Hypertension in Aortic Valve Disease

Transcription

1 Hypertension in Aortic Valve Disease Hanna M. Nosseir MRCP, FRCP Head of Cardiology department Galaa Military Medical Complex

2 Aortic stenosis: Introduction Arterial hypertension and aortic stenosis are common disorders and are frequently present concomitantly especially in the elderly. Clinical presentation of aortic stenosis is affected by the cardiac heamodynamic impact of co-existant hypertension. This interaction was not thoroughly discussed in the guidelines of management of either disease. The prevalence of hypertension is 30-45% in the general population and increases steeply with age. The prevalence of aortic stenosis is 3% in patients over 75 years.

3 Aortic stenosis:epidemiology

4 Aortic stenosis:epidemiology In the Cardiovascular Health Study, which enrolled 5201 subjects aged 65 years: Aortic valve sclerosis was present in 37%. Aortic valve stenosis in 2.6% of subjects aged 75 years. History of hypertension increased the risk of stenosis by 23%.

5 Aortic stenosis: Main Causes Senile Rheumatic Congenital bicuspid aortic valve.

6 Aortic stenosis: Mechanism of interaction Hypertension has been associated with a faster progression of AS severity which was explained by: Hypertension results in abnormally high tensile stress on aortic leaflets. Alternatively, turbulent flow patterns associated with high volume flow rates may lead to abnormal shear stress, endothelial injury and disruption, as seen in atherosclerotic lesions.

7 Aortic stenosis: Mechanism of interaction Hypertension: Significantly influences LV geometry Is associated with higher LV mass, relative wall thickness and prevalence of LV hypertrophy Leads to reduced systemic arterial compliance Leads to higher valvuloarterial impedance and total peripheral resistance. These are reflected on the increased ischaemic events, all cause mortality and cardiovascular mortality.

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9 Aortic stenosis: Clinical consequences Symptoms of AS develop with a larger aortic valve area (AVA) and lower stroke work in hypertensive patients. In patients with coexisting hypertension and AS, hypertension should be treated more aggressively to delay the occurrence of symptoms. These patients should be followed up more closely.

10 Aortic stenosis: Diagnosis A diagnostic and therapeutic challenge. When these two conditions coexist, the interplay between the two might be difficult to assess Hypertension and AS impose a significant overload on the left ventricle. In addition, hypertension encompasses a wide range of haemodynamic conditions from a prevalent volume overload to a prevalent pressure overload.

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13 Aortic stenosis: Diagnostic practical points Estimation of the double LV load (valvular and arterial) is feasible by calculating the valvulo-arterial impedance (Zva). This index is calculated by dividing the LV systolic pressure (systolic BP + mean transvalvular pressure gradient) by the stroke volume index. Values >4.5 mmhg/ml/m 2 are indicative of an excessively increased afterload. BP control is recommended before echocardiographic evaluation. The echocardiographic report should always include a BP measurement recorded at the time of the AV assessment (for clinical and echocardiographic comparison).

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18 Aortic stenosis: Treatment In addition to modification of atherosclerotic risk factors, the following should be considered: Never be reluctant to treat hypertension for the concern of reducing cardiac output. AS does not result in a fixed valve obstruction until late. ACC/AHA hypertension guidelines apply for patients who are asymptomatic and/or with mild AS. Maintaining sinus rhythm whenever possible is important.

19 Aortic stenosis: Treatment Moderate and severe AS Diuretics: Avoid in patients with small LV chambers to avoid low COP. Can be used in hypertensive emergencies. Can be used in patients awaiting a procedure: TAVI or surgery. Beta blockers: Use is mainly in patients with concomitant IHD

20 Aortic stenosis: Treatment Moderate and severe AS ACEI and ARBS: Potential role of ACE inhibitors in slowing the disease progression by modulating myocardial hypertrophy and fibrosis. (RAS) blockade improves effort tolerance and reduces dyspnea. Patients with congestive heart failure with LV dysfunction and baseline systolic BP mmhg are prone to hypotension. In a large observational study of 2117 patients followed for 4.2 years, the authors concluded that RAS inhibition therapy was associated with improved survival and a lower risk of CV events (CV death or hospitalizations).

21 Aortic stenosis: Treatment Moderate and severe AS Nitropruisside: Vasodilators are considered to be contraindicated in patients with severe AS because of concern that they may precipitate life-threatening hypotension May improve myocardial performance if peripheral vasoconstriction is contributing to increased afterload. Low starting doses and gradual up-tritation with invasive monitoring. Nothing was mentioned in the literature about preload reduction which reduce LV filling and need to be avoided in small LV cavity patients.

22 Aortic Regurgitation Mostly aortic regurge is chronic. Acute AR is much less common. Many causes are present for chronic AR. Haemodynamics are different from AS. It is a volume overload disease. Hypertension do exist with AR usually systolic. Echocardiographic features are those of LV dilatation and increased wall thickness (Eccentric LVH).

23 Aortic Regurgitation Management of hypertension in patients with AR is according to the current guidelines. ACEI and ARBS remain the mainstay of treatment. Vasodilating CCBs (amlodipine and others) are good options. Beta blockers in patients with IHD. Diuretics have the benefit of decreasing LV volume. Follow up of the patients clinically and by echocardiography to choose the best time for surgery.

24 Take Home Message Arterial hypertension and aortic valve disease are common diseases. The prognosis is worse when these disorders coexist. The evaluation of AS severity may be inaccurate when hypertension is uncontrolled. Diagnostic and interventional modalities are selected according to the specific patient profile. Medical therapy for hypertension in patients with AVD is important. In specific subgroups of AS patients, BP levels should be accurately defined before deciding AVR. Multidisciplinary team approach is mandatory and referral of the patient from the internist for cardiology opinion about management plan is necessary.