Nighttime blood pressure might be the key for checking your risk of CV disease

by Dr. Alan Kadish

The essence of this study is the statistically useless nature of the in-office taking of blood pressures during the day, as compared to overnight and specifically nighttime blood pressure values.

This is the only long term (1 yr), 13,000 patient studies that can really give us insight into the best predictors of when and how monitoring B/P will give us real data as to who is at risk, for both CV disease and strokes.

Unlike our colleagues in Europe, in the United States we use a very limited number of studies to measure our patient’s overnight blood pressures. However, it now is clear that for those of us wanting a good risk analysis, for patients who have elevated blood pressures, we should have this information.  

The statistics suggest that those of us who experience an increase of every 10mmHg during the evening measurements, we have a ~25% increase in risk of the dreaded cardiovascular “events” (heart attacks and strokes). This is one of two studies that addressed the overnight observation and concluded similar findings.

The theory is that the nighttime hypertension is a marker for elevated sympathetic tone which should decline preferentially during the evening hours . It makes sense that we should put our feet up and relax. However this is not the case as indicated by the elevated blood pressures, with many in this study.

The increased sympathetic tone adversely impacts risks for both strokes and heart-attack. The elevated blood pressure also will be exposing the brain and heart to an increased blood-pressure load for an extended period of time, resulting in not only increased risk, but also a myriad of other possible negative life impacting effects. 

Conclusion……it does make a difference if you relax during the evening hours physiologically and how your quality of sleep and evening activities ultimately impacts your overall health.

In our cardiometabolic assessments we will be looking at all the indicators that lead to increased risk issues. Here is another example of a non-invasive means of knowing how your cardiovascular system responds when your asleep.

Please feel free to contact the Center for a full evaluation that allows for an accurate and comprehensive insight into your health.

Prognostic impact of clinic, daytime, and nighttime systolic blood pressure in 9 cohorts of 13,843 patients with hypertension: systematic review and meta-analysis

  • George Roush, for the ABC-H Investigators, Robert Fagard, Gil Salles, Sante Pierdomenico, Gianpaolo Reboldi, Paolo Verdecchia, Kazuo Eguchi, Kazuomi Kario, Jorge Polonia, Alejandro de la Sierra, Ramon Hermida, Eamon Dolan, Hernan Zamalloa

Whether ambulatory daytime systolic blood pressure (DSBP) predicts cardiovascular events (CVEs) independent of nighttime SBP (NSBP) and clinic SBP (CSBP) is unclear. We sought to answer this question in hypertensives. A systematic review of the literature was conducted and lead investigators were contacted. Inclusion criteria were a diagnosis of hypertension, 1+ years of follow up, and CVEs as outcomes. Coefficients of variation of SBP and 95% confidence limits were computed. Random effects meta-analyses were used throughout. Nine Cohorts (N=13,843) were from Europe, Brazil and Japan. As measured by coefficients of variation, dispersion for NSBP exceeded that for DSBP by 21.7%. For a 10 mmHg increase in NSBP, DSBP, and CSBP, each measure predicted CVEs when considered individually: HRs (95% confidence intervals) =1.25 (1.22-1.29), 1.20 (1.15-1.26) and 1.11 (1.06-1.16), respectively. However, after simultaneous adjustment for all 3 BPs, HRs were 1.26 (1.20-1.31), 1.01 (0.94-1.08) and 1.00 (0.95-1.05), respectively. For the 6 cohorts with the highest quality, HRs were 1.27 (1.20-1.34), 1.01 (0.91-1.11) and 1.00 (0.97-1.04), respectively.

Patterns were similar when CAD and stroke were considered separately. In conclusion, in this meta-analysis of hypertensive patients (the largest study of its kind), NSBP has greater dispersion than DSBP and independently predicts CVEs, while neither DSBP nor CSBP does so.

References

  1. Roush G, Fagard R, Salles G, et al. Prognostic impact of clinic, daytime, and nighttime systolic blood pressure in 9 cohorts of 13,843 patients with hypertension: systematic review and meta-analysis. J Am Soc Hypertens 2014; 8:e59.
  2. Niiranen T, Puukka P, Mäki J, et al. Office, home, and ambulatory blood pressure as predictors of cardiovascular risk. J Am Soc Hypertens 2014; 8: e3-e4. Abstract

Copyright Center of Health™ 6/2014  For permission to reprint this article, please contact the author.

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Dr. Kadish is an unusual physician often referred to as a "doctor detective". His expertise is the evaluation and treatment of complex disorders, typically after other physicians have been stumped, is renowned. He provides care for all family members and has additional training in autistic spectrum disorders and chronic complex diseases.