title: Left ventricular responses to acute changes in late systolic pressure augmentation in older adults.
abstract: BACKGROUND
  Changes in the cardiovascular system with age may predispose older persons to development of heart failure with preserved ejection fraction. Vascular stiffening, aortic pressure augmentation, and ventricular-vascular coupling have been implicated. We explored the potential for acute reductions in late systolic pressure augmentation to impact left ventricular relaxation in older persons without heart failure.
  
  
  METHODS
  Sixteen older persons free of known cardiovascular disease with the exception of hypertension had noninvasive tonometry and cardiac ultrasound to evaluate central augmentation index (AI) and diastolic function at baseline and after randomized, blinded administration of intravenous B-type natriuretic peptide (BNP) and hydralazine in a crossover design.
  
  
  RESULTS
  AI was significantly reduced after BNP (11.4±8.9 to -0.2±14.7%; P = 0.02) and nonsignificantly reduced after hydralazine (14.7±8.4% to 11.5±8.8%; P = 0.39). With decreased AI during BNP, a trend toward worsened myocardial relaxation by tissue Doppler imaging occurred (E' velocity pre- and post-BNP: 10.0±2.5 and 8.8±2.0cm/s, respectively; P = 0.06). There was a significant fall in stroke volume with BNP (68.5±18.3 to 60.9±18.1ml; P = 0.02), suggesting that changes in preload overwhelmed effects of afterload reduction on ventricular performance. With hydralazine, neither relaxation nor stroke volume changed.
  
  
  CONCLUSIONS
  Acute changes in late systolic aortic pressure augmentation do not necessarily lead to improved systolic or diastolic function in older people. Preload may be a more important determinant of cardiac performance than afterload in older people with compensated ventricular function. The potential for changes in preload to impair rather than enhance left ventricular systolic and diastolic function in older people warrants further study.
  
  
  BACKGROUND
  This study is registered at clinicaltrials.gov as NCT00204984.
authors.affiliation: Division of Cardiovascular Medicine, University of Wisconsin, Madison, Wisconsin, USA. nks@medicine.wisc.edu
authors.forename: Nancy K
authors.initials: NK
authors.lastname: Sweitzer
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Hetzel
authors.forename: Joseph
authors.initials: J
authors.lastname: Skalski
authors.forename: Mauricio
authors.initials: M
authors.lastname: Velez
authors.forename: Kevin
authors.initials: K
authors.lastname: Eggleston
authors.forename: Gary F
authors.initials: GF
authors.lastname: Mitchell
mesh_terms: D000368:Aged; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000627:therapeutic use; D001794:Blood Pressure / Q000502:physiology*; D018592:Cross-Over Studies; D018450:Disease Progression; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D015150:Echocardiography, Doppler; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology*; D006801:Humans; D006830:Hydralazine / Q000008:administration & dosage* / Q000627:therapeutic use; D006973:Hypertension / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology*; D007262:Infusions, Intravenous; D008297:Male; D045283:Natriuretic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D020097:Natriuretic Peptide, Brain / Q000008:administration & dosage* / Q000627:therapeutic use; D013318:Stroke Volume / Q000502:physiology; D013599:Systole; D016896:Treatment Outcome; D059289:Vascular Stiffness / Q000187:drug effects / Q000502:physiology; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology*
chemical_list: D000959:Antihypertensive Agents; D045283:Natriuretic Agents; D020097:Natriuretic Peptide, Brain; D006830:Hydralazine
keywords: arterial stiffness; arterial wave reflection; blood pressure; cardiac performance; hypertension.
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