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Archive for April, 2021

It was the final case on weekend Echocardiogram review day, I asked my fellow for a brief summary of the patient. 

A 5 -minute conversation

“Yes, sir, he is a 62-year-old male retired govt officer. He has a severely stenosed aortic valve, with a peak gradient of 90 mmHg and a mean gradient that comes to almost 50 mmHg. LV  EF is 58%, GLS is 18, LVH is obvious. LA is not dilated (Didn’t measure volume though), but DT is short. Valve orifice is hovering around 1cm, mild calcium noted in LCC  I am not sure whether it’s bi or tricuspid still. The annulus is 22mm. The mitral valve is perfect, no calcium spill over to the mitral curtain and the rest of the annulus”.

“That is ok, what for he has come”?

“A GP from Tambaram has referred him after he detected a murmur over the chest”.

“Oh Ok. What are his symptoms”?

“He is denying any symptoms”.  

“Are you sure? did you ask him specifically about it during exertion”? 

“Yes, he says he can climb 3 flights of stairs. (In fact, he was sort of amused when I told him to be frank in his expression,since  he has a potentially serious obstruction in the main valve that connects his heart and body.”

“I agree, but his reaction was not inappropriate I thought, after all, he didn’t feel any symptoms right”. “So what shall we do for him?  TAVR? SAVR? or Leave him alone? Shall we put him on the treadmill? to document symptoms? Is it that risky”? 

“But , he says he can walk for a mile or two every day” 

“That’s fine. Can you really predict when his ventricle will fail and he may land up in a semi-emergency surgery?

“I think we can’t,  but why is he is so asymptomatic sir”?

“Wow, that’s more than a million-dollar question. You need to address that query to the vascular Goddess. I don’t know the answer.It is all about the ability of the heart to perfectly balance the ventricle and aorta in spite of severe obstruction. It is something like TIMI 3 flow and good FFR  in a patient with 90% occlusion.) My guess is, the LV does this by modulation of systemic pressure &  resistance in such a way , it neither feels the strain nor does it reduce the stroke volume much. By the way,  have you heard about this ? Z- Va score. I would like you to read about that. It will help you understand the hemodynamic nuances of severe AS and how the ventricle manages to serially couple the afterload of the vascular system”. 

“Make a pardon sir, I haven’t heard about it. What is Zva? 

“Never mind. It is not a new index. Was first introduced 16-years ago by Martin Briand et al from Quebec, heart Institute Canada  J Am Coll Cardiol 2005 Jul 19;46(2):291-8.  Z Va score(Valvulo-Arterial) is the collective flow impedance of the aortic valve and the entire aorta. It is more attractively defined as the cost of blood pressure in mmHg for pushing one ml of blood per body square meter area

Formula for Z va : (Systolic BP × Mean gradient)/ Stroke volume Index

Unit : mmhg /ml/m²

Normal value:  < 3.5 to 4.5 (Actually no normality, rather it must be acceptable value .It is still being defined )  if the cost is more than 5mmhg it suggests significant Aortic stenosis) A high value > 4.5 is a definite index of poor outcome. In a well-compensated heart, Zva is maintained far less than 5 and many such patients are asymptomatic as well. Zva has specific clinical value in all critical AS especially so if they are asymptomatic. It is no longer a research topic, has an important role in the bedside too. Here is an excellent resource on Z Va score from ESC.

 

Final message 

The timing of AVR in aortic stenosis is very critical. All symptomatic severe AS must be immediately intervened. Currently, with surgical risk falling rapidly ( & the option of TAVR looming large) even many of the asymptomatic AS need to be considered for valve intervention at the earliest before or at the onset of LV dysfunction. Zva’s score will definitely add more light to our  limited hemodynamic wisdom in aortic stenosis(Zeineb Hachicha  JACC 2019) 

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ASD device closure has become a de-facto modality for most ostium secundum defects(<35mm). The stupendous success of this procedure is attributed to careful pre and Intra-procedural Imaging, new generation hardware and of course the ever-improving expertise among Interventional cardiologists.

