MYOCARDIAL MECHANO-ENERGETIC EFFICIENCY AND CLINIC AND 24 HOURS BLOOD PRESSURE VALUES IN PATIENTS ATTENDING THE OUTPATIENT CLINIC AT AN ESH EXCELLENCE CENTRE IN ITALY

Abstract

Objective: It has been demonstrated that low myocardial mechano-energetic efficiency index (MEEi),estimated as stroke volume/heart rate ratio per g of left ventricular(LV) mass(LVM) is an independent predictor of cardiovascular(CV) events. Out of office blood pressure (BP) is better correlated to hypertension mediated organ damage(HMOD) and to CV events as compared to BP measured in the office. Design and method: Aim of the study was to evaluate the relationship between myocardial mechano-energetic efficiency index and both clinic and 24 hours BP values in 839 consecutive uncomplicated patients attending the outpatient at an ESH Excellence Centre in Italy. Methods BP values were measured by the physician with an automated oscillometric device, after 5 minutes of rest. ABPM was performed in all subjects with a Spacelabs BP monitor. All patients underwent transthoracic echocardiography, and standard indices of systolic function were calculated. Furthermore in all patients myocardial mechanoenergetic efficiency (MEE) was calculated as stroke volume/heart rate and indexed to LV mass (MEEi=MEE/LVM) (de Simone et al, 2016). Results: Mean age was 53 ± 14 yrs, 53% female, BMI 26 ± 5, 34 % were overweight, 18% obese, 8% % diabetics, 64 % with a previous diagnosis of hypertension(71 % treated). MEEi was lower in males (0.41 ± 0.14 vs 0.52 ± 0.15), and in patients with diabetes(0.40 ± 0.11 vs 0.48 ± 0.16). MEEi was inversely -correlated with age(r = -0.146, p < 0.0001) and BMI(r = -0.353, p < 0.0001). MEEI was similarly correlated to 24 hours SBP and clinic SBP(respectively r = -0.267, p < 0.0001 and r = -0.196, p < 0.001, Steiger's Z test for the comparison p ns) and to 24 hours DBP and clinic DBP(r = -0.249, p < 0.0001 and r = -0.248, p < 0.001, Steiger's Z test for the comparison p ns). However, at receiver operating curves(ROC) the area under the curve(AUC) for 24 hours SBP(0.627, 95 % CI 0.593 - 0.659) was superior in predicting low MEEI (defined as < 0.35) as compared to the AUC of clinic SBP(0.582, 95 % CI 0.548 - 0.615)(p for the comparison < 0.05). Conclusions: In a large sample of uncomplicated patients attending the outpatient clinic at an ESH Excellence Centre in Italy 24 hours BP is a better predictor of reduced myocardial myocardial mechanoenergetic efficiency than clinic BP.