A blunting of the nocturnal fall in arterial blood pressure is found in a minority of patients (nondippers) with essential hypertension. We tested whether sleep-disordered breathing (snoring and apnea or hypopnea) might explain such a finding for male patients, among whom its prevalence is much higher.
We studied 100 new cases of hypertension in men, observed consecutively by a local group of general practitioners and diagnosed essential hypertensives in a referral clinic. By using 24 h ambulatory blood pressure monitoring with a SpaceLabs 90207 device, 15 patients were classified initially nondippers (daytime ambulatory blood pressure ≥ 136/87 mmHg; night-time decrease by < 10% of the daytime mean), but only 11 were confirmed to be nondippers by continuous blood pressure monitoring with a Finapres device. Ten dippers matched by age, body mass index and mean 24 h blood pressure were used as controls.
measures Parameters of nocturnal polysomnography.
During polysomnography, the nondippers exhibited a blunting of the sleep-related fall in blood pressure and an increased variability in blood pressure associated with sleep-disordered breathing (heavy snoring for all, with an apnea or hypopnea index > 10 in 10 cases). Six of the control patients breathed normally and four snored nonapneically. There was a normal fall in nocturnal blood pressure in all 10 cases.
The nondipper condition appears to be associated with undiagnosed apneic snoring for an unselected population of previously untreated male subjects with a diagnosis of essential hypertension. Ambulatory blood pressure monitoring of such patients is of limited diagnostic value.
1Hypertension Unit, First Section of Internal Medicine, Department of Clinical and Experimental Medicine, University of Ferrara, Ferrara, Italy
2Neurological Institute, University of Bologna, Bologna, Italy.
3Requests for reprints to Dr Francesco Portaluppi, Hypertension Unit, First Section of Internal Medicine, Università di Ferrara, via Savonarola 9, I-44100 Ferrara, Italy.
Sponsorship: This study was 60% supported by a grant from the Italian Ministry of University and Scientific and Technological Research.
Received 6 February 1997 Revised 8 July 1997 Accepted 21 July 1997