Background: Coronary vasoconstriction which occurs after percutaneous transluminal coronary angioplasty (PTCA) is abolished by i.e. phentolamine. In addition, an impairment of coronary vasodilator reserve (CVR) has been observed up to seven days after successful PTCA. To ascertain whether pre-treatment with the α1-adrenoceptor blocker doxazosin could prevent the blunting of CVR after the procedure, we carried out a randomized, double blind, controlled study on 26 patients (pts) with significant (>75%) single vessel disease undergoing elective PTCA. Methods: Twelve pts (G1) received doxazosin od on top of their standard treatment at the following doses: 1 mg for 3 days; 2 mg for 7 days and 4 mg for 7 days before PTCA. Treatment (4 mg) was continued for a week after the procedure. Fourteen pts (G2) received matching placebo. Myocardial blood flow (MBF) at baseline and following iv dipyridamole (dip, 0.56 mg/kg over 4 mins) was measured within 5 days of PTCA using positron emission tomography with oxygen-15 labeled water. CVR was calculated as dip/baseline MBF. Results: Baseline heart rate was 59±3 and 61±2 bpm and mean arterial pressure 88±3 and 91±2 mmHg in G1 and G2 respectively. Following dip heart rate was 79±4 and 76±3 bpm and mean arterial pressure 85±3 and 90 ±3 mmHg in G1 and G2 respectively. Baseline MBF was 0.92±0.06 ml/min/g in G1 and 1.05±0.08 ml/min/g in G2 (p=ns). Dip MBF was higher in G1 than G2 (2.46±0.28 vs 1.99±0.17 ml/min/g) although this difference fell short of statistical significance (p=0.15). CVR was significantly higher in pts treated with doxazosin (2.78±0.35 vs 1.95±0.18; p=0.03). Conclusion: Treatment with doxazosin prevented the impairment of CVR observed after PTCA. The reduction of CVR, observed despite successful revascularization, is consistent with adrenergically-mediated constriction of coronary resistive vessels.
|Issue number||SUPPL. 1|
|Publication status||Published - May 1999|
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine