Correlation of twenty-four hours ambulatory blood pressure pattern with severity of stable coronary artery disease in hypertensive patients- A single centre cross sectional observational study

Abstract

Background & objectives:
Hypertension is one of the most widely prevalent diseases throughout the world, which is emerging as one of the leading causes of premature morbidity and mortality globally. Nocturnal blood pressure readings measured by ABPM also provide prognostic data. 24 hr Ambulatory BP and specifically nocturnal blood pressure has been found to be associated with superior predictive and prognostic value for target organ dysfunction and CVD events either symptomatic or asymptomatic. Purpose of our study is to find out the prevalence of dipper, non-dipper, reverse dipper and extreme dipper in patients with stable CAD and their association with severity of CAD.
Methods:
This study was conducted in NH- Rabindranath Tagore Institute, Kolkata. Study lasted for 18 months. This study is a single centre cross sectional observational study. All patients who met inclusion criteria were included in this study after a thorough informed consent. Once the patient was recruited, he was admitted for an elective angiogram. Routine clinical history, baseline demographics like age, sex, height, weight, Body Mass Index (BMI), and comorbidities like diabetes hypertension and history of smoking were recorded. During the admission the patient underwent a 24-hr ambulatory BP monitoring after significant coronary artery disease was diagnosed on an elective diagnostic coronary angiogram. All data was anonymized and entered into Microsoft excel spread sheets and computed with SPSS version 20 for measures of statistical significance. Patients were classified into non-dipper& (with a nocturnal drop of mean BP less than 10%), dipper (nocturnal drop of mean BP 10%), extreme dipper (nocturnal drop of mean BP ), or reverse dipper (nocturnal elevation of mean BP). Coronary artery disease was classified angiographically into single vessel and multi-vessel coronary artery disease.

Results:
In this present study population, mean age was 57.7±10.55 years, 88.5% were males, while 11.5% were females. 52.5% diabetic, while 34.8% was overweight and, 16.5% was obese. A total of 62.6 % had multi-vessel coronary artery disease and 37.4% patients had single vessel involvement. In multivessel group vs single vessel group dipper were less (25.29% vs 44.23% p=0.02) and non-dipper were more (50.57% vs 3077% p=0.02), which is statistically significant. Comparison of individual parameters of BP between the multivessel and single vessel CAD, average night SBP (116.15±17.27 vs 109.17±14.91 p<0.05) and average night DBP (63.82±8.65 vs  60.87±7.77 p=0.01) were higher and statistically significant in multivessel group as compare to single vessel group.