Is Scar Really A Gift?

Well, to answer this particular question, I'll illustrate it with my PACES case. As I've shared earlier on of my neurology case in station 3, this would be the continuation of what had happened after that.

The same pair of nice examiners had ushered me into another room.

An elderly gentleman had already been properly exposed and positioned propped up at 45o.

"Please examine the cardiovascular system and tell us your findings."

Again, a rather simple stem. Nothing fancy.

I quickly noticed a midline sternotomy scar on the patient. I gathered my clinical experience and in my mind, I had these possibilities outlined:

1. Patient had a valve replacement done, either metallic or bioprothetic - this is by far the commonest scenario encountered in PACES with sternotomy scar
   
2. Possible valve repair
3. Patient had a CABG done - ?evidence of venous harvest
4. Patient had sternotomy for excision of cardiac tumours or masses eg, atrial myxoma, resistant IE etc or closure of large septal defects
   
5. Sternotomy for non-cardiac surgery eg, thymectomy, repair of other midline structures etc. - this is highly unlikely in PACES station 3!

I proceeded to pick up his hands and started examining the peripheries. The only positive sign was of an irregularly irregular pulse at about 60-70bpm. There were no stigmata of IE and in particular, I could not see any scar of previous venous harvest both in the upper and lower limbs.

He was pink on air and there was no jaundice. The venous pressure is not elevated and, as mentioned earlier, there was a midline sternotomy scar which was well healed. There was no scar elsewhere at the precordium.

At this juncture, I gathered that the positive signs were:

1. Rate-controlled AF
2. Midline scar

I told myself that I should be looking hard for a mitral valve pathology hence needing surgical intervention, with the distant possibility of a previous large ASD now closed.

On examination of the precordium, the apex beat is not displaced. There was no thrill. The were no signs of raised pulmonary pressure. The first heart sound was loud and the second heart sound was well heard. There were no other added sounds. There was no signs of cardiac failure and no signs to suggest overwarfarinisation.

"So what do you think?"

"I think this gentleman has had a mitral valve replacement done, complicated by atrial fibrillation currently rate-controlled. There was no signs of cardiac failure. There were no metallic sounds heard on auscultation and hence it cannot be a metallic valve. It is possible that this gentleman has had a bioprosthetic mitral valve implanted."

"Are you sure? What would be the other possibilites?"

"It is still possible that he had a mitral valve repair done previously."

"Which one do you think is more likely?"

"I think a valve replacement would be more likely as the presence of atrial fibrillation would indicate the chronicity of the mitral valve pathology, which is, mitral stenosis in this case in view of the undisplaced apex beat. A valve repair is usually being employed to ameliorate a less severe or chronic valve pathology."

"Ok then, you say that it is a bioprothesis. Would you still want to give this patient warfarin?"

"Yes. I would like to anticoagulate this patient for the indication of atrial fibrillation."

"Why is that so?"

"To reduce the risk of thromboembolism. Warfarin is shown to be superior than aspirin alone in preventing thromboembolism, for example stroke, which causes significant morbidity and mortality."

"Do you know the percentage of thromboembolic risk reduction by giving patients warfarin?"

At this time, the bell went.

Verdict: 4/3