Coronary vasomotor abnormalities in insulin-resistant individuals

Ann Intern Med. 2004 May 4;140(9):700-8. doi: 10.7326/0003-4819-140-9-200405040-00009.


Background: Insulin resistance is a metabolic spectrum that progresses from hyperinsulinemia to the metabolic syndrome, impaired glucose tolerance, and finally type 2 diabetes mellitus. It is unclear when vascular abnormalities begin in this spectrum of metabolic effects.

Objective: To evaluate the association of insulin resistance with the presence and reversibility of coronary vasomotor abnormalities in young adults at low cardiovascular risk.

Design: Cross-sectional study followed by prospective, open-label treatment study.

Setting: University hospital.

Patients: 50 insulin-resistant and 22 insulin-sensitive, age-matched Mexican-American participants without glucose intolerance or traditional risk factors for or evidence of coronary artery disease.

Intervention: 3 months of thiazolidinedione therapy for 25 insulin-resistant patients.

Measurements: Glucose infusion rate in response to insulin infusion was used to define insulin resistance (glucose infusion rate < or = 4.00 mg/kg of body weight per minute [range, 0.90 to 3.96 mg/kg per minute]) and insulin sensitivity (glucose infusion rate > or = 7.50 mg/kg per minute [range, 7.52 to 13.92 mg/kg per minute]). Myocardial blood flow was measured by using positron emission tomography at rest, during cold pressor test (largely endothelium-dependent), and after dipyridamole administration (largely vascular smooth muscle-dependent).

Results: Myocardial blood flow responses to dipyridamole were similar in the insulin-sensitive and insulin-resistant groups. However, myocardial blood flow response to cold pressor test increased by 47.6% from resting values in insulin-sensitive patients and by 14.4% in insulin-resistant patients. During thiazolidinedione therapy in a subgroup of insulin-resistant patients, insulin sensitivity improved, fasting plasma insulin levels decreased, and myocardial blood flow responses to cold pressor test normalized.

Limitations: The study was not randomized, and it included only 1 ethnic group.

Conclusions: Insulin-resistant patients who do not have hypercholesterolemia or hypertension and do not smoke manifest coronary vasomotor abnormalities. Insulin-sensitizing thiazolidinedione therapy normalized these abnormalities. These results suggest an association between insulin resistance and abnormal coronary vasomotor function, a relationship that requires confirmation in larger studies.

Publication types

  • Clinical Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Body Mass Index
  • Coronary Circulation / drug effects
  • Coronary Circulation / physiology*
  • Cross-Sectional Studies
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / physiology
  • Female
  • Humans
  • Hypoglycemic Agents / therapeutic use
  • Insulin Resistance / physiology*
  • Male
  • Mexican Americans
  • Muscle, Smooth, Vascular / drug effects
  • Muscle, Smooth, Vascular / physiology
  • Prospective Studies
  • Thiazolidinediones / therapeutic use
  • Tomography, Emission-Computed
  • Vasomotor System / drug effects
  • Vasomotor System / physiology*


  • Hypoglycemic Agents
  • Thiazolidinediones
  • 2,4-thiazolidinedione