Still, there is one issue that is bothersome. It is the late complications of this device and the need for follow-up (Unlike surgery where close and forget option seems real and confer lot of comforts) The delayed mechanical complications are now extremely rare still  follow up of these patients is advised.

What is the mechanism of Aortic erosion in ASD device closure ?

The IAS is a dynamic structure. (Ask any echoc’ardiographer ,how ASD size varies with cardiac cycle.) The device should sit right across all rims including the  Aortic rim . If the device if larger , and if the Aortic rim is less it has on other option but to splay over the Aorta . Enthusiastic young cardiologists should be aware this splaying is not in our control at all. Not all splaying are good and safe as well. If its not smooth and if the septum is mal-aligned there could be friction Injury to Aorta. A very early manifestation of device dislodgement and later a trickle of  pericardial effusion. This should be watched for. (Please be reminded a early pericardial minimal effusion due to sudden shrinkage of RA, RV and due to some unknown hypersensitivity response ? can confuse us )

Link between deficient Aortic rim and Erosion : An unsettled Issue (But , we settled it ! )

One issue that is poorly understood is, many Interventional cardiologists believe strongly that the length (and even quality) of Aortic rim is the least important and need not to be respected. I am still not clear on what basis this piece of Interventional literature came in. This is exactly is the reason even novices take liberty and large devices are implanted casually encroaching the Aorta. Though most cardiologists shrug of this risk of Aortic rim deficiency and subsequent erosion,  at least one study clearly showed a serious link between the two. I feel the issue is not yet settled and demands re-scrutiny.

This presentation was made in Tamil Nadu Interventional (TIC)council meet at held recently

 

This image has an empty alt attribute; its file name is aortic-erosion-2-1.gif

Link to the PPT presentation aortic erosion 2

Final message 

After going through all relevant literature as on 2019 , the incidence of aortic erosion is rare but the fear is real (Many feel it is paranoid and largely unfounded ) I won’t agree though.The message must be, a good quality Aortic rim is important too.

However, a properly sized device, perfectly delivered with good Image assistance by a trained cardiologist in a high volume center (? >25/year) shall prevail over surgery in most patients with ASD. 

Reference

 
 
 
 
 
Further issues : Stroke risk with ASD device 
 

One more Issue with ASD closure device is delayed embolic episodes from thrombus attached to device. This is prevented by  routine anti platelet drugs practiced by certain Institutions .The new generation devices (Occlutech Germany) has modified the LA side of the disc (No Hub) to reduce this risk

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Some of the questions  addressed  in this presentation

1.What happens to fetal blood pressure during maternal hypotension how good is fetal autoregulation?

2.Why is LSCS increasingly preferred mode of delivery in heart disease complicating pregnancy challenging the traditional scientific concept?

3.What is likely hood of patients with moderate mitral stenosis developing pulmonary edema during prolonged 2nd stage of labor?

3.What is the missing link between PIH and PPCM? How prepartum cardiomyopathy differs from postpartum?

4.Is Eisenemneger really an absolute contraindication for pregnancy?

5. How can we continue VKAs warfarin or Acitrom throughout pregnancy? What are the potential problems of double switching one at 6th week from VKA to Heparin and again from heparin to VKA  at  12th week?

Hope, the man-made hematological bridge in pregnancy has been finally liberated from confusion (Who is saying not yet?)

 

6. On what evidence base the safety margin of 5mg cutoff for Warfarin and 3mg for Acitorm was decided?

7. Who is insisting on us to do Anti-Xa monitoring for LMWH in pregnancy? Is it really needed? What does the American society of hematology say?  (ASH guidelines for VTE in pregancy 2018) Why we don’t insist on Xa estimation in acute coronary syndrome?

8. What is the inflection point of at which risk of termination is almost at equipoise with continuing pregnancy in various heart diseases.

A GIF run-through of the presentation.

PDF & video version will be posted

 

The ultimate reference 

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