of more than 10 mm in length. Smaller-vessel disease was defined as a lesion with a diameter of less than 2.5 mm in the distant part of the left descending artery, the left circumflex artery, the right coronary artery or their septal branches, or in the obtuse marginal or posterior descending arteries.
Statistical analysis
Data were expressed as means ± SD. Differences between groups were analyzed by ANOVA.
RESULTS
There was no significant difference in the baseline data between diabetic and nondiabetic patients (Table 1). The incidence of multivessel, multilesion, extensive and smaller-vessel disease in diabetic patients was higher than that in nondiabetic patients (Table 1).
TABLE 1.
Characteristics of patients with coronary artery disease with diabetes mellitus (DM) and without DM (non-DM)
| DM (n=74) | Non-DM (n=824) | P | |
|---|---|---|---|
| Male, n (%) | 56 (75) | 610 (74.0) | NS |
| Age, years (mean ± SD) | 59.0±8.2 | 55.4±7.7 | NS |
| Multivessel disease, n (%) | 36 (48.7) | 286 (34.7) | <0.01 |
| Multilesion disease, n (%) | 48 (64.9) | 380 (46.1) | <0.05 |
| Extensive disease, n (%) | 38 (51.4) | 64 (7.8) | <0.01 |
| Smaller vessel disease, n (%) | 70 (94.6) | 328 (39.8) | <0.01 |
NS Not significant
More diabetic patients than nondiabetic patients had left main and left circumflex coronary artery disease (Figure 1). The most commonly involved coronary artery in diabetic patients was the left circumflex artery, followed by the left descending artery, and the right and left main coronary arteries (Figure 1). In nondiabetic patients, however, the most commonly diseased coronary artery was the left descending artery, followed by the left circumflex artery, and the right and left main arteries (Figure 1).
Figure 1).
The incidence of diseased coronary arteries in patients with diabetes mellitus (DM) and those without diabetes mellitus (non-DM). LAD Left anterior descending; LCX Left circumflex; LM Left main; RCA Right coronary artery
DISCUSSION
Our findings in this Chinese population are consistent with those of angiographic studies in other populations in which patients with diabetes mellitus experienced more three-vessel disease than nondiabetic patients (9–11). The more severe and extensive coronary artery lesions, and poorer collateral circulation in diabetic patients reported in another study (9) may have contributed to the less favourable clinical outcomes of this patient population.
The mechanism of the increased severity of coronary artery disease in type 2 diabetics than in nondiabetics in the study is unclear. Insulin resistance in patients with type 2 diabetes often leads to hyperinsulinemia, which in turn causes a variety of other abnormalities, including elevated triglyceride levels, low levels of high density lipoprotein cholesterol, enhanced secretion of very low density lipoprotein, disorders of coagulation, increased vascular resistance and hypertension (12). All of these consequences contribute to the development of atherosclerosis and coronary artery disease. Further studies are required to clarify the role of hyperinsulinemia in the development of coronary artery disease in patients with type 2 diabetes.
CONCLUSIONS
Type 2 diabetes has a significant adverse effect on the anatomy of coronary arteries, causing more multivessel and extensive coronary artery disease than in nondiabetic patients. These findings may provide useful information in the development of new therapeutic strategies for this special patient population.
REFERENCES
- 1.Stamler J, Vacarro O, Neaton JD. Diabetes, other risk factors, and 12-yr cardiovascular mortality for men screened in the Multiple Risk Factor Intervention Trial. Diabetes Care. 1993;16:434–44. doi: 10.2337/diacare.16.2.434. [DOI] [PubMed] [Google Scholar]
- 2.Malmberg K, Yusuf S, Gerstein HC, et al. for the OASIS Registry Investigators Impact of diabetes on long-term prognosis in patients with unstable angina and non-Q-wave myocardial infarction: Results of the OASIS (Organisation to Assess Strategies for Ischemic Syndromes) Registry. Circulation. 2000;102:1014–9. doi: 10.1161/01.cir.102.9.1014. [DOI] [PubMed] [Google Scholar]
- 3.Woodfield SL, Lundergan CF, Reiner JS, et al. Angiographic findings and outcome in diabetic patients treated with thrombolytic therapy for acute myocardial infarction – the GUSTO-I experience. J Am Coll Cardiol. 1996;28:1661–9. doi: 10.1016/s0735-1097(96)00397-x. [DOI] [PubMed] [Google Scholar]
- 4.Elezi S, Kastrati A, Pache J, et al. Diabetes mellitus and the clinical and angiographic outcome after coronary stent placement. J Am Coll Cardiol. 1998;32:1866–73. doi: 10.1016/s0735-1097(98)00467-7. [DOI] [PubMed] [Google Scholar]
- 5.Silva JA, Ramee SR, White CJ, et al. Primary stenting in acute myocardial infarction: Influence of diabetes mellitus in angiographic results and clinical outcome. Am Heart J. 1999;138:446–55. doi: 10.1016/s0002-8703(99)70146-8. [DOI] [PubMed] [Google Scholar]
- 6.Schofer J, Schluter M, Rau T, Hammer F, Haag N, Mathey DG. Influence of treatment modality on angiographic outcome after coronary stenting in diabetic patients: A controlled study. J Am Coll Cardiol. 2000;35:1554–9. doi: 10.1016/s0735-1097(00)00574-x. [DOI] [PubMed] [Google Scholar]
- 7.Herlitz J, Wognsen GB, Karlson BW, et al. Mortality, mode of death and risk indicators for death during 5 years after coronary artery bypass grafting among patients with and without a history of diabetes mellitus. Coron Artery Dis. 2000;11:339–46. doi: 10.1097/00019501-200006000-00007. [DOI] [PubMed] [Google Scholar]
- 8.King H, Aubert RE, Herman WH. Global burden of diabetes, 1995–2025: prevalence, numerical estimates, and projection. Diabetes Care. 1998;21:1414–31. doi: 10.2337/diacare.21.9.1414. [DOI] [PubMed] [Google Scholar]
- 9.Abaci A, Oguzhan A, Kahraman S, et al. Effect of diabetes mellitus on formation of coronary collateral vessels. Circulation. 1999;99:2239–42. doi: 10.1161/01.cir.99.17.2239. [DOI] [PubMed] [Google Scholar]
- 10.Melidonis A, Dimopoulos V, Lempidakis E, et al. Angiographic study of coronary artery disease in diabetic patients in comparison with nondiabetic patients. Angiology. 1999;50:997–1006. doi: 10.1177/000331979905001205. [DOI] [PubMed] [Google Scholar]
- 11.Natali A, Vichi S, Landi P, Severi S, L’Abbate A, Ferrannini E. Coronary atherosclerosis in type II diabetes: angiographic findings and clinical outcome. Diabetologia. 2000;43:632–41. doi: 10.1007/s001250051352. [DOI] [PubMed] [Google Scholar]
- 12.Saltiel AR. Series introduction: the molecular and physiological basis of insulin resistance: emerging implications for metabolic and cardiovascualr diseases. J Clin Invest. 2000;106:163–4. doi: 10.1172/JCI10533. [DOI] [PMC free article] [PubMed] [Google Scholar]