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Heart Rate and Diastolic Blood Pressure vs. Chronic Aortic Regurgitation Mortality
Study Questions:
Are diastolic blood pressure (DBP) and resting heart rate (HR) associated with all-cause mortality among patients with hemodynamically significant chronic aortic regurgitation (AR)?
Methods:
Consecutive patients with moderately severe or severe AR on presumably clinically indicated transthoracic echocardiography (TTE) from 2006 to 2017 were retrospectively identified. Patients with at least mild mitral regurgitation and/or aortic stenosis, active infective endocarditis, or prior valve surgery were excluded from analysis. Clinical data were extracted from the medical record. Resting HR and manual or automated blood pressure were routinely assessed among all patients undergoing TTE. Assessment of mortality was based on electronic medical record review and a proprietary resource linking multiple national resources, and was censored at the time of aortic valve replacement. The association between all-cause mortality and routinely measured DBP and resting HR was examined.
Results:
Of 820 patients retrospectively identified (age 59 ± 17 years, 82% men) and with 5.5 ± 3.5 years of available follow-up data, 104 died under medical management, and 400 underwent aortic valve surgery. Age, symptoms, left ventricular ejection fraction (LVEF), LV end-systolic diameter-index (LVESDi), DBP, and resting HR all were univariable predictors of all-cause mortality (all p ≤ 0.002). When adjusted for demographics, comorbidities, and surgical triggers (symptoms, LVEF, and LVESDi), baseline DBP (adjusted hazard ratio [HR], 0.79; 95% confidence interval [CI], 0.66-0.94 per 10 mm Hg increase; p = 0.009) and baseline resting HR (adjusted HR, 1.23; 95% CI, 1.03-1.45 per 10 beat per min [bpm] increase, p = 0.01) were independently associated with all-cause mortality. These associations persisted after adjustment for the presence of hypertension, medications, time-dependent aortic valve surgery, and using average (presumably clinically obtained within 2 weeks of the TTE) DBP and resting HR (all p ≤ 0.02). Compared to the general population, patients with AR exhibited excess mortality (relative risk of death >1), which rose steeply in inverse proportion (p nonlinearity = 0.002) to DBP starting at 70 mm Hg and peaking at 55 mm Hg, and in direct proportion to resting HR starting at 60 bpm.
Conclusions:
In patients with chronic hemodynamically significant AR, routinely measured DBP and resting HR demonstrated a robust association with all-cause death; independent of demographics, comorbidities, guideline-based surgical triggers, presence of hypertension, and use of medications. The authors concluded that DBP and resting HR should be integrated into comprehensive clinical decision-making for these patients.
Perspective:
Among patients with chronic AR, low DBP (associated with a wide pulse pressure) might be a sign of disease severity. In theory, a low resting HR (due to a longer diastolic interval) could promote worse AR; although a high resting HR usually is an indicator of poor compensation for an underlying regurgitant valve lesion, and potentially heralds a worse prognosis. The current management of chronic AR includes avoidance of bradycardia and avoidance of a marked reduction of DBP. This large, retrospective, single-center study demonstrates that low DBP and high resting HR both were associated with excess all-cause mortality. A causal relationship was not established between DBP and resting HR and all-cause mortality, cardiac mortality was not assessed, and it is unknown whether aortic valve intervention among patients with AR and low DBP and/or high resting HR (with no other indications for intervention) affects outcome. Although the findings are provocative, additional study would be required in order to define the clinical significance of these observations.
Clinical Topics: Arrhythmias and Clinical EP, Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Prevention, Valvular Heart Disease, Implantable Devices, Aortic Surgery, Cardiac Surgery and Arrhythmias, Cardiac Surgery and Heart Failure, Cardiac Surgery and VHD, Interventions and Imaging, Interventions and Structural Heart Disease, Echocardiography/Ultrasound, Hypertension
Keywords: Aortic Valve Insufficiency, Blood Pressure, Blood Pressure Determination, Bradycardia, Cardiac Surgical Procedures, Diagnostic Imaging, Diastole, Echocardiography, Heart Rate, Heart Valve Diseases, Hypertension, Primary Prevention, Stroke Volume
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