[Impaired coronary flow reserve due to long-term smoking recovers after quitting]

Cigarette smoking is a major risk factor for coronary artery disease. The present study examined whether impaired coronary flow reserve by smoking can be recovered by quitting. Coronary flow velocity was measured by Doppler guide wire during coronary angiography and coronary flow reserve was determined by injecting 10 mg intracoronary papaverine in 45 patients who were present or former smokers. Twenty-three patients were smoking more than 800 cigarettes/day x years and 22 patients less than 800, and 13 patients had smoked more than 800 but had quit smoking at least for 5 years. None of the patients had any significant coronary stenosis in the left anterior descending artery where the Doppler probe was positioned, nor any coronary risk factors except smoking. Twenty-six non-smokers served as control subjects. There was no difference in the coronary flow reserve between controls and light smokers (3.3 +/- 0.7 vs 3.3 +/- 1.0), but it was significantly reduced in heavy smokers (2.6 +/- 0.8) compared to controls or light smokers (p < 0.05, p < 0.05, respectively), There was no significant difference in coronary flow reserve between controls, light smokers and ex-smokers (3.3 +/- 1.2). These results suggest that the deteriorating effect on the coronary flow reserve by smoking is corrected after its cessation.