Feeds:
Posts
Comments

Posts Tagged ‘kaplan’

idh

  • Hypertension  is  major determinant of cardiovascular health  of our global population
  • Millions suffer,   hundreds of societies ,  and as many guidelines , and drugs are still struggling  to control the menace.
  • An important sub group of HT , (ie IDH ) population has been neglected and never received the scientific interest , which it deserves !
  • In our study it occured in 7.2% of all HT  patients.
  • JNC,  the world authority on HT never considered  IDH as a separate entity, and as of now there is no specific guidelines.
  • And the irony is complete . There is not  a  major study available to analyse the differential effects of anti hypertensive drugs on systolic and diastolic blood pressure.

If  a patient with the BP of 120/96 asks you , “Doctor , will the drug,   you have prescribed , selectively lower my diastolic blood pressure ” what will be your answer ?

A clear ,  I don”t know !

The following paper was presented in the World congress of cardiology Sydney  2002

Isolated  Diastolic Hypertension

S.Venkatesan,S.D.Jayaraj.Gnanavelu, Madras Medical College. Madras, India.

Abstract : Systemic  hypertension  continues to  be a major determinant of cardiovascular  morbidity. While isolated systolic hypertension(ISH) has been identified as a specific clinical entity, isolated  diastolic  hypertension(IDH) has not been reported as a separate group. When we analysed our data from our hypertension   clinic  we found  a distinct subgroup of patients who had  elevated  diastolic blood pressure   with  normal systolic pressure. We report the clinical profile of these patients. 440 newly registered hypertensive  patients between the year 1998-99  formed the study population. All  patients with secondary hypertension  were excluded.. IDH  was defined as  diastolic BP more than 90mmhg and systolic BP less than 140mmhg.

IDH was present in 32(7.2%) patients.  The male female ratio was 3:1, mean age was 42(Range32-56) The mean diastolic pressure was 96 mm (Range 90-110).The mean systolic pressure was 136mm(Range 128-140). LVH was observed in 4 patients(12.5%). Diastolic dysfunction was detected by echocardiography   in 20patients.(62%)

We conclude that isolated diastolic hypertension  constitute a  significant subset among  hypertensive  patients and they need further study regarding the pathogenesis, clinical  presentation and  therapeutic implication.

Link to PPT  will be available soon .

Read Full Post »

                                Hypertension is the most common clinical  cardiovascular entity.Left ventricular hypertrophy (LVH) is  an important consequence of  HT.In fact, it is considered as a end organ effect or damage. Others being brain, kidney, and peripheral vascular disease.Knowing about LVH is important because it has been linked to increased cardiovascular events.

lvh-4

                              Though LVH is considered  as a close companion of  HT  it is  surprising  only a minority (15-30%)  show evidence of LVH .Some  experienced clinicians (Level C evidence)  quote even lower < 10 %  .Traditionally LVH was detected by ECG and now it is replaced by echocardiography.

What determines the LVH ?

It will be suprising to note , answer to this question  is  still not  clear .

  • Is it the duration of elevated blood pressure ?
  •  Is it the absolute level of blood pressure ?
  • If so , is it  the systolic BP  , diastolic BP or the mean BP ?
  • Or is it related to the etiology of HT ?
  • There has been no significant correlation between the above parameters

When we don’t know  the answer to a question in medicine , the answer will  generally will be inside the genes !

So in HT also the major determinant of LVH is in the genes that determine the myosin heavy chain  response .

and also ACE gene polymorphism.ACE genes are involved in the expression of growth factors within the myocardium.

An excellent study  on the issue http://www.nature.com/jhh/journal/v17/n3/full/1001523a.html#tbl1

It implicates , gender, age, race etc in the genesis of LVH

Final message

So , the  myocardium does not respond with LVH   in all patients with HT.It happens only in a minority* .Duration of HT can be an important determinant , but  the major factor is  the alteration of genetic switches  within the myocytes How this switches are going to  behave ,  is largely inherited .Regression of LVH is also not uniform again implying lesser role for hemodynamics. (Some studies revealed ACEI have maximum regression  of LVH , later disputed )

*LVH is more consistently seen  in hypertension due to reno vascular  or parenchymal disorders .It is also an observed fact , a  combination of diabetes and HT is more likely to result in  LVH.

The other major issue  that needs explanation in HT/LVH  is   , how much of LVH is due to  myocyte hypertrophy perse  and how much is contributed by interstitial cell hypertrophy(Non myocytic hypertrophy)

This issue will be discussed soon

Read Full Post »

                    circulatory                                                                            A normally  functioning  circulatory system is vital for our survival . We have about 6000 ml of  blood, circulating  all over the  body in an  approximate time of 15-20 seconds.The pressure at which this blood moves across the body is called the blood pressure . Hypertension  or simply , high blood pressure is an undesirable  hemodynamic disturbance  in human circulatory system.Systemic hypertension is the most common type of hypertension. The blood pressure is primarily  dependent  on the status of the blood vessel(vascular resistance)  and cardiac contractility. This regulation is under  many neural and hormonal factors.Further  the blood pressure varies depending  upon the blood vessel calibre, and the local milieu.There is a progressive drop in blood pressure from major arteries to the small arteries .The pressure drop is maximum  across the arterioles to reach the venules .The venous circulation has the lowest pressure, it ends up at right atrium with a mean pressure of 0- 5mmhg.

Importance of regional variation of blood pressure.

It should be realised  ,  each organ has it’s own regulated blood pressure.The brain  perfuses by the  intracerebral pressure .The lungs decide how much should be the pulmonary arterial pressure.The kidney not only controls it’s own pressure but also  has a major regulatory role in  systemic pressure by rennin angiotensin system.The examples are numerous, portal system has it’s unique pressure controlling hepatic hemodynamics. The  retinal blood vessels regulate  intra ocular pressure. While the human  circulatory system has a wide variation of blood pressure  across the breadth and length of vascular system,  it is ironical a single snap shot BP with a brachial cuff is used  to define the normality and if it is normal every thing is thought to be  hunky dory !

 

 

It is widely acknowledged now , aging of humanity  is nothing but aging of our vascular system

                                    So we should have new parameters to assess individual organ’s vascular health as well as the currently popular systemic vascular health.The single important factor that determine coronary endothelial damage is the intra coronary pressure.It is never taken into account in any of the cardivascular mortality studies. This is the prime reason for  the widely prevalent conflict in the cardiology literature , namely : Controlling systemic  blood pressure has poor correlation with  cardiovascular outcome. Many of the so called normotensive individuals  have serious hemodynamic injury in their  coronary arteries.This was made apparent in the  ASCOT LLA  study , in which patients with  near normal blood pressure also benefited from statin therapy , implying  endothelial damage could occur at any level of systemic blood pressure.

What is the normal intracoronary pressure  ? When do you diagnose intracoonary hypertension?

The normal intracoronary pressure is around 40mmhg . Intra coronary hypertension as a clinical entity  is yet to be  recognised . There is no defintion available for intracoronary HT  , intracerebral hypertension as well. 

It’s still a  long way to  go , for the cardiology and neurology  community to assess non invasively  intracoronary pressures and  intra cerebral arterial pressure to prevent  coronary events ant strokes.

Final message

Simple risk prediction using brachial cuff blood pressure is a grossly unscientific method (Sorry, i really mean it ) to assess one’s vascular health.There has been  few attempts like vascular endothelial health assessment by fore arm blood  flow , central aortic pressure (Instead of brachial cuff pressure) as an  index for risk predictment and  assessment for hypertension is suggested.

Read Full Post »