How do you tackle In-stent restenosis (ISR) ?
- Deploy another BMS
- Use a third generation DES
- No . . . first generation DES(Paclitaxel )
- Consider Plain balloon angioplasty.(POBA)
- Refer for CABG.
- Fall back on medical management.(Ingloriously referred to as “No option” patient !)
Answer: Please note , there is no single response answer for this question .
Instent restenosis (ISR) is commonly seen with BMS .This is primarily because we are busy blaming DES for stent thrombosis and we do not want to give a double blow to DES .There is a significant population roaming with ISR involving DES . BMS is in vogue for nearly 2 decades, hence it is natural to see more of it. In due course , DES is expected to catch up with BMS and would lead in ISR as well .
The issues in PCI for ISR
Though any of the above 6 strategies may be appropriate ,the urge to put another stent within the IRS , prevails over all other options in most centers. This is more off an Interventionist talent show off !
Please remember , the common principles must apply in all patients before an PCI . Simply stated , this principle involves assessing symptoms, residual resting ischemia, myocardium at risk during stress, viable muscle mass etc .Lesion characteristics should come last in the work up. ( A cardiologist should not report a coronary angiogram , if does not not know basic clinical parameters.)
It is good to have a rule that “reserves intervention” for ISR only if the patient has refractory angina.
Can you promise relief from dyspnea
Contemplating PCI for patients with dyspnea as the main symptom is really tricky one.Unlike angina , dyspnoea can be attributed to so many factors other than coronary blood flow.(Apart from LV EF , Iscehmic MR, A transient diastolic dysfunction , lung function , volume status, renal function , physical conditioning etc)
Opening ISR in the belief it would improve LV function is highly questionable even if viability is documented.
What is the most important step in the decision making prior to PCI for ISR ?
* Most important step in ISR management is probably spending sufficient time , involving experts , ” democratically debating” the indication and techniques in your institutional cath conference.
Once you document the necessity of intervention* The following things are possible .
- If the patient has diffuse in-stent stenosis , especially the proximal ones or that involves branch points, it is wiser to refer them for CABG.
- Discreet and focal ISRs can safely be attempted for repeat PCI.
- BMS or DES ? This is debated. Current preference is to use a DES. (Many feel ,first generation DES -(Paclitaxel) scores over Everolimus in this situation )
- Is POBA possible for IRS ? Can a balloon do a job where a stent has failed ? . No body is trying it .Many Feel guilty to do it . POBA for IRS is a failed concept without even trying it ! One way of reasoning is IRS occurred only because stent was never indicated in the first place in that location and a POBA would have been the choice in the initial attempt itself .So let us not make the second error ! ( May be , if Gruientzig is alive today , might have used POBA for ISR very effectively ! )
Issues for which we will never ever know the answer !
In future any of the following combination of stents will occur in tackling ISR.
- DES covered BMS
- BMS covered DES
- Two BMSs
- Two DESs
- Paclitaxel covered Everolimus
- Everolimus covered Cypher.
- Overlapped DES and BMS
- DES covered beta irradiated IRS
- Rotablated BMS (Yeh metal crushing !) followed with DES jacket !
How does the two metals , two drugs in various combinations interact with the tender coronary endothelium ?
Endothelium is an endocrine organ. It has to secrete as many pro and anti homeostatic molecules (Nitric oxide, endothelin etc).This has to be kept in mind when we develop newer and exotic devices. Of course , we claim our aim is primarily to provide relief to our ailing patients , but, as things stand today , there is a distinct risk of converting human coronary arteries into corporate playgrounds !
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