Altered resistive vessel function after coronary angioplasty is not due to reduced production of nitric oxide.
BACKGROUND
The coronary vasodilator reserve with dipyridamole may be impaired immediately after successful angioplasty due to reduced endothelial production or release of nitric oxide. As the vasodilator response to exogenous nitrates is enhanced by endothelium removal or inhibition of nitric oxide synthesis, an increased vasodilator response to nitrovasodilators, such as nitroprusside, should occur.


METHODS
The coronary vasodilator reserve (maximal/basel coronary blood flow) with intravenous dipyridamole (0.56 mg/min for 4 min) was measured by Doppler catheterization before and after angioplasty in 10 patients with single-vessel coronary disease. At peak dipyridamole effect, incremental doses of nitroprusside (4-50 micrograms/min) were given intracoronary until systolic blood pressure fell by > or = 5 mmHg.


RESULTS
Before angioplasty, the coronary blood flow increased from 19.7 +/- 6.1 (mean +/- s.d.) at basal to 30.1 +/- 11.9 ml/min at the peak dipyridamole effect (P < 0.01), giving a coronary vasodilator reserve of 1.62 +/- 0.39 (range 1.20 - 1.96). After angioplasty, the coronary blood flow increased from 32.4 +/- 13.2 at basal to 53.4 +/- 23.3 ml/min at the peak dipyridamole effect (P < 0.01), giving a coronary vasodilator reserve of 1.77 +/- 0.64 (range 1.7-2.42). Sodium nitroprusside had no additional effect on coronary flow (49.5 +/- 20.4 and 52.2 +/- 18.0 ml/min) before and after a fall in systolic blood pressure, respectively.


CONCLUSIONS
The vasodilator response to dipyridamole was markedly impaired immediately after successful angioplasty, and was not augmented by intracoronary nitroprusside. Thus, a reduced production or release of nitric oxide in the coronary circulation does not seem to be responsible for the impaired vasodilator response after angioplasty.
Uren
N G
NG
Division of Cardiology, Hammersmith Hospital, London, UK. neal@leland.stanford.edu
Crake
T
T
Lefroy
D C
DC
Davies
G J
GJ
Maseri
A
A
D000328:Adult; D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D017023:Coronary Angiography; D003326:Coronary Circulation; D003327:Coronary Disease / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D004176:Dipyridamole / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D014655:Vascular Resistance / Q000187:drug effects*; D014665:Vasodilator Agents / Q000627:therapeutic use*
D014665:Vasodilator Agents; D009569:Nitric Oxide; D004176:Dipyridamole