Author + information
- Received October 25, 1994
- Revision received March 30, 1995
- Accepted April 7, 1995
- Published online September 1, 1995.
- Gianmario Sambuceti, MDa,
- Oberdan Parodi, MDa,*,
- Assuero Giorgetti, MDa,
- Piero Salvadori, ChDa,
- Mario Marzilli, MDa,
- Piero Dabizzi, MD*,
- Paolo Marzullo, MD, FESC, FACCa,
- Danilo Neglia, MDa and
- Antonio L'Abbate, MD, FESC, FACCa
- ↵*Address for correspondence: Dr. Oberdan Parodi, CNR Institute of Clinical Physiology, Via P. Savi, 8, 56100, Pisa, Italy.
Objectives The aim of this study was to evaluate myocardial blood flow regulation in collateral-dependent myocardium of patients with coronary artery disease.
Background Despite great clinical relevance, perfusion correlates of collateral circulation in humans have rarely been estimated by quantitative methods at rest and during stress.
Methods Nineteen patients with angina and isolated occlusion of the left anterior descending (n = 14) or left circumflex (n = 5) coronary artery were evaluated. Using positron emission tomography and nitrogen-13 ammonia, we obtained flow measurements at baseline, during atrial pacing-induced tachycardia and after intravenous administration of dipyridamole (0.56 mg/kg body weight over 4 min). Flow values in collateral-dependent and remote areas were compared with values in 13 normal subjects.
Results Flow at rest was similar in collateralized and remote myocardium (0.61 ± 0.11 vs. 0.63 ± 0.17 ml/min per g, mean ± 1 SD), and both values were lower than normal (1.00 ± 0.20 ml/min per g, p < 0.01). During pacing, blood flow increased to 0.83 ± 0.25 and 1.11 ± 0.39 ml/min per g in collateraldependent and remote areas, respectively (p < 0.05 vs. baseline); both values were lower than normal (1.86 ± 0.61 ml/min per g, p < 0.01). Dipyridamole induced a further increase in perfusion in remote areas (1.36 ± 0.57 ml/min per g, p < 0.01 vs. pacing) but not in collateral-dependent regions (0.93 ± 0.37 ml/min per g, p = NS vs. pacing); again, both values were lower (p < 0.01) than normal (3.46 ± 0.78 ml/min per g). Dipyridamole flow in collateral-dependent myocardium was slightly lower in patients with poorly developed than in those with well developed collateral channels (0.75 ± 0.29 vs. 1.06 ± 0.38 ml/min per g, respectively, p = 0.06); however, the former showed higher flow inhomogeneity (collateral/control flow ratio 0.58 ± 0.10 vs. 0.81 ± 0.22, respectively, p < 0.02). A linear direct correlation was observed between flow reserve of collateral-dependent and remote regions (r = 0.83, p < 0.01).
Conclusions Despite rest hypoperfusion, collateral-dependent myocardium maintains a vasodilator reserve that is almost fully utilized during increases in oxygen consumption. A global microvascular disorder might hamper adaptation to chronic coronary occlusion.
This study was presented in part at the 42nd Annual Scientific Session of the American College of Cardiology, Anaheim, California, March 1993. It was supported in part by the CNR-Targeted Project “Prevention and Control of Disease Factors,” Subproject “Control of Cardiovascular Disease,” from the National Research Council, Rome, Italy.
- Received October 25, 1994.
- Revision received March 30, 1995.
- Accepted April 7, 1995.
- American College of Cardiology