Author + information
- Received December 17, 1992
- Revision received April 15, 1993
- Accepted May 21, 1993
- Published online November 15, 1993.
- Wing-hung Leung, MD, MRCP∗
- ↵∗Address for correspondence: Dr. Wing-Hung Leung, Division of Cardiology, Department of Medicine, University of Hong Kong, Queen Mary Hospital, Pokfulam Road, Hong Kong, Hong Kong.
Objectives. This study evaluated the coronary vasomoter response after successful angioplasty of chronic total coronary occlusions and tested the hypothesis that that degree of distal vasoconstriction is dependent on the change in perfusion pressure.
Background. Although distal coronary vasoconstriction has been observed to occur frequently after successful percutaneous transluminal coronary angioplasty, little is known about this vasomotor response after angioplasty of chronic total occlusions.
Methods. Thirty patients with successful angioplasty of chronic total occlusions of the left coronary artery were studied. Quantitative coronary measurements were made at 0, 15 and 30 min after angioplasty and again after infracoronary nitroglycerin administration in coronary artery segments distal to the dilated lesion and in a control vessel. The change in distal perfusion pressure was defined as mean systemic arterial pressure minus residual mean transstenotic pressure gradient minus mean coronary wedge pressure.
Results. The distal segments showed greater vasoconstriction (vs. nitroglycerin) at 15 and 30 min compared with that at 0 min after angioplasty (32.3 ± 2.2% and 35,2 ± 2.5% vs. 12.5 ± 1.8%, respectively, p < 0.005) and compared with control segments (32.3 ± 2.2% vs. 12.1 ± 2.0%, p < 0.005, and 35,2 ± 2.5% vs. 12.5 ± 2.0%, p < 0.005, respectively). The degree of vasoconstriction at 30 min in the distal segments was found to correlate closely with the change in distal perfusion pressure (r = 0.73, p < 0.001).
Conclusions. Coronary distal vasoconstriction occurs frequently after successful angioplasty of chronic total occlusions and correlates closely with the change in coronary perfusion pressure. These findings support the hypothesis of reset epicardial coronary autoregulation in chronic bypoperfusion such that restoration of normal perfusion pressure after successful angioplasty may provoke reflex vasoconstriction.
☆ This study was supported in part by a grant (337/041/0041) from the Committee on Research and Conference Grants, University of Hong Kong. It was presented in part at the 66th Annual Scientific Sessions of the American Heart Association, November 1993, Atlanta, Georgia.
- Received December 17, 1992.
- Revision received April 15, 1993.
- Accepted May 21, 1993.