CORRELATION BETWEEN LOW DIASTOLIC BLOOD PRESSURE AND SEVERITY OF CORONARY ARTERY DISEASE USING SYNTAX SCORE

Abstract

Objective: Hypertension remains a leading cause of morbidity and mortality, and the optimum blood pressure target remains debated, especially in coronary artery disease, given concerns for reduced myocardial perfusion if diastolic blood pressure is too low. The aim of this work was to study the relationship between diastolic blood pressure (DBP) and severity, and burden of coronary artery disease (CAD) as quantified by SYNTAX Score. Design and method: Six hundred consecutive stable patients with signs or symptoms of CAD who underwent elective coronary angiography were included in the study. Patients were divided into three groups according to SYNTAX Score as low, intermediate, and high. Results: Patients were predominantly males (72%), their age ranged from 35 - 82 years, with mean age of 59.55 ± 9.44 years. 426 patients (71%) were hypertensive, 82.1%,69.4%,70% of high, intermediate, and low SYNTAX groups respectively had hypertension. SYNTAX score ranged from 2.0 – 53.0 with a mean of 17.32 ± 9.87. In DBP group <60 mmHg, SYNTAX score ranged from 8.0 – 53.0 with a mean of 26.47 ± 10.59. In DBP group 60 – 69 mmHg, SYNTAX score ranged from 5.0 – 45.50 with a mean of 22.13 ± 7.77. In DBP group 70 – 79 mmHg, SYNTAX score ranged from 3.0 - 34.0 with a mean of 13.91 ± 7.09. In DBP group > = 80 mmHg, SYNTAX score ranged from 2.0 – 46.50 with a mean of 12.90 ± 8.21, SYNTAX score was significant higher in DBP groups <60 and 60 – 69 mmHg than other groups (p < 0.001). High atherosclerotic burden was identified by the presence of intermediate or high SYNTAX score. The frequency of high atherosclerotic burden was significantly increased with decreasing DBP, for mean SYNTAX Scores of 41.1, 35.6, 10 and 13.3 in DBP <60, 60 – 69, 70 – 79, and > = 80 mmHg; p < 0.0001 for all. There was negative significant correlation between diastolic blood pressure and SYNTAX score (rs = -0.471, p < 0.001). Conclusions: A low DBP level had an independent association with high SYNTAX Score. Lower DBP, particularly <60 mmHg, may be important to recognize a potential pathophysiological contribution of too low DBP in the development of complexity and increased atherosclerotic burden, which is identified by the presence of intermediate or high SYNTAX Score in stable patients with obstructive CAD.